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NSERC grants at Laurentian University Subventions du CRSNG `a l ...

NSERC grants at Laurentian University Subventions du CRSNG `a l ...

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121Nick VayenasReliability assessment of mining equipment using geneticalgorithms with probability distribution based fitnessfunctionA grant of $20,070 per year.Une subvention de 20 070 $ par année.Discovery Grant – Subvention à la découverteThis proposal is a continu<strong>at</strong>ion of an <strong>NSERC</strong> grantin the field of Genetic Algorithms (GAs) for reliabilityassessment of mining equipment. Compared to classicalreliability analysis, this research offers a novel approachwhich may lead to the formul<strong>at</strong>ion of a reliabilityassessment methodology based on GAs. Geneticalgorithms are stochastic search techniques based onthe principles of n<strong>at</strong>ural selection. The reliability ofa machine changes over time <strong>du</strong>e to its dependenceupon several factors (e.g. the oper<strong>at</strong>ing environment, number and quality ofrepairs). The use of GAs is intended to capture the impact of the factorson the reliability function of a machine by mimicking the process of heredityand n<strong>at</strong>ural selection. In GAs models, to progress from one popul<strong>at</strong>ion to thenext, members of the current popul<strong>at</strong>ion are repro<strong>du</strong>ced, crossed over andmut<strong>at</strong>ed based on the value of their current fitness using a Fitness Function(FF). So far, it has been found th<strong>at</strong> the use of the exponential probabilitydistribution as the FF in a GAs-based reliability model offers acceptablereliability estim<strong>at</strong>es. However, the st<strong>at</strong>istical properties of the exponentialdistribution conflict with the assumptions of heredity and survival of thefittest assumed by GAs. Furthermore, the maximum number of gener<strong>at</strong>ionsrequired to achieve st<strong>at</strong>istically acceptable reliability estim<strong>at</strong>es appear tovary significantly.Thus, it is now proposed to develop GAs-based models incorpor<strong>at</strong>ing othertheoretical distributions (e.g. Weibull) as FFs, as well as to investig<strong>at</strong>e thecriteria for the size of the initial popul<strong>at</strong>ion and for the maximum numberof gener<strong>at</strong>ions. The characteristics of the new models are expected to re<strong>du</strong>cethe constraints associ<strong>at</strong>ed with the st<strong>at</strong>istical assumptions imposed by the

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