Virtual experiments and group tasks in a Web-based collaborative course in Electronics Engineering
Lucio Teles and Tim Collings
Simon Fraser University - Canada
in Khan, B. (1997, Ed.). Web-Based Instruction. Englewood Cliffs: Educational Technology Publications.
This chapter discusses the design of an online version of an introductory course in electronics offered by the Department of Engineering Science, Simon Fraser University. The course will be delivered on Virtual-U, a Web-based conferencing system for educational applications. Students can access a "virtual lab" and conduct group work to develop competence in introductory electronics.
Introduction
As the campus student population increases, the existing lab can not accommodate the growth and give all students lab time to do experiments. At the same time, the Department of Engineering Science plans to make ENSC 25 available to "transfer students", those who come from colleges and typically need the prerequisite skills taught in ENSC 125.
ENSC 125, Electronics I, is a prerequisite course which currently is offered only on campus with face-to-face course sessions and individual hands-on work in the laboratory to conduct experiments and explore the use of electronic equipment. Every week students have three one-hour lectures and regular hands-on work in the electronics lab.
These issues led the instructor of ENSC 125 to explore the option of offering a Web-based version of the course as an alternative to the physical lab through virtual instrumentation in a "online lab". The concept of "virtual labs", where students analyze, simulate, and test basic electronic circuits, promises to enhance the course and to reach additional off-campus students. Collaborative tasks should foster the development of teamwork practices, a needed skill for a professional engineer. The software used for the delivery is Virtual-U, developed at Simon Fraser University.
The Virtual-U Web-based conferencing system
Virtual-U is a World Wide Web-based application customized for the design, delivery, and enhancement of post-secondary education. The main goal is to provide a flexible framework to support advanced pedagogies based on principles of active learning, collaboration, multiple perspectives, and knowledge building (Harasim, Calvert, & Groeneboer, 1996).
Virtual-U operates on an Internet network browser and offers asynchronous communication features to allow participants to contribute at their most convenient time, overcoming constraints of time and distance. Virtual-U has the core functionality of a computer conferencing system (VGroups) for asynchronous delivery and has tools to facilitate the instructor's task: Course Structuring Tool, GradeBook, and System Administration Tools.
The Course Structuring tool allows educators to design complete courses and put them online. The course template that is created includes instructor's information such as office hours and email address, course syllabus and timetable, activities such as readings, assignments and tests.
The VGroups conferencing system allows the instructor to create conferences or sub-conferences, to define the subject, structure and participants for each conference, and allow students to take on roles as moderators, participants or observers, and to insert multimedia elements such as video and animation into messages.
The GradeBook manages students' grades for each course delivered with Virtual-U. When a course is submitted, a GradeBook database is automatically created with a class list of students and all of the assignments and tests to be completed during the term. Grades can be entered and edited. The GradeBook displays customizable colour charts of student and class performance, supports quantitative and qualitative grades, and encryption security to protect sensitive information.
The System Administration Tools assist system administrators in installing and maintaining the Virtual-U Education System for functions such as creating and maintaining accounts, defining access privileges, creating courses, keeping usage statistics. As Virtual-U runs on the Web it works with plugins and home pages that enhance its functionality.
The goal of the Virtual-U software is to enable educational practices for knowledge building through group work, the support of the instructor and peers, and active individual work.
Engineering Science 125: Introductory Electronics
ENSC125 is an introduction to electronics and covers topics such as properties of electrical circuits, frequency response, properties of LCR circuits, diodes, transistors, and fundamentals of electrical measurements of non electrical quantities, transduction theory, and instrumentation. ENSC 125 is a prerequisite for course ENSC 222-5, Electronic Design I.
ENSC125 is offered to both transfer and first year students who enter the Department's program. Students take ENSC 125 in their first year to have an introduction to analysis and design, as well as a stronger preparation for the first co-op work term. Students are given 24-hour lab access to pursue projects that are more open-ended and less structured than in traditional schools.
Learning with virtual instrumentation and collaboration: Pedagogy and activities
The combination of self-directed learning, peer collaboration, lab experimentation, and instructors' support is a powerful model that relies on "learning by doing" with an active hands-on component. This model has been named "situated learning" as the context is identified as playing a major role in the knowledge building process.
