Knowledge-based CASE tools are able to play an active part in the design of computer-based systems. Providing such tools with in-built domain-specific (or 'real world') knowledge can enhance both the performan...
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Knowledge-based CASE tools are able to play an active part in the design of computer-based systems. Providing such tools with in-built domain-specific (or 'real world') knowledge can enhance both the performance and the appearance of intelligence. However, little work has so far been carried out as to how this might be achieved. The paper illustrates how such knowledge may be provided in the form of generic models based on a thesaurus approach, and applies the technique to a knowledge-based CASE tool designed to support object-oriented design.
A multilayer neural network development environment, called ANNDE, is presented for implementing effective learning algorithms for the domain of engineering design using the object-oriented programming paradigm. It co...
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A multilayer neural network development environment, called ANNDE, is presented for implementing effective learning algorithms for the domain of engineering design using the object-oriented programming paradigm. It consists of five primary components: learning domain, neural nets, library of learning strategies, learning process, and analysis process. These components have been implemented as five classes in two object-oriented programming languages C++ and G++. The library of learning strategies includes generalized delta rule with error backpropagation. Several examples are presented for learning in the domain of structural engineering.
We focus on using object-oriented techniques to improve the hardware design process. The advantages of these techniques for hardware design include: improved modifiability and maintainability of models; easy component...
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We focus on using object-oriented techniques to improve the hardware design process. The advantages of these techniques for hardware design include: improved modifiability and maintainability of models; easy component instantiation with different parameters; quick composition of new components; the ability to identify and reuse common components; the ability to tailor general-purpose components to more specialized components; support of dynamic object creation and destruction; and the possibility of employing existing software synthesis and verification techniques. We illustrate the application of object-oriented techniques using a load-store, reduced instruction-set processor that contains a local memory. The instruction set consists of 22 instructions, which require one or two 16-bit words. Arithmetic is performed in two's complement. We use C++ to demonstrate the usefulness of object-oriented techniques, not to provide arguments for or against its use in hardware modeling and design
This paper presents a mechanism that facilitates and enhances the use of independently administered remote network servers in the presence of server interface heterogeneity. The mechanism is designed under the client-...
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This paper presents a mechanism that facilitates and enhances the use of independently administered remote network servers in the presence of server interface heterogeneity. The mechanism is designed under the client-service model, which extends the client-server model with an abstraction of service to decouple abstract server capabilities from concrete server interface specifics such as server interface binding protocols and the interface operation invocation protocols. The mechanism selects servers, accommodates server interface heterogeneity, and handles server access failures as per the abstract server capabilities desired by the client. It could return the identity of the server used for each service access invocation to facilitate billing, refining service specifications, and reporting server-specific errors. This paper also illustrates a C library interface to this mechanism, and describes a language veneer over the C programming language demonstrating bow a typed procedural language could be extended by a few language constructs to support the mechanism under the client-service model. In this language, server capabilities are referenced by abstract data type (ADT) objects, and are accessed by invoking the objects' interface operations using a call-by-value-result paradigm. This language veneer also makes it easier to port the client software across to systems that use different service specification schemes. Our work suggests that this mechanism facilitates the development, use, and maintenance of client and server software in large heterogeneous distributed systems comprising many autonomous servers. It also shows that the overhead of invoking remote server operations via the mechanism can be quite low.
The object-oriented programming environment Smalltalk is used to implement a tool for modeling and simulation of ecological systems. This PC-based tool makes it possible, and easy, to represent individuals explicitly ...
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The object-oriented programming environment Smalltalk is used to implement a tool for modeling and simulation of ecological systems. This PC-based tool makes it possible, and easy, to represent individuals explicitly in the simulation of ecological systems. This PC-based tool makes it possible, and easy, to represent individuals explicitly in the simulation, and to integrate the individual-based approach with a traditional population/concentration-based approach. object-oriented programming is used to allow for an efficient development of models. The properties of Smalltalk are exploited to make testing and investigation of the models occur interactively, supported by a user-friendly interface. In the paper, modeling and simulation concepts and elements of object-oriented programming as they relate to an individual-based approach, are introduced. The simulation extension in question (EcoTalk) is described. Two applications that make use of EcoTalk are presented, both related to population-dynamics. The discussion centers on practical implications of the approach, e.g. the system characteristics that can be expressed in EcoTalk. An indication of the performance of an application is given. It is concluded that, at present, EcoTalk can be used for medium-sized applications.
