Delineating life circles is an essential prerequisite for urban community life circle planning. Recent studies combined the environmental contexts with residents’ global positioning system(GPS) data to delineate the ...Delineating life circles is an essential prerequisite for urban community life circle planning. Recent studies combined the environmental contexts with residents’ global positioning system(GPS) data to delineate the life circles. This method, however, is constrained by GPS data, and it can only be applied in the GPS surveyed communities. To address this limitation, this study developed a generalizable delineation method without the constraint of behavioral data. According to previous research, the community life circle consists of the walking-accessible range and internal structure. The core task to develop the generalizable method was to estimate the spatiotemporal behavioral demand for each plot of land to acquire the internal structure of the life circle, as the range can be delineated primarily based on environmental data. Therefore, behavioral demand estimation models were established through logistic regression and machine learning techniques, including decision trees and ensemble learning. The model with the lowest error rate was chosen as the final estimation model for each type of land. Finally, we used a community without GPS data as an example to demonstrate the effectiveness of the estimation models and delineation method. This article extends the existing literature by introducing spatiotemporal behavioral demand estimation models, which learn the relationships between environmental contexts, population composition and the existing delineated results based on GPS data to delineate the internal structure of the community life circle without employing behavioral data. Furthermore, the proposed method and delineation results also contributes to facilities adjustments and location selections in life circle planning, people-oriented transformation in urban planning, and activity space estimation of the population in evaluating and improving the urban policies.展开更多
Under the macro background of rapid urbanization and social transformation in China,campus space renewal has become an important practice and carrier for the sustainable development of schools.The study on campus spac...Under the macro background of rapid urbanization and social transformation in China,campus space renewal has become an important practice and carrier for the sustainable development of schools.The study on campus space by big data and quantitative reflection of spatial distribution of applicable people in different areas of the campus can provide a certain scientific basis for campus space updating.West campus of Yangtze University is taken as research object.Based on cognitive map method,questionnaire survey method,behavior trajectory and correlation analysis method,the types and characteristics of campus space composition,campus satisfaction,usage and its relevance are analyzed.Research results show that ①the overall imageability of campus space is higher,which has a significantly positive correlation with the satisfaction of campus environment,and has no correlation with users’ behavior activities.The use frequency of non teaching areas varies greatly in different periods of time.②The correlation between the surrounding green vegetation and the image degree of campus landmarks is the most significant,and the coefficient is 0.886.③The correlation between spatial size suitability and regional image degree is the most significant,and the coefficient is 0.937.④The correlation between public activity facilities in the region and node image degree is the most significant,and the coefficient is 0.995.According to the research results,the corresponding solutions are put forward to provide scientific and quantitative reference suggestions for the renewal and transformation of the campus.展开更多
Engineering ultrashort laser pulses is crucial for advancing fundamental research fields and applications.Controlling their spatiotemporal behavior,tailored to specific applications,can unlock new experimental capabil...Engineering ultrashort laser pulses is crucial for advancing fundamental research fields and applications.Controlling their spatiotemporal behavior,tailored to specific applications,can unlock new experimental capabilities.However,achieving this control is particularly challenging due to the difficulty in independently structuring their intensity and spatial phase distributions,given their polychromatic bandwidth.This article addresses this challenge by presenting a technique for generating flying structured laser pulses with tunable spatiotemporal behavior.We developed a comprehensive approach to directly design and govern these laser pulses.This method elucidates the role jointly played by the pulse's spatiotemporal couplings and its prescribed phase gradient in governing the pulse dynamics.It evidences that the often-overlooked design of the phase gradient is indeed essential for achieving programmable spatiotemporal control of the pulses.By tailoring the prescribed phase gradient,we demonstrate the creation of,to our knowledge,novel families of flying structured laser pulses that travel at the speed of light in helical spring and vortex multi-ring forms of different geometries.The achieved control over the dynamics of their intensity peaks and wavefronts is analyzed in detail.For instance,the intensity peak can be configured as a THz rotating light spot or shaped as a curve,enabling simultaneous substrate illumination at rates of tens of THz,far exceeding the MHz rates typically used in laser material processing.Additionally,the independent manipulation of the pulse wavefronts allows local tuning of the orbital angular momentum density carried by the beam.Together,these advancements unveil advantageous capabilities that have been sought after for many years,especially in ultrafast optics and light-matter interaction research.展开更多
