The COVID-19(Coronavirus Disease 19)pandemic has demonstrated that cities are at the center of major contemporary events.The epidemiological crisis has highlighted the importance of the urban environment,challenging p...The COVID-19(Coronavirus Disease 19)pandemic has demonstrated that cities are at the center of major contemporary events.The epidemiological crisis has highlighted the importance of the urban environment,challenging public managers on managing cities.An initiative that aims to assist in this management process is the concept of Smart Cities,which uses ICT(Information and Communication Technology)as tools for transforming urban dynamics,and through urban indicators,measures information about cities.Thus,the research aimed to analyze the health indicators of Passo Fundo/RS,seeking to analyze the interrelationship of these indicators with the epidemiological data from COVID-19.In the methodology,multi-method procedures were applied,using the indicators of the Connected Smart Cities Ranking as reference,as well as a regional selection of medium-sized cities in the southern region of Brazil.The results show that the health indices of Passo Fundo are,for the most part,lower than those of the analyzed cities,with the indicator related to Population Coverage of the Family Health team as the main weakness.However,it also presents satisfactory indices as is the case of the indicator of Beds/1,000 inhabitants.Regarding the epidemiological picture of COVID-19,Passo Fundo had a high lethality rate when compared to the other analyzed cities.展开更多
This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,...This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe in the groundwater samples.Moreover,geographic information system(GIS),XLSTAT,and IBM SPSS Statistics 20 software were used for spatial distribution modeling,principal component analysis(PCA),cluster analysis(CA),and Quantile-Quantile(Q-Q)plotting to determine groundwater pollution sources,similarity index,and normal distribution reference line for the selected parameters.The mean values of pH,TDS,elevation,ORP,temperature,depth,and Br were 7.2,322 mg/L,364 m,188 mV,29.6℃,70 m,0.20 mg/L,and PHMs like Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe were 0.38,0.26,0.08,0.27,0.36,0.22,0.04,0.43 and 0.86 mg/L,respectively.PHMs including Cr(89%),Cd(43%),Mn(23%),Pb(79%),Co(20%),and Fe(91%)exceeded the guideline values set by the world health organization(WHO).The significant R^(2)values of PCA for selected parameters were also determined(0.62,0.67,0.78,0.73,0.60,0.87,-0.50,0.69,0.70,0.74,-0.50,0.70,0.67,0.79,0.59,and-0.55,respectively).PCA revealed three geochemical processes such as geogenic,anthropogenic,and reducing conditions.The mineral phases of Cd(OH)_(2),Fe(OH)_(3),FeOOH,Mn_(3)O_(4),Fe_(2)O_(3),MnOOH,Pb(OH)_(2),Mn(OH)_(2),MnO_(2),and Zn(OH)_(2)(-3.7,3.75,9.7,-5.8,8.9,-3.6,2.2,-4.6,-7.7,-0.9,and 0.003,respectively)showed super-saturation and under-saturation conditions.Health risk assessment(HRA)values for PHMs were also calculated and the values of hazard quotient(HQ),and hazard indices(HI)for the entire study area were increased in the following order:Cd>Ni>Cu>Pb>Mn>Zn>Cr.Relatively higher HQ and HI values of Ni,Cd,Pb,and Cu were greater than one showing unsuitability of groundwater for domestic,agriculture,and drinking purposes.The long-term ingestion of groundwater could also cause severe health concerns such as kidney,brain dysfunction,liver,stomach problems,and even cancer.展开更多
Rolling element bearings are machine components used to allow circular movement and hence deliver forces between components of machines used in diverse areas of industry.The likelihood of failure has the propensity of...Rolling element bearings are machine components used to allow circular movement and hence deliver forces between components of machines used in diverse areas of industry.The likelihood of failure has the propensity of increasing under prolonged operation and varying working conditions.Hence, the accurate fault severity categorization of bearings is vital in diagnosing faults that arise in rotating machinery.The variability and complexity of the recorded vibration signals pose a great hurdle to distinguishing unique characteristic fault features.In this paper, the efficacy and the leverage of a pre-trained convolutional neural network(CNN) is harnessed in the implementation of a robust fault classification model.In the absence of sufficient data, this method has a high-performance rate.Initially, a modified VGG16 architecture is used to extract discriminating features from new samples and serves as input to a classifier.The raw vibration data are strategically segmented and transformed into two representations which are trained separately and jointly.The proposed approach is carried out on bearing vibration data and shows high-performance results.In addition to successfully implementing a robust fault classification model, a prognostic framework is developed by constructing a health indicator(HI) under varying operating conditions for a given fault condition.展开更多
Aiming at the difficulty of mining fault prognosis starting points and constructing prognostic models for remaining useful life(RUL)prediction of rolling bearings,a RUL prediction method is proposed based on health in...Aiming at the difficulty of mining fault prognosis starting points and constructing prognostic models for remaining useful life(RUL)prediction of rolling bearings,a RUL prediction method is proposed based on health indicator(HI)extraction and trajectory-enhanced particle filter(TE-PF).By extracting a HI that can accurately track the trending of bearing degradation and combining it with the early fault enhancement technology,early abnormal sample nodes can be mined to provide more samples with fault information for the construction and training of subsequent prediction models.Aiming at the problem that traditional degradation rate models based on PF are vulnerable to HI mutations,a TE-PF prediction method is proposed based on comprehensive utilization of historical degradation information to timely modify prediction model parameters.Results from a rolling bearing prognostic study show that prediction starting points can be accurately detected and a reasonable prediction model can be conveniently constructed by the RUL prediction method based on HI amplitude abnormal detection and TE-PF.Furthermore,aiming at the RUL prediction problem under the condition of HI mutation,RUL prediction with probability and statistics characteristics under a confidence interval can be obtained based on the method proposed.展开更多
