A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the deve...A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies gradually.In the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after solidification.In this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder amount.All the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified slurry.Retention rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour performance.The unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.展开更多
为了探索便携交换网络的演化规律,研究其网络行为预测中的链路预测问题。便携交换网络具有节点移动性、节点间间歇性连接、高延迟等特点,其链路预测面临的挑战是节点相遇的机会性和拓扑的时变性,获得其高质量链路预测的关键是如何较全...为了探索便携交换网络的演化规律,研究其网络行为预测中的链路预测问题。便携交换网络具有节点移动性、节点间间歇性连接、高延迟等特点,其链路预测面临的挑战是节点相遇的机会性和拓扑的时变性,获得其高质量链路预测的关键是如何较全面地获取节点的属性。作者提出基于学习自动机和萤火虫算法的链路预测方法(link prediction approach for pocket switched network based on firefly algorithm,FA-LP)。采用学习自动机对节点进行自适应聚类,完成网络的社区划分;定义社区属性影响系数和移动行为影响系数,构建反映便携交换网络社区属性、节点移动性和节点间间歇性连接的相似性指标;将该指标与CN、RA、AA等指标融合,得到便携交换网络的相似性指标向量;借助差分整合移动平均自回归模型的时间序列分析能力,提取相似性指标向量序列的演化规律;采用萤火虫算法优化所构建的二分类器,预测节点对下一时刻的连接状态。INFOCOM2006和MIT两个真实数据下的实验结果表明,与受限玻尔兹曼机、弱评估器等方法相比,FA-LP具有更高的准确率和更好的稳定性。展开更多
基金financially supported by the Science and Technology Commission Foundation of Shanghai(Grant Nos.22DZ1208903,20DZ2251900)the National Natural Science Foundation of China(Grant No.51679134)。
文摘A new scour countermeasure using solidified slurry for offshore foundation has been proposed recently.Fluidized solidified slurry is pumped to seabed area around foundation for scour protection or pumped into the developed scour holes for scour repair as the fluidized material solidifies gradually.In the pumping operation and solidification,the engineering behaviors of solidified slurry require to be considered synthetically for the reliable application in scour repair and protection of ocean engineering such as the pumpability related flow value,flow diffusion behavior related rheological property,anti-scour performance related retention rate in solidification and bearing capacity related strength property after solidification.In this study,a series of laboratory tests are conducted to investigate the effects of mix proportion(initial water content and binder content)on the flow value,rheological properties,density,retention rate of solidified slurry and unconfined compressive strength(UCS).The results reveal that the flow value increases with the water content and decreases with the binder amount.All the solidified slurry exhibits Bingham plastic behavior when the shear rate is larger than 5 s^(-1).The Bingham model has been employed to fit the rheology test results,and empirical formulas for obtaining the density,yield stress and viscosity are established,providing scientific support for the numerical assessment of flow and diffusion of solidified slurry.Retention rate of solidified slurry decreases with the water flow velocity and flow value,which means the pumpability of solidified slurry is contrary to anti-scour performance.The unconfined compressive strength after solidification reduces as the water content increases and binder content decreases.A design and application procedure of solidified soil for scour repair and protection is also proposed for engineering reference.
文摘为了探索便携交换网络的演化规律,研究其网络行为预测中的链路预测问题。便携交换网络具有节点移动性、节点间间歇性连接、高延迟等特点,其链路预测面临的挑战是节点相遇的机会性和拓扑的时变性,获得其高质量链路预测的关键是如何较全面地获取节点的属性。作者提出基于学习自动机和萤火虫算法的链路预测方法(link prediction approach for pocket switched network based on firefly algorithm,FA-LP)。采用学习自动机对节点进行自适应聚类,完成网络的社区划分;定义社区属性影响系数和移动行为影响系数,构建反映便携交换网络社区属性、节点移动性和节点间间歇性连接的相似性指标;将该指标与CN、RA、AA等指标融合,得到便携交换网络的相似性指标向量;借助差分整合移动平均自回归模型的时间序列分析能力,提取相似性指标向量序列的演化规律;采用萤火虫算法优化所构建的二分类器,预测节点对下一时刻的连接状态。INFOCOM2006和MIT两个真实数据下的实验结果表明,与受限玻尔兹曼机、弱评估器等方法相比,FA-LP具有更高的准确率和更好的稳定性。
