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ABSTRACTPort activity plays an important role in facilitating international trade. Sufficient capacity is indispensable for a port to attract flows to a region and retain them. The capacity decision is the result of a trade-off between investment and waiting costs. Traditional methods to value expansion projects do not deal adequately with managerial flexibility in the face of uncertainty from different sources in the complex port environment. In this paper, real options (RO) models are identified as an alternative method to making project valuations and investment decisions, as they attribute the correct value to managerial flexibility under uncertainty. In order to be able to build and use such RO models for port capacity investment decisions, the sources and implications of uncertainty in the port and the different RO model specifications need to be understood. To this end, both the literature about uncertainty in the port context and the literature about real options models are reviewed in order to provide researchers who want to build their own decision-making models, with the necessary knowledge of both fields. The review makes clear that the complex interactions in and competition between the logistics chains and their actors coming together in ports have significant impacts on port capacity. Uncertainty is also caused by uncertain international trade flows and changes in legislation following new technologies and environmental impacts. An analysis of the components of some general RO models shows how the options of flexible output, investment size and timing are valued by RO models in a setting with demand uncertainty. Moreover, the review presents researchers with insights in how to deal with cooperative and competitive interactions in the chain, time to build, cyclical markets and legislation changes. It also shows how to value the expansion and the phased investment options. The new insights resulting from this review are subsequently combined in a framework that serves as a guideline to build RO models for port capacity investments. Finally, an exemplifying application of the framework is used to build an actual port capacity investment decision model. 相似文献
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Industry design standards such as BS 7910 deployed some empirical formulas for the prediction of stress intensity factor (SIF) based on simulation results from ... 相似文献
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Matteo Del Chicca 《WMU Journal of Maritime Affairs》2012,11(1):83-93
Before searching for new legal solutions to manage maritime piracy problems, especially those related to jurisdiction, it
is essential to examine and analyse the existing international legal framework to determine whether current international
legal instruments are already appropriate to face off this threat. One such principle is the “Aut dedere aut iudicare” principle, which has been also codified into SUA Convention, at art. 6 par. 4. This obligation comes from an international
treaty, so it cannot be disregarded by any state (short of becoming susceptible to international liability), neither can it
be amended by a national law. If a state party has inadequate law resources to establish its jurisdiction, or if unable or
unwilling to prosecute the pirate, then such state party has no choice but extradite the pirate. If we consider the above
principle as a conventional obligation, then it should be limited only to state parties, and it should be applied only under
conditions stated by SUA Convention. Instead, if we consider it as a customary law principle, because piracy—as crimen iuris gentium—offends international community as a whole, then such principle shall be binding without any limit or condition. 相似文献
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Thomas Spenkuch Stephen R. Turnock Matteo Scarponi R. Ajit Shenoi 《Journal of Marine Science and Technology》2011,16(2):115-128
An approach for enhancing the realism of yacht fleet race simulations based on a lifting line method is developed. The wake
of an upwind sailing yacht is represented as a single heeled horseshoe vortex and image system. At each time step, changes
in vortex strength are convected into the wake as a pair of vortex line elements. These subsequently move in accordance with
the local wind, the self-induced velocity and the velocity induced by the presence of the wakes of other yachts. In addition,
the lifting line model has a model for the viscous wake due to the drag associated with the yacht and its sails superimposed
on it. A synthesis of sail yacht wake representations based on detailed 3D Reynolds-averaged Navier–Stokes computational fluid
dynamics calculations with wind tunnel test results is used to capture the initial strength of the combined main-jib vortex
system and its vertical height. The implementation of the lifting line algorithm within Robo-Race, a real-time yacht race strategy analysis tool, is described. Two upwind race interaction case studies are presented, and
these show that the newly implemented wake model makes an important contribution to enhancing the realism of the sailing simulation. 相似文献
