Entry consistency is a weak memory consistency model that makes possible the efficient implementation of distributed shared memory (DSM) languages and systems. In this paper we study a way an entry consistency based m...
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ISBN:
(纸本)9783540634409
Entry consistency is a weak memory consistency model that makes possible the efficient implementation of distributed shared memory (DSM) languages and systems. In this paper we study a way an entry consistency based memory model can be integrated into concurrent object-oriented languages. One problem to be solved is how to satisfy the entry consistency requirements when objects include synchronization constraints. We propose a solution based on the definition of a programming model with the following characteristics: (1) the establishment of ownership relations among objects, (2) a distinction between command and query operations, and (3) a lazy wait synchronization mechanism. Preliminary results show that significant speed-ups can be obtained.
Agent-orientedprogramming has been presented as a specialization of object-orientedprogramming (Shoham 1993). This point of view is based on the facts that an agent is basically an entity that has behavioural capabi...
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Agent-orientedprogramming has been presented as a specialization of object-orientedprogramming (Shoham 1993). This point of view is based on the facts that an agent is basically an entity that has behavioural capabilities, its own internal state (the mental state), and that a multi-agent system is defined in terms of a set of those entities and the collaborations established among them. But the mental state of an agent has to represent beliefs, desires and intentions, which are used to deduce the agent's next steps. Logic programming appears to be one of the more appropriate alternatives for expressing that knowledge. Taking into account that the object-oriented and logic paradigms have advantageous characteristics for building agents, we have defined a context in which these paradigms can work together: the Brainstorm Meta-Architecture that permits objects to become agents by associating a meta-level with agent capabilities to them. We have considered in the meta-architecture, internal knowledge being represented by logic formulae. Thus, an object that becomes an agent can express its knowledge through objects and logic clauses. For this goal, we have defined an extension of Prolog to manage operators for beliefs, goals and intentions.
Teaching object-orientedprogramming skills in six hours to school students who have either never programmed, or who have never encountered object-orientedprogramming before, is an ambitious task. Within these time a...
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The denotational semantics of object-orientedprogramming languages (OOPL’s) are used to derive the control and data dependencies that exist within programs and this information is then used to produce parallel objec...
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A software application has been developed for analysis of the International Space Station Thermal Control System for mission operations. This software serves needs unique to spacecraft mission control. Characteristics...
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The proceedings contains 18 papers from the 1997 Conference on object oriented programming, Systems, Languages, and Applications. Topics discussed include: project management and methodology;language and infrastructur...
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The proceedings contains 18 papers from the 1997 Conference on object oriented programming, Systems, Languages, and Applications. Topics discussed include: project management and methodology;language and infrastructure;reuse and testing;architecture and implementation;analysis and design;education;frameworks and patterns;networked computing;languages and implementations;databases;and process metrics.
The proceedings contains 29 papers from the 1997 Annual Conference on object-orientedprogramming, Systems, Languages, and Applications. Topics discussed include: class library evolution;reusability;Java programming l...
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The proceedings contains 29 papers from the 1997 Annual Conference on object-orientedprogramming, Systems, Languages, and Applications. Topics discussed include: class library evolution;reusability;Java programming language;type parameterization;parasitic methods for multi-methods implementation for Java;dynamic interdependent objects collections;object-relational database systems;World Wide Web;call graph construction;dynamic dispatch without virtual functions;efficient type inclusion tests;aspect-orientedprogramming;software agents and network-based software;distributed systems tools;ephemerons;common-object request broker architecture (CORBA);and software blueprints.
We start with a general approach to introducing software fault tolerance (SFT) into object-oriented (OO) systems [Xu, J., Randell, B., Rubira, C.M.F., Stroud, R.J., 1995. Toward an object-oriented approach to software...
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We start with a general approach to introducing software fault tolerance (SFT) into object-oriented (OO) systems [Xu, J., Randell, B., Rubira, C.M.F., Stroud, R.J., 1995. Toward an object-oriented approach to software fault-tolerance. In: Avreski, D. (Ed.) Fault-Tolerant Parallel and Distributed Systems. DEEE CS Press, Silver Spring, MD.] and proceed in two directions. The first one is the use of SFT schemes within standard OO languages. New questions which arise when we are dealing with these languages are addressed. Our intention is to thoroughly analyse all engineering steps which allow diversity to be introduced in systems programmed in these languages. Some new general problems are spotted and discussed as well. The second direction is dealing with version concurrency and distributedness in a general way. We investigate providing SFT by class diversity, which is the most general way of designing diverse software in OO systems. We concentrate on N-version programming (NVP) and give an exhaustive discussion of this approach. One of the main reasons for this choice is that we have come to believe that the general approach which allows a unified discussion of all SFT schemes is rather restrictive because it-does not properly address the differences between these schemes which represent their essences and the most difficult parts of their implementation and support. Our intention is to discuss the use of NVP in OO terms and to outline all novelties arising from this. The re-usability of SFT features is a key point in our approach. One of the conclusions we have arrived at is that, generally speaking, the entire states of version objects should be compared to defect and mask the faulty one. We propose unifying in one component features dealing with adjudication and faulty object recovery because these functionalities have a lot in common. Our approach is demonstrated using Ada 95. (C) 1999 Elsevier Science Inc. All rights reserved.
A zone envelope thermal model is derived from first principles, based on the exact two-port solution to the heat conduction equation. A single set of matrices, one for each frequency of interest, is used to describe t...
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A zone envelope thermal model is derived from first principles, based on the exact two-port solution to the heat conduction equation. A single set of matrices, one for each frequency of interest, is used to describe the thermal behaviour of the total envelope. The set of matrices must be computed once for a particular zone and cooling loads for various conditions, or the passive response, can then be obtained. The method is based on the same principles underlying the CTF method. However, the transfer function is calculated for the whole envelope by combining the two-port matrices of the individual walls, after simplification of the room interior heat transfer network. The conduction transfer coefficients of the individual walls forming the zone are not required. Except for the simplification of interior radiation, the method is completely exact and easy to implement. It is also numerically efficient. For load prediction, an implementation in the frequency domain, based on the prime factor FFT algorithm is convenient. For time domain simulation with active control, the envelope conduction coefficients are easily obtained by transforming to the Z-domain. This represents a modern solution of the envelope conduction problem, which is convenient to implement in modern objectoriented computer programming languages. 1998 Elsevier Science Ltd. All rights reserved.
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