检索结果-南通市图书馆

Full Diversity Reception Based on Dempster-Shafer Theory for Network Coding with Multiple-Antennas Relay

在线全文

学校读者我要写书评

暂无评论

China Communications 2015年第10期12卷 76-90页

作者： SUN yanhua YANG Yi LI Yonghua zhang yanhua College of Electronic Information and Control Engineering Beijing University of Technology School of Information Engineering Beijing University of Posts and Telecommunications

In this paper,a two-way relay system which achieves bi-directional communication via a multiple-antenna relay in two time slots is *** the multiple access(MA) phase,the novel receive schemes based on Dempster-Shafer(D-S) evidence theory are proposed at the relay *** of traditional linear detection,the first proposed MIMO-DS NC scheme adopts D-S evidence theory to detect the signals of each source node before mapping them into network-coded ***,different from traditional physical-layer network coding(PNC) based on virtual MIMO model,the further proposed MIMO-DS PNC comes from the vector space perspective and combines PNC mapping with D-S theory to obtain network-coded signal without estimating each source node signal.D-S theory can appropriately characterize uncertainty and make full use of multiple evidence source information by Dempster's combination rule to obtain reliable *** the broadcast(BC) phase,the space-time coding(STC) and antenna selection(AS) schemes are adopted to achieve transmit *** results reveal that the STC and AS schemes both achieve full transmit diversity in the BC phase and the proposed MIMO-DS NC/PNC schemes obtain better end-to-end BER performance and throughputs compared with traditional schemes with a little complexity increasing and no matter which scheme is adopted in the BC phase,MIMO-DS PNC always achieves full end-to-end diversity gain as MIMO-ML NC but with a lower complexity and its throughput approaches the throughput of MIMO-ML NC in high SNR regime.

关键词： network coding MIMO-DS NC/PNC Dempster-Shafer evidence theory twoway multiple antennas relay system

Geometric dilution of precision for GPS single-point positioning based on four satellites

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第5期19卷 1058-1062,F0003页

作者： Wang Huihui Zhan Xingqun zhang yanhua Inst. of Aerospace Science & Technology Shanghai Jiaotong Univ. Shanghai 200240 P. R. China

To improve the positioning accuracy in GPS point positioning, the geometric dilution of precision （GDOP） including HDOP, VDOP, TDOP, PDOP is commonly considered. The properties of the DOP for the GPS satellite navigation system are studied and the coordinate system is improved in order to decrease the amount of variables. In the end, by simulation and discussing the results, the corresponding conclusions are presented.

关键词： GPS dilution of precision GDOP navigation simulation.

Efficient Algorithm for K-Barrier Coverage Based on Integer Linear Programming

在线全文

学校读者我要写书评

暂无评论

China Communications 2016年第7期13卷 16-23页

作者： yanhua zhang Xingming Sun Baowei Wang Nanjing University of Information Science&Technology NanjingChina Jiangsu Lightning Protection Center NanjingChina

Barrier coverage of wireless sensor networks is an important issue in the detection of intruders who are attempting to cross a region of ***,in certain applications,barrier coverage cannot be satisfied after random *** this paper,we study how mobile sensors can be efficiently relocated to achieve k-barrier *** particular,two problems are studied:relocation of sensors with minimum number of mobile sensors and formation of k-barrier coverage with minimum energy *** two problems were formulated as 0–1 integer linear programming(ILP).The formulation is computationally intractable because of integrality and complicated ***,we relax the integrality and complicated constraints of the formulation and construct a special model known as RELAX-RSMN with a totally unimodular constraint coefficient matrix to solve the relaxed 0–1 ILP rapidly through linear *** analysis and simulation were performed to verify the effectiveness of our approach.