Efficient and accurate health state estimation is crucial for lithium-ion battery(LIB)performance monitoring and economic evaluation.Effectively estimating the health state of LIBs online is the key but is also the mo...Efficient and accurate health state estimation is crucial for lithium-ion battery(LIB)performance monitoring and economic evaluation.Effectively estimating the health state of LIBs online is the key but is also the most difficult task for energy storage systems.With high adaptability and applicability advantages,battery health state estimation based on data-driven techniques has attracted extensive attention from researchers around the world.Artificial neural network(ANN)-based methods are often used for state estimations of LIBs.As one of the ANN methods,the Elman neural network(ENN)model has been improved to estimate the battery state more efficiently and accurately.In this paper,an improved ENN estimation method based on electrochemical impedance spectroscopy(EIS)and cuckoo search(CS)is established as the EIS-CS-ENN model to estimate the health state of LIBs.Also,the paper conducts a critical review of various ANN models against the EIS-CS-ENN model.This demonstrates that the EIS-CS-ENN model outperforms other models.The review also proves that,under the same conditions,selecting appropriate health indicators(HIs)according to the mathematical modeling ability and state requirements are the keys in estimating the health state efficiently.In the calculation process,several evaluation indicators are adopted to analyze and compare the modeling accuracy with other existing methods.Through the analysis of the evaluation results and the selection of HIs,conclusions and suggestions are put forward.Also,the robustness of the EIS-CS-ENN model for the health state estimation of LIBs is verified.展开更多
Health indicator(HI)construction is a crucial task in degradation evaluation and facilitates the prognostic and health management(PHM)of rotating machinery.Excluding interference from artificial labeling,the HI constr...Health indicator(HI)construction is a crucial task in degradation evaluation and facilitates the prognostic and health management(PHM)of rotating machinery.Excluding interference from artificial labeling,the HI construction approaches in an unsupervised manner have attracted substantial attention.Nevertheless,current unsupervised methods generally struggle with two problems:(1)ignorance of both redundancy between features and global variability of features during the feature selection process;(2)inadequate utilization of information from different sampling moments.To tackle these problems,this work develops a novel unsupervised approach for HI construction that integrates multi-criterion feature selection and the Attentive Variational Autoencoder(Attentive VAE).Explicitly,a multi-criterion feature selection(Mc FS)algorithm together with an elaborately designed metric is proposed to determine a superior feature subset,considering the relevance,the redundancy,and the global variability of features simultaneously.Then,for the adequate utilization of the information from distinct sampling moments,a deep learning model named Attentive VAE is established.The Attentive VAE is solely fed with the selected features in the health state for model training and the HI is derived through the reconstruction error to reveal the degradation degree of machinery.Two case studies based on genuine experimental datasets are involved to quantitatively evaluate the superiority of the developed approach,demonstrating its superiority over other unsupervised methods for characterizing degradation processes.The effectiveness of both the Mc FS algorithm and the Attentive VAE is verified by ablation experiments,respectively.展开更多
The Sendai Framework for Disaster Risk Reduction 2015–2030 recognizes the strong connection between health and disasters and promotes the concept of health resilience throughout.Several of the seven global targets st...The Sendai Framework for Disaster Risk Reduction 2015–2030 recognizes the strong connection between health and disasters and promotes the concept of health resilience throughout.Several of the seven global targets stated in the Sendai Framework are directly related to health in terms of reducing disaster mortality,the number of affected people,disaster damage to critical infrastructure,and disruption of basic services such as health facilities.The Sendai Framework also maintains close coordination with other United Nations landmark agreements relevant to health such as the Sustainable Development Goals.However,the measurement of healthrelated indicators is challenging.Issues arise,for example,in linking deaths to disasters because of the complex interplay between exposure,risk,vulnerability,and hazards.The lack of a universal classification of disasters also means that recording of health data in disasters is not standardized.Developing the guidelines to enable data onthe indicators to be collected and reported to support the Sendai targets requires detailed thinking,time,and consultation with a diverse range of stakeholders.Strong collaboration and partnership will be vital to achieving success.展开更多
