In order to provide a theoretical guide for choosing the material for the hawsers for the FPSO side-by-side offloading system, which is moored by the yoke system, the 3D potential flow theory and full coupled time-dom...In order to provide a theoretical guide for choosing the material for the hawsers for the FPSO side-by-side offloading system, which is moored by the yoke system, the 3D potential flow theory and full coupled time-domain analysis are presented to study the dynamic response of the offloading system. The MingZhu FPSO offloading system in the field BZ25-1 is simulated here; and four different characteristic fiber ropes are used as the material for the hawsers. To acquire an accurate hawser line tension, the polynomial fitting method is used to calculate the nonlinear stiffness of the hawsers. By comparing the hawser lines＇ tension and the relative motion between the FPSO and the shuttle tanker, a suitable material for the hawser lines is chosen and discussed in this paper. The results indicate that the nonlinear stiffness characteristic of the fiber rope has a small effect on the relative motion of the vessels, but the hawser lines＇ tension is greatly influenced by the different characteristics of the fiber ropes. The hawser lines＇ tension with nonlinear stiffness is in accordance with the one with the upper and lower bound linear stiffness, which proves this method of fitting the fiber ropes＇ nonlinear stiffness is reasonable and reliable.展开更多
计算密集型任务数量的增加导致智能移动设备(Smart Mobile Devices,SMD)计算任务过载,借助MEC(Mobile Edge Computing Servers)及利用网络中空闲边缘设备(Edge Devices,ED)可使计算能力受限的SMD将计算任务卸载到MEC和ED协作中,并基于...计算密集型任务数量的增加导致智能移动设备(Smart Mobile Devices,SMD)计算任务过载,借助MEC(Mobile Edge Computing Servers)及利用网络中空闲边缘设备(Edge Devices,ED)可使计算能力受限的SMD将计算任务卸载到MEC和ED协作中,并基于委托信誉证明(Delegated Proof of Reputation,DPoR)共识机制增强系统的安全性。文中提出一种基于鸟群人工鱼群算法(Bird Swarm-Artificial Fish Swarm Algorithm,BS-AFSA)的区块链移动边缘计算卸载模型,将任务卸载问题转化为优化目标函数来降低计算开销。采用改进鸟群人工鱼群算法来优化任务时延和能量消耗,对算法中的行为参数进行针对性构造,并改进拥挤度因子来提高后期迭代中寻优的局部搜索精度。仿真结果表明,与其他基准算法相比,文中所提算法减少了陷入局部最优的可能性,并降低了联合卸载方案的系统总开销。展开更多
As the rapid growth of mobile social networks,mobile peer-to-peer(P2P)communications and mobile edge computing(MEC)have been developed to reduce the traffic load and improve the computation capacity of cellular networ...As the rapid growth of mobile social networks,mobile peer-to-peer(P2P)communications and mobile edge computing(MEC)have been developed to reduce the traffic load and improve the computation capacity of cellular networks.However,the stability of social network is largely ignored in the advances of P2P and MEC,which is related to the social relations between users.It plays a vital role in improving the efficiency and reliability of traffic offloading service.In this paper,we integrate an edge node and the nearby P2P users as a mobile P2P social network and introduce the problem of adaptive anchored(k,r)-core to maintain the stability of multiple mobile P2P networks.It aims to adaptively select and retain a set of critical users for each network,whose participation is critical to overall stability of the network,and allocate certain resource for them so that the maximum number of users of all networks will remain engaged and the traffic of cellular network can be minimized.We called the retained users as anchor vertices.To address it,we devise a peer-edge-cloud framework to achieve the adaptive allocation of resources.We also develop a similarity based onion layers anchored(k,r)-core(S-OLAK)algorithm to explore the anchor vertices.Experimental results based on a real large-scale mobile P2P data set demonstrate the effectiveness of our method.展开更多
基金Supported by the National 111 Project of China under Grant No.B07019Important National Science & Technology Specific Project:Numerical Simulation and Experimental Investigation of FPSO and Offloading System,No.2011ZX05030-006-002
文摘In order to provide a theoretical guide for choosing the material for the hawsers for the FPSO side-by-side offloading system, which is moored by the yoke system, the 3D potential flow theory and full coupled time-domain analysis are presented to study the dynamic response of the offloading system. The MingZhu FPSO offloading system in the field BZ25-1 is simulated here; and four different characteristic fiber ropes are used as the material for the hawsers. To acquire an accurate hawser line tension, the polynomial fitting method is used to calculate the nonlinear stiffness of the hawsers. By comparing the hawser lines＇ tension and the relative motion between the FPSO and the shuttle tanker, a suitable material for the hawser lines is chosen and discussed in this paper. The results indicate that the nonlinear stiffness characteristic of the fiber rope has a small effect on the relative motion of the vessels, but the hawser lines＇ tension is greatly influenced by the different characteristics of the fiber ropes. The hawser lines＇ tension with nonlinear stiffness is in accordance with the one with the upper and lower bound linear stiffness, which proves this method of fitting the fiber ropes＇ nonlinear stiffness is reasonable and reliable.
文摘计算密集型任务数量的增加导致智能移动设备(Smart Mobile Devices,SMD)计算任务过载,借助MEC(Mobile Edge Computing Servers)及利用网络中空闲边缘设备(Edge Devices,ED)可使计算能力受限的SMD将计算任务卸载到MEC和ED协作中,并基于委托信誉证明(Delegated Proof of Reputation,DPoR)共识机制增强系统的安全性。文中提出一种基于鸟群人工鱼群算法(Bird Swarm-Artificial Fish Swarm Algorithm,BS-AFSA)的区块链移动边缘计算卸载模型,将任务卸载问题转化为优化目标函数来降低计算开销。采用改进鸟群人工鱼群算法来优化任务时延和能量消耗,对算法中的行为参数进行针对性构造,并改进拥挤度因子来提高后期迭代中寻优的局部搜索精度。仿真结果表明,与其他基准算法相比,文中所提算法减少了陷入局部最优的可能性,并降低了联合卸载方案的系统总开销。
基金This work was supported by National Key Research and Development Program of China under Grant 2019YFB2101901 and 2018YFC0809803National Natural Science Foundation of China under Grant 61702364.
文摘As the rapid growth of mobile social networks,mobile peer-to-peer(P2P)communications and mobile edge computing(MEC)have been developed to reduce the traffic load and improve the computation capacity of cellular networks.However,the stability of social network is largely ignored in the advances of P2P and MEC,which is related to the social relations between users.It plays a vital role in improving the efficiency and reliability of traffic offloading service.In this paper,we integrate an edge node and the nearby P2P users as a mobile P2P social network and introduce the problem of adaptive anchored(k,r)-core to maintain the stability of multiple mobile P2P networks.It aims to adaptively select and retain a set of critical users for each network,whose participation is critical to overall stability of the network,and allocate certain resource for them so that the maximum number of users of all networks will remain engaged and the traffic of cellular network can be minimized.We called the retained users as anchor vertices.To address it,we devise a peer-edge-cloud framework to achieve the adaptive allocation of resources.We also develop a similarity based onion layers anchored(k,r)-core(S-OLAK)algorithm to explore the anchor vertices.Experimental results based on a real large-scale mobile P2P data set demonstrate the effectiveness of our method.
