检索结果-内蒙古大学图书馆

Empirical evaluation of querying mechanisms for unstructured wireless sensor networks

computer Communication Review 2008年第3期38卷 17-26页

作者： Ahn, Joon Kapadia, Shyam Pattem, Sundeep Sridharan, Avinash Zuniga, Marco Jun, Jung-Hyun Avin, Chen Krishnamachari, Bhaskar Dept. of Electrical Engineering University of Southern California Los AngelesCA United States Cisco Systems Inc. San JoseCA United States Digital Enterprise Research Institute National University of Ireland Galway Ireland Dept. of Electrical and Computer Engineering University of Cincinnati CincinnatiOH United States Communication Systems Engineering Dept. Ben Gurion University of the Negev Israel

In the last few years, several studies have analyzed the performance of flooding and random walks as querying mechanisms for unstructured wireless sensor networks. However, most of the work is theoretical in nature and while providing insights into the asymptotic behavior of these querying mechanisms, does not account for the non-idealities faced by the network in real deployments. In this paper, we propose a 3-way handshake protocol as a reliable implementation of a random walk and compare its performance with flooding in real environments. The metrics considered are delay, reliability and transmission cost. Our initial results suggest that flooding is better suited for low-interference environments, while random walks might be a better option in networks with high interference. We also present possible research directions to improve the performance oflooding and random walks. © 2008 Authors.

关键词： Structured Query Language

来源：评论

学校读者我要写书评

暂无评论

Neuro-fuzzy control of a biped robot able to be subjected to an external pushing force in the sagittal plane

Neuro-fuzzy control of a biped robot able to be subjected to...

引用

2008 IEEE/RSJ International Conference on Intelligent Robots and systems, IROS

作者： Ferreira, João P. Crisóstomo, Manuel Coimbra, A. Paulo Institute of Systems and Robotics Dept. of Electrical and Computer Engineering Univ. of Coimbra Portugal Dept. of Electrical Engineering Superior Institute of Engineering of Coimbra Coimbra Portugal

ISBN: (纸本)9781424420582

This paper describes the control of an autonomous biped robot capable to be subjected to external pushing forces applied in the sagittal plane. A 1st order Takagi-Sugeno-Kang (TSK) type neuro fuzzy net, that was trained based on experimental and simulation data, is used. This net uses the zero moment point (ZMP) position and its variation as inputs, and the sagittal correction of the robot's body is obtained as the output. The ZMP is obtained be acquiring use of the force distribution on four force sensors placed under each robot's foot. The gait implemented on our biped is similar to a human gait. A human gait was acquired and adapted to the robot size. Some experiments were carried out and the results show that the used gait combined with the TSK neuro fuzzy net is appropriate to be used in the control of a biped robot, with and without an applied external force.

关键词： Robots

来源：评论

学校读者我要写书评

暂无评论

The servomechanism problem for SISO positive LTI systems

Lecture Notes in Control and Information Sciences

引用

Lecture Notes in Control and Information Sciences 2008年 371卷 181-193页

作者： Roszak, Bartek Davison, Edward Systems Control Group Dept. of Electrical and Computer Engineering University of Toronto Toronto Ont. M5S 1A4 Canada

ISBN: (纸本)9781848001541

In this paper, we study the servomechanism problem for positive LTI systems. In particular, we consider the robust servomechanism problem of nonnegative constant reference signals for stable SISO positive LTI systems with constant disturbances, for the case when the plant model of the system is not known. A positive LTI system is an LTI system with the imposed constraint that the state, output and/or input variables be nonnegative for all time. This type of constraint is quite natural to apply, since the property of nonnegativity occurs quite frequently in practical applications and in nature, e.g. in pharmacodynamic applications, infusion of vasoactive drugs, chemical systems. A special class of positive systems that is of significant importance and appears quite frequently in the literature is the class of compartmental systems;these systems are composed of a finite number of storage devices or reservoirs and model various gas, fluid, and solid exchange networks. Positive systems have been of great interest to numerous researchers over several decades. Interesting results obtained on positive systems span the topics of reachability and controllability, realization theory for positive systems, stability control, and control via pole-assignment. However, to date, there appears that no study has been carried out on the servomechanism problem for positive LTI systems;thus we focus our attention on this topic in the paper. Various applications of the results are applied to a number of positive system problems obtained from the literature. © 2008 Springer London.

关键词： Linear systems

来源：评论

学校读者我要写书评

暂无评论

Exact Dynamic Programming for decentralized POMDPs with lossless policy compression

Exact Dynamic Programming for decentralized POMDPs with loss...

