一类种群模型的混合有限元法分析

本文分别在时间连续和离散两种情况下,利用混合有限元方法对种群动力学中含有迁移的赤眼蜂--螟虫生态系统模型进行离散,论证了格式的可解性,导出了最优阶的L2模误差估计.     

发展省际道路超长客运的基本观点与相关理论

阐述了关于发展省际道路超长客运的基本观点;利用行业竞争理论、企业创新理论、组织权变理论与范围经济理论,解释了省际道路超长客运发生与发展的原因与过程;并基于文中的基本观点与相关理论,勾勒出省际道路超长客运管理的政策框架。     

A flexible model for the pricing of perishable assets

We present a flexible and versatile model which addresses the problem of assigning optimal prices to assets whose value becomes zero after a fixed expiry date. (Such assets include the important example of seats on airline flights.) Our model is broad in scope, in particular encompassing the ability to deal with arrivals of customers in groups. It is highly adaptable and can be adjusted to deal with a very extensive set of circumstances.Our approach to the problem is based on elementary and intuitively appealing ideas. We model the arrival of customers (or groups of customers) according to an inhomogeneous Poisson process. We incorporate into the model time dependent price sensitivity (which may also be described as “time dependent elasticity of demand”). In this setting the solution to the asset pricing problem is achieved by setting up coupled systems of differential equations which are readily amenable to numerical solution via (for instance) a vectorised Runge-Kutta procedure. An attractive feature of our approach is that it unifies the treatment of discrete and continuous prices for the assets.     

Benchmarking airports from a managerial perspective

Benchmarking airports is currently popular both in the academic literature and in practice but has proved rather problematic due to the heterogeneity inherent in any reasonably sized dataset. Most studies either treat the airport production technology as a black box, or separate the terminal and airside activities, assessing them individually. In this article we analyze airports as a single unit due to the direct complementarities, thus avoiding the artificial separation of inputs. Using data envelopment analysis (DEA), we open the black box in which a network describes the production process, thus demonstrating the sequential effects that separate final from intermediate outputs, including those under partial managerial control and those that are known to be non-discretionary. To further improve the benchmarking process, we identify appropriate peers for a case study of 43 European airports over 10 years, through a restricted reference mechanism according to pre-defined characteristics. Compared to basic DEA models, the results of the proposed structure provide more meaningful benchmarks with comparable peer units and target values that are potentially achievable in the medium term. By identifying each unit's individual reference set, unique outliers influence the performance measurement less severely than occurs under basic DEA. In addition, the formulations produce an implementation path that moves the airport towards the Pareto frontier gradually, taking into account the regulatory and business environment in which the unit is located.     

网络产业效率边界与中国铁路路局网效率边界的实证研究

以科斯为代表的新制度经济学为分析企业的形成、企业组织边界以及企业间关系提供了有力工具,20世纪70年代以来,网络经济概念及分析方法丰富了对企业与市场之间的组织形态--产业组织的分析.本文沿用新制度经济学分析思路,结合Mattew O.Jacson对网络基本概念的论述(Mattew O.Jacson,2002)[1],以实证分析的方法研究铁路运输产业的网络边界效率问题.     

昆明市公路客运枢纽换乘网络分析与评价

为了合理评估昆明市公路客运枢纽换乘网络的运营效率,在考虑城市综合客运枢纽功能及乘客换乘行为特征的基础上,系统分析了昆明公路客运枢纽换乘网络的要素与形态。通过乘客问卷调查采集实际数据,综合利用层次分析法与模糊综合评价法,建立城市综合客运枢纽换乘网络的评价指标体系与评价模型,并对昆明市五大客运站运营效率进行评估,结果表明五大客运枢纽换乘效率均处于＂一般＂水平,在此基础上提出相应的换乘网络优化对策。     

中心城市建设综合交通系统的经验、启示与对策——以伦敦、广州为例

通过分析伦敦的交通规划、建设、运营与管理措施,发现我国中心城市的严重交通拥堵主要源于落后的城市交通规划理念,大量引入多层高架公路进入市中心而忽视轨道交通建设,对公交优先存在认识上的误区和执行不力;城市公共交通工具营运各自为政,缺乏有效的协调与接驳;运营的低效率和管理不当,由此造成了典型的“大城市病”。根据后现代主义城市建设思想,结合当前中心城市公共交通体系建设的现状,提出了广州市综合交通体系建设的12项具体措施。     

北京市公交系统两种运行模式的比较研究

本文认为，与北京市目前的公交系统运行模式相比，双层“网络＋环形”的运行模式是一种新型高效、有可持续发展功能的公交系统运行模式。主要表现在：贯通型公交网络与环形的结合既能提高公交的机动性，又能提高其可迭性；单线路公交车安排和“枢纽一枢纽”型综合换乘方式都比旧的模式更能提高公交系统的运行效率。     

简述宋代漕运中押纲武臣与舟卒的营私获利活动

宋代漕运由低级武臣押纲,又有舟卒随船,是其重要特点。押纲武臣和舟卒等同纲船上其他人员营私舞弊,从中获利的不法行为频频发生。营私获利活动包括纲运时夹带私货贩易、在与一般交装中营私舞弊、直接侵盗官物、擅自靠港、违程住滞及南宋时期的＂随纲＂等。     

内蒙二连盆地赛汉塔拉凹陷构造特征及含油气远景

从赛汉塔拉凹陷的形成、演化及构造特征出发,探讨了凹陷构造发育的石油地质特征,阐述了凹陷油气赋存、断裂与油气的关系,指出:断裂活动的摩擦热以及岩断裂的火山喷发活动使该区地温梯度升高,有利于有机质转化为油气。通过以遥感资料、地球物理(重、磁、电)资料、地球化学资料三者相结合的遥感化探新方法综合分析凹陷的含油气性,评价了各含油气区块的含油气级别,进而明确了有利的含油气远景地区。