The need to simultaneously balance security and fairness in quantum key agreement(QKA) makes it challenging to design a flawless QKA protocol, especially a multiparty quantum key agreement(MQKA) protocol. When designi...The need to simultaneously balance security and fairness in quantum key agreement(QKA) makes it challenging to design a flawless QKA protocol, especially a multiparty quantum key agreement(MQKA) protocol. When designing an MQKA protocol,two modes can be used to transmit the quantum information carriers: travelling mode and distributed mode. MQKA protocols usually have a higher qubit efficiency in travelling mode than in distributed mode. Thus, several travelling mode MQKA protocols have been proposed. However, almost all of these are vulnerable to collusion attacks from internal betrayers. This paper proposes an improved MQKA protocol that operates in travelling mode with Einstein-Podolsky-Rosen pairs. More importantly, we present a new travelling mode MQKA protocol that uses single photons, which is more feasible than previous methods under current technologies.展开更多
The effects of socio-demographics, land use characteristics and trip attributes on the commute mode choice are studied with a nested logit (NL) model. Based on the random utility maximum theory, the NL model is form...The effects of socio-demographics, land use characteristics and trip attributes on the commute mode choice are studied with a nested logit (NL) model. Based on the random utility maximum theory, the NL model is formulated. The analysis is carried out in the main area of Nanjing. Direct and cross elasticities are calculated to analyze the effects of travel time and travel cost on the selection of travel mode choice. The results reveal that the non-motorized travel modes are more attractive in the areas with higher housing and employment accessibility and car owners are found to be more likely to commute to work by car. The bus and subway choice probabilities are more sensitive to changes in travel times than to changes in travel costs. In conclusion, a comprehensive public transit system and effective integration of land use and transportation policies help to relieve the traffic congestion levels caused by the increasing urban sprawl.展开更多
Metropolitan cities in China are commonly confronted with unresolved traffic congestion issues, primarily due to rapidly increasing traffic demand. Group disparity between commuting mode choice and its spatial distrib...Metropolitan cities in China are commonly confronted with unresolved traffic congestion issues, primarily due to rapidly increasing traffic demand. Group disparity between commuting mode choice and its spatial distribution on road networks has enabled us to examine the factors that give rise to the discrepancies and the fundamental spatial causes of traffic congestion. In recent years, mi- cro-perspective, individual, and behavior-based spatial analysis have mushroomed and been facilitated with effective tools such as tem- poral geographic information systems (T-GIS). It is difficult to study the interrelations between transport and space on the basis of commuting mode choice since the mode choice data are invisible in a specific space such as a particular road network. Therefore, in the field of transport, the classical origin destination (OD) four-stage model (FSM) is usually employed to calculate data when studying commuting mode choice. Based on the relative principles of T-GIS and the platform of ArcGIS, this paper considers Guangzhou as a case study and develops a spatio-temporal tool to examine the daily activities of residents. Meanwhile, the traffic volume distribution in rush hours, which was analyzed according to commuting modes and how they were reflected in the road network, was scrutinized with data extracted from travel diaries. Moreover, efforts were made to explain the relationship between traffic demand and urban spatial structure. Based on the investigation, this research indicates that traffic volumes in divergent groups and on the road networks is driven by: l) the socio-economie characteristics of travelers; 2) a jobs-housing imbalance under suburbanization; 3) differences in the spatial supply of transport modes; 4) the remains of the Danwei (work unit) system and market development in China; and 5) the transition of urban spatial structure and other factors.展开更多
In recent years,there have been important developments in the joint analysis of the travel behavior based on discrete choice models as well as in the formulation of increasingly flexible closed-form models belonging t...In recent years,there have been important developments in the joint analysis of the travel behavior based on discrete choice models as well as in the formulation of increasingly flexible closed-form models belonging to the generalized extreme value class.The objective of this work is to describe the simultaneous choice of shopping destination and travel-to-shop mode in downtown area by making use of the cross-nested logit(CNL) structure that allows for potential spatial correlation.The analysis uses data collected in the downtown areas of Maryland-Washington,D.C.region for shopping trips,considering household,individual,land use,and travel-related characteristics.The estimation results show that the dissimilarity parameter in the CNL model is 0.37 and significant at the 95% level,indicating that the alternatives have high spatial correlation for the short shopping distance.The results of analysis reveal detailed significant influences on travel behavior of joint choice shopping destination and travel mode.Moreover,a Monte Carlo simulation for a group of scenarios arising from transportation policies and parking fees in downtown area,was undertaken to examine the impact of a change in car travel cost on the shopping destination and travel mode switching.These findings have important implications for transportation demand management and urban planning.展开更多
