Strategic allocation of cyclically calling vessels for multi-terminal container operators

We consider a terminal operator who provides container handling services at multiple terminals within the same port. In this setting, the well-known berth allocation problem can no longer be considered for each terminal in isolation since vessel calls should be spread over the various terminals to avoid peaks and troughs in quay crane utilization, and an allocation of two connecting vessels to different terminals will generate inter-terminal container transport. In this paper, we address the problem of spreading a set of cyclically calling vessels over the various terminals and allocating a berthing and departure time to each of them. The objectives are (1) to balance the quay crane workload over the terminals and over time and (2) to minimize the amount of inter-terminal container transport. We develop a solution approach based on mixed-integer programming that allows to solve real-life instances of the problem within satisfactory time. Additionally, a practical case study is presented based on data from the terminal operator PSA Antwerp who operates multiple terminals in the port of Antwerp, Belgium. The computational results show the cost of the currently agreed schedules, and that relatively small modifications can significantly reduce the required crane capacities and inter-terminal transport.     

A cooperative quay crane-based stochastic model to estimate vessel handling time

Having a good estimate of a vessel’s handling time is essential for planning and scheduling container terminal resources, such as berth positions, quay cranes (QCs) and transport vehicles. However, estimating the expected vessel handling time is not straightforward, because it depends on vessel characteristics, resource allocation decisions, and uncertainties in terminal processes. To estimate the expected vessel handling time, we propose a two-level stochastic model. The higher level model consists of a continuous-time Markov chain (CTMC) that captures the effect of QC assignment and scheduling on vessel handling time. The lower level model is a multi-class closed queuing network that models the dynamic interactions among the terminal resources and provides an estimate of the transition rate input parameters to the higher level CTMC model. We estimate the expected vessel handling times for several container load and unload profiles and discuss the effect of terminal layout parameters and crane service time variabilities on vessel handling times. From numerical experiments, we find that by having QCs cooperate, the vessel handling times are reduced by up to 15 %. The vessel handling time is strongly dependent on the variation in the QC service time and on the vehicle travel path topology.     

A novel approach to yard planning under vessel arrival uncertainty

Many container terminals in the world adopt the consolidated yard planning strategy, where containers to be loaded into the same vessel are stacked in groups. This has been a good strategy because when a vessel is loading, yard cranes will be stationed at these locations, and the trucks shuttle between the quay cranes and the yard cranes almost in a conveyor belt fashion. These locations are optimally chosen such that no two groups of containers are stacked in close vicinity if they are to be loaded simultaneously. However, when there is a change in vessel arrival schedule, it may cause congestion of trucks at yard locations where groups of containers in near vicinity are loading simultaneously. While the Robust Optimisation community may suggest having a robust plan—a plan that is immune to uncertainty, in this paper, we will like to find a solution that allows us to change easily when uncertainty reveals—a plan that is nimble. While the optimum solution for the nimble plan could be intractable, we explore various heuristics that enable us to find good solutions.     

A new approach to the Container Positioning Problem

In this paper the Container Positioning Problem is revisited. This problem arises at busy container terminals and requires one to minimize the use of block cranes in handling the containers that must wait at the terminal until their next means of transportation. We propose a new Mixed Integer Programming model that not only improves on earlier attempts at this problem, but also better reflects reality. In particular, the proposed model adopts a preference to reshuffle containers in line with a just-in-time concept, as it is assumed that data is more accurate the closer to a container’s scheduled departure the time is. Other important improvements include a reduction in the model size, and the ability of the model to consider containers initially at the terminal. In addition, we describe several classes of valid inequalities for this new formulation and present a rolling horizon based heuristic for solving larger instances of the problem. We show that this new formulation drastically outperforms previous attempts at the problem through a direct comparison on instances available in the literature. Furthermore, we also show that the rolling horizon based heuristic can further reduce the solution time on the larger of these instances as well as find acceptable solutions to much bigger, artificially generated, instances.     

An analytical model for designing yard layouts of a straddle carrier based container terminal

In designing a yard layout for a container terminal several decisions have to be made. In this paper we propose a model which provides decision support for the design of yard layouts of terminals at which straddle carrier are used. We assume that straddle carriers are used for the horizontal transport and the stacking of containers. For the proposed model we develop estimates for the expected cycle distances of straddle carriers. In this case, we distinguish between cycles to landside facilities and to the quay. Numerical results are presented for several parameter settings. For instance, we present results for a comparison of layouts where the rows in the block are orientated parallel with layouts where the rows are orientated perpendicularly to the quay.     

