检索结果-内蒙古大学图书馆

Routing and wavelength assignment vs. wavelength converter placement in all-optical networks

IEEE communications Magazine 2003年第8期41卷 S22-S28页

作者： Li, Bo Chu, Xiaowen Sohraby, Kazem Computer Science Department Hong Kong Univ. of Sci. and Technol. Hong Kong Hong Kong Computer Science Department College of Engineering University of Arkansas Fayetteville AR United States

Blocking has been the key performance index in the design of an all-optical network. Existing research demonstrates that an effective routing and wavelength assignment strategy and a proper wavelength converter placement algorithm are the two primary vehicles for improving the blocking performance. However, these two issues have largely been investigated separately in that the existing RWA algorithms have seldom considered the presence of wavelength conversion, while the wavelength converter placement algorithms have largely assumed that a static routing and random wavelength assignment algorithm is employed. The main objective of this article is to present some strong evidences that these two issues need to be considered jointly, and call for the reexamination of both RWA and wavelength converter placement.

关键词： optical communication

来源：评论

学校读者我要写书评

暂无评论

Using genetic algorithms to optimize the behaviour of adaptive multimedia applications in wireless and mobile scenarios

Using genetic algorithms to optimize the behaviour of adapti...

引用

IEEE conference on Wireless communications and networking

作者： P.M. Ruiz A.F. Gomez-Skarmeta Research and Development Department Agora Systems S. A. Madrid Spain Department Information Engineering Communications Facultad de Informtica University of Murcia Murcia Spain

Adaptive applications are a key concept to take into account when dealing with multimedia internetworking in wireless and mobile environments in which abrupt changes in the network conditions may occur. In these scenarios not all the problems in the multimedia quality are due to congestion, as it happens in fixed networks, but also to interference, mobility, and many other issues. This paper presents an adaptation architecture allowing applications to use adaptation techniques at the application layer to minimize the impact of adverse and changing network conditions. This allows maintaining the QoS perceived by the user in an acceptable level. In addition, we optimize the adaptive behavior using genetic algorithms to estimate the optimal triggers for the adaptation function. We present some results comparing the fitness of using such adaptive techniques against the traditional multimedia internetworking.

关键词： Genetic algorithms Wireless networks Bandwidth Streaming media Internetworking Interference Radio link Multimedia systems Research and development Mobile communication

来源：评论

学校读者我要写书评

暂无评论

communication performance issues for two cluster computers 03

Communication performance issues for two cluster computers

引用

Proceedings of the 26th Australasian computer science conference - Volume 16

作者： Francis A. Vaughan Duncan A. Grove Paul D. Coddington Department of Computer Science University of Adelaide Adelaide SA 5005 Australia

ISBN: (纸本)9780909925949

Clusters of commodity machines have become a popular way of building cheap high performance parallel computers. Many of these designs rely on standard Ethernet networks as a system interconnect. We have profiled the performance of some standard message passing communication on commodity clusters using MPIBench, a tool for benchmarking the performance of MPI routines that uses a highly accurate, globally synchronised clock. The results suggest that existing methodologies of performance characterisation are inadequate. Tests were performed on two clusters, one with a conventional network architecture of switches connected via a high bandwidth backbone, the other with a tetrahedral network topology that potentially provides for lower contention and higher bandwidth. Where packet loss does not occur, performance in either system is good and degrades smoothly with load. However, packet loss is found to occur at any load and the consequent invocation of the TCP/IP timeout and congestion control mechanisms affect performance to a much greater than expected level. The nature of many parallel programs causes overall performance to drop to the worst case rather than the average. The value of MPIBench in profiling communication in parallel systems is clearly demonstrated, particularly through its generation of probability distributions which allow detailed analyses of performance problems.

关键词： communication networks cluster computing MPI bench-marking performance analysis parallel computing

来源：评论

学校读者我要写书评

暂无评论

issues concerning usability of 802.11 networks for real-time service transport

Issues concerning usability of 802.11 networks for real-time...