Brown, Collins & Duguid (1989) developed the concept of situated learning to emphasize the role of the context, the activity, and the culture in the production of knowledge:
For centuries, the epistemology that has guided educational practice has concentrated primarily on conceptual representations and made its relation to objects in the world problematic by assuming that, cognitively, representation is prior to all else. A theory of situated cognition suggests that activity and perception are importantly and epistemologically prior - at a conceptual level - to conceptualization and that it is on them that more attention needs to be focused. An epistemology that begins with activity and perception, which are first and foremost embedded in the world, may simply bypass the classical problem of reference - of mediating conceptual representations (p. 41).
The collaborative social interaction that takes place in the appropriate context promotes learning.
Learning, both outside and inside school, advances through collaborative social interaction and the social construction of knowledge... Throughout most of their lives people learn and work collaboratively, not individually, as they are asked to do in many schools (p. 40).
The new design for ENS 125 supports the concept of situated learning which is implemented through exploration and experimentation in "virtual labs' where students explore the same concepts and experiments through "virtual instrumentation" and share results with peers and the instructor.
Students use a collaborative approach and rely on peers to obtain support via computer conferencing and email. Through the system students can access peers, electronics experts, or search through various remote databases for information.
The additional software packages, Electronics Workbench and MathCad, allow students to complete their assignments in virtual experiments.
Course Design
Students taking ENSC 125 have the following requirements: they need access to a computer that runs Netscape 2.0 or above, a minimal of 14.400 modem, access to Netscape, and an Internet account. In addition they need the Electronics Workbench and MathCad software packages.
ENSC 125 Online is composed of 14 conferences, each with a specific purpose: Social, Team, MathCad, EWB, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8, Week 9, Week 10, and Exam.
Each session was named after the week (Week 6, 7, 8, etc) and each Week conference has a Theory and a Practice subconferences. Studens use FTP to post their assignment files (EWB and MathCad) to a site where they are downloaded by peers and the instructor.
Students are expected to logon many times a week to contribute to the discussion, to respond to questions, and to pose new questions. The final exam will be conducted face-to-face and proctors will be used for those students who can not come to campus.
Here is a sample taken from Week 6, containing the initial message from the instructor for discussion in the Theory subconference and the initial message for the Practice subconference with information about the assignment.
Theory:
Chapters 1 covers the basics of the circuit elements we will be dealing with (R, L and C), current and voltage sources, and energy. Chapter 2 outlines several methods for analyzing circuits and solving for circuit currents and voltages. You should be able to apply any of the following methods to solve for circuit currents and voltages:
(i) Loop - current method, (ii) Node - voltage method, (iii) Thevenin Equivalent (very important), (iv) Norton Equivalent (we don't use this as much), (v) Superposition
Don't worry too much about the analysis of non-linear networks although you will revisit this topic in detail in future courses.
The assigned problems are in the study guide. Work out as many as you can on paper and then prepare your assigned problem using MathCad and/or Electronics WorkBench. The sample problem I gave you should give you an idea of what I mean by a formal solution presentation.
In some of the problems it simply asks you to derive an expression but MathCad is geared towards finding numerical solutions. I suggest you derive the expressions and then illustrate the solution with an example. For example AP1-3 essentially asks you to derive an expression for the power from the voltage and current. I would illustrate this by sketching the current, voltage and power using the defined current signal.
Problem AP1-6 asks you to derive more expressions and I would define suitable values for Rr, c, and k to show how one might apply this problem to designing a fuse that blows at 2 A, for example. Preparation of a formal solution always take a bit more time but allows us to communicate more effectively so we can discuss the problem together (don't worry, you can still do your problems on paper during tests and exams).
Practice:
I'm assuming you all had a chance to get your radio kit and are thinking about the "headphone" problem: (i) How do earphones work?, (ii) How do headphones (loud speakers) work?, (iii) How do you model headphones? (iv) How should you connect them to your amplifier?
Each one of you should provide at least one "original" thought on the subject for the lab study as well as any rebuttals you feel are appropriate for any submissions you support or disagree with.
As far as Lab #1 is concerned you should follow the lab and perform the experiment here or using EWB. Remember to consider the measurement effects of the DMM when it is introduced into the circuit. One very important thing I forgot to mention was how to deal with experimental error.
