总线接口芯片PC19054及其在高速数据采集系统中的应用

本文介绍了PCI总线接口芯片PCI9054的性能、总线操作及其DMA数据传输方式,并且通过它在高速数据采集系统中的应用实例,阐述了PCI9054在PCI接口电路设计中的简便性和实用性     

总线接口芯片PCI9054及其在高速数据采集系统中的应用

本文介绍了PCI总线接口芯片PCI9054的性能，总线操作及其DMA数据传输方式，并且通过它在高速数据采集系统中的应用实例，阐述了PCI9054在PCI接口电路设计中的简便性和实用性。     

高速数据传输卡用PCI 9054总线控制器

介绍了一种基于PCI总线的数据传输卡的实现方案,应用PCI 9054总线控制器实现PCI总线接口,分析了PCI 9054的工作性能     

高速数据传输卡用PCI9054总线控制器

介绍了一种基于PCI总线的数据传输卡的实现方案,应用PCI9054总线控制器实现PCI总线接口,分析了PCI9054的工作性能。     

基于CPCI总线的多中断接口控制的设计与实现

本文在介绍PCI/CPCI总线和PCI9054接口控制器的基础上,用可编程逻辑设计出了基于PCI总线结合PCI9054本地中断触发机制的多中断响应控制,从而实现了PCI9054本地总线与外围设备间的实时通信和数据传输.     

基于PCI总线的DDS AD9854异步控制的设计与实现

介绍了一种通过PCI总线控制器PCI9054对异步器件进行访问控制的方法。首先分析了PCI9054的目标传输时序以及DDS芯片AD9854的主要特性，然后采用FPGA器件，进行时序转换，完成了PCI9054对DDS器件I／O口的异步读写操作。     

PCI9054接口芯片的应用设计

PCI9054是美国PLX公司生产的PCI总线通用接口芯片．介绍了PCI总线接口的一般设计方法及PCI9054的内部结构、以及其工作原理,并以一种基于PCI总线的数据传输系统的设计为例,给出其工作原理,并讨论接口的硬件实现方法以及采用软件包Windriver开发设备驱动程序的方法．     

基于PCI总线的图像处理及传输系统的设计

PLX公司的PCI 9054是一种通用的PCI总线接口芯片,可方便地进行软硬件开发实现PCI总线桥接。介绍了利用PCI 9054开发的图像处理及传输系统和配套的WDM驱动程序,以FPGA为系统硬件框架核心,从接口LVDS和RS 422读入图像数据及其他同步帧数据,经过处理后通过PCI接口芯片及PCI驱动程序进行与计算机系统的数据交换,从而实现基于PCI总线的高速图像传输处理。利用PCI 9054开发PCI高速数据传输系统具有较好的性价比。     

基于CPCI总线的多DSP共享总线系统的设计与实现

Compact PCI/PCI总线是一种高速的,独立于CPU的总线结构,其本地总线接口逻辑的设计是应用Compact PCI/PCI总线开发高性能数字通信产品的难点。提出了一种基于PLX公司的桥接芯片PCI9054实现多DSP与CPCI总线连接的方法,并详细说明了PCI9054主从模式的操作过程。这种带有标准总线的通用处理系统,可以方便地利用大量面向标准总线的板卡,易于组建通用的DSP并行处理系统,其特点是应用领域广、可升级能力强、使用方便。     

基于PCI9054的接口卡

PCI9054是PLX公司生产的桥接PCI总线与本地总线的接口器件.在PCI9054的结构性能、数据传输模式及总线工作方式等特性的基础上,给出以PCI9054作为接口器件的接口板的硬件设计方案,并借助Windriver,ISE等工具用VHDL及 C 语言实现了逻辑和驱动开发.该接口卡已通过实践验证,能极好对外部设备进行工作模式和状态检测.     

