This paper proposes a methodology to solve contingency load transfer of distribution systems by applying the object-oriented expert system. By this method, the faulted area is isolated and restored and the unfaulted, ...
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This paper proposes a methodology to solve contingency load transfer of distribution systems by applying the object-oriented expert system. By this method, the faulted area is isolated and restored and the unfaulted, but out of service, area is restored effectively. Since the fault restoration has to be performed in a short time period and the affected area has to be constrained in a small area, it has become a critical issue to enhance the system reliability for the distribution system operation. The knowledge rule base with object-oriented programming can be designed to support distribution contingency management in an effective manner. The distribution facilities are designed as a class in the database and the distribution operation rules are created to form the knowledge base. To demonstrate the effectiveness of the proposed method, one of the Taipower distribution systems is selected for computer simulation. It is concluded that the contingency load transfer of distribution systems can be solved efficiently by identifying the proper switching operation to solve the distribution contingency problem. (C) 1997 Elsevier Science S.A.
The burden of organizational learning surrounding software process innovations (SPIs)-and complex organizational technologies in general-creates a ''knowledge barrier'' that inhibits diffusion. Attewel...
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The burden of organizational learning surrounding software process innovations (SPIs)-and complex organizational technologies in general-creates a ''knowledge barrier'' that inhibits diffusion. Attewell (1992) has suggested that many organizations will defer adoption until knowledge barriers have been sufficiently lowered;however, this leaves open the question of which organizations should be more likely to innovate, even in face of high knowledge barriers. It is proposed here that organizations will innovate in the presence of knowledge barriers when the burden of organizational learning is effectively lower, either because much of the required know-how already exists within the organization, or because such knowledge can be acquired more easily or more economically. Specifically, it is hypothesized that organizations will have a greater propensity to initiate and sustain the assimilation of SPIs when they have a greater scale of activities over which learning costs can be spread (learning-related scale), more extensive existing knowledge related to the focal innovation (related knowledge), and a greater diversity of technical knowledge and activities (diversity). An empirical study using data on the assimilation of object-oriented programming languages (OOPLs) by 608 information technology organizations strongly confirmed the importance of the three hypothesized factors in explaining the assimilation of OOPLs.
An object-oriented scheduling system for a job-shop manufacturing cell has been developed and tested. A powerful optimization technique based on genetic algorithms was used to improve the routing of subassembly parts ...
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An object-oriented scheduling system for a job-shop manufacturing cell has been developed and tested. A powerful optimization technique based on genetic algorithms was used to improve the routing of subassembly parts in the manufacturing cell. The scheduling system is composed of three interactive modules: the due date algorithms, the genetic algorithms, and the manufacturing cell simulator. These modules exchange information to accomplish 'genetic optimization' and to fulfill time-dependent and technological constraints simultaneously, using a composite objective function. The due date algorithms use the production sequences and processing times of individual parts of a single product to generate production priorities. The genetic algorithms module creates a population of feasible machine routings and schedules, and passes it on to the manufacturing cell simulator. The manufacturing cell simulator performs the production plans under different scheduling configurations. The genetic algorithms module uses the fitness value of each scheduling alternative progressively to improve the production schedule until a convergence criterion is satisfied. (C) 1997 Elsevier Science B.V.
A project to develop a new system, Core Master 2, was undertaken in Sweden in 1990. This is a relatively large system, for nuclear power plant core engineering. Main project goals were to increase end-user productivit...
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A project to develop a new system, Core Master 2, was undertaken in Sweden in 1990. This is a relatively large system, for nuclear power plant core engineering. Main project goals were to increase end-user productivity while reducing user-induced errors and software life-cycle costs. To meet them and improve software quality, object-oriented technology was adopted. The software process became much slower than expected. Learning aspects related to the new technology and changing specifications account for most of the delay. The first version is now ready and is being shipped to customers. Lessons learned from the process, education and training are discussed.
This paper is concerned with the software development of distributed real-time measurement systems. Major gears are modularity, reusability and independency from hardware devices, processors and comunications networks...
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This paper is concerned with the software development of distributed real-time measurement systems. Major gears are modularity, reusability and independency from hardware devices, processors and comunications networks. A light-weight architecture for real-time (DART) is proposed which delivers a systematic methodology centred on object-oriented techniques. The effectiveness of DART is illustrated by means of its application to a distributed measurement system for electrical power plants. (C) 1997 Elsevier Science B.V.
