ADHAMI, Reza R., & ARRINGTON, Christina E. H.
Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, Alabama 35899, www.eb.uah.edu\ece\
Abstract: Most engineering departments have a curriculum in which students spend the first two years taking science and mathematics courses. Students find themselves as juniors with little or no idea of what one can do with a degree in their field. This is highly unfortunate since the freshman and sophomore year experiences are crucial in the student's decision of a major. Without an accurate idea of what is possible in their engineering field, students may become discouraged with their major and be persuaded to study another field to which they have had more exposure.
The Electrical and Computer Engineering Department at the University of Alabama in Huntsville has developed a plan to introduce students from different disciplines to practical applications of theories they normally would not encounter until their junior or senior year of engineering. The plan has increased student interest in engineering and has shown a great success in retaining students in the Department.
This conceptual, hands-on course offered at the beginning of students' careers provides them a vision of what to expect in later courses and in their chosen field. Seeing the skills that will be required later motivates the students to retain more of the material in their science and mathematics courses. Being exposed to the concepts in engineering early will prevent students from feeling separated from the college of engineering during their first two years. They can become more settled in their choice of major early on, begin to see themselves as an engineer, and strive more purposefully towards that goal.
Keywords: interactive, freshman, course, engineering
Normally, engineering students are two years into their college career before they begin to take engineering courses. They spend these years in mathematics and science courses such as calculus, linear algebra, and physics. These courses are foundational to engineering, but since they are taught mostly at the freshman and sophomore level before students are familiar with concepts in engineering, students are unable to see the connection between their class material and their eventual career. This results in lower retention of the course material and lower retention of students in the field.
Engineering is applied mathematics. However, if the mathematics is taught without any reference to the myriad of applications in engineering, the power of motivating students through association is lost. Combining the course material with engineering applications allows students to associate the skills they are currently being taught with the innumerable applications in engineering that require those skills. Students are more motivated to learn when they see the reason for learning.
In addition, the freshman and sophomore years are crucial in the student's decision making process. Students evaluate their choice of major based upon the courses taken during the first two years [1]. If the courses are uninteresting, or the student gets discouraged due to low grades, the student will consider choosing another major. Most engineering faculty view this as "weeding out" the students unfit for engineering. However, it is very likely that too many students are weeded out, not because they are unfit for engineering, but because they do not have an accurate picture of their major. One author can honestly say she did not start to receive a clear picture of the field of electrical engineering until graduate school. This is highly unfortunate when students choose their major within the first two years. Engineering has a distinct disadvantage in this arena over other fields. One can easily imagine what an education, nursing or business major will eventually be doing. However, very few people outside of engineering clearly understand what engineers accomplish, much less the differences between each field. Plus, few engineering students are exposed to recent research and the present day problems of application. When describing current research topics in electrical engineering to students, too many of them question, "That's a part of engineering?" Students are more motivated in their studies when they are excited about their field. Unfortunately, a large portion of juniors and seniors in engineering do not have a clear and complete picture of what their chosen field encompasses.
Every academic field in existence today arose to satisfy a need. There are problems that need to be solved, opportunities for research, and practical applications of that research that only electrical and computer engineers can solve. That is why the field still exists today. This is our motivation and this needs to be the motivation for our students as well. This needs to be presented to the students within the first two years. They need to make their decisions based upon accurate information of their engineering field, not based upon a lack of information.
Anytime students take a course without seeing a need for the skills later on, many will learn the material only for the test and not for future retention. Usually they perform a "brain dump" after the final exam. Later, when these students are in an engineering course that requires those skills, they are at a lost. The engineering professor can either leave half of the students behind or spending precious time reteaching the material. Ideally, mathematics, science, and engineering courses would be fully integrated to teach the applications along with the skills. However, as this is unrealistic for many universities, a second alternative is to offer a freshman course that presents many of these applications along with references to the mathematics and science skills required for their solution. Students gain an understanding of the type of problems tackled in the field and get a chance to solve some of those problems in class using software. Without understanding all the mathematics involved, students are exposed to the problem and what is required for the solution. Later, in their advanced courses, they will learn the skills necessary to fully understand the problem. When they see a reason to learn the skills, student attention and retention rises.
