检索结果-内蒙古大学图书馆

Detectable and Undetectable Network Attack Security of Cyber-physical Systems

IFAC-PapersOnLine 2018年第7期51卷 179-185页

作者： Lima, Públio M. Carvalho, Lilian K. Moreira, Marcos V. COPPE Electrical Engineering Program Universidade Federal do Rio de Janeiro Cidade Universitária Ilha do Fundão Rio de JaneiroRJ21.945-970 Brazil

Cyber-physical systems (CPSs) integrate computing and communication capabilities to monitor and control physical processes. In order to do so, communication networks are commonly used to connect sensors, actuators, and controllers, implemented, in general, on programmable Logic Controllers (PLC). The use of communication networks increases the vulnerability of the CPS to attacks that can drive the system to unsafe states. We propose in this paper a defense strategy that prevents damages caused by cyber attacks in the sensor and/or actuator communication channels of supervisory control systems, without changing the behavior of the closed-loop system when it is not attacked. We introduce the definitions of DNA-and UNA-Security, and present necessary and sufficient conditions to verify these properties. © 2018

关键词： Network security Actuators Closed loop control systems Closed loop systems Computation theory Computer crime Control systems Controllers Crime Cyber Physical System Discrete event simulation Embedded systems Process control programmable logic controllers Automata Communication capabilities Cyber physical systems (CPSs) Cyber attacks Monitor and control programmable Logic Controller (PLC) Security Supervisory control systems

来源：评论

学校读者我要写书评

暂无评论

Model Predictive Control of Grid-Connected Voltage-Source Converters Operating as STATCOM with Unbalanced Loads

Model Predictive Control of Grid-Connected Voltage-Source Co...

引用

International Conference on Power Electronics and Drive Systems (PEDS)

作者： Oumar Diene Felipe P. Rocha Claudionor F. Nascimento Edson H. Watanabe COPPE-Electrical Engineering Program Federal University of Rio de Janeiro Cidade Universitaria Rio de Janeiro RJ Brazil Federal University of Sao Carlos Brazil

Power systems are rapidly changing to a new model incorporating a wide amount of distributed generation using renewable sources. In this new scenario grid-connected converters, such as compensators for voltage control like STATCOM, are going to play a critical role in its operation. Voltage-source converters (VSCs) are among the most common topology used in grid-connected converters. The VSCs can be also used for connecting alternative renewable energy source to grid as a distributed generation unit. Basically, a grid-connected VSC is a three-phase three-wire converter in which a capacitor is connected to its dc side, while its ac-side voltage is usually controlled based on a pulse-width modulation (PWM) technique. In this paper, we propose a predictive control method, known as finite set model predictive control (FS-MPC), for the ac-side currents. In this case the VSC is utilized as a STATCOM in which the current is controlled to generate reactive power necessary to adjust the grid voltage. The proposed FS-MPC control strategy is easy to implement and is suited for balanced and unbalanced load conditions. The proposed control system is simulated in a VSC STATCOM configuration by using MATLAB SIMULINK. The results show that the proposed method is suitable STATCOMs operating under unbalanced load conditions.

关键词： Automatic voltage control Power conversion Reactive power Integrated circuits Control systems

来源：评论

学校读者我要写书评

暂无评论

Variations of the doubler of electricity

引用

Physics Education 2019年第3期54卷 035019-035019页

作者： De Queiroz, Antonio C.M. COPPE/EP Electrical Engineering Program Federal University of Rio de Janeiro CP 68504 Rio de Janeiro 21941-972 Brazil

The 'doubler of electricity' is an old static electricity generator, the first using only electrostatic induction and not friction, proposed by Bennet (1787 Phil. Trans. 77 288-96) as a system to amplify small electric charges in order to make them observable in an electroscope. This paper studies the operation of the doubler, and shows that a class of devices working in similar way can be obtained as variations of it and as symmetrical versions. Several new 'doublers' are then described and discussed, including some that multiply by a factor greater than two per cycle. © 2019 IOP Publishing Ltd.

关键词：

来源：评论

学校读者我要写书评

暂无评论

FBG-based sensor applied to volumetric flow rate measurements

FBG-based sensor applied to volumetric flow rate measurement...

