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Bandwidth‐ efficient space–time coded cooperation for resource‐constrained networks
Kim, Jee‐,Hoon,Vasilakos, Athanasios V.,Song, Hyoung‐,Kyu John Wiley Sons, Ltd. 2011 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.11 No.10
<P><B>Abstract</B></P><P>In cooperative transmission, cooperating nodes must hear the source messages first and forward it to the destination node with decodable composition of symbols. This restriction is one of big questions in cooperative networks since it decreases overall bandwidth‐efficiency. In this paper, we propose a scheme which alleviates it through novel use of dual carrier modulation (DCM) and an adequately designed distributed space–time block code (DSTBC). The proposed scheme achieves comparable error performance to the conventional one while providing 20% higher transmission rate. The performance is always guaranteed by the signal‐to‐noise ratio (SNR) based adaptive cooperation algorithm. Copyright © 2010 John Wiley & Sons, Ltd.</P>
Fair Power Control Using Game Theory with Pricing Scheme in Cognitive Radio Networks
Xianzhong Xie,Helin Yang,Athanasios V. Vasilakos,Lu He 한국통신학회 2014 Journal of communications and networks Vol.16 No.2
This paper proposes a payment-based power controlscheme using non-cooperative game with a novel pricing functionin cognitive radio networks (CRNs). The proposed algorithm considersthe fairness of power control among second users (SUs)where the value of per SU’ signal to noise ratio (SINR) or distancebetween SU and SU station is used as reference for punishmentprice setting. Due to the effect of uncertainty fading environment,the system is unable to get the link gain coefficient tocontrol SUs’ transmission power accurately, so the quality of service(QoS) requirements of SUs may not be guaranteed, and theexistence of Nash equilibrium (NE) is not ensured. Therefore, analternative iterative scheme with sliding model is presented for thenon-cooperative power control game algorithm. Simulation resultsshow that the pricing policy using SUs’ SINR as price punishmentreference can improve total throughput, ensure fairness and reducetotal transmission power in CRNs.
Security of Cached Content in NDN
Dohyung Kim,Jun Bi,Vasilakos, Athanasios V.,Ikjun Yeom IEEE 2017 IEEE transactions on information forensics and sec Vol.12 No.12
<P>In Named-Data Networking (NDN), content is cached in network nodes and served for future requests. This property of NDN allows attackers to inject poisoned content into the network and isolate users from valid content sources. Since a digital signature is embedded in every piece of content in NDN architecture, poisoned content is discarded if routers perform signature verification; however, if every content is verified by every router, it would be overly expensive to do. In our preliminary work, we have suggested a content verification scheme that minimizes unnecessary verification and favors already verified content in the content store, which reduces the verification overhead by as much as 90% without failing to detect every piece of poisoned content. Under this scheme, however, routers are vulnerable to verification attack, in which a large amount of unverified content is accessed to exhaust system resources. In this paper, we carefully look at the possible concerns of our preliminary work, including verification attack, and present a simple but effective solution. The proposed solution mitigates the weakness of our preliminary work and allows this paper to be deployed for real-world applications.</P>
Fair Power Control Using Game Theory with Pricing Scheme in Cognitive Radio Networks
Xie, Xianzhong,Yang, Helin,Vasilakos, Athanasios V.,He, Lu The Korea Institute of Information and Commucation 2014 Journal of communications and networks Vol.16 No.2
This paper proposes a payment-based power control scheme using non-cooperative game with a novel pricing function in cognitive radio networks (CRNs). The proposed algorithm considers the fairness of power control among second users (SUs) where the value of per SU' signal to noise ratio (SINR) or distance between SU and SU station is used as reference for punishment price setting. Due to the effect of uncertainty fading environment, the system is unable to get the link gain coefficient to control SUs' transmission power accurately, so the quality of service (QoS) requirements of SUs may not be guaranteed, and the existence of Nash equilibrium (NE) is not ensured. Therefore, an alternative iterative scheme with sliding model is presented for the non-cooperative power control game algorithm. Simulation results show that the pricing policy using SUs' SINR as price punishment reference can improve total throughput, ensure fairness and reduce total transmission power in CRNs.
Computation of an Equilibrium in Spectrum Markets for Cognitive Radio Networks
Sang-Seon Byun,Balashingham, Ilangko,Vasilakos, Athanasios V.,Heung-No Lee IEEE 2014 IEEE Transactions on Computers Vol. No.
<P>In this paper, we investigate a market equilibrium in multichannel sharing cognitive radio networks (CRNs): it is assumed that every subchannel is orthogonally licensed to a single primary user (PU), and can be shared with multiple secondary users (SUs). We model this sharing as a spectrum market where PUs offer SUs their subchannels with limiting the interference from SUs; the SUs purchase the right to transmit over the subchannels while observing the inference limits set by the PUs and their budget constraints. Moreover, we consider each SU limits the total interference that can be invoked from all other SUs, and assume that every transmitting SU marks the interference charges to other transmitting SUs. The utility function of SU is defined as least achievable transmission rate, and that of PU is given by the net profit. We define a market equilibrium in the context of extended Fisher model, and show that the equilibrium is yielded by solving an optimization problem, Eisenberg-Gale convex program. To make the solutions of the convex program meet the market equilibrium, we apply monotone-transformation to the utility function of each SU. Furthermore, we develop a distributed algorithm that yields the stationary solutions asymptotically equivalent to the solutions given by the convex program.</P>
A Survey of Security and Privacy Challenges in Cloud Computing
Yuhong Liu,Yan (Lindsay) Sun,Jungwoo Ryoo,Syed Rizvi,Athanasios V. Vasilakos 한국정보과학회 2015 Journal of Computing Science and Engineering Vol.9 No.3
While cloud computing is gaining popularity, diverse security and privacy issues are emerging that hinder the rapid adoption of this new computing paradigm. And the development of defensive solutions is lagging behind. To ensure a secure and trustworthy cloud environment it is essential to identify the limitations of existing solutions and envision directions for future research. In this paper, we have surveyed critical security and privacy challenges in cloud computing, categorized diverse existing solutions, compared their strengths and limitations, and envisioned future research directions.
A Survey of Security and Privacy Challenges in Cloud Computing: Solutions and Future Directions
Liu, Yuhong,Sun, Yan Lindsay,Ryoo, Jungwoo,Rizvi, Syed,Vasilakos, Athanasios V. Korean Institute of Information Scientists and Eng 2015 Journal of Computing Science and Engineering Vol.9 No.3
While cloud computing is gaining popularity, diverse security and privacy issues are emerging that hinder the rapid adoption of this new computing paradigm. And the development of defensive solutions is lagging behind. To ensure a secure and trustworthy cloud environment it is essential to identify the limitations of existing solutions and envision directions for future research. In this paper, we have surveyed critical security and privacy challenges in cloud computing, categorized diverse existing solutions, compared their strengths and limitations, and envisioned future research directions.