铁路改革中公益性问题的解决途径

铁路公益性问题的解决是铁路改革的前提。本文从分析铁路公益性问题的经济学特征入手,探讨了公益性问题的成因,研究了存在的问题及约束条件,提出了解决途径。     

城市管网存在问题引发的思考

分析了城市管网存在的问题,从前期规划、施工建设、后期管理等方面,阐述了引发问题的种种原因,并系统地提出了问题的解决方案.     

浅析盾构隧道模型试验的现状与发展

模型试验是盾构隧道相关研究工作中常用的研究手段。文章对目前盾构隧道模型试验所涉及到的问题进行了系统总结分析,将其归结为管片结构的受力问题、隧道结构本身的分析模型问题、结构与围岩的相互作用问题、开挖面稳定问题、结构与邻近结构物的相互作用问题、隧道施工扰动与控制问题,以及其他问题等。通过典型模型试验实例,对每类问题进行了分析阐述,系统归纳了模型试验在盾构隧道相关研究工作中的进展和成果。针对盾构隧道模型试验经常涉及到的诸如结构模型、模型土、模型箱等材料的选择,加载方案的设计,以及试验方案的综合设计等问题进行了阐述分析,并针对性地提出了意见和建议。     

关于城市轨道交通发展的反思和建议

本文就城市轨道交通在加快发展过程中暴露出来的客流预测问题、线路长度问题、线路延伸问题、车站的建设规模问题、不合理工期问题、线路的敷设方式问题、技术装备的标准化问题进行了剖析,对我国城市轨道交通的进一步发展和建设给出了几点建议。     

遗传算法在精益物流配送线路优化中的应用

精益物流配送活动中出现的一类散户配送问题是典型的组合优化问题,利用传统的优化方法计算复杂、难以求得全局最优解,遗传算法在求解这类问题中表现出了强劲的优势.利用遗传算法对这类特殊问题进行了研究分析,针对具体的配送问题进行了仿真试验,在实验的基础上探索了交叉算子、变异算子的优化设计,实验结果证明了遗传算法在解决这类问题上的可行性和有效性.     

工程建设领域突出问题治理探讨

文章阐述了交通运输系统工程建设领域突出问题的现状和主要表现形式,分析了问题产生的原因,并从教育、制度、监管和惩处等方面提出了治理工程建设领域突出问题的思路与对策。     

公路路基常见质量问题及应对措施的探讨

重点探讨公路路基的几种常见质量问题,并分析了各种路基质量问题的产生机理,提出了对公路路基常见质量问题的防治措施。     

高速公路建设项目资金管理问题探讨

高速公路建设项目普遍具有投资规模大、建设周期长、涉及利益群体多的特点,在建设过程中,资金管理易出现问题。文章结合当前高速公路建设项目的实际情况,阐述了其实施过程中资金管理存在的问题,分析了问题产生的原因,并提出了防范和控制资金管理问题的相关措施。     

技术创新问题探讨

分析了影响技术创新发展的主要问题,提出了解决这些问题的具体措施.     

筑养路机械维修中技术问题分析

通过对筑养路机械维修工作中普遍存在的技术问题分析,提出了问题的成因、导致的后果,并提出了解决问题的方法和避免问题的注意事项.     

Transport problems as perceived by inner city firms

The role of transport policy in assisting inner city firms is still unclear. This paper raises several important policy questions and reviews the findings of past research, which suggest that transport problems are a major irritant to inner city firms but are unlikely to cause them to leave the area, and that the ability of transport improvements to attract new firms is uncertain.It describes and presents the results of a recent study designed to determine the effect of transport problems on manufacturing and service industries, whether such problems are more serious in the inner city, and which solutions would be most appropriate. The study involved a series of detailed case studies of inner and outer city firms in Leeds and London. It identified as the most serious problems, congestion, public-transport problems, parking shortages and on-site delays for commercial vehicles. Similar problems arose in all areas, but were more severe in inner than in outer areas, and in London than in Leeds.The most common effect was lost time, but reduced efficiency, lost business, staff dissatisfaction and recruitment problems also occurred. Management had difficulty costing the effects of such problems, and often overlooked those incurred by others. The problems were, for the most part, local or site-specific, and are likely to be amenable to low-cost solutions. However, congestion and parking problems in inner London appear to merit area-wide treatment.A series of recommendations is provided for policy-makers.Further details of the study reported here are contained in a series of working papers which are available from the Institute for Transport Studies, University of Leeds.     

