41,927 research outputs found

    Enhancing local-Transmitting less-Improving global

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    Super-resolving a natural image is an ill-posed problem. The classical approach is based on the registration and subsequent interpolation of a given set of low-resolution images. However, achieving satisfactory results typically requires the combination of a large number of them. Such an approach would be impractical over heterogeneous rate-constrained wireless networks due to the associated communication cost and limited data available. In this paper, we present an approach for local image enhancement following the finite rate of innovation sampling framework, and motivate its application to the super-resolution problem over heterogeneous networks. Local estimates can be exchanged among the nodes of the network in order to regularize the super-resolution problem while, at the same time, reduce data exchange

    Environmental data and indicators and human security related issues in Romania: an institutional approach

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    When the environmental issues are addressed in sustainability, human security terms the information demand is getting more complex, emphasising the need to integrate environmental, economic and socio-cultural information. This paper proposes an insight into the data and indicator issues on environment and human security in Romania from an institutional perspective. To a country in transition like Romania creating appropriate organisational structures and legislation has beed a prerequisite to building a realistic and effective environmental protection strategy. Therefore a presentation of the institutional and legislative framework of environmental protection created after 1989, in comparison with the situation in the communist period, has been considered necessary for understanding the institutional context of environmental data collecting, transmitting, processing and employing. On this basis the environmental information system has been critically assessed in terms of content, information flows and further developments related to human security issues. The data reliability at various territorial levels of data collecting, processing and transmitting has been also analysed in this context. A special emphasis has been put on the actors involved in employing the environmental information for strategy and policy elaboration and implementation, management and administration as well as for scientific research, environmental education and public participation purposes. A typology of these actors from organisational viewpoint has been proposed and analysed, pointing out the need of enhancing the netwotking effects at both national and international level.

    A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends

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    This paper examines the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state-of-the-art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. We also introduce the family of various jamming attacks and their counter-measures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.Comment: 36 pages. Accepted to Appear in Proceedings of the IEEE, 201

    Vehicle to vehicle (V2V) wireless communications

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    This work focuses on the vehicle-to-vehicle (V2V) communication, its current challenges, future perspective and possible improvement.V2V communication is characterized by the dynamic environment, high mobility, nonpredective scenario, propagation effects, and also communicating antenna's positions. This peculiarity of V2V wireless communication makes channel modelling and the vehicular propagation quite challenging. In this work, firstly we studied the present context of V2V communication also known as Vehicular Ad-hoc Netwok (VANET) including ongoing researches and studies particularly related to Dedicated Short Range Communication (DSRC), specifically designed for automotive uses with corresponding set of protocols and standards. Secondly, we focused on communication models and improvement of these models to make them more suitable, reliable and efficient for the V2V environment. As specifies the standard, OFDM is used in V2V communication, Adaptable OFDM transceiver was designed. Some parameters as performance analytics are used to compare the improvement with the actual situation. For the enhancement of physical layer of V2V communication, this work is focused in the study of MIMO channel instead of SISO. In the designed transceiver both SISO and MIMO were implemented and studied successfully

    An analysis on decentralized adaptive MAC protocols for Cognitive Radio networks

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    The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum and inefficiency in its utilization has been smartly addressed by the Cognitive Radio (CR) Technology which is an opportunistic network that senses the environment, observes the network changes, and then using knowledge gained from the prior interaction with the network, makes intelligent decisions by dynamically adapting their transmission characteristics. In this paper some of the decentralized adaptive MAC protocols for CR networks have been critically analyzed and a novel adaptive MAC protocol for CR networks, DNG-MAC which is decentralized and non-global in nature, has been proposed. The results show the DNG-MAC out performs other CR MAC protocols in terms of time and energy efficiency

    Enhancing coverage and reducing power consumption in peer-to-peer networks through airborne relaying

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    Application of ICT in Strengthening Health Information Systems in Developing Countries in the Wake of Globalisation.

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    Information Communication Technology (ICT) revolution brought opportunities and challenges to developing countries in their efforts to strengthen the Health Management Information Systems (HMIS). In the wake of globalisation, developing countries have no choice but to take advantage of the opportunities and face the challenges. The last decades saw developing countries taking action to strengthen and modernise their HMIS using the existing ICT. Due to poor economic and communication infrastructure, the process has been limited to national and provincial/region levels leaving behind majority of health workers living in remote/rural areas. Even those with access do not get maximum benefit from ICT advancements due to inadequacies in data quality and lack of data utilisation. Therefore, developing countries need to make deliberate efforts to address constraints threatening to increase technology gap between urban minority and rural majority by setting up favourable policies and appropriate strategies. Concurrently, strategies to improve data quality and utilisation should be instituted to ensure that HMIS has positive impact on people's health. Potential strength from private sector and opportunities for sharing experiences among developing countries should be utilised. Short of this, advancement in ICT will continue to marginalise health workers in developing countries especially those living in remote areas
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