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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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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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Bird's Eye View on Systems and control - General View and Case Studies

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IFAC-PapersOnLine 2016年第6期49卷 274-279页

作者： Vámos, T. Bars, R. Sik, D. Institute of Computer Science and Control Hungarian Academy of Sciences MTA-SZTAKI Budapest Hungary Dept. of Automation and Applied Informatics Budapest University of Technology and Economics MTA-BME Control Engineering Research Group Budapest Hungary

Systems and control are all around us. System view, understanding systems and how they are controlled is important for everyone. The behavior of systems is determined by some fundamental principles which can be understood by everyone. The main principles governing systems and control are presented on different levels. The first level is dedicated for everyone. Comics-like interpretation is provided with explanations. The second level discusses the main topics dedicated for the interested students. Several case studies demonstrate how system view is considered in different areas of life. With this approach systems in different areas of life could be better understood contributing to better decisions influencing their performance. The third level provides deeper insight into some aspects of modern mathematical system theory, to geometric view of control systems. The material is available on a website on the internet. © 2016

关键词： control theory Algorithms Case studies control disciplines control education control structure Systems and control

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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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Multiagent coverage problems: The trade-off between anarchy and stability

arXiv

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arXiv 2017年

作者： Ramaswamy, Vinod Paccagnan, Dario Marden, Jason R. Dept. of Electrical Computer and Energy Engineering University of Colorado BoulderCO80309 United States Automatic Control Laboratory ETH Zürich Zurich Switzerland Electrical and Computer Engineering Department UC Santa Barbara Santa BarbaraCA93106 United States

Networked systems are ubiquitous in today's world with examples spanning from ecology to the social and engineering sciences. Much of the research in networked systems is analytical, where the focus is on characterizing (and potentially inuencing) the emergent collective behavior, e.g., predicting the distribution of animals and humans in a given ecological system. A more recent trend of research focuses on the design of networked systems capable of achieving diverse and highly coordinated collective behavior in the absence of centralized control, e.g., designing a team of unmanned aerial vehicles to monitor the perimeter of a wild fire. Unfortunately, our understanding of how microscopic behavior impacts the macroscopic phenomena in network systems is inadequate for meeting the demands of this emerging design task. This paper focuses on an instance of this design task for a well-studied class of coverage problems where the goal is to allocate a collection of agents to a subset of resources in order to maximize the cumulative value of the covered resources. Our first result demonstrates that any agent-based algorithm relying solely on local information induces a fundamental trade-off between the best and worst case performance guarantees, as measured by the price of anarchy and price of stability. This result highlights how the information available to the agents translates to constraints on the achievable efficiency guarantees in networked control systems. Our second results demonstrates how to use an additional piece of system-level information to breach these limitations, thereby improving the system's performance. Copyright © 2017, The Authors. All rights reserved.

关键词： Networked control systems

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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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An analysis on the reliability of a series of texture and shape descriptors for melanoma diagnosis

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2 2期78 78卷 23-34页

作者： Udrea, Andreea Popescu, Dumitru Miron, Cristian Dept. of Automatic Control and Systems Engineering University Politehnica of Bucharest Romania

Early detection of melanoma can substantially reduce the mortality rate associated to this aggressive type of skin cancer. In this paper, a series of second order statistics texture descriptors are investigated for relevance in (normalised) RGB, HSV, YCrCb CIEXYZ and CIELab color spaces, along with a series of shape features. The best results are obtained for the following shape descriptors: contour asymmetry index, circularity index and mass-radius fractal dimension and for the following texture descriptors: uniformity for the RGB channels. These can be used along with other skin lesions descriptors for a high accuracy automated classification algorithm for melanoma early detection.

关键词： Fractal dimension

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