针对传统互联网调度无法满足工业业务QoS(Quality of Service)需求的问题,文中在基于SDN的新型网络架构上提出了一种改进的路由算法,并对其中使用的Floodlight控制器模块进行扩展与修改。根据信息收集单元模块提供的带宽信息与链路发现...针对传统互联网调度无法满足工业业务QoS(Quality of Service)需求的问题,文中在基于SDN的新型网络架构上提出了一种改进的路由算法,并对其中使用的Floodlight控制器模块进行扩展与修改。根据信息收集单元模块提供的带宽信息与链路发现模块提供的网络拓扑信息,路由计算模块对进入的数据流计算出更优化的最短路径。仿真实验结果表明,改进后的路由算法有效降低了数据的传输时延,增强了网络的稳定性。展开更多
针对毫米波雷达数据均匀性差,数据量小,噪点多等问题,提出一种基于DBSCAN(density-based spatial clustering of applications with noise)的雷达自适应聚类算法。改进算法能够根据K近邻距离和目标反射截面自适应调整聚类半径。首先给...针对毫米波雷达数据均匀性差,数据量小,噪点多等问题,提出一种基于DBSCAN(density-based spatial clustering of applications with noise)的雷达自适应聚类算法。改进算法能够根据K近邻距离和目标反射截面自适应调整聚类半径。首先给出一种聚类半径根据K近邻距离动态调整的机制:目标第K个近邻的距离与阈值相比较,以确定阈值半径取值。再提取雷达提供的目标反射截面,基于该值计算目标假象半径作为聚类半径的补充量。实现根据目标反射截面与数据稀疏程度自适应聚类的效果。将改进算法与不同参数的DBSCAN聚类算法在真实雷达点云数据进行实验对比。相较于选取合适参数的DBSCAN算法,改进算法能够更好适应毫米波雷达点云特征,对行人目标识别准确率提高4.18%,对车辆目标识别准确率提高5.63%。展开更多
Both numerical calculation and model test are important techniques to study and forecast the dynamic responses of the floating offshore wind turbine(FOWT). However, both the methods have their own limitations at prese...Both numerical calculation and model test are important techniques to study and forecast the dynamic responses of the floating offshore wind turbine(FOWT). However, both the methods have their own limitations at present. In this study, the dynamic responses of a 5 MW OC3 spar-type floating wind turbine designed for a water depth of 200 m are numerically investigated and validated by a 1:50 scaled model test. Moreover, the discrepancies between the numerical calculations and model tests are obtained and discussed. According to the discussions, it is found that the surge and pitch are coupled with the mooring tensions, but the heave is independent of them. Surge and pitch are mainly induced by wave under wind wave conditions. Wind and current will induce the low-frequency average responses, while wave will induce the fluctuation ranges of the responses. In addition, wave will induce the wavefrequency responses but wind and current will restrain the ranges of the responses.展开更多
流行病学及实验感染证明,猪蛔虫(Ascaris suum Geeze 1782)与人蛔虫(A.lum-bricoides L. 1758)有明显的不同,在形态学上是否有种的差异仍是一个有争议的问题。鉴于此,我们用扫描电镜先对猪蛔虫的外部结构作了初步观察,以供今后与人蛔虫...流行病学及实验感染证明,猪蛔虫(Ascaris suum Geeze 1782)与人蛔虫(A.lum-bricoides L. 1758)有明显的不同,在形态学上是否有种的差异仍是一个有争议的问题。鉴于此,我们用扫描电镜先对猪蛔虫的外部结构作了初步观察,以供今后与人蛔虫加以比较。展开更多
文摘针对传统互联网调度无法满足工业业务QoS(Quality of Service)需求的问题,文中在基于SDN的新型网络架构上提出了一种改进的路由算法,并对其中使用的Floodlight控制器模块进行扩展与修改。根据信息收集单元模块提供的带宽信息与链路发现模块提供的网络拓扑信息,路由计算模块对进入的数据流计算出更优化的最短路径。仿真实验结果表明,改进后的路由算法有效降低了数据的传输时延,增强了网络的稳定性。
文摘针对毫米波雷达数据均匀性差,数据量小,噪点多等问题,提出一种基于DBSCAN(density-based spatial clustering of applications with noise)的雷达自适应聚类算法。改进算法能够根据K近邻距离和目标反射截面自适应调整聚类半径。首先给出一种聚类半径根据K近邻距离动态调整的机制:目标第K个近邻的距离与阈值相比较,以确定阈值半径取值。再提取雷达提供的目标反射截面,基于该值计算目标假象半径作为聚类半径的补充量。实现根据目标反射截面与数据稀疏程度自适应聚类的效果。将改进算法与不同参数的DBSCAN聚类算法在真实雷达点云数据进行实验对比。相较于选取合适参数的DBSCAN算法,改进算法能够更好适应毫米波雷达点云特征,对行人目标识别准确率提高4.18%,对车辆目标识别准确率提高5.63%。
基金financially supported by the State Key Laboratory of Ocean Engineering in Shanghai Jiao Tong University and the National Science and Technology Major Project of China(Grant No.2016ZX05028-002-004)
文摘Both numerical calculation and model test are important techniques to study and forecast the dynamic responses of the floating offshore wind turbine(FOWT). However, both the methods have their own limitations at present. In this study, the dynamic responses of a 5 MW OC3 spar-type floating wind turbine designed for a water depth of 200 m are numerically investigated and validated by a 1:50 scaled model test. Moreover, the discrepancies between the numerical calculations and model tests are obtained and discussed. According to the discussions, it is found that the surge and pitch are coupled with the mooring tensions, but the heave is independent of them. Surge and pitch are mainly induced by wave under wind wave conditions. Wind and current will induce the low-frequency average responses, while wave will induce the fluctuation ranges of the responses. In addition, wave will induce the wavefrequency responses but wind and current will restrain the ranges of the responses.
