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Real-time reliability prediction for dynamic systems with both deteriorating and unreliable components

Science in china(Series F) 2009年第11期52卷 2234-2246页

作者： xu zhengguo1,2, ji yindong2,3 & zhou donghua1,2?2? 1 department of automation, tsinghua university, beijing 100084, china 2 tsinghua National Laboratory for Information Science and Technology, tsinghua university, beijing 100084, china 3 Research Institute of Information Technology (RIIT), tsinghua university, beijing 100084, china department of automation Tsinghua University Beijing China tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China Research Institute of Information Technology (RIIT) Tsinghua University Beijing China

As an important technology for predictive maintenance, failure prognosis has attracted more and more attentions in recent years. Real-time reliability prediction is one effective solution to failure prognosis. Considering a dynamic system that is composed of normal, deteriorating and unreliable components, this paper proposes an integrated approach to perform real-time reliability prediction for such a class of systems. For a deteriorating component, the degradation is modeled by a time-varying fault process which is a linear or approximately linear function of time. The behavior of an unreliable component is described by a random variable which has two possible values corresponding to the operating and malfunction conditions of this component. The whole proposed approach contains three algorithms. A modified interacting multiple model particle filter is adopted to estimate the dynamic system＇s state variables and the unmeasurable time-varying fault. An exponential smoothing algorithm named the Holt＇s method is used to predict the fault process. In the end, the system＇s reliability is predicted in real time by use of the Monte Carlo strategy. The proposed approach can effectively predict the impending failure of a dynamic system, which is verified by computer simulations based on a three-vessel water tank system.

关键词： reliability failure prognostics dynamic systems fault prediction particle filtering interacting multiple model exponential smoothing,predictive maintenance

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A new DSmT combination rule in open frame of discernment and its application

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Science china(Information Sciences) 2012年第3期55卷 551-557页

作者： WEN ChengLin1, xu XiaoBin1,2 , jiANG HaiNa1 & zhou Zhe1 1School of automation, Hangzhou DianZi university, Hangzhou 310018, china 2department of automation and tsinghua National Laboratory for Information Science and Technology, tsinghua university, beijing 100049, china School of automation Hangzhou DianZi University department of automation and tsinghua National Laboratory for Information Science and Technology Tsinghua University

A new combination rule based on Dezert-Smarandache theory (DSmT) is proposed to deal with the conflict evidence resulting from the non-exhaustivity of the discernment frame. A two-dimensional measure factor in Dempster-Shafer theory (DST) is extended to DSmT to judge the conflict degree between evidence. The original DSmT combination rule or new DSmT combination rule can be selected for fusion according to this degree. Finally, some examples in simultaneous fault diagnosis of motor rotor are given to illustrate the effectiveness of the proposed combination rule.

关键词： DSmT rule of combination open frame of discernment evidence conflict simultaneous faults diagnosis generalized basic probability assignment

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Approximating probability distribution of circuit performance function for parametric yield estimation using transferable belief model

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Science china(Information Sciences) 2013年第11期56卷 106-124页

作者： xu XiaoBin zhou donghua ji yindong WEN ChengLin School of automation and Institute of Systems Science and Control Engineering Hangzhou Dianzi University department of automation and tsinghua National Laboratory for Information Science and Technology Tsinghua University Research Institute of Information Technology (RIIT) Tsinghua University

This paper applies the transferable belief model(TBM)interpretation of the Dempster-Shafer theory of evidence to approximate distribution of circuit performance function for parametric yield *** input parameters of performance function as credal variables defned on a continuous frame of real numbers,the suggested approach constructs a random set-type evidence for these *** corresponding random set of the function output is obtained by extension principle of random *** the TBM framework,the random set of the function output in the credal state can be transformed to a pignistic state where it is represented by the pignistic cumulative *** an approximation to the actual cumulative distribution,it can be used to estimate yield according to circuit response *** advantage of the proposed method over Monte Carlo(MC)methods lies in its ability to implement just once simulation process to obtain an available approximate value of yield which has a deterministic estimation *** the same error,the new method needs less number of calculations than MC methods.A track circuit of high-speed railway and a numerical eight-dimensional quadratic function examples are included to demonstrate the efciency of this technique.

关键词： Dempster-Shafer theory of evidence Monte Carlo methods parametric yield random set transferable belief model

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H∞ Filtering for a Class of Networked Systems with Randomly Occurring Quantizations

H∞ Filtering for a Class of Networked Systems with Randomly...