作战中舰载雷达干扰装备的作战使用时机

作战使用时机决策是舰载有源、无源干扰使用的基本前提。结合相关电子对抗战术理论，通过建模分析，得出了有源压制式干扰和欺骗式干扰、无源冲淡式干扰和迷惑干扰的使用时机，探讨了伪装雷达幕的作战使用。其结论对有、无源干扰装备的作战使用决策具有重要的指导意义。     

一种多进程系统用例模型的逆向生成方法

用例模型是展现程序系统级行为的有效手段.文章针对具有并发特征的面向对象软件系统提出了一种多进程系统用例模型的逆向生成方法.该方法以进程为单位对目标系统的动态信息进行组织,使用单进程系统用例模型的逆向生成方法抽取出每个进程相应的用例模型,然后对具有相同进程名的不同进程的用例模型进行叠加,从而实现了多进程系统的用例模型的逆向生成.通过实验研究,表明该方法在恢复多进程系统的用例模型方面是有效的.     

Exploring the relations of subjective and objective Instagram use on young adults' mental health

We collected objective digital trace Instagram use data and subjective self-report use data to investigate relations with self-reported self-esteem, loneliness, body satisfaction, and depression among 192 young adults (ages 18–25). To our knowledge, this work is among the first of its kind to include both self-report data and digital trace data to understand similarities and differences in how each relates to aspects of users’ mental health. We measured and coded for both active and passive social media use. For objective passive Instagram use, results showed a negative relationship with loneliness and depression, and a positive relationship with body satisfaction and self-esteem. Subjective passive use, however, was related positively to depression. Subjective active use was also positively related to depression. We discuss the implications of these findings, given the observed differences in the relationships as a function of the type of Instagram use measurement.     

Conceptualizing the impact of information and communication technology on individual time and energy use

The energy requirements of everyday activities such as housework, travel or sleep differ considerably; hence, individual time use – the pattern of activities individuals perform during a day – is crucial for the energy consumption associated with lifestyles. Increasing use of information and communication technology (ICT) in everyday life changes individual time use and thus affects the associated energy requirements. ICT can have increasing or decreasing effects on energy use (e.g. it can reduce transport through virtual mobility or increase transport by creating the desire to travel to places seen on the Internet). Understanding the causal relationships between ICT, time, and energy use is essential to promote its desired impacts and prevent socially and environmentally unfavorable (unsustainable) ones. Despite various approaches to time use across disciplines, no consistent conceptual framework of the impact of ICT on time use and environmental impact exists so far. In this paper, we review existing literature on (1) ICT impacts on time use, and (2) environmental impacts of time use. Aiming to bridge differences across disciplines and methodological approaches, we develop a conceptual framework for systematically assessing the impact of ICT on time and energy use. The core of this framework is the categorization of ICT impacts on the relaxation of time and space constraints to activities, parallelization, fragmentation, substitution, avoidance, and delegation of activities, changes to the duration and manner of activities, changes to the process of activity planning, and generation of new ICT-based activities. In a broader systems perspective, these effects also trigger causal chains which can form feedback loops and thus change time-use patterns with some delay (systemic effects). Changes in time use affect direct energy requirements through the energy used to perform activities (e.g. in the form of electricity or fuels). Indirect energy requirements, the energy embedded in goods, only change if production of goods can be avoided (e.g. if telecommuting leads to fewer cars being purchased). The net energy impact of a given ICT use case depends on direct and indirect energy requirements of the activities performed before and after adoption of the use case. We demonstrate the application of the framework by qualitatively assessing time and energy use impacts of a frequently discussed ICT use case: telecommuting.     

Do educational inequalities affect Internet use? An analysis for developed and developing countries

This study investigates whether the existence of educational inequalities at the country level affects Internet use. Additionally, we explore the extent to which these impacts depend on countries’ economic development levels. We use a logit model and data set of 69 high- and middle-income countries for the period 2005–2015. We find a negative relationship between Internet use and education inequality for the whole sample. The results confirm that, in addition to the level of education and other socioeconomic variables, the distribution of formal education among citizens within a country is also important to explain Internet use. We also obtain that this distribution affects Internet use to a higher extent in middle-income economies in comparison with high-income ones. Unlike the positive influence of educational levels obtained in the academic literature, the existence of within-country educational disparities negatively influences Internet use. This study demonstrates the influence of countries’ educational structure in relative terms in explaining Internet use.     