引用

IEEE Region 8 International Symposium on Video/Image Processing and Multimedia communications (EURASIP)

作者： D. Kedmenec V. Kedmenec M. Gerencir Verso Mrezne Tehnologije Zagreb Croatia

There has been a considerable expansion of alternative, VOIP based enterprise telephony networks in recent years. These networks have introduced stable and flexible cores that can be used to accommodate traffic from diverse set of edge applications. One of the newer developments in the access part of the network is introduction of wireless Ethernet as a medium that enables mobility and flexibility in accessing the network. Such a network can be used to enable access to all of the existing applications including real-time voice. However, the nature of the wireless medium and the way in which such access network is built requires special consideration when trying to use it for real-time traffic. Careful design can lead to a network that can be used for such a purpose, using standards based components. In order to properly design wireless access network, nature of real-time traffic needs to be examined.

关键词： Usability Quality of service communication system traffic control Internet telephony Ethernet networks Wireless networks Real time systems communication standards Multiprotocol label switching Access protocols

来源：评论

学校读者我要写书评

暂无评论

Performance evaluation of wavelength band switching in multifiber all-optical networks

Performance evaluation of wavelength band switching in multi...

引用

IEEE Annual Joint conference: INFOCOM, IEEE Computer and communications Societies

作者： X. Cao Vishal Anand Y. Xiong C. Qiao Department of Computer Science and Engineering State University of New York University at Buffalo Buffalo USA

Wavelength band switching (WBS) has only recently attracted attention from the optical networking industry for its practical importance in reducing the control complexity and cost of optical cross-connects (OXCs). However, WBS-related problems of theoretical interest have not been addressed thoroughly by the research community, and many issues are still wide open. In particular, WBS is different from wavelength routing, and thus techniques developed for wavelength-routed networks (including e.g., those for traffic grooming) cannot be directly applied to effectively address WBS-related problems. In this paper, we first propose a new multigranular OXC (MG-OXC) architecture for WBS, which is more flexible than any existing WBS node architectures. We also adopt the most powerful waveband assignment strategy, and develop an efficient heuristic algorithm called Balanced Path routing with Heavy-Traffic first (BPHT). To verify its near-optimality, we also develop an integer linear programming (ILP) model. Both the ILP and the BPHT algorithms can handle the case with multiple fibers per link and hence are more general than our previous single-fiber solutions X. Cao et al. (2002). We conduct a comprehensive evaluation of the benefits of WBS through detailed analysis and simulations. We show that the proposed heuristic BPHT can perform much better than a heuristic which applies the optimal routing and wavelength assignment (RWA) method. We also show that WBS using BPHT is even more beneficial in multifiber networks than in single-fiber networks in terms of reducing the port count. Our analytical and simulation results also provide valuable insights into the effect of wavelength band granularity, as well as the trade-offs between the wavelength-hop and the port count required in WBS networks.

关键词： all-optical networks optical fiber networks Wavelength routing Analytical models Industrial control optical control Costs communication system traffic control Heuristic algorithms Integer linear programming

来源：评论

学校读者我要写书评

暂无评论

Webit: a minimum and efficient Internet server for non-PC devices

Webit: a minimum and efficient Internet server for non-PC de...

引用

IEEE conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： Guang-jie Han Hai Zhao Jin-dong Wang Tao Lin Ji-yong Wang School of information science & Engineering Northeastern University Shenyang China

ISBN: (纸本)0780379748

The greatest benefit of Webit is without a doubt that it enables a standard connection to non-PC devices using the Internet. Since the use of Webit opens a new method for maintaining and supervising non-PC devices, it has become a helpful tool for users to control and manage devices remotely. Webit actualizes the connection between non-PC devices and Internet, thus all kinds of devices around us may be controlled and accessed over the Internet through a standard Web browser. In this paper, we introduce the reasons that why provide Internet connectivity for non-PC devices. We present the architecture of Webit that can support Internet connectivity for non-PC devices. We also present how to design and implement it and finally compare the results of Webit's performance and other similar Internet servers.

关键词： Internet Web server IP networks network servers TCPIP communication system control Costs Real time systems Information science Maintenance engineering

来源：评论

学校读者我要写书评

暂无评论

Scaling issues in robot-based sensing missions

Scaling issues in robot-based sensing missions

引用

IEEE Instrumentation and Measurement Technology conference

作者： M. Siegel The Robotics Institute Carnegie Mellon University Pittsburgh PA USA

