Researcher:
Atsan, Emre

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Master Student

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Emre

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Atsan

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Atsan, Emre

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2006 - 200982010 - 20131

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Researcher Of Publications: search.filters.isAuthorOfPublication.29f11230-05f5-4a60-85d8-34a70eaeb827

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Now showing 1 - 9 of 9
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    Seed-based distributed group key selection algorithm for ad hoe networks
    (IEEE, 2007) N/A; Department of Computer Engineering; Atsan, Emre; Özkasap, Öznur; Master Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 113507
    Key establishment has a significant role in providing secure infrastructure for ad hoc networks. For this purpose, several key pre-distribution schemes have been proposed, but majority of the existing schemes rely on a trusted third party which causes a constraint in ad hoc platforms. We propose a seed-based distributed key selection algorithm, namely SeeDKS, for groups of nodes in ad hoc networks. Our approach is inspired by the earlier work on distributed key selection (DKS) and is based on the idea of common group key pool generated with group seed value for each different group. Simulation results show that using very small key ring sizes compared to DKS, we can achieve satisfactory results which DKS cannot accomplish in means of finding at least one common key among group members.
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    SCALAR: Scalable data lookup and replication framework for mobile ad-Hoc networks
    (IEEE, 2008) N/A; Department of Computer Engineering; N/A; Özkasap, Öznur; Atsan, Emre; Faculty Member; Master Student; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; 113507; N/A
    Data replication protocols proposed for MANETs are often prone to the scalability problems due to their definitions or underlying routing protocols they are based on. In particular, they exhibit poor performance when the network size is scaled up. However,scalability is an important criterion for several MANET applications. We propose a scalable and reactive data replication approach, named SCALAR, combined with a low-cost data lookup protocol. SCALAR is a virtual backbone based solution, in which the network nodes construct a connected dominating set based on network topology graph. Extensive simulations are performed to analyze and compare the behavior of this framework. It is demonstrated as an efficient solution for high-density, high-load, large scale mobile ad hoc networks.
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    Seed-based distributed group key selection algorithm for ad Hoc networks
    (IEEE, 2007) N/A; Department of Computer Engineering; N/A; Özkasap, Öznur; Atsan, Emre; Faculty Member; Master Student; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; 113507; N/A
    Key establishment has a significant role in providing secure infrastructure for ad hoc networks. For this purpose, several key pre-distribution schemes have been proposed, but majority of the existing schemes rely on a trusted third party which causes a constraint in ad hoc platforms. We propose a seed-based distributed key selection algorithm, namely SeeDKS, for groups of nodes in ad hoc networks. Our approach is inspired by the earlier work on distributed key selection (DKS) and is based on the idea of common group key pool generated with group seed value for each different group. Simulation results show that using very small key ring sizes compared to DKS, we can achieve satisfactory results which DKS cannot accomplish in means of finding at least one common key among group members.
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    SCALAR: scalable data lookup and replication protocol for mobile ad hoc networks
    (Elsevier, 2013) N/A; Department of Computer Engineering; Atsan, Emre; Özkasap, Öznur; Master Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 113507
    Data replication, as an essential service for MANETs, is used to increase data availability by creating local or nearly located copies of frequently used items, reduce communication overhead, achieve fault-tolerance and load balancing. Data replication protocols proposed for MANETs are often prone to scalability problems due to their definitions or underlying routing protocols they are based on. In particular, they exhibit poor performance when the network size is scaled up. However, scalability is an important criterion for several MANET applications. We propose a scalable and reactive data replication approach, named SCALAR, combined with a low-cost data lookup protocol. SCALAR is a virtual backbone based solution, in which the network nodes construct a connected dominating set based on network topology graph. To the best of our knowledge, SCALAR is the first work applying virtual backbone structure to operate a data lookup and replication process in MANETs. Theoretical message-complexity analysis of the proposed protocols is given. Extensive simulations are performed to analyze and compare the behavior of SCALAR, and it is shown to outperform the other solutions in terms of data accessibility, message overhead and query deepness. It is also demonstrated as an efficient solution for high-density, high-load, large-scale mobile ad hoc networks.
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    A classification and performance comparison of mobility models for ad hoc networks
    (Springer-Verlag Berlin, 2006) N/A; Department of Computer Engineering; Atsan, Emre; Özkasap, Öznur; Master Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 113507
    In mobile ad hoc network research, simulation plays an important role in determining the network characteristics and measuring performance. On the other hand, unrealistic simulation conditions may be misleading, instead of being explanatory. For this reason, constructing simulation models closer to the real circumstances is very significant. Movement behavior of mobile entities is one of the most important concepts for the realistic simulation scenarios in mobile ad hoc networks. In this study, we first provide a survey and a new hybrid classification of existing mobility models in the literature. We implemented the random direction and boundless simulation area models on Scalable Wireless Ad Hoc Network Simulator (SWANS) and conducted simulations of Ad Hoc On-Demand Distance Vector (AODV) protocol for these as well as the random walk and random waypoint models. Our comparative results for the mobility models are discussed on a variety of simulation settings and parameters.
