Dynamic scheduling of computationally intensive applications on unreliable infrastructures

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Computational complexity and distributed execution in water quality management

Tourist beaches on the southern coast of Turkey are surveyed in order to facilitate a standardised fuzzy approach to be used in litter prediction and to assess the aesthetic state of the coastal environment for monitoring programs. During these surveys the number of litter items on beaches were counted and recorded in different categories. The main source of litter on beaches was determined as "beach users". A fuzzy system was developed to predict the classification of the beaches, since uncertainty was generally inherent in beach work due to the high variability of beach characteristics and the sources of litter categories. This resulted in effective utilization of "the judgment and knowledge of beach users" in the evaluation of beach gradings

Distributed virtual experiments in water quality management

Since the complexity of virtual experiments (VEs) and their underlying models is constantly increasing, computational performance of monolithic software solutions is rapidly becoming insufficient. Examples of VEs are probabilistic design, model calibration, optimal experimental design and scenario analysis. In order to tackle this computational bottleneck, a framework for the distributed execution of VEs on a potentially heterogeneous pool of work nodes has been implemented. This framework was named WDVE (WEST distributed virtual experimentation) and is built on top of technologies such as C++, XML and SOAP. It was designed for stability, expandability, performance, platform-independence and ease of use. Complex VEs are most often composed of mutually independent sub-experiments, which can be run concurrently. With WDVE, a complex VE that is executed on a so-called Master machine will therefore attempt to execute its sub-experiments on Slave machines that have previously registered with the Master. The process of submitting requests for the execution of sub-experiments is transparent and involves the transfer of a description of the experiment to be executed, and the resources that are needed for the execution (i.e., model and input data). WDVE is in many ways similar to the Grid Computing paradigm, which is currently receiving widespread attention. However, WDVE is more geared towards application within the scope of water quality management

Computational Complexity and Distributed Execution in Water Quality Management

Abstract. Modeling is considered an inherent part of design, operation and optimization of Water Quality Systems. Models are used for running so-called Virtual Experiments, such as Simulation and Uncertainty Analysis. Since the complexity of VE’s is constantly increasing, there is a need for techniques that allow for timely execution of complex VE’s on real-world models. This paper touches several of these: use of efficient solvers, model coupling based on the Open Modeling Interface (OpenMI), and distributed execution. Focus however is predominantly on the software system that was developed to allow for the latter. This system has thus far been applied to the WEST modeling and simulation software package. It is a stable, efficient and platform-independent tool for transparent distributed execution of workload on work nodes within an organization. It can be regarded as conceptually similar to the Grid Computing paradigm, albeit its specific nature currently makes it more geared towards Water Quality Management systems.