Scaling analysis provides a systematic way to translate the performance of a system from one size domain, operating environment, etc., to another. In this paper, we identify scaling issues and present some simple results in the domain of individual mobile robots, as well as teams, swarms, etc., deployed on sensing missions. Since most robot-based sensing missions anticipate mini-, micro-, and nano-scale robots, our explicit examples focus on scaling-down of existing human-scale robot design and concepts. However the principles articulated apply equally to scaling-up situations. The topic is introduced via a simple example that shows why scaling-down of mobile robots that carry their own energy source will generally prove impractical: to obtain reasonable operating times it will rather be necessary to develop small robots into which energy can be beamed, or which can forage for energy sources in the environment. From this concrete illustrative example, the paper moves on to a higher level discussion of robot architecture and the applicability of scaling principles, to varying degrees, to all the modules, i.e., it is not exclusively a mobility issue. There follows a short discussion of how changes of scale are not inherently problematic, but to the contrary, in many cases suitable scale change provides the key to solving a difficult engineering problem. The final section is a quantitative example in which design and operating parameters of the robotic nodes of a sensor network are considered from the perspective of operating time limited by the energy cost of node-to-node communication. This example powerfully illustrates a system in which fairly modest changes contemplated range of engineering parameters result in enormous changes in the anticipated operating time of the system.

关键词： Robot sensing systems Mobile robots Power engineering and energy Batteries Performance analysis Concrete Costs Zoology Friction Energy consumption

来源：评论

学校读者我要写书评

暂无评论

Gemini:: An optical interconnection network for parallel processing

引用

IEEE TRANSACTIONS ON PARallEL AND DISTRIBUTED systems 2002年第10期13卷 1038-1055页

作者： Chamberlain, RD Franklin, MA Baw, CS Washington Univ Comp & Commun Res Ctr St Louis MO 63130 USA Airvana Inc Chelmsford MA 01824 USA

The Gemini interconnect is a dual technology (optical and electrical) interconnection network designed for use in tightly-coupled multicomputer systems. It consists of a circuit-switched optical data path in parallel with a packet-switched electrical control/data path. The optical path is used for transmission of long data messages and the electrical path is used for switch control and transmission of short data messages. This paper describes the architecture of the interconnection network and related communications protocols. Fairness issues associated with network operation are addressed and a discrete-event simulation model of the entire system is described. network performance characteristics derived from the simulation model are presented. The results show significant performance benefits when using virtual output queuing and quantify the tradeoffs between throughput and fairness in the system.

关键词： optical communication multiprocessor interconnection networks fair scheduling protocols performance evaluation

来源：评论

学校读者我要写书评

暂无评论

optical MEMS in optical networks 28

Optical MEMS in optical networks

引用

28th European conference on optical communication, ECOC 2002

作者： Ryf, Roland Photonic Subsystems Research Department Bell Laboratories Lucent Technologies HolmdelNJ United States

optical micromachines are positioned as an enabling technology for the next generation of optical line systems. The MEMS-based optical crossconnect is a scalable platform to enable the next generation of mesh-based ne... 详细信息

ISBN: (纸本)8790974638

关键词： network architecture

来源：评论

学校读者我要写书评

暂无评论

Next generation information communication infrastructure and case studies for future power systems

Next generation information communication infrastructure and...

引用

作者： Qiu, Bin Virginia Polytechnic Institute and State University

学位级别：Ph.D.

As power industry enters the new century, powerful driving forces, uncertainties and new functions are compelling electric utilities to make dramatic changes in their information communication infrastructure. Expanding network services such as real time measurement and monitoring are also driving the need for more bandwidth in the communication network. These needs will grow further as new remote real-time protection and control applications become more feasible and pervasive. This dissertation addresses two main issues for the future power system information infrastructure: communication network infrastructure and associated power system applications. optical networks no doubt will become the predominant data transmission media for next generation power system communication. The rapid development of fiber optic network technology poses new challenges in the areas of topology design, network management and real time applications. Based on advanced fiber optic technologies, an all-fiber network is investigated and proposed. The study will cover the system architecture and data exchange protocol aspects. High bandwidth, robust optical networks could provide great opportunities to the power system for better service and efficient operation. In the dissertation, different applications are investigated. One of the typical applications is the SCADA information accessing system. An Internet-based application for the substation automation system will be presented. VLSI (Very Large Scale Integration) technology is also used for one-line diagrams auto-generation. High transition rate and low latency optical network is especially suitable for power system real time control. In the dissertation, a new local area network based Load Shedding controller (LSC) for isolated power system will be presented. By using PMU (Phasor Measurement Unit) and fiber optic network, an AGE (Area Generation Error) based accurate wide area load shedding scheme will also be proposed. The objective is

关键词：

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：