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SRAT-distribution voltage sags and reliability assessment tool

IEEE TRANSACTIONS ON POWER DELIVERY 2004年第2期19卷 738-744页

作者： Koner, P Ledwich, G Queensland Univ Technol Sch Elect & Elect Engn Brisbane Qld 4001 Australia Queensland Elect Transmiss & Distribut Sch Elect & Elect Engn Brisbane Qld 4001 Australia

Interruptions to supply and sags of distribution system voltage are the main aspects causing customer complaints. There is a need for analysis of supply reliability and voltage sag to relate system performance with network structure and equipment design parameters. This analysis can also give prediction of voltage dips, as well as relating traditional reliability and momentary outage measures to the properties of protection systems and to network impedances. Existing reliability analysis software, often requires substantial training, lacks automated facilities, and suffers from data availability. Thus it requires time-consuming manual intervention for the study of large networks. A user-friendly sag and reliability assessment tool (SRAT) has been developed based on existing impedance data, protection characteristics, and a model of failure probability. The new features included in SRAT are a) efficient reliability and sag assessments for a radial network with limited loops, b) reliability evaluation associated with realistic protection and restoration schemes, c) inclusion of momentary outages in the same model as permanent outage evaluation, d) evaluation of the sag transfer through meshed subtransmission network, and e) simplified probability distribution model determined from available faults records. Examples of the application of the tools to an Australian distribution network are used to illustrate the application of this model.

关键词： network reliability object-oriented programming power distribution power quality

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Intelligent real-time fault diagnosis of greenhouse sensors

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CONTROL ENGINEERING PRACTICE 1997年第11期5卷 1573-1580页

作者： Beaulah, SA Chalabi, ZS Silsoe Research Institute Wrest Park Silsoe Bedford MK45 4HS UK

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.

关键词： intelligent knowledge-based systems fault detection sensor failures reasoning realtime object-oriented programming

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On evaluation of shape sensitivities of non-linear critical loads

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2003年第6期56卷 809-846页

作者： Parente, E Vaz, LE Univ Fed Pernambuco Dept Civil Engn BR-50740530 Recife PE Brazil Pontificia Univ Catolica Rio de Janeiro Dept Civil Engn Rio De Janeiro Brazil

The present paper focuses on the evaluation of the shape sensitivities of the limit and bifurcation loads of geometrically non-linear structures. The analytical approach is applied for isoparametric elements, leading to exact results for a given mesh. Since this approach is difficult to apply to other element types, the semi-analytical method has been widely used for shape sensitivity computation. This method combines ease of implementation with computational efficiency, but presents severe accuracy problems. Thus, a general procedure to improve the semi-analytical sensitivities of the non-linear critical loads is presented. The numerical examples show that this procedure leads to sensitivities with sufficient accuracy for shape optimization applications. Copyright (C) 2002 John Wiley Sons, Ltd.

关键词： shape sensitivity analysis structural optimization non-linear structures object-oriented programming

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SteamTables: An approach of multiple variable sets

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COMPUTERS & GEOSCIENCES 2009年第10期35卷 2145-2150页

作者： Verma, Mahendra P. Inst Invest Elect Cuernavaca 62490 Morelos Mexico

Using the IAPWS-95 formulation, an ActiveX component SteamTablesIIE in Visual Basic 6.0 is developed to calculate thermodynamic properties of pure water as a function of two independent intensive variables: (1) temperature (T) or pressure (P) and (2) T, P, volume (V), internal energy (U), enthalpy (H), entropy (S) or Gibbs free energy (G). The second variable cannot be the same as variable 1. Additionally, it calculates the properties along the separation boundaries (i.e., sublimation, saturation, critical isochor, ice I melting, ice III to ice IIV melting and minimum volume curves) considering the input parameter as T or P for the variable 1. SteamTablesIIE is an extension of the ActiveX component SteamTables implemented earlier considering T (190 to 2000 K) and P (3.23 x 10(-8) to 10000 MPa) as independent variables. It takes into account the following 27 intensive properties: temperature (T), pressure (P), fraction, state, volume (V), density (Den), compressibility factor (Z(o)), internal energy (U), enthalpy (H), Gibbs free energy (G), Helmholtz free energy (A), entropy (S), heat capacity at constant pressure (C(p)), heat capacity at constant volume (C(v)), coefficient of thermal expansion (CTE), isothermal compressibility (Z(iso)), speed of sound (VelS), partial derivative of P with T at constant V (dPdT), partial derivative of T with V at constant P (dTdV), partial derivative of V with P at constant T (dVdP), Joule-Thomson coefficient (JTC), isothermal throttling coefficient (IJTC), viscosity (Vis), thermal conductivity (ThrmCond), surface tension (SurfTen), Prandtl number (PrdNum) and dielectric constant (DielCons). (C) 2009 Elsevier Ltd. All rights reserved.

