Mallard TM : Asynchronous Learning in Two Engineering Courses

Transcription

1 Mallard TM : Asynchronous Learning in Two Engineering Courses Michael L. Swafford, Charles R. Graham, Donna J. Brown, Timothy N. Trick University of Illinois at Urbana-Champaign Abstract Mallard TM is a World Wide Web based interactive learning environment suitable for use in a wide variety of courses. Mallard TM provides a secure environment within which one can organize online course material and test students via interactive quizzes with instantaneous problem correction and grading. In addition, Mallard TM provides administrative utilities for tasks such as maintaining class rosters, recording grades, and viewing up-to-the-minute tables of student progress. Mallard s TM open design allows flexibility and easy expansion. Mallard TM is currently being used in a number of courses; we describe its use in two engineering courses at the University of Illinois at Urbana-Champaign. The reader is encouraged to access our Web-site at: 1. Overview of Mallard TM Mallard TM is a collection of WWW documents and programs that provides students and instructors with a complete and customizable asynchronous learning environment suitable for virtually any subject. Mallard TM provides a secure environment within which one can organize online course material and test students via interactive quizzes. Student responses to these online WebQuizzes TM are evaluated by intelligent grading programs that not only assess the correctness of a response, but also determine why an answer is incorrect. To facilitate grading different types of questions, Mallard TM has an open design that facilitates the seamless integration of new types of question and grading programs. For each course using Mallard TM, every student has her own homepage, which she accesses via login and password. The content of the homepage is selected by the course instructor, and serves as a virtual classroom for the student. From this homepage the student can view basic course information, access a course newsgroup, send to an instructor, read lesson material, do practice exercises, or take a quiz. Moreover, because it is her own homepage, specific information (such as grade data) can be individually tailored. Furthermore, when a student submits a quiz online, she gets immediate feedback and can access online assistance if desired. Mallard TM also has many features that are attractive from a course administration perspective. Course material can be customized by instructors for individual courses. There is a WWW interface to many administrative functions, such as maintaining current rosters, up-to-the-minute information on student progress, logfiles to track student usage and posting or modifying due dates. Moreover, since quizzes are submitted and graded online, the instructor does not have to collect, correct, or even record grades for Mallard TM quizzes. Oakley s CircuitTutor [1] is a nice example of non-www-based software for an introductory circuits course. Compared to traditional software, use of the WWW offers a number of benefits for computer-aided education. Since there is only one copy of the course software (on the WWW server), students are guaranteed to be using the newest version. Instructors can update course content daily, as opposed to once a semester. The WWW browser is the only machine-specific component used to access the WWW, and third parties readily provide WWW browsers for virtually every type of computer. This ability to access course software from any platform was found by Carver and Howard [2] to be essential in order for students to get maximum benefit. Mallard TM assists student learning via tutorials and WebQuizzes TM. These WebQuizzes TM are written in a simple extension to HTML and are interactive, online quizzes that correct and record student responses to given questions. Recent versions of Mallard TM give course instructors great control over the grading policies and allow them to specify grading constraints such as pass/fail or letter grade cutoffs, late penalties, and the number of times a WebQuiz TM can be taken for credit. Using this flexibility instructors can create Mallard TM homework that is graded leniently as well as more strictly graded mastery quizzes. Each WebQuiz TM is an HTML form consisting of one or more questions. These questions can either be randomly generated (if appropriate) or randomly selected from a pool of questions. As a result, different students will see different quizzes, and the same student will see a different quiz each time she retakes a WebQuiz TM.