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第三十届中国控制会议

作者： HE Xiao~1,WANG Zidong~(2,3),ji yindong~1,zhou donghua~2 1.Research Institute of Information Technology,tsinghua university,beijing 100084,P.R.china 2.department of automation,tsinghua university,beijing 100084,P.R.china 3.department of Information Systems and Computing,Brunei university,Uxbridge UB8 3PH,United Kingdom

In this paper,the H filtering problem is investigated for a class of discrete-time networked systems with random- ly occurring quantizations(ROQs).Logarithmic quantizers with different quantization laws are considered and a Bernoulli distributed stochastic sequence is utilized to determine which quantizer is used at a certain time *** converting the quantization effects into sector-bounded parameter uncertainties,a sufficient condition ensuring the existence of the desirable filters is proposed by using the Lyapunov function approach,and the parameters of the desired filters can further be obtained.A numerical example is employed to illustrate the applicability of the proposed technique.

关键词： H∞ Filtering Networked Systems(NSs) Randomly Occurring Quantizations(ROQs)

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Real-world effectiveness of early insulin therapy on the incidence of cardiovascular events in newly diagnosed type 2 diabetes

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Signal Transduction and Targeted Therapy 2024年第7期9卷 2953-2959页

作者： Sihui Luo xueying Zheng Wei Bao Sheng Nie Yu Ding Tong Yue Yilun zhou Ying Hu Hua Li Qiongqiong Yang Qijun Wan Bicheng Liu Hong xu Guisen Li Gang xu Chunbo Chen Huafeng Liu Yongjun Shi Yan Zha Yaozhong Kong Guobin Su Ying Tang Mengchun Gong Linong ji Fan Fan Hou jianping Weng department of Endocrinology First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHeifeiChina Institute of Public Health Sciences Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiChina Division of Nephrology National Clinical Research Center for Kidney DiseaseState Key Laboratory of Organ Failure ResearchNanfang HospitalSouthern Medical UniversityGuangzhouChina department of Nephrology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina The Second Affiliated Hospital of Zhejiang university School of Medicine HangzhouChina Sir Run Run Shaw Hospital Zhejiang University School of MedicineHangzhouChina department of Nephrology Sun Yat-Sen Memorial HospitalSun Yat-Sen UniversityGuangzhouChina The Second People’s Hospital of Shenzhen Shenzhen UniversityShenzhenChina Institute of Nephrology Zhongda HospitalSoutheast University School of MedicineNanjingChina Children’s Hospital of Fudan university ShanghaiChina Renal department and Institute of Nephrology Sichuan Provincial People’s HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaSichuan Clinical Research Center for Kidney DiseasesChengduChina Division of Nephrology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina department of Critical Care Medicine Maoming People’s HospitalMaomingChina Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City Institute of NephrologyAffiliated Hospital of Guangdong Medical UniversityZhanjiangChina Huizhou Central People’s Hospital Sun Yat-Sen UniversityHuizhouChina Guizhou Provincial People’s Hospital Guizhou UniversityGuiyangChina department of Nephrology the First People’s Hospital of FoshanFoshanChina department of Nephrology Guangdong Provincial Hospital of Chinese Medicinethe Second Affiliated Hospitalthe Second Clinical CollegeGuangzhou University of Chinese Medicin

Early insulin therapy is capable to achieve glycemic control and restoreβ-cell function in newly diagnosed type 2 diabetes(T2D),but its effect on cardiovascular outcomes in these patients remains *** this nationwide real-world study,we analyzed electronic health record data from 19 medical centers across china between 1 January 2000,and 26 May *** included 5424 eligible patients(mean age 56 years,2176 women/3248 men)who were diagnosed T2D within six months and did not have prior cardiovascular *** Cox regression models were used to estimate the associations of early insulin therapy(defined as the first-line therapy for at least two weeks in newly diagnosed T2D patients)with the incidence of major cardiovascular events including coronary heart disease(CHD),stroke,and hospitalization for heart failure(HF).During 17,158 persons years of observation,we documented 834 incident CHD cases,719 stroke cases,and 230 hospitalized cases for *** diagnosed T2D patients who received early insulin therapy,compared with those who did not receive such treatment,had 31%lower risk of incident stroke,and 28%lower risk of hospitalization for *** significant difference in the risk of CHD was *** found similar results when repeating the aforesaid analysis in a propensity-score matched population of 4578 patients and with inverse probability of treatment weighting *** findings suggest that early insulin therapy in newly diagnosed T2D may have cardiovascular benefits by reducing the risk of incident stroke and hospitalization for HF.

