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一种基于空-时快速鲁棒特征的视频词汇的人行为识别方法

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上海交通大学学报 2011年第2期45卷 225-229页

作者：冯冰蒋兴浩孙锬锋上海交通大学信息安全工程学院上海200240 上海市信息安全综合管理技术研究重点实验室上海200240

提出了一种空-时快速鲁棒特征(SURF)描述子,并且结合视频词汇概念,应用于人行为识别.这种新的描述子在行为识别应用中能很好地体现视频的时空本质,通过词袋(Bag of Words)模型来表征视频,且在表征过程使用了非硬性权重.实验以瑞典皇家... 详细信息

提出了一种空-时快速鲁棒特征(SURF)描述子,并且结合视频词汇概念,应用于人行为识别.这种新的描述子在行为识别应用中能很好地体现视频的时空本质,通过词袋(Bag of Words)模型来表征视频,且在表征过程使用了非硬性权重.实验以瑞典皇家理工学院的行为识别数据集作为测试对象,使用了相关领域传统的分类策略,同时引入了包含二次判断的投票系统.实验结果证明,结合特征描述子和视频词汇的行为识别框架在速度和准确率上均优于已有的一些方法,同时该分类策略在某些行为类型上优于传统的分类方法,能有效地应用于行为识别领域.

关键词：空-时快速鲁棒特征行为识别视频词汇

Robust cooperative spectrum sensing schemes for fading channels in cognitive radio networks

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Science china(information Sciences) 2011年第2期54卷 348-359页

作者： YUE WenJing1,2, ZHENG BaoYu1,2, MENG QingMin1, CUI JingWu1 & XIE PeiZhong1 1Institute of Signal Processing and Transmission, Nanjing university of Posts and Telecommunications, Nanjing 210003, china 2Department of Electronic Engineering, shanghai jiaotong university, shanghai 200240, china 1. Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China

In cognitive radio systems, cooperative spectrum sensing can detect the presence of the primary user accurately. In practice, however, since the sensing observations are forwarded to a data collector through fading channels, the sensing performance is severely degraded. To deal with this problem, in this paper, we first propose a secondary user selection based cooperative spectrum sensing method to improve sensing performance by decreasing the reporting errors introduced by the fading channels. More specifically, only the secondary users with better signal-to-noise ratio (SNR) for reporting channels are allowed to send their local binary decisions (0 or 1) to the data collector while the others will send nothing. Additionally, we further propose a diversity based cooperative spectrum sensing method which applies existing space-time coding. By exploiting space diversity in CR network, the reporting errors introduced by the fading channel can be decreased and then the sensing performance is improved significantly. For either proposed cooperative spectrum sensing method, the sensing performance is derived and the analytical performance results are given. Our analysis and numerical results verify that proposed methods outperform the conventional cooperative spectrum sensing with OR-rule by taking into account the error effect on the reporting channels.

关键词： cognitive radio (CR) spectrum sensing energy detection diversity technique space-time coding

A Robust Interacting Multisensor State Fusion Based on Adaptive Outlier Controlling Multirate Model

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Journal of shanghai jiaotong university(Science) 2007年第5期12卷 577-583页

作者：牛沿茏李建勋 school of Electronic information and Electrical Eng. Shanghai Jiaotong Univ.

An adaptive outlier controlling multirate model based on Hong’s multirate kinetic model was represented in order to resist the outliers and utilize their useful information. Wavelet transform was introduced to detect and control the outliers. The multirate information extraction and the controlling of outliers were properly integrated to establish an adaptive outlier controlling multirate model. The proposed model was applied to multisensor state fusion with interacting multiple model (IMM), and a robust interacting multisensor state fusion algorithm was established based on adaptive outlier controlling multirate model. The Monte-Carlo simulation shows that it could improve the accuracy of fusion estimation by 70% compared to Hong’s algorithm and at least 14% to Xiao’s algorithm.

