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Chinese Journal of Aeronautics 2018年第3期31卷 514-528页

作者： Changhua HU Hong PEI Zhaoqiang WANG xiaosheng si Zhengxin ZHANG College of Science High-Tech Institute of Xi'an

As the key part of Prognostics and Health Management（PHM）, Remaining Useful Life（RUL） estimation has been extensively investigated in recent years. Current RUL estimation studies considering the intervention of imperfect maintenance activities usually assumed that maintenance activities have a single influence on the degradation level or degradation rate, but not on *** at this problem, this paper proposes a new degradation modeling and RUL estimation method taking the influence of imperfect maintenance activities on both the degradation level and the degradation rate into account. Toward this end, a stochastic degradation model considering imperfect maintenance activities is firstly constructed based on the diffusion process. Then, the Probability Density Function（PDF） of the RUL is derived by the convolution operator under the concept of First Hitting Time（FHT）. To implement the proposed RUL estimation method,the Maximum Likelihood Estimation（MLE） is utilized to estimate the degradation related parameters based on the Condition Monitoring（CM） data, while the Bayesian method is utilized to estimate the maintenance related parameters based on the maintenance data. Finally, a numerical example and a practical case study are provided to demonstrate the superiority of the proposed method. The experimental results show that the proposed method could greatly improve the RUL estimation accuracy for the degrading equipment subjected to imperfect maintenance activities.

关键词： Convolution operator Diffusion process First hitting time Imperfect maintenance Remaining useful life

A joint order-replacement policy for deteriorating components with reliability constraint

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Science China(Information Sciences) 2021年第8期64卷 241-243页

作者： xiaosheng si Changhua HU Tianmei LI Qi ZHANG Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'an Jiaotong University Department of Automation Rocket Force University of Engineering

Dear editor,Condition-based maintenance(CBM) is a popular maintenance program for degrading components and can recommend maintenance decisions based on the condition monitoring(CM) information [1]. In CBM applications, a widely adopted assumption is that spare parts are always available or can be delivered without any lead time. However,

关键词： A joint order-replacement policy for deteriorating components with reliability constraint

Degradation data-driven approach for remaining useful life estimation

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Journal of Systems Engineering and Electronics 2013年第1期24卷 173-182页

作者： Zhiliang Fan Guangbin Liu xiaosheng si Qi Zhang Qinghua Zhang Department of Automation The Second Artillery Engineering University Department of Automation Tsinghua University Guangdong University of Petrochemical Technology

Remaining useful life （RUL） estimation is termed as one of the key issues in prognostics and health management （PHM）. To achieve RUL estimation for individual equipment, we present a degradation data-driven RUL estimation approach under the collaboration between Bayesian updating and expectation maximization （EM） algorithm. Firstly, we utilize an exponential-like degradation model to describe equipment degradation process and update stochastic parameters in the model via Bayesian approach. Based on the Bayesian updating results, both probability distribution of the RUL and its point estimation can be derived. Secondly, based on the monitored degradation data to date, we give a parameter estimation approach for non-stochastic parameters in the degradation model and prove that the obtained estimation is unique and optimal in each iteration. Finally, a numerical example and a practical case study for global positioning system （GPS） receiver are provided to show that the presented approach can model degradation process and achieve RUL estimation effectively and generate better results than a previously reported approach in literature.

关键词： reliability degradation remaining useful life (RUL) prognostics global positioning system (GPS).

采用滑动窗口与克里金插值算法的复杂系统可靠性评估方法

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西安交通大学学报 2023年第4期57卷 171-179页

作者：叶爽怡扈晓翔司小胜袁勃西北工业大学自动化学院西安710129 火箭军工程大学导弹工程学院西安710025 西安微电子技术研究所西安710065

针对传统的状态权重分配方法造成历史时刻权重过大的问题,提出一种采用滑动窗口与克里金插值算法的复杂系统可靠性评估方法。利用滑动窗口模型,基于任何给定的窗口大小的移动平均误差都会随着接近时间序列的实际窗口大小而减小的思想,... 详细信息

针对传统的状态权重分配方法造成历史时刻权重过大的问题,提出一种采用滑动窗口与克里金插值算法的复杂系统可靠性评估方法。利用滑动窗口模型,基于任何给定的窗口大小的移动平均误差都会随着接近时间序列的实际窗口大小而减小的思想,确定最优的滑动窗口大小,对状态权重在线更新;借助Kriging的思想,对滑动窗口内安全性状态的权重进行重新自适应调整;使用证据推理算法融合滑动窗口内安全性状态的自适应权重获取复杂系统整体的可靠性评估结果。采用轴承的退化数据进行验证,实验结果表明:与提取水平方向和竖直方向有效值的方法进行对比,所提方法得到了更加综合直观的结果;传统的状态权重分配方法均方误差为0.0281,所提方法的均方误差为0.0167,均方误差更小,所提方法更有效。

