摘要：利用动态参数的离散斜帐篷映射,结合简单的一维混沌映射像素值替代方法,提出了一种改进的基于离散斜帐篷映射的混沌加密方法.仿真结果表明,该方法不仅继承了原有系统的优良密码学特性,而且与传统斜帐篷混沌序列加密算法相比,在图像不失真的情况下大大增强图像加密的安全性.%A new chaotic cryptosystem based on skew tent map was proposed by making use of a mixed chaotic sequences, which are produced by combining the dynamic encryption parameter and a simple sin-gle-dimensional chaotic map. The simulation result shows the proposed cryptosystem inherited the advanta-ges of the original one and it shows that the proposed algorithm greatly enhances the security of image en-cryption without image distortion comparing with the traditional skew tent map chaotic encryption algo-rithm.
摘要：Asymptotical stability is an important property of the associative memory neural networks. In this comment, we demonstrate that the asymptotical stability analyses of the MV-ECAM and MV-eBAM in the asynchronous update mode by Wang et al are not rigorous, and then we modify the errors and further prove that the two models are all asymptotically stable in both synchronous and asynchronous update modes.
摘要：提出了基于区域的立体匹配算法,实现从彩色立体图像对中提取深度信息.其中利用平滑函数求取全局错误能量最小化获得的视差图更为可靠,但是计算时间也较长；而采用线性生长算法获得的视差图则计算时间短,但可靠性差.结果是利用滤波去掉了不可靠的视差估计,可以提高视差图的可靠度,还对算法生成的结果进行了比较.%In the paper,region based stereo matching algorithms are developed for extracting depth infor-mation from two color stereo image pair. It shows that global error energy minimization by smoothing func-tions method is more reliable but more time consuming, and that line growing method is more convenient for the sequential computing architectures because of promising higher speed. Filtering unreliable disparity estimation can increase reliability of disparity map. Finally, a comparison of the algorithms is presented.
摘要：A game-theory based static spectrum sharing model is proposed for cognitive radio,which supports multiple secondary users competitively sharing one primary user systems idle spectrum.The primary user systems benefit function based on Self-discipline mechanism is established.Reasonable price is determined considering both primary user's spectrum demands and no wasting of the remaining free spectrum.Dynamic spectrum sharing algorithm is introduced,in which the secondary users can continuously adjust their strategies to reach Nash equilibrium and maximize their benefits.%提出了基于博弈论的认知无线电静态频谱共享模型,研究多个次级用户竞争一个主用户系统的空闲频谱.建立了基于自我约束机制的主用户系统的效益函数,主用户系统兼顾自身频谱需求与不浪费剩余的空闲频谱两方面来确定合适的价格,并引入了动态频谱共享算法,次级用户能不断调整自己的策略最终趋于纳什均衡,最大化自身效益.
摘要：由于Ad Hoc网络的特殊性,安全路由协议成为其研究的一个热点.当前已提出的一些安全路由协议都还不太完善.主要针对安全路由协议SEAD的不足,提出了S-SEAD协议,尤其对其哈希链再生时的安全问题提出了一种新的哈希链安全再生方法,从而保证哈希链的连续性,并且不需要任何可信任的中心机构,符合Ad Hoc网络无中心的特点.最后针对改进前后的协议,在安全性和执行效能方面用NS2平台进行了仿真,结果表明S-SEAD协议虽然微小增加了数据包的收发时延和总开销,却保证了更好的安全性.%Owing to the peculiarity of Ad Hoc networks,the secure routing protocol is becoming a hot topic.Considering the existing secure routing protocols are imperfect,S-SEAD is proposed to attack the insufficiencies of SEAD protocol.,It provides a new hash chain re-initialization mechanism,which can make the hash chain continuous without trusted authority to meet the acentric network requirement of Ad Hoc networks.In term of security and execution efficiency,simulations on NS2 platform have shown that S-SEAD protocol has improved security at the cost of a little bit increase of packet send/receive delay and overall overhead.
