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International Symposium on Advances in Computer and Sensor Networks and systems, 2008

作者： Fei, Yin Dongliang, Zhang Department of Computer Science and Technology Tongji University The Key Laboratory of Embedded System and Service Computing Ministry of Education Shanghai 201804 China

ISBN: (纸本)9781427629807

In this paper, we present the parallel implementation of the traffic microsimulation PMTS (Parallel Microscopic Traffic Simulation) focusing on the performance issues. The parallelization of PMTS is domain decomposition, which means that each processor of the PC cluster is responsible for a different geographical area of the simulation region. We describe the transportation network graph partition and information exchange between domains. We demonstrate the time cost mathematics models for PMTS: the vehicle generation, vehicle position calculation, and vehicle information exchange between domains. The workload balance is obtained by adjusting the boundary lines according to the relative load of adjacent subnetworks. All these works have been proved to be effective when PMTS put into use and the experiment results are also provided which match our analysis.

关键词： Vehicles

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Probabilistic Convergent Hough Transform

Probabilistic Convergent Hough Transform

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International Conference on Information and Automation (ICIA)

作者： Lei Zhu Zhaoqi Chen The Key Laboratory of Embedded System and Service Computing Ministry of Education University of Tongji Shanghai China

To reduce the computational complexity, a novel method of standard Hough transform (SHT), named probabilistic convergent Hough transform (PCHT), is proposed in this paper. PCHT avoids unnecessary cost of SHT in computation by intermittently detecting several points of a line through fast convergence and in memory by using a one-dimensional accumulator. Considering the inevitable error initiated by PCHT, Sensitivity of detection method is introduced to limit the error rate of detecting a fake line within the tolerable range. Experiment is done in various circumstances. Results and comparison between several line detections and PCHT are shown next, and further discussion is given in the final.

关键词： Transforms Noise Convergence Sensitivity Artificial neural networks Probabilistic logic Shape

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Feature selection on chinese text classification using character N-grams

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3rd International Conference on Rough Sets and Knowledge Technology, RSKT 2008

作者： Wei, Zhihua Miao, Duoqian Chauchat, Jean-Hugues Zhong, Caiming Tongji University Key Laboratory Embedded System and Service Computing Ministry of Education Cao'an Road Shanghai 201804 China Laboratoire ERIC Université Lumière Lyon 2 5 avenue Pierre Mendès-France Bron Cedex 69676 France

ISBN: (纸本)3540797203

In this paper, we perform Chinese text classification using n-gram text representation on TanCorp which is a new large corpus special for Chinese text classification more than 14,000 texts divided into 12 classes. We use different n-gram feature (1-, 2-grams or 1-, 2-, 3-grams) to represent documents. Different feature weights (absolute text frequency, relative text frequency, absolute n-gram frequency and relative n-gram frequency) are compared. The sparseness of "document by feature" matrices is analyzed in various cases. We use the C-SVC classifier which is the SVM algorithm designed for the multi-classification task. We perform our experiments in the TANAGRA platform. We found out that the feature selection methods based on n-gram frequency (absolute or relative) always give better results and produce denser matrices. © 2008 Springer-Verlag Berlin Heidelberg.

关键词： Feature Selection

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An Improved Adaptive Exponential Smoothing Model for Short-term Travel Time Forecasting of Urban Arterial Street

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自动化学报 2008年第11期34卷 1404-1409页

作者： LI Zhi-Peng YU Hong LIU Yun-Cai LIU Fu-Qiang Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 200092 P.R. China Intelligent Transportation System Department Shanghai Electrical Apparatus Research Institute Shanghai 200063 P. R. China Institute of Image Processing and Pattern Recognition Shanghai Jiao Tong University Shanghai 200240 P. R. China

旅行时间的短期的预报为聪明的交通系统的成功是必要的。在这份报纸，我们考察预报模型的短期的交通的 state-of-art 并且构画出他们每个模型的基本想法，相关工作，优点和劣势。一改进适应指数的变光滑(IAES ) 模型也被建议克服以前的... 详细信息

