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圆环上的逆shadowing映射(英文)
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作者 韩英豪 葛琦 南华 《延边大学学报(自然科学版)》 CAS 2005年第3期161-164,187,共5页
本文证明了圆环上shadowing性质和(Tc,Th-)逆shadowing性质的等价性.
关键词 shadowing性质 (Jc Jh^-)逆shadowing性质 shadowing性质
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Energy efficiency aware dynamic rate and power adaptation in carrier sensing based WLANs under Rayleigh fading and shadowing
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作者 Forkan Uddin 《Digital Communications and Networks》 SCIE CSCD 2024年第4期918-933,共16页
We consider the problem of energy efficiency aware dynamic adaptation of data transmission rate and transmission power of the users in carrier sensing based Wireless Local Area Networks(WLANs)in the presence of path l... We consider the problem of energy efficiency aware dynamic adaptation of data transmission rate and transmission power of the users in carrier sensing based Wireless Local Area Networks(WLANs)in the presence of path loss,Rayleigh fading and log-normal shadowing.For a data packet transmission,we formulate an optimization problem,solve the problem,and propose a rate and transmission power adaptation scheme with a restriction methodology of data packet transmission for achieving the optimal energy efficiency.In the restriction methodology of data packet transmission,a user does not transmit a data packet if the instantaneous channel gain of the user is lower than a threshold.To evaluate the performance of the proposed scheme,we develop analytical models for computing the throughput and energy efficiency of WLANs under the proposed scheme considering a saturation traffic condition.We then validate the analytical models via simulation.We find that the proposed scheme provides better throughput and energy efficiency with acceptable throughput fairness if the restriction methodology of data packet transmission is included.By means of the analytical models and simulations,we demonstrate that the proposed scheme provides significantly higher throughput,energy efficiency and fairness index than a traditional non-adaptive scheme and an existing most relevant adaptive scheme.Throughput and energy efficiency gains obtained by the proposed scheme with respect to the existing adapting scheme are about 75%and 103%,respectively,for a fairness index of 0.8.We also study the effect of various system parameters on throughput and energy efficiency and provide various engineering insights. 展开更多
关键词 Carrier sense multiple access Energy efficiency Fading and shadowing Rate and power adaptation THROUGHPUT Wireless local area networks
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Vision-Based Digital Shadowing to Reveal Hidden Structural Dynamics of a Real Supertall Building
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作者 Donglian Gu Qingrui Yue +2 位作者 Li Li Chujin Sun Xinzheng Lu 《Engineering》 CSCD 2024年第12期146-158,共13页
Vision-based digital shadowing is a highly efficient way to monitor the health of buildings in use.However,previous studies on digital shadowing have been limited to laboratory experiments.This paper proposes a novel ... Vision-based digital shadowing is a highly efficient way to monitor the health of buildings in use.However,previous studies on digital shadowing have been limited to laboratory experiments.This paper proposes a novel computer-vision-based digital shadow workflow and presents its successful application in a real engineering case.In this case,a 345.8-m supertall building experienced unexpected shaking under normal meteorological conditions.This study established a digital shadow of the building using three-dimensional displacement measurements based on super-resolution monocular vision,revealing the hidden structural dynamics and inherent mechanical reasons for the abnormal shaking.The proposed digital shadowing workflow is a feasible roadmap for developing vision-based digital shadows of realworld structures using low-cost cameras.The abnormal vibration event in the supertall building considered in this study is the first of its type worldwide.The results of this study offer practical strategies and invaluable insights into the prevention and mitigation of this type of global risk,thereby contributing to the lifespan extension of buildings in use worldwide.Furthermore,with the increasing number of general sensing devices,such as surveillance cameras in cities,the proposed method may unleash the immense potential of general sensing devices in achieving the leap from structural health monitoring to city health monitoring. 展开更多
