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Optimization of Container Handling Systems

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... This situation motivated the current work 13 that attempts to review published works in a way that reveals problems investigated, 14 simplifications, assumptions and limitations in model formation, solution approaches and 15 fruitful outcomes. 16 It must be noted that although the vast majority of scientific papers contain an 17 extensive literature review on preceding publications, their aim is not the systematic 18 classification and assessment but rather the identification of their contribution to the state of 19 the art. Similarly, in literature reviews of wide scientific areas (such as the reviews of Vis and 20 ...
... ALVs can 16 work autonomously in the quay area (by picking up or disposing a container from or to the 17 buffer area of the quay cranes) as well as in the storage yard. Nevertheless, as ALVs can 18 handle containers only at ground level, the size of the buffers imposes a limit on the number 19 of containers that may be laid down and therefore a limit to autonomous operation. In many 20 modeling approaches (especially simulation) handling equipment is represented as individual 21 entities while in others abstracted forms are use. ...
... Some 15 experienced quay crane operators occasionally implement the dual cycle mode in a small 16 portion of their work; although some container terminals have already experienced the dual 17 cycle mode technique in practice (14), port operators are reluctant for its wide implementation 18 due to its complex management and communication requirements. 19 Transfer vehicles/equipment may also perform combined inbound and outgoing 20 container transfer operations even when quay cranes operate in single cycle mode: as more 21 ...
Conference Paper
A substantial number of publish works for maritime container terminals focuses on the Quay to Storage area subsystem investigating locational, scheduling and job assignment problems for various equipment configuration, work plan formations, operating conditions and optimization objectives. The current work attempts to review published works in a way that reveals problems investigated, simplifications and assumptions in model formation, solution approaches and fruitful outcomes. Issues related to ship loading and unloading operations, assignment strategies of transfer vehicles, job assignment techniques etc are analyzed; contradictory outcomes are resolved and comments about the representativeness and applicability of the proposed models in real world problems are outlined.
... The empty travel time is not the main concern for guided vehicle scheduling problems and loads (transport requests) in a guided vehicle system should not be rejected. Meersmans (2002) proposes a heuristic based on a beam-search algorithm to dynamically schedule AGVs at a container terminal. The quality of the schedule depends on the length of the planning horizon (the scheduling problem takes into account only known jobs during that time period) and the rescheduling frequency (the frequency at which the schedule is regenerated). ...
... Sabuncuoglu and Kizilisik (2003) evaluate several online (or dynamic) scheduling policies for a FMS. They have several similar observations to Meersmans (2002): (1) the performance of the system becomes better when the frequency of rescheduling increases and (2) a better offline algorithm leads to a better online performance. Other vehicles assignment strategies have been proposed by Cordeau et al. (2002); Powell et al. (2000). ...
... Because of their simplicity, vehicle dispatching rules are easy to implement. However, as indicated by Meersmans (2002) and Sabuncuoglu and Kizilisik (2003), dynamic vehicle scheduling is often more efficient. Meersmans (2002) also indicates that dynamic vehicle scheduling has the capability of taking other factors such as co-ordination between different transportation means in facilities into account. ...
Thesis
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Thesis (Ph. D)--Erasmus Universiteit Rotterdam, 2005. TRAIL (Netherlands Research School for Transport, Infrastructure and Logistics) is a joint postgraduate Research School of the Delft University of Technology, Erasmus University Rotterdam, and the University of Groningen. Includes bibliographical references (p. [165]-173).
... Kim and Bae [14] developed a model with fixed pick up time for each container and they proposed heuristic solution for more general cases. Meersman [1] was perhaps the first researcher to consider the integrated QCs, AGV and ASC scheduling problem. He showed that this problem is NP-Hard and developed mathematical theorems for the problem of scheduling ASC-AGV-QC tasks. ...
... In the next parts we propose solutions for three terminal layouts and we use Meersman's results [1] to improve the mathematical modeling and the quality of our numerical solutions. We propose a model with two objectives: the optimization of task time for the QC-AGV-ASC problem and the minimization of the number of vehicles used. ...
... Meersman [1] used a strategy of partial order to resolve large instances of the scheduling problem: the tasks of each ASC are totally ordered. He supposes a sufficient quantity of AGVs which can ensure an optimal schedule and he concluded an important theorem. ...
... Meersmans [60] gave mathematical models for the integrated scheduling of automated handling equipment at container terminals, such as AGVs and automated stacking cranes. Exact and heuristic algorithms are presented to solve these models. ...
... It has been shown that with the heuristic solutions, close to optimal solutions can be obtained in reasonable computation times. Both the integrated approach of Meersmans [60] and Meersmans and Wagelmans [61] did not take into account that there is a limited space for AGVs waiting to be (un)loaded at the cranes. ...
... The main decision within the model concerns when and how to transport all jobs from their origins to their destinations. The output of Sinriech and Palni [84] Dynamic program 3 B i n g [ 4] Analytical models 4 Meersmans and Wagelmans [61] Branch and bound algorithm 5 Veeravalli et al. [96] Analytical models 6 Meersmans [60] Mathematical programming 7 Sinriech and Kotlarski [83] Dynamic algorithm 8 Hartmann [34] General mathematical model 9 Rashidi and Tsang [70] Minimum Cost Flow 10 Nishi et al. [64] Bilevel decomposition algorithm the model includes an assignment of orders to vehicles, a route for each vehicle and an assignment of vehicles to parking areas. Clearly, in this solution routing and scheduling aspects are combined. ...