关键词： SteamTables Water PVT characteristics object-oriented programming Visual Basic 6.0 IAPWS-95 formulation

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Design and implementation of an OLE for process control unified architecture aggregating server for a group of flexible manufacturing systems

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IET SOFTWARE 2011年第4期5卷 406-414页

作者： Girbea, A. Nechifor, S. Sisak, F. Perniu, L. Transylvania Univ Brasov Dept Automat Fac Elect Engn & Comp Sci Brasov 500174 Romania PSE Siemens Romania Corp Technol Brasov 500007 Romania

The article focuses on the development of an OPC UA (object linking and embedding (OLE) for process control unified architecture) server. One of the major concerns regarding this new specification is the migration from the old component object model (COM) to the new UA specification. From the various migration strategies described in this article, the authors' server represents a special adapter software solution which aggregates several COM servers, one for each flexible manufacturing system (FMS) modelled in the address space of the UA server. The article focuses on the advantages introduced by the new specification like the unified modelling capability and the extensible meta model. The address space is exemplified by means of a screw fitting station, which is part of the flexible line, on which the UA server has been tested. From the four generally accepted use cases, the server implements the first two: observation and control. They are mainly supported through the variables and the methods of the address space. During the testing phase, the minimum sampling interval regarding the communication with the underlying COM servers has been determined for a different number of FMSs. As a result the special adapter software solution is a fast but also a well-performing approach, which works well even in very complex environments.

关键词： unified modelling capability OPC UA COM server object linking and embedding process control Control engineering computing Unified Modeling Language Industrial applications of IT flexible manufacturing system Production engineering computing unified architecture aggregating server extensible meta model software architecture Manufacturing systems Formal methods screw fitting station component object model flexible manufacturing systems FMS modelling adapter software solution Distributed systems software OLE for process control object-oriented programming distributed object management

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DEVELOPMENT OF THE object-oriented FINITE-ELEMENT MODELING SYSTEM - MODIFY

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ENGINEERING WITH COMPUTERS 1993年第4期9卷 187-197页

作者： OHTSUBO, H KAWAMURA, Y KUBOTA, A UNIV TOKYO CTR ENGNBUNKYO KUTOKYO 113JAPAN

In this paper we present a new concept of FE modeling, based on the object-oriented principle, and develop the prototype progam MODIFY (MODeling tool for Integrated Finite element analysis). MODIFY has three novel features: (1) FE modeling by the part object concept, (2) a fully object-oriented data structure, and (3) a part-by-part Sully automated mesh subdivision. When using MODIFY it is necessary to define and assemble part objects, which consist of geometry objects, analytical condition objects and relation objects, to describe the continuity between adjacent part objects. MODIFY automatically generates an appropriate FE model for each geometry object, satisfying continuity conditions with adjacent parts by referring to relation objects. If some part of the model is to be modified, the user needs only to change the corresponding part objects. Because of the object-oriented data structure, MODIFY also has a powerful capability for adaptive meshing. The existing version of MODIFY is applicable to FE models for 3-D shell structures.