关键词： k-barrier coverage linear programming wireless sensor networks

Transferring in control plane for 5G heterogeneous networks

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2019年第3期25卷 271-276页

作者： Bi Ruiqi Yang Ruizhe Sun yanhua Wang Zhuwei zhang yanhua Department of Information Beijing University of TechnologyBeijing 100124P.R.China Beijing Laboratory of Advanced Information Networks Beijing 100124P.R.China

The heterogeneous network with the separation of the control plane and user plane(C/U) is an evolutionary approach to the fifth generation(5 G) to achieve high system coverage and capacity. To minimize signaling load of the core network when there is a macro base station(BS) failure in the control plane, a scheme of transferring the control of small cells under the coverage of the failure macro BS to the neighbor macro BSs is proposed. The average handover rates between small cells related to user mobilities, the extended coverage of the neighboring macro BSs under the constraint of transmitting power and the load balance index of the system are analyzed, based on which the formula of maximizing the handovers processed by macro BSs is constructed and further solved by the convex optimization methods. Simulation results indicate that the proposed scheme can effectively increase the total handovers processed by the macro BSs and thus reduce the signaling load of the core network.

关键词： C/U separation 5G control plane optimization signaling load

Study on conditions of internally carried air-launched launch vehicles based on the virtual prototype technology

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2014年第2期20卷 166-172页

作者：张久星 Xu Haojun zhang Dengcheng zhang yanhua Engineering Institute Air Force Engineering University

A method based on the virtual prototype technology simulating the separation of a launch vehicle from its aircraft in the aircraft wake was proposed based on the internally carried air-launched launch vehicle *** this method,the full-scale model of the aircraft,the vehicle and the parachute are ***,they are imported into the ADAMS software,constraint solutions and driving forces are then added for visual dynamic *** unsteady aerodynamic forces of the vehicle in the aircraft wake are calculated by CFD and the moving grid *** forces generated by the parachute can be derived from the Kirchhoff motion *** comparing and analyzing the simulation results under different launch conditions,it has been proven that this method simulates the separation of a launch vehicle from the aircraft in the aircraft wake *** provides the foundation for the aggregate project of internally carried air-launch vehicles,and offers a new referenced method for multi-body dynamic simulation.

关键词： air launch flight dynamics virtual prototype automatic dynamic analysis of me- chanical system (ADAMS) parachute

Microbial diversity in the saline-alkali soil of a coastal Tamarix chinensis woodland at Bohai Bay, China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2016年第2期8卷 284-292页

作者： LIU Wanqiu zhang Wei LIU Guangxiu zhang yanhua zhang Gaosen Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China Key Laboratory of Extreme Environmental Microbial Resources and Engineering Gansu ProvinceLanzhou 730000China Ocean and Fishery Bureau of Changyi Changyi 261300China

Soil salinization or alkalization is a form of soil desertification. Coastal saline-alkali soil represents a type of desert and a key system in the network of ecosystems at the continent-ocean interface. Tamarix chinensis is a drought-tolerant plant that is widely distributed in the coastal saline-alkali soil of Bohai Bay, China. In this study, we used 454 pyrosequencing techniques to investigate the characteristics and distribution of the microbial diversity in coastal saline-alkali soil of the T. chinensis woodland at Bohai Bay. A total of 20,315 sequences were obtained, representing 19 known bacterial phyla and a large proportion of unclassified bacteria at the phylum level. Proteobacteria, Acidobacteria and Actinobacteria were the predominant phyla. The coverage of T. chinensis affected the microbial composition. At the phylum level, the relative abundance of y-Proteobacteria and Bacteroidetes decreased whereas Actinobacteria increased with the increasing coverage of T. chinensis. At the genus level, the proportions of Steroidobacter, Lechevalieria, Gp3 and Gp4 decreased with the increase of the vegetation coverage whereas the proportion of Nocardioides increased. A cluster analysis showed that the existing T. chinensis changed the niches for the microorganisms in the coastal saline-alkali soil, which caused changes in the microbial community. The analysis also distinguished the microbial community structure of the marginal area from those of the dense area and sparse area. Furthermore, the results also indicated that the distance to the seashore line could also affect certain groups of soil bacteria in this coastal saline-alkali soil, such as the family Cryomorphaceae and class Flavobacteria, whose population decreased as the distance increased. In addition, the seawater and temperature could be the driving factors that affected the changes.

