检索结果-内蒙古大学图书馆

Seamless TCP Migration on Smartphones without network Support

IEEE TRANSACTIONS ON MOBILE COMPUTING 2014年第3期13卷 678-692页

作者： Rahmati, Ahmad Shepard, Clayton Tossell, Chad C. Zhong, Lin Kortum, Philip Nicoara, Angela Singh, Jatinder Broadcom Corp Sunnyvale CA 94086 USA Rice Univ Houston TX 77005 USA USAF Res Lab Wright Patterson AFB OH 45433 USA Deutsch Telekom Silicon Valley Innovat Ctr Mountain View CA 94043 USA Stanford Univ Stanford CA 94305 USA

Is it possible to migrate TCP/IP flows between different networks on modern mobile devices without infrastructure support or protocol changes? To answer this question, we make three research contributions: 1) We report a comprehensive characterization of IP traffic on 27 iPhone 3GS users for three months. 2) Driven by these findings, we devise two simple, effective, and easily deployable system mechanisms to support seamless flow migration without network support, and extensively evaluate their effectiveness using our field collected traces of real-life usage. Wait-n-Migrate leverages the fact that most flows are short lived. It establishes new flows on newly available networks but allows preexisting flows on the old network to terminate naturally. Resumption Agent takes advantage of the resumption functionality of modern protocols to securely resume flows without application intervention. Combined, they provide an unprecedented opportunity to immediately deploy policies that leverage multiple networks to improve the performance, efficiency, and connectivity of mobile devices. 3) We report an iPhone-based implementation of these system mechanisms and demonstrate their overhead to be negligible. Furthermore, we employ a sample switching policy, AutoSwitch, to demonstrate their performance. Through traces and field measurements, we show that AutoSwitch reduces user disruptions by an order of magnitude.

关键词： Mobile computing network architecture and design user/machine systems

来源：评论

学校读者我要写书评

暂无评论

Distributed Clustering With Directional Antennas for Wireless Sensor networks

引用

IEEE SENSORS JOURNAL 2013年第6期13卷 2166-2180页

作者： Chen, Ying-Chih Wen, Chih-Yu Natl Chung Hsing Univ Grad Inst Commun Engn Dept Elect Engn Taichung 402 Taiwan

This paper proposes a decentralized algorithm for organizing an ad hoc sensor network into clusters with directional antennas. The proposed autonomous clustering scheme aims to reduce the sensing redundancy and maintain sufficient sensing coverage and network connectivity in sensor networks. With directional antennas, random waiting timers, and local criterions, cluster performance may be substantially improved and sensing redundancy can be drastically suppressed. The simulation results show that the proposed scheme achieves connected coverage and provides efficient network topology management.

关键词： Distributed systems network architecture and design sensor networks

来源：评论

学校读者我要写书评

暂无评论

Subscriber Assignment for Wide-Area Content-Based Publish/Subscribe

引用

IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2012年第10期24卷 1833-1847页

作者： Yu, Albert Agarwal, Pankaj K. Yang, Jun Duke Univ Dept Comp Sci Levine Sci Res Ctr Durham NC 27708 USA

We study the problem of assigning subscribers to brokers in a wide-area content-based publish/subscribe system. A good assignment should consider both subscriber interests in the event space and subscriber locations in the network space, and balance multiple performance criteria including bandwidth, delay, and load balance. The resulting optimization problem is NP-complete, so systems have turned to heuristics and/or simpler algorithms that ignore some performance criteria. Evaluating these approaches has been challenging because optimal solutions remain elusive for realistic problem sizes. To enable proper evaluation, we develop a Monte Carlo approximation algorithm with good theoretical properties and robustness to workload variations. To make it computationally feasible, we combine the ideas of linear programming, randomized rounding, coreset, and iterative reweighted sampling. We demonstrate how to use this algorithm as a yardstick to evaluate other algorithms, and why it is better than other choices of yardsticks. With its help, we show that a simple greedy algorithm works well for a number of workloads, including one generated from publicly available statistics on Google Groups. We hope that our algorithms are not only useful in their own right, but our principled approach toward evaluation will also be useful in future evaluation of solutions to similar problems in content-based publish/subscribe.

