检索结果-内蒙古大学图书馆

International Workshop on Research Issues in Data engineering

作者： V. Crestana-Taube E.A. Rundensteiner Department of Elect. Engineering and Computer Science Software Systems Research Laboratory University of Michigan Ann Arbor MI USA

We have developed the transparent schema evolution (TSE) system that, simulating schema evolution using object-oriented views, allows for the interoperability of applications with diverse and even changing requirements. TSE relieves users of the risk of making existing application programs obsolete when run against the modified schema, because the old view schema is maintained while a new view schema is generated to capture the changes desired by the user. However TSE may be generating a large number of schema versions (object-oriented view schemata) over time, resulting in an excessive build-up of classes and underlying object instances-some of which may potentially no longer be in use. We propose to solve this problem by developing techniques for effective and consistent schema removal. First, we characterize four potential problems of schema consistency that could be caused by removal of a single virtual class; and then outline our solution approach for each of these problems. Second, we demonstrate that view schema removal is sensitive to the order in which individual classes are processed. Our solution to this problem is the development of a dependency graph model for capturing the class relationships, used as a foundation for selecting among removal sequences. Designed to optimize the performance of the TSE system by effective schema version removal, the proposed techniques will enable more effective interoperability among evolving software applications.

关键词： Application software Object oriented modeling computer science software systems Laboratories Computational modeling Marine vehicles Design optimization software performance Veins

来源：评论

学校读者我要写书评

暂无评论

ASPECT-an Architecture SPECification Technique a report on work in progress

ASPECT-an Architecture SPECification Technique a report on w...

引用

International Conference and Workshop on engineering of computer-Based systems

作者： V. Kirova W. Rossak Department of Computer and Information Science Department of Computer and Information Science New Jersey Institute of Technology Newark NJ USA Department of Computer and Information Science Department of Computer and Information Science Software and Systems Engineering Laboratory New Jersey Institute of Technology Newark NJ USA

We discuss ASPECT, a first step towards a generic specification technique for software architectures. We present and discuss an abstract grammar for ASPECT that lists and relates to each other all the architectural elements that form ASPECT's vocabulary. After elaborating on the characteristics of these architectural elements, we illustrate their application in a small example.

关键词： computer architecture software systems systems engineering and theory Laboratories software architecture Information science Open systems Costs Decision support systems Standardization

来源：评论

学校读者我要写书评

暂无评论

Virtual memory versus file interfaces for large, memory-intensive scientific applications 96

Virtual memory versus file interfaces for large, memory-inte...

引用

Proceedings of the 1996 ACM/IEEE conference on Supercomputing

作者： Yoonho Park Ridgway Scott Stuart Sechrest High Performance Computing Center University of Houston Houston TX Software Systems Research Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI

ISBN: (纸本)9780897918541

Scientific applications often require some strategy for temporary data storage to do the largest possible simulations. The use of virtual memory for temporary data storage has received criticism because of performance problems. However, modern virtual memory found in recent operating systems such as Cenju-3/DE give application writers control over virtual memory policies. We demonstrate that custom virtual memory policies can dramatically reduce virtual memory overhead and allow applications to run out-of-core efficiently. We also demonstrate that the main advantage of virtual memory, namely programming simplicity, is not lost.

关键词： custom policies

来源：评论

学校读者我要写书评

暂无评论

Incorporation of relational modeling method into object-oriented analysis

Incorporation of relational modeling method into object-orie...

引用

IEEE International Conference on Communications (ICC)

作者： Chung-Horng Lung J.E. Urban G.T. Mackulak Software Engineering Analysis Laboratory Nortel Technologies Inc. Ottawa ONT Canada Department of Computer Science Arizona State University Tempe AZ USA Systems Simulation Laboratory Industrial & Management Systems Engineering Arizona State University Tempe AZ USA

It is a generally accepted concept that multiple views are needed in object-oriented analysis or domain analysis techniques. Three commonly adopted models for requirements analysis include object model, functional model and dynamic model. This paper introduces and incorporates the concept of relational modeling into the analysis techniques. Relational modeling mainly deals with two tasks: classification of semantic relations and identification of higher-order system causal relations. Classification of semantic relations supports comparison and evaluation of various relations, which in turn can be used to select suitable methods to process the relations. A higher-order relation depicts the relations between different relations as opposed to the relations between objects often discussed in object modeling. A network of higher-order relations reveals the cause-effect dependency relationships and can facilitate understanding and reasoning of application systems. Furthermore, incorporation of relational modeling techniques can support software reuse in an application domain or across domains.

