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International Conference on Control, Automation, Robotics and Vision

作者： Fanghong Guo Changyun Wen Jiawei Chen Energy Research Institute at NTU (ERI@N) Interdisciplinary Graduate School Nanyang Technological University Singapore School of Electrical and Electronic Engineering Nanyang Technological University Singapore Key Laboratory of Dependable Service Computing in Cyber Physical Society of the Ministry of Education and School of Automation Chongqin University China

ISBN: (纸本)9781509035502

This paper presents a distributed voltage unbalance compensation method for an islanded microgrid (MG) system. By using hierarchical control concept, we design a distributed compensation scheme in the secondary control layer, while the traditional inverter control methods including voltage and current PR control, droop control, virtual impedance are implemented in the primary layer. Different from most existing centralized compensation methods, no specified individual centralized secondary controller exists. We decompose the traditional centralized controller into several local secondary controllers. A novel distributed PI controller with negative sequence current feedback is designed in each secondary controller. By allowing them to exchange information with their neighboring controllers respectively, the unbalanced voltage in the sensitive load bus (SLB) can be compensated by all the distributed generators (DGs) cooperatively. In addition, the compensation effort of each DG is designed to be proportional to their power ratings respectively. An islanded microgrid system consisting of 4 DGs is built in MATLAB to validate the proposed method.

关键词： Voltage control Inverters Microgrids Electronic mail Generators Reactive power Automation

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Predicting student performances from access records on general websites

Predicting student performances from access records on gener...

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作者： Zhou, Qing Mou, Chao Zheng, Youjie Meng, Yao ChongQing University ChongQing China Key Laboratory of Dependable Service Computing in Cyber Physical Society of Ministry of Education College of Computer Science Chong Qing University ChongQing China

ISBN: (纸本)9781138028302

Predicting student performance using data mining tools is a difficult yet worthwhile undertaking for educational institutions. Previous studies on the student performance prediction restricted the data sources to one specific learning system. We show that it is possible to predict whether a student can pass Data Structure course from his or her access records on general websites. We first created a domain names catalog by assigning more than 12,000 domain names to 335 subcategories, 80 main categories and five top categories. This catalog was later used to calculate the frequencies that each student visited different categories of websites from about 20 million Internet access records. We then selected 14 categories of domain names as features to train a Naive Bayes Classifier. Experiments show that our method achieves a sensitivity (true positive rate) of nearly 90% and a specificity (true negative rate) of above 60%. Moreover, the proposed model has a high interpretability and conforms to our teaching experience. © 2015 Taylor & Francis Group, London.

关键词： Websites

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Laplacian Scale-Space Behavior of Planar Curve Corners

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IEEE Transactions on Pattern Analysis and Machine Intelligence 2015年第11期37卷 2207-2217页

作者： Zhang, Xiaohong Qu, Ying Yang, Dan Wang, Hongxing Kymer, Jeff Key Laboratory of Dependable Service Computing Cyber Physical Society Ministry of Education Chongqing400044 China School of Software Engineering Chongqing University Chongqing401331 China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing400044 China College of Computer Science Chongqing University Chongqing400044 China

Scale-space behavior of corners is important for developing an efficient corner detection algorithm. In this paper, we analyze the scale-space behavior with the Laplacian of Gaussian (LoG) operator on a planar curve which constructs Laplacian Scale Space (LSS). The analytical expression of a Laplacian Scale-Space map (LSS map) is obtained, demonstrating the Laplacian Scale-Space behavior of the planar curve corners, based on a newly defined unified corner model. With this formula, some Laplacian Scale-Space behavior is summarized. Although LSS demonstrates some similarities to Curvature Scale Space (CSS), there are still some differences. First, no new extreme points are generated in the LSS. Second, the behavior of different cases of a corner model is consistent and simple. This makes it easy to trace the corner in a scale space. At last, the behavior of LSS is verified in an experiment on a digital curve. © 2015 IEEE.