摘要：P2P traffic identification model is constructed based on the ensemble learning algorithm ,which integrate DTNB,ONER and BP neural network algorithm.Using network flow characteristics and the integrated classification algorithm for rule generation in machine learning,network traffic flow is divided into two types,P2P and non-P2P traffic.The model consists of three steps,I.E.Gaining network flow characteristics,P2P traffic feature selection and the establishment of flow classification model.The rationality of the model and the effectiveness of the proposed method are evaluated using method of combining T-fold cross-validation and test sets.The experiment results have shown that the average precision of traffic classification reaches 97.27% and the model has relatively high P2P flow identification accuracy.%将DTNB、OneR和BP神经网络算法集成用于P2P流量识别,构建了基于该集成学习算法的P2P流量识别模型.利用网络流量特征和机器学习中生成规则的集成分类算法将网络流量分为P2P流量和非P2P流量.所建立的P2P流量识别模型分为网络流量特征的获取、P2P流量特征选取以及建立流量分类模型三个步骤.采用十折交叉验证与测试集相结合的方法CTFCVWTS( combining T-fold cross validation with testing set)评估模型的合理性和提出方法的有效性.实验得出流量分类准确率平均为97.27％.结果表明,该模型具有较高的P2P流量识别准确率.
摘要：发展了一种简单的用二氧化锰修饰碳纳米管的方法.二氯化锰水溶液在微波辐射下直接转化为二氧化锰,所得的二氧化锰纳米颗粒沉积在碳纳米管上.透射电镜结果表明二氧化锰纳米颗粒尺寸分布均匀.场发射扫描电镜结果表明二氧化锰纳米颗粒和碳纳米管交错形成三维的网状结构.能谱证明了二氧化锰纳米颗粒沉积在碳纳米管上.循环伏安结果显示沉积二氧化锰纳米颗粒/碳纳米管复合电极的性能优于纯的碳纳米管电极.%A simple approach to decorate multiwalled carbon nanotubes with MnO2 has been developed.In this method,MnC12 solution was directly transformed into MnO2 by microwave irradiation,and the produced MnO2 deposited on MWCNTs.Transmission electron microscopy (TEM) result showed that MnO2 nanoparticles had the uniform size distribution.Field emission scan electron microscopy (FE-SEM) result showed that MnO2 nanoparticles cross-linked MWCNTs in a quasi three-dimensional network.Energy dispersive X-rays (EDX) spectra elucidated the presence of manganese oxide in the as-prepared composites.Cyclic voltammetry result demonstrated that a specific capacitance of deposited manganese oxide electrode was significantly greater than that of the pristine MWCNTs electrode in the same medium.
摘要：In this paper,we analyze the current situation,and presented the PRIRR-PRIRR scheduling algorithm based on the two conceptions of unstable VOQ and unstable cross-point buffer to serve the cells in unstable VOQs first.The simulation results show that PRIRR-PRIRR can offer very good performance on average delay and stability for no-uniform traffic with Bernoulli arrivals,which solves the shortcoming of RR-RR algorithm completely.%研究了基于交叉点缓存的各种调度算法和基于CICQ的交换结构,运用非稳定VOQ和非稳定交叉点缓存两个概念,提出了PRIRR-PRIRR算法,保证了非稳定VOQ被优先轮询.仿真分析表明,该算法在非均匀分布业务源的情况下具有良好的平均时延性能和稳定性能,彻底解决了RR-RR算法在非均匀业务源下的不稳定缺陷.
摘要：提出了一种新的基于小波变换和FARIMA模型的流量预测方法,首先对原始流量进行小波分解,再进行mallat算法单支重构,接着用FARIMA模型分别对重构后的单支进行预测,最后整合流量.我们用真实网络流量进行了仿真实验,验证了提出算法的预测准确性,较之首先用FARIMA模型对小波系数进行预测再进行小波重构的方法减小了预测误差.%A new network traffic prediction scheme is proposed based on wavelet transformation and FARI-MA Model.Following the decomposition of original traffic with wavelet,each branch is reconstructed with mallat algorithm.Then prediction of reconstructed branch is conducted using FARIMA Model and finally the traffic is integrated.Simulations with real network traffic have verified the precision of proposed prediction algorithm.Compared with the method that first predicts the wavelet coefficients with FARIMA model and then reconstructs the traffic,the proposed method reduces the prediction error.
