9 research outputs found
Review on integrated scheduling of quay crane and yard truck
With the development of port shipping trade, the increasing container throughput has brought pressure to port operation. Research literatures on quay crane scheduling, yard truck scheduling and integrated scheduling of quay crane and yard truck are reviewed in turn. Combined with the current research, the future research direction of integrated scheduling of quay crane and yard truck is proposed
Simulation model to determine ratios between quay, yard and intra-terminal transfer equipment in an integrated container handling system
This paper presents a generic simulation model to determine the equipment mix (quay, yard and intra-terminal transfer) for a Container Terminal Logistics Operations System (CTLOS). The simulation model for the CTLOS, a typical type of discrete event dynamic system (DEDS), consists of three sub-models: ship queue, loading-unloading operations and yard-gate operations. The simulation model is empirically applied to phase 1 of the Yangshan Deep Water Port in Shanghai. This study considers different scenarios in terms of container throughput levels, equipment utilization rates, and operational bottle-necks, and presents a sensitivity analysis to evaluate and choose reasonable equipment ratio ranges under different operational conditions
Modelling and Optimizing an Open-Pit Truck Scheduling Problem
This paper addresses a special truck scheduling problem in the open-pit mine with different transport revenue consideration. A mixed integer programming model is formulated to define the problem clearly and a few valid inequalities are deduced to strengthen the model. Some properties and two upper bounds of the problem are proposed. Based on these inequalities, properties, and upper bounds, a heuristic solution approach with two improvement strategies is proposed to resolve the problem and the numerical experiment demonstrates that the proposed solution approach is effective and efficient
Adaptive autotuning mathematical approaches for integrated optimization of automated container terminal
With the development of automated container terminals (ACTs), reducing the loading and unloading time of operation and improving the working efficiency and service level have become the key point. Taking into account the actual operation mode of loading and unloading in ACTs, a mixed integer programming model is adopted in this study to minimize the loading and unloading time of ships, which can optimize the integrated scheduling of the gantry cranes (QCs), automated guided vehicles (AGVs), and automated rail-mounted gantries (ARMGs) in automated terminals. Various basic metaheuristic and improved hybrid algorithms were developed to optimize the model, proving the effectiveness of the model to obtain an optimized scheduling scheme by numerical experiments and comparing the different performances of algorithms. The results show that the hybrid GA-PSO algorithm with adaptive autotuning approaches by fuzzy control is superior to other algorithms in terms of solution time and quality, which can effectively solve the problem of integrated scheduling of automated container terminals to improve efficiency.info:eu-repo/semantics/publishedVersio
Exploring search space trees using an adapted version of Monte Carlo tree search for combinatorial optimization problems
In this article, a novel approach to solve combinatorial optimization
problems is proposed. This approach makes use of a heuristic algorithm to
explore the search space tree of a problem instance. The algorithm is based on
Monte Carlo tree search, a popular algorithm in game playing that is used to
explore game trees. By leveraging the combinatorial structure of a problem,
several enhancements to the algorithm are proposed. These enhancements aim to
efficiently explore the search space tree by pruning subtrees, using a
heuristic simulation policy, reducing the domains of variables by eliminating
dominated value assignments and using a beam width. They are demonstrated for
two specific combinatorial optimization problems: the quay crane scheduling
problem with non-crossing constraints and the 0-1 knapsack problem.
Computational results show that the algorithm achieves promising results for
both problems and eight new best solutions for a benchmark set of instances are
found for the former problem. These results indicate that the algorithm is
competitive with the state-of-the-art. Apart from this, the results also show
evidence that the algorithm is able to learn to correct the incorrect choices
made by constructive heuristics
Containerbrückeneinsatzplanung in Seehafencontainerterminals - Entwurf und experimentelle Analyse von Lösungsverfahren für das Container Sequencing Problem
Durch den Einsatz immer größerer Containerschiffe zum Transport containerisierter Güter über den Seeweg gewinnt die Produktivität der zur Be- und Entladung der Containerschiffe eingesetzten Containerbrücken in Seehafencontainerterminals immer mehr an Bedeutung. Einen erheblichen Einfluss auf die Produktivität der Containerbrücken hat die Containerbrückeneinsatzplanung. Gegenstand dieser Arbeit ist das im Rahmen der Containerbrückeneinsatzplanung auftretende Container Sequencing Problem, welches hier erstmals unter Berücksichtigung von Ladelukendeckeln und Rehandlecontainern verschiedener Containerkategorien untersucht wird. Die Problemstellung wird als ganzzahliges lineares Optimierungsmodell formuliert. Zur Lösung des Problems werden verschiedene heuristische Verfahren vorgeschlagen. Deren Leistungsfähigkeit wird anhand numerischer Experimente analysiert