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NO MORE FLAMING HOW TO TEST COMPUTE LIKE A WHAT REALLY BATTERIES! A ROBOCAR… NERVOUS SYSTEM HAPPENED IN CUBA A new process makes without driving The resurgence of Sonic attack on the better lithium-ion cells it 200,000 miles stochastic computing U.S. embassy, or mishap? P. 34 P. 40 P. 46 P. 09

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28 34 40 46 Building a Safer, Driving Tests Computing Tv’s Quantum- Denser Li-ion for Self- With Dot Future Battery Driving Cars Randomness Manufacturing tricks Building a self-driving Stochastic computing A variety of technologies for tomorrow’s borrowed from Silicon vehicle isn’t enough— provides an unconven- Valley are packing more we need to prove that it’s tional way to compute TV displays rely on quantum dots. power into these cells. safe for our streets. more with less. By Zhongsheng Luo, Jesse Manders By Ashok Lahiri, Nirav By Erik Coelingh By Armin Alaghi & Jeff Yurek Shah & Cameron Dales & Jonas Nilsson & John P. Hayes

On the cover Illustration for IEEE Spectrum by Mark Montgomery osys n Na

SPECTRUM.IEEE.ORG | Mar 2018 | 01 DEPARTMENTS_03.18TMENTS_01.13

07 19 06 Online News Resources Opinion spectrum.ieee.org Ancient Statues Recast The Altair 8800...Now With Robo-Adjudication and Director’s Cut: Ted Nelson on From Digital Scans Bluetooth Fake Fraud Reports What Modern Programmers Can New replicas of old sculptures will An Arduino-based kit replicates Michigan’s MiDAS system falsely Learn From the Past soon be on display in Iraq. the first commercially successful identified thousands of its citizens Due to popular demand, we’ve By Michael Dumiak personal computer. as insurance cheats. released an extended version By Stephen Cass By Robert N. Charette of our interview with Nelson, in 09 Reverse Engineering a which he talks about the work of “Sonic Weapon” 21 At Work: The Legal Hazards of 03 Back Story Douglas Englebart, the origins 10 Ferroelectrics: The Ultralow- AR and VR 04 Contributors of Xanadu, and how he views Power Solution? 22 Tools & Toys: Crazy Gadgets 24 Internet of Everything: programming as an art. Watch it 12 India’s Troubled Biometric From CES Curb Your 5G Enthusiasm here: https://spectrum.ieee.org/ ID System 23 Careers: Hot Jobs in 26 Numbers Don’t Lie: moretednelson0318 14 The Big Picture: Silicon Valley Photovoltaics’ Early Days in Orbit Drones Take a Dive 56 Past Forward: 27 Reflections: Finding the Accuracy in Agriculture Right Wave to Ride

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Efficient Development of Electrical Drives Using FUTURE OF TELEVISION This month we feature what’s new in TV Model-Based Development technology, including the rollout of ATSC 3.0, the latest digital television transmission standard, as well as the emergence of roll-up displays and immersive audio.

White Papers useum Available at spectrum.ieee.org/whitepapers M THE BIG SCREEN In 1980, Mitsubishi Electric installed the first large-

scale color display system, at Dodger Stadium, in Los Angeles. The display ational

The Test Implications of Packaging Innovation N Calculation Management Done Right will be recognized this month with an IEEE Milestone. Gorman BREAK INTO BROADCAST Find out what skills are needed to get into elia the field of broadcast engineering. C ooman/Dutch ooman/Dutch L klett; klett; i d IEEE SPECTRUM

(ISSN 0018-9235) is published monthly by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved. © 2018 by The Institute of Electrical and Electronics Engineers, Inc., 3 Park Avenue, New York, NY ran ;

10016-5997, U.S.A. Volume No. 55, issue No. 3. The editorial content of IEEE Spectrum magazine does not represent official positions of the IEEE or its organizational units. Canadian Post International Publications Mail obbert-Jan (Canadian Distribution) Sales Agreement No. 40013087. Return undeliverable Canadian addresses to: Circulation Department, IEEE Spectrum, Box 1051, Fort Erie, ON L2A 6C7. Cable address: ITRIPLEE. Fax: +1 212 R 419 7570. INTERNET: [email protected]. ANNUAL SUBSCRIPTIONS: IEEE Members: $21.40 included in dues. Libraries/institutions: $399. POSTMASTER: Please send address changes to IEEE Spectrum, c/o Coding Department, IEEE Service Center, 445 Hoes Lane, Box 1331, Piscataway, NJ 08855. Periodicals postage paid at New York, NY, and additional mailing offices.C anadian GST #125634188. Printed at 120 Donnelley Dr., ntiquities

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02 | Mar 2018 | SPECTRUM.IEEE.ORG Kevin Fu C Sound of Silence weak results. to upendhis we aren’t concerned.Butwhen we that see itinthedata, upsetsus.” ways to sounds intheenvironment. at Fumentionedacolleague the respondwere thatdevicescan inunusual electronic thefact discussing University ofMassachusetts, whoseaidwould Amherst, hearing pickup used to control emitsound lighting, waves inaudible to humans. A high- ized the sensor might be messing withBolton’sized thesensormightbemessing experiment. The the‘SonicWeapon,’ ”neering issue.] inthis offendingtaken sensor was down. Fortunately, itssignal proved too the lightsstay on. changeis inthe inthereflectedsomeone soundroom, andso indicates abovethe ceilingright Bolton’s workstation. Such ultrasonicsensors, gation of another case of electronics behaving ofelectronics gation badly, ofanother case see“Reverse Engi- signals coming from a room-occupancy sensorandthentranslatesignals comingfrom aroom-occupancy the “There’s always someinterference,” Funotes.“Whenit’s low in “Look up,“Look Connor,” Futoldpointingto Bolton, asmallwhite box on A beatlater, justbefore thepictureabove was taken,real thetwo - BACK STORY_ freq When you’re experimenting withprecisely calibratedacoustic onnor Bolton, aPh.D. stu waves, it’s that essential extraneous signalsdon’t your distort data. whether sound waves inhard malfunctions trigger diskdrives. can ingly setupmicrophones, speakers, andotherequipment to test in AnnArbor, had arranged workstation his justso. He’d painstak uency chirps into anaudibleuency [To buzz. read about Fu’s investi- What hedidn’t consider, though, were sounds hecouldn’t hear. One day lastAugust, [above] Bolton advisor, andhis Kevin Fu, d ent

at theUniversity ofMichigan, tensit ■ y, -

03.18 CONTRIBUTORS_

Editor in chief Editorial Advisory Board Susan Hassler, [email protected] Susan Hassler, Chair; David C. Brock, Sudhir Dixit, Limor Executive Editor Fried, Robert Hebner, Joseph J. Helble, Grant Jacoby, Leah Armin Alaghi Glenn Zorpette, [email protected] Jamieson, Jelena Kovacevic, Deepa Kundur, Norberto Alaghi works at Oculus Research and Editorial Director, Digital Lerendegui, Steve Mann, Allison Marsh, Jacob Østergaard, Umit Ozguner, Thrasos N. Pappas, H. Vincent Poor, John Rogers, the University of Washington. In this Harry Goldstein, [email protected] Managing Editor Jonathan Rothberg, Umar Saif, Takao Someya, Maurizio issue, he and John P. Hayes of the University Elizabeth A. Bretz, [email protected] Vecchione, Yu Zheng, Kun Zhou, Edward Zyszkowski of Michigan write about stochastic computing Senior Art Director Managing Director, Publications Michael B. Forster [p. 46]. This approach was important back when Mark Montgomery, [email protected] transistors were hard to fabricate—and it could Senior Editors Stephen Cass (Resources), [email protected] Editorial Correspondence IEEE Spectrum, 3 Park Ave., 17th Floor, be valuable again. For example, some people Erico Guizzo (Digital), [email protected] New York, NY 10016-5997 hope to use proteins to compute. “You only get a Jean Kumagai, [email protected] Tel: +1 212 419 7555 Fax: +1 212 419 7570 Samuel K. Moore, [email protected] handful of gates with proteins,” says Alaghi, “and Bureau Palo Alto, Calif.; Tekla S. Perry +1 650 752 6661 stochastic computing could be useful for that.” Tekla S. Perry, [email protected] Philip E. Ross, [email protected] Director, Business Development, David Schneider, [email protected] MEdia & Advertising Mark David, [email protected] Deputy Art Director Brandon Palacio, [email protected] Photography director Randi Klett, [email protected] adt ver ising inquiries Tam Harbert Atssocia e Art Director Erik Vrielink, [email protected] IEEE Globalspec Senior Associate Editor 30 Tech Valley Dr., Suite 102, East Greenbush, NY 12061 Harbert, an IEEE Spectrum contributing Eliza Strickland, [email protected] +1 844 300 3098 Toll-free: +1 800 261 2052 editor, is based near Was hington, D.C. Atssocia e Editors www.globalspec.com For this issue, she interviewed attorney Robyn Celia Gorman (Multimedia), [email protected] VP, Digital Media & Engineering Insight Don Lesem Willie D. Jones (Digital), [email protected] +1 518 238 6514, [email protected] Chatwood about lawsuits over augmented and Michael Koziol, [email protected] VP, sales & Customer Care Peter Hauhuth virtual reality [p. 21]. Harbert explored the Amy Nordrum (News), [email protected] +1 303 594 8007, [email protected] intersection of technology and the law for Spectrum Senior Copy Editor Joseph N. Levine, [email protected] Senior Director, Product Management & Marketing Christian Noe in “The Troubled Life of Patent No. 6,456,841,” C opy Editor Michele Kogon, [email protected] Editorial Researcher Alan Gardner, [email protected] +1 518 238 6611, [email protected] which traced the history of a smartphone patent, Administrative Assistant senior product manager Linda Uslaner and “Supercharging Patent Lawyers With AI,” Ramona L. Foster, [email protected] +1 518 238 6527, [email protected] about the legal startup Lex Machina. Contributing Editors Evan Ackerman, Mark Anderson, John Blau, Robert N. Charette, Peter Fairley, Tam Harbert, R EPRINT SalES +1 212 221 9595, ext. 319 Reprint Permission / Libraries Articles may be Mark Harris, David Kushner, Robert W. Lucky, Prachi Patel, photocopied for private use of patrons. A per-copy fee must Richard Stevenson, Lawrence Ulrich, Paul Wallich be paid to the Copyright Clearance Center, 29 Congress St., Salem, MA 01970. For other copying or republication, Ashok Lahiri Director, Periodicals Production Services Peter Tuohy contact Managing Editor, IEEE Spectrum. Editorial & Web Production Manager Roy Carubia Lahiri’s expertise lies in microscale man- Senior Electronic Layout specialist Bonnie Nani Copyrights and Trademarks IEEE Spectrum is a ufacturing. His group at IBM introduced product manager, digital Shannan Brown registered trademark owned by The Institute of Electrical the first giant magnetoresistive head. At Fo rmFactor, Web Production Coordinator Jacqueline L. Parker and Electronics Engineers Inc. Reflections, Spectral he developed 3D MEMS tools for fabs. And at Enovix, Multimedia Production Specialist Michael Spector Lines, and Technically Speaking are trademarks of IEEE. Atdver ising Production +1 732 562 6334 which Lahiri cofounded in 2007, he’s applied as- Responsibility for the substance of articles rests upon the Atdver ising Production Manager authors, not IEEE, its organizational units, or its members. pects of those technologies to improve lithium- Felicia Spagnoli, [email protected] Articles do not represent official positions of IEEE. Readers ion batteries. He, Nirav Shah, Enovix’s director of senior Advertising Production Coordinator may post comments online; comments may be excerpted for engineering, and Cameron Dales, vice president Nicole Evans Gyimah, [email protected] publication. IEEE reserves the right to reject any advertising. of operations, describe their work in “Building a Safer, Denser Lithium-ion Battery” [p. 34].

IEEE Board of Directors Ctorpora e activities Donna Hourican Zhongsheng Luo President & CEO James A. Jefferies, [email protected] +1 732 562 6330, [email protected] +1 732 562 3928 Fax: +1 732 465 6444 member & geographic Activities Cecelia Jankowski Luo is the applications engineering President-elect José M.F. Moura +1 732 562 5504, [email protected] director at the quantum-dot technology treasurer Joseph V. Lillie Secretary William P. Walsh Standards Activities Konstantinos Karachalios company Nanosys, in Milpitas, Calif. An avid Past President Karen Bartleson +1 732 562 3820, [email protected] Vice Presidents GENERAL COUNSEL & CHIEF COMPLIANCE OFFICER photographer, Luo has the color equivalent of Witold M. Kinsner, Educational Activities; Samir M. El-Ghazaly, Eileen M. Lach, +1 212 705 8990, [email protected] perfect pitch: He can color-calibrate a TV by Publication Services & Products; Martin Bastiaans, Member Educational Activities Jamie Moesch sight, rivaling calibrations made using a meter. & Geographic Activities; Forrest D. “Don” Wright, President, +1 732 562 5514, [email protected] Standards Association; Susan “Kathy” Land, Technical In “Television’s Quantum-Dot Future” [p. 28], Luo Chief Financial Officer & Activities; Sandra “Candy” Robinson, President, IEEE-USA Acting Chief Human Resources officer and his Nanosys colleagues Jesse Manders and Jeff Division Directors Thomas R. Siegert +1 732 562 6843, [email protected] Renuka P. Jindal (I); F.D. “Don” Tan (II); Vijay K. Bhargava (III); Yurek explain why display technologies that use Te chnical Activities Mary Ward-Callan Jennifer T. Bernhard (IV); John W. Walz (V); John Y. Hung (VI); quantum dots have superior color reproduction. +1 732 562 3850, [email protected] Bruno Meyer (VII); Dejan Milojicic (VIII); Alejandro “Alex” Acero Managing Director, IEEE-USA Chris Brantley (IX); Toshio Fukuda (X) +1 202 530 8349, [email protected] Re gion Directors Babak Beheshti (1); Katherine J. Duncan (2); Gregg L. Vaughn (3); Bernard T. Sander (4); Robert C. IEEE Publication Services & Products board Jonas Nilsson Shapiro (5); Kathleen Kramer (6); Maike Luiken (7); Samir M. El-Ghazaly, Chair; John Baillieul, Sergio Benedetto, Gregory T. Byrd, Ian V. “Vaughan” Clarkson, Eddie Custovic, Nilsson is the technical lead for Margaretha A. Eriksson (8); Teófilo Ramos (9); Kukjin Chun (10) Parviz Famouri, Jean-Luc Gaudiot, Ron B. Goldfarb, David functional safety in autonomous Director Emeritus Theodore W. Hissey Alan Grier, Lawrence Hall, Sheila Hemami, Ekram Hossain, drive at Zenuity. With coauthor Erik Coelingh, a W. Clem Karl, Hulya Kirkici, Aleksandar Mastilovic, Carmen S. technology advisor at Zenuity, Nilsson explains IEEE Staff Menoni, Paolo Montuschi, Lloyd A. “Pete” Morley, Mark Nixon, Michael Pecht, Sorel Reisman, Fred Schindler, Gianluca how the company is tackling one of the key executive director & COO Stephen Welby +1 732 502 5400, [email protected] Setti, Gaurav Sharma, Ravi Todi, Yatin Trivedi, H. Joel Trussell, questions about self-driving cars: proving that Chief Information Officer Cherif Amirat Stephanie M. White, Steve Yurkovich, Reza Zoughi an autonomous vehicle is safe [p. 40]. Nilsson +1 732 562 6399, [email protected] sees in these vehicles the potential to change Publications Michael B. Forster IEEE Operations Center +1 732 562 3998, [email protected] 445 Hoes Lane, Box 1331 traffic fundamentally. Besides, he says, “It’s a chief marketing officer Karen L. Hawkins Piscataway, NJ 08854-1331 U.S.A. lot of fun to work with a really difficult problem.” +1 732 562 3964, [email protected] Tel: +1 732 981 0060 Fax: +1 732 981 1721

04 | Mar 2018 | SPECTRUM.IEEE.ORG Invented in the 1800s. Optimized for today.

Visualization of the von Mises stress distribution in the housing of an induction motor by accounting for electromechanical effects.