引用

SBMO/IEEE MTT-S International Conference on Microwave and Optoelectronics (IMOC)

作者： Alexandre Allil Alex Dante Regina Célia da Silva Barros Allil Cesar Cosenza Carvalho Marcelo Martins Werneck Photonics and Instrumentation Laboratory Electrical Engineering Program Alberto Luiz Coimbra Institute for Graduate Studies and Research in Engineering Federal University of Rio de Janeiro (PEE/COPPE/UFRJ) Rio de Janeiro Brazil

ISBN: (数字)9781728130996

ISBN: (纸本)9781728131009

The primary purpose of an offshore oil production platform flare is to ensure operational safety at the facility by safely disposing the gas whenever needed. This may involve handling of large amounts of gas over a short period of time. It is essential that any measuring equipment, installed in the burner line, does not obstruct the flow of gas, so as not to cause a significant pressure drop. For these types of measurements many sensor technologies are available, however they are all very expensive, in the order of several thousands of dollars. Therefore, this paper presents an optoelectronic sensor solution characterized by its small dimensions, electromagnetic free interference and fast response time, besides its non-flammable property.

关键词： Thermistors Temperature measurement Wind tunnels Temperature sensors Fiber gratings Delay effects Time measurement

来源：评论

学校读者我要写书评

暂无评论

U-Bent POF biosensor coated with gold thin film for E. Coli detection 26

U-Bent POF biosensor coated with gold thin film for E. Coli ...

引用

26th International Conference on Plastic Optical Fibres, POF 2017 - Proceedings

作者： Arcas, A.S. Allil, R.C.S.B. Werneck, M.M. Nanotechnology Program Federal University of Rio de Janeiro COPPE RJ Brazil Electrical Engineering Program Federal University of Rio de Janeiro COPPE RJ Brazil

ISBN: (纸本)9789899734524

Escherichia coli (E. coli) is a bacterial type that inhabits the intestinal tract of humans and animals and its presence in water and food is an indication of fecal contamination. This work presents the development of a fiber-optic sensor coated with gold thin film for E. coli detection as a portable, fast response and low cost alternative to conventional methodologies. The sensor operation is based on intensity modulation excited by a monochromatic light. Bacterial selectivity is guaranteed by anti-E. coli antibody immobilization on the fiber surface. The sensor was able to detect 1.5×103 CFU/mL of bacteria concentration.

关键词： Escherichia coli

来源：评论

学校读者我要写书评

暂无评论

Wind Farm Energy Production Optimization Via Wake Steering

引用

Journal of Physics: Conference Series 2020年第2期1618卷

作者： L A M Lima A K Blatt M N Machuca Voltalia - Rua do Passeio 78 14° andar Centro 20021-290 Rio de Janeiro RJ Brazil Electrical Engineering Program COPPE-UFRJ Cidade Universitaria Centro de Tecnologia bloco H 21941-972 Rio de Janeiro RJ Brazil

The wake steering technique consists in misaligning turbines with respect to the incoming wind with the goal of displacing their wake region and reducing the wake wind speed deficit, thus increasing the power production of other turbines downwind. In this paper, an algorithm is proposed to estimate the amount of production gain a wind farm could achieve by employing this technique. Details about data treatment are provided and an analytical wake model that can represent the wakes displacement is described. A minimization algorithm to calibrate the wake model parameters based on SCADA data is presented, and the complete math needed to solve this problem is developed. Similarly, to find the optimal yaw angle values that maximize the wind farm production, a maximization problem is described along with the full development of the equations behind it. Insights on an efficient computational implementation to solve these problems are shown, based on matrix representation of the described variables. A case study is presented for a small wind farm owned by Voltalia, consisting of five turbines. Results point to an AEP gain in the order of 1%, a relevant value over the course of a project's lifetime.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Wind Turbine Failure Prediction Using SCADA Data

引用

Journal of Physics: Conference Series 2020年第2期1618卷

作者： L A M Lima A Blatt J Fujise Voltalia - Rua do Passeio 78 14° andar Centro 20021-290 Rio de Janeiro RJ Brazil Electrical Engineering Program COPPE-UFRJ Cidade Universitaria Centro de Tecnologia bloco H 21941-972 Rio de Janeiro RJ Brazil

