检索结果-南通市图书馆

Dynamic defenses in cyber security:Techniques,methods and challenges Author links open overlay panel

Digital Communications and Networks 2022年第4期8卷 422-435页

作者： Yu zheng zheng Li Xiaolong Xu Qingzhan Zhao School of Computer and Software Nanjing University of Information Science and TechnologyNanjing210044JiangsuChina Key Laboratory for Novel Software Technology Nanjing UniversityNanjing210023JiangsuChina College of Information Science and Technology Shihezi University Geospatial Information Engineering Research CenterChina

Driven by the rapid development of the Internet of Things,cloud computing and other emerging technologies,the connotation of cyberspace is constantly expanding and becoming the fifth dimension of human ***,security problems in cyberspace are becoming serious,and traditional defense measures(e.g.,firewall,intrusion detection systems,and security audits)often fall into a passive situation of being prone to attacks and difficult to take effect when responding to new types of network attacks with a higher and higher degree of coordination and *** constructing and implementing the diverse strategy of dynamic transformation,the configuration characteristics of systems are constantly changing,and the probability of vulnerability exposure is ***,the difficulty and cost of attack are increasing,which provides new ideas for reversing the asymmetric situation of defense and attack in ***,few related works systematically introduce dynamic defense mechanisms for cyber *** related concepts and development strategies of dynamic defense are rarely analyzed and *** bridge this gap,we conduct a comprehensive and concrete survey of recent research efforts on dynamic defense in cyber ***,we firstly introduce basic concepts and define dynamic defense in cyber ***,we review the architectures,enabling techniques and methods for moving target defense and mimic *** is followed by taxonomically summarizing the implementation and evaluation of dynamic ***,we discuss some open challenges and opportunities for dynamic defense in cyber security.

关键词： Cyber security Dynamic defense Moving target defense Mimic defense

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Wind power and sand/dust storms

引用

Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 175-176页

作者： XiaoJing zheng Center for Particle-Laden Turbulence Lanzhou UniversityLanzhou 730000China

Sand/dust storms,a globally prevalent catastrophic weather phenomenon,can cause significant erosion to the climate and ecological *** high concentration of sand particles they carry not only impacts atmospheric qualit... 详细信息

关键词： Wind power and sand/dust storms

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Time-optimal guidance for intercepting moving targets with impact-angle constraints

引用

Chinese Journal of Aeronautics 2022年第7期35卷 157-167页

作者： Yuan zheng zheng CHEN Xueming SHAO Wenjie ZHAO School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China

The minimum-time path for intercepting a moving target with a prescribed impact angle is studied in the *** candidate paths from Pontryagin’s maximum principle are synthesized,so that each candidate is related to a zero of a real-valued *** is found that the real-valued functions or their first-order derivatives can be converted to polynomials of at most fourth *** a result,each candidate path can be computed within a constant time by embedding a standard polynomial solver into the typical bisection *** control strategy along the shortest candidate eventually gives rise to the time-optimal guidance ***,the developments of the paper are illustrated and verified by three numerical examples.

关键词： Dubins vehicle Guidance law Minimum-time path Optimal guidance Path planning

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Urban computing： enabling urban intelligence with big data

引用

Frontiers of Computer Science 2017年第1期11卷 1-3页

作者： Yu zheng Microsoft Research Beijing 100080 China School of Computer Science and Technology Xidian University Xi'an 710071 China Shenzhen Institutes of Adv.anced Technology Chinese Academy of Sciences Shenzhen 518055 China

Urban computing is a process of acquisition, integration and analysis of big and heterogeneous data generated by a diver- sity of sources in urban spaces, such as sensors, devices, ve- hicles, buildings and humans, to tackle the major issues that cities face, e.g., air pollution, energy consumption and traffic congestion. Urban computing connects unobtrusive and ubiq- uitous sensing technologies, advanced data management and analytics models, and novel visualization methods.

关键词： analysis big heterogeneous

来源：

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

WRIST FORCE SENSOR'S DYNAMIC PERFORMANCE CALIBRATION BASED ON NEGATIVE STEP RESPONSE

引用

Chinese Journal of Mechanical Engineering 2008年第5期21卷 92-96页

作者： zheng Hongmei School of Mechanical and Automobile Engineering Hefei University of Technology Hefei 230009. China

Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. This experimental method needn＇t special experiment equipments. Experiment＇s dynamic repeatability is good. So wrist force sensor＇s dynamic performance is suitable to be calibrated by negative step response method. A new correlation wavelet transfer method is studied. By wavelet transfer method, the signal is decomposed into two dimensional spaces of time-frequency. So the problem of negative step exciting energy concentrating in the low frequency band is solved. Correlation wavelet transfer doesn＇t require that wavelet primary function be orthogonal and needn＇t wavelet reconstruction. So analyzing efficiency is high. An experimental bench is designed and manufactured to load the wrist force sensor orthogonal excitation force/moment. A piezoelectric force sensor is used to setup soft trigger and calculate the value of negative step excitation. A wrist force sensor is calibrated. The pulse response function is calculated after negative step excitation and step response have been transformed to positive step excitation and step response. The pulse response function is transferred to frequency response function. The wrist force sensor＇s dynamic characteristics are identified by the frequency response function.