This research presents an analysis of travel mode choice for trips to Ho Chi Minh City metro station. Research methods were inherited through a formula to calculate passenger traffic forecasts to predict passengers, g...This research presents an analysis of travel mode choice for trips to Ho Chi Minh City metro station. Research methods were inherited through a formula to calculate passenger traffic forecasts to predict passengers, going to the station. Based on the collected data of interviews, traffic surveys, and "Irwin & Von Cube" function, forecast the proportion of travel mode, and use to go to the station and leaving from the station. The results of study are used for the purpose of calculating the size of the metro station parking lots and parking layout plan.展开更多
The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of ...The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area.With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington-Baltimore Household Travel Survey in 2007,including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors.This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.展开更多
This paper aims to compare the results of two techniques of Kriging (Ordinary Kriging and Indicator Kriging) that are applied to estimate the Private Motorized (PM) travel mode use (car or motorcycle) in several geogr...This paper aims to compare the results of two techniques of Kriging (Ordinary Kriging and Indicator Kriging) that are applied to estimate the Private Motorized (PM) travel mode use (car or motorcycle) in several geographical coordinates of non-sampled values of the concerning variable. The data used was from the Origin/Destination and Public Transportation Opinion Survey, carried out in 2007/2008 at S?o Carlos (SP, Brazil). The techniques were applied in the region with 110 sample points (households). Initially, Decision Tree was applied to estimate the probability of mode choice in surveyed households, thus determining the numeric variable to be used in Ordinary Kriging. For application of Indicator Kriging it was used the variable “main travel mode” in a discrete manner, where “1” represented the use of PM travel mode and “0” characterized others travel modes. The results obtained by the two spatial estimation techniques were similar (Kriging maps and cross-validation procedure). However, the Indicator Kriging (KI) obtained the highest number of hit rates. In addition, with the KI it was possible to use the variable in its original form, avoiding error propagation. Finally, it was concluded that spatial statistics was thriving in travel demand forecasting issues, giving rise, for the both Kriging methods, to a travel mode choice surface on a confirmatory way.展开更多
In the travel process of urban residents,travelers will take a series of activities such as imitation and exclusion by observing other people’s travel modes,which affects their following trips.This process can be see...In the travel process of urban residents,travelers will take a series of activities such as imitation and exclusion by observing other people’s travel modes,which affects their following trips.This process can be seen as a repeated game between members of the travelers.Based on the analysis of this game and its evolution trend,a multi-dimensional game model of low-carbon travel for residents is established.The two dimensional game strategies include whether to accept the low-carbon concept and whether to choose low-carbon travel.Combined with evolutionary game theory,the low-carbon travel choices of residents in different cities are simulated,and the evolutionary stability strategies are obtained.Finally,the influences of the main parameters of the model on the evolution process and stability strategies are discussed.The results show that travelers would develop towards two trends.Cities with more developed public traffic system have a higher proportion of receiving low-carbon concept and choosing low-carbon travel.Cities with underdeveloped public transport system could increase this proportion by some measures such as encouraging residents to choose slow transport and increasing the propaganda of low-carbon travel,but the positive effects of the measures like propaganda have a limited impact on the proportion.展开更多