OBJeCTIve:To systematically evaluate the long-term effect and safety ofXingnao Kaiqiao nee-dling method in ischemic stroke treatment. DATA ReTRIevAL: We retrieved relevant random and semi-random controlled trials th...OBJeCTIve:To systematically evaluate the long-term effect and safety ofXingnao Kaiqiao nee-dling method in ischemic stroke treatment. DATA ReTRIevAL: We retrieved relevant random and semi-random controlled trials that used theXingnao Kaiqiao needling method to treat ischemic stroke compared with various control treatments such as conventional drugs or other acupuncture therapies. Searched databases included China National Knowledge Infrastructure, Weipu Information Resources System, Wanfang Medical Data System, Chinese Biomedical Literature Database, Cochrane Library, and PubMed, from May 2006 to July 2014. SeLeCTION CRITeRIA: Two authors independently conducted literature screening, quality evaluation, and data extraction. The quality of articles was evaluated according to the Cochrane Reviewers’ Handbook 5.1, and the study was carried out using Cochrane system assessment methods. RevMan 5.2 was used for meta-analysis of the included studies. MAIN OUTCOMe MeASUReS: Mortality rate, recurrence rate, and disability rate were observed. ReSULTS:Nine randomized and semi-randomized controlled trials treating 931 cases of ischemic stroke were included in this review. Meta-analysis results showed that there were no sig-niifcant differences in mortality reduction (risk ratio (RR) = 0.58, 95% conifdence interval (CI): 0.17–1.93,Z = 0.89,P = 0.37) or recurrence rate (RR = 0.55, 95%CI: 0.18–1.70,Z = 1.04,P = 0.30) of ischemic stroke patients between theXingnao Kaiqiao needling and control treatment groups. However, theXingnao Kaiqiao needling method had a tendency towards higher efifcacy in mor-tality reduction and recurrence rates. TheXingnao Kaiqiao needling method was signiifcantly better than that of the control treatment in reducing disability rate (RR = 0.51, 95%CI: 0.27–0.98, Z = 2.03,P 〈 0.05). CONCLUSION:TheXingnao Kaiqiao needling method has a better effect than control treatment in reducing disability rate. The long-term effect ofXingnao Kaiqiao needling against ischemic stroke is better than that of control treatment. However, the limitations of this study limit the strength of the conclusions. Randomized controlled trials with a strict, reasonable design, and multi-center, large-scale samples and follow-up are necessary to draw conclusions aboutXingnao Kaiqiao needling.展开更多
The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral ...The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition.The estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very poor.Totally,12 genera were recorded,of which Porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(p<0.05).The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble.The reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.展开更多
The Yellow River Delta(YRD)has China's largest artificial Robinia pseudoacacia forest,which was planted in the late 1970s and suffered extensive dieback in the 1990s.The health grade of the R.pseudoacacia forest(n...The Yellow River Delta(YRD)has China's largest artificial Robinia pseudoacacia forest,which was planted in the late 1970s and suffered extensive dieback in the 1990s.The health grade of the R.pseudoacacia forest(named canopy vigor grade,CVG)could be achieved by using high-resolution images and canopy vigor indicators(CVIs).However,a previous study showed that there was no significant correlation between CVG and the field-estimated aboveground biomass(AGB)of R.pseudoacacia forest.Therefore,this study aims to construct forest health indicators(FHIs)based on canopy spatial structure parameters extracted from LiDAR.The FHIs included Weibull_α(the scale parameter of the Weibull density function that reflects the shape of the tree canopy),VCI(vertical complexity index),sdCC(the standard deviation of canopy cover),H99(the 99th percentile height)and cvLAD(the coefficient of variation of leaf area density),and could significantly distinguish three forest health grades(FHG)(p<0.05).The FHG was positively correlated with forest AGB(rs=0.51,p=0.004),and the similarity value with CVG was 63.33%.The results of this study confirmed that the FHIs can reflect both canopy vigor and tree productivity,and distinguish forest health status without prior classification information.展开更多
This paper analyzes the impact of health indicators on an individual's trip and mode choices to out-patient care facilities.The study's focus is an out-patient trip to a health care facility,and the source of ...This paper analyzes the impact of health indicators on an individual's trip and mode choices to out-patient care facilities.The study's focus is an out-patient trip to a health care facility,and the source of data is the China Health and Retirement Longitudinal Study(CHARLS)for 2011.2013 and 2015.Based on a random utility framework,the study finds that making a rip to ureat an ilness or for a check-up increases the likelihood of an out-patient trip by 52 and 31 probability points,respectively.Out-patient visits for which in-surance is not relevant,When the individual pays most of the out:of-pocket costs and when the facility is a public facility are also important factors.Diagnosed and other per-sonal health factors have some but much more modest effects on one's trip choice.The analysis also identifies differential modal impacts of health indicators.A series of robustness tests generally confirm the results and identify areas for further research.Including a no-trip option,the biannual sunvey and infrequent out-patient trip-making mitigate endogeneity concerns.The analysis has broad health policy and transportation implications for an ageing population whose share is increasing.展开更多
