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Relationship between triphasic mechanical properties of articular cartilage and osteoarthritic grade

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Science China(Life Sciences) 2012年第5期55卷 444-451页

作者： NIU HaiJun liu chengrui LIAng WANG Qing WANG YueXiang LI DeYu FAN YuBo Key Laboratory of Ministry of Education for Biomechanics and Mechanobiology School of Biological Science and Medical Engineering Beihang University Beijing 100191 China School of Biomedical Engineering Southern Medical University Guangzhou 510515 China Department of Ultrasound People Liberation Army General Hospital Beijing 100853 China

The purpose of this study was to explore the triphasic mechanical properties of osteoarthritic cartilage with different pathological ***,samples of cartilage from rabbits with different stages of osteoarthritis (OA) were *** this,the cartilage was strained by a swelling experiment,and changes were measured using a high-frequency ultrasound *** result,together with fixed charge density and water volume fraction of cartilage samples,was used to estimate the uniaxial modulus of the cartilage tissue,based on a triphasic *** the control cartilage samples,the uniaxial elastic modulus on the cartilage surface was lower than those in the middle and deep *** an increase in the OA grade,the uniaxial elastic modulus of the surface,middle and deep layers decreased.A significant difference was found in the surface elastic modulus of different OA grades (P<0.01),while no significant differences were identified for OA cartilages of Grades 1 and 2 in the middle and deep layers (P<0.01).Compared with Grades 1 and 2,there was a significant reduction in the elastic modulus in the middle and deep layers of Grade 3 OA cartilage (P<0.05).Overall,this study may provide a new quantitative method to evaluate the severity of OA using the mechanical properties of cartilage tissue.

关键词： osteoarthritis grade triphasic theory ultrasound uniaxial modulus

Design of Sensor Placement Based on Fault Diagnosability 36

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Design of Sensor Placement Based on Fault Diagnosability

Study on the Impact of Filter Layer Permeability on Revetment Top Layer Stability under Wave Action

第36届中国控制会议

作者： Xiaoqiang Hu Xiaoli Zhang Xiafu Peng Qi Ding chengrui liu Department of Automation Xiamen University Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control Engineering

ISBN: (纸本)9781538629185

This paper studies the sensor optimization configuration which meets the fault diagnosability of affine nonlinear faulty *** of all,the judgment method of fault diagnosability and the relevant quantitative evaluation indexes based on the differential geometry theory are *** the optimal sensor allocation model is built,and the pagerank algorithm of the web page ranking is introduced into the configuration *** differ from the new intellective heuristic algorithms,the weighted pagerank algorithm shifts the focus from designing an optimal subset search algorithm of better performance out to evaluating the important degree of each measuring point,and makes use of the analytic model more efficiently rather than the direct graph *** the end,a validation example of the point mass satellite system is presented to demonstrate the effectiveness of the proposed approach.

关键词： sensor optimization configuration fault diagnosability pagerank algorithm

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Journal of Shipping and Ocean Engineering 2015年第6期5卷 327-333页

作者： Liehong Ju Junning Pan chengrui liu Nanjing Hydraulic Research Institute Nanjing 210024 China Hehai University Nanjing 210029 China

In the design of revetment engineering under wave action, to resist the wave action, the pattern of top layer-filter layer-core （subsoil） is often adopted. In general, the structure of top layer is usually single discrete blocks, typically accropode blocks, four-leg square hollow blocks and barrier boards, and also acropode, riprap, paved rock blocks or concrete slabs with smaller waves. Such top layer has been provided with many research findings on its stability and is widely used in engineering. Setting a filter layer between the top layer and the lower dike core mainly has two functions：（1） giving certain permeability, to minimize the hydrodynamic load directly acting on the lower foundation soil; （2） giving certain hydraulic tightness, to prevent fine sediment of the lower foundation soil from being washed out. This paper is focused on a special filter layer with geotextile as its upper structure and coarse aggregate as its lower structure. By simulating geotextile with different permeability and coarse aggregate with different size, the pressure of top of cover layer and the down side of the geotextile is tested under wave actions, and compared with theoretical analysis, in this way, how the permeability of geotextile impacts the stability of top layer is studied. The research shows that when the filter layer under the geotextile has high permeability and the geotextile＇s permeability gets poorer, the uplift force to geotextile and the top layer will be increased under wave action, which will cause damage to the top layer when it is greater than the vertical component of the underwater gravity along the slope surface.