This article gives a detailed presentation of constraint satisfaction in the hybrid LAURE language. LAURE is an object-oriented language for Artificial Intelligence (AI) applications that allows the user to combine ru...
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This article gives a detailed presentation of constraint satisfaction in the hybrid LAURE language. LAURE is an object-oriented language for Artificial Intelligence (AI) applications that allows the user to combine rules, constraints, and methods that cooperate on the same objects in the same program. We illustrate why this extensibility is necessary to solve some large and difficult problems by presenting a real-life application of LAURE. We describe the syntax and the various modes in which constraints may be used, as well as the tools that are proposed by LAURE to extend constraint resolution. The resolution strategy as well as some implementation details are given to explain how we obtain good performances.
MOON is a design method suitable for real-time systems that supports concurrency and asynchronous communication. A MOON design specifies the structure of the software system, the hardware resources and the allocation ...
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MOON is a design method suitable for real-time systems that supports concurrency and asynchronous communication. A MOON design specifies the structure of the software system, the hardware resources and the allocation of software components to hardware resources. Performance evaluation is very important throughout the development of a real-time system. Program resource mapping nets (PRM-Nets) are a timed Petri net formalism used for performance evaluation studies. PRM-Nets are integrated performance models recognising the influence of the software structure, physical resources and mapping between software elements and physical resources on performance. Simulation of PRM-Nets allows estimates of response time, throughout and resource utilisation for a variety of hardware configurations to be investigated. The paper proposes the use of PRM-Nets for performance evaluation studies during a MOON design. The transformation of MOON activities and IDAs to PRM-Net performance models is outlined, and the modelling of hardware resources is considered.
Conventional object-oriented design methodologies lead to a hierarchy of classes, but do not suggest which classes/objects should be loaded on which processors in a distributed system. We present the Decomposition Cos...
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Conventional object-oriented design methodologies lead to a hierarchy of classes, but do not suggest which classes/objects should be loaded on which processors in a distributed system. We present the Decomposition Cost Evaluation Model (DCEM) as an approach to this problem. DCEM brings the mapping problem to a higher level of abstraction where the question is which classes, rather than which tasks, should be loaded on which processors. To support these decisions we define communication and computation cost functions for objects, classes, and hierarchies. We then introduce Confined Space Search Decomposition (CSSD) which enhances parallel operations of applications utilizing a tree topology for the processor interconnection scheme. To reduce the penalties of load imbalance, we include a distributed dynamic load balancing heuristic called object Reincarnation (OR) in which no additional communication costs are incurred.
Paragon is a notation for specifying object behaviours using sets of rewrite rules, where rewriting is controlled by synchronous and asynchronous message passing, and where objects may be dynamically created as a rewr...
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Paragon is a notation for specifying object behaviours using sets of rewrite rules, where rewriting is controlled by synchronous and asynchronous message passing, and where objects may be dynamically created as a rewriting side-effect. This paper overviews Paragon, and introduces a simple classification scheme for analysis of Paragon specifications. Restrictions on specifications are discussed in consideration of implementation feasibility and efficiency constraints. Implementation schemes based on the analysis and restrictions are defined. In particular, a translation strategy for static systems is detailed and motivated with a worked example. To reinforce the low-level nature of the derived implementation the translation is defined in terms of a digital hardware description language. Schemes for the implementation of general dynamic systems are also considered.
In this paper, we describe the traffic simulation system which analyzes a traffic flow in a road network. The system is constructed and operated on the parallel computer AP1000. A database of a road network is impleme...
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In this paper, we describe the traffic simulation system which analyzes a traffic flow in a road network. The system is constructed and operated on the parallel computer AP1000. A database of a road network is implemented with the object-oriented programming technique. Elements of a road network are regarded as objects, and vehicles which move on the lanes are regarded as attributive data. The database is divided into sub-databases and assigned to each processor. The system calculates the behavior of vehicles in parallel, Sending and receiving data among the objects are carried out with message passing on the communication network, Moreover, we show the results of the vehicles behavior, and evaluate the parallel efficiency.
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