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一个快速的字符串模式匹配改进算法 总被引:1,自引:3,他引:1
在分析了BM算法以及一些重要的改进算法的基础上,提出了一种新的改进算法——BMG算法。该算法结合了BMH算法和BMHS算法的优点,同时考虑了字符串后一位字母的唯一性,提高了最大位移m+1的出现概率,有效地加快了匹配速度。BMG算法已经通过实验测试,并证明是有效的,测试结果表明该算法比BM、BMH、BMHS算法有更好的性能。 相似文献
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几种适用于水声信道的常模类盲均衡算法研究 总被引:2,自引:0,他引:2
对比研究了3种常模类盲均衡算法在水声信道均衡中的收敛性能,这些算法包括传统的常数模算法、归一化常数模算法和解相关常数模算法。通过仿真对各算法性能进行了分析。仿真结果表明,在算法剩余均方误差非常接近的情况下,解相关常数模算法和归一化常数模算法快于传统的常数模算法。 相似文献
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为了提高个性化推荐系统中模型描述的准确性,提出了一种改进的入侵野草优化算法。该算法将野草算法和混合遗传算法有机地结合,旨在克服传统野草算法过旱收敛、易于陷入局部优化的不足。最后,计算机仿真结果表明了所提出的算法明显优于其他常见的建模算法。 相似文献
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无线传感器网络(Wireless Sensor Network, WSN)定位问题可以看作一个目标函数最优化问题,通过鸡群优化算法进行求解。传统的鸡群定位算法所用的目标函数只考虑了待定位节点和参考节点之间的测量距离,测量距离不完整限制了定位精度的提高。基于此提出了一种鸡群协同定位算法,首先改进目标函数,确保待定位节点之间的测量距离被充分使用;然后采取多维标度(Multidimensioal Scaling, MDS)方法提供的良好初始位置,从而提高定位算法的收敛速度。仿真实验结果表明,与传统鸡群定位算法、粒子群定位算法、灰狼定位算法和改进的鸡群定位算法相比,鸡群协同定位算法能有效提高定位精度。另外,与传统的鸡群定位算法相比,虽然鸡群协同定位算法的时间复杂度有所增加,但定位性能得到了改善。 相似文献
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本文对基于 QR 分解的 LS 优化算法进行研究,通过构造矩阵的方法,优化 Q 矩阵和 R 矩阵的计算算法,实现了对 LS 算法的优化,减少了算法对时间和空间资源的需求,并对算法进行了时间复杂度和空间复杂度分析,证明了该优化算法的有效性。 相似文献
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基于Grid Of Tries的无冲突多维IP分类算法 总被引:1,自引:0,他引:1
快速IP分类算法是提高网络设备性能的关键,无冲突规则集则是正确进行IP报文分类的前提和保证、本文首先形式化描述了IP分类算法和规则冲突问题,介绍了常用的IP分类算法及冲突解决策略,并提出了一种基于Grid Of Tries的无冲突多维IP分类算法,解决了规则集中存在冲突的问题,最后对该算法进行了性能分析和展望。 相似文献
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随着网络的不断普及和发展,Internet为用户提供了一个极有价值的信息源。如何能够快速、准确的检索出用户感兴趣的信息,已经成为当前研究的热点。本文分析了KNN算法和聚类方法,指出了其中的不足并在此基础上提出了一种改进算法。该算法将聚类方法和KNN算法的优点结合起来,从而达到缩减了训练样本数量,减少了算法计算量,加快检索速度的目的。 相似文献
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现代通信网络应能满足各种通信业务和通信容量日益发展的需求,实现话音、数据、视频、IP等业务的一体化综合交换和传输。在比较TDM、IP和ATM三种协议的基础上,提出"采用内置RPR和MPLS功能的MSTP平台"建设光纤综合通信网络平台的实现方法。MSTP采用SDH的数据帧结构,保持了SDH标准光接口、灵活分插低速信号、自愈环保护和功能强大的网管等优点,可对TDM、IP和ATM协议进行优化传输。 相似文献
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HSPA与1xEV-DO具有相同的目的和基本相同的技术实现手段,本文主要对1xEV-DO与HSDPA从标准演进、关键技术、网络结构与性能、商用情况等方面进行了全面的对比分析。 相似文献
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Towards Mobile Ubiquitous Service Environment 总被引:2,自引:0,他引:2
JI Yang Zhang Ping Hu Zheng Wang Xu Li Yinong Tang Xiaosheng 《Wireless Personal Communications》2006,38(1):67-78
In this article we present a perspective on future vision of mobile communications and services which is referred to as Mobile Ubiquitous Service Environment (MUSE). Based on analysis of wireless communications and services, we exploit a conceptual model for MUSE via a top-down approach. The conceptual model consists of three major elements: Terminal Service Environment (TSE), Network Service Environment (NSE) and User Identity (UID). The concept of Always the Best Experience (ABE) is addressed as the hinge in design and development such that the user-centric services could be provided automatically and intelligently in the future diverse wireless world Based on these, we further discuss the issues on design and implementation of architecture of future wireless communication system. Requirements for architecture brought by the new features of MUSE are listed. Moreover, we also address several tradeoffs that should be taken into consideration in design. Finally, the deployment challenges for MUSE, such as reflectiveness of system, security and privacy, as well as peer-to-peer AAA are predicted.Ji Yang received PhD degree on Circuit and System, Bachelor degree on Telecommunication Engineering from Beijing University of Posts and Telecommunications (BUPT) in 2002 and 1993 respectively. Currently, he is an associate professor of BUPT, chief technical supervisor of Wireless Technology Innovation Institute, and vice manager of MTlab of Sino-Germany Software Institute. He leads