Objective:The purpose of this study was to understand the health-related behaviors in children of ethnic minorities and Han nationality so as to provide a basis for formulating a health promotion plan,reasonably alloc...Objective:The purpose of this study was to understand the health-related behaviors in children of ethnic minorities and Han nationality so as to provide a basis for formulating a health promotion plan,reasonably allocating health resources,and improving health conditions of the entire population of children.Methods:The selection and processing of study subjects,as well as health-related behaviors,were based on the 2009 Chinese Health and Nutrition Survey(CHNS)data.A total of 867 children were involved in this study,including 762 Han children and 105 minority children.Comparative analysis was conducted on the reported ratio of health-related behaviors,including society and family variation,as well as dietary habit variation,and health condition scores.Results:A comparison on health-related behaviors between ethnic minority and Han children indicated the following:with respect to society and family variation,statistical significance(P<0.05)existed between the two groups in health-related behaviors influenced by parents who did or did not stay at home,level of education,and medical insurance status;and with respect to dietary habit variation,statistical significance(P<0.05)existed in the differences of dietary habits between the two groups.Moreover,differences in the weight-forage Z score(WAZ),weight-forheight Z score(WHZ),and body mass index-for-age Z score(BAZ)between the two groups were statistically significant(P<0.05).Conclusion:Health-related behavioral norms and health conditions of ethnic minority children should be further improved.Increased health awareness of families with children and health care system development should be stressed to elevate the health level of the entire population of children in China.展开更多
Background:In Brazil,the Ministry of Health(MH)monitors leprosy using 15 indicators,with the aim of imple-menting and evaluating evidence-based public policies.However,an excessive number of variables can compli-cate ...Background:In Brazil,the Ministry of Health(MH)monitors leprosy using 15 indicators,with the aim of imple-menting and evaluating evidence-based public policies.However,an excessive number of variables can compli-cate the definition of objectives and verification of epidemiological goals.Methods:In this paper,we develop the Global Leprosy Assessment Index(GLAI),a composite measure that integrates two key dimensions for the control the disease:epidemiological and operational.Using a confirmatory factor analysis model to examine 2020 state-level data,we have standardized GLAI to a range of 0 to 1.Results:Higher values within this range indicate a greater severity of the disease.The mean value of the GLAI was 0.67,with a standard deviation of 0.22.Roraima has the highest value,followed by Paraíba with 0.88 while Tocantins records the lowest value of the indicator,followed by Mato Grosso with 0.14.The epidemiological and operational indicators have a positive but statistically insignificant correlation(r=0.25;p-value=0.20).Conclusions:The development of evidence-based public policies depends on the availability of valid and reliable indicators.The GLAI presented in this paper is easily reproducible and can be used to monitor the disease with disaggregated information.Furthermore,the GLAI has the potential to serve as a more robust parameter for evaluating the impact of actions designed to eradicate leprosy in Brazil.展开更多
The study investigates the potential of UAV-based remote sensing technique for monitoring of Norway spruce health condition in the affected forest areas.The objectives are:(1)to test the applicability of UAV visible a...The study investigates the potential of UAV-based remote sensing technique for monitoring of Norway spruce health condition in the affected forest areas.The objectives are:(1)to test the applicability of UAV visible an near-infrared(VNIR)and geometrical data based on Z values of point dense cloud(PDC)raster to separate forest species and dead trees in the study area;(2)to explore the relationship between UAV VNIR data and individual spruce health indicators from field sampling;and(3)to explore the possibility of the qualitative classification of spruce health indicators.Analysis based on NDVI and PDC raster was successfully applied for separation of spruce and silver fir,and for identification of dead tree category.Separation between common beech and fir was distinguished by the object-oriented image analysis.NDVI was able to identify the presence of key indicators of spruce health,such as mechanical damage on stems and stem resin exudation linked to honey fungus infestation,while stem damage by peeling was identified at the significance margin.The results contributed to improving separation of coniferous(spruce and fir)tree species based on VNIR and PDC raster UAV data,and newly demonstrated the potential of NDVI for qualitative classification of spruce trees.The proposed methodology can be applicable for monitoring of spruce health condition in the local forest sites.展开更多
In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on p...In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators (Cls) are presented, and the optimal Cls set is selected by comparing their test statistics according to Mann-Kendall test. Afterwards, the selected CIs are used to generate a health indicator (HI) through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitor- ing of helicopter transmission systems, and it is effective to reduce the test cost and improve the system's reliability.展开更多
文摘The COVID-19(Coronavirus Disease 19)pandemic has demonstrated that cities are at the center of major contemporary events.The epidemiological crisis has highlighted the importance of the urban environment,challenging public managers on managing cities.An initiative that aims to assist in this management process is the concept of Smart Cities,which uses ICT(Information and Communication Technology)as tools for transforming urban dynamics,and through urban indicators,measures information about cities.Thus,the research aimed to analyze the health indicators of Passo Fundo/RS,seeking to analyze the interrelationship of these indicators with the epidemiological data from COVID-19.In the methodology,multi-method procedures were applied,using the indicators of the Connected Smart Cities Ranking as reference,as well as a regional selection of medium-sized cities in the southern region of Brazil.The results show that the health indices of Passo Fundo are,for the most part,lower than those of the analyzed cities,with the indicator related to Population Coverage of the Family Health team as the main weakness.However,it also presents satisfactory indices as is the case of the indicator of Beds/1,000 inhabitants.Regarding the epidemiological picture of COVID-19,Passo Fundo had a high lethality rate when compared to the other analyzed cities.