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comsol.blog/induction-motor SPECTRAL LINES_ 03.18

50,000 60 US $,MILLIONS 57 being generated algorithmicallyMiDAS by IN MiDAS, OPERATION 40,195 50 with no human intervention or review of 40,000 the accusation possible, as was required 34,000 with the legacy system. A comprehensive 85% 40 INCORRECT review later found that MiDAS adjudicated— 30,000 FRAUD by algorithm alone—40,195 cases of fraud, DETER 30 with a staggering 85 percent of the cases MINATIONS 30 22,589 resulting in incorrect fraud determina- 20,000 tions and needless administrative agony 64% 44% CASES INCORRECT 20 for those unfairly accused. REVERSED FRAUD What’s also inexcusable is that, though OR DETER AVERAGE DISMISSED 10,000 MINATIONS PER 64 percent of fraud claims were in the 10 PERSON: process of being reversed or overturned $882 on appeals in administrative3 court, the UIA stubbornly defended MiDASPRE against 0 0 MiDAS CASES OF FRAUD INDIVIDUALS CASES THAT INITIAL COMPENSATION even internal warningsINCREASE INthat something BETWEEN 10/13 AND WRONGFULLY HAD HUMAN PROMISED BY MICHIGAN was wrong with REVENUES,how MiDAS was deter- 8/15 DETERMINED ONLY ACCUSED OF INTERACTION LEGISLATORS TO US $,MILLIONS BY MiDAS ALGORITHM EMPLOYMENT WRONGFULLY ACCUSED mining fraud. However, the public and FRAUD political outcry finally forced the UIA to admit that perhaps there was indeed a significant problem with MiDAS, espe- Robo-Adjudication and Fake Fraud Reports cially its “robo-adjudication” process Michigan’s MiDAS unemployment system falsely and the lack of human review of find- accused thousands of insurance fraud ings of fraud. The UIA decided to cease using MiDAS for purely automated fraud assessment in September 2015. ver 34,000 individuals, wrongly accused of unemployment fraud in While the UIA claims it sympathizes with those Michigan from October 2013 to August 2015, may finally hear if they MiDAS falsely accused of fraud, and has supposedly will receive some well-deserved remuneration for the harsh treat- returned nearly all the fines it had collected, the ment meted out by the Michigan Integrated Data Automated System UIA has also strenuously fought against the class- (MiDAS). Michigan legislators have promised to seek US $30 million action lawsuit brought against it for the personal and in compensation for those falsely accused. ¶ This is miserly, given financial damages those phony accusations created. how many people experienced punishing personal trauma, saw Sources vary on the exact numbers and dollar O their credit and reputations ruined, filed for bankruptcy, had their amounts involved in the MiDAS failings. For further houses foreclosed on, or were made homeless. A sum closer to $100 million, information, you can find many excellent articles as some are advocating, is probably warranted. ¶ The fiasco is all too familiar: on the goings-on in the Detroit Metro Times. A government agency wants to replace a legacy IT system to gain cost and Given that the UIA stonewalled attempts to discover operational efficiencies, but alas, the effort goes horribly wrong because of the depth, breadth, and reasons behind the fraudu- gross risk mismanagement. ¶ This time, it was the Michigan Unemployment lent fraud accusations, the court ruling may be legally Insurance Agency (UIA), which wanted to replace a 30-year-old mainframe correct, but it is morally ludicrous. The ruling, which system running Cobol. After spending $44,400,558 and 26 months on the is being appealed to Michigan’s Supreme Court, so effort, the UIA launched MiDAS. The UIA soon proclaimed it a huge success, shamed the state’s legislators and governor that they not only in coming in under budget and on time but in uncovering a large agreed to changes to the state’s unemployment law number of previously missed fraudulent unemployment filings. ¶ For instance, and, at least in principle, to the creation of a MiDAS soon after MiDAS was put into operation, the number of persons suspected victim compensation fund. We’ll soon see whether one

of unemployment fraud grew fivefold in comparison to the average number is actually ever created. —Robert N. Charette Press Free etroit D found using the old system. The newfound fraud generated huge amounts of money for the UIA. ¶ While the UIA was patting itself on the back for a An extended version of this article appears online as ted Press; Press; ted job well done, unemployment lawyers and advocates noticed a huge spike “Michigan’s MiDAS Unemployment System: Algorithm a in appeals by those accused of fraud. In case after case, the accusations of Alchemy Created Lead, Not Gold.” fraud were subsequently thrown out on appeal. Digging deeper, the lawyers

and advocates discovered that a large number of fraud accusations were ↗ Post your comments at https://spectrum.ieee.org/spectrallines0318 Associ sources:

06 | Mar 2018 | SPECTRUM.IEEE.ORG 5,000: Number of photos digital artists USED to produce a bronze replica of an oak tree

The Iraqi city of Mosul is HOLD STILL: Artists scan a still recovering from its lamassu at night in the Ancient Statues, British Museum. brutal occupation by the Islamic State. The city suffered devastat- Digitally ing bloodshed during that time, and many archaic statues and artifacts were destroyed by militants and vandals. Raising the

onservation city from the rubble will be rough work. In at least a couple of C Reconstructed, instances, though, resurrecting a piece of the ancient past will come courtesy of a 3D scanner. Later this month, two ultradetailed facsimiles of the massive echnology in in echnology Return to Mosul T stone statues known as lamassu, protective spirits that date igital igital

D British Museum hangs onto originals back nearly 3,000 years to the Assyrian empire, will begin or or f (and the copyright) a journey from the Netherlands to take up permanent resi- dence in Mosul. As products of the digital age, their journey poses questions about authenticity and where objects belong. These new spirits are copies of two lamassu originally exca-

Factum Foundation Foundation Factum vated by a British archaeological expedition in the mid-19th

SPECTRUM.IEEE.ORG | Mar 2018 | 07 Petit contacted Lowe, and work finally resumed in 2016. Factum Arte used the data from the old scans to control a mill- ing machine that carved a dense poly- urethane solid into the shape of each lamassu. The studio then used these models to make silicon molds in sec- tions for the sculptures. Using color swatches and close-up images, Lowe painstakingly matched the pigment colors to the original Assyrian gypsum. Factum Arte’s Sebas Beyro mixed the pigments into scagliola, a kind of tinted plaster dough, which he pressed into silicon molds to create the facsimiles. As the Nineveh exhibit opened last Octo- ber, Lowe, Petit, and officials at the British Museum—which holds the copyright for the facsimiles—began talking with antiquities authorities in Iraq. During the Mosul occupation, the Islamic State made a spec- tacle of smashing Assyrian artifacts. With the Islamic State now gone from Mosul, the (2)

exhibit’s organizers decided to send the ion t va replicas of the lamassu to Iraq. (The Brit- r

ish Museum will hold on to the originals.) onse C

PAST TO PRESENT: Adam Lowe of Factum and shards. For the lamassu, they used Faisal Jeber, director of the Gilgamesh in ogy Arte matches the color of a replica to that of a white-light scanner built by the com- Center for Antiquities and Heritage Pro- l an original lamassu [bottom left]. Two replicas pany NUB3D. tection, is eager for the facsimiles to arrive.

now stand in an exhibition ending this month in Techno l a the Netherlands [top]. The studio mounted its scanners to a “Lamassu have become an icon of the t Digi

tripod close to each lamassu. The scan- Mosul resurrection post-ISIS,” he says. r

ners projected parallel lines on the sur- Having fled Mosul the week after the fo ion t a century. While charting Mesopotamia, face. A sensor measured the deformation occupation began, Jeber returned in late d oun

the group uncovered a field of artifacts that appeared in the lines as they moved 2017 with a militia battling to take the city F

um that had been buried for 2,700 years. slowly over the 4-meter-tall sculptures, back from the Islamic State. The city’s t ac F The lamassu they found there—impos- generating a cloud of millions of data east bank is slowly returning to normal, : om ing winged statues—once stood guard points along the x, y, and z axes. he says, while the west bank, which is tt o B along the walls surrounding the ancient Factum Arte’s work with these lamassu still 60 to 80 percent destroyed, tries to ; ies t city of Nineveh, near what is now Mosul. remains among the highest-resolution 3D reinstate basic services, such as water iqui t n

The excavators brought two of the stat- scans ever of objects that size. But the and electricity. A ues back to London. traveling exhibition they were intended The University of Mosul’s director of of

In 2004, the art historian Adam for was derailed by financing shortfalls Assyrian studies, Ali Y. Aljuboori, says useum M

Lowe set out to record these statues at and the escalating Iraq war. he will have mixed feelings when the l iona t facsimiles arrive. “I’ll be excited. There a 300-micrometer resolution in order to The replicas were never cast, but the N

ch produce copies of them for a traveling data from the scans remained. Then, are no complete figures left in Mosul t exhibition. Lowe heads Factum Arte, an four years ago, curator Lucas Petit of now,” Aljuboori says. “But the spirit art studio that has made a stir by casting the National Museum of Antiquities, in of the Assyrian artists who made the Looman/Du precise facsimiles of antiquities. the Netherlands, began organizing a originals? That we have lost forever.” -Jan

For five weeks, Lowe and his team spent marquee exhibition about Nineveh. He —Michael Dumiak rt every evening at the British Museum wanted the facsimiles to be its touch- ↗ Post your comments at http://spectrum.ieee.org/ scanning the lamassu and relief panels stone pieces. digitalartifacts0318 Robbe Top:

08 | Mar 2018 | SPECTRUM.IEEE.ORG tortion occurs when two signals having different frequencies combine to produce Reverse Engineering synthetic signals at the difference, sum, or multiples of the original frequencies. When signal processing equipment the “Sonic Weapon” behaves in a nonlinear way, it can cause this type of distortion. For example, Fu Researchers say bad engineering, not a deliberate attack, says, microphone circuitry can exhibit may be to blame at the U.S. embassy in Cuba nonlinear behavior, and waves propa- gating through air can also behave in a Last August, reports emerged that U.S. and Canadian nonlinear fashion. “As acoustic waves diplomats in Cuba had suffered a host of mysterious ail- containing multiple frequencies travel ments. Speculation soon arose that a high-frequency sonic through a nonlinear system, you can weapon was to blame. Acoustics experts, however, were get these bizarre ripples in the spec- quick to point out the unlikeliness of such an attack. Among other trum of the signal,” he explains. “At things, ultrasonic frequencies—from 20 to 200 kilohertz—don’t propa- the same time, intermodulation dis- gate well in air and don’t cause the ear pain, headache, dizziness, and tortion can produce lower-frequency other symptoms reported in Cuba. Also, some victims recalled hear- signals than the original signals. In ing high-pitched sounds, whereas ultrasound is inaudible to humans. other words, inaudible ultrasonic waves The mystery deepened in October, when the Associated Press (AP) going through air can produce audible released a 6-second audio clip, reportedly a recording of what U.S. by-products.” embassy staff heard. The chirping tones, centered around 7 kHz, were Yan followed up the simulations with indeed audible, but they didn’t suggest any kind of weapon. lab experiments, in which he used two Looking at a spectral plot of the clip on YouTube, Kevin Fu, a computer ultrasonic speakers, one emitting a sig- scientist at the University of Michigan, noted some unusual ripples. He nal at 25 kHz and the other at 32 kHz. thought he might know what they meant. When he crossed the two signals, it pro- Fu’s lab specializes in analyzing the cybersecurity of devices connected duced the telltale high-pitched sound to the Internet of Things, such as sensors, pacemakers, RFIDs, and auton- at 7 kHz, which was equal to the differ- omous vehicles. That work has taught him that modern electronics often ence between the two speakers’ frequen- behave in unpredictable ways and that such devices can be manipulated— cies—and the same frequency as in the intentionally or inadvertently—using carefully crafted acoustic or radio AP audio. In a nod to the Internet meme interference. To Fu, the ripples in the spectral readout suggested some “rickrolling,” Yan was even able to embed kind of interference. an ultrasonic version of the Rick Astley He discussed the AP clip with his frequent collaborator, Wenyuan Xu, a professor at Zhejiang University, in Hangzhou, China, and her Ph.D. student Chen Yan. “We saw it as an interesting puzzle,” says Xu, whose lab works on embedded security, including the use of ultrasound and radio waves to fool voice-recognition systems and self-driving cars. “It was a lot of fun to try to solve it.” “I thought it might be subharmonics,” Fu recalls. “But a week later, Chen said, ‘No, Kevin, you’re wrong, and I just did an experiment to prove it.’ ” Yan and Xu started with a fast Fourier transform of the AP audio, which revealed the signal’s exact frequencies and amplitudes. Then, through a series of simulations, Yan euters R showed that an effect known as intermodulation distortion could have produced the AP sound. Intermodulation dis-

SONIC MYSTERY: At least 24 employees of the U.S. embassy in Cuba ndre Meneghini/ ndre a heard high-pitched sounds between December 2016 and August 2017,

Alex and suffered injuries thought to be related to the noise.

news

SPECTRUM.IEEE.ORG | Mar 2018 | 09 song “Never Gonna Give You duced the wide range of symp- Up,” which became audible at toms, including brain damage, Ferroelectric the point where the two sig- that afflicted embassy work- nals crossed. ers. “We know that audible Transistors: Having reverse engineered signals can cause pain, but the AP audio, Fu, Xu, and Yan we didn’t look at the physio- then considered what combi- logical effects beyond that,” The Ultralow- nation of things might have Fu says. At press time, the caused the sound at the U.S. FBI had yet to announce the Power Solution? embassy in Cuba. “If ultra- results of its investigation. sound is to blame, then a A panel of Cuban scientists and medical doctors, mean- Doubts linger over their ability to likely cause was two ultra- jump from lab to fab sonic signals that acciden- while, concluded that a “col- tally interfered with each lective psychogenic disorder” other, creating an audible brought on by stress may have Academics have high hopes for ferro- side effect,” Fu says. There been at work. electric materials. Adding a single layer are existing sources of ultra- Fadel Adib, a professor at of these materials, which have unusual sound in office environments, MIT who specializes in wire- electrical properties, to today’s transis- such as room-occupancy sen- less technology for sensing tors could radically decrease the power consump- sors [see, for example, this and communications, calls tion of chips. month’s Back Story]. “Maybe the study by Fu and his col- But as engineers presented the latest research there was also an ultrasonic leagues “a creative take on on ferroelectrics at the IEEE International Elec- jammer in the room and an what might have happened.” tron Devices Meeting (IEDM), in San Francisco in ultrasonic transmitter,” he Adib, who wasn’t involved in December, the mood in the room fluctuated between suggests. “Each device might the research but reviewed the excitement and doubt. have been placed there by a results, adds that wireless sig- Many in industry are skeptical about the benefits different party, completely nals can and do interact with of ferroelectrics. Still, the IEDM meeting made it unaware of the other.” one another. “And if that hap- clear that semiconductor companies are now pay- One thing the investigation pens, you’ll hear signals you ing attention. Researchers from GlobalFoundries didn’t explore was whether wouldn’t expect to hear,” he presented data on the performance of ferroelectric- the AP audio could have pro- says. “Given all the possible frosted transistors made using their 14-nanometer explanations, this defi- manufacturing technology. nitely seems the most The magic of ferroelectrics is their potential plausible and the most to free engineers from the “Boltzmann tyranny,” “Given all technically feasible.” named for Ludwig Boltzmann, who did foun- Fu is careful to offer a dational work in thermodynamics, says Aaron the possible caveat: “Of course, we Franklin, an electrical engineer at Duke University, don’t know for certain in North Carolina. To boost the current through explanations, this was the cause. But a traditional field-effect transistor by a factor of bad engineering just 10 at room temperature, engineers must apply this definitely seems much more likely at least 60 millivolts. This sets a lower limit on seems the than a sonic weapon.” transistors’ power consumption, which engineers —Jean Kumagai dream of limbo-ing under. Getting a strong signal most plausible at lower voltages would save power and enable Editor’s note: An article longer battery lives. and the most by Kevin Fu, Wenyuan Operating at lower voltages will be necessary for Xu, and Chen Yan about engineers to further shrink transistors. As they get technically their research will be smaller, they do a worse job of shedding heat. Shrink feasible” published in March at them too much and the overheating transistors will http://spectrum.ieee.org/ melt. Running transistors at lower voltages keeps —Fadel Adib, MIT cubasonicweapon0318 ■ temperatures in check.

10 | Mar 2018 | SPECTRUM.IEEE.ORG Gate from experimental ferroelectric devices tend to be “all over the place,” he says. If Source Drain researchers don’t take careful note of the buildup of charges in the ferroelectric and the semiconductor, making sure they are very closely attuned—a property called capacitance matching—the devices will not Insulator work. Krivokapic says poorly fashioned devices have produced poor results, and caused engineers to underestimate the potential of ferroelectrics. To overcome the speed problem, the Ferroelectric layer GlobalFoundries team chose a ferroelec- Silicon substrate tric material that does not require ions or atoms to relocate. In their experimental 14-nm transistors, Krivokapic says, clouds of electrons around silicon-doped hafnium POWER DOWN: Chipmakers are adding a only knew of ferroelectrics that contained dioxide experience the polarization. And thin layer of ferroelectric material to transistors, lead and other nasty materials, and the electrons can move fast: Ring oscillators including fin-shaped field-effect transistors (FinFETs), to reduce the gate voltage required ferroelectric layer had to be very thick,” made with these transistors can switch at for switching. says Franklin. More recently, researchers the same frequency as those made with the have figured out how to encourage friend- usual recipe, yet they require just 54 mV to Ferroelectric materials are defined by lier materials, such as hafnium dioxide, achieve a tenfold increase in the current. their tendency to experience profound already used in chip components, to act Franklin says it’s difficult to pin down a electrical polarization in response to rela- as ferroelectrics. Instead of using these theoretical minimum, since designs vary. tively puny electrical fields. Put a voltage materials to replace insulators, as Datta However, ferroelectric devices typically across a ferroelectric film and charges— had proposed, engineers typically layer don’t go below 30 mV—although some sometimes charged atoms—within it will them on top of existing insulators. researchers have reported devices that quickly move from one side to the other. Even so, problems remain. The strange switch at 5 mV. “You put half a volt on it, and because of behavior of electrical charges in ferro- GlobalFoundries’ devices require a 3- to the polarization it’s like applying a whole electric materials slows things down—it 8-nm-thick layer of ferroelectric material, volt,” says Franklin. takes time for charges to relocate. Some which is still relatively thick. But research- Most of the ways around the Boltzmann researchers have predicted that transis- ers are excited about this first practical tyranny require ditching traditional tran- tors built with ferroelectrics will never demonstration. “This is not something sistor designs altogether. Compared exceed 100 megahertz. And some think from an academic lab, where you can argue with those, the ferroelectric approach that building these devices will require that it’s not CMOS compatible,” says elec- should be pretty straightforward. All very thick layers of ferroelectrics—too trical engineer Deji Akinwande, of the Uni- the industry needs to do is add a ferro- thick to be practical. versity of Texas at Austin. “This field seems electric layer. “It’s such a simple modi- At IEDM, after a presenter described to be rapidly maturing to the point where fication,” says Franklin, who cochaired how ferroelectrics could help engineers even the big companies are working on it.” the IEDM session. scale chips down to 2 nm, an audience These devices are not yet ready for This idea was first proposed in 2008. member pointed out that the proposed production, says Michael Chudzik, a That year, Sayeef Salahuddin, now a designs did not leave enough physi- senior director at semiconductor equip- professor at the University of Califor- cal space for a ferroelectric layer thick ment maker Applied Materials, but nia, Berkeley, and his Purdue University enough to provide the predicted benefits. they do show that ferroelectrics are Ph.D. advisor Supriyo Datta published an The presenter, looking a bit flummoxed, under serious consideration. In the influential paper showing that replacing replied that the work was theoretical. semiconductor industry, he says, “you a traditional insulator with a ferroelec- Zoran Krivokapic, an electrical engineer have to shoot ahead to actually hit it.” tric one should lead to power savings. who leads GlobalFoundries’ ferroelectrics —Katherine Bourzac The idea didn’t gain much traction at project, says there are misunderstandings ↗ Post your comments at http://spectrum.ieee.org/ the time. “It seemed crazy because we about what ferroelectrics can do. Data ferroelectrics0318

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illustration by Emily Cooper SPECTRUM.IEEE.ORG | Mar 2018 | 11 news

India’s Biometric IDS Trigger Privacy Lawsuits The nation’s Supreme Court weighs in

In January, justices of the Su- world’s most ambitious government ID, PLEASE: A citizen presents an identification preme Court of India gathered identification program. Aadhaar’s reach card with his Aadhaar number, which is linked to 10 fingerprints, two iris scans, and a photograph. to discuss the country’s national iden- and ubiquity has made it a tempting vehi- tification system, called Aadhaar. Since cle for centralizing activity, including izens who could not obtain a card from 2010, authorities have enrolled 1.19 billion welfare payments and mobile number corrupt local officials, and members of s

residents, or about 93 percent of India’s registrations. But it has also raised major families whose heads of household did e g population, in the system, which ties fin- privacy and security issues. not share benefits with them. Individu- gerprints, iris scans, and photos of Indian The Indian government’s original argu- als, rather than households, now have /Getty Ima /Getty FP

citizens to a unique 12-digit number. ment for Aadhaar was to replace paper Aadhaar numbers, and obtaining one is A Almost a decade later, India is still ration cards for food entitlements [see free at any enrollment office in the country. grappling with the technical, legal, “India’s Big Bet on Identity,” IEEE Spectrum, In the years since the program began,

and social challenges of launching the March 2012]. The old system excluded cit- banks, mobile operators, and the govern- Seelam/ Noah

