Do commuters adapt to in-vehicle crowding on trains?

Transportation - In-vehicle crowding on public transportation is a serious problem that transportation planners must address. Recent studies have emphasized that in-vehicle crowding impacts...     

船检履约与应对IMO强制审核要点与措施研究

为促进全球海上安全和防污染相关国际公约的有效执行,国际海事组织于2009年批准了"IMO成员国自愿审核机制"强制化,我国将于2021年接受IMO的强制审核。船检占强制审核政府义务条款大部分内容,其被视为IMO进行强制审核的重点领域。因此,本文拟针对IMO履约规则及相关国际公约中有关船检的管理要求,对我国海事船检履约情况进行评估,分析我国船检海事立法与管理方面存在的问题,提出我国针对船检履约与应对IMO强制审核的要点及改进措施,以满足2021年IMO强制审核的要求。     

船舶压载舱沉积物接收处置现状、问题及履约管理对策

《国际船舶压载水和沉积物控制与管理国际公约(2004)》要求妥善处理和处置压载舱沉积物,以防止有害生物入侵。为研究履约现状,选取13家从事压载水沉积物清理、接收及处理作业的修船厂进行了系统调研,结果表明普遍存在防污染措施不全、接收处理作业不规范、接收设施技术标准缺失、管理要求不明确等问题。在分析压载水沉积物的来源、危害、产生量等特性的基础上,结合公约和国内要求,从标准规范完善、监管部门协作、接收设施配套、公约法规宣贯和科技研发支撑等方面分析提出了履约对策。研究成果为有关压载水沉积物相关标准规范、技术政策的制定提供参考,有助于加强压载舱沉积物防污染管理,提升国际公约履行水平。     

Analysis of dynamic decision-making in a bicycle-sharing auction using a dynamic discrete choice model

For clarifying the usefulness and practical issues of a tradable permit system empirically, we implemented a tradable permit system for a bicycle-sharing service in Yokohama city, Japan. We analyzed both travel and transaction behavior within this system. Many activity factors, such as the amount of free time in each day, home location and travel mode to the bicycle port, were shown to affect the transaction of tradable permits. The results of the pilot program indicated that inefficient allocation of tradable permits occurred when participants postponed their decision-making because of uncertainty. To determine the reason for this effect and the contributing factors, we created a dynamic discrete choice model to describe the choice results and timing. The estimation result indicated that the option value of postponing decision-making caused the transactions to be performed at the last minute, and that this effect blocked the liquidity of the permits trade. In addition, because the result reveals that there was heterogeneity in the time discount factor, the initial allocation of permits was found to be important for efficient allocation.

     

比较安全学方法在民航安全管理模型中的应用研究

探索民航安全管理中模型的引用发展，基于比较安全学方法，对比分析ICAO安全管理手册中SHELL模型和REASON模型。根据比较安全学的研究模式，构建了2个模型基于时间维、知识维和空间维的三维比较研究模式；从时间维角度，比较分析2个模型的开发思路和评价侧重点；从知识维角度，对比分析2个模型在组成要素和功能作用上的不同；从空间维角度，对2个模型的适用范围进行了比较。研究结果表明，2个模型在民航安全管理的应用领域和价值有相似性，但在风险致因分析侧重点、分析路径、分析范畴等方面存在差异。在不同安全管理需求方面2个模型存在各自的优势，因此在今后的模型应用以及新模型的开发可借鉴2个模型的优点。      

Fatigue strength improvement for ship structures by Ultrasonic Peening

Ultrasonic Peening has attracted recent attention as a fatigue strength improvement method. The main features of Ultrasonic Peening are generation of compressive residual stress and smoothing of weld toe radius. However, for ship structures, various loads act on the hull structure over a ship??s life, including the construction period, and the compressive stress field of structural members generated by Ultrasonic Peening may change. In order to verify the technique's benefits to ship structures, the influence of load history on the improvement effects on fatigue strength by Ultrasonic Peening needs to be clarified. In this paper, the improvement effects on fatigue strength by Ultrasonic Peening for welding joints were confirmed by experiments with several joint type specimens. In addition, fatigue tests modeling launching, when the stress conditions of a ship's structure changes significantly, were carried out in order to clarify the influence of load history in a ship??s life. Consequently, some cases that have the possibility of decreasing or increasing the improvement effects on fatigue strength by Ultrasonic Peening were clarified, and some efficient methods of Ultrasonic Peening for ship structures were suggested.