Ronald M. Baecker

A Principled Taxonomy of Software Visualization

Abstract In the early 1980s researchers began building systems to visualize computer programs and algorithms using newly emerging graphical workstation technology. After more than a decade of advances in interface technology, a large variety of systems has been built and many different aspects of the visualization process have been investigated. As in any new branch of a science, a taxonomy is required so that researchers can use a common language to discuss the merits of existing systems, classify new ones (to see if they really are new) and identify gaps which suggest promising areas for further development. Several authors have suggested taxonomies for these visualization systems, but they have been ad hoc and have relied on only a handful of characteristics to describe a large and diverse area of work. Another major drawback of these taxonomies is their inability to accommodate expansion: there is no clear way to add new categories when the need arises. In this paper we present a detailed taxonomy of systems for the visualization of computer software. This taxonomy was derived from an established black-box model of software and is composed of a hierarchy with six broad categories at the top and over 30 leaf-level nodes at four hierarchical levels. We describe 12 important systems in detail and apply the taxonomy to them in order to illustrate its features. After discussing each system in this context, we analyse its coverage of the categories and present a research agenda for future work in the area.

The user-centered iterative design of collaborative writing software

This paper presents the user-centred iterative design of software that supports collaborative writing. The design grew out of a study of how people write together that included a survey of writers and a laboratory study of writing teams linked by a variety of communications media. The resulting taxonomy of collaborative writing is summarized in the paper, followed by a list of design requirements for collaborative writing software suggested by the work. The paper describes two designs of the software. The first prototype supports synchronous writing and editing from workstations linked over local area and wide area networks. The second prototype also supports brainstorming, outlining, and document review, as well as asynchronous work. Lessons learned from the user testing and actual usage of the two systems are also presented.This paper presents the user-centred iterative design of software that supports collaborative writing. The design grew out of a study of how people write together that included a survey of writers and a laboratory study of writing teams linked by a variety of communications media. The resulting taxonomy of collaborative writing is summarized in the paper, followed by a list of design requirements for collaborative writing software suggested by the work. The paper describes two designs of the software. The first prototype supports synchronous writing and editing from workstations linked over local area and wide area networks. The second prototype also supports brainstorming, outlining, and document review, as well as asynchronous work. Lessons learned from the user testing and actual usage of the two systems are also presented.

Getting the right design and the design right

We present a study comparing usability testing of a single interface versus three functionally equivalent but stylistically distinct designs. We found that when presented with a single design, users give significantly higher ratings and were more reluctant to criticize than when presented with the same design in a group of three. Our results imply that by presenting users with alternative design solutions, subjective ratings are less prone to inflation and give rise to more and stronger criticisms when appropriate. Contrary to our expectations, our results also suggest that usability testing by itself, even when multiple designs are presented, is not an effective vehicle for soliciting constructive suggestions about how to improve the design from end users. It is a means to identify problems, not provide solutions.

Software visualization for debugging

To illustrate these ideas, we present three visualization approaches we have explored—algorithm animation, typographic source code presentation, and interactive auralization for debugging—demonstrating the richness of software visualization media and portraying design trade-offs inherent in their use. We use a 30-minute film (designed to teach nine sorting algorithms) to demonstrate the power of algorithm animation. We show how the design and typesetting of computer program source text can enhance the program’s readability. And we show how a programming environment we created—LogoMedia—is useful for the interactive construction of visualizations during program creation and debugging. Software Vi for Debugging

A death in the family: opportunities for designing technologies for the bereaved

Following the death of a loved one, bereaved family members use technology in several ways to respond to their loss. However, very little is known about how technology intersects with the lives of the bereaved. We present a survey and interview study which examines how the bereaved inherit personal digital devices, use technology to remember the deceased, and reflect on their own digital estates. The study provides one of the first characterizations of technology use by the bereaved, and presents a set of empirically-grounded design opportunities and challenges.

The effect of speech recognition accuracy rates on the usefulness and usability of webcast archives

The widespread availability of broadband connections has led to an increase in the use of Internet broadcasting (webcasting). Most webcasts are archived and accessed numerous times retrospectively. In the absence of transcripts of what was said, users have difficulty searching and scanning for specific topics. This research investigates user needs for transcription accuracy in webcast archives, and measures how the quality of transcripts affects user performance in a question-answering task, and how quality affects overall user experience. We tested 48 subjects in a within-subjects design under 4 conditions: perfect transcripts, transcripts with 25% Word Error Rate (WER), transcripts with 45% WER, and no transcript. Our data reveals that speech recognition accuracy linearly influences both user performance and experience, shows that transcripts with 45% WER are unsatisfactory, and suggests that transcripts having a WER of 25% or less would be useful and usable in webcast archives.

Participatory design of an orientation aid for amnesics

We present the participatory design and evaluation of an orientation aid for individuals who have anterograde amnesia. Our design team included six amnesics who have extreme difficulty storing new memories. We describe the methods we used to enable the participation of individuals with such severe cognitive impairments. Through this process, we have conceived, designed, and developed the OrientingTool, a software application for Personal Digital Assistants that can be used by amnesics to orient themselves when feeling lost or disoriented. Two complementary studies were conducted to evaluate the effectiveness of this tool in ecologically valid contexts. Our findings suggest that the OrientingTool can improve an amnesics independence and confidence in managing situations when disoriented, and that participatory design may be productively used with participants who have significant cognitive disabilities.

A taxonomy of software visualization

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. The authors propose 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.<<ETX>>

Two systems which produce animated representations of the execution of computer programs

This paper describes two prototype systems which facilitate the production of teaching films containing animated representations of the execution of computer programs. With such systems, it is possible for an instructor to produce short quick-and-dirty single-concept film clips with only hours of effort, and more polished material with only slightly more effort. Demonstration clips produced in this way will be shown at the Symposium.

Dealing with death in design: developing systems for the bereaved

Increasingly, systems are being developed and used in ways that involve end of life issues such as death, dying, and bereavement. Yet design considerations and guidelines for technologists working in this sensitive area are not well-established. We therefore report on exploratory fieldwork consisting of focus groups, observations, and consultation with bereavement experts aimed at understanding how technology might be designed to support bereaved parents. From this fieldwork, we derive a set of considerations useful for researchers and designers developing systems that deal specifically with bereavement, and with the end of life more broadly. These considerations focus on interpersonal communication, new ways of being in the world, and materiality. We conclude with a distillation of these considerations into practical design guidelines for working in this area.