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Richard G. Baraniuk and Wayne T. Padgett
Trends in Signal Processing Education
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his summary captures the ideas presented in the Trends session on Signal Processing Education (SPED) at ICASSP 2011. In that session, we surveyed a number of key areas of educational innovation and solicited other trends from the audience. While we strive to be as comprehensive as possible, there are quite likely to be gaps in our treatment. Although innovation in education is gaining momentum, the basic textbook/ lecture/homework teaching model still dominates. Founded on the need to efficiently deliver information from the expert to the novice, this approach usually fails to engage the learner at a level deeper than note taking. Most educational research shows that students learn faster and better when they are interacting with the material and when the lessons are customized to their needs. The textbook/lecture/homework model does little to take advantage of technology that can turn textbooks into an immersive experience, lectures into self-paced modules, and homework into customized interactive exercises. OPEN SOURCE EDUCATIONAL MATERIALS The Web is a powerful medium for sharing interactive content that can help educators break out of the traditional teaching model, but most of the extant content is proprietary and can only be repackaged or modified by the owners. Fortunately, there are some growing resources of high-quality materials that are available for reuse by anyone. Materials that are licensed with the Creative Commons Attribution (CCBy) license (one of the most open of the CC licenses) can be modified, repackaged, and even sold as long as attribution is given to the original author. The Digital Object Identifier 10.1109/MSP.2011.943132 Date of publication: 8 December 2011
Connexions Web site (http://cnx.org) contains modules that are designed to be assembled into large collections that can even span an entire textbook. The CC-By license enables the materials to be easily and legally repurposed to the local teaching context, for example matching the mathematical notation and nomenclature of a particular institution. Although Connexions is not limited to signal processing (currently its repository contains over 19,000 modules used by 2 million users per month), the signal processing community is well represented; the IEEE Signal Processing Society (SPS) Education
ALTHOUGH INNOVATION IN EDUCATION IS GAINING MOMENTUM, THE BASIC TEXTBOOK/LECTURE/ HOMEWORK TEACHING MODEL STILL DOMINATES. Committee even has a Connexions subcommittee that is performing peer evaluation of the materials (see the section “Peer Evaluation/Quality Control”). Contributors of signal processing material to Connexions include John Treichler, Louis Scharf, Sidney Burrus, Robert Nowak, and Stephane Mallat. There exist other open educational resources, but they have significant limitations. For instance, Wikipedia is limited to encyclopedic material that is not generally suitable for classroom use, and Massachusetts Institute of Technology (MIT) OpenCourseWare cannot be mixed and matched. VIDEO TUTORIALS Self-paced interaction is a key theme of this summary and one way to accomplish it is to put the pace of the lecture in the hands of the learner. Tutorial videos enable the student to control how fast the topics go by, and they allow repetition
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when needed, without risking embarrassment to the student. Powerful video recording tools (http://en.wikipedia.org/ wiki/Comparison_of_screencasting_software) allow individual professors to quickly produce videos to be viewed outside of class, so that valuable class time can be used to focus on student questions and interactive exercises. Ed Doering at the Rose Hulman Institute of Technology has pioneered video tutorial content for “Music Signal Processing” on Connexions (http://cnx.org/content/col10507) and developed circuits-related content in the National Science Foundation (NSF)sponsored Circuits Learned by Example Online (CLEO) project (http://www.rosehulman.edu/CLEO). Geoffrey Herman of the University of Illinois at UrbanaChampaign (UIUC) has suggested that video allows the instructor to turn the classroom “upside down”—having students view video lectures outside the classroom, and then doing homework during class time with the purpose of using the face-to-face class time more effectively in an interactive mode. Another celebrated proponent of introducing topics using video tutorials is Salman Khan, founder and sole teacher in the Khan Academy, a site with currently over 2,400 videos on a wide range of topics. Khan has partnered with K-12 teachers to develop interactive exercises and other educational software to enhance self-paced learning. INTERACTIVE SIMULATIONS Interactive simulations are an area where technology has improved dramatically. National Instruments’ LabView provides an environment where interactive elements like sliders, knobs, and graphs are easily integrated. Mark Yoder of Rose Hulman has produced a substantial library of signal processing demos for the Signal Processing First text, and Yoder and Padgett have created a similar set based on
