检索结果-内蒙古大学图书馆

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： Xiang Ji Hongyuan Zha The Pennsylvania State University University Park PA

ISBN: (纸本)9781581137071

Recently, a family of methods have been proposed for large scale ad hoc sensor networks that estimate the approximate positions of sensor nodes in the network. In the paper, we first investigate some situations that most existing sensor positioning methods fail to perform well. An example of such situations is that the topology of a sensor network is anisotropic. Then, we study the multidimensional scaling (MDS) technique, and a centralized sensor positioning algorithm is proposed based on MDS. We also propose a distributed sensor positioning algorithm, which is in iteration paradigm, to address these situations. The MDS technique is applied to recover a series of local maps for adjacent sensors, and these maps are then stitched together to form a portion of globe map. At last, the estimated anchor positions are compared with the anchors' physical position for accurate positioning.

关键词： position estimation multidimensional scaling ad-hoc sensor network

来源：评论

学校读者我要写书评

暂无评论

DFuse: a framework for distributed data fusion 03

DFuse: a framework for distributed data fusion

引用

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： Rajnish Kumar Matthew Wolenetz Bikash Agarwalla JunSuk Shin Phillip Hutto Arnab Paul Umakishore Ramachandran Georgia Institute of Technology

ISBN: (纸本)9781581137071

Simple in-network data aggregation (or fusion) techniques for sensor networks have been the focus of several recent research efforts, but they are insufficient to support advanced fusion applications. We extend these techniques to future sensor networks and ask two related questions: (a) what is the appropriate set of data fusion techniques, and (b) how do we dynamically assign aggregation roles to the nodes of a sensor network. We have developed an architectural framework, DFuse, for answering these two questions. It consists of a data fusion API and a distributed algorithm for energy-aware role assignment. The fusion API enables an application to be specified as a coarse-grained dataflow graph, and eases application development and deployment. The role assignment algorithm maps the graph onto the network, and optimally adapts the mapping at run-time using role migration. Experiments on an iPAQ farm show that, the fusion API has low-overhead, and the role assignment algorithm with role migration significantly increases the network lifetime compared to any static assignment.

关键词： role assignment in-network aggregation energy awareness platform sensor network middleware data fusion

来源：评论

学校读者我要写书评

暂无评论

Development of a standard robotic dummy for the purpose of evaluating rescue equipment and skill

Development of a standard robotic dummy for the purpose of e...

引用

Proceedings 2003 ieee/RSJ international conference on Intelligent Robots and systems (IROS 2003) (Cat. No.03CH37453)

作者： Y. Masutani K. Osuka M. Kurisu T. Doi T. Kaneda Xin-Zhi Zheng H. Sugimoto T. Azuma Graduate School of Engineering Science Osaka University Toyonaka Osaka Japan Kyoto University Japan Tokyo Denki University Japan Osaka College of Tech Japan ASTEM/RI Kyoto Kyoto Kagaku Company Limited Japan Nitta Corporation

Concepts and necessity of a dummy (human model) which can simulate a disaster victim for the purpose of evaluating rescue equipments including robots and rescue skills of human and robots are proposed. By contrast of conventional dummies in various fields, the concrete requirements are made clear. The plan of research and development project based on the concept is described. In the latter part of this paper, the 1st prototype under development is introduced. It is based on a human model (doll) for training of bathing assistance, and is equipped with 8-channel telemetric sensors, a wireless camera, a voice recorder, a heater vest, and a carbon dioxide gas tank.

关键词： standards development Robots Humans Concrete Research and development Prototypes Telemetry Gas detectors Thermal sensors Wireless sensor networks

来源：评论

学校读者我要写书评

暂无评论

Multi-dimensional range queries in sensor networks 03

Multi-dimensional range queries in sensor networks

引用

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： Xin Li Young Jin Kim Ramesh Govindan Wei Hong University of Southern California Intel Research Lab at Berkeley

ISBN: (纸本)9781581137071

In many sensor networks, data or events are named by attributes. Many of these attributes have scalar values, so one natural way to query events of interest is to use a multi-dimensional range query. An example is: "List all events whose temperature lies between 50° and 60°, and whose light levels lie between 10 and 15." Such queries are useful for correlating events occurring within the *** this paper, we describe the design of a distributed index that scalably supports multi-dimensional range queries. Our distributed index for multi-dimensional data (or DIM) uses a novel geographic embedding of a classical index data structure, and is built upon the GPSR geographic routing algorithm. Our analysis reveals that, under reasonable assumptions about query distributions, DIMs scale quite well with network size (both insertion and query costs scale as O(√N)). In detailed simulations, we show that in practice, the insertion and query costs of other alternatives are sometimes an order of magnitude more than the costs of DIMs, even for moderately sized network. Finally, experiments on a small scale testbed validate the feasibility of DIMs.