基金financially supported National Natural Science Foundation of China(Grant Nos.41521001 and 41877204)the 111 Program(State Administration Foreign Experts Affairs&the Ministry of Education of China,Grant No.B18049)the China Postdoctoral Science Foundation(Grant No.2018M642944)。
文摘This study investigates the values of pH,total dissolved solids(TDS),elevation,oxidative reduction potential(ORP),temperature,and depth,while the concentrations of Br,and potentially harmful metals(PHMs)such as Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe in the groundwater samples.Moreover,geographic information system(GIS),XLSTAT,and IBM SPSS Statistics 20 software were used for spatial distribution modeling,principal component analysis(PCA),cluster analysis(CA),and Quantile-Quantile(Q-Q)plotting to determine groundwater pollution sources,similarity index,and normal distribution reference line for the selected parameters.The mean values of pH,TDS,elevation,ORP,temperature,depth,and Br were 7.2,322 mg/L,364 m,188 mV,29.6℃,70 m,0.20 mg/L,and PHMs like Cr,Ni,Cd,Mn,Cu,Pb,Co,Zn,and Fe were 0.38,0.26,0.08,0.27,0.36,0.22,0.04,0.43 and 0.86 mg/L,respectively.PHMs including Cr(89%),Cd(43%),Mn(23%),Pb(79%),Co(20%),and Fe(91%)exceeded the guideline values set by the world health organization(WHO).The significant R^(2)values of PCA for selected parameters were also determined(0.62,0.67,0.78,0.73,0.60,0.87,-0.50,0.69,0.70,0.74,-0.50,0.70,0.67,0.79,0.59,and-0.55,respectively).PCA revealed three geochemical processes such as geogenic,anthropogenic,and reducing conditions.The mineral phases of Cd(OH)_(2),Fe(OH)_(3),FeOOH,Mn_(3)O_(4),Fe_(2)O_(3),MnOOH,Pb(OH)_(2),Mn(OH)_(2),MnO_(2),and Zn(OH)_(2)(-3.7,3.75,9.7,-5.8,8.9,-3.6,2.2,-4.6,-7.7,-0.9,and 0.003,respectively)showed super-saturation and under-saturation conditions.Health risk assessment(HRA)values for PHMs were also calculated and the values of hazard quotient(HQ),and hazard indices(HI)for the entire study area were increased in the following order:Cd>Ni>Cu>Pb>Mn>Zn>Cr.Relatively higher HQ and HI values of Ni,Cd,Pb,and Cu were greater than one showing unsuitability of groundwater for domestic,agriculture,and drinking purposes.The long-term ingestion of groundwater could also cause severe health concerns such as kidney,brain dysfunction,liver,stomach problems,and even cancer.
基金supported by the National Natural Science Foundation of China (42027805)National Aeronautical Fund (ASFC-2017 2080005)National Key R&D Program of China (2017YFC03 07100)。
文摘Rolling element bearings are machine components used to allow circular movement and hence deliver forces between components of machines used in diverse areas of industry.The likelihood of failure has the propensity of increasing under prolonged operation and varying working conditions.Hence, the accurate fault severity categorization of bearings is vital in diagnosing faults that arise in rotating machinery.The variability and complexity of the recorded vibration signals pose a great hurdle to distinguishing unique characteristic fault features.In this paper, the efficacy and the leverage of a pre-trained convolutional neural network(CNN) is harnessed in the implementation of a robust fault classification model.In the absence of sufficient data, this method has a high-performance rate.Initially, a modified VGG16 architecture is used to extract discriminating features from new samples and serves as input to a classifier.The raw vibration data are strategically segmented and transformed into two representations which are trained separately and jointly.The proposed approach is carried out on bearing vibration data and shows high-performance results.In addition to successfully implementing a robust fault classification model, a prognostic framework is developed by constructing a health indicator(HI) under varying operating conditions for a given fault condition.
