This paper presents a new finite element model updating method for estimating structural parameters and detecting structural damage location and severity based on the structural responses(output-only data).The method ...This paper presents a new finite element model updating method for estimating structural parameters and detecting structural damage location and severity based on the structural responses(output-only data).The method uses the sensitivity relation of transmissibility data through a least-squares algorithm and appropriate normalization of the extracted equations.The proposed transmissibility-based sensitivity equation produces a more significant number of equations than the sensitivity equations based on the frequency response function(FRF),which can estimate the structural parameters with higher accuracy.The abilities of the proposed method are assessed by using numerical data of a two-story two-bay frame model and a plate structure model.In evaluating different damage cases,the number,location,and stiffness reduction of the damaged elements and the severity of the simulated damage have been accurately identified.The reliability and stability of the presented method against measurement and modeling errors are examined using error-contaminated data.The parameter estimation results prove the method’s capabilities as an accurate model updating algorithm.展开更多
为解决一种先进的新型机载传感器——嵌入式大气数据传感器(flush air data sensing,FADS)的故障诊断问题,提出了一种新的方法。基于CFD软件和空气动力学知识获得数据库并建立高精度FADS模型。以系统数学模型为基础,经过严格的公式推导...为解决一种先进的新型机载传感器——嵌入式大气数据传感器(flush air data sensing,FADS)的故障诊断问题,提出了一种新的方法。基于CFD软件和空气动力学知识获得数据库并建立高精度FADS模型。以系统数学模型为基础,经过严格的公式推导得到故障情况下各组信号的分布特点。为了降低虚警率,基于统计学知识设计了告警次数阈值。为了验证新提出方法的有效性,在不同方差的测量噪声情况下分别将所提方法与以往该领域中被广泛采纳的基于奇偶方程和卡方χ2分布的2种传统方法进行了对比与分析。结果表明,与以往FADS系统的故障诊断方法相比,新提出方法具有更高的诊断精度和更强的抗干扰性。展开更多
Actuator fault detection for sampled-data systems was investigated from the viewpoint of jump systems. With the aid of a prior frequency information on fault, such a problem is converted to an augmented H_∞ filtering...Actuator fault detection for sampled-data systems was investigated from the viewpoint of jump systems. With the aid of a prior frequency information on fault, such a problem is converted to an augmented H_∞ filtering problem. A simple state-space approach is then proposed to deal with sampled-data actuator fault detection problem. Compared with the existed approaches, the proposed approach allows parameters of the sampled-data system being time-varying with consideration of measurement noise.展开更多
工业控制系统(industrial control system,ICS)入侵检测模型近年来愈加复杂,参数优化愈加困难,传统单分类器模型表现出明显的局限性。针对该问题,提出一种基于多分类器集成的ICS入侵检测算法,借鉴“分而治之”的思路将高维复杂入侵检测...工业控制系统(industrial control system,ICS)入侵检测模型近年来愈加复杂,参数优化愈加困难,传统单分类器模型表现出明显的局限性。针对该问题,提出一种基于多分类器集成的ICS入侵检测算法,借鉴“分而治之”的思路将高维复杂入侵检测问题分解为多个简单子问题,使用单分类器模型对每个子问题进行分析并获取最优分类,最后采用改进Bagging完成各个分类器结果的融合。同时针对样本不均衡问题,在预处理阶段提出改进的少数样本合成技术(improved synthetic minority over-sampling technique,ImSMOTE)构建平衡数据集。采用密西西比州立大学(Mississippi State University,MSU)的天然气管道测试平台SCADA系统记录的真实数据开展实验,结果表明所提方法能够获得较高的入侵检测准确率,同时少数类别的误检率明显降低,能够有效提升ICS系统的安全性和可靠性。展开更多
文摘This paper presents a new finite element model updating method for estimating structural parameters and detecting structural damage location and severity based on the structural responses(output-only data).The method uses the sensitivity relation of transmissibility data through a least-squares algorithm and appropriate normalization of the extracted equations.The proposed transmissibility-based sensitivity equation produces a more significant number of equations than the sensitivity equations based on the frequency response function(FRF),which can estimate the structural parameters with higher accuracy.The abilities of the proposed method are assessed by using numerical data of a two-story two-bay frame model and a plate structure model.In evaluating different damage cases,the number,location,and stiffness reduction of the damaged elements and the severity of the simulated damage have been accurately identified.The reliability and stability of the presented method against measurement and modeling errors are examined using error-contaminated data.The parameter estimation results prove the method’s capabilities as an accurate model updating algorithm.
文摘为解决一种先进的新型机载传感器——嵌入式大气数据传感器(flush air data sensing,FADS)的故障诊断问题,提出了一种新的方法。基于CFD软件和空气动力学知识获得数据库并建立高精度FADS模型。以系统数学模型为基础,经过严格的公式推导得到故障情况下各组信号的分布特点。为了降低虚警率,基于统计学知识设计了告警次数阈值。为了验证新提出方法的有效性,在不同方差的测量噪声情况下分别将所提方法与以往该领域中被广泛采纳的基于奇偶方程和卡方χ2分布的2种传统方法进行了对比与分析。结果表明,与以往FADS系统的故障诊断方法相比,新提出方法具有更高的诊断精度和更强的抗干扰性。
文摘Actuator fault detection for sampled-data systems was investigated from the viewpoint of jump systems. With the aid of a prior frequency information on fault, such a problem is converted to an augmented H_∞ filtering problem. A simple state-space approach is then proposed to deal with sampled-data actuator fault detection problem. Compared with the existed approaches, the proposed approach allows parameters of the sampled-data system being time-varying with consideration of measurement noise.
文摘工业控制系统(industrial control system,ICS)入侵检测模型近年来愈加复杂,参数优化愈加困难,传统单分类器模型表现出明显的局限性。针对该问题,提出一种基于多分类器集成的ICS入侵检测算法,借鉴“分而治之”的思路将高维复杂入侵检测问题分解为多个简单子问题,使用单分类器模型对每个子问题进行分析并获取最优分类,最后采用改进Bagging完成各个分类器结果的融合。同时针对样本不均衡问题,在预处理阶段提出改进的少数样本合成技术(improved synthetic minority over-sampling technique,ImSMOTE)构建平衡数据集。采用密西西比州立大学(Mississippi State University,MSU)的天然气管道测试平台SCADA系统记录的真实数据开展实验,结果表明所提方法能够获得较高的入侵检测准确率,同时少数类别的误检率明显降低,能够有效提升ICS系统的安全性和可靠性。
