This paper considers a range of theoretical approaches to the understanding of organisations and the implications these views have for the design of computer supported cooperative work systems. Organisations have ofte...
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The mathematical treatment of the concepts of vagueness and approximation is of increasing importance in artificial intelligence and related research. The theory of fuzzy sets was created by Zadeh [Z] to allow represe...
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The mathematical treatment of the concepts of vagueness and approximation is of increasing importance in artificial intelligence and related research. The theory of fuzzy sets was created by Zadeh [Z] to allow representation and mathematical manipulation of situations of partial truth, and proceeding from this a large amount of theoretical and applied development of this concept has occurred. The aim of this paper is to develop a natural logic and set theory that is a candidate for the formalisation of the theory of fuzzy sets. In these theories the underlying logic of properties and sets is intuitionistic, but there is a subset of formulae that are ‘crisp’, classical and two-valued, which represent the certain information. Quantum logic or logics weaker than intuitionistic can also be adopted as the basis, as described in [L]. The relationship of this theory to the intensional set theory MZF of [Gd] and the global intuitionistic set theory GIZF of Takeuti and Titani [TT] is also treated.
作者：
HOARE, CAROxford University
Computing Laboratory Programming Research Group 8-11 Keble Road Oxford OX1 3QD UK
This paper shows how propositional logic may be used to reason about synchronous combinational switching circuits implemented in C-mos. It develops a simple formalism and theory for describing and predicting their beh...
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This paper shows how propositional logic may be used to reason about synchronous combinational switching circuits implemented in C-mos. It develops a simple formalism and theory for describing and predicting their behaviour. On this it builds a calculus of design which is driven by proof obligations. The design philosophy for software introduced in [1] is thereby extended to a certain kind of hardware design. No prior knowledge of hardware is assumed of the reader;but useful background, motivation, examples and pictures may be found in [2]. Many of the problems described in that paper have been solved in this one.
The sliding-window protocol is specified using the notation of Communicating Sequential Processes and its partial correctness is proved using the trace semantics. First the stop-and-wait protocol is defined;its correc...
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The sliding-window protocol is specified using the notation of Communicating Sequential Processes and its partial correctness is proved using the trace semantics. First the stop-and-wait protocol is defined;its correctness, that it forms a 1-place buffer, is almost evident. Next the alternating-bit protocol is defined and described in terms of the stop-and-wait protocol, and its correctness deduced from that of the stop-and-wait protocol. Finally the sliding-window protocol is described in terms of the alternating-bit protocol and its correctness deduced accordingly. The paper has two thrusts: that modularity of a specification helps to structure proofs about it (in this case, proofs that the protocols implement buffers);and that refinement in CSP leads to structured, correct implementation in occam. In support of the latter point the appendix contains a refinement and implementation of the protocols in occam 2.
It is known that functional refinement does not preserve the security properties of a system. The authors propose a trace-based method for specifying the security properties of a system and a method which ensures that...
We give here a general definition of term rewriting in the simply typed λ-calculus, and use it to define higher-order forms of term rewriting systems, and equational unification and their properties. This provides a ...
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This paper describes a scheme for representing heterogeneous array circuits, in particular those which have been optimised by pipelining or by transposition. Equations for correctness-preserving transformations of the...
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It is known that functional refinement does not preserve the security properties of a system. The authors propose a trace-based method for specifying the security properties of a system and a method which ensures that...
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It is known that functional refinement does not preserve the security properties of a system. The authors propose a trace-based method for specifying the security properties of a system and a method which ensures that this security is preserved under refinement. They include an example to illustrate the use of the definitions and make use of non-interference (as defined in their notation).< >
A hybrid architecture for machine vision is described. The primary components of the architecture are a Datacube pipelined image processor, a configurable network of 32 T800 transputers, a Sun-4 workstation and a spec...
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A hybrid architecture for machine vision is described. The primary components of the architecture are a Datacube pipelined image processor, a configurable network of 32 T800 transputers, a Sun-4 workstation and a special-purpose interface connecting the Datacube to the transputer network. The implementation of a 3D structure-from-motion vision algorithm (Droid) on this architecture is described. This algorithm reconstructs 3D structure by analysing image sequences obtained from a moving camera. The Datacube handles the image digitisation, storage and display; the transputer network performs the feature extraction (corner points) in parallel and the Sun-4 computes the 3D-isation. In this application, which was demonstrated live during a recent ESPRIT conference in Brussels, the architecture delivers a performance of greater than 1 frame per second-17 times the performance of a Sun-4 alone.< >
A novel process algebra is presented;algebraic expressions specify delay-insensitive circuits in terms of voltage-level transitions on wires. The approach appears to have several advantages over traditional state-grap...
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