Algorithm animation is a form of program visualization that is concerned with dynamic and interactive graphical displays of a program's fundamental operations. This paper describes the Zeus algorithm animation system. Zeus is noteworthy for its use of objects, strong-typing, and parallelism. Also of interest is how the system can be used for building multi-view editors. Review by Jim Meehan In many applications, it is at least as important to observe a program's progress as it is to obtain a final result, if indeed there is any. The Zeus system described in this paper provides support for watching and hearing a program in action, through several different views. The programmer animating an application provides a description of the application's fundamental operations, called "interesting events." Whenever an interesting event occurs, each view updates its visual or aural display appropriately. The Zeus system exploits Modula's object-inheritance, lightweight threads, and compile-time ...

As algorithm animation systems become more widely available and easy to use, instructors must decide whether to utilize these systems to assist their teaching. Although these systems have generated excitement and interest in both teachers and students, little empirical evidence exists to promote their use. This article describes a study involving the use of algorithm animations in classroom and laboratory settings. Results indicated that allowing students to create their own examples in a laboratory session led to higher accuracy on the post-test examination of understanding of the algorithm as compared to students who viewed prepared examples or no laboratory examples.

This report describes a variety of 3D interactive graphics techniques for visualizing programs. The third dimension provides an extra degree of freedom for conveying information, much as color adds to black-and-white images, animation adds to static images, and sound adds to silent animations. The examples in this report illustrate three fundamental uses of 3D: for providing additional information about objects that are intrinsically two-dimensional, for uniting multiple views, and for capturing a history of execution. The application of dynamic three-dimensional graphics to program visualization is largely unexplored. A videotape of these animations is available.

We describe the design and use of AUDIOGRAPH- a tool for investigating the use of music in the communication of graphical information to blind and partially sighted users. This paper examines the use of the system to communicate complex diagrams and gives some examples of user output. Performance is not as good as expected and it is postulated that context will play an important part in the perception of diagrams communicated using music. A set of experiments are reported which indicate that context does indeed seem to play an important role in assisting meaningful understanding of the diagrams communicated. The implications for using music in auditory interface design are discussed.

SeeSys TM is a system embodying a technique for visualizing statis-tics associated with code that is divided hierarchically into subsystems, directories, and les. This technique can display therelative sizes of the components in the system, the relative stability of the components, the location of new functionality, and the location of error-prone code with many bug xes. Using animation, it can display the historical evolution of the code. Applying this technique, the source code from amulti-million line production software product is visualized.

We have a project currently underway that attempts to use 3D workstations to provide insight into programs, their structure and their execution, through the use of a variety of user-definable displays. We offer a variety of different presentation styles and utilize a variety of different layout methods and heuristics. This paper describes the underlying engine that we have developed to support this range of presentations.

In this paper we present LEONARDO, an integrated environment for software visualization that allows the user to edit, compile, execute, and animate general-purpose C programs.

In this paper we propose a new model, called Mocha, for providing algorithm animation over the World Wide Web. Mocha is a distributed model with a client-server architecture that optimally partitions the software components of a typical algorithm animation system, and leverages the power of the Java language, an emerging standard for distributing interactive platform-independent applications across the Web. Mocha provides high levels of security, protects the algorithm code, places a light communication load on the Internet, and allows users with limited computing resources to access animations of computationally expensive algorithms. The user interface combines fast responsiveness and user friendliness with the powerful authoring capabilities of hypertext narratives. We describe the architecture of Mocha and show its advantages over previous methods for algorithm animation over the Internet. We also present a prototype of an animation system for geometric algorithms that can be access...

AURALIZATION OF DOCUMENT STRUCTURE Steve Portigal Advisor: University of Guelph, 1994 Professor T. Carey An experiment compared the effectiveness of auditory, visual, and combination cues to convey document structure. Subjects demonstrated an equivalent level of understanding of the document structure and its content with either a combination cue or a visual cue. Subjects required more time to answer questions in the combination condition than in the visual condition. This suggests a greater cognitive effort is required. A sound-only condition has the poorest performance both in response time and in the subject's answers to questions about the document's structure and its content. Subjects were grouped based on whether or not they replayed sounds as a retention tactic. Subjects who replayed sounds did better than subjects who did not. These results contribute to our understanding of potential uses of sound in user interfaces. The specific cues used here for this particular task do not ...

In the field of auditory display relatively little work has focused on the use of sound to aid program debugging. This paper describes CAITLIN 1 a pre-processor for Turbo Pascal programs that musically auralises programs with a view to assisting novice programmers with locating errors in their code. A discussion follows of an experiment which showed that programmers could use the musical feedback to visualise and describe program structure. Conclusions and a discussion of future work are then given.