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Random Bipartite Entanglement from W and W-Like States

Physical Review Letters 2007年第26期98卷 260501-260501页

作者： Ben Fortescue Hoi-Kwong Lo Center for Quantum Information and Quantum Control Department of Electrical and Computer Engineering and Department of Physics University of Toronto Toronto Ontario M5S 3G4 Canada

We describe a protocol for distilling maximally entangled bipartite states between random pairs of parties from those sharing a tripartite W state |W⟩=(1/3)(|100⟩+|010⟩+|001⟩)ABC, and show that the total distillation rate Et∞ [the total number of Einstein-Podolsky-Rosen (EPR) pairs distilled per W, irrespective of who shares them] may be done at a higher rate than EPR distillation between specified pairs of parties. Specifically, the optimal rate for distillation to specified parties has been previously shown to be 0.92 EPR pairs per W, while our protocol can asymptotically distill 1 EPR pair per W between random pairs of parties, which we conjecture to be optimal. We thus demonstrate a tradeoff between overall distillation rate and final distribution of EPR pairs. We further show that there exist states with fixed lower-bounded Et∞, but arbitrarily small distillable entanglement for specified parties.

关键词： Quantum theory

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Discrete rotational symmetry and quantum-key-distribution protocols

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Physical Review A 2007年第3期75卷 032341-032341页

作者： David Shirokoff Chi-Hang Fred Fung Hoi-Kwong Lo Center for Quantum Information and Quantum Control Department of Electrical & Computer Engineering and Department of Physics University of Toronto Toronto Ontario Canada M5S 3G4

We study the role of discrete rotational symmetry in the quantum key distribution by generalizing the well-known Bennett-Brassard 1984 and Scarani-Acin-Ribordy-Gisin 2004 protocols. We observe that discrete rotational symmetry results in the protocol’s invariance to continuous rotations, thus leading to a simplified relation between bit and phase error rates and consequently a straightforward security proof.

关键词： Network protocols

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Quantum key distribution with dual detectors

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Physical Review A 2007年第5期75卷 052304-052304页

作者： Bing Qi Yi Zhao Xiongfeng Ma Hoi-Kwong Lo Li Qian Center for Quantum Information and Quantum Control (CQIQC) Department of Physics and Department of Electrical and Computer Engineering University of Toronto Toronto M5S 3G4 Canada

To improve the performance of a quantum-key-distribution (QKD) system, high speed, low dark count single photon detectors (or low-noise homodyne detectors) are required. However, in practice, a fast detector is usually noisy. Here, we propose a dual-detector method to improve the performance of a practical QKD system with realistic detectors: the legitimate receiver randomly uses either a fast (but noisy) detector or a quiet (but slow) detector to measure the incoming quantum signals. The measurement results from the quiet detector can be used to bound the eavesdropper’s information, while the measurement results from the fast detector are used to generate a secure key. We apply this idea to various QKD protocols. Simulation results demonstrate significant improvements of the secure key rate in the lower loss regime in both Bennett-Brassard 1984 (BB84) protocol with ideal single photon source and Gaussian-modulated coherent states protocol; while for decoy-state BB84 protocol with weak coherent source, the improvement is moderate. We also discuss various practical issues in implementing the dual-detector scheme.

关键词： Quantum theory

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A Study On Iterative Learning control With Adjustment Of Learning Interval For Monotone Convergence In The Sense Of Sup-Norm

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Asian Journal of control 2008年第1期4卷

作者： Kwang-Hyun Park Zeungnam Bien Division of EE Department of EECS Korea Advanced Institute of Science and Technology 373–1 Kusong-dong Yusong-gu Taejon 305–701 Korea. Zeungname Bien:received the B.S. degree in electronics engineering from Seoul National University Seoul Korea in 1969 and the M.S. and Ph.D. degrees in electrical engineering from the University of Iowa Iowa City Iowa U.S.A. in 1972 and 1975 respectively. During 1976–1977 academic years he taught as assistant professor at the Department of Electrical Engineering University of Iowa. Then Dr. Bien joined Korea Advanced Institute of Science and Technology summer 1977 and is now Professor of Control Engineering at the Department of Electrical Engineering and Computer Science KAIST. Dr. Bien was the president of the Korea Fuzzy Logic and Intelligent Systems Society during 1990–1995 and also the general chair of IFSA World Congress 1993 and for FUZZ-IEEE99 respectively. He is currently co-Editor-in-Chief for International Journal of Fuzzy Systems (IJFS) Associate Editor for IEEE Transactions on Fuzzy Systems and a regional editor for the International Journal of Intelligent Automation and Soft Computing. He has been serving as Vice President for IFSA since 1997 and is now Chief Chairman of Institute of Electronics Engineers of Korea and Director of Humanfriendly Welfare Robot System Research Center. His current research interests include intelligent control methods with emphasis on fuzzy logic systems service robotics and rehabilitation engineering and large-scale industrial control systems. Kwang-Hyun Park:received the B.S. M.S. and Ph.D. degrees in electrical engineering and computer science from KAIST Korea in 1994 19997 and 2001 respectively. He is now a researcher at Human-friendly Welfare Robot System Research Center. His research interests include learning control machine learning human-friendly interfaces and service robotics.