Article
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Automated guided vehicles (AGVs) are used as a material handling device in flexible manufacturing systems. Traditionally, AGVs were mostly used at manufacturing systems, but currently other applications of AGVs are extensively developed in other areas, such as warehouses, container terminals and transportation systems. This paper discusses literature related to different methodologies to optimize AGV systems for the two significant problems of scheduling and routing at manufacturing, distribution, transshipment and transportation systems. We categorized the methodologies into mathematical methods (exact and heuristics), simulation studies, meta-heuristic techniques and artificial intelligent based approaches.
... Kim and Bae [14] developed a model with fixed pick up time for each container and they proposed heuristic solution for more general cases. Meersman [1] was perhaps the first researcher to consider the integrated QCs, AGV and ASC scheduling problem. He showed that this problem is NP-Hard and developed mathematical theorems for the problem of scheduling ASC-AGV-QC tasks. ...
... In the next parts we propose solutions for three terminal layouts and we use Meersman's results [1] to improve the mathematical modeling and the quality of our numerical solutions. We propose a model with two objectives: the optimization of task time for the QC-AGV-ASC problem and the minimization of the number of vehicles used. ...
... Meersman [1] used a strategy of partial order to resolve large instances of the scheduling problem: the tasks of each ASC are totally ordered. He supposes a sufficient quantity of AGVs which can ensure an optimal schedule and he concluded an important theorem. ...
Article
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Container terminals play a crucial role in global logistic networks. Because of the ever-increasing quantity of cargo, terminal operators need solutions for different decisional problems. In the maritime terminal, at boat arrival or departure, we observe five main problems: the allocation of berths, the allocation of query cranes, the allocation of storage space, the optimization of stacking cranes work load and the scheduling and routing of vehicles. A good cooperation between the different installations in the terminal is important in order to minimize container handling time. In an automated container terminal using Automated Guided Vehicles (AGVs) Query Cranes (QCs) and Automated Stacking Cranes (ASCs) numerical solutions have become essential to optimize operators' decisions. Many recent researches have discussed the optimization of ACT equipment scheduling using different approaches. In this paper we propose three mathematical models and an exact resolution of QC-AGV-ASC planning, the problem of tasks in an automated container terminal. Our first objective is to minimize the makespan (the time when the last task is achieved). The second objective is to minimize the number of required vehicles.
... In contrast, though the dual cycle mode is complex to coordinate, higher overall efficiency can be achieved by reducing empty travel times. Although dynamic schedule proposed by Meersmans (2002) for the automated container terminal, they considered only loading activity for the scheduling. However, in Das and Spasovic (2004), they did not differentiate the allocation process based on cycle modes as they considered loading of landside transportation. ...
... Evolutionary algorithms such as GA have been used in many studies(Bose et al., 2000, Lau and Zhao, 2008, Qingcheng and Zhongzhen, 2008 and some cases as a comparison(Briskorn et al., 2006). Heuristic approaches such as Beam Search Algorithm (BSA)(Meersmans, 2002, Kim et al., 2004, Kim and Kim, 2003, Tabu Search (TS)(Koo et al., 2004, Seo et al., 2007, Chen et al., 2007, Simulated Annealing (SA)(Kim and Moon, 2003) are also studied by logistic/transportation researchers. However, according to our understanding, a proper comparison has not been done about these techniques and that is a necessity.GA was used as the general scheduling approach in(Briskorn et al., 2006), which schedules SC, AGVs and workforce of a container terminal. ...
... However, according to our understanding, a proper comparison has not been done about these techniques and that is a necessity.GA was used as the general scheduling approach in(Briskorn et al., 2006), which schedules SC, AGVs and workforce of a container terminal. The GA based results have outperformed priority rule based heuristics with less computation time.GA was used to improve the solutions of dispatching strategies inBose et al. (2000).The results revealed that GA has the potential to improve the solution quality.Ulusoy et al., (1997) used GA to schedule machines and AGVs simultaneously in manufacturing environment.BSA was used by Meersmans(Meersmans, 2002) as a prime tool for integrated scheduling in static and dynamic environments in an automated container terminal. Further, BSA was used to minimise the total handling time of cranes and trucks of a container terminal byKim et al., (Kim et al., 2004a). ...
... As an example, we will show how our model can be implemented for the automated transportation network mentioned above. However, our approach is suitable to deal with other heavily automated transportation and transshipment systems as well, such as scheduling of container terminals, where loading and unloading operations have to be scheduled using cranes and vehicles (see Meersmans [14]), and transshipment facilities (see Kozan [12], Kozan and Preston [13], Bostel and Dejax [3]). ...
... In their models they take intermediate container storage capacity into account. Meersmans [16] considers the optimization of container handling systems, where he designs models for integrated scheduling of the handling equipment. To solve the models, he develops exact and heuristic algorithms and evaluates the performance of these algorithms. ...
Article
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Motivated by a planned automated cargo transportation network, we consider transportation problems in which the finite capacity of resources (such as vehicles, docks, parking places) has to be taken into account. For such problems, it is often even difficult to construct a good feasible solution. We present a flexible modeling methodology which allows to construct, evaluate, and improve feasible solutions. This new modeling approach is evaluated on instances stemming from a simulation model of the planned cargo transportation system.
... Because of their simplicity, vehicle dispatching rules are easy to implement. However, as indicated by Meersmans (2002) and Yang et al. (2004), dynamic vehicle scheduling is often more efficient. Meersmans (2002) also indicates that dynamic vehicle scheduling has the capability of taking other factors such as co-ordination between different transportation means in facilities into account. ...
... However, as indicated by Meersmans (2002) and Yang et al. (2004), dynamic vehicle scheduling is often more efficient. Meersmans (2002) also indicates that dynamic vehicle scheduling has the capability of taking other factors such as co-ordination between different transportation means in facilities into account. Another issue, which has to be considered in the scheduling, is vehicle parking. ...