关键词： CAD FEM MESH GENERATION MODELING object-oriented programming

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A new visual package for design and simulation of desalination processes

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DESALINATION 2006年第1-3期194卷 281-296页

作者： Nafey, A. S. Fath, H. E. S. Mabrouk, A. A. Suez Canal Univ Fac Petr & Min Engn Dept Engn Sci Suez Egypt Univ Alexandria Fac Engn Dept Mech Engn Alexandria Egypt

A visual design and simulation package was developed for design and simulation of different types and configurations of desalination processes. object-oriented programming with Visual Basic was used to offer a flexible reliable and friendly user-interface. The desalination plant components (named here as units), such as heat exchangers, flash chambers, evaporators, pumps, steam ejector, compressor, reverse osmosis membrane, pipes, etc., are stored as icons in a visual library. This visual library enables the user to construct different configurations by just clicking the mouse over the required units (icons). The interface aids both plant designers, operators and other users to perform different calculations such as energy, exergy, and thermoeconomics. In addition, the package enables designers to perform different modifications of an existing plant or to develop a conceptual design for new configurations. The present package offers great help not only to the designers and operators but also to researchers, educators and students. Some operating desalination plants were simulated with the package to show its reliability and flexibility. Typical desalination processes such as multistage flash, multi-effect evaporation, thermal vapor compression, mechanical vapor compression and reverse osmosis were simulated to show the wide scope and great capability of the package.

关键词： desalination object-oriented programming sparse matrix process simulation

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Metamorphic programmig: Unconventional high performance

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COMPUTER 2004年第3期37卷 30-+页

作者： Maurer, PM Baylor Univ Waco TX 76798 USA

Metamorphic programming solves common computing problems with sometimes spectacular performance gains over conventional coding. Although these programs violate good programming rules, a few minor compiler enhancements... 详细信息

关键词： discrete event simulation software performance evaluation VLSI circuitsimulation object-oriented programming logic simulation metamorphic programming performance simulation times benchmarks logic-level VLSI circuit simulation mainstream high-level languages

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On the notion of inheritance

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ACM COMPUTING SURVEYS 1996年第3期28卷 438-479页

作者： Taivalsaari, A Nokia Research Center Helsinki Finland

One of the most intriguing-and at the same time most problematic-notions in object-oriented programming is inheritance. Inheritance is commonly regarded as the feature that distinguishes object-oriented programming from other modern programming paradigms, but researchers rarely agree on its meaning and usage. Yet inheritance is often hailed as a solution to many problems hampering software development, and many of the alleged benefits of object-oriented programming, such as improved conceptual modeling and reusability, are largely credited to it. This article aims at a comprehensive understanding of inheritance, examining its usage, surveying its varieties, and presenting a simple taxonomy of mechanisms that can be seen as underlying different inheritance models.

关键词： delegation incremental modification inheritance language constructs object-oriented programming programming languages

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Apportioning: A technique for efficient reachability analysis of concurrent object-oriented programs

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IEEE TRANSACTIONS ON SOFTWARE ENGINEERING 2001年第11期27卷 1037-1056页

作者： Iyer, S Ramesh, S Indian Inst Technol Sch Informat Technol Powai 400076 Mumbai India Indian Inst Technol Dept Comp Sci Bombay 400076 Maharashtra India

The object-oriented paradigm in software engineering provides support for the construction of modular and reusable program components and is attractive for the design of large and complex distributed systems. Reachability analysis is an important and well-known tool for static analysis of critical properties in concurrent programs, such as deadlock freedom. It involves the systematic enumeration of all possible global states of program execution and provides the same level of assurance for properties of the synchronization structure in concurrent programs, such as formal verification. However, direct application of traditional reachability analysis to concurrent object-oriented programs has many problems, such as incomplete analysis for reusable classes (not safe) and increased computational complexity (not efficient). We have proposed a novel technique called apportioning, for safe and efficient reachability analysis of concurrent object-oriented programs, that is based upon a simple but powerful idea of classification of program analysis points as local (having influence within a class) and global (having possible influence outside a class). Given a program and a classification of its analysis points, reachability graphs are generated for 1) an abstract version of each class in the program having only local analysis points and 2) an abstract version of the whole program having only global analysis points. The error to be checked is decomposed into a number of subproperties, which are checked in the appropriate, reachability graphs. Different choices for the classification of analysis points, provide the flexibility to have many algorithms that are safe and efficient for different subclasses of programs. We have developed a number of apportioning-based algorithms, having different degrees of safety and efficiency. In this paper, we present the details of one of these algorithms, formally show its safety for an appropriate class of programs, and present experimental

关键词： concurrent programs object-oriented programming static analysis reachability analysis

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