It has been found that some huge overshoot in the sense of sup-norm may be observed when typical iterative learning control (ILC) algorithms are applied to LTI systems, even though monotone convergence in the sense of λ-norm is guaranteed. In this paper, a new ILC algorithm with adjustment of learning interval is proposed to resolve such an undesirable phenomenon, and it is shown that the output error can be monotonically converged to zero in the sense of sup-norm when the proposed ILC algorithm is applied. A numerical example is given to show the effectiveness of the proposed algorithm.

关键词： Iterative learning control monotone convergence learning interval sup-norm

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A Bayesian approach to conceptualization using reinforcement learning

A Bayesian approach to conceptualization using reinforcement...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Saeed Amizadeh Majid Nili Ahmadabadi Babak N. Araabi Roland Siegwart Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department University of Tehran Tehran Iran ASL ETHZ Zurich Switzerland

Abstraction provides cognition economy and generalization skill in addition to facilitating knowledge communication for learning agents situated in real world. Concept learning introduces a way of abstraction which maps the continuous state and action spaces into entities called concepts. Of computational concept learning approaches, action-based conceptualization is favored because of its simplicity and mirror neuron foundations in neuroscience. In this paper, a new biologically inspired concept learning approach based on the Bayesian framework is proposed. This approach exploits and extends the mirror neuron's role in conceptualization for a reinforcement learning agent in nondeterministic environments. In the proposed method, an agent sequentially learns the concepts from both of its successes and its failures through interaction with the environment. These characteristics as a whole distinguish the proposed learning algorithm from positive sample learning. Simulation results show the correct formation of concepts' distributions in perceptual space in addition to benefits of utilizing both successes and failures in terms of convergence speed as well as asymptotic behavior. Experimental results, on the other hand, show the applicability and effectiveness of our method for a real robotic task such as wall-following.

关键词： Bayesian methods Learning Mirrors Neurons Decision making Orbital robotics Uncertainty Encoding Biological information theory Signal processing

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A Dynamic Decoupling control Approach and Its Applications to Chemical Processes

A Dynamic Decoupling Control Approach and Its Applications t...

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American control Conference (ACC)

作者： Qing Zheng Zhongzhou Chen Zhiqiang Gao Center for Advanced Control Technologies Department of Electrical and Computer Engineering Cleveland State University Cleveland OH USA Department of Chemical Engineering University of Massachusetts Amherst MA USA

In this paper, a unique dynamic decoupling control strategy, based on the active disturbance rejection control framework, is proposed for square multivariable systems. With the proposed method, it is shown that a largely unknown square multivariable system is readily decoupled by actively estimating and rejecting the effects of both the internal plant dynamics and external disturbances. By requiring as little information on plant model as possible, the intention is to make the new method practical. Simulation results obtained on two chemical process problems show good performance in the presence of significant unknown disturbances and unmodeled dynamics.

关键词： Chemical processes MIMO control systems Uncertainty Aerospace control Chemical industry electrical equipment industry Cities and towns USA Councils Mathematical model

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Experimental study on the Gaussian-modulated coherent-state quantum key distribution over standard telecommunication fibers

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Physical Review A 2007年第5期76卷 052323-052323页

作者： Bing Qi Lei-Lei Huang Li Qian Hoi-Kwong Lo Center for Quantum Information and Quantum Control (CQIQC) Department of Physics and Department of Electrical and Computer Engineering University of Toronto Toronto Ontario Canada M5S 3G4

