通勤是具有周期性和稳定性的城市居民出行行为,是城市发展规划和公共交通管理的重要研究内容。出租车GPS(Global Position System,全球定位系统)轨迹数据在一定程度上反映了城市交通状况和市民出行模式。针对出租车区域性通勤模式识别问...通勤是具有周期性和稳定性的城市居民出行行为,是城市发展规划和公共交通管理的重要研究内容。出租车GPS(Global Position System,全球定位系统)轨迹数据在一定程度上反映了城市交通状况和市民出行模式。针对出租车区域性通勤模式识别问题,本文提出一种基于改进K-means算法的通勤交通小区识别方法。该方法主要包括3个步骤:划分交通小区、生成交通小区之间的流量转移矩阵和识别通勤交通小区对。参考现有的交通小区划分方法,本文提出一种基于细粒度单元的自下而上的交通小区划分方法。在通勤交通小区对识别模型中,以高峰时段的流量及其离散系数作为输入特征,基于改进K-means算法识别通勤交通小区对。最后,基于重庆市出租车GPS数据集进行实验验证,结果表明该方法效果显著。展开更多
The Longmenshan-Longriba region is located on the eastern edge of the Tibetan Plateau, and is an ideal place to study the eastward extrusion and uplift mechanism of the plateau. Previous studies on this area mainly fo...The Longmenshan-Longriba region is located on the eastern edge of the Tibetan Plateau, and is an ideal place to study the eastward extrusion and uplift mechanism of the plateau. Previous studies on this area mainly focused on tectonic activity and seismic hazard, with few studies giving its overall deformation characteristics and dynamic mechanism. This paper uses the latest dense GPS data, combined with precise Leveling data to analyze the kinematic characteristics and deformation mode of the Longmenshan fault zone (LMSF) and the Longriba fault zone (LRBF). The results show that both the Longmenshan fault zone and the Longriba fault zone have certain right-lateral strike-slip and thrusting, indicating that they play an important role in adjusting strain distribution and absorbing tectonic deformation;The strain-rate field on the Longriba fault zone is broadly distributed, suggesting that the deformation field is at least partially coupled;while the strain-rate field on the Longmenshan fault zone presents a non-uniform distribution, indicating different dynamic sources acting on segments. The high strain rate areas revealed in this study points us to the high-risk area for future earthquakes. The present-day vertical motion velocity field in the region obtained from Leveling and GPS data shows a mismatch between the regional deformation field and active tectonics, which can be explained by the incomplete coupling of deformation between the lower and upper crust.展开更多
Al Zn Mg Cu系合金在较低温度时效时,形成2种类型的GP区:GP(Ⅰ)区和GP(Ⅱ)区。选用7075,7075+0.58%Li,7075+0.89%Li和7075+1.0%Li4种合金进行343K,240h和393K,24h时效,以获得GP区,并通过DSC实验结果,用Avrami Johnson Mehl(AJM)表达式...Al Zn Mg Cu系合金在较低温度时效时,形成2种类型的GP区:GP(Ⅰ)区和GP(Ⅱ)区。选用7075,7075+0.58%Li,7075+0.89%Li和7075+1.0%Li4种合金进行343K,240h和393K,24h时效,以获得GP区,并通过DSC实验结果,用Avrami Johnson Mehl(AJM)表达式计算了GP区溶解动力学参数,从而定量地研究Li对7075合金GP区转变的影响。结果表明:经过343K,240h时效后,含Li的7075合金的GP(Ⅰ)区溶解激活能较7075合金的略低,Li促进GP(Ⅰ)区的形成;经过393K,24h时效后,2种合金GP区溶解激活能相差不大。展开更多
文摘通勤是具有周期性和稳定性的城市居民出行行为,是城市发展规划和公共交通管理的重要研究内容。出租车GPS(Global Position System,全球定位系统)轨迹数据在一定程度上反映了城市交通状况和市民出行模式。针对出租车区域性通勤模式识别问题,本文提出一种基于改进K-means算法的通勤交通小区识别方法。该方法主要包括3个步骤:划分交通小区、生成交通小区之间的流量转移矩阵和识别通勤交通小区对。参考现有的交通小区划分方法,本文提出一种基于细粒度单元的自下而上的交通小区划分方法。在通勤交通小区对识别模型中,以高峰时段的流量及其离散系数作为输入特征,基于改进K-means算法识别通勤交通小区对。最后,基于重庆市出租车GPS数据集进行实验验证,结果表明该方法效果显著。
文摘The Longmenshan-Longriba region is located on the eastern edge of the Tibetan Plateau, and is an ideal place to study the eastward extrusion and uplift mechanism of the plateau. Previous studies on this area mainly focused on tectonic activity and seismic hazard, with few studies giving its overall deformation characteristics and dynamic mechanism. This paper uses the latest dense GPS data, combined with precise Leveling data to analyze the kinematic characteristics and deformation mode of the Longmenshan fault zone (LMSF) and the Longriba fault zone (LRBF). The results show that both the Longmenshan fault zone and the Longriba fault zone have certain right-lateral strike-slip and thrusting, indicating that they play an important role in adjusting strain distribution and absorbing tectonic deformation;The strain-rate field on the Longriba fault zone is broadly distributed, suggesting that the deformation field is at least partially coupled;while the strain-rate field on the Longmenshan fault zone presents a non-uniform distribution, indicating different dynamic sources acting on segments. The high strain rate areas revealed in this study points us to the high-risk area for future earthquakes. The present-day vertical motion velocity field in the region obtained from Leveling and GPS data shows a mismatch between the regional deformation field and active tectonics, which can be explained by the incomplete coupling of deformation between the lower and upper crust.
