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IEEE International Symposium on Information Theory

作者： Yi Zhao Bing Qi Xiongfeng Ma Hoi-kwong Lo Li Qian Center for Quantum Information and Quantum Control Department of Physics and Department of Electrical & Computer Engineering University of Toronto Toronto ONT Canada

ISBN: (纸本)142440505X

Decoy state quantum key distribution (QKD) has been proposed as a novel approach to improve dramatically both the security and the performance of practical QKD set-ups. Recently, many theoretical efforts have been made on this topic and have theoretically predicted the high performance of decoy method. However, the gap between theory and experiment remains open. In this paper, we report the first experiments on decoy state QKD, thus bridging the gap. Two protocols of decoy state QKD are implemented: one-decoy protocol over 15 km of standard telecom fiber, and weak+vacuum protocol over 60 km of standard telecom fiber. We implemented the decoy state method on a modified commercial QKD system. The modification we made is simply adding commercial acousto-optic modulator (AOM) on the QKD system. The AOM is used to modulate the intensity of each signal individually, thus implementing the decoy state method. As an important part of implementation, numerical simulation of our set-up is also performed. The simulation shows that standard security proofs give a zero key generation rate at the distance we perform decoy state QKD (both 15 km and 60 km). Therefore decoy state QKD is necessary for long distance secure communication. Our implementation shows explicitly the power and feasibility of decoy method, and brings it to our real-life

关键词： Security Quantum computing Protocols Fiber lasers Laser theory Hydrogen Pulse measurements Physics Telecommunication standards Optical fiber theory

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Experimental Quantum Key Distribution with Decoy States

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Physical Review Letters 2006年第7期96卷 070502-070502页

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

To increase dramatically the distance and the secure key generation rate of quantum key distribution (QKD), the idea of quantum decoys—signals of different intensities—has recently been proposed. Here, we present the first experimental implementation of decoy state QKD. By making simple modifications to a commercial quantum key distribution system, we show that a secure key generation rate of 165 bit/s, which is 1/4 of the theoretical limit, can be obtained over 15 km of a telecommunication fiber. We also show that with the same experimental parameters, not even a single bit of secure key can be extracted with a non-decoy-state protocol. Compared to building single photon sources, decoy state QKD is a much simpler method for increasing the distance and key generation rate of unconditionally secure QKD.

关键词： Quantum theory

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Unconditionally secure key distillation from multiphotons

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Physical Review A 2006年第1期73卷 010302(R)-010302(R)页

作者： Kiyoshi Tamaki 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 Canada M5S 3G4

In this paper, we prove that the unconditionally secure key can be surprisingly extracted from multiphoton emission part in the photon polarization-based quantum key distribution. One example is shown by explicitly proving that one can indeed generate an unconditionally secure key from Alice’s two-photon emission part proposed by Scarani [ et al. Phys. Rev. Lett. 92, 057901 (2004)]. Which is called the Scarani-Acin-Ribordy-Gisin (SARG04) protocol. This protocol uses the same four states as in Bennett-Brassard 1984 (BB84) and differs only in the classical postprocessing protocol. It is, thus, interesting to see how the classical postprocessing of quantum key distribution might qualitatively change its security. We also show that one can generate an unconditionally secure key from the single to the four-photon part in a generalized SARG04 protocol that uses six states. Finally, we also compare the bit error rate threshold of these protocols with the one in the BB84 protocol and the original six-state protocol assuming a depolarizing channel.

关键词： Quantum theory

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Who Moved?! An Investigation into Distribution of Actions and Behaviors in a Multi Agent System

Who Moved?! An Investigation into Distribution of Actions an...

