The concept of a linguistic variable and its application to approximate reasoning—II☆

The concept of an agent has become important in both Artificial Intelligence (AI) and mainstream computer science. Our aim in this paper is to point the reader at what we perceive to be the most important theoretical and practical issues associated with the design and construction of intelligent agents. For convenience, we divide these issues into three areas (though as the reader will see, the divisions are at times somewhat arbitrary). Agent theory is concerned with the question of what an agent is, and the use of mathematical formalisms for representing and reasoning about the properties of agents. Agent architectures can be thought of as software engineering models of agents;researchers in this area are primarily concerned with the problem of designing software or hardware systems that will satisfy the properties specified by agent theorists. Finally, agent languages are software systems for programming and experimenting with agents; these languages may embody principles proposed by theorists. The paper is not intended to serve as a tutorial introduction to all the issues mentioned; we hope instead simply to identify the most important issues, and point to work that elaborates on them. The article includes a short review of current and potential applications of agent technology.

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Intelligent Agents: Theory and Practice

物件導向軟體之架構(Object-Oriented Software Construction)探討

The Globus system is intended to achieve a vertically integrated treatment of application, middleware, and net work. A low-level toolkit provides basic mechanisms such as communication, authentication, network information, and data access. These mechanisms are used to con struct various higher level metacomputing services, such as parallel programming tools and schedulers. The long- term goal is to build an adaptive wide area resource environment AWARE, an integrated set of higher level services that enable applications to adapt to heteroge neous and dynamically changing metacomputing environ ments. Preliminary versions of Globus components were deployed successfully as part of the I-WAY networking experiment.

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Globus: a Metacomputing Infrastructure Toolkit

The Generative Lexicon

According to the interactive view of computation, communication happens during the computation, not before or after it. This approach, distinct from concurrency theory and the theory of computation, represents a paradigm shift that changes our understanding of what is computation and how it is modeled. Interaction machines extend Turing machines with interaction to capture the behavior of concurrent systems, promising to bridge these two fields. This promise is hindered by the widespread belief, incorrectly known as the Church-Turing thesis, that no model of computation more expressive than Turing machines can exist. Yet Turing's original thesis only refers to the computation of functions and explicitly excludes other computational paradigms such as interaction. In this paper, we identify and analyze the historical reasons for this widespread belief. Only by accepting that it is false can we begin to properly investigate formal models of interaction machines. We conclude the paper by presenting one such model, Persistent Turing Machines (PTMs). PTMs capture sequential interaction, which is a limited form of concurrency; they allow us to formulate the Sequential Interaction Thesis, going beyond the expressiveness of Turing machines and of the Church-Turing thesis.

The church-turing thesis: breaking the myth

The classical view of computing positions computation as a closed-box transformation of inputs (rational numbers or finite strings) to outputs. According to the interactive view of computing, computation is an ongoing interactive process rather than a function-based transformation of an input to an output. Specifically, communication with the outside world happens during the computation, not before or after it. This approach radically changes our understanding of what is computation and how it is modeled. The acceptance of interaction as a new paradigm is hindered by the Strong Church---Turing Thesis (SCT), the widespread belief that Turing Machines (TMs) capture all computation, so models of computation more expressive than TMs are impossible. In this paper, we show that SCT reinterprets the original Church---Turing Thesis (CTT) in a way that Turing never intended; its commonly assumed equivalence to the original is a myth. We identify and analyze the historical reasons for the widespread belief in SCT. Only by accepting that it is false can we begin to adopt interaction as an alternative paradigm of computation. We present Persistent Turing Machines (PTMs), that extend TMs to capture sequential interaction. PTMs allow us to formulate the Sequential Interaction Thesis, going beyond the expressiveness of TMs and of the CTT. The paradigm shift to interaction provides an alternative understanding of the nature of computing that better reflects the services provided by today's computing technology.

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The Interactive Nature of Computing: Refuting the Strong Church---Turing Thesis

An algebraic model of subtype and inheritance

T HE WORLD BECAME A SMALLER PLACE IN THE 20TH CENTURY. TRANSportation technology caused physical distances to shrink by several orders of magnitude, and telecommunications technology made terrestrial distances insignificant. The transformation of the world into a global village caused revolutionary changes in the physical and social infrastructure, rivaling those of the industrial revolution. Even the types of jobs people did changed or disappeared, replaced by new jobs that had never existed before. Other results included great changes in society's economic infrastructure. Computer technology further supports globalization by radically changing the economics of communication , so geographic proximity is even less a requirement for effective collaboration and business interaction. Moreover, globalization of computer technology makes possible new forms of technical and social organization that influence the efficiency of business enterprises as well as the quality of life of ordinary citizens. However, our ability to influence the evolution of globalization depends on our understanding of the technology of globalization and its social implications. Globalization occurs at both the national and international levels. Infrastructure is initially developed

Globalizing business, education, culture through the Internet

This paper examines the limitations of Turing Machines as a complete model of computation, and presents several models that extend Turing Machines. Dynamic interaction of clients and servers on the Internet, an infinite adaptation from evolutionary computation, and robots sensing and acting are some examples of areas that cannot be properly described using Turing Machines and algorithms. They require new models of computation going beyond Turing Machines. We refer to such new models as superTuring models of computation. Three superTuring models of computation, namely Interaction Machines, the π calculus and the $-calculus are presented and explained, focussing on why they are better for the solution of computational problems. We expect that superTuring computation will become the central programming paradigm in the future.

Peter Wegner

Papers

The church-turing thesis: breaking the myth

The Interactive Nature of Computing: Refuting the Strong Church---Turing Thesis

An algebraic model of subtype and inheritance

Globalizing business, education, culture through the Internet

New Models of Computation