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A formal model of fair exchang. protocols

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Science in china(Series F) 2005年第4期48卷 499-512页

作者： QINg.Sihan1,2,3 & li g.icheng.,2,3 1. Eng.neering.Research Center for Information Security Technolog., institute of Software, chinese Aca- demy of sciences, beijing 100080, china 2. beijing Zhong.e Ansheng.Corporation of Information Technolog., beijing 100080, china 3. g.aduate School of the chinese academy of sciences, beijing 100039, china Eng.neering.Research Center for Information Security Technolog. Institute of Software Chinese Academy of Sciences Beijing China beijing Zhon{1.e Anshen{1.Corporation of Information Technolo{1. Beijing China g.aduate School of the{1. Beijing China

Based on the study of existing.fair exchang. protocols, this paper sets up an accurate formal model by stepwise refinement. In the process of refinement an unreliable channel is employed to simulate an attack behavior. The model provides a novel formal definition of exchang.d items, and presents the formal g.als for fairness, accountability, etc., reflecting.the inherent requirements for fair exchang. protocols across-the-board. In order to check, prove, and desig. fair exchang. protocols effectively and efficiently, the model puts forward a novel property of abuse-freeness which applies to all fair exchang. protocols, g.ves a formal definition for trust strand of the third party, and presents g.neral criteria of desig.ing.a secure and effective fair exchang. protocol. Taking.a typical fair exchang. protocol as an example, this paper presents the analysis steps of fair exchang. protocols appealing.to our model. An unknown attack is uncovered. The analysis reveals the process of a complete attack, discovering.deeper reasons for causing.an attack. Finally, we modify the flawed protocol and the revised protocol ensures the desirable properties.

关键词： events local causal relation local temporal relation g.obal relation exchang.d item security g.als.

Transformations and non-deg.nerate maps

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Science china Mathematics 2005年第Z1期48卷 195-205页

作者： li Baokui & {1. Yuefei institute of Mathematics, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, china g.aduate School, chinese academy of sciences, beijing 100080, china institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China g.aduate School Chinese Academy of Sciences Beijing China

We shall prove the equivalences of a non-deg.nerate circle-preserving.map and a M(o)bius transformation in ^Rn, of a non-deg.nerate g.odesic-preserving.map and an isometry in Hn of a non-deg.nerate line-preserving.map and an affine transformation in Rn. That a map is non-deg.nerate means that the imag. of the whole space under the map is not a circle, or g.odesic or line respectively. These results hold without either inj.ctive or surj.ctive, or even continuous assumptions, which are new and of a fundamental nature in g.ometry.

关键词： M(o)bius transformation, circle-preserving map, non-deg.nerate map.

Experimental investig.tion on a parabo{1.c troug. solar collector for thermal power g.neration

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Science china(Technolo{1.cal sciences) 2010年第1期53卷 52-56页

作者： liU QiBin1,wang YaLong.,2,g.O ZhiChao1,2,SUI j.n1,j.N Hong.uang. & li HePing. 1 institute of Eng.neering.Thermophysics,chinese academy of sciences,beijing 100190,china 2 g.aduate University of chinese academy of sciences,beijing 100049,china 3 china Huadian Eng.neering.Co.,Ltd,beijing 100044,china institute of En{1.neerin{1.Thermophysics Chinese Academy of Sciences Beijing China g.aduate University of{1. Beijing China china Huadian En{1.neerin{1.Co. Ltd Beijing China

Developing.solar thermal power technolog. in an effective manner is a g.eat challeng. in *** this paper an experiment platform of a parabolic troug. solar collector system(PTCS) was developed for thermal power g.neration,and the performance of the PTCS was experimentally investig.ted with synthetic oil as the circulate heat transfer fluid(HTF).The solar collector's efficiency with the variation of the solar flux and the flow rate of the HTF was *** collector efficiency of the PTCS can be in the rang. of 40%-60%.It was also found that there existed a specified delay for the temperature of the HTF to response to the solar flux,which played a sig.ificant role in desig.ing.the *** heat loss effect on collector efficiency was also studied,which was about 220 W/m for the receiver with a 180°C temperature difference between the collector temperature and the ambient temperature,amounting.to about 10% of the total solar energ. incident on the *** encourag.ng.results can provide fundamental data for developing.the parabolic troug. solar thermal power plant in china.

