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Yayın Evaluation of alternative maintenance strategies on a complex system in thermal power systems(Işık Üniversitesi, 2020-08-12) Türkali, Busenur; Özgür Ünlüakın, Demet; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Endüstri Mühendisliği - Yöneylem Araştırması Yüksek Lisans ProgramıIn recent years, due to the continuous development of the industry and the rapid increase in the system complexity, maintenance policies have become more important. Unplanned downtimes due to unexpected failures may lead to huge problems in almost all industry branch. However, carrying out maintenance more than the required to prevent unexpected failures increases maintenance cost signicantly. Thus, balancing the number of reactive and proactive maintenance is very important. The aim of this thesis is to develop maintenance methods under the reactive, condition-based and proactive maintenance strategies using dynamic Bayesian networks (DBNs) in thermal power plants. DBNs which are are probabilistic graphical models, are selected to model the system because they are very effective to formulate the stochastic and structural dependencies between the components. In this study, we evaluate alternative maintenance strategies on a complex systembased on two factors: total number of maintenance and total maintenance cost in a given planning horizon. The proposed maintenance methods are simulated on a multi-component thermal power plant system which has a very complex structure with hidden components among which there are stochastic and structural dependencies. Scenarios are designed considering the maintenance dependability of parallel systems during proactive activities and different reactive cost structures. As a result, performances of all proposed maintenance strategies and methods are compared and analysed under each scenario and the most promising ones are highlighted.Yayın Designing project management systems(IEEE, 2011) Karayaz, Gamze; Keating, Charles B.; Henrie, Morgan E.The purpose of this paper is to develop the concept of project management system from the perspective of systems science. There is a need to extend the body of knowledge for project management. In particular, the application of systems perspectives and systems theory offers a significant opportunity to advance the current state of project management knowledge. Although there have been suggestions of systems approaches for project management, rigorous systems science has not been used to support these depictions. First, we develop the background and define a perspective of project management systems. Second, assumptions and principles are drawn from systems science to provide a foundation for project management systems. Third, a model for project management systems is developed from systems sciences and management cybernetics. Our initial explorations are promising, demonstrated by a case study application review using a complex system of systems (SoS) project encompassed multiple government agencies, and we offer future directions and implications for further model refinements, applications, and research into project management systems.
