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Fine-grained P2P traffic classification by simply counting flows

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Frontiers of Information Technology & Electronic Engineering 2015年第5期16卷 391-403页

作者： Jie HE Yue-xiang YANG Yong QIAO Wen-ping DENG College of Computer National University of Defense Technology The research Institution China Electronic Equipment & System Engineering Company

The continuous emerging of peer-to-peer(P2P) applications enriches resource sharing by networks, but it also brings about many challenges to network management. Therefore, P2 P applications monitoring, in particular,P2 P traffic classification, is becoming increasingly important. In this paper, we propose a novel approach for accurate P2 P traffic classification at a fine-grained level. Our approach relies only on counting some special flows that are appearing frequently and steadily in the traffic generated by specific P2 P applications. In contrast to existing methods, the main contribution of our approach can be summarized as the following two aspects. Firstly, it can achieve a high classification accuracy by exploiting only several generic properties of flows rather than complicated features and sophisticated techniques. Secondly, it can work well even if the classification target is running with other high bandwidth-consuming applications, outperforming most existing host-based approaches, which are incapable of dealing with this situation. We evaluated the performance of our approach on a real-world trace. Experimental results show that P2 P applications can be classified with a true positive rate higher than 97.22% and a false positive rate lower than 2.78%.

关键词： Traffic classification Peer-to-peer(P2P) Fine-grained Host-based

Space Charge Transient Kinetic Characteristics in DC Air Corona Discharge at Atmospheric Pressure

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Plasma Science and Technology 2014年第8期16卷 749-757页

作者：刘兴华咸日常孙学峰王涛吕学宾陈素红杨帆 State Grid Zibo Power Supply company State Grid Shandong Electric Power company State Grid Shandong Electric Power research Institute State Key Laboratory of Power Transmission Equipment & system Security and New Technology Chongqing University

Investigating the corona mechanism plays a key role in enhancing the performance of electrical insulation systems. Numerical simulation offers a better understanding of the physical characteristics of air corona discharges. Using a two-dimensional axisymmetrical kinetics model, into which the photoionization effect is incorporated, the DC air corona discharge at atmosphere pressure is studied. The plasma model is based on a self-consistent, multi-component, and con- tinuum description of the air discharge, which is comprised of 12 species and 22 reactions. The discharge voltage-current characteristic predicted by the model is found to be in quite good agree- ment with experimental measurements. The behavior of the electronic avalanche progress is Mso described. 0＋ and N＋ are the dominant positive ions, and the values of 0- and 02 densities are much smaller than that of the electron. The electron and positive ion have a low-density thin layer near the anode, which is a result of the surface reaction and absorption effect of the electrode. As time progresses, the electric field increases and extends along the cathode surface, whereas the cathode fall shrinks after the corona discharge hits the cathode; thus, in the cathode sheath, the electron temperature increases and the position of its peak approaches to the cathode. The present computational model contributes to the understanding of this physical mechanism, and suggests ways to improve the electrical insulation system.

关键词： air corona discharge atmospheric pressure numerical simulation mechanism

A novel capacitive micro-accelerometer with grid strip capacitances and sensing gap alterable capacitances

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Journal of Semiconductors 2009年第3期30卷 72-77页

作者：董林玺陈金丹颜海霞霍卫红李永杰孙玲玲 Key Laboratory of RF Circuits and system of the Ministry of Education Hangzhou Dianzi University Toshiba Hydro-Electro Equipments company