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International Conference on Mechatronics (ICM)

作者： Roozbeh Daneshvar Caro Lucas Artificial Intelligence and Robotics Laboratory Faculty of Electrical and Computer Engineering University of Tehran Tehran Iran Center of Excellence for Control and Intelligent Processing Faculty of Electrical and Computer Engineering School of Intelligent Systems IPM University of Tehran Tehran Iran

In this paper we have considered systems in which agents communicate via their environment. In these systems the agents do not have direct and explicit communication with each other and instead they have implicit communication which is performed via the environment they are located in. Different kinds of environment elements are considered to be changed while on the other hand for all of these situations there is a change in the environment and this change means potential stimuli that fires behaviors of agents for future. It is considered that if we can find a track of changes in the environment and find the roots of a movement in an agent that is originally made by another agent of the group

关键词： Artificial intelligence Intelligent robots Fires Tracking Process control Communication system control control systems Intelligent control Optical computing Intelligent systems

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Transformer winding detailed modeling for protection studies

Transformer winding detailed modeling for protection studies

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IEEE Power India Conference

作者： F. Zhalefar M. Sanaye-Pasand School of Electrical and Computer Engineering University of Tehran Tehran Iran Control and Intelligent Processing Center of Excellence University of Tehran Tehran Iran

Transformer is one of the most sensitive and complex elements of a power system. Nowadays, simulation is a common and effective way for behavior analysis of this element. The main objective in this paper is protective studies of power transformer. In this study a transformer model based on the self and mutual inductances has been proposed. Also a 230/63 kV, 125 MVA transformer with two-winding and three-legged core has been simulated. Obtained simulation studies are compared with test data. Obtained results confirm validity of the developed method

关键词： Windings Power transformers Inductance Transformer cores Magnetic cores Power system modeling Power system protection Power system simulation Testing Earth

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Approximate dynamic programming based on expansive projections

Approximate dynamic programming based on expansive projectio...

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45th IEEE Conference on Decision and control 2006, CDC

作者： Arruda, Edilson F. Do Val, João B. R. Center for Systems and Control National Laboratory for Scientific Computation - LNCC Av. Getulio Vargas 333 Petrópolis RJ 25651-075 Brazil School of Electrical and Computer Engineering State University of Campinas - UNICAMP Caixa Postal 6101 Campinas SP 13083-852 Brazil

ISBN: (纸本)1424401712

We present a general method to obtain convergent approximate value iteration algorithms with function approximation. The result is applicable to any arbitrary approximation architecture and generalizes existing results in the literature derived for particular approximation schemes. Additionally, we show how to obtain a convergent approximate mapping whose fixed point is the projection in the approximation space of a fixed point of the exact dynamic programming mapping with regards to a suitable subset norm. This result relies on evaluating the difference between successive iterates in the selected subset norm, which provides convergent procedures for any arbitrary approximation architecture. ©2006 IEEE.

关键词： Dynamic programming

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Transformer core modeling as applied to slow transients and protective studies

Transformer core modeling as applied to slow transients and ...

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IEEE Power India Conference

Magnetic core has major effects on the response of transformers at low frequencies. For better understanding of transformer behaviors and modeling them accurately, it is necessary to study core behaviors and their effects on transformer current and voltage waveforms. For better studying core behaviors, it is possible to divide total flux of windings into core and air fluxes. In this paper, modeling of core fluxes by employing the principle of duality method is discussed. At the end, a real 230/63 kV, 125 MVA transformer with two winding and three-legged core has been simulated. Obtained simulation results are compared with test results and good agreement between these results are obtained

关键词： Transformer cores Protection Power transformers Magnetic cores Inductance Power system modeling EMTP Power system simulation Capacitance Frequency

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A Time-Invariant Dual High-Gain Based Adaptive Output-Feedback controller for Nonlinear Systems

A Time-Invariant Dual High-Gain Based Adaptive Output-Feedba...