关键词： Revetment wave filter layer geotextile permeability uplift force.

Research on fault diagnosis method of control moment gyroscope based on K-means algorithm

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Research on fault diagnosis method of control moment gyrosco...

Discrete-Time Integral Sliding Mode Fault-Tolerant Control with Uncertainties

第三十九届中国控制会议

作者： Wenjing liu Li Yuan Shuyi Wang chengrui liu Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control Engineering

A fault diagnosis method of control moment gyroscope（CMG） based on K-means algorithm is proposed to improve the fault diagnosis accuracy by considering the hidden correlation between multidimensional telemetry data. Principal component analysis（PCA） and t-distribution random neighborhood embedding（t-SNE） are used to extract features of CMG digital and physical data. On this basis, the fault diagnosis process of CMG based on K-means algorithm is supplied. Finally, the effectiveness of the proposed method is verified by using the actual in-orbit CMG data.

关键词： Control moment gyroscope Fault diagnosis PCA t-SNE K-means algorithm

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Discrete-Time Integral Sliding Mode Fault-Tolerant Control w...

2015年中国智能自动化学术会议

作者： Duan Wenjie Wang Dayi liu chengrui Beijing Institute of Control Engineering

This paper researches fault-tolerant control for discrete-time multi-input multi-output(MIMO) linear time-invariant(LTI) systems with both matched and unmatched uncertainties.A discrete-time integral sliding mode(DISM) controller and an improved direct method for control allocation are proposed as the reconfigurable control ***-loop stability with matched and unmatched uncertainties for discrete-time MIMO LTI systems with DISM is studied,and the accuracy boundaries for are determined for the final states.A spacecraft model is simulated with multi-faults,efficiency factor inaccuracies,matched uncertainties,and unmatched uncertainties,which exemplifies our FTC scheme.

关键词： Discrete-time Integral sliding mode Fault-tolerant Uncertainties

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基于方差随机序列的故障诊断方法

机械强度 2006年第2期28卷 190-195页

作者：刘成瑞傅惠民北京航空航天大学小样本技术研究中心北京100083

研究发现,方差随机序列的样本标准差能很好表征设备性能的稳定状况,由此提出一种新的故障诊断方法,该方法首先给出一种新的故障诊断特征量,然后采用Mahalanobis距离建立相应的判别函数,进而能对谱分析、时频分析等传统方法无法诊断而工... 详细信息

研究发现,方差随机序列的样本标准差能很好表征设备性能的稳定状况,由此提出一种新的故障诊断方法,该方法首先给出一种新的故障诊断特征量,然后采用Mahalanobis距离建立相应的判别函数,进而能对谱分析、时频分析等传统方法无法诊断而工程中又大量存在的一类故障模式进行准确分析和判别。

关键词：故障诊断故障模式故障特征量样本标准差 Mahalanobis距离判别函数设备稳定性

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S—N曲线和P—S—N曲线小子样测试方法

机械强度 2006年第4期28卷 552-555页

作者：傅惠民刘成瑞北京航空航天大学小样本技术研究中心北京航空航天大学小样本技术研究中心北京100083

采用异方差回归分析理论,建立一种S—N曲线和P—S—N曲线小子样测试方法,可以对金属材料中寿命区的S—N曲线和P—S—N曲线进行散点测试。该方法能将一条S—N曲线上的所有试验数据作为一个整体进行统计分析,实现多母体联合推断,信息量远... 详细信息