引用

18th International Conference on Automated Planning and Scheduling, ICAPS 2008

作者： Boularias, Abdeslam Chaib-Draa, Brahim Computer Science and Software Engineering Dept. Laval University QC Glk 7p4 Canada

ISBN: (纸本)9781577353867

High dimensionality of belief space in DEC-POMDPs is one of the major causes that makes the optimal joint policy computation intractable. The belief state for a given agent is a probability distribution over the system states and the policies of other agents. Belief compression is an efficient POMDP approach that speeds up planning algorithms by projecting the belief state space to a low-dimensional one. In this paper, we introduce a new method for solving DEC-POMDP problems, based on the compression of the policy belief space. The reduced policy space contains sequences of actions and observations that are linearly independent. We tested our approach on two benchmark problems, and the preliminary results confirm that Dynamic Programming algorithm scales up better when the policy belief is compressed. Copyright © 2008, Association for the Advancement of Artificial Intelligence (***). All rights reserved.

关键词： Probability distributions

来源：评论

学校读者我要写书评

暂无评论

A cloaking algorithm based on spatial networks for location privacy

A cloaking algorithm based on spatial networks for location ...

引用

2008 IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing, SUTC 2008

作者： Li, Po-Yi Peng, Wen-Chih Wang, Tsung-Wei Ku, Wei-Shinn Xu, Jianliang Hamilton Jr., J.A. Dept. of Computer Science National Chiao Tung University Taiwan Dept. of Computer Science and Software Engineering Auburn University Auburn United States Dept. of Computer Science Hong Kong Baptist University Hong Kong Hong Kong

ISBN: (纸本)9780769531588

Most of research efforts have elaborated on k-anonymity for location privacy. The general architecture for implementing k-anonymity is that there is one trusted server (referred to as location anonymizer) responsible for cloaking at least k users' locations for protecting location privacy. A location anonymizer will generate cloaked regions in which there are at least k users for query processing. Prior works only explore grid shape cloaked regions. However, grid shape cloaked regions result in a considerable amount of query results, thereby increasing the overhead of filtering unwanted query results. In this paper, we propose a cloaking algorithm in which cloaked regions are generated according to the features of spatial networks. By exploring the features of spatial networks, the cloaked regions are very efficient for reducing query results and improving cache utilization of mobile devices. Furthermore, an index structure for spatial networks is built and in light of the proposed index structure, we develop a Spatial-Temporal Connective Cloaking algorithm(abbreviated as STCC). A simulator is implemented and extensive experiments are conducted. Experimental results show that our proposed algorithm outperforms prior cloaking algorithms in terms of the candidate query results and the cache utilization. © 2008 IEEE.

关键词： Location

来源：评论

学校读者我要写书评

暂无评论

Towards automatic derivation of a product performance model from a UML software product line model

Towards automatic derivation of a product performance model ...

引用

7th International Workshop on software and Performance 2008, WOSP'08

作者： Tawhid, Rasha Petriu, Dorina C. School of Computer Science Carleton University Ottawa ON Canada Dept. of Systems and Computer Engineering Carleton University Ottawa ON Canada

ISBN: (纸本)9781595938732

software Product Line (SPL) engineering is a software development approach that takes advantage of the commonality and variability between products from a family, and supports the generation of specific products by reusing a set of core family assets. This paper proposes a UML model transformation approach for software product lines to derive a performance model for a specific product. The input to the proposed technique, the "source model", is a UML model of a SPL with performance annotations, which uses two separate profiles: a "product line" profile from literature for specifying the commonality and variability between products, and the MARTE profile recently standardized by OMG for performance annotations. The source model is generic and therefore its performance annotations must be parameterized. The proposed derivation of a performance model for a concrete product requires two steps: a) the transformation of a SPL model to a UML model with performance annotations for a given product, and b) the transformation of the outcome of the first step into a performance model. This paper focuses on the first step, whereas the second step will use the PUMA transformation approach of annotated UML models to performance models, developed in previous work. The output of the first step, named "target model", is a UML model with MARTE annotations, where the variability expressed in the SPL model has been analyzed and bound to a specific product, and the generic performance annotations have been bound to concrete values for the product. The proposed technique is illustrated with an e-commerce case study. Copyright 2008 ACM.

关键词： software design

来源：评论

学校读者我要写书评

暂无评论

Coexistence of real-time and interactive and batch tasks in DVS systems

Coexistence of real-time and interactive and batch tasks in ...