关键词：复杂系统滑动窗口克里金插值证据推理可靠性评估

多源传感监测线性退化设备数模联动的剩余寿命预测方法

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航空学报 2023年第8期44卷 89-107页

作者：李天梅司小胜张建勋火箭军工程大学智剑实验室西安710025

随着先进传感与监测技术的快速发展,实时获取随机退化设备的多源传感监测数据已成为现实,如何有效融合多源传感监测数据以实现随机退化设备剩余寿命的精准预测成为剩余寿命预测领域的研究前沿。针对多源传感监测的线性随机退化设备,提... 详细信息

随着先进传感与监测技术的快速发展,实时获取随机退化设备的多源传感监测数据已成为现实,如何有效融合多源传感监测数据以实现随机退化设备剩余寿命的精准预测成为剩余寿命预测领域的研究前沿。针对多源传感监测的线性随机退化设备,提出了一种考虑随机失效阈值的数模联动剩余寿命预测新方法。该方法在离线训练过程中,基于多源传感历史数据提取的复合健康指标及据此线性随机退化建模预测的寿命,构建综合寿命预测值与设备实际寿命的均方误差及寿命预测方差的优化目标函数,形成复合健康指标提取与随机退化建模的反馈闭环,对多源传感器融合系数和复合健康指标对应的随机失效阈值分布参数进行优化调整,以实现复合健康指标提取与随机退化建模的自动匹配,即数模联动。在线预测时,根据提出的数模联动方法,融合实际运行设备的多源传感监测数据以获取复合健康指标,然后采用随机模型对其演变过程进行建模。同时,为使模型实时反映设备当前状况,提出了一种退化模型参数的贝叶斯更新方法,在此基础上基于首达时间得到了考虑设备失效阈值随机性的剩余寿命概率分布。最后,基于航空发动机的多源传感监测数据,验证了所提方法在改善复合健康指标特性和提高剩余寿命预测准确性方面的有效性和优势。

关键词：多源传感监测剩余寿命预测数模联动退化建模线性随机模型

采用残差网络与卷积注意力机制的设备剩余使用寿命预测方法

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西安交通大学学报 2022年第4期56卷 194-202页

作者：莫仁鹏李天梅司小胜朱旭火箭军工程大学导弹工程学院西安710025

针对以往剩余使用寿命(RUL)预测方法均等对待深层特征中具有不同重要性的空间域和通道域特征,导致大量的计算资源浪费在不重要的特征上,进而造成RUL预测值偏差过大、不能对失效设备进行及时的维护以避免潜在的安全隐患的问题,提出一种... 详细信息

针对以往剩余使用寿命(RUL)预测方法均等对待深层特征中具有不同重要性的空间域和通道域特征,导致大量的计算资源浪费在不重要的特征上,进而造成RUL预测值偏差过大、不能对失效设备进行及时的维护以避免潜在的安全隐患的问题,提出一种采用残差网络与卷积注意力机制的端到端的RUL预测方法。该方法以卷积层和池化层对原始监测信号进行浅层特征提取与压缩;利用堆叠残差模块在学习深层特征的同时,缓解梯度弥散以及网络退化现象的发生;由卷积注意力模块对设备的深层退化特征进行加权赋值,分别在其空间维度上和通道维度上强化更重要的特征并抑制相对不重要的特征,使网络的注意力集中在对RUL预测任务更关键的信息上;将加权后的特征输入到全连接网络中映射得到RUL预测值。通过PHM2012轴承数据集进行了实验验证,实验结果表明,卷积注意力和残差结构皆对改善模型的预测性能有着积极的作用,所提方法在测试轴承上的均方根误差和平均绝对误差分别为0.1079和0.0831,远低于其他对比方法。

关键词：剩余使用寿命残差网络卷积注意力端到端

基于Box-Cox变换与随机系数回归模型的非线性退化设备剩余寿命预测方法

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航空学报 2023年第11期44卷 194-206页

作者：杨保奎张建勋李慧琴司小胜火箭军工程大学智剑实验室西安710025

准确预测退化设备的剩余寿命可以为设备维护管理提供重要信息支撑,进而避免设备运行中发生计划外失效、减少设备运行维护成本。针对工程实际设备广泛存在的非线性退化现象,提出了基于Box-Cox变换与随机系数回归模型的非线性退化设备剩... 详细信息

准确预测退化设备的剩余寿命可以为设备维护管理提供重要信息支撑,进而避免设备运行中发生计划外失效、减少设备运行维护成本。针对工程实际设备广泛存在的非线性退化现象,提出了基于Box-Cox变换与随机系数回归模型的非线性退化设备剩余寿命预测方法。首先,采用Box-Cox变换对非线性退化数据进行线性化处理,在此基础上通过随机系数回归模型构建退化模型,并运用Bayesian理论与蒙特卡洛-期望最大化算法在线更新模型参数;然后,基于随机系数回归模型的特性,推导出剩余寿命的分布函数以及其点估计值;最后,通过数值仿真和锂电池实际退化数据验证所提方法的有效性。

