NIZAR, Al-Holou
Electrical and Computer Engineering Dept., University of Detroit Mercy, 4001 W. McNichols Rd., Detroit, MI 48219-0900, alholoun@udmercy.edu
Abstract: The recent advances in computer technologies including faster CPUs, less expensive RAM, CD-ROM delivery, international standards for still and moving pictures compressions (JPEG and MPEG) and full-motion digital video, have led educators to investigate alternative ways to attract and educate students, particularly non-traditional programs. Moreover, American industry has initiated cooperation with universities to build ”modular” educational course elements that allow employees to expand their knowledge, and thus increase the company’s competitive edge. The challenge is two parts: First, bring ”multimedia”-enhanced (the computer-enabled combination of text, video, and sound) courseware into the workplace as well as classroom. Second, interactively ”narrowcast” state-of-the-art lectures into the employees’ work place, home, and—ultimately—onto their desktop. In this paper, we discuss the development of a Computer-based Instruction in digital logic using Authorware Professional 3.5 for Windows.
Keywords: Computer-Based Instruction (CBI), Digital Circuits, Multimedia
Students have different learning styles and therefore can be classified as active, visual, inductive, sensor, and sequential [1-2]. Many studies have documented that traditional classroom teaching is not the best approach to teach college students [3-6]. Therefore, a new innovative teaching pedagogy is needed. As a result, educational institutions have started new approaches to enhance student learning [7-11]. These approaches can be classified as computer-based instruction (CBT), distance learning, and web-based delivery. Computer-based instruction, the topic of this paper, integrates text, graphics, audio, video, and animation.
Many multimedia tools exist to develop computer-based curriculum such as Authorware, Director, and Toolbook. Well-implemented multimedia curriculum is an effective tool in education, learning, and training especially technical education. Such curriculum is capable of holding students' attention, encouraging their involvement, and animating technical concepts with impressive result [12]. Combining text, graphics, audio and video clips, and animation in creating instructional materials help students visualize and understand difficult concepts [13]. Many terminologies exist to accommodate new directions in multimedia curriculum development. Terminology such as Computer-Based Training (CBT), Computer-Based Instruction (CBI), Computer-Based Education (CBE), Computer-Based Learning (CBL), and Computer-Assisted Instruction (CAI). The Institute of Electrical and Electronic Engineers (IEEE) is developing a standard for CBI to accommodate this trend [14]. This paper concentrates on the development of Computer Based Instruction (CBI) in digital logic.
CBI includes computer-enabled combination of on-screen text and images with digitized sound, voice, photographs, and full-motion video. It is self-paced as well as interactive. Other features included in CBI are a logical, changeable presentation flow of information based on sound instructional theory (computer-managed instruction, or CMI) as well as the tracking of the student progress through the instructional program, and recording of test results. This powerful combination of functionality may, over time, replace some aspects of traditional classroom learning. The development of CBI courses initially requires a large investment. However, this cost is typically absorbed in a couple of years. Corporations that regularly use CBI have typically saved millions of dollars of training costs. Corporate training is a big business today, reaching $48 billion annually [15]. CBI delivery minimizes the interruption of work schedules for both students as well as employee trainers, and eliminates the need to travel to school or training center sites. Students can initiate instruction according to individual schedules and convenience.
The Computer Based Instruction (CBI) curriculum is developed using Macromedia's Authorware 3.5 Professional for Windows (Macromedia, San Francisco, CA). Authorware is an object-oriented authoring tool that supports the incorporation of text, graphics, animation, audio, and video that are based on sound instructional systems design principles [16-17].
This project is funded by NSF through Greenfield Coalition (Grant #EEC-9221542). The Greenfield Coalition is a National Science Foundation supported partnership of six diverse educational institutions, five top manufacturing companies, an international member-based educational society, and an operational manufacturing/teaching enterprise. Greenfield Coalition for New Manufacturing Education is a National Science Foundation-supported partnership of six diverse educational institutions, five top manufacturing companies, an international member-based educational society, and an operational manufacturing/teaching enterprise. Greenfield is a new model for manufacturing education based on the combination of skill and deep engineering knowledge resulting from an integration of engineering practice and innovative pedagogy. The coalition is creating next-generation courseware designed to integrate training issues with educational foundations. This is being accomplished by combining theory and practice in an interdisciplinary, team-oriented environment anchored to a ”real world” production floor—the first delivery site, Focus:HOPE’s ”Center for Advanced Technologies.” The Greenfield courses are designed to be modular in nature, and thus offer an ideal educational environment for multimedia-based CBI delivery.
