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Time-Ordered Collaborative Filtering for News Recommendation

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China Communications 2015年第12期12卷 53-62页

作者： XIAO Yingyuan AI Pengqiang Ching-Hsien Hsu WANG Hongya JIAO Xu tianjin University of technology tianjin key lab of Intelligence computing and novel software technology Chung Hua University Donghua University

Faced with hundreds of thousands of news articles in the news websites,it is difficult for users to find the news articles they are interested ***,various news recommender systems were *** the news recommendation,these news articles read by a user is typically in the form of a time ***,traditional news recommendation algorithms rarely consider the time sequence characteristic of user browsing ***,the performance of traditional news recommendation algorithms is not good enough in predicting the next news article which a user will *** solve this problem,this paper proposes a time-ordered collaborative filtering recommendation algorithm(TOCF),which takes the time sequence characteristic of user behaviors into ***,a new method to compute the similarity among different users,named time-dependent similarity,is *** demonstrate the efficiency of our solution,extensive experiments are conducted along with detailed performance analysis.

关键词： similarity collaborative compute recommendation filtering users hundreds Collaborative Recommendation interested

Study on the classification of multi-spectral images based on a FSVM multi-class classifier with the binary tree

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Optoelectronics Letters 2010年第1期6卷 61-64页

作者：王怀彬马京华王春东 tianjin key laboratory of intelligent computing and novel software technology and key laboratory of Computer Visionand System Ministry of EducationTianjin University of Technology

Due to the features of the multi-spectral images, the result with the usual methods based on the support vector machine (SVM) and binary tree is not satisfactory. In this paper, a fuzzy SVM multi-class classifier with the binary tree is proposed for the classification of multi-spectral images. The experiment is conducted on a multi-spectral image with 6 bands which contains three classes of terrains. The experimental results show that this method can improve the segmentation accuracy.

关键词：模糊支持向量机多光谱图像树分类器常用方法二叉树 SVM 实验分割

A method for brain 3D surface reconstruction from MR images

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Optoelectronics Letters 2014年第5期10卷 383-386页

作者：赵德新 tianjin key laboratory of intelligent computing and novel software technology Key Laboratory of Computer Vision and SystemMinistry of EducationTianjin University of Technology

Due to the encephalic tissues are highly irregular, three-dimensional （3D） modeling of brain always leads to compli- cated computing. In this paper, we explore an efficient method for brain surface reconstruction from magnetic reso- nance （MR） images of head, which is helpful to surgery planning and tumor localization. A heuristic algorithm is pro- posed foi＂ surface triangle mesh generation with preserved features, and the diagonal length is regarded as the heuristic information to optimize the shape of triangle. The experimental results show that our approach not only reduces the computational complexity, but also completes 3D visualization with good quality.

关键词： Heuristic algorithms Magnetic resonance imaging Mesh generation Surface reconstruction Three dimensional computer graphics

MR image denoising method for brain surface 3D modeling

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Optoelectronics Letters 2014年第6期10卷 477-480页

作者：赵德新刘朋杰张德干 tianjin key laboratory of intelligent computing & novel software technology Key Laboratory of Computer Vision and System Ministry of Education Tianjin University of Technology

Three-dimensional(3D) modeling of medical images is a critical part of surgical simulation. In this paper, we focus on the magnetic resonance(MR) images denoising for brain modeling reconstruction, and exploit a practical solution. We attempt to remove the noise existing in the MR imaging signal and preserve the image characteristics. A wavelet-based adaptive curve shrinkage function is presented in spherical coordinates system. The comparative experiments show that the denoising method can preserve better image details and enhance the coefficients of contours. Using these denoised images, the brain 3D visualization is given through surface triangle mesh model, which demonstrates the effectiveness of the proposed method.

关键词： Magnetic resonance Magnetic resonance imaging Medical imaging Three dimensional computer graphics Wavelet analysis

Performance of CO-OFDM system with RS-Turbo concatenated code

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Optoelectronics Letters 2015年第6期11卷 457-460页

作者：童峥嵘胡桂彬曹晔张卫华 key laboratory of Film Electronics and Communication Devices and key laboratory of intelligent computing and novel software technology Tianjin University of Technology

In this paper,the RS-Turbo concatenated code is applied to coherent optical orthogonal frequency division multiplexing(CO-OFDM) ***(186,166,8) and Turbo code with code rate of 1/2 are employed for RS-Turbo concatenated *** decoding algorithms,which are Max-Log-MAP algorithm and Log-MAP algorithm,are adopted for Turbo decoding,and the iteration Berlekamp-Massey(BM) algorithm is adopted for RS *** simulation results show that the bit error rate(BER) performance of CO-OFDM system with RS-Turbo concatenated code is significantly improved at high optical signal to noise ratio(OSNR),and the iteration number is reduced compared with that of the Turbo coded ***,when the Max-Log-MAP algorithm is adopted for Turbo decoding,the transmission distance of CO-OFDM system with RS-Turbo concatenated code can reach about 400 km without error,while that of the Turbo coded system can only reach about 240 km when BER is lower than 10^(-4) order of magnitude.

