Software visualization is the use of interactive computer graphics, typography, graphic design, animation, and cinematography to enhance the interface between the software engineer or the computer science student and their programs. Although several taxonomies of software visualization have been proposed, they use few dimensions and do not span the space of important distinctions between systems. We attempt to fill this gap in the literature by proposing a novel and systematic taxonomy of six areas making up thirty characteristic features of software visualization technology. The taxonomy is presented and illustrated in terms of its application to seven systems of historic importance and technical interest.

Current interactive user interface construction tools are often more of a hindrance than a benefit during the early stages of user interface design. These tools take too much time to use and force designers to specify more of the design details than they wish at this early stage. Most interface designers, especially those who have a background in graphic design, prefer to sketch early interface ideas on paper or on a whiteboard. We are developing an interactive tool called SILK that allows designers to quickly sketch an interface using an electronic pad and stylus. SILK preserves the important properties of pencil and paper: a rough drawing can be produced very quickly and the medium is very flexible. However, unlike a paper sketch, this electronic sketch is interactive and can easily be modified. In addition, our system allows designers to examine, annotate, and edit a complete history of the design. When the designer is satisfied with this early prototype, SILK can transform the sket...

The design of an effective interactive learning environment requires understanding the intricate relationships among people, tools, and problems. Many end-users do not have the necessary skills, nor the time or patience to compose programs from computer science-sanctioned programming primitives. End-users require environments that elevate the task of programming to the manipulation of components that are directly pertinent to the problems to be solved. This paper introduces the Agentsheets programming substrate employed by designers to create interactive learning environments that are geared toward end-users solving specific problems. A number of educational

ing methods; fractals; information visualization; program display; UI theory 1. INTRODUCTION As computer systems evolve, the capability of restoring and managing information increases more and more. At the same time, computer users must view increasing amounts of information through video displays which are physically limited in size. Displaying information 1 effectively is a main concern in many software applications. For example, in visual programming systems[Shu 1988], graphic representations become very complex if the number of visual elements increases. In hypertext 1 The word "information" is used as a structured set of primitive elements which is specific to each application. Author's address: 481 Minor Hall, School of Optometry, University of California, Berkeley, CA 94720-2020. email: koike@milo.berkeley.edu; (permanent address: Graduate School of Information Systems, University of Electro-Communications, 1--5--1, Chofugaoka, Chofu, Tokyo 182, Japan. email: koike@cas.uec.a...

Object-oriented class libraries offer the potential for individual researchers to manage the large bodies of code generated in the experimental development of complex interactive systems. This article analyzes the structure of such a class library that supports the rapid prototyping of a wide range of systems including collaborative networking, shared documents, hypermedia, machine learning, knowledge acquisition and knowledge representation, and various combinations of these technologies. The overall systems architecture is presented in terms of a heterogeneous collection of systems providing a wide range of application functionalities. Examples are given of group writing, multimedia and knowledge-based systems which are based on combining these functionalities. The detailed design issues of the knowledge representation server component of the system are analyzed in terms of requirements, current state-of-the-art, and the underlying theoretical principles that lead to an effective obj...

Document retrieval is a highly interactive process dealing with large amounts of information. Visual representations can provide both a means for managing the complexity of large information structures and an interface style well suited to interactive manipulation. The system we have designed utilizes visually displayed graphic structures and a direct manipulation interface style to supply an integrated environment for retrieval. A common visually displayed network structure is used for query, document content, and term relations. A query can be modified through direct manipulation of its visual form by incorporating terms from any other information structure the system displays. An associative thesaurus of terms and an inter-document network provide information about a document collection that can complement other retrieval aids. Visualization of these large data structures makes use of fisheye views and overview diagrams to help overcome some of the inherent difficulties of orientation and navigation in large information structures.

Modern computer systems routinely present information to the user as a combination of text and diagrammatic images, described as "graphical user interfaces". Practitioners and researchers in Human-Computer Interaction (HCI) generally believe that the value of these diagrammatic representations is derived from metaphorical reasoning; they communicate abstract information by depicting a physical situation from which the abstractions can be inferred. This assumption has been prevalent in HCI research for over 20 years, but has seldom been tested experimentally. This thesis analyses the reasons why diagrams are believed to assist with abstract reasoning. It then presents the results of a series of experiments testing the contribution of metaphor to comprehension, problem solving, explanation and memory tasks carried out using a range of different diagrams. The results indicate that explicit metaphors provide surprisingly little benefit for cognitive tasks using diagrams as an external re...

Designers seeking to improve human-computer interfaces, particularly those concerned with programming environments, often assume that "graphics" will always result in an improvement over "text." Such claims are especially difficult to assess, given that people have used the terms "text" and "graphics" in different and conflicting ways throughout the literature.

By marrying traditional methods for computer programming with an artistic temperament, we give birth to a new phenomenon: the aesthetic program. Our work builds on visual approaches in programming as well as modeling for software, where I envision a gradual evolution from program to model. The need for the aesthetic model is strengthened with the importance of personalized, individually-tailored, models. I, and my students, have formulated the rube Project methodology around the use of 3D web-based virtual world construction of models. Initial results suggest that these models are artistic, while containing sufficient symbolism and concise metaphoric mapping as to be executable on a computer.

A new programming course to prepare novices for the traditional Computer Science 1 course (CS1) is proposed. The course uses 3-D interactive animation in a novice-friendly environment to introduce object-oriented programming concepts and help students develop problem-solving skills. Pedagogical issues are presented that involve the use of visualization and graphics concepts, the notion of state, and programming language concerns. A study of practice and experimentation with this course is underway. Early results are summarized along with observed benefits and concerns. USING ANIMATED 3D GRAPHICS TO PREPARE NOVICES FOR CS1