旅行时间的短期的预报为聪明的交通系统的成功是必要的。在这份报纸，我们考察预报模型的短期的交通的 state-of-art 并且构画出他们每个模型的基本想法，相关工作，优点和劣势。一改进适应指数的变光滑(IAES ) 模型也被建议克服以前的适应指数的变光滑模型的缺点。然后，比较实验在状况和反常交通调节评估在牌照匹配获得的直接旅行时间数据(每分钟行数) 上预报模型的四个主要分支的性能的正常交通下面被执行。实验的结果证明每个模型似乎有它的自己的力量和软弱。IASE 的预报表演比在更突然预报地平线(预报的和二步) 的另外的模型优异， IASE 能够处理各种交通条件。

关键词：自适应指数平滑模型短期旅行时间预测预测方法信息处理技术城市街道设计方案

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Detecting targets of variable acceleration with High Frequency Surface Wave Radar

Detecting targets of variable acceleration with High Frequen...

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International Radar Symposium (IRS)

作者： Gui renzhou Robert Weigel Key Laboratory of Embedded System and Service Computing Ministry of Education College of Electronics & Information Engineering University of Tongji Shanghai China Institute of Electronic Engineering Friedrich-Alexander-University of Erlangen-Nuremberg Erlangen Germany

ISBN: (纸本)9788372077578

According to the conventional hypothesis, the velocity of target in the coherent integration time (CIT) is invariable in the application of utilizing high frequency surface wave radar to detect target. First, this paper proposes a more proper hypothesis in which the velocity and acceleration of target are treated as time-varying. However the acceleration of target can be regarded as invariable within the small fraction of coherent integration time. Then the model of echo signal in the hypothesis is analyzed. Considering the disadvangtages of some conventional methods of time-frequency analysis such as short-time Fourier transform (STFT) and Wigner-Ville distribution (WVD), the paper proposes the method of time-frequency analysis based on chirplets signal decomposition which can improve the time and frequency resolution simultaneously and solve the cross-term problem in WVD method. Firstly, we process the small fraction of coherent integration time with the chirplets signal decomposition. Then according to the differences between target signal and ocean clutter echo, the BP neural network classifier can be exploited to suppress ocean clutter. The different fractions of coherent integration time are composed together with the method of the nearest correlation. Lastly, the feasibility of the method for detecting targets of variable acceleration is proved by its processing the actual data.

关键词： Time frequency analysis Acceleration Chirp Frequency modulation Oceans Radar Distance measurement

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An Effective and Robust Pedestrians Detecting Algorithm & Symposia

An Effective and Robust Pedestrians Detecting Algorithm & Sy...

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International Conference on Intelligent Transportation

作者： Zhipeng Li Yun Sun Fuqiang Liu Wenhuan Shi Key Laboratory of Embedded System and Service Computing supported by Ministry of Education University of Tongji Shanghai China School of Electronics and Information Engineering University of Tongji Shanghai China Department of Control Science and Technology Shanghai Jiaotong University Shanghai China

In this paper, we present a pedestrian detection approach using spatial histograms of oriented gradients feature. As spatial histograms of oriented gradients consist of marginal distributions of an image over local and global patches, they can preserve shape and contour of a pedestrian simultaneously. There are two main contributions in this paper. First of all, we expand the histograms of oriented gradients features from single-size to variable-size which can capture local and global feature of pedestrian automatically. We call theses feature as the "spatial histograms of oriented gradients". Secondly, we employ histogram similarity and Fisher criterion to measure discriminability of features and select some discriminative features to identify the pedestrian. SVM classifier is constructed to train the selected features from target and surrounding background. The proposed algorithm is tested on some public database. Experimental results show that the proposed approach is efficient and rapid in pedestrian detection.

关键词： Robustness Conferences Histograms Support vector machines Shape Intelligent transportation systems Sun Support vector machine classification Computer vision Image edge detection

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An Improved Adaptive Exponential Smoothing Model for Short-term Travel Time Forecasting of Urban Arterial Street

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Acta Automatica Sinica 2008年第11期34卷 1404-1409页

作者： Zhi-Peng LI Hong YU Yun-Cai LIU Fu-Qiang LIU Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 200092 P. R. China Intelligent Transportation System Department Shanghai Electrical Apparatus Research Institute Shanghai 200063 P. R. China Institute of Image Processing and Pattern Recognition Shanghai Jiao Tong University Shanghai 200240 P. R. China