关键词 Digital shadow Digital twin Super-resolution Monocular vision Displacement measurement Finite element simulation Deep learning Structural health monitoring
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基于Shadowing模型的无线入侵主机物理定位研究 被引量:4
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作者 付雄 彭冰 《微电子学与计算机》 CSCD 北大核心 2010年第12期4-9,共6页
为了在室内无线局域网环境中及时准确地定位非法入侵主机物理位置,以无线信号强度衰减过程的Shadowing传播模型为基础,研究了在一定的范围内如何合理地布置探测器,如何根据接收到的入侵主机的信号强度进行物理定位的问题.提出的定位方... 为了在室内无线局域网环境中及时准确地定位非法入侵主机物理位置,以无线信号强度衰减过程的Shadowing传播模型为基础,研究了在一定的范围内如何合理地布置探测器,如何根据接收到的入侵主机的信号强度进行物理定位的问题.提出的定位方法可以有效地对抗入侵主机随机更改信号发射功率对定位精度的影响.实际测试结果表明,该方法定位误差平均约为2.3 m,可以满足室内环境下定位非法入侵主机的需求. 展开更多
关键词 无线局域网 室内定位算法 信号强度 shadowing模型
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On the Relation of Shadowing and Expansivity in Nonautonomous Discrete Systems 被引量:9
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作者 Hossein Rasuli Reza Memarbashi 《Analysis in Theory and Applications》 CSCD 2017年第1期11-19,共9页
In this paper we study shadowing property for sequences of mappings on compact metric spaces, i.e., nonautonomous discrete dynamical systems. We investi- gate the relations of various expansivity properties with shado... In this paper we study shadowing property for sequences of mappings on compact metric spaces, i.e., nonautonomous discrete dynamical systems. We investi- gate the relations of various expansivity properties with shadowing and h-shadowing property. 展开更多
关键词 Key Words: shadowing h-shadowing locally expanding uniformly weak expanding locallyweak expanding.
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Review of Shadow Detection and De-shadowing Methods in Remote Sensing 被引量:11
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作者 AmirReza SHAHTAHMASSEBI YANG Ning +2 位作者 WANG Ke Nathan MOORE SHEN Zhangquan 《Chinese Geographical Science》 SCIE CSCD 2013年第4期403-420,共18页
Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,m... Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,mountain and urban materials.The shadow correction process consists of two steps:detection and de-shadowing.This paper reviews a range of techniques for both steps,focusing on urban regions(urban shadows),mountainous areas(topographic shadow),cloud shadows and composite shadows.Several issues including the problems and the advantages of those algorithms are discussed.In recent years,thresholding and recovery techniques have become important for shadow detection and de-shadowing,respectively.Research on shadow correction is still an important topic,particularly for urban regions(in high spatial resolution data) and mountainous forest(in high and medium spatial resolution data).Moreover,new algorithms are needed for shadow correction,especially given the advent of new satellite images. 展开更多
关键词 SHADOW detection de-shadowing URBAN FOREST
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Lipschitz Shadowing Property for 1-Dimensional Subsystems of Z^(k)-Actions 被引量:5
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作者 Lin WANG Jinlian ZHANG 《Journal of Mathematical Research with Applications》 CSCD 2021年第6期615-628,共14页
In this paper,the shadowing property for 1-dimensional subsystems of Z^(k)-actions is investigated.The concepts of pseudo orbit and shadowing property for 1-dimensional subsystems of Z^(k)-actions are introduced in tw... In this paper,the shadowing property for 1-dimensional subsystems of Z^(k)-actions is investigated.The concepts of pseudo orbit and shadowing property for 1-dimensional subsystems of Z^(k)-actions are introduced in two equivalent ways.For a smooth Z^(k)-action T on a closed Riemannian manifold,we propose a notion of Anosov direction via the induced nonautonomous dynamical system.Adapting Bowen’s geometric method to our case,we show that T has the Lipschitz shadowing property along any Anosov direction. 展开更多
