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Optical generation of millimeter-wave by using external quadruplefrequency modulation technique

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Optical generation of millimeter-wave by using external quad...

A scalable code dissemination protocol in heterogeneous wireless sensor networks

国际纳光电子学研讨会

作者： Wei Zhang Xue Feng Xiaoming Liu State Key laboratory on Integrated Optoelectronics/tsinghua national laboratory for information science and technology tsinghua University Beijing 100084 china

＜正＞A technique to optically generate milimeter-wave based on external quadruple-frequency modulation is *** using two cascaded intensity modulators with a variable optical delay line,wideband continuously tunable m...

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science China(information sciences) 2012年第6期55卷 1323-1336页

作者： PENG ShaoLiang,LI ShanShan,LIAO XiangKe,PENG YuXing & XIAO Nong Department of Computer science,national University of Defense technology,Changsha 410073,China 1. Department of Computer science National University of Defense Technology Changsha 410073 China

Code dissemination is currently a major research issue in wireless sensor networks (WSNs).Many studies focus on code dissemination in homogeneous WSNs,mainly using a broadcast approach to solve this problem;few studies on code dissemination in heterogeneous ***,broadcasting cannot readily be used to solve the heterogenous WSN code dissemination problem directly,which is where we have focused our *** transformed this problem into a minimum non-leaf nodes (MNN) Steiner tree *** designed a scalable multicast protocol,named Heterogeneous Sensor Networks Scalable Reprogramming Protocol (HSR) to solve the MNN *** can build different multicast trees according to different nodes or code modules to disseminate different codes to *** is able to approximate the MNN tree problem to a ratio of ln|R| (R is the set of all destinations) best known lowest ***,the communication cost is significantly decreased and the total energy required by WSNs is *** further designed two scalable schemes,special routing log and hops-restricted local broadcast,which compress the multicast tree information and deliver the multicast messages without *** also designed a 3-stage pipeline to speed up the transmission of packets,which alleviated interference and hidden terminal *** evaluated our design through comprehensive simulations and prototype implementations on Mica2 *** results demonstrate that HSR outperforms previous protocols including the most recent studies on Sprinkler and uCast.

关键词： wireless sensor networks reprogramming code dissemination multicast scalable

A self-calibration algorithm for cross array in the presence of mutual coupling

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science China(information sciences) 2011年第4期54卷 836-848页

作者： HU XiaoQin 1,2,CHEN Hui 2,WANG YongLiang 2 & CHEN JianWen 2 1 College of Electronic science and Engineering,national University of Defense technology,Changsha 410073,China 2 Key lab of Wuhan Radar Academy,Wuhan 430019,China 1. College of Electronic science and Engineering National University of Defense Technology Changsha 410073 China2. Key Lab of Wuhan Radar Academy Wuhan 430019 China

In this paper,a novel blind mutual coupling self-calibration algorithm especially tailored to cross array is *** method compensates for the mutual coupling not only between sensors in each subarray but also between two *** the property of coupling matrix,the proposed method requires neither the calibration sources in known locations nor the multidimensional nonlinear *** method can jointly estimate the DOAs of the incoming signals and the unknown mutual coupling coefficients,and has high estimation precision and low computational *** analysis and computer simulations show the effectiveness of the proposed algorithm.

关键词： cross array mutual coupling self-calibration DOA estimation

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(k,n)真彩色扩展可视分存技术

武汉大学学报（理学版） 2008年第5期54卷 603-606页

作者：刘硕王道顺清华信息科学与技术国家实验室(筹)/清华大学计算机科学与技术系北京100084

针对目前彩色扩展可视分存方案(EVSS)的像素膨胀问题,本文在灰度(k,n)-EVSS方案基础上,给出一种通过修改黑白(k,n)可视分存方案(VSS)来构造真彩色的(k,n)方案的方法.用该方法构造出的可视分存方案,n个分存图具有不同意义的彩色图像,并... 详细信息

针对目前彩色扩展可视分存方案(EVSS)的像素膨胀问题,本文在灰度(k,n)-EVSS方案基础上,给出一种通过修改黑白(k,n)可视分存方案(VSS)来构造真彩色的(k,n)方案的方法.用该方法构造出的可视分存方案,n个分存图具有不同意义的彩色图像,并且像素膨胀与黑白(k,n)-VSS方案相同.

关键词：可视分存扩展可视分存覆盖图真彩色

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Log-Mining-Based Query Spelling Correction for Chinese Search Engines

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Log-Mining-Based Query Spelling Correction for Chinese Searc...

Super-orthogonal space-time code design based on the trellis diagram integrated operation

第四届全国信息检索与内容安全学术会议

作者： Bo ZHOU Min ZHANG Shaoping MA Yiqun LIU Liyun RU State Key laboratory of Intelligent technology and Systems tsinghua national laboratory for information science and technology Department of Computer science and technology,tsinghua University,Beijing 100084,China

Query spelling correction is crucial to search engines for improving web search relevance and user experience. Additional difficulty is posed beyond traditional lexicon-based spelling correction,since there exist vast amount of out-of-lexicon but legitimate terms in ***,context sensitive techniques cannot work due to the short query *** recent studies concentrate on spelling correction of English ***,in Chinese search engines,queries contain more mixed types of terms and more complicated spelling error patterns as compared to those in English search *** this paper,we analyze the types and patterns of query spelling errors in Chinese search *** using language-dependent error models,we present a query spelling correction approach for Chinese search engines,in which knowledge extracted from search log is *** experiments performed on randomly sampled real search queries show that % precision and % recall have been achieved.

