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WWW Technology in Courses in Computer Graphics and Scientific Visualization G. Scott Owen

Abstract

The rapid emergence of the World Wide Web and its associated tools has provided educators with an opportunity to incorporate this technology into their courses. The author has developed a Web based system for class presentation and class text that includes HTML and PDF documents, VRML worlds, and Java applets. His students use HTML for project reports and examinations. In addition, the computer graphics students learn VRML in the first course. This has enabled the paperless class to become a reality.

 

Introduction

Educational institutions need to take advantage of World Wide Web (WWW) technology to deliver instructional materials. The state of Georgia and the entire USA is in the process of enhancing the Internet to create an "Information Superhighway". The goal is the high speed delivery of information and entertainment into homes, offices and schools. We as academics need to leverage this effort by creating multimedia instructional materials that can be delivered, via this high speed network, directly to students. This material will supplement, and partially replace traditional classroom lectures. Eventually an entire course can be delivered in this fashion with only occasional scheduled class meetings. The teacher will interact with students via electronic conferencing, and students will work together collaboratively on problem solving as a way to make their understanding of the material more real and relevant.

 

In this paper I will discuss how the use of HTML, VRML, and other Web technologies have been integrated into our graphics and visualization courses [OWEN95]. I will not discuss searching the Web for external material, although that is done in the courses, but will focus on how HTML documents are used for in-class presentation, as the text in the course, and for student assignments.

 

Background and Development of HyperGraph

In the past several years I have been moving from a conventional lecture course to a hypermedia based course to an Internet based hypermedia course, both in instructional delivery and in student assignments. I primarily teach three different courses: Computer Graphics, Advanced Computer Graphics, and Data Visualization. The primary texts in the courses are the hypermedia systems HyperGraph and HyperVis.

 

The origin of HyperGraph was in a set of notes that had been developed for my computer graphics classes. For an overview of the material taught in these courses see [OWEN91a], [OWEN92b], and [OWEN94]. These notes were extended and used for the National Science Foundation Faculty (NSF) Enhancement Workshops on Computer Graphics in August, 1990 (NSF Grant #USE-8954402) [OWEN91b]. In our computer graphics courses I have used a variety of texts and found that my notes were becoming incompatible with any single text and the students were using the outside texts less and less. With support from the ACM SIGGRAPH Education Committee plus residual NSF funds, these notes were converted to the initial version of HyperGraph [OWEN92a]. I decided to use HyperGraph as the primary reference for teaching the computer graphics classes, starting winter quarter, 1993. HyperGraph was also used in Faculty Enhancement Workshops on Computer Graphics held at GSU in August, 1993 and 1994 (supported by the ACM SIGGRAPH Education Committee and the NSF (Grant #DUE-9255489)).

 

There are several considerations when developing a hypermedia system. One of these is portability and longevity. It requires a huge amount of work and effort to create a substantial system. Thus, one wants it to be able to adjust to changing technology and be portable among different platforms. Of course, one consideration about using a proprietary system is that the company that supports the software may disappear. When I first started developing HyperGraph there was no widespread public domain system so I had to choose a proprietary system.

 

The hypermedia authoring system used was Guide [GUID93]. Guide is a window based system wherein one or more windows can be opened and each window can be scrolled and may contain an entire file of text and graphics. The windows can be dynamically resized and so are easy to port to systems with different screen resolutions. Although HyperGraph contains different media types, there is a large amount of text, just as there is in conventional computer graphics textbooks. Thus, it required an authoring system that was very capable and flexible in the handling of hypertext. Guide was originally designed for hypertext and so has excellent text handling facilities with several different types of links or buttons for text.. It also has easy ways to launch external commands, which can display images, an animation, video, or interactive programs.

 

The Guide system also seemed to address the portability issue in that it ran on both IBM PCs and Macintoshs and a version was being developed for UNIX. Unfortunately, the company stopped development on both the Macintosh and UNIX variations and so the newer versions run only on DOS/Windows platforms. Also, authoring documents in Guide required the purchase of the authoring system, about $300 educational price, which meant that other faculty could not easily contribute to the development, and that students could not create their own hypermedia documents or modify HyperGraph.

 

After the WWW and HTML appeared, in 1993, I decided to start using this system. As previously discussed, the WWW became an international phenomenon by mid-1994; it was clear that HTML had become the defacto world standard for hypermedia documents and that this was an important technology that our students should learn. There are some problems in the current version of HTML, e.g., no mathematical symbols, and its text handling is not as flexible as that of Guide. But new improvements are being constantly made so these drawbacks should disappear. We are investigating the use of the Adobe Acrobat PDF system to address some of the above formatting issues.

 

Use of HyperGraph for Class Presentation

Because of its origin as a set of notes, the initial version of HyperGraph was organised as a book with a table of contents and links to the different chapters. While this view has been preserved and is still available to the students, the information space has been restructured in terms of a set of conceptual maps, represented as directed graphs, that cover the topics in computer graphics.

 

The student now has the option of moving through the set of conceptual maps until they arrive at a specific information node consisting of text, graphics, and interactive programs. Some of the interactive demonstration programs were written at GSU and some are from external sources. The ACM SIGGRAPH Education Committee Computer Graphics Courseware Repository (CGCR) is housed at GSU and we incorporated programs from there, such as the set of interactive demonstration programs written by Lt. Col. Dino Schweitzer of the U.S. Air Force Academy. Many of the programs were initially written for a DOS environment and we converted them to the Microsoft Windows environment. We are now converting some of these programs to Java so they will run over the Web.

