Alexander Papaspyrou

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This paper empirically explores the advantages of the collaboration between different parallel compute sites in a decentralized grid scenario. To this end, we assume independent users that submit their jobs to their local site installation. The sites are allowed to decline the local execution of jobs by offering them to a central job pool. In our analysis(More)
The Web Services Agreement specification defines a normative language to formulate Service Level Agreements and a basic protocol to expose service-level descriptions, validate service-level requests, and come to an agreement. This protocol, often called “take-it-or-leave-it”, allows a service provider and a service consumer to decide whether(More)
Today's cloud ecosystem features several increasingly divergent management interfaces. Numerous bridging efforts attempt to ameliorate the resulting vendor lock-in for customers. However, as the number of providers continues to grow, the drawback of this approach becomes apparent: the need to maintain adapter implementations. The Open Cloud Computing(More)
In this paper, we address the problem of finding workload exchange policies for decentralized Computational Grids using an Evolutionary Fuzzy System. To this end, we establish a non-invasive collaboration model on the Grid layer which requires minimal information about the participating High Performance and High Throughput Computing (HPC/HTC) centers and(More)
The Cloud community is a vivid group of people who drive the ideas of Cloud computing into different fields of Information Technology. This demands for standards to ensure interoperability and avoid vendor lock-in. Since such standards need to satisfy many requirements, use cases, and applications, they need to be extremely flexible and adaptive. The Open(More)
The definition of a generic Grid scheduling architecture is the concern of both the Open Grid Forum’s Grid Scheduling Architecture Research Group and a CoreGRID research group of the same name. Such an architecture should provide a blueprint for Grid system and middleware designers and assist them in linking their scheduling requirements to diverse existing(More)
We present a negotiation and agreement strategy and protocol for the efficient scheduling of data intensive jobs in the Grid. It was developed with the background of the Collaborative Climate Community Data and Processing Grid (C3Grid), which provides a comprehensive infrastructure for solving computational problems in Earth System Science. The presented(More)
Grid computing is becoming a common platform for solving large scale computing tasks. However, a number of major technical issues, including the lack of adequate performance evaluation approaches, hinder the grid computing’s further development. The requirements herefore are manifold; adequate approaches must combine appropriate performance metrics,(More)
In this paper, we utilize a predator-prey model in order to identify characteristics of single-objective variation operators in the multi-objective problem domain. In detail, we analyze exemplarily Gaussian mutation and simplex recombination to find explanations for the observed behaviorswithin this model. Then, both operators are combinedto a new complex(More)