关键词： adaptive outlier controlling wavelet transform multirate model state fusion

Feasibility of Localizing in vivo Micro-devices with Electromagnetic Methods

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Journal of shanghai jiaotong university(Science) 2008年第5期13卷 559-561页

作者：郭旭东颜国正姜萍萍 school of Electronic Information and Electrical Engineering Shanghai Jiaotong University

In order to measure the location of medical micro-devices in the gastrointestinal tract, electro-magnetic methods were developed considering the magnetic permeability of human bodies. Two varieties of electromagnetic localization methods have been implemented: one uses direct current(DC) to generate the elec-tromagnetic field, and the other uses alternating current (AC). The two varieties of the localization principle were analyzed and relevant experiments were made. The experiments show that the alternating electromagnetic method acquires higher accuracy, higher stability and wider measurement range.

关键词： medical micro-devices position measurement electromagnetic field

Temperature Characteristics of Surface Acoustic Waves Propagating on La_3Ga_5SiO_4 Substrates

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Journal of Materials Science & technology 2004年第1期20卷 63-66页

作者： Guowei ZHANG, Wenkang SHI, Xiaojun JI, Tao HAN, Feng DU and Lianger LIschool of electronics & information, shanghai Jiao Tong university, shanghai 200030, china shanghai Jiao Tong Univ Sch Elect & Informat Shanghai 200030 Peoples R China

Langasite (LGS) is a novel piezoelectric crystal. The authors numerically analyses the temperature stability of surface acoustic waves (SAW) and the relation of SAW propagation with temperature on certain optimal cuts on LGS in this paper. The results show that LGS has better temperature stability than traditional piezo crystals. The results also demonstrate that the velocity of SAW decrease with temperature, the electro-mechanical coupling constant (k2) and temperature coefficient of frequency increases parabolically and the power flow angle increases linearly on certain optimal cuts of LGS. The calculation result compared with the experimental and show good agreement.

关键词： La3Ga5SiO4 (LGS) Surface acoustic wave (SAW) Temperature characteristic

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基于语义绑定的分层视觉词汇库的图像检索

上海交通大学学报 2011年第2期45卷 154-158页

作者：傅光磊孙锬锋蒋兴浩上海交通大学信息安全工程学院上海200240 上海市信息安全综合管理技术研究重点实验室上海200240

提出了一种解析复杂图像语义的模型——分层语义模型,给出了解析复杂语义和构造模型的方法.提出了基于分层语义模型的语义绑定的分层视觉词汇库的概念,给出了构造词汇库的具体方法和步骤,同时对词汇库细节问题给出了解决的方法.将提出... 详细信息

提出了一种解析复杂图像语义的模型——分层语义模型,给出了解析复杂语义和构造模型的方法.提出了基于分层语义模型的语义绑定的分层视觉词汇库的概念,给出了构造词汇库的具体方法和步骤,同时对词汇库细节问题给出了解决的方法.将提出的分层视觉词汇库应用于基于内容和语义的图像检索中,并给出了构建图像检索系统的方法和检索图像的步骤.该模型在图像检索中可同时满足基于图像内容的检索方式和基于图像语义的检索方式.实验结果表明,该方法比基于SIFT(Scale Invariant Feature Transform)特征向量的图像检索方法具有更好的性能.

关键词：图像语义分层语义模型分层视觉词汇库图像检索

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基于双重检测模型的视频镜头分割算法

上海交通大学学报 2011年第10期45卷 1542-1546页

作者：巢娟孙锬锋蒋兴浩上海交通大学信息安全工程学院上海200240 上海市信息安全综合管理技术研究重点实验室上海200240

提出一种基于自适应双重检测模型的视频镜头分割算法.该算法分为初检和复检两阶段,初检提出了基于人类视觉特征的非均匀分块的概念,并结合滑动窗口自适应二分查找算法进行镜头边界检测;复检过程利用尺度不变特征变换算法对初检得到的镜... 详细信息

提出一种基于自适应双重检测模型的视频镜头分割算法.该算法分为初检和复检两阶段,初检提出了基于人类视觉特征的非均匀分块的概念,并结合滑动窗口自适应二分查找算法进行镜头边界检测;复检过程利用尺度不变特征变换算法对初检得到的镜头边界进行匹配,排除初检中的误检.视频测试结果表明,该算法对多种不同类型的视频能同时提高切变和渐变镜头边界检测的效果.

