ECE 2008 THE BRADLEY DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING This report was produced with funds from the Harry Lynde Bradley Foundation.

BEHIND THE COVER: The MANIAC Challenge, organ- ized by an ECE team, generated the first large multi-hop mo- bile ad hoc network in November 2007 (p. 9). This was one of many activities in the department related to networks — from cognitive radio to power distribution to gene networks. The underlying graphic is based on a work by abstract artist Ja’ Ski, called “Futuristic Network.” Cover illustration by Christina O’Connor. WHAT’S INSIDE FEATURES 4 Blackout Busters 6 Securing the Airwaves 9 Hunting in the Wild MANET 12 Shrinking Lab Equipment Onto a Chip 16 Space@VT RESEARCH

31 Research 34 Networking 32 VLSI & Design 35 Communications Automation 36 Electromagnetics 32 Computer 38 Systems 39 Power 33 Software & Machine 40 Signals, Systems Intelligence & Controls

UNDERGRADUATE RESEARCH 25 Undergraduate Reaching for the Edge of Space 35 Networks for the GPS-Challenged 41 Jumping Head First Into the Unknown

ECE PEOPLE 2 From the Department Head 3 From the Advisory Board Chair 26 Bradley Fellows 28 Bradley Scholars 42 Ph.D. Degrees Awarded 44 Honors & Achievements 46 Donors to ECE 48 ECE Faculty 49 ECE Industrial Advisory Board

Photography by Virginia Tech Visual Communications unless noted otherwise. Jim Stroup: pp. 2, 3, 4, 5, 6, 7, 8, 12, 13, 14, 15, 38, 39 John McCormick: pp. 21, 41, 43 Kim Peterson: p. 38

Produced by The Right Word Communications PERSPECTIVES from the Department Head s the world knows, 2007 was a tumul- Utah State, where he had served as department tuous time at Virginia Tech. Like the head and held an endowed chair. Majid Manteghi, rest of the university community, we an assistant professor in antennas and RF joined in ECE were affected by the horrible the faculty from UCLA. This spring, Marius Or- events of last April. All of us in the de- lowski accepted a position here as the VMEC Apartment mourn the senseless deaths of Chair in microelectronics. He came from Freescale and injuries to our students, faculty, friends, and Semiconducteur in France. neighbors. But it hasn’t changed who we are: a de- The new Center for Space Science and Engi- partment passionate about knowledge and educa- neering Research Center just completed building tion in electrical and computer engineering. our new HokieDARN radar station, that for the This year, many of our ECE alumni have re- first time enables continual mapping of the space connected with us, reminding us of our strengths weather plasma motions over the northern United and successes. Our alumni are a strong link to both States. This and our other space science activities the technology community and to communities are described beginning on page 16. around the world. Please keep in touch! Our opening stories describe work being From our alumni, we have heard that the Na- done in cognitive radio networks. This technol- tional Science Foundation (NSF) has honored ogy draws researchers from many areas and has be- three of our alumni with CAREER awards — its come a significant activity in our department. Two highest award for young faculty leaders. In 2007, of our student teams took top honors at the Soft- James S. Thorp Department Head Neil Patwari (BSEE ’97, MSEE ’99) earned an ware Defined Radio Forum’s 2007 Smart Radio award for his work at the University of Utah. The Design Challenge. prior year, two Ph.D. graduates, Robert Adams Notable faculty awards include Masoud Agah (’98) at the University of Kentucky and Greg Dur- (see p.13) and Jung-Min Park (see p.6) receiving gin (’00) at Georgia Tech both received CAREER NSF CAREER awards. G.Q. Lu’s development of awards. This past year, Durgin was also honored nanoTach was listed one of the 100 most techno- with Georgia Tech’s highest teaching award. logically significant products of 2007 by R&D We have a strong group of alumni who live Magazine. and work in Virginia. As the state’s largest and My many thanks to Dan Sable who has con- highest ranked ECE department, we take pride in tinued for a second term as the chair of the advi- the latest news that Virginia has the highest tech- sory board. Dan and the board have been nology worker density in the country and is the extremely helpful in supporting the initiative in fifth largest high-tech state. Most of these jobs re- space sciences. late directly to our field, involving computer sys- Last year I asked for help in identifying pho- tems design and service and engineering services. tos of W. A. Murray (1935-56) and B. M. Widener We continue to adapt to serve the needs of the re- (1956-58) to complete our wall of department gion and the field. We added three new faculty heads. I am happy to report we received the pho- members this year, but will be constrained with tos and the artist is painting both portraits. the institution of budget cuts that will limit our future hiring. In the fall, Tamal Bose joined ECE as the as- sociate director of @VT, coming from

2 from the Advisory Board Chair t is an honor and a privilege to have been re- of cognitive radio networks and development of elected as chair of ECE’s Industrial Advisory a credit-card sized gas chromatography platform. Board (IAB) for a second year. The events of CAREER awards are NSF’s most prestigious last April are still fresh in our memory. The award for creative junior faculty members consid- resulting challenges that they have brought ered to be future leaders in their academic fields. Ito the ECE department and the entire uni- ECE assistant professor Scott Bailey was the versity appeared at first to be insurmountable. We co-principal investigator of the NASA AIM Satel- mourn the loss of ECE student Henry Lee, and lite, which was launched April 25, 2007. He was our other friends and students who were killed. able to convince NASA at the last minute to place We are encouraged by the determination and heal- a logo on the rocket in memory of the Virginia ing of those who were injured. Our entire com- Tech victims. munity still is dealing with the emotional fallout. As alumni and members of the Industrial Ad- However, in the face of this adversity and the con- visory Board, it is in our own interest to see the tinuing emotional and financial burden that is ECE department prosper and gain greater reputa- being placed on Virginia Tech and the ECE de- tion. My vision for the IAB is to encourage an ac- partment, in fact, we have become stronger. tive role for the members in several ways: The Virginia Tech ECE department has truly 1. Alumni and IAB member companies can outstanding undergraduate and graduate programs encourage practical experience by sponsoring un- with excellent faculty world-renowned for teach- dergraduate and graduate student interns. ing and research. I can still remember 25 years ago 2. Alumni and IAB member companies can when Dusan Boroyevich and I were graduate stu- participate directly in the classroom through guest dents together taking the first course in Power lectures. Relating practical problems encountered Electronics offered by Fred Lee. “Dr. B.,” as the in industry to the classroom theory goes a long students call him, is now one of the most well re- way with student understanding of course mate- Dan Sable spected lecturers in the ECE department. Boroye- rial. Chair, ECE Advisory Board vich and Lee are now completing their 10th and 3. Alumni and IAB member companies can final year as a National Science Foundation (NSF) sponsor research in areas of most concern to them. Engineering Research Center (ERC). This puts 4. Alumni and IAB member companies can them into an extremely elite group of only six take an active role in being an advocate for the other universities in the country with graduating ECE department at the college and university NSF ERCs in the electronics area. level. The ECE department has been a traditional The list of ECE accomplishments in the past strength of the university. It is critical that it con- year continues. The recent Franklin Institute tinues to receive appropriate priority. Award to ECE Department Head Jim Thorp, and 5. Finally, alumni and IAB member compa- ECE University Distinguished Professor Emeritus nies can support the ECE department through Arun Phadke puts Virginia Tech ECE in a league generous financial donations. with Albert Einstein, , Orville The ECE department head, Jim Thorp, has Wright, and Marie and Pierre Curie. ECE gradu- demonstrated remarkable leadership in focusing ate students took top honors in the Inaugural the Department and the IAB fully supports his ef- Smart Radio Challenge at the 2007 Software De- forts. The university is fortunate to have person of fined Radio Forum conference in November. his stature, integrity, caliber, and vision as the ECE Tech was the only school with two teams among Department Head. the final 10 competitors. Great teaching, great research, great students, ECE assistant professors Jung-Min Park and great alumni, great leadership – what more can Masoud Agah were awarded NSF CAREER one ask for? Awards for their work on improving the security

3 Arun Phadke (left) and Jim Thorp (right).

Franklin Medal Winners, Arun Phadke & Jim Thorp

Today, their technology and BLACKOUT BUSTERS algorithms are ore than 30 years ago, Jim Thorp, ECE de- Curie, , and Jane Goodall. used to keep partment head, and Arun Phadke, a uni- Phadke and Thorp received the award for lights on around Mversity distinguished professor emeritus, “pioneering contribution to the development and first teamed up to fight power grid blackouts. application of microprocessor controllers in elec- the world, and Today, their technology and algorithms are used tric power systems.” Their work has made black- they have been to keep lights on around the world, and they have outs less frequent, less intense, and easier to been honored with the prestigious 2008 Benjamin recover from. honored with Franklin Medal in Electrical Engineering. Their partnership began in 1976 when Thorp the prestigious For 184 years, the Franklin Institute has was a professor at Cornell and took a sabbatical identified men and women from around the to study power systems at American Electric 2008 Benjamin world whose contributions have benefited soci- Power (AEP) in New York. There he met Phadke. Franklin Medal ety, advanced science, launched new fields of in- “We were working on introducing computer ap- quiry, and deepened the understanding of the plications into the power system,” Phadke recalls. in Electrical universe. Previous recipients include Albert Ein- “Jim had a background in controlling systems and Engineering. stein, , Max Planck, Enrico Fermi, we gave him an assignment in computer applica- Thomas Edison, Orville Wright, Marie and Pierre tions. He was the perfect fit.”

4 The Ultimate Team

ow does a team like this As a team and individually, survive 30 years? They say Phadke and Thorp have been Hthe strength of their collab- very productive. Phadke holds oration relies on their differ- five patents, has authored more ences. They describe Phadke as than 150 papers and has written an intuitive problem solver and or contributed to 22 books. Thorp as the theoretician with a Thorp holds two patents has background in control theory, authored more than 200 papers. probability and mathematics. They are both members of the “Arun knows everything National Academy of Engineer- about the power system,” Thorp ing and Fellows of the IEEE and says. “He always has an elegant, have been honored with many direct answer, and I tend to make honors and awards. As a team and individually, Thorp (left) and them more complicated. He has Thorp retired from Cornell a Richard Feynman-like intu- Phadke (right) have been very productive. and came to Virginia Tech in ition about things. He’s able to 2004, and the two continue their bring groups together and makes things happen,” he adds. association in closer contact. They have projects and contracts that Phadke says, “Jim is very competent in finding out the math extend several years into the future. that underlies the issue at hand. Not only does he recognize it, but “There are many more problems to solve,” Thorp says, noting he solves it. It’s remarkable to watch him doing things and realize that much of the equipment is more than 40 years old. “As a society, that, before my eyes, he’s doing something that has probably never we’ve got to modernize the power system and these measurements been done before.” are part of the story.” Protection Technology or eight years, Thorp com- lems in protecting the power it. ‘Who would want it?’ we Hundreds have been installed in muted one day a week from flow along the grid has been get- were asked?” this country and maybe a thou- FIthaca to New York, work- ting information from each of Soon after, Phadke came to sand in China, Mexico, Brazil, ing on different projects. At that the 3,000 power companies in- Virginia Tech and with his stu- and Europe.” time, power relays — that shut volved. “The power companies dents — including Virgilio Cen- Once a critical mass was in- down local power systems to could tell the voltage and the lo- teno, who is now on the ECE stalled, they started observing protect the equipment — were cation of a disturbance, but there faculty — built the first device, new phenomena along the pow- made of electromechanical and was no commonality when we which they called a synchron- er grid, Thorp says. “We learned solid state components. Thorp tried to study large blackouts, ized phasor measurement unit that disturbances spread through and Phadke developed the algo- like along the East Coast in 1965 (PMU). “Our goal was to make the system like waves. Here we rithms needed to replace the and 2003, and 1996 on the West very accurate measurements on had a man-made system behav- bulky machines with micro- Coast,” Phadke explains. the power system, no matter ing like earthquakes and tidal processors. The common measure was how big the network,” Phadke waves!” “Many people in the indus- time. When the GPS system was says. The device measures volt- The big disturbances can try said that computers couldn’t being established, Phadke real- ages and currents and identifies have an early warning system do such a heavy, dangerous job ized it could be used to time a precise time and location based along the grid. “They come at — that it couldn’t happen,” says stamp all the data in different on GPS signals. hundreds of miles a second. Thorp. “But, of course it has. power systems. “This was a huge The first units were in- That’s fast, but it’s not the speed Today you can’t buy anything idea,” says Thorp. They worked stalled at several power compa- of light. Computerized equip- but computer relays.” All of on the concept along with Stan nies around the country and by ment can react quickly enough. today’s power protection sys- Horowitz of AEP. “We devel- 1993, about two dozen firms This makes it possible to protect tems use Phadke and Thorp’s al- oped the algorithms and proved manufactured the instruments. the system differently,” Thorp gorithms in some way. it could be done theoretically, “The next step was computeriz- says. One of the biggest prob- but AEP did not want to pursue ing them in a large network.

5 SECURING THE AIRWAVES SO YOU DON’T HAVE TO Seeking a Secure Cognitive Network

he looming spectrum shortage created by the boom in wireless applications is gain- Ting attention nationwide. General news media covered the recent Federal Communications Commission (FCC) auction. has submitted a proposal to allow wireless broadband in the TV white spaces — those unused areas in the spectrum. Meanwhile, engineers are racing to perfect cog- nitive radio technology that is expected to play a large role in more efficient spectrum sharing. ECE’s Jung-Min Park supports efforts to deal with the overcrowded unlicensed bands, but he wants to avoid security problems that plague other networks, such as the . The best way to ensure security, he says, is to design for it from the very beginning. Park has received a $430,000 National Sci- ence Foundation (NSF) CAREER Award to head the first major effort to explore non-con- ventional security issues in cognitive, spectrum- sharing networks. The five-year CAREER

6 Jung-Min Park has an NSF CAREER award for cognitive network security

grants are NSF’s most prestigious awards for jun- “We expect that cognitive radio technology ior faculty. will be used for two-way communications in a “The spectrum shortage is hampering the de- wide range of applications, such as communication velopment and deployment of new wireless appli- systems for tactical military forces and emergency cations and technologies,” Park explains. “But, responders.” most of the spectrum has been already allocated The other major arena for the technology is for licensed use, and the FCC cannot allocate more the development of wireless access networks that bands for these emerging applications using the can provide Internet services to rural areas, he current regulatory paradigms. So, the FCC is considering open- ing up licensed bands — such as “It’s like living in somebody’s the TV bands — to unlicensed, secondary operations on a non- house at the same time as the interference basis with the li- censed users, who are typically owner — without ever providing called incumbents. In such a scenario, the sec- any clue that you are there.” ondary operators would carry the burden of using the bands when available and ensuring they do not interfere notes. The world’s first standard (IEEE 802.22) for with the licensed incumbents. The incumbents wireless access networks based on cognitive radio would not have to alter their operation or technol- technology is currently being developed for rural ogy. “This is a hard problem,” Park says. “It’s like wireless access. living in somebody’s house at the same time as the The advantages of this technology, however owner – without ever providing any clue that you can be offset by new security threats that have not are there.” been considered previously. “In a civilian cogni- One of the more promising technologies for tive , the motive of a malicious user these secondary operators is cognitive radios, might be to simply cause mayhem to other users which can sense and understand their environment to receive notoriety. This would be the equivalent and actively change their mode of operation, in- of computer hackers,” he adds. cluding frequency, modulation, and transmission Malicious users also could try to extort power. Researchers — including teams at Virginia money from providers who operate cognitive Tech — have developed working prototypes of radio networks and services. In a military setting, cognitive radios and now are working on high per- an adversary could try to bring down a network formance networks or interfere with its communications to gain a tac-

7 tical advantage. The third major problem involves overlapping cognitive radio “If you think of security after everything is finished, it’s too networks trying to operate in the same spectrum. He explains that late,” Park says. “First developing a functioning network, then guar- this problem can only happen with multiple secondary user net- anteeing security doesn’t work. The Internet is the perfect example, works. Because cognitive radios are flexible and can easily switch with its problems of spam, denial-of-service attacks, viruses, and bands – or even support each other’s traffic in a friendly manner — Trojan horses. Let’s break that paradigm. This time, let’s think about there will be interference issues. “How will the radios change their security at the design stage.” modulation, power, and frequency in those situations?” The prob- Security is possible to implement from the beginning, accord- lem is called network self-coexistence. “It turns out that there are ing to Park. “These are policy-based radios. They all follow human inherent weaknesses in the current 802.22 protocols for self coexis- rules written in software. They are not self intelligent.” tence. This is something that must be addressed before networks can Park and his students are fo- Jung-Min Park (right), Shucai Xiao (left), and Kaigui Bian want to secure cognitive cusing on non-conventional networks at the design stage. threats. He defines conventional security threats as those elements that threaten the confidentiality, authentication, or integrity of the data within the network. “Conventional security threats can be countered using off-the- shelf cryptographic solutions, such as encryption and authenti- cation schemes,” he explains. “We use the term ‘non-conven- tional security threats’ to denote threats that cannot be thwarted with cryptosystems alone.” The team has identified three different security problems “If you think of security after everything is finished, it's too late.” to explore and develop countermeasures against: incumbent emula- safely operate in this mode,” he says. tion; Byzantine failures in cooperative spectrum sensing; and vul- Probing a network before it exists introduces unique hurdles. nerabilities in cognitive radio network self-coexistence. Park foresees a big challenge in quantifying the security threats. Incumbent emulation would involve modifying the radio’s soft- “Finding and discussing these threats qualitatively is easier,” he says, ware to change its emission characteristics to appear to other users as “but we need to define exactly how severe each threat is. We want an incumbent. This possibility stems from the inherent programma- to identify those issues that have the most practical significance so bility of cognitive radios and would undermine the spectrum uti- that we can prioritize them. For that, we need to be able to quantify lization rules, ultimately reducing a network’s throughput. the threats. We will also want to quantify the effectiveness of our Byzantine failures would appear when incorrect sensing data is countermeasures.” sent to the network from rogue terminals run by adversaries or He anticipates that the most exciting aspect of the project will faulty radios with malfunctioning software or hardware. “This prob- be evaluating the countermeasures and solutions. “We would like to lem involves determining how a network can make accurate estima- do some partial implementation of our solutions. This is a novel tions or predictions in spite of bad information. Can you come up problem that nobody has looked into yet.” Finding the solutions with a scheme that maximizes the network’s ability to make accurate now, he says, will make cognitive radio networks more robust and predictions, even in a hostile environment where some of the nodes more reliable from the start. have turned bad?” Park queries. For more information, visit www.arias.ece.vt.edu. —with Liz Crumbley 8 rmed only with laptops, intrepid student explorers hunted this past November in what was possibly the world’s most uncoop- Aerative ad hoc network — and still managed to bag an elusive, quarry: a six-hop route. Undergraduate and graduate student teams gathered from seven universities to generate a first-of-its-kind mobile ad hoc network (MANET) and to compete for glory in its uncharted territory. The Mobile Ad Hoc Networking Interoperability And Cooperation (MANIAC) Challenge was organized by ECE’s Luiz DaSilva and Allen MacKenzie and held in conjunction with the IEEE Globecom 2007 in Washington, D.C. It was the first of at least two such com- petitions, funded with a three-year grant from the National Science Foundation (NSF). Teams competed from Auburn University, Bucknell Univer- sity, The George Washington University (GW), the Technical Uni- HUNTING IN versity of Kosice in the Slovak Republic, the University of North Carolina at Charlotte (UNCC), the University of Puerto Rico at Mayaguez, and Virginia Tech. THE WILD Seeking a natural habitat The goal of the competition was to generate interest in the field among students, while also providing one-of-a-kind opportunities to study actual, uncontrolled, ad hoc networks where users make their own decisions regarding tradeoffs between self-interest and common network goals. MANET Although the technology is imminent, MANETs do not cur- Photos by Christina O’Connor 9 A key goal of the MANIAC Challenge is to spur interest in the field among graduate and undergraduate students. rently exist outside of tightly controlled laboratory environment Each team controlled two laptop nodes on the network. and military deployments, according to MacKenzie. “Questions MANETs are based on the premise of users sporting different hard- linger about how well MANETs will work in the wild. Are simula- ware and software, so the only requirements were that the laptops tion results reported in the literature too optimistic about perform- have 802.11 capabilities and run the MANIAC API and OLSR as ance that can be achieved in these networks?” he said. the routing protocol. The MANIAC Challenge was the first large, multi-hop Strategy played a large role in the competition and teams were MANET that was spontaneously formed in a natural habitat, ac- evaluated on the creativity of the strategy employed. As a group, cording to DaSilva. “We have a need in this field for data from an ad the participants wanted to create a robust MANET and hoped to hoc network that is not controlled by any single research group. We spot elaborate, multi-hop routes. However, each individual team want to see what happens when we don’t control every , and wanted to acquire the highest number of intended packets. the different nodes may have different, and probably conflicting, in- To encourage both cooperative and selfish behavior, MANIAC terests,” he said. teams were awarded 10 points for every packet they received that was intended for them, but every packet they forwarded for another Strategic selfishness team cost them a point. Source nodes for each team were not part of The November competition focused on cooperation in routing the cooperative network, but issued packets and sniffed the network and packet forwarding.Cooperation is one of the biggest issues sur- to capture its topology. rounding MANETs, DaSilva said. For a stable MANET to exist, all The strategies were predominantly selfish and ranged from ex- nodes must cooperate, but still retain some selfish behavior in order tremely simple to very sophisticated. Most teams tried to drop pack- to achieve their own goals. “Will users of wireless ad hoc networks ets that would give other teams points, but maintain their reputation trade off , signal strength, or speed to ensure system ef- so that other nodes would still send them packets. fectiveness? If so, how? What incentives will get users to provide Other strategies included physically positioning their nodes services — such as forwarding and routing — to other nodes?” close to sources, limiting the proportion of packets sent to any sin-

