B.S., Engineering College, Brugg-Windisch, 1985
M.S., University of Colorado, 1990
A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement for the degree of Doctor of Philosophy
Department of Computer Science


Cultures deal with their environments by adapting to them and simultaneously changing them. This is particularly true for technological cultures, such as the dynamic culture of computer users. To date, the ability to change computing environments in non-trivial ways has been dependent upon the skill of programming. Because this skill has been hard to acquire, most computer users must adapt to computing environments created by a small number of programmers. In response to the scarcity of programming ability, the computer science community has concentrated on producing general-purpose tools that cover wide spectrums of applications. As a result, contemporary programming languages largely ignore the intricacies arising from complex interactions between different people solving concrete problems in specific domains.

This dissertation describes Agentsheets, a substrate for building domain-oriented, visual, dynamic programming environments that do not require traditional programming skills. It discusses how Agentsheets supports the relationship among people, tools, and problems in the context of four central themes:

(1) Agentsheets features a versatile construction paradigm to build dynamic, visual environments for a wide range of problem domains such as art, artificial life, distributed artificial intelligence, education, environmental design, and computer science theory. The construction paradigm consists of a large number of autonomous, communicating agents organized in a grid, called the agentsheet. Agents utilize different communication modalities such as animation, sound, and speech.

(2) The construction paradigm supports the perception of programming as problem solving by incorporating mechanisms to incrementally create and modify spatial and temporal representations.

(3) To interact with a large number of autonomous entities Agentsheets postulates participatory theater, a human-computer interaction scheme combining the advantages of direct manipulation and delegation into a continuous spectrum of control and effort.

(4) Metaphors serve as mediators between problem solving-oriented construction paradigms and domain-oriented applications. Metaphors are used to represent application semantics by helping people to conceptualize problems in terms of concrete notions. Furthermore, metaphors can simplify the implementation of applications. Application designers can explore and reuse existing applications that include similar metaphors.