Article
This paper presents a review on design and control of automated guided vehicle systems. We address most key related issues including guide-path design, determining vehicle requirements, vehicle scheduling, idle-vehicle positioning, battery management, vehicle routing and deadlock resolution. We discuss and classify important models and results from key publications in literature, including often-neglected areas, such as idle-vehicle positioning and battery management. In addition, we propose a new dispatching-rule classification, a framework for design and control of automated guided vehicle systems, and suggest some fruitful research directions.
... The analytical ways can give insight to relationship of system parameters in a more abstract level, Meeramans (2002), while simulation models can go more into details and can consider the interrelation between different systems in a more global way. Designing simulation models also needs special expertise, but there are some general simulation packages that can help many to escape the complexity of programming and be able to develop their simulation models easier. ...
... 16 shows that stacking cranes are more engaged with handling of containers when the selectivity is decreased. But in fact they are engaged with unproductive moves.Table 4-17 Berth productivity layout A and B table 4.17 shows that berth productivity increases by having a higher selectivity. ...
... The total system productivity is indicated by the subsystem with the lowest operating productivity. The utilization rate of the subsystem indicates the degree to which the subsystem's productivity matches the operating capacity [8,9]. ...
... The animation model is able to visualize the entities and the used transporters with their corresponding routes. The coordination system of the ARENA object model [9] window is used to place the total transportation network of the container handling system. The object model consists of a coordination system of 32720 by 32720 points, on which objects can be placed. ...
Conference Paper
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Current handling systems at deep-sea container terminals run into their physical limits and new methods of handling containers are needed to deal with the ever-growing container shipping volumes. We present a domain specific simulation model of high capacity container handling system built in collaboration with engineers and terminal operators. The engine used for the simulation model consists of model generation, resource assignment-scheduling, processing-disposal components and animation components. The component model has been built in the ARENA tool with Visual Basic extensions. Using the model we have simulated new crane concepts: the second trolley crane concepts with two trolleys separated with a buffer platform and a carrousel crane with two trolleys and one or more transporters that connect these trolleys. The results of the simulation runs show that the second trolley crane can give 12% and the carrousel crane can give 40% percent improvement in productivity of the container handling system. The simulation model can be reused for studying some other concepts of the container handling system.
... Egbelu and Tanchoco [2] put forward a variety of heuristic rules about scheduling rules in the AGV system, gave methods to evaluate these rules, and then compared the performance of a variety of different AGV scheduling methods in the following studies. Kusiak and Cyrus [3] proposed a new mathematical model, based on the original AGV scheduling model, in which the optimization objective was to shorten AGV waiting time and idle time in the scheduling system to improve system operating efficiency. Meersmans and Giuseppe et al. [4,5] used a heuristic algorithm to solve the multi-AGV scheduling problem, shorten the manufacturing cycle and task-processing time, and improve the utilization rate of AGVs. ...
... improved PSO algorithm updates the particles in two parts. The first part is the update of the first N bits of the encoding, namely the priority value; the other part is the update of the last N bits of the encoding, namely the mode value.Update the code of the first part: update speed v iN through Formula(3 ...
Article
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Abstract A modified particle swarm optimization (PSO) approach is presented for the multi‐mode resource‐constrained scheduling problem of automated guided vehicle (AGV) tasks. Various constraints in the scheduling process of the AGV system are analysed, and the types and quantities of AGVs as allocable resources are considered. The multiple‐AGV combined distribution mode and its impact on distribution tasks is also considered. Finally, a multi‐mode resource‐constrained task scheduling model is established for which the object is to minimise material delivery time. Based on the above model, the discrete particle swarm optimization algorithm that improved the basic PSO was proposed. The simulation results with the test set in PSPLIB standard library showed the effectiveness of the improved PSO algorithm.
... An efficient handling of the ships can reduce their time in port and make a seaport economically more attractive. This leads to a strong competition between seaports [1][2][3][4][5]. Extensive research has been carried out on most aspects of handling ships and containers in seaports. ...
Chapter
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In this paper we present a number of (meta-)heuristics for tackling the lock scheduling problem. The lock scheduling problem is introduced as the problem of minimising both the water usage of the lock and the waiting time of all the ships. The performance of several local search heuristics with the best improving criterion and the late acceptance criterion is examined. First parameter values for the late acceptance list length are determined.With these values all heuristics and criteria are applied to a large test set. From these experiments we conclude that the performance of the heuristics is increased by the late acceptance criterion.
... Authors found feasible scheduling solutions for the AGVs and also observed that the generation of a new service request also generates new assignment schedule for the AGVs. Meersmans [14] found solutions for scheduling problem for longer planning horizons and frequent rescheduling processes; authors developed a dynamic schedule for the material handling facility served by the AGVs and also applied a beam search heuristic algorithm for the dynamic scheduling of AGVs. The dynamic schedule found to be dependent on the length of planning horizon, and after completion of the planning horizon, the rescheduling was performed. ...
Article
The automated guided vehicles (AGVs) are extensively applied for material handling operations in the flexible manufacturing system (FMS) facilities. The scheduling decisions for the multi-load AGVs serving in the FMS with minimum travel time, waiting time and time to serve jobs are highly significant from the sustainable profits point of view. The present study proposes a combination of particle swarm optimization (PSO) for global search and memetic algorithm (MA) for local search termed as the modified memetic particle swarm optimization algorithm (MMPSO) for scheduling of multi-load AGVs in FMS. The newly proposed algorithm is applied for the generation of initial feasible solutions for scheduling of multi-load AGVs with minimum travel and minimum waiting time in the FMS. From the computational experiments, it is observed that the proposed MMPSO algorithm performs an effective and efficient exploration and exploitation process and further yields promising results for the multi-load AGVs scheduling problem in the FMS facility.
