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Interaction Categories and the Foundations of Typed Concurrent Programming
 In Deductive Program Design: Proceedings of the 1994 Marktoberdorf Summer School, NATO ASI Series F
, 1995
"... We propose Interaction Categories as a new paradigm for the semantics of functional and concurrent computation. Interaction categories have specifications as objects, processes as morphisms, and interaction as composition. We introduce two key examples of interaction categories for concurrent compu ..."
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Cited by 123 (19 self)
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We propose Interaction Categories as a new paradigm for the semantics of functional and concurrent computation. Interaction categories have specifications as objects, processes as morphisms, and interaction as composition. We introduce two key examples of interaction categories for concurrent computation and indicate how a general axiomatisation can be developed. The upshot of our approach is that traditional process calculus is reconstituted in functorial form, and integrated with type theory and functional programming.
Graph Types For Monadic Mobile Processes
 University of Edinburgh
, 1996
"... . While types for name passing calculi have been studied extensively in the context of sorting of polyadic ßcalculus [5, 34, 9, 28, 32, 19, 33, 10, 17], the same type abstraction is not possible in the monadic setting, which was left as an open issue by Milner [21]. We solve this problem with an ex ..."
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Cited by 60 (7 self)
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. While types for name passing calculi have been studied extensively in the context of sorting of polyadic ßcalculus [5, 34, 9, 28, 32, 19, 33, 10, 17], the same type abstraction is not possible in the monadic setting, which was left as an open issue by Milner [21]. We solve this problem with an extension of sorting which captures dynamic aspects of process behaviour in a simple way. Equationally this results in the full abstraction of the standard encoding of polyadic ßcalculus into the monadic one: the sorted polyadic ßterms are equated by a basic behavioural equality in the polyadic calculus if and only if their encodings are equated in a basic behavioural equality in the typed monadic calculus. This is the first result of this kind we know of in the context of the encoding of polyadic name passing, which is a typical example of translation of highlevel communication structures into ß calculus. The construction is general enough to be extendable to encodings of calculi with mo...
The Role of Dialectics in Defeasible Argumentation
, 1994
"... In A Mathematical Treatment of Defeasible Reasoning [8], or MTDR, a clear and theoretically sound structure for a reasoning system was introduced. Since its publication other proposals have been advanced [2, 9, 6, 1], some of them containing valuable observations on this foundation. This paper prese ..."
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Cited by 27 (18 self)
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In A Mathematical Treatment of Defeasible Reasoning [8], or MTDR, a clear and theoretically sound structure for a reasoning system was introduced. Since its publication other proposals have been advanced [2, 9, 6, 1], some of them containing valuable observations on this foundation. This paper presents further developments based on the MTDR framework. Two main results are shown. Firstly, several alternative implementations of MTDR were based on dialectical concepts, which needed proper formalization. Secondly, the confrontation of the resulting formalism with the abovementioned work of other researchers has shown that some of the original definitions needed to be honed to avoid fallacious reasoning. The resulting, evolved,...
Naming proofs in classical propositional logic
 IN PAWE̷L URZYCZYN, EDITOR, TYPED LAMBDA CALCULI AND APPLICATIONS, TLCA 2005, VOLUME 3461 OF LECTURE
"... We present a theory of proof denotations in classical propositional logic. The abstract definition is in terms of a semiring of weights, and two concrete instances are explored. With the Boolean semiring we get a theory of classical proof nets, with a geometric correctness criterion, a sequentiali ..."
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Cited by 24 (8 self)
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We present a theory of proof denotations in classical propositional logic. The abstract definition is in terms of a semiring of weights, and two concrete instances are explored. With the Boolean semiring we get a theory of classical proof nets, with a geometric correctness criterion, a sequentialization theorem, and a strongly normalizing cutelimination procedure. This gives us a “Boolean ” category, which is not a poset. With the semiring of natural numbers, we obtain a sound semantics for classical logic, in which fewer proofs are identified. Though a “real” sequentialization theorem is missing, these proof nets have a grip on complexity issues. In both cases the cut elimination procedure is closely related to its equivalent in the calculus of structures.
Chu spaces and their interpretation as concurrent objects
, 2005
"... A Chu space is a binary relation =  from a set A to an antiset X defined as a set which transforms via converse functions. Chu spaces admit a great many interpretations by virtue of realizing all small concrete categories and most large ones arising in mathematical and computational practice. Of pa ..."
