基于WWW的ASP聊天室实现原理

Ｉｎｔｅｒｎｅｔ是当前最热门的技术，作为网络信息交流最直接的手段之一，实时聊天室就显得特别的重要，服务器主动发送信息到客户端的聊天室耗费着大量的网络资源，这种现象会随着网络用户的增加而急剧恶化，采用分布式原理，把工作放在客户端，就能解决这个问题，从而大在减轻网络负担，优化网络性能，利用这一原理介绍采用微软ＡＳＰ技术如何去实现ＷＷＷ聊天室，讨论在聊天室中踢人、封锁ＩＰ地址、对话区滚屏等功能的实现方法     

基于J2ME的IMS客户端的设计与实现

IP多媒体子系统(IMS)是3GPP组织提出的一个水平应用平台,以满足统一、融合、有质量保证和开放的新一代多媒体应用和服务的需求.当前,IMS是下一代网络(NGN)最有竞争力的解决方案.本文提出了一个适应移动终端部署要求的基于J2ME、兼容3GPP、IETF和ETSI规范的IMS客户端.描述了该客户端的设计与实现.实现的客户端能够执行IMS会话、立即消息和呈现等应用客户端功能.     

网络安全计费管理策略研究

通过深入剖析了系统内核关于网络交通的控制原理,通过如下设计实现核心思想编写运行于工作站的注册请求软件(简称客户端)和运行于网关工作站的服务器软件(简称服务端);通过Socket套接字通信,服务端受到客户端的主动注册请求(以及核销、查询、修改私有信息等),并指示系统内核调度系统资源控制客户端所在工作站的出站通道,同时记录相关管理信息.     

基于一种远端执行模型的文档安全系统

针对现有DRM客户端易被破解和文档修改实时打包的难题,提出SC/SS(壳客户端/实体服务端)模型,基于数据流技术应用该模型能够实现客户端业务远端实时执行,通过客户端空壳化提高了防破解能力,同时解决了DRM文档修改实时打包的问题.对该模型电子文档系统的实现、应用进行了说明和描述,系统很好地提高了DRM系统客户端的安全性和灵活性.     

新技术下BT侵权的法律问题研究

一、DHT技术应用的背景 基于P2P技术的搜索方法总的来说可以分为两类:集中式和分布式.传统集中式BT技术的特点在于中心节点技术和种子文件的应用,但随着这项技术在法律上被宜告死亡,网络服务提供商不得不采用其他的替代技术,P2P技术搜索方法中的分布式方法(DHT技术)开始得到重视.DHT技术(英文全称为Distributed Hash Table)包括无结构化技术和结构化技术.无结构化的网络拓扑并不依据预先定义好的拓扑来构造严格结构的网络,因而无法保证搜索性能;而结构式可以保证搜索的正确性和完备性.分布式搜索方法真正地解决了"去中心化"的问题,通过应用DHT技术,网络中的任何一个客户端都实现服务器的部分功能,使得用户的下载不再依靠于中心服务器,从而实现真正的"点对点".     

第三方支付系统客户端的安全风险及防范机制

基于一个真实的资金诈骗案例,重点分析了第三方支付系统客户端存在的安全风险、攻击者所采用的攻击技术及其攻击原理.提出了技术防范机制来降低系统的安全风险,同时,建议通过用户方、第三方支付商、银行方及监管部门的共同努力,在最大程度上阻止类似的资金诈骗行为.     

OPC通信采集工业现场实时数据的实现

文章系统介绍了新精炼二级计算机的网络系统构成、相关工艺环节间的数据流程、数据传输、数据交换,通过介绍OPC技术的工作原理,从硬件配置到软件实现,结合OPC客户端的工作机制,介绍了L1与L2计算机数据交换的实现的解决方案,展示了三级计算机系统的作用。     

利用网络资源和跨文化交流,提高大学英语教学效果

以英语教学的实践为例,说明怎样在教学各个环节中,使用影视文件、屏幕演示、聊天室、BBS、E-mail等不同的多媒体或网络技术和手段,充分发挥多媒体或网络资源在大学英语教学中的作用,同时也从素质教育的要求出发探讨跨文化交流在英语课堂教学中的魅力,并倡导教师在英语教学时积极教授跨国文化知识,从而提高教学效果.     

