10,504 research outputs found

    A Survey on Communication Networks for Electric System Automation

    Get PDF
    Published in Computer Networks 50 (2006) 877–897, an Elsevier journal. The definitive version of this publication is available from Science Direct. Digital Object Identifier:10.1016/j.comnet.2006.01.005In today’s competitive electric utility marketplace, reliable and real-time information become the key factor for reliable delivery of power to the end-users, profitability of the electric utility and customer satisfaction. The operational and commercial demands of electric utilities require a high-performance data communication network that supports both existing functionalities and future operational requirements. In this respect, since such a communication network constitutes the core of the electric system automation applications, the design of a cost-effective and reliable network architecture is crucial. In this paper, the opportunities and challenges of a hybrid network architecture are discussed for electric system automation. More specifically, Internet based Virtual Private Networks, power line communications, satellite communications and wireless communications (wireless sensor networks, WiMAX and wireless mesh networks) are described in detail. The motivation of this paper is to provide a better understanding of the hybrid network architecture that can provide heterogeneous electric system automation application requirements. In this regard, our aim is to present a structured framework for electric utilities who plan to utilize new communication technologies for automation and hence, to make the decision making process more effective and direct.This work was supported by NEETRAC under Project #04-157

    Measuring internet activity: a (selective) review of methods and metrics

    Get PDF
    Two Decades after the birth of the World Wide Web, more than two billion people around the world are Internet users. The digital landscape is littered with hints that the affordances of digital communications are being leveraged to transform life in profound and important ways. The reach and influence of digitally mediated activity grow by the day and touch upon all aspects of life, from health, education, and commerce to religion and governance. This trend demands that we seek answers to the biggest questions about how digitally mediated communication changes society and the role of different policies in helping or hindering the beneficial aspects of these changes. Yet despite the profusion of data the digital age has brought upon us—we now have access to a flood of information about the movements, relationships, purchasing decisions, interests, and intimate thoughts of people around the world—the distance between the great questions of the digital age and our understanding of the impact of digital communications on society remains large. A number of ongoing policy questions have emerged that beg for better empirical data and analyses upon which to base wider and more insightful perspectives on the mechanics of social, economic, and political life online. This paper seeks to describe the conceptual and practical impediments to measuring and understanding digital activity and highlights a sample of the many efforts to fill the gap between our incomplete understanding of digital life and the formidable policy questions related to developing a vibrant and healthy Internet that serves the public interest and contributes to human wellbeing. Our primary focus is on efforts to measure Internet activity, as we believe obtaining robust, accurate data is a necessary and valuable first step that will lead us closer to answering the vitally important questions of the digital realm. Even this step is challenging: the Internet is difficult to measure and monitor, and there is no simple aggregate measure of Internet activity—no GDP, no HDI. In the following section we present a framework for assessing efforts to document digital activity. The next three sections offer a summary and description of many of the ongoing projects that document digital activity, with two final sections devoted to discussion and conclusions

    Determinants and impact of private sector investment in Malawi: evidence from the 2006 investment climate survey

    Get PDF
    Over much of the last two decades, the economy of Malawi has been characterized by economic turbulence and uncertainty that has done serious damage to the private sector. Rapid liberalization exposed an unprepared private sector to potentially damaging forces. This paper draws upon the most comprehensive enterprise survey carried out in Malawi in recent years to assess the current state of private sector investment. We find the following key results: (1) low labor productivity is explained primarily by lack inputs per worker, rather than insufficient capital employed; (2) foreign competition in either domestic or export markets encourages reinvestment of current earnings; (3) firms with monopoly power are less likely to invest in increased capacity; and (4) high interest rates encourage Malawian firms to invest incrementally and using retained profits.

    The investment climate and the firm : firm-level evidence from China

    Get PDF
    The importance of a country's"investment climate"for economic growth has recently received much attention. The authors address the general lack of appropriate data for measuring the investment climate and its effects. The authors use a new survey of 1,500 Chinese enterprises in five cities to more precisely define and measure components of the investment climate, highlight the importance of firm-level data for rigorous analysis of the investment climate, and investigate empirically the effects of this comprehensive set of measures on firm performance in China. Overall, their firm-level analysis reveals that the main determinants of firm performance in China are international integration, entry and exit, labor market issues, technology use, and access to external finance.Environmental Economics&Policies,Economic Theory&Research,Trade and Regional Integration,Health Monitoring&Evaluation,ICT Policy and Strategies
    • …
    corecore