The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). ...The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). These studies incorporated many di erent models, algorithms, and techniques for modeling and assessment. In this paper, methods of RUL assessment are summarized and expounded upon using two major methods: physics model based and data driven based methods. The advantages and disadvantages of each of these methods are deliberated and compared as well. Due to the intricacy of failure mechanism in system, and di culty in physics degradation observation, RUL assessment based on observations of performance variables turns into a science in evaluating the degradation. A modeling method from control systems, the state space model(SSM), as a first order hidden Markov, is presented. In the context of non-linear and non-Gaussian systems, the SSM methodology is capable of performing remaining life assessment by using Bayesian estimation(sequential Monte Carlo). Being e ective for non-linear and non-Gaussian dynamics, the methodology can perform the assessment recursively online for applications in CBM(condition based maintenance), PHM(prognostics and health management), remanufacturing, and system performance reliability. Finally, the discussion raises concerns regarding online sensing data for SSM modeling and assessment of RUL.展开更多
Based on initial discontinuity state (IDS) of material, a preliminary analytical model was presented to evaluate the effect of interaction of pitting corrosion and fatigue loading on the residual fatigue life of alumi...Based on initial discontinuity state (IDS) of material, a preliminary analytical model was presented to evaluate the effect of interaction of pitting corrosion and fatigue loading on the residual fatigue life of aluminum alloy LY12CZ. A life prediction was carried out using constant and variable amplitude loading for various pitting corrosion levels, and the prediction agreed reasonably with the available test data. The results suggest that the combination of a pit and IDS can be treated as the initial crack size. Pitting corrosion causes a significant decrease in fatigue lives with small corrosion depths. But the effect of pit on fatigue life is gradually reduced with increasing pit size. A pit with a constant depth can be applied to the model for long exposure structure. A preliminary recommendation for the pit depth is about 1 mm for LY12CZ. At last the effect of multiple-site corrosion damage (MSCD) on fatigue life was also studied, and the result shows that MSCD can decrease substantially fatigue life compared with that of a single crack.展开更多
Background: Efforts to combat tuberculosis in Nigeria focus on evaluation of strategies for treatment and prevention, with little attention paid to the impact of the burden of illness and its therapy on the HRQoL of T...Background: Efforts to combat tuberculosis in Nigeria focus on evaluation of strategies for treatment and prevention, with little attention paid to the impact of the burden of illness and its therapy on the HRQoL of TB patients. This study evaluated the quality of life (QoL) of TB patients in relation to their financial, psychological and social well-being. Method: In 2011, following an active case finding for TB in Akwa Ibom State of Nigeria, a structured questionnaire for evaluating HRQoL was distributed to TB patients who had been on treatment in four DOTs centres of the state for at least three months. The questions were to elicit responses that conveyed the respondents’ perspective of the disease. One hundred and eight TB patients (54 males and 54 females) aged 15 - 80 years were studied. Results: Negative emotions including fear, frustration and worry characterized the reactions of all subjects following news of their diagnosis with TB. However, following treatment, 62% of subjects expressed high expectation of being cured. Inability to continue functioning in their roles at home or as heads of households was recorded in 48.1% (52/108) and 59% (23/39) of respondents respectively and contributed to the negative emotions expressed above. Lack of basic supplies such as food and finances to meet personal and family needs constituted the most important socio-economic challenges. Socio-economic status of respondents revealed that 61% had no regular means of income with at least 94% earning less than $50 (8000 naira) a month. Subsistent farmers and petty traders constituted more than 66% of the respondents: 98% obtained less than or equivalent of high school education. Socially, all health workers and 87% of family members were sympathetic and supportive compared to friends, with 42% exhibiting stigmatization. The most frequent forms of support from family members were financial (25%) and provision of food (37%). Up to 28% were regularly prompted by family to take their medication. Conclusion: In the midst of obvious socio-economic challenges confronting TB patients in this study, the initial negative emotions declined following the supportive roles of mainly health care workers and family members. Patients were optimistic of achieving cure at the end of the treatment.展开更多
Objective: This study aimed to evaluate the immediate psychological effects of coordination exercises on women in Japan. Methods: The subjects were 17 adult women (height, 160.1 ± 5.1 cm;weight, 54.3 ± 10.5 ...Objective: This study aimed to evaluate the immediate psychological effects of coordination exercises on women in Japan. Methods: The subjects were 17 adult women (height, 160.1 ± 5.1 cm;weight, 54.3 ± 10.5 kg;age, 57.8 ± 8.3 years) living in the community and attending a fitness club. The subjects performed a coordination exercise called Life Kinetik®. The subjects responded to the Two-Dimensional Mood Scale–Short Term before and after performing 30 minutes of Life Kinetik®. The results were tabulated and four psychological states were calculated (i.e., vitality, stability, pleasure, and arousal). The pre- and post-implementation results were statistically analyzed using a corresponding t-test. Results: Significant differences were found in activation and arousal levels, but not in stability and comfort levels. Conclusion: The coordination exercise, Life Kinetik®, was found to be an exercise program with potential psychological benefits, as it could change women’s psychological condition to active and excited states.展开更多
