The impact of the Polar Code on risk mitigation in Arctic waters: a “toolbox” for underwriters?

The existing risk weighing on vessel, crew and ecosystem in the Arctic and more globally in Polar waters promoted the adoption of the Polar Code (PC) early 2017, a mandatory international legal framework intended for enhanced safety and environmental protection. While the substance of the PC has been extensively analyzed, few studies have focused on the underlying relationships between the PC and underwriters. Based on an extensive literature review, documentary materials and interviews with insurance companies, this article conceptualizes the PC as a “toolbox” and analyzes how underwriters can exploit it in their work within the emerging Arctic market. The PC does not only regulate the navigation in Arctic waters in legal terms, but is also aimed at mitigating risks in the Polar areas through the identification of hazard sources and proceduralization of risk assessment. As a result we observe a certain “Polar Code paradox”. Even though the PC is a risk-based instrument and constitutes a key step for improving ship insurability, it has only limited capacity to assist underwriters in assessing risks and insuring vessels. Marine insurers still face a lack of data and high pending uncertainties leading them to exercise extreme caution with Arctic risks appraisal.     

The potential mitigation of CO2 emissions via modal substitution of high-speed rail for short-haul air travel from a life cycle perspective – An Australian case study

The objective of this study is to provide a strategic evaluation of the mitigation of CO₂ emissions via modal substitution of high-speed rail for short-haul air travel on the Sydney–Melbourne, Australia city-pair from a life cycle perspective. It has been demonstrated that when considering CO₂ emissions from vehicle operations, the modal shift from air to high-speed rail on this city-pair has the potential to provide a means of CO₂ mitigation. However, uncertainty exists with regard to the level of mitigation potential when considering the whole-of-life performance of the systems. Given the significant difference in the infrastructure requirements between the air mode and the high-speed rail mode, this study quantifies the life cycle CO₂ load attributable to each system and examines the effect on CO₂ mitigation potential. The study concluded that while the inclusion of the linehaul infrastructure did increase the CO₂ load associated with high-speed rail mode, it did not equate to or exceed the CO₂ load per trip as experienced by the air mode. The avoided annual life cycle CO₂ emission in the target year 2056 was 0.37 Mt representing an 18% reduction when compared to the air mode only on the city pair. In fact, the scenario comparison indicated that the substitution of high-speed rail for short-haul air travel on the city pair resulted in CO₂ emissions avoidance throughout the longitudinal period.     

Agent-based simulation framework for mixed traffic of cars,pedestrians and trams

In this paper, we report on the construction of a new framework for simulating mixed traffic consisting of cars, trams, and pedestrians that can be used to support discussions about road management, signal control, and public transit. Specifically, a layered road structure that was designed for car traffic simulations was extended to interact with an existing one-dimensional (1D) car-following model and a two-dimensional (2D) discrete choice model for pedestrians. The car model, pedestrian model, and interaction rules implemented in the proposed framework were verified through simulations involving simple road environments. The resulting simulated values were in near agreement with the empirical data. We then used the proposed framework to assess the impact of a tramway extension plan for a real city. The simulation results showed that the impact of the proposed tramway on existing car traffic would not be serious, and by extension, implied that the proposed framework could help stakeholders decide on expansion scenarios that are satisfactory to both tram users and private car owners.     

船舶低硫柴油系统设计的分析与优化

就新辟航线首制船“汉亚直达”集装箱船的低硫柴油系统,叙述了船舶低硫柴油系统的设计经验,从当前国内外对船用燃油硫含量的要求、应对方案到船舶低硫柴油冷却方式选择、低硫柴油冷却系统设计、高/低硫柴油转换、使用低硫柴油风险分析及处理等方面进行详细叙述,为业内同行提供参考。     

基于语义挖掘的快递运输货品风险评价研究

为提高快递运输的风险监测管控能力，降低因快递货品风险导致城市安全事件发生的可 能性，本文基于语义挖掘方法将快递运输货品描述转化为风险的量化表征，为快递运输风险评价 提供可量化的客观指标依据。基于网络大数据资源提供的法院判决书数据，将物品词条与判决 结果相关联，通过隐狄利克雷分布模型挖掘物品风险主题，结合模糊均值聚类方法，实现对快递 货品语义风险的量化表征与柔性划分。与传统方法中依赖检视人员查验既定违禁品清单后的主 观判断方法不同，本文充分挖掘网络文本数据中的可迁移知识，并应用于种类繁多的快递运输货 品，有效避免人工评价造成的漏检、错检情况。研究结果表明，本文方法具有较高的准确率与较 低的误报率，获得的风险评价值不再是0或1的是非判断，有利于开展多样化、针对性的风险预警 及应对措施。     

