A 3D-printing based learning
Stefan Andrei, PhD Associate Professor and Chair
11/17/2016 Presentation, Lamar University, 2016 1 Summary
Innovative ways to learn and teach 3D Printing technologies Designing 3D artifacts for learning and teaching Engaging students, staff, and instructors in the 3D- printing based learning and teaching at Lamar University
11/17/2016 Presentation, Lamar University, 2016 2 Innovative ways to learn and teach
The collaborative way of learning, where children sit around a table to work out a problem together (http://www.bbcactive.com/BBCActiveIdeasandResources/Innov ativeteachingmethodsvsthetraditionaluni.aspx). The use of educational video during lectures, which has transformed the engagement levels of students and has created a greatly enhanced learning experience (http://www.bbcactivevideoforlearning.com/). Tom Drummond, University of North Carolina at Charlotte, compiled a list of 12 best practices for learning and teaching concepts (http://teaching.uncc.edu/learning-resources/articles- books/best-practice/instructional-methods/best-practices- summary)
11/17/2016 Presentation, Lamar University, 2016 3 Drummond’s 12 best practices
1. Lecture Practices: effective ways to present new information orally to fit differences in learning styles.
interaction with audience, questions, surveys, explanations, stories 2. Group Discussion Triggers: effective ways to present a common experience to engage a group in a discussion.
short readings, individual task review, case studies 3. Thoughtful Questions: effective ways to formulate questions that foster engagement and confidence.
descriptions, reflections, analogies, predictions, justifications 4. Reflective Responses to Learner Contributions: effective ways to establish mutually beneficial communication by reflective listening.
paraphrase, parallel personal comment
11/17/2016 Presentation, Lamar University, 2016 4 Drummond’s 12 best practices (cont’d) 5. Rewarding Learner Participation: effective ways to support learner actions with well-timed, encouraging positives.
avoid praise, description, narration, self-talk 6. Active Learning Strategies: effective ways to foster active, constructive participation.
construction spirals, rounds, brainstorm, writing in class, concept models, simulations/games, peer teaching, question pairs, examinations 7. Cooperative Group Assignments: ways to assign formal cooperative tasks.
5. team member teaching, team effectiveness design, poster sessions 8. Goals to Grades Connections: establish a logical agreement of goals and objectives, flowing to measures of performance, criteria, and grading.
grades are referenced to criteria, requirements are detailed in writing
11/17/2016 Presentation, Lamar University, 2016 5 Drummond’s 12 best practices (cont’d)
9. Modeling: represent openness, continuous learning, and trust.
openness to experience in the here and now, incorporation into oneself of the process of change 10. Double Loop Feedback: facilitating mutual awareness of how one learns to learn.
objective description of physical reality, culturally accepted meaning, judgments and personal reality 11. Climate Setting: regulate the physical and mental climate.
meet the learner's needs for physical comfort and accessibility, define negotiable and non-negotiable areas, clarify the instructor's role, and the learner's role as members of a learning community 12. Fostering Learner Self-Responsibility: allow learners to plan and evaluate much of their learning.
involve learners in mutual planning, involve learners in formulating their learning objectives 11/17/2016 Presentation, Lamar University, 2016 6 https://www.sculpteo.com/blog/2015/11/17/3d- printing-in-education-from-elearning-to-emaking/
Learning by making has a long established story in education, and thanks to 3D Printing this educational principle makes a real come-back (November, 2015). Introducing 3D Printing into classrooms changes both the way students learn and the way educators teach. Every professor using a 3D printer in the classroom or using a cloud 3D Printing Service has observed:
3D Printing is changing the relationship between students and teachers.
First because 3D Printing technology is new and evolving constantly in many manners.
There are a limited amount of experts in 3D Printing around the world and it’s difficult to be aware of every application of 3D printing that takes place.
3D Printing classes are more open to discussion and student contributions are an important factor of success.
11/17/2016 Presentation, Lamar University, 2016 7 11/17/2016 Presentation, Lamar University, 2016 8 Main idea of Additive Manufacturing
Additive Manufacturing (AM) is a term to describe a set of technologies that create 3D objects by adding layer-upon- layer of material, which can vary from technology to technology, e.g.:
plastic, liquid, metal, powder filaments, sheet of paper, etc. But the common feature for all Addictive Manufacturing is the:
usage of a computer together with a special 3D modeling software. So, first thing to start:
create a CAD sketch. Then:
AM device reads data from CAD file and builds a structure layer by layer from printing material.
