The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers b...The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers both bus network design and public bicycle network design is proposed. The chemical reaction optimization(CRO) is designed to solve the problem. A shortcoming of CRO is that, when the two-molecule collisions take place, the molecules are randomly picked from the container.Hence, we improve CRO by employing different mating strategies. The computational results confirm the benefits of the mating strategies. Numerical experiments are conducted on the Sioux-Falls network. A comparison with the traditional sequential modeling framework indicates that the proposed approach has a better performance and is more robust. The practical applicability of the approach is proved by employing a real size network.展开更多
Public bicycle service has experienced 15 years of development in Chinese cities,and China's Mainland is the world's largest public bicycle market.Choosing to use public bicycles is becoming more and more a da...Public bicycle service has experienced 15 years of development in Chinese cities,and China's Mainland is the world's largest public bicycle market.Choosing to use public bicycles is becoming more and more a daily habit of residents.Broadly speaking,public bicycles in Chinese cities include both public bikes with service stations and shared bicycles without service stations.Based on historical review and years of accumulated data,this paper reviews the development of general public bicycles in Chinese cities in the past 15 years.And the role of general public bicycles in China’s urban transportation system is analyzed.Finally,from the perspective of urban construction and management,some suggestions for the future development of public bicycles are put forward.展开更多
大气中的^(210)Pb与^(210)Po,主要来自地表土壤氡的衰变,是铀系最后两个长寿命子体。为测量大气^(210)Pb与^(210)Po水平,研究建立了以206Pb为载体、离子交换为分离手段的^(210)Pb方法,以及以209Po为示踪剂加α能谱的^(210)Po方法。运用...大气中的^(210)Pb与^(210)Po,主要来自地表土壤氡的衰变,是铀系最后两个长寿命子体。为测量大气^(210)Pb与^(210)Po水平,研究建立了以206Pb为载体、离子交换为分离手段的^(210)Pb方法,以及以209Po为示踪剂加α能谱的^(210)Po方法。运用所建立的分析方法,对杭州地区开展了大气气溶胶^(210)Pb与^(210)Po水平分析。2012年连续监测结果表明,杭州地区大气^(210)Pb年平均水平为(1.31±0.69)m Bq/m^3,范围为0.12~2.74 m Bq/m^3;^(210)Po年平均水平为(0.29±0.18)m Bq/m^3,范围为0.06~0.89 m Bq/m^3。杭州地区大气^(210)Pb与^(210)Po水平与国内其它城市较为一致,比欧美约偏高一个量级。根据监测结果,对大气^(210)Pb与^(210)Po以吸入方式所致公众待积有效剂量作了初步估算,公众剂量水平为1.5~13.8μSv/a,平均剂量为7.0μSv/a。展开更多
为分析建成环境对公共自行车出行模式的影响,文章结合公共自行车运营数据和建成环境数据,以公共自行车站点为中心建立缓冲区并提取缓冲区内兴趣点(point of interest,POI),在考虑POI规模的基础上划分站点类型;根据站点类型对出行起讫点(...为分析建成环境对公共自行车出行模式的影响,文章结合公共自行车运营数据和建成环境数据,以公共自行车站点为中心建立缓冲区并提取缓冲区内兴趣点(point of interest,POI),在考虑POI规模的基础上划分站点类型;根据站点类型对出行起讫点(origin-destination,OD)分类,以OD类型确定公共自行车出行模式,使用地理加权回归(geographically weighted regression,GWR)模型,分析建成环境对公共自行车出行模式的影响;以昆明市为例进行实证分析。结果表明:昆明市公共自行车出行模式可划分为16种,OD皆为住宅主导型和公司(企业)主导型站点的出行模式约占69.26%;建成环境对不同出行模式的影响效应存在差异;土地利用混合度是公共自行车出行模式的主要影响因素。研究结果可为公共自行车布局优化及运营管理提供参考。展开更多
The bad behaviors of some users and the drawbacks of public bicycles have hindered the promotion of public bicycles. The current problems include low utilization rate, uneven distribution, high loss rate and insecure ...The bad behaviors of some users and the drawbacks of public bicycles have hindered the promotion of public bicycles. The current problems include low utilization rate, uneven distribution, high loss rate and insecure lock. However, there is few feasible research in this new field. To address these issues of public bicycles, we propose a public bicycle operating system（PBOS）. PBOS involves three key technologies： 1） To acquire a dynamic password and realize bicycle self-rescue, we devise an intelligent lock that utilizes the Internet of Things（IoT） to establish Bluetooth connection with user＇s mobile phone. 2） To avoid bicycle loss and improve the security of data transmission, we design a space-time security protocol to work between bicycle＇s intelligent lock, mobile app, and server. 3） To increase the average utilization rate and distribution, we present a cooperative game model for bicycle scheduling. Finally, we evaluate the performance and validate the theoretical properties of PBOS through extensive simulations.展开更多
基金Projects(71301115,71271150,71101102)supported by the National Natural Science Foundation of ChinaProject(20130032120009)supported by Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers both bus network design and public bicycle network design is proposed. The chemical reaction optimization(CRO) is designed to solve the problem. A shortcoming of CRO is that, when the two-molecule collisions take place, the molecules are randomly picked from the container.Hence, we improve CRO by employing different mating strategies. The computational results confirm the benefits of the mating strategies. Numerical experiments are conducted on the Sioux-Falls network. A comparison with the traditional sequential modeling framework indicates that the proposed approach has a better performance and is more robust. The practical applicability of the approach is proved by employing a real size network.
