Current Issue : April - June Volume : 2013 Issue Number : 2 Articles : 6 Articles
We consider the problem of joint resource allocation and admission control in a secondary code-division network coexisting with a\r\nnarrowband primary system. Our objective is to find the maximum number of admitted secondary links and then find the optimal\r\ntransmitting powers and code sequences of those secondary links such that the total energy consumption of the secondary network\r\nis minimized subject to the conditions that primary interference temperature constraints, secondary signal-to-interference-plusnoise\r\nratio (SINR) constraints and secondary peak power constraints are all satisfied. This is an NP-hard optimization problem\r\nwhich motivates the development of suboptimal algorithms. We propose a novel iterative algorithm to solve this problem in a\r\ncomputationally efficient manner. Numerical results demonstrate that the proposed algorithm provides excellent solutions that\r\nresult in high energy efficiency and large admitted percentage of secondary links....
Pervasive healthcare and citizen-centered care paradigm are moving the healthcare outside the hospital environment. Healthcare\r\ndelivery is becoming more personalized and decentralized, focusing on prevention and proactive services with a complete view of\r\nhealth and wellbeing. The concept of wellness has been used to describe this holistic view of health, which focuses on physical,\r\nsocial, and mental well-being. Pervasive computing makes it possible to collect information and offer services anytime and\r\nanywhere. To support pervasive healthcare with wellness approaches, semantic interoperability is needed between all actors and\r\ninformation sources in the ecosystem. This study focuses on the domain of personal wellness and analyzes related concepts,\r\nrelationships, and environments. As a result of this study, we have created an information model that focuses on the citizens�\r\nperspectives and conceptualizations of personal wellness. The model has been created based on empirical research conducted with\r\nfocus groups....
Context aware communication services rely on information sources and sensors, to derive usersââ?¬â?¢ current situation and potential\r\nneeds, and to adapt their communication services accordingly. If extensive studies have been driven on context awareness by\r\nindustrials and researchers from academia, the design of such systems without modifying uses and manners of underlying\r\ncommunication servicesââ?¬â?while keeping them simple, intuitive, and reactiveââ?¬â?remains a challenge. In this work, we introduce\r\na context aware communication system that takes into account userââ?¬â?¢s preferences, workload, and situation to customize telephony\r\nservices. In this implementation, we use IMS for communication management. The benefits of this implementation are the\r\nenhancement of IMS with context awareness features, and the coupling of user preferences with contextual information to provide\r\nimproved service customization, without modifying the user experience....
The concept of cognitive radio (CR) focuses on devices that can sense their environment, adapt configuration parameters, and\r\nlearn from past behaviors. Architectures tend towards simplified decision-making algorithms inspired by human cognition.\r\nInitial works defined cognitive engines (CEs) founded on heuristics, such as genetic algorithms (GAs), and case-based reasoning\r\n(CBR) experiential learning algorithms. This hybrid architecture enables both long-term learning, faster decisions based on past\r\nexperience, and capability to still adapt to new environments. This paper details an autonomous implementation of a hybrid\r\nCBR-GA CE architecture on a universal serial radio peripheral (USRP) software-defined radio focused on link adaptation. Details\r\ninclude overall process flow, case base structure/retrieval method, estimation approach within the GA, and hardware-software\r\nlessons learned. Unique solutions to realizing the concept include mechanisms for combining vector distance and past fitness\r\ninto an aggregate quantification of similarity. Over-the-air performance under several interference conditions is measured using\r\nsignal-to-noise ratio, packet error rate, spectral efficiency, and throughput as observable metrics. Results indicate that the CE is\r\nsuccessfully able to autonomously change transmit power, modulation/coding, and packet size to maintain the link while a noncognitive\r\napproach loses connectivity. Solutions to existing shortcomings are proposed for improving case-base searching and\r\nperformance estimation methods....
This paper describes the design and prototype implementation of a communication platform aiming to provide voice and video\r\ncommunication in a distributed networking environment. Performance considerations and network characteristics have also been\r\ntaken into account in order to provide the set of properties dictated by the sensitive nature and the real-time characteristics of\r\nthe targeted application scenarios. The proposed system has been evaluated both by experimental means as well as subjective\r\ntests taken by an extensive number of users. The results show that the proposed platform operates seamlessly in two hops, while\r\nin the four hops scenario, audio and video are delivered with marginal distortion. The conducted survey indicates that the user\r\nexperience in terms of Quality of Service has obtained higher scores in the scenario with the two hops....
Recent growth and popularity of MANETs and their use in various settings has prompted new scenarios where secure and privacy-preserving networking operation is highly most important. Location information has recently become increasingly available through small and in expensive global positioning system (GPS) receivers, partially prompted by the emerging trend to incorporate location-sensing into personal hand-held and other wireless devices. Some loopholes of Anonymous Location-Aided Routing in MANETS (ALARM) protocol come in focus. ALARM protocol does not the issues like adversaries that mount Denial-of-Service (DoS) attack by creating wormholes and other topological abnormalities. To compare the vulnerability effects of wormhole attack on the ALARM protocols against the attack, there is a need to address the location based protocols as well as the impacts of the attacks on the MANETs. In this paper we proposed to enhance security in ALARM protocol by Addressing Wormhole Attack along with analyzing the effects of Wormhole attack on basis of, Network load, throughput and Packet delivery Ratio in ALARM. We have simulated the Wormhole attack using Proactive routing protocols....
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