2 A more detailed description of Mallard TM was given in [3]. In the following sections, we describe Mallard s TM use in two engineering courses at the University of Illinois at Urbana-Champaign. 2. Freshman Electrical and Computer Engineering Course: ECE 110 is a 4 credit hour freshman engineering course. The course is designed to introduce students to a broad range of electrical and computer engineering concepts. It is a semester course with 3 lecture hours and 3 laboratory hours weekly. Students enrolled in the course learn basic electrical and computer engineering principles in class, and then apply those principles in the laboratory where they build an autonomous vehicle capable of navigating a path marked with reflective tape. In past semesters, homework problems were assigned from the textbook approximately twice a week; the problems were graded and returned to the students several days after submission. In the 1996 Spring Semester, Mallard TM lessons were used in place of the traditional textbook homework assignments. A total of 23 lessons were generated to reinforce the concepts presented in the lectures. Each of the lessons contained 1-2 brief tutorials and 2-7 homework problems. On average, the students were assigned two lessons each week and given approximately four days to complete each lesson. Homework problems were graded within seconds of submission. Students were given unlimited attempts to correct wrong answers. However, if a homework problem was completed after the due date, the grade for that problem was reduced by 50%. The students could also use the newsgroup in Mallard TM to post questions. Often other students answered questions even before the instructor. The material taught in the course can be divided into three distinct parts. The first part covers voltage, current, power, energy, electromagnetic devices, Kirchhoff s Laws, dc circuit analysis, equivalent circuits, and capacitor and inductor waveforms. The second part of the course covers topics relating to electronic devices, including i-v characteristics, graphical solutions, simple large signal diode models, and the bipolar and MOS transistors. The third part of the course covers digital circuits and systems, including combinational logic, sequential logic, memory, and a simple RISC microprocessor. Using Mallard TM, students showed their mastery of these principles by completing problems such as the one displayed in Figure 1. This node voltage problem demonstrates the use of three different problem types in Mallard TM. First, the student enters two linear equations for the circuit provided. A simple matrix solver checks the two linear equations against the correct solution. If the answer the student submits is incorrect, Mallard TM will provide the student with additional feedback such as telling the student if his equations were not linearly independent. In the second group of blanks the student calculates the numerical solution for the voltages in the circuit by entering either a number or an arithmetic expression to be evaluated by Mallard TM. The last question is a multiple choice problem type. In the lessons on electronic devices, students practiced using large signal models to analyze zener and photodetector diode circuits. Tutorials and homeworks dealing with BJTs taught the students how to analyze a simple non-linear inverter circuit in order to determine its transfer characteristic and its current gain and voltage gain. In the digital, section students were taught how to generate truth tables for logic circuits, fill in timing diagrams, do base conversions, minimize boolean equations, and analyze the timing for circuits containing elements such as counters, comparators, and multiplexers. The students also did some problems dealing with assembly coding for a simple RISC microprocessor. At the end of the course the students were surveyed and asked how they had liked using the Mallard TM system. The general response was positive. Students liked the immediate feedback and the opportunity to go back and correct wrong answers while the problem was fresh in their minds. Also, at the end of the semester the students found it convenient to review the lessons in Mallard TM and rework the problems as a preparation for the final examination. A few students, however, viewed Mallard TM as a task to be completed instead of as a learning tool. These students would often submit random guesses to Mallard TM until they achieved a certain score on the WebQuiz TM. We hope to solve this problem in the Fall 1996 semester by placing a reasonable limit on the number of times a WebQuiz TM can be submitted for credit and stressing to the students that Mallard TM is a learning tool instead of just a task to be completed. From an administrative point of view, Mallard TM eliminated the hassle of collecting, grading, and returning homework papers. This is especially advantageous due to the large class size, and compensated for the substatial amount of work required to develop online course material. The grade report not only provided the student grade for each problem, but also the number of attempts made by the student. This gave the instructors feedback as to which students were struggling with the material and also which concepts were the most difficult for the students to grasp. Finally, there was a perception among the instructors who have

