The purpose of this paper is to study the fundamental mechanism humans use in argumentation and its role in different major approaches to commonsense reasoning in AI and logic programming. We present three novel results: We develop a theory for argumentation in which the acceptability of arguments is precisely defined. We show that logic programming and nonmonotonic reasoning in AI are different forms of argumentation. We show that argumentation can be viewed as a special form of logic programming with negation as failure. This result introduces a general method for generating metainterpreters for argumentation systems. 1.

This survey characterizes an emerging research area, sometimes called coordination theory, that focuses on the interdisciplinary study of coordination. Research in this area uses and extends ideas about coordination from disciplines such as computer science, organization theory, operations research, economics, linguistics, and psychology. A key insight of the framework presented here is that coordination can be seen as the process of managing dependencies among activities. Further progress, therefore, should be possible by characterizing different kinds of dependencies and identifying the coordination processes that can be used to manage them. A variety of processes are analyzed from this perspective, and commonalities across disciplines are identified. Processes analyzed include those for managing shared resources, producer/consumer relationships, simultaneity constraints, and tank/subtask dependencies. Section 3 summarizes ways of applying a coordination perspective in three different domains: (1) understanding the effects of information technology on human organizations and markets, (2) designing cooperative work tools, and (3) designing distributed and parallel computer systems. In the final section, elements of a research

This paper describes a language that is intended to support software engineers in the development of information systems throughout the software lifecycle. This language is not a programming language. Following the example of a number of other software engineering projects, our work is based on the premise that information system development is knowledge-intensive and that the primary responsibility of any language intended to support this task is to be able to formally represent the relevant knowledge.

We present an abstract framework for default reasoning, which includes Theorist, default logic, logic programming, autoepistemic logic, non-monotonic modal logics, and certain instances of circumscription as special cases. The framework can be understood as a generalisation of Theorist. The generalisation allows any theory formulated in a monotonic logic to be extended by a defeasible set of assumptions. An assumption can be defeated (or "attacked") if its "contrary" can be proved, possibly with the aid of other conflicting assumptions. We show that, given such a framework, the standard semantics of most logics for default reasoning can be understood as sanctioning a set of assumptions, as an extension of a given theory, if and only if the set of assumptions is conflict-free (in the sense that it does not attack itself) and it attacks every assumption not in the set. We propose a more liberal, argumentation-theoretic semantics, based upon the notion of admissible extension in logic pro...

Identifying sentiments (the affective parts of opinions) is a challenging problem. We present a system that, given a topic, automatically finds the people who hold opinions about that topic and the sentiment of each opinion. The system contains a module for determining word sentiment and another for combining sentiments within a sentence. We experiment with various models of classifying and combining sentiment at word and sentence levels, with promising results. 1

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Logical models of argument formalize commonsense reasoning while taking process and computation seriously. This survey discusses the main ideas which characterize different logical models of argument. It presents the formal features of a few main approaches to the modeling of argumentation. We trace the

In this paper, we report about the design, development, and implementation of the SEPIA cooperative hypermedia authoring environment. It provides results on the following aspects of SEPIA: persistent and shared data storage, hypermedia data model with composites, sophisticated and comprehensive authoring functionality, support for a new rhetoric and for cooperative work. We start by identifying the challenge of hypermedia authoring and production which serves as the driving force for our development. Using interacting problem spaces as the vehicle for modelling the dynamic aspects of authoring, we arrive at a set of requirements answered by the concept of "activity spaces". The design of coherent hyperdocuments is facilitated by our "construction kit". Furthermore, we describe the extensions and modifications necessary to support multiple authors with the cooperative version of SEPIA. The central issue of the paper is the system architecture and its implementation. We describe the basi...

A design rationale (DR) is a representation of the reasoning behind the design of an artifact. In recent years, the use of semiformal notations for structuring arguments about design decisions has attracted much interest within the human-computer interaction and software engineering communities, leading to a number of DR notations and support environments. This paper examines two foundational claims made by argumentation-based DR approaches: that expressing DR as argumentation is useful, and that designers can use such notations. The conceptual and empirical basis for these claims is examined, firstly by surveying relevant literature on the use of argumentation in non-design contexts (from which current DR efforts draw much inspiration), and secondly, by surveying DR work. Evidence is classified according to the research contribution it makes, the kind of data on which claims are based (anecdotal or experimental), the extent to which the claims made are substantiated, and whether or not the users of the approach were also the researchers. In the survey, a trend towards tightly integrating DR with other design representations is noted, but it is argued that taken too far, this may result in the loss of the original vision of argumentative

Hypertext systems have traditionally focused on information management and presentation. In contrast, the Aquanet hypertext system described in this paper is designed to support knowledge structuring tasks. Aquanet is a browser-based tool that allows users to graphically represent information in order to explore its structure. In this paper, we discuss our motivations for developing Aquanet. We then describe the basic concepts underlying the tool and give an overview of the user interface. We close with some brief comments about our initial experiences with the tool in use and some of the directions we see the Aquanet research moving in the near future. from Hypertext `91 Proceedings, San Antonio, Texas, December 15-18, 1991 Draft of: August 28, 1991 10:21 am 1 Aquanet: a hypertext tool to hold your knowledge in place 1 1.