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Combining Digital Watermarks with Two-Color Bitmap Image

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The Journal of china Universities of posts and telecommunications 2000年第Z1期 31-35页

作者： SAAD A Amer, YANG Yi-xian (Information Security Center, beijing university of posts and telecommunications, beijing 100876, P.R. china)

A technology for combining digital watermarks with two-color bitmap image based on the threshold watermarking method is presented. Our technology doesn’t add any thing to the digital media, but combines the watermarks in two-color bitmap image by looking for some characteristic values in the bitmap and uses the relationship between the watermarks and the characteristic values to prove the copyright protection. The choice of the characteristic values depends on the choice of a cryptographic key known by the owner of the bitmap. The benefit of using a cryptographic key is to combine the watermarks with the bitmap in a high secure way.

关键词： digital watermarks information hiding copyright protection

Quantum threshold group signature

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science china(Physics,Mechanics & Astronomy) 2008年第10期51卷 1505-1514页

作者： YANG YuGuang1,2,3 & WEN QiaoYan4 1 College of Computer science and Technology, beijing university of Technology, beijing 100124, china 2 State Key Laboratory of Integrated Services Network, Xidian university, Xi’an 710071, china 3 State Key Laboratory of Information Security (Graduate university of Chinese Academy of sciences), beijing 100049, china 4 State Key Laboratory of Networking and Switching Technology, beijing university of posts and Tele-communications, beijing 100876, china College of Computer science and Technology Beijing University of Technology Beijing 100124 China State Key Laboratory of Integrated Services Network Xidian University Xi’an 710071 China State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

In most situations, the signer is generally a single person. However, when the message is written on behalf of an organization, a valid message may require the approval or consent of several persons. Threshold signature is a solution to this problem. Generally speaking, as an authority which can be trusted by all members does not exist, a threshold signature scheme without a trusted party appears more attractive. Following some ideas of the classical Shamir’s threshold signature scheme, a quantum threshold group signature one is proposed. In the proposed scheme, only t or more of n persons in the group can generate the group signature and any t-1 or fewer ones cannot do that. In the verification phase, any t or more of n signature receivers can verify the message and any t-1 or fewer receivers cannot verify the validity of the signature.

关键词： threshold quantum signature trusted party quantum cryptography

Novel resource allocation algorithms for multiuser downlink MIMO-OFDMA of FuTURE B3G systems

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Progress in Natural science:Materials International 2009年第9期19卷 1141-1146页

作者： Qiaoyun Sun, Hui Tian *, Shuang Wang, Kun Dong, Ping Zhang Key Laboratory of Universal Wireless Communication, Ministry of Education, Wireless Technology Innovation Institute, beijing university of posts & telecommunications, beijing 100876, china [a]Key Laboratory of Universal Wireless Communication Ministry of Education Wireless Technology Innovation Institute Beijing University of Posts & Telecommunications Beijing 100876 China

In this paper, subcarrier and power allocation problems for multiuser downlink MIMO-OFDMA of the FuTURE B3G TDD system are investigated. For the reciprocity of the TDD channel, the channel state information can be employed at the transmitter, thus eigen beamforming can be implemented efficiently. With the goal of minimizing the total transmit power under the condition that the QoS requirement of each user can be guaranteed, a novel dynamic resource allocation scheme is proposed to exploit the multiuser diversity gain. The proposed algorithm involves adaptive subcarrier allocation, adaptive modulation and eigen beamforming and achieves significant improvement in overall system performance. Based on the proposed scheme, a modified bit and power allocation is developed. The modified scheme reduces the computational complexity at little expense of system performance. Numerical simulations show that the proposed algorithm and the modified scheme can decrease the total transmit power effectively.

