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New algorithm for virtual path network design in ATM networks

Computer Communications 1999年第15期22卷 1481-1492页

作者： Panicker, K.K. Varghese Murthy, C. Siva Ram Mittal, R. Hewlett Packard India Software O. 560 052 Bangalore India Dept. of Comp. Sci. and Engineering Indian Inst. of Technology 600 036 Madras India Hughes Software Systems Electronics City 122 015 Gurgaon India

Virtual paths (VPs) in an ATM network form a logical network, called VP network (VPN), over the underlying physical network. VPN allows flexible management of network resources and hence its design is an important issue in designing an ATM network. In this paper, we consider the VPN design problem which is formulated as an optimization problem with the objective of minimizing the switching and transmission cost, and control and management cost. We present here, a two-phase heuristic solution for designing a good VPN for a given traffic demand. The first phase is a routing phase in which a route is found between every node pair in the network. In the second phase, paths are selected as VPs using the set of routes generated in the routing phase. A path is selected as a VP so as to minimize the following parameters: (i) the total number of VPs configured;(ii) the number of VPs carried by a link (load);and (iii) the VP hopcount, the number of VPs that are concatenated to form a virtual channel (VC). We study the performance of the proposed algorithm through extensive simulation on various networks. The results show that the VPN generated by the proposed algorithm is good in minimizing the number of VPs configured, the load on a link, and the VP hopcount. The comparison of the results obtained by the proposed algorithm and that of Ahn et al. shows that our algorithm performs better.

关键词： Asynchronous transfer mode

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Improved scheme for self-healing in ATM networks

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Computer Communications 1999年第15期22卷 1400-1414页

作者： Varghese Panicker, K.K. Siva Ram Murthy, C. Mittal, R. Hewlett Packard India Software O. 560 052 Bangalore India Dept. of Comp. Sci. and Engineering Indian Inst. of Technology 600 036 Madras India Hughes Software Systems Electronics City 122 015 Gurgaon India

A self-healing network can detect failures such as link/node failures and reroute the failed connections automatically using distributed control mechanisms. An improved scheme for self-healing in ATM networks based on the concept backup virtual path (VP) is presented. The objective of the backup VP problem is to find a backup VP for each of the working VPs so that the cost of providing the backup is minimized. A heuristic based solution for the backup VP routing problem using the concept of minimum cost shortest paths. Results showed that the proposed scheme are effective.

关键词： Asynchronous transfer mode

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Designing reusable object-oriented architectures - challenges, methods & tools

Designing reusable object-oriented architectures - challenge...

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technology of Object-Oriented Languages and systems (TOOLS)

作者： Kai Koskimies W. Pree J. Bosch G. Hedin Software Systems Laboratory Tampere University of Technology Tampere Finland Software Engineering Group University of Constance Constance Germany Department of Computer Science University of Karlskrona Ronneby Ronneby Sweden Department of Computer Science Lund University Lund Sweden

Summary form only given, as follows. More and more software developers are recognizing the need for solutions that make it possible to share code between different applications in the same domain. Reusing code increases not only the productivity of the developers but also the reliability and maintainability of the software products. Many software companies have ended up with a repository of enterprise components modelling the core business of the company, or with a product-line architecture that captures the common aspects of a family of software products. In both cases, object-orientation (OO) offers a technology that enables these solutions. The workshop studies the problems in designing reuse-oriented architectures (ROA) within the OO paradigm and the OO techniques that support this. The design of such systems is much harder than the design of individual applications, because ROAs need to be valid for unforeseen applications. Instead of a closed world of application concepts, the designer must analyze the variable aspects of a domain. The workshop covers a wide range of topics related to the development of ROAs, including: Design methods for OO product-lines/frameworks; Case studies of existing ROAs; Patterns and architectural styles supporting ROAs; Component-based ROAs; Evaluation of ROAs; Tools supporting the creation and reuse of product-line platforms and frameworks; Documentation of product-line platforms and frameworks; Practical experiences with reuse in OO; and Re-engineering legacy systems into ROAs.