关键词 Z^(k)-actions Lipschitz shadowing 1-dimensional subsystem
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Numerical study of hydraulic fracturing in the sectorial well-factory considering well interference and stress shadowing 被引量:2
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作者 Yu-Hao Liu Jin-Tao Zhang +2 位作者 Jie Bai Feng-Shou Zhang Ji-Zhou Tang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第6期3567-3581,共15页
In the Changqing Oilfield in northwest China, when traditional petroleum exploitation encounters forestry reserves or water source protection areas, sectorial well-factory design is proposed. The most distinct feature... In the Changqing Oilfield in northwest China, when traditional petroleum exploitation encounters forestry reserves or water source protection areas, sectorial well-factory design is proposed. The most distinct feature of a sectorial well-factory is the deviation of the well from the minimum horizontal principal stress, resulting in hydraulic fracture deflection after the initiation, along with possible well interference (i.e., fracture hit) and fracture coalescence in the oblique wells. Four indexes describing well deflection are then proposed according to fracture morphology. Several fracturing designs, including stage arrangement, fracturing sequences, and fracturing techniques are applied to study the feasibility of the sectorial well-factory design. The results show that the “gradual” or “sparse” stage arrangement, large injection rate, and simultaneous multifracture treatment can help to optimize the fracture morphology and stimulation design. However, the subsequent stress shadowing effect usually adversely affects the fracturing of adjacent wells. With a small initial horizontal stress difference, large injection rate and staggered stage arrangement can achieve ideal stimulation performance. Our results can provide a guidance for optimizing stimulation design in unconventional well-factory while taking into account environmental protection. 展开更多
关键词 Hydraulic fracturing Sectorial well-factory Fracture deflection Well interference Stress shadowing
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Inhomogeneous Shadowing Effect in High-Energy p-A Drell-Yan Process: 被引量:2
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作者 WANG Hong-Min SUN Xian-Jing ZHANG Ben-Ai 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第7期175-179,共5页
Having studied the initial state energy loss versus nuclear shadowing for the Drell-Yan dimuon pairproduction in the color string model,the inhomogeneous shadowing effect is considered in this paper.We find thatthe in... Having studied the initial state energy loss versus nuclear shadowing for the Drell-Yan dimuon pairproduction in the color string model,the inhomogeneous shadowing effect is considered in this paper.We find thatthe inhomogeneous shadowing effect does amend the rate of energy loss per unit path length,-dE/dz.Finally,thetheoretical results for the Drell-Yan differential cross-section ratios are compared with the E772 and E866 data.It isfound that the theoretical results are in good agreement with the experimental data. 展开更多
关键词 inhomogeneous shadowing effect color string model Drell Yan process
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SHADOWING,EXPANSIVENESS AND SPECIFICATION FOR C^1-CONSERVATIVE SYSTEMS 被引量:1
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作者 Mario BESSA Manseob LEE 文晓 《Acta Mathematica Scientia》 SCIE CSCD 2015年第3期583-600,共18页