Urban air mobility(UAM)is an emerging concept proposed in recent years that uses electric vertical takeoff and landing vehicles(eVTOLs).UAM is expected to offer an alternative way of transporting passengers and goods ...Urban air mobility(UAM)is an emerging concept proposed in recent years that uses electric vertical takeoff and landing vehicles(eVTOLs).UAM is expected to offer an alternative way of transporting passengers and goods in urban areas with significantly improved mobility by making use of low-altitude airspace.In addition to other essential elements,ground infrastructure of vertiports is needed to transition UAM from concept to operation.This study examines the network design of UAM on-demand service,with a particular focus on the use of integer programming and a solution algorithm to determine the optimal locations of vertiports,user allocation to vertiports,and vertiport access-and egress-mode choices while considering the interactions between vertiport locations and potential UAM travel demand.A case study based on simulated disaggregate travel demand data of the Tampa Bay area in Florida,USA was conducted to demonstrate the effectiveness of the proposed model.Candidate vertiport locations were obtained by analyzing a three-dimensional(3D)geographic information system(GIS)map developed from lidar data of Florida and physical and regulation constraints of eVTOL operations at vertiports.Optimal locations of vertiports were determined to achieve the minimal total generalized cost;however,the modeling structure allows each user to select a better mode between ground transportation and UAM in terms of generalized cost.The outcomes of the case study reveal that although the percentage of trips that switched from ground mode to multimodal UAM was small,users choosing the UAM service benefited from significant time saving.In addition,the impact of different parameter settings on the demand for UAM service was explored from the supply side,and different pricing strategies were tested that might influence potential demand and revenue generation for UAM operators.The combined effects of the number of vertiports and pricing strategies were also analyzed.The findings from this study offer in-depth planning and managerial insights for municipal decision-makers and UAM operators.The conclusion of this paper discusses caveats to the study,ongoing efforts by the authors,and future directions in UAM research.展开更多
In the metropolises of China, the metro plays an increasingly important role in commuting because of its efficiency, affordability, and cleanliness. This paper attempts to explore the relationship between walking acce...In the metropolises of China, the metro plays an increasingly important role in commuting because of its efficiency, affordability, and cleanliness. This paper attempts to explore the relationship between walking access distance to metro stations and the demographic characteristics of passengers, such as age, monthly income, travel frequency, gender, and travel purpose, as well as the influence of the urban context. Nanjing Metro Line 2 is selected as the case study. By using different methods such as a questionnaire survey, spatial decay function, analysis of covariance(ANOVA), network analysis of routes, and K-means cluster analysis, it is suggested that demographic characteristics have a significant impact on the pedestrian walking distance, with the exception of gender. Furthermore, the paper finds a spatial decay effect in walking access distance, the decay rate of which, however, varies across stations. Terminal stations have a larger pedestrian catchment area than in regular and exchange stations. Moreover, the passengers of Nanjing Metro Line 2 can be classified into six groups according to their demographic characteristics, among which education and occupation are vital indicators in determining their willingness to walk to the stations. Middle-class passengers have a higher dependence on the metro and tend to walk longer than other groups do. This study provides an important reference for planners and transport sectors to optimize land-use and transport infrastructures.展开更多
In this study, we investigate travel mode choice behavior between taxi and subway with an emphasis on the influence of traveling convenience. In the first stage, we examine the Origin-Destination(OD) points of Beijing...In this study, we investigate travel mode choice behavior between taxi and subway with an emphasis on the influence of traveling convenience. In the first stage, we examine the Origin-Destination(OD) points of Beijing taxi trips and compare these locations with the respective nearest subway station. Statistics reveal several interesting conclusions. First, for approximately 24.89% of all trips, no convenient subway connections exist between the OD pairs. As such, a taxi becomes the only viable choice. Second, for 80.23% of the remaining 75.11%of trips(equivalent to 60.26% of all trips), access distance from either the origin or the destination to the nearest subway station is greater than 500 meters. This phenomenon indicates that walking distance plays an important role in travel mode choice. In the second stage, we examine groups of taxi trips with similar travel distances and travel times to reveal common features. We establish a preference rule in terms of travel distance and travel time.This determines whether an individual driver will take a taxi or the subway, using a pairwise comparison-based preference regression model. Tests indicate that more than 95% of taxi trips can be correctly predicted by this preference rule. This conclusion reveals that traveling convenience dominates the travel model choice between taxi and subway. All these findings shed light on the factors that influence travel mode choice behavior.展开更多
