检索结果-内蒙古大学图书馆

Headlight prefetching and dynamic chaining for cooperative media streaming in mobile environments

IEEE Transactions on Mobile Computing 2009年第2期8卷 173-187页

作者： Wu, Shiow-Yang Hsu, Jungchu Chen, Chieh-Ming Department of Computer Science and Information Engineering National Dong Hwa University Hualien 974 Taiwan RandD Division i Software RandD Department III E-TEN Information Systems Co. Ltd. No. 256 Yangguang Street Neihu ChiuTaipei 114 Taiwan Microelectronics Technology Inc. No. 1 Innovation Road II Hsinchu Science Park Hsinchu 300 Taiwan

Media streaming in mobile environments is becoming more and more important with the proliferation of 3G technologies and the popularity of online media services such as news clips, live sports, and hot movies. To avoid disconnection and/or service breakdown when the users keep moving, proper data management strategies must be taken by all parties. We propose a two-level framework and a set of new techniques for cooperative media streaming in mobile environments. Headlight prefetching is designed for the cooperation of streaming access points to deal with the uncertainty of client movement and the requirement of seamless service handoff. For each mobile user, we maintain a virtual fan-shaped prefetching zone along the direction of movement similar to the headlight of a moving vehicle. The overlapping area and the accumulated virtual illuminance of the headlight zone on a particular cell determine the degree and volume of prefetching on that cell. Dynamic chaining is for the cooperation among mobile users to maximize cache utilization and streaming benefit. On receiving a media segment request from a mobile client, the streaming access point starts a search for possible supplying partners before attempting to a remote media server. If a qualified partner is found, the requesting client is chained to the partner and receives subsequent segments from the partner directly without server intervention. The client can itself be a supplying partner for other clients and naturally form a chain of users that are viewing and sharing the same media. Simulation results demonstrate that the integration of headlight prefetching and dynamic chaining can significantly decrease streaming disruptions, reduce bandwidth consumption, increase cache utilization, and improve service response time. © 2009 IEEE.

关键词： Information management

来源：评论

学校读者我要写书评

暂无评论

Optimal performance for detection systems in wireless passive sensor networks

Optimal performance for detection systems in wireless passiv...

引用

Mediterranean Conference on Control and Automation (MED)

作者： Ashraf Tantawy Xenofon Koutsoukos Gautam Biswas Institute for Software Integrated Systems (ISIS) Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN USA

Passive wireless sensors have emerged as a new technology to measure a vast majority of phenomena in our daily life. Passive sensors require no power source, and therefore their application domains are numerous, including health care, infrastructure protection, and national security, among many others. The deployment of wireless passive sensors and their readers has changed how detection needs to be performed. Passive sensors cannot pre-process the measurements as they have limited computational power. Therefore, no local decision is taken. Also, the reader polls the information from multiple sensors at the same time, and this causes collisions and hence packet drops and delays. In this paper, we formulate the detection performance, with non-ideal channels, in a probabilistic way, and compare with classical detection performance. We design an optimal adaptive Neyman-Pearson detector, given the channel probabilistic model, by formulating and solving a constrained optimization problem.

关键词： Wireless sensor networks Sensor systems Sensor phenomena and characterization Communication system security Medical services Power system protection National security Power measurement Delay effects Detectors

来源：评论

学校读者我要写书评

暂无评论

Design Pattern for Self-Organizing Emergent systems Based on Digital Infochemicals

Design Pattern for Self-Organizing Emergent Systems Based on...