关键词： Laplace transforms

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应用EMA/EC双探头在无损评估中的仿真和实验研究

应用EMA/EC双探头在无损评估中的仿真和实验研究

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2016远东无损检测新技术论坛

作者： Niu Zhi OUYANG Qi Shen Zhixi Zhang Xinlan Zhang Tianfeng The Key Laboratory of Dependable Service Computing in Cyber Physical Society of Ministry of Educatio College of Computer Science and Engineering Chongqing University of Technology Chongqing 400054

在无损评估中,应用电磁超声/电涡流(EMAT/EC)双探头对检测表面缺陷和内部缺陷有很大的优势。通过有限元的方法对EMA/EC融合检测的原理进行仿真。针对EC,通过理论和实验的方法,研究了涡流场的涡流分布,目的是研究由涡流场引起的线圈阻抗... 详细信息

在无损评估中,应用电磁超声/电涡流(EMAT/EC)双探头对检测表面缺陷和内部缺陷有很大的优势。通过有限元的方法对EMA/EC融合检测的原理进行仿真。针对EC,通过理论和实验的方法,研究了涡流场的涡流分布,目的是研究由涡流场引起的线圈阻抗变化的问题。针对EMAT,使用多场Comsol仿真软件,对EMAT线圈激励的超声波的传播特性进行分析。仿真和实验的结果表明,在无损检测中,使用EMA/EC复合的检测方法,能有效地检测出表面缺陷和内部缺陷。

关键词：电磁超声电涡流传感器融合无损测试和评估

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Design of persistent embedded main memory databases on non-volatile memory

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Ruan Jian Xue Bao/Journal of Software 2016年 27卷 320-327页

作者： Sha, Edwin H.-M Chen, Xian-Zhang Ma, Dian-Long Zhuge, Qing-Feng College of Computer Science Chongqing University Chongqing400044 China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing University Chongqing400044 China

With the increasing complication and variation of embedded applications in recent decades, both industry and academia have been proposing to use main memory databases to meet the ever-growing demand of high-performance data processing in embedded systems. Nevertheless, the existing main memory databases all rely on the secondary storage, such as magnetic disks and SSD, to maintain the real database persistently. Moreover, they have large overhead in synchronizing the data between memory and storage via slow I/O operations. Even though they are deployed in the emerging Non-Volatile Memory (NVM), the existing main memory databases are unable to get rid of disks for their temporary in-memory data structures cannot survive system reboot. In solving the persistency problem of main memory databases, this paper proposes to manage the NVM by the database itself that is independent from the memory management system. The information of NVM and the metadata of the database are persistently fixed on the NVM. The proposed ideas are implemented in an open-sourced main memory database, Redis. The experimental results show that compared with the existing persistency scheme of Redis AOF, the proposed approach improves the speeds of starting database, closing database, set operations, and delete operations by 2400 times, 5 times, 58 times, and 34 times, respectively. © Copyright 2016, Institute of Software, the Chinese Academy of Sciences. All rights reserved.

关键词： Embedded systems

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Fitting Skeletal Object Models Using Spherical Harmonics Based Template Warping

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IEEE Signal Processing Letters 2015年第12期22卷 2269-2273页

作者： Tu, Liyun Yang, Dan Vicory, Jared Zhang, Xiaohong Pizer, Stephen M. Styner, Martin College of Computer Science Chongqing University Chongqing400044 China Department of Computer Science University of North Carolina Chapel HillNC27599 United States School of Software Engineering Chongqing University Chongqing400044 China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing400044 China

We present a scheme that propagates a reference skeletal model (s-rep) into a particular case of an object, thereby propagating the initial shape-related layout of the skeleton-to-boundary vectors, called spokes. The scheme represents the surfaces of the template as well as the target objects by spherical harmonics and computes a warp between these via a thin plate spline. To form the propagated s-rep, it applies the warp to the spokes of the template s-rep and then statistically refines. This automatic approach promises to make s-rep fitting robust for complicated objects, which allows s-rep based statistics to be available to all. The improvement in fitting and statistics is significant compared with the previous methods and in statistics compared with a state-of-the-art boundary based method. © 2015 IEEE.