... Based on the 0-1 planning idea, the RGV dynamic scheduling model under a process processing demand is obtained. Construct a heuristic algorithm [15] and solve the model through simulation. The dynamic programming model is one of the optimization methods in solving the dynamic scheduling problem [16,17]. ...
... The study also indicates 'that it is more important to base a planning on a long horizon with inaccurate data, than to update the planning often in order to take newly available information into account'. These results are also included in the PhD-thesis of Meersmans[131]. Carrascosa et al.[23]present a multi-agent system architecture to solve the automatic allocation problem in container terminals in order to minimize the ships' docking time. The paper focuses on the management of gantry cranes by a 'transtainer agent'. ...
Article
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In the last four decades the container as an essential part of a unit-load-concept has achieved undoubted importance in international sea freight transportation. With ever increasing containerization the number of seaport container terminals and competition among them have become quite remarkable. Operations are nowadays unthinkable without effective and efficient use of information technology as well as appropriate optimization (operations research) methods. In this paper we describe and classify the main logistics processes and operations in container terminals and present a survey of methods for their optimization.
... Some research has been conducted on the integrated scheduling of different container handling systems to make strategic or tactical decisions for the terminal operations. Meersmans (2002) provides models and algorithms for scheduling equipment in an integrated way in an automated container terminal. However, only loading operations for outbound containers are considered. ...
Article
This paper studies the interactions between crane handling and truck transportation in a maritime container terminal by addressing them simultaneously. Yard trucks are shared among different ships, which helps to reduce empty truck trips in the terminal area. The problem is formulated as a constraint programming model and a three-stage algorithm is developed. At the first stage, crane schedules are generated by a heuristic method. At the second stage, the multiple-truck routing problem is solved based on the precedence relations of the transportation tasks derived from the first stage. At the last stage a complete solution is constructed by using a disjunctive graph. The three procedures are linked by an iterative structure, which facilitates the search for a good solution. The computational results indicate that the three-stage algorithm is effective for finding high-quality solutions and can efficiently solve large problems.
... Dispatching rules are generally rather easy to implement and especially helpful in highly dynamic and stochastic environments where schedules would have to be updated frequently. However, Meersmans [Mee02] and Yang et al. [YJM04] show that dynamic scheduling is able to outperform dispatching rules, but is only applicable for rather small instances. In order to make a dispatching decision (based on path information), path planning is required. ...
Article
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In autonomously organized block stacking warehouses, Automated Guided Vehicles (AGVs) control material handling without requiring any technical integration or Warehouse Management System (WMS). In this paper, we present related decision problems and provide a short literature overview for each one. We found that many existing approaches do not exploit the full potential of available flexibility. By focusing on operational decisions, we introduce the Autonomous Block Stacking Warehouse Problem (ABSWP) and discuss major challenges which must be tackled by future solution approaches.
... Vis (2004) observes that most of the literature on scheduling hardly considers constraints imposed by limited capacities of transition equipment, parking places, critical tracks, etc.. For instance, the integrated mathematical model presented by Meermans (2002) on terminal logistics neglect limited capacities on transition platforms. An exception is the study Ebben et al. (2004b) presenting an approach where limited capacities are taken into account put into a multi-period, rolling finite horizon programming model. ...
Article
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This study concerns the deployment of large numbers of container transporting vehicles on a network consisting of (dedicated) roads and logistic sites such as container terminals. Each site is managed autonomously by a site manager. The fleet of vehicles is deployed by a fleet manager. On request of the site managers, the fleet manager allocates vehicles to be hired by the site managers. Next, within these allocations, each site manager issues transportation jobs and assigns these jobs to the allocated vehicles. The objective of the fleet manager is to avoid unpaid empty driving and to keep the size of its fleet just large enough the serve the demand for vehicles. The objective of the site managers is to minimize the operational costs. In this context a new coordination system is proposed to allocate vehicle capacity, operating on the basis of a win-win situation for all actors. The coordination takes place at two levels. One level concerns the drawing up of an adaptive fleet deployment plan. The other level resides under control of the individual site managers and concerns the assignment of transportation jobs to vehicles, given the allocations of the fleet deployment plan. Both use repetitive linear programming procedures. Small size simulation experiments show that the approach might be effective.
... Authors found that time window constraint every time generate a new service request along with new assignment schedule for AGVs. Beam search algorithm for dynamic scheduling of AGVs serving in FMS was proposed by Meersmans (2002). It was found that scheduling depends on the length of the planning horizon and after completion of the planning horizon, rescheduling is carried out. ...
... Very little of the existing literature focuses on the integrated scheduling problem of various types of handling equipment used at container terminals. Meersmans (2002) provides models and algorithms for scheduling the equipment in an integrated way in an automated container terminal. However, only loading operations are considered. ...
Article
The scheduling problem in a container terminal is characterized by the coordination of different types of equipment. In this paper, we present an integrated model to schedule the equipment. The objective is to minimize the makespan, or the time it takes to serve a given set of ships. The problem is formulated as a Hybrid Flow Shop Scheduling problem with precedence and Blocking constraints (HFSS-B). A tabu search algorithm is proposed to solve this problem. Certain mechanisms are developed and introduced into the algorithm to assure its quality and efficiency. The performance of the tabu search algorithm is analyzed from the computational point of view.
