15,318 research outputs found

    A novel cross-layer framework for large scale emergency communications

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    This paper explores the problem of improving coverage and capacity of large-scale communication networks in disaster-struck areas. We propose a novel integrated dynamic cross-layer distributed energy aware emergency framework, E3F, that spans large geographical areas and variable time ranges. E3F enables adaptive storage, dynamic packet scheduling and utility driven forwarding that avoids congestion and energy depletion. Our extensive experiments with realistic traces show significantly improved energy efficiency and low overheads while maintaining high success ratios for both data dissemination and query answering

    Spectrum sharing models in cognitive radio networks

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    Spectrum scarcity demands thinking new ways to manage the distribution of radio frequency bands so that its use is more effective. The emerging technology that can enable this paradigm shift is the cognitive radio. Different models for organizing and managing cognitive radios have emerged, all with specific strategic purposes. In this article we review the allocation spectrum patterns of cognitive radio networks and analyse which are the common basis of each model.We expose the vulnerabilities and open challenges that still threaten the adoption and exploitation of cognitive radios for open civil networks.L'escassetat de demandes d'espectre fan pensar en noves formes de gestionar la distribució de les bandes de freqüència de ràdio perquè el seu ús sigui més efectiu. La tecnologia emergent que pot permetre aquest canvi de paradigma és la ràdio cognitiva. Han sorgit diferents models d'organització i gestió de les ràdios cognitives, tots amb determinats fins estratègics. En aquest article es revisen els patrons d'assignació de l'espectre de les xarxes de ràdio cognitiva i s'analitzen quals són la base comuna de cada model. S'exposen les vulnerabilitats i els desafiaments oberts que segueixen amenaçant l'adopció i l'explotació de les ràdios cognitives per obrir les xarxes civils.La escasez de demandas de espectro hacen pensar en nuevas formas de gestionar la distribución de las bandas de frecuencia de radio para que su uso sea más efectivo. La tecnología emergente que puede permitir este cambio de paradigma es la radio cognitiva. Han surgido diferentes modelos de organización y gestión de las radios cognitivas, todos con determinados fines estratégicos. En este artículo se revisan los patrones de asignación del espectro de las redes de radio cognitiva y se analizan cuales son la base común de cada modelo. Se exponen las vulnerabilidades y los desafíos abiertos que siguen amenazando la adopción y la explotación de las radios cognitivas para abrir las redes civiles

    Political Endowments and Electricity Market Regulation in Turkey: An Institutional Analysis

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    Turkey has been going through a liberalization process in its electricity market over the last decade. So far, the regulatory content of the market reforms has been in the center of attention in the literature, to the negligence of regulatory governance. However, recent studies, which applied the theoretical insights of new institutional economics to utilities regulation, have demonstrated that political endowments of the country draw the boundaries to which extent such regulatory content can be effectively implemented. In line with these studies, this paper adopts an institutional approach and attempts to identify the political endowments of Turkey in order to further analyze whether the market reforms succeeded in bringing about sufficient checks to cure the institutional problems. In other words, the paper takes a picture of the overall regulatory arena. The results show that the current regulatory structure, especially government-regulator relations, fails to meet good regulatory governance criteria. The paper also provides some policy suggestions.electricity regulation; regulatory governance; institutions

    Information Technology as Coordination Infrastructure

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    Business information technology is traditionally viewed as information provision technology. In this view, organizations use their IT to implement databases that provide people with information when they want it. This view is persistent even though information provision is never an end in itself but always has the further purpose to support the coordination of activities of people. The role if IT as coordination technology became more prominent in the 1980s with the advent of network technology, that allowed activities across different businesses to be coordinated. This trend has accellerated since the growth of Internet usage, and today IT is used to support an increasingly varied range of processes performed by a variety of partners that do not all have a hierarchical relation to each other. This makes it difficult to analyze requirements for IT support and specify IT solutions: Business processes may not be well-defined, and interests of different businesses may clash. This report argues that to deal with this in requirements engineering and IT solution specification, business information technology should not be viewed as IT support for business processes but as IT support for the coordination of activities in one or more businesses. We will identify three basic coordination mechanisms, namely coordination by price, by management, and by shared norms, and for each of these mechanisms, we will identify requirements for IT support. The advent of flexible and standardized networking technology has facilitated the creation of novel coordination mechanisms within these three general paradigms, and we will give an inventory of generalized coordination mechanisms made possible by current IT. Finally, we will draw conclusions for requirements engineering methods for IT support for each of the coordination mechanisms identified by the framework
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