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Plasmonic Corrugated Horn Structure for Optical Transmission Enhancement

Chinese Physics Letters 2009年第12期26卷 122-124页

作者：李光元蔡琳肖峰徐安士 State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronic Engineering and Computer Science Peking University Beijing 100871 Centre of Excellence for MicroPhotonic Systems (COMPS) Electron Science Research Institute Edith Cowan University 270 Joondalup Drive Joondalup WA 6027 Australia

We propose and theoretically analyze a plasmonic corrugated horn structure for enhanced optical transmission. It makes use of the enhancement of unidirectional propagating surface plasmon polaritons at oblique incidence. Geometric parameters such as the groove depth and width are optimized. Analysis shows that it presents a better performance than the bull＇s eye structure for a small number of grooves.

关键词： Chinese climate network complex systems small world community

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A novel accelerometer based on microring resonator

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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

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Ytterbium-doped mode-locked fiber laser at hundreds of kHz repetition rate

Ytterbium-doped mode-locked fiber laser at hundreds of kHz r...

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Conference on Lasers and Electro-Optics, CLEO 2009

作者： Zhou, Chun Chen, Lingling Cai, Yue Zhang, Meng Ren, Ling Li, Peng Zhang, Zhigang Institute of Quantum Electronics State Key Laboratory of Advanced Optical Communication System and Networks School of Electronics Engineering and Computer Science University of Beijing Beijing 100871 China

A long ring-cavity, low repetition rate Yb-doped fiber laser was demonstrated. Pulses with repetition rate of about 381.3 kHz and single pulse energy above 300 nJ were obtained. © 2009 Optical Society of America.

ISBN: (纸本)9781557528698

关键词： Fiber lasers

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Self-localization capable mobile sensor nodes

Self-localization capable mobile sensor nodes

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IEEE International Conference on Technologies for Practical Robot Applications (TePRA)

作者： Juergen Eckert Kemal Koeker Philipp Caliebe Falko Dressler Reinhard German Computer Networks and Communication Systems Department of Computer Science University of Erlangen Germany

ISBN: (纸本)9781424449910

Position sensing systems for indoor environments have one common problem: The setup effort of the whole system. GPS-supported localization is simple and fast to implement and the reference grid is ubiquitous. However, in locations where the signals of GPS are not available, e.g. indoor, or where the technique is not accurate enough, other position sensing systems have to be used. Usually, a reference grid will be provided by an administrator: Reference points must be deployed and programmed with the correct location information. Especially for temporary installations and dynamic surroundings the setup costs are very high. In our work, we developed a robotic platform, which is capable of deploying itself autonomously and which can operate as a mobile reference point equipped with ultra sound transmitters. Relying on a combination of two controllers and an odometry system, the platform is able to drive on a complex spline-like trace using only a few supporting points. We also investigated the problem for the localization system itself. The detection field of our ultra sound based system is a full hemisphere. Within this domain, we can measure the distances between nodes exploiting the time of flight technique as well as the angle of arrival. Finally, the system can also be used as a sonar system for passive obstacles detection.

关键词： Sonar detection Indoor environments Global Positioning System Costs Mobile robots Robot sensing systems Transmitters Control systems Spline Time measurement

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Self-organizing network security environments - A simulative analysis

Self-organizing network security environments - A simulative...

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Eurocon

作者： Falko Dressler Lavanya Poondru Tobias Limmer Reinhard German Computer Networks and Communication Systems Department of Computer Science University of Erlangen Germany

We discuss the need for adaptive load control in network security environments in order to cope with the increasing bandwidth requirements. In earlier work, we developed a simple model to study the behavior of feedback loops for self-configuring security environments. We primarily considered the traffic between the monitoring probes, the IDS systems, and associated firewalls. We now enhanced the model to study fully self-organized network security environments in a simulation model. First simulation results outline both the feasibility of the general approach and the possibilities of the simulation model.

关键词： Self-organizing networks Analytical models Programmable control Adaptive control Load flow control Bandwidth Feedback loop communication system traffic control Traffic control Monitoring

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A differentiated QoS aware multipath routing algorithm for optical burst switched networks

A differentiated QoS aware multipath routing algorithm for o...

