对铁路站场到发线曲线地段建筑限界加宽方法的探讨

现行规范对铁路站场到发线曲线地段建筑限界加宽方法有相关规定,实际应用中因动车组列车与普速列车基本参数的差异导致曲线地段建筑限界加宽与实际有差距。通过阐述铁路站场设计现行曲线限界加宽的相关规范规定,结合铁路总公司对客站曲线地段建筑限界加宽的最新要求,分析铁路到发线曲线地段建筑限界加宽的理论计算公式,指出现行曲线地段建筑限界加宽规定存在的主要问题,从而修正现行曲线地段建筑限界加宽的相关规定,以满足实际曲线地段建筑限界加宽要求,杜绝运营中发生车体剐蹭建筑物的事故。     

城市道路瓶颈交通调节策略研究

根据道路瓶颈的形成机理及主要特征,提出瓶颈交通汇入量控制策略、诱导分流策略及需求调节策略,并构建相应的调节流程,对解决城市瓶颈交通问题有一定的指导作用.     

Optimal pricing for build-to-order supply chain design under price-dependent stochastic demand

Build to order (BTO) is a supply chain disruption mitigation strategy. Whereas cost minimization is an operational objective, the goal of the BTO manufacturer is to maximize its profit by using pricing as its competitive decision-making strategy. In this paper, we study a BTO manufacturer who simultaneously determines its product prices and designs its supply chain network to maximize its expected profit under price-dependent stochastic demand. We propose an L-shaped decomposition with complete enumeration to solve for optimality and show that the expanded master problem remains convex programming, although the optimality cuts are quadratic inequalities. The computational results demonstrate that stocking up on differentiated components and allocating modules appropriately to meet realized demand is a resilient policy that sustains variations in demand. Furthermore, the pricing decision balances the expected revenue and expected operating cost with an increase in expected profit. The integration of pricing and operational planning results in a higher expected profit than by individual decisions. We also demonstrate that cost minimization may not provide the same level of profit if the manufacturer overestimates or underestimates its most profitable demand.     

Review and Outlook of Roundabout Capacity

Capacity is an important part of the operation efficiency at roundabouts. Through analyzing existing capacity models of roundabout, this paper focuses on the problem research principles and methods such as empirical regression model, gap acceptance model and model based on simulation software. The key technologies of modeling are also analyzed. Then the general approaches of modeling roundabout capacity are proposed, combined with some problems easily overlooked in previous study. Determining the interaction mechanism among each traffic flow and considering the significant impact factors, the capacity model is established on the whole. Finally, combing with the control objectives of roundabouts, an outlook is proposed for future studies on roundabout capacity.     

关联理论视角下的语篇连贯研究

以Sperber＆amp;Wilson提出的关联理论为研究视角，通过对关联理论提出的关联原则、认知语境观、明示－推理交际观等主要观点的分析和理解，结合具体的例句，进一步探索该理论对命题内容连贯和语境效果连贯两大语篇连贯类型的解释力，并得出结论：正确判断某个语篇是否连贯不在于形式上的衔接，主要体现在“言而有其义”，语义上的关联才是贯穿整个语篇的主线。     

Brake light cellular automaton model with advanced randomization for traffic breakdown

Traffic breakdown is one of the most important empirical phenomena in traffic flow theory. Unfortunately, it cannot be simulated by many traffic flow models. In order to clarify its mechanism, the new brake light cellular automaton model has been proposed. Comparing with previous brake light models, three different aspects have been considered: (i) drivers tend to take large decelerations if the time gap is smaller than the safe time gap and the leading vehicle’s brake light is on; (ii) the brake light rule is set according to the reality; (iii) the randomization rule is put forward before the acceleration rule to weaken the impact of brake light on driving behaviors. Analyses show that the new model can explain the mechanism of traffic breakdown and the failures of other brake light models. Simulations confirm that all empirical features of traffic breakdown are successfully reproduced. At last, brake light models are calibrated and validated by the I-80 empirical data provided by NGSIM. Results show that the performance of the new model is the best and models in the three-phase theory are not necessarily better than models in the fundamental diagram approach and vice versa, at least for the brake light models.     

基于IDM的需求扰动供应链协调契约研究

针对具有需求扰动风险的供应链协调问题，基于利益驱动机制，设计出一种新的保险契约模式，建立相应的供应链模型并求解分析。结果表明：均匀分布市场需求下赔偿上限应足够大，且契约参数满足相关条件时供应链可以达到完美协调。最后通过数值分析了赔偿参数对订货量和保费的影响。     

A review of the impact of parking policy measures on travel demand

This paper reviews the empirical evidence relating to the impact of parking policy measures on the demand for parking and for travel. Disaggregate modal choice models, disaggregate parking location models and site‐specific studies of parking behaviour are examined. With regard to modal choice models, it is concluded that few studies deal adequately with parking factors, but that there is some support for the view that parking policy measures are a relatively important influence on modal choice. When parking location models are examined parking policy variables are shown to have a substantial impact on choice of parking location. With regard to site‐specific studies, the paper concludes that there is a great variation in the parking price elasticities quoted, which reflects partly the methodological problems associated with such studies. Suggestions to improve model specification are made.     

喀什经济开发区综合交通规划中交通需求预测

喀什地区位于中国的西大门，与5个国家接壤，有6个国家一类口岸对外开放，区域优势明显．对喀什经济开发区交通需求的科学研究是促进该研究区域交通运输事业规范而高速发展的关键．本文采取时间序列预测法、弹性系数法、综合评价法等方法，系统全面地对该区域交通需求预测进行了分析，为该区域综合交通规划与建设奠定了基础．     

考虑车道荷载差异的多车道桥梁横向折减系数

为考虑车道荷载差异对多车道桥梁横向折减系数的影响，提出横向折减系数的多系数表达模式，并改进基于独立重复试验的相遇车道荷载方法以进行系数校核。首先，引入反映车道荷载差异性的车道修正系数和体现多车道荷载相遇概率的车道组合系数，形成横向折减系数的多系数表达模式。其次，改进目前常用的基于独立重复试验的相遇车道荷载方法，将车道交通流量及荷载分布的差异性涵盖进来。随后，参数化研究横向折减系数的关键影响参量，包括货车通过控制断面的平均时间、荷载重现期、车道交通量和车道荷载分布等。最后，基于某高速公路实测动态称重数据，给出采用该方法校核横向折减系数的详细过程，并与传统方法及JTG D60-2015规范方法所得结果进行对比。研究表明：所提出的改进相遇车道荷载方法，摈弃了传统方法中车重正态分布、车道荷载同分布、最大观测车重与均值3.5倍偏差关系等备受质疑的假设，是更一般性的解答。参数化分析表明：货车通过控制断面的平均时间和荷载重现期对结果影响很小，货车荷载模型及其在车道间差异性则影响很显著，说明对车道荷载分布规律进行准确建模的重要性。实测车道货车荷载数据统计发现：货车的交通量和荷载分布在车道之间具有明显的差异，传统方法和规范方法给出的横向折减系数均高估了实际情况，最大达19%，可能造成设计与管养资源的浪费；而基于该方法校核的横向折减系数，更能深入揭示各车道荷载的贡献规律，准确反映不同车道组合作用下的荷载横向折减规律，具有显著的工程应用价值。