10 “We were evil. We dropped every packet with a final destination for the next node.” gle node, and being unfriendly to nodes not in their direct path from the sources. “This was probably the unfriendliest ad hoc network in the world,” commented DaSilva at the conclusion of the contest. “We were evil,” admitted a member of the Auburn team. “We dropped every packet with a final destination for the next node. Dropping next-node packets was a popular strategy with the other teams as well.

“Live and let live” wins for creativity The team from Kosice won first place in creativity for their “live and let live” strategy. “Their strategy was ingenious,” com- mented MacKenzie. The Kosice strategy included manipulating the routing protocol itself to prevent traffic for other teams from being directed towards the Kosice devices at all. “We were hoping to see the teams come up with fairly simple Allen MacKenzie (left) and the MANIAC Challenge organ- strategies that when you put it all together would lead to reasonably izing team were looking to encourage student interest efficient outcomes for the whole,” MacKenzie said. “They didn’t do while creating and studying a live MANET testbed. the things we expected, but that is part of the fun of it.” “Everybody decided to be a bad guy,” DaSilva said. “This con- I expected. This doesn’t mean they are robust networks, however.” firms the prisoner’s dilemma.” The prisoner’s dilemma is a classical The UNCC team was almost always the multipoint routing game theory situation in which two players who may cooperate for node and took first place in the performance runs. The Bucknell gain or betray the other to go free typically choose to betray each team — the only team of undergraduates — came in second. other, even though this result is inefficient for both parties. “The most fun was to see people actually enjoying participating in an experiment of this type,” said DaSilva. “Getting students and But did it work? faculty excited about something like this is an intangible, but it’s very During the competition runs, teams roamed throughout the important in moving the research forward.” lower two floors of the Washington Hilton, while the non-network He cited evidence of growing enthusiasm among the partici- source nodes remained stationary. Many teams roamed, attempting pants. “We had undergraduates here, and their advisor reports there to be near certain sources or just for better network placement. is now a higher probability they will continue in the field and per- The network had the common stresses of any , haps get a higher degree.” Also, the Kosice team has written a con- with interference and non-users trying to gain access. In spite of the ference paper on their strategy and participation. hostility of the nodes, a complex topology appeared, with the great- DaSilva and MacKenzie are preparing for MANIAC Challenge est hops measured at 6 — extremely rare. II, which will focus on power control and spectrum usage. “I’m surprised it worked,” DaSilva said. “So many things can go Data from both events will be available to researchers at wrong — these networks are pretty fragile. This was less fragile than www.maniacchallenge.org.

11 SHRINKING LAB EQUIPMENT ONTO A CHIP GC Matrix System tackles faster analysis and lower cost with micro design.

asoud Agah has developed a microchip etch- ing process and a multi-column architecture Mthat he hopes to use to push gas chromatog- raphy (GC) out of its traditional laboratory setting and into the field. He wants to shrink GC units from their present table-top size to a credit-card size so they can be carried easily for instant analysis of hundreds of elements. Gas chromatography is the primary tech- nique used in scientific, medical and industrial laboratories for separating and analyzing volatile compounds. Portable microGC units would have many uses, ranging from doctors using breath analysis for diagnosing disease, to environmental monitoring of air and water contaminants to testing for chemical warfare agents. Gas chromatography separates chemicals from a compound sample that has been gasified. Using an inert carrier gas, the sample is propelled through a column that has coated interior walls. Molecules from the sample can be absorbed by the coating, which affects the rate at which differ- ent chemicals exit the column. Since different types of molecules exit the column at different times, thermal conductivity detectors at

12 Masoud Agah has received an NSF CAREER Award to develop micro gas chromatographs

the end of the column can identify the chemicals in the sample. In practice, The single-pass, several runs are used to confirm results and the time spent in the column can sometimes run more than an hour. multi-depth etching “It can often take four days to send a sample to the lab and get firm re- sults using gas chromatography or mass spectrometry,” Agah says. “There are many applications that can’t wait that long. So the separation and detec- process developed tion times become critical.” A number of research teams worldwide are working to develop fast, ac- by Masoud Agah’s curate microGC units, but Agah’s concept focuses on low-cost production methods and a novel, multi-column architecture. His etching process may research team may also help change how students in many fields study microsystems. His team’s preliminary results are encouraging and the National Science change how Foundation (NSF) has awarded him a $400,000 CAREER Award to support the effort. CAREER grants are NSF’s most prestigious awards for junior fac- university students ulty members who are considered likely to become academic leaders. Agah’s plan involves at least two critical advances — employing an array of microtubes instead of the single tube that is conventionally used in gas in many fields chromatography and developing a single-pass etching process for multiple study MEMS. channel depths. Matrix approach Most microGC systems use a similar structure to the large, table-top systems, employing a single, long column. While tabletop systems use columns about 10 meters long, Agah describes the current trend in microGC systems is to use 3-meter-long columns. “These systems cannot separate more than 20-30 compounds and have separation times measured in several min-

13 utes,” he explains. Faster analysis has been First-ever integration achieved by reducing the column length to less A GC Matrix system would integrate all the than 50cm and using rapid temperature program- sensors on a column for the first time. “We’re talk- ming. “These systems have separated multi-com- ing about a very compact microchip with inte- ponent mixtures in a few seconds. But there is a grated pressure, flow, thermal conductivity, and tradeoff between speed and resolution. They can temperature sensors, with columns and heaters.” only separate fewer than 10 compounds. They can “For easy commercialization, we want to de- go fast and few, but not complex,” he adds. velop technology that is simple, reliable, low-cost Agah’s goal is to separate complex mixtures – and robust,” he explains. “With this kind of com- Agah’s goal is more than 100 compounds — in a few seconds. He pactness, it’s important to minimize the fabrication to separate is tackling the speed/resolution tradeoff by using complexity. As you increase production steps, more than 100 a novel architecture he calls GC Matrix. The GC your yield goes down, because every additional compounds — Matrix will consist of short microGC columns less step introduces more opportunity for problems, than 30 centimeters long, with on-chip heaters, such as contamination.” in seconds. He temperature sensors, micro flow meters, and ther- is tackling the Instead of the typical silicon glass, Agah’s mal conductivity detectors. The columns will be team is using a silicon base employing a new fab- speed/resolution integrated into a matrix configuration, with each rication technology they call the CMOS-Compat- tradeoff by row responsible for certain boiling points. Within ible Predictable 3D Buried-Channel Process. “For using a novel each row, different columns will have different po- our integrated columns to work, we will need to architecture he larities and even different coatings. etch to four or five different depths from 10 to 120 calls GC Matrix. “At the end of each row, we’ll be spitting out microns.” He explains that the team wants to fab- results,” he describes. “That’s how we can get ricate the system using a single pass for etching and speed. We have independent rows, but also get the a single pass for deposition with no bonding. needed complexity because we’ll have different The team has eliminated a bonding process polarities in each row.” The performance of each for both power consumption and production rea- mGC column will still depend on a tradeoff be- sons. “If we use bonding, we will increase the total tween speed and resolution, he says, “but the GC mass of the chip,” Agah says. “When we increase Matrix will enable us to the mass of a chip, it needs more power to heat it Conventional gas chromatography tune these attributes in- up. By getting rid of bonding and its thick pyrex Sample Injector dependently on a sys- substrate, we reduce mass. Then our columns can Flow Controller tem level.” Agah be floating structures connected with thin dielec- already has developed tric layers. We can heat it up rapidly, because it is Waste columns that can sepa- Column isolated and the power consumption goes down. rate a limited number of Detector We cannot do this with silicon glass. We’ll be able volatile compounds in to keep the processing temperature during fabri- less than 10 seconds. cation less than 300°C, which makes it compati- Carrier Gas Column Oven ble with conventional IC manufacturing.”

Gas chromatography using GC Matrix Temperature Sensor On-Chip Detectors Separation Column Heated Column Heater Window 2 (TCD)

Sample Injection Fluidic Port

Downstream Sensor

Flow Upstream Sensor Carrier Gas MEMS Columns Heated Window 1 (Flow Meter)

14 “The beauty of research is we don’t know what will happen until we do it.”

Single-pass etching process ent polymers that separate different components. The team has recently tested a new method Since all of these sensors are integrated, will the of etching silicon to different depths in one pass coating affect the performance? Will there be any by maximizing a reactive ion etching (RIE) lag. deficiency in sensitivity and detectability?” he “We have concluded that with a structure that has wonders. wider openings, the etch is deeper. Based on the “The beauty of research,” he says, “is that we holes in the array and the dimensions of the holes don’t know what will happen until we do it. What and spacing between them, we can control the makes it fun is that we see so many challenges in depth and width of these channels.” front of us, and we know there will be more as we Since the technology allows different depths move forward.” and widths, even a single channel can have vary- For more information: www.ece.vt.edu/mems. ing dimensions, according to Agah. “We can even make nozzles with this,” he says. “This is just not achievable in pyrex.” Etching process may impact The single-pass etching tech- nique is not only useful for Agah’s engineering education microGC system, but holds promise he single-pass, multi-depth etching process developed by Masoud Agah’s research team for other microfluidic uses in life may change how students in many fields study microelectromechanical systems (MEMS). sciences and chemical analysis and in TAs microsystems become more common, students in many disciplines, including ECE, engineering education (see sidebar). mechanical engineering, engineering science and mechanics, chemical engineering, and bio- Although he has demonstrated sciences are being introduced to the technology. As part of Agah’s CAREER project, he will the new, single-pass, multi-depth be incorporating the process in a laboratory course for students from these disciplines. etching process and modeled the The new etching process is expected to make fabrication inexpensive and speedy enough GC Matrix, there are many chal- for classroom use in real applications. “We’ll be able to give students a deep, hands-on educa- lenges facing Agah’s team. Several tion in microsystems from design to fabrication to applications. Equally important, we’ll be hurdles include tuning Virginia able to have them work in truly interdisciplinary teams while in school,” he says. Tech’s existing equipment to ac- “With this etching technology, we can make many different systems, such as pressure sen- commodate the required sensitivity sors, micro mixers, particle (cell) separators, gas analyzers and more,” he adds. In the course, or even acquiring new deposition each multidisciplinary team will design a device based on the technology. “They can design capability. whatever they are interested in. It can be a sensor. It can be a microfluidic device.” Other hurdles are technical. Once they determine the overall design and the depth and width of their channels, they Once the etching technology is per- will have access to the software Agah’s team is developing for the gas chromatography project fected, the team will develop the to determine the layout. “We’ll be able to put all the designs onto one photo mask and have microcolumn with all the microsen- them all fabricated simultaneously using the single-pass process. Everybody will get trained on sors on it. “To do that,” Agah says, the different tools and fabrication processes and will contribute to the fabrication of class mi- “we first must fabricate the individ- crochips.” ual components to make sure we can With the chips fabricated, the teams will be able to analyze and test their systems, and de- get the sensitivity we need for each termine what design changes would be needed. component, then integrate it on a Teams of up to three students will work together for the design, with each student tak- chip. That seems routine, but a least ing the responsibility of his or her own discipline. The students will learn to communicate one part might become troublesome about their discipline at the level of students from other fields. “MEMS is by nature interdis- — coating the columns. We can use ciplinary,” he says. “Learning to communicate to professionals outside their field and learning typical coating techniques or use to work on a multidisciplinary team will make our students more valuable to employ- nanotechnology. ers.” is helping develop the course. “Getting the perspective from an IC “Then, we’ll need to make the company is very valuable,” Agah says. “Micron will help ensure that our students learn skills 30 cm columns coated with differ- that are state-of-the-art.”

15

SPACE WEATHER SPACE WEATHER The interaction between the solar wind and Earth’s magnetic field and upper atmos- phere can negatively impact the technology we rely on today — and engineers and scientists at Virginia Tech want to do something about it.

pace weather creates the beautiful auroras and striking night- professor of aerospace and ocean engineering (AOE), to an active shining clouds, but it can also interfere with communications group of eight faculty members with international reputations and Sand GPS systems or generate electromagnetic impulses that dis- two dozen graduate students and postdoctoral fellows. The center rupt the power grid. It is possible that space weather may also con- has more than $5 million in funding from the National Science tribute to the destruction of the earth’s protective ozone layer and Foundation (NSF), NASA, and various Department of Defense have a relationship to global climate change. (DoD) agencies. Space@VT has an enthusiastic Industrial Advisory Last year, Virginia Tech formed the Center for Space Science Board chaired by Dan Sable (’85, Ph.D. ’91) that has greatly con- and Engineering Research, directed by ECE Professor Wayne Scales, tributed to its rapid growth. for further understanding of fundamental space science, to help de- Three tenure-track and two research faculty members have velop technologies to mitigate the impact of space weather, and to joined ECE since 2006. That year, Robert Clauer came from the educate and train students in the field. University of Michigan and is stationed at the National Institute of The group, referred to as Space@VT, is studying the upper at- Aerospace (NIA) at Hampton, Va.; Scott Bailey came from the Uni- mosphere and beyond with ground-based and space-based equip- versity of Alaska, Fairbanks; and Brent Ledvina came from a post- ment as well as with computer simulations using advanced doctoral position at the University of Texas at Austin. computational physics methods. This past year alone, graduate stu- The new research professors include Daniel Weimer, from dent Lyndell Hockersmith traveled to Antarctica for the installation Solana Scientific, Inc., and Ray Greenwald, who is retired from of a magnetometer near the South Pole; the HokieDARN radar JHU/APL. Weimer, stationed at NIA at Hampton, is the developer array joined an international system observing the ionospheric elec- of the model that has become the international standard of global tric field; an ECE professor served as deputy principal inves- electric fields and potentials. Greenwald is the chief architect of the tigator for NASA’s AIM mission; and Virginia Tech international SuperDARN radar concept. students became the first U.S. university students A major focus of the space science team is educating and train- to study Global Navigation Satellite Systems ing undergraduate and graduate students in the field, according to (GNSS) with the first in-house Galileo Scales. “We are pursuing a holistic approach to space research and “We (European GPS) simulator at a U.S. space mission development by combining theory, modeling, obser- university. vation, data analysis, and education,” he says. “Our goal is to pre- want to In two years, the cen- pare students to become leaders in the field and to make important ter grew from a pro- contributions to society as a whole.” understand posal by Scales The center encourages undergraduate students to get involved the physical and Joseph J. in its projects. Undergraduates can make a serious contribution Wang, an through both building and analysis activities, according to Bailey. processes of the associ- “The educational benefits are great,” he says, “but the truth is, it’s ate just plain fun.” interactions, but The team has also been developing courses in space and atmos- we’re an engineer- pheric science to introduce students to the field. “One of the beau- tiful things about this field is you have to be just as competent at ing department; science as engineering,” says Scales. “We want to understand we want to know the physical processes of the interactions, but we’re an en- gineering department; we want to know how it affects how it affects technology. We don’t want to be doing science for science’s sake. It’s a means to an end to understand technology.” how it affects our technology.” For more information, visit: www.space.vt.edu.

