I want to ride it where I like: measuring design preferences in cycling infrastructure

Transportation - Sidewalk cyclists are a major concern to planners in many cities around the world: they are considerable in numbers, and increase the risk of injury not only to pedestrians but...     

无人驾驶地铁均衡发展

介绍了北美、欧洲和日本等国家无人驾驶地铁技术的现状及发展情况。     

默默的竞争者

既没有一级城市，也没有超级大港，山东省很少能像广东或江苏那样受到众人瞩目。但是人们却远远低估了山东省的重要性，Tom Miller在青岛为您报道。[编按]     

尊重

初习垂钓,先要学习尊重生命,懂得放手放生。他虽小,父亲只要不断向他重复,他会记得很牢。Lexus GS460,不太可能是任何人初学驾驶的教具。其实它被取消此一资格,并不因为自己有何罪过,只是售价有些昂贵,只是动力太过富裕。     

Travel patterns in Dutch metropolitan cities: The importance of external trips

Using a variety of data sources, decentralisation of population and employment in four Dutch urban areas (Amsterdam, Rotterdam, The Hague and Utrecht) over the last 20 years, is analysed. It is found that suburbanisation, plus an ever growing car share, has increased the number of external journeys related to the metropolitan cities enormously. With the use of the 1982 National Travel Survey, current travel patterns in and around the metropolitan cities are studied: the importance of external trips for urban transport planning shows clearly. They account for about half the number of city related car trips, and for nearly three quarters of the total vehicle kilometres of travel within the city.(requests for reprints)     

Exploring temporal fluctuations of daily cycling demand on Dutch cycle paths: the influence of weather on cycling

In the pursuit of sustainable mobility policy makers are giving more attention to cycling. The potential of cycling is shown in countries like the Netherlands, where cycling covers 25 % of all person trips. However, the effect of policy interventions on cycling demand is difficult to measure, not least caused by difficulties to control for changing context variables like weather conditions. According to several authors weather has a strong influence on cycling demand, but quantitative studies about the relationship are scarce. We therefore further explored this relationship, with the aim of contributing to the development of a generic demand model with which trend and coincidence in bicycle flows might be unraveled. The study is based on time-series between 1987 and 2003 of daily bicycle flows, collected on 16 cycle paths near two cities in the Netherlands. The regression analyses show that, not surprisingly, recreational demand is much more sensitive to weather than utilitarian demand. Most daily fluctuations (80 %) are described by weather conditions, and no less than 70 % of the remaining variation is locally constrained. The regression can therefore mainly be improved by incorporating path specific, as yet unknown, variables. We used the regression results to calculate weather-inclusive bicycle flow predictions and found indications of a downward trend in recreational demand. This trend has been off-set in the observed flows by more favorable weather conditions over the years considered.     

A probabilistic damage tolerance concept for welded joints. Part 1: data base and stochastic modelling

The present paper presents the necessary crack growth statistics and suggests stochastic models for a reliability analysis of the fatigue fracture of welded steel plate joints. The reliability levels are derived from extensive testing with fillet-welded joints for which the entire crack growth history has been measured, not only the final fatigue life. The statistics for the time to reach given crack depths are determined. Fracture-mechanics-derived crack growth curves are fitted to the measured experimental curves and the best fit defines the growth parameters involved for each test specimen. The derived statistics and distribution function for these parameters are used as variables in a Monte Carlo simulation (MCS). In addition a Markov model is developed as an alternative stochastic model. It is a Markov chain for which the discrete damage states are related to chosen crack depths in the material. This model works directly with the experimental time statistics. It is a “stochastic bulk approach” not involving any random variables or fracture mechanics modeling. Both models are fitted to the data base and scaled to in-service conditions. Both methods are compared and discussed. The aim is to provide data for the variables used in a MCS and to develop a Markov chain for fast reliability calculation, especially when predicting the most likely influence of numerous future inspections.     

这是库布齐

Jeep Wrangler共3部,Sahara长短版本各一,主角是Rubicon,由它们去挑衅中国第7大沙漠:内蒙古库布齐——去征服和嬉戏。     

迷幻公园

看过Nick Hornby在2007年写的Slam(砰!),才刚16岁的玩板少年Sam,意外地使初恋女友怀孕,简直崩溃。单亲妈妈生下他时才17岁,十足少女母亲,现在这位老妈刚刚32岁,仍然美丽诱人。要是你的哥们儿叫你喝酒都顺便邀请你老妈,你说你会不会很窘?     

汽车协议和标准

技师们每天按美国汽车工程师学会(SAE)的各个标准工作。但是这些标准从哪里来,那些数字又代表什么呢?