Coordinating Pricing and Empty Container Repositioning in Two-Depot Shipping Systems

This paper studies joint decisions on pricing and empty container repositioning in two- depot shipping services with stochastic shipping demand. We formulate the problem as a stochastic dynamic programming (DP) model. The exact DP may have a high-dimensional state space due to in-transit containers. To cope with the curse of dimensionality, we develop an approximate model where the number of in-transit containers on each vessel is approxi- mated with a fixed container flow predetermined by solving a static version of the problem. Moreover, we show that the approximate value function is L♮-concave, thereby characterizing the structure of the optimal control policy for the approximate model. With the upper bound obtained by solving the information relaxation-based dual of the exact DP, we numerically show that the control policies generated from our approximate model are close to optimal when transit times span multiple periods

Port choice: A frequency-based container assignment model

The process of containerization has connected the world with a cost-effective freight service, successfully forming a competitive global market. Mixed freight shipping has changed dramatically due to containerization and globalization. The port system has experienced a tough time keeping pace with globalisation in terms of its roles and functions in liner shipping. Consequently, port choice has become a challenging problem to analyse with many stakeholders and complex circumstances. The literature formulating the basis of this maritime container assignment model can be identified as a combination of port choice modelling, a freight flow model and empty container repositioning. It is observed that the maritime container assignment problem shares a greater affinity with transit assignment than with traffic assignment conventionally applied freight in the four step approach, because containers are generally carried by shipping lines which operate services on fixed routes or port rotations. A model capable of representing full and empty container flows at a global level would be useful to almost every stakeholder in the container liner shipping industry, such as shippers, shipping lines, port authorities, terminal operating companies, regional and national planning authorities, marine insurance companies, and others. The classic frequency-based transit assignment approach of Spiess and Florian is transferred and applied to maritime containers as the foundation for a global maritime container assignment model. The first version of this model assigned full and empty containers to routes to minimise expected travel time, which consists of sailing time between ports and dwell time at intermediate transhipment ports. Service frequency and port capacity influence the pattern of full and empty container flows and therefore port choice. In this thesis, the model is further developed to fit the reality of container liner shipping by minimising expected cost rather than expected travel time. The objective is now to assign container flows to routes to minimize the sailing costs and expected dwell costs at the origin port and intermediate transhipment ports. The constraints included are extended to include the maximum number of containers each route can carry. Finally, the capabilities of the cost-based container assignment model are explored through a case study of the Europe-Far East trade lane. A range of strategy and policy options, such as a shipping line planning a new route or modifying an existing route and a port authority considering expansion, are simulated. A possible approach to model validation through independent data is proposed. Recommendations for future research are provided at the end of the thesis. Many aspects are covered in the thesis; an origin-destination matrix estimation, automated virtual (task) network construction from routes and schedules, improvements to the probability distribution used for ship arrivals, a validation procedure, and model extension from port-to-port movements to door-to-door container movements

Liner shipping speed and bunkering management under stochastic environment

Ph.DDOCTOR OF PHILOSOPH

Liner ship fleet planning with uncertain container shipment demand

Ph.DDOCTOR OF PHILOSOPH

Slow-Steaming Climate Strategies For Abatement Efforts In Maritime Shipping

Maritime shipping is a major contributor to climate change – accounting for 2.89\% of Global CO2 emissions in 2018. Given the “light hand” of regulatory institutions governing commercial activities on the high seas, attempts to reduce the emissions of ocean-going ships have not been successful. In this thesis, the impacts of emission policies and incentives for cooperation in the international maritime shipping industry are examined. The International Maritime Organization (IMO) – the regulator – GHG Strategy puts forth both “speed optimisation” and “speed reduction” as candidate measures for short-term emission abatement. These terms are poorly defined, however, leading to different interpretations. Slow steaming, or deliberately reducing ships’ speed, allows firms to decrease fuel consumption and therefore, emissions. Grounded in this rationale, a flexible numerical simulation model is developed for a market comprised of heterogeneous shipping companies to investigate maritime shipping abatement dynamics under various slow steaming policies. First, we project firms' business-as-usual (BAU) operations and then analyse both policies: Speed reduction – relative to BAU levels and Speed optimisation – as firms' climate strategy response to meet various emission caps. The simulation results suggest that firms already slow-steam when economically optimal (i.e. by evaluating the trade-off between fuel savings and time-dependent operating costs). Even more so, they show that speed optimization -as an abatement strategy- provides firms with the flexibility to derive their optimal Slow-Steaming rates to sustain a regulator's environmental policy. In contrast, we find that Slow-Steaming - as a command and control policy- shifts regulatory focus and is difficult to enforce in international waters. The simulation model was also used to analyze a two-stage, cooperative game of coalition formation with heterogeneous firms and individual abatement strategies. In the first stage, firms decide whether to join a coalition or not (membership decision). Coalition signatories adopt the operational slow-steaming climate strategy over the planning horizon and choose the abatement levels that maximise the sum of their payoffs under a joint emission budget constraint. On the other hand, non-signatories to the coalition (singletons) optimise their own abatement level by maximizing individual payoffs, subject to their own individual caps. Our results indicate that cooperation allows firms with heterogeneous abatement cost curves to pool resources and properly allocate speed reduction endeavours to sustain an emission target. Thus, industry-level climate strategies withhold the potential to improve environmental sustainability through cooperation for ocean shipping