检索结果-南通市图书馆

Analysis of a kind of quantum cryptographic schemes based on secret sharing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2009年第9期52卷 1313-1316页

作者： ZHAng XingLan1 & JI DongYao2 1 College of computer Science and Technology, beij.ng university of Technology, beij.ng 100124, china 2 State Key Laboratory of information Security, Graduate university of Chinese Academy of Sciences, beij.ng 100049, china College of computer Science and Technology Beijing University of Technology Beijing 100124 China State Key Laboratory of information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China

Recently, Yang et al. proposed a kind of quantum cryptographic schemes based on secret sharing. The main idea is drawn from the case, where any n participants who share a secret K can co-operate as K does. This process can be applied to encryption, authentication, signature and so on. Unfortunately, since there is no identity authentication of the share's holder, these schemes inherit the limitation of secret sharing in practice. If some participants do not follow the protocol, the protocol would be a failure at last. Moreover, these schemes encounter another serious attack. Any two participants can co-operate to defeat the schemes by sending different shares to the parties unknown to the distributor of the secret K, such that these parties can execute the protocol as well. The attack proves that it is not enough for quantum cryptographic schemes that only the secret key is secure.

关键词： quantum identity authentication quantum secure direct communication quantum signature secret sharing

维普期刊数据库

Right-and-left visual field stimulation:A frequency and space mixed coding method for SSVEP based brain-computer interface

在线全文

学校读者我要写书评

暂无评论

Science china(information Sciences) 2011年第12期54卷 2512-2518页

作者： YAN Zheng, GAO XiaoRong & GAO ShangKai Department of Biomedical Engineering, School of Medicine, tsinghua university, beij.ng 100084, china 1. Department of Biomedical Engineering School of Medicine Tsinghua University Beijing 100084 China

On the condition of using limited frequencies, fewer targets could be presented in brain-computer interface (BCI) based on steady-state visual evoked potentials (SSVEP). This paper proposes a novel coding method for SSVEP that, through a combination of frequency and spatial information, could increase the number of targets. Each target was composed of two flickers placed in the right-and-left visual fields. Given the role of the optic chiasm in the vision pathway, the two frequency components could be projected to contralateral occipital regions. Canonical correlation analysis (CCA) was utilized to detect the frequency components from the right or left visual cortex. Asymmetric index as a supplementary feature was also computed. Linear discriminant analysis (LDA) was used for target recognition. The attractive feature of this method is that it would substantially increase the number of targets. If the number of frequency was N, the method could present N times more targets than conventional SSVEP-based BCIs.

关键词： brian-computer interface (BCI) frequency-space mixed coding steady-state visual evoked potential (SSVEP)

High-speed reconstruction for ultra-low resolution faces

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(information Sciences) 2012年第9期55卷 2102-2108页

作者： WAng Li ,CHEN JianSheng,HE JinPing & SU GuangDa Department of Electronic Engineering,tsinghua university,beij.ng 100084,china 1. Department of Electronic Engineering Tsinghua University Beijing 100084 China

In this paper,a learning-based high-speed reconstruction system for ultra-low resolution faces is implemented using a software/hardware co-design *** hardware component working at 60 MHz contains a field programmable gate array,which is reconfigured to contain parallel processing units,and multiple memories to create parallel *** hardware component effectively handles generating and sorting computationally intensive similarity *** solves the processing speed problem in learning-based super-resolution reconstruction for ultra-low resolution *** system can reconstruct faces using 8 × 6,16 × 12,and 32 × 24 sized images,with 4 × 4,8 × 8,or 16 × 16 times *** experimental results verify the effectiveness of our system in terms of both visual effect and low root mean square *** processing speed can be improved up to a maximum of 7900 times faster than a pure software implementation using C.

关键词： neighborhood image parallel computer template matching pixel compensation pipeline

Capability of evolutionary cryptosystems against differential cryptanalysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(information Sciences) 2011年第10期54卷 1991-2000页

作者： ZHAng Huanguo 1,2 ,LI ChunLei 1,2 & TAng Ming 1,2 1 School of computer,Wuhan university,Wuhan 430072,china 2 Key Laboratory of Aerospace information Security and Trusted Computing of Ministry of Education,Wuhan university,Wuhan 430072,china 1. School of computer Wuhan University Wuhan 430072 China2. Key Laboratory of Aerospace Information Security and Trusted Computing of Ministry of Education Wuhan University Wuhan 430072 China

The evolutionary cryptosystem is a new *** paper studies its security level resisting against differential *** is shown that the evolutionary cryptosystem possesses higher resistance than its initial fixed cryptosystem against differential *** the basis of the relationship among the data complexity,the bit advantage and the success rate of differential cryptanalysis,it is proven that more data is needed for attacking the evolutionary cryptosystem when the bit advantage and success rate are ***,it is shown that the time complexity for attacking the evolutionary cryptosystem is higher than that of differential attacking its initial fixed cryptosystem with the same amount of plaintext-ciphertext *** research indicates that the evolutionary cryptosystem is more robust than its initial fixed cryptosystem against differential cryptanalysis.

