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An intrusion detection approach using improved manifold learning and BVM

International Journal of Advancements in Computing Technology 2012年第11期4卷 148-157页

作者： Li, Yuancheng Li, Pan School of Control and Computer Engineering North China Electric Power University Beijing 102206 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China

Intrusion detection is an important issue in computer network security. It is a classification problem in essence. In this paper, we propose an intrusion detection approach based on improved manifold learning and Ball Vector Machine (BVM). In the first stage, in order to solve the problem of intrusion data's high dimension, we use improved manifold learning approach to play the role of reducing dimensionality of the data that lies on the nonlinear manifold. We propose the improved method called distance-improved manifold learning to compute the distance between points so as to get k nearest neighbors. In the second stage, we use the BVM algorithm to perform the classification procedure, the reduced dimensionality data is used as input of BVM classifier which could differentiate the normal and abnormal actions. We combine the improved manifold learning and BVM to construct an efficient and effective intrusion detection framework. In order to evaluate our approach, we apply it to KDDCUP99 data, experimental results clearly demonstrate that the proposed approach has a good performance in reducing the false positive rate and the detection time while the classification accuracy is basically the same as conventional one class BVM.

关键词： Intrusion detection

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Energy management strategy of islanded microgrid based on power flow control

Energy management strategy of islanded microgrid based on po...

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Innovative Smart Grid Technologies (ISGT)

作者： Ye Zhang Hong Jie Jia Li Guo Key Laboratory of Power System Simulation and Control of Ministry of Education Schoolof Electrical Engineering & Automation Tianjin University Tianjin China Tianjin University Tianjin Tianjin CN

As the remote areas can not be connected to large electric system, using local renewable resources and a certain capacity of energy storage devices to construct a microgrid for power supply will be the only choice. This paper introduces a new energy management strategy of islanded microgrid based on power flow control. The islanded microgrid utilizes the hybrid AC/DC structure. Battery storage system keeps the DC bus voltage constant, PV array as a current source is connected to the DC bus and a main DC/AC inverter in VF mode is used to provide the voltage and frequency references for the AC bus. In this energy management strategy, power flow control is applied to regulate the SOC of batteries in the certain range, control the batteries to avoid over-discharge/over-charge and frequent transition between charge and discharge by the means of output power limitation of the solar energy, switching wind turbine and controllable load and so on. The PSCAD test results show the feasibility and effectiveness of this energy management strategy.

关键词： Batteries Discharges (electric) power generation system-on-a-chip Voltage control Partial discharges Arrays

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Simplified Modeling of DFIG with PWM Nonlinear Characteristics for Fast Transient simulation

Simplified Modeling of DFIG with PWM Nonlinear Characteristi...

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IEEE PES Innovative Smart Grid Technologies Europe

作者： Yin Xu Laijun Chen Ying Chen Zhenquan Sun Department of Electrical Engineering State Key Laboratory of Control and Simulation Tsinghua University Shaanxi Regional Electric Power Group Co. LTD.

ISBN: (纸本)9781467325950

Transient simulation of wind farms provides an effective approach to study dynamic performance of power system with high penetration of wind power. To accelerate the transient simulations, sophisticated modeling methods for the DFIGs are required. In this paper, a general framework is proposed to develop and verify the fast simulation models of the DFIGs, which is based on practical indices designed for evaluation the accuracy and efficiency of the fast simulation. Then, a new model of the DFIG is presented, which can not only describe the nonlinear characteristics of PWM converter but also achieve high computational efficiency at the same time. Test results of a single machine infinity bus system are used to validate the proposed modeling method.

关键词： DFIG Fast simulation Transient simulation model PWM converter Over modulation

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Evolution of the exploding titanium wire in 5-50 kPa ambient gas

Evolution of the exploding titanium wire in 5-50 kPa ambient...