11/17/2016 Presentation, Lamar University, 2016 9 Examples of 3D printers: http://3dprintingfromscratch.com/common/types- of-3d-printers-or-3d-printing-technologies-overview/
11/17/2016 Presentation, Lamar University, 2016 10 Types of input files 1. Standard Tessellation Language (STL) file. 2. Virtual Reality Modeling Language (VRML), a newer digital 3D file type that also includes color. 3. Additive Manufacturing File Format (.AMF) is a new XML-based open standard for 3D printing. 4. GCode - this file contains detailed instructions for a 3D printer to follow for each slice, such as the starting point for each layer and the "route" that the nozzle or print head will follow in laying down the material. 5. In addition, 3D printer manufacturers may have their own proprietary input file formats that contain instructions specific to the methodology for that make or model, and that are compatible only with that manufacturer's software.
Note. This does not create a barrier to printing with these machines, as the proprietary file format is generated from the user's own STL or VRML file.
11/17/2016 Presentation, Lamar University, 2016 11 Free 3D software
1. Google SketchUp 10. Wings 3D 2. 3DCrafter 11. FreeCAD 3. 3Dtin 12. GLC Player 4. Anim8or 13. LeoCAD 5. Art of Illusion 14. Netfabb Studio Basic 6. Blender 15. K-3D 7. BRL-CAD 16. OpenSCAD 8. Creo Elements/Direct - formerly 17. Tinkercad CoCreate 9. DrawPlus Starter Edition
11/17/2016 Presentation, Lamar University, 2016 12 3DS Max - High-end commercial 3D modeling tools
1. Alibre - One of the most 8. Maya affordable CAM programs. 9. Magics 2. AC3D 10. NetFabb 3. AutoCAD 11. Rhino3D 4. AutoQ3D 12. Solidworks 5. Cheetah3D 13. ZBrush 6. Cloud9 7. FormZ
11/17/2016 Presentation, Lamar University, 2016 13 Free STL software:
1. MeshLab:
Open source software for processing and editing of unstructured 3D triangular meshes.
It also has an extremely fast slide function. 2. Google SketchUp plugin:
A plugin script to import and export STL files for Google SketchUp.
Supports both binary and ASCII import and export. 3. STL-viewer:
Display and manipulate the contents of stereolithography or STL file. 4. Netfabb Studio:
A free Windows program for 3D printing to view, edit, analyze and repair STL files.
11/17/2016 Presentation, Lamar University, 2016 14 Google: context free grammar for "standard tessellation language" (STL)
11/17/2016 Presentation, Lamar University, 2016 15 The STL file structure (byte code – 7MB)
11/17/2016 Presentation, Lamar University, 2016 16 The STL file structure (text file – 1.3 MB)
11/17/2016 Presentation, Lamar University, 2016 17 The STL file structure (snippet of text representation)
solid OpenSCAD_Model facet normal 0 0 0 outer loop vertex -12.892 -0.886857 15.3505 vertex -12.8413 -1.22597 15.1614 vertex -13.2 -1.22597 15.1142 endloop endfacet . . . endsolid OpenSCAD_Model
11/17/2016 Presentation, Lamar University, 2016 18 The STL file structure (similar to reverse engineering)
The following Context-Free Grammar can generate the previous text (Open-Source Computer Assisted Design model):
1. S → solid OpenSCAD_Model Facets endsolid OpenSCAD_Model
2. Facets → Facet Facets | Facet 3. Facet → facet Position Origine OuterLoop endfacet 4. Position → normal | orthogonal
5. Origine → X_origine Y_origine Z_origine 6. X_origine → Number 7. Y_origine → Number 8. Z_origine → Number 9. OuterLoop → Vertex_A Vertex_B Vertex_C . . .
11/17/2016 Presentation, Lamar University, 2016 19 The STL file structure (reverse engineering)
. . . 10. Vertex_A → vertex A_coord B_coord C_coord 11. Vertex_B → vertex A_coord B_coord C_coord 12. Vertex_C → vertex A_coord B_coord C_coord
13. A_coord → Number 14. B_coord → Number 15. C_coord → Number 16. Number → IntegerPart . FractionalPart
17. IntegerPart → Digit | IntegerPart Digit 18. FractionalPart → Digit | Digit FractionalPart 19. Digit → 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
11/17/2016 Presentation, Lamar University, 2016 20 Is reverse engineering legal?
