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Ensemble Kalman filtering for wind field estimation in wind farms

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Ensemble Kalman filtering for wind field estimation in wind ...

American control Conference

作者： B. M. Doekemeijer S. Boersma L. Y. Pao J. W. van Wingerden Delft Center for Systems and Control (DCSC) Faculty of Mechanical Engineering Delft University of Technology Department of Electrical Computer and Energy Engineering (ECEE) University of Colorado Boulder (CU)

ISBN: (纸本)9781509045839

Currently, wind farms typically rely on greedy control, in which the individual turbine's structural loading and power are optimized. However, this often appears suboptimal for the whole wind farm. A promising solution is closed-loop wind farm control using state feedback algorithms employing a dynamic model of the flow. This control method is a novelty in wind farms, and has potential to provide a temporally optimal control policy accounting for time-varying inflow conditions and unmodeled dynamics, both often neglected in current methods. An essential building block for state feedback control is a state estimator (observer) that reconstructs the system states for the dynamic model using a small number of measurements. As computational efficiency is critical in real-time control, lower-fidelity models are proposed to be used. In this work, WindFarmObserver (WFObs) is introduced, which is a state estimator relying on the WindFarmSimulator (WFSim) model and an Ensemble Kalman Filter (EnKF). The states of WFSim form the two-dimensional flow field in a wind farm at hub height. WFObs is tested in a two-turbine setup using a high-fidelity simulation model. With a realistic sensor setup where only 1.1% of the to-be-estimated states are measured, WFObs reduces the RMS error by 21% compared to open-loop simulation of WFSim, at a low computational cost of 0.76 s per timestep, a factor 10~2 faster than the common Extended Kalman Filter.

关键词： Wind farms Kalman filtering ROOT-MEAN-SQUARE ERRORS State estimation state feedback control unmodeled dynamics Flow models Two dimensional flow Wind fields computational efficiency

Information theoretic security of quantum key distribution overcoming the repeaterless secret key capacity bound

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arXiv 2018年

作者： Tamaki, Kiyoshi Lo, Hoi-Kwong Wang, Wenyuan Lucamarini, Marco Graduate School of Science and Engineering for Education University of Toyama Gofuku 3190 Toyama930-8555 Japan Center for Quantum Information and Quantum Control Department of Physics Dept. of Electrical & Computer Engineering University of Toronto TorontoM5S 3G4 Canada Toshiba Research Europe Ltd 208 Cambridge Science Park CambridgeCB4 0GZ United Kingdom

Quantum key distribution is a way to distribute secret keys to distant users with information theoretic security and key rates suitable for real-world applications. Its rate-distance figure, however, is limited by the natural loss of the communication channel and can never surpass a theoretical limit known as point-to-point secret key capacity. Recently, a new type of quantum key distribution with an intermediate relay was proposed to overcome this limit (M. Lucamarini, Z. L. Yuan, J. F. Dynes and A. J. Shields, Nature, 2018). However, a standard application of the decoy state method limited the security analysis of this scheme to hold under restrictive assumptions for the eavesdropper. Hence, overcoming the point-to-point secret key capacity with an information-theoretic secure scheme is still an open question. Here, we propose a novel way to use decoy states to answer this question. The key idea is to switch between a Test mode and a Code mode, the former enabling the decoy state parameter estimation and the latter generating a key through a phase encoding protocol. This way, we confirm the scaling properties of the original scheme and overcome the secret key capacity at long distances. Our work plays a key role to unlock the potential of practical secure quantum communications. Copyright © 2018, The Authors. All rights reserved.

关键词： Quantum cryptography

Random asynchronous iterations in distributed coordination algorithms

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arXiv 2018年

作者： Chen, Yao Xia, Weiguo Cao, Ming Lü, Jinhu Department of Computer Science Southwestern University of Finance and Economics Chengdu611130 China School of Control Science and Engineering Dalian University of Technology Dalian116024 China Faculty of Science and Engineering ENTEG University of Groningen Groningen9747 AG Netherlands School of Automation Science and Electrical Engineering State Key Laboratory of Software Development Environment Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing100191 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China

Distributed coordination algorithms (DCA) carry out information processing processes among a group of networked agents without centralized information fusion. Though it is well known that DCA characterized by an SIA (stochastic, indecomposable, aperiodic) matrix generate consensus asymptotically via synchronous iterations, the dynamics of DCA with asynchronous iterations have not been studied extensively, especially when viewed as stochastic processes. This paper aims to show that for any given irreducible stochastic matrix, even non-SIA, the corresponding DCA lead to consensus successfully via random asynchronous iterations under a wide range of conditions on the transition probability. Particularly, the transition probability is neither required to be independent and identically distributed, nor characterized by a Markov chain. Copyright © 2018, The Authors. All rights reserved.