关键词： software maintenance Computer architecture Application software Object oriented modeling Design methodology Documentation

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Constructing interoperable components in distributed systems

Constructing interoperable components in distributed systems

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technology of Object-Oriented Languages and systems (TOOLS)

作者： S. Ling H. Schmidt R. Fletcher School of Computer Science and Software Engineering Mohan University VIC Australia Cooperative Research Centre for Enterprise Distributed Systems Technology Mohan University VIC Australia

The separation of architecture definition language (ADL) and interface definition language (IDL) is widely accepted in the distributed system community. It separates issues of hierarchical composition and configuration from those of services, communication and synchronisation and thus eases reconfiguration without changing the interfaces and implementation and allows the change of services within well-defined configuration constraints. Our approach towards distributed system definition draws on the Darwin project's notion of distributed system architecture definition and on Eiffel's notion of design-by-contract. We extend contracts to deal with synchronisation and coordination at a higher level, explicitly targeting both large-scale loosely-coupled distributed components and tightly coupled parallel or multithreaded objects. In this paper we present a Java binding of the resulting contract extensions. We incorporate annotations into Java programs adding Eiffel-style assertions and other contractual constraints. Java component code and constraints are then associated to architectural diagrams in a visual programming environment. The paper illustrates the language features in a case study of a lift control system. Based on the case study, the component-based design approach is illustrated and the internal synchronisation of method execution is explained.

关键词： Contracts Java Concurrent computing Programming environments Read only memory Fault tolerance Protection Government

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Quantitative modeling of software reviews in an industrial setting

Quantitative modeling of software reviews in an industrial s...

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International Symposium on software Metrics

作者： O. Laitenberger M. Leszak D. Stoll K. El Emam Fraunhofer Institute of Experimental Software Engineering (IESE) Kaiserslautern Germany Lucent Technologies Network Systems GmbH Nuernberg Germany Institute for Information Technology National Research Council Ottawa ONT Canada

Technical reviews are a cost effective method commonly used to detect software defects early. To exploit their full potential, it is necessary to collect measurement data to constantly monitor and improve the implemented review procedure. This paper postulates a model of the factors that affect the number of defects detected during a technical review, and tests the model empirically using data from a large software development organization. The data set comes from more than 300 specification, design, and code reviews that were performed at Lucent's Product Realization Center for Optical Networking (PRC-ON) in Nuernberg, Germany. Since development projects within PRC-ON usually spend between 12% and 18% of the total development effort on reviews, it is essential to understand the relationships among the factors that determine review success. One major finding of this study is that the number of detected defects is primarily determined by the preparation effort of reviewers rather than the size of the reviewed artifact. In addition, the size of the reviewed artifact has only limited influence on review effort. Furthermore, we identified consistent ceiling effects in the relationship between size and effort with the number of defects detected. These results suggest that managers at PRC-ON must consider adequate preparation effort in their review planning to ensure high quality artifacts as well as a mature review process.

关键词： software reviews Computer industry Costs Monitoring software testing Programming Optical design Optical fiber networks Quality management Process planning

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Testing of concurrent programs after specification changes

Testing of concurrent programs after specification changes

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International Conference on software Maintenance (ICSM)

作者： In Sang Chung Hyeon Soo Kim Hyun Seop Bae Yong Rae Kwon Dong Gil Lee School of Information and Computer Engineering Hansung University South Korea School of Computer and Software Engineering Kum-Oh National University of Technology South Korea Department of Computer Science Korea Advanced Institute of Science and Technology South Korea Electronics and Telecommunications Research Institute South Korea

This paper describes a specification-based regression testing technique that can be applied for revalidating concurrent programs after specification changes. This kind of regression testing technique requires sequencing constraints which specify the precedence relations among synchronization events. In our method, the sequencing constraints are extracted automatically from Message Sequence Charts (MSCs) that are considered to be partial and nondeterministic specifications. We show how to identify the sequencing constraints affected by the modifications of a specification rather than creating new sequencing constraints from scratch to reduce the cost of regression testing. We also describe how to determine whether the affected sequencing constraints are satisfied by the program being tested.

关键词： Concurrent computing Telecommunication computing Costs Electronic equipment testing Read only memory Automatic testing Gas insulated transmission lines software testing Sequential analysis Error correction

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Transient analysis of minimum duration outage for RF channel in cellular systems

Transient analysis of minimum duration outage for RF channel...

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IEEE Conference on Vehicular technology (VTC)

作者： Yue Ma J.J. Han K.S. Trivedi Center for Advanced Computing and Communication (CACC) Department of Computer Science Duke University Durham NC USA Corporate Software Technology Center Schaumburg IL USA Center for Advanced Computing and Communication (CACC) Department of Electrical and Computer Engineering Duke University Durham NC USA

Following Mandayam et al. (1998), we define outage events as the channel being attenuated for at least a deterministic period of time, /spl tau//sub m/. Compared with a continuous time Markov chain or discrete time Markov chain, a semi-Markov process (SMP) is general enough that it allows the sojourn time to be any distribution function. In this paper, we develop a minimum duration outage model based on an SMP. Closed-form expressions are derived for the time dependent and steady state probabilities of outage. Describing the outage event in the transient regime, our model can reflect the channel fading behavior in a dynamic way.