A scheduling problem for a novel container transport system: a case of mobile harbor operation schedule

Mobile Harbor (MH) is a movable floating platform with a container handling system on board so that it can load/discharge containers to/from an anchored container ship in the open sea. As with typical quay crane operation, an efficient schedule for its operation is a key to enhancing its operational productivity. A MH operation scheduling problem is to determine a timed sequence of loading/discharging tasks, assignment of MH units to each task, and their docking position, with an objective of minimizing the makespan of a series of incoming container ships. A mixed integer programming model is formulated to formally define the problem. As a practical solution method to the problem, this paper proposes a rule-based algorithm and a random key based genetic algorithm (rkGA). Computational results show that the rkGA method produces a better-quality solution than the rule-based method, while requiring longer computation time.     

A chassis exchange terminal to reduce truck congestion at container terminals

Truck congestion for container terminals seems to be a worldwide unwanted phenomenon. In this paper we present and analyze a chassis exchange terminal concept to reduce the congestion. The terminal works as a kind of extended gate of a group of traditional container terminals. During the night containers are collected from these container terminals using chassis (or trailers). In daytime these containers on chassis are then collected and exchanged with export containers also on chassis. By exchanging the chassis we avoid extra handling of containers. As connecting and disconnecting to a chassis can be done in a short time, the chassis exchange terminal increases handling capacity substantially during peak hours. In this paper we analyze the concept for the Maasvlakte container terminals in Rotterdam. We investigate both the effect on waiting time, as well as the environmental effects.     

Simulated annealing with different vessel assignment strategies for the continuous berth allocation problem

The berth allocation problem is an optimization problem concerning seaside operations at container terminals. This study investigates the dynamic and continuous berth allocation problem (BAP), whose objective is to minimize the total weighted service time and the deviation cost from vessels’ preferred position. The problem is formulated as a mixed integer programming model. Due to that the BAP is NP-hard, two efficient and effective simulated annealing (SA) algorithms are proposed to locate vessels along the quay. The first SA assigns vessels to available positions along the quay from the left to the right, while the second assigns vessels from both sides. Both small and large-scale instances in the literature are tested to evaluate the effectiveness of the proposed SA algorithms using the optimization software Gurobi and heuristic algorithms from the literature. The results indicate that the proposed SAs can provide optimal solutions in small-scale instances and updates the best solutions in large-scale instances. The improvement over other comparing heuristics is statistically significant.     

A flexible crane scheduling methodology for container terminals

In this paper, we propose a flexible neighbourhood search strategy for quay crane scheduling problems based on the framework of tabu search (TS) algorithm. In the literature, the container workload of a ship is partitioned into a number of fixed jobs to deal with the complexity of the problem. In this paper, we propose flexible jobs which are dynamically changed by TS throughout the search process to eliminate the impact of fixed jobs on the generated schedules. Alternative job sequences are investigated for quay cranes and a new quay crane dispatching policy is developed to generate schedules. Computational experiments conducted with problem instances available in the literature showed that our algorithm is capable of generating quality schedules for quay crane handling operations at reasonable times.     

Pricing storage of outbound containers in container terminals

In container yard of container terminals, a storage charge is imposed to encourage customers to limit the space required for their containers. This study addresses the storage price scheduling problem for the storage of outbound containers. The price schedule consists of the free-time limit, which is the maximum duration for a container to stay in the yard without any charge, and storage charge per day for storing a container past the free-time-limit. Empirical data suggests that the efficiency of loading operations significantly depends on the space utilized by a vessel’s outbound containers. Mathematical models are developed to determine the optimal storage price schedule in such a manner that the terminal’s total profit is maximized or the total system’s cost is minimized. Both single and multi-vessel cases are considered. Properties of the optimal solution are derived from the mathematical models and numerical experiments are conducted to validate solutions.     

