高速公路交通控制与管理运营模式

根据中国现行的高速公路交通控制与管理运营模式存在的问题 , 以市场经济的要求为出发点 , 针对高速公路监控、通讯、收费等交通控制与管理系统技术密集、高度专业化的特点 , 提出了设计 (Design) -安装调试 (Installation) -运营管理 (Operations) 一体化经营模式 (简称 DIO模式 ) 。并给出了 DIO模式实施的一些基本原则。     

地主港模式及其在中国的发展

地主港模式是世界港口发展的趋势。首先明确了地主港的概念以及实行地主港模式的好处,接着分析了我国建立地主港模式的条件,在此基础上,提出了我国发展地主港模式的建议。     

混合动力客车模式切换多控制器的协调控制

分析了并联混合动力客车由纯电动驱动模式向发动机单独驱动模式切换的过程, 借鉴了切换系统的基本思想, 提出混合动力客车模式切换多控制器的协调控制策略; 按照离合器的状态将驱动模式切换过程划分为3阶段, 根据车辆运行所处的不同阶段, 设计了Fuzzy-PI控制器与滑模控制器对发动机与驱动电机进行动力协调控制; 以冲击度作为评价模式切换品质的量化指标, 在MATLAB/Simulink/Stateflow中建立了并联混合动力系统仿真模型, 搭建了整车试验平台, 分析了协调控制的效果。仿真结果表明: 未采用协调控制策略时, 在离合器滑摩阶段, 由于离合器两端转速差较大, 其传递摩擦转矩会产生约189N·m的扰动, 导致车速骤降, 反向的最大冲击度约为41.2m·s^-3; 采用协调控制策略后, 在整个模式切换过程中冲击度变化范围为-3⁴m·s^-3, 保证了动力传动系统输出的平稳性, 有效地抑制了驱动模式切换过程中对车辆所造成的冲击; 在一完整的驱动模式切换中, 实际车速的偏差小于5%, 冲击度控制在-5⁷m·s^-3, 试验结果与仿真结果基本一致, 证明了该策略的可行性与有效性。     

通风模式对住舱人员咳嗽液珠扩散过程的影响

针对邮轮上呼吸道疾病发病率高及缺乏相关定量研究的现状,采用计算流体力学方法分析了游客在密闭住舱内因为咳嗽产生的液珠在空气中的传播扩散过程,对空气流动采用非定常雷诺平均纳维-斯托克斯方程求解,对液珠扩散采用欧拉模型求解,计算工况考察了改变通风模式和加大通风量等方式降低液珠浓度的控制效果。研究结果表明:加大通风量在置换通风模式比混合通风模式下可更好地控制液珠的扩散,混合通风模式需要3次换气才能把住舱内的液珠基本排空,而置换通风模式仅需2次换气,且住舱内液珠平均浓度的下降服从指数分布。此外,游客睡姿对呼吸区域内液珠浓度峰值和吸入剂量有较大影响。     

Factors affecting temporal changes in mode choice model parameters

In travel demand forecasting models, parameters are often assumed to be stable over time. The stability of these parameters, however, has been questioned. This study investigates the factors affecting temporal changes in mode choice model parameters using a method proposed by the author that jointly utilises repeated cross-sectional data. In this method, the parameters are assumed to follow functional forms and the parameter changes are modelled endogenously. While the author’s previous studies assumed that all parameters are the same function of the same variable, this study assumes that different parameters are different functions of different variables, including time (year) and macro-economic variables. The paper describes a case study of a journey-to-work mode choice analysis for Nagoya, Japan, that examines 288 combinations of the functional forms and variables. The analysis found that the functions of time had serious over-fitting problems and that parameter changes are more closely related to economic factors.     

An integrated analysis of workers’ physically active activity and active travel choice behavior

Using Texas add-on sample data from the 2009 National Household Travel Survey, this study examines adult workers’ daily active choice decisions in the context of physical activity and attendant health benefits. The study looked at workers’ two choice behaviors: active activity and active travel. The first choice behavior, active activity, is developed as an ordered-response model based on the number of physically active recreational activities pursued during the workday. The second choice behavior, active travel, is developed as a binary-response model that examines workers’ active travel choices—whether or not the worker used any active mode of travel during the same workday. The study improves the understanding and knowledge of observed factors influencing workers’ physically active activity-travel behavior. The study also provides several observations regarding the role (and constraints) of employment in individuals’ active choices. Using a flexible copula modeling methodology, we explore the true correlation (or dependence) between the two behavior choices that could occur due to the presence of unobserved factors, suggesting a simultaneously low or simultaneously high propensity for being physically active across workers. The study findings suggest that transportation and public health policy makers can mutually benefit from encouraging workers to be physically active (from an activity and/or travel perspective). Overall, the study draws attention to the integrated nature of the public health and transportation fields, thereby providing a distinct view of active/inactive choice behavior. To our knowledge, this is the first study exploring a rich variety of components for workers’ active activity-travel behavior through a robust copula approach.     

The possible designation of the Mediterranean Sea as a SECA: A case study

In view of the ongoing discussions concerning the possible designation of the Mediterranean Sea as a Sulphur Emission Control Area (SECA), a modal split model was applied to a case involving the transportation of consolidated cargoes between Thessaloniki, Greece and industrial hubs of northern Germany. A road-only option was assessed against a combined-transport route involving a ferry (Greece–Italy) and a truck-on-train (Italy–Austria) service. The logit model used considers two variables as determinants of the modal selection: transport cost and time. The data are derived from interviews with a small transport service provider, typical for Greece, and are based on actual trips made (revealed preferences). The results predict that the designation of the Mediterranean as a SECA will cause a modal shift in favour of the road-only route by 5.2%, which under certain assumptions can reach 17.1%. However, the environmental implications of the resulting modal choices, calculated through the EcoTransIT World web based tool, are positive in relation to all emissions examined. This is attributed to the longer distance of the combined-transport option in comparison to the road-only one and, the poor environmental performance of the Ro-Pax vessels basically due to the need to maintain a relatively high speed.     

无人驾驶关键技术和典型场景应用分析

城市轨道交通无人驾驶系统是一种代替司机行使列车控制和驾驶功能的信号系统,可以做到无人值守,因此对各信号子系统有较高的性能要求。介绍了无人驾驶技术的概念及优势,综合分析了无人驾驶信号系统的关键技术和无人驾驶模式下的典型场景;结合迪拜、韩国无人驾驶线路开通后的运营状况,推广无人驾驶技术在城市轨道交通信号系统中的应用,并为广大工程设计人员提供参考。     

反舰导弹作战使用中的搜捕研究

通过对导弹雷达末制导技术以及末制导雷达搜捕方式的研究,强调了搜捕方式对反舰导弹作战使用的重大影响,对反舰导弹雷达末制导技术以及搜捕方式的发展进行了探讨。     

截锥形弹体穿甲薄板的数值计算研究

为了探讨薄板斜穿甲的破坏机理和弹体剩余速度,采用非线性动力学程序AUTODYN分析了截锥形弹体不同入射角度冲击下薄板的破坏模式,以及入射角度对靶板吸能和弹体剩余速度的影响,提出了靶板梨形孔的破坏模式．数值计算表明弹体斜穿甲时靶板吸收的能量与垂直穿甲时相差不大,斜穿甲时弹体在靶板上有滑移现象,并在高斜角低速撞击时弹体发生明显偏转,靶板也表现出不同的破坏模式。