In the U.S., Section 103(f) of the Digital Millennium Copyright Act (DMCA) (17 USC § 1201 (f) - Reverse Engineering) specifically states that it is legal to reverse engineer and circumvent the protection to achieve interoperability between computer programs (such as information transfer between applications). Interoperability is defined in paragraph 4 of Section 103(f).
11/17/2016 Presentation, Lamar University, 2016 21 Popular 3D printers technologies
1. Stereolithography (SLA) 2. Fused Deposition Modeling (FDM) 3. Selective Laser Sintering (SLS) 4. Selective Laser Melting (SLM) 5. Electronic Beam Melting (EBM) 6. Laminated Object Manufacturing (LOM) 7. Bio Printers (recent technology)
11/17/2016 Presentation, Lamar University, 2016 22 1. Stereolithography (SLA)
This method was patented by Charles Hull, co-founder of 3D Systems, Inc., in 1986. He then set up 3D Systems Inc to commercialize his patent (www.3Dsystems.com). In fact, Japanese researcher Dr. Hideo Kodama first (1981) invented the modern layered approach to stereolithography by using ultraviolet light to cure photosensitive polymers. The process of printing involves a uniquely designed 3D printing machine called a stereolithograph apparatus (SLA), which converts liquid plastic into a solid 3D object (represented as a computer aid design (CAD) file, such as STL).
11/17/2016 Presentation, Lamar University, 2016 23 The SLA machine and its 3D generated object
11/17/2016 Presentation, Lamar University, 2016 24 2. Fused deposition modeling (FDM) Fused deposition modeling (FDM) technology was developed and implemented at first time by Scott Crump, Stratasys Ltd. founder, in 1987. Other 3D printing companies have adopted similar technologies but under different names. A well-known nowadays company MakerBot coined a nearly identical technology known as Fused Filament Fabrication (FFF). With the help of FDM you can print not only functional prototypes, but also concept models and final end-use products (resolution 1/20 per mm).
high-performance and engineering-grade thermoplastic,
very beneficial for mechanic engineers and manufactures.
the only 3D printing technology that builds parts with production-grade thermoplastics,
excellent mechanical, thermal and chemical qualities.
11/17/2016 Presentation, Lamar University, 2016 25 Similarity with SLA printing method
3D printing machines that use FDM Technology build objects layer by layer from the very bottom up by heating and extruding thermoplastic filament. FDM is a bit similar to stereolithography (SLA). Comparing to stereolithography, this technique is slower in processing, but with better resolution. When printing is completed, support materials can easily be removed either by placing an object into a water and detergent solution or snapping the support material off by hand.
11/17/2016 Presentation, Lamar University, 2016 26 Examples of FDM 3D-printed objects
11/17/2016 Presentation, Lamar University, 2016 27 Benefits to the society
FDM technology is widely spread nowadays in variety of industries such as:
automobile companies like Hyundai and BMW or
food companies like Nestle and Dial.
end-use products, particularly small, detailed parts and specialized manufacturing tools.
food, drug packaging, and the medical industry. FDM is used for new product development, model concept and prototyping and even in manufacturing development. The most common filaments are:
ABS (acrylonitrile butadiene styrene),
PC (polycarbonate) filaments,
PLA (polylactic acid) made out of corn.
11/17/2016 Presentation, Lamar University, 2016 28 Price ranges
The price for those 3D printers depends on size and model. Professional ones usually cost from $10,000 and more. 3D Printers designed for home use are not so expensive. There are several models like Replicator of MakerBot, Mojo of Stratasys and Cube of 3D Systems. The price for these models varies from $1,200 to $10,000. However, new start-ups offer more and more affordable versions of FDM 3D printers, the price of which can be just about $300-$400.
11/17/2016 Presentation, Lamar University, 2016 29 3. Selective Laser Sintering (SLS)
… is a technique that uses laser as power source to form solid 3D objects. This technique was developed by Carl Deckard, a student of Texas University, and his professor Joe Beaman in 1988. Later on they took part in foundation of Desk Top Manufacturing (DTM) Corp., that was sold to its big competitor 3D Systems in 2001. The main difference between SLS and SLA is that it uses powdered material in the vat instead of liquid resin as stereolithography does.
