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Providing multiple views for objects

SOFTWARE-PRACTICE & EXPERIENCE 2000年第7期30卷 803-823页

作者： Minsky, NH Pal, PP BBN Technol Cambridge MA 02138 USA Rutgers State Univ Dept Comp Sci New Brunswick NJ 08903 USA

The need for multiple views of an object is often encountered in software practice. This paper presents our experience in addressing this need under a software architecture known as the law-governed architecture. We introduce the notion of a surrogate object which allows an object to appear different and behave differently when used from different parts of a system. This concept requires some minor modifications to the classical inheritance-based object-oriented systems, mostly involving a judicious use of delegation. A concrete implementation of surrogates under the law-governed architecture is described and some applications of surrogates are briefly discussed. Copyright (C) 2000 John Wiley & Sons, Ltd.

关键词： object-oriented modeling and frameworks surrogate objects delegation design patterns law-governed architecture access control

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object management for integrated design system of agricutural facilities

Object management for integrated design system of agricutura...

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2000 ASAE Annual International Meeting, Technical Papers: Engineering Solutions for a New Century

作者： Na, Joon-Yeop Kim, Han-Joong Lee, Jeong-Jae Seoul National University Suwon Korea Republic of Dept. of Agricultural Engineering Coll. of Agric. and Life Sciences Seoul National University Suwon 441-744 Korea Republic of

object-oriented and object-based technology is the predominant approach used to build integrated design systems. Effective use of object technology has demonstrated the ability to provide organizations with high-quality systems that are extremely understandable, maintainable and scaleable. Relational database management systems are the most prevalent implementation of back-end physical data stores for agricultural applications. They are frequently selected for persistent object storage and retrieval in object-relational systems. An object-oriented design may resemble a relational design. Usually this occurs only during the early conceptual phases of system development. However, as the design and implementation of the system matures, the goals of object-oriented and relational database development diverge. This divergence is caused because the objective of relational database development is to normalize data whereas the goal of object-oriented design is to model the problem domain as real-world objects. The result is an object-relational chasm. This paper presents an object manager for implementing object-relational systems in Integrated design System of Agricultural Facilities(IDSAF). It discusses a conceptual application and details of managing and mapping data in object to relational database.

关键词： Agriculture

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From design to implementation: Tool support for the development of object-oriented distributed real-time systems

From design to implementation: Tool support for the developm...

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12th Euromicro Conference on Real-Time systems

作者： Becker, LB Pereira, CE Univ Fed Rio Grande do Sul Inst Comp Sci BR-90000 Porto Alegre RS Brazil

ISBN: (纸本)0769507344

The increasing complexity in the development of real-time systems leads designers to make use of techniques that help handle the complexity. One method to deal with complexity that became popular in the last years is the use of the object-oriented paradigm. Some advances in hardware technology have made possible to overcome the overhead problems that prevented its adoption in the past. This paper describes an integrated software environment called SiMOO-RT, developed under the context of ADOORATA project(A Distributed object-oriented Architecture for Real-Time Automation), a Brazilian-German cooperation that guides designers to explore the whole phases of a real-time software development under the object-oriented paradigm. Here, the main features of the tool are presented and validated through means of a case study, and future directions of the project are highlighted.

关键词： Real time systems

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object-oriented modelling of spoken language dialogue systems

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Natural Language Engineering 2000年第3-4期6卷 33-40页

作者： McTEAR, Michael F. Faculty of Informatics University of Ulster Antrim BT37 OQB Newtownabbey United Kingdom