 

Student Creation of HTML Documents

Since most Web/HTML tools are free, this meant that I could integrate HTML into my courses for student use. I started with the Computer Graphics course in the summer of 1994. In our upper division courses, taken by both undergraduates and graduate students, the graduate students must do a special project that goes beyond the undergraduate assignments. In the first Computer Graphics course [OWEN94] the students write their own ray tracing programs and also create images using the Pixar Renderman package. The special project of the graduate students was to create an HTML document which described their projects for the course. For each project they would describe the input data file, the characteristics of the output image, and then show the image. They turned this in as a set of HTML files plus the associated images.

 

This experiment was successful so the next quarter (Fall, 1994) in my Data Visualization course this was generalized to all of the students, both undergraduate and graduate. In this course the students do a set of projects, using the package IRIS Explorer, on Silicon Graphics Workstations. The projects are done by teams of students who then produce a report, consisting of images and text, on each project. All project reports were done as hypermedia documents in HTML format. The teams placed their reports on one of the workstations where I graded them. The student projects were accessible for all the students to view, so that they could learn from each other. The quality of the HTML documents improved during the course as the students read the other teams' documents and we critiqued them in class.

 

In these courses I sometimes give take home midterm and final examinations, so the students did these as HTML documents. I created a directory on a workstation for them to submit their examinations. Each student created their own subdirectory, placed their examination consisting of documents and images in the subdirectory, and then changed ownership of the directory and files to me. This way students could not read each others examinations. Since all assignments were sent as e-mail messages to the class this was a truly paperless course, except for the Syllabus, which legally must be on paper.

 

Effectiveness

There are three areas of effectiveness that I will address. The first is the effectiveness of using HyperGraph in the classroom, second is the effectiveness of using HyperGraph as the primary text in the course, and third is the effectiveness of having the students create their own hypermedia documents using HTML.

 

Classroom Effectiveness

At this point, it would be extremely difficult to teach my courses without HyperGraph and/or HyperVis. Computer Graphics and Data Visualization are both highly visual disciplines. It is extremely effective to be able to discuss an algorithm or technique using images as aids and then show the resulting image or animation. The students, both in written comments and informal discussions have stated that this has been very effective.

 

There are some improvements that need to be made, however. Some of these are technological and require better computer equipment. In showing the graphics images, it would be much better if the images could be shown in "true colour", i.e., at a colour resolution of 24 bits per pixel, rather than be restricted to the current 8-bits per pixel. This restriction causes colour artefacts to appear that hamper the interpretation of the images. Since many of the images are large, faster cpus, disks, and video cards would improve the speed of the presentation. Of course, this is even more true for the animations and digital video.

 

One must be careful in such a presentation to not just show students large amounts of text. This is a potential problem with HyperGraph since it is designed to replace a conventional textbook. So I use an overhead projection system to supplement HyperGraph. A better solution would be to use a tablet and write the notes directly on the screen.

 

Text Effectiveness

Generally the students have liked using HyperGraph as a text. All of the students, with one or two exceptions per class, have their own home systems that are capable of running HyperGraph. While some parts of it still need to be supplemented by conventional texts, as it evolves the goal is that it will be sufficient in itself. Many students do not purchase the supplemental texts but use only HyperGraph.

 

Student Creation of Hypermedia Documents

The students have responded very favourably to this aspect of the course. They know that by creating these documents and learning this technology, they are gaining valuable experience. It is also more fun for them. In the team reports, the students customised their documents and each team member had their own home page, with pictures of themselves, significant others, children, etc. This helped in building team spirit and helped engender a friendly competitiveness between the teams.

 

A danger in incorporating any new technology, especially in having students create their own hypermedia reports, is that the students will be so enthralled with the technology that they will focus on the glitz aspects and slight the content. I was very careful to avoid this and made sure the students knew that while the design and appearance of the reports or examinations were taken into consideration, the major part of the grade was based on the actual content. The quality of the reports and examinations has actually improved over previous paper based ones since the students can easily incorporate drawings and external images to illustrate their points.

 

Teaching VRML

In the Winter, 1996 Computer Graphics course, we switched from Renderman to the Virtual Reality Modeling Language (VRML). VRML is similar to Renderman in that the student can create a text file that describes the scene, and then input the text file to a VRML Browser that renders the scene. In the workshop I will describe how VRML was used in the course, resources to support VRML, the problems encountered, the student reaction to the use of VRML, and suggestions for the use of VRML in this and other courses [OWEN96].

 

Conclusion

In the last year, I have incorporated Web/HTML technology into my courses, for class presentation, for creation of a teaching text, for student created documents, including examinations, and for searching the Web for information. The student response has been quite positive. It will now be my practice that for all written reports, the students will create them as HTML documents.

 

References

[OWEN91a] Owen, G. S., "A Two Quarter Computer Graphics Sequence", Computer Graphics, Vol. 25 Num. 3, July, 1991.

 

[OWEN91b] Owen, G. S. and Miller, V.A., "A Workshop on Computer Graphics for Undergraduate Faculty", Computer Graphics, Vol. 25, Num. 3, July, 1991.

 

[OWEN92b] Owen, G. S., "Teaching Computer Graphics Using Renderman", Proceedings of the Twenty-Third SIGCSE Technical Symposium on Computer Science Education. Kansas City, March, 1992.

 

[OWEN94] Owen, G.S., "Teaching Image Synthesis as a Physical Science", Computers & Graphics, Vol. 18, no. 3, pp. 305-308, May/June, 1994.

 

[OWEN95] G. S. Owen, "Integrating World Wide Web Technology into courses in Computer Graphics and Scientific Visualization" Computer Graphics, Vol. 29:3, pp. 12-15, August, 1995.

 

[OWEN96] G. S. Owen, "Using VRML in an Introductory Computer Graphics Course", IEEE Computer Graphics and Applications (In Press).

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