BACKGROUND Alterations in health-related quality of life(HRQoL)and neuropsychological disorders were described in the hepatitis C virus(HCV)patients.Although several studies investigated the modifications of HRQoL aft...BACKGROUND Alterations in health-related quality of life(HRQoL)and neuropsychological disorders were described in the hepatitis C virus(HCV)patients.Although several studies investigated the modifications of HRQoL after HCV eradication,no data exists on the modifications of neuropsychological symptoms.AIM To investigate the effect of directly acting antivirals(DAAs)treatment on HRQoL and neuropsychological symptoms.METHODS Thirty nine patients with HCV infection underwent a neuropsychological assessment,including Zung-Self Depression-Rating-Scale,Spielberg State-Trait Anxiety Inventory Y1-Y2 and the Toronto-Alexithymia Scale-20 items before and after DAAs treatment.HRQoL was detected by Short-Form-36(SF-36).RESULTS All HRQoL domains,but role limitation physical and bodily pain,significantly improved after treatment.Interestingly,after DAAs treatment,all domains of HRQoL returned similar to those of controls.Each neuropsychological test significantly improved after HCV eradication.A significant correlation was observed among each psychological test and the summary components of SF-36.At multiple linear regression analysis including each psychological test as possible covariates,Zung-Self Depression Rating Scale(Zung-SDS)score was independently and significantly related to summary components of the SF-36 in the basal state and the difference between Zung-SDS score before and after treatment was the only variable significantly and independently related to the modification of HRQoL induced by the treatment.CONCLUSION Neuropsychological symptoms strongly influenced HRQoL in HCV patients and there was a significant improvement of neuropsychological tests and HRQoL after DAAs treatment.展开更多
A method is proposed to improve the accuracy of remaining useful life prediction for rolling element bearings,based on a state space model(SSM)with different degradation stages and a particle filter.The model is impro...A method is proposed to improve the accuracy of remaining useful life prediction for rolling element bearings,based on a state space model(SSM)with different degradation stages and a particle filter.The model is improved by a method based on the Paris formula and the Foreman formula allowing the establishment of different degradation stages.The remaining useful life of rolling element bearings can be predicted by the adjusted model with inputs of physical data and operating status information.The late operating trend is predicted by the use of the particle filter algorithm.The rolling bearing full life experimental data validate the proposed method.Further,the prediction result is compared with the single SSM and the Gamma model,and the results indicate that the predicted accuracy of the proposed method is higher with better practicability.展开更多
In this study, we investigated six types of mood state (tension-anxiety, depression-dejection, anger-hostility, vigor, fatigue, and confusion) using the Profile of Mood States (POMS) with 40 Japanese university studen...In this study, we investigated six types of mood state (tension-anxiety, depression-dejection, anger-hostility, vigor, fatigue, and confusion) using the Profile of Mood States (POMS) with 40 Japanese university students. We examined five main quality of life (QOL) domains (physical health, psychological health, social relationships, and environmental health) using the World Health Organization Quality of Life Scale (WHOQOL-26). We also examined the total scale score. We examined Spearman’s rank correlations between POMS mood state and QOL scores and compared male and female students’ scores. The results indicated statistically significant correlations between all six mood states and three broad WHOQOL-26 domains (physical health, psychological health, and social relationships). Moreover, the relationship between mood state and QOL showed a gender difference. There were correlations between mood states and the QOL domains of social relationships and environmental health for males. In contrast, mood state correlated with the QOL domains of physical health and psychological health in females. The findings suggest that gender-specific health provision is needed to care for young university students in Japan. However, our study has several limitations;therefore, larger-scale studies with older subjects are needed in the future.展开更多
