Recently, the IP connectivity during the Mobile Node (MN) movement between Base Stations (BSs) belonging to different Internet Service Providers (ISPs) is still a key issue to be tackled. In this paper, therefore, we ...Recently, the IP connectivity during the Mobile Node (MN) movement between Base Stations (BSs) belonging to different Internet Service Providers (ISPs) is still a key issue to be tackled. In this paper, therefore, we develop a new scheme to improve the performance of inter-domain fast handover over mobile WiMAX networks. The framework basically relies on the Fast Handover for Mobile IPv6 protocol (FMIPv6) when the Media Independent Information Services (MIIS) as defined in IEEE802.21 standard is applied to enable the Mobile Node in storing the information of the neighboring networks. A Fully Qualified Domain Name (FQDN) is also used to identify the IP address of the previous network operator and the MN during its movements. Since both MIIS and FQDN can support the node mobility between multiple domains, our proposed scheme can also be called P-FMIPv6. The numerical results show that the latency of IP connectivity of this proposed handover can be significantly reduced in addition to less service disruption time during handovers as compared to the existing FMIPv6 when IEEE802.16e network is considered.展开更多
Dralll is a type liP restriction endonucleases （REases） that recognizes and creates a double strand break within the gapped palindromic sequence CACTNNN^GTG of double-stranded DNA indicates nicking on the bottom st...Dralll is a type liP restriction endonucleases （REases） that recognizes and creates a double strand break within the gapped palindromic sequence CACTNNN^GTG of double-stranded DNA indicates nicking on the bottom strand; indicates nicking on the top strand）. However, wild type Dralll shows significant star activity. In this study, it was found that the prominent star site is CATSGTT;GTG, consisting of a star 5＇ half （CAT） and a canonical 3＇ half （GTG）. Dralll nicks the 3＇ canonical half site at a faster rate than the 5＇ star half site, in contrast to the similar rate with the canonical full site. The crystal structure of the Dralll protein was solved. It indicated, as supported by mutagenesis, that Dralll possesses a ~13a- metal HNH active site. The structure revealed extensive intra-molecular interactions between the N-terminal domain and the C-terminal domain containing the HNH active site. Disruptions of these interactions through site- directed mutagenesis drastically increased cleavage fidelity. The understanding of fidelity mechanisms will enable generation of high fidelity REases.展开更多
互联网是促进现代社会经济发展和科技创新的重要信息基础设施;然而,支撑并规范互联网正常运行的关键核心技术——互联网的TCP/IP(Transport Control Protocol/Internet Protocol)体系结构——几十年来几乎保持不变.本文首先从技术自身...互联网是促进现代社会经济发展和科技创新的重要信息基础设施;然而,支撑并规范互联网正常运行的关键核心技术——互联网的TCP/IP(Transport Control Protocol/Internet Protocol)体系结构——几十年来几乎保持不变.本文首先从技术自身弊端、社会发展需求、技术转移周期、科技革命规律四个方面论述了开展互联网体系结构创新的必要性.其次,运用系统科学原理阐明了TCP/IP体系结构弊端的根源.再次,运用系统观念揭示了信息网络的功能本质和网络间的互联本质,发现了信息传递的四个自然属性(对象属性、身份属性、位置属性、手段属性).在此基础上,简要介绍了基于两个本质和四个自然属性开展创新互联网体系结构创新的实例——共生网络.最后,结合共生网络架构展望了部署新型互联网体系结构的总体路径.展开更多
Cooperation among service providers, network providers, and access providers in the Internet allows the creation of new services to offer to customers that are in other domains, thus increasing revenue. However, the I...Cooperation among service providers, network providers, and access providers in the Internet allows the creation of new services to offer to customers that are in other domains, thus increasing revenue. However, the Internet heterogeneous environment, where each provider has its own policies, infrastructure and business goals, hinders the deployment of more advanced communication services. This paper presents a Quality of Service （QoS） for Inter-Domain Services （QIDS） model that allows inter-domain QoS-aware services to be defined, configured, and adapted in a dynamic and on-demand fashion, among service providers. This is accomplished by： 1） the use of a common communication channel （business layer） where service providers publish and search for services, and interact with each other to contract and manage these services; 2） the templates to specify the business and technical characteristics of the services; 3） the automatic composition of services using service dements （smaller services） a^cording to performance and service-specific QoS parameters; and 4） the creation and enforcement of configuration rules for the underlying infrastructure. A prototype was implemented to validate QIDS and performance tests were conducted on an inter-domain Border Gateway Protocol （BGP）/Multiprotocol Label Switching （MPLS） Virtual Private Network （VPN） scenario.展开更多
文摘Recently, the IP connectivity during the Mobile Node (MN) movement between Base Stations (BSs) belonging to different Internet Service Providers (ISPs) is still a key issue to be tackled. In this paper, therefore, we develop a new scheme to improve the performance of inter-domain fast handover over mobile WiMAX networks. The framework basically relies on the Fast Handover for Mobile IPv6 protocol (FMIPv6) when the Media Independent Information Services (MIIS) as defined in IEEE802.21 standard is applied to enable the Mobile Node in storing the information of the neighboring networks. A Fully Qualified Domain Name (FQDN) is also used to identify the IP address of the previous network operator and the MN during its movements. Since both MIIS and FQDN can support the node mobility between multiple domains, our proposed scheme can also be called P-FMIPv6. The numerical results show that the latency of IP connectivity of this proposed handover can be significantly reduced in addition to less service disruption time during handovers as compared to the existing FMIPv6 when IEEE802.16e network is considered.