... It was observed that a time window constraint with generation of new service request also generates a new assignment schedule for AGVs in operation. Meersmans (2002) developed the dynamic schedule for AGVs serving in material handling facility by applying a beam search algorithm heuristic. The scheduling was dependent on the length of planning horizon and after completion of the planning horizon a rescheduling was carried out. ...
... Meersmans [16] considers the optimization of container handling systems, where he designs models for integrated scheduling of the handling equipment. To solve the models, he develops exact and heuristic algorithms and evaluates the performance of these algorithms. ...
Article
One of the major planning issues in large scale automated transportation systems is so-called empty vehicle management, the timely supply of vehicles to terminals in order to reduce cargo waiting times. Motivated by a Dutch pilot project on an underground cargo transportation system using Automated Guided Vehicles (AGVs), we developed several rules and algorithms for empty vehicle management, varying from trivial First-Come, First-Served (FCFS) via look-ahead rules to integral planning. For our application, we focus on attaining customer service levels in the presence of varying order priorities, taking into account resource capacities and the relation to other planning decisions, such as terminal management. We show how the various rules are embedded in a framework for logistics control of automated transportation networks. Using simulation, the planning options are evaluated on their performance in terms of customer service levels, AGV requirements and empty travel distances. Based on our experiments, we conclude that look-ahead rules have significant advantages above FCFS. A more advanced so-called serial scheduling method outperforms the look-ahead rules if the peak demand quickly moves amongst routes in the system.
... Bose et al.(2000) dealt with dispatching strategies for straddle carriers. Meersmans (2002) provided models and algorithms for scheduling container handling equipment in an integrated way in an automated container terminal but considered only loading operations. ...
Article
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An integrated model is presented to schedule the container handling system. The objective is to improve the cooperation between different types of equipments, and to increase the productivity of the terminal. The problem is formulated as a Hybrid Flow Shop Scheduling problem with precedence constraint, setup times and blocking (HFSS-B). A tabu search algorithm is proposed to solve this problem. The quality and efficiency of the proposed algorithm is analyzed from the computational point of view.
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This paper develops a joint approach to solve the problem of integrated scheduling of different types of material handling equipment in a typical automated air cargo handling system. Due to the nature of the operations, the schedules for different cooperating equipment are highly interactive. In order to formally describe the interactive properties of cooperating equipment, an event framework for the specification of an automated cargo handling system and a model for the integrated scheduling for more than one type of cooperating equipment is developed. A heuristic algorithm, known as the extended maximum-matching algorithm (EMMA), is proposed to solve the joint scheduling problem. The performance of the proposed EMMA is evaluated via extensive numerical studies. Experimental results show that the EMMA can be readily adapted to real-world applications.
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Thesis (doctoral)--Erasmus Universiteit Rotterdam, 2004.
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In automated maritime terminals at import, containers location problem and QC-AGV-ASC planning are generally treated separately. This approach is not efficient because container location has a direct impact on the QC-AGVASC planning optimality. In this paper, we resolve the planning of QC-AGV-ASC tasks and the containers location problem in automated maritime terminals at import in one time. We propose a new bi-objective model determining the minimal storage time with the optimal storage space organization. We minimize the makespan “date of last task” and the storage space organization with a priority of minimizing the storage time. We organize the storage space by minimizing the risk of unproductive moves caused by containers location decision. We propose a hybrid genetic and a tabu search approaches to solve efficiently the problem.
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For the efficient operation of automated container terminals, it is essential to synchronize all the operations of quay cranes, automated guided vehicles, and automated yard cranes. This study addresses a look-ahead scheduling of ship operations for synchronizing all the operations using different handling equipment. We have analyzed various precedence relationships among the different equipment operations. The precedence relationships are represented in graphical forms that were used to find the critical handling tasks, whose schedules must be changed to improve the productivity of ship operations. An improvement algorithm for the constructed schedule is suggested based on a simple neighborhood search. This scheduling method was evaluated using a simulation study.
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In this paper we consider a job shop scheduling problem with blocking (BJSS) constraints. Blocking constraints model the absence of buffers (zero buffer), whereas in the traditional job shop scheduling model buffers have infinite capacity. There are two known variants of this problem, namely the blocking job shop scheduling with swap allowed (BWS) and the one with no swap allowed (BNS). This scheduling problem is receiving an increasing interest in the recent literature, and we propose an Iterated Greedy (IG) algorithm to solve both variants of the problem. IG is a metaheuristic based on the repetition of a destruction phase, which removes part of the solution, and a construction phase, in which a new solution is obtained by applying an underlying greedy algorithm starting from the partial solution. A comparison with recent published results shows that the iterated greedy algorithm outperforms other state-of-the-art algorithms on benchmark instances. Moreover it is conceptually easy to implement and has a broad applicability to other constrained scheduling problems.
Chapter
At automated container terminals, containers are transshipped from one mode of transportation to another. Automated vehicles transport containers from the stack to the ship and vice versa. Two different types of automated vehicles are studied in this paper, namely automated lifting vehicles and automated guided vehicles. An automated lifting vehicle is capable of lifting a container from the ground by itself. An automated guided vehicles needs a crane to receive and deliver a container. In designing automated container terminals one have to consider the choice for a certain type of equipment. The choice for a certain type of equipment should be made by performing a feasibility and economic analysis on various types of equipment. In this paper, we examine effects of using automated guided vehicles and automated lifting vehicles on unloading times of a ship, with simulation studies. In choosing a certain type of equipment we have considered criteria such as unloading times of a ship, occupancy degrees and the number of vehicles required. 38% more AGVs need to be used than ALVs. From this specific study, we conclude that, by observing only purchasing costs of equipment, ALVs are a cheaper option than AGVs. To obtain an accurate analysis we have performed a sensitivity analysis. It can be concluded that the design of the terminal and technical aspects of quay cranes impact the number of vehicles required and as a result the choice for a certain type of equipment.