Students are introduced to state-of-the-art simulation and visualization tools that are widely used in research and industry. In developing EE100: Concepts in Digital Signals and Systems, Dr. Reza Adhami drew from his years of experience teaching graduate level courses in digital signal processing, digital speech processing, and digital image processing. Problems such as tomography and pattern recognition have been incorporated into EE100. The students are not expected to solve the problems on their own, add to the solution, or even understand all the mathematics behind the solution. But they are expected to conceptualize the problem and comprehend the solution while gaining an appreciation for the skills required.
The students apply the solution using the software packages available and test whether it works. This allows them to visualize the solution as well as giving them a chance to determine how different factors affect the output in different ways. Much of the world's gain in knowledge has been through trial and error. Simulation tools give the students the chance to learn through trial and error while gaining intuition into the problem. This method has a secondary advantage in that the students learn various software programs such as Microsoft Word, Powerpoint, MATLAB, and Electronics Workbench without specifically teaching those tools.
Since no prior computer knowledge is assumed for EE100, the students are introduced to the computer hardware and software during the first week of class. The main components of the computer are discussed including the central processing unit, motherboard, bus, expansion slots, hard drive, floppy drive, CD-ROM drive, sound card, and RAM. Then in the Student Project Lab, students are expected to disassemble a computer, label all the parts and reassemble the computer. The instructor also provides information regarding computer evolution. Also discussed are common operating systems and a basic history of their development.
This portion of the course is designed to make the student aware that signals exist everywhere. Students are introduced to different types of signals and systems. The differences between continuous-time and discrete-time signals are discussed. The basic process of converting an analog signal into a digital signal is covered. Methods for storing digital data are presented. Sampling, periodic waveforms and binary numbers are also discussed.
Students are introduced to the basic properties of sound waves. The process involved in recording a sound wave (analog-to-digital conversion) is explained. They then record their own voice. The resulting waveform is loaded into MATLAB as an array, displayed and ready for processing. By plotting 20 ms of their speech, they observe the periodic waveform. The fundamental frequency (or pitch) is discussed. The students then calculate the pitch of their voice. The students model the echo process using a simple first-order difference equation. The equation is applied using M-files in MATLAB. They are introduced to the concept of the frequencies contained in a signal. Through low-pass and high-pass filtering of the recorded voice, students learn where most of the information in speech is located. Filtering also provides a platform to mention the convolution integral, linear systems, and transfer functions.
Images are used to introduce the concept of two-dimensional array, or matrices. Students learn to access and modify blocks of an image. They learn about the two-dimensional filtering process using convolution masks and median filters. Since an edge in an image represents high frequency signals, filtering through convolution masks leads into edge detection along with the concept of derivatives. Also discussed is how one could use edge detection in the process of pattern recognition. Various forms of random noise is added to an image and removed using different types of filters. The student can observe how noise affects an image and how filtering enhances a noisy image.
Electrical elements such as resistors, inductors, capacitors, op-amps, etc., are presented along with voltage and current sources. At this level, the presentation includes word pictures and analogies to help students comprehend these abstract concepts for the first time. Then using Electronics Workbench, students view the relationships between current, voltage and resistance. By building circuits and measuring the values, they derive Ohm's Law. Other topics covered include resistances in series and parallel, voltage and current division, AC and DC circuits, and non-linear devices such as the diode, transistor and op-amp. All of these topics are covered in a hands-on manner where the student builds and measures the values involved.
Students are taught the binary number system and introduced to the basic set of digital logic gates. They are introduced to Boolean Algebra and its relationship to truth tables and the logic gates. Minterms are also discussed along with the basics of designing circuits from a truth table using the sum of products. Using Electronic Workbench, they then design a logic circuit for a given truth table.