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IEEE International Conference on Plasma Science (ICOPS)

作者： Xiaobing Zou Zhiguo Mao Xinxin Wang Weihua Jiang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Department of Physics and Chemistry College of Physics North China University of Technology Beijing China

Experiments of electrical wire explosions (EEW) for nano-powder production were performed on a small-scale pulsed power device, which consists of a low-inductance capacitor bank of 2-4 μF typically charged to 8-25 kV. Titanium wires, 85 mm in length and 175 μm in diameter, were installed inside a discharge chamber filled with 5-50 kPa air. The peak discharge current is about 8-20kA with a rise time of 6 μs. We investigated the evolution of the exploding titanium wire with a Mach-Zehnder interferometer. From the time sequence of the interferograms, we found that two different modes of wire explosion exist, depending on the ambient gas pressure. As the gas pressure is in the range of 5-20 kPa, more than one vapor burst was observed, which we called multi-burst mode. While the gas pressure is above 40 kPa, the whole wire would explode totally within one single vapor burst, which we called one-burst mode. Based on the calculated deposition energy of the exploding wire and the gas discharge theory, we explained the relationship between the exploding modes and the ambient gas pressure.

关键词： Wires Titanium Educational institutions Discharges (electric) Physics Explosions Electrical engineering

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Positive-sequence component based three-phase unbalanced power flow solution for distribution system with PV nodes

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2012年第1期32卷 115-121页

作者： Li, Hongwei Sun, Hongbin Zhang, An'an Liu, Qingyou State Key Laboratory of Oil and Gas Reservoirs Geology and Exploitation Southwest Petroleum University Chengdu 610500 Sichuan Province China State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

The traditional power flow methods aren't appropriate to the electrical distribution systems with distributed generators (DG). Therefore, a direct unbalanced three-phase power flow algorithm was presented in this paper. The proposed approach which was developed based on the path matrix, utilized the special topological structure of distribution systems and established the incident matrix of node voltages and injection currents. Based on the assumption that the positive-sequence voltage magnitudes of PV nodes are invariable, the relation of reactive power and compensation voltage for the PV nodes had been derived by the positivesequence component and path matrix. As a result, a new approach handling PV nodes of DG had been proposed and could be integrated into the proposed power flow method. It needn't introduce any additional active power at PV nodes and kept the positive-sequence voltage magnitudes on their scheduled values, considering that reactive power limits were not violated. The results of the 6-bus and the 69-bus test systems verified the validity and universality of the proposed methods. © 2012 Chin. Soc. for Elec. Eng.

关键词： Reactive power

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IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL IN GIS

IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL ...

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The ⅪⅩ International Conference on Gas Discharges and Their Applications

作者： DENGWEI DING WENSHENG GAO WEIDONG LIU RUI FENG State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua University

ISBN: (纸本)9771003651221

In order to monitor the on-line condition of GIS and diagnose existing defects,the ultra high frequency(UHF) methods are widely used for detecting partial discharge(PD) owing to its sensitivity and anti-interference *** partial discharge will happen when the electric field is non-uniform because of the defects in *** location of the partial discharge source has an impact on electromagnetic wave generated from the *** the PD detection,the UHF signal acquired by the coupler in GIS is produced by the change in the electric field,so the characteristics of the signal are related with the position of the *** this paper,the distance between the PD source and the inner conductor of GIS is changed;the amplitude of time-domain signal and the frequency spectrum of the UHF signal are *** is discovered that the amplitude of time-domain signal is various with the distance between the defect and the inner conductor,as well as the frequency *** that, the mode of UHF signal in GIS is affected by the location of PD,the component of TEM mode and high order mode(TE mode and TM mode) change with the distance between the PD source and the inner conductor.

关键词： domain IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL IN GIS

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An architecture description language based on dynamic description logics 1

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7th IFIP International Conference on Intelligent Information Processing, IIP 2012

作者： Wang, Zhuxiao Peng, Hui Guo, Jing Zhang, Ying Wu, Kehe Xu, Huan Wang, Xiaofeng School of Control and Computer Engineering State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China Education Technology Center Beijing International Studies University Beijing 100024 China National Computer Network Emergency Response Technical Team/Coordination Center of China Beijing 100029 China Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China