The BQM-an acronym that stands for Bottom-up Query machine, the role played by our system in the framework of the KIWIS system [2]-system extends deductive database technology with knowledge structuring capabilities t...
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The BQM-an acronym that stands for Bottom-up Query machine, the role played by our system in the framework of the KIWIS system [2]-system extends deductive database technology with knowledge structuring capabilities to provide an advanced environment for the development of data and knowledge-based applications. The system relies on a knowledge representation language that combines the declarativeness of logic programming with the notions of object, inheritance with exceptions, and message passing. Exceptions are supported by allowing rules with negated heads. The use of exceptions inside the inheritance mechanism makes the language inherently nonmonotonic. The paper contains a comprehensive description of both the language and the implementation principles of the BQM system. It begins by providing a model-theoretic semantics of the language based on the notion of least model. A fixpoint semantics, providing a constructive definition of the least model, is given as well. Then, a number of implementation techniques for efficient query evaluation are described. Such techniques significantly extend ''traditional'' deductive database query evaluation strategies to deal with monotonic reasoning. A description of the architecture of the current prototype of the BQM system is also given.
An intelligent real-time system has been developed to monitor greenhouse sensor signals. Its objective is to detect and correct errors in the data due to faulty sensor readings. The system (FLASH-Flexible Artificial I...
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An intelligent real-time system has been developed to monitor greenhouse sensor signals. Its objective is to detect and correct errors in the data due to faulty sensor readings. The system (FLASH-Flexible Artificial Intelligence for Signal Handling in real time) uses a novel knowledge-based approach for fault detection and isolation. It comprises three modules: Scheduler, Signal Processing and Reasoning which communicate via a Blackboard. FLASH has been implemented in C++ on a Sun Workstation running Solaris 2 and it was demonstrated using real-time data. Copyright (C) 1997 Elsevier Science Ltd.
This paper presents a new modelling architecture and a formal modelling approach based on concepts derived from object-oriented programming. It also presents the conclusions of a comparative study of the methods used ...
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This paper presents a new modelling architecture and a formal modelling approach based on concepts derived from object-oriented programming. It also presents the conclusions of a comparative study of the methods used for numerical and formal solutions. The architecture and the approach that are described here have been applied to a complex real system: modelling the road behaviour of vehicles - articulated or not. Copyright (C) 1997 Elsevier Science Ltd.
An object-oriented message-passing class library in C++, called PPI++, for portable parallel programming has been developed. PPI++ (parallel portability interface in C++) is designed to serve as a stable (unchanging) ...
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An object-oriented message-passing class library in C++, called PPI++, for portable parallel programming has been developed. PPI++ (parallel portability interface in C++) is designed to serve as a stable (unchanging) interface between the client parallel code and the rapidly evolving distributed computing environments. By taking advantage of encapsulation, inheritance, and polymorphism supported by C++, PPI++ provides a clean and consistent programming interface, which helps improve the clarity and expressiveness of client parallel codes and hides implementation details and complexity from the user to ease parallel programming tasks. In addition, the use of strong type-checking in C++ allows the detection of potential misuses of the library at compile time, and thus promotes code reliability. This paper describes the object-oriented design and implementation of PPI++. Evaluation of PPI++ on important performance issues, such as portability, ease-of-use, extensibility, and efficiency, is also discussed.
Many languages for computer systems simulation (like GPSS and CSim) use a stochastic model of systems with the provision of adding procedural code for those aspects of the system that cannot be captured easily by a st...
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Many languages for computer systems simulation (like GPSS and CSim) use a stochastic model of systems with the provision of adding procedural code for those aspects of the system that cannot be captured easily by a stochastic model. However, they do not support the hierachical simulation of complex systems well. Complex computer systems may have to be simulated at various levels of abstraction in the interests of tractability: the flexibility of being able to freely move between the different levels of abstraction is very desirable. For example, in the area of computer architecture, one might have analytical models, detailed simulation models and trace-driven models. In addition, these languages do not have user-friendly interfaces for specification of the simulated system. In this paper, we discuss the design and implementation of a simulation package for hierachical simulation of non-real-time computer systems: a Simulator Generator from a Graphical System Specification (SIGGSYS). A new language for system specification has been designed. In addition, the package has the following components: A graphical user interface to aid specification of the system to be simulated. A rear end that generates C++ code that implements a simulator for the specified system. A complete object library along with the header files that implement a functionally complete set of C++ base classes which can be built upon. C++ has been chosen as the intermediate language so that the modeller can use its support for objectorientedprogramming. (C) 1997 John Wiley & Sons, Ltd.
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