Based on the GIS spatial analysis technology,this paper assessed the effects of Nanchang metro in improving the accessibility of public transport networks in different spatial patterns.Besides,from the perspective of ...Based on the GIS spatial analysis technology,this paper assessed the effects of Nanchang metro in improving the accessibility of public transport networks in different spatial patterns.Besides,from the perspective of transport fairness,this paper evaluated the fairness of allocation of transportation resources for indemnificatory housing residents.Then,it revealed the reasons for the welfare loss of indemnificatory housing residents in fast rail transit resources,so as to provide a reference for promoting the space adaptation of indemnificatory housing residents.The study found that(i)the subway has improved the accessibility of the urban public transport network in terms of travel time and accessibility,but it has a different effect on improving the accessibility of the public transport network.After crossing a certain transit time and distance,there is a weakening trend,showing a pattern of"central expansion-peripheral weakness".(ii)The relative improvement of the metro on the accessibility of public transport for indemnificatory housing residents is lower than the overall improvement efficiency,and the fairness of the redistribution of transportation resources of the indemnificatory housing residents is impaired.(iii)In order to prevent and reduce the problem of space mismatch between indemnificatory housing and rail transit,it can be achieved by planning the metro network according to the spatial characteristics of indemnificatory housing residents’activities,guiding the selection of sites for indemnificatory housing with the TOD model,and forming a mixed community by combining the indemnificatory housing construction with commercial housing,to guarantee fair resource allocation of indemnificatory housing residents.展开更多
The spectral efficiency(SE)and energy efficiency(EE)tradeoff while ensuring rate fairness among users in non-orthogonal multiple access(NOMA)systems is investigated.In order to characterize the SE-EE tradeoff with rat...The spectral efficiency(SE)and energy efficiency(EE)tradeoff while ensuring rate fairness among users in non-orthogonal multiple access(NOMA)systems is investigated.In order to characterize the SE-EE tradeoff with rate fairness,a multi-objective optimization(MOO)problem is first formulated,where the rate fairness is represented with theα-fair utility function.Then,the MOO problem is converted into a single-objective optimization(SOO)problem by the weighted sum method.To solve the converted non-convex SOO problem,we apply sequential convex programming,which helps to propose a general power allocation algorithm to realize the SE-EE tradeoff with rate fairness.We prove the convergence of the proposed algorithm and the convergent solution satisfies the KKT conditions.Simulation results demonstrate the proposed power allocation algorithm can achieve various levels of rate fairness,and higher fairness results in degraded performance of SE-EE tradeoff.A pivotal conclusion is reached that NOMA systems significantly outperform orthogonal multiple access systems in terms of SE-EE tradeoff with the same level of rate fairness.展开更多
This study examines the socio-spatial context of uneven development and the residential accessibility of green space in Dalian of Liaoning Province, China. The social fairness was analyzed with a community scale as th...This study examines the socio-spatial context of uneven development and the residential accessibility of green space in Dalian of Liaoning Province, China. The social fairness was analyzed with a community scale as the basis. We combined social scientific methods with a GIS method using a behavior accessibility model from the perspectives of fairness of urban green space allocation based on social geography, geographic information science, management science and many other related discipline theories. The results show that: 1) Most of the urban green space distribution presents an unbalanced phenomenon, and it does not match with the population distribution; 2) We found some differences in the accessibility of the population with different attributes and opportunities to use and enjoy the urban green spaces, mainly due to: the dual social and spatial attributes of the residents and the serious stratum differentiation generated were the internal causes; the residential space differentiation and the pursuit of economic and real estate development were the direct causes; and unreasonable planning, in regard to the fact that government policies did not give consideration to efficiency and fairness, was also an important factor.展开更多
1 Introduction The primary goal of the Deep-time Digital Earth project is to develop an open collaboration and data sharing platform that enables the transition of deep-time geoscientific research to a Big Data driven...1 Introduction The primary goal of the Deep-time Digital Earth project is to develop an open collaboration and data sharing platform that enables the transition of deep-time geoscientific research to a Big Data driven paradigm.Such an open platform will require the ability to effectively and efficiently access and integrate a wide variety of digital Earth data.展开更多