关键词： Adaptive modulation and coding Dynamic resource allocation Eigen beamforming MIMO–OFDMA

Threshold proxy quantum signature scheme with threshold shared verification

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science china(Physics,Mechanics & Astronomy) 2008年第8期51卷 1079-1088页

作者： YANG YuGuang1,3,4 & WEN QiaoYan2 1 College of Computer science and Technology,beijing university of Technology,beijing 100124,china 2 State Key Laboratory of Networking and Switching Technology,beijing university of posts and Tele-communications,beijing 100876,china 3 State Key Laboratory of Integrated Services Network,Xidian university,Xi’an 710071,china 4 State Key Laboratory of Information Security(Graduate university of Chinese Academy of sciences) ,beijing 100049,china 1. College of Computer science and Technology Beijing University of Technology Beijing 100124 China 3. State Key Laboratory of Integrated Services Network Xidian University Xi’an 710071 China 4. State Key Laboratory of Information Security (Graduate university of Chinese Academy of sciences) Beijing 100049 China 2. State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

A threshold proxy quantum signature scheme with threshold shared verification is proposed. An original signer could authorize a group as its proxy signers. Then only t or more of n persons in the proxy group can generate the proxy signature on behalf of the original signer and any t-1 or fewer ones cannot do that. When the proxy signature needs to be verified,any t or more of n persons belonging to the verification group can verify the message and any t-1 or fewer ones cannot verify the validity of the proxy signature.

关键词： quantum signature threshold proxy quantum group signature threshold shared verification

Practical conditions of signal space alignment for generalized MIMO Y channel

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science china(Information sciences) 2012年第10期55卷 2171-2182页

作者： SHE JiaJu 1,2,CHEN ShanZhi 1,2,HU Bo 1,WANG YingMin 2 & SU Xin 2 1 State Key Laboratory of Networking and Switching Technology,beijing university of posts and telecommunications,beijing 100876,china 2 State Key Laboratory of Wireless Mobile Communications,china Academy of telecommunications Technology,beijing 100191,china 1. State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China2. State Key Laboratory of Wireless Mobile Communications China Academy of Telecommunications Technology Beijing 100191 China

This paper proposes a generalization for applications of signal space alignment(SSA) in a generalized multiple input multiple output(MIMO) Y channel with K(K 2) nodes and an intermediate *** on that generalization,a method is introduced to determine the practical conditions for *** first study the generalized MIMO Y channel model with general signal demands;then,the degrees of freedom(DoF) achieved are given and are proved using *** SSA could decrease the number of antennas at the relay,it places new restrictions on the numbers of antennas at the *** then introduce a method to compare the models with and without SSA network coding(SSA-NC),mainly from the perspective of the total number of antennas *** results show that if each node must be able to exchange signals with all others,the model with SSA will definitely use more antennas to supply the same DoF,when K > *** it is not necessary for every node to exchange signals with all others,the comparison can still be made by using the method introduced *** a result,the conditions under which SSA-NC is needed are presented.

关键词： Signal space alignment MIMO Y channel degrees of freedom number of antennas

Threshold quantum secret sharing between multi-party and multi-party

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science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1308-1315页

作者： YANG YuGuang1,2,3 & WEN QiaoYan4 1 College of Computer science and Technology,beijing university of Technology,beijing 100124,china 2 State Key Laboratory of Integrated Services Network,Xidian university,Xi’an 710071,china 3 State Key Laboratory of Information Security (Graduate university of Chinese Academy of sciences),beijing 100049,china 4 State Key Laboratory of Networking and Switching Technology,beijing university of posts and Tele-communications,beijing 100876,china College of Computer science and Technology Beijing University of Technology Beijing 100124 China State Key Laboratory of Integrated Services Network Xidian University Xi’an 710071 China State Key Laboratory of Information Security (Graduate university of Chinese Academy of sciences) Beijing 100049 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

A threshold quantum secret sharing (TQSS) scheme between multi-party and multi-party was proposed using a sequence of single photons,which is useful and efficient when the parties of communication are not all present. We described the process of this TQSS scheme and discussed its security. It was shown that entan-glement is not necessary for quantum secret sharing. Moreover,the theoretic effi-ciency was improved to approach 100% as almost all the instances can be used for generating the private key,and each photon can carry one bit of information. This protocol is feasible with the present-day technique.