The comb capacitances fabricated by deep reactive ion etching （RIE） process have high aspect ratio which is usually smaller than 30 ： 1 for the complicated process factors, and the combs are usually not parallel due to the well-known micro-loading effect and other process factors, which restricts the increase of the seismic mass by increasing the thickness of comb to reduce the thermal mechanical noise and the decrease of the gap of the comb capacitances for increasing the sensitive capacitance to reduce the electrical noise. Aiming at the disadvantage of the deep RIE, a novel capacitive micro-accelerometer with grid strip capacitances and sensing gap alterable capacitances is developed. One part of sensing of inertial signal of the micro-accelerometer is by the grid strip capacitances whose overlapping area is variable and which do not have the non-parallel plate＇s effect caused by the deep RIE process. Another part is by the sensing gap alterable capacitances whose gap between combs can be reduced by the actuators. The designed initial gap of the alterable comb capacitances is relatively large to depress the effect of the maximum aspect ratio （30 ： 1） of deep RIE process. The initial gap of the capacitance of the actuator is smaller than the one of the comb capacitances. The difference between the two gaps is the initial gap of the sensitive capacitor. The designed structure depresses greatly the requirement of deep RIE process. The effects of non-parallel combs on the accelerometer are also analyzed. The characteristics of the micro-accelerometer are discussed by field emission microscopy （FEM） tool ANSYS. The tested devices based on slide-film damping effect are fabricated, and the tested quality factor is 514, which shows that grid strip capacitance design can partly improve the resolution and also prove the feasibility of the designed silicon-glass anodically bonding process.

关键词： capacitive accelerometer inertial sensor high precision deep RIE

Novel Door-opening Method for Six-legged Robots Based on Only Force Sensing

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Chinese Journal of Mechanical Engineering 2017年第5期30卷 1227-1238页

作者： Zhi-Jun Chen Feng Gao Yang Pan State Key Laboratory of Mechanical system and Vibration Shanghai Jiao Tong University Shanghai GQY Robot Limited company

Current door-opening methods are mainly developed on tracked, wheeled and biped robots by applying multi-DOF manipulators and vision systems. However, door-opening methods for six-legged robots are seldom studied, especially using 0-DOF tools to operate and only force sensing to detect. A novel door-opening method for six-legged robots is developed and imple- mented to the six-parallel-legged robot. The kinematic model of the six-parallel-legged robot is established and the model of measuring the positional relationship between the robot and the door is proposed. The measurement model is completely based on only force sensing. The real- time trajectory planning method and the control strategy are designed. The trajectory planning method allows the maximum angle between the sagittal axis of the robot body and the normal line of the door plane to be 45°. A 0-DOF tool mounted to the robot body is applied to operate. By integrating with the body, the tool has 6 DOFs and enough workspace to operate. The loose grasp achieved by the tool helps release the inner force in the tool. Experiments are carried out to validate the method. The results show that the method is effective and robust in opening doors wider than 1 m. This paper proposes a novel door-opening method for six-legged robots, which notably uses a O-DOF tool and only force sensing to detect and open the door.

关键词： Door-opening·Six-legged robots· Forcesensing · O-DOF tool

A digital prediction algorithm for a single-phase boost PFC

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Journal of Semiconductors 2012年第12期33卷 86-92页

作者：王青陈宁孙伟锋陆生礼时龙兴 National ASIC system Engineering research Center Southeast University

A novel digital control algorithm for digital control power factor correction is presented, which is called the prediction algorithm and has a feature of a higher PF （power factor） with lower total harmonic distortion, and a faster dynamic response with the change of the input voltage or load current. For a certain system, based on the current system state parameters, the prediction algorithm can estimate the track of the output voltage and the inductor current at the next switching cycle and get a set of optimized control sequences to perfectly track the trajectory of input voltage. The proposed prediction algorithm is verified at different conditions, and computer simulation and experimental results under multi-situations confirm the effectiveness of the prediction algorithm. Under the circumstances that the input voltage is in the range of 90-265 V and the load current in the range of 20%-100%, the PF value is larger than 0.998. The 0.02 s without overshoot. The experimental results startup and the recovery times respectively are about 0.1 s and also verify the validity of the proposed method.

关键词： PFC digital control prediction transient performance

Influence of fin architectures on linearity characteristics of AlGaN/GaNFinFETs

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Chinese Physics B 2018年第4期27卷 432-436页

作者： Ting-Ting Liu Kai Zhang Guang-Run Zhu Jian-Jun Zhou Yue-Chan Kong Xin-Xin Yu Tang-Sheng Chen research Institution China Electronic Equipment ＆ System Engineering Company Beijing 100039 China Science and Technology on Monolithic Integrated Circuits and Modules Laboratory Nanjing Electronic Devices Institute Nanjing 210016 China

We investigate the influence of fin architecture on linearity characteristics of AlGaN/*** is found that the Fin FET with scaled fin dimensions exhibits much flatter Gm characteristics than the one with long fins as well as planar *** to the comparative study,we provide direct proof that source resistance rather than tri-gate structure itself dominates the Gm ***,power measurements show that the optimized FinFET is capable of delivering a much higher output power density along with significant improvement in linearity characteristics than conventional planar *** study also highlights the importance of fin design in GaN-based FinFET for microwave power application,especially high-linearity applications.

