为解析建成环境对共享单车不同时段借还车量的非线性作用,本文以2016年上海摩拜共享单车和网络公开数据为基础,利用梯度提升决策树,建立共享单车工作日,非工作日及工作日早、晚高峰借还车量模型。研究结果显示:变量影响程度方面,街道至...为解析建成环境对共享单车不同时段借还车量的非线性作用,本文以2016年上海摩拜共享单车和网络公开数据为基础,利用梯度提升决策树,建立共享单车工作日,非工作日及工作日早、晚高峰借还车量模型。研究结果显示:变量影响程度方面,街道至市中心距离对4个时段共享单车借还车量具有稳定且突出的作用,相对重要度超过17%;路网密度、非机动车道占比、人口密度影响次之,但在4个时段作用波动较大。非线性关系方面,街道至市中心距离、非机动车道占比、人口密度、就业POI(Point of Interest)密度与各时段共享单车借还车量呈复杂非线性关系,阈值效应显著;路网密度、住宅POI密度则与之总体负相关和正相关。同时段下,建成环境对早晚高峰时期的共享单车借还车量非线性作用差异明显,与高峰时期单车骑行的潮汐性特征相一致,非机动占比与街道中心邻近度、就业POI密度对高峰时段单车骑行作用有明显的协作性作用。展开更多
共享单车调配是优化城市交通资源配置的重要手段,但目前的最优路径调配方法往往对单车系统规模敏感。为此,研究一种分时段、区域间调配的共享单车投放方法,提出了带约束的游牧算法(nomad algorithm with constraints,NCA)求解调配模型...共享单车调配是优化城市交通资源配置的重要手段,但目前的最优路径调配方法往往对单车系统规模敏感。为此,研究一种分时段、区域间调配的共享单车投放方法,提出了带约束的游牧算法(nomad algorithm with constraints,NCA)求解调配模型的最优解。将单车调配问题建模为以单车流量为约束、以最小化运营损耗为目标的优化问题;提出求解上述模型的NCA算法,预测投放区域单车存量和区域间转移量,相比无约束的原游牧算法,改进了局部搜索和全局寻优策略,优化了部落初定位方法;基于预测的存量和转移量得出分时段区域间单车的调配方案。在上海和纽约相关数据集上的对比实验结果表明,运行时长约为其他方法的15%,租赁需求响应率高于分支定界算法0.15%,单车总数和运营损耗比遗传算法降低了约10%,验证了该方法具有更高的优化效率和用户需求响应率。展开更多
自行车设定(Bike Fitting)是指利用运动生物力学、人体工程学等知识去分析自行车各个部件最匹配骑行者的设定参数,再使用相关工具去调试或优化自行车,主要涉及鞍座高度、鞍座位置角度、鞍座形状、车把和车架、曲柄长度以及脚踏6个方面...自行车设定(Bike Fitting)是指利用运动生物力学、人体工程学等知识去分析自行车各个部件最匹配骑行者的设定参数,再使用相关工具去调试或优化自行车,主要涉及鞍座高度、鞍座位置角度、鞍座形状、车把和车架、曲柄长度以及脚踏6个方面。适配的自行车设定能有效预防长期骑行中出现的非创伤性运动损伤并提升运动表现。本研究通过对中国知网、Web of Science和PubMed数据库中国内外有关自行车设定对骑行影响的研究进行综述和评价,让更多专业教练、科研人员以及运动员等从业者了解并重视这方面的知识,为减少骑行导致的运动损伤和提升运动员骑行表现提供借鉴和指导。展开更多
Bicycling constitutes an integral component of sustainable non-motorized means of travel. Despite the immense benefits of bicycling, the modal share of bicycling is quite low, specifically among young and low-income c...Bicycling constitutes an integral component of sustainable non-motorized means of travel. Despite the immense benefits of bicycling, the modal share of bicycling is quite low, specifically among young and low-income commuters e.g., college and university students. This study explores the perceptions of and barriers to bicycling of the campus community at the University of Tennessee, Knoxville with the aim to identify the factors that could enhance bike use among students at the university campus as well as highlight the barriers that keep young population away from biking. An online survey about bike use at the university campus was administered and responses to the survey were recorded. On the methodological front, a binary logit model was estimated with students’ willingness to use bikes at campus as the dependent variable. The survey results revealed that about 47% of the students considered vehicular traffic as the reason for feeling unsafe while biking and emphasized having separate bike routes. Most of the respondents highlighted the need to change clothes after biking in summer or carry things as the reason for not selecting bikes as a mode of transport at the campus, whereas inadequate bike lanes, paths, or trails, insufficient lighting along bike routes, and the lack of adequate bicycle parking were highlighted as the major barriers deterring bike use within the campus. The study suggests development of a campus bike network with proper bike lanes, bike runnels, installation of safety cameras and better lighting at the campus, and bike-supporting infrastructure such as communal showers to be provided in campus buildings to encourage bike use among university students. The study findings can assist campus transportation planners in devising a sustainable campus transportation plan incorporating the influencing factors and deterrents of bike use in a university campus setting.展开更多