关键词： threshold quantum secret sharing quantum cryptography single photon multi-party and multi-party

Performance evaluation of channel inversion precoding for downlink multi-user MIMO system

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The Journal of china Universities of posts and telecommunications 2009年第5期16卷 20-24页

作者： CHEN Zhi-yong , WANG Wen-bo, PENG Mu-gen, LI Ren Wireless Signal Processing and Network Laboratory, Key Laboratory of Universal Wireless Communication, Ministry of Education, beijing university of posts and telecommunications, beijing 100876, china [a]Wireless Signal Processing and Network Laboratory Key Laboratory of Universal Wireless Communication Ministry of Education beijing university of posts and telecommunications beijing 100876 china

In downlink multi-user multi-input multi-output （MU-MIMO） system, not every user （user equipment （UE）） can calculate accurately signal to interference and noise ratio （SINR） without prior knowledge of the other users＇ precoding vector. To solve this problem, this article proposes a channel inversion precoding scheme by using the lower bound of S1NR and zero-forcing （ZF） algorithm. However, the SINR mismatch between lower bound SINR and actual SINR causes the inaccurateness of adaptive modulation and coding （AMC）. As a result, it causes degradation in performance. Simulation results show that channel inversion precoding provides lower throughput than that of single user multi-input multi-output （SU-MIMO） at high signal-to-noise ratio （SNR）（〉14 dB）, due to the SINR mismatch, although the sum-rate of channel inversion precoding is higher than that of SU-MIMO at full SNR regime.

关键词： MU-MIMO channel inversion precoding CQI feedback AMC lower bound S1NR zero-forcing

Capacity analysis and optimal power allocation for coordinated transmission in MIMO-OFDM systems

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science china(Information sciences) 2012年第6期55卷 1372-1387页

作者： CUI QiMei 1,HUANG XueQing 1,LUO Bing 1,TAO XiaoFeng 1 & JIANG Jun 2 1 Key Laborary of Universal Wireless Communications,beijing university of posts and telecommunications,beijing 100876,china 2 StarPoint Communication Software Company Ltd.,beijing 100102,china 1. Key Laborary of Universal Wireless Communications Beijing University of Posts and Telecommunications Beijing 100876 China2. StarPoint Communication Software Company Ltd. Beijing 100102 China

Coordinated transmission in multicell coordination networks has attracted much attentions in recent *** the paper,we investigate one open problem in the above area,which is concerned with how to solve the closed-form optimal power allocation scheme of coordinated transmission in downlink orthogonal frequency-division multiplexing (OFDM) systems with multiple antenna configurations and individual power constraints.A frequency-selective fading multiple-input multiple-output (MIMO) channel is *** derive the closed-form solutions of sum-rate capacity and optimal power allocations for coordinated transmission under the diversity case and the multiplexing case by solving the constrained optimization *** simulations are performed to verify the derived theoretical conclusions by means of comparing the proposed optimal power allocation (OPA) scheme with the other two typical power allocation *** is the power allocation scheme combining traditional water-filling with equal power (WS-EF PA).The other is equal power allocation (EPA) scheme.

关键词： coordinated multi-point transmission multicell cooperation capacity analysis MIMO-OFDM power allocation frequency selective MIMO channel

Simulation of moving boundary of the reaction shaft in a flash smelting furnace

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Journal of Central South university 2001年第3期13卷 213-218页

作者： CHEN Zhuo 1,MEI Chi 1,CHEN Hong-rong 1,MO Jiao 2 (1 Institute on Simulation and Optimization of Pyro-installation, Central Sout h university, Changsha 410083, china 2 science School, beijing university of posts and telecommunications, beijing 1 1. Institute on Simulation and Optimization of Pyro-installation Central South University 410083 Changsha China 2. science School Beijing University of Posts and Telecommunications 100876 Beijing China

As to solve the online monitoring of the inner temperatur e and freezing profile of the reaction shaft of flash smelting furnace, simulation of the wall in the reaction shaft in a flash smelting furnace was made through numerical computation. The computational results are very near the data got in s ite. The error of the moving boundary is approximately 3%, and that of the tempe rature is less than 5%. It is proved that the simulation software is applicable for practice to monitor the temperature and moving boundary inside the hearth on line. Based on a large number of the data computed, the relation between the cha nge of the moving boundary and inner temperature is summarized, and the great in fluence of the cooling system on the forming and stability of the moving boundar y inside the hearth is emphasized, which provide the theoretical bases for optim izing the flash smelting operation.

关键词： flash smelting furnace moving boundary numerical computation simulation