Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Now showing 1 - 4 of 4
  • Conference Object
    Citation - Scopus: 2
    Adaptive Join Operator for Federated Queries Over Linked Data Endpoints
    (Springer Verlag, 2016) Oğuz, Damla; Yin, Shaoyi; Hameurlain, Abdelkader; Ergenç, Belgin; Dikenelli, Oğuz
    Traditional static query optimization is not adequate for query federation over linked data endpoints due to unpredictable data arrival rates and missing statistics. In this paper, we propose an adaptive join operator for federated query processing which can change the join method during the execution. Our approach always begins with symmetric hash join in order to produce the first result tuple as soon as possible and changes the join method as bind join when it estimates that bind join is more efficient than symmetric hash join for the rest of the process. We compare our approach with symmetric hash join and bind join. Performance evaluation shows that our approach provides optimal response time and has the adaptation ability to the different data arrival rates.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 30
    Ensuring Performance and Provider Profit Through Data Replication in Cloud Systems
    (Springer Verlag, 2017) Tos, Uras; Mokadem, Riad; Hameurlain, Abdelkader; Ayav, Tolga; Bora, Şebnem
    Cloud computing is a relatively recent computing paradigm that is often the answer for dealing with large amounts of data. Tenants expect the cloud providers to keep supplying an agreed upon quality of service, while cloud providers aim to increase profits as it is a key ingredient of any economic enterprise. In this paper, we propose a data replication strategy for cloud systems that satisfies the response time objective for executing queries while simultaneously enables the provider to return a profit from each execution. The proposed strategy estimates the response time of the queries and performs data replication in a way that the execution of any particular query is still estimated to be profitable for the provider. We show with simulations that how the proposed strategy fulfills these two criteria.
  • Conference Object
    Citation - Scopus: 2
    A Maximum Degree Self-Stabilizing Spanning Tree Algorithm
    (Springer Verlag, 2010) Çokuslu, Deniz; Erciyeş, Kayhan; Hameurlain, Abdelkader
    Spanning trees are fundamental topological structures in distributed environments which ease many applications that require frequent communication between nodes. In this paper, we examine and compare two spanning tree construction algorithms which rely on classical and self stabilization approach. Then, we propose a new self-stabilizing spanning tree construction algorithm which uses maximum degree heuristic while choosing the root node. We show experimentally that our new algorithm provides smaller tree diameters than the two existing approaches with favorable run-times. © 2011 Springer Science+Business Media B.V.
  • Article
    Citation - WoS: 24
    Citation - Scopus: 31
    Dynamic Replication Strategies in Data Grid Systems: A Survey
    (Springer Verlag, 2015) Tos, Uras; Mokadem, Riad; Hameurlain, Abdelkader; Ayav, Tolga; Bora, Şebnem
    In data grid systems, data replication aims to increase availability, fault tolerance, load balancing and scalability while reducing bandwidth consumption, and job execution time. Several classification schemes for data replication were proposed in the literature, (i) static vs. dynamic, (ii) centralized vs. decentralized, (iii) push vs. pull, and (iv) objective function based. Dynamic data replication is a form of data replication that is performed with respect to the changing conditions of the grid environment. In this paper, we present a survey of recent dynamic data replication strategies. We study and classify these strategies by taking the target data grid architecture as the sole classifier. We discuss the key points of the studied strategies and provide feature comparison of them according to important metrics. Furthermore, the impact of data grid architecture on dynamic replication performance is investigated in a simulation study. Finally, some important issues and open research problems in the area are pointed out.