Short-term forecasting of travel time is essential for the success of intelligent transportation system. In this paper, we review the state-of-art of short-term traffic forecasting models and outline their basic ideas, related works, advantages and disadvantages of each model. An improved adaptive exponential smoothing (IAES) model is also proposed to overcome the drawbacks of the previous adaptive exponential smoothing model. Then, comparing experiments are carried out under normal traffic condition and abnormal traffic condition to evaluate the performance of four main branches of forecasting models on direct travel time data obtained by license plate matching (LPM). The results of experiments show each model seems to have its own strength and weakness. The forecasting performance of IASE is superior to other models in shorter forecasting horizon (one and two step forecasting) and the IASE is capable of dealing with all kind of traffic conditions.

关键词： Travel time short-term forecasting license plate matching (LPM) exponential smoothing

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Research on road topology based mobility prediction schemes

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High Technology Letters 2007年第2期13卷 140-144页

作者：陈林 Chen Hongzhong Jiang Changjun Key Lab of Embedded System and Service Computing of the Ministry of Education Department of Computer Science and Technology Tongji University Shanghai 201804 P.R.China

Geographic routing has been introduced in mobile ad hoc networks and sensor networks. But its per-formance suffers greatly from mobility-induced location errors that can cause Lost Link （LLNK） and LOOP problems. Thus various mobility prediction algorithms have been proposed to mitigate the errors, but sometimes their prediction errors are substantial. A novel mobility prediction technique that incorpo-rates both mobile positioning information and road topology knowledge was presented. Furthermore, the performance of the scheme was evaluated via simulations, along with two other schemes, namely, Linear Velocity Prediction （LVP） and Weighted Velocity Prediction （WVP） for comparison purpose. The results of simulation under Manhattan mobility model show that the proposed scheme could track the movement of a node well and hence provide noticeable improvement over LVP and MVP.

关键词： geographic muting mobility prediction road topology shortest path Manhattan mo-bility model

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WSHLA: Web services-based HLA collaborative simulation framework

WSHLA: Web services-based HLA collaborative simulation frame...

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4th International Conference on Cooperative Design, Visualization, and Engineering, CDVE 2007

作者： Hengye, Zhu Guangyao, Li Lulai, Yuan CAD Research Center Tongji University Shanghai 201804 China Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 201804 China

ISBN: (纸本)9783540747796

Collaborative simulation technology is an important factor in improving the efficiency of complex product design. Although High Level Architecture (HLA)-based simulation technology can meet the needs for simulation in product design, it's also marked by many deficiencies. In this paper, we focus on the introduction of web services into HLA simulation system and propose a Web services-Based HLA Collaborative Simulation Framework (WSHLA). The framework uses web services to encapsulate the invocations of HLA services and then make simulation system more interoperable and reusable. Firstly, the overall structure of WSHLA and the proxy, which acts on behalf of a federate and interacts with Runtime Infrastructure (RTI), are presented. Then, the detailed design and implementation process of WSHLA are discussed. Experimental results show that, using web services, the framework can make up for the deficiencies in HLA simulation system and ensure WSHLA-based collaborative simulation goes smoothly at the expense of some time. © Springer-Verlag Berlin Heidelberg 2007.

关键词： Web services

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An Enhanced Scheduling Solution to Support Quality of service for Broadband Wireless Access Networks

An Enhanced Scheduling Solution to Support Quality of Servic...

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第三届IEEE无线通讯、网络技术暨移动计算国际会议

作者： Fuqiang Liu Yuhui Huang Shangzhi Xu The Key Laboratory of Embedded System and Service Computing supported by Ministry of Education Broadband Wireless Communication and Multimedia Laboratory Tongji University Shanghai China

This paper proposes an enhanced scheduling solution to support different quality of service (QoS) for IEEE 802.16e broadband wireless access network. Based on the existing scheduling algorithm M-LWDF, we do deeper research into how to integrate it into IEEE 802.16e. The proposed scheduling solution combines the key service flow parameters defined by IEEE 802.16e standard with M-LWDF scheme. Simulation results show that the delay character is improved for real-time services using the proposed method.

关键词： scheduling QoS BWA

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