11/17/2016 Presentation, Lamar University, 2016 30 Comparison with SLA and FDM
Unlike some other additive manufacturing processes,
such as stereolithography (SLA) and fused deposition modeling (FDM), SLS does not need to use any support structures as the object being printed is constantly surrounded by unsintered powder.
11/17/2016 Presentation, Lamar University, 2016 31 Example of an SLS 3D printed object
11/17/2016 Presentation, Lamar University, 2016 32 Materials and prices used by SLS
Like all other methods listed above the process starts with creation of computer-aided design (CAD) file, which then needs to be converted to .stl format by special software.
The material to print with might be anything from nylon, ceramics and glass to some metals like aluminum, steel or silver. Due to wide variety of materials that can be used with this type of 3D printer the SLS technology is very popular for 3D printing customized products. SLS is more spread among manufactures rather than 3D amateurs at home as this technology requires the use of high- powered lasers, which makes the printer to be very expensive.
11/17/2016 Presentation, Lamar University, 2016 33 4. Selective laser melting (SLM)
… is a technique that also uses 3D CAD data as a source and forms 3D object by means of a high-power laser beam that fuses and melts metallic powders together. In many sources SLM is considered to be a subcategory of selective laser sintering (SLS). But this is not so true as SLM process fully melts the metal material into solid 3D-dimentional part unlike selective laser sintering. The history of SLM started with German research project held by group of Fraunhofer-Institut für LaserTechnik in 1995.
11/17/2016 Presentation, Lamar University, 2016 34 The main design of SLM
11/17/2016 Presentation, Lamar University, 2016 35 Example of an SLM 3D printing object
11/17/2016 Presentation, Lamar University, 2016 36 The main idea of SLM printing
The fine metal powder is evenly distributed onto a plate, then each slice of 2D layer image is intensively fused by applying high laser energy that is directed to the powdered plate. The energy of laser is so intense that metal powder melts fully and forms a solid object. After the layer is completed the process starts over again for the next layer. Metals that can be used for SLM include stainless steel, titanium, cobalt chrome and aluminum.
11/17/2016 Presentation, Lamar University, 2016 37 Applications
1. parts with complex geometries and structures with thin walls and hidden voids or channels. 2. aerospace application for different lightweight parts. 3. tooling and physical access difficulties to surfaces for machining, as well as restrict the design of components. 4. manufactures of aerospace and medical orthopedics.
11/17/2016 Presentation, Lamar University, 2016 38 5. Electronic Beam Melting (EBM)
EBM is another type of additive manufacturing for metal parts. It was originally coined by Arcam AB Inc. in 2001. The same as SLM, this 3D printing method is a powder bed fusion technique. While SLM uses high-power laser beam as its power source, EBM uses an electron beam instead, which is the main difference between these two methods. The rest of the processes is pretty similar.
11/17/2016 Presentation, Lamar University, 2016 39 The main idea of EBM 3D printing
The material used in EBM is metal powder that melts and forms a 3D part layer by layer by means of a computer, that controls electron beam in high vacuum. Contrary to SLS, EBM goes for full melting of the metal powder. The process is usually conducted under high temperature up to 1000 °C.
11/17/2016 Presentation, Lamar University, 2016 40 Prices and applications
Comparing to SLM the process of EBM is rather slow and expensive, also the availability of materials is limited. So the method is not so popular though still used in some of manufacturing processes. Currently the most well spread materials that are used for EBM are commercially pure Titanium, Inconel 718 and Inconel 625. The application of EBM is mainly focused on medical implants and aerospace area.
11/17/2016 Presentation, Lamar University, 2016 41 6. Laminated object manufacturing (LOM)
… is one more rapid prototyping system that was developed by the California-based company Helisys Inc. in 2013. During the LOM process, layers of adhesive-coated paper, plastic or metal laminates are fused together using heat and pressure and then cut to shape with a computer controlled laser or knife. Post-processing of 3D printed parts includes such steps as machining and drilling.