关键词： Object oriented modeling Application software Lungs computer science Computational modeling Analytical models computer simulation Laboratories Seals software engineering

来源：评论

学校读者我要写书评

暂无评论

Virtual Memory versus File Interface for Large, Memory-Intensive Scientific Applications

Virtual Memory versus File Interface for Large, Memory-Inten...

引用

Supercomputing Conference

作者： Yoonho Park R. Scott S. Sechrest High performance computing center University of Houston Houston TX USA Software Systems Research Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

关键词： Memory Operating systems Control systems

来源：评论

学校读者我要写书评

暂无评论

Implementation of a discretionary access control model for script-based systems

Implementation of a discretionary access control model for s...

引用

computer Security Foundations Workshop

作者： T. Jaeger A. Prakash Software Systems Research Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

Powerful applications can be implemented using command scripts. A command script is a program written by one user, called a writer, and made available to another user, called the reader, who executes the script. For instance, command scripts could be used by Mosaic, the popular World-wide Web browsing tool, to provide fancy interfaces to services, such as banking, shopping, etc. However, the use of command scripts presents a serious security problem. A command script is run with the reader's access rights, so a writer can use a command script to gain unauthorized access to the reader's data and applications. Existing solutions to the problem either severely restrict I/O capability of scripts, limiting the range of applications that can be supported, or permit all I/O to scripts, potentially compromising the security of the reader's data. We define a discretionary access control model that permits users to flexibly limit the access rights of the processes that execute a command script. We use this model in a prototype system that safely executes command scripts available from Mosaic.

关键词： Access control Permission Postal services Power system modeling File systems Data security software systems Laboratories Electronic mail Application software

来源：评论

学校读者我要写书评

暂无评论

Materialized object-oriented views in MultiView

Materialized object-oriented views in MultiView

引用

International Workshop on Research Issues in Data engineering

作者： H.A. Kuno E.A. Rundensteiner Department of Electrical Engineering and Computer Science Software Systems Research Laboratory University of Michigan Ann Arbor MI USA

Object-oriented view mechanisms have received much attention in the literature in recent years, since they provide powerful mechanisms for addressing tasks such as customized tool interfacing to object-oriented databases (OODBs) and interoperability of heterogeneous databases. However, little progress has been made thus far on addressing the topic of view materialization in object-oriented databases. In the context of the MultiView project, we have developed an object model and an accompanying set of algorithms for the support of updatable materialized views in OODBs. We take advantage of unique features of the MultiView model, including its support for object-preserving queries, the integration of base and virtual classes into a unified and consistent global class hierarchy, and an object-slicing approach. In this paper, we present the MultiView model of materialized views, supporting updates on both base and virtual classes. We also describe a set of efficient algorithms for incremental view maintenance.< >

关键词： Object oriented modeling Object oriented databases computer science software systems Spatial databases Context modeling NASA Prototypes

来源：评论

学校读者我要写书评

暂无评论

A transparent object-oriented schema change approach using view evolution

A transparent object-oriented schema change approach using v...

引用

International Conference on Data engineering

作者： Young-Gook Ra E.A. Rundensteiner Department of Electrical Engineering and Computer Science Software Systems Research Laboratory University of Michigan Ann Arbor MI USA

When a database is shared by many users, updates to the database schema are almost always prohibited because there is a risk of making existing application programs obsolete when they run against the modified schema. This paper addresses the problem by integrating schema evolution with view facilities. When new requirements necessitate schema updates for a particular user, the user specifies schema changes to the personal view rather than to the shared base schema. Our view evolution approach then computes a new view schema that reflects the semantics of the desired schema change, and replaces the old view with the new one. We present algorithms that implement the set of schema evolution operations typically supported by OODB systems as view definitions. This approach provides the means for schema change without affecting other views (and thus without affecting existing application programs). The persistent data is shared by different views of the schema, i.e., both old as well as newly developed applications can continue to interoperate. In this paper, we present examples that demonstrate our approach.< >

关键词： Object oriented databases Multimedia databases computer science software systems Electronic mail Application software Data models computer aided manufacturing CADCAM Multimedia systems

