Influences on bicycle use

A stated preference experiment was performed in Edmonton in Canada to both examine the nature of various influences on bicycle use and obtain ratios among parameter values to be used in the development of a larger simulation of household travel behaviour. A total of 1128 questionnaires were completed and returned by current cyclists. Each questionnaire presented a pair of possible bicycle use alternatives and asked which was preferred for travel to a hypothetical all-day meeting or gathering (business or social). Alternatives were described by specifying the amounts of time spent on three different types of cycling facility and whether or not showers and/or secure bicycle parking were available at the destination. Indications of socio-economic character and levels of experience and comfort regarding cycling were also collected. The observations thus obtained were used to estimate the parameter values for a range of different utility functions in logit models representing this choice behaviour. The results indicate, among other things, that time spent cycling in mixed traffic is more onerous than time spent cycling on bike lanes or bike paths; that secure parking is more important than showers at the destination; and that cycling times on roadways tend to become less onerous as level of experience increases. Some of these results are novel and others are consistent with findings regarding bicycle use in work done by others, which is seen to add credence to this work. A review of previous findings concerning influences on cycling behaviour is also included.     

台湾海底隧道之接头与管段变化研析及对策

台湾唯一之海底隧道系采沉埋方式施工,该隧道不仅处于具高度盐份腐蚀之不利环境,且位于软弱地盘上.于营运二十余年后,轻微异状已有显现,如管段接头锈蚀、管体渗漏及管体裂损等异状.上述异状可能为接头构件变形、管体变位/变形及结构劣化等影响隧道安全之前兆,甚至降低其耐震能力;因该隧道肩负港区及区域经济发展之运输重任,如何藉由整体性体检进行安全评估及研订适当之维护补强对策,为计划执行重点;故本文将说明隧道接头、结构体等隧道重要构件之检测调查(如地球物理、钢筋腐蚀、裂缝深度、氯离子试验、防蚀电位、接头防水等项目)、数值分析及自动化监测(接缝计、单元沉陷仪、结构倾斜仪、电位计等)等综合评估结果及维护补强对策,以提供工程界日后参考.     

潜盾机在到达井外侧地盘中安全弃壳之案例研讨

捷运潜盾隧道皆位于人口密集之都会区,潜盾机的发进与到达常为潜盾隧道挖掘过程中风险较大的时间点,本研究拟以潜盾机到达弃壳作业为例,探讨其面临之风险,包括点井降水造成地盘地下水位变化和邻近台电345 kV高压电塔不均匀沉陷,以及站体连续壁因开挖所引致侧向变位使JSG地盘改良区产生缝隙水路,造成潜盾机开舱前渗水的风险.再者,依据工址抽降水期间竖管式水压计、水位观测井和地表、建物沉陷点监测数据分析抽降水引致地表沉陷影响范围,用以回馈将来遭遇类似工况的设计参考依据.潜盾机到达之安全弃壳作业包括以超级点井(SWP)工法尝试降低地下水位,并于松三层(EL.92.42m)和松五层(EL.72.42m)埋设竖管式水压计了解降水期间地下水位变化,同时监测邻近建物如台电高压电塔的倾斜及沉陷;其次,在潜盾机到达处先行进行JSG地盘改良,再以试水试验检核地盘止水性,潜盾机到达后即进行机壳背填灌浆、土压舱分阶排土及漏水确认.然后,潜盾机历经二次拆解,完成到达弃壳作业,最后进行镜面破除及隧道贯通.     

Climate change and the future Maritime Policy for the EU

A cross-cutting Maritime Policy can ensure that climate change threats and challenges in regards to seas and oceans are dealt with in a wide policy framework that takes into account the impacts that climate change may have on other sectors and vice versa.     

载人潜器应急解脱、抛弃装置设计及应用

阐述载人潜器应急解脱、抛弃装置的研制要求,设计思想,介绍人工操作的液压式应急解脱装置和人工操作的机械式应急抛弃装置的工作原理、设计方法、采用的材料及应用情况。     

Numerical modelling of fish eggs dispersion at the Patos Lagoon estuary — Brazil

The Patos Lagoon estuary is the most important nursery ground for commercially relevant species of fish and crustaceans in the South of Brazil, maintaining fisheries that sustain 3500 fisher families throughout the Rio Grande do Sul State coastline. Around 80% of the interior estuarine area is very shallow (< 2 m), and recruitment of fish eggs and larvae to the inner parts of the Patos Lagoon estuary is directly related to the circulation pattern in the area, which is controlled by local and non-local wind effects and freshwater discharge. The objective of this study is to investigate the processes controlling the transport of estuarine dependent fish eggs between the Atlantic Ocean and the Patos Lagoon estuary.An integrated numerical system based on a bi-dimensional hydrodynamic model and a Lagrangean transport model of passive particles is applied to a selection of scenarios representing the passage of weather fronts over the area. At this stage, fish eggs are represented as buoyant passive particles. Modelling results are compared against field data for the period under investigation (September/October 1999) and historical records. Short term results are analysed in terms of the meteorological conditions (wind direction, intensity and duration) controlling the transport of eggs to the inner parts of the estuary and the extension of their excursion. This experiment is the first attempt to couple biological and physical information to study fish eggs transport, and to enhance the current knowledge about recruitment of important fisheries resources in southern Brazil.     

Two-dimensional Continuum Modeling Approach to Transportation Problems

The continuum modeling approach to transportation models is now gaining much attention because of its advantages in dealing with dense-network models, macroscopic problems, and initial phase planning. This paper aims to provide a comprehensive review of the development and applications of the two-dimensional continuum modeling approach. The theoretical development and models with specific or arbitrary region configurations are first discussed, and then the applications of the continuum modeling approach to the determination of facility location, route choice, pedestrian flow, and policy and socio-economical analysis are reviewed. Finally, some prospective directions for future research are proposed.     

A study of train dwelling time at the hong kong mass transit railway system

This paper investigates the relationship between the dwelling time of trains and the crowding situations at Mass Transit Railway (MTR) stations in Hong Kong. Regression models were established for the dwelling delays of trains due to congestion at stations, and a simulation model making use of the Monte-Carlo technique is developed to assess the reliability of the estimated train dwelling time. Therefore, the distribution and the confidence interval of the train dwelling time can be predicted on the basis of observed boarding and alighting distributions.     

A note on trip matrix estimation from link traffic count data

In this note, a simple network equilibrium based approach for estimating a trip matrix using link traffic count data is proposed. In essence a combined distribution and assignment model is formulated in which the link flow data serve to furnish an estimate for the sum of the integrals of the link cost functions. A comparison of this model with others proposed previously is made.