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12 | Mar 2018 | SPECTRUM.IEEE.ORG ment itself have started to require Aadhaar and Regulations, these problems will keep sensitive data, they are paying more authentication to access services, even cropping up in new ways,” Panday says. attention to mishaps. “Because the con- though India’s Supreme Court has found The government’s relentless push to stituency has changed,” Khera says, “pub- that the government cannot force citizens expand Aadhaar may be turning influ- lic opinion has changed dramatically.” to use Aadhaar to obtain entitlements. ential Indians against the program, says —Lucas Laursen The case now before the country’s Khera. Now that India’s middle class is ↗ Post your comments at http://spectrum.ieee.org/ highest court, which was ongoing at being asked to link their Aadhaar to aadhaarid0318 press time, combines almost three dozen petitions arguing that Aadhaar violates a constitutional right to privacy and interferes with access to entitlements. New Version! While some of the petitions challenge the entire Aadhaar Act, others focus on a government requirement to use Aadhaar to verify applicants for new SIM cards or to link Aadhaar to tax IDs. In practice, an Aadhaar number is like a telephone number: Nobody forces you to have one, but doing anything without one is almost impossible. As Aadhaar has grown, the program has also proven susceptible to fraud. In January, The (Chandigarh) Tribune reported that village-level Aadhaar enrollment agents were selling access to personal details for as little as US $8. The ability of third parties to compile such data in a central repository may be one of the weaknesses of the Aadhaar system. Days later, the Unique Identifi- cation Authority of India (UIDAI) said it would offer facial recognition along with user-generated virtual ID numbers to verify personal identities, so users would not have to reveal their Aadhaar numbers for every transaction. When things go wrong, Aadhaar hold- ers have limited recourse. “Individuals can’t go to police to complain about com- promised data, because only UIDAI can do so” under present law, says economist Reetika Khera, of the Indian Institute of Over 75 New Features & Apps in Origin 2018! Technology, in New Delhi, who has stud- For a FREE 60-day Over 500,000 registered users worldwide in: ied Aadhaar’s social impact. evaluation, go to ◾ 6,000+ Companies including 20+ Fortune Global 500 OriginLab.Com/demo Many of Aadhaar’s legal and social prob- ◾ 6,500+ Colleges & Universities and enter code: 8547 lems have their roots in incomplete tech- ◾ 3,000+ Government Agencies & Research Labs nical regulations, says Jyoti Panday, Asia Policy Fellow at the Electronic Frontier Foundation, in New Delhi. “Until there 25+ years serving the scientific & engineering community is strict enforcement of the standards for collection, storage, and use of biometric data as established under the Aadhaar Act

SPECTRUM.IEEE.ORG | Mar 2018 | 13 14 | Mar 2018 | SPECTRUM.IEEE.ORG photograph by Boris Horvat/AFP/Getty Images DIVER DRONE SHOOTS SEA SCENES

drones have moved from the skies to the seas, giving divers and oceanographers a new tool for capturing images of the wonders beneath the surface. Here, a diver is shadowed by a prototype autonomous drone called iBubble that’s in “follow me” mode. The unit uses echolocation and object recognition to avoid obstacles while tracking moving objects such as fish. A domed compartment at the front of the unit holds a GoPro camera. To ensure high-quality images, the iBubble has an image- stabilization system and twin 1,000-lumen lights. The diver can start and stop recording and switch between camera modes using a wrist- worn remote control. The iBubble can reach depths of 60 meters and run for an hour on its two 8-ampere-hour lithium- ion polymer batteries; when they’re depleted, the drone is designed to resurface automatically.

THETHE BIG BIG PICTUREPICTURE newsnews

SPECTRUM.IEEE.ORG | Mar 2018 | 15 Japan New Ideas Start Here

Japan fires imagination like few other countries in the world. Its achievements in science, art and industry – a reflection of the talents and aspirations of its people – have created a society that balances tradition and innovation, nature and technology in truly remarkable ways. JNTO’s Website Enhancements A visit to Japan is an opportunity to discover a for Meeting and Event Planners universe of new ideas. Its tourism infrastructure is very well developed, making it a breeze for JNTO’s Website was upgraded: groups to travel around to enjoy all that the country has to offer. With strong support from • Enhanced information regarding corporate local convention bureaus, overseas meeting meetings, incentive trips, and conferences in planners are also able to plan fun group Japan activities or excursions to special interest • The easy-to-use planning tool for venue and facilities that are not normally open to the facility searches casual tourist. • An extended list of suppliers to help you To highlight Japan’s advantages as an organize your event innovative and exciting meetings and events destination, Japan has adopted the tag line: New ideas start here. Japan’s unique culture and advanced technology, together with the opportunity for interaction with the Japanese academic, business, and industrial community, inspire participants and offer new perspectives and insight that propel the further evolution of Japan National Tourism Organization science and industry. Headquarters Tokyo, Japan Email: [email protected] With this tag line, the message is clear: coming www.japanmeetings.org to Japan brings visitors into contact with the imagination and intelligence of Japan’s people JCB New York and culture, which underpins the country’s high Alicia Hinds quality, technological expertise, and creativity, Convention Specialist Tel: +1-212-757-5640 holding meetings and events in Japan enables Fax: +1-212-307-6754 participants to gain inspiration and flashes of Email: [email protected] insight that enable future business growth. www.us.jnto.go.jp ADVERTISING An interview with Professor Gordon McBean, President of ICSU What do you think about the actual status of scientific research in Japan, within and outside of your own field of experience? Japan’s science is very good. And I mean, when we are putting together international scientific programs or projects, we try and bring together a team of scientists from around the world with an appropriate distribution by geography, by discipline, by gender, by age, those kind of factors. But if, as president of the International Council for Science, I receive a list of 20 members for a science project and there was not a Japanese one on it, I would question why not? I think the Japanese science community is very strong, in the fields I work in, climate change and particularly disaster risk reduction, the strength of understanding and know-hows, not only a combination of engineering science and technology, but also Prof. Gordon McBean importantly the physical natural sciences of weather systems, ocean currents, flooding, President, International Council for Science tsunamis and also the social issues, the cultural issues. One of the biggest problems we’re seeing in unfortunate severe weather events is what we call: risk interpretation to action. If people hear a warning, do they know what to do? Do they understand? Do they respond in a way that reduces the impact on them and their children? So it is very important and we see here studies of this and scientists who have been working on this kind of issues in Japan, and other countries, but bringing them together is really important.

XXIII World Congress of Neurology - WCN 2017 The XXIII World Congress of Neurology (WCN 2017) took place in Kyoto, Japan on September 16 – 21 2017, co hosted by the Japanese Society of Neurology and Asian and Oceanian Association of Neurology. This year’s theme was “Defining the Future of Neurology”.

WCN brought together leading scientists, public health experts, policy-makers to translate recent momentous scientific advances into action that will address means to end the epidemic, within the current context of significant global economic challenges. Kyoto International Conference Center

During the long period of preparation for this convention, how did you feel about Japan’s teamwork? Japan is fantastic. I’m not saying this in any way to flatter the Japanese but, they work as a team and the teamwork is meticulous and detailed. The attention to excellence is very impressive and very noticeable. When Japan won the bid, 4 Guests visiting DAIGOJI Temple. years ago, I was delighted in many ways because I said the Japanese will do everything for us. Prof. Raad Shakir They showed a lot of promise and understanding President, World Federation that they will suggest something to you in a very of Neurology polite and in the Japanese way. We respect that. And we have to learn as well that when we come to Japan, when we try to do any activities, whether it’s social activities, trying to get food, or trying to get transport, there is a certain Japanese way of doing it. This is efficient but we are not used to doing it this way, like the rest of the world. So, we have to learn how to live with that and once you know how it works, it’s fantastic. Working as a team is excellent and the Japanese side in neurology is a very highly sophisticated, organized, scientifically advanced team and we have absolutely no problem working with them. Best New Journal in STM 2015 Become a published author in 4 to 6 weeks.

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IEEE 696-1983

The Altair’s S-100 internal bus design became an IEEE standard, retired in 1994

The Altair, Reincar- nated An Arduino- based kit resources_HANDS ON takes you

he MITS Altair 8800 was the first commercially successful personal computer. back T Created by Ed Roberts in 1974, it was purchased by the thousands via mail order, proving there to 1974 was a huge demand for computers outside universities and large corporations. Its influence was immense: For example, after seeing the Altair featured on the cover of the January 1975 issue of Popular Electronics, Bill Gates and Paul Allen founded Microsoft (then Micro-Soft) in order to write a Basic interpreter for the new machine. • The Altair sold for US $439 in kit form. Original machines are now collectors’ items that trade for thousands of dollars. Fortunately, there are some cheaper alternatives for people who want to get a direct understanding of the Altair computing experience. Modern kits that replicate the Altair hardware as faithfully as possible are available, as are purely virtual online simulators. Falling somewhere between a replica and a simulation is the $149 Altairduino kit from Chris Davis. The Altairduino duplicates the front panel of the Altair in all its LED- and switch-festooned glory while emulating the internal hardware (including some once fantastically expensive peripherals), using an Arduino Due. • The Altairduino is derived from David Hansel’s work on cloning the Altair with the Arduino Due and Arduino Mega 2560. If you want to build one of Hansel’s designs from scratch, you can do so by following his free instructions on hackster.io. The advantage of Davis’s kit is that it provides all the components, including a nice bamboo case and plastic front panel, along with a custom printed circuit board (PCB) that greatly simplifies

Randi Klett Randi construction. • The original Altair’s relatively large size means that most of the components are fairly well spaced out on the PCB. Even a beginner

SPECTRUM.IEEE.ORG | Mar 2018 | 19 could do much of the soldering, functions to save a little memory), although a little bit more experi- or its more advanced 16-KB ence is required for trickier areas, Basic. The latter has a number of such as the headers that connect programs you can load from the to the Due. The fiddliest bit is add- Altairduino’s memory, including ing the LED indicator lights. These early computer game classics are mounted on spacers, and such as Lunar Lander, Star Trek, it’s best to put the front panel in and Hunt the Wumpus. place to ensure alignment, which You can put additional Altair soft- can put you in one of those situ- ware on a microSD card, which you ations where you really wish you plug into a reader that’s soldered had an extra pair of hands to hold to the PCB (Davis conveniently of- the panel, LED, and PCB tightly to- fers a one-stop bundle on his web- gether while you solder. The online site). Once the kit is assembled, you instructions are detailed and well can’t access the reader to swap illustrated, but I would recommend out the card without unscrewing skipping forward and making sure the case, but since the universe of you solder all the resistors in the kit Altair 8800 software isn’t growing before proceeding to add other, that rapidly, I’ll manage. (That said, taller, components. I did just see someone announce The Altairduino improves on they had gotten a Forth compiler the original Altair in two impor- running on the Altairduino that I’d tant respects. First, it offers mod- like to try.) ern interface options. You can The card reader emulates the connect an old-school terminal 88-HDSK hard disk that was avail- using an optional DB-9 connec- able in the business version of the tor (which I will stipulate should Altair, which sold in the late 1970s properly be called a DE-9 con- for $11,450 to $15,950. A num- nector, so no need to send me ber of disk images are available letters this time!), but you can in the software bundle, includ- also use a soft terminal running ing one with the CP/M operating on a computer via a USB connec- system. The CP/M software also tion, or even Bluetooth. comes with a bunch of software, You do the initial configura- including parts 1, 2, and 3 of Zork, tion of the Altairduino via USB. a pioneering text adventure game. The instructions are written for The Altairduino is a lovely kit Microsoft Windows, so I had to that’s an enormous amount do a little poking around the fo- of fun—it is surprisingly satis- rums on the Altairduino site to fying to control a computer by figure out how to get my Mac to talk to the Lights, switches, action: A printed circuit flipping switches versus, say, mouse clicks. USB interface. Setting the baud rate to board contains additional circuitry for driving LEDs More seriously, simply looking at pictures of [top], but most of the work is handed off to an Arduino 115200 when launching the “screen” termi- Due plugged into a rear connector [middle]. The early personal computers, with their blinking nal command did the trick, and once I set the finished PCB [bottom] is mounted in the case. rows of lights and bulky cases, can leave the Bluetooth connection up as the power‑on impression they were little more than toys. But default, it was all smooth sailing. engaging with this incarnation quickly dem- The second big improvement is that the onstrates that the Altair was a capable system, Altairduino comes loaded with a lot of soft- and it becomes much clearer why it was that ware. You can call up some programs purely called up with a combination of switch throws this machine came to be so critical in estab-

by flipping various front panel switches, such and terminal commands. You can quickly fire lishing the value of personal computing. ) (3 as Kill the Bit, a game that hacked the Altair’s up Microsoft’s very first 4-kilobyte Basic —Stephen Cass ss memory-address indicator lights to act as a (which gives you the option, on startup, to dis- ↗ Post your comments at https://spectrum.ieee.org/

1-dimensional display. Other programs are able its sine, random number, and square root altairduino0318 Stephen Ca

20 | Mar 2018 | SPECTRUM.IEEE.ORG RESOURCES_AT WORK

this technology and make sure that their The Legal Hazards of companies sort out who owns what in the VR and AR terms and conditions.

The lawS around such T.H.: What about dangers to users? apps ARE still fuzzy R.C.: This technology can be used to help people in many ways. For example, there’s an app called Fearless that was created by a fellow trying to overcome his phobia of spiders. Because VR is so realistic, you can have a process in which you gradually immerse yourself in things. But the fact that [VR] feels so real can also be used for evil. In late 2016, for example, a woman playing a multiplayer virtual reality game called QuiVr experienced what she says felt like a real sexual assault. During the game, someone came up to her, tried to rub her chest, and chased her when she tried to get away. Because VR seems so real and evokes real emotions, she felt just as violated as though she had been assault ed in real life. However, there are no laws that say sexual assault in VR is the same as being sexually assaulted in the real world. Think about potential risks like this. Is there a potential for someone to be harmed? What s virtual- and augmented- The second category is virtual-IP rights might you embed into the product that miti A reality technologies mature, legal in the real world. For example, I design an gates or eliminates these risks? Perhaps questions are emerging that could app that geotags a building, and when I view you include a function that allows one user trip up VR and AR developers. One of the first the building through my smartphone, the to block another user, or give them a way lawyers to explore these questions is Robyn app augments that view with information to create a safe space that prevents others Chatwood, of the international law firm about the building, such as height, number from coming closer than 1 meter without Dentons. “VR and AR are areas where the of tenants, etc. Who owns the rights when your permission. law is just not keeping up with [t echnology] you overlay information virtually onto a real There are also issues of privacy and secu- developments,” she says. IEEE Spectrum physical object? At the moment, there are rity. What data are you collecting? Is that data contributing editor Tam Harbert talked with no effective laws on who owns such rights. available to others? For example, are the lo- Chatwood about the legal challenges. Owners of landmark buildings might want to cations of users beaconed to others? Could own those rights, but today they can’t control others determine whether a particular user is Tam Harbert: What critical legal issues who presents information about their build- female, or a child? Could your product unwit- do engineers need to know about? ings in an augmented-reality application. tingly facilitate a dangerous situation? The other thing is an issue that’s normally Robyn Chatwood: IP rights are the most sorted out by contract, but I still consider T.H.: When will these legal issues be important. In VR, IP rights come in two cat- it a gray area. Users can design and build sorted out? es g egories: real-world-IP rights in the virtual things virtually. Say someone comes up ma I world and virtual-IP rights in the real world. with a really incredible and exciting design R.C.: I think within 5 to 10 years there may be To give you an example of the first category, for a building or a city. Who owns the rights an incident that draws a lot of attention to a McDonald’s has trademarks on its brand in to that design? That is normally spelled out particular problem. Or adoption may just be- ia/Corbis/Getty ia/Corbis/Getty c the real world. But what if someone depicts in the terms and conditions users are re- come so widespread that society recognizes a McDonald’s burger or restaurant in a virtual quired to sign, but it becomes more im- the need for regulations. world? Does trademark registration stretch portant with VR content. Engineers should

Joan Cros Gar Cros Joan to cover everything in a virtual world? think through what people might do with ↗ Post your comments at https://spectrum.ieee.org/vrlaw0318

SPECTRUM.IEEE.ORG | Mar 2018 | 21 RESOURCES_TOOLS & TOYS

The Weird and the Wonderful From CES Autonomous luggage, a machine for folding clothes, and more

n January, editors from IEEE PDA, a product category long since I Spectrum hit the show floor at CES swallowed up by smartphones. Sec- in Las Vegas. The show is perhaps ond, it has a clamshell design, an best known for the gadgets that are unveiled approach largely discarded in the each year by hopeful manufacturers. And while touch-screen era. But the Gemini has some people like to sneer at gadgets as the proved surprisingly popular among trivial amusements of a decadent society, many a certain set of techies who like it for technologies that later came to be considered two main reasons: They want to be essential parts of modern life began their life able to use a real keyboard without as unnecessary technical baubles. For exam- having to carry a separate item, and ple, in 1970, the first consumer VCR prototype they also appreciate that the PDA can was unveiled at CES, a technology previously dual boot into either Android or Linux, needed only by television studios. which lets them use it as an actual So I defend the gadget as a worthy ob- computer, not just a locked-down ject of inquiry and consequently spent a fair interface for apps or websites. The amount of my time at CES looking for inter- Gemini was wildly popular when it esting examples, particularly from smaller launched on Indiegogo, and it will go companies and startups. Here are my per- on sale to the general public at $500 sonal nominations for this year’s weird and for a Wi-Fi only version and $600 for wonderful, in no particular order. a 4G-enabled version.

Hushme FoldiMate Winner of the “gadget that looks most like The FoldiMate is a refrigerator- a prop from a dystopian science fiction mov- size machine that folds clothes. And ie” award, the Hushme is designed to solve a that’s it. But it was enough to make it— problem endemic to today’s crowded spaces by far—the most popular item I tweeted about tire subgenre of science fiction. The lithium- and open offices—having to listen to people’s at CES, with opinion running toward the “shut battery-powered Prosthesis was built by the phone conversations (or conversely, having up and take my money” point of view, although robotics division of Furrion and is intended other people eavesdropping on your private a significant fraction of responders thought it to explore the potential of exoskeleton tech- conversation). The Hushme is an earphone- the ultimate in laziness. The version demoed nology (think the power loader seen in Aliens).