采用异方差回归分析理论,建立一种S—N曲线和P—S—N曲线小子样测试方法,可以对金属材料中寿命区的S—N曲线和P—S—N曲线进行散点测试。该方法能将一条S—N曲线上的所有试验数据作为一个整体进行统计分析,实现多母体联合推断,信息量远远大于成组试验法,既可节省大量试件,又能提高测试精度。此外,该方法对成组试验数据的分析精度也比成组试验法高,可以对过去积累的S—N曲线试验数据进行处理,在不补充试验的情况下,即可得到P—S—N曲线。大量Monte Carlo模拟验证和工程应用表明,在精度相同的情况下,该方法可以比成组试验法节省60%以上的试件。

关键词：小子样测试整体估计应力疲劳应力—寿命曲线寿命估算

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基于分布式专家系统的运载火箭故障诊断技术

北京航空航天大学学报 2007年第8期33卷 930-932,953页

作者：刘成瑞张庆振任章北京航空航天大学自动化科学与电气工程学院北京100083

针对运载火箭结构庞大,各分系统纵横交错、相互耦合的特点,基于分布式专家系统思想,提出了一种分布式运载火箭故障诊断技术方案.该方案采用产生式知识表达技术,将专家知识通过由测点表、征兆表、规则表和结论表组成的4表结构来表示,具... 详细信息

针对运载火箭结构庞大,各分系统纵横交错、相互耦合的特点,基于分布式专家系统思想,提出了一种分布式运载火箭故障诊断技术方案.该方案采用产生式知识表达技术,将专家知识通过由测点表、征兆表、规则表和结论表组成的4表结构来表示,具有表述清晰、易于扩展和移植的特点.推理机制采用分布式推理和分级推理相结合的方式.分布式推理将运载火箭的系统级故障与各分系统级故障分别同时进行诊断,可有效提高诊断速度.分级推理将危害级别高的故障优先进行诊断,因此运载火箭一旦有危害程度大的故障发生时,可以及时发现、及时处置,从而使故障对系统的影响降至最低.

关键词：诊断专家系统运载火箭产生式规则知识表达推理机

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定量与定性相结合的动量轮故障可诊断性评价

中国空间科学技术 2011年第4期31卷 54-63页

作者：刘文静刘成瑞王南华王大轶北京控制工程研究所北京100190 空间智能控制技术重点实验室北京100190

为了提高动量轮的故障诊断性能,采用定量与定性相结合的方法对故障可诊断性评价方法开展研究。在分析动量轮和控制器模型的基础上,建立定量的动量轮闭环系统模型;分析动量轮的各种故障模式,将其分为测量类、驱动类和控制器类故障,并在... 详细信息

为了提高动量轮的故障诊断性能,采用定量与定性相结合的方法对故障可诊断性评价方法开展研究。在分析动量轮和控制器模型的基础上,建立定量的动量轮闭环系统模型;分析动量轮的各种故障模式,将其分为测量类、驱动类和控制器类故障,并在动量轮系统模型中进行表示;依据故障到输出的传递函数是否等于0以及不同故障到输出的传递函数是否相同的思路,研究各类故障的可检测性和可分离性判断条件,对动量轮的各故障模式进行评价,给出相应的评价结果对于不可分离的故障集合,研究基于定性模型的故障可诊断性评价方法,即根据动量轮各功能模块之间的关系,结合动量轮的故障模式影响分析结果,建立故障与征兆之间的关联矩阵,通过分析各故障对应的数据,进一步给出动量轮故障可诊断性的评价结果。最后,提出故障可诊断性相关的定量指标,根据动量轮故障可诊断性评价结果,给出各故障以及动量轮的可检测度和可分离度等,为后续故障可诊断性设计提供依据。

关键词：动量轮故障可诊断性评价故障可检测性故障可分离性卫星