城市轨道交通运营初期票价方案的探讨

城市轨道到多种因素的制约。交通票价水平不仅影响运营企业的利润,也影响居民的福利水平。轨道交通票价的制定受本文根据轨道交通运营初期特点,市民、政府和轨道交通企业之间的关系,得出轨道交通初期票价公式。从重庆市轨道交通二号线南延伸段可行性研究中,得出基本上相同结论。     

对改装船舶价值评估方法的探讨

针对当前出现的改装船舶价值评估的实际,根据资产评估的一般理论和方法,提出了改装船价值评估的新方法--分段评估法和假想船型法.     

基于三次指数平滑法的建筑主材价格预测

工程建设项目一般周期较长,在招投标阶段如何预测和合理确定主要材料的价格对投标报价至关重要。随着施工的开展和主要材料价格的波动,合同价款的调整与幅度及风险分担,承发包双方往往存在不同意见或争执。为解决这一方面的问题,此文基于三次指数平滑法通过建立预测模型与分析,推导出计算公式。并以24mm热轧圆钢价格为样本对其中短期价格进行预测,预测结果表明,与实际价格的相对误差在3％左右,准确性较高,可以作为是否调整合同价款的依据。     

城市出租车拥有量对分担率影响分析

城市出租车的合理拥有量对促进城市公共交通发展、节省道路资源起到至关重要的作用。以出租车的空驶率、出租车在居民出行方式中的分担率、平均日运营车速、平均日运营时间和出租车价格等数据为参数,通过空驶率的计算方法,得出城市出租车拥有量的计算模型。最后通过北京市的实例分析,求得北京市出租车的合理拥有量,并进一步分析出租车的空驶率、分担率与拥有量之间的关系,推算出北京市出租车合理分担率范围。     

Optimal competitive freight network design as hierarchical variational inequalities programming problems

Freight networks are a case of systems that multiple participants are composing interrelations along the complete supply chain. Their interrelations correspond to alternative behavior, namely, cooperation, non-cooperation and competition, while they are large-scale spatially distributed systems combining multiple means of transportation and the infrastructure and equipment typically utilized for servicing demand, results to a complex system integration. In this paper, the case of the optimal design of freight networks is investigated, aiming to highlight the particularities emerging in this case of transportation facilities strategic and/or operational planning and the multiple game-theoretic and equilibrium problems that are structured in cascade and in hierarchies. The application that is investigated here focuses in the design of a significant ‘player’ of the freight supply chain, namely container terminals, while the proposed framework will aim on analyzing investment strategies built on integrated demand–supply models and the optimal network design format. The approach will build on the multilevel Mathematical Programming with Equilibrium Constraints (MPECs) formulation, but is further extended to cope with the properties introduced by the ‘designers’ (infrastructure authorities), shippers and carriers competition in all levels of MPECs. Since container terminals are typically competing each other, the nomenclature used here for formulating appropriate MPECs problems are based on hierarchies of Variational Inequalities (VI) problems, able to capture the alternative relationships emerging in realistic freight supply chains. The proposed formulations of the competitive network design case is addressed by a novel approach of co-evolutionary agents, which can be regarded as new in equilibrium estimation. Finally, the results are compared with alternative network design cases, namely the centralized cooperative and exchanging design. Under this analysis it is able to highlight the differences among alternative design cases, but moreover an estimation of the ‘price of anarchy’ in transportation systems design is offered, an element of both theoretical as well as practical relevance.     

Overview of missing physical commodity trade data and its imputation using data augmentation

The physical aspects of commodity trade are becoming increasingly important on a global scale for transportation planning, demand management for transportation facilities and services, energy use, and environmental concerns. Such aspects (for example, weight and volume) of commodities are vital for logistics industry to allow for medium-to-long term planning at the strategic level and identify commodity flow trends. However, incomplete physical commodity trade databases impede proper analysis of trade flow between various countries. The missing physical values could be due to many reasons such as, (1) non-compliance of reporter countries with the prescribed regulations by World Customs Organization (WCO) (2) confidentiality issues, (3) delays in processing of data, or (4) erroneous reporting. The traditional missing data imputation methods, such as the substitution by mean, substitution by linear interpolation/extrapolation using adjacent points, the substitution by regression, and the substitution by stochastic regression, have been proposed in the context of estimating physical aspects of commodity trade data. However, a major demerit of these single imputation methods is their failure to incorporate uncertainty associated with missing data. The use of computationally complex stochastic methods to improve the accuracy of imputed data has recently become possible with the advancement of computer technology. Therefore, this study proposes a sophisticated data augmentation algorithm in order to impute missing physical commodity trade data. The key advantage of the proposed approach lies in the fact that instead of using a point estimate as the imputed value, it simulates a distribution of missing data through multiple imputations to reflect uncertainty and to maintain variability in the data. This approach also provides the flexibility to include fundamental distributional property of the variables, such as physical quantity, monetary value, price elasticity of demand, price variation, and product differentiation, and their correlations to generate reasonable average estimates of statistical inferences. An overview and limitations of most commonly used data imputation approaches is presented, followed by the theoretical basis and imputation procedure of the proposed approach. Lastly, a case study is presented to demonstrate the merits of the proposed approach in comparison to traditional imputation methods.     

Differentiated congestion pricing of urban transportation networks with vehicle-tracking technologies

This paper explores a new type of congestion pricing that differentiates users with respect to their travel characteristics or attributes, and charges them different amounts of toll accordingly. The scheme can reduce the financial burden of travelers or lead to more substantial reduction of congestion. Given that the scheme requires tracking vehicles, an incentive program is designed to mitigate travelers’ privacy concerns and entice them to voluntarily disclose their location information.     

铁路客票计算机计价系统设计

主要针对全路客票系统的各种灵活的计价需求,论述铁路客票计算机计价系统的功能设计、算法设计和计算流程设计,结合客票系统4.0版本对计价系统的新需求,论述了计价系统设计的灵活性和适应性.     

The impact of advance purchase deadlines on airline consumers’ search and purchase behaviors

Airlines frequently use advance purchase ticket deadlines to segment consumers. Few empirical studies have investigated how individuals respond to advance purchase deadlines and price uncertainties induced by these deadlines. We model the number of searches (and purchases) for specific search and departure dates using an instrumental variable approach that corrects for price endogeneity. Results show that search and purchase behaviors vary by search day of week, days from departure, lowest offered fares, variation in lowest offered fares across competitors, and market distance. After controlling for the presence of web bots, we find that the number of consumer searches increases just prior to an advance purchase deadline. This increase can be explained by consumers switching their desired departure dates by one or two days to avoid higher fares that occur immediately after an advance purchase deadline has passed. This reallocation of demand has significant practical implications for the airline industry because the majority of revenue management and scheduling decision support systems currently do not incorporate these behaviors.     

Price of anarchy for non-atomic congestion games with stochastic demands

We generalize the notions of user equilibrium, system optimum and price of anarchy to non-atomic congestion games with stochastic demands. In this generalized model, we extend the two bounding methods from Roughgarden and Tardos (2004) and Correa et al. (2008) to bound the price of anarchy, and compare the upper bounds we have obtained. Our results show that the price of anarchy depends not only on the class of cost functions but also demand distributions and, to some extent, the network topology. The upper bounds are tight in some special cases, including the case of deterministic demands.