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    Epidemic-based reliable and adaptive multicast for mobile ad hoc networks
    (Elsevier, 2009) Genç, Zülküf; Department of Computer Engineering; N/A; Özkasap, Öznur; Atsan, Emre; Faculty Member; Master Student; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; 113507; 108184
    An emerging approach to distributed systems exploits the self-organization, autonomy and robustness of biological epidemics. In this article, we propose a novel bio-inspired protocol: EraMobile (Epidemic-based Reliable and Adaptive Multicast for Mobile ad hoc networks). We also present extensive performance analysis results for it. EraMobile supports group applications that require high reliability. The protocol aims to deliver multicast data reliably with minimal network overhead, even under adverse network conditions. With an epidemic-based multicast method, it copes with dynamic and unpredictable topology changes due to mobility. Our epidemic mechanism does not require maintaining any tree- or mesh-like structure for multicasting. It requires neither a global nor a partial view of the network, nor does it require information about neighboring nodes and group members. In addition, it substantially lowers overhead by eliminating redundant data transmissions. Another distinguishing feature is its ability to adapt to varying node densities. This lets it deliver data reliably in both sparse networks (where network connectivity is prone to interruptions) and dense networks (where congestion is likely). We describe the working principles of the protocol and study its performance through comparative and extensive simulations in the ns-2 network simulator.
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    Epidemic-based approaches for reliable multicast in mobile ad hoc networks
    (Association for Computing Machinery (ACM), 2006) N/A; Department of Computer Engineering; N/A; N/A; Özkasap, Öznur; Genç, Zülküf; Atsan, Emre; Faculty Member; Doctor; Master Student; Department of Computer Engineering; College of Engineering; N/A; Graduate School of Sciences and Engineering; N/A; Koç University Hospital; N/A; 113507; N/A; N/A
    We present a classification of epidemic-based approaches utilized in the context of mobile ad hoc networks (MANET) with a focus on reliable multicast protocols. We provide a brief description of the other approaches to reliable multicasting in MANETs as well. Then, we describe our protocol, namely EraMobile, offering Epidemic-based Reliable and Adaptive Multicast for Mobile ad hoc networks. EraMobile's target is group applications requiring high-level of reliability and the protocol aims to provide fully reliable multicast data delivery with minimal network overhead even in the adverse network conditions. EraMobile utilizes an epidemic-based method in multicast operation to cope with dynamic and unpredictable topology changes arising from the mobility. Our epidemic mechanism does not require the maintenance of any tree- or mesh-like structure for multicasting. It also needs neither having global or partial view of the network nor having information of neighboring nodes and group members. Besides, it substantially minimizes the overhead incurred by eliminating redundant data transmissions. Another distinguishing feature of EraMobile is its capability of adapting to varying node densities in order to provide reliable data delivery in both sparse networks, where the network connectivity is prone to interruptions, and dense networks, where congestion is likely to occur. EraMobile is shown to achieve fully reliable multicast data delivery studied through extensive simulations by outperforming the other protocols compared, especially in terms of both packet delivery ratio and overhead efficiency.
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    Applicability of eigenvector centrality principle to data replication in MANETs
    (IEEE, 2007) N/A; Department of Computer Engineering; N/A; Özkasap, Öznur; Atsan, Emre; Faculty Member; Master Student; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; 113507; N/A
    An efficient data replication service is crucial for improving data accessability and resource utilization as well as providing consistency in mobile ad hoc systems. In this study, we investigate the applicability of eigenvector centrality (EVC) principle as an aid to determine replica nodes for data items in mobile ad hoc networks. There exist several studies for mathematical modeling of networks and defining roles to nodes based on EVC analysis in static networks. For MANETs, utilization of EVC to determine dissemination power of nodes has been also recently explored. In contrast to prior work, we focus on the question of whether EVC analysis can be helpful in locating nodes with replica roles. We present our approaches for connectivity matrix construction that is significant for precise EVC analysis. Comparative simulation results and analysis are described for both data replication and dissemination as a function of system scalability. Simulation results show that connectivity matrix construction techniques do not result in too much disparity for the performance of data replication and identifying one of the replicas to be the eigenvector central node does not lead to an improvement in data accessability for large networks.
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    Scalability analysis of data replication mechanisms in MANET
    (IEEE, 2007) N/A; Department of Computer Engineering; N/A; Özkasap, Öznur; Atsan, Emre; Faculty Member; Master Student; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; 113507; N/A
    In Mobile Ad-Hoc Networks service and data accessibility is lower than conventional static networks. Data replication is a technique that aims to increase accessibility by replicating copies of data in network nodes. In this paper, we defined the criteria for good replication schemes and analyzed the effects of increase in node size on performance of data replication techniques.