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Secure network coding in the presence of eavesdroppers

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Science china(information Sciences) 2010年第3期53卷 648-658页

作者： LUO MingXing1,2,3, YANG YiXian1,2,3, WANG LiCheng1,2,3 & NIU XinXin1,2,3 1information Security Center, State Key Laboratory of Networking and Switching technology, beijing university of Posts and Telecommunications, beijing 100876, china 2Key Laboratory of Network and information Attack and Defence technology of MOE, beijing university of Posts and Telecommunications, beijing 100876, china 3National Engineering Laboratory for Disaster Backup and Recovery, beijing university of Posts and Telecommunications, beijing 100876, china information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China Key Laboratory of Network and information Attack and Defence technology of MOE Beijing University of Posts and Telecommunications Beijing China National Engineering Laboratory for Disaster Backup and Recovery Beijing University of Posts and Telecommunications Beijing China

Our concern, in the paper, is to construct information-theoretic secure network coding in the presence of eavesdroppers. Based on the generalized attack model and all-or-nothing transformation, the security of network coding in the generalized combination network can be characterized by the network capacity and the min-cut bound of wiretapping set from the source. Furthermore, it can be extended to any directed acyclic networks with single source. Compared with the traditional results, we construct information-theoretic secure network coding without additional encryptions and giving up any capacity.

关键词： all-or-nothing transformation secure network coding eavesdropping

Assessment of the apparent activation energies for gas/solid reactions—carbonate decomposition

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Journal of university of Science and technology beijing 2003年第2期10卷 25-29页

作者： Jianhua Liu and Jiayun ZhangMetallurgical Engineering School, university of Science and technology beijing, beijing 100083, china Metall. Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The guidelines for assessing the apparent activation energies of gas/solidreactions have been proposed based on the experimental results from literatures. In CO_2 free inletgas flow, CaCO_3 decomposition between 950 and 1250 K with thin sample layer could be controlled bythe interfacial chemical reaction with apparent activation energy E = (215+-10) KJ/mol and E=(200+-10) kJ/mol at T = 813 to 1020 K, respectively. With relatively thick sample layer between 793and 1273 K, the CaCO_3 decomposition could be controlled by one or more steps involvingself-cooling, nucleation, intrinsic diffusion and heat transfer of gases, and E could vary between147 and 190 kJ/mol. In CO_2 containing inlet gas flow (5 percent-100 percent of CO_2), E wasdetermined to be varied from 949 to 2897 kJ/mol. For SrCO_3 and BaCO_3 decompositions controlled bythe interfacial chemical reaction, E was (213+-15) kJ/mol (1000-1350K) and (305+-15) kJ/mol(1260-1400 K), respectively

关键词： assessment activation energy decomposition carbonate

Application of mesoscale modeling optimization to development of advanced materials

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Progress in natural Science:Materials International 2004年第8期14卷 8-15页

作者： SONG Xiaoyan(School of Materials Science and Engineering, beijing university of technology, beijing 100022, china) Sch. of Materials Science and Eng. Beijing Univ. of Technology Beijing 100022 China

The rapid development of computer modeling in recent years offers opportunities for materials preparation in a more economic and efficient way. In the present paper, a practicable route for research and development of advanced materials by applying the visual and quantitative modeling technique on the mesoscale is introduced. A 3D simulation model is developed to describe the microstructure evolution during the whole process of deformation, recrystallization and grain growth in a material containing particles. In the light of simulation optimization, the long-term stabilized fine grain structures ideal for high-temperature applications are designed and produced. In addition, the feasibility, reliability and prospects of material development based on mesoscale modeling are discussed.

关键词： mesoscale computer simulation Monte Carlo technique deformation recrystallization grain growth.

