http://dl.gi.de/handle/20.500.12116/22143 2026-07-22T20:35:10Z http://dl.gi.de/handle/20.500.12116/22153 Using Continuations for Flexible Provision of Grid Services Giordano, Maurizio; Napoli, Claudia di Kowalczyk, Ryszard The main challenge of grid computing is to provide a unified computational infrastructure composed of networked heterogeneous resources that makes effective use of the computational power delivered by each resource. To reach this objective management of computational resources is a crucial aspect because of the decentralized, heterogeneous and autonomous nature of these resources that usually belong to different administrative domains. As such they cannot be managed by adopting a centralized approach, but more sophisticated computing methodologies are necessary. In this context, the possibility to manage the execution of services is advisable to control their provision in dynamic and changing environments. In the present work an infrastructure to model service providers is proposed to allow for flexible provision of grid services, i.e. to allow providers to dynamically adapt the execution of services according to both the changing conditions of the environment where they operate in, and the requirements of service users. The infrastructure is based on continuations, a programming paradigm that allows to control the state of code execution at programming level without directly using operating system facilities. 2007-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/22155 Towards Collaborative Service Level Agreement Negotiation He, Qiang; Yan, Jun; Yang, Yun; Kowalczyk, Ryszard; Jin, Hai Kowalczyk, Ryszard A critical issue in the Service Level Agreement management for service composition is to control the relationship between the composite service and the component services in the negotiation. However, existing approaches are inefficient. This paper presents a novel agent-based collaborative approach to address this problem. We introduce a negotiation protocol, under which the agents on the service providers’ side collaborate by exchanging information with each other to gain global knowledge of the negotiation. The collaboration can facilitate the progress of the negotiation. We also discuss the corresponding impact on the decision making strategies. 2007-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/22154 Towards Adaptive Management of QoS-aware Service Compositions - Execution Strategies Momotko, Mariusz; Gajewski, Michał; Ludwig, André; Kowalczyk, Ryszard; Kowalkiewicz, Marek; Zhang, Jian Ying Kowalczyk, Ryszard Service compositions enable users to realize their complex needs as a single request. Despite intensive research, especially in the area of business processes, web services and grids, an open and valid question is still how to manage service compositions in order to satisfy both functional and non-functional requirements as well as adapt to dynamic changes. In this paper we describe an approach towards adaptive management of QoS-aware service compositions. This approach integrates well known concepts and techniques and proposes various execution strategies based on dynamic selection and negotiation of services, contracting based on service level agreements, service enactment with flexible support for exception handling, monitoring of service level objectives, and profiling of execution data. 2007-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/22152 FIFO Queuing of Constant Length Fully Synchronous Jobs Berten, Vandy; Devillers, Raymond; Louchard, Guy Kowalczyk, Ryszard The paper examines the behaviour of a saturated multipro- cessor system to which fully synchronous parallel jobs are submitted. In order to simplify the analysis, we assume constant length jobs, a non-preemptive scheduling and a FIFO queue. We determine in particular the number of used CPUs. 2007-01-01T00:00:00Z