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the figures of Oppenheim and Schafer’s Discrete Time Signal Processing, 3rd Ed. The Mathworks’ MATLAB has developed a publish function that makes it possible to demonstrate the output of a MATLAB demo and even extract the code from the resulting Web page. Wolfram Research’s Mathematica has recently introduced tools to automate the creation of interactive Web simulations, and the Java-Digital Signal Processing (J-DSP) tool is available for building interactive Web demonstrations as well. All these tools provide excellent facilities to create demonstrations that students can explore with their own initiative as a supplement to more traditional “one-answer” homework problems and exercises. Interactive simulations provide a middle ground between a typical homework problem and a traditional lab project. Although they are not as open ended as a physical lab experiment, they are accessible anywhere the student has computing access and on the student’s time schedule. QUESTION AND ANSWER DATABASES There are at least two projects underway to develop large sets of signal processing drill questions with known answers to help automate the process of assessing students and giving them rapid feedback on their understanding. James McClellan at Georgia Tech has helped develop a Signal Processing Question and Response (SPQR) system at Georgia Tech that contains over 1,000 questions. The Question/Answer database (http:// QuADbase.org) project at Rice is similar and is intended to provide a standardized format so that questions can be imported or exported through learning management systems and Connexions. Both systems will enable student performance tracking within a course and across an entire curriculum. They are also paving the way toward the development of intelligent tutoring sysSlides tems that choose question sequences and suggest feedback based on each student’s past performance.
PEER EVALUATION/ QUALITY CONTROL In an ideal world, experts from around the world would contribute educational resources of high quality, make them freely available, and make them easily discoverable by interested users. In reality, the currently available materials are of widely varying quality and need to be evaluated before use. The need for review reduces the value for users because of the time commitment necessary to find good material. Fortunately, the Connexions Subcommittee of the IEEE SPS Education Committee has established a process for evaluating materials so that users can be assured of its quality. Materials that are
THANKS TO THE RAPID ADVANCE OF INFORMATION TECHNOLOGY, NEW ALTERNATIVES TO CENTURIES-OLD TEACHING TECHNIQUES ARE BEING INTRODUCED AND TESTED ON A LARGE SCALE. judged by the evaluators to be correct and valuable for their intended audience are published in a special “lens” on the Connexions system; see http://IEEEcnx.org for more details. We encourage the reader to examine the material listed there for potential classroom use and to submit your own material to Connexions and the lens. Volunteers interested in evaluating material are also welcome. SIGNAL PROCESSING EDUCATION NETWORK The dream of building a community of Web-based educational resource users that would help build a comprehensive, carefully indexed, high-quality set of resources has come to life in the NSFsupported Signal Processing Education Network (SPEN) project. The project aims to bring together users and creators of Web content in the form of interactive simulations, video tutorials, question and answer databases, and education modules to build a self-sustaining community
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somewhat like the open source software community. With an index of content linked to the most popular DSP textbooks, it will be possible to identify gaps in the body of existing material and encourage new development in those areas. The next SPEN Workshop is planned for 22–24 February 2012. To learn more about how to participate, visit http://spenproject.org. THE WAY FORWARD We live in an exciting time for signal processing education. Thanks to the rapid advance of information technology, new alternatives to centuries-old teaching techniques are being introduced and tested on a large scale. While the jury is still out on which new teaching and learning approaches will ultimately dominate, it is clear that the way we conduct classroom education and professional development could be very different— and much more effective—just a few years from now. One final note: this brief summary of our Trends presentation has focused on just our views and should not be considered complete or exhaustive in any way. For example, the audience discussion at ICASSP pointed out that there has been interesting progress, for example, on hardware implementation and labs. Hopefully this and other topics will be included in future SPED Trends talks. ACKNOWLEDGMENT Special thanks to James McClellan for several useful discussions on key trends. AUTHORS Richard G. Baraniuk (
[email protected]) is the Victor E. Cameron Professor of Electrical and Computer Engineering at Rice University. He is also the founder and director of Connexions (http://cnx.org). Wayne T. Padgett (Wayne.Padgett@ Rose-Hulman.edu) is a Video professor of electrical and computer engineering at the RoseHulman Institute of [SP] Technology.