In this paper, we present a fully fiber-based one-way quantum-key-distribution (QKD) system implementing the Gaussian-modulated coherent-state (GMCS) protocol. The system employs a double Mach-Zehnder interferometer (MZI) configuration in which the weak quantum signal and the strong local oscillator (LO) go through the same fiber between Alice and Bob, and are separated into two paths inside Bob’s terminal. To suppress the LO leakage into the signal path, which is an important contribution to the excess noise, we implemented a scheme combining polarization and frequency multiplexing, achieving an extinction ratio of 70 dB. To further minimize the system excess noise due to phase drift of the double MZI, we propose that, instead of employing phase feedback control, one simply let Alice remap her data by performing a rotation operation. We further present noise analysis both theoretically and experimentally. Our calculation shows that the combined polarization and frequency multiplexing scheme can achieve better stability in practice than the time-multiplexing scheme, because it allows one to use matched fiber lengths for the signal and the LO paths on both sides of the double MZI, greatly reducing the phase instability caused by unmatched fiber lengths. Our experimental noise analysis quantifies the three main contributions to the excess noise, which will be instructive to future studies of the GMCS QKD systems. Finally, we demonstrate, under the “realistic model” in which Eve cannot control the system within Bob’s terminal, a secure key rate of 0.3bit∕pulse over a 5km fiber link. This key rate is about two orders of magnitude higher than that of a practical Bennett-Brassard 1984 protocol QKD system.

关键词： Quantum cryptography

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Aeromems Wall Hot-Wire Sensor Arrays on Polyimide with Through Foil Vias and Bottom Side electrical Contacts

Aeromems Wall Hot-Wire Sensor Arrays on Polyimide with Throu...

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International Conference on Solid State Sensors and Actuators (TRANSDUCERS)

作者： U. Buder L. Henning A. Neumann E. Obermeier Microsensor & Actuator Technology Center Faculty of Electrical Engineering and Computer Science Technical University Berlin Berlin Germany Measurement and Control Group Faculty of Process Sciences and Engineering Technical University Berlin Berlin Germany Center of Advanced Packaging Faculty of Electrical Engineering and Computer Science Technical University Berlin Berlin Germany

Design and manufacturing of linear arrays consisting of forty MEMS wall-hot wires on a flexible substrate featuring through foil vias and bottom side electrical contacts are presented. Realization of through foil contacts featuring a resistance of less than 0.1 Ω is based on a specifically developed process consisting of laser-"drilling" and sputtering, which is presented in detail. Measurements conducted on a flat plate in a wind tunnel demonstrate the sophistication of the system as sensor induced flow disturbances can not be detected. The sensor system presented therefore is an ideal tool to investigate sensitive flow phenomena like transition and separation.

关键词： Sensor arrays Polyimides Sensor systems Flexible manufacturing systems Micromechanical devices Wires Electric resistance Contact resistance Laser transitions Drilling

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Active Disturbance Rejection control of Chemical Processes

Active Disturbance Rejection Control of Chemical Processes

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IEEE Conference on control Technology and Applications (CCTA)

作者： Zhongzhou Chen Qing Zheng Zhiqiang Gao Department of Chemical Engineering University of Massachusetts Amherst Amherst MA USA The Center for Advanced Control Technologies Department of Electrical and Computer Engineering Cleveland State University Cleveland OH USA

In this paper a novel control strategy, the active disturbance rejection control (ADRC), is applied to the representative process control problems. In the ADRC framework, the disturbance and unmeasured dynamics associated with chemical processes are treated as an additional state variable, which is then estimated and compensated for in real time. This reduces a normally complex, time-varying, nonlinear, and uncertain dynamic process to an approximately linear, time-invariant, cascade-integral form, where a simple proportional-derivative (PD) controller suffices. Simulation studies are performed on two nonlinear continuous stirred tank reactors (CSTR), both demonstrate very good performance in the absence of an accurate mathematical model of the process.

关键词： Process control Chemical processes control systems State estimation Proportional control PD control Three-term control Pi control Aerospace control Nonlinear dynamical systems

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A Hierarchical Clustering Based on Mutual Information Maximization

A Hierarchical Clustering Based on Mutual Information Maximi...

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IEEE International Conference on Image Processing

作者： M. Aghagolzadeh H. Soltanian-Zadeh B. Araabi A. Aghagolzadeh Control and Intelligent Processing Center of Excellence Department of Electrical and Computer Engineering University of Tehran Tehran Iran Radiology Image Analysis Laboratory Henry Ford Health System Detroit MI USA Faculty of Electrical and Computer Engineering University of Tabriz Tabriz Iran

Mutual information has been used in many clustering algorithms for measuring general dependencies between random data variables, but its difficulties in computing for small size datasets has limited its efficiency for clustering in many applications. A novel clustering method is proposed which estimates mutual information based on information potential computed pair-wise between data points and without any prior assumptions about cluster density function. The proposed algorithm increases the mutual information in each step in an agglomerative hierarchy scheme. We have shown experimentally that maximizing mutual information between data points and their class labels will lead to an efficient clustering. Experiments done on a variety of artificial and real datasets show the superiority of this algorithm, besides its low computational complexity, in comparison to other information based clustering methods and also some ordinary clustering algorithms.

关键词： Mutual information Clustering algorithms Clustering methods Data mining Data structures Density functional theory computational complexity Entropy Higher order statistics Probability density function

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