A dynamic model for marginal cost pricing of port infrastructures

ABSTRACT

A dynamic model for marginal cost pricing of port infrastructures links costs to system performance by combining a power-law function with time-dependent queueing analysis. Additionally, the model incorporates the marginal cost of capacity, including the effects of economies of scale. This allows the calculation of the marginal cost price under a dynamic framework. The model accounts for nonlinear behaviour of port demand, which is sensitive to price and service levels. The effects over time of cost and service levels on the port’s operational performance are quantified. The proposed model allows determining the optimal timing for capacity investment. The model is a starting point for the application of marginal cost pricing to ports. However, for practical application of such pricing method it is necessary to apply a system’s approach, as productivity and costs must be assessed at the terminal’s component level. This should allow the derivation of a marginal cost function at the terminal’s component level.     

公路施工项目成本管理实证分析

结合实际工程，在项目成本管理过程中，综合运用目标成本法和作业成本法，使项目成本分析做到全面、透彻，取得了良好的效果。     

公路工程造价投资控制现状与对策

分析了现阶段公路工程建设造价投资控制现状及存在的问题,结合国外先进投资理念,针对决策阶段、建设阶段、运营阶段造价控制提出对策。根据国家交通运输＂十二五＂发展规划,提出了全寿命成本理念及交通建设节约资源、有效利用土地资源的新理念。     

浅探港口企业成本精细化管理

为降低港口企业成本,提高效益,对港口企业实施成本精细化管理.从树立成本精细化管理理念、建立成本控制工作机制、强化管理、坚持创新等4个方面阐述具体做法.     

Marine Protected Area Costs as “Beneficial” Fisheries Subsidies: A Global Evaluation

Marine protected areas (MPAs) are now generally accepted as important tools in the protection of coastal biodiversity. It is also likely that they play a positive role in enhancing fisheries. Yet currently, less than 1% of the global oceans are protected, although international agreements have targets ranging from 10–30% coverage. Despite its minuscule size, we consider the current MPA “network” to be beneficial to fisheries, and its running or maintenance cost, therefore, to be a positive contribution to the sustainability of fisheries, or a “beneficial” subsidy (“harmful” subsidies enhance fishing capacity and effort). A method was derived from data in Balmford et al. (PNAS, 101: 9694–9697) to estimate the annual cost of maintaining MPAs as a function of their size, and of the degree of development of the country in question. We provide national costs of the 53 countries that jointly contribute 95% of global fisheries catch and, assuming that this type of subsidy, in a given country, cannot exceed 15% of the ex-vessel value of its fisheries catches, estimated a global MPA subsidy to fisheries of 870 million US$. Given that total subsidies to fisheries currently range from 30–34 billion US$ annually (without MPA costs), this amounts to only 2.5–2.8% of total subsidies to fisheries being devoted explicitly to the maintenance of the biodiversity that sustains them.     

A time‐staged multi‐objective network‐design model

A multi‐objective, time‐staged network‐design problem is formulated. Through transformation, the problem is decomposed into a set of single‐period, single‐objective problems. Lexicographic ordering is instrumental in effecting this transformation; it also allows a backward‐recursion algorithm to be applied using strong pruning criteria. Furthermore, monotonicity properties enable us to solve the problem using the familiar tree‐search algorithms. The solution method has several desirable properties — as shown by an example and a case study of Tripoli Province, Libya. First, the algorithm ensures continuity of project implementation over the multi time‐periods and provides optimality in later computational stages irrespective of the decision at an interim stage. Second, the algorithm tends to provide accessibility to unconnected regions in the study area at low user‐cost without employing weights to the two objective functions of accessibility and user‐cost efficiency. Such a property is deemed advantageous for suggesting transportation investments based purely on purchasing the greatest benefit for each dollar, with political neutrality strictly maintained.     

南宁市交通管理和控制系统优化方案分析工具的建立

交通仿真是采用计算机数字模型来反映复杂的交通现象,对交通运动随时间和空间的变化进行跟踪描述和分析。不同精度的交通仿真模型有不同的优缺点,要客观的评估城市的交通管理和控制系统优化措施,应将不同精度的模型配合,作为分析工具。本次研究采用中宏观的SATURN作为主导模型,对南宁市的宏观的交通进行整体分析,以及对不同交通改善方案进行评估。选用TSIS、SYNCHRO交通仿真软件作为辅助的交通分析工具,对局部地区的交通及信号配时作较为具体的分析,以利于本研究针对各种建议方案进行客观性的整合分析与应用。     

基于综合性能的沥青混合料组成结构优化

为了基于性能进行沥青混合料组成设计,对沥青混合料的综合性能优化进行了研究。根据胶浆理论,将沥青混合料的性能分为分散相主导型和分散介质主导型两类。选择4.75 mm筛孔通过率、0.075 mm筛孔通过率(矿粉用量)、粉胶比、空隙率作为沥青混合料性能优化决策参数。采用BP神经网络和遗传算法相结合的方法,对沥青混合料组成结构参数进行了优化。研究结果表明,随着疲劳性能的权重减小和高温稳定性权重的增大,4.75 mm筛孔通过率应逐渐减小;无论对疲劳性能还是高温稳定性,都需要5%~7%的矿粉用量和足够的沥青用量;粉胶比越小,沥青用量越大,疲劳性能越好;3%~4.5%空隙率的沥青混合料综合性能较好。     

高速公路路段通行能力模糊综合评判

针对高速公路路段通行能力影响因素的不确定性和模糊性,利用层次分析法确定各影响因素的权重,运用模糊数学基本原理建立模糊综合评判模型,对某高速公路路段通行能力进行模糊综合评价,说明其实用性,为高速公路路段通行能力的评判提供一种有效的方法.     

城市河道综合整治研究

随着上海城市化进程的加快,人口陆续向城区集中,城市发展对河道的水环境、水景观等综合功能提出了更高的要求。上海在近10年的城市河道综合整治中,借鉴国内外河道综合整治成功的做法,积极地探索整治经验,以点带面,走出了一条城市河道综合整治的成功道路。该文对城市河道综合整治的对策措施进行了研究,对城市河道综合整治有一定的借鉴作用。