关键词： Transient analysis Radio frequency Steady-state Markov processes Closed-form solution Fading Land mobile radio cellular systems Power system modeling Communication system software Computer science

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Car Type/Name Recognition System Based on The Concept of Fixation

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Journal of advanced Computational Intelligence and Intelligent Informatics 1999年第4期3卷 274-281页

作者： Arai, Yoshinori Hirota, Kaoru Research and Education Center of Software Engineering Tokyo Institute of Polytechnics 1583 Iiyama Kanagawa Atsugi243-0297 Japan Department of Computational lntelligence and Systems Science Interdisciplinary Graduate School of Science and Engineering Tokvo Institute of Technology 4259 Nagatsuta-cho Midori-ku Kanagawa Yokohama226-8502 Japan

The concept of the "Fixation", meaning to monitor features for identifying transport vehicles is proposed. And a framework of the "Fuzzy Hierarchical Pattern Recognition using a Fixation Feedback (FHPR/FF)" algorithm is introduced. The experiment system, for identifying car types and car names where 70 images are taken for 14 miniature cars from 5 directions, is constructed. Forced recognition of 92.9% is achieved for car types and 89.7% for car names. The proposed experiment system is the basis for real running vehicle identification confirmed by perfect identification of 5 images for each model. © 1999 Fuji technology Press. All rights reserved.

关键词： Fuzzy inference

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The redefinition of supportability and its role as a systems engineering tool

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NAVAL ENGINEERS JOURNAL 1999年第3期111卷 269-277页

作者： Blackwell, P Hausner, E Paul Blackwell:graduated in May 1985 from Michigan Technological University with a bachelor of science degree in electrical engineering. In Octover 1986 Paul took a position in inertial navigation engineering at the Naval took a position in inertial navigation engineering at the Naval Aviation Depot. Five years later he move to the Mission Software group where he worked developing tactical navigation software. W. Erich Hausner:is currently the Project Engineer—Producibility and Supportability Research. Erich's primary focus has been producibility and supportability research and life cycle cost analyses for various aircraft and space programs. He integrates producibility and supportability domain experts within systems engineering/design leads research and development in advanced producibility and supportability concepts and works with producibility and supportability engineers to define design. requirements. He developed the Knowledge-Aided Producibility/Supportability Analysis Technique (KPAT/KSAT). The International Society of Logistics awarded him with the prestigious Field Award for Concurrent Engineering and the Best Technical Paper—Acquisition and Support. He is a member of the Office of Naval Research—Best Manufacturing Practices—Producibility Task Force. He majored in physics at the New York Institute of Technology.

Reliability Centered Maintenance (RCM) is described as the cornerstone of time NAVAIR, NAVSEA, and SPAWAR Affordable Readiness Initiatives. However, many technical issues, which result in a significant impact to the Fleet's Readiness and Operations and Support Costs, are irrelevant to RCM analyses and are therefore overlooked. In addition, reliability and maintainability, parameters more suitable as a "figure of merit" in a laboratory environment, are used with fervor to analyze field data. This further compounds the ambiguity and diminishes the effectiveness of the RCM recommendations on readiness and cost In other words, using RCM "we are potentially stepping over dollars to save pennies." Supportability is traditionally thought of as a logistics metric related to the operational availability of a system. This paper redefines Supportability, describes the comprehensive Knowledge-Aided Supportability Analysis Technique (KSAT), and discusses how it can enhance the traditional metrics.

关键词： Decision support systems

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An Efficient Method for Version Control of a Tree Data Structure

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software: Practice and Experience 1999年第7期27卷

作者： ESTHER JINEE CHOI YONG RAE KWON Software Engineering Division System Engineering Research Institute P.O. Box 1 Yusong-gu Taejon 305-333 Korea Department of Computer Science Korea Advanced Institute of Science and Technology (KAIST) Korea

A new method for version controlling of a tree structure is presented. The key feature of the method is that the latest state of a tree is retained and other versions are constructed from it on request, and information on the change history of a node is maintaind in its parent node. Several algorithms for efficient manipulation of the tree have been developed, and it has been demonstrated that they correctly manipulate the tree. The performance of these algorithms has been compared with those of other tree-based methods, and found to be nearly optimal in all aspects of the comparison. © 1997 John Wiley & Sons, Ltd.

关键词： tree structure change management history version control

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