Roar Adland  David Hansson  Levin von der Wense 《Maritime Policy and Management》2017,44(7):803-814

The seaborne oil transportation market is served by two main types of vessels—crude oil tankers and product tankers. Product tankers are designed to move refined oil products, yet they can also opportunistically carry ‘dirty’ products such as crude and heavy fuel oil, subject to the cost of tank cleaning when re-entering the clean products trade. We apply an entry-exit real option model with a stochastic freight rate differential to derive optimal triggers for switching between the two cargo types and estimate the value of the switching option. We show that the value of active switching has grown over time, and generally exceeds the additional construction cost of a product tanker. Our findings are important both from a practical point of view and for our understanding of market integration in the tanker freight market. Specifically, shipowners can use our model as a basis for optimizing chartering policy for clean product tankers. We also show that there are periods where the dirty market is persistently stronger, and discuss the possible reasons for such apparent inefficiencies.  相似文献   

    

David Glen 《Maritime Policy and Management》2013,40(5):475-487

This article presents the results of modelling the behaviour of oil spill numbers published by the International Tanker Owners Pollution Federation over the period 1970 to 2005. Poisson count or negative binomial models are estimated to identify the major determinants of oil spill numbers over this period. The results are used to estimate the number of oil spills that would have occurred in the absence of the adoption of double hull technology. Other potential factors, such as changes in the regulatory regimes regarding oil transportation, were found to be insignificant.  相似文献   

    

Ann-Margaret Esnard  David Brower  Bruce Bortz 《Coastal management》2013,41(1):53-72

This article provides a summary of past disasters, and hazard mitigation initiatives in the state of North Carolina, with a focus on the barrier island of Nags Head. The article also highlights the application of GIS technology to assess (i) the built environment and the extent of development and tax base in the \"danger\" zones (floods, oceanfront hazard zone, incipient inlets); (ii) the status of pre-Flood Insurance Rate Mapping (FlRM) structures on developed parcels; and (iii) vacant land in relation to current zoning. Findings show that 72% of Nags Head was developed, with close to one-third of the developed parcels within the oceanfront hazard zone. A relatively high percentage of structures built prior to Nags Head's regular participation in the Flood Insurance Rate Mapping (FIRM) program also lie within incipient inlets and VE flood zones. These findings were used as part of Nags Head's ongoing hazard mitigation initiatives.  相似文献   

    

Christopher de Saxe  David Cebon 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2019,57(5):752-776

High-capacity vehicles have been shown to be highly effective in reducing emissions associated with road freight transport. However, the reduced manoeuvrability of long vehicles often necessitates the use of active trailer steering. Path-following trailer steering systems are very effective in this regard, but are currently limited to on-highway applications due to the manner in which trailer off-tracking is estimated. In this work, a novel trailer off-tracking measurement concept is introduced which is independent of wheel slip and ground surface conditions, and requires no additional sensor measurements or parameter data from the tractor. The concept utilises a stereo camera pair affixed to the trailer and a visual odometry-based algorithm to calculate off-tracking. The concept was evaluated in detailed simulation and full-scale vehicle tests, demonstrating its feasibility and highlighting some important characteristics. RMS measurement errors of 0.11–0.12?m (3.3–3.6%) were obtained in a challenging visual environment.  相似文献