检索结果-南通市图书馆

Distance Between α-Orientations of Plane Graphs by Facial Cycle Reversals

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2019年第4期35卷 569-576页

作者： wei juan zhang Jian Guo QIAN Fu Ji zhang School of Mathematical Sciences Xiamen University School of Mathematical Sciences Xinjiang Normal University

Cycle reversal had been shown as a powerful method to deal with the relation among orientations of a graph since it preserves the out-degree of each vertex and the connectivity of the orientations. A facial cycle reversal on an orientation of a plane graph is an operation that reverses all the directions of the edges of a directed facial cycle. An orientation of a graph is called an α-orientation if each vertex admits a prescribed out-degree. In this paper, we give an explicit formula for the minimum number of the facial cycle reversals needed to transform one α-orientation into another for plane graphs.

关键词： α-Orientation facial cycle reversal distance plane graph

Distributions of Neutron Exposures in AGB Stars and the Galaxy

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 224-234页

作者： Wen-Yuan Cui Feng-Hua zhang wei-juan zhang Lu zhang Bo zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Department of Physics Hebei Normal University Shijiazhuang 050016 Department of Modern Physics University of Science and Technology of China Hefei 230026 Graduate School of Chinese Academy of Sciences Bejing 100049

Based on the s-process nucleosynthesis model with the 13C（α, n）16O reaction occurring under radiative conditions in the interpulse phases, we investigate the characteristics of the distribution of neutron exposure in low-mass Asymptotic Giant Branch （AGB） stars. We introduce a new concept, the distribution of neutron exposures of the Galaxy （NEG）, to study the chemical evolution characteristics of the Galaxy for s-process elements. Using a chemical evolution model of the Galaxy, we develop a model for the NEG and obtain the evolution results of the NEG in different epochs. The present results appear to reasonably reproduce the distribution of neutron exposures of the solar system （hereafter NES）. The main component and the strong component in the NES are built up in different epochs. The strong component of the s-process is mainly synthesised in the low-mass and metal-poor AGB stars, and the main component is produced by the s-process in the low-mass AGB stars with higher metallicities.

关键词： Galaxy evolution- stars AGB and post-AGB- stars abundances

Cubic vertex-transitive non-Cayley graphs of order 12p

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2018年第6期61卷 1153-1162页

作者： wei-juan zhang Yan-Quan Feng Jin-Xin Zhou Department of Mathematics Beijing Jiaotong University Beijing 100044 China

A graph is said to be vertex-transitive non-Cayley if its full automorphism group acts transitively on its vertices and contains no subgroups acting regularly on its vertices. In this paper, a complete classification of cubic vertex-transitive non-Cayley graphs of order 12 p, where p is a prime, is given. As a result, there are 11 sporadic and one infinite family of such graphs, of which the sporadic ones occur when p equals 5, 7 or 17, and the infinite family exists if and only if p ≡ 1(mod 4), and in this family there is a unique graph for a given order.

关键词： Cayley graphs vertex-transitive graphs automorphism groups

Privacy-Preserving Trust Negotiation with Hidden Credentials and Hidden Policies in a Multi-Party Environment

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2008年第5期13卷 553-556页

作者： GUO Shanqing wei juan zhang Chunhua XU Qiuliang School of Computer Science and Technology ShandongUniversity Jinan 250101 Shandong China

Until now, there are numerous protocols that can achieve privacy-preserving trust negotiation between two parties involved, but there is no effective privacy-preserving trust negotiation schemes proposed between multi-users. In this paper, a privacy-preserving trust negotiation scheme with multi-parties is proposed, which can protect their credentials and access control policies during the procedure for establishing the trust between multi-strangers, and its privacy-preserving ability also is proved. These works extend the trust negotiation mechanism to multi-users, which can be thought as a substantial extension of the state-of-the-art in privacy-preserving trust negotiations between two parties involved.

关键词： trust negotiation credential policy privacy-preserving

Fully distributed dynamic event-triggered formation-containment tracking for multiagent systems with multiple types of disturbances

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第1期67卷 168-186页

作者： weihua LI Huaguang zhang juan zhang Rui WANG College of Information Science and Engineering Northeastern University State Key Laboratory of Synthetical Automation for Process Industries Northeastern University

This paper is dedicated to addressing the time-varying output formation-containment tracking(TVOFCT) problem for heterogeneous linear multiagent systems(MASs) with multiple types of disturbances under directed communication *** agents are divided into tracking leaders,formation leaders,and *** the output space,the formation leaders are required to form an expected geometric formation while tracking the tracking leader,and the followers are required to enter the convex hull spanned by formation ***,a disturbance observer is designed to observe the disturbance with deterministic ***,by combining adaptive technology with event-triggered technology,an independent fully distributed dynamic event-triggered(FDDET) compensator is designed to estimate the state of the tracking *** main advantages of this compensator lie in the following three aspects:(1) the adaptive weight does not increase unboundedly;(2) the interval time between events is expanded;(3) the design does not rely on any global *** to the design of this compensator,an independent FDDET convex hull observer is further designed to observe the convex hull spanned by formation ***,based on the designed disturbance observer,compensator,and convex hull observer,the adaptive disturbance rejection control input which can make the MASs achieve TVOFCT is ***,a numerical simulation is provided to clearly verify the validity of the theoretical results.

