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arXiv 2017年

作者： Sun, Ke Esnaola, Iñaki Perlaza, Samir M. Vincent Poor, H. Dept. of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom Lyon France Dept. of Electrical Engineering Princeton University PrincetonNJ08544 United States

Gaussian random attacks that jointly minimize the amount of information obtained by the operator from the grid and the probability of attack detection are presented. The construction of the attack is posed as an optimization problem with a utility function that captures two effects: firstly, minimizing the mutual information between the measurements and the state variables;secondly, minimizing the probability of attack detection via the Kullback-Leibler divergence between the distribution of the measurements with an attack and the distribution of the measurements without an attack. Additionally, a lower bound on the utility function achieved by the attacks constructed with imperfect knowledge of the second order statistics of the state variables is obtained. The performance of the attack construction using the sample covariance matrix of the state variables is numerically evaluated. The above results are tested in the IEEE 30-Bus test system. Copyright © 2017, The Authors. All rights reserved.

关键词： Information theory

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Maintaining high level information security in enterprises using event correlation

UPB Scientific Bulletin, Series C: Electrical Engineering an...

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UPB Scientific Bulletin, Series C: Electrical engineering and Computer Science 2016年第1 1期78 78卷 73-86页

作者： VlǍdescu, Marius Sgârciu, Valentin Dept. of Automatic Control and System Engineering University Politehnica of Bucharest Romania

This paper presents measures for ensuring high level information security for enterprise systems. These mechanisms are based on the correlation of the events with risk factor, collected from the security systems deployed in the company's infrastructure. The role of event correlation systems is to detect real time security threats and to notify security personnel about those breaches, in order to take measures to reduce the impact of the threat. Our personal contributions in this field consist in creating correlation rules meant to ensure enterprise sensitive data confidentiality inside the company, mostly compromised by employees, and to secure industrial processes targeted by worms. We are also extending the functionality of the event correlation systems from alerting capabilities to real time response capabilities. Also, we conceived additional measures to secure the correlator, which involve approval workflows and encryption techniques.

关键词： Cryptography

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Event-based selective control strategy for raceway reactor: A simulation study

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IFAC-PapersOnLine 2016年第7期49卷 478-483页

作者： Pawlowski, A. Frenández, I. Guzmán, J.L. Berenguel, M. Acién, F.G. Dormido, S. Dept. of Computer Science and Automatic Control UNED Madrid Spain Dept. of Computer Science University of Almería ceiA3 CIESOL Almería Spain Dept. of Chemical Engineering University of Almería ceiA3 CIESOL Almer´ia Spain

This work presents a simulation study of an event-based selective control strategy for a raceway reactor. The control system aims are to maintain simultaneously a pH and dissolved oxygen within specific limits. In the analyzed control scheme, the pH value is prioritized over the dissolved oxygen, since it has a critical influence on the process performance. Besides, the dissolved oxygen also influences the photosynthesis rate and should be kept within the limits. The control structure is evaluated through simulation, where a nonlinear model for microalgae culture in the raceway photobioreactor is used. Analysis of different configurations allows to determine the most adequate control system setup to achieve the desired goals. The obtained results show that combination of an event-based approach with selective control allows to increase the overall productivity as well as to address effective CO2utilization and aeration system energy minimization. © 2016

关键词： Dissolved oxygen Algae control systems Dissolution Microorganisms Dissolved oxygen control Micro algae PH control raceway reactor Selective control

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Optimality analysis of if-conversion transformation

Optimality analysis of if-conversion transformation

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24th High Performance Computing Symposium, HPC 2016, Part of the 2016 Spring Simulation Multi-Conference, SpringSim 2016

作者： Elkhouly, Reem El-Mahdy, Ahmed Elmasry, Amr Alexandria Egypt Dept. of Computer Engineering and Automatic Control Tanta University Tanta Egypt Dept. of Computer Engineering and Systems Alexandria University Alexandria Egypt

ISBN: (纸本)9781510824256

control-flow dependence has always been posited as a substantial dilemma against program acceleration. With the availability of instruction-level parallel architectures, ifconversion optimization has become pivotal for extracting parallelism from serial programs. While many if-conversion optimization heuristics have been proposed in the literature, few of them investigated the proximity to optimality paying more concern to the input program subjectively. In this paper, we study the effectiveness of the LLVM if-conversion transformation using a broad range optimality analysis technique. The whole optimization space of branch instructions within an arbitrarily selected hotspot function of a program is analyzed, tackling the best-performing combination sequence of converted or non-converted branches. In order to precisely observe the influence of selectively converted branches we magnify individual function call and study the behavior with different call circumstances and input data detecting the impact of data size and distribution. We implemented our technique on LLVM 3.6.1 compilation infrastructure and experimented on several representative kernels of the SPEC-CPU2006 vl.l benchmarks suite running on a multicore system of Intel(R) Xeon(R) 3.50GHz processors. Our findings show a performance gain up to 22.7% at the best optimization over the standard optimized code, indicating the need for more aggressive compilation optimization that is able to capture the individual characteristics of every branch. © 2016 Society for Modeling & Simulation International (SCS).