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Network Architectures, Management, and Applications VII

作者： Chi, Yuan Zhang, Zhenrong Li, Zhengbin Anshi, Xu State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing China School of Computer Electronics and Information Guangxi University Nanning Guangxi China

ISBN: (纸本)9780819480354

Optical burst switching (OBS) is thought to be the best way to adapt the bursty IP traffic over optical WDM networks. It provides statistical multiplexing gains and avoids long end to end setup time of traditional virtual circuit configuration. However, under the current and foreseeable limitations of optical technology, performance of OBS is mainly hampered at network nodes by burst contention. The contention is serious constraints on the capacity of OBS networks. A leading source of contention is the congestion at congested links where a limited number of wavelengths are shared by a lot of bursts. These congested links are stemming from burst routing algorithms. In this paper, we studied on routing path competition phenomenon. We proposed a differentiated QoS aware multipath routing algorithm for OBS networks. This algorithm is evaluated through extensive numerical studies over a typical topology--the 14-node NSFnet. Results show that it outperforms the existing algorithms in terms of burst blocking probability and link utilization. © 2009 SPIE-OSA-IEEE.

关键词： Optical burst switching

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Advantages of virtual addressing for efficient and failure tolerant routing in sensor networks

Advantages of virtual addressing for efficient and failure t...

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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

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Investigations on smart card-based secure protocols for autenticated key establishment in digital pay-TV systems

Investigations on smart card-based secure protocols for aute...

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2009 8th IEEE International Conference on Cognitive Informatics, ICCI 2009

作者： Jiang, Zheng-Tao Wang, Yong-Bin Yong, Wang Wang, Yu-Min School of Computer Science Communication University of China Beijing 100024 China School of Computer Science Beijing University of Technology Beijing 100022 China National Key Lab. oflntegrated Service Networks Xidian Univ. Xi'an 710071 China

ISBN: (纸本)9781424446421

Interactive TV is a promising technique to realize individualized services besides traditional video broadcasting, such as VOD (Video on Demand), Email on DTV (Digital TV), E-banking. Utilizing return channel (like Internet, mobile communication), many new applications can be established, which promote the value-added services of DTV. For more profound applications, security mechanisms must be deployed to protect the profits of both the content providers and subscribers. This paper presents investigations on the smart card-based secure protocol for user-STB authentication and session key establishment in DTV system. The proposed secure protocol has features of bidirectional authentication, session key secrecy, session key confirmation, forward security, and efficient interval restart, etc. Therefore, the protocol is appropriate for use on secure conditional access and can be referenced easily in future CA systems for value-added applications. © 2009 IEEE.

关键词： Smart cards

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Real-time indoor localization support for four-rotor flying robots using sensor nodes

Real-time indoor localization support for four-rotor flying ...

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International Workshop on Robot Sensing (ROSE)

作者： Juergen Eckert Falko Dressler Reinhard German Computer Networks and Communication Systems Department of Computer Science 7 University of Erlangen Germany

Flying four-rotor robots (quadrocopters) are on-board sensor controlled systems. In comparison to classical monorotor objects (helicopters), quadrocopters can be piloted with a much lower effort. However, lateral drifts can not be compensated only referring to the built-in sensors. The detection of such drifts is strongly necessary for indoor operation - without corrections a quadrocopter would quickly cause a collision. In order to compensate the dislocation, an additional indoor positioning system is needed. In our work, we provide a framework for time-of-flight based localization systems relying on ultrasonic sensors. It is optimized for use in sensor nodes with low computational power and limited memory. Nevertheless, it offers scalability and high accuracy even in case of single erroneous measurements. We implemented the system in our lab using ultrasound sensors that are light enough to be carried around by the flying object. Using this real-time localization system, a position controller can be implemented to maintain a given position or course.

关键词： Robot sensing systems Sensor systems Ultrasonic variables measurement Real time systems Control systems Ultrasonic imaging Helicopters computer networks computer science communication system control

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A bias free, quantum random number generator

A bias free, quantum random number generator

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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

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