Objectives: The primary objective was to characterize the range of Knowledge, Attitude, and Practice (KAP) of Helmet use in children amongst parents to prevent head injuries and death. Methods: This is a cross-section...Objectives: The primary objective was to characterize the range of Knowledge, Attitude, and Practice (KAP) of Helmet use in children amongst parents to prevent head injuries and death. Methods: This is a cross-sectional study, done by online survey using a snowball sampling technique, the number of included responses were 386 parents (Male and female) living in Riyadh Aged 21 - 60 years old or above. Results: The study showed that there is a difference in Parents’ belief in the importance of helmet use while riding a Bicycle vs Motorcycle/Quad bike and that was affected by parents’ education level, almost all the people who answered the survey (76.7%) agree that it is important for their children to wear a helmet when riding both a Bicycle and a Motorcycle or Quadbike with a cumulative percentage of (93.8%). And almost all agreed on multiple approaches to help increase helmet use be it by forcing rental shops to give out helmets, forcing sellers to recommend the use of helmets, increasing awareness campaigns, and imposing fines for not wearing helmets. Conclusions: This study is the first to explore Family helmet use while riding Bicycles and Motorcycles/Quad bikes. Although Parent’s belief in the importance of helmet use for their children was high, it is clear that the level of practice is low. With that the risk of head injuries might be high, our findings suggest that safety interventions for increasing pediatric helmet use are needed to increase helmet use and reduce the risk of head injury and hospitalization.展开更多
文摘为解析建成环境对共享单车不同时段借还车量的非线性作用,本文以2016年上海摩拜共享单车和网络公开数据为基础,利用梯度提升决策树,建立共享单车工作日,非工作日及工作日早、晚高峰借还车量模型。研究结果显示:变量影响程度方面,街道至市中心距离对4个时段共享单车借还车量具有稳定且突出的作用,相对重要度超过17%;路网密度、非机动车道占比、人口密度影响次之,但在4个时段作用波动较大。非线性关系方面,街道至市中心距离、非机动车道占比、人口密度、就业POI(Point of Interest)密度与各时段共享单车借还车量呈复杂非线性关系,阈值效应显著;路网密度、住宅POI密度则与之总体负相关和正相关。同时段下,建成环境对早晚高峰时期的共享单车借还车量非线性作用差异明显,与高峰时期单车骑行的潮汐性特征相一致,非机动占比与街道中心邻近度、就业POI密度对高峰时段单车骑行作用有明显的协作性作用。
文摘共享单车调配是优化城市交通资源配置的重要手段,但目前的最优路径调配方法往往对单车系统规模敏感。为此,研究一种分时段、区域间调配的共享单车投放方法,提出了带约束的游牧算法(nomad algorithm with constraints,NCA)求解调配模型的最优解。将单车调配问题建模为以单车流量为约束、以最小化运营损耗为目标的优化问题;提出求解上述模型的NCA算法,预测投放区域单车存量和区域间转移量,相比无约束的原游牧算法,改进了局部搜索和全局寻优策略,优化了部落初定位方法;基于预测的存量和转移量得出分时段区域间单车的调配方案。在上海和纽约相关数据集上的对比实验结果表明,运行时长约为其他方法的15%,租赁需求响应率高于分支定界算法0.15%,单车总数和运营损耗比遗传算法降低了约10%,验证了该方法具有更高的优化效率和用户需求响应率。
文摘自行车设定(Bike Fitting)是指利用运动生物力学、人体工程学等知识去分析自行车各个部件最匹配骑行者的设定参数,再使用相关工具去调试或优化自行车,主要涉及鞍座高度、鞍座位置角度、鞍座形状、车把和车架、曲柄长度以及脚踏6个方面。适配的自行车设定能有效预防长期骑行中出现的非创伤性运动损伤并提升运动表现。本研究通过对中国知网、Web of Science和PubMed数据库中国内外有关自行车设定对骑行影响的研究进行综述和评价,让更多专业教练、科研人员以及运动员等从业者了解并重视这方面的知识,为减少骑行导致的运动损伤和提升运动员骑行表现提供借鉴和指导。