关键词： formation-containment tracking disturbance rejection multiagent systems fully distributed control dynamic event-triggered control

Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： TIAN Jing zhang wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

Elite Dung Beetle Optimization Algorithm for Multi-UAV Cooperative Search in Mountainous Environments

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第4期21卷 1677-1694页

作者： Xiaoyong zhang wei Yue The College of Marine Electrical Engineering Dalian Maritime UniversityDalian116026China

This paper aims to address the problem of multi-UAV cooperative search for multiple targets in a mountainous environment,considering the constraints of UAV dynamics and prior environmental ***,using the target probability distribution map,two strategies of information fusion and information diffusion are employed to solve the problem of environmental information inconsistency caused by different UAVs searching different areas,thereby improving the coordination of UAV ***,the task region is decomposed into several high-value sub-regions by using data clustering *** on this,a hierarchical search strategy is proposed,which allows precise or rough search in different probability areas by adjusting the altitude of the aircraft,thereby improving the search ***,the Elite Dung Beetle Optimization Algorithm(EDBOA)is proposed based on bionics by accurately simulating the social behavior of dung beetles to plan paths that satisfy the UAV dynamics constraints and adapt to the mountainous terrain,where the mountain is considered as an obstacle to be ***,the objective function for path optimization is formulated by considering factors such as coverage within the task region,smoothness of the search path,and path *** effectiveness and superiority of the proposed schemes are verified by the simulation.

关键词： Mountainous environment Multi-UAV cooperative search Environment information consistency Elite dung beetle optimization algorithm(EDBOA) Path planning

Inter-well internal resonance analysis of rectangular asymmetric cross-ply bistable composite laminated cantilever shell under transverse foundation excitation

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

Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1353-1370页

作者： Lele REN wei zhang Yufei zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanics Guangxi UniversityNanning 530004China Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical EngineeringBeijing University of TechnologyBeijing 100124China

The chaotic dynamic snap-through and complex nonlinear vibrations are investigated in a rectangular asymmetric cross-ply bistable composite laminated cantilever shell,in cases of 1:2 inter-well internal resonance and primary *** transverse foundation excitation is applied to the fixed end of the structure,and the other end is in a free *** first-order approximate multiple scales method is employed to perform the perturbation analysis on the dimensionless two-degree-of-freedom ordinary differential motion control *** four-dimensional averaged equations are derived in both polar and rectangular coordinate *** from the obtained frequency-amplitude and force-amplitude response curves,a detailed analysis is conducted to examine the impacts of excitation amplitude,damping coefficient,and tuning parameter on the nonlinear internal resonance characteristics of the *** nonlinear softening characteristic is exhibited in the upper stable-state,while the lower stable-state demonstrates the softening and linearity *** simulation is carried out using the fourth-order Runge-Kutta method,and a series of nonlinear response curves are *** the excitation amplitude further elucidates the global bifurcation and chaotic dynamic snap-through characteristics of the bistable cantilever shell.

关键词： bistable composite laminated cantilever shell inter-well internal resonance primary resonance chaotic dynamic snap-through complex nonlinear vibration

Proximal Femur Bionic Nail (PFBN): A Panacea for Unstable Intertrochanteric Femur Fracture

在线全文

学校读者我要写书评

暂无评论

Engineering 2024年第6期37卷 152-158页

作者： Kaixuan zhang wei Chen Yingze zhang School of Medicine Nankai UniversityTianjin 300071China Department of Orthopedic Surgery of Hebei Province The Third Hospital of Hebei Medical UniversityShijiazhuang 050051China Key Laboratory of Biomechanics of Hebei Province Orthopaedic Research Institute of Hebei ProvinceShijiazhuang 050051China National Health Commission(NHC)Key Laboratory of Intelligent Orthopeadic Equipment The Third Hospital of Hebei Medical UniversityShijiazhuang 050051China Chinese Academy of Engineering Beijing 100088China

With the aging population,intertrochanteric femur fracture in the elderly has become one of the most serious public health issues and a hot topic of research in trauma *** to the limitations of internal fixation techniques and the insufficient mechanical design of nails,the occurrence of complications delays patient recovery after surgical *** of a proximal femur bionic nail(PFBN)based on zhang’s N triangle theory provides triangular supporting fixation,which dramatically decreases the occurrence of complications and has been widely used for clinical treatment of unstable intertrochanteric femur fracture *** this work,we developed an equivalent biomechanical model to analyze improvement in bone remodeling of unstable intertrochanteric femur fracture through PFBN *** results show that compared with proximal femoral nail antirotation(PFNA)and InterTan,PFBN can dramatically decrease the maximum strain in the proximal *** on Frost’s mechanostat theory,the local mechanical environment in the proximal femur can be regulated into the medium overload region by using a PFBN,which may render the proximal femur in a state of physiological overload,favoring post-operative recovery of intertrochanteric femur fracture in the *** work shows that PFBN may constitute a panacea for unstable intertrochanteric femur fracture and provides insights into improving methods of internal fixation.

关键词： Intertrochanteric femur fracture Internal fixation Proximal femur bionic nail(PFBN) Biomechanics Bone remodeling