Basically you need to validate your experimental results against expected results within bounds of uncertainty. For example Lab Familiarization (p. 13) requires you to verify Ohm' Law. First you need to predict the current which should flow through the resistor and then compare it to the measured current. But does it have to match exactly? NO. In fact all you have to do is demonstrate that the bounds on the expected current overlap the bounds on the measured current. What do I mean by bounds? Well, there is uncertainty associated with any measurement. For example the accuracy of the DMM for measuring voltages is +/- 0.1% + 1 digit. If the DMM reading is 0.999 V then the error is +/- 0.002 V (the 0.1% contributes 0.001 V and the 1 digit uncertainty in the display means it could be off by another 0.001 V). So the voltage could be anywhere between 1.001 V and 0.997 V (the max and min). We could find the same bounds by measuring the resistor (+/- 0.2% + 1 digit) and current (+/- 0.3% + 1 digit). Therefore when we calculate the range of expected current, it is bounded by Imax=Vmax/Rmin and Imin=Vmin/Rmax. We then check for overlap of this "expected range" with the range resulting from the uncertainty in the actual current measurement. If there is overlap then we have validated the experiment. If not we need to find out why not.
Try to post at least 1 insight that you have to offer from the lab experiment.
The Virtual Experiment
The new design provides students with the tools to complete assignments in a "virtual lab" environment using software for circuit analysis (MathCAD), circuit simulation (Electronics Workbench) and circuit prototyping (LabLink). Using LabLink the student constructs the circuit and tests it using "virtual instrumentation" running on the host computer that is connected to the real circuit through a hardware applications interface. Students are encouraged, at the end of the course, to build the circuits and test them using real equipment found on a traditional electronics lab bench.
Collaborative Tasks
Some of the tasks given to students are based on collaboration and information sharing as students share assignments, insights into their weekly experiments, and pose questions to their peers based on the weekly virtual lab experiment.
Here is an example of how a collaborative task is assigned to students on the 6th week of class:
You will receive 4% this week if you do the following:
(i) Successfully complete your assigned question in MathCad and upload it to the ftp site (ftp://142.58.000.000/Pub), for 1%.
(ii) Critique one of your peer's solutions in the "Theory" subconference in the appropriate Week AND pose 1 question or comment or reply each week, for 1%
(iii) Provide a discussion topic or comment or reply in the "Practice" subconference each week (pertaining to either the lab or lab study),
for 1%.
(iv) Pose a sample question for the final exam in the EXAM subconference.
You can ftp the MathCad or EWB file to the appropriate MCAD or EWB folder as well. I will pick the best question each week and use it on the final exam, for 1%.
Implications for Design and Research
This new instructional and delivery model raises new questions which need to be investigated: how virtual learning compares with the traditional face-to-face classroom learning, what are the implications of using "virtual instrumentation" compared to instrumentation in the campus lab, what is the role of peer learning and collaboration in virtual environments, and what are the best instructional designs to explore the potentials of this new technology for learning.
REFERENCES
Brown, J., Collins, A. & Duguid, P. "Situated Cognition and the Culture of Learning", in Educational Researcher, 18(1), 1989, pp. 32-42.
Collings, T. (1994) "Basic Electronics Engineering". Burnaby: Department of Engineering Science, Simon Fraser University.
Harasim, L., Calvert, T. , Groeneboer, C. (1996) Virtual-U: A Web-Based Environment to Support Collaborative Learning and Knowledge Building in Post Secondary Courses.
Harasim, L. & Teles, L. (1994) "Interactive Group Learning Using Communication Networks". In Stahmer, A., Van den Brande, L., and Rivet, T. (Eds). The Canada-European Union Workshop on New Media Learning Technologies: Perspectives on Developing an International Collaborative Learning for Flexible and Distance Learning. Ottawa: The Canada-European Union Workshop, Industry Canada.
Hiltz, R. (1994) "The Virtual Classroom". Norwood, NJ: Ablex Publishing.
Teles, L. & Laks, A. (1993) "The Virtual Interactive Environment for Workgroups: A Broadband Educational Application ". Proceedings of the I Multimedia Communications 93, University of British Columbia, November 1993.
Dr. Lucio Teles is Co-Director, University Centre for Network Learning, Simon Fraser University. He has conducted research on the use of computer mediated-communication to enhance classroom learning and for course delivery. His most recent publication is a book co-authored with L. Harasim, R. Hiltz, & M.Turoff entitled Learning Networks: A Field Guide to Learning and Teaching Online, Cambridge:MIT Press.
Email address: teles@sfu.ca
Dr. Tim Collings is a professor in the Department of Engineering Sciences, Simon Fraser University. In addition to teaching graduate and undergraduate courses he also conducts various research and development projects. Currently he is involved in the design and development of a DSP microchip to facilitate selection and control of TV channels.
Email address: collings@cs.sfu.ca