关键词： OFDM系统 RS解码 Max-Log-MAP算法性能 Turbo码正交频分复用解码算法光信噪比

Research on the transmission performance of turbo codes in DDO-OFDM system

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Optoelectronics Letters 2015年第2期11卷 134-136页

A direct detection optical orthogonal frequency division multiplexing(DDO-OFDM)system using turbo codes is built,and the transmission performance comparison between coded system and uncoded system is *** decoding algorithms,which are Log-maximum a posteriori(MAP),Max-Log-MAP and threshold Max-Log-MAP,are used in the turbo coded *** comparing three decoding algorithms,the system using Max-Log-MAP algorithm has the best bit error rate(BER)*** the transmission distance of 240 km,the uncoded system with transmission rate of 30 Gbit/s can get the BER performance at the degree of 8.93×10-3 with optical signal to noise ratio(OSNR)of24 d B,while the turbo coded system with transmission rate of 50 Gbit/s can achieve it within OSNR of 20 d B.

关键词： Bit error rate Decoding Error statistics Frequency division multiplexing Optical communication Optical signal processing Signal to noise ratio Turbo codes

A novel policy iteration algorithm for solving the optimal consensus control problem of a discrete-time multiagent system with unknown dynamics

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Science China(Information Sciences) 2023年第8期66卷 269-270页

作者： Wenkai XU Li WANG Shiwen SUN Chengyi XIA Zengqiang CHEN tianjin key laboratory of Intelligence computing and novel software technology Tianjin University of Technology The Engineering Research Center of Learning-Based intelligent System Ministry of Education College of Artificial Intelligence Nankai University

At present, an increasing number of researchers have noticed the importance of optimal consensus control(OCC) of multiagent systems(MASs) because of their rich practical applications in various areas [1–4]. To accomp...

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Highly birefringent photonic crystal fibers with flattened dispersion and low confinement loss

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Optoelectronics Letters 2013年第1期9卷 45-48页

作者：曹晔李荣敏童峥嵘 key laboratory of Film Electronics and Communication Devices Key Laboratory of Intelligent Computing and Novel Software Technology School of Computer and Communication Engineering Tianjin University of Technology

A highly birefringent index-guiding photonic crystal fiber (PCF) with flattened dispersion and low confinement loss is proposed by introducing two small air holes with the same diameter in the core area. The fundamental mode field, birefringence, confinement loss, effective mode area and dispersion characteristic of the fibers are studied by the full-vector finite element method (FEM). Simulation results show that a high birefringence with the order of 10 -3 and a low confinement loss of 0.001 dB/km are obtained at 1550 nm. Furthermore, flattened chromatic dispersion from 1450 nm to 1590 nm is obtained.

关键词：光子晶体光纤平坦色散高双折射损耗矢量有限元法气孔直径折射指数色散特性

Simultaneous measurement of refractive index, temperature and strain based on core diameter mismatch and polarization-maintaining FBG

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Optoelectronics Letters 2013年第3期9卷 238-240页

作者：童峥嵘王洁玉张卫华曹晔 key laboratory of Film Electronics and Communication Devices and key laboratory of intelligent computing and novel software technology School of Computer and Communication Engineering Tianjin University of Technology

A kind of fiber-optic sensor for simultaneous measurement of refractive index of surrounding medium, temperature and strain is described. Based on core diameter mismatch, a multimode-single mode-multimode (MSM) structure is presented. It is demonstrated that the three parameters can be measured respectively by the interference of the core mode and cladding modes excited in the single mode fiber (SMF). Then combined with a polarization-maintaining fiber Bragg grating (PMFBG) which has different sensing properties from MSM structure, three parameters are measured simultaneously. The experimental results show that PMFBG is insensitive to the refractive index and the refractive index sensitivity of the MSM structure is 96.04 nm·RIU^(-1); the temperature sensitivities of the characteristic wavelength for MSM structure and the center wavelengths of fast and slow axes for PMFBG are 0.0911 nm °C^(-1), 0.00976 nm °C^(-1) and 0.0105 nm °C^(-1), respectively; the strain sensitivities of those are -0.013 nm με^(-1), 0.012 nm με^(-1) and 0.012 nm με^(-1), respectively.

关键词：温度敏感性应变灵敏度同时测量折射率不匹配光纤光栅直径 MSM结构