地理信息系统发展趋势及展望

介绍了地理信息系统（GIS）的发展趋势,包括从单机模式向网络模式GIS、从二维向三维甚至高维、从封闭系统到开放系统、从1S到3S甚至多S集成,最终是虚拟现实到数字地球,展望了未来GIS网络化、社会化、全球化、大众化的发展方向。     

Achieving limiting distributions for Markov chains using back buttons

As a simple model for browsing the World Wide Web, we consider Markov chains with the option of moving back to the previous state. We develop an algorithm which uses back buttons to achieve essentially any limiting distribution on the state space. This corresponds to spending the desired total fraction of time at each web page. On finite state spaces, our algorithm always succeeds. On infinite state spaces the situation is more complicated, and is related to both the tail behaviour of the distributions, and the properties of convolution equations.     

网络文明的社会追求——网络卫生的立法思考

互联网的高速发展 ,给人们的生活带来了极大的便捷 ,但同时也存在着诸如“垃圾邮件”和“黄毒网站”等负面问题。针对这些问题 ,世界各国都对计算机安全进行立法保护 ,我国也进行了一系列立法工作 ,打击计算机犯罪。但目前仍存在一些空白区域 ,特别是在网络卫生方面。因此 ,有必要专门制订一部《网络卫生法》。     

企业战略联盟的动机、形态及其绩效的研究综述

企业间的战略联盟是市场的需要,也是企业自身发展的需要,对全球经济的发展具有重大意义。近年来,人们对企业战略联盟的研究热点主要集中在四个方面:第一,企业建立战略联盟的动机问题;第二,战略联盟治理结构问题;第三,企业形成战略联盟后的绩效问题;第四,嵌入社会网络的战略联盟研究。通过对上述四方面研究成果的疏理、归纳可以看出,联盟治理结构(形态)和联盟绩效问题是战略联盟研究领域中的焦点,其中不仅涉及联盟绩效的度量、影响因素等,还涉及到联盟动机、形态和行为与绩效之间的关系等更深层次的问题。目前我国对企业战略联盟的理论研究和实践探索还处于起步阶段,有待我们进行深入地探讨。     

Capacity Planning and Allocation for Web‐Based Applications

Motivated by the technology division of a financial services firm, we study the problem of capacity planning and allocation for Web‐based applications. The steady growth in Web traffic has affected the quality of service (QoS) as measured by response time (RT), for numerous e‐businesses. In addition, the lack of understanding of system interactions and availability of proper planning tools has impeded effective capacity management. Managers typically make decisions to add server capacity on an ad hoc basis when systems reach critical response levels. Very often this turns out to be too late and results in extremely long response times and the system crashes. We present an analytical model to understand system interactions with the goal of making better server capacity decisions based on the results. The model studies the relationships and important interactions between the various components of a Web‐based application using a continuous time Markov chain embedded in a queuing network as the basic framework. We use several structured aggregation schemes to appropriately represent a complex system, and demonstrate how the model can be used to quickly predict system performance, which facilitates effective capacity allocation decision making. Using simulation as a benchmark, we show that our model produces results within 5% accuracy at a fraction of the time of simulation, even at high traffic intensities. This knowledge helps managers quickly analyze the performance of the system and better plan server capacity to maintain desirable levels of QoS. We also demonstrate how to utilize a combination of dedicated and shared resources to achieve QoS using fewer servers.     

医学讲授型多媒体网络课程的设计与开发

随着校园网在高校教育中的深入,讲授型多媒体网络课程在医学教育中发挥着越来越大的作用,本文从实践中总结了医学讲授型多媒体网络课程系统的结构及其核心授课录像的设计与制作。     

Virtual Teams versus Face-to-Face Teams: An Exploratory Study of a Web-based Conference System*

Many organizations are forming “virtual teams” of geographically distributed knowledge workers to collaborate on a variety of workplace tasks. But how effective are these virtual teams compared to traditional face-to-face groups? Do they create similar teamwork and is information exchanged as effectively? An exploratory study of a World Wide Web-based asynchronous computer conference system known as Meeting Web™ is presented and discussed. It was found that teams using this computer-mediated communication system (CMCS) could not outperform traditional (face-to-face) teams under otherwise comparable circumstances. Further, relational links among team members were found to be a significant contributor to the effectiveness of information exchange. Though virtual and face-to-face teams exhibit similar levels of communication effectiveness, face-to-face team members report higher levels of satisfaction. Therefore, the paper presents steps that can be taken to improve the interaction experience of virtual teams. Finally, guidelines for creating and managing virtual teams are suggested, based on the findings of this research and other authoritative sources.     

Multiple Conceptualizations of Small Business Web Use and Benefit*

Small businesses play an important role in the U.S. economy and there is anecdotal evidence that use of the Web is beneficial to such businesses. There is, however, little systematic analysis of the conditions that lead to successful use of and thereby benefits from the Web for small businesses. Based on the innovation adoption, organizations, and information systems (IS) implementation literature, we identify a set of variables that are related to adoption, use, and benefits of information technology (IT), with particular emphasis on small businesses. These variables are reflective of an organization's contextual characteristics, its IT infrastructure, Web use, and Web benefits. Since the extant research does not suggest a single theoretical model for Web use and benefits in the context of small businesses, we adopt a modeling approach and explore the relationships between “context‐IT‐use‐benefit” (CIUB) through three models—partial‐mediator, reduced partial‐mediator, and mediator. These models posit that the extent of Web use by small businesses and the associated benefits are driven by organizations’ contextual characteristics and their IT infrastructure. They differ in the endogeneity/exogeneity of the extent of IT sophistication, and in the direct/mediated effects of organizational context. We examine whether the relationships between variables identified in the literature hold within the context of these models using two samples of small businesses with national coverage, including various sizes, and representing several industry sectors. The results show that the evidence for patterns of relationships is similar across the two independent samples for two of these models. We highlight the relationships within the reduced partial‐mediator and mediator models for which conclusive evidence are given by both samples. Implications for small business managers and providers of Web‐based technologies are discussed.     

An application of the nonprofit virtual accountability index: Accountability in sport for development and peace

In this research note, we examine web-based accountability practices of human service nonprofits. Data were collected directly from the organizational websites of an international sample of 532 organizations involved in operating sport for social change programs, more commonly known as the field of sport for development and peace. Websites were coded using the nonprofit virtual accountability index—a theoretically grounded and robust tool—to measure information and interactivity available for stakeholders across five dimensions of accountability. Analyses of variance and independent t-tests were used to test potential group differences based on geographical region, the thematic types of social change efforts, and the type of sport used to deliver programming. The results of this analysis highlight the critical importance of geographical location and other organizational variables for web-based accountability practices. Furthermore, the results allow nonprofit leaders to identify common areas in need of improvement for smaller and emerging nonprofits.