关键词： Optimization

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Event-based internal model control approach for frequency deviation control in islanded micro grid

Event-based internal model control approach for frequency de...

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International Conference on Emerging Technologies and Factory Automation (ETFA)

作者： R. Vilanova C. Pedret M. Barbu O. Arrieta Deptartment of Telecomunications and Systems Engineering Universitat Autonoma Barcelona Bellaterra Barcelona Spain Dept. Automatic Control and Electrical Eng. Dunarea de Jos University of Galati Galati Romania 2Department of Automatic Control University of Costa Rica San Jose Costa Rica

This work faces the problem of frequency deviation in microgrid systems. The considered microgrid includes renewable energy sources such as wind and solar photovoltaic. As long as these sources provide an irregular power supply or there is a sudden change in the system load, the power system frequency deviates. In order to compensate such deviations, alternative, conventional energy sources should be commanded in order to provide the corresponding power deficit. In this paper a very simple and of common industrial practice control approach such as the Internal Model control based on first order plus time delay models is proposed within an event-based framework. As the commanded energy sources are based on fuel consumption, the control usage has to be maintained at low levels. It is shown that the event-based approach is able to provide accurate frequency deviation control with very low movements for the control signal. Time domain simulations show the effectiveness of the approach as compared with other more sophisticated controllers already proposed in the literature.

关键词： Renewable energy sources Generators Microgrids Solar power generation Load modeling Process control Uncertainty

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Design of a bidirectional DC/DC converter with coupled inductor for an electric vehicle application

Design of a bidirectional DC/DC converter with coupled induc...

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IEEE International Symposium on Industrial Electronics (ISIE)

作者： Catalina González-Castaño Enric Vidal-Idiarte Javier Calvente Automatic Control and Industrial Electronics Group (GAEI) Universitat Rovira I Virgili Avinguda dels Paisos Catalans Spain Dept. of Electronics Engineering Universitat Rovira I Virgili

The aim of this work is to design and implement a bidirectional buck-boost converter prototype to regulate DC voltage in a powertrain of an electric vehicle. To validate the design of the proposed converter start-up transient experiments are realized in open loop for the buck and boost mode. The activation signals of MOSFETS switch are generated using a transition method by hysteresis and are implemented in micro-controller. Experimental results show its works properly in both modes, keeping the criteria design parameters.

关键词： Erbium Transient analysis Bandwidth Mechanical power transmission Steady-state Batteries Electric motors

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Preserving data-privacy with added noises: Optimal estimation and privacy analysis

arXiv

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arXiv 2017年

作者： He, Jianping Cai, Lin Guan, Xinping Dept. of Automation Shanghai Jiao Tong University Key Laboratory of System Control and Information Processing Ministry of Education of China Shanghai China Dept. of Electrical & Computer Engineering University of Victoria BC Canada

Networked systems often relies on distributed algorithms to achieve a global computation goal with iterative local information exchanges between neighbor nodes. To preserve data privacy, a node may add a random noise to its original data for information exchange at each iteration. Nevertheless, a neighbor node can estimate other’s original data based on the information it received. The estimation accuracy and data privacy can be measured in terms of (ϵ, δ)-data-privacy, defined as the probability of ϵ-accurate estimation (the difference of an estimation and the original data is within ϵ) is no larger than δ (the disclosure probability). How to optimize the estimation and analyze data privacy is a critical and open issue. In this paper, a theoretical framework is developed to investigate how to optimize the estimation of neighbor’s original data using the local information received, named optimal distributed estimation. Then, we study the disclosure probability under the optimal estimation for data privacy analysis. We further apply the developed framework to analyze the data privacy of the privacy-preserving average consensus algorithm and identify the optimal noises for the algorithm. Copyright © 2017, The Authors. All rights reserved.

关键词： Iterative methods

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An experimental study of quasi-synchronous multiuser communications in cluttered scenarios at low VHF

An experimental study of quasi-synchronous multiuser communi...

