检索结果-南通市图书馆

A New Localization Scheme with Statistical Estimation against Wormhole Attack in Wireless Sensor Networks

在线全文

学校读者我要写书评

暂无评论

China Communications 2010年第5期7卷 57-69页

作者： niu Yanchao Gao Deyun Chen ping Zhang Sidong Zhang Hongke National Engineering Laboratory for Next Generation Internet Interconnection Devices Beijing Jiaotong University Beijing 100044 P. R. China TEDA College Nankai University Tianjin 300457 P. R. China

Wormhole attack is one of the most devastating threats for range-free localization in wireless sensor networks. In this paper, we evaluate three statistical estimation methods with the same network model and geographic information obtailaed by the DV-Hop algorithm. We analyze the limits of Minimum Mean Square Estimate （MMSE）, Least Median of Squares （LMS） and Enhanced greedy At- tack-Resistant MMSE （EARMMSE） and propose an improved EARMMSE with the hop-distance relationship, named EARMMSE＋. Simulation results illustrate the performance of MMSE, LMS and EARMMSE＋ with different anchor fraction, the length of wormhole link and the average local neighborhood and show that EARMMSE＋ outperforms MMSE and LMS.

关键词： wireless sensor network range-free localization wormhole attack DV-Hop statistical estimation

Synthesis and Crystal Structure of a Novel 1D Chain-like Organic Inorganic Hybrid Rare Earth Derivative of Polyoxometalate: H_(0.5)[Sm(H_2O)_6]_(0.25)[Sm(H_2O)_5]_(0.25){[Sm(H_2O)_7][Sm(H_2O)_2-(DMSO)][SiW_(11)O_(39)]}·4.5H_2O

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2005年第12期16卷 1655-1658页

作者： Jun Wei ZHAO Jing ping WANG Jing Yang niu School of Chemistry and Chemical Engineering Henan University Kaifeng 475001

A 1D chain-like organic-inorganic hybrid rare earth derivative of polyoxometalate H0.5[Sm（H2O）6]0.25[Sm（H2O）5]0.25{[Sm（H2O）7][Sm（H2O）2（DMSO）][SiW11O39]}·4.5H2O has been firstly synthesized by reaction of α-K8SiW11O39.13H2O, HClO4, Sm2O3 with dimethyl sulfoxide （DMSO） and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. The neighboring polyanionic units {[Sm（H2O）7][Sm（H2O）2（DMSO）][SiWHO39]}^2- are bridged together to a 1D chain structure by means of [Sm（H2O）2（DMSO）]^3＋ ion.

关键词： Silicotungstic acid polyoxometalate mono-vacant Keggin structure rare earth ions

High Precision Prediction of Rolling Force Based on Fuzzy and Nerve Method for Cold Tandem Mill

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2008年第2期15卷 23-27页

作者： JIA Chun-yu SHAN Xiu-ying niu Zhao-ping College of Mechanical Engineering Yanshan University Qinhuangdao 066004 Hebei China

The rolling force model for cold tandem mill was put forward by using the Elman dynamic recursive network method,based on the actual measured ***,a good assumption is put forward,which brings a full universe of discourse self-adjusting factor fuzzy control,closed-loop adjusting,based on error feedback and expertise into a rolling force prediction model,to modify prediction outputs and improve prediction precision and *** simulated results indicate that the method is highly effective and the prediction precision is better than that of the traditional *** relative error is less than ±4%,so the prediction is high precise for the cold tandem mill.