关键词： cardiovascular treatment nationwide

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Rat adipose-derived stromal cells expressing BMP4 induce ectopic bone formation in vitro and in vivo

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Acta Pharmacologica Sinica 2006年第12期27卷 1608-1615页

作者： Lin LIN~2 Xin FU~2 Xin ZHANG~2 Lian-xu CHEN~2 ji-ying ZHANG~2 Chang-long YU~(2,4)Kang-tao MA~3 Chun-yan zhou~(3,4)2 Institute of Sports Medicine,Peking university Third Hospital,beijing 100083,china 3 department of Biochemistry and Molecular Biology,Peking university School of Basic Medical Science,beijing 100083,china Institute of Sports Medicine Peking University Third Hospital Beijing 100083 China.

Aim:Bone morphogenetic protein 4(BMP4)is one of the main local contributingfactors in callus formation in the early phase of fracture ***-derivedstromal cells(ADSC)are multipotent *** present study was conducted toinvestigate the osteogenic potential of ADSC when exposed to adenovirus con-taining BMP4 cDNA(Ad-BMP4).Methods:ADSC were harvested from Sprague-Dawley *** exposure to Ad-BMP4,ADSC were assessed by alkaline phos-phatase activity(ALP)assay,RT-PCR and yon Kossa ***4 expressionwas assessed by RT-PCR,immunofluorescence and Western blot analysis,ADSCtransduced with Ad-BMP4 were directly injected into the hind limb muscles ofathyrnic *** Ad-EGFP(enhanced green fluorescence protein)served *** animals were examined by X-ray film and histological ***:The expression of BMP4 was confirmed at both mRNA and protein *** expression of the osteoblastic gene,ALP activity and yon Kossa stainingconfirmed that ADSC transduced with Ad-BMP4 underwent rapid and markedosteoblast differentiation,whereas ADSC transduced with Ad-EGFP and cells leftalone displayed no osteogenic differentiation.X-ray and histological examinationconfirmed new bone formation in athymic mice transplanted with ADSC trans-duced with ***:Our data demonstrated successful osteo-genic differentiation of ADSC transduced with Ad-BMP4 in vitro and in *** may be an ideal source of mesenchyme lineage stem cells for gene therapyand tissue engineering.

关键词： adipose-derived stromal cells BMP4 gene therapy bone formation

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铈纳米膜对LY12铝合金表面耐蚀性能的影响

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中国稀土学报 2003年第3期21卷 303-306页

作者：纪红许越周德瑞周育红哈尔滨工业大学应用化学系黑龙江哈尔滨150001 北京航空航天大学材料科学与工程学院北京100083

铝合金表面在使用环境中发生的腐蚀破坏限制了它的应用。采用Sol gel提拉法在LY12铝合金表面制备的铈纳米膜具有无毒、无污染和明显的防腐作用。表面分析测试结果表明,膜的主要成分为铈的氧化物;用XRD测试结果估算出膜中铈的粒径为10nm... 详细信息

铝合金表面在使用环境中发生的腐蚀破坏限制了它的应用。采用Sol gel提拉法在LY12铝合金表面制备的铈纳米膜具有无毒、无污染和明显的防腐作用。表面分析测试结果表明,膜的主要成分为铈的氧化物;用XRD测试结果估算出膜中铈的粒径为10nm。盐水浸渍法试验结果证明了成膜后LY12铝合金表面的腐蚀速率明显降低;成膜后试样的Tafel曲线腐蚀电势正移;EIS分析结果表明铈纳米膜具有明显的电容特征,该膜阻碍了铝合金表面腐蚀反应的发生;初步提出了铈纳米膜改善LY12铝合金腐蚀性能的机制。

关键词：金属材料铝合金纳米膜耐蚀性稀土

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串联质谱图谱从头测序算法研究进展

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生物化学与生物物理进展 2010年第12期37卷 1278-1288页

作者：孙汉昌张纪阳刘辉张伟徐长明马海滨朱云平谢红卫国防科学技术大学机电工程与自动化学院自动控制系长沙410073 军事医学科学院放射与辐射医学研究所北京蛋白质组研究中心蛋白质组学国家重点实验室北京102206

近年来,基于质谱技术的高通量蛋白质组学研究发展迅速,利用串联质谱图谱鉴定蛋白质是其数据处理中一个基础而又重要的环节.由于不需要利用蛋白质序列数据库,从头测序方法能够分析新物种或者基因组未测序物种的串联质谱数据,具有数据库... 详细信息

近年来,基于质谱技术的高通量蛋白质组学研究发展迅速,利用串联质谱图谱鉴定蛋白质是其数据处理中一个基础而又重要的环节.由于不需要利用蛋白质序列数据库,从头测序方法能够分析新物种或者基因组未测序物种的串联质谱数据,具有数据库搜索方法不可替代的优势.简要介绍高通量串联质谱图谱从头测序问题及其研究现状.归纳出几种典型的计算策略并分析了各种策略的优缺点.总结常用的从头测序算法和软件,介绍算法评估的各种指标和常用评估数据集,概括各种算法的特点,展望未来研究可能的发展方向.