摘要：Definition and structure are given of nth-order hidden Markov models.Forward-backward algorithm and Baum-Welch algorithm of the models are studied based on the traditional second-order hidden Markov model.Parameter estimation equations for the models are derived for the cases of both single and multiple observation sequence training.%给出了n阶隐马尔可夫模型( HMMn)的定义及结构.在传统的隐马尔可夫模型及二阶隐马尔可夫模型( HMM2)的基础上研究了HMMn的前向、后向算法,Baum-Welch算法,并导出了HMMn在单观测序列和多观测序列培训两种情况下的参数估计公式.
摘要：In this paper we give quantitative version for the set made of admission kneading sequences with probability metric.It is proved for the set that the Hausdorff dimension is 1 and the 1-dimension Hausdorff measure is zero inΣ2.%对单峰映射的允许揉搓序列组成的一类集合给出定量的刻画,证明了该集合在概率度量下的符号空间中的Hausdor ff维数为1,1维Hausdor ff测度为零.
摘要：Synthetic aperture radar is a modern microwave imaging radar with high resolution in all weather all day,this paper analyses models of mono-static and multi-static,radar images are obtained using FDTD simulation and back projection,and in the end this research verify high resolution in through wall imaging using this kind of radar.Various effects of presence of the wall,such as refraction,changing in speed,and attenuation,can defocus target images,displace targets from their true positions and possibly produce false targets.So it is very important to consider the effects of wall in imaging algorithm.%合成孔径雷达(Synthetic Aperture Radar,SAR)是一种全天候、全天时的现代高分辨率微波成像雷达.分析了收发共置天线模型和多元静态雷达模型,FDTD建模模拟了室内目标探测场景,通过后向投影算法(back projection,BP)得到雷达图像,很好的验证了该雷达用于穿墙中的高分辨率成像.电磁波在穿墙传播时发生折射,速度的改变、信号的衰减,这些影响将导致像的散焦、偏移,甚至可能产生虚像,所以成像算法中必须考虑墙体作用.
摘要：In the underlay cognitive radio scenario,considering Amplified and Forward cooperative relay multiuser OFDM A cognitive networks,the resource allocation problem is discussed for the purpose of maximizing the overall data rate for all secondary users under the constraints of interference temperature.An optimal power allocation algorithm and suboptimal equal power allocation algorithm are proposed.They are combined with the traditional equal subchannels'pre-allocation scheme and the author proposed optimal subchannels'allocation scheme respectively.Simulation shows that the proposed algorithms provide better performance gain.%基于下垫式的认知无线电场景,针对基于放大转发协作中继的多用户正交频分多址接入认知网络,讨论了在干扰温度约束条件下,使认知用户总传输速率得到最大化的资源分配问题,提出了一种最优的功率分配算法和次优的等功率分配算法.将这两种功率分配算法分别与传统的相等子信道预分配方案和文中采用的最优子信道预分配方案相结合,仿真结果表明,所提的方案可得到更加优越的性能.
摘要：考虑认知用户传输功率受限,两认知用户与授权用户之间相对位置在三维空间任意分布,受到地理信息、射频环境和环境背景等多维因素影响,研究了一种无线环境下的判别协同感知性能优劣的模型,并通过相应的数值仿真验证所提的优化方案.研究结果表明:协同感知性能受到路径损耗指数、衰减因子、用户间相对位置变化和用户传输功率等多维参数的相互制约,但是在满足一定条件时存在优化的可能,甚至有很大优化空间.%Taking into account the constrained cognitive user transmission power,the random distribution of relative positions between two cognitive users and the licensed user in the three-dimensional space,the context effects of geographical information,the RF environment and the environmental background,a model is proposed capable of evaluating the performance of collaborative spectrum sensing under the wireless environment.The feasibility of the model is well explained and supported by extensive simulations.The study results indicate that the collaborative spectrum sensing performance is affected by multiple factors including path loss exponent,fading factor,the relative position changes between users and user transmission power.Optimization can be achieved under certain conditions,maybe with great improvement in some cases.
