Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Conference Object Citation - Scopus: 2Resource Allocation Algorithm for a Relational Join Operator in Grid Systems(Association for Computing Machinery (ACM), 2012) Çokuslu, Deniz; Hameurlain, Abdelkader; Erciyeş, Kayhan; Morvan, FranckGrid 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: 2A Maximum Degree Self-Stabilizing Spanning Tree Algorithm(Springer Verlag, 2010) Çokuslu, Deniz; Erciyeş, Kayhan; Hameurlain, AbdelkaderSpanning 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 - WoS: 4Citation - Scopus: 6Robust Placement of Mobile Relational Operators for Large Scale Distributed Query Optimization(Institute of Electrical and Electronics Engineers Inc., 2007) Ergenç, Belgin; Morvan, Franck; Hameurlain, AbdelkaderThis 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.