With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologi...With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologies for the network control and management.These two technologies could be combined together to construct a software defined self-managing solution for the future network.An autonomic QoS management mechanism in Software Defined Network(AQSDN) is proposed in this paper.In AQSDN,the various QoS features can be configured autonomically in an OpenFlow switch through extending the OpenFlow and OF-Config protocols.Based on AQSDN,a novel packet context-aware QoS model(PCaQoS) is also introduced for improving the network QoS.PCaQoS takes packet context into account when packet is marked and managed into forwarding queues.The implementation of a video application's prototype which evaluates the self-configuration feature of the AQSDN and the enhancement ability of the PCaQoS is presented in order to validate this design.展开更多
Planning and decision-making technology at intersections is a comprehensive research problem in intelligent transportation systems due to the uncertainties caused by a variety of traffic participants.As wireless commu...Planning and decision-making technology at intersections is a comprehensive research problem in intelligent transportation systems due to the uncertainties caused by a variety of traffic participants.As wireless communication advances,vehicle infrastructure integrated algorithms designed for intersection planning and decision-making have received increasing attention.In this paper,the recent studies on the planning and decision-making technologies at intersections are primarily overviewed.The general planning and decision-making approaches are presented,which include graph-based approach,prediction base approach,optimization-based approach and machine learning based approach.Since connected autonomous vehicles(CAVs)is the future direction for the automated driving area,we summarized the evolving planning and decision-making methods based on vehicle infrastructure cooperative technologies.Both four-way signalized and unsignalized intersection(s)are investigated under purely automated driving traffic and mixed traffic.The study benefit from current strategies,protocols,and simulation tools to help researchers identify the presented approaches’challenges and determine the research gaps,and several remaining possible research problems that need to be solved in the future.展开更多
Achieving high programmability has become an essential aim of network research due to the ever-increasing internet traffic.Software-Defined Network(SDN)is an emerging architecture aimed to address this need.However,ma...Achieving high programmability has become an essential aim of network research due to the ever-increasing internet traffic.Software-Defined Network(SDN)is an emerging architecture aimed to address this need.However,maintaining accurate knowledge of the network after a failure is one of the largest challenges in the SDN.Motivated by this reality,this paper focuses on the use of self-healing properties to boost the SDN robustness.This approach,unlike traditional schemes,is not based on proactively configuring multiple(and memory-intensive)backup paths in each switch or performing a reactive and time-consuming routing computation at the controller level.Instead,the control paths are quickly recovered by local switch actions and subsequently optimized by global controller knowledge.Obtained results show that the proposed approach recovers the control topology effectively in terms of time and message load over a wide range of generated networks.Consequently,scalability issues of traditional fault recovery strategies are avoided.展开更多
Improvement of English language teachers＇ roles in China seems to be of great importance for future sustainable development. First, teachers ought to shift their functions from being authoritative instructors to beco...Improvement of English language teachers＇ roles in China seems to be of great importance for future sustainable development. First, teachers ought to shift their functions from being authoritative instructors to becoming practical advisors. Good English instructions are supposed to be accompanied with reasonable advice. Second, teachers should learn to be autonomous managers with their own ways of designing academic administration. Besides, teachers and students are like co-actors of a certain drama, acting simultaneously on the stage. They ought to be good academic partners.展开更多
With the increase of system scale, the inherent reliability of supercomputers becomes lower and lower. The cost of fault handling and task recovery increases so rapidly that the reliability issue will soon harm the us...With the increase of system scale, the inherent reliability of supercomputers becomes lower and lower. The cost of fault handling and task recovery increases so rapidly that the reliability issue will soon harm the usability of supercomputers. This issue is referred to as the ＂reliability wall＂, which is regarded as a critical problem for current and future supercomputers. To address this problem, we propose an autonomous fault-tolerant system, named Iaso, in MilkyWay- 2 system. Iaso introduces the concept of autonomous management in supercomputers. By autonomous management, the computer itself, rather than manpower, takes charge of the fault management work. Iaso automatically manage the whole lifecycle of faults, including fault detection, fault diagnosis, fault isolation, and task recovery. Iaso endows the autonomous features with MilkyWay-2 system, such as self-awareness, self-diagnosis, self-healing, and self-protection. With the help of Iaso, the cost of fault handling in supercomputers reduces from several hours to a few seconds. Iaso greatly improves the usability and reliability of MilkyWay-2 system.展开更多
基金This work was supported in part by the National High Technology Research and Development Program （863 Program） of China under Grant No. 2011AA01A101, No.2013AA013303, No.2013AA013301and National Natural science foundation of China No. 61370197 ＆ 61271041.
