基于以太网的嵌入式系统网络接口模块设计及应用

嵌入式系统已经广泛应用在工厂自动化、测绘、水电、环保、国防等领域,但它们大都不具备网络互连能力,极大限制了设备使用、控制和数据交换性能,因而急需网络接口模块。结合最新计算机技术、网络技术、通讯技术,介绍了设计此嵌入式系统网络接口模块所需要的核心以太网控制器CS8900A,分析网络底层工作机理,采用高速高性能的C8051F005微控制器与以太网控制器CS8900A和接口芯片MAX232相连接实现网络接口模块设计,对接口电路作了详细的阐述,并对系统控制软件进行了具体的分析。该模块用途广泛,具有良好的应用前景。     

Speech as process: Effects of experimental design

The traditional design for the study of language variables is a controlled message design in which one kernel message is manipulated to produce message variations that represent the language variable contrasts. Thus message content is the same across treatment conditions and hence crossed with the treatment factors. Jackson and Jacobs (1983) criticized this design on three grounds. They argued that messages should be natural rather than contrived, that messages should be nested within treatment conditions rather than crossed with treatment factors, and that each study should use as many messages as possible. Their paper has been used by reviewers as the basis for rejecting studies done using the traditional design. This paper presents a detailed analysis of the arguments presented in Jackson and Jacobs (1983) as well as subsequent papers by Jackson (1984) and Jackson and Jacobs (1987). The arguments are shown to contain both methodological and substantive errors. When the arguments are corrected, it is shown that nested designs and multiple messages should be used only when absolutely necessary. It is the traditional controlled message, crossed design and not the naturalistic message, nested design which is robust; robust against not only incidental but fundamental confounding, robust against message by treatment by message interactions, and relatively robust against Type II error. Taken together with meta‐analysis, the traditional single message, crossed design can detect and identify message by treatment interactions. On the other hand, the multiple message design makes it impossible to identify such interactions.     

农家书屋研究进展

文章对农家书屋的研究进行文献统计分析,研究了文献的年度分布、作者分布、期刊分布及被引频次状况,并分阶段阐述了农家书屋的研究进展。     

高等教育统计信息化对策分析

针对高等教育统计信息化的重要性,分析了目前高等教育统计工作存在的各种问题,并就高等教育统计工作信息化建设问题进行探讨,且提出了相应的应对措施。     

基于图书馆基础架构的电子资源利用统计结构

简要分析评述国内外电子资源利用统计数据的获得方式，提出一种基于图书馆基础架构的电子资源利用统计系统结构，利用网关设计建立我国大学图书馆的电子资源利用统计机制。