关键词： Stochastic systems

Reactive power compensation game under prospect-theoretic framing effects

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arXiv 2017年

作者： Wang, Yunpeng Saad, Walid Sarwat, Arif I. Hong, Choong Seon Electrical and Computer Engineering Department University of Miami Coral GablesFL United States Wireless@VT Bradley Department of Electrical and Computer Engineering Virginia Tech BlacksburgVA United States Department of Electrical and Computer Engineering Florida International University MiamiFL United States Department of Computer Engineering Kyung Hee University Korea Republic of Dispatching Control Center State Grid Beijing Electric Power Company China

Reactive power compensation is an important challenge in current and future smart power systems. However, in the context of reactive power compensation, most existing studies assume that customers can assess their compensation value, i.e., Var unit, objectively. In this paper, customers are assumed to make decisions that pertain to reactive power coordination. In consequence, the way in which those customers evaluate the compensation value resulting from their individual decisions will impact the overall grid performance. In particular, a behavioral framework, based on the framing effect of prospect theory (PT), is developed to study the effect of both objective value and subjective evaluation in a reactive power compensation game. For example, such effect allows customers to optimize a subjective value of their utility which essentially frames the objective utility with respect to a reference point. This game enables customers to coordinate the use of their electrical devices to compensate reactive power. For the proposed game, both the objective case using expected utility theory (EUT) and the PT consideration are solved via a learning algorithm that converges to a mixed-strategy Nash equilibrium. In addition, several key properties of this game are derived analytically. Simulation results show that, under PT, customers are likely to make decisions that differ from those predicted by classical models. For instance, using an illustrative two-customer case, we show that a PT customer will increase the conservative strategy (achieving a high power factor) by 29% compared to a conventional customer. Similar insights are also observed for a case with three customers. Copyright © 2017, The Authors. All rights reserved.

关键词： Smart power grids

Corrigendum to “Assessing sustainability of soybean supply in China: Evidence from provincial production and trade data” [J. Clean. Prod. (2020) 245 119006]

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Journal of Cleaner Production 2021年 297卷

作者： Fei Wu Yong Geng Yuquan Zhang Chenxing Ji Yifan Chen Lu Sun Wei Xie Tariq Ali Tsuyoshi Fujita School of Environmental Science and Engineering Shanghai Jiao Tong University Minhang Shanghai 200240 China School of International and Public Affairs Shanghai Jiao Tong University Xuhui Shanghai 200030 China China Institute for Urban Governance Shanghai Jiao Tong University No. 800 Dongchuan Road Minhang Shanghai 200240 China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092 China China-UK Low Carbon College Shanghai Jiao Tong University No.3 Yinlian Road Pudong New Area Shanghai 201306 China Department of Electrical Engineering and Computer Science University of California Irvine Irvine 92629 USA School of Geographic Sciences East China Normal University No. 500 Dongchuan Road Minhang Shanghai 200241 China Center for Social and Environmental Systems Research National Institute for Environmental Studies 16-2 Onogawa Tsukuba Ibaraki 305-8506 Japan Department of Environment Systems Graduate School of Frontier Sciences The University of Tokyo 5-1-5 Kashiwanoha 277-8563 Japan China Center for Agricultural Policy School of Advanced Agricultural Sciences Peking University No.5 Yiheyuan Road Haidian District Beijing 100871 China North China University of Technology No.5 Jinyuanzhuang Road Shijingshan District Beijing 100144 China

Corrections to “Requirements Socio-Technical Graphs for Managing Practitioners’ Traceability Questions”

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IEEE Transactions on computational Social Systems 2019年第1期6卷 190-190页

作者： Nan Niu Wentao Wang Arushi Gupta Mona Assarandarban Li Da Xu Juha Savolainen Jing-Ru C. Cheng Department of Electrical Engineering and Computer Science University of Cincinnati Cincinnati OH USA Old Dominion University Norfolk VA USA Software and Control Research and Development Danfoss Drives A/S 6300 Gråsten Denmark Information Technology Laboratory U.S. Army Engineer Research and Development Center Vicksburg MS USA

In [1] , Li Da Xu’s main affiliation should be Old Dominion University, Norfolk, VA 23529 USA.

关键词： Research and development computer science Software Information technology

Entanglement enhancement in multimode integrated circuits

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Physical Review A 2018年第6期97卷 062303-062303页

作者： Zacharie M. Léger Aharon Brodutch Amr S. Helmy The Edward S. Rogers Department of Electrical and Computer Engineering University of Toronto 10 Kings College Road Toronto Ontario Canada M5S 3G4 Department of Physics University of Toronto 60 St George St Toronto Ontario Canada M5S 1A7 Center for Quantum Information and Quantum Control University of Toronto 60 St George St Toronto Ontario Canada M5S 1A7

The faithful distribution of entanglement in continuous-variable systems is essential to many quantum information protocols. As such, entanglement distillation and enhancement schemes are a cornerstone of many applications. The photon subtraction scheme offers enhancement with a relatively simple setup and has been studied in various scenarios. Motivated by recent advances in integrated optics, particularly the ability to build stable multimode interferometers with squeezed input states, a multimodal extension to the enhancement via photon subtraction protocol is studied. States generated with multiple squeezed input states, rather than a single input source, are shown to be more sensitive to the enhancement protocol, leading to increased entanglement at the output. Numerical results show the gain in entanglement is not monotonic with the number of modes or the degree of squeezing in the additional modes. Consequently, the advantage due to having multiple squeezed input states can be maximized when the number of modes is still relatively small (e.g., four). The requirement for additional squeezing is within the current realm of implementation, making this scheme achievable with present technologies.

关键词： Entanglement manipulation Entanglement production Integrated optics Optical quantum information processing Quantum entanglement Quantum information processing with continuous variables

Secure quantum communication in the presence of phase- and polarization-dependent loss

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arXiv 2018年

作者： Li, Chenyang Curty, Marcos Xu, Feihu Bedroya, Olinka Lo, Hoi-Kwong Center for Quantum Information and Quantum Control Department of Electrical & Computer Engineering Department of Physics University of Toronto TorontoONM5S 3G4 Canada Escuela de Ingeniería de Telecomunicación Department of Signal Theory and Communications University of Vigo VigoE-36310 Spain Shanghai Branch Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Shanghai201315 China

Silicon photonics holds the promise of the miniaturization of quantum communication devices. Recently, silicon chip optical transmitters for quantum key distribution (QKD) have been built and demonstrated experimentally. Nonetheless, these silicon chips suffer substantial phase- and polarization-dependent loss (PDL) which, if unchecked, could compromise the security of QKD systems because of overestimating the secret key rate. Here, we first restore the security by regarding the single photons without phase and polarization dependence as untagged and secure qubits. Next, by using a post-selection technique, one could implement a secure QKD protocol that provides a high key generation rate even in the presence of severe phase and polarization dependent loss. Our solution is simple to realize in a practical experiment as it does not require any hardware modification. Copyright © 2018, The Authors. All rights reserved.

关键词： Quantum cryptography

Entropic energy-time uncertainty relation

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arXiv 2018年

作者： Coles, Patrick J. Katariya, Vishal Lloyd, Seth Marvian, Iman Wilde, Mark M. Theoretical Division Los Alamos National Laboratory Los AlamosNM87545 United States Hearne Institute for Theoretical Physics Department of Physics and Astronomy Louisiana State University Baton RougeLA70803 United States Department of Mechanical Engineering Massachusetts Institute of Technology CambridgeMA02139 United States Research Laboratory of Electronics Massachusetts Institute of Technology CambridgeMA02139 United States Departments of Physics & Electrical and Computer Engineering Duke University DurhamNC27708 United States Center for Computation and Technology Louisiana State University Baton RougeLA70803 United States

Energy-time uncertainty plays an important role in quantum foundations and technologies, and it was even discussed by the founders of quantum mechanics. However, standard approaches (e.g., Robertson's uncertainty relation) do not apply to energy-time uncertainty because, in general, there is no Hermitian operator associated with time. Following previous approaches, we quantify time uncertainty by how well one can read off the time from a quantum clock. We then use entropy to quantify the information-theoretic distinguishability of the various time states of the clock. Our main result is an entropic energy-time uncertainty relation for general time-independent Hamiltonians, stated for both the discrete-time and continuous-time cases. Our uncertainty relation is strong, in the sense that it allows for a quantum memory to help reduce the uncertainty, and this formulation leads us to reinterpret it as a bound on the relative entropy of asymmetry. Due to the operational relevance of entropy, we anticipate that our uncertainty relation will have information-processing applications. Copyright © 2018, The Authors. All rights reserved.

关键词： Entropy