17 TOM ELKLUND

cott Bailey is interested in the interactions of a lot of theories. Once we understand how they space weather with the Earth’s atmosphere. form, we will be able to go back and determine if SWhy did noctilucent (night shining) clouds they have anything to do with global warming or appear at about the same time as industrialization? human activity. Do the auroras play a part in ozone destruction? To get the data to study such questions, he has Do auroras take part been active in building satellites, spacecraft, and in destroying the ozone layer? equipment. Bailey is also involved with studying if and how the auroras impact Earth’s protective ozone Why do noctilucent clouds form? layer. “There is a large and growing body of evi- Bailey currently serves as deputy principal in- dence showing that solar energetic particles from vestigator of NASA’s Aeronomy of Ice in the the aurora lead to production of nitric oxide Mesosphere (AIM) mission, working with James (NO),” he describes. “We know that there is an Russell (BSEE ’62), a professor at Hampton abundance of nitric oxide in the thermosphere (in University. The AIM satellite is the first mis- the region of the auroras). When we get to polar sion ever to study noctilucent clouds, which winter, the night is so long, the nitric oxide may are called Polar Mesospheric Clouds flow downwards. Then, when it comes down, it’s (PMCs) when viewed from space. The a catalytic destroyer of ozone. It’s not responsible clouds, when viewed from the ground, for the ozone hole, but may have a part in the de- are seen as very bright clouds reflecting struction of ozone. the sun at twilight. These particles may form a coupling between “These clouds form about 50 miles the highest and lowest part of the atmosphere, ac- high – at the edge of space,” Bailey ex- cording to Bailey. “The problem is, we can’t meas- plains. “The density of water molecules is ure nitric oxide at night. It’s never been done.” one in a million. This is less than the Sa- Bailey and Chris Hall, an aerospace professor, are hara desert, yet the clouds form – always in working with researchers at the University of Col- summer and always in the polar region. orado. The team has developed a method to look What makes these clouds interesting is not at how the atmosphere attenuates at night, and just their striking beauty, but they did not using that to calculate NO levels. appear until about 120 years ago. “Because They are preparing a 5-minute sounding their rise coincides with industrialization, rocket flight in January 2010 from Poker Flat, there is a suggestion of a link.” Alaska. A large telescope payload (being built by Over time, the clouds have become brighter, Virginia Tech faculty and students) bolted to the have been seen more often, and appear to be oc- rocket will focus on a bright UV star in occulta- curring at lower latitudes. “We’ve never studied tion – as it is being covered by Earth’s atmosphere. these clouds except as serendipitous satellite and After the sounding rocket, the team hopes to ground observation. How do they form with so expand the effort to include measurements on the little water vapor? How does this work? We have same star, but from a satellite. AERONOMY OF ICE 18 SPACE WEATHER

EXPLORING SPACE Bob Clauer’s data analysis work has taken his team to FROM ANTARCTICA the very edges of the planet.

ob Clauer wants to understand how Earth’s helped to establish an ionospheric HF radar at Vir- electromagnetic fields respond to solar activ- ginia Tech, and also is principal investigator on a Bity. He explores the solar wind/magneto- project to develop an array of magnetometer plat- sphere interaction from the ground. forms in the southern hemisphere. The first plat- He describes the space environment as an form was installed in Antarctica in January. The electrodynamic system that involves plasma goal is to install a chain of seven to eight stations physics. “The solar wind interacts with Earth’s over the next three to four years magnetic field in a manner similar to a fluid, but an The chain is being installed along the 40° electrically conducting fluid.” magnetic meridian — magnetically conjugate (rec- A consequence of this interaction is that elec- iprocal) to a chain of magnetometers on the west tric currents are generated and flow to the iono- coast of Greenland. The chain reacts rapidly to sphere. “It’s a large, coupled system.” Variations in changes in the solar wind. With the Greenland the magnetic field and the energization of electri- chain, researchers have been able to identify dif- cally charged particles are the items that comprise ferences in the electrical coupling between the space weather. solar wind, magnetosphere and ionosphere during The energy that is coupled to the magnetos- the summer and winter. phere from the solar wind and dissipated through “We don’t believe that it’s changing due to electric currents in the upper atmosphere and the time of year,” Clauer says. “We think it’s probably precipitation of energetic particles into the upper the difference in conductivity in the hemisphere.” atmosphere (producing the aurora) — adds up to The research has been hampered by only having about 1012 W. “That’s the same energy as a typi- data from one pole. With the Antarctic chain, they will be able to study polar winter “It seems that if you drive and polar summer simultaneously. The array will also be used to help the magnetosphere strongly, understand a phenomenon first ob- served during magnetic storms only it goes into a periodic oscil- about 10 years ago. “It seems that if you drive the magnetosphere lation. Why does it do that?” strongly, it goes into a periodic os- cal hurricane, but spread over a much larger area.” cillation. Why does it do that?” Scientists and engineers study the space envi- Even with a single station at the South Pole, ronment using magnetometers to look at electric the team is getting data that helps the investiga- currents, radar to measure the drift of plasma and tions, Clauer says. “I’m a data analyst. The art is in infer the electric fields. Particle detectors, various assembling data in ways that allow you to see radio remote sensing instruments and optical in- things. I manipulate data to reveal different kinds Graduate student struments are also used. of behaviors. We can’t control things in this lab, so Lyndell Hockersmith Clauer investigates the global type phenom- we do it by trying to control the various variables near McMurdo, Antarctica ena using global arrays of instruments. He has through a statistical analysis.”

19 The effects of space weather on SATELLITE NAVIGATION rent Ledvina studies the effect of space ied is solar radio bursts. “These can cause noise in weather phenomena on satellite navigation the GPS transmission band, making the signal-to- Bsystems. “The primary science,” he says, “is noise ratio go down, thus making a GPS signal dif- looking at propagation issues and how ficult to track. It’s like the noise on your TV set the chaotic ionosphere (the ionized part of the when your cable is out and somebody turns on the Earth’s upper atmosphere) can disturb radio waves microwave or blender,” Ledvina explains. via refraction, reflection, diffraction, and absorp- A solar radio burst in the fall of 2006 was an tion.” order of magnitude larger in strength than ever pre- His work recently focused on the mid-lati- dicted. “It knocked out a large percentage of the tudes between 22° and 60° latitude. “Previously, science-grade GPS receivers on the daylight side of that part of the ionosphere was considered ab- the U.S. for several minutes. We assumed we un- solutely boring. Nothing was happening there. Or derstood the worst case and it turned out we had no so we thought,” he says. Historically, the interesting clue,” he says. phenomena occurred at the equator and near the To study these effects, Ledvina builds instru- AAIMAGE NASA poles, he explained. Then, public data from sur- mentation to collect and analyze the data. GPS is veyed GPS receivers started to reveal some eccen- used to measure the line-of-sight integrated plasma tricities of the ionosphere in the mid-latitudes. density from a receiver on the ground to a GPS “We didn’t see it until we had the GPS data satellite. Using arrays of receivers, he is involved in from all over the U.S. It is not only interesting sci- mapping the ionospheric content. entifically, but potentially has an impact on society One project involves putting GPS receivers in and the technologies we rely on,” he says. Chile and Colombia to understand the conjugate One of the main eccentricities is the occur- effects of the Rayleigh-Taylor instability on the rence and dynamics of large plasma densities in the plasma densities of the equatorial ionosphere. A ionosphere, he explained. Plasma is the fourth state simple explanation of the Rayleigh-Taylor instabil- of matter – an ionized gas where the electrons in an ity is the situation in which a heavier fluid is on top atom or molecule separate from the nucleus. On a of a lighter fluid, an obviously unstable situation, grand scale this leaves a soup of positively charged which typically results in chaotic mixing of the two ions and negatively charge electrons in the fluids. By observing from two locations on opposite upper atmosphere. The large plasma densities sides of the Earth’s magnetic equator, the team will generate instabilities, which in turn can cause be able to study the instability’s effects as they prop- errors in the received signals from the GPS. agate down the geomagnetic field lines. “Above the Midwest, for example, there is Another project involves building a commer- The solar wind inter- essentially a very benign low-density ionosphere, cial-grade GPS receiver based on software-radio acting with Earth’s then during a space weather event, a wall of den- technology. “The GPS receivers we build will be magentic field and sity can form and flow through Canada towards able to work easily with the European, Russian, upper atmosphere the North Pole. We do not understand these Chinese and other satellite navigation systems. The can disrupt satellite plasma flow dynamics. They cause perturbations commercial market doesn’t produce receivers that navigation systems. to the position solution output by our GPS re- operate well during challenging space weather Brent Ledvina studies ceivers. The real problem is, the GPS receivers events,” he says. With more robust receivers, the these effects to weren’t designed to deal with such a large gradient team will be better able to measure the extremes of develop the tech- in electron density,” Ledvina says. space weather. nology to predict Why does position matter? The Federal Avia- Ledvina is also upgrading and developing and avoid these tion Administration (FAA) has a mandate to allow ECE’s GPS course and laboratory. Virginia Tech is disruptions. commercial planes to land using GPS. “Getting an the first U.S. university to have a simulator for incorrect position could be devastating.” Galileo — the European GPS system that will go Another interesting phenomenon being stud- online in the next 4-7 years.

20 SPACE WEATHER

Wayne Scales, director of the new Center for Space Science CREATING WAVES and Engineering Research eing an expert in computational space plasma physics has in- be effective? If we dump a certain amount of chemicals, how much volved Wayne Scales in projects from analyzing the effects of wave energy will be involved?” Bhigh-altitude nuclear detonations to creating and perturbing Another project in space computation involves noctilucent charged dust clouds in space. clouds that form at the edge of space, shine at dusk, and are believed In a multi-university effort funded by the Department of De- to be related to global climate change. Over the past several years, the fense, Scales and Joseph Wang, an aerospace professor, are develop- team has developed a comprehensive computation model for inves- ing a model to mitigate the impact of the earth’s radiation belts on tigating the interaction of high power radio waves on these charged space assets. “This is part of a multi-university effort to counteract clouds for diagnostic purposes. a high-altitude nuclear detonation (HAND). Such a detonation “We’ve gone as far as we can with the theory; now we want to won’t affect the people on earth, but the radioactive particles are pre- do experiments to validate our theory;” Scales says. The team is dicted to destroy the electronics on spacecraft and basically wipe out building a radar receiver to use in Alaska at the high frequency ac- most of the low-earth orbiting satellites in about a week,” he says. tive auroral research program (HAARP) facilities The project’s goal is to develop novel techniques of generating The team not only studies natural clouds, but is involved in a electromagnetic waves that interact with the radioactive particles and Naval Research Laboratory project to create an artificial noctilucent scatters them out of the radiation belt, he says. “One way to do that cloud. Called the charged aerosol release experiment (CARE), the is to use a big, high-power transmitter on the ground that sends a project entails sending a sounding rocket from Wallops Island, Va., high power radio wave. Another option would be to use a satellite to create a large dust cloud over the East Coast. that has a high-power transmitter, he says” The Virginia Tech team will be involved in developing a theo- The Virginia Tech team is involved in a third option: using a retical and computational model to study the turbulence generated spacecraft that ejects chemicals that photo-ionize and create electro- in the charged dust cloud. “Radars will be used to bounce signals off magnetic waves which then interact with the radioactive particles to the dust cloud to see if the turbulence, which is linked to global scatter them out of the radiation belts. Scales’ and Wang’s model ad- change, is the same as a natural noctilucent cloud,” Scales says. The dresses the effects within seven days of a high altitude detonation. sounding rocket project principal investigator is Paul Bernhardt of “We’re trying to determine what is the most efficient and quickest the Naval Research Laboratory. “We’re working to see if the new way to counteract this threat. How much chemical do we dump? Blackstone SuperDARN radar will be able to contribute to the proj- How much wave energy do we need to create for the scattering to ect as well.”

21 SOKPHOTO iSTOCK

IT’S RAINING PLASMA Those ionospheric plasma winds are blowing up a storm CE’s newest laboratory stretches thousands a dozen countries. High frequency radars are po- of kilometers into the ionosphere from a sitioned around the world and operated continu- Efield near Blackstone, Va.. The HokieDARN ously to provide the only method of obtaining radar enables first-time-ever, continual mapping global, instantaneous maps of plasma convection. of space weather plasma motions over the north- “The ionosphere is like a CRT; it projects a ern United States and southern Canada. picture of what is happening in Earth’s near-space HokieDARN is the newest part of the Super environment,” explains Michael Ruohoniemi, Dual Auroral Radar Network (SuperDARN) who is on the SuperDARN project. “We can see which is an international collaboration involving motions in the plasma in the ionosphere that re- SUPERDARN 22 SPACE WEATHER

The Blackstone SuperDARN field-of-view plot. semble winds. When we com- to study the magnetic storm bine the measurements from electric fields. The first mid-lati- all the radars, we generate tude system was built in 2005 at something that looks like a fa- Wallops Island, Va., by the Johns miliar weather map, only the Hopkins Applied Physics Labora- speeds reach thousands of miles tory (JHU/APL) and NASA God- per hour and change in a few sec- dard Space Flight Center (NASA/ onds. GSFC). Scientists around the world use Su- The targets for the radar system are perDARN data to help understand the many plasma irregularities in the ionosphere that often effects of space weather, according to Joseph Baker, cause problems with other systems, such as GPS, sur- who is also a SuperDARN team member. “The Earth’s mag- veillance radars, and HF communications. “It is a case of one netic field is like wires that transfer the energy from the solar wind guy’s noise becoming another guy’s signal,” describes Baker. With into the upper atmosphere,” he explains. “When the near-Earth the mid-latitude data, scientists were able to continuously monitor space environment (or magnetosphere) gets stressed, it corrects by both storm and quiet time activity over a larger area. “We quickly dumping energy into the atmosphere via the auroras and heating mapped the expansion of storm-time electric fields from the auro- from powerful electric currents.” ral zone to mid-latitudes with the Wallops radar and discovered a SuperDARN was first built in the 1990s as a chain of radars new type of irregularity that populates the ionosphere just equator- ringing the auroral latitudes and pointing towards the poles. “We ward of the auroral zone every night.” wanted to study the auroral processes that occur daily and their con- The HokieDARN radar is the second mid-latitude system built nection to the solar wind,” Ruohoniemi says. The SuperDARN ef- in the United States and the third in the world, after the Wallops forts succeeded in producing the first-ever direct two-dimensional radar and a Japanese radar operated on the island of Hokkaido. It images of convection on global spatial scales. The resulting discov- was turned on in February of this year, just in time to contribute eries touched on the complementary nature of convection in the ‘ground-truth’ to a major NASA satellite mission (THEMIS) that is northern and southern hemispheres, the occurrence of hurricane- studying the causes of the auroral substorm. The radar was built with like vortices in the plasma flow, and the rapid response of convection funding from the National to change in the solar wind Science Foundation (NSF) as The HokieDARN radar array Until recently the mapping was available only for the far north- a collaboration between Vir- ern and southern latitudes. This is sufficient for studying such phe- ginia Tech, JHU/APL and nomena as the magnetospheric substorm, which occurs frequently Leicester University in the and is mostly confined to auroral latitudes. Powerful magnetic United Kingdom. storms, however, which occur much less often but have more seri- HokieDARN was raised ous effects, trigger very large disturbances in the space environment by a team of scientists and and can even cause auroras to be seen as far south as Texas. engineers from the collabo- “These events are big and dramatic — and can be dangerous for rating institutions lead by the people flying over the poles in aircraft, for astronauts, for GPS and new arrivals to ECE, i.e., other communication and radar systems,” Ruohoniemi says. “The Ruohoniemi, Baker, and Ray impacts get even more significant at the mid-latitudes since more Greenwald, who has joined as people live there and the density of vulnerable technology is greater. a research professor. Green- The original SuperDARN radars were pointed towards the wald pioneered the use of HF poles and were missing the expansion of such large events. The Su- radar for ionospheric studies perDARN collaborators decided to begin installation of a chain of and is the primary founder of mid-latitude radars, which is sometimes referred to as StormDARN, SuperDARN.

23 The HokieSat is one of three in HANDS-ON SPACECRAFT hris Hall, a professor of aerospace and ocean particles. His students are currently building a NASA’s Ionos- engineering, is an expert in spacecraft dy- scramjet payload for a two-stage sounding rocket, pheric Observation Cnamics and control. He is involved in model- which will launch in 2010. ing and simulation of complex spacecraft systems His modeling and simulation of complex Nanosatellite and hands-on student projects. spacecraft systems ranges from high-altitude bal- Formation mis- A couple of recent projects started as student loon payloads to small satellites. In a recent study design projects, including HokieSat, one of three for NASA Goddard, his team completed a control sion. Above right: satellites that comprised the Ionospheric Observa- system analysis for a tethered satellite system. They A sounding rocket tion Nanosatellite Formation mission, funded by are currently modeling electrodynamic tether sys- the U.S. Air Force Office of Scientific Research tems with rigid end bodies that use internal and was collected after and NASA. external torques for attitude control. The current flight for its pay- A sounding rocket mission, which launched study is aimed at understanding the interactions of from Wallops Island in 2005, carried a Naval Re- the tether’s motions with the motions of the end load of particles search Laboratory payload to collect mesospheric bodies. from the mesosphere PROBLEMS WITH MOON DUST oseph Wang, an associate professor of aerospace observed by the Surveyor spacecraft and later by and ocean engineering, is an expert in advanced Apollo astronauts. Jplasma propulsion systems, spacecraft-environ- It is well documented that lunar dusts can mental interactions, and computational physics. cause a wide range of significant problems for both He describes his work as interdisciplinary, spacecraft and astronauts on extra-vehicular activ- concerning both spacecraft engineering and space ities. Currently no technology exists that can ef- science and combining theoretical studies, exper- fectively mitigate the effects of lunar dusts. imental studies, large-scale simulations, and mod- Utilizing computer particle simulations and vac- eling. Ongoing work in his group ranges from ion uum chamber experiments, Wang and his students thruster plume interactions with spacecraft and are trying to understand the dynamic processes spacecraft charging on lunar surface, to plasma that levitate and transport lunar dust grains and de- micro-instabilities relevant to radiation belt reme- velop a technology to actively control and miti- AAPHOTO NASA diation experiments. gate the dust environment surrounding lunar One ongoing study in Wang’s lab concerns spacecraft. charged dust interactions on lunar surface. Dust clouds suspended above the lunar surface were first

24 SPACE WEATHER New space science courses cover planetary physics and the perils of space weather ow does the sun’s atmosphere and magnetic field interact with gen. “My goal in the class, was to show students that with the math- the earth’s atmosphere and magnetic field? How does this inter- ematics and engineering and physics courses they had already taken, Haction impact modern electrical technologies? they could reason out these differences.” Why does Jupiter look so different from Earth? Why is Earth’s The course covers ion and neutral chemistry, ionization by solar atmosphere different from that of Mars and Venus? What electrical Extreme Ultraviolet (EUV) photons and charged particle radiation, engineering principles are used to observe such differences? heating and cooling processes, diffusion, neutral upper atmospheres, With the knowledge students have from sophomore and junior exospheres and ionospheres, and solar wind/ionosphere interactions. engineering and physics classes, they can work through and calculate “Weare trying to teach the students problem-solving and at the same the answers to these questions, according to ECE’s Scott Bailey and time get them fired up about space science and engineering,” Bailey Bob Clauer. Bailey and Clauer used these questions and solutions as says. Although it’s a graduate-level course, it is open to the best un- the framework for new courses taught last academic year. dergraduates. “We are trying to get undergraduates more confident Bailey’s course, “Introduction to Space Science II,” concentrates about their own ability and be able to jump in and try their hand in on the upper atmosphere and gives a quantitative treatment of ionos- this field,” he said. pheric physics and aeronomy (the science of the upper atmosphere), Two other new courses in the series, “Introduction to Space based on our solar system. “If you think about the physics and work Science I” and ‘The Perils of Space: An Introduction to Space through the questions, you can get a long way towards understand- Weather’, were developed by Bob Clauer. The introduction course ing why the planets have their characteristics. Weall started the same, covers the electrodynamics, plasma physics, and chemistry of the but have different locations relative to the sun,” he says. near-earth space environment from the sun to the earth’s upper at- Location from the sun determines a planet’s temperature, which mosphere. The space weather course is a 4000-level course empha- leads to different evolutions, he explains. The planets then develop sizing the practical consequences of space weather on modern different atmospheres; Mars developed a thin atmosphere, Venus de- electrical technologies, such as solid state devices, satellite technol- veloped a thick one, and Earth developed an atmosphere with oxy- ogy, communication, and global navigation systems.

