This paper presents the flexible containership loading problem for seaport container terminals. The integrated management of loading operations, planning of the transport vehicles to use and their scheduling is what we define as the Flexible Ship Loading Problem (FSLP). The flexibility comes from a cooperative agreement between the terminal operator and the liner shipping company, specifying that the terminal has the right to decide which specific container to load for each slot obeying the class-based stowage plan received from the liner. We formulate a mathematical model for the problem. Then we present various modelling enhancements and a mathematical model to obtain strong lower bounds. We also propose a heuristic algorithm to solve the problem. It is shown that enhancements improve the performance of formulation significantly, and the heuristic efficiently generates high-quality solutions. Results also point out that substantial cost savings can be achieved by integrating the ship loading operations.
This study introduces a state-of-the-art volatility forecasting method for container shipping freight rates. Over the last decade, the container shipping industry has become very unpredictable. The demolition of the shipping conferences system in 2008 for all trades calling a port in the European Union (EU) and the global financial crisis in 2009 have affected the container shipping freight market adversely towards a depressive and non-stable market environment with heavily fluctuating freight rate movements. At the same time, the approaches of forecasting container freight rates using econometric and time series modelling have been rather limited. Therefore, in this paper, we discuss contemporary container freight rate dynamics in an attempt to forecast for the Far East to Northern Europe trade lane. Methodology-wise, we employ autoregressive integrated moving average (ARIMA) as well as the combination of ARIMA and autoregressive conditional heteroscedasticity (ARCH) model, which we call ARIMARCH. We observe that ARIMARCH model provides comparatively better results than the existing freight rate forecasting models while performing short-term forecasts on a weekly as well as monthly level. We also observe remarkable influence of recurrent general rate increases on the container freight rate volatility.
The maritime sector contributes significantly to climate change, given thenumber of global emissions that this represents. Emissions inventorying isone of the measurement system approaches considered in terminals to mitigate harmful emissions. The concept of sustainability has gained attentionwhere economic, social, and environmental dimensions need to be balanced.Assessing all three sustainability dimensions is important. Both the environment and the society, e.g., human health and safety, are impacted by terminal operations. Reducing their negative impact can compromise the economicgrowth of the terminal. This is challenging the maritime sector, and althoughsome authors define methods to evaluate sustainability in terminals, nostandard guideline is available in the literature. The lack of a common reference guideline makes comparison of sustainability actions in terminals difficult.This paper presents a sustainability assessment framework based on theanalysis of the state of the art in literature contributing to sustainable development of terminals and supporting decision-makers.
The literature on climate change in the maritime transport industry has grown rapidly in the last few years. Yet as the research agenda has progressed, scientific debates have become more isolated and fragmented, making it difficult to translate new findings into broader policy debates. This article draws on problematization methodology to help organize the scientific debate on maritime emissions and to identify analytical gaps and challenges. We argue that scholars investigate shipping's emission problem from four distinct analytical perspectives— (1) international laws and regulations, (2) markets and economics, (3) engineering and technology, and (4) authority and legitimacy. Each of these perspectives problematizes maritime emissions in specific ways, leading to different policies and strategies to address the problem. We call for better integrating these four literatures and highlight three crosscutting areas and problems for future research. First, developing institutions that facilitate market and engineering solutions; second, integrating climate mitigation and adaptation research; and third, focusing on justice concerns to ensure an equitable green transition in the maritime industry.
Small-scale fishing communities along Cambodia's coast have relied on marine resources as a mainstay of their livelihood for many decades. However, in the past 10 to 15 years, environmental change, increased fishing pressure, illegal, underreported, and unregulated fishing, and sand mining have contributed to a progressive decline in their catch. At the same time, economic opportunities outside the coastal village have acted as a draw and catalyzed migration to secondary cities and to the capital. This study examines out-migration of people from coastal communities to the city of Koh Kong. Using qualitative data collected from three fishing villages, I explore why people leave and why others stay in the village. In the context of city provisioning systems, the study also reveals a shift in climate-related vulnerability for coastal village migrants when they become urban residents. The study highlights the importance of looking not only at city planning, infrastructure challenges, and climate risks but also at the attendant social effects that phenomena such as migration have on people who are increasingly on the move. Such a perspective offers a more people-centred understanding of urban climate resilience in Cambodia, and potentially for other countries across Southeast Asia.
