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Optical Fiber Communication (OFC) Conference

作者： D.J. Blumenthal A. Carena L. Rau V. Curri S. Humphries Optical Communications and Photonic Networks Laboratory Department of Electrical and Computer Engineering University of California Santa Barbara CA USA Dipartimento di Automatica e Informatica Politecnico di Torino Torino Italy

ISBN: (纸本)155752582X

We believe we have demonstrated for the first time wavelength-division multiplexing (WDM) all-optical IP tag switching with wavelength conversion and subcarrier multiplexed addressing. Switching over four wavelengths covering 16 nm was demonstrated with noninverting wavelength conversion of 2.5 Gbps payloads and burst mode recovery of tag/headers.

关键词： Optical wavelength conversion Wavelength division multiplexing Technical Activities Guide -TAG Optical packet switching Optical filters Optical transmitters Optical receivers Optical interferometry Optical sensors Stimulated emission

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Classification tree models of software quality over multiple releases

Classification tree models of software quality over multiple...

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International Symposium on Software Reliability engineering (ISSRE)

作者： T.M. Khoshgoftaar E.B. Allen W.D. Jones J.I. Hudepohl Department of Computer Science and Engineering Empirical Software Engineering Laboratory Florida Atlantic University Boca Raton FL USA Business Unit of Nortel Networks EMERALD Research Triangle Park NC USA Florida Atlantic University Boca Raton FL USA

Software quality models are tools for focusing software enhancement efforts. Such efforts are essential for mission-critical embedded software, such as telecommunications systems, because customer-discovered faults have very serious consequences and are very expensive to repair. We present an empirical study that evaluated software quality models over several releases to address the question, "How long will a model yield useful predictions?" We also introduce the Classification And Regression Trees (CART) algorithm to software reliability engineering practitioners. We present our method for exploiting CART features to achieve a preferred balance between the two types of misclassification rates. This is desirable because misclassifications of fault-prone modules often have much more severe consequences than misclassifications of those that are not fault-prone. We developed two classification-tree models based on four consecutive releases of a very large legacy telecommunications system. Forty-two software product, process, and execution metrics were candidate predictors. The first software quality model used measurements of the first release as the training data set and measurements of the subsequent three releases as evaluation data sets. The second model used measurements of the second release as the training data set and measurements of the subsequent two releases as evaluation data sets. Both models had accuracy that would be useful to developers.

关键词： Classification tree analysis Software quality Predictive models Software measurement Training data Software tools Mission critical systems Embedded software Regression tree analysis Software algorithms

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An adaptive channel reservation scheme for soft handoff in cellular DS-CDMA systems

An adaptive channel reservation scheme for soft handoff in c...

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IEEE Conference on Vehicular Technology (VTC)

作者： J.W. Chang D.K. Sung J.H. Ahn J.H. Kim Communication Networks Research Laboratory Department of Electrical Engineering Korea Advanced Institute of Science and Technology South Korea Electronics and Telecommunications Research Institute South Korea Center for Advanced Computer Studies University of Southwestern Louisiana USA

In DS-CDMA systems, soft handoff techniques provide seamless connections of mobile call between cells. The reserved capacity for soft handoff calls is required to sufficiently support calls in a soft handoff region. However, since the capacity required by soft handoff calls varies according to environmental factors, the conventional fixed reserved capacity can be excessive if the required channel capacity by soft handoff calls is small and this may cause a considerable amount of unnecessary blocking of new calls. We propose an adaptive channel reservation scheme which reserves channel capacity as much act necessary according to the variation of soft handoff requests. A simulation result shows that the blocking probability of new coils is reduced by 33% compared with the conventional fixed channel reservation scheme and that it is even larger as the offered load decreases or the maximum reserved capacity increases.

关键词： Multiaccess communication Time division multiple access Frequency division multiaccess Channel capacity Interference Cellular networks Quality of service Intelligent networks Communication networks Laboratories

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Efficient Implementation of an Optimal Greedy Algorithm for Wavelength Assignment in Directed Tree networks

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ACM Journal of Experimental Algorithmics 1999年 4卷 4-4页

作者： Erlebach, Thomas Jansen, Klaus Computer Engineering and Networks Laboratory (TTK) ETH Zürich CH-8092 Zürich Gloriastrasse 35 Switzerland Institute for Computer Science and Applied Mathematics Christian-Albrechts-University of Kiel D-24098 Kiel Olshausenstr. 40 Germany

In all-optical networks with wavelength-division multiplexing several connections can share a physical link if the signals are transmitted on different wavelengths. As the number of available wavelengths is limited in practice, it is important to find wavelength assignments minimizing the number of different wavelengths used. This path coloring problem is NP-hard, and the best known polynomial-time approximation algorithm for directed tree networks achieves approximation ratio 5/3, which is optimal in the class of greedy algorithms for this problem. It is shown how the algorithm can be modified in order to improve its running-time to 0(T_ec(N,L)) for sets of paths with maximum load L in trees with N nodes, where T_ec(n,k) is the time for edge-coloring a k-regular bipartite graph with n nodes. An implementation of this efficient version of the algorithm in C++ using the LEDA class library is described, and experimental results regarding the running-times and the number of wavelengths used are reported. An additional heuristic that reduces the number of wavelengths used in the average case while maintaining the worst-case bound of 5L/3 is described. Categories and Subject Descriptors: F.2.2 [Analysis of Algorithms and Problem Complexity]: Nonnumerical Algorithms and Problems—Computations on discrete structures. © 1999, ACM. All rights reserved.