This paper proposes a failure prediction system for wind turbines using the Normal Behavior Model (NBM) approach. By using available SCADA data, the NBMs are trained to make predictions that reflect what would be a turbine's normal operating condition. They are able to identify when a given operating condition is abnormal, which points towards probable component degradation. Alerts are raised based on the daily-averaged prediction error to help the O&M team in identifying turbines that need maintenance. The NBMs are comprised of numerous linear models with different inputs and training sets, according to an ensemble approach that aims to avoid overfitting and to reduce the amount of false-positive predictions. Description and insights on various development steps are presented, such as data treatment, model selection, error calculation and alerts generations. Two test cases are shown using operational data from existing wind turbines, highlighting the system's ability to generate alerts weeks before a severe fault occurs.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Security Against Network Attacks in Supervisory Control Systems

引用

IFAC-PapersOnLine 2017年第1期50卷 12333-12338页

作者： Lima, Públio M. Alves, Marcos V.S. Carvalho, Lilian K. Moreira, Marcos V. COPPE - Electrical Engineering Program Universidade Federal do Rio de Janeiro Cidade Universitária Ilha do Fundão Rio de JaneiroRJ21.945-970 Brazil

Cyber-physical systems (CPSs) integrate computing and communication capabilities to monitor and control physical processes. In order to do so, communication networks are commonly used to connect sensors, actuators, and controllers to monitor and control physical systems. The use of communication networks increases the vulnerability of the CPS to cyber attacks that can drive the system to unsafe states. One of the most powerful cyber attacks is the so-called man-in-the-middle attack, where the intruder can observe, hide, create or replace information in the attacked network channel. We propose in this paper a defense strategy that detects intrusions and prevent damages caused by man-in-the-middle attacks in the sensor and/or control communication channels in supervisory control systems. We also introduce the definition of NA-Safe controllability, and we propose an algorithm to verify this property. © 2017

关键词： Computer crime Control systems Crime Cyber Physical System Discrete event simulation Embedded systems Network security Process control automata Communication capabilities Control communications Cyber physical systems (CPSs) Cyber attacks Man in the middle attacks security Supervisory control systems

来源：评论

学校读者我要写书评

暂无评论

Synchronous Codiagnosability of Modular Discrete-Event Systems

引用

IFAC-PapersOnLine 2017年第1期50卷 6831-6836页

作者： Cabral F.G. Moreira M.V. COPPE Electrical Engineering Program Universidade Federal do Rio de Janeiro Cidade Universitária Ilha do Fundão Rio de Janeiro RJ 21.945-970 Brazil

Automated systems are subject to failures that can alter their expected behavior, leading to a decrease in their performance, and possibly causing equipment damages. In this work, we propose a decentralized synchronized Petri net diagnosis scheme for discrete-event systems modeled as automata. In order to do so, we define the notion of synchronous codiagnosability and propose an algorithm to verify this property. We also discuss the relation between synchronous codiagnosability, synchronous diagnosability and diagnosability of discrete-event systems. © 2017

关键词： automata decentralized failure diagnosis discrete-event systems Failure diagnosis Petri nets

来源：评论

学校读者我要写书评

暂无评论

Fiber-optic sensor for bacteria detection based on intensity-modulated SPR by monochromatic excitation 11

Fiber-optic sensor for bacteria detection based on intensity...

引用

11th Annual TechConnect World Innovation Conference and Expo, Held Jointly with the 20th Annual Nanotech Conference and Expo, and the 2017 National SBIR/STTR Conference

作者： Areas, A.S. Dutra, F.S. Allil, R.C.S.B. Werneck, M.M. Federal University of Rio de Janeiro Nanotechnology Program/COPPE RJ Brazil PETROBRAS Research and Development Center RJ Brazil Institute of Chemical Biological Radiologial and Nuclear Defense Brazilian Army Technological Center Rio de Janeiro Brazil Federal University of Rio de Janeiro Electrical Engineering Program/COPPE RJ Brazil

ISBN: (纸本)9780998878201

This study describes the development of a low cost and ease-to-fabricate sensor for bacteria detection based on intensity-modulated surface plasmon resonance (SPR) by monochromatic excitation in a plastic fiber optic (POF). U-shaped probes with 8-mm bend diameter made of 1 mm poly(methyl methacrylate) POFs were fabricated for SPR sensing. Gold thin films with 30, 50, 70 and 100 nm thickness were deposited on the U-shaped region by RF magnetron sputtering. Anti-E. coli antibodies were immobilizated on the surface of gold deposited over the fiber. Tests with E. coli demonstrated a detection limit of 104 UFC/mL.

关键词： Plastic optical fibers

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：