There have been great advances in communication and networking in recent times. It is necessary to take advantage of this information infrastructure for the purpose of developing an engineering education system, but the networking system was expensive or hard to develop. The current international networking is converging to the use of the World Wide Web system. It has become a new standard for global network communication. But there are not a great number of applications which take full advantage of this environment.

In this paper, an interactive education system for engineering education using the World Wide Web will be presented. This can be used as a supplementary kit for engineering education. Two independent method of using network will be presented. The first is about interactive education tools, and the second is about an evaluation tool. The system is developed using JAVA and can be accessed using Web browsers.

INTRODUCTION

The educational methods have been changed in many respect with the advent of various kind of media. Unlike the old time's monotonous teaching, educators are using computers to convey their knowledge to the educatee. These media are animations, sounds, pictures, and many interactive computer programs.

There are two important things in education: interaction and evaluation. Education should be performed in interactive communicative environment, and also should be evaluated appropriately. The latter is important not only to scale the capability and understanding of the educatee but also as an index for lecture's achievement. Their is something general in engineering education, and this generality can be utilized for each aspect. For the interactive communication aspect, an engineering design experiment plays an important role. Educatee understand engineering concepts better by trying several different parameters in the models taught in the class. It is very useful to have an automatic interactive parameter design program. It will save time for conceptual understanding. In the evaluation aspect, the engineering problem solving is mainly sets of problems with different parametric numbers. Most of the problem sets are composed of problems which test the understanding of some formulas. It is very useful to have automatic evaluator for engineering problems, which generates examination and grades. It will save educator's time for problem generating and grading.

These topics can be implemented using programs. In the past, the educator would write the programs for interactive education and distribute them to the educatees or present them in the class using a projector. This was the only possible way to do interactive education before the advent of Internet. For the problem evaluator, problem generating was possible to program. But it is not possible to give examinations on-line, and manage the examination results automatically.

There is a revolution in the world of the Internet, and theses limitations can be overcome. People are using the Internet to access the information they need. JAVA is a perfect programming language to implement these ideas. The advantage of JAVA programming is platform independence and its accessibility to wide range of people. The JAVA programs developed for the two aspects of engineering educations are presented individually in the main body of this paper.

USE OF JAVA FOR AN INTERACTIVE EDUCATION SYSTEM

Selection of the tool: JAVA

JAVA is the name of a programming language used for Internet application development. HTML includes applets written by JAVA, which is called from Web browsers like Netscape Navigator or Hot Java. JAVA provides most solutions for the problems related to the Internet. The advantage and features of JAVA are:

- It is an object oriented programming language. This provides environment where users only concentrate on the behavior of objects. JAVA provides solutions for the problem of code reuse which were relatively difficult in conventional procedural programs. With the source given, people can easily modify the part without many difficulties.

- It is very portable. JAVA program on a platform runs well in another platform. The same code of JAVA runs on the platforms like Window95, Macintosh, and Solaris workstations. A programmer can save time required to port a program to each different platforms. The program developed in this paper is run any platform mentioned above.

- It has very high performance. The multi-thread technique executes program fast and shares many tasks.

- It is very secure. JAVA has a multi-level security concept. It is resistant to outside hackers or intention to work on the host system. This also provides benefit of protecting your private student grade results or problem files.

- It provides network programming. People access JAVA applet using Netscape Navigator, or Hot Java Web browsers. Many people can use applets at the same time. It also provides URC connections, so a user can access URL site, mail site, and ftp site. It also can access a file system of a host ( This depends on web browsers, and there are some limitations).

The advantages from the above list clearly show the benefits of using JAVA for the interactive education system development. The packages developed are explained in the following sections individually. The interactive educational tool development will be presented first, and the engineering problem evaluator will be presented.

Development of Interactive Education Tool

Electrical machine is a hard subject for students. It need some conceptual intuition to understand the principals of each different machine. Furthermore, the implementation of the theory is the hardest part. Usually students don't have much chance to interactively play with concepts and design parameters, owing to the lack of materials and limitations of communication with an educator. Application of an interactive educational tool to this area will show some of the general applicability to the other engineering subjects. Interactive parametric design examples and phenomenal factor changing examples show how to make students understand the concepts easily. The interactive parametric design example is a program about commutator numbers and rectified voltage regulation of DC machine.

Figure 1. Commutator example. (commutator = 4, flux density = 1) down

The students are expected to understand how the commutator is positioned, and the fact that the increasing number of commutators improves the direct current quality. They can try to adjust the number of commutator number, magnetic flux, velocity etc. Figure 1 shows a case when only four commutators exist. Two sinusoidal waves are generated to show the voltage induced in each winding and the box right below it shows the voltage induced at the end terminal. Figure 2 shows that as the flux and the commutator number increase, the output terminal voltage increased and the wave has improved dc quality. Many design factors can be varied according to a user's command, and the result of different designs can be accessed immediately. It becomes very convenient and clear for students to understand new conceptual parametric variance. The interface is simple with a button menu. To change parameter, it needs only to type in the text area and click the button.