关键词： information security cryptology evolutionary cryptosystem cryptanalysis differential cryptanalysis

Channel-aware and queue-aware joint-layer resource optimization for cognitive radio networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(information Sciences) 2010年第12期53卷 2576-2583页

作者： GUO KunQi 1,2,SUN LiXin 1,LI Yong 2 & JIA ShiLou 3 1 School of computer Science and Telecommunication Engineering,Jiangsu university,Zhenjiang 212013,china 2 Research center for Wireless Communication,Shanghai Institute of Microsystem and information Technology,Chinese Academy of Sciences,Shanghai 200050,china 3 Communication Research center,Harbin Institute of Technology,Harbin 150001,china 1. School of computer Science and Telecommunication Engineering Jiangsu University Zhenjiang 212013 China2. Research Center for Wireless Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China3. Communication Research Center Harbin Institute of Technology Harbin 150001 China

An optimization model is derived to maximize the utilization efficiency of the idle channels of primary users(PU) in cognitive radio *** the optimization model,Lyapunov optimization method is used to allocate the idle channels of PU to secondary user(SU) most *** time distribution of the idle channels of PU is predicted by a low-pass time *** algorithm is proposed to implement the optimization *** algorithm is efficient because of using a greedy selection *** efficiency of the algorithm is demonstrated by mathematic analyses and simulation results.

关键词： cognitive radio networks Lyapunov optimization resource utilization primary user secondary user

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

教育系统中主动数据服务技术的研究与实现

实验技术与管理 2011年第4期 266-268页

作者：胡南佟秋利清华大学计算机与信息管理中心

现代信息技术的发展使得教育系统中的主动式数据服务开始成为热点。借助主动数据服务,系统管理人员可以设置主动规则(ECA规则)使数据库能独立地管理信息。针对校园应用的特点,可以对ECA规则进行扩展,使得扩展后的规则(X-ECA)可以使用相... 详细信息

现代信息技术的发展使得教育系统中的主动式数据服务开始成为热点。借助主动数据服务,系统管理人员可以设置主动规则(ECA规则)使数据库能独立地管理信息。针对校园应用的特点,可以对ECA规则进行扩展,使得扩展后的规则(X-ECA)可以使用相同的模型对不同事件或操作过程进行抽象。此外,这种基于X-ECA的架构能够以组件形式与现有应用衔接,避免了繁琐的部署流程。

关键词：主动数据服务主动规则 ECA X-ECA

Corner occupying theorem for the two-dimensional integral rectangle packing problem

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(information Sciences) 2012年第11期55卷 2466-2472页

作者： HUAng WenQi1,YE Tao1 & CHEN DuanBing2 1School of computer Science and Technology,Huazhong university of Science and Technology,Wuhan 430074,china 2Web Sciences center,School of computer Science,university of Electronic Science and Technology of china,Chengdu 611731,china 1. School of computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China2. Web Sciences Center School of Computer Science University of Electronic Science and Technology of China Chengdu 611731 China

This paper proves a corner occupying theorem for the two-dimensional integral rectangle packing problem,stating that if it is possible to orthogonally place n arbitrarily given integral rectangles into an integral rectangular container without overlapping,then we can achieve a feasible packing by successively placing a rectangle onto a bottom-left corner in the *** on this theorem,we might develop e?cient heuristic algorithms for solving the integral rectangle packing *** fact,as a vague conjecture,this theorem has been implicitly mentioned with different appearances by many people for a long time.

关键词： rectangle packing bottom-left corner occupying theorem NP hard

Deterministic secure quantum communication without unitary operation based on high-dimensional entanglement swapping

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(information Sciences) 2012年第2期55卷 360-367页

作者： LIU ZhiHao1,CHEN HanWu1,LIU WenJie2,XU Juan1 & LI ZhiQiang3 1School of computer Science and Engineering,Southeast university,Nanjing 211189,china 2School of computer and Software,Nanjing university of information Science & Technology,Nanjing 210044,china 3College of information Engineering,Yangzhou university,Yangzhou 225009,china 1. School of computer Science and Engineering Southeast University Nanjing 211189 China2. School of Computer and Software Nanjing University of Information Science & Technology Nanjing 210044 China3. College of Information Engineering Yangzhou University Yangzhou 225009 China

By analysis of the basic properties of entanglement swapping of high-dimensional Bell states,a universal and general deterministic secure quantum communication(DSQC)protocol is proposed,in which unitary operation is not *** making use of the results of high-dimensional Bell measurement,the sender and the receiver can encode and decode the message respectively by performing the modular addition and *** mutually complementary bases are constructed;and according to the property of mutual complement,a method for checking security of the high-dimensional quantum channel is put *** common attack strategies are analyzed,and the corresponding error rates are *** the upper bound of the threshold of error rate is deduced.

关键词： deterministic secure quantum communication high-dimensional Bell state entanglement swap-ping high-dimensional Bell measurement

Study on NDVI-T_s space by combining LAI and evapotranspiration

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第7期49卷 747-754页

作者： HAN Lijuan1,2,3, WAng Pengxin4, YAng Hua1,2,3, LIU Shaomin1,2,3 & WAng Jindi1,2,3 1. Research center for Remote Sensing and GIS, School of Geography, beij.ng Normal university, beij.ng 100875, china 2. State Key Laboratory of Remote Sensing Science, beij.ng 100875, china 3. beij.ng Key Laboratory for Remote Sensing of Environment and Digital Cities, beij.ng 100875, china 4. Department of information management, College of information and Electronic Engineering, china Agricultural university, beij.ng 100083, china 1. Research center for Remote Sensing and GIS School of Geography Beijing Normal University Beijing 100875 China 2. State Key Laboratory of Remote Sensing Science Beijing 100875 China 3. beij.ng Key Laboratory for Remote Sensing of Environment and Digital Cities Beijing 100875 China 4. Department of information management College of Information and Electronic Engineering China Agricultural University Beijing 100083 China

This paper focuses on interpreting the different spatial relationships between NDVI and Ts, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Tempera-ture-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and Ts are useful for describing, validating and updating land surface models.

关键词： NDVI, land surface temperature, evapotranspiration, leave area index.

维普期刊数据库