摘要：Operating principle of multi-layered balanced antipodal ultra-wideband (UWB) slot antennas having low cross-polarization characteristics are analyzed first by employing equivalent principle and theory of electrical-magnetic composite dipoles.The effects of the tuning stubs' shapes on the antennas' impedance matching,cross-polarization and gain are then investigated by using full-wave electromagnetic simulator.It is shown that the tuning stubs' shapes affect the antennas' return loss more significantly than the antennas' radiation characteristics within the frequency range.These results should be useful for the optimization design of UWB balanced antipodal slot antennas having low cross-polarization characteristics.%利用等效原理和电-磁组合振子理论,分析了具有低交叉极化特性的多层超宽带平衡对跖缝隙天线的工作原理,并通过数值仿真,详细研究了调谐枝节形状对带内匹配、交叉极化特性和天线增益的影响.结果表明,调谐枝节形状对超宽带天线的回波损耗特性有较明显的影响,而对天线的辐射影响较小.此研究工作将为低交叉极化特性超宽带平衡对跖缝隙天线的优化设计提供理论依据.
摘要：提出了一种在车辆ad-hoc网络中进行自适应资源分配的新方法.基于交通流量模型,对于不同的交通状态下的分配策略和性能进行了分析.采用Markov链建立了道路的统计模型,并得到了平均分配容量和拒绝概率.这种方法的主要特点是利用对于相邻小区的联合感知结果来进行预测,从而得到了比均匀分配更好的性能.仿真结果证明了该方法的有效性.%In this paper,a new approach of resource allocation for Vehicular ad-hoc network (VANET) is proposed.The traffic model based adaptive allocation is analyzed under different traffic flow conditions and with Markov modeling.The overall average capacity and the failure probability are derived.This method,characterized by its joint sensing and prediction of road status in neighboring cells,is proved with simulation to be able to outperform the normal uniform allocation,especially in free flow case.
摘要：In order to alleviate people from tedious manual work and provide remote monitoring to un-reachable region,intelligent car monitoring and command response are implemented using three tiers portal framework development technology.The wireless receiver installed in the car is connected to the monitoring computer through wireless transmitter.The computer forwards the received data to the server based on C/S mode with JNI(Java Native Interface).The response control web services deployed on the server handle the received data and return the result displayed on the client based on Java developed B/S mode.The practice shows that the integrated system with two interactive modes has the metrics of controlling the intelligent car with low cost and easy operation.%为了使人们从繁琐的劳作中解放出来以及实现对不可达区域的实时远程监控,利用三层门户框架开发技术实现对智能监测小车的监控和命令响应.小车端装有无线接受装置,通过无线发射器与监测电脑相连,监测电脑将接收到的数据传到服务器上,此过程是Java调用DLL本地化的C/S交互模式.在服务器上部署响应控制的Web服务接收,处理小车采集到的数据并回显给客户机,此过程是Java开发的B/S交互模式.实践表明,系统的两种交互模式的集成使用户对机器小车的控制具有成本低、操作性强等优点.
摘要：诱导的I(L)-拓扑向量空间具有与诱导它的L-拓扑向量空间很多类似的性质,而广义局部凸L-拓扑向量空间是一类重要的L-拓扑向量空间.讨论了诱导的I(L)-拓扑向量空间的广义局部凸性,并证明了一个诱导的I(L)-拓扑向量空间是广义局部凸的当且仅当诱导它的L-拓扑向量空间是广义局部凸的.%An induced I(L)-topological vector space has many properties similar to that of the corresponding L-topological vector space,while generalized locally convex L-topological vector space is an important kind of L-topological vector space.In this paper,local convexity of induced I (L) -topological vector spaces is discussed and it is proved that an L-topological vector space is generalized locally convex if and only if its induced I(L)-topological vector space is.
