全球宽带电话市场分析

近两年．IP电话又叫网络电话的发展受到全球的关注。随着宽带接入的发展，基于宽带接入提供的网络电话具有了更大的生命力。从宽带电话的经营模式出发，探究这类业务的出现时现有话音业务市场的影响，进而分析这类业务的发展前景。     

Forming the optimal union of multiple databases

Many organizations, best illustrated by libraries, have access to hundreds of databases possessing varying degrees of complimentary and overlapping records. While users may receive positive marginal benefits from data duplications, all databases and their services cannot be supported because of resource limitations. This paper attempts to conceptualize the problem of database collection in an environment of multiple databases, with differential content and performance characteristics, diverse users, and limited resources. It defines the database collection problem as a constrained zero-one integer programming problem and solves for the optimal combination or union of databases. Several extensions are shown, where special conditions are imposed on the relationships between databases and/or their availability.     

聚醚型聚氨酯的氢键、微相分离及性能

用本体一步法合成了5种不同硬段含量(11.0％～46.9％)的二苯甲烷-4,4′-二异氰酸酯/环氧乙烷封端型聚环氧丙烷聚醚/乙二醇的聚醚型聚氨酯,并借助于IR,DSC,DMS和材料试验机等手段对该聚氨酯的氢键、微相分离及力学性能进行了表征。结果表明:随着硬段含量的增加,其>NH与微区中的>C=O的氢键化程度逐渐提高,软段微区中—O—的氢键化程度逐渐降低;微相分离程度逐渐提高;拉伸强度及硬度随之增加,扯断伸长率在硬段含量40％左右出现极大值。     

The Buck Stops Where?

SUMMARY

University students-whether adult, distance learner, or traditional age-need access to university services and quick accurate answers to their questions beyond traditional “business” hours. Students' busy schedules and changing life patterns dictate that university services meet their needs. At DePaul University in Chicago, student focus groups repeatedly pointed to the need for one central place to get an answer or solve a problem. DePaul Central was created as an information and referral service to satisfy that student need, at the same capitalizing on the value of the librarian skill set.     

软件类专业校企合作共建实训基地研究

从国家发展时工程型人才需求出发,分析了工程应用型人才培养的必要性,以及校企共建实训基地在工程应用型人才培养方面所起的作用.结合高校软件类专业工程应用型人才培养的现状、特点和要求,以及软件类专业实训基地的特点,提出了当前软件类专业校企合作实训基地的模式,探讨了建立校企合作实训基地必须要考虑和解决的问题.     

计算机端口和网络安全

该文介绍了一些与网络安全相关的计算机端口,并就如何通过这些端口的设置来提高计算机的网络安全性能进行了探讨,使网络运行环境更安全,更可靠。     

基于FX编程口的PC与PLC的通信

介绍了一种利用FX系列PLC的编程口,实现PC与PLC的通信的方法,着重介绍了FX编程口通信的通信协议、通信命令、通信传输的数据帧格式、PLC元件查询地址的编址、校验和的计算,并利用Windows环境下的开发软件VB6．0编写通信程序。     

用ActiveX控件实现PC与PLC之间的串行通信

可以用DLL（动态链接库）实现PC与PLC之间的通信。这种方法的主要问题是速率慢,效率低。讨论一种直接使用PC串口实现通信的方法,旨在调高通信速率。采用VB编程并且按照ActiveX控件标准封装,具有很好的移植性。     

基于Web Services系统登录日志的实现

目前高校内各部门的管理信息系统都拥有独立的记录登录日志和读取登录日志的模块,从而造成了业务逻辑的重复和数据的冗余。针对这种情况提出了一种基于WebServices的系统登录日志技术,使各异构系统能够统一调用登录日志的WebServices。这种方案充分利用了现有的网络资源,有效地避免数据与业务逻辑的冗余,实现了模块和数据的重用。