Water in peridotite xenoliths from South china

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Science china Earth Sciences 2011年第10期54卷 1511-1522页

作者： WANG Rong 1,2,3 & ZHANG BaoMin 3 1 Faculty of Land resource Engineering, Kunming university of Science and technology, Kunming 650093, china 2 State Key Laboratory for Mineral Deposits Research, Nanjing university, Nanjing 210093, china 3 Faculty of Earth Science, china university of Geosciences, Wuhan 430074, china Faculty of Land resource Engineering Kunming University of Science and Technology Kunming China State Key Laboratory for Mineral Deposits Research Nanjing University Nanjing China Faculty of Earth Science China University of Geosciences Wuhan China

The water contents of nominally anhydrous clinopyroxene （cpx）, orthopyroxene （opx） and olivine （ol） in peridotite xenoliths hosted by Cenozoic basalts from Yingfengling, Zhangchouchun, Fujitian and Lindi, South china, were measured by Micro- FTIR. All cpx and opx grains contained a certain amount of water, which was indicated by the presence of hydroxyls in the crystal structure. The water contents （H20, ppm） of cpx and opx from peridotite xenoliths of the study areas were 293-981, 183-752, 73-586 and 51-423 ppm, and 82-471, 74-571, 53-170 and 9-135 ppm, respectively. No prominent OH absorption bands were detected for any ol grains, indicating that the water contents were below the detection limit （approximately 2 ppm）. The entire rock contents recalculated according to mineral volume proportions were 49-163, 48-168, 21-111 and 8-40 ppm, respectively. Combined with previously reported data describing the water contents of peridotite xenoliths worldwide, the results presented here suggest that water distribution in the continental lithospheric mantle is spatially heterogeneous at a global scale. The lithospheric mantle of South china is much richer in water than that of the North china Craton, and is close to that typical of off-craton localities, such as the Basin and Range Province, and Massif Central.

关键词： FTIR water peridotite xenoliths South china

Prescribing symmetric scalar curvature on S^2

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Chinese Science Bulletin 1999年第6期44卷 514-517页

作者： Jl MinGraduate School, university of Science and technology of china, beijing 100039, china Graduate School University of Science and Technology of China Bajing China

The problem of prescribing scalar curvature in S^2 is discussed, and the solvability of the equation - ΔU + 2-Re^U= 0 on S^2, is given, where R ∈ C^0 (S^2). It is known that there are some obstructions. Some new results are given by seeking a solution of the minimax type. For example, supposing that R is G symmetric and is constant on the set of fixed points on S^2 under G ( where G is a subgroup of O (3)), it is proved that the equation is solvable if and only if R is positive somewhere.

关键词： scalar curvature critical point symmetric function minimax solution transformation group.

Tribological Performance of TiB_2-Ni Composite Coating Deposited by APS

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稀有金属材料与工程 2012年第S1期41卷 481-486页

作者： Zhu Hongbin,Li Hui,Li Zhuoxin beijing university of technology,beijing 100124,china beijing Univ Technol Beijing 100124 Peoples R China

TiB2-Ni composite powders were prepared by pressurized hydrogen reduction cladding with different proportion of *** coatings were then prepared by *** microstructures and the phase composition of the powders as well as the deposited coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The coatings were tested using a ring-on-disc tribometer from ambient temperature to 300°C.A sprayed Cr3C2-NiCr coating was tested as a *** morphologies of the worn surface of the coatings were observed and *** is found that the TiB2-Ni composite coatings present higher friction coefficient than that of the Cr3C2-NiCr coating at room temperature due to the adhesive wear mechanism,whereas the main wear mechanism of Cr3C2-NiCr coating is rupture and ***,at high temperature,the friction coefficient of the TiB2-Ni composite coating decreases as a result of B2O3 solid lubricant,which alleviates the adhesive wear on ***,the TiB2-Ni composite coating greatly reduces the mass loss of the boron cast iron.