The main objective of multiuser orthogonal frequency division multiple access(MU-OFDM) is to maximize the total system capacity in wireless communication systems. Thus, the problem in MU-OFDM system is the adaptive al...The main objective of multiuser orthogonal frequency division multiple access(MU-OFDM) is to maximize the total system capacity in wireless communication systems. Thus, the problem in MU-OFDM system is the adaptive allocation of the resources(subcarriers, bits and power) to different users subject to several restrictions to maximize the total system capacity. In this work, a proposed subcarrier allocation algorithm was presented to assign the subcarriers with highest channel gain to the users. After the subcarrier allocation, subcarrier gain-based power allocation(SGPA) was employed for power and bit loading. The simulation results show that the proposed subcarrier-power allocation scheme can achieve high total system capacity and good fairness in allocating the resources to the users with slightly high computational complexity compared to the existing subcarrier allocation algorithms.展开更多
A resource allocation problem considering both efficiency and fairness in orthogonal frequency division multiple access （OFDMA） systems is studied. According to the optimality conditions, a downlink resource allocat...A resource allocation problem considering both efficiency and fairness in orthogonal frequency division multiple access （OFDMA） systems is studied. According to the optimality conditions, a downlink resource allocation algorithm consisting of subcarrier assignment and power alloca- tion is proposed. By adjusting the tradeoff coefficient, the proposed algorithm can achieve different levels of compromise between efficiency and fairness. The well-known classic resource allocation policies such as sum-rate maximization algorithm, proportional fairness algorithm and max-rain algorithm are all special cases of the proposed algorithm. Simulation results show that the compromise between efficiency and fairness can be continuously adjusted according to system requirements.展开更多
On the basis of inner-system labeling signaling used in the integrated access system,a kind of inner-system labeling algorithm is introduced in this paper, and the fairness of the algorithm for each traffic stream in ...On the basis of inner-system labeling signaling used in the integrated access system,a kind of inner-system labeling algorithm is introduced in this paper, and the fairness of the algorithm for each traffic stream in the integrated-services is analyzed. The base of this algorithm is Class of Services (CoS), and each packet entering the relative independent area (an autonomous system) would be labeled according to the service type or Quality of Service (QoS) in demand,and be scheduled and managed within the system (the system can be enlarged if conforming to the same protocol). The experimental results show that each of the stream rate in the integratedservices would converge to a stable value if the rates of transmitting converge to that of the receiving exponentially, that is, the effective traffic of each stream would be fair.展开更多
文摘Based on the GIS spatial analysis technology,this paper assessed the effects of Nanchang metro in improving the accessibility of public transport networks in different spatial patterns.Besides,from the perspective of transport fairness,this paper evaluated the fairness of allocation of transportation resources for indemnificatory housing residents.Then,it revealed the reasons for the welfare loss of indemnificatory housing residents in fast rail transit resources,so as to provide a reference for promoting the space adaptation of indemnificatory housing residents.The study found that(i)the subway has improved the accessibility of the urban public transport network in terms of travel time and accessibility,but it has a different effect on improving the accessibility of the public transport network.After crossing a certain transit time and distance,there is a weakening trend,showing a pattern of"central expansion-peripheral weakness".(ii)The relative improvement of the metro on the accessibility of public transport for indemnificatory housing residents is lower than the overall improvement efficiency,and the fairness of the redistribution of transportation resources of the indemnificatory housing residents is impaired.(iii)In order to prevent and reduce the problem of space mismatch between indemnificatory housing and rail transit,it can be achieved by planning the metro network according to the spatial characteristics of indemnificatory housing residents’activities,guiding the selection of sites for indemnificatory housing with the TOD model,and forming a mixed community by combining the indemnificatory housing construction with commercial housing,to guarantee fair resource allocation of indemnificatory housing residents.
基金Supported by the Fundamental Research Funds for the Central Universities(2016RC055)
文摘The spectral efficiency(SE)and energy efficiency(EE)tradeoff while ensuring rate fairness among users in non-orthogonal multiple access(NOMA)systems is investigated.In order to characterize the SE-EE tradeoff with rate fairness,a multi-objective optimization(MOO)problem is first formulated,where the rate fairness is represented with theα-fair utility function.Then,the MOO problem is converted into a single-objective optimization(SOO)problem by the weighted sum method.To solve the converted non-convex SOO problem,we apply sequential convex programming,which helps to propose a general power allocation algorithm to realize the SE-EE tradeoff with rate fairness.We prove the convergence of the proposed algorithm and the convergent solution satisfies the KKT conditions.Simulation results demonstrate the proposed power allocation algorithm can achieve various levels of rate fairness,and higher fairness results in degraded performance of SE-EE tradeoff.A pivotal conclusion is reached that NOMA systems significantly outperform orthogonal multiple access systems in terms of SE-EE tradeoff with the same level of rate fairness.