引用

IEEE Workshop on engineering of Autonomic and Autonomous systems (EASE)

作者： Holger Kasinger Bernhard Bauer Jörg Denzinger Institute of Software and Systems Engineering University of Augsburg Augsburg Germany Department of Computer Science University of Calgary Calgary Canada

An essential element in the engineering of computer systems are design patterns that capture current best practice and knowledge about recurring solutions for standard problems. In case of decentralized autonomic computing systems, also known as self-organizing emergent systems, appropriate design patterns have to structurally describe decentralized coordination mechanisms along with information on which kind of macroscopic effects, the self-* properties, can be achieved in which situations. In this paper we present a design pattern for self-organizing emergent systems coordinating by means of digital infochemicals. Infochemicals, in the natural context, are chemical substances that convey information in the interaction between two individuals. Because infochemical coordination is the most universally employed mechanism of communication in nature, there exists plenty of inspiring examples of decentralized coordination usable for the solution of complex problems in need of certain self-properties. The presented design pattern captures the general biological principles behind infochemical coordination, which simplifies a systematical systems engineering. It extends existing coordination models, in particular pheromone-based coordination and digital semiochemical coordination, in terms of terminology, functionality, as well as generality, and thus becomes applicable to a much wider set of problem domains.

关键词： Design engineering systems engineering and theory Knowledge engineering Chemicals Organisms Best practices Mechanical factors Context Terminology Biology computing

来源：评论

学校读者我要写书评

暂无评论

Detection Using Intermittent Observations for Passive Wireless Sensors

Detection Using Intermittent Observations for Passive Wirele...

引用

2009 American Control Conference (ACC 2009)

作者： Ashraf Tantawy Xenofon Koutsoukos Gautam Biswas Institute for Software Integrated Systems and the Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN 37235 USA

ISBN: (纸本)9781424445233

Passive wireless sensors have emerged as a new technology to measure multiple phenomena in our daily life. Passive sensors require no power source, and therefore their application domains are numerous, including health care, infrastructure protection, and national security. The deployment of passive wireless sensors and their readers has changed how detection needs to be performed. Passive sensors cannot preprocess the measurements as they have limited computational power. Therefore, no local decision is taken. Also, the reader polls the information from multiple sensors at the same time, and this causes collisions and hence packet drops and delays. Detectors designed without considering the properties of the communication channel have degraded performance. Therefore, analysis is required to quantify the degradation and take the necessary remedy action. In this paper, we study the effect of sensor-reader channel imperfection on the local detection performance of the reader, assuming no data pre-processing at the passive sensor. We consider the case of a single sensor-reader communication over a Bernoulli communication channel. We formulate the detector performance and compare with the ideal case. We present the problem of DC level detection in White Gaussian Noise, as a case study. Finally, we propose a heuristic approach to restore the original detector performance working with non-ideal channel, with the cost of increasing the delay for detection.

关键词： Wireless sensor networks Sensor phenomena and characterization Communication system security Detectors Delay Communication channels Degradation Medical services Protection National security

来源：评论

学校读者我要写书评

暂无评论

Gigabit Ethernet based substation under IEC61850 standard

Gigabit Ethernet based substation under IEC61850 standard

引用

International Conference on computer, Control and Communication

作者： Ali Raza Khalil Ullah Saleem Ahmed Salman Ahmed Hyuk-Soo Jang Hyo-Sik Yang Department of Computer Software Myongji University Yongin Korea Department of Electronics and Communication Engineering Myongji University Yongin Korea Department of Computer Systems Engineering Mehran University Jamshoro Pakistan Department of Computer Engineering Sejong University Seoul South Korea

ISBN: (纸本)9781424433131

Communication architecture for substation automation is one of the challenging and subtle tasks to address in order to visualize the substation into digital world under the umbrella of IEC61850. Communication paradigm for substation automation demands critical importance because of two reasons; as communication arena is changing day by day so it is convenient to opt for something that is simple to deploy and incur a less cost in terms of time and asset when migration is to be considered since data-intensive applications drive the incremental demand for bandwidth as per growing need with the expansion of concerned network and last but not least the interoperability as it is one of the core constrained put by IEC61850 for substation automation. So it is viable to consider Ethernet as the most promising solution for the communication architecture of substation automation as Ethernet technology has changed the trend of communication network because of its availability, efficiency, and cost effectiveness on the other hand interoperability is assured based on the proven and highly deployed industrial Ethernet. This paper presents analysis and the crucial need for the deployment of Gigabit Ethernet in the substation and also presents how Ethernet technology can help in the substation automation as a long run solution in the changing arena of communication as Ethernet is one of the most pervasive communication technologies. In the end we have performed simulations in NS-2 to prove that our suggested communication paradigm is optimal in various regards by keeping into consideration the constraints imposed by IEC61850.