关键词： TiB2-Ni composite coating APS wear behavior

Digital forestry research in china

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Science china(Technological Sciences) 2006年第Z1期49卷 1-8页

作者： TANG Shouzheng, TANG Una, Guofan Shao & DAI Limin Research Institute of resource information Techniques, Chinese Academy of Forestry, beijing 100091, china Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, china Departmet of Forestry and natural resources, Purdue university, West Lafayette, IN 47907, USA Graduate university, Chinese Academy of Sciences, beijing 100101, china Research Institute of resource information Techniques Chinese Academy of Forestry Beijing China Institute of Applied Ecology Chinese Academy of Sciences Shenyang China Graduate university Chinese Academy of Sciences Beijing China Department of Forestry and natural resources Purdue University West Lafayette USA

Digital Forestry as a concept was developed after the Digital Earth program. The Chinese scientists were not only among the pioneers who first proposed the concept of Digital Forestry, but also contributed a lot to the development of Digital Forestry. Digital Forestry is a digital framework to maintain forest planting, management, using, and protect. The synergetic use of computationally-intensive quantitative methods together with information technologies is the most important foundation for the development of Digital Forestry. Under this situation, the experience of Digital Forestry development in china is relatively rich. A number of academicians, scholars, and professional administrators were involved in discussing the Digital Forestry Construction Scheme. The Project of Digital Forestry Practicability approved by the State Forestry Administration is a major instance in developing Digital Forestry standard and key techniques. By introducing a case study of Digital Forestry, this paper reviews the concept of Digital Forestry, the way turning traditional forestry into Digital Forestry, and the future development of Digital Forestry.

关键词： Digital Forest, Digital Earth, Digital Forestry standard, Digital Forestry techniques.

Restoration of eroded stratal thickness in key periods of tectonic change in a multi-stage superimposed Tarim Basin in china

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Journal of Palaeogeography 2012年第2期1卷 149-171页

作者： Liu Hao1, Wang Yingmin2 1. School of Marine Sciences, china university of Geosciences (beijing), beijing 100083, china 2. School of Geosciences, china university of petroleum (beijing), beijing 102249, china School of Marine Sciences China University of Geosciences (Beijing) Beijing 100083 China School of Geosciences China University of Petroleum (Beijing) Beijing 102249 China

With an area of 56×104km2, the Tarim Basin is the largest inland basin in china and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data from 22 regional seismic profiles and 40 drilling wells, 15 important first-order and second-order regional unconformities were *** all the main unconformities are superimposed unconfomities. Since the Cambrian, 5 key periods of tectonic change have occurred during the evolution of the Tarim Basin. The total eroded stratal thickness of the above-mentioned unconformities was calculated by using the method of virtual extrapolation of seismic reflection. The results indicate that the total eroded stratal thickness of different periods is quite different in different locations of the basin. Taking the Upper-Middle Ordovician as an example, its thickness restoration of eroded strata was calculated into individual stages i.e. its thickness restoration of eroded strata was calculated to different tectonic periods. Otherwise, as for the specific period of tectonic change, the underlying strata were, respectively eroded and thus the thickness restoration of eroded strata was calculated into individual intervals. Taking the Early Hercynian period as an example, the eroded stratal thickness was calculated into individual intervals to calculate the ratio of intervals of various ages occupying the total eroded thickness. The results show that for the same stratum, its degree of erosion is quite different in different periods and at different locations, due to the varying influence of tectonic movement. The unconformities of some key periods of tectonic change have different controls on the degree of erosion and the eroded range of the individual period of the underlying strata which are the typical characteristics of multi-stage superimposition of unconformities in the Tarim Basin.

关键词： Tarim Basin extrapolation of virtual surface key period of tectonic change superimposed unconformity restoration of eroded stratal thickness

Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 672-679页

作者： MA Jun 1,2, TANG Jun 2 , ZHANG AiHua 3 & JIA Ya 2 1 Department of Physics, Lanzhou university of technology, Lanzhou 730050, china 2 Department of Physics, Central china Normal university, Wuhan 430079, china 3 College of Electrical and information Engineering, Lanzhou university of technology, Lanzhou 730050, china Department of Physics Lanzhou University of Technology Lanzhou China Department of Physics Central China Normal University Wuhan China College of Electrical and information Engineering Lanzhou University of Technology Lanzhou China

The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.

关键词： spiral wave factor of synchronization breakup multiplicative noise robustness