基金Under the auspices of National Natural Science Foundation of China(No.41471140)
文摘This study examines the socio-spatial context of uneven development and the residential accessibility of green space in Dalian of Liaoning Province, China. The social fairness was analyzed with a community scale as the basis. We combined social scientific methods with a GIS method using a behavior accessibility model from the perspectives of fairness of urban green space allocation based on social geography, geographic information science, management science and many other related discipline theories. The results show that: 1) Most of the urban green space distribution presents an unbalanced phenomenon, and it does not match with the population distribution; 2) We found some differences in the accessibility of the population with different attributes and opportunities to use and enjoy the urban green spaces, mainly due to: the dual social and spatial attributes of the residents and the serious stratum differentiation generated were the internal causes; the residential space differentiation and the pursuit of economic and real estate development were the direct causes; and unreasonable planning, in regard to the fact that government policies did not give consideration to efficiency and fairness, was also an important factor.
基金the US National Science Foundation for their long-time support of the development of the IGSN(Grant Nos.NSF-0445178,NSF-0514551,NSF-0552123)the Earth Chem system(Grant No.NSF-0522195)+1 种基金operation of both systems as part of the IEDA Data Facility(Grant Nos.NSF-0950477,NSF-1636653)the Alfred P.Sloan Foundation for a grant to Columbia University to support the development of a global,scalable,and sustainable technical and organizational infrastructure for persistent unique identifiers of physical scientific samples.
文摘1 Introduction The primary goal of the Deep-time Digital Earth project is to develop an open collaboration and data sharing platform that enables the transition of deep-time geoscientific research to a Big Data driven paradigm.Such an open platform will require the ability to effectively and efficiently access and integrate a wide variety of digital Earth data.
文摘The main objective of multiuser orthogonal frequency division multiple access(MU-OFDM) is to maximize the total system capacity in wireless communication systems. Thus, the problem in MU-OFDM system is the adaptive allocation of the resources(subcarriers, bits and power) to different users subject to several restrictions to maximize the total system capacity. In this work, a proposed subcarrier allocation algorithm was presented to assign the subcarriers with highest channel gain to the users. After the subcarrier allocation, subcarrier gain-based power allocation(SGPA) was employed for power and bit loading. The simulation results show that the proposed subcarrier-power allocation scheme can achieve high total system capacity and good fairness in allocating the resources to the users with slightly high computational complexity compared to the existing subcarrier allocation algorithms.
文摘A resource allocation problem considering both efficiency and fairness in orthogonal frequency division multiple access （OFDMA） systems is studied. According to the optimality conditions, a downlink resource allocation algorithm consisting of subcarrier assignment and power alloca- tion is proposed. By adjusting the tradeoff coefficient, the proposed algorithm can achieve different levels of compromise between efficiency and fairness. The well-known classic resource allocation policies such as sum-rate maximization algorithm, proportional fairness algorithm and max-rain algorithm are all special cases of the proposed algorithm. Simulation results show that the compromise between efficiency and fairness can be continuously adjusted according to system requirements.
基金） Supported by the National Natural Science Foundation of China （No. 61001115）, the National Major Science and Technology Project （No. 2011ZX03001- 007-03）, and the Natural Science Foundation of Beijing （No. 4102044）.
文摘On the basis of inner-system labeling signaling used in the integrated access system,a kind of inner-system labeling algorithm is introduced in this paper, and the fairness of the algorithm for each traffic stream in the integrated-services is analyzed. The base of this algorithm is Class of Services (CoS), and each packet entering the relative independent area (an autonomous system) would be labeled according to the service type or Quality of Service (QoS) in demand,and be scheduled and managed within the system (the system can be enlarged if conforming to the same protocol). The experimental results show that each of the stream rate in the integratedservices would converge to a stable value if the rates of transmitting converge to that of the receiving exponentially, that is, the effective traffic of each stream would be fair.