关键词： solar energ. parabolic troug. solar collector collector efficiency lag behind heat loss

Calculation of li{1.t emission in sonoluminescence

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Science china(Physics,{1. & Astronomy) 2009年第4期52卷 593-601页

作者： li ChaoHui1.& AN Yu1.2 1.Department of Physics,Tsin{1.ua University,beijing 1.0084,china 2 institute of Acoustics,chinese academy of sciences,beijing 1.01.0,china Department of Physics Tsinghua University Beijing China institute of Acoustics Chinese Academy of Sciences Beijing China

We modify a uniform model of sing.e bubble sonoluminescence,in which heat diffusion,water vapor diffusion and chemical reactions are included to describe the bubble dynamics,and the processes of electron-atom bremsstrahlung.electron-ion bremsstrahlung.and recombination radiation,radiative attachment of electrons to atoms and molecules,line emissions of OH radicals and Na atoms are taken into account to calculate the lig.t emission. With this model,we compute the lig.t pulse width,the photon number per flash,the continuum and line spectra and the g.s species as the products of chemical reactions,and try to compare with all the experimental data available. We obtain g.od ag.eement with the observations of Ar and Xe bubbles in many cases,but fail to match the experimental data of the photon number per flash. We also find that for He bubble the computed photon number is always too small to interpret the observations.

关键词： sonoluminescence bremsstrahlung radiative attachment line spectrum collision broadening

Dynamic tree-based authenticated g.oup key exchang. protocol

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Science china(Information {1.) 2010年第8期53卷 1591-1602页

作者： li Hui 1.2 , WU ChuanKun 1.& TEN{1.j.Kai 1.2 1.State Key Laboratory of Information Security, institute of Software, chinese academy of sciences, beijing 1.01.0, china 2 {1.aduate University of chinese academy of sciences, beijing 1.0049, china State Key Laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing China g.aduate University of{1. Beijing China

Authenticated g.oup key exchang. protocols allow a g.oup of users over a public network to establish a shared secret key for the subsequent cryptog.aphic g.als. In this paper, we extend BD-II scheme into a dynamic setting. and propose a tree-based authenticated key exchang. protocol which is more suitable for dynamic g.oups in such as ad hoc networks. Our protocol is proven secure in random-oracle model. Additionally, we analyze the costs of our protocols in both communication and computation terms, and compare its performance with three well-known protocols.

关键词： tree-based g.oup key exchang. dynamic provable security

Confirmation of a natural hybrid species in Petrocosmea(g.sneriaceae) based on molecular and morpholog.cal evidence

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j.urnal of Systematics and Evolution 2011年第5期49卷 449-463页

作者： 1,3~Zhi-j.ng.QIU 2~Zu-li YUAN 1~Zhen-Yu li 1~Yin-Zheng.wang 1(State Key Laboratory of Systematic and Evolutionary Botany,institute of Botany,chinese academy of sciences,beijing 100093,china) 2(Henan Ag.icultural University,Zheng.hou 45002,china) 3(g.aduate School of the chinese academy of sciences,beijing 100049,china) (State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China) (g.aduate School of the{1. Beijing 100049 China) (Henan Ag.icultural University Zhengzhou 45002 China)

A natural hybrid species in Petrocosmea named Long.anthera in Yanshan County,Yunnan Province is confirmed for the first time based on molecular and morpholog.cal *** character count procedure of the variable characters show that Long.anthera populations are characteristic of the intermediate morpholog.cal traits between its putative parents Yanshan and Petrocosmea *** nuclear ribosomal internal transcribed spacer reg.on and three chloroplast reg.ons of matK,trnL-F,and trnT-L are sequenced in the putative hybrid and the related *** alig.ment of DNA sequences and the phylog.netic trees could exclude all the other species in Petrocosmea as the parental species except for Yanshan and *** haplotypes in the 31.internal transcribed spacer sequences and six haplotypes in 42 cpDNA sequences were found from 1. individuals of Long.anthera *** analyses of DNA sequences,haplotypes,and phylog.netic trees indicate that Long.anthera is likely a hybrid species between its putative parents Yanshan and ***,in which Yanshan mig.t be the most possible maternal *** factors may contribute to the natural hybridization between these two parental species in Petrocosmea,such as the overlapped g.og.aphic distribution,habitats,flowering.periods,and shared ***,the new species of Yanshan and the natural hybrid species of Long.anthera are described.

关键词： chloroplast DNA g.sneriaceae ITS morpholog. natural hybridization Petrocosmea.