Digital concepts plays an important role in the modern technology. Moreover, it is not an easy subject for Engineering students, especially non-EE majors, to understand. Computer-based instructions will be used to make it more interesting, easy to understand, and intuitive. Animation has been used in every topic to illustrate most of the new concepts, starting from number system, Boolean algebra, and end with digital logic circuit design. That include Boolean algebra to give the students the background of this module. The second thing is to change the ideas form the theory to electricity in logic gates section. After that we introduce the combinational logic and sequential logic gates. Each topic is supported by a quick test to emphasize the concepts. Many real-world case studies with animation have been used in this module such as simple adder, control circuits, counters, storage, sequence detection, and clock divider. Based on this module, candidate will gain a good understanding of Boolean algebra, logic gates, combinational circuits, and sequential circuits.
The first topic, Boolean algebra, presents basic operations and theorems of binary number system such as commutative, associative laws, simplification theorems, and DeMorgrans’ laws. These theorem are introduces and supported by examples and animation to simplify and illustrate these concepts. Boolean algebra has been used to simplify any Boolean expression. Boolean Algebra simplification may lead to reduction in the number of gates needed to implement any logic function. Figure 1 shows a screen capture from CBI that illustrates the steps to simplify a Boolean expression.
Figure 1. Simplification of boolean algebra expression.
The second topic covers logic gates. The topic starts with AND, NOT, and OR logic gate symbols, truth tables, and their logical operations. Then it covers NAND, and NOR logic gates. Design of a half adder and a full adder were introduced as a simple combinational logic design problem. Animation is used to illustrates the relationship between the logic function and logic diagram as shown in Figure 2.
Figure 2. derivation of logic function from logic diagram
The third topic, combinational circuit design, that illustrates how to design logic circuit starting from the circuit description and ending with logic diagram. It includes also building half and full adder logic circuits supported with animation to emphasize the concept.
The fourth topic, sequential circuit, introduces flip-flops as the basic memory elements in sequential circuits. It covers different types of flip-flops such as SR latch, JK, D, and T flip flops. Also other topics such as edge-triggered and level-sensitive flip-flops are introduced. It starts with simple SR latch using 2 NAND gates and 2 OR gates. Then, we add two control gates to the basic building block of the SR latch to implement clocked flip-flops such as JK and T flip-flops. Animation is used to illustrate how the input changes will affect the output of every gate to set, reset, and store binary data in the flip-flop. The animation synchronizes the input/output changes with timing diagram. This animation is very helpful for students to understand complicated timing. Many design problems such as counter design, parallel storage, clock divider, and sequence detector, are discussed, analyzed, and illustrated by animation. Figure 3 shows the logic diagram of the sequence detector circuit.
Figure 3. Logic diagram of sequence detector
The last topic introduces some common logic circuits such as comparator, arithmetic unit, encoder, decoder, multiplexer, demultiplexer, and code converter.
The digital logic module, which is the last module in the Electroscience Curriculum is under development as a Computer-based Instruction (CBI). Authorware Professional 3.5 is being used as the Authoring tool on this development. CBI can offer an extremely efficient and cost-effective approach for both instructional development and delivery. Although ”up front” development time/cost is high, delivery economies include a single message deliverable in multiple and customizable ways, thus allowing minimal interruption of work schedules for both students as well as employee training, and eliminating or greatly reducing the need to travel to school or training center sites. But perhaps most important, it gives instructors the ability to develop encapsulated elements of their courses ”off line,” that is, in their offices instead of traveling to different sites and repeating the same information. The curriculum has been offered to Focus:Hope candidates. The candidates like the CBI modules and did not like using textbook.
The work based upon work supported by National Science Foundation through Greenfield Coalition (Grant #EEC-9221542). The author would like to acknowledge the students: Imad Abdellatif, Faroog Ibrahim, and Khalid daghameen who worked on this project.