Beijing Central Axis is the backbone of the ancient capital,a cultural spine shaped by the passage of time and spatial changes.Its successful inscription as a World Heritage site presents new opportunities for the con...Beijing Central Axis is the backbone of the ancient capital,a cultural spine shaped by the passage of time and spatial changes.Its successful inscription as a World Heritage site presents new opportunities for the conservation of the Central Axis cultural heritage,while also offering a fresh chance to link cultural and tourism sites along the Axis,fostering coordinated development.展开更多
This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns m...This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns mesh routers to identified gateways. The new algorithm can guarantee to find a feasible gateway placement satisfying Quality-of-Service (QoS) constraints, including delay constraint, relay load constraint and gateway capacity constraint. Experimental results show that its performance is as good as that of the best of existing algorithms for the gateway placement problem. But, the new algorithm can be used for BWMNs that do not form one connected component, and it is easy to implement and use.展开更多
This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Ma...This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Many areas warrantfurther investigation and much optimization remains to be done. The fascinatingchemistry of phosphorus poses interesting hurdles but at the same time leavesample room for polymer scientists to exercise their creativity in designinginteresting biomaterials. As the mutual understanding between basic and clinicalscientists on the need of medical devices and the capabilities of these newbiomaterials expands, imaginative application of new biomaterials to other medi-cal applications can be expected.展开更多
The virtual backbone is an approach for solving routing problems in wireless ad hoc and sensor networks. A connected dominating set (CDS) was proposed as a virtual backbone to improve the performance of wireless netwo...The virtual backbone is an approach for solving routing problems in wireless ad hoc and sensor networks. A connected dominating set (CDS) was proposed as a virtual backbone to improve the performance of wireless networks. The quality of a virtual backbone is measured not only by approximation factor, which is the ratio of its size to that of minimum CDS, but also time complexity and message complexity. In this paper, a distributed algorithm is presented to construct a minimum CDS for ad hoc and sensor networks. By destroying triangular loops in the virtual backbone, the proposed algorithm can effectively construct a CDS with smaller size. Moreover, our algorithm, which is fully localized, has a constant approximation ratio, linear message and time complexity, and low implementation complexity. The simulation results and theoretical analysis show that our algorithm has better efficiency and performance than conventional approaches.展开更多
Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding ...Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding the configuration evolution.In this paper,we uncover the configuration evolution of an operational IP backbone based on the weekly reports gathered from January 2006 to January 2013.We find that rate limiting and launching routes for new customers are configured most frequently.In addition,we conduct an analysis of network failures and find that link failures are the main causes for network failures.We suggest that we should configure redundant links for the links which are easy to break down.At last,according to the analysis results,we illustrate how to provide semi-automated configuration for rate limiting and adding customers.展开更多
文摘Beijing Central Axis is the backbone of the ancient capital,a cultural spine shaped by the passage of time and spatial changes.Its successful inscription as a World Heritage site presents new opportunities for the conservation of the Central Axis cultural heritage,while also offering a fresh chance to link cultural and tourism sites along the Axis,fostering coordinated development.
文摘This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns mesh routers to identified gateways. The new algorithm can guarantee to find a feasible gateway placement satisfying Quality-of-Service (QoS) constraints, including delay constraint, relay load constraint and gateway capacity constraint. Experimental results show that its performance is as good as that of the best of existing algorithms for the gateway placement problem. But, the new algorithm can be used for BWMNs that do not form one connected component, and it is easy to implement and use.
文摘This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Many areas warrantfurther investigation and much optimization remains to be done. The fascinatingchemistry of phosphorus poses interesting hurdles but at the same time leavesample room for polymer scientists to exercise their creativity in designinginteresting biomaterials. As the mutual understanding between basic and clinicalscientists on the need of medical devices and the capabilities of these newbiomaterials expands, imaginative application of new biomaterials to other medi-cal applications can be expected.
基金The National Natural Science Foundation ofChina(No.60272082)The Important Science and Technology Key Item of Shanghai(No.05dzl5004)
文摘The virtual backbone is an approach for solving routing problems in wireless ad hoc and sensor networks. A connected dominating set (CDS) was proposed as a virtual backbone to improve the performance of wireless networks. The quality of a virtual backbone is measured not only by approximation factor, which is the ratio of its size to that of minimum CDS, but also time complexity and message complexity. In this paper, a distributed algorithm is presented to construct a minimum CDS for ad hoc and sensor networks. By destroying triangular loops in the virtual backbone, the proposed algorithm can effectively construct a CDS with smaller size. Moreover, our algorithm, which is fully localized, has a constant approximation ratio, linear message and time complexity, and low implementation complexity. The simulation results and theoretical analysis show that our algorithm has better efficiency and performance than conventional approaches.
基金supported by the National Natural Science Foundation of China under Grant Nos.61602105 and 61572123China Postdoctoral Science Foundation under Grant Nos.2016M601323+1 种基金the Fundamental Research Funds for the Central Universities Project under Grant No.N150403007CERNET Innovation Project under Grant No.NGII20160126
文摘Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding the configuration evolution.In this paper,we uncover the configuration evolution of an operational IP backbone based on the weekly reports gathered from January 2006 to January 2013.We find that rate limiting and launching routes for new customers are configured most frequently.In addition,we conduct an analysis of network failures and find that link failures are the main causes for network failures.We suggest that we should configure redundant links for the links which are easy to break down.At last,according to the analysis results,we illustrate how to provide semi-automated configuration for rate limiting and adding customers.