A Unique Carboxylic-Acid Hydrogen-Bond Network (CAHBN) Confers Glutaminyl Cyclase Activity on M28 Family Enzymes

Proteins with sequence or structure similar to those of di-Zn exopeptidases are usually classified as the M28-family enzymes, including the mammalian-type glutaminyl cyclases (QCs). QC catalyzes protein N-terminal pyroglutamate formation, a posttranslational modification important under many physiological and pathological conditions, and is a drug target for treating neurodegenerative diseases, cancers and inflammatory disorders. Without functional characterization, mammalian QCs and their orthologs remain indistinguishable at the sequence and structure levels from other M28-family proteins, leading to few reported QCs. Here, we show that a low-barrier carboxylic-acid hydrogen-bond network (CAHBN) is required for QC activity and discriminates QCs from M28-family peptidases. We demonstrate that the CAHBN-containing M28 peptidases deposited in the PDB are indeed QCs. Our analyses identify several thousands of QCs from the three domains of life, and we enzymatically and structurally characterize several. For the first time, the interplay between a CAHBN and the binuclear metal-binding center of mammalian QCs is made clear. We found that the presence or absence of CAHBN is a key discriminator for the formation of either the mono-Zn QCs or the di-Zn exopeptidases. Our study helps explain the possible roles of QCs in life.     

Inbound container storage price competition between the container terminal and a remote container yard

With the rapid development of global ocean transportation, storage space in container terminals is becoming a scarce resource. Hence, the terminal yard only performs as a temporary storage facility for inbound cargos. A storage charge is levied for inbound cargos that stay longer than a free storage time (called free-time-limit). After the free-time-limit, customers may move cargos from the terminal yard to a remote container yard where the storage price is lower than that in the terminal. This paper proposes inbound container storage pricing game models between the container terminal and a remote container yard. Two cases are considered: (1) the inbound container’s dwell time is random and follows a probability distribution function; (2) the inbound container’s dwell time is sensitive to the storage prices. The primary objective of this paper is to analyze the storage pricing behavior and competition outcomes of the container terminal and the remote container yard. A number of insights and analysis are provided.     

Evaluating impact of truck announcements on container stacking efficiency

Container stacking rules are an important factor in container terminal efficiency. We build on prior research and use a discrete-event simulation model to evaluate the impact of a truck announcement system on the performance of online container stacking rules. The information that is contained in the announcement, i.e., the expected departure time for an import container, can be used to schedule pre-emptive remarshall moves. These moves can then be performed when the workload is low in order to decrease the export time and the crane workload at peak times.     

Variation in Aedes aegypti (Diptera: Culicidae) container productivity in a slum and a suburban district of Rio de Janeiro during dry and wet seasons

Seasonal variation in container productivity and infestation levels by Aedes aegypti were evaluated in two areas with distinct levels of urbanization degrees in Rio de Janeiro, a slum and a suburban neighborhood. The four most productive containers can generate up to 90% of total pupae. Large and open-mouthed containers, such as water tanks and metal drums, located outdoors were the most productive in both areas, with up to 47.49% of total Ae. aegypti pupae collected in the shaded sites in the suburban area. Water-tanks were identified as key containers in both areas during both the dry and rainy seasons. Container productivity varied according to seasons and urbanization degree. However, the mean number of pupae per house was higher in the suburban area, but not varied between seasons within each area (P > 0.05). High infestation indexes were observed for both localities, with a house index of 20.5-21.14 in the suburban and of 9.56-11.22 in the urban area. This report gives potential support to a more focused and cost-effective Ae. aegypti control in Rio de Janeiro.     

The environmental impact of container pipeline transport compared to road transport. Case study in the Antwerp Harbor region and some general extrapolations

Purpose  

Increasing mobility demands and growing industrial tissue come with a burden for the environment. Inventive solutions are necessary to address this challenge. This paper compares the environmental impact of two alternative container transportation methods over a 25-year time period for a specific trajectory and transport volume in the Antwerp harbor. One is a pipeline concept; the other a road concept to link the Deurganck dock with the right bank in order to transport 2 million containers per year.     

Seaside operations in container terminals: literature overview,trends, and research directions

Seaside operations are considered the bottleneck operation in most container terminals around the world. This paper presents an in-depth updated overview of the seaside operations at container terminals and highlights current trends and developments. We review and classify scientific journal papers on container terminal seaside operations, published between 2004 and 2012. The paper also discusses and challenges the current operational paradigms on seaside operations. Lastly, the paper identifies new avenues for academic research based on current trends and developments in the container terminal industry.     