摘要：Statistical analysis is made of propensities of amino acids and nucleotides usage at protein-nucleic acid interfaces by hydrogen bonds or van der Waals contacts.The results have shown that: (1) For the number of van der Waals contacts,it is roughly the same as that of hydrogen bonds in the protein-DNA complex structures,but is far more than the latter in the protein-RNA complex structures.(2) In protein-nucleic acid complex structures,there are significant differences between the interaction propensities of amino acids recognizing nucleotides by hydrogen bonds and by van der Waals contacts.(3) The size and orientation of the polarity of amino acids play important roles in determining whether they bind DNA /RNA molecules by hydrogen bonds or van der Waals contacts.%对蛋白质-核酸复合物结构中氢键/范德华力作用位点氨基酸与核苷酸的偏好性(即相对使用频率)进行了统计分析.发现:(1)在蛋白质-DNA复合物结构中,范德华力作用对与氢键数量相当；而在蛋白质-RNA复合物结构中,范德华力作用对数量要远多于氢键；(2)复合物结构中氢键和范德华力作用位点上对氨基酸的偏好性差异显著；(3)氨基酸的极性大小及方向在决定它是否与DNA/RNA分子形成氢键/范德华力相互作用时起到重要的作用.
摘要：To investigate the problem of traffic grooming in WDM optical networks for both uniform and non-uniform traffic patterns,an ILP (Interger Linear Programming) algorithm and a heuristic algorithm are presented.The optimization objective of traffic grooming is to minimize the number of optical transceivers and wavelengths for a given traffic matrix.Taking WDM rings as examples,numerical results derived verify the effectiveness of the heuristic algorithm.It also demonstrates that the bigger the scale of ring networks,the more lightpaths reduced by traffic grooming,and the more obvious the effect of traffic grooming.%采用整数线性规划算法和启发式算法对均匀和非均匀业务模式下WDM (Wavelength Division Multiplexing)网络的业务疏导问题进行研究,优化目标为最小化给定业务矩阵情况下所需光收发机和波长数.以环网为例进行了数值仿真,数值结果验证了启发式算法的有效性,并表明随着环网规模的增大,通过疏导减少的光通道数越来越大,疏导的效果也越来越明显.
摘要：为了实现快速、高质量的图像传输,用尽可能少的小波系数高质量地表征图像,提出了一种基于二维小波变换的图像压缩算法.首先将图像进行二维小波分解,得到各子带的一系列小波系数；其次保留图像低频子带的所有小波系数；然后根据归一化能量序列熵准则提取其他各层子带重要系数,即在某一门限下剩余系数熵值与剩余系数最大熵值比值较大(0.9左右)时,可以忽略这些小波系数,从而实现数据压缩；最后将各子带重要系数进行量化、编码.接收端根据接收到的数字信号重构图像信号.实验中对图像信号进行了压缩实验,验证了所提算法的正确性和有效性.实验结果表明本算法简单可行、搜索量小,为图像压缩找到了一种新的有效方法,具有一定的实际应用价值.%In order to realize high-speed image transmission with high-quality and use minimum wavelet coefficients to display the image,an image compression algorithm is proposed based on two-dimensional wavelet transformation.Firstly,the image is decomposed with two-dimensional wavelet to obtain a series of wavelet coefficients for each subband.Secondly,all wavelet coefficients of low-frequency subband are retained.Thirdly,important coefficients are extracted according to entropy criterion of normalized energy sequence.When the ratio of remainder coefficients entropy value and its maximum entropy value is relatively big (0.9 or so),these remainder coefficients can be neglected and data compression is realized.Finally,important coefficients of each subband are quantized and encoded.In the receiving terminal the image is reconstructed according to received digital signal.Experiments with compressed image signals verify the correctness and effectiveness of this algorithm.The results have shown that this algorithm is simple and feasible,and its search workload is small.It provides a new effective method for image compression and has practical application value.