Based on research of the current situation and analysis result of a case study in the Nanjing region, this paper proposes a "whee(chair slow transit"(WST) system-based elderly auxiliary travel mode. The system in...Based on research of the current situation and analysis result of a case study in the Nanjing region, this paper proposes a "whee(chair slow transit"(WST) system-based elderly auxiliary travel mode. The system involves three fundamental composition frames, namely, support, transit components, and connection components. Each component is designed as an armrest, ground track, or vertical type to respond to actual demands. Thus, this system may be adaptable to diverse conditions. Taking Xiangpuying community as a case study, the author examined the application of the WST auxi(iary mode in particular communities. The WST system helps to increase the accessibility of existing public areas, creates a safe community traffic environment, improves municipal facilities, and strengthens universal design. The study intends to provide a reference to obtain a complete aged care design and to build a comfortable and livable aged care community environment.展开更多
According to Kirchhoff-Love's assumptions, this paper establishes linear system of equations for solving eigen frequency constant and corresponding mode shape. Using engineer-ing and numerical analysis software Ma...According to Kirchhoff-Love's assumptions, this paper establishes linear system of equations for solving eigen frequency constant and corresponding mode shape. Using engineer-ing and numerical analysis software Matlab5.2 and method of coefficient determinant searching arithmetic, eigen frequency constant and mode shape of the stator with i.d./ o.d. ratio of 0.1, 0.3, 0.35, 0.6 and different vibration modes are accurately solved and analyzed. By means of Newton interpolation method, contributions of transverse deflection amplitude and vibration energy corresponding to various modes are determined. This paper offers a valid theoretical foundation for the optimum design of the stator of disk-shaped ultrasonic motors. Furthermore, according to results of numerical analysis, several choosing principles of vibration modes are summarized.展开更多
Amidst the rapid urbanization in the country,the importance of urban public transport has been realized by the governments.Public transport is vital to the city's economy and ensures social equity.Bus Rapid Transi...Amidst the rapid urbanization in the country,the importance of urban public transport has been realized by the governments.Public transport is vital to the city's economy and ensures social equity.Bus Rapid Transit System(BRTS)has emerged as an exciting way to decongest the cities,enhancing and increasing mobility and accessi-bility and promoting transit-oriented development.India's longest BRTS,Janmarg,was created with similar ob-jectives.However,the system faces reduced ridership and inhibited growth because of its hidden inefficiencies.This research aims to identify all the factors affecting ridership,accessibility,and inhibiting the system's growth even after having sufficient infrastructure.It also aims to quantitatively determine whether Janmarg could achieve its establishment's objectives on the city transportation system after thirteen years of the successful implementation of the project.The research methodology used in this work combines primary and secondary research.The factors are responsible for preventing Janmarg from achieving its objectives and utilizing its full potential are determined and recommended ways to utilize adversities effectively.Results show that this study endorses reducing ambiguities and a way forward for making a sustainable transportation system.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.61501414,61602045,61601171,61309029,11504024 and 61502041)
文摘The need to simultaneously balance security and fairness in quantum key agreement(QKA) makes it challenging to design a flawless QKA protocol, especially a multiparty quantum key agreement(MQKA) protocol. When designing an MQKA protocol,two modes can be used to transmit the quantum information carriers: travelling mode and distributed mode. MQKA protocols usually have a higher qubit efficiency in travelling mode than in distributed mode. Thus, several travelling mode MQKA protocols have been proposed. However, almost all of these are vulnerable to collusion attacks from internal betrayers. This paper proposes an improved MQKA protocol that operates in travelling mode with Einstein-Podolsky-Rosen pairs. More importantly, we present a new travelling mode MQKA protocol that uses single photons, which is more feasible than previous methods under current technologies.
基金The National Natural Science Foundation of China(No.50908051)
文摘The effects of socio-demographics, land use characteristics and trip attributes on the commute mode choice are studied with a nested logit (NL) model. Based on the random utility maximum theory, the NL model is formulated. The analysis is carried out in the main area of Nanjing. Direct and cross elasticities are calculated to analyze the effects of travel time and travel cost on the selection of travel mode choice. The results reveal that the non-motorized travel modes are more attractive in the areas with higher housing and employment accessibility and car owners are found to be more likely to commute to work by car. The bus and subway choice probabilities are more sensitive to changes in travel times than to changes in travel costs. In conclusion, a comprehensive public transit system and effective integration of land use and transportation policies help to relieve the traffic congestion levels caused by the increasing urban sprawl.