关键词： Wrist force sensor Dynamic performance calibration Step response experiment Correlation wavelet transfer Impulse response function

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Southwest China community velocity model V2.0:The key to decipher active tectonics and seismic hazards in Sichuan-Yunnan region

引用

Science China Earth Sciences 2023年第10期66卷 2395-2398页

作者： Yong zheng State Key Laboratory of Geological Processes and Mineral Resources School of Geophysics and GeomaticsChina University of GeosciencesWuhan430074China Hubei Subsurface Multi-Scale Imaging Key Laboratory Wuhan430074China

*** of the Southwest China community velocity model(SWChina CVM),As a result of the collision between the Indian and Eurasian Plates,crustal materials in the Tibetan Plateau extrude southeastward,leading to a series o... 详细信息

关键词： seismic crustal Eurasian

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quantum Decoherence of Macroscopic Object Induced by Inner Environments： an Exactly Solvable Model

引用

Communications in Theoretical Physics 2007年第2期47卷 229-234页

作者： zheng Li zheng Tai-Yu College of Info Science and Engineering Dalian Institute of Light Industry Dalian 116034 China Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China The Institute of Theoretical Physics Northeast Normal University Changchun 130022 China

We revisit the quantum decoherence problem of the center of mass motion of a macroscopic object, which is modelled as a one-dimensional atom chain. Induced by the coupling of the center of mass （C.M） motion with the inner degrees of freedom, this inner-environment-induced decoherence is reflected by the localization of the C.M wave packet. We show that, the C.M motion is coupled to the inner states only when the chain has interaction with the external potential. This result provides a realistic mechanism for the analysis of the inner-environment-induced localization of a macroscopic object.

关键词： quantum decoherence macroscopic object inner environments

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fatigue-resistant sliding ferroelectricity

引用

Science China Materials 2024年第10期67卷 3417-3418页

作者： zheng Liu School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore

The direction of spontaneous polarization in ferroelectricity can be reoriented by an external electric *** special feature of ferroelectricity is important candidates for fabricating advanced nonvolatile random-access memory[1].However,repeatedly switching polarization induces the ferroelectric device performance degenerates due to a reduction of polarization.

关键词： polarization ferroelectric field.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ELASTICITY MODULUS OF RANDOM COMPOSITE AND ELASTIC PERCOLATION FAILURE OF SOLIDS

引用

Chinese Physics Letters 1990年第10期7卷 457-460页

作者： zheng Maosheng zheng xiulin Department of Physics Xian University of Electronic Science and TechnologyXian 710071 Department of Materials Science and Engineering Northwestern Polytechnical UniversityXian 710072

The elasticity modulus of random composite is obtained in 2 and 3 dimensional spaces,based on the solutions of over-matching problems in elastic mechanics.A system with 2 components is also considered,and the calculated results are in good agreement with available ***,taking the voids and defects in materials as the second phase with zero modulus,one can easily obtain the expressions for predicting modulus and threshold of the elastic percolation failure of materials containing voids,and the results agree excellently with those in available literatures.

关键词： modulus elasticity matching

来源：

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

The transport of water in subduction zones

引用

Science China Earth Sciences 2016年第4期59卷 651-682页

作者： zheng YongFei CHEN RenXu XU zheng ZHANG ShaoBing School of Earth and Space Sciences University of Science and Technology of China

The transport of water from subducting crust into the mantle is mainly dictated by the stability of hydrous minerals in subduction zones. The thermal structure of subduction zones is a key to dehydration of the subducting crust at different depths. Oceanic subduction zones show a large variation in the geotherm, but seismicity and arc volcanism are only prominent in cold subduction zones where geothermal gradients are low. In contrast, continental subduction zones have low geothermal gradients, resulting in metamorphism in cold subduction zones and the absence of arc volcanism during subduction. In very cold subduction zone where the geothermal gradient is very low(?5?C/km), lawsonite may carry water into great depths of ?300 km. In the hot subduction zone where the geothermal gradient is high(>25?C/km), the subducting crust dehydrates significantly at shallow depths and may partially melt at depths of <80 km to form felsic melts, into which water is highly dissolved. In this case, only a minor amount of water can be transported into great depths. A number of intermediate modes are present between these two end-member dehydration modes, making subduction-zone dehydration various. Low-T/low-P hydrous minerals are not stable in warm subduction zones with increasing subduction depths and thus break down at forearc depths of ?60–80 km to release large amounts of water. In contrast, the low-T/low-P hydrous minerals are replaced by low-T/high-P hydrous minerals in cold subduction zones with increasing subduction depths, allowing the water to be transported to subarc depths of 80–160 km. In either case, dehydration reactions not only trigger seismicity in the subducting crust but also cause hydration of the mantle wedge. Nevertheless, there are still minor amounts of water to be transported by ultrahigh-pressure hydrous minerals and nominally anhydrous minerals into the deeper mantle. The mantle wedge overlying the subducting slab does not partially melt upon water influx

关键词： Subduction zones Oceanic crust Mantle wedge Thermal structure Hydrous minerals Water transport Arc magmatism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：