Undergraduate reaches for the edge of space

n instrument designed and built to observe polar mesospheric ratio of the ozone and neutral Christina O’Connor clouds (night shining clouds) from space can also measure air scale heights.” Aozone, according to results verified by the research of under- Hunter, who started graduate Heather Hunter (ECE ’08). Hunter is working in the working in the laboratory last Aeronomy and Remote Sensing Laboratory, analyzing data from the May, says she was initially NASA AIM satellite that launched last April. surprised by the amount of She presented her results in a poster session at the American space science research and the Geophysical Union conference in San Francisco, Calif., in December complexity of the projects. “I was also very surprised that there were 2007. so many opportunities emerging in space science research for stu- The cloud imaging and particle size (CIPS) instrument is ob- dents. I’m glad to see the department encouraging students in this serving the clouds and determining particle sizes and the proportion area.” of the incident light that is reflected. “When the clouds are not pres- Before joining the laboratory, she had decided she most enjoyed ent,” she explains, “CIPS observes only the sunlit Rayleigh-scat- the area of electromagnetics. She had a strong interest, but no pre- tered background brightness, which is controlled by ozone present vious course work in space or atmospheric science and had much to above 40 km from the earth’s surface.” learn. Her experience has convinced her to follow a career in the She created a model of the atmosphere from existing data and field. She wants to work in RF propagation engineering, then re- compared it to the satellite data, following a technique developed turn to school for more education in atmospheric science. “This is an for solar backscattered ultraviolet instruments. “Our results show exciting area of study with a very promising future. This isn’t ‘main- that CIPS can reasonably measure ozone column density and the stream EE’, but I’m eager to see more students get involved.” 25 2007 BRADLEY 2008 FELLOWS Robert M. Gardner BSEE ’03, MSEE ’05, Ph.D. ’08, Virginia Tech 11 alumni Bradley Fellows Advisor: Yilu Liu Research: Wide area monitoring and control of serve as facultymembers large-scale, complex networks, such as power systems. He is working on frequency data at universities analysis and conditioning, power system event detection, and power system event location using the FNET wide area frequency monitoring across the country network developed at Tech.

Mark W. Baldwin William C. Headley BSEE ’93, MSEE ’05, Ph.D. ’08, Virginia Tech BSEE ’06, Virginia Tech Advisor: Yilu Liu Advisor: Claudio R.C.M. da Silva Research: Power system dynamic response to Research: Signal detection and modulation line and generator outages. Focus on the use classification and its applications to cognitive of bulk power system eigenproperties to deter- radio systems. He developed a distributed fea- mine event type; location and assess overall ture-based modulation classifier that showed power system condition. Also studying genera- how distributed system can out-perform non- tor rotor train torsional response to pulsating distributed classifiers. He is now developing a loads, transformer condition assessment, likelihood-based modulation classifier in multi- FACTS/ESSS applications in power system os- path fading channels. cillation damping. Daniel Friend Ryan Irwin BSEE, MSEE ’98, Brigham Young University BSCPE ’07, Mississippi State Advisor: Allen MacKenzie Advisor: Luiz DaSilva Research: Cognitive networks, which are the Research: Development of a MAC protocol for combining of intelligence with highly reconfig- a dynamic spectrum access (DSA) environ- urable communication networks. Specifically an ment, related to the Wireless Network after application for dynamic spectrum access and Next (WNaN) project. He is building on prelimi- another for routing in mobile wireless net- nary work on multi-channel MACs, while incor- works. porating the new DSA design challenges. Career plans: Joining Northrop Grumman TASC this fall as a communications systems engi- neer.

J. Shawn Addington (BSEE ’90. Advanced Design Group, Ray A. Bittner, Jr (Ph.D. ’97) MSEE ’92, Ph.D. ’96) Portland, Ore. Research Department Head, ECE August is working on process sensi- Sammamish, Wash. BRADLEY Virginia Military Institute tive mixed-signal circuits. Bittner has projects in computer ar- Lexington, Va. chitecture, run-time reconfigura- Addington has been awarded the Carrie Ellen Aust (BSCPE ’98) tions and portable devices. Jamison-Payne Institute Professor- ship in Electrical Engineering William Barnhart Kirsten Brown (BSEE ’94) ALUMNI (BSEE ’00, MSEE ’02) Chief of Staff to the CEO Sarah S. Airey (BSCPE ’01) Raytheon; Denver, Colo. MicroStrategy Inc., Recently graduated from Raytheon’s Alexandria, Va. JoAnn M. Adams (BSEE ’94) Christopher R. Anderson (BSEE Engineering Leadership Develop- Co-owner, Big Fish Design ’99, MSEE ’02, Ph.D ’06) ment Program and was awarded Steve Bucca (BSEE ’87, MSEE ’90) Centerville, Va. Assistant Professor, ECE Technical Honors by his peers. United States Naval Academy Mark Bucciero Robert J. Adams (MS’95,Ph.D.’98) Annapolis, Md. Brian L. Berg (Ph.D. ’01) (BSCPE ’01, MSCPE ’04) Assistant Professor, ECE Director of Engineering and Product Argon ST, Inc.; Fairfax, Va. University of Kentucky Matthew Anderson (BSCPE ’04) Development Lexington, Ky. DTS; Agoura Hills, Calif. R. Michael Buehrer (Ph.D. ’96) Won 2006 NSF CAREER Award Nathaniel August (BSCPE ’98. DTS is known for its audio codec Associate Professor MSEE ’01, Ph.D. ’05) that is now mandatory in next-gen Virginia Tech Design Engineer home theater systems. 26 Evan M. Lally David Reusch BSEE ’03, MSEE ’06, Virginia Tech BSEE ’04, MSEE ’06, Virginia Tech Advisor: Anbo Wang Advisor: Fred C. Lee Research: Development of a high-resolution Research: High frequency DC-DC conversion to particle imaging system. Also developing a miniaturize power supplies in such applications sapphire pressure sensor for ultra high-temp- as telecom, automotive electronics, laptops, erature harsh environments – operating up to servers, and wireless communications. Devel- 1500°C. Investigating a new method of sensor oping a three-level buck converter for low cur- construction through a novel combination of rent point of load applications. He is working etching and bonding techniques applied to on a fully integrated product based of this single-crystal sapphire components. topology.

Mark A. Lehne Rebecca Shelton BSEE ’94, Seattle Pacific University; MSME BSE EE/BA English ’06, University of Ten- ’98, MSEE ’00, Oregon State University. nessee at Chattanooga Advisor: Sanjay Raman Advisor: William Baumann Research: Analog and mixed signal IC design, Research: Modeling and parameter estimation specifically new discrete-time signal processing of small gene networks, especially networks circuits that will enable more power efficient, created by synthetic biology. She is currently in- interference immune UWB wireless trans- vestigating how much data is needed to ensure ceivers. His discrete-time FFT processor is that the parameters identified are biologically being used in wireless digital handheld devices meaningful. for higher data rates.

Andrew Love Ethan B. Swint BSCPE ’05, University of Virginia BSECE ’02, Baylor; MSME ’05, University of Advisor: Thomas Martin Texas, Austin Research: Modeling and pattern recognition Advisor: Krishnan Ramu with e-textile sensor systems. Accelerometer Research: Circuit topologies and control sys- and gyroscopic sensors are deployed on e-tex- tems for switched reluctance machines, which tile pants to determine the activity of the user are limiting factors in the technology’s adop- and location of sensors. High accuracy real- tion. He is working on novel circuit topologies time realization of this can allow for accurate to reduce the number and cost of electrical tracking of users. components, which, in turn, requires the devel- opment of new control strategies.

Parrish Ralston Phillip A. Zellner BSEE ’06, Virginia Tech BSEE ’07, Virginia Tech Advisor: Kathleen Meehan Advisor: Masoud Agah Research: The physical phenomena that char- Research: Development of a MEMs device tar- acterize isolated gate bipolar transistors geted at the separation of cancer cells from (IGBT). She is characterizing 5th generation low blood. He is using micromachining techniques punch-through carrier-store trench-bipolar-tran- to develop a low power, high yield separation sistors for the Freedom Car project and will device based on demonstrated mechanical and work at NIST this summer in parameter extrac- electrical property differences between cancer tion of Si IGBTs and other high-power SiC de- cells and healthy cells. vices.

Charles F. Bunting (Ph.D. ’94) Carson is also serving as a judge Daniel Davis (BSEE ’03) W. Ashley Eanes (BSEE ’95) Associate Professor at the Formula SAE competition in Duke Energy, Burlington, N.C. Oklahoma State University Danville, Va., in late April. Scott Davis (BSCPE ’00) Richard B. Ertel (Ph.D. ’00) Carey Buxton (Ph.D. ’02) Ricky T. Castles (BSCPE ’03) Brian M. Donlan (MSEE ’05) Electronics Engineer, FBI Ph.D. Student; Virginia Tech Brian F. Flanagan Buxton has been named a Direc- Joel A. Donohue (MSEE ’94) (BSEE ’97, MSEE ’98) tor of National Intelligence Fellow. Eric Caswell (Ph.D. ’02) Thomas Drayer (Ph.D. ’97) Kevin P. Flanagan Scott C. Cappiello (BSCPE ’94) Kevin Cooley (BSEE ’02) (BSCPE ’00, MSCPE ’01) Senior Director Industrial Automation Specialists Bradley D. Duncan (Ph.D. ’91) Rancho Cordova, Calif. of Program Management; (IAS) Corp., Hampton, Va. Professor, ECE MicroStrategy, Inc., Cooley enjoys opportunities in University of Dayton, Ohio Todd Fleming (BSEE ’94, MSEE ’96) Carlsbad, Calif. embedded systems and design He is responsible for product plan- and testing electrical circuits. Gregory D. Durgin (Ph.D. ’00) Ryan J. Fong (BSCPE’01,MSCPE’04) ning for some business intelli- Assistant Professor, gence products. Cas Dalton (BSCPE ’03) Georgia Tech; Jayda B. Freibert (BSEE ’98) Won 2006 NSF CAREER award J. Matthew Carson (BSEE ’98) Phillip Danner (BSCPE ’91) Won the Class of 1940 Howard Bradley H. Gale (BSEE ’97) Engineer, Engine Dept. Ector Classroom Teacher Award – Joe Gibbs Racing Bradley A. Davis (Ph.D. ’01) the highest teaching honor at Daniel J. Gillespie (BSCPE ’95) Huntersville, N.C. Georgia Tech. 27 “I can confidently say this is where I was meant to be, and immersion in a culture of students with diverse mindsets, professors 2007 BRADLEY with thorough knowledge, and an environ- ment of passion and compassion for others has changed me for the better.” 2008 SCHOLARS Daniel Michael Hager

Benjamin A. Beasley Brittany Clore EE/Music ’09 CPE ’10 Kernersville, N.C. Fairfax, Va. J.B. West Scholarship; National Merit Scholar; Gamma Beta Phi; Hypatia Engineering Com- Robert C. Byrd Scholar; Sam Walton Community munity. Scholar; BPO Elks Walter “Buddy” Green Career aspirations: working with robotics and Scholar; Guilford County Schools/Harris Teeter encouraging women to get into engineering. Scholar; New River Valley Symphony; Horn En- Why ECE: “My idea of fun as a child was to semble. take apart the VCR.” Experience: 3 co-op rotations with Analog De- Fun experience: Making pancakes while vices, working with a high-speed converters watching a salsa practice before starting work group, learning much about ADCs, RF design, on a big project for class. “People here know lab skills, board-level design, hardware descrip- how to have fun, but still realize when it’s tion languages, lab and testing automation and more. time to work. They were really good pancakes.”

Ross Benjamin Clay Thomas Alan Cooper CPE ’09, Minor in Economics EE ’10 Raleigh, N.C. Oak Ridge, Tenn. Career aspirations: consultant or communica- Galileo Engineering Community; Student Engi- tions/systems product architect neers’ Council Publicity Committee; Intramu- Research: Spring 2008, pervasive computing. ral soccer; IEEE; WUVT Radio Corps. Summer 2007, Los Alamos National Laboratory. Memorable design projects: Sustainable En- “I developed a proof-of-concept program apply- ergy Design Project “helped me to better un- ing probabilistic buffer control to streaming derstand the current search for alternative video…working with researchers at LANL and sources of energy.” Contemporary Issue Re- VLC’s developers…Through this project I devel- search Project exploring the possibility of oped my programming skills and learned quite a using Helium-3 in fusion reactors as a source bit about the research and open-source of energy. communities.” Experience: IBM’s WebSphere Application Server System Verification Team; IT Consultant.

ware and electronics. He is also Dwayne A. Hawbaker(MSEE’91) James Hicks (Ph.D. ’03) pursuing a Ph.D. at Virginia Tech. Senior Staff Engineer; Johns Hop- kins Applied Physics Lab Hugh E. Hockett (BSCPE ’03) BRADLEY Timothy Gredler (BSCPE ’03) Matt C. Helton (BSEE ’01) Janie Hodges (BSCPE ’01) Christopher R. Griger (BSCPE ’02) Resident EE Senior Digital Hardware Engineer Coal Gasification Plant Spencer Hoke (BSCPE ’03) ALUMNI National Instruments Eastman Chemical Co. Software Engineer Austin, Texas Kingsport, Tenn. Garmin International Continued Projects have included frame grab- Kansas City, Kan. bers, high speed digital I/O Benjamin E. Henty (MSEE ’01) Hoke earned his MS in Brian Gold (BSEE ’01, MSCPE ’03) boards, SMUs, and DMMs. He has 2005 from Illinois with a thesis on Ph.D. Student; Carnegie Mellon a strong interest in renewable en- Jason Hess (MSEE ’99) wireless network protocol. Gold’s thesis work is on reliable, ergy and sustainable lifestyles. scalable multiprocessor computer H. Erik Hia (BSCPE ’99,MSCPE ’01) Russell T. Holbrook (BSCPE ’03) architectures. Alex Hanisch (BSCPE/Math ’03) Software Engineer Simulation and Modeling Group Hatteras Networks Andrew Hollingsworth BSCPE ’02 Jonathan Graf Joint Warfare Analysis Center Research Triangle Park, N.C. (BSCPE ’02, MSCPE ’04) King George, Va. Delivering broadband so- Ryan Hurrell (BSEE ’03) Senior Research Engineer lutions over existing copper facili- Electrical Engineer; Remotec, a Luna Innovations, Blacksburg, Va. Abigail Harrison (BSCPE ’04) ties to enable service providers to subsidiary of Northrop Grumman Graf is developing anti-tamper se- deliver transparent Metro Ethernet Mission Systems Division curity solutions for military soft- Jennifer J. Hastings (BSEE ’96) services. Knoxille, Tenn. 28 David C. Craven David C. Mazur CPE ’08 EE ’11 Winston-Salem, N.C. Pittsburgh, Pa. Hillcrest Honors Community; Corresponding IEEE Robotics Team, U.S. Soccer Refereee. Secretary, HKN; Pratt Engineering Scholar. Career aspirations: To own my own engineering Career aspirations: To design and create soft- firm ware for embedded systems Design project: IEEE Robotics has allowed me Memorable design project: a Microprocessor to experience real world engineering techniques System Design project that required using a as well as information taught in advanced level VGA controller on a small development board electronics labs. to make an animated screensaver. “It was the Why Tech: “The engineering program is very first major project to include a hard real-time strong and competes with the best in the na- requirement. I probably learned more about tion. Plus, the brotherhood of the Virginia Tech developing for embedded systems in that project than any other.” student body convinced me to attend Virginia Tech.”

Daniel Michael Hager Jacob Simmons CPE ’08; Minors in Math and Psychology CPE ’08 High Point, N.C. Smithfield, Va. Hillcrest Honors Community; National Merit Hillcrest Honors Community; dorm softball Scholar; Robert Byrd Scholar; captain, intra- coach. mural softball. Career aspirations: Robotics and embedded Career aspirations: NASA Mission Specialist; systems and/or digital control applying embedded software design to fighter Most rewarding design project: Designing the jets and defense sound system for a table-mounted train in Em- Research: Spring 2008, dynamic FPGA pro- bedded Systems. “I enjoyed experiencing the gramming. entire embedded systems design process from Experience: Lockheed Martin Information start to finish.” Technology Division developing software used Experience: Database technician, Northrop to install and maintain hardware at the Pentagon; Lockheed Martin Aero- Grumman Newport News, Summer 2007. Maintained existing record nautics, Marietta, Ga., involved with software for production and en- systems and designed new program for quick, reliable printing of mailing hancement of F-22s and C-130s. labels for drawing updates.

Zachary La Celle Chelsy Wynn Smidler CPE ’09 EE ’11 Lansing, N.Y. Lafayette, Ind. IEEE; National Society of Collegiate Scholars. Career aspirations: Work in a company like Study abroad: Spring 2008, Georgia Tech Lor- Rockwell Automation and be able to travel raine in France. around the world Career aspirations: Researcher in robotics. Why ECE: “I have always enjoyed learning about Experience: Build engineer, Autodesk, Inc., everyday electronic devices.” Summer 2007. Used scripts and IBM Rational Build Forge to control product builds; made code submissions. Most fun: “I really love my hardware classes on a daily basis, but most exciting so far was my first home football game. Coming from New York, I’d never experi- enced anything like it.”