11/17/2016 Presentation, Lamar University, 2016 42 The main steps of LOM 3D printing
The LOM process includes several steps. Firstly, CAD file is transformed to computer format, which are usually STL or 3DS. LOM printers use continuous sheet coated with an adhesive, which is laid down across substrate with a heated roller. The heated roller that is passed over the material sheet on substrate melts its adhesive. Then laser or knife traces desired dimensions of the part. Also the laser crosses hatches of any excess material in order to help to remove it easily after the printing is done.
11/17/2016 Presentation, Lamar University, 2016 43 Prices and speed of LOM
Probably LOM is not the most popular 3D printing method but one of the most affordable and fastest. The cost of printing is low due to not expensive raw materials. Objects printed with LOM can be relatively big, that means that no chemical reaction needed to print large parts.
11/17/2016 Presentation, Lamar University, 2016 44 A LOM 3D printed object
11/17/2016 Presentation, Lamar University, 2016 45 LOM Vendors
Currently Cubic Technologies, the successor to Helisys Inc., is the main manufacturer of LOM printers. There are not too many companies these days that work with LOM technology. Additional vendor: the Irish company Mcor Technologies Ltd. sells LOM 3D printers.
Their devices are widely being used by artists, architects and product developers to create affordable projects from usual letter paper. The printers that are being sold by Cubic Technologies for home use are pretty expensive comparing to Makerbot Replicator or 3D System’s Cube devices.
11/17/2016 Presentation, Lamar University, 2016 46 7. BioPrinting … is the process of creating cell patterns in a confined space using 3D printing technologies. Applications:
to print tissues and organs to help research drugs and pills
to incorporate the printing of scaffolds for regenerating joints and ligaments Organovo (San Diego, 2007): designs and develops functional, three dimensional human tissue with NovoGen MMX Bioprinter (www.organovo.com)
The living test tissues provide researchers the opportunity to test drugs before administering the drug to a living person. Inkredible (Sweden, 2015): the first true bench-top 3D bioprinter with Clean Chamber Technology (http://www.cellink3d.com/)
With a HEPA filtered positive air pressure inside the printing chamber, it is sure that the bioprinting is sterile.
11/17/2016 Presentation, Lamar University, 2016 47 LU: Recent acquisitions
We recently acquired a MakerBot Desktop 3D Printer which uses PLA material to be extruded into layers. We also recently acquired an Inkredible printer. We have also designed, implement, and test two DIY 3D printers: Ultimaker and PrntBot http://galaxy.lamar.edu/~sandrei/Ultimaker/index.html
11/17/2016 Presentation, Lamar University, 2016 48 Makerbot Replicator Z18
11/17/2016 Presentation, Lamar University, 2016 49 College of Arts and Sciences’ Facebook
11/17/2016 Presentation, Lamar University, 2016 50 Example
… of an innovative and unique way for content, mode of delivery and pedagogy of teaching courses using 3D printed artifacts. To the best of our knowledge, all ‘Foundations in Computer Science’ courses are currently taught like this:
A pushdown automata is a 7-tuple M = (Q, , , q0, Z0, A, ), where Q is a finite set of states, the input and stack alphabets and are finite sets, q0 Q is the initial state, Z0 is the initial stack symbol, A Q is the set of accepting states, and the transition function is : Q ( {}) the set of finite subsets of Q *.
A configuration of a PDA is a triple (q, x, ), where q Q is the current state, x * is the portion of the input string that has not yet been read, the contents of the stack is *.
According to the student evaluations and other sources, most of students struggle to understand this complicated concept (and the configuration transitions).
11/17/2016 Presentation, Lamar University, 2016 51 Our approach is 3D-model oriented…
The below photos show a group of students explaining the concept of pushdown automata with the help of a physical 3D printed artifact, the behavior of a pushdown automata becomes crystal clear (COSC 3302 – Introduction to Computer Theory) – Mr. Tim Gonzales
11/17/2016 Presentation, Lamar University, 2016 52 Student assessment about this concept
While the definition of the pushdown automata looked complicated, once they’ve seen the 3D printed artifact, the students have now a very clear understanding and using the concept of pushdown automata.
11/17/2016 Presentation, Lamar University, 2016 53 Case Study: COSC 5328 Real Time Systems A game board for Example of slide 5
The below figure shows the scheduling game board representation of this task set at time i = 0. The x-axis shows the laxity of a task and the y-axis shows its remaining computation time.