关键词： network architecture and design wide-area networks

来源：评论

学校读者我要写书评

暂无评论

Scalable Localization with Mobility Prediction for Underwater Sensor networks

引用

IEEE TRANSACTIONS ON MOBILE COMPUTING 2011年第3期10卷 335-348页

作者： Zhou, Zhong Peng, Zheng Cui, Jun-Hong Shi, Zhijie Bagtzoglou, Amvrossios C. Univ Connecticut Dept Comp Sci & Engn Storrs CT 06269 USA Univ Connecticut Dept Civil & Environm Engn Storrs CT 06269 USA

Due to harsh aqueous environments, non-negligible node mobility and large network scale, localization for large-scale mobile underwater sensor networks is very challenging. In this paper, by utilizing the predictable mobility patterns of underwater objects, we propose a scheme, called Scalable Localization scheme with Mobility Prediction (SLMP), for underwater sensor networks. In SLMP, localization is performed in a hierarchical way, and the whole localization process is divided into two parts: anchor node localization and ordinary node localization. During the localization process, every node predicts its future mobility pattern according to its past known location information, and it can estimate its future location based on the predicted mobility pattern. Anchor nodes with known locations in the network will control the localization process in order to balance the trade-off between localization accuracy, localization coverage, and communication cost. We conduct extensive simulations, and our results show that SLMP can greatly reduce localization communication cost while maintaining relatively high localization coverage and localization accuracy.

关键词： network architecture and design network communications network protocols applications miscellaneous localization underwater sensor networks

来源：评论

学校读者我要写书评

暂无评论

Flexible Medical-Grade networks

引用

IT PROFESSIONAL 2011年第3期13卷 48-51页

作者： Teeter, James J., II Indiana State Univ Terre Haute IN 47809 USA

Healthcare organizations must test their network infrastructures for disaster recovery and emergency mode operations, yet most can't afford to operate the complicated protocols needed for safe testing. The Rapid A... 详细信息

关键词： Best practices Fault tolerance Hospitals Keywords: technology management Media Access Protocol Medical information systems Medical services Multiprotocol label switching network servers Radio access networks Rapid Adjustable network (RAN) complicated protocol disaster recovery emergency mode operation flexible medical-grade network health care healthcare organization information technology infrastructure protection internetworking medical computing network architecture and design network infrastructure rapid adjustable network architecture

来源：评论

学校读者我要写书评

暂无评论

Context-Based network Estimation for Energy-Efficient Ubiquitous Wireless Connectivity

引用

IEEE TRANSACTIONS ON MOBILE COMPUTING 2011年第1期10卷 54-66页

作者： Rahmati, Ahmad Zhong, Lin Rice Univ Dept Elect & Comp Engn Houston TX 77005 USA

Context information brings new opportunities for efficient and effective system resource management of mobile devices. In this work, we focus on the use of context information to achieve energy-efficient, ubiquitous wireless connectivity. Our field-collected data show that the energy cost of network interfaces poses a great challenge to ubiquitous connectivity, despite decent availability of cellular networks. We propose to leverage the complementary strengths of Wi-Fi and cellular interfaces by automatically selecting the most efficient one based on context information. We formulate the selection of wireless interfaces as a statistical decision problem. The challenge is to accurately estimate Wi-Fi network conditions without powering up the network interface. We explore the use of different context information, including time, history, cellular network conditions, and device motion, to statistically estimate Wi-Fi network conditions with negligible overhead. We evaluate several context-based algorithms for the estimation and prediction of current and future network conditions. Simulations using field-collected traces show that our network estimation algorithms can improve the average battery lifetime of a commercial mobile phone for an ECG reporting application by 40 percent, very close to the estimated theoretical upper bound of 42 percent. Furthermore, our most effective algorithm can predict Wi-Fi availability for one and ten hours into the future with 95 and 90 percent accuracy, respectively.

关键词： network architecture and design local and wide-area networks

来源：评论

学校读者我要写书评

暂无评论

Lattice QCD Applications on QPACE

Lattice QCD Applications on QPACE

引用

International Conference on Computational Science (ICCS) on the Ascent of Computational Excellence

作者： Nakamura, Y. Nobile, A. Pleiter, D. Simma, H. Streuer, T. Wettig, T. Winter, F. Univ Tsukuba Ctr Computat Sci Tsukuba Ibaraki 3058577 Japan Univ Regensburg Dept Phys D-93040 Regensburg Germany Deutsches Elekt Synchrotron DESY D-15738 Zeuthen Germany Univ Edinburgh Sch Phys Edinburgh EH9 3JZ Midlothian Scotland

QPACE is a novel massively parallel architecture optimized for lattice QCD simulations. A single QPACE node is based on the IBM PowerXCell 8i processor. The nodes are interconnected by a custom 3-dimensional torus network implemented on an FPGA. The compute power of the processor is provided by 8 Synergistic Processing Units. Making efficient use of these accelerator cores in scientific applications is challenging. In this paper we describe our strategies for porting applications to the QPACE architecture and report on performance numbers.