; ; s equipped mask that you snap around your at the show was a partially working prototype, Furrion hopes that Prosthesis could be used e g ma I mouth. A microphone inside the mask trans- but the FoldiMate crew hopes to start ship- as the basis for a mech racing league, which y mits your voice to your phone, while the ping units in late 2019 for $980. will sound either utterly awesome or utterly tt /Ge P F ss mask blocks the sound of your voice from insane to you, depending on your taste in sci- A / Ca being overheard by those nearby. It’s going Prosthesis ence fiction. So this last entry is up to you: ew McN

ephen t into mass production in April, but you can Okay, this last one is stretching the defini- Do you think this was the best gadget at CES, d S ; s e

preorder it now for US $179. tion of “gadget” to the breaking point, but or the craziest? —Stephen Cass Davi ; g ss ma I

it is still a device intended to be used by y Gemini PDA an individual, and it was on the CES show An extended version of this article appears in tt /Ge ephen Ca ephen This product from Planet Computers should floor—albeit looming down over us. Pros- our Tech Talk blog. t iller M never exist, according to conventional wis- thesis is a real-life mech or mecha, a type of

↗ Post your comments at https://spectrum.ieee.org/ han Et dom. It has two strikes against it: First, it is a giant piloted robot that dominates an en- cesgadgets0318 S Top: From

22 | Mar 2018 | SPECTRUM.IEEE.ORG RESOURCES_Careers

What Jobs Are Heating Up in Silicon Valley? Machine-learning skills are in demand

ot everyone can (or wants to) work in California’s Turning to the salary question, Indeed looked at job openings pos ted N Silicon Valley, but which Valley companies are hiring on its own website from November 2016 through October 2017. aggressively and what tech jobs are attracting the highest Product development engineer claimed the No. 1 spot, with an salaries there can have an influence throughout the global tech sector. average salary of US $173,570, and director of product management The job search firm Indeed recently released data covering both was just a few dollars behind, with an average salary of $173,556. questions, and there are a few surprises. For example, while marquee Meanwhile, salaries for DevOps managers, machine-learning Valley names like Apple, Cisco, Oracle, and Google dominated, the engineers, and cloud engineers are climbing fast, the data showed. No. 2 slot went to a company generally associated with Seattle: None of these three categories had previously made the top 20. Amazon. And the e-commerce group of mass-market retailer This year, DevOps manager ranked fourth, at $166,488; machine- Wal‑Mart Stores jumped in at No. 13, which reflects Wal-Mart’s re- learning engineer ranked 13th at $149,519, and cloud engineer cent push into artificial intelligence, according to Indeed’s analysis. ranked 16th at $146,900. —Tekla S. Perry companies hiring Salaries Rank Company Rank Job title Annual salary 1 Apple 1 Product development engineer $ 173,570 2 Amazon 2 Director of product management $ 173,556 3 Cisco 3 Data warehouse architect $ 169,836 4 Oracle 4 DevOps manager $ 166,488 5 Google 5 Senior architect $ 161,124 6 Facebook 6 Principal software engineer $ 160,326 7 Salesforce.com 7 Senior solutions architect $ 158,329 8 Intel 8 Principal Java developer $ 156,402 9 General Electric Co. 9 Senior software architect $ 154,944 10 Intuit 10 Platform engineer $ 154,739 11 VMware 11 Senior SQL developer $ 154,161 12 Visa 12 Senior C developer $ 152,903 13 Wal-Mart’s Global eCommerce 13 Machine-learning engineer $ 149,519 14 Workday 14 Software engineering manager $ 148,937 15 Adobe 15 Software architect $ 148,171 16 Nvidia 16 Cloud engineer $ 146,900 17 Yahoo 17 Senior product manager $ 146,277 18 Tesla 18 DevOps engineer $ 146,222 19 Paypal 19 Senior back-end developer $ 144,306 20 eBay 20 JavaScript developer $ 142,185

This article is adapted from two posts in our View From the Valley blog. ↗ Post your comments at https://spectrum.ieee.org/jobs0318

SPECTRUM.IEEE.ORG | Mar 2018 | 23 internet of everything_BY stacEY higginbotham opinion

At the same event, Johan Wibergh, CTO of Vodafone, said the real benefit of 5G is efficiency—the ability to deliver more bits at a lower cost. He claims that 5G will be 10 times more cost efficient than 4G LTE. That’s a good reason to upgrade, but not until carriers feel more pressure to improve profits. Meanwhile in the United States, Ve rizon and AT&T are rolling out 5G networks, but not for phones. Instead, they’re focused on the home broadband market, delivering what’s known as fixed wireless service over millimeter waves. Millimeter-wave spectrum is freely available for 5G for a reason—it has terrible signal propagation. Any obstacle in a signal’s path, including rain, trees, and people, can disrupt it. These links are cheaper to deploy than fiber, which explains whyVe rizon will launch its first fixed wireless service in Sacramento, Calif., later this year. Meanwhile, AT&T has been testing its own 5G broadband service in Austin, Texas; Kalamazoo, Mich.; and South Bend, Ind. Small and midsize cities could be the Curb Your 5G Enthusiasm perfect match for 5G broadband, according to Harold Feld, a senior vice president at the consumer advocacy group Public Just like graphene or Elon Musk’s startups, 5G has become a tech- Knowledge. Feld sees 5G as a potential nology savior. Proponents tout the poorly defined wireless technol- source of competition for consumers in ogy as the path to virtual reality, telemedicine, and self-driving cars. areas where major telecommunications But 5G is not a technology—it’s a buzzword unleashed by marketing firms have refused to lay fiber. departments. As early as 2012, Broadcom was using it to sell Wi-Fi. In reality, 5G But 5G can’t solve the problem of rural is a term that telecommunications investors and executives sling around as the connectivity. The technologies deployed solution to high infrastructure costs, the need for more bandwidth, and a desire for it will ultimately work best in sub- to boost margins. urbs and densely packed downtowns. The unifying component behind 5G is faster wireless broadband service. A more And rural operators worry about being stringent—and practical—definition is the use of high-frequency millimeter waves pushed out of their own markets. (in addition to the microwaves that 4G LTE relies on today) to deliver over-the-air First, 5G will do a credible job of broadband to phones or homes. providing faster broadband to homes If you’re talking about phones, 5G is still years away. And new services aren’t and offices in cities and towns. Then, really on the menu. Just listen to the heads of several telecommunications com- once its signal propagation challenges panies, who have begun to tamp down investors’ expectations around what 5G are sorted out, it will deliver mobile can deliver. data. It may even introduce new com- At an industry event last November, Gavin Patterson, CEO of BT Group, which petition to certain markets. But it isn’t operates British Telecommunications, said commercial service remains a long way magic, and rural customers deserve a off. The transition from 3G networks to 4G networks happened quickly, he said, better solution. n because there was immediate demand for faster data, driven largely by smart- ↗ Post your comments at https://spectrum.ieee.org/ phones. From his perspective, those 4G networks are still humming along just fine. 5g0318

24 | Mar 2018 | SPECTRUM.IEEE.ORG illustration by Dan Page Technology insight on demand on IEEE.tv Internet television gets a mobile makeover

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11-MEMB-0574b_IEEEtv_Spectrum_7x10_float_Final.indd 1 1/24/12 1:53 PM NUMBERS DON’T LIE_BY VACLAV SMIL OPINION

It was Hans Ziegler, an electronic engi- March 1958: neer with the U.S. Army, who overcame the U.S. Navy’s initial decision to use only batteries on the Vanguard. During VThe First P s in Orbit the 1960s, PV cells made it possible to power much larger satellites that revo- lutionized telecommunications, spying Sixty years ago this month, a rocket lifted off from Cape from space, weather forecasting, and Canaveral bearing the Vanguard 1 satellite, a small, 1.46-kilogram alu- the monitoring of ecosystems. As costs minum sphere that was the first to use photovoltaic cells in orbit. • As declined, applications multiplied, and a safeguard, one of the satellite’s two transmitters drew power from PV cells began to power lights in light- mercury batteries, but they failed after just three months. The six monocrystalline houses, offshore oil and gas drilling rigs, silicon cells, each roughly 5 centimeters on a side and delivering a total of just 1 and railway crossings. watt, kept on powering a beacon transmitter for 14 months, until May 1964. • It I bought my first solar scientific cal- happened in space because cost was no object. In the mid-1950s, PV cells ran about culator—the Texas Instruments TI-35 US $300 per watt. The cost fell to about $80/W in the mid-1970s, to $10/W by the Galaxy Solar—when it was introduced, late 1980s, to $1/W by 2011, and to about 40 cents per watt in 2017. That’s enough in 1985. Its four cells, each one about to bring the total system cost—for installations with single-axis tracking—close to 170 square millimeters, still serve me $1/W. Forecasts indicate that the cost will fall by as much as 60 percent further by well more than 30 years later. 2025. • This is good news because PV cells have a higher power density than any But serious electricity generation other form of renewable energy conversion. Even as an annual average they already had to wait for further module price reach 10 watts per square meter in sunny places, more than an order of magnitude declines. By 2000, global PV genera- higher than biofuels can manage. And, with rising conversion efficiencies and bet- tion had reached 1.2 terrawatt-hours; ter tracking, it should be possible to increase the annual capacity factors by 20 to a decade later it came to 33.8 TWh, 40 percent. • But the anniversary of the launch reminds us that it has taken quite and by 2016 it stood at 333.1 TWh. a while to get to this point. Edmond Becquerel first described the photovoltaic The annual rate of installation rose effect in 1839 in a solution, and William Adams and Richard Day discovered it in from the 0.015 square meters of the 1876 in selenium. Commercial opportunities opened up only when the silicon cell Vanguard 1, in 1958, to the approxi- was invented at Bell Telephone Laboratories, in 1954. Even then, the cost per watt mately 500 million m2 that were added remained around $300, and except for use in a few toys, PVs were just not practical. to solar farms and roofs in 2016—a rise of 10 orders of magnitude. But all that PV area still accounted for just 1.3 percent of the world’s total electricity. Another order-of-magnitude increase is thus needed before PV will rival global hydroelectricity generation, which sup- plied more than 16 percent of world demand in 2016. Not even the most optimistic forecast—that of the International Renewable Energy Agency—expects PV output to close that gap by 2030. But PV cells might be generating 10 percent of the world’s electricity by 2030. By that time some seven decades will have passed since Vanguard’s small cells began to power its beacon transmitter, and some 150 years since the photo voltaic effect was first discovered in a solid. Energy transitions on a global scale take time. n

↗ Post your comments at https://spectrum.ieee.org/ vanguard0318

Photo-illustration by Stuart Bradford reflections_BY robert lw.uc lkucy ky OPIOPINNIOIONN

Maybe they will be tinkering with carbon nanotubes, but whatever it is, the huffing and puffing will go on. The little engine will still be climbing the hill. Meanwhile, I see electronics design as riding a series of waves. For maximum professional opportunity, we just need to find where the big waves are, go there, and enjoy the ride. Right now the biggest waves are to be found in the world of cellphone electronics. As cellphone technology matures and plateaus, we have an enormous reserve in all the meticulously designed, high- volume components that make up our smartphones. Since smartphones do just about everything, there is a bonanza in that junk pile of parts. (Con- sider that the current renaissance in virtual and augmented reality was built on the back of light, cheap displays created for smartphones.) If it can’t be based on repurposed cellphone tech, the next approach is Riding the Wave to sidestep the fading improvements in general-purpose CPUs and adopt an application-specific architecture. of Electronics But this is a high-stakes game, and it’s necessary to find a big wave to ride. Being out by yourself, waiting for a tiny I’ve been hearing about the impending end of Moore’s Law wave, won’t do. At this point everyone for so many years that I’ve become skeptical of all the claims of doom. is racing to join all the surfers at the Like the Little Engine That Could, Moore’s Law keeps chugging along. machine-learning beach. Instead of Nonetheless, it has definitely reached the huffing and puffing stage. • CPUs, it’s all about TPUs—the tensor I was considering upgrading my desktop with a new CPU and motherboard, but processing units that do the batches new, comparably priced CPUs have about the same clock speed as my 4-year-old of flowing matrix multiplications that model. The newer ones do have more transistors and better architectures, so tech- implement deep learning in neural- nical benchmarks show about a 50 percent improvement. Nonetheless, when it network architectures. comes to everyday applications, the newer models might not exhibit noticeably On the other hand, if the volume better performance. I’m disappointed because I feel compelled to have the lat- isn’t there for a particular applica- est stuff at all times.• While transistors are continuing to shrink, it’s at a slower tion, you can hedge your bets with a pace. The technology road map calls for 5-nanometer fabrication by about 2020, field-programmable gate array. FPGAs but since we can’t run those transistors faster—mostly because of heat dissipation enable incremental design improve- problems—we will need to find effective ways of using more transistors in lieu of ments or adaptations to changes in increasing clock speed. And because of increasing fabrication costs, these designs requirements. Hardware is essentially will have to be produced at high volume. • No one knows what electronics will morphed into software—or the other be like in the future. It’s hard to think beyond Moore’s Law. Since the time of the way around. vacuum tube, there has been a century of exponential improvement. When I was So hurry and get in while the water’s a child, I thought that all future designs would simply be different arrangements warm. Maybe there’s a big wave coming. n of tubes, resistors, and capacitors. How little I knew! I’m sure that today’s budding ↗ Post your comments at https://spectrum.ieee.org/ engineers will feel the same way in the future. reflections0318

illustration by Harry Campbell SPECTRUM.IEEE.ORG | Mar 2018 | 27 28 | mar 2018 | SPECTRUM.IEEE.ORG

Television’s

Quantum dots will be the next darling of TV manufacturers By Zhongsheng Luo, Jesse Manders & Jeff Yurek The future of the television set was supposed At just a few nanometers in diameter, a quan- to be simple. At some point in the near future, tum dot is a tiny semiconductor, typically LCDs were supposed to become obsolete and zinc selenide, cadmium selenide, or indium give way to bright, sharp, and incredibly thin phosphide. It can do lots of useful things, but OLED displays. It turns out that the near future here we’re mainly interested in its ability to of TVs isn’t going to be so simple—but it sure is going to be bright. convert short-wavelength light—typically blue (450 to 495 nano- The reason? Quantum dots. If you’ve shopped for a TV lately, meters)—to nearly any color in the visible spectrum. you’ve probably been dazzled, or more likely perplexed, by When a quantum dot absorbs a photon, it generates an the array of new acronyms being splashed around by the electron-hole pair that recombines to emit a new photon. Cru- best-known TV makers. Perhaps you’ve wondered what they cially, the color of this emitted photon depends on the size of mean by QD, QUHD, SUHD, and ULED. We’re here to help. the quantum dot: Bigger dots emit longer wavelengths, close Each of these trade names refers to a quantum-dot technol- to red (620 to 750 nm); smaller dots emit shorter wavelengths, ogy available today. We’ll explain the different approaches closer to the violet end (380 to 450 nm) of the spectrum. Such as well as other ways quantum dots will be used in future “tunability” is unique to quantum dots. In other light-emitting television displays. Even if you’ve had your heart set on an materials, the wavelength of the emitted photon is a fixed OLED TV, we think you’ll find the coming world of very-high- property of the material and not affected by its dimensions. To performance quantum-dot displays appealing. For one thing, create a quantum dot with a specific size, which determines this emerging technology is going to finally make possible the wavelength, manufacturers adjust the temperatures and the printable, rollable, and wallpaper-ready televisions that the timing of the chemical reactions used in their production. we’ve all been promised for the past 20 years. That’s how the dots work. Now what does this have to do But to understand how televisions are going to make this, with the image on your TV screen? Every pixel you see on the er, quantum leap, first consider why people are using quan- screen emits red, green, or blue light, or some combination tum dots for TVs in the first place. of all three, for a total of more than a billion unique shades.

Many of today’s televisions use quantum dots to improve colors produced by liquid crystal displays (LCDs), backlit by light-emitting diodes (LEDs). Meanwhile, The Structure researchers are developing ways to use these dots to create even better quality television images. TVs made with organic LEDs, a competing technology long thought of a TV Display to be the next revolution in television, remain expensive.

Photo-Enhanced Quantum-Dot TV In this variation of LCD technology, quantum dots inserted between an LED array and color filters purify the television’s backlight to improve color reproduction. Advantages: Deep color at high peak luminance • Low cost • No burn-in • Manufactured using existing color filter glass panel qd Enhancement film backlight LCD infrastructure • Available now

OLED TV This ultrathin display technology doesn’t involve quantum dots and was long thought to represent the future of television. Advantages: Deep black levels • Excellent viewing angle • Fast refresh • Can potentially be manufactured on flexible color filter anode emitters cathode substrates • Available now

30 | mar 2018 | SPECTRUM.IEEE.ORG illustration by James Provost How accurately these shades match the colors recorded by red, green, and blue light. So another option for enhancing the cameras on the street or in the studio depends on how image quality is to create a backlight whose white light is a exactly a TV reproduces the specified wavelengths—that is, combination of these three colors, each of which has a spec- how narrow the spectrum is for each color. tral distribution with a sharp and narrow peak. Today’s LCD televisions, the type you probably have in your The best option by far is the latter. Narrowing the filter home, produce colors using a light source—the backlight—that dims the image, never a good thing for television displays. So appears bluish white. Nowadays, that backlight is usually based display engineers have focused on improving the backlight. on an array of white-light LEDs. (Older LCD models used fluorescent lamps rather than LEDs.) At each pixel, there are red, That backlight in a budget TV today works in green, and blue subpixels. Each of these is just a tiny patch much the same way as the white-light LED with a colored filter and a liquid crystal shutter that controls bulbs that are increasingly ubiquitous in our how much light streams through that filter. By varying the rel- homes. These white LEDs efficiently produce ative proportions of the light emitted by each of the subpixels, enough of the visible spectrum to let us read- the pixel can create most of the colors that are reflected by ily perceive it as white. the natural world. And the key point here is this: The purer In a typical white LED backlight, a gallium nitride LED gen- the light at each subpixel, the narrower the spectrum and the erates blue light. That light then excites an yttrium aluminum more precisely colors can be mixed at that pixel. garnet phosphor, which generates yellow light. The yellow LCD television manufacturers have two ways of making sure and blue together create a light that appears white but is rich the spectrum of light coming from each subpixel is narrow. in yellow and blue wavelengths and weak in green and red. One method uses, at each subpixel, very strict filters, which When the LCD subpixels on top of the backlight filter this allow only a narrow spectrum through in each of the primary light into red, green, and blue components, there is simply colors of red, green, and blue. The alternative is to tinker with not enough energy at the required wavelengths of red and your backlight. Recall that white light can simply be a mix of green to produce a bright image using just that light. The filters

Photo-Emissive QD TV The quantum dots replace the filters and become the red and green subpixels themselves; the blue backlight excites the dots and creates the blue subpixels. Advantages: Wide viewing angle • Potential threefold jump in efficiency and brightness over LCDs • Manufacturers QD array panel backlight can use existing LCD infrastructure

Electro-Emissive QD TV These quantum dots emit light themselves when an electric current is applied, so no backlight is involved. Advantages: Perfect viewing angle • Perfect black levels • Potential low-cost manufacturing • Fast refresh rate • Flexible substrates • No filters needed • anode Electroluminescent QD stack cathode Long lifetimes

Micro-LED TV With QDs This variation of micro-LED technology involves an array of microscopic monochrome LEDs, with quantum dots providing color conversion for the red and green subpixels. Advantages: Perfect viewing angle • No filters needed • Perfect blacks • Brightest technology • Fast QD array LED array refresh rate • Flexible substrates possible