摘要：基础设施辅助路由技术能有效提高网络容量,减轻普通节点的能量消耗,因而成为容迟网络路由研究领域中的研究热点.概述了容迟网络路由技术面临的挑战、理论基础和评价指标,对基础设施辅助路由协议进行了分类,详细介绍了目前主要基础设施辅助路由协议的基本原理和特点,并进行深入分析和比较,最后给出了未来研究万向.%DTN (Disruption/Delay Tolerant Networks) can interconnect highly heterogeneous networks a-mong extreme environments even between nodes without end-to-end path.As the key components of DTN,routing technology is a challenge and promising research field.Infrastructure assistant routing is an efficient technology to improve the network capacity and reduce the energy consumption of ordinary nodes.This paper introduced the challenges,theoretical basis and evaluation index of routing in DTN.Then the basic principle and features of infrastructure assistant routing protocols were described.Finally,we analyzed and compared these routing protocols,identified future research issues and intended to motivate new research and development in this area.
摘要：The polarization model is the significant polarization characteristics in the radio prapogation.In this paper,the prapogation characteristics of indoor wireless radiowave has been studied based on the method of Shooting-and-Bounding Ray/Image (SBR/Image).Furthermore,the Field strength including the polarization characteristics of two-times reflection has been put forward.Finally,The path loss and field strength has been predicted in typical indoor office environment.A good agreement is achieved between the simulated results and the published results.%极化方式是电波传播中的重要特性,基于入射及反弹射线/镜像方法(SBR/Image)研究了室内无线电波传播特性,推导出在两次反射条件下包含极化特性的场强计算公式.最后,在典型的室内办公环境进行路径损耗和场强预测.通过仿真计算,和已知文献结果对比,一致性良好.
摘要：Most of the current OFDMA resource allocation algorithms targets on the spectrum utilization improvement in single system without considering the resource sharing for multi-system in the same area.To deal with this problem,a semi-static resource allocation strategy is proposed applicable to dual wireless system.First of all,a sharing spectrum region is chosen with the priority between systems being set.Then a Poisson evaluation mechanism is introduced to control the probability of accessing the spectrum sharing region for different systems so as to reduce the inter-system interference.The simulation results have shown that the proposed resource allocation strategy can effectively realize the spectrum sharing a-mong multi-systems and increase the total transmission rate.%现有的OFDMA资源分配算法大都以提高单系统内的频谱利用率为目标,而对于同一区域内多系统间的资源共享问题未加考虑.针对这一问题提出了一种适用于双无线系统的半静态的资源分配策略.首先划分一定的频谱共享区并设置系统间的优先级,然后引入一种泊松评判机制来控制不同系统接入频谱共享区的概率,从而降低系统间的互干扰.结合几种分配算法的仿真结果表明:这种资源分配策略可有效实现多系统间的频谱共享,提高总的传输速率.
摘要：介绍了空间智能系统的国内外最新研究成果,指出其与机器人智能系统有机结合的优势.其次,对国内外经典的基于智能空间的服务机器人智能系统研究实例进行分类介绍,指出二者结合中存在的问题和难点.%First,this paper summarizes the latest research achievements about smart space and points out the advantage of a combination of robot intelligent system and smart space.Subsequently,classic intelligent systems of service robots based on smart space in the world are introduced as a manner of classification.At last,the problems and difficulties of a combination of the two are showed.
摘要：With copper foils as substrates,large -area and continuous monolayer graphene films were synthesized by chemical vapor deposition under atmospheric pressure.The electrical detection of hydrogen peroxide based on graphene field - effect transistors indicated the electrical signals of graphene transistors were sensitivity to the hydrogen peroxide.Decoration of glucose oxidase on the surface of graphene film,the electrical detection of glucose showed that the modified graphene transistors had high sensitivity to glucose.The detection limitation can reach 0.1 mM with a high response speed.%以铜箔为衬底,采用化学气相沉积的方法制备大面积单层石墨烯薄膜并制备相应的石墨烯场效应晶体管,过氧化氢电子识别研究表明,石墨烯场效应晶体管的电性能对由过氧化氢产生的外来干扰非常灵敏.利用末端带有吡啶环功能基团的葡萄糖氧化酶对石墨烯场效应晶体管进行表面改性后,葡萄糖电子识别结果表明其器件对葡萄糖有非常灵敏的电子识别性能,其检测下限小于0.1 mM,且具有生物传感器响应快、稳定性好的特点.