关键词： Parallel architectures network architecture and design computer applications

来源：评论

学校读者我要写书评

暂无评论

Lattice QCD Applications on QPACE

引用

Procedia Computer Science 2011年 4卷 841-851页

作者： Y. Nakamura A. Nobile D. Pleiter H. Simma T. Streuer T. Wettig F. Winter Center for Computational Sciences University of Tsukuba Ibaraki 305-8577 Japan Department of Physics University of Regensburg 93040 Regensburg Germany Deutsches Elektronen-Synchrotron DESY 15738 Zeuthen Germany School of Physics University of Edinburgh Edinburgh EH9 3JZ UK

QPACE is a novel massively parallel architecture optimized for lattice QCD simulations. A single QPACE node is based on the IBM PowerXCell 8i processor. The nodes are interconnected by a custom 3-dimensional torus network implemented on an FPGA. The compute power of the processor is provided by 8 Synergistic Processing Units. Making effcient use of these accelerator cores in scientific applications is challenging. In this paper we describe our strategies for porting applications to the QPACE architecture and report on performance numbers.

关键词： Parallel architectures network architecture and design computer applications 12.38.Gc

来源：评论

学校读者我要写书评

暂无评论

Buffer Management Strategies to Reduce HoL Blocking

引用

IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 2010年第6期21卷 739-753页

作者： Nachiondo, Teresa Flich, Jose Duato, Jose Univ Politecn Valencia Dept DISCA E-46071 Valencia Spain

Congestion management is likely to become a critical issue in interconnection networks, as increasing power consumption and cost concerns lead to improvements in the efficiency of network resources. In previous configurations, networks were usually oversized and underutilized. In a smaller network, however, contention is more likely to occur and blocked packets cause head-of-line (HoL) blocking among the rest of the packets, spreading congestion quickly. The best-known solution to HoL blocking is Virtual Output Queues (VOQs). However, the cost of implementing VOQs increases quadratically with the number of output ports in the network, making it unpractical. The situation is aggravated when several priorities and/or Quality of Service (QoS) levels must be supported. Therefore, a more scalable and cost-effective solution is required to reduce or eliminate HoL blocking. In this paper, we present a family of methodologies, referred to as Destination-Based Buffer Management (DBBM), to reduce/eliminate the HoL blocking effect on interconnection networks. DBBM efficiently uses the resources (mainly memory queues) of the network. These methodologies are comprehensively evaluated in terms of throughput, scalability, and fairness. Results show that using the DBBM strategy, with a reduced number of queues at each switch, it is possible to achieve roughly the same throughput as the VOQ mechanism. Moreover, all of the proposed strategies are designed in such a way that they can be used in any switch architecture. We compare DBBM with RECN, a sophisticated mechanism that eliminates HoL blocking in congestion situations. Our mechanism is able to achieve almost the same performance with very low logic requirements (in contrast with RECN).

关键词： Communication/networking and information technology network architecture and design network operating systems distributed systems computer systems organization

来源：评论

学校读者我要写书评

暂无评论

Sharing RFID and complex event data among organizations

引用

INFORMATION SYSTEMS FRONTIERS 2010年第5期12卷 541-549页

作者： Ziekow, Holger Guenther, Oliver Humboldt Univ Inst Informat Syst D-10178 Berlin Germany

Integrating RFID data from various sources in a value chain is an important requirement for leveraging the full potential of the technology. To facilitate this crucial integration, the global standardization organization GS1 is currently developing a range of service specifications. Yet, the services specified so far do not enable event-based interaction schemes and do not leverage the detection of distributed complex events. In this paper we propose to fill this gap by means of a peer-to-peer based broker network that can realize event-based interaction on top of existing specifications. For this infrastructure we present a new method to improve in-network processing. As shown by our experiments, our method significantly reduces overall system load by exploiting a priori knowledge about the observed processes.

关键词： network architecture and design Administrative data processing Data sharing

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：