关键词： Medical imaging

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A Generic Feedback System for Better Evaluation of Teacher Performance

A Generic Feedback System for Better Evaluation of Teacher P...

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2015 6th IEEE International Conference on Software Engineering and service Science(ICSESS 2015)

作者： Hamad Naeem Jun Sang Waqar Ali Abro Muhammad Rashid Naeem Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education School of Software Engineering Chongqing University

in existing educational environment, teacher’s performance is playing vital role in growth of students as well as institution. The quality of Instruction is basic constituent for successful learning. For better collaboration between students and teachers, it has become mandatory to introduce comprehensive performance evaluation mechanism. In modern age, information technology provides us optimal solution to evaluate teacher’s performance. In this paper, we proposed a generic feedback model using unified modeling language(UML). This model can be easily implemented in any institutional environment due to its non specific behavior. This model predicts better results of teacher’s performance using methods of data mining tool. In the conclusion, we compared results of various data mining techniques and also suggesting an appropriate method for this system.

关键词： Data mining Feedback System Performance analysis UML

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Online fraud detection model based on social network analysis

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Journal of Information and Computational Science 2015年第7期12卷 2553-2562页

作者： Wang, Peng Li, Ji Ji, Bigui College of Computer Science Chongqing University Chongqing China Key Laboratory for Dependable Service Computing in Cyber Physics Society Ministry of Education Chongqing China

With the rapid development of the Internet, the way of our living and thinking has changed. Because of the anonymity and low-cost legal sanctions, e-commerce has been booming on the Internet. Unfortunately, rapid commercial success has made e-commerce sites a lucrative medium for committing fraud. Therefore, we proposed a method that used for fraud detection and prevention on platform. First, we implemented a parallel web crawling agent to collect real users and transaction data. Second, we proposed Reverse Graph and Common Trade Cumulative Graph (CTCG) theory to extract features of common transaction. Third, we extracted the features of graph-level based on the Page-Rank and K-core clustering algorithm and replaced the PageRank values with reasonable TrustRank values, added BadRank values for identifying potential fraud users. Finally, we conducted a series of experiments using the Random Forest and verified the performance of our method by applying it to real transaction cases. In summary, our proposed model is effective in identifying potential fraudulent users on the fraud platform. Copyright © 2015 Binary Information Press.

关键词： Decision trees

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Impulsive stabilization of a class of nonlinear system with bounded gain error

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Chinese Physics B 2014年第12期23卷 103-108页

作者：马铁东赵飞亚 Key Laboratory of Dependable Service Computing in Cyber Physical Society of Ministry of Education Chongqing University College of Automation Chongqing University

Considering mechanical limitation or device restriction in practical application, this paper investigates impulsive stabilization of nonlinear systems with impulsive gain error. Compared with the existing impulsive analytical approaches,the proposed impulsive control method is more practically applicable, which includes control gain error with an acceptable boundary. A sufficient criterion for global exponential stability of an impulsive control system is derived, which relaxes the condition for precise impulsive gain efficiently. The effectiveness of the proposed method is confirmed by theoretical analysis and numerical simulation based on Chua＇s circuit.

关键词： bounded gain error impulsive control exponential stability Chua＇s circuit

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Fuzzy Risk Decision of Route Switching for Intelligent Logistics

Fuzzy Risk Decision of Route Switching for Intelligent Logis...

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The 2nd National Conference on Information Technology and Computer Science(CITCS 2015)

作者： Senlin CHENG Buqing LIU Hu XU Chuan WANG College of Automation Chongqing University Key Laboratory of Dependable Service Computing in Cyber Physical Society (Chongqing University) Ministry of Education

To reduce the cost in transportation for intelligent logistics,the paper focused on the route-switching decision for trucks. In the paper, by means of risk evaluation based on fuzzy set theory, the risk factors in intelligent logistics was analyzed, the anatomy of key factors was made, and a simple application case of risk decision was given. The application case demonstrated its rationality and feasibility. The research shows that a reasonable driving route can be selected using fuzzy risk decision.

关键词： Intelligent Logistics Route Selection Fuzzy Risk Decision

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