关键词： Elman dynamic recursive network fuzzy control cold tandem mill rolling force prediction

An Unprecedented 1D Zigzag Chain Alkaline Earth Metal Derivative {[Ba(DMF)_3(H_2O)_2][Ba(DMF)_4]_2(P_2W_(18)O_(62))}_n Containing Dawson Heteropolyanion

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2006年第6期17卷 817-820页

作者： Jing ping WANG Jian Ru MA Jing Yang niu School of Chemistry and Chemical Engineering Henan University Kaifeng 475001

An unprecedented 1D zigzag chain alkaline earth metal derivative, {[Ba（DMF）3 （H20）2][Ba（DMF）412（P2W18O62）}n, （DMF=N, N-dimethyl formamide） containing Dawson hetero- polyanion has been successfully synthesized and characterized by X-ray crystallography. Two barium cations bridged by three DMF ligands in parallel combination with the Dawson-type heteropolyanion [P2W18O62]^6- and then the resulting subunits {[Ba（DMF）4]2（P2WlsO62）}^2＋ are alternately linked together via another [Ba（DMF）3（H2O）2]^2＋ ions, constructing a 1D zigzag chain architecture.

关键词： Polyoxometalate crystal structure Dawson structure.

Computational analysis of fluid-structure interaction in case of fish swimming in the vortex street

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第4期33卷 747-762页

作者： Lang Yan Xing-hua Chang Nian-hua Wang run-yu Tian Lai-ping Zhang Wei Liu College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073China Unmanned Systems Research Center National Innovation Institute of Defense TechnologyBeijing100071China China Aerodynamics Research and Development Center State Key Laboratory of AerodynamicsMianyang621000China Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang621000China

The fluid-structure interaction (FSI) in case of fish swimming in the vortex street is investigated by numerical simulations. The vortex street is generated by a D-section cylinder. A 2-D fish model is placed on the downstream centerline of the bluff cylinder at a distance of 4 diameters away from the center of the cylinder. To simulate the fish body undulation and movement, the moving mesh is generated by a coupling approach based on the radial basis function and the overset grid technology. The Navier-Stokes equation in the arbitrary Lagrangian-Eulerian form is solved by coupling with the kinematics equation. Three cases are investigated: in a stationary position without deformation, a passive locomotion without deformation, and an active deformation based on the Kármán gait model. The results indicate that the fish body is acted by an alternating force and moment when it is located in the centerline of the vortex street. Furthermore, the fish could extract sufficient kinetic energy to overcome the drag under suitable conditions even when it keeps rigid and out of the suction zone. When the fish body undulates based on the Kármán gait model, the interaction is evidently shown between the fish body and the vortices. The theoretical analysis demonstrates that the lateral force and the moment acting on the fish body vary in a cosine formula, with the lateral translation and the body rotation as a result. This study focuses on the behavior of the fish body in the bluff cylinder wake and reproduces some phenomena observed in the experiments. Besides, the Kármán gait model is also theoretically analyzed, for the further exploration of the FSI mechanism in case of fish swimming.

关键词： Computational analysis fluid-structure interaction(FSI) Kármán gait vortex street passive locomotion fish swimming

A Novel Ni-capped Silverton-type Complex: H_4{[Ni(H_2O)_3]_2[CeMo_(12)O_(42)]}·13.5H_2O

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2006年第2期25卷 204-208页

作者： WANG Jing-ping SHEN Yue GUO Gui-Ling niu Jing-Yang School of Chemistry and Chemical Engineering Henan University Kaifeng 475001 China

A novel Ni-capped complex H4{[Ni（H2O）3]2[CeMo12O42] }· 13.5H2O has been synthesized, which is the first Silverton-type anion capped with two Ni units via three terminal oxygen atoms. Crystallographic data for the title compound： Trigonal, space group R-3, a = 13.0950（19）, b = 13.0950（19）, c = 33.029（7） A, α = β= γ = 58.727（17）A °, V = 4905.1（14） A °^3, Z = 3, Mr= 2437.17, Dc = 2.475 g/cm^3, F（000） = 3462, T = 293（2） K, μ（MoKa） = 3.564 mm^-1, Rt = 0.0369, wR2 = 0.0905 and GOF= 1.079 for 151 parameters and 1963 reflections with I 〉 2σ（I） in the range of 1.85≤θ≤25.50°.