11/17/2016 Presentation, Lamar University, 2016 54 Scheduling single-instance tasks with game board Let C(i) denote the remaining computation time of a task at time i, and let L(i) denote the laxity (slack) of a task at time i (i.e., L(i)=D(i)-C(i)-S(i)). On the L-C plane of the scheduling board, executing any n of the m tasks in parallel corresponds to moving at most n of the m tokens one division (time unit) downward and parallel to the C-axis. Thus, for tasks executed: L(i+1) = L(i), C(i+1)=C(i)-1 Tokens corresponding to the remaining tasks that are not executed move to the left toward the C-axis. Thus, for tasks not executed: L(i+1) = L(i)-1, C(i+1)=C(i)
11/17/2016 Presentation, Lamar University, 2016 55 Rules for the Scheduling Game Board
Each configuration of tokens on the L-C plane represents the scheduling problem at a point in time. The rules for the scheduling game are: Initially, the starting L-C plane configuration with tokens representing the tasks to be scheduled is given. At each step of the game, the scheduler can move at most n tokens one division downward toward the horizontal axis. The rest of the tokens move leftward toward the vertical axis. Any token reaching the horizontal axis can be ignored (it has completed its execution). The scheduler fails if any token crosses the vertical axis into the second quadrant before reaching the horizontal axis. The scheduler wins if no failure occurs.
11/17/2016 Presentation, Lamar University, 2016 56 EDF scheduler fails (ex. From slide 5)
Example of two-processor system (n = 2) for three single-instance non-preemptive tasks:
J1: S1 = 0, c1 = 1, D1 = 2
J2: S2 = 0, c2 = 2, D2 = 3
J3: S3 = 0, c3 = 4, D3 = 4
J1 and J2 have earlier absolute deadline, so they are assigned to start.
11/17/2016 Presentation, Lamar University, 2016 57 LL scheduler wins (ex. From slide 5)
Their laxities are l1 = 1, l2 = 1, and l3 = 0.
At time 0, J3 has the lowest laxity, so it is assigned to start.
The other one can be J1 (since it has same laxity as J2).
11/17/2016 Presentation, Lamar University, 2016 58 LLF is not optimal
Example of two-processor system (n = 2) for six single-instance non-preemptive tasks:
J1: S1 = 0, c1 = 2, D1 = 2
J2: S2 = 0, c2 = 2, D2 = 2
J3: S3 = 0, c3 = 3, D3 = 6
J4: S4 = 0, c4 = 3, D4 = 6
J5: S5 = 0, c5 = 1, D5 = 5
J6: S6 = 0, c6 = 1, D6 = 5
Their laxities are sorted increasingly: l1 = 0, l2 = 0, l3 = 3, l4 = 3, l5 = 4, l6 = 4.
This is because tasks J1 and J2 will be chosen to be first executed on processors 1 and 2, respectively.
Then, J3 and J4 will be scheduled for processors 1 and 2, but tasks J5 and
J6 cannot be scheduled because they will miss their deadline of 5.
11/17/2016 Presentation, Lamar University, 2016 59 However, EDF is optimal for previous example
We re-arrange the jobs according to earliest deadline first strategy:
J1, J2, J5, J6 ,J3 and J4 This arrangement will lead to a feasible schedule.
11/17/2016 Presentation, Lamar University, 2016 60 EDF and LLF are not optimal for multiprocessor non-preemptive case Three-processor system (n = 3) for seven single-instance non- preemptive tasks:
J1: S1 = 0, c1 = 2, D1 = 2
J2: S2 = 0, c2 = 7, D2 = 7
J3: S3 = 0, c3 = 8, D3 = 9
J4: S4 = 0, c4 = 3, D4 = 6
J5: S5 = 0, c5 = 1, D5 = 5
J6: S6 = 0, c6 = 5, D6 = 12
J7: S7 = 0, c7 = 3, D7 = 11
Their laxities are: l1 = 0, l2 = 0, l3 = 1, l4 = 3, l5 = 4, l6 = 7, and l7 = 8.
LLF assigns J1, J2, and J3 to processors 1, 2, and 3, respectively.
Then J4 is executed by processor 1.
Hence, J5 will miss its deadline.