关键词：剩余寿命 Box-Cox变换随机系数回归模型非线性退化数据蒙特卡洛-期望最大化算法

基于多源信息的隐含非线性维纳退化过程剩余寿命预测

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航空学报 2023年第12期44卷 170-187页

作者：杨家鑫唐圣金李良孙晓艳祁帅司小胜火箭军工程大学导弹工程学院西安710025 火箭军工程大学作战保障学院西安710025 火箭军装备部驻郑州军代表室郑州450000

准确的剩余寿命预测对提高系统的可靠性安全性具有重要意义。在工程应用中,经常会遇到先验退化信息不完美或缺失的情况,且线性退化模型往往难以跟踪非线性退化特征。为解决这一问题,针对带测量误差的非线性退化系统,基于隐含非线性维纳... 详细信息

准确的剩余寿命预测对提高系统的可靠性安全性具有重要意义。在工程应用中,经常会遇到先验退化信息不完美或缺失的情况,且线性退化模型往往难以跟踪非线性退化特征。为解决这一问题,针对带测量误差的非线性退化系统,基于隐含非线性维纳退化过程模型,提出了一种合理融合失效寿命数据和多源信息的剩余寿命预测方法。首先,通过理论推导,得到了隐含非线性维纳退化过程的参数估计性质与退化数据之间的关系,为合理融合多源信息提供了理论依据。其次,根据参数估计的性质,分别使用现场退化数据和历史退化数据估计2种预测情况下的模型固定参数,并使用期望最大化算法将失效寿命数据信息融入退化模型中。再次,根据现场退化数据,使用Kalman滤波算法在线更新漂移参数。最后,通过仿真实验进一步验证了参数估计的性质,并通过2个实例验证了所提方法的优越性。

关键词：剩余寿命预测测量误差隐含非线性维纳过程多源信息 Kalman滤波

Properties of collective flow and pion production in intermediate-energy heavy-ion collisions with a relativistic quantum molecular dynamics model

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Nuclear Science and Techniques 2024年第1期35卷 155-169页

作者： si-Na Wei Zhao-Qing Feng School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(***). Using the ***, the properties of collective flow and pion production were investigated systematically for nuclear reactions with various isospin asymmetries. The directed and elliptic flows of the *** are able to describe the experimental data of STAR Collaboration. The directed flow difference between free neutrons and protons was associated with the stiffness of the symmetry energy, that is, a softer symmetry energy led to a larger flow difference. For various collision energies, the ratio between the π^(-) and π^(+) yields increased with a decrease in the slope parameter of the symmetry energy. When the collision energy was 270 MeV/nucleon, the single ratio of the pion transverse momentum spectra also increased with decreasing slope parameter of the symmetry energy in both nearly symmetric and neutron-rich ***, it is difficult to constrain the stiffness of the symmetry energy with the double ratio because of the lack of threshold energy correction on the pion production.

关键词： Heavy-ion collision Collective flow Pion production Symmetry energy Relativistic mean field

Restoration of the JPEG Maximum Lossy Compressed Face Images with Hourglass Block-GAN

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Computers, Materials & Continua 2024年第3期78卷 2893-2908页

作者： Jongwook si Sungyoung Kim Department of Computer AI Convergence Engineering Kumoh National Institute of TechnologyGumi39177Korea Department of Computer Engineering Kumoh National Institute of TechnologyGumi39177Korea

In the context of high compression rates applied to Joint Photographic Experts Group(JPEG)images through lossy compression techniques,image-blocking artifacts may *** necessitates the restoration of the image to its original *** challenge lies in regenerating significantly compressed images into a state in which these become ***,this study focuses on the restoration of JPEG images subjected to substantial degradation caused by maximum lossy compression using Generative Adversarial Networks(GAN).The generator in this network is based on theU-Net *** features a newhourglass structure that preserves the characteristics of the deep *** addition,the network incorporates two loss functions to generate natural and high-quality images:Low Frequency(LF)loss and High Frequency(HF)*** loss uses a pretrained VGG-16 network and is configured using a specific layer that best represents *** can enhance the performance in the high-frequency *** contrast,LF loss is used to handle the low-frequency *** two loss functions facilitate the generation of images by the generator,which can mislead the discriminator while accurately generating high-and low-frequency ***,by removing the blocking effects frommaximum lossy compressed images,images inwhich identities could be recognized are *** study represents a significant improvement over previous research in terms of the image resolution performance.

关键词： JPEG lossy compression restoration image generation GAN