Research Project: Dökme Yük Terminal İşletimine Bütünleşik Yaklaşım
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Contributors
Funders
ID
TB.00153
Authors
Oğuz, Ceyda
Faculty Member
Publications
An exact algorithm for integrated planning of operations in dry bulk terminals
(Elsevier, 2019) Oğuz, Ceyda; Ünsal, Özgür; Department of Industrial Engineering; Yes; College of Engineering
We consider integrated planning problem of export dry bulk terminals. This problem consists of three important operations: (i) berth allocation, (ii) reclaimer scheduling, and (iii) stockyard allocation, and includes tidal time windows, multiple stocking pads and non-crossing of reclaimers. We exploit relationships among these operations to decompose this complex problem and propose a logic-based Benders decomposition algorithm. Master and subproblems are modeled with mixed-integer programming and constraint programming, respectively, such that complementary strengths of these programming paradigms are utilized. Computational experiments show that the proposed method can effectively solve the integrated problem for up to two weeks of planning horizon.
Reclaimer scheduling in dry bulk terminals
(Institute of Electrical and Electronics Engineers (IEEE), 2020) Ünsal, Özgür; Graduate School of Sciences and Engineering; No; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
This paper studies a complex parallel scheduling problem with non-crossing constraint, sequence dependent setup times, eligibility restrictions, and precedence relationships motivated by reclaimer scheduling in dry bulk terminals. In a stockyard of any dry bulk terminal, stockpiles are handled by reclaimers. Therefore, improving the operational efficiency of reclaimers is critical for the overall performance of these terminals which are struggling with increasing workload. We study the variants of this problem with and without stacking operations. For each variant, we present a lower and an upper bound. A strong lower bound is obtained by relaxing the non-crossing constraint and solving the resulting problem to the optimality. While this relaxation still addresses a challenging scheduling problem, proposed arc-time-indexed formulation copes with the instances of practical size. We develop a novel constraint programming formulation to provide an upper bound for the problem. Computational experiments show this robust approach is able to generate near-optimal schedules for different stockyard configurations within a minute.
Reclaimer scheduling in dry bulk terminals
(IEEE-inst Electrical Electronics Engineers inc, 2020) Ünsal, Özgür; Graduate School of Sciences and Engineering; No; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
This paper studies a complex parallel scheduling problem with non-crossing constraint, sequence dependent setup times, eligibility restrictions, and precedence relationships motivated by reclaimer scheduling in dry bulk terminals. in a stockyard of any dry bulk terminal, stockpiles are handled by reclaimers. therefore, improving the operational efficiency of reclaimers is critical for the overall performance of these terminals which are struggling with increasing workload. We study the variants of this problem with and without stacking operations. for each variant, we present a lower and an upper bound. a strong lower bound is obtained by relaxing the non-crossing constraint and solving the resulting problem to the optimality. While this relaxation still addresses a challenging scheduling problem, proposed arc-time-indexed formulation copes with the instances of practical size. We develop a novel constraint programming formulation to provide an upper bound for the problem. Computational experiments show this robust approach is able to generate near-optimal schedules for different stockyard configurations within a minute.