Recent projects relate to participa- William B. Kuhn (Ph.D. ’95) Daniel L. Lough Stephanie Martin (BSEE ’04) tion in a new robot platform for Professor, EECE (BSCPE ’94, MSEE ’97, Ph.D. ’01) Columbia, Md. the British Ministry of Defense Kansas State University Warrenton, Va. Martin is working in electronic war- and a specialized platform for Lough recently published a book fare and is taking night classes at Yuma Proving Ground. Jeffery D. Laster (Ph.D. ’97) chapter on IEEE 802.11 Security Johns Hopkins toward an MSEE. Product Specialist, Analog, Mixed John Todd Hutson (BSEE ’93) Signal, and RF IC Cheryl Duty Martin (BSEE ’95) Michael Mattern (BSEE ’02) MentorGraphics,Richardson, Texas Head, Cyber Information Assur- Madiha Jafri (BSCPE ’03) He recently became a member of ance and Decision Support Christopher A. Maxey (BSCPE ’02) the Platinum Club at Mentor Applied Research Laboratories Daniel A. Johnson (MSEE ’01) Graphics. University of Texas at Austin Eric J. Mayfield (BSEE ’97) After earning a Ph.D. in 2001, Adam Kania (BSEE ’01) Charles Lepple (BSEE’99,MSEE’04) Martin worked for NASA on soft- Patrick McDougle (BSEE ’03) ware for crew working with ad- David A. Kapp (Ph.D. ’96) Jason Lewis (BSEE ’99) vanced life support automation. Brian J. McGiverin (BSCPE ’96) Since 2004, she has worked in in- Dimosthenis C. Katsis (Ph.D.’03) Joseph C. Liberti (Ph.D. ’95) formation assurance and security John T. McHenry (BSEE ’98, applications, including detecting MSEE ’90, Ph.D. ’93) David Kleppinger (BSCPE ’04) Zion Lo (BSEE ’94) computer activity relevant to in- Senior Electronic Engineer, Sr. SoftwareEngineer/Architect sider threat and automated secu- U.S. Department of Defense Paul A. Kline (Ph.D. ’97) IQNavigator, Colorado rity classification of text portions. McHenry’s interests are in high- speed network processing and Gregory Kozick (BSCPE ’03) FPGA design. 29 Bradley Scholars continued

Jerry Alwynne Towler Matt Welch EE ’08 EE ’09 Greer, S.C. Richmond, Ky. Student Technology Council IEEE; HKN Intramural Sports Chair, TBP,SEC, Co-op; Digital Receiver Technologies, Inc., writ- National Society of Collegiate Scholars, RHF ing software to test radio equipment. “I learned West Eggleston Hall Vice President; Galileo a great deal about radio communications … Learning Community. This was the first time I saw the actual results Experience: Summer 2008 will work for gas of various circuit configurations and transmis- turbine division of GE Energy. sion methods. As importantly, I learned what Why ECE: “Ever since I was little, I wanted to mistakes can be made and how they affect in- learn the reason why I could plug a device into tegrity of signal reception.” a power outlet and expect it to work.” Why ECE: Originally interested in MEMS and NEMS, now interests are shifting to controls, especially as related to ro- botics.

Paul Erik Nguyen Steven Schulz (MSEE ’91) East Tennessee State University (BSCPE ’98, MSCPE ’99) Tarnoff won the 2006-2007 ETSU David C. Schroder (BSEE ’05) ACM Outstanding Teacher Award, BRADLEY J. Eric Nuckols (BSEE’97,MSEE’99) which follows numerous awards Manager of Embedded Software Jeff Scruggs (MSEE ’99) over the years, including the Tri- ITT Advanced Engineering & Sci- Cities “40 under 40 Award” in ences; Advanced Communications Kashan Shaikh (BSCPE ’02) 2004. He recently published a ALUMNI System Develoment Group R&D Engineer free downloadable textbook, Com- Herndon, Va. GE Global Research Center puter Organization and Design Fun- Continued Niskayuna, N.Y. damentals. Neal Patwari (BSEE ’97, MSEE ’99) Shaikh earned his Ph.D. from Illi- David McKinstry (MSEE ’03) University of Utah nois in 2007. He focused on de- Daniel Tebben (Ph.D. ’06) Won 2007 NSF CAREER Award for veloping MEMS and microfluidic Garrett Mears (BSCPE ’00) RF-Sensing Networks for Radio To- systems for biotech applications. Rose Trepkowski (MSEE ’04) Head of Development mographic Environmental Imaging. Open Vantage Ltd., London Raymond A. Sharp (BSEE ’02) Christian Twaddle (BSCPE ’01) Joseph Allen Payne (BSEE ’00) Vinodh Menon (BSCPE ’02) Roger Skidmore (BSCPE ’94. Matthew C. Valenti (Ph.D. ’99) W. Bruce Puckett (MSEE ’00) MSEE ’97, Ph.D. ’03) Associate Professor, CS & ECE Michael Mera (BSEE ’03) Distinguished Innovator West Virginia University U.S. Army, Bangor, Pa. Yaron Rachlin (BSEE/Math ’00) Wireless Broadband Group Morgantown, W.V. Mera earned an MSECE from Pur- Researcher; Accenture Technology Motorola; Austin, Texas due and is doing R&D. Labs, Chicago, Ill. Skidmore co-founded Wireless Val- Wesley Wade (BSEE ’93) Rachlin earned his Ph.D. in 2007 ley Communications, which Mo- Carl Minton (MSCPE ’99) from Carnegie Mellon. torola acquired the firm in 2005. Kristin Weary (BSEE ’03) Lockheed Martin – Knolls Atomic John Morton (MSEE ’98) Christian J. Reiser (Ph.D. ’05) Jeff Smidler (BSEE ’98) Power Lab.

Stephen Nash (BSCPE ’03) Steve Richmond (MSEE ’01) Amanda (Martin) Staley Michael L. Webber (MSEE ’03) Senior Software Engineer (BSEE ’99, MSEE ’01) Lockheed Martin, Sykesville, Md. Jamie Riggins (BSEE/BSCPE ’04) Jason Wienke (BSEE ’02) Graham Stead (BSCPE ’93) Troy Nergaard (MSEE ’00) Pablo Max Robert (Ph.D. ’03) Thomas Williams (BSEE ’00) Tesla Motors; San Carlos, CA Douglas R. Sterk (MSEE ’03) Thomas W. Rondeau (BSEE ’03) Ph.D. s0tudent, Virginia Tech William J. Worek Michael H. Newkirk Postdoctoral Fellow (BSCPE ’99, MSCPE ’02) (BSEE ’88, MSEE ’90, Ph.D. ’94) Trinity College Dublin, Ireland Scott Stern (BSEE ’93) SAIC, Washington, D.C. Section Supervisor in the Air and Worek’s research is in biometric Missile Defense Dept. Thomas M. Rose (MSEE ’96) Samuel S. Stone (BSCPE ’03) analysis and evaluation, biometric Applied Physics Laboratory Radar Analyst fusion techniques, and network Johns Hopkins University Electro-Optics and Physics Group Anne (Palmore) Stublen communication protocols for RF Laurel, Md. Boeing Company (BSEE ’91) Newark, Del. networks. Newkirk is involved in analysis of University City, Mo. environmental effects on RF sys- Seema Sud (Ph.D. ’02) Kai Xu (BSEE ’95) tems, particularly radar and com- Jon Scalera (MSCPE ’01) munications systems, as well as David Tarnoff (MSEE ’91) Jason Jon Yoho (Ph.D. ’01) testing, upgrading radars, and RF Amy Schneider (BSCPE ’03) Assistant Professor propagation modeling. Computer & Information Science Gregory A. Zvonar (MSEE ’91) 30 Silicon micro device may help ECE does about $25 million of diagnose, treat cancer research yearly, Co-culture of two cell lines. in applications ranging from cancer research

toRESEARCH wind power.

Fibroblast cell attachment inside etched features. team from ECE’s Microelectromechanical surfaces and inside the microchambers regardless System (MEMS) Laboratory has developed a of microchamber depth, according to Masoud A3-D silicon microstructure that has potential Agah, director of the laboratory. The cancer cells, to detect breast cancer cells and to separate cancer however, typically did not grow on the flat sur- cells from other cell types. faces when there were microchambers having The devices consist of arrays of microcham- depths of 78 and 88 micrometers. bers connected with channels and were fabricated The microdevices have potential use in diag- using a single-mask one-pass etching process de- nosing cancer, determining prognosis, and in test- veloped in the laboratory (see p. 12.). When cul- ing the reaction of an individual’s cancer cells to tured on the devices, breast cancer cells stuck to different drug treatments. Agah is working with the shallow curved walls, but the normal fibrob- Dr. Jeannine Strobl from the Virginia College of last cells stretched inside the channels, avoiding the Osteaopathic Medicine and Mehdi Nikkhah, an curved walls. graduate student in mechanical engineering. For The fibroblast cells grew on both flat silicon more information, visit www.ece.vt.edu/mems/. Safety-critical embedded software: correct by construction?

run by concurrent ratory Institut National de software systems re- Recherche en Informatique et acting to a myriad en Automatic (IRISA) on a spec- sensor inputs. ification methodology called The problem, Polychrony, which allows one to he says, is verifying specify the concurrent computa- the correctness of an tions. entire system func- Based on Polychrony, the tioning together. He IRISA team and Shukla’s FER- is working with the MAT lab have previously pro- hat do a Renault car and Air Force Research Lab to gen- p o s e d an AirBus 380 have in erate software that is correct by v a r i o u s Wcommon? “Millions of construction for its specifica- m e t h o d - lines of embedded software run- tions and can generate multiple ologies for com- ning in networked communica- sequential software components posing existing tion” is the reply from Sandeep to work correctly across a net- components to Shukla, director of Virginia work. They also may be multi- create new designs Tech’s FERMAT lab. Safety- threaded, he says. of systems-on-a-chip. critical systems, such as those on Shukla has been working For more information, visit cars and jets, are increasingly with the French National Labo- http://fermat.ece.vt.edu. 31 FACULTY Research laboratory information Peter Athanas Center for Embedded Systems in Critical Applications Dong Ha www.cesca.centers.vt.edu Michael Hsiao FERMAT: http://fermat.ece.vt.edu VLSI & Chao Huang PROACTIVE: www.proactive.vt.edu Tom Martin VT VLSI for (VTVT) DESIGN Patrick Schaumont www.ee.vt.edu/~ha/research/research Sandeep Shukla AUTOMATION Secure Embedded Systems Joseph Tront www.ece.vt.edu/schaum/research

ECEs spot FPGA security weakness; Finding may lead to new chip ID

esearchers in Secure Em- but Patrick Schaumont's group bedded Systems have has shown that state-dependent Rdemonstrated a previously circuit effects are also a source of unremarked security hole in em- leakage. “Because of the diffi- bedded systems — leaving pro- culties of mass producing intri- prietary data available to thieves cate microchips, every single

hitn O’Connor Christina and hackers using side channel chip is a little bit different,” attacks. Schaumont explains. “Each in- Side channel attacks use dividual chip leaks differently.” non-intrusive monitoring of se- The good news is that the cure hardware to unlock the se- same findings can be used to de- crets of an embedded system. By velop unique identifiers for indi- Using inexpensive, easily available measuring the power consump- vidual chips. tools — an ocilloscope and MATLAB, tion for example, hackers are “We want to quantify the Zhimin Chen demonstrates how to able to infer the internal activi- differences and see if this could crack the security key on a Spartan ties of the system including in- help with applications such as FPGA board that is used in Virginia ternally hidden security keys. automobile identification, or for Tech computer engineering courses. Conventional wisdom says software firms to track their li- “This is cheap equipment,” says Assis- that a glitch-free masked circuit censes,” he says. tant Professor Patrick Schaumont. “If is good protection against these For more information: we can do this, anybody can.” common power-based attacks, www.ece.vt.edu/schaum/research.html

FACULTY Left:Mohamed Lynn Abbott Saleh tests a Peter Athanas system that Virgilio Centeno COMPUTER measures the Mohamed Eltoweissy texture of pave- Michael Hsiao SYSTEMS ment. Below left: Chao Huang Laboratory and group information Cracked pave- Mark Jones ment. Below: Tom Martin e-Textile Laboratory computer repre- Leyla Nazhandali www.ccm.ece.vt.edu/etextiles/ sentation of the Jung-Min Park cracked texture. Cameron Patterson Configurable Computing Laboratory JoAnn Paul www.ccm.ece.vt.edu Paul Plassmann Real Time Systems Laboratory Binoy Ravindran Patrick Schaumont www.real-time.ece.vt.edu Sandeep Shukla Joseph Tront Chris Wyatt Yaling Yang

32 RESEARCH Improving night vision VT software technique speeds up with new super-res processing development of new analysis apps he low-resolution images produced by infrared systems can A GA-based integrated sys- make it difficult for night-vision users to estimate distances or tem model (ISM) of Staten Tidentify far objects. “Resolution enhancement” attempts to ad- Island goes from the trans- dress these problems by converting several low-quality images into mission level down to every a single, higher-quality version. Unfortunately, conventional meth- customer. The two types of ods of reconstructing these low-quality images are computationally views, geographic and intense, making them too expensive or too slow for real-time, af- schematic,are concurrently fordable use. driven by a GA analysis engine. Researchers in ECE’s Computer Vision Laboratory have devel- oped a new resolution enhancement technique based on super-reso- lectric utilities, national laboratories, universities, and the de- lution reconstruction (SRR). The new method is fast and memory partment of defense are using a Virginia Tech software tech- efficient, providing performance comparable to previous techniques Enique to quickly develop new analysis applications at low cost. but with dramatically reduced computation requirements, accord- The technique, called generic analysis (GA), was developed by ing to Ph.D. student Jae Cha and his advisor, Lynn Abbott. Robert Broadwater in the 1980s and is becoming more widely used Their closed-form, one-pass method is much faster than exist- each year. GA can handle models involving millions of components ing iterative approaches. In several experiments, they demonstrated and has been successful analyzing complex systems, including down- a 10-fold speed-up in computation time. The speed, combined with town electric supply systems of St. Louis and New York City. Due low memory requirements, make this method suitable for use in a to the speed of the technique, the entire St. Louis downtown elec- low-cost distance-estimation system for infrared applications. tric supply system solves in about one second. FACULTY GA is based on the generic programming paradigm, which Lynn Abbott SOFTWARE & places data in containers. In GA, the container corresponds to the Robert Broadwater system model. All algorithms access data in the container using iter- Mark Jones MACHINE ators. In GA, the same algorithm can be used across different types Pushkin Kachroo of models, or different algorithms can be applied to the same model. Cameron Patterson INTELLIGENCE New data and analysis can be attached to the model without af- Paul Plassmann fecting any existing functionality. Furthermore, a new analysis func- For more information: Binoy Ravindran tion can make use of any existing analysis functions attached to the Sandeep Shukla Computer Vision Laboratory: model. “With GA, algorithms written by different people can col- Yue Wang http://vision.ece.vt.edu laborate through the model, in the way teams of people collaborate,” Chris Wyatt he explained. Jason Xuan With GA, he said, personnel throughout a large enterprise can Using computer vision share a common system model across many functions — from plan- for a smoother ride ning and design to real-time operation and control. “With GA, the he texture of the roads we drive is a factor in the noise, comfort, vision is that the model becomes a and safety travelers experience. Measuring the pavement tex- reusable, maintained unit Tture, however, entails interrupting traffic and the need for traf- throughout the life of the plant.” fic control measures — while providing only a limited sample of the road. GA can analyze systems Ph.D. student Mohamed Saleh is developing a stereo vision sys- where the system model changes, tem that can provide continual road texture measurements at high- such as occurs in cascading power failures. Four of the 10 largest way speeds over an entire area and will not interrupt traffic. U.S. electric utilities are using GA. ECE Ph.D. students Kevin Rus- Saleh’s system uses two cameras placed side by side capturing sell, Lynn Feinauer, and David Kleppinger are solving reconfigura- the same image, yielding a slightly different views of a 3-D scene. tion for restoration problems for cooling water, fire main, and The images are processed, aligning the epipolar lines and perform- electric power systems on naval ships. ECE’s Kwa-Sur Tam is using ing edge detection. A matching algorithm identifies the candidate GA for an economic analysis of the Detroit Edison electric system. correspondence and produces a 3-D image, allowing depth measures Researchers in civil and environmentalengineeringaremodeling crit- of the area to be examined. ical infrastructure systems for the U.S. Army, including sewage, gas, “The benefit of an area measurement, instead of a thin longitu- and real-time potable water. Georgia Tech and the West Virginia dinal line, will give us better characterization of the road surface,” University are using GA modeling, as are several national laborato- says Saleh, who is working with advisor Lynn Abbott. “This is ries and overseas power companies. needed to better determine most tire-pavement interactions, such as friction, noise, splash and spray, rolling resistance, and tire wear.” 33 Setting limits for

FACULTY Networks Propagation cognitive radio networks Luiz DaSilva Gary Brown any researchers expect that as cognitive WIRELESS Thomas Hou William Davis radio (CR) technology matures, it will Tamal Bose Scott Midkiff Steven Ellingson Mplay a pivotal role in wireless mesh and ad Charles Bostian Jung-Min Park Majid Manteghi Michael Buehrer hoc networks, according to Tom Hou, an asso- Yaling Yang Sanjay Raman Claudio da Silva ciate professor of ECE. Sedki Riad Allen MacKenzie Fiber Comm “Due to its unique characteristics in spec- Ahmad Safaai-Jazi Tim Pratt Ira Jacobs trum usage, a CR network differs significantly William Tranter from the existing multi-channel, multi-radio net- Optics Amir Zaghloul T.-C. Poon work,” he says. He was recently awarded a two- DSP year grant from the National Science Foundation Louis Beex NeTS program to develop network theoretical Amy Bell COMMUNICATIONS bounds and performance limits for future CR Lamine Mili Laboratory and group web sites: networks. “Such efforts are not only of theoret- Jeffrey Reed Wireless@Virginia Tech: ical interest, but also offer fundamental under- VLSI Circuits www.wireless.vt.edu standing of the potential and limits of such Peter Athanas Digital Signal Processing & Communications Lab: networks, as well as provide performance bench- Dong Ha www.ece.vt.edu/fac_support/dspcl marks for the design and evaluation of distrib- Michael Hsiao uted algorithms and protocols.” Networks for the GPS-challenged single receiver in a dense forest does not get enough informa- By range-finding between themselves, the nodes will know each tion to determine its location using the GPS system, which re- other’s relative location and be able to precisely compute the lati- Aquires a lock on four different satellites. Obstructions in the tude and longitude for each node. forest (trees to most people) typically prevent receivers from com- In an effort to characterize the EM propagation and GPS per- municating with more than one or two satellites at any single time. formance in forest environments, a team of graduate and undergrad- A Wireless@VT effort, headed by Michael Buehrer, an associ- uate students measured 93 different locations in four different forest ate ECE professor, is developing outdoor sensor network technol- environments. More than 1400 measurements were recorded in light ogy that enables receivers to share GPS information and determine brush and light, medium, and dense forest situations. their own location. Nodes will share their limited GPS information The undergraduates were funded under the National Science to calculate a known coordinate for at least one node in the network. Foundation (NSF) Research Experience for Undergraduates (REU) program. Undergraduate students involved were Alyse Bowers, Kyle A student team took more Forrester, Chris Hutchens, Jason McKillican, and Brian Sarbin. than 1400 measurements Their work was presented in a paper at the 2008 IEEE Wireless to help characterize the EM Communications and Networking Conference. propagation and GPS per- The team was led by postdoctoral research faculty member formance in forests. Chris Anderson and a graduate student team of Haris Volos, Bradley Fellow Chris Headley, and Tao Jia. Anderson is now an assistant pro- fessor of ECE at the United States Naval Academy.