Ranking the substantive problems in the Dutch Cost–Benefit Analysis practice

This paper investigates the perceptions of key participants in the Dutch Cost–Benefit Analysis (CBA) practice regarding substantive problems when appraising spatial-infrastructure projects with CBA. Two research methods were applied. Firstly, 86 key participants in the Dutch CBA practice were interviewed in-depth in order to obtain an overview and a ranking of perceived substantive problems with CBA in the Netherlands. Secondly, the people interviewed were also asked to fill in a written questionnaire in which they were asked to rank the substantive problems once again, in order to improve the validity of the ranking; 74 of the participants completed this questionnaire. The most important conclusions of this paper are, firstly, that key participants in the Dutch CBA practice consider ‘problems with the estimation of the non-monetized project effects’ as the most important substantive problem cluster and ‘problems with monetizing project effects’ as the second most important substantive problem cluster. Secondly, key participants in the Dutch CBA practice consider the ‘problem analysis’ in a CBA to be a very important substantive problem. Thirdly, there is, in a broad sense, consensus among the different groups in the Dutch CBA practice concerning their perception of the seriousness of problem clusters and the way they rank the problem clusters. Fourthly, a large part of the substantive problems mentioned by the key participants in the Dutch CBA practice are non-specific CBA problems.     

Dynamic routing-and-inventory problems: a review

The paper presents a review of the available literature on a class of problems denoted as dynamic routing-and-inventory (DRAl) problems. They are characterized by the simultaneous relevance of routing and of inventory issues in a dynamic environment, within the framework of distribution logistics. A classification scheme is first proposed for these problems. Then the results obtained in this area are summarized. Finally, the papers available in the literature are clustered and discussed according to the proposed scheme.     

Optimal shipment decisions for an airfreight forwarder: Formulation and solution methods

We study the freight forwarder’s shipment planning problem in an airfreight forwarding network where a set of cargo shipments have to be transported to given destinations. We provide mixed integer programming formulations that use piecewise-linear cargo rates and account for volume and weight constraints, flight departure/arrival times, as well as shipment-ready times.After exploring the solution of such models using CPLEX, we devise two solution methodologies to handle large problem sizes. The first is based on Lagrangian relaxation, where the problems decompose into a set of knapsack problems and a set of network flow problems. The second is a local branching heuristic that combines branching ideas and local search. The two approaches show promising results in providing good quality heuristic solutions within reasonable computational times, for difficult and large shipment consolidation problems.     

Application of genetic algorithm for scheduling and schedule coordination problems

The problems on scheduling and schedule co‐ordination usually have conflicting objectives related to user's cost and operator's cost. Users want to spend less time to wait, transfer and travel by public buses. Operators are interested in profit making by lesser vehicle operating cost and having a minimum number of buses. As far as level of service is concerned users are interested in lesser crowing while operators are concerned with maximizing profit and thus to have higher load factors. In schedule co‐ordination problems transfer time plays an important role. Users are interested in coordinating services with in acceptable waiting time whereas operators prefer to have lesser services and want to meet higher demands, which invariably increases waiting time. These problems have multiple conflicting objectives and constraints. It is difficult to determine optimum solution for such problems with the help of conventional approaches. It is found that Genetic Algorithm performs well for such multi objective problems.     

Rail freight transportation: A review of recent optimization models for train routing and empty car distribution

This paper describes two types of rail transportation problems in detail. These are train routing and makeup, and empty car distribution problems. Some of the recent optimization models which address these problems are reviewed and the areas for potential improvements in rail transportation literature are identified. The type of interactions which exist between routing, makeup, and empty car distribution decisions are highlighted and potential areas for future research are identified.     

南宁市农村道路交通安全问题及对策分析

文章结合南宁市农村地区交通安全现状,分析了当前农村道路交通安全工作中存在的主要问题,提出了解决问题的对策与思路。     

合资铁路重组背景下省级铁路平台可持续发展对策

在铁路行业高度垄断,铁路运营普遍效益欠佳和地方政府财力有限的现实环境下,特别是国铁集团近年来大力推行“一省一公司”合资铁路重组整合的改革,对省级铁路平台的发展带来了新的巨大的问题挑战,本文结合当前在全国大力推行的合资铁路重组改革的背景,分析了省级铁路平台在改革中将面临的重大问题,包括既有投融资能力难以支撑大规模规划项目建设、已建铁路运营大规模亏损、铁路行业建设运营高度垄断严重以及铁路土地综合开发进展迟缓等一系列问题,并针对以上问题提出相关的对策建议。     

高速公路科技档案管理存在的主要问题和对策

文章基于高速公路科技档案管理的现状和发展需求,分析了高速公路科技档案管理存在的主要问题,提出了解决问题的对策,并对创新高速公路科技档案管理技术的发展研究方向进行了展望。     

我国高速公路财务管理的对策研究

高速公路的快速发展,为社会带来了巨大的经济效益和社会效益,同时也给高管公路的财务管理提出了新的课题。从高速公路财务管理的特点、现阶段存在的问题以及解决问题的对策进行论述。