私有云PaaS部分关键技术问题分析

简要介绍运营商私有云PaaS特点、组成部分及发展现状,分析运营商在建设私有云PaaS过程中涉及到的几个关键技术问题,如总线设计、数据部署、安全认证等;分析了上层业务对PaaS的服务及安全需求,利用SOA、Web Services、数据库读写分离等技术给出合理解决方案,并详细描述了安全认证中2个重要流程：资源授权和应用访问。     

运营商私有云的DaaS构建方案初探

从分析运营商私有云中DaaS需提供的功能入手,详细介绍了DaaS的架构设计、部署方案,最后给出了DaaS的具体流程和组件设计。     

云计算服务等级协议（SLA）研究

以云计算服务等级协议SLA为研究对象,从云计算SLA的概念、需求以及云计算SLA所涉及到的参数等几个方面,对云计算服务等级协议SLA进行了研究和阐述。重点对目前常见的几种云计算服务所涉及的关键服务质量参数进行了分类阐述。     

云计算安全问题研究综述

最近,由于经济性和高质量服务,云计算成为业界关注的焦点。过去10年,云计算通过产品和服务与企业和个人的日常生活紧密相连。云计算按需付费的特点激励着企业主动上云,从2019年开始,全球企业开始大规模上云,目前这种趋势依然强劲。虽然云计算为企业和个人带来了很多好处,但直到今天,云安全仍是各个云服务提供商亟需解决的挑战。云计算技术中虚拟化、多租户、按需付费等特点也为恶意攻击者提供了入口和漏洞。基于过去云计算安全问题的研究成果,探讨云计算3层体系结构,即基础设施即服务、平台即服务和软件即服务的安全问题和应对策略,并提出未来发展建议。     

云计算在电信领域的应用

电信运营商面临着节能降耗、提升服务质量和业务创新的压力,云计算技术的出现为解决这些压力提供了新的思路。在基础设施层面,采用虚拟化技术能够有效提高资源利用率,提高系统的可伸缩性和可用性;在开发平台层面,电信网能够开放自身业务能力,为业务创新提供支持;在业务层面,电信网能够以服务的形式提供各类软件,开拓电信业务的范围。云计算同时也会带来安全、管理和标准等方面的问题,这些问题需要在发展中逐步解决。     

云计算安全浅析

云计算是近年来互联网讨论最为热烈的技术,被认为是互联网发展的趋势。随着云计算的深入应用,云计算安全问题成为最引人关注的焦点之一。本文结合云计算的特点,重点介绍了数据安全、应用安全以及虚拟化安全在云计算环境下面临的威胁以及相应的对策。     

云计算服务模型研究

美国国家标准技术研究院在《NIST的云计算定义》中提出了云计算的参考定义,明确了云计算的3种服务模型,即SaaS（软件即服务）、PaaS（平台即服务）和IaaS（基础设施即服务）。文章归纳了云计算3种服务模型的基本定义,列举了每种服务模型的代表性产品,分析了各类服务模型的主要优势,给出了每种服务模型的应用案例。     

基于云计算的无线城市平台的研究与设计

通过介绍云计算的相关背景提出了基于云计算的新一代业务运营支撑网的IT基础架构,在此基础上对基于云计算的无线城市方案进行了详尽地研究与设计,包括云硬件架构、云软件架构、云应用架构等,分析了云计算的竞争优势,基于云计算的架构将更有效支撑未来电信运营商业务的发展。     

基于云计算的电子商务平台搭建方案与分析

基于联通信息导航电子商务平台搭建需求,以云计算、移动互联网等新技术为手段,提出平台体系一级架构的演进方案。方案充分吸收了"门户经营、平台共享、开放合作"的总体现代电子商务平台建设思想,并对信息导航云平台的IaaS层、PaaS层、SaaS层以及统一门户做出具体分析。基于云计算的电子商务平台搭建,实现管理支撑能力集中和一点建设全网共享,能够有效整合现有网络资源、完善平台支撑能力、集中建设业务系统、推进业务集约化健康快速发展。     

基于IPv6的云计算平台关键技术研究与分析

云计算的发展对IPv6地址资源产生了极大需求,同时对IPv6部署也带来巨大挑战。文章首先分析IPv4业务平台向IPv6升级时遇到的主要问题和需要的修改细节,并针对应用、数据、操作系统、网络接入各个层面提出传统业务平台向IPv6升级的具体策略及注意事项;然后研究IPv6协议在云计算环境中的应用,从IaaS、PaaS、SaaS三个层面分析云计算平台向IPv6升级的具体策略及注意事项,帮助云计算平台实现支持IPv6协议的虚拟机,提供支持IPv6用户访问的云服务。     

空间互联网技术发展现状及趋势

空间互联网技术是人类进行航天测控、导航定位、远洋航行等空间应用的基础支撑,是实现全球互联互通的关键手段。首先介绍了空间互联网的概念及内涵、组成及结构、特点及优势等相关基础知识,接着总结了空间互联网的关键技术,然后阐述了空间互联网的发展现状和面临的问题,最后结合互联网技术发展趋势和航天应用的发展要求,对空间互联网技术的发展趋势进行了展望和预测。     

高速光纤综合通信网络平台研究

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。     

带SIR结构新型多枝节加载双频滤波器

本文在传统λ/4阶梯阻抗谐振器的基础上,提出了一种新型的宽带双频滤波器改进设计方案。改进的滤波器增加了传输零点,此传输零点能有效的改进通带的选择性和阻带特性,且上阻带带宽很宽。结构简单,在传统类似滤波器同谐振频率基础上有效缩小了尺寸,并且设计的滤波器通带的中心频率和带宽是完全独立可控,方便我们应用到实际。工作在4.1 GHz和6 GHz两个频段,3 dB相对带宽分别为7.2%和2.2%,实测和仿真吻合良好。     

1xEV-DO与HSPA无线接入技术对比

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。     

Towards Mobile Ubiquitous Service Environment

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.     

Graphene‐Based Nanomaterials: Synthesis,Properties, and Optical and Optoelectronic Applications

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.     

开放和分解OTN网络技术研究和分析

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。     

Rural broadband: Gaps,maps and challenges

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

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.     

Cospas–Sarsat LEO and GEO: Satellite distress and safety systems (SDSS)

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.