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Cited by 21 (0 self)
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A Chu space is a binary relation =  from a set A to an antiset X defined as a set which transforms via converse functions. Chu spaces admit a great many interpretations by virtue of realizing all small concrete categories and most large ones arising in mathematical and computational practice. Of particular interest for computer science is their interpretation as computational processes, which takes A to be a schedule of events distributed in time, X to be an automaton of states forming an information system in the sense of Scott, and the pairs (a, x) in the =  relation to be the individual transcriptions of the making of history. The traditional homogeneous binary relations of transition on X and precedence on A are recovered as respectively the right and left residuals of the heterogeneous binary relation =  with itself. The natural algebra of Chu spaces is that of linear logic, made a process algebra by the process interpretation.
L.: Constructing free Boolean categories
, 2005
"... By Boolean category we mean something which is to a Boolean algebra what a category is to a poset. We propose an axiomatic system for Boolean categories, which is different in several respects from the ones proposed recently. In particular everything is done from the start in a *autonomous category ..."
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Cited by 21 (6 self)
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By Boolean category we mean something which is to a Boolean algebra what a category is to a poset. We propose an axiomatic system for Boolean categories, which is different in several respects from the ones proposed recently. In particular everything is done from the start in a *autonomous category and not in a weakly distributive one, which simplifies issues like the Mix rule. An important axiom, which is introduced later, is a “graphical ” condition, which is closely related to denotational semantics and the Geometry of Interaction. Then we show that a previously
ThresholdBased Dynamic Replication in LargeScale VideoonDemand Systems
, 1998
"... Recent advances in high speed networking technologies and video compression techniques have made VideoonDemand (VOD) services feasible. A largescale VOD system imposes a large demand on I/O bandwidth and storage resources, and therefore, parallel disks are typically used for providing VOD service ..."
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Cited by 18 (8 self)
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Recent advances in high speed networking technologies and video compression techniques have made VideoonDemand (VOD) services feasible. A largescale VOD system imposes a large demand on I/O bandwidth and storage resources, and therefore, parallel disks are typically used for providing VOD service. Although striping of movie data across a large number of disks can balance the utilization among these disks, such a striping technique can exhibit additional complexity, for instance, in data management, such as synchronization among disks during data delivery, as well as in supporting fault tolerant behavior. Therefore, it is more practical to limit the extent of data striping, for example, by arranging the disks in groups (or nodes) and then allowing intragroup (or intranode) data striping only. With multiple striping groups, however, we may need to assign a movie to multiple nodes so as to satisfy the total demand of requests for that movie. Such an approach gives rise to several design issues, including: (1) what is the right number of copies of each movie we need so as to satisfy the demand and at the same time not waste storage capacity, (2) how to assign these movies to dierent nodes in the system, and (3) what are ecient approaches to altering the number of copies of each movie (and their placement) when the need for that arises. In this paper, we study an approach to dynamically recon guring the VOD system so as to alter the number of copies of each movie maintained on the server as the access demand for these movies uctuates. We propose various approaches to addressing the above stated issues, which result in a VOD design that is adaptive to the changes in data access patterns. Performance evaluation is carried out to quantify the costs and the performance g...
Microarray Optimizations: Increasing Spot Accuracy and Automated Identification of True Microarray Signals
, 2002
"... In this paper, fluorescent microarray images and various analysis techniques are described to improve the microarray data acquisition processes. Signal intensities produced by rarely expressed genes are initially correctly detected, but they are often lost in corrections for background, log or ratio ..."
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Cited by 17 (1 self)
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In this paper, fluorescent microarray images and various analysis techniques are described to improve the microarray data acquisition processes. Signal intensities produced by rarely expressed genes are initially correctly detected, but they are often lost in corrections for background, log or ratio. Our analyses indicate that a simple correlation between the mean and median signal intensities may be the best way to eliminate inaccurate microarray signals. Unlike traditional quality control methods, the low intensity signals are retained and inaccurate signals are eliminated in this mean and median correlation. With larger amounts of microarray data being generated, it becomes increasingly more difficult to analyze data on a visual basis. Our method allows for the automatic quantitative determination of accurate and reliable signals, which can then be used for normalization. We found that a mean to median correlation of 85% or higher not only retains more data than current methods, but the retained data is more accurate than traditional thresholds or common spot flagging algorithms. We have also found that by using pin microtapping and microvibrations, we can control spot quality independent from initial PCR volume.
Efficiency of JADE agent platform
, 2005
"... Agent oriented programming is often claimed to become the next breakthrough in development and implementation of largescale complex software systems. At the same time it is rather difficult to find successful applications of agent technology, in particular when largescale systems are considered. ..."
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Cited by 15 (7 self)
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Agent oriented programming is often claimed to become the next breakthrough in development and implementation of largescale complex software systems. At the same time it is rather difficult to find successful applications of agent technology, in particular when largescale systems are considered. The aim of this paper is to investigate if one of the possible limits could be the scalability of existing agent environments. For this purpose we have selected JADE agent platform and investigated its performance in a number of testscenarios. Results of our experiments are presented and discussed.