SPECTRUM.IEEE.ORG | mar 2018 | 31 compensate for this lack of energy by letting through broader • They waste energy. At each subpixel, an LCD TV has to block ranges of colors. So the green subpixel contains a mix of blue about two-thirds of the light generated to separate red from green through yellow green, while the red includes orange blue and blue from green. all the way through infrared. With such imperfect colors, it • They struggle with showing deep, dark, true blacks in low- is impossible for the subpixels to mix light from those three light viewing environments. Because the liquid crystals aren’t primary components into the precise colors we see when we perfect light blockers, a small quantity of white light leaks look around us at the world as lit by the sun. through to the viewer. This can make black images appear That’s where quantum dots come in. Inserting quantum closer to a dark gray (technically speaking, these images have dots between the LEDs and the filters can improve the pic- “limited dynamic range”). ture by maximizing the amount of light coming through at • They have relatively slow switching speeds. These speeds precise red, green, and blue wavelengths, and by minimizing stem from the very nature of liquid crystals. These crystals are the energy used to produce light between those wavelengths actually twisted by an electric field, which polarizes the light [see diagram, “Photo-Enhanced Quantum-Dot TV,” in “The coming through them. The polarization is used to block light Structure of a TV Display”]. A typical approach involves using or let it through at each subpixel. But this twisting takes time, an LED that emits blue light at 450 nm, paired with quantum and the lag can cause trouble for fast-motion content like sports, dots coated onto a film that slides into the back of the display action movies, or gaming. The upshot is that LCDs can support panel. The dots on that film are a mix of two versions: 1.5- to a refresh rate of about 240 hertz, at best. Some state-of-the-art 2.5-nm-diameter dots emitting 527-nm green light, and 3.0- TV systems are already experimenting with such high refresh to 5.0-nm dots emitting 638-nm red light. rates, though the traditional TV refresh rate is 60 Hz. So in this setup, instead of using the blue LED to excite a phos- • They are not foldable or rollable, at least with available tech- phor that produces yellow light, the manufacturers use it to excite nology. That limits the form factor of today’s displays. red and green quantum dots with sharp, narrow spectra, and also to directly produce the necessary blue light. This scheme These limitations have led many observers more precisely matches the specifications for television color to conclude that LCDs will be replaced in the reproduction than the blue-yellow approach, and as a bonus, foreseeable future by an emissive display tech- less light is lost when it passes through red and green filters. nology, namely organic LEDs (OLEDs). An This approach creates a “photo-enhanced” quantum-dot emissive technology is one in which the sub- display. It gives quantum dots a supporting role in the TV dis- pixels themselves emit red, green, and blue light, rather than play world—but it’s only an interim step. The problem is that, creating it with colored filters in front of a white backlight. even with the help of quantum-dot films, LCD TV displays Emissive technologies have natural advantages, like deep black still have some inherent flaws: levels, wide viewing angles, and, with some types of emissive • Their viewing angle can be narrow. Newer liquid crystal technologies, faster switching times. The picture quality can technologies exist that overcome much of this problem, but be quite spectacular, but OLEDs have some lingering chal- they are expensive. lenges, mainly in cost, power consumption, and longevity.

LIGHT IN A BOTTLE: In future TVs, electrons could directly stimulate quantum dots, like those emitting blue light in the device shown [left]. Vials of green and red cadmium-free quantum dots glow in response to that light and an off-camera blue-light source. osys n Na

32 | mar 2018 | SPECTRUM.IEEE.ORG OLED technology involves inserting a thin film of an organic a color filter array, instead replace it and become the subpix- substance between two conductors; applying a current causes els themselves. In this approach, blue LEDs again make up the film to emit light [see “OLED TV”]. Various small gadgets a backlight. The blue subpixels are simply transparent spots and smartphones by Samsung, Google, and now Apple use a in the array; light passes through them mostly unchanged. kind of emissive display called RGB (red, green, blue) OLED. The green and red subpixels, each made up of quantum dots, Unfortunately, it turns out that RGB OLEDs cannot be reli- absorb energy from the blue light and then emit precise wave- ably manufactured in the large sizes needed for TVs. So TV lengths of green and red light, respectively. The light doesn’t manufacturers switched to a variant—white OLED, or WOLED. require any filtering. Today, LG Display is producing WOLED displays in TV screen The best-performing dots today emit light with over 99 per- sizes for its own use and for use by other TV vendors; Sony, cent efficiency. When combined with the efficiency gains that Panasonic, and Samsung have gotten out of the business of come with removing the filter, these dots can create a picture manufacturing their own OLED TV displays. as much as twice as bright as today’s LCDs with twice the effi- WOLED displays use a mix of blue and orange-yellow OLED ciency. This display also has a wide viewing angle because emitters to create a white light. That light then passes through the quantum dots sit at the front of the screen and emit light a layer of red, green, and blue filters to create the colored in all directions. subpixels; a fourth, open subpixel lets unfiltered white light Photo-emissive QD televisions aren’t on the market yet. through to brighten up the entire image when necessary. Expect to see mass production start later this year, with wide- These displays have a few formidable advantages—they can spread availability in 2019. produce deep black levels, have blazingly fast switching speeds There are a few reasons why this technology has taken sev- (10 times that of LCDs), and are thin and flexible. Future appli- eral years to become ready for commercialization. The main cations of OLED panels could take almost any form factor; issue was stability. Initially, quantum dots weren’t very stable they can stretch, bend, fold, roll, stick like wallpaper, or be in air, so in early photo-enhanced quantum-dot displays they transparent. were sealed inside glass tubes. In today’s photo-enhanced dis- However, against these strengths must be weighed some plays, a protective plastic coating is used over the quantum sobering weaknesses. WOLED isn’t a very energy-efficient dots, but the sheet is left unsealed at the edges. technology. To date, only about 10 percent of the electric Early quantum-dot displays had another challenge to over- current that runs a blue OLED gets converted into photons come—they contained the element cadmium, an environmen- that come out of the display. The figure for the orange-yellow tal hazard. Bringing quantum dots made of noncadmium emitters is a little over 20 percent, which is near the theoreti- materials up to the color quality of cadmium materials hasn’t cal maximum efficiency. And, even more important, adding been easy. The noncadmium and low-cadmium materials we color filters further reduces efficiency. The total light loss at use today still don’t have quite the same purity of color, but the filter can be as much as 75 percent. Consumers might not they are good enough for most display applications. notice the high power consumption of their TVs—but the light For photo-emissive displays, the challenges mounted. It loss also makes for a less-impressive image. took a while to find a way to reliably pattern the dots into WOLED displays also come up a little short in color repro- subpixels at high resolution. Our company, Nanosys, chose duction; the broad-spectrum light they produce reduces the to focus on photolithography first because that is how LCD purity of the red, green, and blue subpixels, and the white sub- color filters are made today, and this approach would there- pixel that boosts bright images tends to wash out their colors. fore be minimally disruptive to display manufacturers. That WOLED-based TVs, particularly their blue emitters, cur- meant, however, that the quantum dots had to be processed rently face longevity issues. This problem shows up in an in air, not a vacuum, and also had to be rugged enough to image artifact called burn-in, which can occur after only nine remain stable under the various thermal and chemical steps months of use in a typical U.S. home. of LCD fabrication. Finally, OLED displays are still very expensive to produce. A Finally, they had to operate long enough to meet the expec- typical OLED device is made up of 25 superthin layers, requir- tations of TV purchasers, which is about 10 years of normal ing multiple manufacturing steps that must take place under use. As of this writing, we have met these challenges. a high vacuum. That’s why a typical 65-inch OLED TV with This architecture created a few challenges for the display 4K resolution today sells for about US $3,000, as compared makers as well. One critical issue was preventing ambient with about $1,000 for an LCD set of similar quality. room light from exciting the dots. Panel makers have come up with proprietary solutions to both these problems. That brings us back to quantum dots because, Photo-emissive quantum-dot technology will make flex- as it turns out, we can use them for some- ible TVs possible. So far, TV manufacturers have focused on thing other than to purify backlights: as an adapting traditional LCD manufacturing techniques to quan- emissive display technology. tum dots. But researchers are excited about the possibility of The first form of emissive quantum-dot dis- printing QDs onto plastic or other flexible materials. Because plays will be photo-emissive [see “Photo-Emissive QD TV”]. QDs are so small and are initially produced in a solution, they In this scheme, the quantum dots, instead of hiding behind very much resemble printing inks. So | continued on page 52

SPECTRUM.IEEE.ORG | mar 2018 | 33 Building a Safer, Denser

Lithium- Chipmaking techniques contribute to ion a design that outperforms today’s Battery best cells

By Ashok Lahiri, Nirav Shah & Cameron Dales

34 | MAR 2018 | SPECTRUM.IEEE.ORG Illustration by Jean-Luc Fortier SPECTRUM.IEEE.ORG | MAR 2018 | 35 Hardly a month passes without up the manufacturing volume and that with mass production the unit cost will decline at rates similar to those achieved in shocking news of lithium-ion the solar-cell industry.

batteries catching fire: Laptops wohallenges key c faced Sony Corp. when it are torched, airlines are grounded, decided to commercialize the Li-ion battery back T in 1991. Its handheld camcorder—a harbinger of hoverboards go up in flames. many power-hungry portable devices to come—needed a very high capacity battery in a compact package. And audio The 2016 fires inside Samsung’s cassettes were quickly giving way to compact discs. The latter is relevant because magnetic recording tape for Galaxy Note 7 smartphone led to audiocassettes was made on manufacturing lines that coated a US $5 billion recall and then to a a plastic film with a magnetic slurry, dried it, cut it into long strips, and rolled them up. Because the compact disc used discontinuation of the model, moves a very different production process, Sony suddenly found itself with a surplus of equipment for manufacturing mag- that together cut Samsung’s market netic recording tape and of technicians to run these machines. Managers in Sony’s battery division realized they could solve capitalization by many billions. the problem at a stroke by employing the same manufacturing equipment and personnel to coat chemical slurries onto In January 2017, after months of speculation, Samsung metal foil, dry it, and cut it into electrode sheets. Then, to announced that two separate design problems created the form the core of the battery, two sheets were interlayered battery malfunctions that caused some of the devices to over- with a polymer separator, which allows ions, but not elec- heat. That different design flaws can produce the same cata- trons, to flow between the electrodes, and the whole stack strophic outcome underlines the inherently unstable nature was wound together like a jelly roll. This same production of today’s Li-ion batteries. Any mobile product incorporating model—built around coated metal-foil current collectors— them is thus potentially unsafe. has been used by Li-ion battery manufacturers ever since. That danger is a result of design and production deci- This design was clever, but it made it harder to improve these sions made a quarter century ago, when this type of bat- batteries over the long term. For one thing, it wastes space. tery was initially commercialized. Those decisions made Within the assembled battery, the only materials that store sense at the time, but today we can do much better, above energy are the particles that make up the anode (negative all by taking advantage of fabrication techniques honed electrode) and cathode (positive electrode). The metal-foil by the chipmaking industry. Our company, Enovix Corp., current collectors, separators, and packaging materials, as in Fremont, Calif., has done just that, and we have dem- well as empty space, typically make up at least 40 percent of onstrated that we can produce Li-ion batteries that are total volume. Having so much space devoted to something smaller, less expensive, and fundamentally safer than other than storing energy lowers the battery’s energy density, anything now on the market. a quantity typically measured in watt-hours per liter (Wh/L). Early this year, we began pilot production of our battery at For example, conventional Li-ion cell construction for mobile our subsidiary, Enovix Philippines. We believe we can scale devices usually involves winding the electrode sheets and separator together and then flattening the resulting spiral to fit into a slim metal case or plastic 1. Heating starts. Anode (Carbon) pouch. This process requires a certain length 2. Protective layer of blank—that is, uncoated—current collec- breaks down. Protective layer tor and separator at the beginning and end, 3. Electrolyte which takes up volume but doesn’t store energy. breaks down into Electrolyte flammable gases. (Lithium salt in Empty space may also be left in the center of the organic solvent) cell and along the two sides of the cell, where it 4. Separator melts, is rounded due to the wound-up construction. possibly causing a short circuit. Separator The polymer separator is an inactive material and must be physically longer and wider than 5. Cathode breaks Cathode down, generating (Lithium metal the electrodes to ensure that the electrode edges oxygen. oxide) do not touch each other. One way to increase the energy density is by slimming down the Thermal Runaway: The construction of a conventional Li-ion cell, adapted from techniques used to produce magnetic audio-recording tape, makes it susceptible to separator. If it gets too thin, however, the bat- thermal runaway, which can result in catastrophic damage from explosions or fires. tery becomes prone to shorting out.

36 | MAR 2018 | SPECTRUM.IEEE.ORG illustration by Erik Vrielink Separator Cathode current collector Anode Anode current collector Separator

Backbone Backplane Anode Cathode Cathode

Rolled Up: This internal cross-section view of a conventional Li-ion Densely Packed: The 3D cell architecture orients and interlaces a cathode, battery shows anode and cathode sheets that have been wound with polymer a 100 percent silicon anode, and a ceramic separator in a thin (1-millimeter) separator sheets, flattened, and packaged in a metal case. flat plane, which significantly improves energy density and safety.

Another problem is the presence of microscopic metal icroelectromechanical systems (MEMS), particles—introduced unavoidably during assembly—which fabricated in three dimensions with photolithogra- can accumulate on an electrically active spot, creating a M phy, provided the model for the research that one major short circuit that shunts enough current between the of us (Lahiri) and two other cofounders of our company began electrodes to sharply raise the temperature. That heat, in in 2007. We already had experience in developing such MEMS turn, may affect neighboring areas, setting off what’s known designs—initially for use in high-density disk-drive read-write as thermal runaway, which can produce an explosion and heads, and then for testing semiconductor wafers. fire. It’s practically impossible to eliminate metal particles, That collaboration resulted in the founding of Enovix Corp. because they are generated by the cutting, rolling, and wind- (originally called microAzure Corp.) and the initial funding of ing machinery during the production and assembly processes. the company by several Silicon Valley venture capital firms. Additional problems can occur during charging, when The company’s first goal was to conduct proof-of-concept lithium ions flow from the lithium metal oxide cathode to research on a lithium-ion rechargeable battery that used sili- the graphite anode (the standard anode material in virtually con in place of the usual graphite for the anode. By 2012, the every Li-ion battery used in mobile devices). Normally, the company was producing cells that had a much higher energy lithium ions fit into the gaps in the crystal lattice structure density than conventional Li-ion cells of comparable size. of the graphite—a process known as intercalation. But a high Enovix then began to develop a low-cost high-volume pro- charge current, a local lack of active anode material, or a low duction system, with the help of strategic investors Cypress ambient temperature can cause lithium ions to instead plate Semiconductor, Intel Capital, and Qualcomm Ventures. on the surface of the anode. Lithium metal may then accu- Cypress Semiconductor had previously helped its mulate as threadlike structures known as dendrites, which SunPower subsidiary produce high-performance solar cells grow as the cell is charged and discharged, eventually punc- at a much lower cost and at a higher volume than could be turing the separator and creating a short, which can lead to done by other companies with their complex, multistep pro- thermal runaway. Finally, conventional Li-ion batteries can cesses. Since 2014, Enovix has been developing and refining become unstable if they get too warm, which also can lead methods to construct its battery, based on SunPower’s pro- to thermal runaway. duction techniques. These problems were offset by the great edge in energy den- The Enovix battery uses a three-dimensional cell architec- sity Li-ion has over nickel cadmium—the previous standard for ture in which the electrodes are etched into a silicon wafer rechargeable batteries in consumer electronics. But since the and plated metal current collectors, which are much thin- Li-ion battery was introduced, its energy density has improved ner than the foil used in conventional cells. By interlacing a at only about 5 percent a year. That’s because of production cathode, an anode, and a separator on the 1-millimeter-thick constraints and the slow pace of development of new materi- wafer, it significantly reduces wasted space. In our battery, als for the electrodes and electrolyte. Meanwhile, the power a full 75 percent of the volume is dedicated to storing energy. demands of mobile devices—particularly smartphones, tab- This alone increases capacity by about 25 percent over conven- lets, and wearables—are increasing at many times that rate. tional cells. Similarly, the weight goes down proportionally Fortunately, another set of techniques, ones borrowed from for a battery of a given capacity, although typically volume the semiconductor industry, can do much better. is the more critical constraint in mobile devices.

Illustration by Jean-Luc Fortier SPECTRUM.IEEE.ORG | MAR 2018 | 37 1 2

SILICON CELL [1]: Close-up view of a single, 1-millimeter 3D silicon cell after photolithographic processing but before current collector plating, ceramic separator deposition, and cathode slurry injection. WAFER INSPECTION [2]: A technician at the Enovix facility in Fremont, Calif., examines a 3D silicon wafer after photolithography and etching. PILOT PRODUCTION [3]: This standard solar-cell fabrication equipment is used in the pilot production of 3D cell wafers in Fremont; similar equipment is being installed for the manufacturing scale-up phase at the company’s Philippines plant. PROTOTYPE BATTERY [4]: This prototype 3D silicon lithium-ion rechargeable battery is packaged in a size suitable for a smart watch. The cutaway shows how it is constructed from three 1-mm cells stacked one upon another.