关键词： Ethernet networks Substation automation Communications technology Costs Access protocols Object oriented modeling Standards development Delay Standardization Availability

来源：评论

学校读者我要写书评

暂无评论

Baseline efficiency in EPON based architecture to inter-network substations

Baseline efficiency in EPON based architecture to inter-netw...

引用

International Conference on computer, Control and Communication

ISBN: (纸本)9781424433131

The design of cost-effective, interoperable, and efficient communication architecture is indeed one of the pressing needs not only for the realization of substation automation (SA) as per specification of IEC61850 but also to inter-connect different substations with minimum cost to bring data from all substations on the single information highway thereby paving a smooth way to centralize all the available information. Ethernet technology has dramatically changed the communication trend because of its availability, efficiency, cost effectiveness, proven interoperability, and capability to drive on-demand bandwidth as per incremental growth and expansion of the network and on the other hand optical fiber communication system is one of the technically attractive communication medium due to its high capacity, efficiency, and security. Therefore, EPON (Ethernet Passive Optical Network) is the desired communication paradigm for the SA as it is shipped with the two most demanding communication trends, i.e., Ethernet and Fiber Optics in a single package. EPON underscores the importance of not only last-mile operability for inter-connecting different substations but can also play a vital role when ATM is replaced with GPON (Gigabit Passive Optical Network) for the long-haul communication thereby saving the cost of protocol conversion. In this paper we propose EPON as the desired communication architecture for inter-connecting substations and present analysis related to the significant importance of EPON with respect to the deployment in the substation environment both internally and externally. Finally we show the result of simulations to validate the deployment and effectiveness of our purposed communication paradigm for substation.

关键词： EPON Costs Ethernet networks Pressing Substation automation Automated highways Availability Bandwidth Optical fiber communication Communication system security

来源：评论

学校读者我要写书评

暂无评论

The Optimal Searcher Path Problem with a Visibility Criterion in Discrete Time and Space

The Optimal Searcher Path Problem with a Visibility Criterio...

引用

International Conference on Information Fusion

作者： Michael Morin Irene Abi-Zeid Pascal Lang Luc Lamontagne Patrick Maupin Department of Computer Science and Software Engineering Universite Laval Department of Operations and Decision Systems Universite Laval Defence Research and Development Canada

ISBN: (纸本)9780982443804

In this paper, the problem of path planning for a ground search unit looking for an object of unknown location is considered. As in the classical optimal searcher path problem, the probability of finding the search object is the main criterion of optimality and the search unit is constrained by the environment topology that influences its choices for a navigable path as well as its detection capabilities. This paper proposes an extension to the classical optimal searcher path problem in discrete time and space by integrating inter-region visibility as an additional criterion. This new formulation allows a refinement in the discretization of the space in which a ground search unit evolves. A general mixed-integer programming model is proposed, and experimental results with a moving object in grid environments are discussed.

关键词： Optimal searcher path problem Visibility Path planning Search theory Mixed integer programming

来源：评论

学校读者我要写书评

暂无评论

Newborn screening system based on adaptive feature selection and support vector machines

Newborn screening system based on adaptive feature selection...

引用

2009 9th IEEE International Conference on Bioinformatics and Bioengineering, BIBE 2009

作者： Hsieh, Sung-Huai Chien, Yin-Hsiu Shen, Chia-Ping Chen, Wei-Hsin Chen, Po-Hao Hsieh, Sheau-Ling Cheng, Po-Hsun Lai, Feipei Information Systems Office National Taiwan University Hospital Taipei Taiwan Department of Computer Science and Information Engineering National Taiwan University Taiwan Department of Electrical Engineering National Taiwan University Taipei Taiwan Network and Computer Centre National Chiao Tung University Hsin Chu Taiwan Graduate Institute of Biomedical Electronics and Bioinformatics National Taiwan University Taiwan Department of Software Engineering National Kaohsiung Normal University Taiwan Department of Medical Genetics National Taiwan University Hospital Taiwan