来源：评论

学校读者我要写书评

暂无评论

PROGRAM VIEW GENERATION AND CHANGE ANALYSIS USING ATTRIBUTED DEPENDENCY GRAPHS

引用

JOURNAL OF software MAINTENANCE-RESEARCH AND PRACTICE 1995年第4期7卷 239-261页

作者： ALZOUBI, R PRAKASH, A Software Systems Research Laboratory Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI 48109-2122 U.S.A. He is currently an Assistant Professor at Yarmouk University Irbed H.K. of Jordan. Earlier he has worked for the Ford Motor Company in Dearborn Michigan. His research interests are in the area of software engineering. Since 1989 he has been with the Department of Electrical Engineering and Computer Science at the University of Michigan Ann Arbor where he is currently an Associate Professor. His research interests include software engineering and computer-supported cooperative work. He is a member of the ACM and the IEEE Computer Society.

software maintenance is usually the most expensive phase of the software life-cycle, Program understanding and impact-of-change analysis are two of the major activities during this phase, In this paper, we describe attributed program dependency graphs (APDGs), a model to store information derived from the program source code and ease construction of tools for software maintenance, We show how the model can be used for interactive view generation and doing two kinds of impact-of-change analysis-incremental and comparison-oriented. Incremental change analysis uses APDGs and a Rule Base to provide a way for the user to analysis the effect of proposed well-defined changes, Comparison-oriented change analysis allows a user to generate structural semantic differences between two versions of a subsystem after an arbitrary sequence of changes, We also introduce SCAN, a prototype collection of loosely integrated tools based on the APDG model and describe our experiences with the system.

关键词： PROGRAM REPRESENTATION DEPENDENCY GRAPHS PROGRAM UNDERSTANDING REVERSE-engineering REengineering IMPACT ANALYSIS CHANGE ANALYSIS

来源：评论

学校读者我要写书评

暂无评论

PARALLEL AND DISTRIBUTED TLM COMPUTATION WITH SIGNAL-PROCESSING FOR ELECTROMAGNETIC-FIELD MODELING

引用

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1995年第3-4期8卷 169-185页

作者： SO, PPM ESWARAPPA, C HOEFER, WJR NSERC/MPR Teltech Research Chair in RF Engineering Department of Electrical and Computer Engineering University of Victoria Victoria British Columbia V8W 3P6 Canada Poman So received his B.Sc. degree in computer science and physics from the University of Toronto Toronto Onatario Canada in 1985. He obtained his B.A. Sc. and M.A.Sc. degrees in electrical engineering (summa cum laude) from the University of Ottawa Ottawa Ontario Canada in 1987 and 1989 respectively. Mr So was a research engineer in the University of Ottawa from January 1989 to October 1991 his research interests included CAD techniques of microwave circuits and numerical methods for electromagnetic wave modelling. He specialized in the development of electromagnetic engineering CAD software and successfully implemented a number of electromagnetic wave simulators based on the two-dimensional and three-dimensional transmission-line matrix methods. From August 1990 to February 1991 he accompanied Professor W. J. R. Hoefer to Rome Italy and Sophia Antiopolas France. During that time he implemented a parallel version of the 3D-TLM simulator for the CM-2 Connection Machine using C-Star and X Windows Library. He is a research engineer and a Ph.D. student at the University of Victoria Victoria British Columbia Canada. He ported the 2D- and 3D-TLM simulators to DECmpp 1200 massively parallel computer using MPL C and C++. He also combined OSA90/hope a commercially available microwave CAD program with a 2D-TLM simulation module for geometry optimization using the Datapipe technique of OSA90/hope. Recently he has developed a distributed client-server computing technique for the TLM method this technique could accelerate the TLM simulation by more than an order of magnitude. Channabasappa Eswarappa received the M.Tech. degree in electrical engineering from the Indian Institute of Technology Kanpur India in 1983 and Ph. D. degree from the University of Ottawa Canada in 1990. He worked as an Assistant Executive Engineer and later as

This paper describes the implementation of transmission-line matrix (TLM) method algorithms on a massively parallel computer (DECmpp 12000), the technique of distributed computing in the UNIX environment, and the combination of TLM analysis with Prony's method as well as with autoregressive moving average (ARMA) digital signal processing for electromagnetic field modelling. By combining these advanced computation techniques, typical electromagnetic field modelling of microwave structures by TLM analysis can be accelerated by a few orders of magnitude.

关键词： Mathematical models

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：