Challenges and Benefits in the Design of Coastal Walking and Cycling Amenities: Toward a More Integrated Coastal Management Approach

The planning and development of pedestrian and cycling amenities in coastal urban environments is a challenging process because a wide range of policies and considerations must be taken into account. Among these, the concepts of sustainability and more recently, resilience, have been gaining prominence. Green Infrastructure design approaches can integrate aspects of both sustainability and resilience, providing multiple services within single development projects. This study focuses on Dublin and examines a range of amenity projects at various stages of development that relate to the provision of new coastal walking and/or cycle routes. These are initially contextualized at the city level before focusing specifically on challenges and benefits associated with the design and implementation of such projects. Based on our findings, recommendations are made for optimizing the potential of future projects to effectively integrate with other initiatives so as to deliver broader policy objectives. A simple sequential model is presented that should assist developers and decision-makers to take a more integrated, multidisciplinary approach to meeting policy goals when planning and developing coastal amenities. Finally, this is remodeled into a set of considerations that are generally applicable to coastal development proposals of significant scale.     

斜壁结构的水动力收敛方法研究

在分析波浪中的船舶运动或者计算大型结构的水动力系数时,往往采用时域格林函数方法。时域格林函数的一个重要局限性在于它在计算具有倾斜壁面的水动力系数时,结果很容易发散。时域格林函数本身的奇异性以及高频振动特性显然是水动力发散的一个重要原因。但即使该奇异性通过增加粘性以及表面张力的方式使之消失,计算具有斜壁结构的水动力时,发散现象依然存在。因此,该文提出一种滤波方法,除去时域格林函数的高频部分,留下其低频部分,并定义滤波系数,从而使作用于斜壁结构上的水动力值收敛。通过文中结果与频域兴波格林函数法的比较来确定最优滤波系数。结果表明：最优滤波系数几乎与运动幅值无关,但会受到运动频率以及物面形状的影响。     

高等级公路养护质量评价体系研究

从公路养护管理的需求出发,将高等级公路作为一类单独的评价对象,依据其使用性能要求,建立了高等级公路养护质量评价流程框架、指标体系,形成了完整的高等级公路养护质量评价体系。针对高等级公路养护质量评价特性,提出了定性、定量相结合的养护质量评价数据采集方法。采用权重模型计算不同层次的养护质量评价指标并在现场评分试验的基础上,采用多元统计理论对模型参数进行回归分析,得出了不同评价模型参数值。     

甲板上浪问题的二维数值模拟

以连续性方程和N-S方程为控制方程,采用源造波理论和技术,建立了具有造波和消波功能的二维数值波浪水槽,并使用VOF方法追踪自由面来模拟二维情况下的甲板上浪问题.文中就迎浪状态下的固定FPSO和横浪状态下的运动船体断面模型所遭遇的甲板上浪现象分别进行了数值模拟研究.船体的运动规律通过势流理论计算结果给定,在上浪现象模拟计算时,船体的运动采用移动网格技术实现.研究表明,计算结果与试验结果相当吻合,该方法可以用于甲板上浪现象的预报和模拟,可以用于分析预报甲板上浪对浮体的破坏作用.     

基于绿色交通理念的深圳市盐田区交通规划探索与实践

绿色交通已经成为建设低碳社会的有效抓手,是当今世界城市交通发展的必然趋势。首先介绍了绿色交通的内涵与基本特征,提出了绿色交通的发展内容与模式;在借鉴国内外绿色交通发展经验的基础上,并在深圳市绿色交通体系及模式的指引下,对深圳市国家生态城区——盐田区进行了绿色交通规划的探索。结合盐田区城市土地空间不足、生态资源受约束的现实条件,采取了空间差异性交通发展模式,并着重分析了地区公共交通系统、自行车、山海步行系统的发展规划思路。     

干线交叉口信号灯线控系统配时设计实例分析

对城市主干道进行"绿波"信号配时设计,可以最大限度地节省车辆停留及等待时间,提高道路设施的综合效益。在交通调查的基础上,对金华市八一南街与李渔路、宾虹路相交的十字交叉口主干道方向进行线控配时方案设计,并利用VISSIM交通模拟软件对线控配时方案进行仿真验证,结果显示通过线控方案设计可以使车辆在交叉口平均延误时间明显减少。     

基于ANP和粗糙集计算权重的绿色铁路客站评估

建设满足"节能环保"要求的绿色铁路客站,是我国铁路发展的趋势所在,因此铁路客站的绿色等级评估是极有必要的。通过建立绿色铁路客站"四节一环保"评价指标体系,以网络层次分析法(ANP)确定指标主观权重,经典粗糙集理论确定指标客观权重,再通过最小相对熵原理对二者进行优化结合,最后用得出的指标综合权重对银川新铁路客站进行绿色星级评估。结果表明:该权重确定方法既克服了因未考虑各指标之间的依存反馈关系而使主观权重不够准确的弊端,又利用相对熵原理优化并减小了主、客观权重结合的偏差,得出科学合理的组合权重,体现本文指标权重确定方法的有效性和优越性,为更加准确地评估铁路客站的绿色等级提供参考。     

Smarter and more connected: Future intelligent transportation system

Emerging technologies toward a connected vehicle-infrastructure-pedestrian environment and big data have made it easier and cheaper to collect, store, analyze, use, and disseminate multi-source data. The connected environment also introduces new approaches to flexible control and management of transportation systems in real time to improve overall system performance. Given the benefits of a connected environment, it is crucial that we understand how the current intelligent transportation system could be adapted to the connected environment.     

Exploring spatial variety in patterns of activity-travel behaviour: initial results from the Toronto Travel-Activity Panel Survey (TTAPS)

Studies of urban travel behaviour typically focus on weekday activities and commuting. This is surprising given the rising contribution of discretionary activities to daily travel that has occurred during the last few decades. Moreover, current understanding of the relationship between travel behaviour and land use remains incomplete, with little research carried out to explore spatial properties of activity-travel behaviour during the off-peak and weekend time periods. Weekend behaviours, for example, influenced by the availability of time and the spatiotemporal distribution of “weekend” destinations, likely produce spatially and temporally distinct activity-travel patterns. Using data from the first wave of the Toronto Travel-Activity Panel Survey (TTAPS), this paper examines an area of research that has received little attention; namely, the presence of spatial variety in activity-travel behaviour. The paper begins by looking at the extent to which individuals engage in spatially repetitive location choices during the course of a single week. Area-based measures of geographical extent and activity dispersion are then used to expose differences in weekday-to-weekend and day-to-day activity-travel patterns. Examination of unclassified activities carried out over a 1 week period reveals a level of spatial repetition that does not materialise across activities classified by type, travel mode, and planning strategy. Despite the inherent spatial flexibility offered by the personal automobile, spatial repetition is also found to be surprisingly similar across travel modes. The results also indicate weekday-to-weekend, and day-to-day fluctuations in spatial properties of individual activity-travel behaviour. These findings challenge the utility of the short-run survey as an instrument for capturing archetypal patterns of spatial behaviour. In addition, the presence of a weekday-to-weekend differential in spatial behaviour suggests that policies targeting weekday travel reduction could have little impact on travel associated with weekend activities.

格林函数在船舶磁场计算中的应用

文章首先通过引入半空间区域的格林函数,推导出船舶空间磁场分布的理论计算公式;然后,应用离散方法将双重积分转化为双重求和,得出了可用于船舶空间磁场工程计算的实际公式,具有实用价值。