基金supported by the National Key Research and Development Program of China (No.2018YFB1702401)National Natural Science Foundation of China (Grant No.51975576,51475463).
文摘Aiming at the difficulty of mining fault prognosis starting points and constructing prognostic models for remaining useful life(RUL)prediction of rolling bearings,a RUL prediction method is proposed based on health indicator(HI)extraction and trajectory-enhanced particle filter(TE-PF).By extracting a HI that can accurately track the trending of bearing degradation and combining it with the early fault enhancement technology,early abnormal sample nodes can be mined to provide more samples with fault information for the construction and training of subsequent prediction models.Aiming at the problem that traditional degradation rate models based on PF are vulnerable to HI mutations,a TE-PF prediction method is proposed based on comprehensive utilization of historical degradation information to timely modify prediction model parameters.Results from a rolling bearing prognostic study show that prediction starting points can be accurately detected and a reasonable prediction model can be conveniently constructed by the RUL prediction method based on HI amplitude abnormal detection and TE-PF.Furthermore,aiming at the RUL prediction problem under the condition of HI mutation,RUL prediction with probability and statistics characteristics under a confidence interval can be obtained based on the method proposed.
基金supported by the National Natural Science Foundation of China(No.62173281 and No.61801407)the Sichuan Science and Technology Pro-gram(No.2019YFG0427 and No.2023YFG0108)+1 种基金the China Scholarship Council(No.201908515099)the Fund of Robot Technology used for the Special Environment Key Laboratory of Sichuan Province(No.18kftk03).
文摘Efficient and accurate health state estimation is crucial for lithium-ion battery(LIB)performance monitoring and economic evaluation.Effectively estimating the health state of LIBs online is the key but is also the most difficult task for energy storage systems.With high adaptability and applicability advantages,battery health state estimation based on data-driven techniques has attracted extensive attention from researchers around the world.Artificial neural network(ANN)-based methods are often used for state estimations of LIBs.As one of the ANN methods,the Elman neural network(ENN)model has been improved to estimate the battery state more efficiently and accurately.In this paper,an improved ENN estimation method based on electrochemical impedance spectroscopy(EIS)and cuckoo search(CS)is established as the EIS-CS-ENN model to estimate the health state of LIBs.Also,the paper conducts a critical review of various ANN models against the EIS-CS-ENN model.This demonstrates that the EIS-CS-ENN model outperforms other models.The review also proves that,under the same conditions,selecting appropriate health indicators(HIs)according to the mathematical modeling ability and state requirements are the keys in estimating the health state efficiently.In the calculation process,several evaluation indicators are adopted to analyze and compare the modeling accuracy with other existing methods.Through the analysis of the evaluation results and the selection of HIs,conclusions and suggestions are put forward.Also,the robustness of the EIS-CS-ENN model for the health state estimation of LIBs is verified.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3400700)the China Academy of Railway Sciences Corporation Limited within the major issues of the fund(Grant No.2021YJ212)+1 种基金the National Natural Science Foundation of China(Grant Nos.12072188,12121002)the Natural Science Foundation of Shanghai(Grant No.20ZR1425200)。
文摘Health indicator(HI)construction is a crucial task in degradation evaluation and facilitates the prognostic and health management(PHM)of rotating machinery.Excluding interference from artificial labeling,the HI construction approaches in an unsupervised manner have attracted substantial attention.Nevertheless,current unsupervised methods generally struggle with two problems:(1)ignorance of both redundancy between features and global variability of features during the feature selection process;(2)inadequate utilization of information from different sampling moments.To tackle these problems,this work develops a novel unsupervised approach for HI construction that integrates multi-criterion feature selection and the Attentive Variational Autoencoder(Attentive VAE).Explicitly,a multi-criterion feature selection(Mc FS)algorithm together with an elaborately designed metric is proposed to determine a superior feature subset,considering the relevance,the redundancy,and the global variability of features simultaneously.Then,for the adequate utilization of the information from distinct sampling moments,a deep learning model named Attentive VAE is established.The Attentive VAE is solely fed with the selected features in the health state for model training and the HI is derived through the reconstruction error to reveal the degradation degree of machinery.Two case studies based on genuine experimental datasets are involved to quantitatively evaluate the superiority of the developed approach,demonstrating its superiority over other unsupervised methods for characterizing degradation processes.The effectiveness of both the Mc FS algorithm and the Attentive VAE is verified by ablation experiments,respectively.