摘要：提出了一种结合蜂窝和中继技术的两跳中继蜂窝系统结构用来增加系统容量和平衡流量负荷,并利用多维马尔可夫链建立了它的拥塞控制模型.然后在这个模型的基础上,分别得到了系统的平均下行传输速率和数据包呼叫请求阻塞概率.最后通过数值计算分析了各种系统参数对具有拥塞控制功能两跳中继蜂窝系统性能的影响.研究结果表明,与两跳中继蜂窝系统相比,具有拥塞控制功能的中继系统在提供相同平均下行吞吐量的同时,可以有效降低系统的呼叫请求阻塞概率.%To increase system capability and balance traffic loads,a new architecture of two-hop-relay cellular system is proposed with the integration of cellular and relaying technologies.Its congestion control model is built by use of multi-dimensional Markov chains.Based on this model,the average downlink transmission rate and the call blocking probability of packets can be obtained.Finally,the impact of various parameters on the performance of the two-hop-relay cellular system is analyzed through numerical calculation.Research results have shown that the two-hop-relay cellular system with congestion control can effectively reduce the call blocking probability with the same average downlink throughput.
摘要：在等离子体鞘套中激光成丝形成等离子体通道,该通道可以被等效为内部是低密度等离子体、外层为无限大厚底高密度等离子覆层的等离子体圆柱波导.分析了该模型下的传播特性,重点讨论了各类模式下的特征方程、截止的条件及波导的截止特性.%A plasma channel is generated by a laser beam in plasma sheath.The channel can be equivalent to a plasma cylindrical waveguide with its inner as an underdense plasma surrounded by an outer infinitive large high-density plasma cladding.The propagation characteristics of this model is analyzed.Emphasis is placed on the characteristic equation of different models,the cut-off conditions and the cutoff properties of the waveguide.
摘要：指出现有MIMO理论研究只是在所建立的基带数学模型基础上,依据空分复用(SDM)原理证明了MIMO可增加信道容量.但是它没有给出与该数学模型相适配的、合理的物理模型,导致所依据的SDM无法实现,使MIMO理论在数学层面所导出的信道容量公式在物理上是无法实现的.从天线的物理特性、各种天线阵的波束图、MIMO物理模型的不合理性、MIMO独立随机信道和SDM的不可实现性等诸多方面证明了MIMO理论的不可用性.并提出在Shannon公式应用原理和相控天线阵理论基础上构建的、用于取代MIMO系统的SHPCA系统,将利用SDM和Shannon公式应用方法给出获取该系统信道容量增益的原理、理论研究方法知模拟结果.%It is pointed out that the current MIMO theory bases its study solely on the established mathematical model,and using the space division multiplex (SDM) principle to provet the increase of channel capacity (CC).Unfortunately there is no reasonable physical model matching to that mathematical model,leading to the fact that the SDM cannot be realized in MIMO system.It implies that the CC formula of MIMO system deduced by the mathematical model cannot be realized physically.The infeasibility of MIMO theory is proved from multiple facets including the physical characteristics of antenna,radio beam patterns of many kinds of antenna array,the unreasonability of the MIMO physical model,infeasibilities of MIMO independent random channels and SDM.Based on the Shannon formula and the principle of phase-controlled antenna array,an SHPCA system is proposed to substitute the MIMO system.The principle and research method to obtain the gain of CC are given using the SDM and the application methods of Shannon formula.Simulation results are also provided.
摘要：ITU-T G.8032是目前电信级以太环网?；さ淖钪匾曜贾?其中地址刷新是ITU-T G.8032的关键技术之一.针对ITU-T G.8032地址刷新时会出现广播风暴的问题,提出了一种基于区域地址刷新的环网?；し桨?研究表明,基于区域地址刷新的方案能够抑制节点不必要的地址刷新动作,从而有效地提高了环网性能.%Ethernet technologies are rapidly becoming a dominant solution for carriers' networks. Ethernet ring protection switching, defined in ITU-T G. 8032 recommendation, provides a means to reliably achieve carrier-class network requirements for Ethernet topologies forming a closed loop. This article proposes an G. 8032 Ehernet Ring Protection ERP, using FDB flush based on area and explains how its automatic protection switching (APS) protocol works.