the research on service and application in Future Forum in China. He also made much contribution to the China Communication Standardization Association (CCSA), including the vision of future Mobile Ubiquitous Service Environment, architecture of future B3G mobile terminal, etc. His research interests include architecture design for mobile ubiquitous networks, theory of self-organization, etc.Zhang Ping is now the professor of Beijing University of Posts and Telecommunications and director of Wireless Technology Innovation (WTI) Institute, BUPT. He has also served on the senior member of C3G Group, China MOST 863 future mobile communication FuTURE project, vice-chairman of China FuTURE Forum, and member of Vision Committee of World Wireless Research Forum(WWRF), he was vice chair of WWRF in 2005. He is also invited as the consultants for many domestic and oversea communication companies. He is very active on the international research activity on Beyond 3G area. He also participated in several European projects such as E2R and MOCCA. Until now, he has published 6 books, around 400 publications in journals and conferences in the area of telecommunications. His main research interests are theory and applications in wireless communication area. He was awarded by government, city of Beijing and Ministry of Information Industry several times for his great contribution to the industry and research activity in China.Hu Zheng is a PH.D candidate in mobile communications engineering in Wireless Technology Innovation Institute (WTI) at Beijing University of Posts and Telecommunications (BUPT). He received B.S degree from Nanjing University of Posts and Telecommunications in 2002, majoring in computer communications engineering. He currently works on serivce aspects of mobile ubiquitous communication system with focus on design and performance evaluation of interaction protocols and services in self-organized service environment.Wang Xu received the B.Tech. degree in electronic engineering from Beijing Polytechnic University (now named as Beijing University of Technology), Beijing, China, in 2002. Now he is working for his Ph.D. degree in Wireless Technology Innovation (WTI) Institute, Beijing University of Posts and Telecommunications (BUPT). His current interests include wireless communications in personal area, ad hoc networks and peer-to-peer system.Li Yinong received the BS degree major in Telecommunication Engineering in 1993 from Beijing University of Posts and Telecommunications, the MS degree and PhD degree major in Telecommunication and Electronic System in 1995 and 2003 from the Beijing University of Posts and Telecommunications. He is currently a lecture of STE (School of Telecommunication Engineering) of BUPT. His main research interests include service modeling, service composition approach, and intelligent service. In BUPT, he has given several lectures to both graduate and undergraduate students such as Information Theory, Speech Recognition, Pattern Recognition and Artificial Intelligence. 相似文献
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Graphene, a two‐dimensional, single‐atom‐thick carbon crystal arranged in a honeycomb lattice, shows extraordinary electronic, mechanical, thermal, optical, and optoelectronic properties, and has great potential in next‐generation electronics, optics, and optoelectronics. Graphene and graphene‐based nanomaterials have witnessed a very fast development of both fundamental and practical aspects in optics and optoelectronics since 2008. In this Feature Article, the synthesis techniques and main electronic and optical properties of graphene‐based nanomaterials are introduced with a comprehensive view. Recent progress of graphene‐based nanomaterials in optical and optoelectronic applications is then reviewed, including transparent conductive electrodes, photodetectors and phototransistors, photovoltaics and light emitting devices, saturable absorbers for ultrafast lasers, and biological and photocatalytic applications. In the final section, perspectives are given and future challenges in optical and optoelectronic applications of graphene‐based nanomaterials are addressed. 相似文献
