基于PowerPC7447A处理器的通用处理模块设计

随着嵌入式系统的综合化、智能化发展,系统对数据处理能力的要求也越来越高。文章介绍了一种基于高性能处理器Power PC7447的通用处理模块的设计和实现,并对部分功能单元的设计进行了详细描述。该模块具有处理能力强、功能扩展性强、通用性强、集成度高等特点,具有较高的应用价值,目前该模块已经应用于多种嵌入式电子设备中。     

基于FPGA的PowerPC系统总线控制器设计与实现

Power PC处理器在机载设备数据处理中广泛应用,传统的Power PC总线控制器选用专用桥片实现。文章给出了一种基于FPGA的Power PC系统总线控制器的设计方法,详细介绍了系统架构及硬件实现,给出了逻辑设计时序。该架构已在机载设备中得到应用和验证。     

基于MPC866的虚拟多媒体控制板开发

本文介绍基于Power PC核的32位嵌入式RISC处理器MPC866来完成虚拟多媒体控制板的开发,实现了虚拟多媒体硬件设计的解决方案,并分模块给出了具体的硬件实现,给出了系统相互之间的接口,数据通信及与之相应的控制协议,以达到使多媒体控制板在系统中成为采集与处理服务器系统信息、通信联网以及故障定位和协调控制平台的设计目标。     

基于Power PC的处理器模块研究及故障分析

因升级性能好、功耗低等优点,Power PC系列处理器在多种领域被广泛使用,而在使用过程中,出现了各式各样的故障。文章通过介绍Power PC系列处理器工作原理、案例解剖、举例说明的方法来分析其常见的故障,以供研究。     

基于嵌入式系统和GPRS的热网换热站监控系统

提出了一种基于ARM系列的微处理器S3C4510B与GPRS模块构建的供热管网及换热站监控系统。介绍了系统的硬件构成及软件功能。监控单元的设计采用了高性能ARM处理器（S3C4510B）并移植了嵌入式操作系统μC／OSⅡ系统底层通信采用MODBUS协议。实际应用表明：该系统适应供热管网现代化管理发展的需求。     

基于ARM-LPC2210微处理器的最小系统设计

LPC2210是PHILIPS公司生产的基于一个支持实时仿真和跟踪的16／32位ARM7TDMI-S核的CPU。该系列芯片已经广泛地应用于各类嵌入式设备。介绍了LPC2210型ARM7微处理器和基于该处理器的最小嵌入式系统的硬件设计,采用模块化的设计方法,并给出了最小系统中电源、晶振电路、复位电路、存储器模块、JTAG、UART等各主要模块的外围应用电路及选型,最后给出简单的硬件调试方法。     

基于MPC8270的SPI驱动设计

介绍了嵌入式Power PC处理器MPC8270的体系架构和串行外设接口(SPI)控制器的工作原理。基于Vx Works和MPC8270嵌入式系统开发平台,详细介绍了MPC8270处理器芯片自带的SPI驱动程序的设计实现过程,描述了SPI的初始化、中断处理以及数据发送、数据接收等关键技术。基于MPC8270的SPI设计具有较强的实用性。     

基于NiosII片上可编程系统(SOPC)实现的雷达监控系统

介绍了一种基于NiosII嵌入式处理器实现的雷达监控系统,并详细说明了其可编程系统(SOPC)(system on programmable chip)的硬件构建过程和软件设计流程.本设计采用Cyclone II系列FPGA作为核心硬件,在FPGA上构建了基于高性能32位嵌入式NiosII处理器的片上SOPC;在NiosII IDE环境下开发出SOPC的应用软件.与传统的监控系统相比,本方案拥有更高的集成度、更快的数据传输速度,以及较小的体积和功耗.     

嵌入式GPRS通信模块开发研究

本文详细介绍了嵌入式GPRS通信模块的硬件设计和各部分的软件设计及实现。其中涉及了处理器UART的配置、通过串行口与GPRS模块连接进行收发数据的实现以及AT指令的介绍。     

基于单片机控制的人体感应报警器的研究

介绍一种利用热释电红外传感器进行监控,并进行报警的系统的设计。本设计包括单片机控制模块、快速报警模块、敏感红外探头模块、LED灯模块等部分组成。处理器用51系列单片机STC89C52。     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Molecular motor assembly of a biomimetic system

Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence