Graham R. Nudd

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This paper is a tutorial introduction to the Viterbi Algorithm, this is reinforced by an example use of the Viterbi Algorithm in the area of error correction in communications channels. Some extensions to the basic algorithm are also discussed briefly. Some of the many application areas where the Viterbi Algorithm has been used are considered, including(More)
Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is emerging as one of the most important grid services. In this work, a workflow management system for grid computing, called GridFlow, is presented, including a user portal and services of both global grid workflow(More)
ion. A performance analysis system needs to encapsulate many different forms of workload description. This is in conjunction with life cycle coverage, in which many levels of abstraction occur, ranging from complexity type analysis, source code analysis, intermediate code (compile time) analysis, and actual timing information (at runtime). Hierarchical. The(More)
Workload and resource management are essential functionalities in the software infrastructure for grid computing. The management and scheduling of dynamic grid resources in a scalable way requires new technologies to implement a next generation intelligent grid environment. This work demonstrates that AI technologies can be utilised to achieve effective(More)
This paper addresses the dynamic scheduling of parallel jobs with QoS demands (soft-deadlines) in multiclusters and grids. Three metrics (over-deadline, makespan and idle-time) are combined with variable weights to evaluate the scheduling performance. These three metrics are used to measure the extent of the jobs' QoS demand compliance, the resource(More)
Performance prediction is set to play a significant role in supportive middleware that is designed to manage workload on parallel and distributed computing systems. This middleware underpins the discovery of available resources, the identification of a task’s requirements and the matchmaking, scheduling and staging that follow. This paper documents two(More)
This paper addresses workload allocation techniques for two types of sequential jobs that might be found in multicluster systems, namely, non-real-time jobs and soft real-time jobs. Two workload allocation strategies, the optimized mean response time (ORT) and the optimized mean miss rate (OMR), are developed by establishing and numerically solving two(More)
Before an application modelled as a directed acyclic graph (DAG) is executed on a heterogeneous system, a DAG mapping policy is often enacted. After mapping, the tasks (in the DAG-based application) to be executed at each computational resource are determined. The tasks are then sent to the corresponding resources, where they are orchestrated in the(More)
There is a wide range of performance models being developed for the performance evaluation of parallel and distributed systems. A performance modelling approach described in this paper is based on a layered framework of the PACE methodology. With an initial implementation system, the model described by a performance specification language, CHIP3S, can(More)
The Grid Information Service (GIS) is one of the Grid Common Services which make up the basic functions belonging to Grids. This service offers a resource discovery mechanism, of which an implementation is provided by the Monitoring and Discovery Service (MDS-2), which is part of the Globus Toolkitw. Grid applications are typically the users of this(More)