基金Supported by the National Natural Science Foundation of China （No. 60372096）, the Program for Century Excellent Talents in University （No. NCET- 05-0112） and the High Technology Research and Development Program of China （No. 2006AA01Z246）.
文摘Dralll is a type liP restriction endonucleases （REases） that recognizes and creates a double strand break within the gapped palindromic sequence CACTNNN^GTG of double-stranded DNA indicates nicking on the bottom strand; indicates nicking on the top strand）. However, wild type Dralll shows significant star activity. In this study, it was found that the prominent star site is CATSGTT;GTG, consisting of a star 5＇ half （CAT） and a canonical 3＇ half （GTG）. Dralll nicks the 3＇ canonical half site at a faster rate than the 5＇ star half site, in contrast to the similar rate with the canonical full site. The crystal structure of the Dralll protein was solved. It indicated, as supported by mutagenesis, that Dralll possesses a ~13a- metal HNH active site. The structure revealed extensive intra-molecular interactions between the N-terminal domain and the C-terminal domain containing the HNH active site. Disruptions of these interactions through site- directed mutagenesis drastically increased cleavage fidelity. The understanding of fidelity mechanisms will enable generation of high fidelity REases.
文摘互联网是促进现代社会经济发展和科技创新的重要信息基础设施;然而,支撑并规范互联网正常运行的关键核心技术——互联网的TCP/IP(Transport Control Protocol/Internet Protocol)体系结构——几十年来几乎保持不变.本文首先从技术自身弊端、社会发展需求、技术转移周期、科技革命规律四个方面论述了开展互联网体系结构创新的必要性.其次,运用系统科学原理阐明了TCP/IP体系结构弊端的根源.再次,运用系统观念揭示了信息网络的功能本质和网络间的互联本质,发现了信息传递的四个自然属性(对象属性、身份属性、位置属性、手段属性).在此基础上,简要介绍了基于两个本质和四个自然属性开展创新互联网体系结构创新的实例——共生网络.最后,结合共生网络架构展望了部署新型互联网体系结构的总体路径.
文摘Cooperation among service providers, network providers, and access providers in the Internet allows the creation of new services to offer to customers that are in other domains, thus increasing revenue. However, the Internet heterogeneous environment, where each provider has its own policies, infrastructure and business goals, hinders the deployment of more advanced communication services. This paper presents a Quality of Service （QoS） for Inter-Domain Services （QIDS） model that allows inter-domain QoS-aware services to be defined, configured, and adapted in a dynamic and on-demand fashion, among service providers. This is accomplished by： 1） the use of a common communication channel （business layer） where service providers publish and search for services, and interact with each other to contract and manage these services; 2） the templates to specify the business and technical characteristics of the services; 3） the automatic composition of services using service dements （smaller services） a^cording to performance and service-specific QoS parameters; and 4） the creation and enforcement of configuration rules for the underlying infrastructure. A prototype was implemented to validate QIDS and performance tests were conducted on an inter-domain Border Gateway Protocol （BGP）/Multiprotocol Label Switching （MPLS） Virtual Private Network （VPN） scenario.
