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 - 7 of 7
  • 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 - Scopus: 24
    Resource Discovery in Grid Systems: a Survey
    (Inderscience Enterprises Ltd., 2010) Hameurlain, Abdelkader; Çokuslu, Deniz; Erciyeş, Kayhan
    Resource Discovery (RD) is one of the key issues in successful Grid systems. Yet, new methodologies for RD are constantly researched owing to the dynamicity, heterogeneity and large-scale characteristics of Grids. Recently, synergy and convergence between Grid, Agent and Peer-to-Peer (P2P) systems were pointed out clearly. This paper provides a survey and a qualitative comparison of the most promising approaches (P2P techniques and agent systems) for RD. Viability of Grid systems relies mainly on efficient integration of P2P techniques and mobile agent (MA) systems to bring scaling and decentralised control properties to Grids.
  • Conference Object
    Citation - WoS: 17
    Citation - Scopus: 30
    A Performance and Profit Oriented Data Replication Strategy for Cloud Systems
    (Institute of Electrical and Electronics Engineers Inc., 2017) Tos, Uras; Mokadem, Riad; Hameurlain, Abdelkader; Ayav, Tolga; Bora, Şebnem
    In today's world, tenants of cloud systems expect timely responses to queries that process ever-increasing sizes of data. However, most cloud providers offer their services without any performance guarantees to their tenants. In this paper we propose a data replication strategy that aims to satisfy performance guarantees for the tenant while ensuring profitability of the cloud provider. Our strategy estimates the response time of the queries, as well as the expenditures that affect the profitability of the cloud provider. The decision of whether to perform replication is determined by the fulfillment of these two criteria. Validity of the proposed strategy is provided by means of a simulation study.
  • Conference Object
    Citation - Scopus: 2
    Resource Allocation Algorithm for a Relational Join Operator in Grid Systems
    (Association for Computing Machinery (ACM), 2012) Çokuslu, Deniz; Hameurlain, Abdelkader; Erciyeş, Kayhan; Morvan, Franck
    Grid systems become very popular during the last decade because of their rapidly increasing computational capabilities. On the other hand, the advances on different domains cause enormous increase in the scale of the manipulated data. This issue augments the importance of distributed query processing and causes researchers to port their underlying environment onto the grid systems. However the dynamicity, heterogeneity and large scale characteristics of grid systems pose new problems for the distributed query processing domain. Resource allocation for query processing in grid systems is one of these problems, which attracts many researchers' attention. In this paper, we propose a new resource allocation algorithm for one relational join operator in a query considering characteristics of the grid systems. We provide theoretical analyses of the proposed algorithm and we consolidate analyses with the simulations. Copyright © 2012 ACM.
  • 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.
  • Conference Object
    Citation - Scopus: 3
    Grid Resource Discovery Based on Web Services
    (Institute of Electrical and Electronics Engineers Inc., 2009) Çokuslu, Deniz; Hameurlain, Abdelkader; Erciyeş, Kayhan
    The size of grid systems has increased substantially in the last decades. Resource discovery in grid systems is a fundamental task which provides searching and locating necessary resources for a given process. Various different approaches are proposed in literature for this problem. Grid resource discovery using web services is an important approach which has resulted in many tools to become de facto standards of today's grid resource management. In this paper, we propose a survey of recent grid resource discovery studies based on web services. We provide synthesis, analysis and evaluation of these studies by classification. We also give a comparative study of different classes proposed.
  • Conference Object
    Citation - WoS: 4
    Citation - Scopus: 6
    Robust Placement of Mobile Relational Operators for Large Scale Distributed Query Optimization
    (Institute of Electrical and Electronics Engineers Inc., 2007) Ergenç, Belgin; Morvan, Franck; Hameurlain, Abdelkader
    This paper presents a compile-time placement method of mobile relational operators MROs in a large scale environment. MROs are self adaptive to changing runtime conditions by deciding their execution place if they discover compile-time estimation errors. Proposed placement methods tend to have a main drawback with MROs running over a large scale environment: their focus is on finding optimal performance depending on single-point estimation at compile-time, instead of optimal performance over an estimation interval. We propose: (i) to determine the migration space of a MRO including the sites on which the MRO is allowed to migrate during its execution, and (ii) to find the robust site which will allow acceptable response time in an estimation interval. Performance study shows that, with a risk of loosing around 6% in response time, it is possible to gain up to 300% with the proposed robust placement.