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International Conference on Quantum Information, ICQI 2011

作者： Guo, Hong Peng, Xiang Xu, Bingjie CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks Institute of Quantum Electronics School of Electronics Eng. and Computer Science Peking Univ. Beijing 100871 China

We investigate the security of SARG04 protocol with untrusted source. The secure key rate is derived given that several key parameters of the untrusted source are known. Further, a passive scheme is proposed to monito... 详细信息

ISBN: (纸本)9781557529282

关键词： Attenuation coefficient Beam splitters Quantum key distribution Statistics Transmittance Visibility Quantum optics (270.0270) Quantum communications (270.5565)

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Demo: The acoowee-framework

Demo: The acoowee-framework

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International Conference on Distributed Computing in Sensor systems (DCOSS)

作者： Gerhard Fuchs Lorenz Büttner Christoph Damm Mirko Hansen Florian Heisig Tim Seyschab Reinhard German Computer Science Chair for Computer Networks and Communication Systems Universität Erlangen Nürnberg Erlangen Germany

Within the framework of the acoowee-project we want to improve the programming of Wireless Sensor networks (WSNs) by using and adapting the expressiveness of UML2 Activity Diagrams (UADs) to specify the behavior of the WSN. We expect that our proposal can simplify the way of programming the functional behavior of a WSN and so bring the programming closer to domain experts. We develop the acoowee-framework for Sun SPOTs (spots). The user of the acoowee-framework visually programs UADs and saves them. Afterwards, these UADs are converted into scripts and deployed to the spots e.g. over the air. Finally, the interpreter that runs on the spots executes the scripts. In this demo we present the usage of the acoowee-framework by means of a network consisting of 5 spots and a host with a connected base station. We present all steps listed above. Additionally, we show a rule based manipulation of already deployed scripts and give the attendees the possibilities to try this kind of programming by themselves.

关键词： Wireless sensor networks Programming Unified modeling language Sun Runtime Tin Proposals

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A novel PSO based carrier frequency offset estimation technique for Wi-MAX uplink transmissions

A novel PSO based carrier frequency offset estimation techni...

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2011 11th International Conference on Hybrid Intelligent systems, HIS 2011

作者： Al-Humaidan, Fahad M. Rahoof, P.P. Sameer, S.M. Dept. of Information Systems College of Computer Science and Information Technology King Faisal University Al Ahsa-31982 Saudi Arabia Dept. of Communication and Networks College of Computer Science and Information Technology King Faisal University Al Ahsa-31982 Saudi Arabia Department of Electronics and Communication Engineering National Institute of Technology Calicut Kerala 673601 India

ISBN: (纸本)9781457721502

Carrier frequency offset (CFO) estimation is a challenging task in Wi-MAX uplink as it uses orthogonal frequency division multiple access (OFDMA) which demands extremely accurate frequency synchronization. Here each user may experience a different CFO relative to the base station reference carrier and the estimation of them turn out to be a multiple parameter estimation problem. In this paper, we propose a null subcarrier based particle swam optimization (PSO) technique that performs the estimation by minimizing a cost function. As compared to the null subcarrier based grid search algorithm available in the literature, the computational complexity of the proposed technique is very low. The mean square error of the CFO estimator and bit error rate performance of the Wi-MAX base station receiver that employs the proposed estimation method are studied through computer simulations. It has been shown that the proposed technique achieves a better performance than the grid search algorithm at low to medium signal to noise ratio (SNR) where the algorithm reliability really matters. © 2011 IEEE.

关键词： Mean square error

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The memory effect and its implications on Web QoE modeling

The memory effect and its implications on Web QoE modeling

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2011 23rd International Teletraffic Congress, ITC 2011

作者： Hoßfeld, Tobias Biedermann, Sebastian Schatz, Raimund Platzer, Alexander Egger, Sebastian Fiedler, Markus University of Würzburg Institute of Computer Science Department of Communication Networks D-97074 Würzburg Germany Telecommunications Research Center Vienna - Ftw A-1220 Vienna Austria Blekinge Institute of Technology Communication and Computer Systems Research Lab. SE-371 79 Karlskrona Sweden Technische Universität Darmstadt Germany

ISBN: (纸本)9780983628309

Quality of Experience (QoE) has gained enormous attention during the recent years. So far, most of the existing QoE research has focused on audio and video streaming applications, although HTTP traffic carries the majority of traffic in the residential broadband Internet. However, existing QoE models for this domain do not consider temporal dynamics or historical experiences of the user's satisfaction while consuming a certain service. This psychological influence factor of past experience is referred to as the memory effect. The first contribution of this paper is the identification of the memory effect as a key influence factor for Web QoE modeling based on subjective user studies. As second contribution, three different QoE models are proposed which consider the implications of the memory effect and imply the required extensions of the basic models. The proposed Web QoE models are described with a) support vector machines, b) iterative exponential regressions, and c) two-dimensional hidden Markov models. © 2011 ITC.

关键词： Hidden Markov models

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A sender-based TFRC for Saratoga: A rate control mechanism for a space-friendly transfer protocol

A sender-based TFRC for Saratoga: A rate control mechanism f...