关键词：镜头分割双重检测非均匀分块自适应二分查找尺度不变特征变换算法

Optimal power allocation for cognitive relay networks: amplify-and-forward versus selection relay

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Science china(information Sciences) 2011年第4期54卷 861-872页

作者： YUE WenJing 1,2,ZHENG BaoYu 1,2,MENG QingMin 1,YUE WenJie 3 & CUI JingWu 1 1 Institute of Signal Processing and Transmission,Nanjing university of Posts and Telecommunications,Nanjing 210003,china 2 Department of Electronic Engineering,shanghai jiaotong university,shanghai 200240,china 3 Shanxi Institute of Educational Science,Taiyuan 030009,china 1. Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China3. Shanxi Institute of Educational Science Taiyuan 030009 China

We consider a cognitive relay network which is defined by a source,a destination,and cognitive relay nodes and primary user *** this network,a source is assisted by cognitive relay nodes which allow coexisting with primary user nodes by imposing severe constraints on the transmission power so that they operate below the noise floor of primary user *** this paper,we mainly study the power allocation strategies of this system to minimize the outage probability subject to total and individual power constraints for cognitive relay nodes and subject to interference constraints for primary user nodes.A relay transmission scheme,namely amplify-and-forward (AF),is *** first present an optimal power allocation (OPA) scheme to minimize the system outage probability,based on instantaneous channel state information among the source,destination and relay nodes and mean channel gains between primary user nodes and cognitive ***,we propose a selection AF scheme (S-AF) where the single best relay is chosen to assist in the transmission and study power allocation strategy for S-AF to minimize outage *** analytical power allocation strategies have been validated through numerical *** results indicate that the AF with OPA and S-AF with OPA have significantly better outage behavior and average throughput than AF and S-AF schemes *** also find that S-AF with OPA achieves a higher throughput,and hence lower outage probability than AF with OPA.

关键词： cognitive radio (CR) relay networks power allocation outage probability

A current-mode RF transmitter for 6–9 GHz MB-OFDM UWB application

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Science china(information Sciences) 2011年第2期54卷 419-428页

作者： CHEN YunFeng1, FAN JinHan1, LI Wei1, LI Ning1 & REN JunYan1,2 1State Key Laboratory of ASIC & System, Fudan university, shanghai 201203, china 2Micro-/Nano-electronics Science and technology Innovation Platform, Fudan university, shanghai 201203, china 1. State Key Laboratory of ASIC & System Fudan University Shanghai 201203 China2. Micro-/Nano-Electronics Science and Technology Innovation Platform Fudan University Shanghai 201203 China

This paper presents a current-mode 6–9 GHz RF transmitter for MB-OFDM UWB systems. The proposed current-mode transmitter consists of current-mode IQ LPF, current mirror amplifier, IQ up-conversion mixer (up-mixer), differential power driver amplifier (PA) and high-speed divider with LO buffers for generating IQ LO signals. All circuits are designed to possess high linearity and wide bandwidth. The transmitter is fabricated in TSMC 0.13 μm 1P8M RF CMOS technology with a die area of 1.56 mm2. Measurement results show that a maximum output power of -0.7 dBm with an LO leakage/sideband rejection ratio (LOL/SB RR) around -33/ - 35 dBc is achieved, and that this transmitter excels the traditional voltage-mode counterpart in terms of high linearity (about +1 dBm output 1-dB compression point, +10 dBm output IP3 in average) with comparable power consumption (drawing 48 mA current from 1.2 V supply).

关键词： current-mode RF transmitter high linearity MB-OFDM UWB high speed divider CMOS