11/17/2016 Presentation, Lamar University, 2016 61 EDF and LLF do not work for previous example, but there is a feasible schedule!
EDF assigns J1, J5, and J4 to processors 1, 2, and 3, respectively.
Hence, J2 will miss its deadline. But … is the previous task set feasible? Actually, it is … the feasible schedule is:
First, J1, J2, and J3 to processors 1, 2, and 3, respectively.
Then, J5, J6, and J7 are executed by processors 1, 2, and 3.
Finally, J4 is executed by processor 1.
11/17/2016 Presentation, Lamar University, 2016 62 Causal Order in the Declarative Model
In a concurrent program all execution states of a given thread are totally ordered. The execution state of the concurrent program is partially ordered. thread T3
thread T2 fork a thread
thread T1 computation step
11/17/2016 Presentation, Lamar University, 2016 63 3D model for teaching the scheduling problem for multiprocessor platform
Example of two-processor system (n=2) for three single-instance tasks: J1: S1 = 0, c1 = 1, D1 = 2 J2: S2 = 0, c2 = 2, D2 = 3 J3: S3 = 0, c3 = 4, D3 = 4
11/17/2016 Presentation, Lamar University, 2016 64 Case Study: COSC 3308 Programming Languages Concepts Causal Order in the Declarative Model
synchonize on a dataflow variable
bind a dataflow variable thread T3 x
thread T2 fork a thread y
thread T1 computation step
11/17/2016 Presentation, Lamar University, 2016 65 Nondeterminism
An execution is nondeterministic if there is a computation step in which there is a choice what to do next. Nondeterminism appears naturally when there are multiple concurrent states.
11/17/2016 Presentation, Lamar University, 2016 66 3D model for teaching the ‘fork and join’ concept
. In parallel computing, the fork–join model is a way of setting up and executing parallel programs, such that execution branches off in parallel at designated points in the program, to "join" (merge) at a subsequent point and resume sequential execution.
11/17/2016 Presentation, Lamar University, 2016 67 Bucket Sort and Radix Sort (COSC 2336 – Data Structures)
All sort algorithms discussed so far are general sorting algorithms that work for any types of keys (e.g., integers, strings, and any comparable objects). These algorithms sort the elements by comparing their keys. The lower bound for general sorting algorithms is O(n · log n). So, no sorting algorithms based on comparisons can perform better than O(n · log n). However, if the keys are small integers, you can use bucket sort without having to compare the keys.
11/17/2016 COSC-2336, Lecture 6 68 Bucket Sort and Radix Sort (cont)
Bucket sort, or bin sort, is a sorting algorithm that works by partitioning an array into a number of buckets. Each bucket is then sorted individually, either using a different sorting algorithm, or by recursively applying the bucket sorting algorithm. It is a distribution sort, and is a “cousin” of radix sort in the most to least significant digit manner. Since bucket sort is not a comparison sort, the Ω(n · log n) lower bound is not applicable. The computational complexity estimates involve only the number of buckets.
11/17/2016 COSC-2336, Lecture 6 69 Bucket Sort The bucket sort algorithm works as follows. Assume the keys are in the range from 0 to N-1. We need N buckets labeled 0, 1, ..., and N-1. If an element’s key is i, the element is put into the bucket i. Each bucket holds the elements with the same key value. Given n the number of integers, the worst-case time complexity of the bucket sort algorithm is O(n). More precisely, it is n · N · D, where D is the maximum number of digits of the given integers. You can use an ArrayList or a Bag to implement a bucket.