关键词： coastal saline-alkali soil Tamarix chinensis bacteria pyrosequencing

Study of nonlinear filter methods: particle filter

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2006年第1期17卷 1-5页

作者： zhang Weiming Du Gang Zhong Shan zhang yanhua Dept. of Information Measurement Technology and Instruments Shanghai Jiaotong Univ. Shanghai 200030 P.R. China The Second Academy China Aerospace Science and Industry Corporation Beijing 100854 P.R. China

Extended Kalman filter （EKF） is one of the most widely used methods for nonlinear system estimation. A new filtering algorithm, called particle filtering （PF） is introduced. PF can yield better performance than that of EKF, because PF does not involve the linearization approximating to nonlinear systems, that is required by the EKF. PF has been shown to be a superior alternative to the EKF in a variety of applications. The base idea of PF is the approximation of relevant probabifity distributions using the concepts of sequential importance sampling and approximation of probability distributions using a set of discrete random samples with associated weights. PF methods still need to be improved in the aspects of accuracy and calculating speed.

关键词： nonlinear extended Kalman filter particle filter Monte Carlo methods.

Responses of radial growth, wood density and fiber traits to planting space in poplar plantations at a lowland site

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2022年第3期33卷 963-976页

作者： yanhua zhang Shengzuo Fang Ye Tian Linlin Wang Yi Lv College of Forestry Nanjing Forestry UniversityNanjing210037People’s Republic of China Co-Innovation Center for Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjing210037People’s Republic of China

Poplar is raw material for various panel, paper and fiber products. The 12 sample trees of clone Nanlin-895 from four spacings were destructively harvested after thirteen growing seasons to assess the influence of spacing on radial growth and wood properties. Spacing significantly affected tree-ring width and wood basic density (p < 0.05) but not fiber traits. The highest diameter and wood basic density at breast height (1.3 m) was in 6 m × 6 m and 3 m × 8 m spacings, respectively. However, no significant differences in tree-ring width, wood basic density and fiber traits were observed among the four sampling directions in discs taken at 1.3 m for each spacing. Growth rings from the pith and tree heights had significant effects on wood basic density and fiber anatomical characteristics, highlighting obvious temporal-spatial variations. Pearson correlation analysis showed a significantly negative relationship of tree-ring width to wood basic density, fiber length and fiber width, but a significantly positive relationship to hemicellulose. There was no relationship with cellulose and lignin contents. Based on a comprehensive assessment by the TOPSIS method, the 6 m × 6 m spacing is recommended for producing wood fiber at similar sites in the future.

关键词： Planting density Growth ring Fiber morphology Chemical composition Temporal-spatial variation

Verifier-local revocation group signatures with backward unlinkability from lattices

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2022年第6期23卷 876-892页

作者： yanhua zhang Ximeng LIU Yupu HU Yong GAN Huiwen JIA College of Computer and Communication Engineering Zhengzhou University of Light IndustryZhengzhou 450001China College of Mathematics and Computer Science Fuzhou UniversityFuzhou 350108China Stale Key Laboratory of Integrated Service Networks Xidian UniversityXi’an 710071China College of Information Engineering Zhengzhou University of TechnologyZhengzhou 450044China School of Mathematics and Information Science Guangzhou UniversityGuangzhou 510006China

For group signature(GS)supporting membership revocation,verifier-local revocation(VLR)mechanism seems to be a more flexible choice,because it requires only that verifiers download up-to-date revocation information for signature verification,and the signers are not *** a post-quantum secure cryptographic counterpart of classical number-theoretic cryptographic constructions,the first lattice-based VLR group signature(VLR-GS)was introduced by Langlois et al.(2014).However,none of the contemporary lattice-based VLR-GS schemes provide backward unlinkability(BU),which is an important property to ensure that previously issued signatures remain anonymous and unlinkable even after the corresponding signer(i.e.,member)is *** this study,we introduce the first lattice-based VLR-GS scheme with BU security(VLR-GS-BU),and thus resolve a prominent open problem posed by previous *** new scheme enjoys an O(log N)factor saving for bit-sizes of the group public-key(GPK)and the member’s signing secret-key,and it is free of any public-key *** the random oracle model,our scheme is proven secure under two well-known hardness assumptions of the short integer solution(SIS)problem and learning with errors(LWE)problem.

关键词： Group signature Lattice-based cryptography Verifier-local revocation Backward unlikability Short integer solution