引用

14th IEEE Real-Time and Embedded Technology and Applications Symposium, RTAS 2008

作者： Saewong, Saowanee Rajkumar, Ragunathan Real-Time and Multimedia Systems Laboratory Dept. of Electrical and Computer Engineering Carnegie Mellon University

ISBN: (纸本)0769531466

Interactive and batch tasks typically have aperiodic random demands and arrival patterns. Generally, interactive tasks are assigned high priority for high responsiveness. Batch tasks with less timing criticality are scheduled in background. Unfortunately, most real-time DVS algorithms focus only on the real-time task workload and timing constraints in determining the operating power-optimized clock frequency. This approach can often leave insufficient cycles for servicing interactive and batch tasks and lead to unacceptable tardiness in conventional applications. We present a power-management framework which ensures that conventional applications will obtain acceptable response times and workload throughput without breaking the temporal constraints of real-time tasks that use resource reservation. We propose two solutions: Background-Preserving and Background-On-Demand algorithms. The first scheme is straightforward and increases the clock frequencies of all tasks to accommodate a future non-real-time workload. The second scheme assigns two modes of frequencies to each task, normal mode and turbo mode. The turbo mode is triggered by the presence of a pending non-real-time task in the system. We also provide the integrated versions of both schemes with our dynamic slack reclamation DVS scheme, called the Progressive algorithm. The integrated versions exploit the slack time from underused reserves for saving more power without performance degradation in all applications. © 2008 IEEE.

关键词： Real time systems

来源：评论

学校读者我要写书评

暂无评论

Memory efficient recognition of specific objects with local features

Memory efficient recognition of specific objects with local ...

引用

作者： Kise, Koichi Noguchi, Kazuto Iwamura, Masakazu Dept. of Computer Science and Intelligent Systems Graduate School of Engineering Osaka Prefecture University Japan

ISBN: (纸本)9781424421756

Balancing the recognition rate, processing time and memory requirement is an important issue for object recognition based on local features. For the task of recognizing not generic but specific objects (object instances), a larger number of local features enable us to improve the recognition rate but pose a problem of processing time and memory requirement. For the problem of processing time, approximate nearest neighbor search is known to be extremely effective. In this paper, we propose a method of memory reduction by applying scalar quantization to local features. From experimental results on 100,000 images, we have found that the scalar quantization is of great help;As compared to the original representation with 16 bit/dimension, the recognition rate of 98.1% was kept unchanged using the representation with 2 bit/dim. © 2008 IEEE.

关键词： Object recognition

来源：评论

学校读者我要写书评

暂无评论

Semantic keyword detection of web document

Semantic keyword detection of web document

引用

2008 International Conference on Semantic Web and Web Services, SWWS 2008

作者： Hwang, Myunggwon Yi, Hongryoul Choi, Junho Cho, Miyoung Shin, Jungpil Chung, Ilyong Kim, Pankoo Intelligent Computing Laboratory Chosun University Gwangju Korea Republic of Dept. of Computer Software University of Aizu Aizuwakamatsu Japan Dept. of Computer Engineering Chosun University Gwangju Korea Republic of

ISBN: (纸本)1601320892

This paper deals with a method for semantic keyword detection of web documents. While the document consists of many kinds of part-of-speech, we just consider noun words. We propose a method for measure of relation value that represents relationship between words occurred in the document using WordNet. We calculate concept weight that measures semantic importance of words by using term frequency and relation value together. According to the concept weight, we detect the 10 keywords of document in order. Through experiment, we show that our method is possible to extract main keyword semantically from document.

关键词： Semantic Web

来源：评论

学校读者我要写书评

暂无评论

Cross layer design for RFID/EPC network 08

Cross layer design for RFID/EPC network

引用

International Conference on Mobile Technology, Applications, and systems, Mobility'08

作者： Shih, Frank Y. Chang, Yao-Chung Peng, Min-Chun Lin, Yu-Shan Dept. of Electrical and Computer Engineering New Jersey Institute of Technology United States Dept. of Computer Science and Information Engineering National Taitung University Taiwan Dept. of Information Science and Management Systems National Taitung University Taiwan

ISBN: (纸本)9781605580890

The RFID framework constructed by Reader, Transponder and Middleware system forms a new construction of future production line automation, material management and logistic industry. The EPC (Electronic Product Code) Network, advocated by international organization, EPCglobal Inc., is the standard technology of RFID application. This paper proposes a cross layer design that applies an intelligent mobile purchasing system by combining RFID smart phone at Physical layer, transferring the RFID code into EPC Network at Media Access Control Layer, gathering the EPC Domain Information at Application Layer and establishing the secure EPC network framework with Product of Authority Server (PAS) network environment at Application Layer. By using the cross-layer approach, user can purchase through the smart phone with RFID Reader. Content Web Server and ODS Server are responsible for recording the commodity information by EPC Code. The commodity will be directly sent to user's home through the Object Tracing Function of Secure EPC Network.

关键词： Sales

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：