敏捷开发过程中的迭代策略分析

该文基于统一建模语言(UML)用例模型在描述系统的功能方面的特点结合敏捷开发过程中的迭代顺序,提出了以UML用例图中所包含的各个用例的风险和价值组合进行高低排序,从而决定敏捷开发的迭代顺序.这样做的一个明显好处就是能保证对高风险高价值的用例优先开发,使其在随后的各次迭代中都得到测试,从而提高该用例的可靠性,进而提高整个系统的可靠性.     

Understanding the impacts of Internet use on senior Citizens’ social participation in China: Evidence from longitudinal panel data

Scholars have appealed to build a digitally inclusive society to include senior citizens. However, conclusions on the impacts of Internet use on senior citizens’ social participation are divided. In order to address the above issue, this study addresses two questions: 1) how Internet use is related to senior citizens’ social participation; and 2) what the specific impacts of Internet use are on different subgroups’ social participation. We aim to understand the specific impacts of Internet use on senior citizens’ social participation meanwhile explore the reasons causing the abovementioned inconsistence in prior studies. We ran different panel regression models to address these questions based on a dataset drawn from the China Health and Retirement Longitudinal Study. Our empirical results indicate that seniors who are Internet users have higher social participation than those who do not use the Internet even after controlling out other influencing factors; however, frequent Internet use leads to less social participation among senior citizens. For senior citizens with higher cognitive functioning, both using Internet or not and the frequency of Internet use lead to more social participation. Both using Internet or not and the frequency of Internet use cause senior citizens with pensions to engage in fewer social activities. For female senior citizens, frequent Internet use leads to lower social participation. These findings suggest that government and communities should improve digital infrastructures and offer senior citizens more opportunities to access the Internet; meanwhile, local communities, social workers, and family members should direct senior citizens to use the Internet in a reasonable manner.     

Adoption and Use of Computer-Based Voice Over Internet Protocol Phone Service: Toward an Integrated Model

This study examines factors influencing adoption and use of computer-based voice over Internet protocol (VoIP) phone service and attempts to integrate 2 theoretical approaches: the technology acceptance model (TAM) and the uses and gratifications framework. Using data from an online survey of VoIP users ( N = 420), structural equation modeling analyses revealed that perceived ease of use had a significant impact on perceived usefulness. In addition, perceived usefulness had a positive effect on actual VoIP use. The study further discovered that motivations for communication and instrumental use significantly affected perceived ease of use, perceived usefulness, and actual VoIP use. This study suggests that integration of TAM and uses and gratifications can be fruitful in understanding user acceptance of new communication technologies.     

CAD system use and engineering performance

Computer-aided design (CAD) systems can support engineering work at three levels: design, analysis, and communication. Seventy-five engineers in two gas turbine engine manufacturing companies were surveyed in an attempt to understand the relationship between these three types of CAD use and engineering performance. The results show strong links between different types of CAD use; use for design enables for for analysis, and 3-D system enables use of communication. Use of CAD communication features strongly relates to engineering performance. The results have implications for the design, implementation, management, and use of CAD systems     

Factors Influencing Strategic Use of Information Technology and Its Impact on Business Performance of SMEs

In this paper, we study the relationship between factors influencing the strategic use of IT and business performance by conducting a survey of small and medium‐size enterprises (SMEs). From the results of our survey we came to several conclusions which are presented here. First, IT investment has a significant impact on the strategic use of IT, and the strategic use of IT has a significant impact on business performance. Second, SME investment in IT and strategic use of IT are influenced by both the intensity of competition in the market environment and partnership with other organizations. Third, the support from the management group in SMEs is a core factor for IT investment and strategic use of IT. Finally, for SMEs to use IT strategically and successfully, it is necessary to combine members' participation with a flexible organizational structure and culture.