关键词： DIM multi-dimensional range queries

来源：评论

学校读者我要写书评

暂无评论

Timing-sync protocol for sensor networks 03

Timing-sync protocol for sensor networks

引用

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： Saurabh Ganeriwal Ram Kumar Mani B. Srivastava University of California Los Angeles Los Angeles CA

ISBN: (纸本)9781581137071

Wireless ad-hoc sensor networks have emerged as an interesting and important research area in the last few years. The applications envisioned for such networks require collaborative execution of a distributed task amongst a large set of sensor nodes. This is realized by exchanging messages that are time-stamped using the local clocks on the nodes. Therefore, time synchronization becomes an indispensable piece of infrastructure in such systems. For years, protocols such as NTP have kept the clocks of networked systems in perfect synchrony. However, this new class of networks has a large density of nodes and very limited energy resource at every node; this leads to scalability requirements while limiting the resources that can be used to achieve them. A new approach to time synchronization is needed for sensor *** this paper, we present Timing-sync Protocol for sensor Networks (TPSN) that aims at providing network-wide time synchronization in a sensor network. The algorithm works in two steps. In the first step, a hierarchical structure is established in the network and then a pair wise synchronization is performed along the edges of this structure to establish a global timescale throughout the network. Eventually all nodes in the network synchronize their clocks to a reference node. We implement our algorithm on Berkeley motes and show that it can synchronize a pair of neighboring motes to an average accuracy of less than 20ms. We argue that TPSN roughly gives a 2x better performance as compared to Reference Broadcast Synchronization (RBS) and verify this by implementing RBS on motes. We also show the performance of TPSN over small multihop networks of motes and use simulations to verify its accuracy over large-scale networks. We show that the synchronization accuracy does not degrade significantly with the increase in number of nodes being deployed, making TPSN completely scalable.

关键词： sensor networks medium access control time synchronization clock drift packet delay

来源：评论

学校读者我要写书评

暂无评论

Practical lazy scheduling in sensor networks 03

Practical lazy scheduling in sensor networks

引用

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： Ramana Rao Kompella Alex C. Snoeren University of California San Diego CA

ISBN: (纸本)9781581137071

Experience has shown that the power consumption of sensors and other wireless computational devices is often dominated by their communication patterns. We present a practical realization of lazy packet scheduling that attempts to minimize the total transmission energy in a broadcast network by dynamically adjusting each node's transmission power and rate on a per-packet basis. Lazy packet scheduling leverages the fact that many channel coding schemes are more efficient at lower transmission rates; that is, the energy required to send a fixed amount of data can be reduced by transmitting the data at a lower bit rate and transmission *** optimal per-packet transmission rate in a multi-node network is governed in practice by the available bit rates of the given transceiver(s), the nodes' delay tolerance, and the offered load at every node contending for the shared broadcast channel. We propose an extension to the traditional CSMACA MAC scheme called L-CSMACA that allows individual nodes to continually estimate the current demand for a broadcast channel and adjust their transmission schedules accordingly. Our simulation results show that L-CSMACA can provide improved energy efficiency in a single-hop, broadcast network (20--25% with more than 10 nodes, and up to 99% for four nodes with a standard power function) for both Poisson and bursty arrivals with only minor degradation the capacity of the channe.

关键词： distributed algorithms lazy scheduling energy conservation sensor networks

来源：评论

学校读者我要写书评

暂无评论

GEM: Graph EMbedding for routing and data-centric storage in sensor networks without geographic information 03

GEM: Graph EMbedding for routing and data-centric storage in...

引用

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： James Newsome Dawn Song Carnegie Mellon University

ISBN: (纸本)9781581137071

The widespread deployment of sensor networks is on the horizon. One of the main challenges in sensor networks is to process and aggregate data in the network rather than wasting energy by sending large amounts of raw data to reply to a query. Some efficient data dissemination methods, particularly data-centric storage and information aggregation, rely on efficient routing from one node to another. In this paper we introduce GEM (Graph EMbedding for sensor networks), an infrastructure for node-to-node routing and data-centric storage and information processing in sensor networks. Unlike previous approaches, it does not depend on geographic information, and it works well even in the face of physical obstacles. In GEM, we construct a labeled graph that can be embedded in the original network topology in an efficient and distributed fashion. In that graph, each node is given a label that encodes its position in the original network topology. This allows messages to be efficiently routed through the network, while each node only needs to know the labels of its *** demonstrate how GEM can be applied, we have developed a concrete graph embedding method, VPCS (Virtual Polar Coordinate Space). In VPCS, we embed a ringed tree into the network topology, and label the nodes in such a manner as to create a virtual polar coordinate space. We have also developed VPCR, an efficient routing algorithm that uses VPCS. VPCR is the first algorithm for node-to-node routing that guarantees reachability, requires each node to keep state only about its immediate neighbors, and requires no geographic information. Our simulation results show that VPCR is robust on dynamic networks, works well in the face of voids and obstacles, and scales well with network size and density.