3 Figure 1: Example of a Kirhhoff's Law Problem in Mallard TM taught the course, both in the traditional manner and also using Mallard TM, that students obtained a better understanding of fundamental concepts when Mallard TM was used. 3. Introduction to Computer Engineering Course ECE 290 is a 3 credit hour sophomore-level course, required of all students majoring in electrical or computer engineering. The course covers the classic topics of combinational and sequential design, then proceeds to the design of a simple computer. It is a semester course with 2 hours of lecture and 1 hour of discussion each week: total enrollment runs over 200, with about 30 students per discussion section. There are weekly homework assignments; biweekly computer laboratory assignments, in which students utilize commercial CAD software in order to simulate logic design concepts and then a small microprogrammed CPU; and two or three in-class hour exams plus a final. Thus far, more than 35 Mallard TM lessons have been developed for ECE 290, replacing approximately half of the paper homework. The Mallard TM WebQuizzes TM helped students learn basic skills and provided an almost unlimited supply of exercises. Students were allowed to retake a WebQuiz TM as many times as they desired, in order to obtain a perfect score. When a student answered a problem incorrectly, she could receive feedback indicating the type of error she had made. She could then go back, correct any wrong answers, and resubmit them for grading as many times as needed. However, in order to receive credit, the student had to reload a new version of the WebQuiz TM ; this new version consisted of different but similar problems. Hence, each student had her own version of the WebQuiz TM. This strategy reinforced the common advice to work together but then do the problem yourself. Due to the variety of question types needed, computer engineering poses some challenges for automatic problem grading. Mallard s TM open design allowed new problem types to be easily integrated and, indeed, a new problem type was introduced almost every week. Mallard TM WebQuizzes TM included the following topics: code conversions, 2 s complement arithmetic, Boolean property drills, filling in truth tables, Karnaugh maps, canonical and minimal sum-of-products (or product-of-sums) form, timing diagrams, analysis of state diagrams, sequential analysis, addressing modes, reverse Polish notation, etc. In all cases, problems were either randomly generated (e.g. to convert an arbitrary decimal number into 2 s complement form) or randomly selected (as in Figure 2). In the sample question in Figure 2, students must analyze a sequential circuit. In the first question, the student is asked to complete the next-state table by entering 0 or 1 into each blank. The second question asks the student to give a minimal SOP Boolean expression for the flip-flop input T. If the student answers incorrectly, she is given feedback as to whether her expression is functionally correct, whether it is in

4 Figure 2: Example of a Sequential Circuit Analysis Problem in Mallard TM SOP form, and whether it is minimal. The second question also asks the student to give a Boolean expression for z; x+y is the answer, but any functionally equivalent response (e.g. y +x+y or (y +0+x)(y +x)) would also be correct. From an instructor s viewpoint, the administrative features eased the burden of teaching a large class. New WebQuizzes TM were first available on Mallard TM only to staff (and were flagged as under construction to students); as soon as staff had had a chance to debug the problems, they were made available to students. Students very much liked the immediate feedback provided by Mallard TM. Pedagogically, transferring a number of the routine problems to Mallard TM enabled instructor/student time to be focused on tasks which demand human insight, such as critiquing student designs. Mallard TM was used on a limited basis for a single discussion section during Fall Interestingly, this section outperformed all seven other sections by about 10 points (a full letter grade) on the first hour exam; specifically, there were no students in the bottom quartile of the class. In Spring 1996, the expanded Mallard TM offering was required for all students. 4. Conclusion In our experience, Mallard TM has proven to be a very effective educational tool. Students get immediate feedback on the WebQuizzes TM. Instructors have a secure environment for their course material, and many administrative features to ease the burden of teaching large courses. In the coming semesters, we plan to continue to develop course material and include new technologies such as Java. While we have described using Mallard TM in only two engineering courses, the number of courses using Mallard TM is growing rapidly, and subjects include engineering, materials science, economics, computer science, and Italian. Link: References HTML demo of the Mallard system [1] B. Oakley II, Use of the Internet in an introductory circuit analysis course, Proceedings of the ASEE/IEEE Frontiers in Education 93 Conference, Washington, DC, November [2] C. Carver and R. Howard, An assessment of networked multimedia and hypermedia, Proceedings of the ASEE/IEEE Frontiers in Education 95 Conference, Atlanta, GA, November 2-4, [3] M. Swafford and D. Brown, Mallard TM : Asynchronous Learning on the World-Wide Web, Proceedings of the ASEE 96 Conference, Washington, DC, June 23-26, 1996.

5 Acknowledgements The authors wish to thank Maiko Covington for endless hours spent in preparing the Mallard demo, Ed Kubaitis for his expertise with our secure server, and hundreds of other Mallard users. We are grateful for financial support provided by the University of Illinois, the Department of Electrical and Computer Engineering, and the Sloan Center for Asynchronous Learning Environments (SCALE).