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Über dieses Buch

The yard block of a container terminal is the central point of synchronisation for asynchronous container flows between deep-sea vessels and transport to the hinterland. The structure of the block stipulates that containers are stacked on top of each other with only the topmost container directly accessible by a yard crane. This book describes a holistic and integrative approach to container handling in yard blocks to optimise productivity by minimising re-handling operations. The results provide insights for academic scholars as well as for experts from practical terminal planning and operations. The approach presented is two-fold: first, a theoretical foundation of the interdependencies in decision-making is established using mathematical programming. Secondly, operations involving uncertain container arrival information are examined on the basis of a simulation with a rigorous experimental design and statistical evaluation. In this context, the book develops container-handling strategies and analyses the impact of a system for vehicle arrival management – the "Terminal Appointment System". The findings presented in this book are the result of a close cooperation with experts at the port of Hamburg and build on previous research.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction to Container Handling Research

Research in container terminal planning has received extensive attention in the past decades as a result of the importance of terminals within the global supply chain. Different research streams can be identified based on the operational area of the terminal. As an integral part of the terminal, the yard block serves the purpose of synchronising the flows between waterside and landside operations. For the purpose of a seamless synchronisation, containers in the yard block must be stacked efficiently in order to streamline container handling in general. Based on this central role of yard blocks within the terminal, open research questions about efficient container handling in yard blocks are formulated in this chapter that should be answered throughout the work. The questions are structured in three categories. First, they relate to the problem formulation and modelling of container handling in yard blocks. Second, it is asked about the underlying theoretical mechanisms governing container stacking. Lastly, questions arise about the key aspects relevant for practical container handling and how it is possible to utilise the theoretical insights for real-world yard block planning. Research goals are stated for each of the formulated research questions in order to facilitate answering them. Eventually, the outline of the work is presented in alignment with the structure of the research statement.
Filip Covic

Chapter 2. Container Terminal Environment

The three main operational areas of a container terminal, namely the waterside, yard and landside area, are briefly sketched in order to enable a basic understanding of the processes relevant for the analysis in subsequent chapters. Main planning problems, which occur in the three operational areas, are introduced and described, respectively. Coming from a general view on the entire terminal operations, a closer look is taken at the yard block level being the operational area relevant for the research statement of the work. Here, basic terminology is defined and different yard block layouts, the corresponding yard crane systems and the implications for handling operations and yard crane movement are described. Within this overview, the focus is put on automation leading to a brief statement and comparison of variants of automated stacking cranes with single and multiple cranes per block. As the work is motivated from the informational context of arrival and retrieval times of containers, the properties of time information about containers at the waterside and landside are identified and possible systems of vehicle arrival management for estimating the time information are conveyed. Following from this, the problem environment of the research study is formulated.
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Chapter 3. Container Handling in the Yard Area

All types of container handling operations in yard blocks are identified. Their properties are evaluated in order to enable a classification of handling operations. In this sense, it is distinguished between handover handling and re-handling operations. Based on the handling types, self-contained planning problems for container handling in yard blocks are formally defined. First, a general taxonomy for the problem types is purposed. Afterwards, individual problems are stated and classified according to the proposed scheme. The main properties of each problem in terms of yard block layout and yard crane system among others are evaluated and contrasted with the other handling problems for the purpose of comparison. In the end, the problem scope of this work is formulated as the result of this chapter.
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Chapter 4. Literature Review on Container Handling in the Yard Area

A wide-ranging literature review is conducted in this chapter surveying container handling problems in the time-span 1997–2018. The problems of the surveyed studies are systematically classified according to the scheme described in the previous chapter and compared based on key properties for practical yard block planning as well as for a theoretical analysis of container stacking. These include the problem scope, the planning hierarchy, time and input data properties and the modelling and solution methods among others. The results are presented in an extensive table classifying each of the 61 studies surveyed according to ten problem properties. Based on this, the main conclusions about each property are extracted and summarised in order to identify the key research streams in container handling in yard blocks. Afterwards, the literature review is aligned with other literature reviews in this field and a conclusion is given in order to provide a comprehensive overview of container handling problems. Eventually, this should support the identification of open questions in existing problems and the initialisation of new research streams in future research.
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Chapter 5. Integrated Container Handling

A complete algebraic model for yard block operations is formulated in this chapter. In this sense, it covers all defined container handling problems of the previous chapters subject to yard crane scheduling and sequencing constraints that are bounded by the capacity of a single yard crane. The aim is to assess the viability of optimising yard block operations holistically in order to examine interaction effects of block allocation, container stacking, re-handling and yard crane movement. As a result of the multitude of integrated problems, the (practical) size of a yard block and the binary decision nature of container assignment and movement, this modelling approach can be categorised within the field of large-scale integer programming. In these circumstances, this chapter serves two purposes. Firstly, it provides a formal framework for integrated container handling in the yard area where decision-dependencies can be depicted. Secondly, it helps to extract and circumscribe the core parts in terms of solvability and importance for understanding the properties of container handling. For this purpose, a core model is proposed for formalising the problem of container handling and movement aspects only which is named Container Allocation and Re-handling Problem. Afterwards, yard crane scheduling, sequencing and capacity are added to the core model as extension completing the model for yard block operations to the Container Allocation, Re-handling and Scheduling Problem. Hence, the research questions about the problem modelling are addressed within this chapter.
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Chapter 6. Algorithmic Analysis Based on the Problem Decomposability