Product-based companies worldwide attempt to integrate services into their offerings, embarking on “servitization” as a key strategy. These days, the acceleration of technological innovation (i.e., Industry 4.0) has triggered an emerging IT-driven business paradigm called digital servitization or smart product-service system (PSS) that embeds Industry 4.0 technologies. As a result of these developments, related literature has expanded across different disciplines in recent years. However, understanding and describing literature is not easy considering its volume and variety. Establishing common ground for central concepts is essential for science. Thus, to clarify important topics and research issues on servitization and PSSs in Industry 4.0, we carry out a comprehensive literature review by performing text mining of 419 journal articles. A machine learning approach is applied to learn and identify the specific topics, and the suggested key references are manually reviewed to develop a state-of-the-art overview. A total of 10 key research topics are identified, and the enabler–engineering–goal framework is developed. This study contributes to clarifying a systematized view of dispersed studies of servitization and PSSs in Industry 4.0 across multiple disciplines and encourages further academic discussions and industrial transformation.
As the emission legislation becomes further constraining, all manufacturers started to fulfill the future regulations about the prime movers in the market. Lean-burn gas engines operating under marine applications are also obligated to enhance the performance with a low emission level. Lean-burn gas engines are expressed as a cleaner source of power in steady loading than diesel engines, while in transient conditions of sea state, the unsteadiness compels the engine to respond differently than in the steady-state. This response leads to higher fuel consumption and an increase in emission formation. In order to improve the stability of the engine in transient conditions, this study presents a concept implementing a hybrid configuration in the propulsion system. An engine model is developed and validated in a range of load and speed by comparing it with the available measured data. The imposed torque into the developed engine model is smoothed out by implementing the hybrid concept, and its influence on emission reduction is discussed. It is shown that with the hybrid propulsion system, the NOX reduces up to 40% because of the maximum load reduction. Moreover, eliminating the low load operation by a Power Take In during incomplete propeller immersion, the methane slip declines significantly due to combustion efficiency enhancement.
This paper investigates the simultaneous optimization problem of routing and sailing speed in the context of full-shipload tramp shipping. In this problem, a set of cargoes can be transported from their load to discharge ports by a fleet of heterogeneous ships of different speed ranges and load-dependent fuel consumption. The objective is to determine which orders to serve and to find the optimal route for each ship and the optimal sailing speed on each leg of the route so that the total profit is maximized. The problem originated from a real-life challenge faced by a Danish tramp shipping company in the tanker business. To solve the problem, a three-index mixed integer linear programming formulation as well as a set packing formulation is presented. A novel Branch-and-Price algorithm with efficient data preprocessing and heuristic column generation is proposed. The computational results on the test instances generated from real-life data show that the heuristic provides optimal solutions for small test instances and near-optimal solutions for larger test instances in a short running time. The effects of speed optimization and the sensitivity of the solutions to the fuel price change are analyzed. It is shown that speed optimization can improve the total profit by 16% on average and the fuel price has a significant effect on the average sailing speed and total profit.
In this paper, the nonlinear interaction of regular water waves propagating over a fixed and submerged circular cylinder is numerically studied. At the structure’s lee side, the free surface profile experiences strong nonlinear deformation where the superharmonic free wave generated can be significant and is superposed on the transmitted wave. The wave profile then becomes asymmetric and skewed and may eventually reach the point of physical wave breaking. The governing equation and boundary conditions of this wave–structure interaction problem are formulated using both the fully nonlinear and the weak-scatterer theory. The corresponding boundary value problem is numerically solved by the immersed-boundary adaptive harmonic polynomial cell solver. In this study, a pragmatic wave-breaking suppression model is incorporated into the original solver. Both the harmonic free wave amplitudes at the structure’s lee side and the harmonic vertical forces on the cylinder are studied. The simulated harmonic wave amplitudes are compared to other published experiments and theoretical data. In general, good agreement is achieved. The effects of the incorporated wave-breaking suppression model on the simulated results are discussed. In our study, the incorporation of the pragmatic wave-breaking suppression model successfully extends the capabilities of the original fully nonlinear immersed-boundary adaptive harmonic polynomial cell solver.
The typical approach for generating nonlinear waves in physical models involves employing first- or second-order wave theory, requiring a large water depth at the wavemaker. When the prototype bathymetry shows a gentle slope, a large facility is required. However, practical constraints often make this unfeasible, leading to the use of steep transition slopes to obtain sufficient water depth at the generator. Incorporating a transition slope may generate unwanted free waves beyond the transition point, significantly impacting the wave parameters. The presence of these free waves causes the response of the tested structure to deviate from that found in the prototype. This paper offers guidelines for using transition slopes effectively while avoiding the generation of unwanted free waves after the transition point.