眼球追踪技术在高速公路景观敏感区研究中的应用

介绍了利用摄像头进行眼球自动追踪的技术以及在高速公路景观敏感区研究中的应用,其主要原理是利用图像灰度曲线进行计算,分别获得水平和垂直灰度曲线,接着进行初步定位得到包含眼球在内的矩形区域,然后在此基础上对眼球位置进行精确计算,最后利用图像帧列计算眼球的相对移动轨迹和停留时间,由此可以记录试验者对高速公路景观不同区域的注意程度和关注时间,为高速公路景观研究和应用提供支持。     

康明斯柴油机及其附件总成的修理技巧

论述了康明斯柴油机在长期停用后、起动前应润滑其增压器全浮动轴承的必要性。在维修HIC8253AF/E18DA11涡轮增压器时,应注意增压器排气口漏机油、轴承损坏及空压机漏机油等故障。介绍了气缸盖、气缸体的修理技巧,以及诊断燃油继断器电磁阀、喷油泵泵头上的三角螺塞拧紧力矩不足或胶圈老化等故障的经验。     

内燃机泄放失效机油存在的问题及解决方法

指出了内燃机油底壳上放油螺丝在使用中存在的问题 ,分析由此而引起的后果 ,提出了排放失效机油过程中所需达到的要求 ,介绍了内燃机机油专用放油阀门     

Elasticities for taxicab fares and service availability

This study utilizes a unique dataset from New York City to examine the effects of taxi fare increases on trip demand and the availability of taxi service. The elasticity of trip demand with respect to fares is estimated to be –0.22; the elasticity of service availability with respect to the taxi fare is 0.28; and the elasticity of service availability with respect to total supply of service is near 1.0. These results have important implications for taxi regulatory decisions. First, fare increases do substantially increase industry revenues but at a lesser rate than the percentage increase in the fare. The implication for policy-makers is that fare elasticities must be carefully considered to obtain desired improvements in drivers' earnings. Second, service availability -- an important aspect of service quality that is generally overlooked during fare policy debates -- should be a central consideration in fare setting, given the considerable impact of fares on availability. Finally, where the supply of cabs needs to be expanded, the number of cabs can be significantly increased without harming the revenue stream of existing operators. This finding alleviates a major industry objection to issuing additional taxicab licenses.     

山岭重丘区公路选线探讨

山岭重丘区选线受地形、水文地质、路线交叉、公铁交叉等多种因素制约,线位的优劣是制约经济、合理、可行的重要因素。背景为山西省晋城市G207线过境段公路改线工程,结合项目选线过程中遇到的实际问题,提出本次选线的几点原则,通过不同线位的比较,最终确定较为合理、经济的线位,对类似工程项目具有一定的指导意义。     

城市交通能耗区的识别及等级划分方法研究

随着社会经济的发展，机动车保有量急剧增长，城市化过程中交通拥堵问题日趋严重，交通能源消耗加剧。为了降低由此带来的损失，需要及时探明路网中交通效率低、能耗高的区域，并采取有效的交通管理措施。通过研究交通状态与能耗的关系，进行相应的交通参数分析，建立能耗区识别及等级划分模型，计算得到3个等级能耗区的界定阈值分别为0．411和0．678。     

Competition and public service obligations in European aviation markets

This paper analyzes the effect of universal service policies on the airline markets of five European Union countries (France, Germany, Italy, Spain and the United Kingdom) in the period 2002–2010. Results show that airfare discount schemes for island residents raise demand and positively affect competition and the number of flights at the route level. These effects are evident in France and Italy, but are particularly marked in Spain. By contrast, public service obligations (PSOs) reduce competition on the protected routes, while their effect on the number of flights differs depending on national regulations. In Spain, routes protected with PSOs have greater flight frequencies than those on unprotected routes of similar characteristics, but in France, Italy and the UK the opposite result is found. The empirical model also finds that on routes with low-cost airlines market concentration is smaller and there is a larger number of flights. This result is relevant for the design of universal service policy, since in recent years low-cost airlines have entered a number of thin routes and have increased access to air transportation.     

山丘区行洪河道汛期清淤施工方案分析——以合肥二十埠河为例

对于需在汛期进行的山丘区行洪河道清淤施工,需克服汛期河道流量大、流速快、水位高带来的困难,保障施工安全的同时还需考虑工程施工对河道行洪的影响;若河道沿线建有多级蓄水建筑物、河道日常流量较大、周边用地情况复杂,则进一步增加了施工难度.以合肥二十埠河为例,对复杂情况下的山丘区行洪河道汛期清淤施工的特点和难点进行了分析,阐述此种条件下如何合理制定施工方案,以期能为类似工程提供参考.     

黄土地区铁路建设项目对地下水环境的影响研究

在我国西北地区,铁路项目的隧道工程越来越多,其对黄土含水层的地下水环境影响受到关注。为减轻隧道工程对地下水环境的影响,保证当地居民正常的生活用水及生态用水,以穿越黄土地区的铁路项目南惠隧道为例,在现场调查的基础上,介绍该隧道工程线路附近区域的水文地质条件及隧道外环境现状,重点分析该隧道工程的建设对线位附近地表水库、两侧村民饮用水井及对隧道洞顶植被可能产生的影响,并结合工程的具体情况,提出相应的环境保护措施,确保工程对地下水环境的影响降到最低。并对同类隧道工程给出工程环保选线上的一些建议。     

基于隧道断面面积变化的围岩稳定性判别

随着新奥法施工技术的广泛应用,围岩的动态变形越来越受到人们的关注。目前,我国主要是通过监测典型节点的位移来判断围岩变形的稳定性。典型节点的变形并不能代表整个围岩断面的变形状况,该方法存在一定的缺陷,因此提出采用隧道断面面积变化的方法来评价围岩变形的稳定性。采用突变理论数学方法计算Ⅳ级和Ⅴ级围岩在不同埋深条件下断面面积的变化值,得出面积变化的极限值,最终以此极限值作为判定围岩变形稳定的判据。