We prove that a Cl-generic volume-preserving dynamical system (diffeomor- phism or flow) has the shadowing property or is expansive or has the weak specification property if and only if it is Anosov. Finally, as in ... We prove that a Cl-generic volume-preserving dynamical system (diffeomor- phism or flow) has the shadowing property or is expansive or has the weak specification property if and only if it is Anosov. Finally, as in [10, 27], we prove that the Cl-robustness, within the volume-preserving context, of the expansiveness property and the weak specifica- tion property, imply that the dynamical system (diffeomorphism or flow) is Anosov. 展开更多
关键词 shadowing EXPANSIVENESS SPECIFICATION GENERIC Anosov volume-preserving star systems
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关于“shadowing exercise”方法在日语语法教学中的延伸应用研究
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作者 韦大伟 《教师》 2014年第29期56-56,共1页
在教学过程中发现,很多学生无法摆脱母语迁移的负面影响。学习语法时,习惯将语法的语义高度概括并用汉语记忆,将例句的译文优先记忆,以辅助回忆日语原句。这导致很多学生的学习滞步不前。本文借鉴"shadowing exercise"方法,将其应用... 在教学过程中发现,很多学生无法摆脱母语迁移的负面影响。学习语法时,习惯将语法的语义高度概括并用汉语记忆,将例句的译文优先记忆,以辅助回忆日语原句。这导致很多学生的学习滞步不前。本文借鉴"shadowing exercise"方法,将其应用延伸至日语语法教学中,以期帮助学生摆脱母语迁移的负面影响。 展开更多
关键词 shadowing EXERCISE 母语迁移 延伸应用
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A GENERALIZED LIPSCHITZ SHADOWING PROPERTY FOR FLOWS
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作者 韩波 Manseob LEE 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期259-288,共30页
In this paper,we define a generalized Lipschitz shadowing property for flows and prove that a flowΦgenerated by a C1vector field X on a closed Riemannian manifold M has this generalized Lipschitz shadowing property i... In this paper,we define a generalized Lipschitz shadowing property for flows and prove that a flowΦgenerated by a C1vector field X on a closed Riemannian manifold M has this generalized Lipschitz shadowing property if and only if it is structurally stable. 展开更多
关键词 FLOW Perron property HYPERBOLICITY generalized Lipschitz shadowing property structural stability
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浅析“手机APP+Shadowing”学习法对韩语听说水平的提升作用
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作者 班斓 胥思名 《高考》 2018年第14期268-268,共1页
韩国,作为中国重要邻国之一,共处同一文化圈内,同中国一样,深受儒教文化影响。随着中韩建交以来,两国关系日益密切,教育文化等各个方面的学术交流日益频繁,再加上近年来深受'韩流'影响,学习韩国语的人也越来越多,本文以'学... 韩国,作为中国重要邻国之一,共处同一文化圈内,同中国一样,深受儒教文化影响。随着中韩建交以来,两国关系日益密切,教育文化等各个方面的学术交流日益频繁,再加上近年来深受'韩流'影响,学习韩国语的人也越来越多,本文以'学好韩国语的有效学习法——Shadowing学习法'为调查研究主题,希望能够简单有效的帮助学习者学好韩国语,从而促进中?韩两国关系得以进一步发展。 展开更多
关键词 韩国语学习法 shadowing学习法
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Precise Asymptotic Distribution of the Number of Isolated Nodes in Wireless Networks with Lognormal Shadowing
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作者 Lixin Wang Alberto Argumedo William Washington 《Applied Mathematics》 2014年第15期2249-2263,共15页
In this paper, we study the connectivity of multihop wireless networks under the log-normal shadowing model by investigating the precise distribution of the number of isolated nodes. Under such a realistic shadowing m... In this paper, we study the connectivity of multihop wireless networks under the log-normal shadowing model by investigating the precise distribution of the number of isolated nodes. Under such a realistic shadowing model, all previous known works on the distribution of the number of isolated nodes were obtained only based on simulation studies or by ignoring the important boundary effect to avoid the challenging technical analysis, and thus cannot be applied to any practical wireless networks. It is extremely challenging to take the complicated boundary effect into consideration under such a realistic model because the transmission area of each node is an irregular region other than a circular area. Assume that the wireless nodes are represented by a Poisson point process with densitynover a unit-area disk, and that the transmission power is properly chosen so that the expected node degree of the network equals lnn + ξ (n), where ξ (n) approaches to a constant ξ as n →?∞. Under such a shadowing model with the boundary effect taken into consideration, we proved that the total number of isolated nodes is asymptotically Poisson with mean e$ {-ξ}. The Brun’s sieve is utilized to derive the precise asymptotic distribution. Our results can be used as design guidelines for any practical multihop wireless network where both the shadowing and boundary effects must be taken into consideration. 展开更多
