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)
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)
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)
—The Web Services Agreement specification defines a normative language to formulate Service Level Agreements and a basic protocol to come to 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)
In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t As part of the D-Grid initiative the C3Grid project provides a service(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)
As the Grid is becoming the day-today infrastructure for e-Science and e-Business, support is required for more complex and demanding application scenarios in which not just a single resource is required, but a set of resources with certain dependencies. Such workflows complicate the management of resources, especially in cases where they are offered by(More)