ISBN: (数字)9783642328916

ISBN: (纸本)9783642328909

ADML is an architectural description language based on Dynamic Description Logic for defining and simulating the behavior of system architecture. ADML is being developed as a new formal language and/or conceptual model for representing the architectures of concurrent and distributed systems, both hardware and software. ADML embraces dynamic change as a fundamental consideration, supports a broad class of adaptive changes at the architectural level, and offers a uniform way to represent and reason about both static and dynamic aspects of systems. Because the ADML is based on the Dynamic Description Logic DDL( (D)), which can represent both dynamic semantics and static semantics under a unified logical framework, architectural ontology entailment for the ADML languages can be reduced to knowledge base satisfiability in DDL( (D)), and dynamic description logic algorithms and implementations can be used to provide reasoning services for ADML. In this article, we present the syntax of ADML, explain its underlying semantics using the Dynamic Description Logic DDL( (D)), and describe the core architecture description features of ADML. © 2012 IFIP International Federation for Information Processing.

关键词： Formal languages

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Effects of manganese dioxide additives on the electrical characteristics of Al-doped ZnO varistors

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Science China(Technological Sciences) 2011年第8期54卷 2204-2208页

作者： LONG WangCheng HU Jun HE JinLiang LIU Jun ZENG Rong State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

The effects of manganese dioxide (MnO 2 ) additives on the electrical characteristics of the Al-doped ZnO varistors are investigated. The leakage current densities of the samples decrease first and then increase again with the increase of the amount of MnO 2 additives. Correspondingly, the nonlinear coefficients of the samples keep on increasing and then decrease. In addition, the donor densities increase monotonously with the amount of the doped MnO 2 increasing. The effects of MnO 2 additives on the electrical characteristics of the samples are different from the conclusion of previous literatures. The reasons of the distinct effects are supposed to be related with the donor and interface state densities of the samples.

关键词： ZnO varistots manganese dioxide electrical characteristics low residual voltage ratio simulation

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An Architecture Dynamic Modeling Language for Self-Healing systems

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Procedia Engineering 2012年 29卷 3909-3913页

作者： Zhuxiao Wang Jing Guo Kehe Wu Hui He Fei Chen School of Control and Computer Engineering State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China National Computer Network Emergency Response Technical Team/Coordination Center of China Beijing 100029 China

As modern software-based systems increase in complexity, recovery from malicious attacks and rectification of system faults become more difficult, labor-intensive, and error-prone. These factors have actuated research dealing with the concept of self-healing systems, which employ architectural models to monitor system behavior and use inputs obtaining therefore to adapt themselves to the run-time environment. Numerous architectural description languages (ADLs) have been developed, each providing complementary capabilities for architectural development and analysis. Unfortunately, few ADLs embrace dynamic change as a fundamental consideration and support a broad class of adaptive changes at the architectural level. The Architecture Dynamic Modeling Language (ADML) is being developed as a new formal language and/or conceptual model for representing dynamic software architectures. TheADML couple the static information provided by the system requirements and the dynamic knowledge provided by tactics, and offer a uniform way to represent and reason about both static and dynamic aspects of self-healing systems. Because the ADML is based on the Dynamic Description Logic DDL, architectural ontology entailment for the ADML languages can be reduced to knowledge base satisfiability in DDL.

关键词： Architecture Description Languages Knowledge Representation and Reasoning Software Architecture Dynamic Description Logics Self-Healing systems Dynamic Adaptation

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Substation switching electromagnetic transient analysis using the time domain integral equation with a high order implicit scheme

Substation switching electromagnetic transient analysis usin...

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IEEE International Symposium on Electromagnetic Compatibility (EMC)

作者： Hongjun Xiang Sughun Chang Jun Zou Jians heng Yuan Sergey V. Shenderey State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China Electrical Environment Group Korea Electrotechnology Research Institute Changwon South Korea

A fast electric field integral in time domain using the uneven discretization and the implicit scheme is proposed to calculate the switching electromagnetic transient at a substation. The switching transient currents and the resultant radiated electromagnetic field are calculated. The propose d approach has the strength to model the bus system at a substation with a more complicated and realistic configuration that is difficult to simulate using the circuit-based method, because all the electromagnetic couplings within the bus system are included globally. The proposed method might be one of good candidates to predicate the EMI level at a substation.

关键词： Transient analysis Switches Time domain analysis Wires Integrated circuit modeling Conductors

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