关键词： Spelling Correction Query Log Search Engine

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science China(information sciences) 2011年第7期54卷 1481-1490页

作者： AO Jun 1,2,MA ChunBo 1,AO FaLiang 1 & LIAO GuiSheng 3 1 College of information and Communication,Guilin University of Electronic and technology,Guilin 541004,China 2 national Key laboratory of Electromagnetic Environment,QingDao,266107,China 3 national lab of Radar Signal Processing,Xidian University,Xi’an 710071,China 1. College of information and Communication Guilin University of Electronic and Technology Guilin 541004 China2. National Key Laboratory of Electromagnetic Environment QingDao 266107 China3. National Lab of Radar Signal Processing Xidian University Xi’an 710071 China

By studying the super-orthogonal space-time coding designs for 2 transmit antennas and superquasi orthogonal space-time coding designs for 4 transmit antennas,a novel super-orthogonal space-time coding design for 4 transmit antennas is *** exploiting the inherent structure association between OSTBC and QOSTBC,the proposed schemes can obtain the full-rate and good performance while keeping the coding complexity as super-orthogonal space-time coding schemes for 2 transmit *** results demonstrate that the proposed schemes outperforms the existing super-quasi orthogonal space-time coding schemes by almost 2 dB.

关键词： STBC TCM SOSTTC SQOSTTC

Medical image segmentation using improved FCM

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science China(information sciences) 2012年第5期55卷 1052-1061页

作者： ZHANG XiaoFeng 1,2,ZHANG CaiMing 1,3,4,TANG WenJing 1,2 & WEI ZhenWen 1 1 School of Computer science and technology,Shandong University,Jinan 250101,China 2 School of information and Electrical Engineering,Ludong University,Yantai 264025,China 3 School of Computer science and technology,Shandong University of Finance and Economics,Jinan 250014,China 4 Shandong Province Key lab of Digital Media technology,Jinan 250014,China 1. School of Computer science and technology Shandong University Jinan 250101 China2. School of Information and Electrical Engineering Ludong University Yantai 264025 China3. School of Computer Science and Technology Shandong University of Finance and Economics Jinan 250014 China4. Shandong Province Key Lab of Digital Media Technology Jinan 250014 China

Image segmentation is one of the most important problems in medical image processing,and the existence of partial volume effect and other phenomena makes the problem much more *** C-means,as an effective tool to deal with PVE,however,is faced with great challenges in *** at this,this paper proposes one improved FCM algorithm based on the histogram of the given image,which will be denoted as HisFCM and divided into two *** first phase will retrieve several intervals on which to compute cluster centroids,and the second one will perform image segmentation based on improved FCM *** with FCM and other improved algorithms,HisFCM is of much higher efficiency with satisfying *** on medical images show that HisFCM can achieve good segmentation results in less than 0.1 second,and can satisfy real-time requirements of medical image processing.

关键词： FCM histogram image segmentation medical image processing

(2,n)secret sharing scheme for gray and color images based on Boolean operation

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science China(information sciences) 2012年第5期55卷 1151-1161页

作者： DONG Lin 1,WANG DaoShun 1,LI ShunDong 2 & DAI YiQi 1 1 Department of Computer science and technology,tsinghua University,Beijing 100084,China 2 School of Computer science,Shaanxi Normal University,Xi'an 710062,China 1. Department of Computer science and technology Tsinghua University Beijing 100084 China2. School of Computer Science Shaanxi Normal University Xi’an 710062 China

Traditional secret sharing (SS) schemes can reconstruct the secret precisely,but have high com-putation *** secret sharing (VSS) schemes use human visual system to reconstruct the secret without cryptographic computation,but have pixel expansion and loss of *** et *** a (2,n)-SS scheme for binary images based on Boolean operation,which has low computation complexity,no pixel expansion and the contrast is 1/*** this paper,we first construct an r runs (2,n)-SS scheme to improve the contrast of Wang et al.'s binary (2,n)-SS *** we present two approaches to construct r runs (2,n)-SS schemes for grayscale image and color *** two approaches are both based on Boolean operation,while one approach uses halftone technology and the other uses bit level *** proposed schemes have low computation complexity and almost ideal contrast.

关键词： secret sharing scheme Boolean operation halftone contrast

Multiparty quantum secret sharing of classical and quantum messages

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Progress in Natural science:Materials International 2007年第1期17卷 26-31页

作者： CHEN Pan, DENG Fuguo and LONG Guilu ( Key laboratory for Quantum information and Measurements, and Department of Physics, tsinghua University, Beijing 100084, China Key laboratory of Beam technology and Material Modification, MOE, Institute of Low Energy Nuclear Physics, and Department of Material science and Engineering, Beijing Normal University, Beijing 100875, China Beijing Radiation Center, Beijing 100875, China Key laboratory for Atomic and Molecular Nano-sciences, tsinghua University, Beijing 100084, China) [a]Key laboratory for Quantum information and Measurements and Department of Physics Tsinghua University Beijing China [b]Key laboratory of Beam technology and Material Modification MOE Institute of Low Energy Nuclear Physics and Department of Material Science and Engineering Beijing Normal University Beijing China [c]Beijing Radiation Center Beijing China [d]Key laboratory for Atomic and Molecular Nano-sciences Tsinghua University Beijing China

A scheme for multiparty quantum secret sharing of classical and quantum messages is proposed by using entanglement swapping. This scheme can distribute not only the classical information but also the quantum informati... 详细信息

关键词： quantum secret sharing classical message quantum message EPR pair.