BACKGROUND: This cross-sectional study aimed to assess the knowledge, attitude and anxiety pertaining to basic life support(BLS) and medical emergencies among interns in dental colleges of Mangalore city, Karnataka, I...BACKGROUND: This cross-sectional study aimed to assess the knowledge, attitude and anxiety pertaining to basic life support(BLS) and medical emergencies among interns in dental colleges of Mangalore city, Karnataka, India.METHODS: The study subjects comprised of interns who volunteered from the four dental colleges. The knowledge and attitude of interns were assessed using a 30-item questionnaire prepared based on the Basic Life Support Manual from American Heart Association and the anxiety of interns pertaining to BLS and medical emergencies were assessed using a State-Trait Anxiety Inventory(STAI) Questionnaire. Chi-square test was performed on SPSS 21.0(IBM Statistics, 2012) to determine statistically signifi cant differences(P<0.05) between assessed knowledge and anxiety.RESULTS: Out of 183 interns, 39.89% had below average knowledge. A total of 123(67.21%) reported unavailability of professional training. The majority(180, 98.36%) felt the urgent need of training in basic life support procedures. Assessment of stress showed a total of 27.1% participants to be above highstress level. Comparison of assessed knowledge and stress was found to be insignifi cant(P=0.983).CONCLUSION: There was an evident lack of knowledge pertaining to the management of medical emergencies among the interns. As oral health care providers moving out to the society, a focus should be placed on the training of dental interns with respect to Basic Life Support procedures.展开更多
基金Supported by Fundamental Research Funds for the Central Universities of China(Grant No.DUT17GF214)
文摘The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). These studies incorporated many di erent models, algorithms, and techniques for modeling and assessment. In this paper, methods of RUL assessment are summarized and expounded upon using two major methods: physics model based and data driven based methods. The advantages and disadvantages of each of these methods are deliberated and compared as well. Due to the intricacy of failure mechanism in system, and di culty in physics degradation observation, RUL assessment based on observations of performance variables turns into a science in evaluating the degradation. A modeling method from control systems, the state space model(SSM), as a first order hidden Markov, is presented. In the context of non-linear and non-Gaussian systems, the SSM methodology is capable of performing remaining life assessment by using Bayesian estimation(sequential Monte Carlo). Being e ective for non-linear and non-Gaussian dynamics, the methodology can perform the assessment recursively online for applications in CBM(condition based maintenance), PHM(prognostics and health management), remanufacturing, and system performance reliability. Finally, the discussion raises concerns regarding online sensing data for SSM modeling and assessment of RUL.
基金Project(50675221) supported by the National Natural Science Foundation of China
文摘Based on initial discontinuity state (IDS) of material, a preliminary analytical model was presented to evaluate the effect of interaction of pitting corrosion and fatigue loading on the residual fatigue life of aluminum alloy LY12CZ. A life prediction was carried out using constant and variable amplitude loading for various pitting corrosion levels, and the prediction agreed reasonably with the available test data. The results suggest that the combination of a pit and IDS can be treated as the initial crack size. Pitting corrosion causes a significant decrease in fatigue lives with small corrosion depths. But the effect of pit on fatigue life is gradually reduced with increasing pit size. A pit with a constant depth can be applied to the model for long exposure structure. A preliminary recommendation for the pit depth is about 1 mm for LY12CZ. At last the effect of multiple-site corrosion damage (MSCD) on fatigue life was also studied, and the result shows that MSCD can decrease substantially fatigue life compared with that of a single crack.
文摘Background: Efforts to combat tuberculosis in Nigeria focus on evaluation of strategies for treatment and prevention, with little attention paid to the impact of the burden of illness and its therapy on the HRQoL of TB patients. This study evaluated the quality of life (QoL) of TB patients in relation to their financial, psychological and social well-being. Method: In 2011, following an active case finding for TB in Akwa Ibom State of Nigeria, a structured questionnaire for evaluating HRQoL was distributed to TB patients who had been on treatment in four DOTs centres of the state for at least three months. The questions were to elicit responses that conveyed the respondents’ perspective of the disease. One hundred and eight TB patients (54 males and 54 females) aged 15 - 80 years were studied. Results: Negative emotions including fear, frustration and worry characterized the reactions of all subjects following news of their diagnosis with TB. However, following treatment, 62% of subjects expressed high expectation of being cured. Inability to continue functioning in their roles at home or as heads of households was recorded in 48.1% (52/108) and 59% (23/39) of respondents respectively and contributed to the negative emotions expressed above. Lack of basic supplies such as food and finances to meet personal and family needs constituted the most important socio-economic challenges. Socio-economic status of respondents revealed that 61% had no regular means of income with at least 94% earning less than $50 (8000 naira) a month. Subsistent farmers and petty traders constituted more than 66% of the respondents: 98% obtained less than or equivalent of high school education. Socially, all health workers and 87% of family members were sympathetic and supportive compared to friends, with 42% exhibiting stigmatization. The most frequent forms of support from family members were financial (25%) and provision of food (37%). Up to 28% were regularly prompted by family to take their medication. Conclusion: In the midst of obvious socio-economic challenges confronting TB patients in this study, the initial negative emotions declined following the supportive roles of mainly health care workers and family members. Patients were optimistic of achieving cure at the end of the treatment.