Habitat stability and the larval mosquito community in treeholes and other containers on a temperate Island

The temporal fluctuation of water levels and the presence of mosquito larvae were investigated for four types of small container habitats (treeholes, bamboo stumps, cemetery stone vases, and cemetery stone vessels) on Kabeshima Island in Kyushu, southwestern Japan. The probability that containers held water was positively correlated with the quantity of the preceding rainfall and with the depth and volume of the containers. It was estimated that dehydration occurred more regularly in autumn and winter than in summer. The probability that mosquito larvae were present in each type of container was positively correlated with habitat stability in terms of the probability of the existence of standing water and the coefficient of variation of the water level. Twelve species of mosquito larvae, including two rare predators, were found. Species composition differed between the different types of container. Although 4 to 10 species used each type of container, the median number of species per container was two for treeholes and bamboo stumps, and one for the others. The dominant species wasTripteroides bambusa in treeholes and bamboo stumps,Aedes albopictus in stone vases, andA. japonicus in stone vessels. The larval mosquito community, which lacked major predators, possessed the following features that may facilitate the coexistence of many species: (1) niche segregation amongst species in terms of their selection of container types; (2) an aggregated distribution of the individual species among containers of the same type; (3) high intraspecific mean crowding (and hence probably intense intraspecific competition) in the dominant species in each type of container; (4) independent species associations within the same type of container; and (5) low interspecific mean crowding (and hence probablynot intense interspecific competition) between species in the same type of container.     

Inter-terminal transportation: an annotated bibliography and research agenda

The seemingly unlimited growth of containerized transport is nowadays associated with an increasing number of seaport container terminals and facilities as well as demand for port-centric value-added and just-in-time logistics services. Intense global and local competition as well as geographical limitations urgently require efficient means to handle inter-terminal transportation. Many factors influence the productivity and efficiency of inter-terminal transportation as well as its economic and environmental implications. In the last two decades, these aspects have led to a growing interest in research, in particular concerning decision analytics and innovative information technology aiming to better understand, improve, and operate inter-terminal transportation. In this paper, we present a chronological overview of related works as an annotated bibliography in order to reflect the current state of research. Furthermore, we identify future research issues and propose a respective research agenda.     

Aligning barge and terminal operations using service-time profiles

We consider a key issue in hinterland container navigation in ports, such as Rotterdam and Antwerp, namely the barge handling problem: how to optimize the alignment of barge and terminal operations in a port. We make a major step in solving the barge handling problem for practical settings. Specifically, we consider restricted opening times of terminals, unbalanced networks, the presence of sea vessels, and closing times of containers. Consequently, at a terminal a barge faces time dependency in: (1) the waiting time until the start of handling and (2) the handling time itself. The concept of waiting profiles which we introduced in an earlier paper only deals with (1). To deal with (1) and (2) together we introduce a more comprehensive concept, namely that of service-time profile. To establish how well our approach works, we evaluate the performance of our distributed planning approach extensively by means of simulation. We compare our results with those based on centralized planning by using an off-line benchmark resembling it. We show that the Multi-Agent system that we introduce enables barge and terminal operators to align their operations efficiently. Hence, it can be seen as a promising solution approach for solving the barge handling problem, since it enables (competing) companies to collaborate in a competitive way.     

Strategies for improving a long-established terminal’s performance: a simulation study of a Turkish container terminal

Due to a long-lasting increase in global trade, only interrupted by the late-2000s economic crisis, container traffic has grown dramatically. As a result, new terminals have opened and existing terminals face much higher container handling than before. In order to meet these challenges, one of the biggest container terminals in Turkey has begun to reconsider its terminal operations and to achieve improvements of its overall logistics performance. Because the factors impacting the terminal’s performance are highly interrelated, a simulation model was developed to analyze the terminal operations, to identify potential bottleneck resources and to highlight directions for the future development of the configuration and the operational control system. For a long-established terminal like the one considered in this study the options for improving the overall performance are limited by the geographical dimensions and by the existing terminal equipment. By use of the simulation model the terminal operations are evaluated under different workload scenarios and alternative configurations are tested in order to support strategic decisions on the terminal’s development.