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IEEE Conference on Decision and control

作者： P. Krishnamurthy F. Khorrami Control/Robotics Research Laboratory(CRRL) Department of Electrical and Computer Engineering Six Metrotech Center Polytechnic University Brooklyn NY USA

ISBN: (纸本)1424401704;9781424401703

We propose an adaptive output-feedback controller for a general class of nonlinear triangular (strict-feedback-like) systems. The design is based on our recent results on a dual high-gain observer and controller architecture with a dynamic scaling. The technique provides strong robustness properties and allows the system class to contain unknown functions dependent on all states and involving unknown parameters (with no magnitude bounds required). Unlike our earlier result on this problem where a time-varying design of the high-gain scaling parameter was utilized, the technique proposed here achieves an autonomous dynamic controller by introducing a novel design of the observer, the scaling parameter, and the adaptation parameter. This provides a time-invariant dynamic output-feedback controller for the benchmark open problem proposed in our earlier work with no magnitude bounds or sign information on the unknown parameter being necessary

关键词： Programmable control Adaptive control Nonlinear control systems control systems Nonlinear systems control design Nonlinear dynamical systems Uncertainty Backstepping USA Councils

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Multiscale Face Detection: A New Approach to Robust Face Detection

Multiscale Face Detection: A New Approach to Robust Face Det...

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IEEE International Conference on Fuzzy Systems (FUZZ-IEEE)

作者： M. Aghagolzadeh H. Soltanian-Zadeh B.N. Araabi Department of Electrical and Computer Engineering University of Tehran Tehran Iran Radiologyimageanalaysis laboratory Henry Ford Health System Detroit MI USA Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department University of Tehran Tehran Iran

This paper presents a novel method for detecting multiple frontal faces in still images using multi-scale processing. The main characteristic of this algorithm is its stability in detecting faces with seldom false detections and a high correct detection rate. The novelty of this work comes from the utilization of multiscale detection and using two classifiers to reduce false detections. The algorithm generally has two stages: in the first stage, a face is detected in a unique scale and in the second stage, only the faces that are located in the neighbor scales are accepted as real faces. Consequently, a still image is first resized and scanned block wise, and then each enhanced block is tested for being face. One dimensional Harr wavelet is used for feature extraction, which gives appropriate discriminating features between the face and nonface classes. Detection results at each scale are accumulated in an internal database, so the ultimate detection is prepared based on the mutual detection information between consequent scales. To parameterize both the Bayesian and the simple proposed classifier, 2,643 faces were congregated from famous face databases and more than 10,000 non-face samples were selected from nature images. Experimental results using images gathered from known databases like MIT-CMU show great ability of the proposed algorithm in detecting faces.

关键词： Face detection Robustness Image databases Bayesian methods Humans Application software Stability Feature extraction Spatial databases computer vision

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Fundamental Limitations in Self-Sensing Magnetic Bearings when Modeled as Linear Periodic Systems

Fundamental Limitations in Self-Sensing Magnetic Bearings wh...

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American control Conference

作者： K. S. Peterson R. H. Middleton J. S. Freudenberg School of Mechanical Engineering Purdue University USA Center for Complex Dynamic Systems and Control University of Newcastle Australia Department of Electrical and Engineering and Computer Science University of Michigan USA

In "Magnetic Bearing Measurement Configurations and Associated Robustness and Performance Limitations", Thibeault and Smith demonstrate that self-sensing magnetic bearings are impractical due to fundamental limitations in the achievable closed-loop robustness. Due to experimental data which appeared to contradict these results, Maslen, Montie, and Iwasaki showed that significantly better robustness is achievable in "Robustness limitations in self-sensing magnetic bearings" if the magnetic bearing is modeled as a linear periodic (LP) system rather than the linear time invariant (LTI) system used by Thibeault and Smith. The present paper explores why modeling the self-sensing magnetic bearing as a LP system improves the achievable robustness. This is accomplished by utilizing lifting to analyze the LP model as a MIMO discrete LTI system.

关键词： Magnetic levitation Robustness Magnetic analysis Electromagnets Current measurement Electromagnetic measurements Position measurement Frequency MIMO Feedback

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