Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combin...Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combination of single copy scheme and multi-copy scheme and the combination of hop-by-hop and multi-hop mechanism ACHR,which has the advantages in simplicity,availability and well-expansibility.The result shows that it can take advantage of the random communication opportunities and local network connectivity,and achieves 1.6 times delivery ratio and 60% overhead compared with its counterpart.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
This paper reviews the importance of visibility in public deliberation in the theoretical construction of political communication. Political communication is the area that study social and political interactions of ac...This paper reviews the importance of visibility in public deliberation in the theoretical construction of political communication. Political communication is the area that study social and political interactions of actors through discourses and practices within the public sphere. The social and political actors manage their public appearances in an exercise of visibility, allowing deliberation of public affairs. In recent years, Mexico has been a relevant case of study for understanding the opening of media into the public discussion of governmental affairs. As an example, this paper presents an analysis of public deliberation in the city of Quer6taro, Mexico. This study analyses political participation and openness of media, based on the concepts visibility, public sphere and citizenship. The analysis was built on the idea that the press concentrates most of the issues of public interest and that it reflects actors and arguments given for deliberation. In a qualitative approximation, we analyzed the discourses published in four journals and developed an analytical framework that illustrates the levels of access and visibility of a variety of political and social actors. This exercise demonstrates the importance of the concept of visibility in public deliberation and the media as managers in the current configuration of political communication.展开更多
基金Project(531107040202) supported by the Fundamental Research Funds for the Central Universities of China
文摘Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combination of single copy scheme and multi-copy scheme and the combination of hop-by-hop and multi-hop mechanism ACHR,which has the advantages in simplicity,availability and well-expansibility.The result shows that it can take advantage of the random communication opportunities and local network connectivity,and achieves 1.6 times delivery ratio and 60% overhead compared with its counterpart.
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.
文摘This paper reviews the importance of visibility in public deliberation in the theoretical construction of political communication. Political communication is the area that study social and political interactions of actors through discourses and practices within the public sphere. The social and political actors manage their public appearances in an exercise of visibility, allowing deliberation of public affairs. In recent years, Mexico has been a relevant case of study for understanding the opening of media into the public discussion of governmental affairs. As an example, this paper presents an analysis of public deliberation in the city of Quer6taro, Mexico. This study analyses political participation and openness of media, based on the concepts visibility, public sphere and citizenship. The analysis was built on the idea that the press concentrates most of the issues of public interest and that it reflects actors and arguments given for deliberation. In a qualitative approximation, we analyzed the discourses published in four journals and developed an analytical framework that illustrates the levels of access and visibility of a variety of political and social actors. This exercise demonstrates the importance of the concept of visibility in public deliberation and the media as managers in the current configuration of political communication.