关键词： data-centric storage routing sensor networks

来源：评论

学校读者我要写书评

暂无评论

Poster abstract: spatial average of a continuous physical process in sensor networks 03

Poster abstract: spatial average of a continuous physical pr...

引用

Proceedings of the 1st international conference on Embedded networked sensor systems

作者： Saurabh Ganeriwal Chih Chieh Han Mani B. Srivastava University of California Los Angeles Los Angeles CA

ISBN: (纸本)9781581137071

Wireless ad-hoc sensor networks have caught the fancy of many researchers through the world in a very small span of time. Although notable progress has been made in several key areas, several researchers falter in the way they look at sensor networks i.e. just another kind of wireless ad hoc networks, albeit one composed of energy constrained nodes. A key aspect that makes sensor networks different from traditional networks is their strong link to the physical world. We develop this perspective by studying an interesting class of sensor network applications called aggregation *** argue that when a user queries for aggregates like maximum, average etc., he is interested in knowing the statistics of the underlying physical process. In general, this is not equivalent to the statistics gathered from a bunch of nodes. We introduce a distinction between aggregates calculated over a region and aggregates calculated over a discrete set of nodes. We classify them as spatial and nodal aggregates respectively. Till now, researchers have followed the approach of doing nodal aggregation in response to every user query in sensor networks. For a continuous physical process and a random deployment of sensor nodes, which are a norm for sensor networks, the conventional approach of doing nodal aggregation produces inaccurate *** verify our claim by studying a specific aggregation function namely the average over a region (spatial average) in detail. We use a voronoi-based approach to propose an algorithm for calculating spatial average in sensor networks. The algorithm can work in two modes -- centralized and distributed. The energy and accuracy tradeoff associated with each of the two modes is analyzed in detail. The efficacy of the proposed algorithm is tested over a wide variety of physical processes including real precipitation data of South America acquired over a span of past 50 years. We will show that our algorithm gives a 2-8 times performance gain as comp

关键词： voronoi average sensor networks aggregation

来源：评论

学校读者我要写书评

暂无评论

Performance of a distributed robotic system using shared communications channels

引用

ieee TRANSACTIONS ON ROBOTICS AND AUTOMATION 2002年第5期18卷 713-727页

作者： Rybski, PE stoeter, SA Gini, M Hougen, DF Papanikolopoulos, NP Univ Minnesota Dept Comp Sci & Engn Ctr Distributed Robot Minneapolis MN 55455 USA

We have designed and built a set of miniature robots called Scouts and have developed a distributed software system to control them. This paper addresses the fundamental choices we made in the design of the control software, describes experimental results in a surveillance task, and analyzes the factors that affect robot performance. Space and power limitations on the Scouts severely restrict the computational power of their on-board computers, requiring a proxy-processing scheme in which the robots depend on remote computers for their computing needs. While this allows the robots to be autonomous, the fact that robots' behaviors are executed remotely introduces an additional complication-sensor data and motion commands have to be exchanged using wireless communications channels. Communications channels cannot always be shared, thus requiring the robots to obtain exclusive access to them. We present experimental results on a surveillance task in which multiple robots patrol an area and watch for motion. We discuss how the limited communications bandwidth affects robot performance in accomplishing the task, and analyze how performance depends on the number of robots that share the bandwidth.

关键词： distributed software architecture mobile robots multiple robots resource allocation

来源：评论

学校读者我要写书评

暂无评论

Design of a broadband microwave amplifier constructed with mixed lumped and distributed elements for mobile communication 1

Design of a broadband microwave amplifier constructed with m...

引用

1st ieee international conference on Circuits and systems for Communications

作者： Yarman, BS Çimen, EG Isik Univ TR-80670 Istanbul Turkey

ISBN: (纸本)5742202601

In this paper, we designed a broadband microwave amplifier utilizing. the "semi-analytic method to describe symmetrical lossless two-ports with two-kinds of elements", namely, distributed and lumped elements in cascade connection. It is expected that the results presented in this paper will find immediate application to design analog/digital mobile communication systems put on MMICs or VLSI chips.

关键词： amplifier design lossless two-ports matching networks

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：