在临床医学和流行病学研究中,由于研究时间和随访的限制,生存数据通常存在右删失,因此限制均值寿命常用于评估实际研究中的治疗效应。本文结合协变量修正和删失数据处理方法,分析非随机化分组在随机删失和相依删失条件下的治疗效应差异...在临床医学和流行病学研究中,由于研究时间和随访的限制,生存数据通常存在右删失,因此限制均值寿命常用于评估实际研究中的治疗效应。本文结合协变量修正和删失数据处理方法,分析非随机化分组在随机删失和相依删失条件下的治疗效应差异问题。首先,利用倾向得分协变量修正法消除混杂影响;然后,采用逆概率删失加权方法调整相依删失引起的偏差,并考虑删失时间与协变量及基线风险函数的关系。最后,将本文提出的方法应用于70岁以上乳腺癌浸润性导管癌女性患者的两种治疗策略的效果差异分析。In clinical medicine and epidemiology research, due to limitations in study duration and follow up, survival data is often subject to right censoring, making restricted mean survival time (RMST) a common measure for assessing treatment effects in practical studies. This paper combines covariate adjustment and methods for handling censored data to analyze treatment effect differences in non-randomized groups under conditions of random and dependent censoring. First, propensity score covariate adjustment is used to eliminate confounding effects. Then, inverse probability of censoring weighting (IPCW) is applied to adjust for biases caused by dependent censoring, taking into account the relationship between censoring time, covariates, and baseline hazard function. Finally, the proposed method is applied to analyze the effect differences between two treatment strategies for women over 70 years old with invasive ductal carcinoma of the breast.展开更多
螺栓在输电线路中起着至关重要的作用,一旦某个螺栓被损坏,就可能出现漏电及线路松动等隐患,影响整个电路的安全。为快速准确地检测螺栓,提高巡检效率,保障输电线路的稳定运行,提出了一种基于改进YOLOv7网络的输电线螺栓检测方法。首先,...螺栓在输电线路中起着至关重要的作用,一旦某个螺栓被损坏,就可能出现漏电及线路松动等隐患,影响整个电路的安全。为快速准确地检测螺栓,提高巡检效率,保障输电线路的稳定运行,提出了一种基于改进YOLOv7网络的输电线螺栓检测方法。首先,在YOLOv7的头部层中集成了注意力机制,加强了骨干特征提取,使网络能够专注于相关的目标对象;其次,提出用SiLU(Sigmoid Linear Unit)激活函数取代YOLOv7网络中原有的激活函数,提高螺栓的检测性能。实验结果表明,mAP(平均精确率均值)为94%,F_(1)-Score(F_(1)值)为86%,Precision(精确率)为88%,Recall(召回率)为84%,平均检测时间为0.025 s,超过了其他模型。改进后的YOLOv7模型具有出色的螺栓检测精度,使巡检机器人能够在输电线中有效地检测螺栓。展开更多
文摘在临床医学和流行病学研究中,由于研究时间和随访的限制,生存数据通常存在右删失,因此限制均值寿命常用于评估实际研究中的治疗效应。本文结合协变量修正和删失数据处理方法,分析非随机化分组在随机删失和相依删失条件下的治疗效应差异问题。首先,利用倾向得分协变量修正法消除混杂影响;然后,采用逆概率删失加权方法调整相依删失引起的偏差,并考虑删失时间与协变量及基线风险函数的关系。最后,将本文提出的方法应用于70岁以上乳腺癌浸润性导管癌女性患者的两种治疗策略的效果差异分析。In clinical medicine and epidemiology research, due to limitations in study duration and follow up, survival data is often subject to right censoring, making restricted mean survival time (RMST) a common measure for assessing treatment effects in practical studies. This paper combines covariate adjustment and methods for handling censored data to analyze treatment effect differences in non-randomized groups under conditions of random and dependent censoring. First, propensity score covariate adjustment is used to eliminate confounding effects. Then, inverse probability of censoring weighting (IPCW) is applied to adjust for biases caused by dependent censoring, taking into account the relationship between censoring time, covariates, and baseline hazard function. Finally, the proposed method is applied to analyze the effect differences between two treatment strategies for women over 70 years old with invasive ductal carcinoma of the breast.
文摘螺栓在输电线路中起着至关重要的作用,一旦某个螺栓被损坏,就可能出现漏电及线路松动等隐患,影响整个电路的安全。为快速准确地检测螺栓,提高巡检效率,保障输电线路的稳定运行,提出了一种基于改进YOLOv7网络的输电线螺栓检测方法。首先,在YOLOv7的头部层中集成了注意力机制,加强了骨干特征提取,使网络能够专注于相关的目标对象;其次,提出用SiLU(Sigmoid Linear Unit)激活函数取代YOLOv7网络中原有的激活函数,提高螺栓的检测性能。实验结果表明,mAP(平均精确率均值)为94%,F_(1)-Score(F_(1)值)为86%,Precision(精确率)为88%,Recall(召回率)为84%,平均检测时间为0.025 s,超过了其他模型。改进后的YOLOv7模型具有出色的螺栓检测精度,使巡检机器人能够在输电线中有效地检测螺栓。
