As a main distributed computing system,Spark has been used to solve problems with more and more complex tasks.However,the native scheduling strategy of Spark assumes it works on a homogenized cluster,which is not so e...As a main distributed computing system,Spark has been used to solve problems with more and more complex tasks.However,the native scheduling strategy of Spark assumes it works on a homogenized cluster,which is not so effective when it comes to heterogeneous cluster.The aim of this study is looking for a more effective strategy to schedule tasks and adding it to the source code of Spark.After investigating Spark scheduling principles and mechanisms,we developed a stratifying algorithm and a node scheduling algorithm is proposed in this paper to optimize the native scheduling strategy of Spark.In this new strategy,the static level of nodes is calculated,the dynamic factors such as the length of running tasks,and CPU usage of work nodes are considered comprehensively.And through a series of comparative experiments in alienation cluster,the new strategy costs less running time and lower CPU usage rate than the original Spark strategy,which verifies that the new schedule strategy is more effective one.展开更多
对比研究了藻菌混合包埋（MI）和藻菌分层包埋SI1（藻外菌内）、SI2（藻内菌外）固定化藻菌对养殖废水中氮、磷的去除效果,以及光照、温度对3种处理脱氮去磷的影响。试验结果表明,在设计条件下处理72 h MI与SI2对氮的去除率分别为91.20%...对比研究了藻菌混合包埋（MI）和藻菌分层包埋SI1（藻外菌内）、SI2（藻内菌外）固定化藻菌对养殖废水中氮、磷的去除效果,以及光照、温度对3种处理脱氮去磷的影响。试验结果表明,在设计条件下处理72 h MI与SI2对氮的去除率分别为91.20%和90.77%,显著高于SI1。MI与SI1的去磷效果显著强于SI2,处理72 h后2者对磷的去除率分别为90.31%和84.78%,SI2仅为32.09%。当[光]照度〈6 000 lx时,SI2氮去除率在88%以上,显著高于MI与SI1;[光]照度〉6 000 lx时,SI2与MI对氮的去除率均高于89%,显著高于SI1。MI与SI1对磷的去除率在85%以上,显著高于SI2。MI、SI1、SI2去除氮、磷的最佳温度为20-30℃。展开更多
目的:探讨甲状腺超声规范化诊断及规范化报告在甲状腺结节分层管理中的价值。方法:应用2011年韩国学者Kwak提出的甲状腺超声影像数据报告系统(Thyroid Imaging Reporting and Data System,TI-RADS),回顾性分析2015年1月1日至2018年12月3...目的:探讨甲状腺超声规范化诊断及规范化报告在甲状腺结节分层管理中的价值。方法:应用2011年韩国学者Kwak提出的甲状腺超声影像数据报告系统(Thyroid Imaging Reporting and Data System,TI-RADS),回顾性分析2015年1月1日至2018年12月31日就诊于我院的11053例甲状腺疾病患者的彩色多普勒超声规范化诊断及报告,探讨甲状腺超声规范化诊断及报告系统在甲状腺结节分层管理中的价值。结果:对11053例患者共13333个结节进行规范化诊断及报告:TI-RADS I类占8.63%;TI-RADS Ⅱ类占18.50%;TI-RADS Ⅲ类占47.25%;TI-RADS IVa类11.75%;TI-RADS IVb类9.83%;TI-RADS IVc类2.32%;TI-RADS V类1.72%。其中,对632例TI-RADS≥IV类且有手术指征的患者行外科手术治疗取得病理结果。结果显示,随着TI-RADS分级增加,恶性率呈上升趋势。绘制ROC曲线后,曲线下面积为0.918,证明对于TI-RADS≥Ⅳ类甲状腺结节,该分层管理诊断方法具有一定价值。结论:甲状腺超声规范化诊断及报告,为临床诊断和治疗提供客观的影像学依据,有效将甲状腺疾病患者进行分层管理,可达到合理分流、有的放矢、精准诊疗的效果。展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant No.61472248,61772337)the SJTU-Shanghai Songheng Content Analysis Joint Lab.
文摘As a main distributed computing system,Spark has been used to solve problems with more and more complex tasks.However,the native scheduling strategy of Spark assumes it works on a homogenized cluster,which is not so effective when it comes to heterogeneous cluster.The aim of this study is looking for a more effective strategy to schedule tasks and adding it to the source code of Spark.After investigating Spark scheduling principles and mechanisms,we developed a stratifying algorithm and a node scheduling algorithm is proposed in this paper to optimize the native scheduling strategy of Spark.In this new strategy,the static level of nodes is calculated,the dynamic factors such as the length of running tasks,and CPU usage of work nodes are considered comprehensively.And through a series of comparative experiments in alienation cluster,the new strategy costs less running time and lower CPU usage rate than the original Spark strategy,which verifies that the new schedule strategy is more effective one.
