Ioannis Kotsiopoulos

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The Grid's vision, of sharing diverse resources in a flexible, coordinated and secure manner through dynamic formation and disbanding of virtual communities, strongly depends on metadata. Currently, Grid metadata is generated and used in an ad hoc fashion, much of it buried in the Grid middleware's code libraries and database schemas. This ad hoc expression(More)
What is a Semantic Grid? The Grid aims to support secure, flexible and coordinated resource sharing through providing a middleware platform for advanced distributing computing. Consequently, the Grid's infrastructural machinery aims to allow collections of any kind of resources—computing, storage, data sets, digital libraries, scientific instruments,(More)
The increasing number of functionally similar services requires the existence of a non-functional properties selection process based on the Quality of Service (QoS). Thus, in this article, authors focus on the provision of a QoS model, an architecture and an implementation which enhance the selection process by the annotation of Service Level Agreement(More)
The Semantic Grid initiative aims to exploit knowledge in the Grid to increase the automation, interoperability and flexibility of Grid middleware and applications. To bring a principled approach to developing Semantic Grid Systems, and to outline their core capabilities and behaviors, we have devised a reference Semantic Grid Architecture called S-OGSA. We(More)
Moving towards a global market of services requires flexible infra-structures that will deal with the inevitable semantic heterogeneity that occurs during the negotiation that precedes the trading of a service. In order to reach an agreement, the negotiating parties need to understand the concepts describing the Quality of Service (QoS) terms which are part(More)
Grid resources such as data, services, and equipment, are increasingly being annotated with descriptive metadata that facilitates their discovery and their use in the context of Virtual Organizations (VO). Making such growing body of metadata explicit and available to Grid services is key to the success of the VO paradigm. In this paper we present a model(More)
—The paper explores the role of social media during large scale crises and disasters, as investigated by the COSMIC project. Based on a typology of crises and on case studies, we examine communication challenges and societal dynamics in conjunction with interactions among new media, officials and first responders, and the public. A number of technology(More)
The paper explores the role of social media during large scale crises and disasters, as investigated by the COSMIC project. Based on a typology of crises and on case studies, we examine communication challenges and societal dynamics in conjunction with interactions among new media, officials and first responders, and the public. A number of technology(More)
The evolution of services market raises the need for automatic support for negotiating service use criteria. In order to reach an agreement, the negotiating parties need to develop a common understanding of the Quality of Service (QoS) terms which are part of the Service Level Agreement (SLA). The use of semantic annotations together with reasoning can(More)