Thesis
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AIn our study, we consider two optimization problems in automated container terminals at import; the first is the vehicle scheduling problem; and the second is the integrated problem of location assignment and vehicle scheduling. In the first part of our study, we propose different traffic layout adapted to the two studied problems and to every kind of automated container terminal. We also introduce relevant reviews of literature treating the optimization of container handling systems at maritime terminal, the optimization of general automated guided vehicle system and the multi-objective optimization in general, and in particular context of maritime container terminals. In the second part, we resolve the planning of QC-AV-ASC (Quay Cranes-Automated Vehicles - Automated Stacking Cranes). We present an effective model for every kind of traffic layout. Moreover, we propose an efficient bi-objective model which is important to determine the optimal storage time and the minimal number of required AVs. CPLEX resolutions are used to prove the efficiency of our modelling approach. In the third part of this thesis, we explore a problem which has not been sufficiently studied: the integrated problem of location assignment and vehicle scheduling (IPLAVS), in Maritime Automated Container Terminal (MACT) at import. This part represents a new and realistic approach of MACT optimization considering mono-objective and multi-objective aspect.
Chapter
The operational performance of automated RMGC systems is to a large extent determined by the planning strategies applied for container stacking, crane scheduling and crane routing. In the present chapter, these operational planning problems are addressed in depth. It is started with the container-stacking problem. After reviewing and classifying existing stacking strategies, a new stacking approach is presented, which allows for a weighted combination of different stacking strategies, and a procedure for generating and scheduling housekeeping moves is introduced. Thereafter, the crane-scheduling problem is addressed. After this problem is discussed and an overview on known solution approaches is given, some new scheduling strategies are presented which are based on priority rules, integer programming, enumeration and genetic algorithms. Finally, the problem of routing RMGCs is introduced, relevant literature for that problem is discussed and different claiming-based routing strategies are presented.
Chapter
As the actual decoupling point between maritime and inland transport, seaport container terminals play an essential role in the international container transport network, which is at the same time one of the greatest drivers and one of the greatest profiteers of the globalisation. In this chapter, the basic terms, facts and problems of seaport container terminals are introduced in order to prepare the ground for all following analyses. After a brief introduction of the container logistics sector as a whole, functions, operations and equipment types of container terminals are described, which is followed by definitions of several design and performance indicators for container terminals. Finally, a comprehensive overview on all kinds of planning problems arising at seaport container terminals is provided.
Chapter
This chapter provides an introduction to maritime terminal configuration and operational problems. The structure of typical container terminals and associated decision problems is discussed. A case study of one of the largest container terminals, PSA Singapore Terminals, is given. A literature review on selected key problems in container terminals such as berth allocation, quay crane scheduling, transportation, yard crane scheduling, and the integration of decision problems is conducted.
Chapter
In diesem Kapitel werden Container-Terminals (CT) vorgestellt, die den Untersuchungsgegenstand dieser Arbeit bilden. Es erfolgt zunächst eine Darstellung grundlegender Strukturen eines Terminals, zusammen mit einer detaillierten Prozessbeschreibung und Definition der relevanten Begrifflichkeiten. Dieser Beschreibung folgt eine umfassende Darstellung bestehender Modelle und Methoden zur Planung von Entscheidungsproblemen in Container-Terminals.
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In this thesis, the performance at the labor market of full-time university educated auditors and part-time Nivra educated auditors have been compared. The primary goal of this thesis is to get some insight into the labor market prospects of (future) graduates of the newly set up dual tracks in higher education. Dual tracks are set up next to the already existing full-time educational tracks. Since most dual educational tracks in higher education have no or hardly any graduates yet it is not possible to compare the labor market prospects of dual and full-time graduates. Therefore, we have looked for a profession with the two educational tracks already existing for quite some time and with both educational tracks having a large number of graduates. One occupational group which meets these conditions is the group of auditors. The two groups of auditors have been compared on topics like job performance, wages, tenure, job mobility and sector choice. Dual educational tracks have been promoted in higher education because it is believed, based on experiences in intermediate vocational education, that the combination of learning and studying facilitates the transition from school to work. However, it is shown in this thesis that the long term prospects between graduates from full-time and dual education of a particular study may differ. Empirical analysis has shown that wages of Nivra educated auditors who are on the payroll are relatively low compared to the wages of full-time educated auditors. Furthermore, job mobility among Nivra educated auditors is relatively low and Nivra educated auditors work relatively often in auditing jobs whereas the full-time educated auditors work relatively often in non auditing jobs. These differences are likely to be due to differences in the composition of the human capital of these differently educated auditors. Some of the differences in labor market prospects have also been found for graduates of dual and full-time education in intermediate vocational education. This indicates that our findings do not only hold for the education in auditing but may be generalizable to other studies in higher education as well. For auditors it is not that serious that Nivra educated auditors are relatively immobile and work relatively often in the occupational field directly related to their education, since employment among auditors is high and rather stable. But other educational fields prepare people for occupations in which employment may be more vulnerable to conjunctural variation. It may be very hard for graduates from dual educational tracks to find work when an economic downturn hits their occupational field. The graduates from the full-time education may be better off then because it is easier for them to find work outside the occupational field corresponding with their education.
