简介:摘要介绍了双曲线和指数曲线沉降预测法,以江苏南部某湖相软土路基处理工程实测的沉降数据为基础,建立双曲线和指数曲线预报模型,对沉降量进行预测,并对两种方法的预测结果进行对比分析。结果表明,两种方法的预测结果与实测值较为接近,指数曲线法的精确度更高,是预测软基沉降量的一种较为理想的方法。
简介:目的探讨股骨头坏死(FHN)区域夹角/面积的比值在预测非创伤性缺血性股骨头坏死患者出现股骨头塌陷的敏感度及特异度。方法收集31例37髋FHN患者进行长期随访,测量其坏死面积及夹角,使用受试者工作特征曲线(ROC)法评价以上患者出现股骨头塌陷的敏感度及特异度。结果37髋共有11髋出现股骨头塌陷(29.7%);与未塌陷组(对照组)比较,塌陷组的坏死区域夹角及坏死面积均大于对照组(P=0.001、0.001),且夹角/面积比值同样明显大于对照组(P〈0.001);夹角对应的曲线下面积(AUC)为0.772,95%可信区间(CI)为(0.613,0.932),面积对应的AUC为0.724,95%CI为(0.516,0.814),而夹角/面积对应的AUC为0.785,95%CI为(0.627,0.944)。夹角、面积及夹角/面积比值三者均与股骨头塌陷存在显著相关性(P值分别为0.008、0.019及0.005);当夹角/面积取值为1.895(108°/57%)时,该比值预测股骨头塌陷的敏感度为97.5%,特异度为98.4%,高于而夹角对应的96.3%及87.4且高于面积对应为的76.4%及92.5%。结论股骨头坏死区域夹角为108°或坏死面积为57%时,需高度警惕股骨头出现塌陷的可能;夹角/面积比值在预测股骨头塌陷的敏感度及特异度均优于夹角或面积单一指标。
简介:Objective:Todeterminetheclinicalserumlevelsofcarcinoembryonicantigen(CEA)andcarbohydrateantigen19-9(CA19-9),individuallyandincombination,forthediagnosisof50healthysubjectsand150casesofesophageal,gastric,andcoloncancers.Methods:Thesensitivitiesofthetwomarkerswerecomparedindividuallyandincombination,withspecificitysetat100%.Receiveroperatingcharacteristic(ROC)curveswereplotted.Results:SerumCEAlevelsweresignificantlyhigherincancerpatientsthaninthecontrolgroup.ThesensitivityofCEAwasdetermined:inesophagealcancer,sensitivity=28%,negativepredictivevalue(NPV)=61.72%,andAUC=0.742(SE=0.05),withasignificancelevelofP<0.0001;ingastriccancer,sensitivity=30%,NPV=58.82%,andAUC=0.734(SE=0.05),withasignificancelevelofP<0.0001;incoloncancer,sensitivity=74%,NPV=79.36%,andAUC=0.856(SE=0.04),withasignificancelevelofP<0.0001.ThesensitivityofCA19-9wasalsoevaluated:inesophagealcancer,sensitivity=18%,NPV=54.94%,andAUC=0.573(SE=0.05),withasignificancelevelofP=0.2054.Ingastriccancer,sensitivity=42%,NPV=63.29%,andAUC=0.679(SE=0.05),withasignificancelevelofP<0.0011.Incoloncancer,sensitivity=26%,NPV=57.47%,andAUC=0.580(SE=0.05),withasignificancelevelofP=0.1670.ThefollowingwerethesensitivitiesofCEA/CA19-9combined:inesophagealcancer,sensitivity=42%,NPV=63.29%,SE=0.078(95%CI:0.0159-0.322);gastriccancer,sensitivity=58%,NPV=70.42%,SE=0.072(95%CI:-0.0866-0.198);andcoloncancer,sensitivity=72%,NPV=78.12%,SE=0.070(95%CI:0.137-0.415).Conclusion:CEAexhibitedthehighestsensitivityforcoloncancer,andCA19-9exhibitedthehighestsensitivityforgastriccancer.Combinedanalysisindicatedanincreaseindiagnosticsensitivityinesophagealandgastriccancercomparedwiththatincoloncancer.
简介:提出了点集Bézier曲线的概念,给出了点集Bézier曲线的性质及细分算法.按照点集算术的定义,当点集是长方形闭域或圆盘时,点集Bézier曲线就是区间Bézier曲线或圆盘Bézier曲线,因此,点集Bézier曲线是对区间Bézier曲线和圆盘Bézier曲线的推广.