文摘Objective: This study aimed to evaluate the immediate psychological effects of coordination exercises on women in Japan. Methods: The subjects were 17 adult women (height, 160.1 ± 5.1 cm;weight, 54.3 ± 10.5 kg;age, 57.8 ± 8.3 years) living in the community and attending a fitness club. The subjects performed a coordination exercise called Life Kinetik®. The subjects responded to the Two-Dimensional Mood Scale–Short Term before and after performing 30 minutes of Life Kinetik®. The results were tabulated and four psychological states were calculated (i.e., vitality, stability, pleasure, and arousal). The pre- and post-implementation results were statistically analyzed using a corresponding t-test. Results: Significant differences were found in activation and arousal levels, but not in stability and comfort levels. Conclusion: The coordination exercise, Life Kinetik®, was found to be an exercise program with potential psychological benefits, as it could change women’s psychological condition to active and excited states.
文摘BACKGROUND Alterations in health-related quality of life(HRQoL)and neuropsychological disorders were described in the hepatitis C virus(HCV)patients.Although several studies investigated the modifications of HRQoL after HCV eradication,no data exists on the modifications of neuropsychological symptoms.AIM To investigate the effect of directly acting antivirals(DAAs)treatment on HRQoL and neuropsychological symptoms.METHODS Thirty nine patients with HCV infection underwent a neuropsychological assessment,including Zung-Self Depression-Rating-Scale,Spielberg State-Trait Anxiety Inventory Y1-Y2 and the Toronto-Alexithymia Scale-20 items before and after DAAs treatment.HRQoL was detected by Short-Form-36(SF-36).RESULTS All HRQoL domains,but role limitation physical and bodily pain,significantly improved after treatment.Interestingly,after DAAs treatment,all domains of HRQoL returned similar to those of controls.Each neuropsychological test significantly improved after HCV eradication.A significant correlation was observed among each psychological test and the summary components of SF-36.At multiple linear regression analysis including each psychological test as possible covariates,Zung-Self Depression Rating Scale(Zung-SDS)score was independently and significantly related to summary components of the SF-36 in the basal state and the difference between Zung-SDS score before and after treatment was the only variable significantly and independently related to the modification of HRQoL induced by the treatment.CONCLUSION Neuropsychological symptoms strongly influenced HRQoL in HCV patients and there was a significant improvement of neuropsychological tests and HRQoL after DAAs treatment.
文摘A method is proposed to improve the accuracy of remaining useful life prediction for rolling element bearings,based on a state space model(SSM)with different degradation stages and a particle filter.The model is improved by a method based on the Paris formula and the Foreman formula allowing the establishment of different degradation stages.The remaining useful life of rolling element bearings can be predicted by the adjusted model with inputs of physical data and operating status information.The late operating trend is predicted by the use of the particle filter algorithm.The rolling bearing full life experimental data validate the proposed method.Further,the prediction result is compared with the single SSM and the Gamma model,and the results indicate that the predicted accuracy of the proposed method is higher with better practicability.
文摘In this study, we investigated six types of mood state (tension-anxiety, depression-dejection, anger-hostility, vigor, fatigue, and confusion) using the Profile of Mood States (POMS) with 40 Japanese university students. We examined five main quality of life (QOL) domains (physical health, psychological health, social relationships, and environmental health) using the World Health Organization Quality of Life Scale (WHOQOL-26). We also examined the total scale score. We examined Spearman’s rank correlations between POMS mood state and QOL scores and compared male and female students’ scores. The results indicated statistically significant correlations between all six mood states and three broad WHOQOL-26 domains (physical health, psychological health, and social relationships). Moreover, the relationship between mood state and QOL showed a gender difference. There were correlations between mood states and the QOL domains of social relationships and environmental health for males. In contrast, mood state correlated with the QOL domains of physical health and psychological health in females. The findings suggest that gender-specific health provision is needed to care for young university students in Japan. However, our study has several limitations;therefore, larger-scale studies with older subjects are needed in the future.
文摘BACKGROUND: This cross-sectional study aimed to assess the knowledge, attitude and anxiety pertaining to basic life support(BLS) and medical emergencies among interns in dental colleges of Mangalore city, Karnataka, India.METHODS: The study subjects comprised of interns who volunteered from the four dental colleges. The knowledge and attitude of interns were assessed using a 30-item questionnaire prepared based on the Basic Life Support Manual from American Heart Association and the anxiety of interns pertaining to BLS and medical emergencies were assessed using a State-Trait Anxiety Inventory(STAI) Questionnaire. Chi-square test was performed on SPSS 21.0(IBM Statistics, 2012) to determine statistically signifi cant differences(P<0.05) between assessed knowledge and anxiety.RESULTS: Out of 183 interns, 39.89% had below average knowledge. A total of 123(67.21%) reported unavailability of professional training. The majority(180, 98.36%) felt the urgent need of training in basic life support procedures. Assessment of stress showed a total of 27.1% participants to be above highstress level. Comparison of assessed knowledge and stress was found to be insignifi cant(P=0.983).CONCLUSION: There was an evident lack of knowledge pertaining to the management of medical emergencies among the interns. As oral health care providers moving out to the society, a focus should be placed on the training of dental interns with respect to Basic Life Support procedures.