关键词：肽段串联质谱从头测序算法研究计算蛋白质组学

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蛋白质质谱分析的无标记定量算法研究进展

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生物化学与生物物理进展 2011年第6期38卷 506-518页

作者：张伟张纪阳刘辉孙汉昌徐长明马海滨朱云平谢红卫国防科学技术大学机电工程与自动化学院自动控制系长沙410073 军事医学科学院放射与辐射医学研究所北京蛋白质组研究中心蛋白质组学国家重点实验室北京102206

作为发现疾病相关生物标志物的重要途径,定量研究已成为蛋白质组学的热点问题.随着实验方法的发展和改进,定量数据处理算法也在不断更新和完善.将现有的无标记定量方法归纳为需要/不需要鉴定结果两类方法,分析比较了两类方法的异同及优... 详细信息

作为发现疾病相关生物标志物的重要途径,定量研究已成为蛋白质组学的热点问题.随着实验方法的发展和改进,定量数据处理算法也在不断更新和完善.将现有的无标记定量方法归纳为需要/不需要鉴定结果两类方法,分析比较了两类方法的异同及优缺点,详细讨论了所涉及的主要算法,总结了一些常用的无标记定量软件及对应的网络资源.展望了无标记定量数据分析的未来研究方向.

关键词：定量蛋白质组质谱无标记定量定量算法统计学分析

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基于Sentinel-5P卫星反演京津冀地区近地面NO_(2)浓度研究

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环境科学研究 2024年第6期37卷 1223-1231页

作者：周刚徐彬仁徐炜达程文晨尹文君王凌清华大学自动化系北京100084 北京英视睿达科技股份有限公司北京100070

为充分利用卫星传感器在探索长时间、大范围区域内近地面二氧化氮(NO2)浓度时空变化规律方面的优势,进一步提高卫星近地面NO_(2)浓度预测的准确性,本研究以Sentinel-5P卫星TROPOMI传感器观测的对流层NO_(2)柱浓度为基础,提出一种融合多... 详细信息

为充分利用卫星传感器在探索长时间、大范围区域内近地面二氧化氮(NO2)浓度时空变化规律方面的优势,进一步提高卫星近地面NO_(2)浓度预测的准确性,本研究以Sentinel-5P卫星TROPOMI传感器观测的对流层NO_(2)柱浓度为基础,提出一种融合多源地理要素的“自上而下”近地面NO_(2)浓度遥感估算方法,综合分析随机森林模型(RF)、极致梯度提升树模型(XGBoost)和轻型梯度提升树模型(LightGBM)的性能,基于3种树模型对2019−2020年京津冀地区近地面NO_(2)浓度进行反演,并采用十折交叉验证方法分别对3种模型在近地面NO_(2)浓度预测中的精度差异与稳定性进行了检验比较,利用拟合优度(R2)、均方根误差(RMSE)和平均绝对误差(MAE)对模型进行精度评价,最终选取XGBoost以实现京津冀地区卫星近地面NO_(2)浓度的高效分析预测(R2=0.85,RMSE=6.61μg/m^(3),MAE=2.09μg/m^(3)),在此基础上,从季度、年份等时间尺度对近地面NO_(2)浓度进行空间分析。结果表明:①由于2020年新型冠状病毒感染疫情反弹带来的人类生产活动和出行活动的大量减少,2019年近地面NO_(2)浓度(13.96μg/m^(3))比2020年(13.04μg/m^(3))整体偏高。②近地面NO_(2)浓度具有明显的季节性变化特征,春、夏两季由于大气扩散条件较好,近地面NO_(2)浓度相对较低,在冬季达到全年峰值。③基于SHAP值(沙普利加性解释法)方法对模型特征进行空间分析,并定量研究每个特征对模型的正负贡献程度,其中,对流层NO_(2)柱浓度对预测近地面NO_(2)浓度起到主要促进作用,大气边界层高度对预测近地面NO_(2)浓度起到抑制作用,另外太阳直射辐射、人口密度、地表温度及降水量等指标均对预测近地面NO_(2)浓度有明显影响。研究显示,XGBoost能够更加稳定和准确地预测卫星近地面NO_(2)浓度,为准确识别近地面NO_(2)浓度时空分布特征提供新的手段,可在一定程度上突破现阶段NO_(2)地面监测稀疏的空间局限以及卫星对流层NO_(2)柱浓度代表性不足的缺陷。

关键词： NO_(2) TROPOMI 机器学习 XGBoost SHAP值

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