基于机组同调性的影响因素,提出一种新的鼠笼型风电场动态等值建模方法。该方法通过采集不同工况和短路故障类型组合下风力发电机的转速向量,利用two-step法对风电机组聚合分类,并根据Fisher判别分析进行聚类结果的显著性检验。在综合...基于机组同调性的影响因素,提出一种新的鼠笼型风电场动态等值建模方法。该方法通过采集不同工况和短路故障类型组合下风力发电机的转速向量,利用two-step法对风电机组聚合分类,并根据Fisher判别分析进行聚类结果的显著性检验。在综合考虑风电场全年风资源统计信息和系统侧不同类型故障发生比例的基础上,以概率最大的机群划分结果,建立风电场概率等值模型。使用DIgSILENT Power Factory平台进行风电场机电暂态仿真,并与传统等值模型和详细模型对比。仿真结果表明,该文提出以转速向量作为分群判据是合理的,所建立的风电场概率等值模型能较全面表征风电场全年的运行外特性,具有重要的工程应用价值。展开更多
Objective:The global aim to lower preterm birth rates has been hampered by the insufficient and incomplete understanding of its etiology,classification,and diagnosis.This study was designed to evaluate the association...Objective:The global aim to lower preterm birth rates has been hampered by the insufficient and incomplete understanding of its etiology,classification,and diagnosis.This study was designed to evaluate the association of phenotypically classified preterm syndromes with neonatal outcomes;to what extent would these outcomes be modified after the obstetric interventions,including use of glucocorticoid,magnesium sulfate,and progesterone.Methods:This was a retrospective cohort study conducted at Tongji Hospital(composed of Main Branch,Optical Valley Branch and Sino-French New City Branch)in Wuhan.A total of 900 pregnant women and 1064 neonates were retrospectively enrolled.The outcomes were the distribution of different phenotypes among parturition signs and pathway to delivery,the association of phenotypically classified clusters with short-term unfavorable neonatal outcomes,and to what extent these outcomes could be modified by obstetric interventions.Results:Eight clusters were identified using two-step cluster analysis,including premature rupture of fetal membranes(PPROM)phenotype,abnormal amniotic fluid(AF)phenotype,placenta previa phenotype,mixed condition phenotype,fetal distress phenotype,preeclampsia-eclampsia&hemolysis,elevated liver enzymes,and low platelets syndrome(PE-E&HELLP)phenotype,multiple fetus phenotype,and no main condition phenotype.Except for no main condition phenotype,the other phenotypes were associated with one or more complications,which conforms to the clinical practice.Compared with no main condition phenotype,some phenotypes were significantly associated with short-term adverse neonatal outcomes.Abnormal AF phenotype,mixed condition phenotype,PE-E&HELLP phenotype,and multiple fetus phenotype were risk factors for neonatal small-for gestation age(SGA);placenta previa phenotype was not associated with adverse outcomes except low APGAR score being 0-7 at one min;mixed condition phenotype was associated with low APGAR scores,SGA,mechanical ventilation,and gradeⅢ-Ⅳintraventricular hemorrh展开更多
文摘基于机组同调性的影响因素,提出一种新的鼠笼型风电场动态等值建模方法。该方法通过采集不同工况和短路故障类型组合下风力发电机的转速向量,利用two-step法对风电机组聚合分类,并根据Fisher判别分析进行聚类结果的显著性检验。在综合考虑风电场全年风资源统计信息和系统侧不同类型故障发生比例的基础上,以概率最大的机群划分结果,建立风电场概率等值模型。使用DIgSILENT Power Factory平台进行风电场机电暂态仿真,并与传统等值模型和详细模型对比。仿真结果表明,该文提出以转速向量作为分群判据是合理的,所建立的风电场概率等值模型能较全面表征风电场全年的运行外特性,具有重要的工程应用价值。
基金supported by the National Science Foundation of China(No.81873843)the National Science and Technology Pillar Program of China during the Twelfth Five-Year Plan Period(No.2014BAI05B05)the Fundamental Research Funds for the Central Universities(Nos.2017KFYXJJ102,2019KFYXKJC053).
文摘Objective:The global aim to lower preterm birth rates has been hampered by the insufficient and incomplete understanding of its etiology,classification,and diagnosis.This study was designed to evaluate the association of phenotypically classified preterm syndromes with neonatal outcomes;to what extent would these outcomes be modified after the obstetric interventions,including use of glucocorticoid,magnesium sulfate,and progesterone.Methods:This was a retrospective cohort study conducted at Tongji Hospital(composed of Main Branch,Optical Valley Branch and Sino-French New City Branch)in Wuhan.A total of 900 pregnant women and 1064 neonates were retrospectively enrolled.The outcomes were the distribution of different phenotypes among parturition signs and pathway to delivery,the association of phenotypically classified clusters with short-term unfavorable neonatal outcomes,and to what extent these outcomes could be modified by obstetric interventions.Results:Eight clusters were identified using two-step cluster analysis,including premature rupture of fetal membranes(PPROM)phenotype,abnormal amniotic fluid(AF)phenotype,placenta previa phenotype,mixed condition phenotype,fetal distress phenotype,preeclampsia-eclampsia&hemolysis,elevated liver enzymes,and low platelets syndrome(PE-E&HELLP)phenotype,multiple fetus phenotype,and no main condition phenotype.Except for no main condition phenotype,the other phenotypes were associated with one or more complications,which conforms to the clinical practice.Compared with no main condition phenotype,some phenotypes were significantly associated with short-term adverse neonatal outcomes.Abnormal AF phenotype,mixed condition phenotype,PE-E&HELLP phenotype,and multiple fetus phenotype were risk factors for neonatal small-for gestation age(SGA);placenta previa phenotype was not associated with adverse outcomes except low APGAR score being 0-7 at one min;mixed condition phenotype was associated with low APGAR scores,SGA,mechanical ventilation,and gradeⅢ-Ⅳintraventricular hemorrh