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We investigate the family of facet defining inequalities for the asymmetric traveling salesman (ATS) polytope obtainable by lifting the cycle inequalities. We establish several properties of this family that earmark it as arguably the most important among the asymmetric inequalities for the ATS polytope known to date. In particular, we give several results that characterize the pattern of lifting coefficients and thereby facilitate the identification of facet defining inequalities. This characterization is used to investigate three new, large classes of lifted cycle inequalities that we call shell, fork and curtain inequalities. These latter inequalities have unbounded Chvatal rank. Furthermore, the pattern of lifting coefficients that we identify makes it easy to develop efficient separation routines. Finally, each member of the family is shown to have a counterpart for the symmetric TS (STS) polytope that is often new, and is obtainable by mapping the inequality for the ATS polytope into a certain face of the STS polytope and then lifting the resulting inequality into one for the STS polytope itself.
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This paper deals with a stowage plan for containers in a container ship. Containers on board a container ship are placed in vertical stacks, located in many bays. Since the access to the containers is only from the top of the stack, a common situation is that containers designated for port J must be unloaded and reloaded at port I (before J) in order to access containers below them, designated for port I. This operation is called "shifting". A container ship calling at many ports may encounter a large number of shifting operations, some of which can be avoided by efficient stowage planning. In general, the stowage plan must also take into account stability and strength requirements, as well as several other constraints on the placement of containers. In this paper, we only deal with stowage planning in order to minimize the number of shiftings, without considering stability and several other constraints. First, we briefly present a 0-1 binary linear programming formulation that can find the optimal solution for stowage planning. However, finding the optimal solution using this model is quite limited because of the large number of binary variables and constraints needed for the formulation. Moreover, in [3] the stowage planning problem is shown to be NP-complete. For these reasons, the Suspensory Heuristic Procedure was developed.
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Integer and combinatorial optimization deals with problems of maximizing or minimizing a function of many variables subject to (a) inequality and equality constraints and (b) integrality restrictions on some or all of the variables. Because of the robustness of the general model, a remarkably rich variety of problems can be represented by discrete optimization models. This chapter is concerned with the formulation of integer optimization problems, which means how to translate a verbal description of a problem into a mathematical statement of the form linear mixed-integer programming problem ( MIP), linear (pure) integer programming problem ( IP), or combinatorial optimization problem (CP). The chapter presents two important uses of binary variables in the modeling of optimization problems. The first concerns the representation of nonlinear objective functions of the form l>jfj(yj) using linear functions and binary variables. The second concerns the modeling of disjunctive constraints.
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This study is based on a major container terminal operator in Hong Kong. Container terminals form a link in the transport chain for transhipment and temporary storage of containers. The service time for vessels including waiting time for berthing must be minimal in order to reduce costs for shipping lines. The use of heuristics and computer simulation to measure different allocation strategies is demonstrated. The existing performance measures of allocation are evaluated and prioritized. Three sets of allocation policies are developed to tackle the day-to-day allocation problems with a view to increasing operational efficiency and enhancing customer service levels. Results show that all three proposed allocation policies have substantial improvements over the existing policy.
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In this paper, a methodology for generating automated solutions to the container stowage problem is shown. The methodology was derived by applying principles of combinatorial optimization and, in particular, the Tabu Search metaheuristic. The methodology progressively refines the placement of containers, using the Tabu search concept of neighbourhoods, within the cargo-space of a container ship until each container is specifically allocated to a stowage location. Heuristic rules are built into objective functions for each stage that enable the combinatorial tree to be explored in an intelligent way, resulting in good, if not optimal, solutions for the problem in a reasonable processing time.
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We consider the linear programming formulation of the asymmetric travelling salesman problem. Several new inequalities are stated which yield asharper characterization in terms of linear inequalities of the travelling salesman polytope, i.e. the convex hull of tours. In fact some of the new inequalities as well as some of the well-known subtour elimination constraints are indeedfacets of the travelling salesman polytope, i.e. belong to the class of inequalities that uniquely characterize the convex hull of tours to an-city problem.
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Iris Vis was born in 1974 in Leidschendam. May 2002 - Assistant professor at the School of Economics and Business Administration, Vrije Universiteit Amsterdam 1999, Visiting scholar at Georgia Institute of Technology, School of Industrial and Systems Engineering, october - december September 1997 - May 2002, Ph.D. candidate at the Rotterdam School of Management/Faculteit Bedrijfskunde, Erasmus University Rotterdam Research Areas logistics, material handling systems, cross-docking centres, number of vehicles, scheduling, storage and retrieval, container terminals
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Optimising the container transfer schedule at the multimodal terminals is known to be NP-hard, which implies that the best solution becomes computationally infeasible as problem sizes increase. Genetic Algorithm (GA) techniques are used to reduce container handling/transfer times and ships' time at the port by speeding up handling operations. The GA is chosen due to the relatively good results that have been reported even with the simplest GA implementations to obtain near-optimal solutions in reasonable time. Also discussed, is the application of the model to assess the consequences of increased scheduled throughput time as well as different strategies such as the alternative plant layouts, storage policies and number of yard machines. A real data set used for the solution and subsequent sensitivity analysis is applied to the alternative plant layouts, storage policies and number of yard machines.