基金Under the auspices of National Natural Science Foundation of China(No.40971098)National High Technology Research and Development Program of China(No.2012AA121402)
文摘Metropolitan cities in China are commonly confronted with unresolved traffic congestion issues, primarily due to rapidly increasing traffic demand. Group disparity between commuting mode choice and its spatial distribution on road networks has enabled us to examine the factors that give rise to the discrepancies and the fundamental spatial causes of traffic congestion. In recent years, mi- cro-perspective, individual, and behavior-based spatial analysis have mushroomed and been facilitated with effective tools such as tem- poral geographic information systems (T-GIS). It is difficult to study the interrelations between transport and space on the basis of commuting mode choice since the mode choice data are invisible in a specific space such as a particular road network. Therefore, in the field of transport, the classical origin destination (OD) four-stage model (FSM) is usually employed to calculate data when studying commuting mode choice. Based on the relative principles of T-GIS and the platform of ArcGIS, this paper considers Guangzhou as a case study and develops a spatio-temporal tool to examine the daily activities of residents. Meanwhile, the traffic volume distribution in rush hours, which was analyzed according to commuting modes and how they were reflected in the road network, was scrutinized with data extracted from travel diaries. Moreover, efforts were made to explain the relationship between traffic demand and urban spatial structure. Based on the investigation, this research indicates that traffic volumes in divergent groups and on the road networks is driven by: l) the socio-economie characteristics of travelers; 2) a jobs-housing imbalance under suburbanization; 3) differences in the spatial supply of transport modes; 4) the remains of the Danwei (work unit) system and market development in China; and 5) the transition of urban spatial structure and other factors.
基金Projects(JCYJ20120615145601342,JCYJ20130325151523015)supported by Shenzhen Science and Technology Development Funding-Fundamental Research Plan,ChinaProject(2013U-6)supported by Key Laboratory of Eco Planning & Green Building,Ministry of Education(Tsinghua University),China
文摘In recent years,there have been important developments in the joint analysis of the travel behavior based on discrete choice models as well as in the formulation of increasingly flexible closed-form models belonging to the generalized extreme value class.The objective of this work is to describe the simultaneous choice of shopping destination and travel-to-shop mode in downtown area by making use of the cross-nested logit(CNL) structure that allows for potential spatial correlation.The analysis uses data collected in the downtown areas of Maryland-Washington,D.C.region for shopping trips,considering household,individual,land use,and travel-related characteristics.The estimation results show that the dissimilarity parameter in the CNL model is 0.37 and significant at the 95% level,indicating that the alternatives have high spatial correlation for the short shopping distance.The results of analysis reveal detailed significant influences on travel behavior of joint choice shopping destination and travel mode.Moreover,a Monte Carlo simulation for a group of scenarios arising from transportation policies and parking fees in downtown area,was undertaken to examine the impact of a change in car travel cost on the shopping destination and travel mode switching.These findings have important implications for transportation demand management and urban planning.
文摘This research presents an analysis of travel mode choice for trips to Ho Chi Minh City metro station. Research methods were inherited through a formula to calculate passenger traffic forecasts to predict passengers, going to the station. Based on the collected data of interviews, traffic surveys, and "Irwin & Von Cube" function, forecast the proportion of travel mode, and use to go to the station and leaving from the station. The results of study are used for the purpose of calculating the size of the metro station parking lots and parking layout plan.
基金Project(71173061)supported by the National Natural Science Foundation of ChinaProject(2013U-6)supported by Key Laboratory of Eco Planning & Green Building,Ministry of Education(Tsinghua University),China
文摘The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area.With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington-Baltimore Household Travel Survey in 2007,including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors.This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.
文摘This paper aims to compare the results of two techniques of Kriging (Ordinary Kriging and Indicator Kriging) that are applied to estimate the Private Motorized (PM) travel mode use (car or motorcycle) in several geographical coordinates of non-sampled values of the concerning variable. The data used was from the Origin/Destination and Public Transportation Opinion Survey, carried out in 2007/2008 at S?o Carlos (SP, Brazil). The techniques were applied in the region with 110 sample points (households). Initially, Decision Tree was applied to estimate the probability of mode choice in surveyed households, thus determining the numeric variable to be used in Ordinary Kriging. For application of Indicator Kriging it was used the variable “main travel mode” in a discrete manner, where “1” represented the use of PM travel mode and “0” characterized others travel modes. The results obtained by the two spatial estimation techniques were similar (Kriging maps and cross-validation procedure). However, the Indicator Kriging (KI) obtained the highest number of hit rates. In addition, with the KI it was possible to use the variable in its original form, avoiding error propagation. Finally, it was concluded that spatial statistics was thriving in travel demand forecasting issues, giving rise, for the both Kriging methods, to a travel mode choice surface on a confirmatory way.