关键词： crystal structure Silverton-type Ni-capped

A survey on the network models applied in the industrial network optimization

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第2期67卷 85-103页

作者： Chao DONG Xiaoxiong XIONG Qiulin XUE Zhengzhen ZHANG Kai niu ping ZHANG Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Smart City College Beijing Union University

Network architecture design is critical for optimizing industrial networks. Network architectures can be classified into small-scale networks and large-scale networks based on scale. Graph theory is an efficient mathematical tool for network topology modeling. For small-scale networks, their structure often has regular topology. For large-scale ones, the current body of work mainly focuses on random characteristics of network nodes and edges. Recently, widely used models include random networks, small-world networks,and scale-free networks. In this study, starting from the scale of the network, network modeling methods based on graph theory as well as their industrial applications, are summarized and analyzed. Moreover, a novel network performance metric, called system entropy, is proposed. From the perspective of mathematical properties, an analysis of its non-negativity and concavity is performed. The advantage of system entropy is that it can cover the existing regular networks, random networks, small-world networks, and scale-free networks, and has strong generality. The simulation results reveal that this proposed metric can achieve the comparison of various industrial networks under different models.

关键词： industrial network small-scale network large-scale network graph theory system entropy

A Reliable Neighbor-Based Method for Identifying Essential Proteins by Integrating Gene Expressions, Orthology,and Subcellular Localization Information

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2016年第6期21卷 668-677页

作者： Min Li Zhibei niu Xiaopei Chen ping Zhong Fangxiang Wu Yi Pan the School of Information Science and Engineering Central South University the Department of Mechanical Engineering and Division of Biomedical Engineering University of Saskatchewan the Department of Computer Science Georgia State University

Essential proteins are those necessary for the survival or reproduction of species and discovering such essential proteins is fundamental for understanding the minimal requirements for cellular life, which is also meaningful to the disease study and drug design. With the development of high-throughput techniques, a large number of Protein-Protein Interactions（PPIs） can be used to identify essential proteins at the network level. Up to now, though a series of network-based computational methods have been proposed, it is still a challenge to improve the prediction precision as the high false positives in PPI networks. In this paper, we propose a new method GOS to identify essential proteins by integrating the Gene expressions, Orthology, and Subcellular localization *** gene expressions and subcellular localization information are used to determine whether a neighbor in the PPI network is reliable. Only reliable neighbors are considered when we analyze the topological characteristics of a protein in a PPI network. We also analyze the orthologous attributes of each protein to reflect its conservative features, and use a random walk model to integrate a protein＇s topological characteristics and its orthology. The experimental results on the yeast PPI network show that the proposed method GOS outperforms the ten existing methods DC, BC, CC, SC, EC, IC, NC, Pe C, ION, and CSC.

关键词： essential protein reliable neighbors GOS orthology subcellular localization information

A novel hole cold-expansion method and its effect on surface integrity of nickel-based superalloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第24期59卷 129-137页

作者： XianCao ping ZhangShuang Liu Xue-Lin Lei run-Zi Wang Xian-Cheng Zhang Shan-Tung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China

Preferred surface integrity around the hole wall is one of the key parameters to ensure the optimized performance of hole components for nickel-based *** novel hole cold expansion technique introduced in this work involves the laser texturing process(LTP)followed by the Hertz contact rotary expansion process(HCREP),where the cylindrical sleeve is the critical component connecting the abovementioned two *** purpose of LTP is to obtain the most optimized strengthened cylindrical sleeve surface,preparing for the following ***,the HCREP acts on the nickel-based hole components by the rotary extruding movements of the strengthened sleeve and conical mandrel *** compared to the as-received GH4169 material,the surface integrity characterization for the strengthened hole shows that a plastic deformation layer with finer grains,higher micro-hardness,deeper compressive residual stress(CRS)distribution and lower surface roughness is formed at the hole *** addition,transmission electron microscope(TEM)observations reveal the microstructure evolution mechanism in the strengthened *** refinement near the hole wall is regarded as the fundamental reason for improving the surface integrity,where the aggregated dislocations and recombined dislocation walls can be clearly observed.

关键词： Cold expansion process Laser texturing process Surface integrity Microstructure evolution