ISBN: (纸本)9780769536569

The clinical symptoms of metabolic disorders during neonatal period are often not apparent, if not treated early irreversible damages such as mental retardation may occur, even death. Therefore, practicing newborn screening is very important to prevent neonatal from these damages. In this paper, the newborn screening system used support vector machines (SVM) classification technique is proposed in place of cut-off value decision to evaluate the metabolic substances concentration raw data obtained from tandem mass spectrometry (MS/MS) and determine whether the newborn has some kinds of metabolic disorder diseases. On the basis of the proposed features, new analytic combinations are identified with superior discriminatory performance compared with the best published combinations. Classifiers built with the feature selection to find C3/C2, C3 and C16 of three key point features achieved diagnostic sensitivities, specificities and accuracy approaching 100%. © 2009 IEEE.

关键词： Support vector machines

来源：评论

学校读者我要写书评

暂无评论

Three-layer architecture model (TLAM) for energy conservation in wireless sensor networks

Three-layer architecture model (TLAM) for energy conservatio...

引用

International Conference on Ultra Modern Telecommunications and Workshops (ICUMT)

作者： Sugam Sharma Mamta Rani Department of Computer Science Iowa State University Ames IA USA Faculty of Computer Systems & Software Engineering Universiti Malaysia Pahang Kuantan Malaysia

We propose a three-layer architecture model (TLAM) for wireless sensor networks. The first layer (bottom layer) consists of a network of resource-constrained sensor nodes deployed in the field. The second layer contains a set of resource-rich dynamic sink nodes forming an ad hoc network. The sinks at layer second are responsible to monitor and collect data from a region, called cluster. So the sinks at second layer are also knows as cluster sinks. At the third layer, there is a resource-rich static sink, known as zonal sink also, responsible for data collection from cluster sinks. A cluster sink may be few hops away from a static sensor node and moves to the vicinity of sensor nodes to collect the data. Each cluster sink continuously updates the zonal sink by propagating the collected data from the respective cluster. The zonal sink buffers the collected data and propagates to base station. Zonal sink is the one, responsible for data transmission from network environment to the base station, where the data is processed for further use. TLAM approach is robust, increases sensor life by allowing them to operate with a limited transmission range only and provides reduced delay as cluster sink continuously updates to zonal sink without query.

关键词： Energy conservation Wireless sensor networks Peer to peer computing Intelligent sensors Monitoring Base stations computer architecture Robustness Sensor systems Batteries

来源：评论

学校读者我要写书评

暂无评论

Exploration of Slot Allocation for On-Chip TDM Virtual Circuits

Exploration of Slot Allocation for On-Chip TDM Virtual Circu...

引用

Euromicro Symposium on Digital System Design

作者： Li Tong Zhonghai Lu Hua Zhang School of Computer and Communication Engineering Tianjin University of Technology Tianjin China Department of Electronic Computer and Software Systems Royal Institute of Technology Stockholm Sweden

Time-Division-Multiplexing (TDM) Virtual Circuit (VC) has been proposed to guarantee the Quality-of-Service requirements in communication for Network-on-Chip. In this paper, we explore the design space of slot allocation for configuring TDM VCs. Specifically, we investigate different slot assignment schemes, namely, distributed, random and consecutive schemes, which have significant impact on the configurability. We also propose to construct disjoint connected VC sets to effectively reduce the search space. We have realized and integrated them into our VC configuration flow. Our experimental results suggest that the optimal slot allocation cycle equals to the ratio of the link bandwidth to the maximal VC bandwidth, and the distributed slot assignment scheme performs better than the random and consecutive schemes.

关键词： Time division multiplexing Circuits Virtual colonoscopy Switches Network-on-a-chip Bandwidth Routing computer networks System-on-a-chip Packet switching

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：