分布式软件服务体系在企业中的应用

介绍了标准软件服务及客户端浏览器的实现原理，及其在企业中的应用。     

VPN技术在企业网络中的应用

随着企业网络技术的普及,员工需要随时随地联入企业网.随着企业本身发展壮大与跨国化,企业分支机构遍布世界.企业与各战略伙伴也需要随时通信.这涉及到远程安全接入企业网络.为了保证数据在网络传输时的安全,通常需要为每个分部建立独立的专用链路,这样就会造成投资大、工程难以实施.为了解决上述问题,采用了虚拟专用网(VPN,vitual private network)技术,即利用公共服务网络(如因特网)实现企业数据的安全通信和加密.     

A general procedure for locating and analyzing protein-binding sequence motifs in nucleic acids

In the last decade, two tools, one drawn from information theory and the other from artificial neural networks, have proven particularly useful in many different areas of sequence analysis. The work presented herein indicates that these two approaches can be joined in a general fashion to produce a very powerful search engine that is capable of locating members of a given nucleic acid sequence family in either local or global sequence searches. This program can, in turn, be queried for its definition of the motif under investigation, ranking each base in context for its contribution to membership in the motif family. In principle, the method used can be applied to any binding motif, including both DNA and RNA sequence families, given sufficient family size.     

基于VISUAL BASIC的圆盘拉伸工艺计算机程序设计

通过对一些圆盘拉伸工艺计算过程的分析 ,在充分比较各工艺计算模型的优缺点的基础上 ,选择了合适的工艺计算模型 ,并根据该模型的工艺计算原理和实际生产经验 ,以VisualBasic为前端开发平台 ,以Access2 0 0 0为后端数据库 ,编写了圆盘拉伸工艺工艺设计程序。该程序不仅界面美观 ,操作性强 ,参数修改方便 ,结果显直观 ,而且还运用多种方法处理和优化工艺 ,使设计结果能很好地符合生产实际。该程序可用于原有工艺的优化和新工艺和制订 ,具有一定的实用价值。     

在线氧含量监控系统在冷轧厂气保站的应用

针对武钢冷轧厂气保站氮气氧含量超标对产品质量的影响，确定了采用HM氧含量监控系统进行在线监控的技术方案，介绍了该系统的工作原理和具体实施方法。通过一年多的实际应用，取得了良好的应用效果与可观的经济效益。     

基于层次分析与模糊综合评判的回采方案优选

应用层次分析法与模糊数学原理,建立了某钨矿矿区回采方案的综合评判模型,科学合理地选出了该矿最优回采方案.在优选过程中,综合考虑影响回采方案的各项影响因素,利用层次分析法确定各评价指标的权重,并根据模糊数学原理对备选回采方案进行综合评判,得出各方案的优越度.实例计算结果得出2种方案综合优越度分别为0.791 0和0.748 1,因而确定方案1优于方案2.研究实例结果表明,该综合评判法可以对受多个定量和定性指标影响的决策进行有效的综合权衡分析,可为方案优选提供科学的指导.     

The effect of leg flexion angle on the mechanomyographic responses to isometric muscle actions

INTRODUCTION: An ROC analysis was carried out in order to determine the reliability of digital luminescence radiography review at a PC and this was compared with a radiological work station and with X-ray film on a viewing box. MATERIAL AND METHOD: 54 chest images obtained by digital luminescence radiography were selected, 31 of these contained small pulmonary nodules. In order to evaluate critical detail, five images of a phantom showing round foci were used. Five radiologists examined these, using a Siemens Magic View work station, a PC with proprietary software (ViewMed) and X-ray films on a viewing box. Image processing of the work station used the standard clinical application. ViewMed performs linear scaling of grey levels to 8 Bit. The results were examined statistically by means of a t-test. RESULTS: As far as the chest images were concerned there was no significant difference in the diagnostic value of these methods. There was, however, a highly significant loss of diagnostic information with respect to the round focus phantom when using the PC compared with the other methods. CONCLUSION: In the configuration in which it was used, the PC should not be relied on as a primary means of examination since critical details cannot always be seen. In routine use these play a subordinate role and there was no significant diagnostic loss where the chest images were concerned. We expect that by improvements in the frequency and contrast processing the PC accuracy will be considerably increased.     

