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.

This paper descN4 es JCAT, a web-based algorithm animation system. JCATc ombines the expressive power of web pages for publishing passive multimedia cD tent with a fullfledged

Software engineers use system visualization mainly in two domains: algorithm visualization and system visualization, and both of these are often animated. In this paper we provide a generic link between the specification and animation of complex object-oriented reactive systems, which constitute one of the most important and difficult classes of systems. The link and its methodology form a basis for communication between standard reactive specification tools and standard animation tools. Reactive Animation can be used in a wide range of applications: computer games, navigation and traffic systems, interactive scientific visualization. Reactive Animation helps make the programming of such applications more reliable, expeditious and natural to observe and comprehend. We illustrate two examples: a complex biological model of thymic T-cell behavior and a traffic simulation.

We describe the implementation of a new system, called Mocha, for providing algorithm animation over the World Wide Web. Mocha is a distributed system 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 We have implemented a prototype of an animation system called Mocha that can be accessed by any user with a WWW browser supporting Java (currently Netscape 2.0 and HotJava) at URL http://www.cs.brown.edu/people/jib/Mocha.html. In this paper, we discuss in detail the implementation of Mocha. A companion paper [1] describes the model underlying the architecture and design of Mocha, provides a comparison between this model and previous ones, and presents an application to the animation of geometric algorithms. Design Goals Our design goals are derived from the comp...

Diagrams and illustrations are frequently used to help explain mathematical concepts. Stu-dents often create them with pencil and paper as an intuitive aid in visualizing relationships among variables, constants, and functions, and use them as a guide in writing the appro-priate mathematics to solve the problem. However, such static diagrams generally assist only in the initial formulation of the required mathematics, not in “debugging ” or problem analysis. This can be a severe limitation, even for simple problems with a natural mapping to the temporal dimension or problems with complex spatial relationships. To overcome these limitations we present mathematical sketching, a novel, pen-based, gestural interaction paradigm for mathematics problem solving. Mathematical sketching de-rives from the familiar pencil-and-paper process of drawing supporting diagrams to facilitate the formulation of mathematical expressions; however, with mathematical sketching, users can also leverage their physical intuition by watching their hand-drawn diagrams animate in response to continuous or discrete parameter changes in their written formulas. Diagram animation is driven by implicit associations that are inferred, either automatically or with gestural guidance, from mathematical expressions, diagram labels and drawing elements. We describe

When working with computer programs, either in an educational or industrial context, there is often a need to describe a program and its behaviour either to a tutor, student or colleague. Software Visualization (SV) uses techniques such as graphics and animation for describing a program or its algorithm. Software Visualizations are tied to a particular place (the machine on which it runs) and time (when the person willing to demonstrate and the person wishing to view are available), restricting their usefulness. Our solution to the above problem, the Internet Software Visualization Lab (ISVL), allows demonstrations to be staged over the web, providing a rich synchronous and asynchronous communication medium. We are currently testing a system created in ISVL on a Master's Programming course. 1: Introduction Software Visualization (SV) systems have been used to aid in computer science teaching and locating program bugs with varying degrees of success over a number of years (see [13]). S...

In this paper we present GeomNet, a system for performing distributed geometric computing over the Internet. We also provide several examples of actual geometric algorithms that our system already supports. Application domains for GeomNet include collaborative research and distance education.

We present a distributed algorithm animation system called Catai (for Concurrent Algorithms and data Types Animation over the Internet). Among the features of this system are a low effort required for animating algorithmic code, and the possibility of embedding animation clients in standard Java-enabled Web browsers. We believe this to be a good compromise between two different viewpoints: the programmer's perspective, which typically includes the goal of animating efficiently and unobtrusively a given algorithmic code, and the user's perspective, which can benefit from interactive, easy-to-use, distributed and cooperative interfaces. 1 Introduction Algorithm animation is a form of software visualization that uses interactive graphics to enhance the presentation, development and understanding of computer programs. Systems for algorithm animation have matured significantly in the last decade [2, 3, 6, 8, 9, 28, 29, 30], perhaps due to their relevance in many areas, including computer s...

A set of spatial index JAVA TM applets is described that enable users on the worldwide web to experiment with a number of variants of the quadtree spatial data structure for different spatial data types, and, most importantly, enable them to see in an animated manner how a number of basic search operations are executed for them. The spatial data types are points, line segments, and rectangles. The search operations are finding nearest neighbors from an object of arbitrary type and shape, and retrieving all objects that overlap an object of arbitrary type and shape or are within a given distance of an object of arbitrary type and shape. The nearest neighbor and within queries retrieve their results in the order of their distance from the given query object. The representations and algorithms are visualized and animated in a consistent manner using the same primitives so that the differences between the effects of the representations can be easily understood. The applets can be found

this paper we propose a new