关键词 CONNECTIVITY ASYMPTOTIC Distribution Random Geometric Graph ISOLATED NODES log-Normal shadowing
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Inverse Shadowing and Weak Inverse Shadowing Property
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作者 B. Honary Alireza Zamani Bahabadi 《Applied Mathematics》 2012年第5期478-483,共6页
In this paper we show that an -stable diffeomorphism has the weak inverse shadowing property with respect to classes of continuous method and and some of the -stable diffeomorphisms have weak inverse shadowing propert... In this paper we show that an -stable diffeomorphism has the weak inverse shadowing property with respect to classes of continuous method and and some of the -stable diffeomorphisms have weak inverse shadowing property with respect to classes . In addition we study relation between minimality and weak inverse shadowing property with respect to class and relation between expansivity and inverse shadowing property with respect to class . 展开更多
关键词 INVERSE shadowing Property MINIMAL HOMEOMORPHISM δ-Method POSITIVE Expansive
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Gluon Shadowing,Absorption and Charmonium/Bottonium Suppression in h-A Processe
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作者 Chao Wei-qin Liu Bo(Institute of High Energy Physics,Academia Sinica,P.O.Box 918(4),Beijing 100039)(Center of Theoretical Physics,CCAST(World Lab.),Beijing) 《Chinese journal of nuclear physics》 1994年第3期189-194,共6页
The data of charmonium/bottonium suppression in p-A collisions at 800GeV/N are analyzed by considering the shadowing effect of the gluon structure func-tion at small x and the absorption in the target nuclei.An empiri... The data of charmonium/bottonium suppression in p-A collisions at 800GeV/N are analyzed by considering the shadowing effect of the gluon structure func-tion at small x and the absorption in the target nuclei.An empirical parametrization ofthe shadowing effect of the gluon structure function is deduced.The A-and x<sub>2</sub>-depen-dence of the suppression in p-A collisions is well described based on above physical con-siderations. 展开更多
关键词 QGP GLUON shadowing GLUON fusion ABSORPTION SUPPRESSION
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Economic analysis of rooftop photovoltaics system under different shadowing conditions for 20 cities in China 被引量:2
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作者 Zhiyi Ren Yixing Chen +2 位作者 Chengcheng Song Mengyue Liu Anni XuQilin Zhang 《Building Simulation》 SCIE EI CSCD 2024年第2期235-252,共18页
Installing photovoltaic(PV)systems is an essential step for low-carbon development.The economics of PV systems are strongly impacted by the electricity price and the shadowing effect from neighboring buildings.This st... Installing photovoltaic(PV)systems is an essential step for low-carbon development.The economics of PV systems are strongly impacted by the electricity price and the shadowing effect from neighboring buildings.This study evaluates the PV generation potential and economics of 20 cities in China under three shadowing conditions.First,the building geometry models under three shadowing conditions for the 20 cities were constructed using QGIS.Then,60 building models with PV systems and shadows from surrounding buildings were generated by City Buildings,Energy,and Sustainability(CityBES),an open platform,to simulate the PV power generation.Finally,the study presented one economic analysis model to evaluate the profitability by combining the market cost of rooftop PV systems and electricity prices in China.The economic model included four indicators:payback period(static and dynamic),net present value(NPV),and internal rate of return(IRR).The results show that the reduction of PV power generation ranges from 8.29%to 16.01%under medium shadowing,and experiences a maximum decrease of up to 39.71%under high shadowing.Further economic analysis shows that almost all the regions show reliable potential,obtaining an IRR higher than the reference value(5%).Nenjiang has the highest economic profit,with the highest NPV(86,181.15 RMB)and IRR(30.14%)under no shadowing among 20 cities.It also should be mentioned that the alignment between electricity price distribution and the solar power generation curve will directly impact the economic potential of PV systems. 展开更多