Elements Elements Elements … Elements with key 0 with key 1 with key 2 with key N-1
bucket[0] bucket[1] bucket[2] bucket[N-1]
11/17/2016 COSC-2336, Lecture 6 70 Bucket Sort (cont) Sort 331, 454, 230, 34, 343, 45, 59, 453, 345, 231, 9
230 331 343 454 45 59 231 453 34 345 9
bucket[0] bucket[1] bucket[2] bucket[3] bucket[4] bucket[5] bucket[6] bucket[7] bucket[8] bucket[9]
230, 331, 231, 343, 453, 454, 34, 45, 345, 59, 9
9 230 343 453 331 45 454 231 345 59 bucket[0] bucket[1] bucket[2] 34 bucket[4] bucket[5] bucket[6] bucket[7] bucket[8] bucket[9] bucket[3] 9, 230, 331, 231, 34, 343, 45, 345, 453, 454, 59
9 34 230 331 453 45 231 343 454 345 59 bucket[5] bucket[9] buckets[3] buckets[4] bucket[0] bucket[1] bucket[2] bucket[6] bucket[7] bucket[8] 9, 34, 45, 59, 230, 231, 331, 343, 345, 453, 454
11/17/2016 COSC-2336, Lecture 6 71 The 3D-printed artifact for bucket sort
11/17/2016 Presentation, Lamar University, 2016 72 3D LU logo approval
11/17/2016 Presentation, Lamar University, 2016 73 LU logo, LU nut and bolt, and the mechanical clock
11/17/2016 Presentation, Lamar University, 2016 74 Methyl methacrylate (C5H8O2 )
11/17/2016 Presentation, Lamar University, 2016 75 A medical weekly planner
11/17/2016 Presentation, Lamar University, 2016 76 Photos taken by Ms. Paula Gregory
11/17/2016 Presentation, Lamar University, 2016 77 LU cup, cell-phone holder, LU avatar
11/17/2016 Presentation, Lamar University, 2016 78 Inkredible 3D printer
The creators of the INKREDIBLE started their company with CELLINK, a bioink that has become the most widely used bioink in the world thanks to its excellent biocompatibility, printability, and structure that ensures 98% cell viability (study made with RoosterBio cells at Chalmers University in Sweden) – September 2015. Another great feature of the INKREDIBLE is its clean chamber technology. The printer has a highly filtered air flow with positive pressure created inside the chamber so it reduces contamination and particle count inside the printing area basically down to zero. The bioprinting services that CELLINK provides has been a great success for many partners and the fact that these partners can receive cell specific expertise enables for new proprietary tissue model creation for internal product development testing platforms.
11/17/2016 Presentation, Lamar University, 2016 79 The newly optimized desktop bioprinter for the ultimate bioprinting of human tissues and 3D cell culturing
11/17/2016 Presentation, Lamar University, 2016 80 Our INKREDIBLE at LU (calibrating and then printing a human ear) – Mr. Greg Yera
Less than 4% universities worldwide purchased BioInkredible. Wollongong University in Australia and Leading schools in South Korea and Switzerland.
11/17/2016 Presentation, Lamar University, 2016 81 Assembling the Ultimaker 3D printer and designing 3D-printed artifacts (Mr. Vraj Pandya)
11/17/2016 Presentation, Lamar University, 2016 82 https://3dprint.com/19305/biobots-3d- bioprinter/
11/17/2016 Presentation, Lamar University, 2016 83 The V. W. Keck Printing Center at UTEP
11/17/2016 Presentation, Lamar University, 2016 84 Future of 3D printing
Richard D’Aveni, The 3-D Printing Revolution. 3-D Printing Will Change the World, Harvard Business Review-Innovation, May 2015, [available online at https://hbr.org/2015/05/the-3-d-printing- revolution]
Industrial 3-D printing is at a tipping point, about to go mainstream in a big way. Most executives and many engineers don’t realize it, but this technology has moved well beyond prototyping, rapid tooling, trinkets, and toys.
“Additive manufacturing” is creating durable and safe products for sale to real customers in moderate to large quantities.
It may be hard to imagine that this technology will displace today’s standard ways of making things in large quantities. Traditional injection- molding presses, for example, can spit out thousands of widgets an hour.
11/17/2016 Presentation, Lamar University, 2016 85 Our plan at LU on 3D printing
11/17/2016 Presentation, Lamar University, 2016 86 Engaging students, staff, and instructors in the 3D-printing based learning and teaching at LU
1. Think for an initial idea of a 3D model with the functionality described in lecture notes 2. Check the existing databases of 3D models 3. While (prototype needs changes) {
1. Design the 3D software model (e.g., Blender)
2. Print a 3D model, a.k.a., prototype (e.g., Makerbot)
3. Test the prototype, ask feedback from students/colleagues/ collaborators 4. }
5. Collaborate with other departments/universities/institutions 6. Create a database with STL 3D files published under the Creative Commons License
11/17/2016 Presentation, Lamar University, 2016 87 Thank you for your attention!
Questions?
11/17/2016 Presentation, Lamar University, 2016 88