34 RESEARCH Wireless students take tops Reasoning and learning in in international competition wireless networks CE graduate students took receiver, and successfully trans- CE communications and networking researchers are investigat- top honors during the 2007 mitting data accordingly. ing reasoning and learning mechanisms in an adaptive wireless ESoftware Defined Radio Tech’s other team of grad- Enetwork. Forum conference in November. uate students, advised by Carl Virginia Tech is part of a team led by BBN Technologies and Teams representing Wire- Dietrich, won the “Best Design” funded by DARPA’s Wireless Network after Next (WNaN) pro- less@Virginia Tech participated in the Smart Radio Challenge gram in the international Smart Radio for its approach to the problem WNaN is developing technology to provide low-cost commu- Challenge. Tech was the only of spectrum access for first re- nications for the military to communicate with each soldier and de- school with two teams among sponders. vice in a tactical situation. The program aims to develop handheld the finalists. Each group had to Software defined radio de- wireless nodes that can be used to establish dense ad hoc networks design, develop, and test a soft- vices use software rather than and links to the information grid. By working around the limita- ware defined radio (SDR) in a traditional dedicated hardware tions of the low-cost nodes that form the network and by using the way that would solve a specific to define and modify the way rich interconnection fabric created by dense deployment, the WNaN problem. they perform signal processing network should provide reliable battlefield communications at low A team of eight graduate for transmission and reception. system cost. students, advised by professor This technology is used in two- ECE faculty members involved in the effort include Luiz Charles Bostian, won the com- way communications devices by DaSilva, Allen MacKenzie, R. Michael Buehrer, Charles Bostian and petition’s grand prize by devel- tactical military forces and Jeffrey Reed. oping a software defined radio emergency responders, as well as capable of finding available spec- in the development of wireless Wireless@VT joins NSF’s WICAT trum within a pre-defined band, networks that provide Internet rendezvousing with an intended services to rural areas. amal Bose was named Virginia Tech’s site director for the multi-university Wireless Internet Center for Advanced Tech- Tnology (WICAT) to collaborate with industry research part- Automated design for networks ners to create flexible, efficient, and secure wireless networks. etworks of the future will evolve instead of being designed by WICAT, an NSF center, includes teams from Polytechnic Univer- engineers, according to Yaling Yang, an assistant professor of sity, the University of Virginia, Columbia, and Auburn Univer- NECE. She is leading a Virginia Tech effort to replace today’s ad sity. WICAT’s mission is to create networks that satisfy the needs of hoc, manual process of network design with automatic system de- businesses and of consumers. sign and adaptation. Virginia Tech’s research contributions to the center are focused “Traditionally, network engineers have designed network sys- on cognitive radio-based wireless networks, with efforts in software tems, based on complex collections of objectives, policies, princi- defined radios (SDR), cognitive radios, cognitive network testbed ples, and past experiences, she says. “The design process is top-down implementation, theoretical foundations of wireless communica- and based on a set of over-simplified assumptions about the opera- tions and wireless systems modeling and simulation. Virginia Tech’s tion environments and performance objectives.” Because of limited part of the award amounts to $350,000. human experience and capability, this manual design process makes it impossible to exploit and evaluate the entire design space for net- work systems, resulting in extreme challenges for identifying the NETWORKING best designs and promptly responding to network environment Laboratory and group websites: changes, she explains. Advanced Research in Information Assurance and Security: Instead, she says, a network could be automatically assembled www.arias.ece.vt.edu from a set of reusable “genes” and tested in its actual environment. In this scenario, a gene is a small piece of computer code that imple- Laboratory for Advanced Networking: www.irean.vt.edu/lan ments a particular design for a small part of a network component, such as an intrusion detection system, a routing protocol, or a trans- FACULTY Scott Midkiff mit power adaptation strategy. The selection of genes in the auto- Luiz DaSilva Leyla Nazhandali matic process would be based on performance analysis and guided by Mohamed Eltoweissy Jung-Min Park an evolution process based on interoperability and compatibility the- Thomas Hou Binoy Ravindran ory, optimization theory, and game theory. Allen MacKenzie Yaling Yang

35 New sensor technique more than doubles temperature capabilities esearchers in the Center for Photonics Technology are develop- combination of etching and bonding techniques applied to single- ing a new process to manufacture robust pressure sensors that crystal sapphire components. The result is a Fabry-Perot cavity with Rcan operate in temperatures up to 1500°C and in extremely a thin diaphragm, which flexes in response to ambient pressure harsh environments. Current pressure sensing technology is limited changes. The sensor can be made smaller than 1 cm. wide. to about 600°C. Sapphire is an extremely hard, corrosion resistant crystal with “This technology could be used to monitor real-time pressure a melting point over 2000°C, which makes it an ideal material for fluctuations in high temperature furnaces, jet engines, combustion high-temperature, harsh environments, he explained. It is immune engines, chemical reactions, or corrosive environments,” said to electromagnetic interference, and because sapphire is a good insu- Bradley Fellow Evan Lally, who is on the development team. lator, the sensor could be used in applications where electronic pres- The all-sapphire pressure sensor is constructed through a novel sure sensors could cause an ignition hazard.

FACULTY Scott Bailey Buzz Be Gone Charles Bostian Gary Brown UWB reduces C. Robert Clauer cell interference with William Davis Steven Ellingson ELECTROMAGNETICS hearing aids Louis Guido he nation’s 5.6 million hearing aid users some- Ira Jacobs For more information: times get too much buzz from interference by Brent Ledvina Tnearby cellular phones. Some parts in the hear- Majid Manteghi Center for Photonics Technology ing aid act as unintended antennas and couple the en- Kathleen Meehan www.photonics.ece.vt.edu Hardus Odendaal ergy from phones to the hearing devices. The Center for Space Science and Engineering Research coupled energy is demodulated in the phone’s ampli- T.-C. Poon www.space.vt.edu Sanjay Raman fier circuits, producing the irritating buzz hearing aid Sedki Riad Time Domain & RF Measurement Laboratory wearers know so well. Ahmad Safaai-Jazi www.tdl.ece.vt.edu ECE graduate student Taeyoung Yang says the Wayne Scales Virginia Tech Antenna Group solution could be a new antenna. He proposes solving Anbo Wang http://antenna.ece.vt.edu this problem with a UWB antenna that minimizes Yong Xu near-field radiation from the phone as well as interfer- Amir Zaghloul ence to hearing aids, pacemakers, and other medical devices. Yang, with advisors William Davis and War- ren Stutzman, designed an antenna and installed it on a cellular phone mockup. The low-Q (ratio of total non-radiating energy to average radiated power per radian) antenna has low non-radiating stored energy in the near field, reducing interference with hearing aids and potential power absorption by the human head, while not reducing far field performance. His project, entitled ‘Cellular Phone and Hearing Aid Interaction: An Antenna Solution,’ won a na- tional honorable mention in the 2007 FEKO student competition for simulation techniques used to solve electromagnetic problems. He also received Virginia Tech’s Torgersen Graduate Student Research Excel- lence Award for scientific originality and contribu- tion.

Left: Cell phone mockup with conventional antenna and proposed UWB antenna (right).

36 RESEARCH DALI on the dark side stronomers have long dreamed about putting telescopes on the far side of the moon, away from Earth’s turbulent ionosphere Aand torrent of radio signals. In the moon’s radio-free shadow, radio telescopes might possibly pick up faint signals from the early universe that could not be otherwise detected. ECE’s Steve Ellingson is part of a Naval Research Laboratory team fleshing out ideas for rolled-up radio antennas that would pop open after being dropped on the lunar surface for transmitting data and for taking advantage of the planned presence of astronauts on the moon around 2019. The team wants to build radio telescopes (antennas) that can capture signals at the very long wavelengths generated by events that Phoebe’s Field project lets kids occurred within hundreds of handle scientific concepts thousands — as opposed to bil- Blue sky is simulation lions — of years after the big of what telescope sees n international team of educators and professionals based at Vir- bang. The universe consisted at radio wavelengths. ginia Tech is working on giving middle-schoolers innovative then of still-dark matter, hydro- Aways to learn scientific concepts, such as electromagnetic and gen and helium. Efforts to test acoustic fields. Their goal is to encourage interest in science among theories about the Universe’s ori- children, especially girls. ECE faculty member Steve Ellingson is part gins would benefit from the kind of the team, which is led by Mitzi Vernon of the School of Archi- of data a moon-based radio tele- tecture and Design and includes eight other collaborators. scope could provide. The effort, which includes a children’s book and a traveling ex- The team, which includes hibition, is called Phoebe’s Field and is targeted especially for girls, researchers from Berkeley, the who often lose interest in science at adolescence. University of Colorado, Har- The exhibition will use metaphors in nature to explain com- vard, and Yale, is working under plex concepts, such as electromagnetism. As they tour the exhibi- a $500,000 NASA-funded plan- tion, students see, hear, touch, and carry out physical activities in ning grant as part of the Dark fields usually beyond their perception. A quest storyline captures the Ages Lunar Interferometer An artist’s conception of one of the student’s attention and focuses their interest in concepts. (DALI) project. The team has re- antenna arrays comprising the Ellingson is contributing to the development of the electromag- cently merged with a similar ef- radio telescope. The antennas are netic field exhibit, which deals with the concept of electromagnetic fort led by MIT. The Dark Ages printed on a thin material which is signals such as those found in cell phones. He is also working on an refers to the time after the initial rolled out from a central electron- RFID-based system that will allow new forms of interaction be- universe explosion and before ics hub that contains receivers and tween the exhibits and the visitors. Visit: www.phoebesfield.org. stars and galaxies formed. communication gear. .1 micron precision hen the measurable difference between two their lengths are monitored as the fiber tips are equal fiber path lengths in a fiber coupler ground down. Wcould not exceed 5 micrometers, re- The team reports they expect their polishing searchers in the Center for Photonics Technology system to achieve 0.1 micron path length equaliza- designed a new polishing technique. tion. Bradley Fellow Evan Lally and undergradu- Having a fiber coupler with exactly equal ate Tyler Shillig have been working on a special length output arms is critical to the operation of a white-light interferometry technique to monitor system they are developing to image small rock the exact optical path length difference between and sand particles in asphalt. The project is spon- two coupler arms. The two lengths of fiber are sored by the National Cooperative Highway Re- placed in a precision adjustable polishing jig, and search Program.

37 The growing national ELECTRONICS interest in sustainable SUSTAINABLE BUILDINGS FACULTY Sanjay Raman homes and alternative Masoud Agah Anbo Wang energy sources has Dushan Boroyevich Fred Wang Solar photovoltaic William Davis Ming Xu spurred several research Louis Guido Sedki Riad Entertainment efforts tackling the tech- and data systems Robert Hendricks Amir Zaghloul nology problems from Lighting Chao Huang Kwa-Sur Tam Jason Lai Krishnan Ramu different perspectives. Fred C. Lee Douglas Lindner G.Q. Lu Joseph Tront Kathleen Meehan Yong Xu HVAC Franusich Dave

Khai Ngo Energy Hardus Odendaal Living management Appliances Marius Orlowski Plug-in hybrid For more information: laboratory Center for Power Electronics Systems: www.cpes.vt.edu for sustainable building research Future Energy Electronics Center: he Center for Power Electronics Sys- rooms for normal daily functions. www.feec.ece.vt.edu tems (CPES) is developing two test- The experimental laboratory will be Microelectronics, Optoelectronics and Nanotechnology (MicrON): Tbed/laboratories for its research in powered by a power-system testbed supplied www.micron.ece.vt.edu power electronics energy management of by multiple renewable energy sources, in- sustainable buildings. cluding a 3.5 kW turbine generator, a 5kW ECE invention named The center is developing a “living lab” PV solar panel system, lithium-ion battery to R&D Top 100 to provide a testbed for the energy systems bank for energy storage, and a plug-in hy- of a sustainable home of the future and a brid car with bidirectional energy flow. G.Q. Lu’s invention of nanoTach was named one of the 100 top inventions DC-based electric power system. The electrical system has both a high- of 2007 by R&D Magazine. NanoTach is Four rooms in the CPES laboratories voltage DC bus for HVAC, simulated a nanoparticle paste made of silver for in- are being converted into a conference room, kitchen loads and major appliances and a terconnecting high-power electronic de- library/lounge, kitchen, and utility room. low-voltage bus for telecommunications, vices. It turns silver when heated. Students, faculty, and staff will use the computers, and LED lighting.

FreedomCAR:Seeking 98.5% efficiency Jason Lai, director of the Future Energy reliability issues, according to Lai. “A four- Research Center, is heading a $2.7 mil- inch silicon wafer is $25 and a two-inch SiC Jlion effort to develop a power electronics wafer is $950. A three-inch SiC wafer is inverter for the Department of Energy Free- $5000,” he says. domCAR project. The FreedomCar is a Lai’s team is pursuing two key issues: multi-year effort to develop technologies soft switching technology and advanced that enable the adoption of first gas/hybrid, power module packaging, which he is part- then fuel cell/hybrid vehicles. nering with Powerex to develop. The Vir- Lai’s is the only university-based team ginia Tech team is developing the soft- of the five involved in the drive train devel- switching technology, trying to get the effi- opment. The target for the project is to be ciency higher than 98.5 percent. “We can get able to run the entire drive train at 105°C at it to 99 percent with the use of more silicon, the cost of $8.50 per kW. which we don’t want to do obviously for the “With today’s technology, it is practi- economical reason.” Jason Lai (right) demonstrates previ- cally impossible to run electronics at that Lai’s team has previously achieved ous milestone efficiencies to Bradley temperature with a reasonable cost,” he says. record-breaking efficiency on other projects, Fellow Parrish Ralston, who is charac- His goal is to develop the system that can run including a 97 percent efficient isolated DC- terizing fifth generation transistors with consumer-grade silicon in order to keep to-DC converter for fuel cells, developed in for the FreedomCAR project. the cost down. The other teams are using sil- 2005. “If we cannot achieve the 98.5 effi- icon carbide (SiC), which can handle the ciency, nobody can,” he says. “That’s why temperature, but is very expensive and has we won the project.” 38 RESEARCH Storing solar energy for the swing shift FACULTY Lamine Mili team of Virginia Tech researchers is developing the technology POWER Robert Broadwater Saifur Rahman to store solar energy in fuel cells for when the sun goes down. Virgilio Centeno Kwa-Sur Tam For more information: Jaime de la Ree James Thorp A“Electricity generated via solar energy peaks in mid-day, but Power IT Laboratory: Yilu Liu power consumption at home is typically concentrated from evening www.powerit.vt.edu to early morning,” says Kathleen Meehan, an assistant professor and principal investigator on the project. Solarized fuel cells would enable energy produced in daytime to be stored for evening and cloudy-day use, while eliminating the need for batteries, she explains. Energy would be stored as hydrogen and oxygen through water electrolysis. When the solar system cannot produce enough energy for the load, the fuel cell would be used. Technology improvements are needed, however, before such systems are affordable and reliable — and the expertise to develop them is at Virginia Tech, she says. The team, which includes electri- cal, materials, chemical, and mechanical engineers is working on de- veloping advanced solar cells with nanoscale conversion films; power tracking systems to divide solar power generated between the load and the electrolysis system, nanoscale catalysts to improve solar en- ergy conversion to hydrogen optimized power conversion, and power conditioning for household and plug-in hybrid electric vehi- cle loads. Researchers under the direction of Virgilio Centeno are In addition to Meehan, principal investigators on the project are using the testbed in the Power Engineering Laboratory ECE’s Jason Lai, G.Q. Lu, and Lou Guido, along with Richey Davis to test the dynamic performance of Phasor Measure- of chemical engineering and Douglas Nelson of mechanical engi- ment Units (PMU). neering.

