放宽条件定点集结模式下编组站车辆 集结排队系统分析

集结模式决定了货车集结过程的结束条件，定点集结是一种高效率的集结方式，有利于提高运输质量.针对放宽条件定点集结模式下编组站车辆集结过程，建立离散时间批到达批服务排队模型，利用嵌入式马尔可夫链方法求得离去时刻瞬时系统集结车辆队长分布，并求得任意时刻车辆集结队长分布，在此基础上分别分析了最小编成辆数，车组大小分布，车流到达强度，服务时间间隔分布对车辆平均集结队长，集结延误时间，效率，一昼夜发送车流量等系统指标的影响.分析结果表明，各因素对车辆集结排队系统影响明显.因此，利用本文提出的模型能为编组站的精细化管理和车流组织优化提供决策参考.     

An optimal data-splitting algorithm for aircraft scheduling on a single runway to maximize throughput

In this research, we present a data-splitting algorithm to optimally solve the aircraft sequencing problem (ASP) on a single runway under both segregated and mixed-mode of operation. This problem is formulated as a 0–1 mixed-integer program (MIP), taking into account several realistic constraints, including safety separation standards, wide time-windows, and constrained position shifting, with the objective of maximizing the total throughput. Varied scenarios of large scale realistic instances of this problem, which is NP-hard in general, are computationally difficult to solve with the direct use of commercial solver as well as existing state-of-the-art dynamic programming method. The design of the algorithm is based on a recently introduced data-splitting algorithm which uses the divide-and-conquer paradigm, wherein the given set of flights is divided into several disjoint subsets, each of which is optimized using 0–1 MIP while ensuring the optimality of the entire set. Computational results show that the difficult instances can be solved in real-time and the solution is efficient in comparison to the commercial solver and dynamic programming, using both sequential, as well as parallel, implementation of this pleasingly parallel algorithm.     

BIM技术在清华珠三角公建项目施工中的应用研究

随着科技的进步及项目管理水平的提高,BIM技术应运而生。本文以清华珠三角研究院粤港澳大湾区创新基地项目为依托,从应用目标、应用前准备工作、前期策划管理、技术管理、质量安全管理、物资设备管理、进度管理、经济成本管理等方面开展BIM技术在公建项目施工中的应用研究,结果表明:使用BIM技术,使项目管理走向精细化、全面化、高效化,并提高质量标准,增加安全保障,减少项目成本,提高项目利润率;同时与AI技术相结合,使BIM技术更加具有简便性,产出更大效益。     

缓波型非粘接柔性立管的干涉敏感性

针对非粘接柔性立管在波浪和海流作用下易发生立管干涉的问题,以我国南海某油田输油立管和相邻锚链为例,分别对拖曳力系数、管道单位长度质量、外径、内部介质密度、立管抗拉弯扭刚度和悬挂角度等参数进行敏感性分析,得出不同参数的敏感性情况,并在此基础上提出一些建议供实际工程设计参考.     

船用电器柜抗冲击设计研究

为增强船内部电器柜的抗冲击性能,采用有限元法对船内不同安装型式的电器柜结构进行了模态和抗冲击性能仿真分析,通过对比分析得出了使用撑杆加固型式安装的电器柜能显著提高船内电器柜的抗冲击性能的结论,并确定了电器柜抗冲击优化设计方案。     

Generalized Maximum Benefit Multiple Chinese Postman Problem

This research is focused on a generalization on the Max Benefit Chinese Postman Problem and the multiple vehicle variant of the Chinese Postman Problem. We call this generalization, the Generalized Maximum Benefit k-Chinese Postman Problem (GB k-CPP). We present a novel Mixed Integer Programming (MIP) formulation for the GB k-CPP. Four different cases of the model are discussed. The first case, performs arc-routing with profits and assumes that the origin and destination for each vehicle is the same for each cycle and is given by the user. The next case relaxes the assumption that the origin and destination for each vehicle should be the same and allows the users to select possible origins/destinations for vehicles. Case three gets the origin for each vehicle as input and produces a solution based on finding the best destination for each vehicle. The last case, that is very general, allows the optimization model to select possibly different locations for vehicle origin and destination, during each cycle. The different cases are applied to a security patrolling case conducted on the network of University of Maryland at College Park campus and the results are compared.     

Optimal joint distance and time toll for cordon-based congestion pricing

This paper addresses the optimal toll design problem for the cordon-based congestion pricing scheme, where both a time-toll and a nonlinear distance-toll (i.e., joint distance and time toll) are levied for each network user’s trip in a pricing cordon. The users’ route choice behaviour is assumed to follow the Logit-based stochastic user equilibrium (SUE). We first propose a link-based convex programming model for the Logit-based SUE problem with a joint distance and time toll pattern. A mathematical program with equilibrium constraints (MPEC) is developed to formulate the optimal joint distance and time toll design problem. The developed MPEC model is equivalently transformed into a semi-infinite programming (SIP) model. A global optimization method named Incremental Constraint Method (ICM) is designed for solving the SIP model. Finally, two numerical examples are used to assess the proposed methodology.     

船舶通信英语口语与听力课程标准

结合船舶驾驶员的岗位职责,依照现代职业教育理论和成果,设计了船舶通信英语口语与听力课程标准.对该课程的课程概述、培养目标、与前后课程的联系、教学内容与学时分配、学习资源、教师要求、学习场地与设施要求、考核方式与标准、学习情境设计进行了设计和描述,将船舶通信中典型工作任务转化为学习型任务.     

The generators of paratransit trips by persons with disabilities

Identifying the generators of paratransit trips by persons with disabilities is important to comprehend the current demand patterns and forecast future demand. Only a handful of studies have been conducted so far to identify the generators of paratransit trips and most focused on the home end of the trips. Given some of the inconsistencies in past studies and the scarcity of studies on the generators of trips away from home, this study attempts to identify the generators of paratransit trips beginning and ending at clients’ homes and away from home. It uses an extremely large dataset consisting of 1.91 million trips made by NJ TRANSIT’s Access Link clients, socioeconomic data from the American Community Survey, employment data from the Longitudinal Employer-Household Dynamics, and establishment data from Dun and Bradstreet. The analytical methods include an ordinary least squares model (OLS) and several spatial generalized linear mixed models (GLMM) to identify the characteristics of census block groups associated with Access Link trip generation at home and away from home, Geographic Information System (GIS) analysis to identify the types of establishments located in the immediate vicinity of drop-offs, and a multinomial logit model (MNL) to examine the relationship between the characteristics of the establishments in the vicinity of drop-offs and the characteristics of the dropped-off clients. Together, the various analyses provide useful insights about paratransit trip generators at the macro and micro levels. Some implications of the findings are discussed.     

汕头苏埃隧道方案设计关键技术研究

根据汕头苏埃隧道的建设条件,对工程方案设计中的几个技术难点进行研究,并提出解决方案。通过采用"多级分流"理念,实现隧道与北岸4条城市主干道的交通衔接;选择"抛石+排水板"方案解决海域深厚淤泥地层中的围堰设计;8度高烈度震区选择合理的抗震减震措施解决隧道结构抗震;采取双道密封垫和加大密封垫断面的防水设计,满足地震时管片接缝张开量大的防水要求;针对复杂地层,对盾构选型和配置提出建议;对海底凸起进入隧道内的硬岩进行爆破预处理,以降低盾构施工风险。