In this paper we show how established object modelling techniques can be used in the cre-ation of spoken dialogue management systems. One of the motivations behind the particular approach adopted here is the observation that, in spoken human-to-human dialogues, certain skillsets and patterns of dialogue evolution are common to many different contexts;other dialogue skills and accompanying real-world knowledge are required only for more specialised transactions within particular business domains. As a starting point for modelling an auto-mated spoken dialogue management system we recommend a use case analysis of the required functionality. The use case analysis encourages the developer to identify generic-specific relationships and interactions between different dialogue management skills. We consider some of the broad philosophies underlying current dialogue management systems and outline practical high-level dialogue behaviour based on mixed-initiative, frame-based processing, combined with a rigorously applied confirmation strategy. On the basis of the use case requirements analysis, we explore a possible design for an object-oriented dialogue management system, indicating the roles and relationships of the various classes that embody the required dialogue functionality, and showing how implemented objects within the system will interact. The man-ner of this interaction is such as to allow one overall system to process transactions in several business domains. We also indicate some of the advantages of a rule-based implementation: the proposed design is tailored towards such an implementation in Prolog++. An object-oriented development process places high-level, generic dialogue management functionality at the disposal of more specialised ‘expert’ components. Maintainability and extensibility are therefore enhanced: if the developer chooses to refine generic behaviour, it is immediately available to the more specialised components;if new domain-specific expertise

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Dynamic workflow management in CORBA distributed object systems

Dynamic workflow management in CORBA distributed object syst...

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5th International Symposium on Software Engineering for Parallel and Distributed systems (PDSE 2000)

作者： Tari, Z Pande, V Royal Melbourne Inst Technol Dept Comp Sci Melbourne Vic 3001 Australia

ISBN: (纸本)0769506348

We are beginning to see distributed dynamic workflow management systems being implemented using CORBA services. However these systems do not use events as the mechanism for co-ordinating workflows. Instead workflow components use messages to communicate with each other;thereby resulting in tightly coupled systems. We investigate the use of events as the co-ordinating mechanism for implementing dynamic event-based workflow solutions using existing CORBA services. This paper shows the limitations of the CORBA Event Service for dynamic workflow solutions based on a prototype implementation and proposes a more specialised Workflow Event Channel (WEC) that overcomes these limitations. A CORBA implementation of the WEC design enables event based workflow execution environments within a CORBA framework.

关键词： object oriented programming

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Knowledge-based predictive and reactive scheduling in industrial environments

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COMPUTERS & CHEMICAL ENGINEERING 2000年第9-10期24卷 2315-2338页

作者： Henning, GP Cerdá, J Univ Nacl Litoral INTEC CONICET RA-3000 Santa Fe Argentina

Real-world scheduling problems are intrinsically complex because of the dynamic nature of industrial environments, conflicting organizational goals, the existence of operational constraints and preferences that are difficult to represent in a computational model. In addition, plant capacity and bottleneck stages are generally not known ahead of time since they depend upon the product mixture. Therefore, rigid scheduling procedures, designed to provide optimal or near-optimal solutions under particular circumstances, will not always be satisfactory. Moreover, purely automatic scheduling is not realistic because it neglects the important role of the human expert, who has the ultimate responsibility for all decisions and wants to be engaged in the solution process. To overcome these difficulties, many authors have adopted knowledge-based approaches. This contribution presents a knowledge-based framework, based on the object oriented technology, for building scheduling systems aimed at solving real-world problems. The paper points out the most relevant aspects of the proposed framework architecture that supports both predictive and reactive scheduling. It has been designed to enhance the problem solving capabilities of human schedulers and has been abstracted after the successful implementation of three different scheduling systems, two of which have entered into everyday industrial use. The most important lessons that were learned during the design of these systems are outlined in the paper. (C) 2000 Elsevier Science Ltd. All rights reserved.

