Traffic accessibility and the coupling degree of ecosystem services supply and demand in the middle reaches of the Yangtze River urban agglomeration,China

The spatial relationships between traffic accessibility and supply and demand(S&D)of ecosystem services(ESs)are essential for the formulation of ecological compensation policies and ESs regulation.In this study,an ESs matrix and coupling analysis method were used to assess ESs S&D based on land-use data for 2000,2010,and 2020,and spatial regression models were used to analyze the correlated impacts of traffic accessibility.The results showed that the ESs supply and balance index in the middle reaches of the Yangtze River urban agglomeration(MRYRUA)continuously decreased,while the demand index increased from 2000 to 2020.The Gini coefficients of these indices continued to increase but did not exceed the warning value(0.4).The coupling degree of ESs S&D continued to increase,and its spatial distribution patterns were similar to that of the ESs demand index,with significantly higher values in the plains than in the montane areas,contrasting with those of the ESs supply index.The results of global bivariate Moran’s I analysis showed a significant spatial dependence between traffic accessibility and the degree of coupling between ESs S&D;the spatial regression results showed that an increase in traffic accessibility promoted the coupling degree.The present results provide a new perspective on the relationship between traffic accessibility and the coupling degree of ESs S&D,representing a case study for similar future research in other regions,and a reference for policy creation based on the matching between ESs S&D in the MRYRUA.

Impacts of traffic accessibility on ecosystem services:An integrated spatial approach

The continuous degradation of ecosystem services is an important challenge faced by the world.Improvements in transportation infrastructure have had substantial impacts on economic development and ecosystem services.Exploring the influence of traffic accessibility on ecosystem services can delay or stop their deterioration;however,studies on its impact are lacking.This study addresses this gap by analysing the impact of traffic accessibility on ecosystem services using an integrated spatial regression approach based on an evaluation of the ecosystem services value(ESV)and traffic accessibility in the Middle Reaches of the Yangtze River Urban Agglomeration(MRYRUA)in China.The results indicated that the ESV in the MRYRUA continuously decreased during the study period,and the average ESV in plain areas,areas surrounding the core cities,and areas along the main traffic routes was significantly lower than that in areas along the Yangtze River and the surrounding mountainous areas.Traffic accessibility continued to increase during the study period,and the high-value areas centred on Wuhan,Changsha,Nanchang,and Yichang were radially distributed.The global bivariate spatial autocorrelation coefficient between the average ESV and traffic accessibility was negative.The average ESV and traffic accessibility exhibited significant spatial dependence and spatial heterogeneity.Spatial regression also proved that there was a negative association between the average ESV and traffic accessibility,and scale effects were evident.The findings of this study have important policy implications for future ecological protection and transportation planning.

How fast is it to city centers?The average travel speed as an indicator of road traffic accessibility potential

Transportation is the lifeblood of a modern metropolis.Accessibility generally refers to the interconnection between nodes in a regional traffic network.The purpose of the paper is to obtain more realistic and accurate measures of travel speed and to study the road traffic accessibility potential in cities.This study proposes a method for analyzing road traffic accessibility potential which is based on the average travel speed to city centers in off-peak times and which ranks 80 cities around the world.Based on the Suomi National Polar-Orbiting Partnership satellite’s visible-infrared imaging radiometer suite(NPP-VIIRS)night-time light data,urban built-up areas and city centers were extracted.Further,with the aid of the Google Maps application programming interface(API)network crawling technique,travel times and travel distances for several optimal routes to city centers by car were obtained.Feasible proposals for improving road traffic accessibility and planning urban transportation in different cities are presented.The proposed method offers a new possibility of analyzing traffic accessibility using internet data and geo-spatial methods.

On Minimizing Delay with Probabilistic Splitting of Traffic Flow in Heterogeneous Wireless Networks

In the paper,we propose a framework to investigate how to effectively perform traffic flow splitting in heterogeneous wireless networks from a queue point.The average packet delay in heterogeneous wireless networks is derived in a probabilistic manner.The basic idea can be understood via treating the integrated heterogeneous wireless networks as different coupled and parallel queuing systems.The integrated network performance can approach that of one queue with maximal the multiplexing gain.For the purpose of illustrating the effectively of our proposed model,the Cellular/WLAN interworking is exploited.To minimize the average delay,a heuristic search algorithm is used to get the optimal probability of splitting traffic flow.Further,a Markov process is applied to evaluate the performance of the proposed scheme and compare with that of selecting the best network to access in terms of packet mean delay and blocking probability.Numerical results illustrate our proposed framework is effective and the flow splitting transmission can obtain more performance gain in heterogeneous wireless networks.