Article
Besides loading and discharging of ships, trucks and railway internal transportations are performed at a container terminal. Those transports amount to about 100000 km a year at the Container Terminal of the Hamburger Hafen- und Lagerhaus AG. Different methods for the routing of the vehicles (Straddle Carriers) were tested to minimize no-load ways. Heuristics solving theMultiple Travelling Salesman Problem were applied to the routing problem as well as a method forsequencing insertions in printed circuit board assemblies andrules for machine scheduling. Simulation with real data indicated a total saving of 20–35% in no-load distances which correspond to about 20000 km a year. The routing solution was implemented into a radio data transmission system. Neben dem Be- und Entladen von Schiffen, LKWs und Bahnwaggons werden interne Transporte an einem Containerterminal durchgeführt, die sich bei der Hamburger Hafen- und Lagerhaus AG auf ca. 100000 km im Jahr summieren. Um die Leerwege zu minimieren, wurden verschiedene Methoden zur Lösung des Touren-Problems getestet. Dies waren sowohl Heuristiken zur Lösung desMultiplen Travelling Salesman Problems, wie zur Reihenfolgenbildung bei derBestückung von Platinen mit elektronischen Bauteilen undVerfahren der Maschinenbelegung. Simulationen mit Echtdaten ergaben, daß die Leerwege um 20–35% reduziert werden können, was einer jährlichen Einsparung von ca. 20000 km entspricht. Das Optimierungsverfahren wurde in eine Datenfunkanwendung zur Steuerung der Fahrzeuge integriert.
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This paper presents a new algorithm for the flexible manufacturing system (FMS) scheduling problem. The proposed algorithm is a heuristic based on filtered beam search. It considers finite buffer capacity, routing and sequence flexibilities and generates machine and automated guided vehicle (AGV) schedules for a given scheduling period. A new deadlock resolution mechanism is also developed as an integral part of the proposed algorithm. The performance of the algorithm is compared with several machine and AGV dispatching rules using mean flow time, mean tardiness and makespan criteria. It is also used to examine the effects of scheduling factors (i.e., machine and AGV load levels, routing and sequence flexibilities, etc.) on the system performance. The results indicate that the proposed scheduling algorithm yields considerable improvements in system performance over dispatching rules under a wide variety of experimental conditions.
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In this paper, we describe a simulation program that models the transfer of containerized cargo to and from ships. Container port operations are extremely important from an economic standpoint, making them a prime target for productivity improvements. They are also inherently very complex since they are at the center of two or more modes of transportation, involve the interaction of several organizations and support groups, and rely on a variety of stochastic processes. The simulation program allows the operator to specify a wide variety of parameters and the manner in which the simulation is to be executed. The major focus of the paper is on the impact of work crew schedules on container port productivity.
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A methodology is proposed to determine the storage location of an arriving export container considering its weight. We consider the configuration of the container stack and the weight distribution of containers in the yard-bay. A dynamic programming model is formulated to determine the storage location to minimize the number of relocation movements expected for the loading operation. We also develop a decision tree from the set of the optimal solutions to support real time decisions. The performance of the decision tree is evaluated by the number of decisions that are different from the optimal solutions of the slower dynamic programming solution method.
Article
Typical cargo ships spend 60% of their time in port, costing their owners about $1000 per hour. In this paper, we attack such costs with a method to speed loading and unloading. We model the need for container handling as generic “work,” which cranes can do at a constant rate. Each hold of each ship has a given amount of this work and cranes can interrupt their work on individual holds without any loss of efficiency. In the parlance of scheduling theory, this constitutes an “open shop” with parallel, identical machines, where jobs consist of independent, single-stage, preemptable tasks. Practical problems often involve only a few ships but many holds; the complication of preemptable tasks makes them very complex. The paper presents a branch and bound method which, for this model, minimizes delay costs (weighted tardiness). As part of the method, we extend previous solutions to the feasibility problem of preemptive machine scheduling (to cases where multiple machines can work simultaneously on a single task). Computational results and extensions to more complicated problems are offered. Certain concepts developed here may also be applicable to other problems, both in scheduling and elsewhere. In particular, they may lead to optimal solutions of problems for which feasibility determination methods already exist.
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In recent years, liner shipping has experienced an explosion in containership size. This is explained by the economies of scale in utilising such ships. This paper presents a model which quantifies the economies of scale in operating large containerships. A sensitivity analysis is conducted to test the effect of various input scenarios and the results analysed to determine optimal containership size with respect to different operational scenarios. Inferences are then drawn concerning the optimal deployment of the existing fleet of large containerships, likely future trends in containership size and deployment and the impact these trends will have upon container operations, logistical systems and ports.
Article
This paper models the seaport system with the objective of determining the optimal storage strategy for various container-handling schedules. A container location model (CLM) is developed, with an objective function designed to minimise the turn around time of container ships, and solved using genetic algorithm (GA). The results section presents an analyses of different resource levels and a comparison with current practice at the Port of Brisbane.Scope and purposeBerthing time of a container carrying ship accounts for a considerable proportion of its journey. Shipping lines are mainly concerned with the waiting time and berthing time of the ships at the port. This paper models the storage location of containers at a seaport with the view to minimising the transfer time to the ship. A genetic algorithm is used to find a solution to the model. Changes to the seaport infrastructure is considered and compared to the benchmark. This model can be used as an operation or planning tool to assess future developments.
Article
A queuing network model of the logistic activities related to the arrival, berthing, and departure processes of vessels at a container terminal is presented in this paper. Non-standard service stations, time-dependent priority mechanisms, and complex resource allocation policies prevent the use of analytical approaches to the solution. By adopting the process approach, a simulation model for the above queuing network has been developed. This requires a limited effort when using graphical objects of the Visual SLAM language for discrete-event simulation. Good validation results, against response measures on a real system, are obtained using aggregated data related to a finite time horizon. Steady-state simulation results illustrate the use of the model for a “what if” optimisation approach to the berth planning problem.
Article
This paper proposes a simulation model for container terminal system analysis. We assume that the container terminal consists of gate, container yard, and berth. The facilities used in the container terminal are transfer cranes, gantry cranes, trailers, and yard tractors. The simulation model is developed using an object-oriented approach, and using SIMPLE++, object-oriented simulation software. We also consider a simple container terminal which is a reduced system of a real terminal in Pusan, Korea and we will analyze the performance of the system.