ECE team joins China-sponsored A new wind turbine now sits Energy Security Group atop Whittemore Hall, ational Academy of Engineering members Arun Phadke installed by the Center for and James Thorp are part of a Chinese funded research Power Electronics Systems Nteam directed to improve the protection and security of (CPES) to support research in the worldwide, interconnected electric power grid. China’s sustainable buildings. Ministry of Education and State Administration of Foreign Ex- The turbine is a vertical perts Affairs is sponsoring the five-year, $1.2 million project, axis turbine, which has ad- called the “Expertise-Introduction Project for Disciplinary In- vantages in small places. novation of Universities.” The turbine is effective in Phadke and Thorp are both leading experts in power sys- winds as low as five miles tem digital protection. Traditionally electric power networks per hour and can tolerate have used the computer and communication networks in a va- winds exceeding 100 miles riety of critical applications. However, researchers are looking per hour. The design is quiet at new configurations of power, communication and computer and friendly to birds, who networks that could be more easily controlled and protected see it as a solid object and for optimum security, economy, and performance. avoid it when it is moving. Christina O’Connor 39 Playing well with others — autonomously irginia Tech air, surface and ground au- first attempt,” said ECE’s Dan Stillwell, whose tonomous vehicles showed their teamwork team developed the ASV and control algorithms. Vability in a reconnaissance demonstration at ECE’s Chris Wyatt lead development of machine the U.S. Navy’s 2007 AUVFest. vision algorithms for the ASV. The autonomous surface vehicle (ASV) de- In another demonstration, Virginia Tech’s ployed first, and patrolled on a river through pre- high speed autonomous underwater vehicle (AUV) programmed way-points. Because the AUV has demonstrated its high-speed capability. In just 40 limited field-of-view, the “Rascal” unmanned air seconds, it launched and covered more than 200 vehicle (UAV) then flew over the operating area, meters at about 10 knots. to look for potential objects of interest. It detected A platoon of other AUVs, including the VT the targeted object, localized it, and sent the coor- 475 AUV, demonstrated coordinated motion con- dinates to the ASV, which then changed its route trol and adaptive environmental sampling capabil- to pass around the object for close-up inspection. ities. For environmental sampling, an AUV At the same time, Tech’s unmanned ground vehi- detected and then mapped the outflow of a waste Reconnaissance demonstra- cle, “Rocky,” patrolled the shore and maneuvered water treatment plant that flows into St. Andrew tions of the ASV, Rascal UAV, a to keep the object in its camera’s field of view. Bay near Panama City, Fla. The AUV detected and platoon of other AUVs, and the The demonstration was a collaboration be- ran through the plume. When the AUV recog- unmanned “Rocky” by Virginia tween Virginia Tech autonomous vehicle re- nized that it had returned to the ambient environ- Tech and the U.S. Navy Post- searchers and the U.S. Navy Postgraduate School ment, it turned back on a different trajectory. The graduate School. (NPS). “Despite this being our first opportunity AUV repeated the process many times and con- for Tech and NPS to operate all systems simultane- structed a map of the plume and estimated center ously, the demonstration worked perfectly on the of the plume. (www.ascl.ece.vt.edu)

Unraveling the environmental and genetic factors of common diseases ue (Joseph) Wang and Jason Xuan are applying machine learn- Bio-imaging Laboratory. “To understand what combination of fac- ing to understanding the complex interactions between envi- tors triggers these diseases and how they each contribute is an enor- Yronmental and genetic factors in common diseases. mous computational task.” Many diseases result from a complex interaction of multiple en- The diseases are caused by many small effects, which are hard to vironmental and genetic factors and since the sequencing of the see in the data, he explained. The effects are not just complex, but human genome, researchers have been gathering genetic data associ- also nonlinear. “Not everybody has all the effects. Taken together, ated with common diseases. However, it is largely unknown how however, all the small effects can equal disease.” specific variations in a person’s genes interact with each other to in- The team plans to develop parallel and economics portfolio crease the propensity for any given disease. computing techniques to meet the computational challenges of the Researchers have started using genome-wide association stud- problem. ies (GWAS), — hailed by Science magazine as the breakthrough of Wang and Xuan have received a grant from the National Insti- the year — to identify the risk associated with each factor. GWAS tutes of Health (NIH) as a part of the Gene and Environmental Ini- studies involve using arrays that can compare 500,000 factors against tiatives (GEI) to pursue the effort, jointly with Wake Forest thousands of people. University School of Medicine and Pennsylvania State University “GWAS studies generate huge datasets on these genetic factors,” College of Engineering said Wang, who directs ECE’s Computational Bioinformatics and For more information, visit www.cbil.ece.vt.edu. 40 RESEARCH

In May 2007, ECE Professor Krishnan Ramu sold his five- Jumping head-first year-old Panaphase Technolo- gies to Magnetic Torque International of Reston, mak- into the unknown ing a successful technology hen working on a research project transfer of intellectual prop- erty in the field of variable re- in ECE’s Digital Signal Processing luctance and permanent WResearch Laboratory this spring, magnet electric motors and Gary Wheelock (EE ’08) found that div- drives. ing head-first into a project can get messy. With funding from BAE Systems, Whee- lock has been working with a DSP board to develop a BPSK (binary phase-shift keying) transmitter and receiver and FACULTY measure the bit-error-rate of the system. William Baumann Wheelock said his biggest challenge Christina O’Connor A.A. (Louis) Beex SIGNALS, was overcoming his lack of specific back- Pushkin Kachroo ground. “I dove right in head-first with no good starting place,” he Douglas Lindner SYSTEMS said. “Things got messy, so I backed off and decided to implement Krishnan Ramu a simple design based on my experience, then build from that.” Daniel Stilwell AND CONTROLS Yue (Joseph) Wang Developing the transmitter required dealing with issues in sam- Chris Wyatt pling, carrier recovery, filtering, synchronization, and bit detection. Jason Xuan “There are multiple ways to implement a receiver — all ranging in complexity.” Before completing the project, he hoped to develop a For more information: synchronous receiver and possibly implement pulse shaping to help Autonomous Systems & Controls Laboratory: limit bandwidth. www.ascl.ece.vt.edu As a result of his experience, he feels more confident to tackle an unknown project. But the most fun, he says, was finally under- Digital Signal Processing Research Laboratory: www.dsprl.ece.vt.edu standing the details of the board and the system. “Once you under- stand it, it’s more fun. You can play around with the system, tweak it, add parts: basically make it your own. This is almost mine.” Getting comfortable with mutagens and E. coli or her research in modeling and param- and isolated it,” she said. “We were hoping pen between giving someone a design for an eter estimation of small gene networks, to get data for a system model.” experiment and the data that come out.” Bradley Fellow Rebecca Shelton needed She found some interesting differ- F O’Connor Christina a firm understanding of the strengths and ences between an EE laboratory and a bi- weaknesses of the data involved. This led to ology wet laboratory. “In engineering, spending a couple months in Jean Pecoud’s we don’t set things up and wait “wet” laboratory at the Virginia Bioinfor- overnight to see if they grow. We just matics Institute (VBI). turn equipment on.” She also gained an Her task was to prepare DNA con- appreciation for good laboratory tech- structs for testing. Putting the constructs to- nique. “Not only is it surprisingly hard,” gether involved using restriction enzymes to she said, “but I also had to get comfort- digest, or cut, the pieces first, she explained. able working around mutagens and what The digestion was then inserted into a gel you think of as potential disease-causing made with agar, merged in a buffer, and organisms like E. coli.” electrified — a process called electrophore- Her biggest lesson, however, was a sis. Different sized DNA fragments, which new appreciation for data. “I thought I are negatively charged, move at different knew where data comes from and what speeds toward the anode. “We then com- variables go into it. In the lab, however, pared the fragments with a constant to select you see where the errors can come from. the size we needed. We cut it from the gel You can see all the things that can hap- 41 2006 PH.D. DEGREES 2007 AWARDED Akbar, Ihsan Ali Collins, Gustina Bernette Lee, Unghee Neel, James O'Daniell Statistical Analysis of Wireless Sys- Design, Fabrication and Testing of A Proactive Routing Protocol for Analysis and Design of Cognitive tems Using Markov Models Conformal, Localized Wafer-Level Multi-Channel Wireless Ad-Hoc Radio Networks and Distributed Committee Chair: Tranter, W. H. Packaging for RF MEMS Devices Networks Radio Resource Management Committee Chair: Raman, S. & Committee Chair: Midkiff, S. F. Algorithms Al-Nasur, Sadeq Jawad Lu, G. Q. Committee Chair: Reed, J. H. New Models for Crowd Dynamics Lim, Hong Sun and Control Donolo, Marcos Angel Design and Control of a Ropeless Patcha, Animesh Committee Chair: Kachroo, P. A Continuum Approach to Power Elevator with Linear Switched Network Anomaly Detection with In- System Simulation Reluctance Motor Drive Actuation complete Audit Data Anderson, Christopher Robert Committee Chair: Centeno, V. Systems Committee Chair: Park, J. M. A Software Defined Ultra Wideband Committee Chair: Ramu, K. Transceiver Testbed for Communi- Edmison, Joshua Nathaniel Patel, Hiren Dhanji cations, Ranging, or Imaging Hardware Architectures for Soft- Louganski, Konstantin Ingredients for Successful System Committee Chair: Reed, J. H. ware Security Pavlovic Level Automation & Design Committee Chair: Jones, M. T. Generalized Average-Current-Mode Methodology Atcitty, Stanley Control of Single-Phase AC-DC Committee Chair: Shukla, S. K. Electrochemical Charac- Gadre, Aditya Boost Converters with Power Factor terization for Electric Utility Observability Analysis in Navigation Correction Refaei, Mohamed Tamer A. Applications Systems with an Underwater Committee Chair: Lai, J. Adaptation in Reputation Manage- Committee Chair: Liu, Y. Vehicle Application ment Systems for Ad hoc Networks Bhaduri, Debayan Committee Chair: Stilwell, D. J. Lu, Bing Committee Chair: DaSilva, L. A. Design and Analysis of Defect- and Investigation of High-Density Inte- Fault-Tolerant Nano-Computing Ibrahim, Jihad El Sayeed grated Solution for AC/DC Conver- Schoenig, Gregory Neumann Systems Abdal sion of a Distributed Power System Contributions to Robust Adaptive Committee Chair: Shukla, S.K. Algorithms and Architectures for Committee Chair: Lee, F. C. Signal Processing with Application UWB Receiver Design to Space-Time Adaptive Radar Mellodge, Patricia Ann Chembil-Palat, Ramesh Committee Chair: Buehrer, R. M. Committee Chair: Mili, L. M. Model Abstraction in Dynamical Performance Analysis of Coopera- Systems: Application to Mobile tive Communication for Wireless Ikuma, Takeshi Shen, Fabin Robot Control Networks Non-Wiener Effects in Narrowband UV-Induced Intrinsic Fabry-Perot Committee Chair: Kachroo, P. Committee Chair: Reed, J. H. Interference Mitigation Using Interferometric Fiber Sensors and Adaptive Transversal Equalizers Their for Quasi-Distrib- Menon, Rekha Chen, Xiaoding Committee Chair: Beex, A. A. uted Temperature and Strain Interference Avoidance based Exploring Temporal and Spatial Sensing Underlay Techniques for Dynamic Correlations on Circuit Variables for Kim, Jong-Han Committee Chair: Wang, A. Spectrum Sharing Enhancing Simulation-Based Test On the Impact of MIMO Implemen- Committee Chair: Buehrer, R. M. & Generation tations on Cellular Networks: An Shen, Wei Reed, J. H. Committee Chair: Hsiao, M. S. Analytical Approach from a Design of High-Density Transform- Systems Perspective ers for High-Frequency High-Power Chen, Xiaopei Mo, Tianmin Committee Chair: Reed, J. H. Converters Ultra-Narrow Laser Linewidth Throughput Optimization and Trans- Committee Chair: Boroyevich, D. & Measurement mitter Power Saving (TOTPS) Kompella, Sastry Venkata Wang, F. Committee Chair: Wang, A. Algorithm and Extended TOTPS Video Communications over (ETOTPS) Algorithm for IEEE Dynamic Ad Hoc Networks Thompson, Michael Stewart Cho, Hyeonjoong 802.11 Links Committee Chair: Hou, Y. T. Service Discovery in Pervasive Utility Accrual Real-Time Schedul- Committee Chair: Bostian, C.W. ing and Synchronization on Single Computing Environments Kook, Kyung Soo Committee Chair: Midkiff, S. F. and Multiprocessors: Models, Algo- Mohammad, Maruf Hossain Simulation Studies on Novel Find- rithms, and Tradeoffs Cellular Diagnostic Systems Using ings in Power Systems Venkatesh, Swaroop Committee Chair: Ravindran, B. Hidden Markov Models Committee Chair: Liu, Y. The Design and Modeling of Ultra- Committee Chair: Tranter, W. H. Clark, Jeffrey Robert Wideband Position-Location Net- Double Negative Metamaterials Koujah, Fahad works Nayfeh, Nader Ali in Dielectric Waveguide Configura- A Power-Aware Routing Scheme for Committee Chair: Buehrer,R. M. Local and Global Stability and tions Ad Hoc Networks Dynamics of a Class of Nonlinear Committee Chair: Safaai-Jazi, A. Committee Chair: Midkiff, S. F. Vimjam, Vishnu Chaithanya Time-Delayed One-Degree-of-Free- Strategies for SAT-Based Formal dom Systems Verification Committee Chair: Baumann, W. T. Committee Chair: Hsiao, M. S.

42 Wadoo, Sabiha Amin In addition to his responsibility for system architecture, learning functions, and core AI abilities, Evacuation Distributed Feedback Rondeau was known as “The Philospher” on Charles Bostian’s cognitive radio team. Control and Abstraction Committee Chair: Kachroo, P. Wang, Hongfang Rondeau wins best dissertation Investigation of Power Semiconduc- tor Devices for High Frequency High Density Power Converters for cognitive radio work Committee Chair: Wang, F. homas Rondeau (BSEE ’03, MSEE ’06, Ph.D. ’07) has been awarded the Virginia Tech 2007 Out- Wang, Xingwei standing Dissertation Award for Sciences and Engineering for his dissertation, Application of Artifi- Label-free DNA Sequence Detec- tion Using Oligonucleotide Func- Tcial Intelligence to Wireless Communications. tionalized Fiber Probe with a The Graduate School gives only two such awards each year; one in sciences and engineering, the Miniature Protrusion other in humanities and social sciences. The awards are based on originality of the idea, contributions Committee Chair: Wang, A. to the field, presentation of the ideas, and the quality of writing. Each department may nominate one Wang, Zhuang dissertation per year for the award. Intrinsic Fabry-Perot Interferomet- ric Fiber Sensor Based on Ultra- Rondeau’s dissertation describes the theory, design, and implementation of a cognitive radio engine, Short Bragg Gratings for the enabling technology of cognitive radio. “A cognitive radio,” he writes, “is a wireless communica- Quasi-Distributed Strain and Tem- tions device capable of sensing the environment and making decisions on how to use the available radio perature Measurements resources to enable communica- Committee Chair: Wang, A. tions with a certain quality of On a visit to service. The cognitive engine, Wood, Kerry Neil the U.S. in Directional Communications to Im- the intelligent system behind the prove Multicast Lifetime in Ad Hoc cognitive radio, combines sens- November, Networks ing, learning, and optimization Committee Chair: DaSilva, L. A. algorithms to control and adapt Tom Rondeau Xiao, Chucheng the radio system from the physi- An Investigation of Fundamental stopped Frequency Limitations for HF/VHF cal layer and up the communica- Power Conversion tion stack.” to capture Committee Chair: Odendaal, H. His cognitive engine plat- network data Zhang, Li form should allow easy develop- Study of FACTS/ESS Applications in ment of new components and outside the Bulk Power System algorithms for the application, Committee Chair: Liu, Y. MANIAC he says. Zhao, Youping Rondeau became involved Challenge Enabling Cognitive Radios through in ECE’s wireless communica- Radio Environment Maps competition. Committee Chair: Reed, J. H. tions research while a sophomore and has been involved in cogni- When com- Zhu, Dan Electric Distribution Reliability tive radio development almost piled, the data Analysis Considering Time-Varying since its inception. His work has Load, Weather Conditions and led to several patents in the tech- Reconfiguration with Distributed will be avail- Generation nology. He currently holds a Committee Chair: Broadwater,R. P. post-doctoral position with able on the CTVR at Trinity College Dub- CTVR website. lin, Ireland.

43 Honors & Awards James Thorp and Arun Amy Bell was named a Univer- Phadke were honored with the sity Scholar-in-Residence for HONORS & 2008 Benjamin Franklin Medal the American Association of in Electrical Engineering for University Women Education their combined contributions Foundation. ACHIEVEMENTS in strengthening the immunity of the power grid to blackouts. Joseph Tront was awarded an Phadke also was awarded the 2007 Laureate Award in the International & HKN 2007 Vladimir Karapetoff Computerworld Honors Pro- Award, along with Stanley gram for his work in tablet PC- National Service Horowitz, for their technical based learning environments. contributions to the field of Bob Clauer is member of the Agency Microsystems Technol- power system protection and Sandeep Shukla was honored Polar Research Board of the ogy Office (DARPA/MTO). control. by the State University of New National Academy of Sciences York with a Distinguished and also in that capacity is a T.-C. Poon has been ap- G.Q. Lu’s development of nan- Alumni Award in Science & member of the U.S. National pointed an adjunct professor oTach was listed one of the Technology. Committee for the Interna- by the National Central Univer- 100 most technologically sig- tional Polar Year, which is com- sity in Taiwan. nificant products of 2007 by Student teams from Wire- memorating the 50th R&D Magazine. less@VT won top honors at anniversary of the Interna- Saifur Rahman was elected the Software Defined Radio tional Geophysical Year. Vice President for New Initia- Masoud Agah received an Forum’s 2007 Smart Radio tives of the IEEE Power and NSF CAREER award for “GC Design Challenge. The team Scott Midkiff is serving as Energy Society for 2008-2009. Matrix, a Microsystem Ap- advised by Charles Bostian program director of the Electri- proach for Complex Gas won the overall grand prize cal, Communications and Amir Zaghloul was elected to Analysis.” and the team advised by Carl Cyber Systems (ECCS) pro- the Board of the Applied Com- Dietrich and Jeff Reed won the gram in the Directorate for En- putational Electromagnetics Jung-Min Park received an Best Design Award. gineering of the National Society for a three-year term. NSF CAREER award for “Non- Science Foundation. He is Conventional Solutions for Charles Bostian was selected also serving as a member of Amy Bell served as chair of Ensuring Security in Cognitive as Virginia Tech’s 2008 Out- the Joint Tactical Radio Sys- the IEEE Educational Activities Radio Networks.” standing Dissertation Advisor tem (JTRS) Network Enterprise Board, Public Awareness Com- in the Engineering and Sci- Domain (NED) Defense Sup- mittee. She was also the Michael Hsiao’s paper was ence category as the advisor port Review team for the Di- founder and director of the designated one of the most in- of Thomas Rondeau. rector, Defense Research and Board’s Real World Engineer- fluential of 10 years (1998- Engineering in the Office of ing Projects Program, 2007. 2007) at the Design Thomas Rondeau received the the Secretary of Defense. Automation and Test in Europe 2008 Virginia Tech Outstand- Yue (Joseph) Wang is serving (DATE) Conference, 2008. ing Dissertation Award. Sanjay Raman is serving as as an external reviewer for the Program Manager, Defense Ad- Food and Drug Research Pro- Krishnan Ramu was the Patrick Schaumont won an vanced Research Programs grams. keynote speaker at the POW- Outstanding new Assistant ERENG 2007 conference and Professor Award in the College Books Published spoke on “Switched reluc- of Engineering. tance motor drives: past, pres- T.-C. Poon pub- 2008, and PSpice for Basic ent, and future.” A paper he Sanjay Raman was named a lished Optical Circuit Analysis, Second Edi- co-authored received a first College of Engineering Faculty Scanning Hologra- tion, McGraw-Hill Higher Edu- prize award from the IEEE In- Fellow. phy with MATLAB, cation, 2007. dustry Applications Society’s Springer, 2007. Industrial Drives Committee. Joseph Tront pub- lished PSpice for Dong Ha was named a Fellow Basic Microelectronics, Mc- of the IEEE for leadership in Graw-Hill Higher Education, VLSI design and test.

44 Conference Chairs Editorships Mohamed Eltoweissy is Thomas Hou co-chaired the T.-C. Poon served as founding Amy Bell served as associate serving as co-chair for the NSF Workshop on Bridge the chair of the 2007 Optical Soci- editor of IEEE Signal Processing 2nd IEEE Workshop on Mis- Gap Between Wireless Net- ety of America (OSA) topical Magazine. sion Critical Networks, April working Technologies and Ad- meeting “Digital Holography Tamal Bose is associate editor 2008. His is also workshops vances at the Physical Layer, and 3-D Imaging,” June 2007. of Research Letters in Signal co-chair for INFOCOM 2008. August 2007. He also co- He also served as chair of the Processing, and IEICE Transac- chaired the Technical Program 2008 meeting, March 2008. tions on Fundamentals of Elec- Sandeep Shukla was program Committee at the Second In- tronics, Communications and co-chair for the 7th Interna- ternational Conference on Dong Ha served as sympsium Computer Sciences. tional Conference on Applica- Cognitive Radio Oriented Wire- chair for the Communication tions of Concurrency for less Networks and Communi- and Networking Technology Thomas Hou is editor of IEEE System Design, June 2007. cations (CROWNCOM), July, Symposium, August 2007. Transactions on Wireless Com- 2007. munications, ACM/Springer Wireless Networks (WINET), and Elsevier Ad Hoc Networks Journal.

