异构Web服务器集群的自适应成比例延时差异服务模型

随着Internet的迅速发展,Web服务在满足数量巨大而日益增长的社会需求中所起的作用越来越大,应用对Web服务器提出了更高的QoS(Quality of Service,服务质量)要求,特别是,要求其处理数量不断变更的用户访问,它们提出大量并发请求,并具有不同的QoS需求等.如何提高Web服务器QoS性能指标已成为当今研究的一大热点问题.本文提出一种成比例延时差异服务的异构Web服务器集群模型,该模型采用 : 队列模型刻划集群中各结点请求队列的请求到达和服务过程;在此基础上,提出两种基于反馈控制机制的请求派发自适应修正算法,每种算法均实现了相应的请求选择和派发策略.实验数据表明,本文所提出模型是适用于异构Web服务器集群的,两种请求派发自适应修正算法均能使异构Web服务器集群获得较好的服务质量(QoS)性能,具有较好的理论价值和应用前景.     

基于Linux的教学资源服务器构建

教学资源共享是信息化校园最主要的功能之一。基于Linux服务器平台,整合Web及FTP服务,设计教师账号及目录以配合权限控制,构建适用于教学的资源服务器,是实现这一功能的有效手段。利用FTP进行文件传输、Web服务器建立目录浏览界面,Quota控制磁盘空间分配,实现教学资源共享及学生作业上传两大功能。此外,通过Perl脚本语言,实现了用户账户创建及管理的自动化,以便日常维护。经过某院实际服务器长期稳定运行,证明了这一方案的有效性。     

Linux下基于TCP的预先派生子进程服务器的Socket编程

描述了客户/服务器模型以及常见的服务器类型——基于TCP的并发服务器。在一个基于TCP回射服务器程序的基础上,结合实际Web应用中的多进程服务器模型,考虑到原有的客户/服务器交互存在的问题,改进了客户程序,设计了实现并发功能的客户程序、并发服务器以及预先派生子进程服务器。在装有Linux的PC上分别进行客户程序和服务器程序的测试。实验结果表明:在与并发客户的TCP交互中,与并发服务器相比,预先派生子进程服务器能够及时处理新的客户连接,且响应时间减小到并发服务器的三分之一,达到了对服务器性能优化的目的。     

基于Android的嵌入式Web服务器设计

随着Internet技术的兴起,在嵌入式设备的管理与交互中,基于Web方式的应用成为目前的主流。本文主要论述了基于Android系统环境,在家庭网关中实现嵌入式Web服务器的设计方法,介绍了i-jetty嵌入式Web服务器,及其Web应用功能的实现。     

一种AJAX结合CGI的嵌入式瘦Web服务器的研究

针对AJAX与CGI的嵌入式瘦Web服务器软件结构,产生的HTML文件不易于维护和更新的问题,提出了建立一个AJAX处理机制结合CGI程序的嵌入式Web服务器软件结构.应用AJAX处理机制实现了客户端校验和客户端处理,以及无刷新访问服务器端资源.实现后的嵌入式Web服务器降低了嵌入式Web服务器开销的同时,使得页面文件易于维护和更新,是一种既降低成本又易于维护和更新页面文件的网络服务器设计方法.     

网络安全访问控制系统设计分析

普通Web网络安全访问控制系统不能随着并发用户数量的增加而降低平均响应时间和平均登录时间。为了解决此问题,设计基于大数据的Web网络安全访问控制系统。通过Web三级安全网络架构设计、大数据环境下系统PKI/CA模块设计、网络安全隔离模块设计,完成系统硬件设计;通过系统数据库设计、集中认证/授权模块设计、安全访问控制服务器设计,完成系统软件设计。实验结果表明,应用基于大数据的Web网络安全访问控制系统后,用户平均响应时间和平均登录时间得到有效控制。     

基于Web的油气资源评价软件实现

传统的油气资源评价软件以单机版为主,文中提出了基于Web的油气资源评价软件的主要架构,应用ExtJS技术、Ajax技术实现了基于Web的非参数发现序列评价软件及USGS非常规评价软件,并为多用户并发访问建立了多用户并发平台.基于Web的油气资源评价软件实现了将评价参数信息、评价计算及评价结果信息提交Oracle数据库,该研究为进一步开发油气资源评价软件打下了基础.     

一种家庭网络控制功能的设计与实现

本文主要介绍了基于嵌入式Web服务器的家庭网络网关的设计与实现,给出了该网关的软件结构框图,详述了基于嵌入式Web服务器的家电Internet控制功能的实现。该功能由IAC驻留进程(IAC Server)、Web服务器、通用网关接口CGI程序等模块支持。IAC驻留进程负责接收CGI程序发出的控制命令,并与网关主程序交互。Web服务器与CGI程序负责为客户浏览器提供静态、动态的Web页面。本文还着重阐述了嵌入式Web服务器、CGI、进程间通信等关键技术。     

嵌入式Web服务器的实现及其CGI应用

嵌入式设备资源有限,在这种情况下实现Web服务功能比较困难。针对嵌入式设备这种特点,本文通过比较几种Web服务器的优缺点,选定了Shttpd作为嵌入式Web服务器,并对其在Linux嵌入式平台下进行了移植。文中详细解析了CGI技术的相关原理,并结合HTML表单和CGI技术,给出了用C语言编写的基于CGIC库的串口程序,实现了客户端与服务端的动态交互。     

基于云计算的网络教学平台的设计与实现

在以浏览器和服务器为基础的前提之下,相关应用的程序和数据库存储功能都能在云计算模型服务器终端实现。本文在对云计算理论的研究过程中设计出了一个高校的教学平台,且云计算拥有并发计算和定制服务双重优点,对信息资源的整合优化起着重要的作用,而且基于网络学习策略基础之上将定制服务这一优点展现了出来。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

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.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.