文摘The Sendai Framework for Disaster Risk Reduction 2015–2030 recognizes the strong connection between health and disasters and promotes the concept of health resilience throughout.Several of the seven global targets stated in the Sendai Framework are directly related to health in terms of reducing disaster mortality,the number of affected people,disaster damage to critical infrastructure,and disruption of basic services such as health facilities.The Sendai Framework also maintains close coordination with other United Nations landmark agreements relevant to health such as the Sustainable Development Goals.However,the measurement of healthrelated indicators is challenging.Issues arise,for example,in linking deaths to disasters because of the complex interplay between exposure,risk,vulnerability,and hazards.The lack of a universal classification of disasters also means that recording of health data in disasters is not standardized.Developing the guidelines to enable data onthe indicators to be collected and reported to support the Sendai targets requires detailed thinking,time,and consultation with a diverse range of stakeholders.Strong collaboration and partnership will be vital to achieving success.
基金financially supported by grants from Hebei Province Engineering Talent Cultivation Project and Hebei Province Science and Technology Research and Development Projects,No.11276103D-35
文摘OBJeCTIve:To systematically evaluate the long-term effect and safety ofXingnao Kaiqiao nee-dling method in ischemic stroke treatment. DATA ReTRIevAL: We retrieved relevant random and semi-random controlled trials that used theXingnao Kaiqiao needling method to treat ischemic stroke compared with various control treatments such as conventional drugs or other acupuncture therapies. Searched databases included China National Knowledge Infrastructure, Weipu Information Resources System, Wanfang Medical Data System, Chinese Biomedical Literature Database, Cochrane Library, and PubMed, from May 2006 to July 2014. SeLeCTION CRITeRIA: Two authors independently conducted literature screening, quality evaluation, and data extraction. The quality of articles was evaluated according to the Cochrane Reviewers’ Handbook 5.1, and the study was carried out using Cochrane system assessment methods. RevMan 5.2 was used for meta-analysis of the included studies. MAIN OUTCOMe MeASUReS: Mortality rate, recurrence rate, and disability rate were observed. ReSULTS:Nine randomized and semi-randomized controlled trials treating 931 cases of ischemic stroke were included in this review. Meta-analysis results showed that there were no sig-niifcant differences in mortality reduction (risk ratio (RR) = 0.58, 95% conifdence interval (CI): 0.17–1.93,Z = 0.89,P = 0.37) or recurrence rate (RR = 0.55, 95%CI: 0.18–1.70,Z = 1.04,P = 0.30) of ischemic stroke patients between theXingnao Kaiqiao needling and control treatment groups. However, theXingnao Kaiqiao needling method had a tendency towards higher efifcacy in mor-tality reduction and recurrence rates. TheXingnao Kaiqiao needling method was signiifcantly better than that of the control treatment in reducing disability rate (RR = 0.51, 95%CI: 0.27–0.98, Z = 2.03,P 〈 0.05). CONCLUSION:TheXingnao Kaiqiao needling method has a better effect than control treatment in reducing disability rate. The long-term effect ofXingnao Kaiqiao needling against ischemic stroke is better than that of control treatment. However, the limitations of this study limit the strength of the conclusions. Randomized controlled trials with a strict, reasonable design, and multi-center, large-scale samples and follow-up are necessary to draw conclusions aboutXingnao Kaiqiao needling.
文摘The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition.The estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very poor.Totally,12 genera were recorded,of which Porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(p<0.05).The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble.The reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.
基金supported by National Natural Science Foundation of China:[Grant Number No.41471419 and No.31971579].
文摘The Yellow River Delta(YRD)has China's largest artificial Robinia pseudoacacia forest,which was planted in the late 1970s and suffered extensive dieback in the 1990s.The health grade of the R.pseudoacacia forest(named canopy vigor grade,CVG)could be achieved by using high-resolution images and canopy vigor indicators(CVIs).However,a previous study showed that there was no significant correlation between CVG and the field-estimated aboveground biomass(AGB)of R.pseudoacacia forest.Therefore,this study aims to construct forest health indicators(FHIs)based on canopy spatial structure parameters extracted from LiDAR.The FHIs included Weibull_α(the scale parameter of the Weibull density function that reflects the shape of the tree canopy),VCI(vertical complexity index),sdCC(the standard deviation of canopy cover),H99(the 99th percentile height)and cvLAD(the coefficient of variation of leaf area density),and could significantly distinguish three forest health grades(FHG)(p<0.05).The FHG was positively correlated with forest AGB(rs=0.51,p=0.004),and the similarity value with CVG was 63.33%.The results of this study confirmed that the FHIs can reflect both canopy vigor and tree productivity,and distinguish forest health status without prior classification information.
文摘This paper analyzes the impact of health indicators on an individual's trip and mode choices to out-patient care facilities.The study's focus is an out-patient trip to a health care facility,and the source of data is the China Health and Retirement Longitudinal Study(CHARLS)for 2011.2013 and 2015.Based on a random utility framework,the study finds that making a rip to ureat an ilness or for a check-up increases the likelihood of an out-patient trip by 52 and 31 probability points,respectively.Out-patient visits for which in-surance is not relevant,When the individual pays most of the out:of-pocket costs and when the facility is a public facility are also important factors.Diagnosed and other per-sonal health factors have some but much more modest effects on one's trip choice.The analysis also identifies differential modal impacts of health indicators.A series of robustness tests generally confirm the results and identify areas for further research.Including a no-trip option,the biannual sunvey and infrequent out-patient trip-making mitigate endogeneity concerns.The analysis has broad health policy and transportation implications for an ageing population whose share is increasing.