Our flat-cell architecture can take full advantage of a This explains why commercial Li-ion batteries have so far been number of advances in electrode chemistry. To understand limited to about a 5 to 10 percent silicon-to-graphite blend. why that’s so, you need to know a little more about how Enovix gets around this problem by making its silicon porous a conventional Li-ion battery works, in particular about so that expansion pushes its tiny internal cavities together how the graphite anode absorbs lithium ions when the rather than swelling the entire anode. This feature maintains battery is charging and emits them back into the electro the structural integrity of the connection between the anode lyte when the battery is discharging. At the anode, one and its current collector during repeated charge-discharge atom of lithium combines with six atoms of carbon in cycles. This ability to control anode expansion is one of the the graphite to form LiC6. This gives graphite a theoreti- key advantages of our system over the conventional Li-ion cal specific capacity of about 372 milliampere-hours per battery architecture that Sony pioneered. gram. Because the ratio of lithium to carbon atoms is 1:6, Depending on size and thickness, our cells pack into a given only modest swelling occurs. volume from 1.5 to 3 times as much energy as conventional Instead of graphite, we use silicon for the anode material. Li‑ion cells do. Because our battery architecture makes it

Silicon is attractive because it forms a Li22Si5 alloy. That very possible to exploit a wider variety of electrode materials, we high ratio of lithium-to-silicon bonding allows silicon to store expect to take advantage of ongoing research in materials, about 4,200 mAh/g, an extraordinary amount. But silicon’s which so far has improved the performance of conventional increased absorption of lithium ions can cause it to swell by batteries by roughly 5 percent per year. But because we can up to 400 percent. also exploit future efficiency gains within our structural design, Of course, any design that exploits the increased capacity we expect the energy density of our batteries to improve two of a silicon anode would have to match it on the other end to three times as fast as that of conventional batteries. by adding to the thickness of the cathode or using a better The other great advantage of our design is improved safety. material. Commonly used cathodes such as lithium cobalt How do we achieve that? For one thing, we use a better separator. oxide (LCO), lithium nickel manganese cobalt oxide (NMC), In a conventional Li-ion cell, the separator is typically made of and lithium nickel cobalt aluminum oxide (NCA) have usable a plastic or polymer material because it must be flexible enough capacities of 140 mAh/g, 170 mAh/g, and 185 mAh/g, respec- to roll up. As a result, conventional separators are more likely tively. Right now, we are using an NCA cathode, sized to to fail under high temperatures. Our flat design can accom- match the capacity of the silicon anode. However, we can modate a ceramic separator, which is far more tolerant of heat. use any of the conventional Li-ion cathode materials, and Also, our silicon anode’s ample capacity to absorb lithium that flexibility should allow us to meet the requirements of without swelling makes it much less susceptible to lithium specific applications. plating, even with a high charge current. Should an electrical Although it’s possible to add silicon to the anodes of conven- short occur anyway, our use of many distributed electrodes— tionally produced batteries, you can’t add too much. That’s as opposed to long sheets—will limit the current that can flow because as silicon absorbs lithium and expands, it eventually between any individual anode/cathode pair, which greatly

pulls the anode apart from the metal-foil current collector. reduces the risk of thermal runaway. (4) Enovix

38 | MAR 2018 | SPECTRUM.IEEE.ORG trically connected on the wafer, we can selectively electroplate different coatings on each. To create the cathodes, we inject a conventional cathode slurry, filling the remaining voids in the wafer. Then a laser slices off one 1-mm-thick die after another from the wafer, with the lateral dimensions of each die approximating the dimensions of the final battery. Positive and negative tabs are then attached to each die, which are baked to remove moisture, and stacked to form the desired height of the battery. The tabs are all connected to form a single positive and negative tab for the cell, and the resulting stacked cell is then pouched or inserted into a metal can, which is filled with electrolyte, sealed, and tested. 3 4 The architecture, silicon wafer photolithography, and etching process we employ are comparable to what is used in three-dimensional MEMS. Hence, we dubbed our device the 3D Silicon Lithium-ion battery. We compared Our cathode design is safer, too. Typically, when cathode a prototype with a conventional Li-ion battery having the same material hits a critical temperature (as can happen near a form factor, one designed to fit in a smart watch (that battery short), it spontaneously breaks down, releasing oxygen that was 18 by 27 by 4 mm). Our internal tests showed our battery can fuel a fire. This breakdown can proceed from cathode to have much higher capacity and a corresponding increase particle to cathode particle as the next particle hits the criti- in energy density—695 Wh/L as opposed to about 460 for the cal temperature, fueling a thermal runaway. Our architecture conventional cell. breaks the cathode up into hundreds or thousands of tiny Much of this manufacturing technology comes, of course, segments separated by silicon, which conducts heat nearly from the solar-cell business. The progress in that field—fueled as well as aluminum, making it hard for a runaway reaction by immense R&D investment worldwide—at once explains to get started. By contrast, a conventional wound battery’s the low cost of our manufacturing approach and the like cathode is one long sheet, allowing runaway reactions to lihood that it will continue to improve in efficiency and scale. quickly spread through the device. All these features, taken together, essentially eliminate the onsumers yearn for better and more pow- danger of explosion and fire. erful batteries for their mobile devices, as survey We recently compared our prototype cell for a wearable C after survey attests. Most demanding of all are the device with a comparable commercial Li-ion cell by deliber- wearable devices and microsensors that are being created for ately creating a precarious scenario. We overcharged a con- the Internet of Things. Such IoT devices have even less room ventional 130-mAh Li-ion cell and our 100-mAh silicon Li-ion in them for batteries than do tablets and smartphones. cell to 250 percent of capacity and simultaneously punctured This wouldn’t be the first time that photolithography and the package of each (through the standard nail-penetration wafer production have suddenly revamped whole industries. test). The conventional Li-ion cell burst into flames, but our It happened first when computers began to use integrated silicon Li-ion cell did not. circuits. These fabrication techniques were also applied to lighting, which moved from fluorescent tubes to light-emitting o fabricate the Enovix battery, we begin with diodes and to video displays, which went from cathode-ray a wafer of silicon that’s 1 millimeter thick. This doesn’t tubes to liquid crystal displays. T have to be the chip-grade stuff—it can be the same We believe that the approach we’re pioneering will bring low-cost material that is used to produce solar cells. To the about a similar transformation in the market for lithium-ion wafer we apply a photolithographic mask and etch the required batteries. The change will first appear in wearables, next in pattern with typical silicon etchants borrowed from the solar IoT and phones, and ultimately in electric vehicles and grid industry. Because the pattern can vary in shape—square, rect- storage, as volumes scale up and manufacturing costs come angular, round, oval, hexagonal—as well as in length and width, down. This change has already occurred in the solar industry. we have the ability to form a wide variety of cell designs. The With safer, thinner, and higher-energy batteries, designers silicon that’s left behind where the mask was placed forms the will have more flexibility to create breakthrough products. anodes and “backbones” of the interlaced cell structure. Expect mobile devices to get smaller, to last longer between Next, we selectively deposit a thin coat of metal film onto charges, and to continue to deliver amazing new capabilities the anodes and backbones to form current collectors and to enhance our lives. n then deposit a ceramic separator around the collector on Join the conversation about this article, which originally appeared online, at https://spectrum. the anodes. Because the anodes and backbones are not elec- ieee.org/lithiumion0318

SPECTRUM.IEEE.ORG | MAR 2018 | 39 G R .IEEE.O M U R SPECT

| mar 2018 mar

ts Driving Tes for Self- Driving Cars Nilsson

y Erik Coelingh B & Jonas jude buffum

tion by tra

illus ts Driving Tes for Self- Driving Cars A ut be saferonomous c driven ones. But it will be than human- ars should

tricky proving

tational platforms already intervene to they want to know how the vehicle will avoid accidents, turning cars into guard- respond. For us, the biggest question is ian angels for their drivers. Vehicles will “How do we know the vehicle is safe?” continue taking over more driving tasks But before that, we must first ask what until they’re capable of driving them- it means for a self-driving vehicle to be selves. This will be the biggest trans- safe. Safe doesn’t mean perfect; perfect portation revolution since cars replaced information about the environment will horse-drawn carriages. never be available. Instead, it must mean But it’s one thing to build a self-driving the self-driving vehicle can handle the vehicle that works, and quite another problems it’s designed to handle, like to prove that it’s safe. Traffic can be as obeying speed limits, yielding to a car unpredictable as the weather, and being merging into its lane, or observing right- able to respond to both means navigat- of-way at a stop sign. And it must also rec- ing countless scenarios. To fully test ognize when it is at risk of exceeding its At a test track east of Gothenburg, all those scenarios by simply driving design specifications. For example, the Sweden, people are ushered into around would take not years but cen- vehicle shouldn’t attempt to drive after autonomous vehicles for a test drive. turies. Therefore, we have to find other being placed in the middle of the forest. But there’s a twist: The vehicles aren’t ways to assure safety—things like com- In 9 out of 10 accidents resulting in Aactually autonomous—there’s a hidden puter simulations and mathematical fatalities or major injuries, mistakes driver in the back—and the people are modeling. We’re combining real traffic by the driver are a contributing fac- participating in an experiment to dis- tests with extensive augmented-reality tor, according to multiple U.S. and U.K. cover how they’ll behave when the car simulations and test cases on one of sources. Because of this, the quick is chauffeuring them around. the world’s most advanced test tracks answer to what is “safe enough” is usu- At Zenuity—a joint venture between to truly understand how to make self- ally “better than a human driver.” But Volvo and Autoliv, a Swedish auto-safety driving cars safe. the devil is in the details. It’s too easy a company—this test is just one of many challenge to surpass the drunken driver ways we make sure not just that autono It’s easy for a self-driving vehicle or even the statistically average driver. mous vehicles work but that they can to cruise down a straightaway in the mid- The median driver, you might argue, is drive more safely than humans ever dle of a sunny day. But what about what not very good. could. If self-driving cars are ever going we call corner cases—scenarios in which We propose that self-driving cars be to hit the road, they’ll need to know the several unlikely factors occur together? held neither to a standard so strict that rules and how to follow them safely, A road littered with fallen branches dur- it delays the introduction of a life-saving regardless of how much they might ing a thunderstorm poses different chal- technology nor to one so lenient that it depend on the human behind the wheel. lenges to a vehicle than an elk crossing treats the initial customers as guinea Even now your car doesn’t need you as the road while the sun is setting. pigs. Instead, the first self-driving vehi- much as it once did. Advanced computer Manufacturers will likely be held liable cles should be demonstrably safer than vision, radar technology, and compu- for vehicles that react incorrectly, and so a vehicle driven by the median human

SNOW-DAY SAFETY: In bad weather situations like heavy snowfall, a self-driving car must recognize that its radar [left], cameras [right],

and other sensors could be impaired, and adjust its driving strategies accordingly. (2) Zenuity

42 | mar 2018 | SPECTRUM.IEEE.ORG driver. We believe that if every compo- is tested in real traffic until we can say, nent can be demonstrated to work better with statistical significance, that it’s safe— than a human and if the complex algo- and that would take hundreds of mil- rithms that govern each component can lions or even billions of hours on the interact together to drive the vehicle, it’s road. The first automobiles were tested reasonable to conclude that the car is a in this fashion, even if the people who better driver than the human. drove those cars were unwitting partici- This means designing the vehicle’s pants in the experiment. A Crash Course systems to handle any situation within It’s also possible to use a divide-and- in Self-Driving its scope and discount the rest. While conquer approach. Rather than ask a it is possible a parachutist could land complex question, such as whether the Vehicle Safety directly in front of the vehicle, it is so vehicle’s sensors can spot a deer crossing Tests extremely unlikely it is not required to the road during a blizzard, it’s easier to consider that scenario for safety tests. ask simpler questions, such as whether Any potential for unsafe behavior— the car can tell when its sensors are “Wizard of Oz” cars software bugs, hardware failures, sen- blocked by snow, or when hardware Test “drivers” are placed sor limitations, unexpected weather has failed due to cold temperatures. To in a vehicle they believe is autonomous to see how they conditions—must be shown to be very that you could add the question, “If yes, react to being in a self-driving car. rare. Our rule of thumb is that any one can the vehicle adjust its decision mak- In reality, a driver hidden in the of these problems should occur less than ing accordingly?” We can then tackle backseat is steering the vehicle. once in a billion hours of operation. At each of these smaller questions with that low failure rate, all of these poten- whichever verification method is best Computer tial causes considered together still pro- suited to answer it, whether that’s a com- simulations duce a vehicle that is not only safe but puter simulation, a quick spin on a test There are some situations you just can be made available without taking track, or putting the car in a real traf- can’t test in real life, like a deer jumping in front of the vehicle. For too long to test. fic situation these situations, the best option However, we shouldn’t expect the car In reality, any practical approach will is to run computer simulations to to solve a problem that even the very fall somewhere between brute-force see how the vehicle behaves. best human driver could not solve. One testing and the divide-and-conquer such problem, often trotted out by ethics mode. Because technology develops Test tracks professors and the media, is the trolley in fast iterations, it would be wise to Zenuity is testing vehicles on dilemma. In this hypothetical scenario, emphasize divide and conquer. For Sweden’s AstaZero test track. The massive track provides someone must choose between doing example, whenever the hardware or multiple settings, including nothing and allowing a runaway trol- software is changed, any data collected simulated residential areas, ley to kill several people on one track, by a brute‑force approach may no longer highways, and forested areas. or actively throwing a switch, allowing be valid. Divide and conquer directs us the trolley to kill one person on another to focus on retesting the safety of only Real traffic tests track. The parallels to self-driving vehi- the systems that were updated, while When a test track just isn’t real cles are clear. What if a vehicle winds avoiding a time-consuming regather- enough, vehicles can be tested in real traffic situations, whether up in a situation where it must choose ing of data we already have. that means manually driving between killing several pedestrians or To tackle divide-and-conquer situations, the car to gather sensor data or swerving into a barricade and killing we divide a self-driving vehicle’s sys- seeing how the car handles on its own, with supervision. its own driver? tem into four components—the human- But this question is a red herring. machine interface, perception, decision Given that the risk of ending up in any making, and vehicle control. The human- Testing cameras fatal accident is low, then the risk of end- machine interface has to do with the way To understand what the car “sees,” the cameras can be tested ing up in a situation where a choice must the vehicle and its user interact. Percep- by showing them prerecorded be made between two is even lower. All tion is how the vehicle’s sensors create a footage, or by logging what they we can demand of self-driving cars is view of its surroundings, decision mak- pick up during a manual drive. that they should avoid such impossible ing plans how the vehicle should respond choices to begin with. to that view, and vehicle control is the Impairment plan’s physical execution. Each compo- awareness Once we have what appears to be a nent has its own corner cases and meth- Placing the car’s radar or cameras safe automated vehicle, we are obliged ods to verify that it will be acceptably safe. in snowy or wet test conditions tests whether the car’s “brain” to prove it safe. One way is through a Consider the user interface in a car can detect when the sensors brute‑force method. Here, the vehicle that drives itself most of the time but themselves are obstructed.

illustration by Jude Buffum SELF-DRIVING SIMULATIONS: It’s too dangerous to test some scenarios, like a pedestrian stepping out in front of a self-driving car in motion, so those kinds of tricky “corner cases” are conducted in simulations to find out how the car responds. still requires occasional human inter- easy to point the camera at a screen dis- ner cases, such as detecting debris on vention. Even then, a user may impair playing an augmented image of a real the road, the real traffic experiences are the vehicle’s performance by trying to road. It’s tough to test whether a cam- supplemented with test-track scenarios. take control of the vehicle unexpectedly. era could detect a moose on the road We conduct our scenario tests at the To find out how people react, we simu- in the real world—getting the moose to AstaZero Proving Ground, a large test late autonomy by hiding a professional cooperate would be tricky—but we can track partially owned by the Research driver in the back of the vehicle, thus test how well the cameras see the moose Institutes of Sweden. The test track giving the impression that the vehicle is by augmenting actual road footage with extends through wooded areas and a driving itself, most of the time. We call an image of a moose at whatever dis- section simulating a town. AstaZero can it the “Wizard of Oz” vehicle, because tance and angle we need. In contrast, be configured to tackle virtually any traf- like the famous wizard in the movie, we when we test the radar, we place the fic conditions we would be interested use misdirection to draw attention away radar in a room where we can partially in testing. from the “man behind the curtain,” as or entirely cover the radar with water We supplement such traffic testing the wizard describes himself. or snow and test whether it recognizes with increasingly sophisticated virtual It’s not an elaborate ruse—we hide the the blockage. simulations. At the same time, aug- actual driver behind some plywood. Per- Of course, we also test how these mented imagery could assist in testing haps surprisingly, the test subjects rarely sensors work together in the actual some corner cases. Using augmented question the backseat enclosure. When vehicle. We can operate the vehicle reality, for example, we can test how one of them does ask, we explain it away in a se lf-driving mode to observe how well a vehicle obeys U.S. traffic signs as a space to hold computers or other well it gathers and uses the sensor data. using a road in Sweden; all we have to equipment necessary for the prototype. We’re primarily concerned with under- do is superimpose those signs over the Satisfied, our test subjects can sit back standing how well the vehicle’s sensors Swedish ones. This approach can be and experience a “true” self-driving function, so we also collect sensor data even more helpful in testing dangerous car. In fact, they become so comfortable during manual driving sessions to see corner cases like driving near pedestri- they often get bored or even fall asleep— how well the vehicle detected its sur- ans at high speed. revealing that we can’t always rely on roundings. These driving tests also give Decision making must be evaluated drivers to react quickly if cars need them us an opportunity to determine how separately from perception. That is, to take over in a tricky situation. well the vehicle detects its own limita- rather than test whether the vehicle sees In time, as human supervision of the tions—for example, radar works well in the world properly, we judge how well vehicle decreases, the bigger challenge fog but lidar and cameras do not. The it works with the uncertain and incom- becomes showing that the vehicle can vehicle must recognize those limitations plete picture that the perception system safely drive—unsupervised—in any situ- and adjust accordingly. provides it. For example, a blind corner ation it may encounter. That means put- Then comes perception. In general, could be hiding a pedestrian, who’s lia- ting trust in the vehicle’s sensors after the best way to test how well sensors per- ble to step into the road just as the vehi- performing standalone sensor tests. form this job is by placing real vehicles cle approaches. The decision-making We can test cameras, for example, in in real traffic conditions, in both good system must perceive that obstructed

real driving conditions, but it’s just as and bad weather. For less common cor- sight line and take that limitation into (4) Zenuity

44 | mar 2018 | SPECTRUM.IEEE.ORG consideration by planning to slow down We’ve spent quite some time on the sequence of actions: It has to detect when it approaches the corner. Like any test track tackling the diverse challenges the problem, plan maneuvers to react human driver, the vehicle must know its of on-road objects. Even small things, with a minimum amount of risk, and own limitations. such as a rock or an exhaust pipe that’s carry out that plan using a secondary We’re also building and continuously suddenly fallen off another car, can dam- system. Similar redundancies must expanding an immense database of age a vehicle if it’s going fast enough. For be included for components like sen- scenarios to test the decision-making all of these objects, we need to be sure sors, control units, software, commu- system against any scenario we choose. the vehicle can detect them from far nication systems, and the mechanical Consider a self-driving vehicle in a lane enough away to brake or change lanes in systems, and they must all be tested adjacent to a large 18-wheeler traveling time. Our testing is ongoing; while we’ve thoroughly. slightly behind it. Ideally, the vehicle gotten good results for some obstruc- Even after all that, we need to verify will recognize that it is driving in the tions, others pose specific challenges. that the complete system in the real truck’s blind spot and adjust its position Tires in the road, for example, aren’t vehicle in real traffic operates safely. Car to decrease the chance of an accident. picked up by lidar or radar very well. For manufacturers and self-driving vehicle Our database of scenarios can expose the vehicle to react to them in time, we startups will deploy test fleets and driv- the vehicle’s decision-making process still need to improve its ability to detect ers for this final step. to any variety of scenarios involving them with cameras. Self-driving vehicles are on the way, lane changes, merges, or other traffic Using a divide-and-conquer approach and they will make roads safer and more conditions with different speeds, posi- gives us the ability to test how the sys- efficient. But don’t expect to see them tions, and distances between vehicles tem components work together. To ver- on streets soon. It will still take a while to observe what decisions the vehicle ify the complete system means running to verify every corner case. Once a vehi- makes. Currently, our vehicles can han- countless simulations of various combi- cle has been verified for a specific sce- dle lane changes quite well, though we nations of traffic situations and intro- nario, like downtown New York City in still require them to keep a greater dis- duced failures. July, it will take additional verification tance from the vehicles around them Of course, other companies are tack- to ensure it can handle the same area than a human driver would need. ling this problem in different ways. In under winter conditions, as well as in Last but not least, the car must be able our experience, older, bigger compa- downtown Shanghai, on country roads, to execute its driving plan. We need to nies are relying on brute-force methods. and so forth. know how the vehicle’s normal capacity However, we see value in being modular By focusing on the acceptable rather to steer and to brake might be limited and swapping out hardware as needed. than obsessing over perfection, and by by conditions on the road, such as ice. We also want to keep the driver involved breaking down the colossal number of We can rely, in part, on computer simu and learn how to build an autonomous safety verifications into manageable lations, thanks to accurate models of vehicle that is safe for users. tasks, we can make self-driving vehi- vehicle components. But we can’t model We can use these methods to test the cles a reality for many customers around everything; to test how the car handles redundancy of a fully self-driving vehi- the world. n a tire blowout or an unexpected pothole, cle. Suppose the vehicle’s brakes fail. ↗ Post your comments at https://spectrum.ieee.org/ we have to put it on the test track. The vehicle must carry out a complex autonomouscars0318

NOW YOU SEE IT: Ensuring that a self-driving car can recognize objects like a stalled car or a moose crossing the road is tough if you don’t have one lying around, but real footage can be augmented with images of these objects to train the car to spot them.

