Time restrictions in forest operations planningBoštjan Kepic
, 2016, magistrsko delo
Opis: This master’s thesis deals with annual harvest operations (AHO) planning with consideration of time restrictions. We developed five models of binary integer linear programming (BILP) that schedule working groups to harvest unit areas (HUAs) according to the lowest cost possible. Total AHO costs include felling and skidding costs, transportation costs, and machine relocation costs. The first model is based on the presumption that harvesting can be planned and executed freely throughout the year. In other four, scheduling was subject to time restrictions in HUAs and differed according to the extent of time restrictions. The second model takes into account time restrictions due to unfavourable natural conditions, the third model due to disturbance-free areas of animal species, the fourth and fifth model concurrently include the impact of time restrictions due to natural conditions and disturbance-free areas. The annual workplace time in Model 2 is reduced by 14.2 %, in Model 3 by 16.9 %, in Model 4 by 29.3 % and in Model 5 by 42.3 %. The model tool used to test all the models was designed in Microsoft Excel. All five models were tested with OpenSolver 2.7.1 software. Increasing the extent of time restrictions in forest operations reduces the utilization of the annual workplace time. In testing the second model, we demonstrated that with proper organisation of an AHO plan the planner can influence the working days fallout. In the other three models, we were able to ensure the implementation of AHO plan by introducing extra working groups. Further, we confirmed that time restrictions affect the scheduling of the working groups and the sequencing of tasks. The increases in total AHO costs were explained as an increase in working groups’ costs due to lower utilization rate, an increase in depreciation costs of machines and costs due to unrealized allowable annual cut and timber sales planned for the current year. We tested each model on two examples.
Najdeno v: osebi
Ključne besede: time restrictions, binary integer programming, forestry, annual harvest operations planning, harvesting, scheduling working teams
Objavljeno: 20.09.2016; Ogledov: 4013; Prenosov: 189
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