基金Project(BK20160512)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(16YJCZH027)supported by the Humanity and Social Science Youth Foundation of Ministry of Education of ChinaProject(15GLC004)supported by the Social Science Foundation of Jiangsu Province,China
文摘In the travel process of urban residents,travelers will take a series of activities such as imitation and exclusion by observing other people’s travel modes,which affects their following trips.This process can be seen as a repeated game between members of the travelers.Based on the analysis of this game and its evolution trend,a multi-dimensional game model of low-carbon travel for residents is established.The two dimensional game strategies include whether to accept the low-carbon concept and whether to choose low-carbon travel.Combined with evolutionary game theory,the low-carbon travel choices of residents in different cities are simulated,and the evolutionary stability strategies are obtained.Finally,the influences of the main parameters of the model on the evolution process and stability strategies are discussed.The results show that travelers would develop towards two trends.Cities with more developed public traffic system have a higher proportion of receiving low-carbon concept and choosing low-carbon travel.Cities with underdeveloped public transport system could increase this proportion by some measures such as encouraging residents to choose slow transport and increasing the propaganda of low-carbon travel,but the positive effects of the measures like propaganda have a limited impact on the proportion.
文摘Urban air mobility(UAM)is an emerging concept proposed in recent years that uses electric vertical takeoff and landing vehicles(eVTOLs).UAM is expected to offer an alternative way of transporting passengers and goods in urban areas with significantly improved mobility by making use of low-altitude airspace.In addition to other essential elements,ground infrastructure of vertiports is needed to transition UAM from concept to operation.This study examines the network design of UAM on-demand service,with a particular focus on the use of integer programming and a solution algorithm to determine the optimal locations of vertiports,user allocation to vertiports,and vertiport access-and egress-mode choices while considering the interactions between vertiport locations and potential UAM travel demand.A case study based on simulated disaggregate travel demand data of the Tampa Bay area in Florida,USA was conducted to demonstrate the effectiveness of the proposed model.Candidate vertiport locations were obtained by analyzing a three-dimensional(3D)geographic information system(GIS)map developed from lidar data of Florida and physical and regulation constraints of eVTOL operations at vertiports.Optimal locations of vertiports were determined to achieve the minimal total generalized cost;however,the modeling structure allows each user to select a better mode between ground transportation and UAM in terms of generalized cost.The outcomes of the case study reveal that although the percentage of trips that switched from ground mode to multimodal UAM was small,users choosing the UAM service benefited from significant time saving.In addition,the impact of different parameter settings on the demand for UAM service was explored from the supply side,and different pricing strategies were tested that might influence potential demand and revenue generation for UAM operators.The combined effects of the number of vertiports and pricing strategies were also analyzed.The findings from this study offer in-depth planning and managerial insights for municipal decision-makers and UAM operators.The conclusion of this paper discusses caveats to the study,ongoing efforts by the authors,and future directions in UAM research.
基金Under the auspices of National Nature Science Foundation of China(No.41701180)
文摘In the metropolises of China, the metro plays an increasingly important role in commuting because of its efficiency, affordability, and cleanliness. This paper attempts to explore the relationship between walking access distance to metro stations and the demographic characteristics of passengers, such as age, monthly income, travel frequency, gender, and travel purpose, as well as the influence of the urban context. Nanjing Metro Line 2 is selected as the case study. By using different methods such as a questionnaire survey, spatial decay function, analysis of covariance(ANOVA), network analysis of routes, and K-means cluster analysis, it is suggested that demographic characteristics have a significant impact on the pedestrian walking distance, with the exception of gender. Furthermore, the paper finds a spatial decay effect in walking access distance, the decay rate of which, however, varies across stations. Terminal stations have a larger pedestrian catchment area than in regular and exchange stations. Moreover, the passengers of Nanjing Metro Line 2 can be classified into six groups according to their demographic characteristics, among which education and occupation are vital indicators in determining their willingness to walk to the stations. Middle-class passengers have a higher dependence on the metro and tend to walk longer than other groups do. This study provides an important reference for planners and transport sectors to optimize land-use and transport infrastructures.