SPECTRUM.IEEE.ORG | mar 2018 | 45 11111111111111111111111111010001111100101010110010101110111111111111111111111111 11111111111111111111111111100111100101001010100010100110111111111111111111111111 11111111111111111111111100001101011001010101000110101101111111111111111111111111 11111111111111111111111101101101000011101111111010011011111111111111111111111111 11111111111111111111111100100011101000110111101110100010111111111111111111111111 11111111111111111111111111100001011101000010010001110100111111111111111111111111 11111111111111111111111100010001101000001000101101011001111111111111111111111111 11111111111111111111111111101001010111010011110111110011111111111111111111111111 11111111111111111111111110011110100011111011010111010011111111111111111111111111 11111111111111111111111111101011001101000010101000001001111111111111111111111111 11111111111111111111111111010110010111001000000110011110111111111111111111111111 10010010101110110010001100001000001100000100010110001101000100100101011111000000 01100111001010111111011110100000000000000000000100100000101010010011010000110011 11001001101011101010010000101001101000000000101001001001100100100101000110010010 11101001101100110001011101000000100000000000100001000000111110100010001111000001 11101010000001111101110000000001010000001001010001100000101001010100111000001111Computing 01010101000111011001111111110100100000000100000000010000001010110100000100001101With 00001100111010111110100000011000000000011000100000010100111000111011111100001010Randomness 00111110010011101011100100101000001010000000110000010100111010110101011111101000• • • • • • • 01111111101111111110100000000010000000000100001000100000101000001011010000001011Stochastic computing, 11011111111011000101111010000101101100001000000100101001001010110100111101011101 a 50-year-old idea, 00100110001111100010001100111001000100000100110101001100110000100010011000000010 01010001110001111110100110100000000101000000000100000010001110010110011101110001is set for 10001000111011011011010001001010000011000000000000000100010011000011111001001011a comeback 11101011101010011111111001000000011100001000000000101100000101000010101001101000 01010010101000001100111000000000000001000000000000100110001100101110100000100010 01001010010111011111101010000000100000001000010001000000110111000011010010111101 11111111111111111111111111100100110100111100010110111101111111111111111111111111 11111111111111111111111111010000010110010001110001100110111111111111111111111111 11111111111111111111111101011000111000101001010101011111111111111111111111111111 11111111111111111111111101111110000101101101011100100011111111111111111111111111 11111111111111111111111100011000000100111000010111010110111111111111111111111111 11111111111111111111111111111111011111101001000001011001111111111111111111111111 11111111111111111111111101101001000111010101010101100001111111111111111111111111By Armin Alaghi & John P. Hayes 11111111111111111111111110010010111100111100000000101011111111111111111111111111 11111111111111111111111101001111011011001010110111001000111111111111111111111111 11111111111111111111111101011100110010011111110011100111111111111111111111111111 11111111111111111111111111110001100000100010000110101110111111111111111111111111 11111111111111111111111111010001111100101010110010101110111111111111111111111111 11111111111111111111111111100111100101001010100010100110111111111111111111111111 11111111111111111111111100001101011001010101000110101101111111111111111111111111 11111111111111111111111101101101000011101111111010011011111111111111111111111111 11111111111111111111111100100011101000110111101110100010111111111111111111111111 11111111111111111111111111100001011101000010010001110100111111111111111111111111 11111111111111111111111100010001101000001000101101011001111111111111111111111111 11111111111111111111111111101001010111010011110111110011111111111111111111111111 11111111111111111111111110011110100011111011010111010011111111111111111111111111 11111111111111111111111111101011001101000010101000001001111111111111111111111111 11111111111111111111111111010110010111001000000110011110111111111111111111111111 10010010101110110010001100001000001100000100010110001101000100100101011111000000 01100111001010111111011110100000000000000000000100100000101010010011010000110011 11001001101011101010010000101001101000000000101001001001100100100101000110010010 11101001101100110001011101000000100000000000100001000000111110100010001111000001 SPECTRUM. 11101010000001111101110000000001010000001001010001100000101001010100111000001111IEEE.ORG mar 2018 01010101000111011001111111110100100000000100000000010000001010110100000100001101 0000110011101011111010000001100000000001100010000001010011100011101111110000101047 00111110010011101011100100101000001010000000110000010100111010110101011111101000 01111111101111111110100000000010000000000100001000100000101000001011010000001011 11011111111011000101111010000101101100001000000100101001001010110100111101011101 00100110001111100010001100111001000100000100110101001100110000100010011000000010 01010001110001111110100110100000000101000000000100000010001110010110011101110001 10001000111011011011010001001010000011000000000000000100010011000011111001001011 11101011101010011111111001000000011100001000000000101100000101000010101001101000 01010010101000001100111000000000000001000000000000100110001100101110100000100010 01001010010111011111101010000000100000001000010001000000110111000011010010111101 11111111111111111111111111100100110100111100010110111101111111111111111111111111 11111111111111111111111111010000010110010001110001100110111111111111111111111111 11111111111111111111111101011000111000101001010101011111111111111111111111111111 11111111111111111111111101111110000101101101011100100011111111111111111111111111 11111111111111111111111100011000000100111000010111010110111111111111111111111111 11111111111111111111111111111111011111101001000001011001111111111111111111111111 11111111111111111111111101101001000111010101010101100001111111111111111111111111By Armin Alaghi & John P. Hayes 11111111111111111111111110010010111100111100000000101011111111111111111111111111 11111111111111111111111101001111011011001010110111001000111111111111111111111111 11111111111111111111111101011100110010011111110011100111111111111111111111111111 11111111111111111111111111110001100000100010000110101110111111111111111111111111 n electronics, the past half and machine-learning circuits—to give a couple of applica- century has been a steady tions we’ve investigated—which is why we believe stochas- march away from analog tic computing is set for a renaissance. and toward digital. Tele- phony, music recording and • • • • • • • playback, cameras, and radio Stochastic computing begins with a counterin- and television broadcasting tuitive premise—that you should first convert the num- have all followed the lead of bers you need to process into long streams of random computing, which had largely binary digits where the probability of finding a 1 in any gone digital by the middle of given position equals the value you’re encoding. Although the 20th century. Yet many of these long streams are clearly digital, they mimic a key the signals that computers— aspect of analog numbers: A minor error somewhere in and our brains—process are the bitstream does not significantly affect the outcome. analog. And analog has some And, best of all, performing basic arithmetic operations inherent advantages: If an analog signal contains small errors, on these bitstreams, long though they may be, is simple it typically won’t really matter. Nobody cares, for example, if and highly energy efficient. It’s also worth noting that the a musical note in a recorded symphony is a smidgen louder human nervous system transfers information by means or softer than it should actually be. Nor is anyone bothered of sequences of neural impulses that strongly resemble if a brightI area in an image is ever so slightly lighter than these stochastic bitstreams. reality. Human hearing and vision aren’t sensitive enough Consider a basic problem: Suppose you’re designing a light to register those subtle differences anyway. dimmer with two separate controls, each of which outputs a In many instances, there’s no fundamental need for elec- digital value representing a fraction between 0 and 1. If one tronic circuitry to first convert such analog quantities into control is fully turned on but the other is at, say, 0.5, you want binary numbers for processing in precise and perfectly repeat- the light to be at 50 percent brightness. But if both controls able ways. And if you could minimize those analog-to-digital are set to 0.5, you want the light to run at 25 percent bright- conversions, you’d save a considerable amount of energy ness, and so forth. That is, you want the output to reflect the right there. If you could figure out how to process the ana- value of the two control settings multiplied together. log signals in an energy-conserving fashion, you’ll be even You could, of course, achieve this using a microprocessor further ahead. This feature would be especially important to carry out the multiplication. What if, instead, the output for situations in which power is very scarce, such as for bio- of your two controllers was transformed electronically into medical implants intended to restore hearing or eyesight. a random series of 0 or 1 values, where the probability of a 1 Yet the benefits of digital over analog are undeniable, appearing at any given position in this stream of bits encodes which is why you see digital computers so often used to the value at hand? For example, the number 0.5 can be rep- process signals with much more exactitude—and using resented by a bitstream in which a 1 appears 50 percent of much more energy—than is really required. An interesting the time, but at random points. Elsewhere in the stream, the and unconventional compromise is a method called sto- bits have a value of 0. chastic computing, which processes analog probabilities Why go through the trouble of converting the number like by means of digital circuits. This largely forgotten techthis? Because basic arithmetic operations on such bitstreams nique could significantly improve future retinal implants are remarkably easy to accomplish.

Conventional binary number Stochastic bitstreams (Range 0 to 255) (Range 0 to 1) 128s 64s 32s 16s 8s 4s 2s 1s place place place place place place place place

1 0 0 0 1 0 1 1 1 0 0 0 0 0 1 0 = 2/8 or 0.25

Decimal equivalent Decimal equivalent 1 0 1 1 1 0 1 1 = 6/8 or 0.75 128 + 0 + 0 + 0 + 8 + 0 + 2 + 1 = 139

BY THE NUMBERS: Conventional binary numbers, just like the decimal numbers in everyday use, rely on the concept of place value [left]. Stochastic bitstreams don’t use place value; the value they represent is determined by how often 1s appear [right].

48 | mar 2018 | SPECTRUM.IEEE.ORG Consider the multiplication you need to set the brightness this sampling is again a very rudimentary one, called a multi of the light. One of the rules of probability theory states plexer. With it, addition becomes very easy. that the probability of two independent events occurring Similarly simple circuits can carry out other arithmetic simultaneously is the product of the probabilities of the operations on these bitstreams. In contrast, conventional individual events. That just makes sense. If you flip a penny, digital circuits require hundreds if not thousands of tran the probability that it will land on heads is 50 percent (0.5). sistors to perform arithmetic, depending on the precision It’s the same if you flip a dime. And if you flip both a penny required of the results. So stochastic computing offers a way and a dime at the same time, the probability that both will to do some quite involved mathematical manipulations using land on heads is the product of the individual probabili surprisingly little power. ties, 0.5 x 0.5 or 0.25, which is to say 25 percent. Because of this property, you can multiply two numbers encoded • • • • • • • into bitstreams as probabilities remarkably easily, using Engineers welcomed stochastic computing just an AND gate. when it was first developed in the 1960s because it allowed An AND gate is a digital circuit with two inputs and one out them to perform complicated mathematical functions with put that gives a 1 only if both inputs are 1. It consists of just just a few transistors or logic gates, which at the time were a few transistors and requires very little energy to operate. rather costly. But transistors soon became much cheaper

(4/8 = 1/2) 0 1 1 0 1 0 1 0 (3/8) 0 0 1 0 1 0 1 0 (6/8 = 3/4) AND 1 0 1 1 1 0 1 1

MANY TIMES BETTER: Using stochastic bitstreams, multiplication can be carried out with a single AND gate. Here two bitstreams, representing 1/2 and 3/4, provide the inputs. The output has 1s in three of eight positions, meaning that it represents a value of 3/8—the product of the two inputs.

Being able to do multiplications with it—rather than, say, pro to make, and the attraction of stochastic computing quickly gramming a microprocessor that contains thousands if not faded, as did solutions that involved just analog circuitry. millions of transistors—results in enormous energy savings. The now-common forms of digital circuitry took off because How about addition? Again, suppose we have two bit they offered much better speed, performance, and flexibility. streams representing two numbers. Let’s call the probabili But an important exception to that rule appeared in the ties of finding a 1 at any given point in those two bitstreams, mid-2000s, shortly after a new error-detection and error- respectively, p1 and p2. If one of these bitstreams has a value correction scheme, low-density parity check (LDPC), started of 1 in 60 percent of the bit positions, for example, then coming into widespread use. Discovered in the 1960s, LDPC the value it represents is 0.6. If the other has a value of 1 codes are now used everywhere in communication systems, in 90 percent of the positions, the value it represents is including Wi-Fi networks. Decoding LDPC codes can be a 0.9. We want to generate a bitstream denoting the sum tricky business, however. But because the decoding involves of those two values, p1 + p2. Remember that p1 and p2, like probabilistic algorithms, it can be implemented using rela all probabilities, must always lie between 0 (something is tively simple stochastic computing circuits. impossible) and 1 (something is certain). But p1 + p2 could The success of stochastic circuits in that context, and the lie anywhere between 0 and 2, and anything greater than fact that controlling power use has now become one of the 1 can’t be represented as a probability and thus can’t be biggest challenges facing chip designers, prompted us and encoded as a bitstream. other researchers to revisit stochastic computing several To sidestep this obstacle, simply divide the quantity of years ago. We wanted to see what else it could do in the mod interest (p1 + p2) by 2. That value can then be represented by ern electronic era. a bitstream, one that is easy to compute: Each bit in it is just It turns out there is quite a lot. Apart from saving power, a random sample from the two input bitstreams. Half the stochastic computing also offers a unique property known time, a bit sampled from the first input is transferred to the as progressive precision. That’s because, with this technique, output; otherwise a bit from the second input is used, effec the precision of the calculations depends on the length of tively averaging the two inputs. The circuit that accomplishes the bitstream you use. For example, suppose you’re using

SPECTRUM.IEEE.ORG | mar 2018 | 49 0110101010010111 to represent the fraction 9/16 (nine 1s in 16 possible bit positions). With stochastic computing, the leftmost digits are processed first, and all bits have equal significance or weight. If you look at the first eight bits of this example, 01101010, you get the number 4/8, which is a low-prec ision estimate of the 0 1 1 0 0 0 1 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1 value represented by the longer sequence.

The circuits that are used to process BITSTREAM BRAINS: Neural signals resemble bitstreams in that frequent spikes indicate high stochastic bitstreams act as though they values of neural activity, just as frequent 1s in a bitstream indicate high values for the number are computing with the most significant that it represents. digits of the number first. Conventional digital circuits—or paper-and-pencil calculations—work the other way, from the least to the most sig- of the binary digits in a bitstream to flip, the number repre- nificant digits. When a normal computer adds two binary sented by that bitstream won’t change significantly: Often numbers together, the first bits computed don’t provide any there will be as many 1s that change to 0s as there are 0s sort of early approximation of the overall result. that change to 1s, so the noise will just average out over time. Stochastic computing circuits, on the other hand, do exactly These similarities with biological systems weren’t lost on that: Their progressive-precision property means that the us when we began our research. And we had them in mind answer is pretty good at the start and tends to get increas- when we began looking into an exciting new application for ingly precise as more and more bits flow through the circuit. stochastic computing—processing signals in retinal implants. So a computation can be ended as soon as enough bits have Retinal implants are intended to restore sight to people emerged in the results, leading to significant energy savings. with severe macular degeneration, retinitis pigmentosa, and How many bits is enough? That depends on the application, other degenerative diseases of the retina. Although using and those that demand high precision will, of course, require electronics to restore lost vision is an old idea, the actual longer bitstreams—perhaps hundreds or even thousands of bits. clinical use of retinal implants is less than a decade old, and There are limits to the precision you can achieve in practice, it’s been attempted with comparatively few patients because though. That’s because to represent an n-bit binary number, the technology remains so rudimentary. stochastic computing requires the length of the bitstream to Most retinal implants capture and process images outside be at least 2n. Take the case of 8-bit numbers, of which there the eye using a camera and a digital computer. That’s pretty are 256 possible values. Suppose you wanted to represent the clunky. And it gives patients an odd sense when they move probability 1/256 with a bitstream. You’d need a bitstream that their eyes and find that the image projected on their retinas is at the very least 256 bits long—otherwise there wouldn’t be doesn’t move in the way their brains expect. What you really a place for a lone 1 in a sea of 0s. Similarly, to represent 9-bit want, of course, is for the image sensing and processing to numbers, you’d need streams of at least 512 bits. For 10-bit take place inside the eye. One hurdle to accomplishing this is numbers, the requirement would be for 1,024 bits, and so that there’s little power available inside the eye to operate the on. Clearly, the numbers get large fast. Achieving even what electronics—the only power sources available are tiny induc- is known in computer programming circles as single preci- tive pick-up coils or photovoltaic cells. And you need rela- sion (32 bits) would be nearly impossible, because it would tively large amounts of power to sense and process images require streams of billions of bits to be manipulated. using conventional digital circuits. Even if a source of suffi- cient power were available, using it would still be problematic • • • • • • • because excessive power dissipation can harm eye tissues, LOw in precision as it is, stochastic computing is curi- which can tolerate only a few degrees of temperature rise. ously similar to what goes on inside our brains. Our neural For these reasons, we figured that the simplicity and effi- pathways encode their signals primarily by the rate or fre- ciency of stochastic computing could make a big difference. To quency of sharp electrical pulses or “spikes.” When those test this idea, we conducted a little experiment. We designed spikes are few and far between, the activity of the neural several stochastic image-processing circuits, including one that pathway is said to be low; when they occur frequently, the detects edges in images. (Edge detection improves contrast, activity level is high. Similarly, when the 1s in a bitstream making objects easier to perceive.) Not surprisingly, the sto- are few and far between, the stream corresponds to a low chastic circuit we designed for this purpose is much simpler number; when they are common, it encodes a high number. and more efficient in its use of power than the kinds of digital Also, stochastic computing circuits, like many biological sys- circuits typically used for edge detection. tems, are resilient in the face of many kinds of disturbances. Another biologically inspired application of stochastic com- If, for example, a source of environmental noise causes some puting is in artificial neural networks, which lie at the heart

