Türk Hava Kuvvetleri'nde fabrika seviyesi koruyucu bakım

In this thesis, we study the Factory Level Preventive Maintenance Problem(FLPM) experienced by Turkish Air Force (TUAF). This problem is a specificcase of Nonpreemptive Resource Constrained Multiple Project Scheduling withMode Selection (NRCMPSMS); allocation of limited resources to competingactivities of multiple project of different types in which the duration of an activityis determined by the mode selection and the activity flow is dependent on thetype of the project. The objective is to determine the start (finish) time andthe mode of each project?s each activity so that the minimal total weightedtardiness and total incurred cost are obtained. We proposed a heuristic for thisproblem definition which is composed of two phases and apply it to a real lifeproblem experienced by TUAF. In the first phase, the aim is to construct aninitial schedule with minimum total weighted tardiness and in the second phase,this schedule is improved in terms of total incurred cost by the mode selectionexchanges. Since the activity due date information is not available but requiredin prioritization of the activities, we develop five FLPM specific activity due dateestimation methods. We run the proposed heuristic for three different weightiiifigures which are determined by the Analytic Hierarchy Process and the onebeing used by TUAF. In addition, we study the influence of the release and thedue dates of the aircrafts on the objective functions. We propose a determinationmethod for each of the release and the due dates that aims finding the tightnesslevels of these two parameters. The release date determination method thatwe propose relates the arrival rate of the aircrafts with the utilization of thebottleneck resource whereas the due date determination method that we proposerelates the due dates of the aircrafts with the fraction of the number of tardyjobs in percentages. We investigate the performance of the activity due dateestimation methods in terms of the objective functions and the computationaleffort required by the tightness levels of the release and the due date that arefound by the determination methods that we propose.Keywords: Resource constrained project scheduling, multiple projects, modeselection, project types, weighted tardiness.iv