文摘With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologies for the network control and management.These two technologies could be combined together to construct a software defined self-managing solution for the future network.An autonomic QoS management mechanism in Software Defined Network(AQSDN) is proposed in this paper.In AQSDN,the various QoS features can be configured autonomically in an OpenFlow switch through extending the OpenFlow and OF-Config protocols.Based on AQSDN,a novel packet context-aware QoS model(PCaQoS) is also introduced for improving the network QoS.PCaQoS takes packet context into account when packet is marked and managed into forwarding queues.The implementation of a video application's prototype which evaluates the self-configuration feature of the AQSDN and the enhancement ability of the PCaQoS is presented in order to validate this design.
文摘Planning and decision-making technology at intersections is a comprehensive research problem in intelligent transportation systems due to the uncertainties caused by a variety of traffic participants.As wireless communication advances,vehicle infrastructure integrated algorithms designed for intersection planning and decision-making have received increasing attention.In this paper,the recent studies on the planning and decision-making technologies at intersections are primarily overviewed.The general planning and decision-making approaches are presented,which include graph-based approach,prediction base approach,optimization-based approach and machine learning based approach.Since connected autonomous vehicles(CAVs)is the future direction for the automated driving area,we summarized the evolving planning and decision-making methods based on vehicle infrastructure cooperative technologies.Both four-way signalized and unsignalized intersection(s)are investigated under purely automated driving traffic and mixed traffic.The study benefit from current strategies,protocols,and simulation tools to help researchers identify the presented approaches’challenges and determine the research gaps,and several remaining possible research problems that need to be solved in the future.
基金This work has been supported by the Ministerio de Economía y Competitividad of the Spanish Government under project TEC2016-76795-C6-1-R and AEI/FEDER,UE.
文摘Achieving high programmability has become an essential aim of network research due to the ever-increasing internet traffic.Software-Defined Network(SDN)is an emerging architecture aimed to address this need.However,maintaining accurate knowledge of the network after a failure is one of the largest challenges in the SDN.Motivated by this reality,this paper focuses on the use of self-healing properties to boost the SDN robustness.This approach,unlike traditional schemes,is not based on proactively configuring multiple(and memory-intensive)backup paths in each switch or performing a reactive and time-consuming routing computation at the controller level.Instead,the control paths are quickly recovered by local switch actions and subsequently optimized by global controller knowledge.Obtained results show that the proposed approach recovers the control topology effectively in terms of time and message load over a wide range of generated networks.Consequently,scalability issues of traditional fault recovery strategies are avoided.
文摘Improvement of English language teachers＇ roles in China seems to be of great importance for future sustainable development. First, teachers ought to shift their functions from being authoritative instructors to becoming practical advisors. Good English instructions are supposed to be accompanied with reasonable advice. Second, teachers should learn to be autonomous managers with their own ways of designing academic administration. Besides, teachers and students are like co-actors of a certain drama, acting simultaneously on the stage. They ought to be good academic partners.
基金Acknowledgements This work was partially supported by National High-tech R＆D Program of China （863 Program） （2012AA01A301, 2012AA010901）, by Program for New Century Excellent Talents in University and by National Natural Science Foundation of China （Grant Nos. 61272142, 61103082, 61170261, and 61103193）.
文摘With the increase of system scale, the inherent reliability of supercomputers becomes lower and lower. The cost of fault handling and task recovery increases so rapidly that the reliability issue will soon harm the usability of supercomputers. This issue is referred to as the ＂reliability wall＂, which is regarded as a critical problem for current and future supercomputers. To address this problem, we propose an autonomous fault-tolerant system, named Iaso, in MilkyWay- 2 system. Iaso introduces the concept of autonomous management in supercomputers. By autonomous management, the computer itself, rather than manpower, takes charge of the fault management work. Iaso automatically manage the whole lifecycle of faults, including fault detection, fault diagnosis, fault isolation, and task recovery. Iaso endows the autonomous features with MilkyWay-2 system, such as self-awareness, self-diagnosis, self-healing, and self-protection. With the help of Iaso, the cost of fault handling in supercomputers reduces from several hours to a few seconds. Iaso greatly improves the usability and reliability of MilkyWay-2 system.