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刘亚峰 《电信工程技术与标准化》2020,(11)
如何构建开放和分解的OTN网络,以实现跨厂家设备的混合组网和光层互连,一直是运营商和设备商追求的目标,ONF和LFN这两大开源项目组织分别基于各自的SDN控制平台——ONOS和OpenDayLight,给出了自己的解决方案——ODTN+TAPI和OpenROADM+TPCE,本文对这两种技术方案作了深入的研究和分析,比较了这两种技术的异同点,并对当前这两种技术的发展和应用前景作了简要的说明。 相似文献
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This paper examines challenges to evidence-based decision-making in the design and implementation of rural broadband investment programs. Our focus is on Canada, and the apparent need for further intra-rural broadband research and better data and mapping for informing public investment decisions, but similar challenges are evident in the international literature. Based on proprietary telecommunication provider datasets, the Canadian Radio-television and Telecommunication Commission (CRTC) estimates that broadband services with advertised speeds that meet its basic universal service targets (50 Mbps download and 10 Mbps upload) are available to 87.4 percent of households in Canada. In rural areas however, services that meet CRTC’s speed targets are available to 45.6 percent of households. Moreover, effective speeds and service quality levels that suppliers deliver and users experience tend to fall well below the government’s aspirational targets. In response to demand for better broadband, a variety of initiatives are directing public investment to the deployment of regional and rural broadband networks, which are typically owned and operated by private companies. There remains a serious lack of relevant data and its effective use in creating rural broadband strategies and managing public investment projects. Evidence from the literature suggest that this affects the degree and quality of geo-spatial and econometric analysis that results in a limited empirical basis to allocate scarce public investments, aggregate demand of consumers/communities, and assess the outcomes of rural broadband initiatives ex post. This paper provides a historical overview of rural broadband development in Canada and questions if the body of knowledge to inform public investment initiatives has grown sufficiently to ensure their effectiveness and sustainability. With a regional case from southwestern Ontario, Canada, we discuss the findings of the literature review, characterize the broadband data challenge, and discuss the importance of proprietary provider data cross-referenced with Internet user experience data. 相似文献
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The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation. 相似文献
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Cospas–Sarsat Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO) networks must provide enhanced service of Satellite Distress and Safety Systems (SDSS); to improve Search and Rescue (SAR) operations in all environments; and to increase safety and security at low cost for numbers of mobiles at sea, on land and in the air. This paper describes the concepts of integrated LEO and GEO space configurations in function of Cospas (space system for search of distress vessels and airplanes) and Sarsat SDSS, and SAR infrastructures. The paper also reviews satellite repeaters providing SDSS service for satellite beacons known as an Emergency Position Indicating Radio Beacons for Maritime, Personal Locator Beacons for land (road and rail), and Emergency Locator Transmitter (ELT) for aeronautical applications. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献