关键词： Algorithms bipartite edge coloring directed tree networks Experimentation Path coloring

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Preface

Lecture Notes in Computer Science (including subseries Lectu...

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Lecture Notes in computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 1999年 1700卷

作者： Stadler, Rolf Stiller, Burkhard Columbia University New York United States Center for Telecommunications Research Department of Electrical Engineering 500W 120th Street New York United States Swiss Federal Institute of Technology ETH Zuurich Computer Engineering and Networks Laboratory TIK Gloriastr. 35 ZuurichCH Switzerland

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The challenge of the global software process

The challenge of the global software process

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Workshops on Object-Oriented Technology, ECOOP 1997

作者： Murer, Tobias Computer Engineering and Networks Laboratory ETH Zuerich Switzerland

ISBN: (纸本)3540640398

The emerging technologies such as software components and the Internet challenge the way software is produced and marketed. The social, technical and organizational aspects of the software business will change significantly compared to the traditional understanding. Discussions about software components are often mainly limited to the technical aspects of interoperability. The purpose of this position paper is to motivate for a broader interdisciplinary discussion about components including technical aspects, but also organizational, social and even marketing aspects. We investigate these various aspects to develop the concept of a software engineering environment capable to face the outlined challenge. © Springer-Verlag Berlin Heidelberg 1998.

关键词： Commerce

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Access signaling and IN-based mobility management for wireless ATM systems

Access signaling and IN-based mobility management for wirele...

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IEEE International Conference on Universal Personal Communications, ICUPC 1998

作者： Loukas, Nikos H. Xenakis, Christos K. Merakos, Lazaros Venieris, Iakovos University of Athens Department of Informatics Communication Networks Laboratory Greece National Technical University of Athens Electrical and Computer Engineering Dept. Greece

ISBN: (纸本)0780351061

This paper focuses on the design of signaling and mobility control protocols for wireless ATM (W-ATM) systems based on the intelligent network (IN) concepts. The employed signaling protocol architecture aims for private W-ATM networks to access the core B-ISDN/ATM infrastructure. The proposed design intents to minimize the changes required to the wired ATM network signaling to accommodate mobility features, by taking advantage of the well-developed capability sets. A signaling performance evaluation is carried out to demonstrate the impact of the proposed signaling architecture onto various performance measures and to identify the behavior of the system under various signaling loads in order to reveal the limits of the signaling system stability. © 1998 IEEE.

关键词： Internet protocols

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Generation of Embedded Control Systems

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IFAC Proceedings Volumes 1998年第14期31卷 105-110页

作者： Ho. Trutmann Computer Engineering and Networks Laboratory TIK Swiss Federal Institute of Technology ETH CH-8092 Zurich Switzerland

The divergence between the development of the control system and its environment of technical devices in a complex new machine is difficult to handle and usually not addressed by existent development methods. The presented approach considers these questions and at the same time preserves the essential separation of functional and interface domains. Within each domain progress can be made independently using dedicated software tools. Generators provide implementations running with simulation models as well as partial or complete target implementations. The code is statically deterministic and runs in a simple environment with only a few processes. To confirm the real-time behavior of an implementation the generators also provide worst-case traces. Automatic code generation from models and specifications minimizes programming efforts and coding errors. The concept has been proven in a number of industrial and academic projects.

关键词： Embedded Systems Specifications Real-Time Control Automobile Control

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Accounting, charging, and pricing of communication services-an Internet-based exemplified study of influences

Accounting, charging, and pricing of communication services-...

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： B. Stiller Computer Engineering and Networks Laboratory TIK Swiss Federal Institute of Technology Switzerland

The most important approaches on Internet economics make various assumptions on pricing policies and services. This study introduces main reasonings for and against pricing as a method to reduce congestion of Internet services. These criteria encompass features of the economic model, the pricing mechanism, and the network model. Moreover necessary basics are outlined to handle general influences. Advantages and drawbacks of economics for communication services are discussed to reveal a structured picture of today's situation, which is driven by technological and economic factors at the same time. Based on a sketchy overview of related work a new volume-based approach for pricing communication services in the Internet is proposed and an implementation architecture is introduced.

关键词： Pricing Web and internet services IP networks Costs Protocols computer networks Electronic mail Economics Ground support High-speed networks

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ATM over shared media networks

ATM over shared media networks

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International Zurich Seminar on Broadband Communications

作者： G. Sidler B. Stiller C. Nadig B. Plattner Computer Engineering and Networks Laboratory TIK ETH Zürich Zurich Switzerland

The emerging asynchronous transfer mode (ATM) technology provides an end-to-end quality-of-service (QoS) for communication services. However within the local communication area traditionally stochastic network technology like Ethernet has been utilized. Therefore, an alternative approach to provide end-to-end ATM services without a complete replacement of traditional local area networking equipment, has been developed. ATM services are offered over Ethernet, where end-systems are attached via an Ethernet segment to an Ethernet-ATM attachment device (ASHMEN). Applications use common ATM signaling and ATM protocols, such as the ATM adaptation layer 5 (AAL 5) protocol, to setup and maintain end-to-end ATM connectivity. The developed protocol architecture includes a protocol mapping from AAL 5 frames into Ethernet frames which has been efficiently implemented in a UNIX-based workstation environment. QoS guarantees can be provided within the ATM network as usual and are offered additionally within the Ethernet segment which is made possible with Ethernet switching technology and a resource management module implemented in the Ethernet-ATM attachment device.

关键词： Asynchronous transfer mode Ethernet networks Protocols Local area networks Optical fiber LAN Quality of service Stochastic processes Resource management Communication networks Streaming media

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