Deconstructing delay: A non-parametric approach to analyzing delay changes in single server queuing systems

This paper introduces an empirically driven, non-parametric method to isolate and estimate the effects that changes in demand and changes in throughput have on delay – in particular, arrival and departure flight delay at airport runways. Classic queuing concepts were used to develop a method by which an intermediate, or counterfactual, queuing scenario could be constructed, to isolate the delay effects due to shifts in demand and throughput. This method includes the development of a stochastic throughput function that is based entirely on data and has three key features. Firstly, the function relies on non-parametric, empirically-based probability distributions of throughput counts. Secondly, facility capacity needs not be explicitly defined, as it is implicitly included in the probability distributions of throughput. Thirdly, the throughput performance function preserves the effect of factors that cause capacity (and, therefore, throughput) to fluctuate over a given period. Temporal sequences of high, moderate, and low capacity are maintained between the observed and counterfactual scenarios. The method was applied to a case study of the three major New York area airports of LaGuardia (LGA), Newark Liberty (EWR), and John F. Kennedy (JFK), using operational data extracted from the Federal Aviation Administration’s (FAA’s) Aviation System Performance Metrics (ASPM) database. The focus was on the peak summer travel seasons of 2006 and 2007, as these airports experienced record levels of delay in 2007. The results indicate that decreases in both demand and throughput were experienced at LGA and EWR, although the decreases in throughput had more significant effects on operational delays as they increased overall at these airports. At JFK, the increase in departure throughput was not sufficient to offset the increase in departure demands. For arrivals, demand increased and throughput decreased. These trends caused a significant growth in delay at JFK between 2006 and 2007.     

一条海底输油管道的定量风险评估其检测标准设计(英文)

该报告描述一条预设海底管道的基于定量风险分析(QRA)的泄漏检测标准(LDc)设计问题.定量风险分析的结果会反映出统计泄漏检测方法是否必要.如果必要,恰当的泄漏检测标准必须建立.在分析中,著名的英国PARLoc 2001数据库将会用来估算管道实效概率.而来自MMS的POSVCM模型则用来做泄漏模拟计算.定量风险分析的结果说明,统计方法的泄露检测系统能打幅度地减少泄漏检测所需时间,从而减轻泄露的事故后果.根据QRA的分析结果,以及许多泄漏检测系统买主的建议,合理的西漏检测标准被设计出来.一旦泄漏事故产生,它可以帮助紧急事故相应组(ERT.)快速检测,定位以及采取方法减轻泄漏.     

PDMS元件库在自升式钻井船项目的应用

Vantage PDMS为一体化多专业集成布置设计数据库平台,可以进行工程设计最难点--管道详细设计,并可以进行设备、结构、暖通、电缆桥架、支吊架各专业详细设计,同时可以实现各专业间充分关联联动.该文主要研究VantagePDMS软件数据库在自升式钻进船项目配管方面的应用,其中主要包括管道元件库、管道等级库、螺栓库等方面的内容.文章对建库的主要方法进行阐述,对建库过程出现的问题进行研究,总结出Vlantage PDMS软件数据库在工程设计中的注意事项,并探讨了部分问题的解决方法.     

基于KBE技术的复杂零件CAM系统研究

针对复杂零件数控编程工作目前存在的问题,将知识工程（Knowledge Based Engineering,KBE）技术引入复杂零件的数控编程中,系统地阐述了复杂零件广义知识库的内涵及构造原理,通过知识的获取、学习及推理,形成复杂零件的加工工艺决策,并在UG平台上运用二次开发技术,建立了复杂零件的智能数控编程导航模板,构造出基于广义知识库的复杂零件智能数控编程体系．开发的CAM系统经初步应用,证明可行,从而使复杂零件的数控编程过程简单化、高效化、智能化．     

水面舰艇编队成员对潜攻击命中概率数据库研究

基于潜艇对水面舰艇编队威胁判断的需要,针对命中概率数据实时取得较为困难的问题,采用较成熟的DBMS平台,分数据库建立必要性和可行性分析、数据库组成和数据库建立流程三个方面,对水面舰艇编队成员对潜攻击命中概率数据库的建立进行探讨。     

基于CRISP-DM的交通大数据分析方法及实践——以重庆市手机信令数据和RFID数据为例

随着交通大数据研究及应用日益广泛,其中存在的问题也越来越明显。很多分析结论存在概念模糊、数据质量不确定、分析方法不清晰等问题,导致分析结果经不起推敲,也缺乏可比性。究其主要原因是未能形成科学的大数据分析方法和统一的分析标准。提出基于CRISP-DM的交通大数据分析方法,包括目标要求、数据理解、数据准备、数据建模、模型验证、工程化应用(部署)6个阶段。结合重庆市交通大数据平台建设实践,以手机信令数据和车辆RFID数据为例,详细阐述数据理解、数据建模和模型验证三个重要步骤的具体做法,探索如何实现交通大数据分析的标准化、指标化和透明化。     

基于高速公路收费数据库的断面交通量计算方法

根据我国高速公路绝大部分为封闭式收费公路的特性,提出基于高速公路收费站通行记录数据库的OD矩阵整理算法以及断面交通量的计算方法,并结合实例对此算法进行分析验证,对高速公路收费管理具有很高的应用价值。     

A connected-vehicle-based dynamic control model for managing the bus bunching problem with capacity constraints

This paper describes a connected-vehicle-based system architecture which can provide more precise and comprehensive information on bus movements and passenger status. Then a dynamic control method is proposed using connected vehicle data. Traditionally, the bus bunching problem has been formulated into one of two types of optimization problem. The first uses total passenger time cost as the objective function and capacity, safe headway, and other factors as constraints. Due to the large number of scenarios considered, this type of framework is inefficient for real-time implementation. The other type uses headway adherence as the objective and applies a feedback control framework to minimize headway variations. Due to the simplicity in the formulation and solution algorithms, the headway-based models are more suitable for real-time transit operations. However, the headway-based feedback control framework proposed in the literature still assumes homogeneous conditions at all bus stations, and does not consider restricting passenger loads within the capacity constraints. In this paper, a dynamic control framework is proposed to improve not only headway adherence but also maintain the stability of passenger load within bus capacity in both homogenous and heterogeneous situations at bus stations. The study provides the stability conditions for optimal control with heterogeneous bus conditions and derives optimal control strategies to minimize passenger transit cost while maintaining vehicle loading within capacity constraints. The proposed model is validated with a numerical analysis and case study based on field data collected in Chengdu, China. The results show that the proposed model performs well on high-demand bus routes.     

营改增统计关系管理系统在云南交通行业中的研究与应用

系统基于三层体系结构设计,采用分布式数据库技术实现海量数据的存储。主要包括:用户权限管理子系统、组织关系管理子系统、系统基础设置子系统、数据采集子系统、管理基础设施子系统、数据采集子系统、数据归档审核子系统、用户注册子系统、评估体系及决策分析子系统等,目前系统已经在交通行业推广应用。     

整车性能在整车开发中的应用管理研究

基于某纯电动车的开发案例,通过对整车性能分类、性能开发关键路径、目标设定及达成管理等方面进行研究。同时为了更好的在整车开发过程中对整车性能进行管控,结合公司实际情况对性能集成的工作进行了明确定义,实践表明该管理策略可执行度高,且能顺利推动性能集成工作开展。研究为后续整车性能在开发中的应用管理提供参考。