Patents Awarded Michael Hsiao is on the edito- “Adaptive Bus Voltage Position- “Intrinsic Fabry-Perot Optical “Multiphase Voltage Regulator rial board of IEEE Design & Test ing for Two-Stage Voltage Reg- Fiber Sensors and Their Multi- Having Coupled Inductors with of Computers, the Journal of ulators,” J. Wei, M. Xu, F.C. pliexing,” A. Wang. Reduced Winding Resistance,” Electronic Testing: Theory and Lee. J. Zhou, F.C. Lee, M. Xu, Y. “LTCC-Based Modular MEMS Dong. Applications, and the Journal of “Buck Converter with High Effi- Phased Array,” A. Zaghloul. Embedded Computing. He was ciency Gate Driver Providing “ Sensors for guest editor of ACM Transac- Extremely Short Dead Time,” “Method and Apparatus for a Harsh Environments,” tions on Design Automation of Y. Ren, F.C. Lee. Bandwidth Broker in a Packet A. Wang, J. Xu. Electronic Systems for the Janu- Network,” Z.-L. Zhang, Y.T. ary 2008 issue. “Cognitive Radio Engine Based Hou, Z. Duan. “Power Converters Having Ca- on Genetic Algorithms in a pacitor Resonant with Trans- T.-C. Poon is associate editor Network,” C.W. Bostian, W.R. “Method and Apparatus for former Leakage Inductance,” of International Journal of Opto- Cyre, T.M. Gallagher, C.J. Control and Routing of Wire- Y. Ren, F.C. Lee, M. Xu. mechatronics and of Applied Rieser, T.W. Rondeau. less Sensor Networks,” Y.T. Optics. He is also feature edi- Hou, S. Mao. “Power Converters Having Out- tor of the Applied Optics issue “Current Sensing in Multiple put Capacitor Resonant with on Digital Holo graphy and 3-D Coupled Industors by Time “Method and Apparatus for Autotransformer Leakage In- Imaging. Constant Matching to Leakage Packet Scheduling Using Vir- ductance,” Y. Ren, J. Sun, M. Inductance,” Y. Dong, M. Xu, tual Time Stamp for High Ca- Xu, F.C. Lee. Sanjay Raman is associate F.C. Lee. pacity Combined Input and editor of IEEE Transactions Output Queued Switching Sys- “Real-Time Software Receiver,” of Microwave Theory and “Decision Selection and Asso- tem,” Z.-L. Zhang, Y.T. Hou. B. Ledvina. Techniques. ciated Learning for Computing All Solutions in Automatic Test “Method and System for Gen- “Self-Driven Scheme for Syn- Sandeep Shukla is associate Pattern Generation (ATPG) and erating a Bitstream View of a chronous Rectifier having No editor for IEEE Design & Test, Satisfiability,” M.S. Hsiao, K. Design,” C.D. Patterson. Body Diode,” M. Xu, J. Sun, J. and IEEE Transactions on Indus- Chandrasekar. Zhou, F.C. Lee. trial Informatics. He guest ed- “Methods of Estimating Sus- ited the Globally Asynchronous “Device and Method for Tuning ceptibility to Single Event Up- “Stub Loaded Helix Antenna,” and Locally Synchronous De- an SPR Device,” K. Meehan, sets for a Design Implemented R.M. Barts, W.L. Stutzman. sign” special issue of IEEE R.E.Dessy. in an FPGA,” C.D. Patterson. Design & Test and the special “Topologies for Using Multiple issue on “Programming Models “EMI Filter and Frequency Fil- “Multichannel Adaptive Filter Energy Sources for Power Con- and Architectures for Embed- ters Having Capacitor with In- for Noise and/or Interference versions,” J.S. Lai. ded Systems” of IEEE Transac- ductance Cancellation Loop,” Cancellation,” A.A. Beex, J.R. tions of Computers. S. Wang, F.C. Lee, W.G. Oden- Zeidler. “Wideband Modular MEMS daal. Phased Array,” A. Zaghloul, O. Daniel Stilwell is associate Kilic. editor IEEEJournal of Oceanic “Infinite Impulse Response Engineering. Multiplierless Digital Filter Ar- chitecture,” T. Bose. 45 DONORS TO ECE During the Fiscal Year 2007 Alumni who contributed to ECE Harold W., Jr., &. June P. Adams Michael S. & Karen G. Fulk John K. Loftis, Jr. James F. Schooler Glenn M. Allen Benjamin M. Grady Samarina Lowrie Hugh D. Scott Donald W. Armistead Michele U. & Mark J. Yujie I. Lu & Xing Wu Stephen V. Smith Brian D. Bailey Greenwood Kevin S. & Leslie J. Mastropaolo David W. & Dorothy Snodgrass William D. Barnhart James T. Griffin James C. Mills Gary L. & Julia G. Spadin Andrew Beach Jeffrey G. Hadley Christopher & Michelle M. Munk Bill L. Stackhouse Thomas G. & Lisa S. Beazell Paul S. Hamer Carl G. & Christine M. Murphy Charles W. Stewart, Jr. T. Wayne Belvin James M. Hannett Stewart L. & Mary L. Ocheltree Eric B. Stogoski Nancy B. & Leland S. Kenneth C. & Dorothy J. Harris Stewart L., Jr. & Sharon L. Douglas A. Teeter Bloebaum Michael G. Heavener Ocheltree Matthew K. & Jennifer S. Thomas William J. Boyer David E. Helinski Jeffrey T. Olson William L. & Elizabeth C. Robert F. Bruce Kurt M. Hinds Lowell T. Overby Thompson Charles M. Cacioppo Hsien L. &. Hui-Lein P. Huang Don M. & Dorla S. Powers C. Hyde & Gloria J. Tucker Kathleen M. & David L. Conway George E. Hudson George S. Powley Steven P. Turner Doyle C. Counts Daniel S. &. Renee R. Jarrett Craig L. Purdy James A. & Carla V. Wilding William C. Decker, Jr. Kenneth L. Johnson Stafford M. Query, Jr. Chane R. Williamson Vincent R. & Rose M. DiLosa Maryann W. & Joseph E. Michael J. & Virginia K. Ratway Richard A. & Amy E. Woynicz Steve O. Dixon Kusterer William G. & Jacqueline S.Roberts Richard F. Wrenn Grant A. & Margaret B.Dove William K. Lamp Carlos V. & Linda Roberts Theodore G. & Acquilla A. Warren D. Drumheller Patricia & John W. Lane Daniel M. & Pamela Sable Wyatt Kevin W. Filano Joseph C. Liberti, Jr. Karl D. Salnoske Robert W. Freund James B. Loftin, III William C. Sanger ECE Friends who contributed to ECE Anne Barber James A.& Kathleen M. Eder David M. & Luwanna S. Lofe John Seelke Frederick Barney James Goodrich Jeanne C. & James E. Melone, Sr. Richard Sergel Donald Benjamin Frederick Gorbet Michael L. Miles David Taylor Kenneth Berger Debra Hilt Julie Morgan Thomas Vandervort Richard Byrne Stanley Honda Mitchell Needham David Whiteley Joseph Conner Joanne Joe David Nevius Robert Cummings Stanley Johnson Kenneth Peterson Richard Drouin Mark Laiby Richard Schneider

Corporate Donors ABB, Inc. Jarrett Electric Company Inc. Raytheon Company Accenture Foundation Inc. John Wiley & Sons Inc. Reed Engineering Air Products & Chemicals, Inc. Lockheed Martin Corporation RF Micro Devices Inc. AK Steel Foundation Long Consulting RFMD American Electric Power Service Corp. Manitoba Hydro Samsung Electronics Company Ltd. Appalachian Power Company Micron Technology Inc. SANS Institute Boeing Matching Gift Company Micron Technology Foundation, Inc. Schering-Plough Foundation, Inc. ChevronTexaco Matching Gift Program Microsoft Corporation Science Applications International Corp. Comcast Cable Midwest Reliability Organization Scholarship Foundation- Danaher Motion MISO Lockheed Martin Matching Gifts Dominion Foundation Network & Securities Technologies, Inc. Tektronix, Inc. Electrical Distribution Design Inc. North American Electric Tyco Electronics Corporation GE Foundation Northeast Utilities Verizon Foundation IBM International Foundation Northrop Grumman Foundation Wachovia Foundation, Inc. Intel Corporation Radio Club of America, Inc.

46 Corporate and Industrial Affiliates CPES Partners Principal Members Plus Intel Corporation Honda Motor Co., Ltd. Wireless @VT ABB, Inc. – Corporate Research Johnson Controls International Corp. Analog Devices KEMA, Inc. Ingersoll-Rand Company Applied Signal Technology, Inc. The Boeing Company L-3 Communications, Powe JRI Solutions, Ltd. Army Research Office Crane Aerospace Paragon Inc. KEMET Corporation Digital Receiver Technology Inc. & Electronics Microsoft Corporation Kohler Company DRS Technologies Delta Electronics NetPower Technologies, Inc. LEM USA, Inc. Inc. FSP Group, Inc. Nippon Chemi-Con Corp. Magnetek, Inc. Raytheon IIS GE Global Research Northrop Grumman Miller Electric Mfg. Co. Rockwell Collins Hipro Electronics Co., Ltd. OSRAM SYLVANIA, Inc. Milwaukee Electric Samsung Telecommunications Infineon Technologies Panasonic Electric Works Lab- Tool Company America International Rectifier oratory of America, Inc. MPC Products Corporation Sharp Labs of America Intersil Corporation Schneider Toshiba MTS Systems Corporation Syracuse Research Corp. Linear Technology Inverter Europe Nissan Motor Co., Ltd. Lite-On Technology Corporation Semikron International GmbH Oak Ridge National Laboratory Thales Communications MKS Instruments, Inc. Shindengen Electric Oshkosh Truck Corporation Tyco Electronics Murata Power Solutions Mfg. Co., Ltd. Otis Elevator Company National Corp. Toyota Motor Corporation Pacific Scientific EKD NXP Phoenix International Space@VT Primarion Corpporation Affiliate Members Plexim GmbH Affiliates Renesas Technology Corp. ABB Inc., Drives & Power Regal Beloit Orbital Sciences Corporation Richtek Technology Corp. Products Div. Remy, Inc. Northrop Grumman Corp. Rolls-Royce Ansoft Corporation Samsung Electric Co., Ltd. VPT Incorporated Texas Instruments AO Smith Corporation Sauer Danfoss Astronics S&C Electric Company Principal Members Baldor/Dodge/Reliance Schneider Electric - Square D DRS Power and Control (Rockwell Automation) TECO Westinghouse Technologies, Inc. Caterpillar, Inc. Toshiba International Corp. Eltek Valere Continental Automotive Trane Company Emerson Network Systems Transim Technology Power Co., Ltd Cree, Inc. Unico, Inc. Groupe SAFRAN Curtis Instruments United Technologies HR Textron, Textron Danfoss Drives Research Center Systems Corporation Denver Thomas Garnder VPT, Inc. Maxim Integrated Products Eaton Corporation – Whirlpool Corporation Rockwell Automation - Innovation Center Yaskawa Electric America, Inc. Allen-Bradley Electronic Concepts, Inc. SEW EURODRIVE Emerson Electric Company GmbH & Co. KG Ford Motor Company Vacon, Inc. Fuji Electric Advanced Although every effort has been made to Technology Co., Ltd. ensure the accuracy of this report, we ac- Associate Members GE Energy knowledge that errors may have occurred. If BAE Systems, Inc. GM Advanced Technology your name was omitted or listed incorrectly, Crown International Center please accept our sincere apologies and Grundfos A/S Densei-Lambda KK send corrections to the Office of University Hamilton Sundstrand Hitachi Computer Development at 540/231-2801. Peripherals Co., Ltd. Hoganas AB

47 ECE FACULTY A. Lynn Abbott Claudio da Silva Pushkin Kachroo Hardus Odendaal Associate Professor Assistant Professor Associate Professor Associate Professor Illinois ’89 University of California UC Berkeley ’93 Rand Afrikaans ’97 Masoud Agah San Diego ’05 Jason Lai Marius Orlowski Assistant Professor Luiz DaSilva Professor Professor, VMEC Chair Michigan ’05 Associate Professor Tennessee ’89 Tuebingen ’81 Peter Athanas Kansas ’98 Brent Ledvina Jung-Min Park Professor William A. Davis Assistant Professor Assistant Professor Brown ’92 Professor Cornell ’03 Purdue ’03 Scott Bailey Illinois ’74 Fred C. Lee Cameron Patterson Assistant Professor Jaime de la Ree University Distinguished Associate Professor Colorado ’95 Associate Professor & Assis- Professor; Duke ’74 Calgary ’92 William T. Baumann tant Department Head Douglas Lindner JoAnn Paul Associate Professor Pittsburgh ’84 Associate Professor Associate Professor Johns Hopkins ’85 Steven Ellingson Illinois ’82 Pittsburgh ’94 A. A. (Louis) Beex Assistant Professor Yilu Liu Paul Plassmann Professor Ohio State ’00 Professor Professor Colorado State ’79 Mohamed Eltoweissy Ohio State ’89 Cornell ’90 Amy E. Bell Associate Professor G. Q. Lu T.C. Poon Associate Professor Old Dominion ’93 Professor Professor Michigan ’97 Louis Guido Harvard ’90 Iowa ’82 Dushan Boroyevich Associate Professor Allen MacKenzie Timothy Pratt American Electric Power Illinois ’89 Assistant Professor Professor Professor; Virginia Tech ’86 Dong S. Ha Cornell ’03 Birmingham ’68 Tamal Bose Professor Majid Manteghi Saifur Rahman Professor Iowa ’86 Assistant Professor Joseph Loring Professor Southern Illinois ’88 Robert Hendricks UCLA ’05 Virginia Tech ’78 Charles W. Bostian Professor Tom Martin Sanjay Raman Alumni Distinguished Cornell ’64 Associate Professor Associate Professor Professor; NC State ’67 Thomas Hou Carnegie Mellon ’99 Michigan ’97 Robert P. Broadwater Associate Professor Kathleen Meehan Krishnan Ramu Professor Polytechnic Univ. ’98 Assistant Professor Professor Virginia Tech ’77 Michael Hsiao Illinois ’85 Concordia ’82 Gary S. Brown Professor Scott F. Midkiff Binoy Ravindran Bradley Distinguished Illinois ’97 Professor Associate Professor Professor of Electromagnetics, Chao Huang Duke ’85 UT Arlington ’98 Illinois ’67 Assistant Professor Lamine Mili Jeffrey H. Reed Michael Buehrer Princeton ’05 Professor Willis G. Worcester Professor Associate Professor Ira Jacobs Liege ’87 UC Davis ’87 Virginia Tech ’96 Professor Leyla Nazhandali Sedki Riad Virgilio Centeno Purdue ’55 Assistant Professor Professor Associate Professor Mark Jones Michigan ’06 Toledo ’76 Virginia Tech ’95 Associate Professor Khai D.T. Ngo Ahmad Safaai-Jazi C. Robert Clauer Duke ’90 Professor Professor Professor Caltech ’84 McGill ’78 UCLA ’80

48 ECE INDUSTRIAL ADVISORY BOARD Wayne Scales Jason Xuan Miroslav Begovic ’89 Dave Marsell ’88 Professor Associate Professor Professor Vice President of Engineering Cornell ’88 Maryland ’97 School of Electrical and Pressure Systems, Inc. Patrick Schaumont Yaling Yang Computer Engineering Jeannette Mills ’88 Assistant Professor Assistant Professor Georgia Institute of Technology Senior Vice President UCLA ’04 Illinois ’06 Rick Brisbin Gas Business Operations Sandeep Shukla Amir Zaghloul Vice President & Planning Associate Professor Professor Southeast Region Baltimore Gas and Electric SUNY Albany ’97 Waterloo ’73 L-3 Communications Behnam Moradi Daniel Stilwell Titan Group Research Senior Member Associate Professor Christopher DeMarco of the Technical Staff Johns Hopkins ’99 Faculty Professor, Electrical and Micron Technology Kwa-Sur Tam & Instructors Computer Engineering Michael Newkirk ’88, ’90, ’94 Associate Professor Carl B. Dietrich University of Wisconsin- Principal Professional Staff Wisconsin ’85 Research Assistant Madison Johns Hopkins University James S. Thorp Professor Robert Fulton ’82 Applied Physics Laboratory Department Head Leslie K. Pendleton Vice President Hugh P. and Ethel C. Kelly Lew Roufberg ’87 Instructor Business Development Professor; Cornell ’62 Supervisor, Spacecraft Power Arun G. Phadke Space Systems Group Electronics William H. Tranter University Distinguished Orbital Sciences Corp. Johns Hopkins University Bradley Professor of Professor Emeritus Electrical Engineering & Truls Henriksen ’90 Applied Physics Laboratory Assistant Department Head Gerald Reid Consultant, Ecto, LLC Dan Sable ’85, ’91 Instructor Alabama ’70 Mike Hurley Advisory Board Chair, Joseph G. Tront Warren L. Stutzman Program Manager President and CEO Professor Thomas Phillips Professor Satellite Programs VPT, Inc. (Emeritus) SUNY Buffalo ’78 Naval Research Laboratory Dennis Sweeney ’86, ’92 Anbo Wang Jason Thweatt Stephen Larson ’90 Engineering Specialist Instructor Clayton Ayre Professor Manager, St. Louis Area Aerospace Corporation Dalian ’89 Dan Weimer Schneider Electric C. Hyde Tucker ’56 Research Professor Fred Wang John Logrando Retired, President and CEO Associate Professor Director, Electrical Power Bell Atlantic International USC ’90 Systems Engineering Timothy Winter ’81 Yue (Joseph) Wang Lockheed Martin Director, Air and Missile Professor Space Systems Company Defense Department Maryland ’95 Michael Keeton ’71 Systems Development & Chris Wyatt Senior Program Director Technology Division Assistant Professor Orbital Science Corporation Northrop Grumman Wake Forest School of Corporation–Electronic Medicine ’02 Gino Manzo Director, Microelectronics Systems Sector Ming Xu Associate Professor Technology and Products Brandon Witcher ’01, ’03 Zhejiang; ’97 Manassas Site Executive Senior Member BAE Systems of the Technical Staff Yong Xu Sandia National Laboratory Assistant Professor Virginia Tech is an equal Caltech ’01 opportunity employer. The Bradley Department Non-Profit Org. U.S. Postage of Electrical & Computer Engineering PAID Virginia Polytechnic Institute and State University Blacksburg, VA 24060 302 Whittemore Hall Permit No. 28 Blacksburg, VA 24061

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