| dc.description.abstract | A good carriage maintenance manpower supply plan helps Mass Rapid Transit (MRT) plants efficiently deal with their maintenance and improve their service quality. To design a good carriage maintenance manpower supply plan, a plant has to consider not only its operating cost, but also the uncertainty of the daily manpower demand in actual operations. However, currently the carriage maintenance in Taiwan depends on staff experience with a fixed demand in establishing the manpower supply plan, which is neither effective nor efficient. In the worst case scenario, the manpower demands for continuous time slots fluctuate drastically (e.g., on the boundaries of peak and off-peak periods), then supplying too much manpower to meet the highest demand would result in too much surplus manpower and a waste of human resources. Hence, in this research we develop for the MRT maintenance plants several deterministic-demand, stochastic-demand and mixed deterministic and stochastic demand manpower supply plan models for their long-term and short-term operations. The models are expected to be useful planning tools for the MRT maintenance plants to decide on their optimal manpower supply plans and timetables in their operations.
We employed mathematical programming techniques, incorporating the flexible manpower supply strategies, to construct several deterministic-demand scheduling models. Then, we further developed several stochastic-demand and mixed deterministic and stochastic demand manpower supply plan models by modifying the fixed demand parameters in the corresponding deterministic-demand manpower supply plan models. These models are formulated as mixed integer programs that are characterized as NP-hard. For ease of testing, we developed heuristics based on relaxing integer restriction in the deterministic-demand scheduling models. With regard to stochastic-demand and mixed demands scheduling models, we employed linear decomposition techniques, simulation techniques, coupled with CPLEX, to develop heuristics to efficiently solve the problems. To evaluate the models and the solution algorithms under stochastic demands in actual operations, we developed a simulation-based evaluation method. Finally, we performed a case study using real operating data from a Taiwan MRT maintenance plant. The preliminary results are good, showing that the models could be useful for planning carriage maintenance manpower supply. | en_US |