检索结果-内蒙古大学图书馆

Annual Conference on Wireless On Demand Network systems and Services (WONS)

作者： Abdalkarim Awad Lei Shi Reinhard German Falko Dressler Computer Networks and Communication Systems Department of Computer Science University of Erlangen Germany

We study the capabilities of virtual addressing schemes for efficient and failure tolerant routing in sensor networks. In particular, we present the virtual cord protocol (VCP) that uses techniques known from peer-to-peer networks, i.e. distributed hash tables (DHTs) are used to associate data items in sensor networks with particular node addresses. The addresses of nodes are dynamically maintained by the protocol to form a virtual cord. VCP uses two mechanisms for finding paths to nodes and associated data items: First, it relies on the virtual cord that always points towards the destination. Furthermore, locally available neighborhood information is exploited for greedy routing. Our simulation results show that VCP is able to find paths close to the possible shortest path with very low overhead. The routing performance of VCP, which clearly outperforms other ad hoc routing protocols such as Dynamic MANET On Demand (DYMO), is similar to other virtual addressing schemes, e.g. Virtual Ring Routing (VRR). However, we improved VCP to handle frequent node failures in an optimized way. The results presented in this paper outline the capabilities of VCP to handle such cases.

关键词： Peer to peer computing Routing protocols Wireless sensor networks Mobile ad hoc networks Sensor systems Memory computer networks computer science Internet Proposals

来源：评论

学校读者我要写书评

暂无评论

A novel accelerometer based on microring resonator

引用

Chinese Optics Letters 2009年第9期7卷 798-801页

作者：莫文琴吴华明郜定山周治平 Wuhan National Laboratory for Optoelectronics College of Optoelectronie Science and Engineering Huazhong University of Science and Technology Faculty of Mechanical and Electronic Information China University of Geosciences Wuhan National Laboratory for Optoelectronics College of Optoelectronic Science and EngineeringHuazhong University of Science and Technology State Key Laboratory on Advanced Optical Communication Systems and Networks Peking University School of Electrical and Computer Engineering Georgia Institute of Technology

A novel microring resonator accelerometer is proposed. It is realized by a suspended straight waveguide coupled with a microring resonator. Under the external acceleration, the coupling coefficient is a function of gap spacing between the two waveguides. The mathematical model of the sensing element is established. Both the finite element method and coupled mode theory are adopted to analyze and optimize the proposed structure. Simulation results show that the mechanical sensitivity is 0.015 μm/g with the working frequency below 500 Hz and cross-axis sensitivity less than 0.001%, which is promising in seismic related applications.

关键词： Accelerometers Mathematical models Waveguides

来源：评论

学校读者我要写书评

暂无评论

Introduction to Model-based Reliability Evaluation of Wireless Sensor networks

引用

IFAC Proceedings Volumes 2009年第5期42卷 134-139页

作者： C. Jäggle J. Neidig T. Grosch F. Dressler Siemens AG Industry Sector Nuremberg Germany Computer Networks and Communication Systems Dept. of Computer Science University of Erlangen Germany

A high level of reliability is a significant requirement for using wireless sensor networks in industrial environments. Model-based evaluation is usually applied in conventional systems to estimate the reliability. In contrast, for analyzing sensor networks, these methods are hardly tested and proven due to the unique properties of that kind of network. This paper presents a first model-based approach to quantitatively assess the reliability of sensor networks. Based on an abstract model of a sensor network, the degree of detail with respect to the characteristic aspects of sensor networks is increased in a stepwise manner. If network topologies are taken into account, analytical methods fail and the assessment of reliability measures has to be done numerically. Finally, a Monte Carlo Simulation is conducted to also cover dynamics in the topology. In conclusion, this paper shows that, by knowledge of link probabilities and lifetime distributions of single sensor nodes, model-based analysis may be used to estimate reliability measures of sensor networks.

关键词： Network reliability Sensor networks Stochastic modeling Monte Carlo Simulation

来源：评论

学校读者我要写书评

暂无评论

A bias free, quantum random number generator

A bias free, quantum random number generator

引用

Frontiers in Optics, FiO 2009

作者： Wei, Wei Guo, Hong CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

Based on the random photon emission of laser diode, we propose a new approach for true random number generation with convenient implementation, which is intrinsically bias free and suitable for high speed applications... 详细信息

ISBN: (纸本)9781557528780

关键词： Random number generation

来源：评论

学校读者我要写书评

暂无评论

Bounding the Number of Relevant Objects in Automotive Environment Perception systems

Bounding the Number of Relevant Objects in Automotive Enviro...

引用

International Conference on Networked Sensing systems

作者： Christoph Lauer Thomas Herpel Reinhard German Jens Pollmer Department of Computer Science 7 Computer Networks and Communication Systems University of Erlangen-Nuremberg Safety Electronics Department Audi AG Ingolstadt

ISBN: (纸本)9781424463138;9781424463145

Multi-sensor data fusion systems for environment perception in the automotive domain are regarded as a promising instrument for obtaining dependable vehicular context information. Sensor data from remote sensing devices like radar or laserscanners is transmitted via intra-car networks to electronic control units (ECU) that enable an intelligent, context sensitive vehicle behavior depending on the current traffic situation. Although new bus systems, such as Flexray, offer increased data rates, the communication resources need to be utilized efficiently. In order to do so, two aspects have to be considered: 1) The size of a single object description and 2) the overall number of perceivable objects. In this paper we focus on the latter of the two aspects. We created a flexible discrete event simulation framework that allows for an in-depth analysis of various aspects of environment perception systems. Our simulation covers scenarios consisting of different sensor-sets, traffic scenarios, fusion benefits, and algorithms for context perception. Using this framework we were able to limit the number of objects a single sensor is allowed to perceive and analyze the impact of this limitation on the overall system performance without such restrictions. Our findings include: 1) Bounding the number of relevant objects to a number between 4-8 does not affect the false negative ratio of the system, 2) the overall error and false positive error ratio does not increase by bounding the number of relevant objects, 3) in safety-relevant environment perception systems the number of relevant objects can be reduced even further without compromising the system integrity, and 4) bounding the number of objects at an early stage of signal processing is superior to a reduction at a late stage of signal processing.

