[Objective] With the background of dramatic changes in land use patterns,the aim was to explore the ecosystem services value of Fei County based on RS and GIS.[Method] Ecological changes in the environment can bring c...[Objective] With the background of dramatic changes in land use patterns,the aim was to explore the ecosystem services value of Fei County based on RS and GIS.[Method] Ecological changes in the environment can bring changes in economic value expressed quantitatively by ecosystem service value （ESV）.According to modified ESV equivalency factor tables and three periods of interpreted TM remote sensing images in 1990,2000 and 2009,this paper calculated the total ESV in Fei County,Shandong Province,China and analyzed the relationship between ESV and the land-use changes at last.[Result] The results showed that the total ESV of the study area decreased from 2.144×109 yuan in 1990,2.139×109 yuan in 2000,and at last to 2.098×109 yuan in 2009 as the overall study area land use pattern changed dramatically,in which the built-up land increased by 23％,while the cropland and forest were constantly on the decrease.[Conclusion] The research provides theoretical support for the construction of high efficient ecological economic zone and sustainable development of the region.展开更多
To enhance user perceived performance,Akamai' s content distribution network(CDN) utilizes the domain name system(DNS) effectively to redirect users to close-by content replicas over short time scale.The use of DN...To enhance user perceived performance,Akamai' s content distribution network(CDN) utilizes the domain name system(DNS) effectively to redirect users to close-by content replicas over short time scale.The use of DNS redirection has brought a significant advantage to Akamai' s CDN.However,the reliance on DNS also poses a fundamental threat to Akamai' s content distribution model.In particular,systematic evaluation and quantification illustrates the impact of recent emerging public DNS resolving services on Akamai' s CDN,including the degradation of corresponding user perceived performance and the benefit damnification of collaborating internet services providers(ISPs) that host Akamai's edge servers.The measurement demonstrates that a considerable penetration of public DNS resolving services(e.g.,OpenDNS and GoogleDNS) effectively corrupts the Akamai' s serving model,namely the large-scale server distribution and quick DNS redirection.展开更多
基金supported by Fei county land and resources bureau of Shandong province
文摘[Objective] With the background of dramatic changes in land use patterns,the aim was to explore the ecosystem services value of Fei County based on RS and GIS.[Method] Ecological changes in the environment can bring changes in economic value expressed quantitatively by ecosystem service value （ESV）.According to modified ESV equivalency factor tables and three periods of interpreted TM remote sensing images in 1990,2000 and 2009,this paper calculated the total ESV in Fei County,Shandong Province,China and analyzed the relationship between ESV and the land-use changes at last.[Result] The results showed that the total ESV of the study area decreased from 2.144×109 yuan in 1990,2.139×109 yuan in 2000,and at last to 2.098×109 yuan in 2009 as the overall study area land use pattern changed dramatically,in which the built-up land increased by 23％,while the cropland and forest were constantly on the decrease.[Conclusion] The research provides theoretical support for the construction of high efficient ecological economic zone and sustainable development of the region.
基金Supported by the National Basic Research Program of China(No.2013CB329103)the National Natural Science Foundation of China(No.61133016,61300191)+1 种基金the National High Technology Joint Research Program of China(No.2011AA010706)the Program of SichuanProvince Applied and Basic Research(No.2013JY0116)
文摘To enhance user perceived performance,Akamai' s content distribution network(CDN) utilizes the domain name system(DNS) effectively to redirect users to close-by content replicas over short time scale.The use of DNS redirection has brought a significant advantage to Akamai' s CDN.However,the reliance on DNS also poses a fundamental threat to Akamai' s content distribution model.In particular,systematic evaluation and quantification illustrates the impact of recent emerging public DNS resolving services on Akamai' s CDN,including the degradation of corresponding user perceived performance and the benefit damnification of collaborating internet services providers(ISPs) that host Akamai's edge servers.The measurement demonstrates that a considerable penetration of public DNS resolving services(e.g.,OpenDNS and GoogleDNS) effectively corrupts the Akamai' s serving model,namely the large-scale server distribution and quick DNS redirection.