基金This work was supported by the Natural Science Foundation of China(51608473)Shanghai philosophy and social science planning project(No.2017ECK004)+1 种基金2017 Zhejiang Provincial Department of Education General Research Project(Natural Science)(Y201738361)USST Innovation and Entrepreneurship Training Program(XJ2019132).
文摘Public bicycle service has experienced 15 years of development in Chinese cities,and China's Mainland is the world's largest public bicycle market.Choosing to use public bicycles is becoming more and more a daily habit of residents.Broadly speaking,public bicycles in Chinese cities include both public bikes with service stations and shared bicycles without service stations.Based on historical review and years of accumulated data,this paper reviews the development of general public bicycles in Chinese cities in the past 15 years.And the role of general public bicycles in China’s urban transportation system is analyzed.Finally,from the perspective of urban construction and management,some suggestions for the future development of public bicycles are put forward.
文摘大气中的^(210)Pb与^(210)Po,主要来自地表土壤氡的衰变,是铀系最后两个长寿命子体。为测量大气^(210)Pb与^(210)Po水平,研究建立了以206Pb为载体、离子交换为分离手段的^(210)Pb方法,以及以209Po为示踪剂加α能谱的^(210)Po方法。运用所建立的分析方法,对杭州地区开展了大气气溶胶^(210)Pb与^(210)Po水平分析。2012年连续监测结果表明,杭州地区大气^(210)Pb年平均水平为(1.31±0.69)m Bq/m^3,范围为0.12~2.74 m Bq/m^3;^(210)Po年平均水平为(0.29±0.18)m Bq/m^3,范围为0.06~0.89 m Bq/m^3。杭州地区大气^(210)Pb与^(210)Po水平与国内其它城市较为一致,比欧美约偏高一个量级。根据监测结果,对大气^(210)Pb与^(210)Po以吸入方式所致公众待积有效剂量作了初步估算,公众剂量水平为1.5~13.8μSv/a,平均剂量为7.0μSv/a。
文摘为分析建成环境对公共自行车出行模式的影响,文章结合公共自行车运营数据和建成环境数据,以公共自行车站点为中心建立缓冲区并提取缓冲区内兴趣点(point of interest,POI),在考虑POI规模的基础上划分站点类型;根据站点类型对出行起讫点(origin-destination,OD)分类,以OD类型确定公共自行车出行模式,使用地理加权回归(geographically weighted regression,GWR)模型,分析建成环境对公共自行车出行模式的影响;以昆明市为例进行实证分析。结果表明:昆明市公共自行车出行模式可划分为16种,OD皆为住宅主导型和公司(企业)主导型站点的出行模式约占69.26%;建成环境对不同出行模式的影响效应存在差异;土地利用混合度是公共自行车出行模式的主要影响因素。研究结果可为公共自行车布局优化及运营管理提供参考。
基金Supported by the National Key Research and Development Program of China(2016YFB0501805)the National Natural Science Foundation of China(61573262)
文摘The bad behaviors of some users and the drawbacks of public bicycles have hindered the promotion of public bicycles. The current problems include low utilization rate, uneven distribution, high loss rate and insecure lock. However, there is few feasible research in this new field. To address these issues of public bicycles, we propose a public bicycle operating system（PBOS）. PBOS involves three key technologies： 1） To acquire a dynamic password and realize bicycle self-rescue, we devise an intelligent lock that utilizes the Internet of Things（IoT） to establish Bluetooth connection with user＇s mobile phone. 2） To avoid bicycle loss and improve the security of data transmission, we design a space-time security protocol to work between bicycle＇s intelligent lock, mobile app, and server. 3） To increase the average utilization rate and distribution, we present a cooperative game model for bicycle scheduling. Finally, we evaluate the performance and validate the theoretical properties of PBOS through extensive simulations.