基金Under the auspices of the National Natural Science Foundation of China(No.41571144)。
文摘Delineating life circles is an essential prerequisite for urban community life circle planning. Recent studies combined the environmental contexts with residents’ global positioning system(GPS) data to delineate the life circles. This method, however, is constrained by GPS data, and it can only be applied in the GPS surveyed communities. To address this limitation, this study developed a generalizable delineation method without the constraint of behavioral data. According to previous research, the community life circle consists of the walking-accessible range and internal structure. The core task to develop the generalizable method was to estimate the spatiotemporal behavioral demand for each plot of land to acquire the internal structure of the life circle, as the range can be delineated primarily based on environmental data. Therefore, behavioral demand estimation models were established through logistic regression and machine learning techniques, including decision trees and ensemble learning. The model with the lowest error rate was chosen as the final estimation model for each type of land. Finally, we used a community without GPS data as an example to demonstrate the effectiveness of the estimation models and delineation method. This article extends the existing literature by introducing spatiotemporal behavioral demand estimation models, which learn the relationships between environmental contexts, population composition and the existing delineated results based on GPS data to delineate the internal structure of the community life circle without employing behavioral data. Furthermore, the proposed method and delineation results also contributes to facilities adjustments and location selections in life circle planning, people-oriented transformation in urban planning, and activity space estimation of the population in evaluating and improving the urban policies.
文摘Under the macro background of rapid urbanization and social transformation in China,campus space renewal has become an important practice and carrier for the sustainable development of schools.The study on campus space by big data and quantitative reflection of spatial distribution of applicable people in different areas of the campus can provide a certain scientific basis for campus space updating.West campus of Yangtze University is taken as research object.Based on cognitive map method,questionnaire survey method,behavior trajectory and correlation analysis method,the types and characteristics of campus space composition,campus satisfaction,usage and its relevance are analyzed.Research results show that ①the overall imageability of campus space is higher,which has a significantly positive correlation with the satisfaction of campus environment,and has no correlation with users’ behavior activities.The use frequency of non teaching areas varies greatly in different periods of time.②The correlation between the surrounding green vegetation and the image degree of campus landmarks is the most significant,and the coefficient is 0.886.③The correlation between spatial size suitability and regional image degree is the most significant,and the coefficient is 0.937.④The correlation between public activity facilities in the region and node image degree is the most significant,and the coefficient is 0.995.According to the research results,the corresponding solutions are put forward to provide scientific and quantitative reference suggestions for the renewal and transformation of the campus.
基金Ministerio de Ciencia,Innovación y Universidades(PID2021-125483NB-I00,PGC2018-095595-B-I00)。
文摘Engineering ultrashort laser pulses is crucial for advancing fundamental research fields and applications.Controlling their spatiotemporal behavior,tailored to specific applications,can unlock new experimental capabilities.However,achieving this control is particularly challenging due to the difficulty in independently structuring their intensity and spatial phase distributions,given their polychromatic bandwidth.This article addresses this challenge by presenting a technique for generating flying structured laser pulses with tunable spatiotemporal behavior.We developed a comprehensive approach to directly design and govern these laser pulses.This method elucidates the role jointly played by the pulse's spatiotemporal couplings and its prescribed phase gradient in governing the pulse dynamics.It evidences that the often-overlooked design of the phase gradient is indeed essential for achieving programmable spatiotemporal control of the pulses.By tailoring the prescribed phase gradient,we demonstrate the creation of,to our knowledge,novel families of flying structured laser pulses that travel at the speed of light in helical spring and vortex multi-ring forms of different geometries.The achieved control over the dynamics of their intensity peaks and wavefronts is analyzed in detail.For instance,the intensity peak can be configured as a THz rotating light spot or shaped as a curve,enabling simultaneous substrate illumination at rates of tens of THz,far exceeding the MHz rates typically used in laser material processing.Additionally,the independent manipulation of the pulse wavefronts allows local tuning of the orbital angular momentum density carried by the beam.Together,these advancements unveil advantageous capabilities that have been sought after for many years,especially in ultrafast optics and light-matter interaction research.