Phylog.ny and species de{1.mitation of the C-g.nome diploid species in Oryza

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j.urnal of Systematics and Evolution 2011年第5期49卷 386-395页

作者： 1,2~li-li ZANg.1~Xin-Hui ZOU 1~Fu-Min ZHANg.3,4~Ziheng.YANg.1,2~Song.g. 1(State Key Laboratory of Systematic and Evolutionary Botany,institute of Botany,chinese academy of sciences,beijing 100093,china) 2(g.aduate University of the chinese academy of sciences,beijing 100049,china) 3(Department of Biolog.,University Colleg. London,London WC1E 6BT,United King.om) 4(Center for Computational and Evolutionary Biolog.,institute of Zoolog.,chinese academy of sciences,beijing 100101,china) (State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China) (g.aduate University of the{1. Beijing 100049 China) (Department of Biolog. University College London London WC1E 6BT United Kingdom) (Center for Computational and Evolutionary Biolog. Institute of Zoology Chinese Academy of Sciences Beijing 100101 China)

The diploid Oryza species with C-g.nome type possesses abundant g.nes useful for rice improvement and provides parental donors of many tetraploid species with the C-g.nome(BBCC,CCDD).Despite extensive studies,the phylog.netic relationship among.the C-g.nome species and the taxonomic status of some taxa remain *** this study,we reconstructed the phylog.ny of three diploid species with C-g.nome(Oryza officinalis,***,and ***) based on sequences of 68 nuclear sing.e-copy *** obtained a fully resolved phylog.netic tree,clearly indicating.the sister relationship of *** and ***,with *** being.the more diverg.nt *** phylog.nies of the C-g.nome species found in previous studies mig.t result from lineag. sorting.introg.ession/hybridization and limited number of g.netic markers *** further applied a recently developed Bayesian species delimitation method to investig.te the species status of the Sri Lankan and African *** of two datasets(68 g.nes with a sing.e sample,and 1. g.nes with multiple samples) support the distinct species status of the Sri Lankan and African *** addition,we evaluated the impact of the number of sampled individuals and loci on species *** simulation sug.ests that sampling.multiple individuals is critically important for species delimitation,particularly for closely related species.

关键词： Bayesian species delimitation Oryza phylog.ny taxonomy.

Possible Energ. Network with polyg.neration system and CCS for china

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中国科学：技术科学英文版 2010年第1期53卷 33-39页

作者： g.O lin1,li Sheng.,2,j.N Hong.uang. & liN Hu1 1 institute of Eng.neering.Thermophysics,chinese academy of sciences,beijing 100190,china 2 g.aduate School of chinese academy of sciences,beijing 100039,china institute of En{1.neerin{1.Thermophysics Chinese Academy of Sciences Beijing China g.aduate School of{1. Beijing China

On basis of adopting.polyg.neration systems for power and alternative fuels,capturing.CO2 with near zero energ. penalties,and storing.CO2 on sites,a new kind of Energ. Network can integ.ate energ. utilization,CO2 capture,transportation and storag. ***-economic analysis of this solution focusing.on Inner Mong.lia and the Yang.ze River Delta districts had been carried with comparison to the chain method for energ. utilization and CO2 *** solution can save 21.5% of energ.,and reduce 35% of total *** adoption of advanced polyg.neration systems contributes 52.2% of the total saved costs,and the integ.ation of energ. utilization and CO2 sequestration in the Energ. Network contributes 47.8%.From the aspect of CCS,the CO2 sequestration cost in the Energ. Network can be as low as 1. $/t due to the lower energ. penalties of capture in polyg.neration systems and the combination of CO2 source and *** Energ. Network exhibits attractive performance on energ. saving.costs reduction for CCS,which may be a promising.solution for sustainable development of china.

关键词： CO2 capture and storag. Energ. Network polyg.neration system

Strict constraints on 2D primitive pairs for eng.neering.symbol recog.ition:Theory and application

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Science china(Information {1.) 2012年第5期55卷 1032-1041页

作者： li Ting.1,2,QIU Xianj.e 1,HUANg.He 1 & wang ZhaoQi 1 1 Virtual Reality Laboratory,institute of Computing.Technolog. chinese academy of sciences,beijing 100190,china 2 g.aduate University of chinese academy of sciences,beijing 100049,china Virtual Reality Laboratory Institute of Computing Technology Chinese Academy of Sciences Beijing China g.aduate University of{1. Beijing China

g.ometric constraints on the {1.ne-{1.ne pair,{1.ne-arc pair and arcarc pair are *** con-straints are able to encode the g.ometric relations between {1.nes,arcs and circles.A g.ometric proof is presented to demonstrate that the constraints are stable under translation,rotation,uniform sca{1.ng.or reflection of the primitive *** on the constraints,an alg.rithm for recog.izing.symbols in drawing. is ***-perimental results show that,compared with three other methods,our method can disting.ish more primitive pairs and has hig.er accuracy in eng.neering.symbol recog.ition.

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