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International Conference on Military Communications and Information systems (ICMCIS)

作者： Fikadu T. Dagefu Gunjan Verma Predrag Spasojevic Brian M. Sadler Electrical Engineering Dept. King Mongkut's Institute of Technology Ladkrabang Bangkok Thailand Power System Control Department Metropolitan Electricity Authority Bangkok Thailand

ISBN: (纸本)9781538638590

Reliable, ad hoc communication among multiple users is a crucial objective in complex tactical scenarios. A major challenge is that synchronization mechanisms (such as GPS) are intermittent and fixed centralized coordinators (e.g., base stations) are infeasible. Classical approaches to multiuser communications relying on tight time synchronization and/or power control are impractical in such scenarios. Furthermore, state-of-the-art systems operating at microwave frequencies suffer from lack of penetration and multipath effects causing significant channel variability and exacerbating the near-far effect. In this paper, we investigate the potential advantages of the favorable channel characteristics of the lower VHF band for reliable multiuser communications in highly cluttered environments among near ground nodes. We focus on a class of code division multiple access (CDMA) strategies known as quasi-synchronous (QS) direct sequence (DS) CDMA and use moderate to high QAM constellations. A key aspect of QS CDMA codes is their robustness to coarse inter-user time synchrony and power mismatch, which greatly relaxes the rate that nodes must re-synchronize with each other. Our study experimentally explores the possibilities of multiuser communications in harsh environments among near-ground nodes. Our measurements involve three canonic indoor-to-outdoor, indoor-to-indoor and through-building channels characterized by obstacles and clutter that represent very difficult propagation environments, especially at microwave frequencies. We also study the spatial and temporal variability of our system and characterize the impact of frequency offset on code orthogonality with simulations and experiments. We show that our system has strong potential for excellent multiuser performance in infrastructure-poor regimes.

关键词： Signal to noise ratio Interference Global Positioning system Simulation Delays Semiconductor device measurement Power measurement

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Towards an intelligent reconfigurable BLDC motor controller: Commutation configuration and parameters detection

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AIP Conference Proceedings 2019年第1期2187卷

作者： Agus Mukhlisin Estiko Rijanto I. Nyoman Sutantra Muhammad Nur Yuniarto Agus Sigit Pramono 1Sepuluh Nopember Institute of Technology Department of Mechanical Engineering Surabaya Indonesia 2Research Center for Electrical Power and Mechatronics Indonesian Institute of Sciences LIPI Indonesia 3Design Laboratory Mechanical Eng. Dept. Institut Teknologi Sepuluh Nopember Surabaya Indonesia 4Sepuluh Nopember Institute of Technology Center of Automotive Control System IPTEK Surabaya Indonesia

One of the key components in an electric vehicle is brushless direct current (BLDC) motor controller. At present, it is difficult to match a self-made motor controller with several different BLDC motors available in the global market. One of the reasons is that the Hall sensors’ configuration is not well informed. Another reason is the motor parameter’s values used in the controller are not well suited with the real physical conditions of the motor. This study aims to design an intelligent reconfigurable BLDC motor controller. In this paper, a method for automatic commutation configuration and automatic parameter values detection is presented. The Hall sensors and motor phases configurations are identified. The BLDC motor parameter values are detected automatically using mathematical models. Those parameters include internal resistance, inductance, coefficient of back electromotive force (BEMF), torque coefficient, friction coefficient, and moment of inertia. Experimental results of the automatic commutation configuration and parameter values detection are presented. Those results were used to develop a current controller. Further experimental results indicated that the method could be implemented in a BLDC motor current controller.

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Clustering in block Markov chains

arXiv

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arXiv 2017年

作者： Sanders, Jaron Proutière, Alexandre Yun, Se-Young Kth Royal Institute of Technology School of Electrical Engineering Dept. of Automatic Control Osquldasväg 10 Stockholm10044 Sweden Delft University of Technology Faculty of Electrical Engineering Mathematics and Computer Science Dept. of Quantum and Computer Engineering Mekelweg 4 Delft2628CD Netherlands Korea Advanced Institute of Science and Technology Dept. of Industrial and Systems Engineering 291 Daehak-ro Eoeun-dong Yuseong-gu Korea Republic of

This paper considers cluster detection in Block Markov Chains (BMCs). These Markov chains are characterized by a block structure in their transition matrix. More precisely, the n possible states are divided into a finite number of K groups or clusters, such that states in the same cluster exhibit the same transition rates to other states. One observes a trajectory of the Markov chain, and the objective is to recover, from this observation only, the (initially unknown) clusters. In this paper we devise a clustering procedure that accurately, efficiently, and provably detects the clusters. We first derive a fundamental information-theoretical lower bound on the detection error rate satisfied under any clustering algorithm. This bound identifies the parameters of the BMC, and trajectory lengths, for which it is possible to accurately detect the clusters. We next develop two clustering algorithms that can together accurately recover the cluster structure from the shortest possible trajectories, whenever the parameters allow detection. These algorithms thus reach the fundamental detectability limit, and are optimal in that sense. Copyright © 2017, The Authors. All rights reserved.

关键词： Asymptotic analysis

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