文摘Bicycling constitutes an integral component of sustainable non-motorized means of travel. Despite the immense benefits of bicycling, the modal share of bicycling is quite low, specifically among young and low-income commuters e.g., college and university students. This study explores the perceptions of and barriers to bicycling of the campus community at the University of Tennessee, Knoxville with the aim to identify the factors that could enhance bike use among students at the university campus as well as highlight the barriers that keep young population away from biking. An online survey about bike use at the university campus was administered and responses to the survey were recorded. On the methodological front, a binary logit model was estimated with students’ willingness to use bikes at campus as the dependent variable. The survey results revealed that about 47% of the students considered vehicular traffic as the reason for feeling unsafe while biking and emphasized having separate bike routes. Most of the respondents highlighted the need to change clothes after biking in summer or carry things as the reason for not selecting bikes as a mode of transport at the campus, whereas inadequate bike lanes, paths, or trails, insufficient lighting along bike routes, and the lack of adequate bicycle parking were highlighted as the major barriers deterring bike use within the campus. The study suggests development of a campus bike network with proper bike lanes, bike runnels, installation of safety cameras and better lighting at the campus, and bike-supporting infrastructure such as communal showers to be provided in campus buildings to encourage bike use among university students. The study findings can assist campus transportation planners in devising a sustainable campus transportation plan incorporating the influencing factors and deterrents of bike use in a university campus setting.
文摘Objectives: The primary objective was to characterize the range of Knowledge, Attitude, and Practice (KAP) of Helmet use in children amongst parents to prevent head injuries and death. Methods: This is a cross-sectional study, done by online survey using a snowball sampling technique, the number of included responses were 386 parents (Male and female) living in Riyadh Aged 21 - 60 years old or above. Results: The study showed that there is a difference in Parents’ belief in the importance of helmet use while riding a Bicycle vs Motorcycle/Quad bike and that was affected by parents’ education level, almost all the people who answered the survey (76.7%) agree that it is important for their children to wear a helmet when riding both a Bicycle and a Motorcycle or Quadbike with a cumulative percentage of (93.8%). And almost all agreed on multiple approaches to help increase helmet use be it by forcing rental shops to give out helmets, forcing sellers to recommend the use of helmets, increasing awareness campaigns, and imposing fines for not wearing helmets. Conclusions: This study is the first to explore Family helmet use while riding Bicycles and Motorcycles/Quad bikes. Although Parent’s belief in the importance of helmet use for their children was high, it is clear that the level of practice is low. With that the risk of head injuries might be high, our findings suggest that safety interventions for increasing pediatric helmet use are needed to increase helmet use and reduce the risk of head injury and hospitalization.