关键词 rooftop photovoltaic system ENERGYPLUS economic analysis shadowing buildings electric price
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Development and Validation of Instruments for Measuring Shadowing Exercises through Mobile-assisted Language Learning (MALL) in EFL Learning
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作者 Xiuzhen Jia Ooi Boon Keat 《Advances in Humanities Research》 2024年第4期29-37,共9页
This study aims to create a simple and effective way to measure how shadowing exercises using MALL help students learn English as a foreign language.Shadowing,the act of vocalizing speech simultaneously as it is heard... This study aims to create a simple and effective way to measure how shadowing exercises using MALL help students learn English as a foreign language.Shadowing,the act of vocalizing speech simultaneously as it is heard,is recognized for enhancing various language skills.The research aimed to develop and validate such an instrument grounded in standardized surveys.Methods employed included the Kaiser-Meyer-Olkin(KMO)Measure of Sampling Adequacy(.875)and Bartlett’s Test of Sphericity(χ²=659.572,df=55,p<.000)to assess data suitability for factor analysis.The survey instrument comprised 11 items assessing various aspects of shadowing exercises through MALL software.Factor analysis revealed a single dominant component explaining 75.929%of the total variance,indicating the construct's unidimensionality.Items related to challenges,benefits,and intended integration of MALL-based shadowing exercises into daily learning routines exhibited higher loadings,aligning strongly with the latent construct.Results underscore the potential of MALL-facilitated shadowing exercises as an effective tool to enhance EFL learners’overall language proficiency and motivate their learning journey.This study contributes to the growing body of research on the integration of MALL in shadowing exercises,offering a reliable and streamlined means to measure the impact of such interventions. 展开更多
关键词 shadowing exercises using Mobile-assisted Language Learning(MALL) development and validation of instruments pronunciation intonation oral English fluency EFL
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光纤光栅传感网络恶意攻击篡改信标节点安全定位方法
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作者 王文霞 李智玲 杨文彬 《激光杂志》 北大核心 2025年第4期198-202,共5页
为了防止恶意节点攻击篡改信标节点信息,保护网络正常运行的同时提高信标节点定位精度,提出光纤光栅传感网络恶意攻击篡改信标节点安全定位方法。首先,计算节点信任值,将计算结果作为恶意节点判断依据,识别恶意节点并剔除;其次,采用Boun... 为了防止恶意节点攻击篡改信标节点信息,保护网络正常运行的同时提高信标节点定位精度,提出光纤光栅传感网络恶意攻击篡改信标节点安全定位方法。首先,计算节点信任值,将计算结果作为恶意节点判断依据,识别恶意节点并剔除;其次,采用Bounding-box算法搜索未知信标节点其所在区域,完成节点的初步定位;最后,建立Shadowing模型结合质心算法,计算信标节点的具体位置坐标。实现光纤光栅传感网络恶意攻击篡改信标节点安全定位方法。仿真实验结果表明,所提方法对恶意节点检测率高,信标节点定位精度高,覆盖性强。 展开更多
关键词 传感网络 恶意节点检测 信标节点定位 shadowing模型
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Shadowing and Inverse Shadowing for C^1 Endomorphisms 被引量:2
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作者 Yu Jun ZHU Jin Lian ZHANG Lian Fa HE 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2006年第5期1321-1328,共8页
In this paper, we consider the shadowing and the inverse shadowing properties for C^1 endomorphisms. We show that near a hyperbolic set a C^1 endomorphism has the shadowing property, and a hyperbolic endomorphism has ... In this paper, we consider the shadowing and the inverse shadowing properties for C^1 endomorphisms. We show that near a hyperbolic set a C^1 endomorphism has the shadowing property, and a hyperbolic endomorphism has the inverse shadowing property with respect to a class of continuous methods. Moreover, each of these shadowing properties is also "uniform" with respect to C^1 perturbation. 展开更多
关键词 shadowing property inverse shadowing property ENDOMORPHISM Hyperbolic set
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