Visual query systems (VQSs) are query systems for databases that use visual representations to depict the domain of interest and express related requests. VQSs can be seen as an evolution of query languages adopted into database management systems; they are designed to improve the effectiveness of the human-computer communication. Thus, their most important features are those that determine the nature of the human-computer dialogue. In order to survey and compare existing VQSs used for querying traditional databases, we first introduce a classification based on such features, namely the adopted visual representations and the interaction strategies. We then identify several user types and match the VQS classes against them, in order to understand which kind of system may be suitable for each kind of user. We also report usability experiments which support our claims. Finally, some of the most important open problems in the VQS area are described. 1.

This article describes learning with media as a complementary process within which representations are constructed and procedures performed, sometimes by the learner and sometimes by the medium. It reviews research on learning with books, television, computers, and multimedia environments. These media are distinguished by cognitively relevant characteristics of their technologies, symbol systems, and processing capabilities. Studies are examined that illustrate how these characteristics, and instructional designs that employ them, interact with learner and task characteristics to influence the structure of mental representations and cognitive processes. Of specific interest is the effect of media characteristics on the structure, formation, and modification of mental models. Implications for research and practice are discussed Do media influence learning? The research reviewed in this article suggests that capabilities of a particular medium, in conjunction with methods that take advantage of

This article addresses the position taken by Clark (1983) that media do not influence learning under any conditions. The article reframes the questions raised by Clark to explore the conditions under which media will influence learning. Specifically, it posits the need to consider the capabilities of media, and the methods that employ them, as they interact with the cognitive and social processes by which knowledge is constructed. This approach is examined within the context of two major media-based projects, one which uses computers and the other video. The article discusses the implications of this approach for media theory, research, and practice. Do media influence learning? Ten years ago, Richard Clark (1983) reviewed the results of comparative research on educational media and claimed that they provide consistent evidence "... for the generalization that there are no learning benefits to be gained from employing any specific medium to deliver instruction " (p. 445). According to Clark, the results of those studies that appear to favor one medium over another are due not to the medium but to the method or content that are introduced along with the

It often makes sense to employ both text and pictures when referring to world objects. In this paper 1 , we present a model for referring which is based on the assumption that concepts may be activated not only by text, but also by pictures and text-picture combinations. By means of a case study, we demonstrate that failure and success of referring acts can be explained by the user's ability to infer certain links between mental representations and object descriptions. Finally, we show how the model has been incorporated into a plan-based multimedia presentation system by defining operators for concept activation. 1 Introduction From a speech act theoretical point of view, referring is a planned action to achieve certain goals (cf. [Appelt & Kronfeld 87]). Although natural language may be the most conventional vehicle for referring, it has been widely accepted that pictures can be used as well. For example, Goodman[Goodman 69] points out that pictures can be employed to refer to bot...

The argument presented in this article is that the premises governing human-technology interaction partly derive from the distinctive ways by which each technology defines a domain of reference, and organizes and codifies knowledge and experience within it. While social in its origins and its implications, technology constitutes a distinct realm of human experience that is not reducible to social or institutional relations. Drawing on Goodman’s (1976, 1978) cognitive philosophy the article proposes a scheme for analyzing the very architecture of items and relations underlying the constitution of cognition-based artifacts. Such an analysis is used as a basis for inferring the malleability and negotiability of technologies and the forms by which they admit human involvement and participation. 1

We live in an era when everyday activities are shaped by environments that are not only artificial—almost half of humanity lives in cities—but also mediated. Emotional and cognitive activities in all levels and segments of society are increasingly vested in information-rich venues supported by television, radio, telephone, and computer networks. Even in very remote areas, hunters and farmers watch satellite broadcasts and play battery-operated video games. And in the depths of the Amazon River basin, tribes use tiny video cameras to document territorial encroachments and destruction of rain forest habitat. 10.1 OVERVIEW This chapter explores the metaphor of media as lived environments. A medium can be considered an environment to the extent that it supports both the perception of opportunities for acting and some means for acting. This environmental metaphor can help us understand how media users exercise their powers of perception, mobility, and agency within the constraints

Classifications of visualization are often based on technical criteria, and leave out artistic ways of visualizing information. Understanding the differences between information visualization and other forms of visual communication provides important insights into the way the field works, though, and also shows the path to new approaches. We propose a classification of several types of information visualization based on aesthetic criteria. The notions of artistic and pragmatic visualization are introduced, and their properties discussed. Finally, the idea of visualization criticism is proposed, and its rules are laid out. Visualization criticism bridges the gap between design, art, and technical/pragmatic information visualization. It guides the view away from implementation details and single mouse clicks to the meaning of a visualization. 1

My task is to reflect on the papers in the two Special Issues on "Representations and the

Computer-based visual languages have been developed primarily in order to help people program and operate computers. Now that many people in the world have personal computers with good graphics and Internet connections, we are seeing a great deal of informal electronic visual communication via web pages. More formal visual languages can be expected to appear on the Internet in the near future. Visual languages offer various possible advantages to textual email, such as permitting communication between people who don't speak or read the same textual language and such as permitting the incorporation of rich graphical material. Designing these languages requires making some important decisions about ontology, visual representation, interactivity, and how users learn the language, as well as about the more traditional issues of language design such as syntax. The power of the computer to generate alternative views of a language object can be harnessed by incorporating an iconic-symbolic co...

This dissertation is the product of a series of significant evolutions of my initial ideas. There are many people who deserve credit for ensuring that these changes were in the right direction. They include Charles H. Anderson,