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21.
Floriano Pires 《Maritime Policy and Management》2013,40(7):831-844
ABSTRACTThe literature on valuation of time charter contracts and real options in shipping generally relies on the complete markets hypothesis and the risk-neutrality of agents. However, these assumptions fail completely in some shipping market segments. This study proposes a numerical approach—based on discounting the certainty equivalent payoff at the risk-free rate—which incorporates the agent’s risk preferences through an exponential utility function. The method comprises an iterative Monte Carlo nested simulation with the real probability measure. This method is applied to a case of Suezmax tankers. The stochastic evolution of the time charter rates is modelled as a geometric mean-reverting process. The case study supports the applicability of the proposed method and evidences that the effect of risk preference may be significant, mainly for more risk-averse agents. Although the method involves intensive computation, it has the benefits of theoretical ease and flexibility, which could encourage utilisation by practitioners. 相似文献
22.
Recently, policy makers’ expectations about the role of electric cars in reducing emissions have risen substantially. In parallel, academic research on purchase intentions has dramatically increased. Originally, most studies have focused on utility attributes and price. More recently, several hybrid choice models have been estimated to include the impact of attitudes on choice probabilities. In addition, a few studies have caught the attention to social influence. In contributing to this line of research, this paper reports the results of an expanded hybrid choice, which simultaneously estimated all these different effects in a single integrated model of purchase intention. Results indicate that the model performs well. Costs considerations contribute most to the utility of electric cars. Social influence is less important, but there is also evidence that people tend to take it into consideration when there are positive public opinions about electric cars and the market share becomes almost half of friends of their social network. The intention to purchase an electric car is also influenced by attitudes about environmental concerns and technology acceptance. 相似文献
23.
Ruichun HE Yinzhen LI Junyi ZHANG Fujiwara Akimasa 《Journal of Transportation Systems Engineering and Information Technology》2007,7(6):80-84
Transport planners often need to forecast the influence of the transport policies on travel demand, e.g., construction of a new transport alternative, changing public transit fares, or imposing road pricing schemes. Stated preference (SP) surveys are frequently adopted by transport planners for the analysis of the impact of transport policies on travel demand. However, evidence suggests that preferences derived from SP surveys are contingent on context, which indicates that trip makers may show asymmetric preferences for different levels of services. The objective of this article is to propose an alternative conceptual framework for travel demand analysis. It is expected that travel behavior may be heterogeneous across trip makers; response (or parameter of) to the level of service is defined as a function of the attributes of the trip makers. It is also aimed to propose some urban transportation policies based on a new type of discrete choice model. In an empirical demonstration, the panel data obtained from commuters in Lanzhou, China, are used, and support is obtained for several predictions on why behavioral intentions are, or are not, implemented. 相似文献
24.
为了实现交通流在路网中的合理分配,可变信息板(VMS)通过发布动态交通信息来引导驾驶员选择最合理路径.通过构造基于陈述偏好调查(SP调查)的诱导信息下驾驶员路径选择行为的有序多分类Logit模型,分析各因素对驾驶员路径选择行为的影响.分析结果表明,年龄、出行距离、可选路径、VMS信任度、改变路径频率对驾驶员路径选择行为的影响较大.在驾驶员个人属性中,年龄对驾驶员的路径选择行为影响最大;在出行属性中,驾驶员对出行距离和可选路径最为敏感;在对VMS的认知和服从属性中,驾驶员对VMS信任度越高,按照VMS诱导信息改变出行路径的概率越大;改变路径频率越高的驾驶员,越易改变出行路径. 相似文献
25.
水润滑轴承是船舶轴系安全稳定运转的重要支撑部件,通过优化轴承结构以提升轴承性能是保证船舶安全航行的有效措施.采用PSO-BP神经网络建立水润滑轴承承载力和摩擦力预测模型,应用NSGA-Ⅱ以预测模型承载力最大和摩擦力最小为优化目标,优化预测模型的输入值使目标函数达到最优,得到轴承的Pareto解,通过TOPSIS方法选取Pareto解集的最优非劣解.结果表明:优化后的轴承承载力较原始设计值提高了 38.17%,摩擦力降低了 2.23%;预测模型的优化结果与将优化参数输入仿真模型计算得到的结果相比,误差小于7%. 相似文献
26.
