根据用户需要,快速的产生、利用和管理新的服务是推动可编程网络研究的一个关键因素。这个研究领域所取得的结果,对客户、服务提供商、设备提供者甚至对整个电信部门,如宽带、移动、IP网络都有很大的影响。现在的ISPs(Internet Service ...根据用户需要,快速的产生、利用和管理新的服务是推动可编程网络研究的一个关键因素。这个研究领域所取得的结果,对客户、服务提供商、设备提供者甚至对整个电信部门,如宽带、移动、IP网络都有很大的影响。现在的ISPs(Internet Service Providers)和将来的ISPs之间竞争的关键是对市场需求的反应速度。引进新的服务种类是一项富有挑战性的工作,这需要在产生服务的方法和工具上有很大的提高和进步;需要大量具体的服务的计算、数据处理和交换;并且必须提供新的网络编程环境来使将来的网络基础是开放的、可扩展的、可编程的。在网络发展的推动下,可编程网络(Programmable Network)应运而生。展开更多
With the rapid growth of mobile data traffic and vast traffic offloaded from cellular network, Wi-Fi has been considered as an essential component to cope with the tremendous growth of mobile data traffic. Although op...With the rapid growth of mobile data traffic and vast traffic offloaded from cellular network, Wi-Fi has been considered as an essential component to cope with the tremendous growth of mobile data traffic. Although operators have deployed a lot of carrier grade Wi-Fi networks, but there are still a multitude of arrears for nowadays Wi-Fi networks, such as supporting seamless handover between APs, automatic network access and unified authentication, etc. In this paper, we propose an SDN based carrier grade Wi-Fi network framework, namely SWN. The key conceptual contribution of SWN is a principled refactoring of Wi-Fi networks into control and data planes. The control plane has a centralized global view of the whole network, can perceive the underlying network state by network situation awareness(NAS) technique, and bundles the perceived information and network management operations into northbound Application Programming Interface(API) for upper applications. In the data plane, we construct software access point(SAP) to abstract the connection between user equipment(UE) and access point(AP). Network operators can design network applications by utilizing these APIs and the SAP abstraction to configure and manage the whole network, which makes carrier grade Wi-Fi networks more flexible, user-friendly, and scalable.展开更多
Three-layer feedforward networks have been widely used in modeling chemical engineering processes and prior-knowledge-based methods have been introduced to improve their performances.In this paper,we propose the metho...Three-layer feedforward networks have been widely used in modeling chemical engineering processes and prior-knowledge-based methods have been introduced to improve their performances.In this paper,we propose the methodology of designing better prior-knowledge-based hybrid methods by combining the existing ones. Then according to this methodology,two hybrid methods,interpolation-optimization (IO) method and interpolation penalty-function (IPF) method,are designed as examples.Finally,both methods are applied to modeling two cases in chemical engineering to investigate their effectiveness.Simulation results show that the performances of the hybrid methods are better than those of their parents.展开更多
文摘根据用户需要,快速的产生、利用和管理新的服务是推动可编程网络研究的一个关键因素。这个研究领域所取得的结果,对客户、服务提供商、设备提供者甚至对整个电信部门,如宽带、移动、IP网络都有很大的影响。现在的ISPs(Internet Service Providers)和将来的ISPs之间竞争的关键是对市场需求的反应速度。引进新的服务种类是一项富有挑战性的工作,这需要在产生服务的方法和工具上有很大的提高和进步;需要大量具体的服务的计算、数据处理和交换;并且必须提供新的网络编程环境来使将来的网络基础是开放的、可扩展的、可编程的。在网络发展的推动下,可编程网络(Programmable Network)应运而生。
基金supported by the WLAN achievement transformation based on SDN project of Beijing Municipal Commission of Education,the grant number is 201501001
文摘With the rapid growth of mobile data traffic and vast traffic offloaded from cellular network, Wi-Fi has been considered as an essential component to cope with the tremendous growth of mobile data traffic. Although operators have deployed a lot of carrier grade Wi-Fi networks, but there are still a multitude of arrears for nowadays Wi-Fi networks, such as supporting seamless handover between APs, automatic network access and unified authentication, etc. In this paper, we propose an SDN based carrier grade Wi-Fi network framework, namely SWN. The key conceptual contribution of SWN is a principled refactoring of Wi-Fi networks into control and data planes. The control plane has a centralized global view of the whole network, can perceive the underlying network state by network situation awareness(NAS) technique, and bundles the perceived information and network management operations into northbound Application Programming Interface(API) for upper applications. In the data plane, we construct software access point(SAP) to abstract the connection between user equipment(UE) and access point(AP). Network operators can design network applications by utilizing these APIs and the SAP abstraction to configure and manage the whole network, which makes carrier grade Wi-Fi networks more flexible, user-friendly, and scalable.
基金Supported by the National Natural Science Foundation of China (No. 20076041)
文摘Three-layer feedforward networks have been widely used in modeling chemical engineering processes and prior-knowledge-based methods have been introduced to improve their performances.In this paper,we propose the methodology of designing better prior-knowledge-based hybrid methods by combining the existing ones. Then according to this methodology,two hybrid methods,interpolation-optimization (IO) method and interpolation penalty-function (IPF) method,are designed as examples.Finally,both methods are applied to modeling two cases in chemical engineering to investigate their effectiveness.Simulation results show that the performances of the hybrid methods are better than those of their parents.