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2011 IEEE Aerospace Conference, AERO 2011

作者： Shahriar, Abu Zafar M. Atiquzzaman, Mohammed Ivancic, William D. Wood, Lloyd Computer Science University of Oklahoma Norman OK 73019 United States Satellite Networks and Architectures Branch Communication Technology Division NASA Glenn Research Center Cleveland OH 44135 United States Centre for Communication Systems Research University of Surrey Guildford GU2 7XH United Kingdom

ISBN: (纸本)9781424473502

Saratoga is a protocol for fast file transfers across dedicated links in private networks, using small amounts of feedback for loss recovery. It is in use to download large amounts of imaging data from remote-sensing satellites, where the link environment is highly asymmetric and up-links are constrained. However, Saratoga lacks a rate-control mechanism to allow fair share with co-existing flows for simultaneous competing transfers, or for across the congested Internet where it must coexist fairly with TCP. TFRC, a self-and TCP-Friendly Rate Control mechanism, can be adopted for Saratoga and leverage its existing protocol information. Use of TFRC normally requires significant changes in protocol operation, including additional data in feedback. We design a sender-based TFRC for Saratoga, needing only simple modifications within the sender and using only existing feedback information. This sender-based TFRC is shown to share the bottleneck-bandwidth fairly under various network conditions, allowing Saratoga to be adapted for shared links or for the congested Internet, while still supporting the asymmetric environments that Saratoga was originally developed for. © 2011 IEEE.

关键词： Feedback

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Non-Markovian dynamics without using a quantum trajectory

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Physical Review A 2011年第5期83卷 052116-052116页

作者： Chengjun Wu Yang Li Mingyi Zhu Hong Guo []CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

Open quantum systems interacting with structured environments is important and manifests non-Markovian behavior, which was conventionally studied using a quantum trajectory stochastic method. In this paper, by dividing the effects of the environment into two parts, we propose a deterministic method without using a quantum trajectory. This method is more efficient and accurate than the stochastic method in most Markovian and non-Markovian cases. We also extend this method to the generalized Lindblad master equation.

关键词： QUANTUM theory MARKOV spectrum DIOPHANTINE approximation PARITY (Physics) NUCLEAR science

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The Investigation on the 1.53µm Photoluminescence of Magnetron-Sputtered Er0.2Re1.8Si2O7 (Re=Yb, Y) Thin Films

The Investigation on the 1.53µm Photoluminescence of Magnet...

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Photonics and Optoelectronics, SOPO

作者： Bing Wang Ge Yuan Lei Wang Ruimin Guo Xingjun Wang Zhiping Zhou State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing China

The photoluminescence (PL) and decay time at 1.53μm of sputtered Er 0.2 Re 1.8 Si 2 O 7 (Re=Yb, Y) thin films were investigated. The enhancement of the PL at 974nm pumping in the Er 0.2 Re 1.8 Si 2 O 7 film was dem... 详细信息

关键词： Films Erbium Ions Laser excitation Sputtering Annealing Silicon

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Efficient free-space optical coupler into dielectric waveguide with great field enhancement

Efficient free-space optical coupler into dielectric wavegui...

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International Conference on Information Photonics and Optical communications (IPOC)

作者： Guangyuan Li Kun Li Lin Cai Anshi Xu State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University Beijing China

We propose an efficient optical coupler to launch free-space signals into a dielectric dielectric waveguide via plasmonic structures with great field enhancement. A plasmonic concentrator composed of a subwavelength slit surround by periodic grooves is used to access and collect free-space light. The transmitted light is then unidirectional directed into a dielectric waveguide with a plasmonic Bragg reflector and a directional coupler. The free-space optical coupler is useful as it combines the plasmonic structure for optical signal access in subwavelength scale with the ultra-low loss dielectric waveguide for long-distance signal transmission and processing making use of nonlinearity.

关键词： Optical waveguides Plasmons Dielectrics Optical reflection Optical coupling Films Couplings

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Entanglement and quantum discord dynamics of two atoms under practical feedback control

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Physical Review A 2011年第1期84卷 012316-012316页

作者： Yang Li Bin Luo Hong Guo []CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science and Center for Computational Science and Engineering (CCSE) Peking University Beijing 100871 People’s Republic of China

We study the dynamics of two identical atoms resonantly coupled to a single-mode cavity under practical feedback control, and focus on the detection inefficiency. The entanglement is induced to vanish in finite time by the inefficiency of detection. Counterintuitively, the asymptotic entanglement and quantum discord can be increased by the inefficiency of detection. The noise of detection triggers the control field to create entanglement and discord when no photons are emitted from the atoms. Furthermore, sudden change happens to the dynamics of entanglement.

关键词： QUANTUM theory PHOTONS ATOMS NOISE FEEDBACK control systems

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Continuous-variable quantum key distribution with Gaussian source noise

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Physical Review A 2011年第5期83卷 052304-052304页

作者： Yujie Shen Xiang Peng Jian Yang Hong Guo []CREAM Group State Key Laboratory of Advanced Optical Communication Systems and Networks (Peking University) and Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University Beijing 100871 PR China

Source noise affects the security of continuous-variable quantum key distribution (CV QKD) and is difficult to analyze. We propose a model to characterize Gaussian source noise through introducing a neutral party (Fred) who induces the noise with a general unitary transformation. Without knowing Fred’s exact state, we derive the security bounds for both reverse and direct reconciliations and show that the bound for reverse reconciliation is tight.

关键词： GAUSSIAN distribution GAUSSIAN beams BEAM optics DISTRIBUTION (Probability theory) NUCLEAR physics

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