Based on the considerations about the large-scale model structure and its solvability in the previous chapter, a solution method for the core model is developed, formally described and numerically studied. The aim is to reduce the model size in order to enable an analysis of interaction effects of container handling problems in single yard block operations. By this approach, the solution of lager instances is promoted providing an improved basis for the theoretical examination and numerical evaluation. For this purpose, a Benders decomposition approach is developed where the Master and the Sub-problem are solved as linear programs to reduce computational time. Integrality of the Master is obtained by randomised rounding based on a Fix-and-Relax procedure which enables the algorithm to escape local optima. In this process, feasibility is constructed by calling stacking rules which underlie the specific problem structure. Based on the obtained integer input to the Sub-problem from the Master, integrability of the Sub-problem is supported by a polynomial number of facet-defining valid inequalities. Within the specified runtime limit, CPLEX finds only feasible solutions for the 30% smallest test instances while the proposed algorithm generates feasibility in close to 90% of the cases including the largest ones. Moreover, the benefits of the hybrid algorithmic framework are illustrated by a numerical comparison with the original Benders decomposition and a random draw from the solution space with the help of the heuristic stacking rules. Hence, the research questions about the theoretical foundations are addressed within this chapter.
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Chapter 7. Re-marshalling Problem

Addressing the practice-orientated research questions of the work, a heuristic solution method is developed and operational tools are assessed that are apt for practical yard block operations within an online environment. As a consequence, this chapter is focused on a simulation-based approach which enables the testing of real-world cases. In this context, the Re-marshalling Problem is analysed in detail which is expected to be highly relevant to optimising container handling in yard blocks. Moreover, re-marshalling is the primary container handling type to be performed for making use of improved external truck arrival information during the dwell time of containers in the yard block. In this context, the Re-marshalling Problem is targeted within the front-end block layout embedded in full yard block operations. The combination of this environment and the underlying assumptions demonstrate a novel viewpoint on the Re-marshalling Problem which altogether has been scarcely covered in comparison to the more prominent container handling problems in the literature. Thus, the study in this chapter can be characterised as empirical study addressing practice-orientated terminal implementation and providing insights for terminal planners and operators regarding efficient yard block operations.
Filip Covic

Chapter 8. Terminal Appointment System

The Terminal Appointment System is suggested in practical terminal applications and the scientific literature as one method to cope with inadequate arrival information of external trucks. By applying a Terminal Appointment System, truck companies book a certain time slot by announcing their arrival at the terminal a predefined period beforehand. This enhancement of information can be utilised by terminals to adjust their operations and, as a consequence, streamline container handling. In this practical context, the influence of central design and operational parameters of the Terminal Appointment System on yard block operations is analysed in this chapter while employing the online heuristic approach for re-marshalling devised in the previous chapter. Hence, the focus is put on yard block productivity where the Terminal Appointment System is employed only to obtain truck arrival information without imposing any capping per time slot or inducing restrictions on the planned arrivals of trucks. Therefore, the considerations on re-marshalling of the previous chapter are integrated with the information generating aspect of the Terminal Appointment System in order to analyse the effects of different degrees of information quality and quantity on container handling. The empirical study is conducted by simulation based on a rigorous experimental design and statistical evaluation.
Filip Covic

Chapter 9. Interaction Effects of Yard Block Properties, Re-marshalling and TAS

In order to evaluate the effectiveness of re-marshalling and the Terminal Appointment System thoroughly, the impact of both is examined with a selective variation of yard block properties which are deemed to be central for the understanding of the interaction of yard block properties, re-marshalling and Terminal Appointment Systems. The aim is to eliminate any biased behaviour of the algorithm or performance enhancements through the Terminal Appointment System by certain combinations of yard block settings. For this purpose, the influences of two block parameters, are examined in this chapter. Namely, the average block occupancy influences the number of re-handling moves that can be performed in the block. Generally, it is more difficult to re-handle containers in densely filled blocks. Even in cases of a high quantity of precise arrival information, re-handling is impeded by a limited number of available empty slots. Hence, it is worthwhile to analyse how densely filled the block can be stacked while it remains possible to benefit from implementing and operating Terminal Appointment Systems. Next, it makes naturally no sense to operate the Terminal Appointment System if the considered yard block is a pure transshipment block with no external trucks arriving at its handover area. Therefore, it is important to identify the threshold for the transshipment rate of a yard block at which imprecise or unknown arrival information of trucks at the handover areas considerably impact the productivity of the yard block. The empirical study is conducted by simulation based on a rigorous experimental design and statistical evaluation.
Filip Covic

Chapter 10. Conclusions and Recommendations for Efficient Container Handling

As a conclusion, concentrated research answers are formulated in the last chapter epitomising the outcomes of pursuing the research goals set at the beginning of this work. For this purpose, the essence of each precedent chapter is summarised briefly beforehand. Based on this, the research questions are answered afterwards, providing the major conclusions of this work. Inevitably, this starts off a dilating discussion of the studied subject in future research. Hence, the final section gives an outlook on potential areas for addressing new problems in the field of quantitative planning of container handling in automated yard blocks based on time information.
Filip Covic
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