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城市公共交通乘客出行成本的量化研究,对于科学合理地评价公共交通系统的社会效益意义重大,而出行时间价值是进行乘客出行成本估计的一个重要环节. 本文以北京市市区居民SP调查数据为依托,通过分析公共交通出行时间价值的影响因素,选取Logit模型为基础模型,引入“出行者收入”作为模型新增变量,并针对工作商务、社会娱乐两种出行目的在不同换乘情况下出行时间价值模型进行参数标定,建立了基于SP调查数据的改进型时间价值求解模型,并计算得到北京市公共交通出行者在不同出行目的和有无换乘情况下的换乘时间价值、候车时间价值以及运行时间价值. 研究发现,工作商务出行目的出行时间价值普遍高于社会娱乐的出行时间价值,出行者在不同出行目的和有无换乘情况下的候车时间价值,大于换乘时间价值以及运行时间价值,并且有换乘情况下的候车时间价值大于无换乘情况下的候车时间价值. 相似文献
27.
从社会网络的视角,提出了一种旅客个体偏好与关系偏好相结合的建模方法.首先,从旅客的历史出行记录中,构建基于共同出行关系的旅客社会网络;然后,构建旅客个体偏好模型和旅客关系偏好模型;最后,基于旅客偏好模型给旅客推荐座位.在民航领域的一个真实的数据集上进行了实验,证明本文提出的偏好模型能够有机地将旅客个体偏好与关系偏好结合起来,较好地描述旅客对航班座位的偏好. 相似文献
28.
为更好地反映不同决策者对电子收费系统(ETC)评价的偏好,从政府、运营者和付费者三个主要利益主体的角度对ETC系统的评价指标及评价方法进行了研究。根据评价指标体系筛选原则,确定了基于决策偏好的ETC系统评价指标体系;通过综合分析成本-效益法(CBA)和数据包络分析法(DEA)的各自特点,依据基于决策偏好所确定的评价指标,同时引入当前一些比较好的算法来优化CBA,DEA和AHP法,建立数学模型,从而确立了基于决策偏好的综合评价方法。该方法较为全面地对ETC系统社会经济影响进行评价,所建立的指标体系和方法能更直观、更可靠地反映出决策者的决策偏好。 相似文献
29.
优先发展公共交通,提高公交运行效率,不仅是缓解城市交通拥堵的有效措施,也是调整城市交通出行结构、改善城市人居环境、促进城市可持续发展的必然要求. 为制定科学、合理的公交票价政策,引导大众选择公共交通方式出行,以成都市为背景,采用问卷调查方法对不同出行者、不同票制、不同票价、不同换乘费用进行意愿调查,得到最大满意度票价;基于调查数据,进行供求曲线分析,提出以最适票价满意度作为供求平衡点;通过票价意愿曲线,进行客流、票价间敏感性分析,得到不同出行者票价梯度变化规律. 本研究可为公交分担率提升,合理票制票价的制定提供依据. 相似文献
30.
This paper analyses how people perceive the idea of carpooling and evaluate preferences while making a decision to join a carpool. Analysing data from a web-based stated preference survey in India reveals that cognitive attitudes play a significant role in evaluating the perceived advantages and disadvantages of carpooling whereas intentions to carpool are associated with perceived negative evaluations. A factor analysis identifies two latent attitudinal factors: a ‘time–convenience’ factor that discourages carpooling and a ‘private–public cost’ factor that encourages carpooling. The study analyses the influential attributes – extra travel time, walking time to reach meeting point, waiting time at pickup point and cost savings – as explanatory variables for the utility of carpooling. Cost savings prove to be the most significant attribute when combined with other attributes, followed by extra travel time. The study provides the implications to policy-makers of designing promotional tools to improve the propensity of carpooling among single occupant vehicle drivers. 相似文献