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AbstractCoastal borderlands are subjected to particular socioeconomic, political and environmental dynamics in Europe and worldwide. The presence of the international boundary in these areas poses challenges in the process of Integrated Coastal Zone Management (ICZM). The aim of this paper is to explore the existence, characteristics and the role that local cross-border cooperation plays in transboundary coastal zone management as well as the resulting potentialities of local endogenous development for improving the management and governance of the tourism sector, coastal development, fisheries and marine protected areas in the Albera Marítima (Northwestern Mediterranean). The applied methods included document review, statistical information and semi-structured interviews. The research shows that local agents are not capable of developing a stable cross-border network due to persisting lack of trust, weak joint strategic vision and high competitiveness in sectors like fishery and tourism. Based on particularly interesting initiatives occurred in Albera Marítima and other successful experiences in Mediterranean coastal borderlands, a proposal has been made to implement several measures, including a transboundary integrated coastal plan, the joint observatory of fishery resources and a scientific network platform. For the aforementioned issues, the study contributes to the ICZM literature by providing a new perspective on local transboundary cooperation. 相似文献
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MUSSONE Lorenzo 《交通运输系统工程与信息》2013,13(4):84-93
以道路网络的路段流量为基础进行OD分布矩阵估计.与以往文献不同的是本文应用了多层前馈神经网络的方法.由于路段流量与相关的OD矩阵分布之间存在连续性关系,这为神经网络模型的逼近特性提供了可行性.本文的方法适用于OD分布矩阵的实时校正.在已知OD分布矩阵的前提下,对两种情境———试验网络和实际Naples农村道路网进行仿真分析.主成分分析法的应用减少了变量个数并有利于改进输入数据.估计误差相对较低,与分析方法相反的是处理的时间几乎是实时的,因此这种方法可用于动态交通管理.本文的神经网络方法在误差和计算时间方面优于传统商业软件得到的OD估计结果. 相似文献
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Matteo Massaro Edoardo Marconi 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(4):604-620
The effect of engine spin direction on the dynamics of powered two wheelers is investigated in terms of steady-state points (equilibria), vibration modes (stability), manoeuvre time (performance/manoeuvrability) and handling. The goal is to assess and quantify the advantage sometimes claimed for the ‘counter-rotating’ engine configuration, where the engine spins in the opposite direction with respect to wheels, against the ‘conventional’ configuration, where the engine spins in the same direction of wheels. 相似文献
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Matteo Diez Wei He Emilio F. Campana Frederick Stern 《Journal of Marine Science and Technology》2014,19(2):143-169
A framework for assessing convergence and validation of non-intrusive uncertainty quantification (UQ) methods is studied and applied to a complex industrial problem in ship design, namely the high-speed Delft Catamaran advancing in calm water, with variable Froude number and geometry. Relationship between UQ studies and deterministic verification and validation is discussed. Computations are performed using high- (URANS) and low- (potential flow) fidelity simulations. Froude number has expected value and standard deviation equal to 0.5 and 0.05, respectively, on a truncated normal distribution. Geometric uncertainty is related to the research space of a simulation-based design optimization, and assessed through the Karhunen–Loève expansion (KLE). Monte Carlo method with Latin hypercube sampling (MC-LHS) is used to compute expected value, standard deviation, distribution and uncertainty intervals for resistance, sinkage and trim. MC-LHS with CFD is used as a benchmark for validating less costly UQ methods, including MC-LHS with metamodels and standard quadrature formulas. Gaussian quadrature is found the most efficient method; however, MC-LHS with metamodels is preferred since provides with confidence intervals and distributions in a straightforward way and at reasonably small computational cost. UQ results are compared to earlier deterministic single- and multi-objective optimization; reduced-dimensional KLE studies for geometric variability indicate that stochastic optimization would not be of great benefit for the present problem. 相似文献
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The objective of this paper is to propose a method, based on the image processing of field survey data, to analyze vehicles movements into roundabouts. This research study consisted of three stages: a field survey to collect vehicular flow images captured by video cameras, the processing of these images using a proprietary software (VeTRA—Vehicle Tracking for Roundabout Analysis), and finally, the analysis of the collected data. The main feature of the software is that it allows the automatic computation of the main variables necessary to rank and evaluate a generic roundabout: the entry/exit (E/E) matrix with classification of vehicles (e.g., heavy, light, and motorbikes), vehicle trajectories, and vehicular speed diagrams along the paths inside the roundabout. The processing system is robust enough to withstand classic problems affecting image processing such as variable wind conditions, cloud cover, shadows, and obstructions. Calibration and error evaluation have been deduced from data collected by a high precision Real Time Kinematic GPS video recording system mounted on a probe vehicle. Data of E/E matrices generated by VeTRA are compared with those manually counted on the corresponding video images. A case study of an existing roundabout is featured in the paper. The results indicate that the software has a high capability of generating the E/E matrix. The analysis of vehicular trajectories with both the plot of curvature diagrams and the corresponding speed diagrams enable the evaluation of driver behavior relative to the geometric shape of the roundabout. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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