文摘Objective:The purpose of this study was to understand the health-related behaviors in children of ethnic minorities and Han nationality so as to provide a basis for formulating a health promotion plan,reasonably allocating health resources,and improving health conditions of the entire population of children.Methods:The selection and processing of study subjects,as well as health-related behaviors,were based on the 2009 Chinese Health and Nutrition Survey(CHNS)data.A total of 867 children were involved in this study,including 762 Han children and 105 minority children.Comparative analysis was conducted on the reported ratio of health-related behaviors,including society and family variation,as well as dietary habit variation,and health condition scores.Results:A comparison on health-related behaviors between ethnic minority and Han children indicated the following:with respect to society and family variation,statistical significance(P<0.05)existed between the two groups in health-related behaviors influenced by parents who did or did not stay at home,level of education,and medical insurance status;and with respect to dietary habit variation,statistical significance(P<0.05)existed in the differences of dietary habits between the two groups.Moreover,differences in the weight-forage Z score(WAZ),weight-forheight Z score(WHZ),and body mass index-for-age Z score(BAZ)between the two groups were statistically significant(P<0.05).Conclusion:Health-related behavioral norms and health conditions of ethnic minority children should be further improved.Increased health awareness of families with children and health care system development should be stressed to elevate the health level of the entire population of children in China.
基金Coordenação de Aperfeiçoamento de Pessoal de Nível Superior(CAPES),Conselho Nacional de Desenvolvi-mento Científico e Tecnológico(CNPQ),and Fundação de AmparoàPesquisa do Estado de Alagoas(FAPEAL).
文摘Background:In Brazil,the Ministry of Health(MH)monitors leprosy using 15 indicators,with the aim of imple-menting and evaluating evidence-based public policies.However,an excessive number of variables can compli-cate the definition of objectives and verification of epidemiological goals.Methods:In this paper,we develop the Global Leprosy Assessment Index(GLAI),a composite measure that integrates two key dimensions for the control the disease:epidemiological and operational.Using a confirmatory factor analysis model to examine 2020 state-level data,we have standardized GLAI to a range of 0 to 1.Results:Higher values within this range indicate a greater severity of the disease.The mean value of the GLAI was 0.67,with a standard deviation of 0.22.Roraima has the highest value,followed by Paraíba with 0.88 while Tocantins records the lowest value of the indicator,followed by Mato Grosso with 0.14.The epidemiological and operational indicators have a positive but statistically insignificant correlation(r=0.25;p-value=0.20).Conclusions:The development of evidence-based public policies depends on the availability of valid and reliable indicators.The GLAI presented in this paper is easily reproducible and can be used to monitor the disease with disaggregated information.Furthermore,the GLAI has the potential to serve as a more robust parameter for evaluating the impact of actions designed to eradicate leprosy in Brazil.
基金This work was supported by the Ministry of Education,Youth and Sports of the Czech Republic within the National Programme for Sustainability I[grant number LO1415]partly by EEA Grants if Iceland,Liechtenstein and Norway[grant number EHP-CZ02-OV-1-019-2014].
文摘The study investigates the potential of UAV-based remote sensing technique for monitoring of Norway spruce health condition in the affected forest areas.The objectives are:(1)to test the applicability of UAV visible an near-infrared(VNIR)and geometrical data based on Z values of point dense cloud(PDC)raster to separate forest species and dead trees in the study area;(2)to explore the relationship between UAV VNIR data and individual spruce health indicators from field sampling;and(3)to explore the possibility of the qualitative classification of spruce health indicators.Analysis based on NDVI and PDC raster was successfully applied for separation of spruce and silver fir,and for identification of dead tree category.Separation between common beech and fir was distinguished by the object-oriented image analysis.NDVI was able to identify the presence of key indicators of spruce health,such as mechanical damage on stems and stem resin exudation linked to honey fungus infestation,while stem damage by peeling was identified at the significance margin.The results contributed to improving separation of coniferous(spruce and fir)tree species based on VNIR and PDC raster UAV data,and newly demonstrated the potential of NDVI for qualitative classification of spruce trees.The proposed methodology can be applicable for monitoring of spruce health condition in the local forest sites.
基金supported by the National Natural Science Foundation of China (No. 51175502)
文摘In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators (Cls) are presented, and the optimal Cls set is selected by comparing their test statistics according to Mann-Kendall test. Afterwards, the selected CIs are used to generate a health indicator (HI) through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitor- ing of helicopter transmission systems, and it is effective to reduce the test cost and improve the system's reliability.