信号交叉口行人二次过街下右转车通行能力与延误估计模型

在充分分析典型四相位交叉口行人二次过街设置前、后的行人流与右转车流冲突的前提下，以行人过街时间占有率和行人群到达分布作为分析指标，利用可插车间隙理论得出行人单向通行和双向通行条件下的右转车通行能力计算公式；根据行人流随机消散和集中消散的不同特征，应用随机分布理论推导出右转车穿越行人流的延误模型；并通过算例对比分析行人二次过街设置前、后右转车通行能力和延误的变化值。结果表明，除了在少数行人流量比较大的情况下， 行人二次过街的设置会小幅度减少右转车的延误；在其他大多数情况下，行人二次过街设置后， 右转车的通行能力将受到限制，延误增大，其中，平均通行能力降低了16.68%，平均延误时间增大 了21%，所以，当右转车交通需求较大时，需同时考虑行人和右转车的交通运行状态，优化设计是否采用行人二次过街，避免右转车超出极限忍耐时间而增大与行人冲突的概率。     

Traffic modelling in system boundary expansion of road pavement life cycle assessment

This paper uses a case study of a UK inter-urban road, to explore the impact of extending the system boundary of road pavement life cycle assessment (LCA) to include increased traffic emissions due to delays during maintenance. Some previous studies have attempted this but have been limited to hypothetical scenarios or simplified traffic modelling, with no validation or sensitivity analysis. In this study, micro-simulation modelling of traffic was used to estimate emissions caused by delays at road works, for several traffic management options. The emissions were compared to those created by the maintenance operation, estimated using an LCA model. In this case study, the extra traffic emissions caused by delays at road works are relatively small, compared to those from the maintenance process, except for hydrocarbon emissions. However, they are generally close to, or above, the materiality threshold recommended in PAS2050 for estimating carbon footprints, and reach 5–10% when traffic flow levels are increased (hypothetically) or when traffic management is imposed outside times of lowest traffic flow. It is recommended, therefore, that emissions due to traffic disruption at road works should be included within the system boundary of road pavement LCA and carbon footprint studies and should be considered in developing guidelines for environmental product declarations of road pavement maintenance products and services.     

A comparative life-cycle energy and emissions analysis for intercity passenger transportation in the U.S. by aviation,intercity bus,and automobile

Intercity passenger trips constitute a significant source of energy consumption, greenhouse gas emissions, and criteria pollutant emissions. The most commonly used city-to-city modes in the United States include aircraft, intercity bus, and automobile. This study applies state-of-the-practice models to assess life-cycle fuel consumption and pollutant emissions for intercity trips via aircraft, intercity bus, and automobile. The analyses compare the fuel and emissions impacts of different travel mode scenarios for intercity trips ranging from 200 to 1600 km. Because these modes operate differently with respect to engine technology, fuel type, and vehicle capacity, the modeling techniques and modeling boundaries vary significantly across modes. For aviation systems, much of the energy and emissions are associated with auxiliary equipment activities, infrastructure power supply, and terminal activities, in addition to the vehicle operations between origin/destination. Furthermore, one should not ignore the embodied energy and initial emissions from the manufacturing of the vehicles, and the construction of airports, bus stations, highways and parking lots. Passenger loading factors and travel distances also significantly influence fuel and emissions results on a per-traveler basis. The results show intercity bus is generally the most fuel-efficient mode and produced the lowest per-passenger-trip emissions for the entire range of trip distances examined. Aviation is not a fuel-efficient mode for short trips (<500 km), primarily due to the large energy impacts associated with takeoff and landing, and to some extent from the emissions of ground support equipment associated with any trip distance. However, aviation is more energy efficient and produces less emissions per-passenger-trip than low-occupancy automobiles for trip distances longer than 700–800 km. This study will help inform policy makers and transportation system operators about how differently each intercity system perform across all activities, and provides a basis for future policies designed to encourage mode shifts by range of service. The estimation procedures used in this study can serve as a reference for future analyses of transportation scenarios.     

基于模糊综合评价法的城市综合管廊结构健康评价方法研究

为解决城市综合管廊结构健康状况评估结果无法量化和指导运维的问题，通过分析模糊综合评价理论在交通隧道结构健康评价方法研究中的应用，依照类比思想，利用该理论建立城市综合管廊结构健康状况评价体系。首先，依据有关养护规定和调研结果，基于不同需求分别建立管廊结构的本体完好状况和本体结构状况评价指标体系； 其次，以交通隧道和综合管廊养护经验为基础，划分各指标的分级判定标准； 然后，采用层次分析法，计算评价指标的权重分配； 最后，采用柯西分布型隶属函数和矩阵型隶属函数确定各指标的隶属度，建立一级和二级模糊综合评价模型，赋予评价向量中各评语相应分值，将评价向量单值化，判定管廊结构健康状况。采用所提出的评价方法应用于实际工程，所得评价结果与经验评判得到的结果相同。     

中越界河海事执法行为的风险规避

文中通过介绍中越边境河流——北仑河海事现场执法风险，分析执法风险存在的原因、表现形式，结合实际工作体会，探讨界河基层海事执法的风险防范