三维激光扫描技术在地下巷道岩体结构面识别的应用

为了精确获取地下巷道的结构面信息,基于三维激光扫描技术,开展地下矿山巷道岩体结构面探测及识别研究.阐述了三维激光扫描系统及其原理、点云数据收集与处理、结构面信息提取的工作流程,并在云南锡业股份有限公司卡房分公司大白岩区域Ⅰ-51#矿群的1430 m、1440 m和1450 m水平主巷道开展了三维激光扫描与结构面信息提取...     

System for In-Service Strain Monitoring of Ordinary Bridges

An in-service bridge monitoring system (ISBMS) has been developed to provide near real-time web-based monitoring of live load strains in a bridge. The monitoring system is small, battery operated, can be rapidly deployed, and is programmed and interrogated via a user-friendly web interface. The ISBMS has been designed to be portable and used on an “as-needed” basis as a diagnostic tool or for health monitoring of ordinary bridges. The system is based on a small single-board computer with analog inputs; it also includes a cellular digital packet data modem for communication via the existing cellular network. Strains are measured using either a full bridge strain transducer or a quarter bridge foil strain gauge. The system has three modes of operation; The peaks program records peak live load strains that exceed a specified threshold, the time history program captures dynamic waveforms that exceed a specified threshold, and the rainflow program counts varying amplitude strain cycles. The selection and setup of the program, and retrieval of data is handled through a custom designed web interface. The system has been tested in the laboratory and in the field on a heavily traveled steel girder bridge. The data obtained from the ISBMS can be used for load rating using site specific data, fatigue investigations, monitoring bridge performance under permit loads, and as part of the biannual inspection of ordinary bridge.     

Caught in the web

The web is an exciting medium and if carefully used can provide a wealth of information; the sites described in this article are useful starting points. However, the process of getting the information down the telephone line can be time consuming. The collection of pictures for this article, for example, took one hour of surfing the web. However, such activity is fun, educational and when started becomes addictive.     

Transverse Analysis of Strutted Box Girder Bridges

The computer program STRUTBOX is presented for the transverse analysis of strutted box girder bridges, and particularly for bridges designed and constructed using the strutted box widening method. The program allows the deck prestressing and other reinforcing to be proportioned for transverse flexure, and the web stirrups and slab reinforcing to be proportioned for longitudinal shear and torsion. The program also gives an indication as to the severity of shear lag effects. The program is based on the folded plate method and is no more difficult to use than a plane frame computer program. The paper also demonstrates how the results given by a folded plate analysis can be approximated by using some simple membrane force equations in conjunction with a plane frame analysis. What is particularly interesting is that there is danger in using a plane frame analysis alone to approximate the results of a folded plate analysis for strutted box girder bridges (as well as other box girder bridges) because there are significant differences in the axial force diagrams given by the two methods.     

Weighting hidden Markov models for maximum discrimination

MOTIVATION: Hidden Markov models can efficiently and automatically build statistical representations of related sequences. Unfortunately, training sets are frequently biased toward one subgroup of sequences, leading to an insufficiently general model. This work evaluates sequence weighting methods based on the maximum-discrimination idea. RESULTS: One good method scales sequence weights by an exponential that ranges between 0.1 for the best scoring sequence and 1.0 for the worst. Experiments with a curated data set show that while training with one or two sequences performed worse than single-sequence Probabilistic Smith-Waterman, training with five or ten sequences reduced errors by 20% and 51%, respectively. This new version of the SAM HMM suite outperforms HMMer (17% reduction over PSW for 10 training sequences), Meta-MEME (28% reduction), and unweighted SAM (31% reduction). AVAILABILITY: A WWW server, as well as information on obtaining the Sequence Alignment and Modeling (SAM) software suite and additional data from this work, can be found at http://www.cse.ucse. edu/research/compbio/sam.html