基金supported in part by the National Natural Science Foundation of China (Nos. 61603005 and 61503007)the Beijing Municipal Science and Technology Project (No. D171100000317002)
文摘In this study, we investigate travel mode choice behavior between taxi and subway with an emphasis on the influence of traveling convenience. In the first stage, we examine the Origin-Destination(OD) points of Beijing taxi trips and compare these locations with the respective nearest subway station. Statistics reveal several interesting conclusions. First, for approximately 24.89% of all trips, no convenient subway connections exist between the OD pairs. As such, a taxi becomes the only viable choice. Second, for 80.23% of the remaining 75.11%of trips(equivalent to 60.26% of all trips), access distance from either the origin or the destination to the nearest subway station is greater than 500 meters. This phenomenon indicates that walking distance plays an important role in travel mode choice. In the second stage, we examine groups of taxi trips with similar travel distances and travel times to reveal common features. We establish a preference rule in terms of travel distance and travel time.This determines whether an individual driver will take a taxi or the subway, using a pairwise comparison-based preference regression model. Tests indicate that more than 95% of taxi trips can be correctly predicted by this preference rule. This conclusion reveals that traveling convenience dominates the travel model choice between taxi and subway. All these findings shed light on the factors that influence travel mode choice behavior.
基金Financial support for this work has been provided by the National Natural Science Foundation of China (Grant no. 51178095).
文摘Based on research of the current situation and analysis result of a case study in the Nanjing region, this paper proposes a "whee(chair slow transit"(WST) system-based elderly auxiliary travel mode. The system involves three fundamental composition frames, namely, support, transit components, and connection components. Each component is designed as an armrest, ground track, or vertical type to respond to actual demands. Thus, this system may be adaptable to diverse conditions. Taking Xiangpuying community as a case study, the author examined the application of the WST auxi(iary mode in particular communities. The WST system helps to increase the accessibility of existing public areas, creates a safe community traffic environment, improves municipal facilities, and strengthens universal design. The study intends to provide a reference to obtain a complete aged care design and to build a comfortable and livable aged care community environment.
文摘According to Kirchhoff-Love's assumptions, this paper establishes linear system of equations for solving eigen frequency constant and corresponding mode shape. Using engineer-ing and numerical analysis software Matlab5.2 and method of coefficient determinant searching arithmetic, eigen frequency constant and mode shape of the stator with i.d./ o.d. ratio of 0.1, 0.3, 0.35, 0.6 and different vibration modes are accurately solved and analyzed. By means of Newton interpolation method, contributions of transverse deflection amplitude and vibration energy corresponding to various modes are determined. This paper offers a valid theoretical foundation for the optimum design of the stator of disk-shaped ultrasonic motors. Furthermore, according to results of numerical analysis, several choosing principles of vibration modes are summarized.
文摘Amidst the rapid urbanization in the country,the importance of urban public transport has been realized by the governments.Public transport is vital to the city's economy and ensures social equity.Bus Rapid Transit System(BRTS)has emerged as an exciting way to decongest the cities,enhancing and increasing mobility and accessi-bility and promoting transit-oriented development.India's longest BRTS,Janmarg,was created with similar ob-jectives.However,the system faces reduced ridership and inhibited growth because of its hidden inefficiencies.This research aims to identify all the factors affecting ridership,accessibility,and inhibiting the system's growth even after having sufficient infrastructure.It also aims to quantitatively determine whether Janmarg could achieve its establishment's objectives on the city transportation system after thirteen years of the successful implementation of the project.The research methodology used in this work combines primary and secondary research.The factors are responsible for preventing Janmarg from achieving its objectives and utilizing its full potential are determined and recommended ways to utilize adversities effectively.Results show that this study endorses reducing ambiguities and a way forward for making a sustainable transportation system.