关键词： short-term scheduling knowledge-based systems object-oriented technology

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3D mapping of an interactive synthetic environment

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COMPUTER 2000年第3期33卷 35-+页

作者： Ladner, R Abdelguerfi, M Shaw, K USN Res Lab Stennis Space Ctr MS 39529 USA Univ New Orleans New Orleans LA 70148 USA

Traditional geospatial information systems (GIS) use geographically referenced data to produce highly accurate digital maps. These two-dimensional maps include well-recognized symbols that represent features such as mountains, forests, buildings, and transportation networks. Although this flat view provides an excellent means of orienting the user to the general nature and location of the geographic features for a given area, it does not provide the full experiential value that comes from immersion within a 3D environment. The authors, working in conjunction with the University of New Orleans' Computer Science Department, developed a 3D-GIS to assist the US Marine Corps with mission preparation and rehearsal. It also provides on-site awareness during actual field operations in urban areas. Going beyond presenting stereoscopic views of an area or merely applying photo textures to highly simplified geometric shapes, they created an environment that replicates its real-world counterpart by including detailed 3D objects. The article details the design considerations they faced as well as the implementation and structural overview for the entire system.

关键词： Buildings object oriented databases Information systems Geographic Information systems Shape Windows Floors object oriented modeling Transportation Laboratories

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Building a large-scale generic object model: Applying the CYC upper ontology to object database development in Java

Building a large-scale generic object model: Applying the CY...

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2000 Conference on object-oriented Programming, systems, Languages, and Applications, OOPSLA 2000

作者： Strom, Stephen FGM Inc. 45245 Business Court Dulles VA 20166 United States

ISBN: (纸本)1581133073

Can the benefits of re-use and patterns that are so well known in software design and implementation be carried over into analysis and database design? The fledgling field of Analysis Patterns has provided only a partial affirmative answer. We have instead attempted to import the CYC upper ontology (an AI-derived model of everything) into an object model expressed in Java. The result is an object model that is extremely resilient to change and should be extensible to practically any domain. We describe the difficulties involved and some of the most important lessons learned. © 2000 ACM.

关键词： object-oriented databases

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object oriented database for a GIS

Object oriented database for a GIS

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2nd International Conference on Management Information systems Incorporating GIS and Remote Sensing (MIS 2000)

作者： Posada, N Sol, D Univ Americas Puebla CENTIA Cholula Mexico

ISBN: (纸本)1853128155

This paper describes the design and implementation of geographic data in an object/relational database. Infomix Universal Server (IUS) is a tool that permits the description of persistent geographic objects. The geographic objects were designed by using the OMT methodology. The application was built with the Java programming language. The objects were made persistent, by using the IUS database management system. A web user interface was developed to show the geographic data. Data modeling was done by using points, lines, polylines and polygons. The data stored in the database could be exported and used by a client who runs a web user interface. Our representation gives the description to have an homogeneous geographic data representation to be used in a geographic database server. The user can then access and use the data stored in the database. The web user interface runs on the client and the database manager runs on the server. The object oriented geographic databases that use a standard representation are the first step to build tools that will permit the interoperability of heterogeneous GIS.

关键词： Geographic information systems

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Schedulability analysis and automated implementation of real-time object-oriented design models.

Schedulability analysis and automated implementation of real...

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作者： Karvelas, Panagiota. Concordia University

学位级别：Master

There is a growing interest in adopting object technologies for the development of real-time systems. Several commercial tools, currently available, provide object-oriented modeling and design support for real-time systems. While these products provide many useful facilities, such as visualization tools and automatic code generation, they are all weak in addressing the central characteristic of real-time system design, i.e., providing support for a designer to reason about timeliness properties.;We believe an approach that integrates the advancements in both object modeling and design methods, and real-time scheduling theory is the key to successful use of object technology for real-time software. We propose a methodology based on this idea for uni-processor multi-threaded environments. Specifically, given an application design model and end-to-end timing requirements, we synthesize a feasible implementation model using a built-in schedulability analysis tool. The synthesis process is supported by automatic code generation that can take the application design model and the synthesized implementation model and generate code for the target platform.;In this thesis, I have designed and implemented some of the key components to support this methodology. First, I have developed a schedulability test that determines whether a particular implementation model satisfies the real-time requirements of an application. This can be used during the automatic synthesis process. Second, I have developed an initial implementation supporting automatic code generation, which takes textual specifications of the application design model and a synthesized implementation model, and automatically generates executable code for it.

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