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HCM2000 Back of Queue模型(BQ模型)的计算值比实际调查值偏大,而且模型关于排队车辆的界定不能保证现场调查的客观性。提出了车辆拖延行为的定义,分析了拖延行为使BQ模型偏大的2种情况。建立了拖延行为模型,将车辆减速-停车等待-加速过程转化为温和减速-低匀速-温和加速的3阶段模型。通过低匀速行驶时间与停车时间之间的关系,可以得到车辆发生拖延行为的条件。建立了考虑拖延行为的排队长度与BQ模型之间的关系,并以首辆拖延车辆能否通过交叉口以及饱和度是否大于1为判别条件,提出了排队长度修正模型。通过实例验证了修正模型的可行性,而且修正模型可以保证现场调查的客观性和可操作性。 相似文献
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玻化砖色差的形成及克服 总被引:1,自引:0,他引:1
喻乐华 《华东交通大学学报》2001,18(1):52-54
比较系统地阐述了玻化砖主要缺陷之一-色差的类型、产生原因、影响因素及相应的克服办法。 相似文献
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为解决山区公路中驾驶视觉信息量难以量化的问题,对驾驶视野图像进行分割,根 据HSV颜色模型,提取视野图像的色调、饱和度、亮度值,再结合车速值,在驾驶视觉心理负荷的基础上,提出山区公路路域环境下的驾驶视觉信息量计算方法.通过实车实验,进行数据采集,并验证计算方法.计算结果表明,在半郁闭型空间行驶时,接收的视觉信息量最大;在郁闭型空间中,接收的信息量最小.计算结果与被试实际感受具有一致性,说明本文提出的驾驶视觉信息量计算方法具有可行性,可为路域环境的合理布设提供一定的技术参考. 相似文献
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O. V. Kopelevich S. V. Sheberstov O. Yunev O. Basturk Z. Z. Finenko S. Nikonov V. I. Vedernikov 《Journal of Marine Systems》2002,36(3-4)
Absolute values of chlorophyll a concentration and its spatial and seasonal variations in the Black Sea were assessed by using satellite CZCS and in situ data. Since the satellite CZCS had operated for the 1978–1986 period, CZCS data was used for assessing the past state of the Black Sea just before the onset of drastic changes observed in late 1980s. The approach used for the calculation of the absolute values of chlorophyll a concentration from CZCS data was based on the direct comparison of in situ chlorophyll a data and those of CZCS and by applying the algorithm developed for the transformation of CZCS data into chlorophyll a values. CZCS Level 2 data related with pigment concentration having a spatial resolution of 1 km at nadir were used. The daily Level 3 files were derived by binning Level 2 values into 4-km grid cells and the monthly and seasonal Level 3 files were created by averaging the daily Level 3 files over the corresponding period. In situ chlorophyll a data were obtained by spectrophotometric and fluorometric methods in 15 scientific cruises over the 1978–1986 period. Total number of ship-measured data used for the comparison with those CZCS values was 590.Chlorophyll a concentration (Chl) was derived from CZCS values (C) with regression equations Chl=kC; the coefficient of transformation k was calculated from six different data sets by taking into account distinctions between subregions and seasons. The reasons for difference in the k values have been analyzed.Statistical comparison of the chlorophyll a values measured in situ and those derived from CZCS data was based on log-transformed data and gave the following results: regression SLOPE=0.842, regression INTERCEPT=−0.081, coefficient of determination (R2)=0.806, root–mean–square ERROR=0.195. The mean monthly chlorophyll a distributions derived from CZCS data over 1978–1986 have been constructed and the mean seasonal chlorophyll a values in different regions have been calculated and analyzed. The significant difference in chlorophyll concentration between the western shelf regions and the open part of the Black Sea has been demonstrated, especially in warm season. At almost all seasons, the highest chlorophyll concentration is observed in the western interior shelf region which is under strong influence of Danube. The summer mean chlorophyll concentration in this region is 18 times higher than that in the open parts and about nine times higher than in the eastern shelf region. The greatest seasonal variations are observed in the open part of the Black Sea: chlorophyll concentration in cold season is four to six times higher than in summer and three to five times higher than in April and October. To the contrary, in the western interior shelf regions, the concentration is higher in May–October (about twice than that in November–March). Seasonal variations in the western outer shelf regions are smoothed out as compared with both the western interior shelf and the open regions. 相似文献
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电磁吸盘式电极是公路客车电热张拉蒙皮工艺装备的重要组成部分,是一种以普通薄钢板 A3作为衔铁的电磁铁本文对这种特殊要求的电磁铁进行了理论计算.试验结果表明,本文工作完全符合客车电热张拉蒙皮的实际工艺要求。 相似文献
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机车通用彩色液晶显示诊断装置 总被引:5,自引:3,他引:2
介绍了机车通用彩色液晶显示诊断装置的系统配置及各部分功能,着重介绍了该装置在机车上应用的工作原理和主要功能。 相似文献