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This paper examines the optimal containership schedule with transit-time-sensitive demand that is assumed to be a decreasing continuous function of transit time. A mixed-integer nonlinear non-convex optimization model is first formulated to maximize the total profit of a ship route. In view of the problem structure, a branch-and-bound based holistic solution method is developed. It is rigorously demonstrated that this solution method can obtain an ε-optimal solution in a finite number of iterations for general forms of transit-time-sensitive demand. Computational results based on a trans-Pacific liner ship route demonstrate the applicability and efficiency of the solution method. 相似文献
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岳鹏 《兰州交通大学学报》2014,(2):122-127
我国大学英语新一轮教学改革特别强调应注重学思结合,其根本目标就是要提高学生的思辨能力、创新能力。作者将网络合作学习策略探索性的应用在大学英语课堂教学活动中,通过实验教学、问卷调查及访谈等方式开展实证研究。通过实验数据分析,发现网络合作学习策略在教学中的应用的确对提高学生的思辨能力水平起到了积极推动的作用。 相似文献
55.
Based on train scheduling, this paper puts forward a multi-objective optimization model for train routing on high-speed railway network, which can offer an important reference for train plan to provide a better service. The model does not only consider the average travel time of trains, but also take the energy consumption and the user satisfaction into account. Based on this model, an improved GA is designed to solve the train routing problem. The simulation results demonstrate that the accurate algorithm is suitable for a small-scale network, while the improved genetic algorithm based on train control (GATC) applies to a large-scale network. Finally, a sensitivity analysis of the parameters is performed to obtain the ideal parameters; a perturbation analysis shows that the proposed method can quickly handle the train disturbance. 相似文献
56.
Isam Kaysi Hani Mahmassani Sati Arnaout Lina Kattan 《Transportation Research Part D: Transport and Environment》2000,5(6)
The serious public health effects of lead are widely recognized, and many countries of the world have taken steps to completely eliminate it from automotive fuels. This study reviews the international experience with phasing out leaded gasoline; considerations affecting adoption of unleaded fuel are identified, and difficulties underlying change are synthesized. Factors related to technology, supply availability, distribution channels, economics, and social equity are underlined. International experience is distilled into a set of desirable characteristics of policies for phasing out leaded fuel. Such desirable properties include robustness vis-à-vis enforcement and compliance, the existence of a few “control points”, flexibility with respect to future vehicle and fuel technologies, cost-neutrality, and fairness in terms of incidence on socio-economic groups. The case of Lebanon is considered in structuring a practical strategy for phasing out leaded fuel. Positive and negative factors likely to affect the success of lead phaseout strategies in Lebanon are identified. Consideration of these factors along with the desirable attributes of successful policies has led to the development of a recommended plan for leaded fuel phaseout. 相似文献
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企业物流管理中的战略规划 总被引:2,自引:0,他引:2
本着重从企业物流管理战略目标的设定、竞争战略的定位、物流系统发展战略的制定等方面讨论了企业物流管理中的战略规划问题,研究了企业如何制定出合适的物流战略规划,为企业带来真正的竞争优势。 相似文献
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进入新世纪,美国国内关于批判和修改现行军事战略的呼声甚为强烈.本文就美国现行军事战略的基本内容,美国国内关于军事战略争论的几个重要问题,以及新一届美国政府可能对军事战略做出的重大调整作了简要评析. 相似文献
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科学合理的微观交通流仿真模型是研究交通控制手段有效性的关键.本文结合一种考虑驾驶员视野内前后多车影响的跟驰策略,建立了连续型元胞自动机交通流模型.仿真实验表明,仿真数据与实测数据有较好的拟合性,仿真得到的 K-Q、K-V和 Q-V图能较好地反映实际道路交通流的失稳现象,所建立的模型具有适应不同场景的兼容性与灵活性,能够作为研究我国实际道路交通流问题的仿真工具. 相似文献