During the semester, students are given the choice of working on either a hardware or software project. The hardware projects consist of a kit ordered through an electronics distributor. Students learn how to solder and then solder together their kit. Students are required to test their kit for proper operation. Once they've gone through the debugging process and confirm the specified operation, students research how the circuit works. This is presented in a written report as well as an oral presentation to all students in the class.
Students have a option of choosing a software project from a suggested list. The list includes topics such as simple image processing, DTMF (Dual Tone Multiple Frequency), controlling equipment from a parallel port, and others. They can complete this project using either FORTRAN, C, or MATLAB.
In addition to the material presented in the class, students are required to work on their communication skills as well. At the beginning of each class, one student makes a 5-minute presentation outlining what was covered in the previous class. They are free to use visual aids, the whiteboard, and any additional information they may have gathered on their own. Depending upon the class size, students may receive two opportunities to present. Prior to their final project presentation, the instructor covers the basic rules of oral presentations. This prepares them not only for their final presentation but also for the workplace where they will have to present their work and convince others of its value.
A specialized classroom was developed specifically for EE100. Each student sits behind a computer loaded with visualization and simulation application software such as Electronic Workbench and MATLAB. In the course of the semester, students also use Microsoft Word, and PowerPoint. The lectures are given using a computer and an LCD projector. Using this teaching environment, the students are able to duplicate the instructor's examples. PowerPoint slides and demonstrations on the computer comprise approximately 80% of each class. A web page is designed that contains the course syllabus and the PowerPoint Presentation files used during lecture. Additional background information is also provided which will become the basis for a textbook in the near future.
Though students are required to use MATLAB, Microsoft Word, PowerPoint and Electronics Workbench, these software programs are not taught explicitly. While students are learning the concepts of speech processing and image processing, they work examples in MATLAB and thus learn the software on the side. The instructor is always available in the classroom to help the students fill any deficiencies in computer literacy. Prior knowledge of these programs is not assumed, nor is prior computer experience. Students who fall behind during an example will very rarely speak up, thus the instructor walks around the classroom often to make sure all the students are on track.
One common example in EE100 is teaching the students what is required to model an echo in speech. MATLAB is used to perform this operation. Students may record their voice and store it in a wave file or they may use a prerecorded wave file. Once in MATLAB, students read in the wave file, generating an array containing the signal values at various points in time. The sampling frequency of the signal is also read in and stored. The students generate a delayed copy of the original signal by creating a new array that is padded by a specified number of zeros in the front. The number of zeros needed for a certain time delay can be calculated from the sampling frequency and the time delay required. This delayed signal is attenuated by multiplying the array with a constant value between zero and one. Since arrays of different lengths cannot be added, the original signal is also padded with the same number of zeros, but these are appended at the end of the array. Then the delayed and attenuated signal is added to the original signal. Students play this signal to hear the echo. They also plot the original and modified signals to visually see how the echo modified the signal.
As this stage the course has only been taught for 4 semesters. For this reason, long term assessment of the increase in student retention in electrical engineering as a direct result of this course is premature. However, preliminary results are very encouraging. Student feedback has been very positive. Many juniors and seniors have commented that they wish this course had been offered when they were freshman. Even students who were nervous about the classroom presentations have remarked that they were glad they now had some experience presenting.
Teaching engineering subjects and concepts through visualization and simulation tools is perhaps the most effective way to give students a clear understanding of the material. Using application software allows freshman to consider graduate level problems in an undergraduate level course. This gives the students a better picture of what areas of study are available in the field which grants students the information necessary to make an informed decision early in their college careers. Giving them the big picture increases student interest in the field and provides motivation to persevere in the pursuit of their degree. It also provides motivation to retain the specific skills taught in their advanced courses. Overall, this course introduces students to engineering, educates them as to what the field entails, and equips them with the basic skills and knowledge for a successful undergraduate career.
HEWITT, N.M., & SEYMOUR, E. A Long Discouraging Climb. In Prism. February 1992, pp. 24-28.