关键词： environmental perception system integrity signal processing object description Vehicle performance System performance communication resources Error analysis

来源：评论

学校读者我要写书评

暂无评论

A novel ellipse model for optically injection-locked VCSELs

A novel ellipse model for optically injection-locked VCSELs

引用

Frontiers in Optics, FiO 2009

作者： Guo, Peng Yang, Weijian Parekh, Devang Chang-Hasnain, Connie J. Department of Electrical Engineering and Computer Sciences University of California Berkeley CA 94720 United States State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

A novel ellipse graphic tool is established based on injection-locked rate equations to analyze the cavity mode behavior of injection-locked vertical-cavity surface-emitting lasers. Calculation based on this model sho... 详细信息

ISBN: (纸本)9781557528780

关键词： Surface emitting lasers

来源：评论

学校读者我要写书评

暂无评论

Tunable group velocity of light propagation and its application

Tunable group velocity of light propagation and its applicat...

引用

2009 Symposium on Photonics and Optoelectronics, SOPO 2009

作者： Yonglan, Hou Chao, Peng Lei, Jia Lixin, Zhu Zhengbin, Li State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing China State Key Joint Laboratory of Integrated Optoelectronics Beijing China

ISBN: (纸本)9781424444113

In this paper, we proposed a novel approach to demonstrate optically controllable pulse group velocity at telecommunication wavelengths in EDF due to CPO. First we reviewed recent advances in slow-light-based optical signal processing, then we study slow and fast light propagation in erbium doped fiber abstractly based on theory and simulation model. It is revealed though the research that the time delay and advancement depends greatly on the pump power, influence of the ion density on the group velocity of light propagation is also studied. Based on our discussion, the optimization parameters should be selected in order to obtain more appropriate time delay and the slowdown of group velocity, which is of great importance to the communication industry. ©2009 IEEE.

关键词： Light velocity

来源：评论

学校读者我要写书评

暂无评论

Microring resonator for glucose sensing applications

引用

Frontiers of Optoelectronics 2009年第3期2卷 304-307页

作者： Yao CHEN Zhengyu LI Huaxiang YI Zhiping ZHOU Jun YU Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology State Key Laboratory on Advanced Optical Communication Systems and Networks Peking University School of Electrical and Computer Engineering Georgia Institute of Technology

Silicon nitride microring resonators were demonstrated as chemical sensors. The microring devices,with diameter of 100 μm, were fabricated using complementary metal oxide semiconductor（CMOS）-compatible technology, and a high Q factor of 15000 was realized with free spectrum range（FSR） of 2 nm. The structures were further packaged to perform as chemical sensors, and their functionality was proved using deionized water（DI water）and ethanol as detecting mediums. Lastly, the packaged chips were used to detect glucose solutions with various concentrations, and a detection capability of refractive index change of 10–3refractive index unit（RIU） was obtained.

关键词： microring resonator chemical sensor glucose sensing refractive index unit (RIU) Q factor

来源：评论

学校读者我要写书评

暂无评论

Anomalous modulation characteristics of optical injection-locked VCSELs

Anomalous modulation characteristics of optical injection-lo...

引用

Asia communications and Photonics Conference and Exhibition, ACP 2009

作者： Guo, Peng Yang, Weijian Parekh, Devang Hofmann, Werner Amann, Markus C. Chang-Hasnain, Connie J. Department of Electrical Engineering and Computer Sciences University of California Berkeley CA 94720 United States State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing 100871 China Walter Schottky Institute Technical University of Munich Am Coulombwall 3 85748 Garching Germany

ISBN: (纸本)9781557528773

An anomalous DC-suppression in the small signal response is observed experimentally and its relationship with data pattern inversion is investigated for the first time. With the inclusion of a novel OIL reflection interference model, excellent agreement is obtained between the experiment results and theoretical analysis. © 2009 Optical Society of America.

关键词： Optical signal processing

来源：评论

学校读者我要写书评

暂无评论

Physical origin of data pattern inversion in optical injection-locked VCSELs

Physical origin of data pattern inversion in optical injecti...

引用

Frontiers in Optics, FiO 2009

作者： Yang, Weijian Guo, Peng Parekh, Devang Hofmann, Werner Amann, Markus C. Chang-Hasnain, Connie J. Department of Electrical Engineering and Computer Sciences University of California Berkeley CA 94720 United States State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing 100871 China Walter Schottky Institute Technical University of Munich Am Coulombwall 3 85748 Garching Germany

The physical origin and criteria for adjustable data pattern inversion in optical injection locked VCSELs are explained with a novel model including the interference effect of master laser reflection. Simulation resul... 详细信息

ISBN: (纸本)9781557528780

关键词： Surface emitting lasers

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：