关键词： AlGaN/GaNFinFETs output power density linearity characteristics

Scenario-based analysis and probability assessment of sub-synchronous oscillation caused by wind farms with direct-driven wind generators

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Journal of Modern Power systems and Clean Energy 2019年第2期7卷 243-253页

作者： Zhi AN Chen SHEN Zetian ZHENG Feng LIU Xiaoqing CHANG Wei WEI Department of Electrical Engineering Tsinghua UniversityBeijingChina China State Key Laboratory of Power system and Generation Equipment BeijingChina Electric Power research Institute of Sichuan Electric Power company ChengduChina

Recently, explanations of the sub-synchronous oscillation(SSO) caused by wind farms based on directdriven wind generators(DDWGs) have been published in the literatures, in which the controller parameters of DDWGs and the system equivalent parameters play an important role. However, more than one set of parameters can cause weakly damped sub-synchronous modes. The most vulnerable and highly possible scenario is still unknown. To find scenarios that have potential oscillation risks, this paper proposes a small disturbance model of wind farms with DDWGs connected to the grid using a state-space modeling technique. Taguchi’s orthogonal array testing is introduced to generate different *** scenarios with different parameter settings that may lead to SSOs are found. A probabilistic analysis method based on the Gaussian mixture model is employed to evaluate the consistency of these scenarios with the actual accidents. Electromagnetic transient simulations are performed to verify the findings.

关键词： Direct-driven wind generator Subsynchronous oscillation Probabilistic assessment Randomness

Design and construction of super-long span bridges in China: Review and future perspectives

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Frontiers of Structural and Civil Engineering 2020年第4期14卷 803-838页

作者： Wei HUANG Minshan PET Xiaodong LIU Ya WEI Intelligent Transportation system research Center Southeast UniversityNanjing 211189China China Communications Construction company Ltd. Beijing 100088China Department of Civil Engineering Tsinghua UniversiyBeijing 100084China

Super-long span bridges demand high design requirements and involve many difficulties when constructed,which is an important indicator to reflect the bridge technical level of a *** the past three decades,a large percentage of the new long-span bridges around the world were built in China,and thus,abundant technological innovations and experience have been accumulated during the design and *** paper aims to review and summarize the design and construction practices of the superstructure,the substructure,and the steel deck paving of the long-span bridges during the past decades as well as the current operation status of the existing long-span bridges in China.A future perspective was given on the developing trend of high-speed railway bridge,bridge over deep-sea,health monitoring and maintenance,intellectualization,standard system,and information technology,which is expected to guide the development direction for the construction of future super long-span bridges and promote China to become a strong bridge construction country.

关键词： long-span bridges steel box girder design technology construction technology,review and future perspectives

Asking one mechanism in glial cells during neuroinflammation

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Neural Regeneration research 2025年第4期20卷 1077-1078页

作者： Xiaoli Guo Chikako Harada Takayuki Harada Visual research Project Tokyo Metropolitan Institute of Medical ScienceTokyoJapan

Multiple sclerosis(MS),which is characterized by inflammatory demyelination in the central nervous system(CNS),is the most common neurological disease in the young adult *** autoimmune encephalomyelitis(EAE),an animal model of MS,is often used in preclinical *** data indicate that in addition to immune cells such as T cells and dendritic cells,CNS resident microglia and astrocytes play important roles in demyelinating neuroinflammation(Healy et al.,2022).In particular,microglia are key immune-competent cells that can respond to environmental *** depletion of transforming growth factor-β-activated kinase 1,a mitogen-associated protein kinase kinase kinase,in microglia is reported to reduce CNS inflammation and diminish axonal and myelin damage *** suggests that elucidating the mechanisms of microglia-specific responses during pathologies may help in the development of treatments that reduce EAE/MS disease severity(Goldmann et al.,2013).

关键词： inflammation clinical