Figure 2. Commutator example. (commutator= 16, flux density = 2) up

Figure 3 shows the result of phenomenal factor changing examples for DC armature reaction. Magnetic fields exist in a DC machine. As the generator or motor action starts a current flow on the windings, magnetic fields are generated and interacts with the main fields. This reactive field generates many unexpected results in DC machine behavior. The main result is the shifting of neutral axis of the total fields. Students can identify this action by changing parameters. Figure 4 shows the result of larger armature current interacting with the main fields. The neutral axis is shifted more than the result of the figure 3.

Figure 3. Armature reaction example. (small current in armature) up

Figure 4. Armature reaction example. (large current in armature) up

The examples show that the possibility of using JAVA for an instructional aid. The material can be used for supplementary teaching aids. Students can access the program any time they want and test the behavior of design parameters or phenomenal parameters.

Development of Engineering Evaluation Tools

Evaluation of engineering education largely oriented toward the usage of formulas. An example of a common electrical engineering problem is this: " If the current is 2 Ampere and the resistor is 10 Ohm, calculate the voltage generated at the terminal of the resistor". This is Ohm's law, and the result is 20 Volts: 10 multiplied by 2. The evaluation system consists of a problem generating module and a grading module.

One possible solution for a problem generator is database approach. This randomly gets the required number of problems from a problem data bank. If this is to be used as a reasonable problem generator, there should be fairly large problem database. Even for a simple problem like Ohm's law, it is not reasonable to build a database with similar sets of parameters.

This problem can be partly solved by using different scheme for problem generation. For problems testing usage of the same formula, the problem generator automatically generates a problem with randomly generated parameters. For Ohm's law example, the current and the resistor values are determined by randomly generated numbers. For a problem testing for formula understanding, the same pattern with different parameters can be generated as required.

The benefit of using a scheme for random problem generation is saving time. It is not necessary to make large number of database for problem generation. With the connection of the automatic grader, the evaluating system provides more benefits. A student can take exam at convenient time on the network. Educator gives test as often as necessary without the burden of the problem generation and grading. This system is best used as a supplementary evaluation device. The recommendation is including oral tests several time during the education, so that the test result are not entirely dependent on the automatic education evaluation system.

The evaluator's view is shown in Figure 5. There are 20 answer buttons, a student identification number, and student name text fields. If a student clicks the "Start the test button, it automatically generates the problem. The generated problem is shown on the view terminal. After finishing the test, a student clicks "Finish the test. The test results are saved as a file in the host directory.

There is a security problem in reading and creating files on the Internet using JAVA. There is no problem using JAVA as an independent application when it is not linked with browsers. But when it is used as an applet and included in an HTML file, file access is limited. Other options are being considered at this point in time. Using mail for the test result collecting is one of the possible option.

METHODOLOGICAL ANALYSIS OF IMPLEMENTATION

The interactive educational tool is generally applicable to a wide scope of engineering problems. This presentation was done for electrical machines but it can easily be extended to the areas like electrical circuit teaching or other fields. Of course it would be difficult to develop a full electrical circuit design set or differential equation solver using JAVA. But the problem in education engineering starts from basic conceptual understanding difficulties.

The four large categories of electrical machines are DC machines, synchronous machines, induction machines, and transformers. To complete set of interactive educational tool for an electrical machine category, there are 7-8 topics appropriate to programming. In collecting the topics to program, the students played an important role. As a term project they were asked to write C programs for teaching aid for the class. The student were highly motivated group for this kind of project, because they had difficulties understanding relevant topics. The program doesn't have to be complicated for this kind of tutorial aid, and avoiding complicated program development is recommended. There are three more topics in DC machines appropriate for interactive education program development, and implementation of these will give more ideas for interactive education tool development. They are listed below:

Hysteresis curve trainer: The relationship between currents and flux induced is not proportional. The characteristic curve is called Hysteresis curve. As the currents changes sinusoidally, students can watch how magnetic flux is generated. The students can change the shape of the hysteresis curve, and watch what happens to flux generation.

Armature winding checker: Conductors are placed on an armature in the form of windings. With a slot number, the program can design how windings are placed on the armature. It can show how windings are connected from a side view.

Velocity control verifier: According to parameters of resistance and applied voltage, the velocity characteristic changes. This causes changes in the operation point. The unit returns the operation condition and a changes characteristic line.

Implementation using JAVA is additional difficulty for beginners. But the object oriented approach helps for the people who just want to make small changes to original programs. Actually a student with C++ programming background only takes 1 or 2 days to implement the C program as a JAVA applet. Of course, there should be enough directive discussion about the sample source of the original JAVA applet source code on which the student is going to add their application.

FURTHER STUDIES

For interactive education tool, currently DC machine modules are completed. The problem evaluator works on the database level right now. More work needs to be done to fully implement the capabilities mentioned above. Parsing will be a key technique to implement the ideas of evaluator.

REFERENCES

1. Paul M. Tyma, Gbriel, and Troy Downing, "JAVA PRLMER PLUS", The Waite Group, Inc 1996.
2. K.C. Hopson and Stephen E. Ingram,"Developing Professional JAVA APPLETS", Sams.net Publishing, 1996, Chapter 1.
3. H. Bungay, M. W. Kuchinski, "The world wide web for teaching chemical engineering ", ChE Division of ASEE, summer 1995
4. The Joint Task Force on Engineering Education Assessment, "A Framework for the Assessment of Engineering Education", ASEE Assessment White Paper, June, 1996.

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