50 | mar 2018 | SPECTRUM.IEEE.ORG of many of today’s smart systems. We explored this application recently using an image sensor connected to such a neural network, one configured to recognize digits after it has been trained to do so— meaning that its many adjust- able parameters have been set at values that allow it to classify the images presented to it as a specific digit. Neu- ral networks are arranged in a series of layers of artificial neurons, where the output of one layer serves as the input to the next. In our experiments, we replaced the first ALWAYS ON EDGE: Edge detection is commonly used in image processing. Here, an edge- detection algorithm that uses conventional binary numbers [top row] is compared with one that processing layer of our net- uses stochastic bitstreams [bottom row]. The stochastic results hold up much better as the work with stochastic circuitry. bit-error rate is increased from 0.1 percent [far left] to 0.5 percent [middle left] to 1.0 percent Although the stochastic cir- [middle right] and finally to 2.0 percent [far right]. cuitry sometimes gave inac- curate arithmetic results, it did not matter because neural it will serve as a multiplier, say, or an adder. We found that networks can learn to tolerate such errors. So we just retrained you can go the other way, too. You can start with the desired our neural network to deal with the stochastic errors. In this function and perform those mathematical transformations way, we could reduce the energy used in the first layer of the in reverse to deduce the circuit needed. network by a factor of 10, while pretty much preserving the Based on that observation, we developed a method that original level of accuracy in digit classification. enabled us to design efficient stochastic computing circuits for image processing, including one that could carry out a common image-processing function called gamma correc- ne of the things holding tion. (Gamma correction is used to account for the insensi- stochastic computing back has tivity of the human eye to small differences in brightness in been the lack of any compre- lighter areas of an image.) With this strategy, we were able hensive design methodology. to design a small (eight gate) circuit that implements the Sure, it’s easy enough to design gamma-correction function. circuits for simple arithmetic Efficient as they are, stochastic circuits can be made even operations such as multiplica- more so when combined with a power-reduction technique tion and addition, but when the known as voltage scaling. That’s basically a highfalutin way target function is more compli- of saying that you dial the voltage way down to save energy cated, engineers have long been at the cost of creating occasional errors. That’s not much of without a good road map. a problem for stochastic circuits, which can work acceptably A decade ago, Weikang Qian and Marc Riedel, of the Univer- well at voltages that would be too low for conventional ones. Osity of Minnesota, devised a novel technique to solve this prob- For example, the gamma-correction circuit we built can tol- lem. Building on their work, we recently discovered another erate a voltage reduction up to 40 percent, from 1 volt down approach to designing stochastic computing circuits. It begins to 0.6 V, with no loss of accuracy. And unlike conventional with the observation that a stochastic circuit corresponds to a binary circuits, which fail catastrophically when the volt- Boolean function. AND, OR, NAND, and NOR are all examples age scaling is too aggressive, stochastic circuits continue to of Boolean functions. More generally, they are defined as a operate, albeit with less precision, as the voltage is reduced. mathematical function that takes some number of different While our examination of circuits for retinal implants and inputs (each of which can be 0 or 1) and produces one output, neural networks makes us very optimistic about the pros- which, depending on the input values, will be 0 or 1. pects for stochastic computing, we still haven’t discovered Suitable mathematical transformations applied to that the real killer app for this approach. It may be 50 years old, Boolean function—ones similar to those used to determine, but stochastic computing, in our view, is still in its infancy. ■ for example, the frequency content of audio signals—reveal armin alaghi armin how the stochastic circuit will operate on bitstreams, whether ↗ Post your comments at https://spectrum.ieee.org/stochastic0318

SPECTRUM.IEEE.ORG | mar 2018 | 51 Adhesive quantum-dot TVs ters. But, unlike photo-emissive QDs, Academy continued from page 33 they also don’t need a backlight. Because each subpixel is addressable—it’s turned high viscosity researchers, including Japanese ink- “on” by stimulating it with electrons—the maker DIC Corp., are experimenting display wastes no energy producing pho- with a variety of printing techniques, tons in the backlight, many of which are invariably wasted. This educational video explains including inkjet and transfer printing. This educational video explains We expect to see some type of printed Electro-emissive quantum-dot dis- thethe benefitsbenefits ofof utilizingutilizing highhigh displays begin to hit the market in late plays have the potential to completely viscosityviscosity andand non-dripnon-drip 2019 or 2020. The materials are essen- disrupt the display industry over the adhesiveadhesive formulationsformulations forfor tially ready to go, but display manufac- next decade, potentially providing the turers are not quite ready to roll out new thinness and flexibility of OLED displays bonding vertical substrates production processes. but with the cost, color, brightness, and andand gapgap filling.filling. What comes after photo-emissive QD reliability benefits of quantum dots [see TVs? It may well be an entirely different “Electro-Emissive QD TV”]. They’ll be approach—one that combines quantum highly efficient and have wide viewing Are high viscosity dots with micro-LED technology [see angles with pure colors. They’ll also have adhesive systems “Micro-LED TV With QDs”]. A micro- beautiful black levels: When a color isn’t right for your LED display is quite similar to that of needed, the dot that produces it will be application? the jumbotron at your local football sta- completely off, with no possibility of dium, in which each subpixel is a red, light leakage. We’ll be able to use low- green, or blue LED. Now imagine the cost printing techniques to produce entire display shrunk down to the size of them, so there’s no reason why they a TV. That’s similar to the way an OLED should be costly. And because they are display works, but because micro-LEDs made with inorganic materials, rather use inorganic materials, they are more than all-organic materials, they will have reliable. They can also produce brighter longer lifetimes without a degradation images and have a faster response time. in performance. Both Apple and Oculus VR have Don’t expect to see electro-emissive acquired micro-LED companies and have quantum-dot displays in stores in the been working to bring the technology to next couple of years—they’re still in the the mass market, but cost is still an issue. early phases of development. However, It turns out that it’s really hard to get a they’re moving along quickly: Chinese reasonable manufacturing yield while display maker BOE Technology Group trying to fit millions of supertiny LED pix- Co. demonstrated the technology pub- els together with near-perfect accuracy. licly for the first time in 2017. The first Photo-emissive QDs can help solve commercial displays using the technol- that problem. It’s much easier to make ogy should start rolling out of factories a single-color micro-LED display than a in the next five years. three-color one. Display makers could start with a blue-only micro-LED array All of this technological ferment is being and then pattern red and green quan- driven, in part, by a recent change in tum dots on top. This type of micro- display standards. In the past, televi- Gap Filling NON-DRIP LED is likely to come to market within sion standards have restricted just how a few years. closely you could match the images you were seeing on the screen with Photo-emissive QD TVs will be only how they appeared in real life. Even one step in the evolution of quantum- the HDTV standard, developed in the dot televisions. Next will come electro- 1980s, didn’t try to account for all the emissive QD TVs. colors in the natural world. Rather, its In this system, quantum dots are stim- creators considered what colors could ulated to emit photons by electrons, be produced given the best available Hackensack, NJ 07601 USA instead of other photons. Like photo- phosphor materials that could be used +1.201.343.8983 • mainmasterbond.com emissive QDs, they don’t need color fil- in a cathode-ray tube. www.masterbond.com Today’s video standards groups are approaching the problem by asking a much more important question: What’s the best color experience for the human visual system? This approach led to BT.2020, an Inter- national Telecommunications Union (ITU) standard, recommended in 2012 and then approved in 2015. BT.2020’s WEBINARS color palette covers 99.8 percent of the colors reflected by the natural world— Siemens PLM On-Demand Webinar: The Importance that’s nearly 60 percent of the spectrum Software of Reducing Dust Accumulation in visible to the human eye. It’s already Electronics Systems been embraced by Blu-ray Disc manufacturers, and NHK (Japan Broadcasting Corp.) has announced that it intends to Keysight On-Demand Webinar: Overcome broadcast the 2020 Summer Olympics Technologies, Inc. Critical Power Consumption Testing in this format. Challenges Televisions built to the HDTV standard can reproduce only 58 percent of the BT.2020 range of colors. LCD-based National On-Demand Webinar: Save Time and Ultra HD TVs (without quantum dots) Instruments Money with Unit Testing do better, most covering around 70 percent of the colors, while OLED TVs today are up to around 74 percent. Photo- enhanced quantum-dot displays on the market can handle 85 to 90 percent of WHITE PAPERS the color palette specified by the stan- Spruce Up Your Walls and Your Test dard. The photo-emissive QD displays Keysight under development are at 93.3 percent, Technologies, Inc. Asset Performance – Exemplary and electro-emissive QD technology, at performance from your test assets ensures the moment, is at around 90 percent. In the best performance for your device under plain language, these TVs have the pos- test. sibility, at least, of being spectacularly more engaging and impressive than even the best OLED televisions available today, National The Test Implications of Packaging and at a lower cost. Instruments Innovation – As the semiconductor As a result of the pull on the standards industry strives to meet performance, size, front and the push by quantum-dot and cost demands, learn how automated researchers and TV display manufac- test strategies must evolve to keep pace. turers, we are about to see a revolution in television displays. Finally, after years of fantasizing about low-cost, foldable, and Maplesoft Calculation Management Done Right – rollable TVs and even TVs-as-wallpaper Calculation Management is fundamental to in the home of the future, we are less reducing errors and creating a streamlined than a decade away from having those process across an organization. systems on our walls. And with essentially all the colors the eye can see anywhere we want them, we’ll be thinking less about how our screens enable us to watch things and more about what we actually want to watch. n Find out more!

↗ Post your comments at https://spectrum.ieee.org/ quantumdot0318 spectrum.ieee.org/webinars spectrum.ieee.org/whitepapers The George Washington University invites applications for a non-tenure- accruing contract faculty position at the rank of Assistant/Associate/ Belk-Woodward Distinguished Professor of Engineering Full Professor of Practice in the William States Lee College of Engineering Department of Electrical & Computer The William States Lee College of Engineering at the University of Engineering (ECE) to begin in Fall 2018. Information about the North Carolina at Charlotte invites applications for the Belk-Woodward department is available at http://www.ece.seas.gwu.edu/. Distinguished Professor in Engineering. Income from a $1M endowment is available to the Belk-Woodward Professor as supplemental support to their Basic Qualifications: Applicants must have at least an MS degree in research and educational programs. An experienced, dynamic candidate who can collaboratively lead the College’s pursuit of excellence in funded Electrical Engineering, Computer Engineering, or related field by time of research is desired. The successful candidate will have credentials and appointment, an ability to teach undergraduate courses, and at least 10 experience appropriate for appointment at the rank of Professor in one of years of practical experience (5 years if having PhD). Applicants must the five departments in the College of Engineering (Civil and Environmental possess hands-on skills in one or more of the following electrical and Engineering, Electrical and Computer Engineering, Engineering Technology and Construction Management, Mechanical Engineering and Engineering computer engineering-related topics: embedded systems, computer Science, and Systems Engineering and Engineering Management). organization, digital design, FPGAs, device and analog electronics, Candidates should have an outstanding record of scholarly accomplishments computer interfacing with various sensors and actuators, and a and funded research, a demonstrated ability to work across disciplines to build and lead a collaborative research enterprise, and a strategic vision for a general awareness of the wide spectrum of concepts and other relevant transformative research area to be housed within the College of Engineering. technologies within an ECE environment. Applications must be submitted electronically at https://jobs.uncc.edu To view full announcement and apply, go to http://www.gwu.jobs/ (Position # 004504). Candidates should provide a cover letter, a detailed CV, and names and contact information of at least three references. Review of postings/48563 and upload (i) a cover letter, (ii) detailed CV/resume, applications will begin immediately and continue until the position is filled. (iii) a concise statement of teaching and relevant experience, and (iv) full The Williams States Lee College of Engineering has approximately 4,000 contact information for four professional references. Please indicate your students and prides itself on its excellence in undergraduate and graduate primary area(s) of expertise and interest and desired professorial rank. education. It is home to several interdisciplinary research centers: the Energy Production Infrastructure Center (EPIC), the Center for Biomedical Only complete applications will be considered. Offers are contingent on Engineering Systems (CBES), the Center for Precision Metrology (CPM), satisfactory outcome of a standard background screening. the Infrastructure, Design, Environment and Sustainability Center (IDEAS), the NC Motorsports and Automotive Research Center (NCMARC), the Asset George Washington University is an Equal Employment Opportunity/Affirmative and Infrastructure Management (AIM) Center, and the Center for Advanced Action employer that does not unlawfully discriminate in any of it programs or Multimodal Mobility Solutions and Education (CAMMSE). For additional activities on the basis of race, color, religion, sex, national origin, age, disability, information see http://coe.uncc.edu. veteran status, sexual orientation, gender identity or expression, or any other basis UNC Charlotte is an Equal Opportunity, Affirmative Action employer and an ADVANCE institution and strongly encourages applications from all underrepresented groups. prohibited by applicable law.

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54 | Mar 2018 | SPECTRUM.IEEE.ORG Sung Kah Kay Assistant Professor in All Areas of Computer Science The Department of Computer Science at the National CANADA RESEARCH CHAIR POSITION University of Singapore (NUS) invites applications for the FACULTY OF ENGINEERING AND APPLIED SCIENCE Sung Kah Kay Assistant Professorship. Applicants can be Applications are invited for a Canada Research Chair Position in the Faculty of Engineering and in any area of computer science. This prestigious chair was set up in memory of the late Assistant Applied Science at the University of Regina. Professor Sung Kah Kay. Candidates should be early in their academic careers and yet demonstrate Canada Research Chair Tier II – Power Systems Control outstanding research potential, and strong commitment to teaching. and Protection For full details about this, and other career The Department enjoys ample research funding, moderate teaching loads, excellent facilities, and opportunities, and our application process, please visit extensive international collaborations. We have a full range of faculty covering all major research our website at http://www.uregina.ca/hr/careers areas in computer science and boasts a thriving PhD program that attracts the brightest students All qualified candidates are encouraged to apply; however, Canadians and permanent residents will be given priority. from the region and beyond. More information is available at www.comp.nus.edu.sg/careers The University of Regina is committed to achieving a representative workforce and qualified diversity group NUS is an equal opportunity employer that offers highly competitive salaries, and is situated in members are encouraged to self identify on their applications. Singapore, an English-speaking cosmopolitan city that is a melting pot of many cultures, both the east and the west. Singapore offers high-quality education and healthcare at all levels, as well as very low tax rates. Application Details: NAU’s School of Informatics, Computing and Cyber Systems invites applications to support a dual • Submit the following documents (in a single PDF) online via: https://faces.comp.nus.edu.sg degree program with the Chongqing University -A cover letter that indicates the position applied for and the main research interests of Posts and Telecommunications. Two positions -Curriculum Vitae begin August 2018. Minimum qualifications are a Bachelor’s degree and a Master’s or Ph.D. degree -A teaching statement in Electrical Engineering, Computer Engineering, or -A research statement related field earned before start date. An Assistant • Provide the contact information of 3 referees when submitting your online application, or, Professor of Practice position requires five years arrange for at least 3 references to be sent directly to [email protected] of professional experience and rotates between Chongqing and Flagstaff. A Lecturer position is • Application reviews will commence immediately and continue until the position is filled. based in Flagstaff. To submit an application, see the • If you have further enquiries, please contact the Search Committee Chair, Weng-Fai Wong, complete postings (#603442, #603191) at https:// at [email protected] nau.edu/Human-Resources/Careers/.

University College Dublin’s School of Electrical & Electronic Toyota Technological Institute has one opening Engineering has a long and distinguished record of excellence for “Principal Professor” positions in its School in education and research. The School has an international of Engineering. For more information, please track record of research achievement across major fields within refer to the following website: http://www. toyota-ti.ac.jp/english/employment/index.html. the discipline, including physical layer communications and Research fields: Science and technology for advanced integrated circuits, electrical power systems, optimisation and instrumentation and/or information processing control, and biomedical engineering (http://www.ucd.ie/eleceng). Examples: New devices and systems for advanced information processing, Faculty members, including six IEEE Fellows, are active in a number of Ireland’s communication, and/or sensing; Leading instrumentation technologies for ultra- strategic research and technology centres, including CONNECT, I-FORM, LERO sensitive measurements and/or bio-medical studies and diagnosis; Science and and MCCI. The School is committed to the highest standards of undergraduate technology of cyber-physical systems. and postgraduate teaching, learning and student development within a research- Qualifications: A successful candidate must have a Ph. D. degree or the equivalent informed environment. in a relevant field; he/she must possess outstanding competence to promote world-class research program(s) as well as to conduct excellent teaching and Applications are invited for faculty positions in the following areas: research supervision for graduate and undergraduate students, so as to fulfill his/ 1. Integrated Circuit Design (with expertise in one or more of the following: her mission as a superb leader in research and education. monolithic Radio Frequency (RF), Analogue, and Mixed-Signal Circuit Design); and Number of Positions Available: One Start date: April 1, 2019 or on the date of the earliest convenience 2. Cyber-Physical Systems (with expertise in one or more of the following: Optimisation, Control, Decision Science, Stochastic Processes, Machine Learning). Documents: (1) A curriculum vitae Candidates should have outstanding records of research accomplishment in (2) A list of publications fundamental scientific areas underpinning Electronic Engineering, be qualified to (3) Copies of 5 representative papers deliver high quality research-informed teaching to doctoral level, and be capable of (4) An outline of research and educational accomplishments (about 3-pages) contributing to Bachelors and Masters degree programmes in Electronic Engineering. (5) A future plan of educational and research activities (about 3- pages) (6) Names of two references, including phone numbers and e-mail addresses Appointees will be located within the School of Electrical & Electronic Engineering (7) An application form (available on our website) and will be expected to develop into leading figures within Ireland’s Engineering Deadline: May 15, 2018 community, building up and sustaining internationally important research teams, Inquiries: Search Committee Chair, Dr. Kazuo Hotate, Vice President & Professor and interacting with industrial partners and other disciplinary areas within and (Phone) +81-52-809-1821 (E-mail) [email protected] outside the university. The above documentation should be sent to: Lecturer/Assistant Professor (above the bar) Salary Scale: €52,325–€82,267 per annum. Mr. Masashi Hisamoto Toyota Technological Institute Closing date: 16 April 2018 2-12-1, Hisakata, Tempaku-ku, Nagoya, 468-8511 Japan Full details can be found at https://www.ucd.ie/workatucd/ (Job Refs 010026, 010027). Please write “Application for Principal Professor” on the envelope. University College Dublin is an Equal Opportunity Employer The application documents will not be returned.

SPECTRUM.IEEE.ORG | Mar 2018 | 55 past forward_by Allison Marsh

In 1996, John Deere introduced this “green eggs and ham” GPS receiver, which helped usher in Plowing the age of precision agriculture. Mounted on top of a tractor’s cab, it received signals from Global With Positioning System satellites and then fine-tuned the readings using a C-band antenna. Eventually, such receivers would guide autonomous tractors, enabling them to plow a field with centimeter Precision precision. The receiver had to be rugged as well, able to withstand lousy weather, temperatures from –20° to 45° C, vehicle vibration, and occasional incursions by rodents, birds, and other creatures. ■ ↗ For more on John Deere and precision agriculture, go to https://spectrum.ieee.org/ pastforward0318 nstitution I

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56 | Mar 2018 | SPECTRUM.IEEE.ORG Endless Possibilities ... and countless risks

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