Data of traffic flow, speed and density are required for planning, designing, and modelling of traffic stream for all parts of the road system. Specialized equipments such as stationary counts are used to record volum...Data of traffic flow, speed and density are required for planning, designing, and modelling of traffic stream for all parts of the road system. Specialized equipments such as stationary counts are used to record volume and speed;but they are expensive, difficult to set up, and require periodic maintenance. The moving observer method was proposed in 1954 by Wardrop and Charlesworth to estimate these variables inexpensively. Basically, the observer counts the number of vehicles overtaken, the number of vehicles passed, and the number of vehicles encountered while traveling in the opposite direction. The trip time is reported for both travel directions. Additionally, the length of road segment is measured. These variables are then used in estimating speeds and volumes. In a westbound direction from Interstate Highway 30 (I-30) in the DFW area, this study examined the accuracy and feasibility of this method by comparing it with stationary observer method as the standard method for such counts. The statistical tests were used to test the accuracy. Results show that this method provides accurate volume and speed estimates when compared to the stationary method for the road segment with three lanes per direction, especially when several runs are taken.展开更多
Based on data of number of fog and haze days in Baoji City from 1981 to 2013,the changing trends and mutation of number of fog and haze days in Baoji over the past 33 years were analyzed by using trend coefficient,ten...Based on data of number of fog and haze days in Baoji City from 1981 to 2013,the changing trends and mutation of number of fog and haze days in Baoji over the past 33 years were analyzed by using trend coefficient,tendency rate,linear regression analysis,anomaly percentage,Mann-Kendall mutation test and sliding t test.The results showed that during the 33 years,the number of fog and haze days in Baoji declined by 16.253d/10 a,and there was a cyclical turbulence every 6,15 or 28years.The frequency of fog and haze weather was the highest in winter,followed by spring and autumn,while it was the lowest in summer.According to the anomaly percentage of the number of fog and haze days in 12 months during 1981-2013,the anomaly percentage changed most greatly in July,followed by September,October,April,May,June,August,February and March,but it fluctuated less greatly in January.The number of fog and haze days from 1981 to 2013had obvious mutation trends in a single year and a single season,and mutation types are different.展开更多
目的探讨结核感染T细胞斑点试验(T-cell spot of Tuberculosis,T-SPOT.TB)在手、腕部腱鞘结核诊断中的临床应用价值。方法通过对2012年1月至2018年1月我院收集64例怀疑手、腕部腱鞘结核临床资料进行回顾性分析,根据病理诊断及临床表现...目的探讨结核感染T细胞斑点试验(T-cell spot of Tuberculosis,T-SPOT.TB)在手、腕部腱鞘结核诊断中的临床应用价值。方法通过对2012年1月至2018年1月我院收集64例怀疑手、腕部腱鞘结核临床资料进行回顾性分析,根据病理诊断及临床表现判断有无结核分枝杆菌感染;全部病例均经过T-SPOT.TB和胶体金标法分别进行体外γ-干扰素释放试验和血清结核抗体检测,采用Kappa、χ^(2)检验进行统计学分析。结果共收集分析相关病例64例,其中诊断为手、腕部腱鞘结核(结核病例)21例,非手、腕部腱鞘结核(非结核病例)43例。经T-SPOT.TB检测,结核病例阳性者20例,非结核病例阴性者40例,灵敏度为95.2%,特异度为93.0%,阳性预测值为87.6%,阴性预测值为97.6%。经胶体金标法检测血清结核抗体,结核病例阳性者5例,非结核病例阴性者37例,灵敏度为23.8%,特异度为86.0%,阳性预测值为45.4%,阴性预测值为69.8%。与临床诊断比较,T-SPOT.TB和胶体金标法的Kappa值分别为0.862和0.112,T-SPOT.TB比胶体金标法具有更好的一致性,且灵敏度、阳性预测值和阴性预测值均明显更高,差异有统计学意义(P<0.05)。结论T-SPOT.TB在手、腕部腱鞘结核诊断中具有良好的辅助诊断价值。展开更多
文摘Data of traffic flow, speed and density are required for planning, designing, and modelling of traffic stream for all parts of the road system. Specialized equipments such as stationary counts are used to record volume and speed;but they are expensive, difficult to set up, and require periodic maintenance. The moving observer method was proposed in 1954 by Wardrop and Charlesworth to estimate these variables inexpensively. Basically, the observer counts the number of vehicles overtaken, the number of vehicles passed, and the number of vehicles encountered while traveling in the opposite direction. The trip time is reported for both travel directions. Additionally, the length of road segment is measured. These variables are then used in estimating speeds and volumes. In a westbound direction from Interstate Highway 30 (I-30) in the DFW area, this study examined the accuracy and feasibility of this method by comparing it with stationary observer method as the standard method for such counts. The statistical tests were used to test the accuracy. Results show that this method provides accurate volume and speed estimates when compared to the stationary method for the road segment with three lanes per direction, especially when several runs are taken.
基金Supported by the National Natural Science Foundation of China(41071359)
文摘Based on data of number of fog and haze days in Baoji City from 1981 to 2013,the changing trends and mutation of number of fog and haze days in Baoji over the past 33 years were analyzed by using trend coefficient,tendency rate,linear regression analysis,anomaly percentage,Mann-Kendall mutation test and sliding t test.The results showed that during the 33 years,the number of fog and haze days in Baoji declined by 16.253d/10 a,and there was a cyclical turbulence every 6,15 or 28years.The frequency of fog and haze weather was the highest in winter,followed by spring and autumn,while it was the lowest in summer.According to the anomaly percentage of the number of fog and haze days in 12 months during 1981-2013,the anomaly percentage changed most greatly in July,followed by September,October,April,May,June,August,February and March,but it fluctuated less greatly in January.The number of fog and haze days from 1981 to 2013had obvious mutation trends in a single year and a single season,and mutation types are different.
文摘目的探讨结核感染T细胞斑点试验(T-cell spot of Tuberculosis,T-SPOT.TB)在手、腕部腱鞘结核诊断中的临床应用价值。方法通过对2012年1月至2018年1月我院收集64例怀疑手、腕部腱鞘结核临床资料进行回顾性分析,根据病理诊断及临床表现判断有无结核分枝杆菌感染;全部病例均经过T-SPOT.TB和胶体金标法分别进行体外γ-干扰素释放试验和血清结核抗体检测,采用Kappa、χ^(2)检验进行统计学分析。结果共收集分析相关病例64例,其中诊断为手、腕部腱鞘结核(结核病例)21例,非手、腕部腱鞘结核(非结核病例)43例。经T-SPOT.TB检测,结核病例阳性者20例,非结核病例阴性者40例,灵敏度为95.2%,特异度为93.0%,阳性预测值为87.6%,阴性预测值为97.6%。经胶体金标法检测血清结核抗体,结核病例阳性者5例,非结核病例阴性者37例,灵敏度为23.8%,特异度为86.0%,阳性预测值为45.4%,阴性预测值为69.8%。与临床诊断比较,T-SPOT.TB和胶体金标法的Kappa值分别为0.862和0.112,T-SPOT.TB比胶体金标法具有更好的一致性,且灵敏度、阳性预测值和阴性预测值均明显更高,差异有统计学意义(P<0.05)。结论T-SPOT.TB在手、腕部腱鞘结核诊断中具有良好的辅助诊断价值。
