| Summary: | 碩士 === 國立成功大學 === 交通管理學系碩博士班 === 91 === The time-definite freight delivery common carriers pickup, consolidate and deliver small shipments. The pure hub-and-spoke network consolidates partial loads with the result of lower operating cost. As the result, it has become the most common line-haul operations configuration for the freight delivery industry. To improve the operational efficiency, the carriers in Taiwan gradually adjusted, re-configured and transformed their line-haul operations in pure hub-and spoke networks.
The line-haul operations network planning of time-definite freight delivery common carriers includes the determination of freight paths, trailer assignment and balance, and feeder schedules to guide daily operations. Most research in the subject of operational planning limited to one daily pickup and delivery operation. Furthermore, the assumed the demand was an average of long-term historical freight demand. In practice, the demand fluctuates. In addition, multiple-frequency may potentially reduce the fleet size and overall operating cost. Thus, in this research we studied the economic effects on multiple-frequency line-haul operations under the uncertain demand. Under the uncertain demand, the multiple-stage load planning problem is to determine the freight paths and fleet size with their routes so that the sum of scheduled and expected recourse costs is minimized. The problem is a multiple-stage stochastic and integer program.
In this research, we constructed a space-time capacitated directed network for the multiple-stage line-haul operations. Subsequently, we developed a branch and bound algorithm with embedded scenario aggregation to determine the optimal operations plan. The branches were determined by scenario aggregation. For numerical experiment, we selected a set of small networks of the third largest common carrier in Taiwan. The results showed a lower operating cost than the conventionally used deterministic load plan.
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