28 research outputs found
Strategic maritime container transport design in oligopolistic markets
AbstractThis paper considers the maritime container assignment problem in a market setting with two competing firms. Given a series of known, exogenous demands for service between pairs of ports, each company is free to design a liner service network serving a subset of the ports and demand, subject to the size of their fleets and the potential for profit. The model is designed as a three-stage complete information game: in the first stage, the firms simultaneously invest in their fleet; in the second stage, they individually design their networks and solve the route assignment problem with respect to the transport demand they expect to serve, given the fleet determined in the first stage; in the final stage, the firms compete in terms of freight rates on each origin-destination movement. The game is solved by backward induction. Numerical solutions are provided to characterize the equilibria of the game
Strategic maritime container service design in oligopolistic markets
AbstractThis paper considers the maritime container assignment problem in a market setting with two competing firms. Given a series of known, exogenous demands for service between pairs of ports, each company is free to design liner services connecting a subset of the ports and demand, subject to the size of their fleets and the potential for profit. The model is designed as a three-stage complete information game: in the first stage, the firms simultaneously invest in their fleet; in the second stage, they individually design their services and solve the route assignment problem with respect to the transport demand they expect to serve, given the fleet determined in the first stage; in the final stage, the firms compete in terms of freight rates on each originâdestination movement. The game is solved by backward induction. Numerical solutions are provided to characterize the equilibria of the game
Probabilistic Planning for Maritime Search and Rescue
Maritime accidents cause thousands of disappearances every year, with migrant
crossings being particularly dangerous and under-reported. Current coastal and
NGO search and rescue services are unable to provide a timely response, so new
technologies such as autonomous UAVs are needed. We present a thorough
formalization of the maritime search and rescue problem considering its
time-critical and probabilistic nature. Further, we introduce a method for
determining the optimal search altitude for any aerial thermal-based detection
system, so as to maximize overall mission success.Comment: 4 pages. 3 figures. To appear in 6th International Conference on
Dynamics of Disasters (DOD 2023
Long-range collision avoidance for shared space simulation based on social forces
Shared space is an innovative approach to improve environments where both pedestrians and vehicles are present, with integrated layouts to balance priority. The Social Force Model (SFM) was used to visualise pedestrian and car trajectories so that peaks of density and pressure at critical locations are avoided. This paper extends the SFM to consider a long-range collision detection and collision resolution strategy. The determination of potential conflicts is enhanced using principle component analysis for a set of agent's prior speeds and directions. This long-range collision avoidance strategy results in more realistic SFM-based trajectories for pedestrians and cars in shared spaces
Modelling the impact of liner shipping network perturbations on container cargo routing: Southeast Asia to Europe application
Understanding how container routing stands to be impacted by different scenarios of liner shipping network perturbations such as natural disasters or new major infrastructure developments is of key importance for decision-making in the liner shipping industry. The variety of actors and processes within modern supply chains and the complexity of their relationships have previously led to the development of simulation-based models, whose application has been largely compromised by their dependency on extensive and often confidential sets of data. This study proposes the application of optimisation techniques less dependent on complex data sets in order to develop a quantitative framework to assess the impacts of disruptive events on liner shipping networks. We provide a categorization of liner network perturbations, differentiating between systemic and external and formulate a container assignment model that minimises routing costs extending previous implementations to allow feasible solutions when routing capacity is reduced below transport demand. We develop a base case network for the Southeast Asia to Europe liner shipping trade and review of accidents related to port disruptions for two scenarios of seismic and political conflict hazards. Numerical results identify alternative routing paths and costs in the aftermath of port disruptions scenarios and suggest higher vulnerability of intra-regional connectivity
Feasibility of Equity-driven Taxi Pricing Strategy based on Double Auction Mechanism in Bangkok Metropolitan Region, Thailand
Passenger rejection by taxi drivers impacts the travel behaviour in many
cities and suburban areas, often leaving those potential customers in
non-popular zones stranded without access to taxis. To overcome this problem,
many practices have been implemented, such as penalties to drivers, bans, and
new pricing strategies. This paper presents a double auction taxi fare scheme,
which gives both passengers and taxi drivers to influence the price, coupled
with a clustering method to discourage strategic service rejection in the case
study of Bangkok Metropolitan Region, Thailand, which has detailed data
availability and uneven taxi journey distributions. The double auction
mechanism is tailored to 2019 taxi trips, service rejection complaints, and
local travel behaviour to boost transportation equity. To benchmark the
performance of the new double auction scheme, a bespoke agent-based model of
the taxi service in Bangkok Metropolitan Region at different rejection rates of
0%-20% was created. On one hand, the current rejection behaviour was modelled,
and on the other, the double auction pricing strategy was applied. The results
indicate that the double auction strategy generates a spatially distributed
accessibility and leads to a higher taxi assignment success rate by up to 30%.
The double auction scheme increases pickups from locations that are 20-40 km
from central Bangkok by 10-15%, despite being areas of low profit. Due to the
changing taxi travel landscape and longer taxi journeys, the total air
pollutant emissions from the taxis increase by 10% while decreasing local
emissions within central areas of Bangkok by upto 40%. Using a 5 Baht average
surcharge, the total revenue drops by 20%. The results show that an
equity-driven pricing strategy as an implementation of transport policy would
be beneficial.Comment: 21 pages, 10 figures, 1 table, as accepted at Transportation Research
Board Conference 202
Uncertainty-aware assignment techniques for automated guided vehicles in maritime cotainer terminals
EThOS - Electronic Theses Online ServiceGBUnited Kingdo