期刊文献+
共找到2,769篇文章
< 1 2 139 >
每页显示 20 50 100
Cavitation Diagnostics Based on Self-Tuning VMD for Fluid Machinery with Low-SNR Conditions 被引量:1
1
作者 Hao Liu Zheming Tong +1 位作者 Bingyang Shang Shuiguang Tong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第4期212-226,共15页
Variational mode decomposition(VMD)is a suitable tool for processing cavitation-induced vibration signals and is greatly affected by two parameters:the decomposed number K and penalty factorαunder strong noise interf... Variational mode decomposition(VMD)is a suitable tool for processing cavitation-induced vibration signals and is greatly affected by two parameters:the decomposed number K and penalty factorαunder strong noise interference.To solve this issue,this study proposed self-tuning VMD(SVMD)for cavitation diagnostics in fluid machinery,with a special focus on low signal-to-noise ratio conditions.A two-stage progressive refinement of the coarsely located target penalty factor for SVMD was conducted to narrow down the search space for accelerated decomposition.A hybrid optimized sparrow search algorithm(HOSSA)was developed for optimalαfine-tuning in a refined space based on fault-type-guided objective functions.Based on the submodes obtained using exclusive penalty factors in each iteration,the cavitation-related characteristic frequencies(CCFs)were extracted for diagnostics.The power spectrum correlation coefficient between the SVMD reconstruction and original signals was employed as a stop criterion to determine whether to stop further decomposition.The proposed SVMD overcomes the blindness of setting the mode number K in advance and the drawback of sharing penalty factors for all submodes in fixed-parameter and parameter-optimized VMDs.Comparisons with other existing methods in simulation signal decomposition and in-lab experimental data demonstrated the advantages of the proposed method in accurately extracting CCFs with lower computational cost.SVMD especially enhances the denoising capability of the VMD-based method. 展开更多
关键词 Fluid machinery self-tuning VMD Cavitation diagnostics Hybrid optimized sparrow search algorithm
下载PDF
Mental emotional disorder is a predictor of stroke incidence in adults:Ten year results of the Bogor Cohort Study on Non-Communicable Disease Risk Factors in Indonesia 被引量:1
2
作者 Woro Riyadina Alifa Syamantha Putri +2 位作者 Sulistyowati Tuminah Ika Suswanti Yuda Turana 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2024年第8期351-357,共7页
Objective:To determine the stroke predictors for the 10-year of follow-up in Bogor City,Indonesia.Methods:The prospective study analyzed the data of 4445 stroke-free subjects aged 25 years and above that was part of&q... Objective:To determine the stroke predictors for the 10-year of follow-up in Bogor City,Indonesia.Methods:The prospective study analyzed the data of 4445 stroke-free subjects aged 25 years and above that was part of"the Bogor Cohort Study on Non-Communicable Disease Risk Factors".Data were collected by interview method with structured questionnaires,physical measurements three times a year,and laboratory examination every two years during a 10-year follow-up(2011-2021,without examination in 2020).The incidence of stroke is based on anamnesis results and examination by a neurologist.Other stroke predictor variables include characteristics,biological conditions,and risk behavior.We analysed 4445 stroke-free samples with Cox proportional hazard regression test.Results:During the 10-year observation,stroke incidence was 440 person-years per 100000 population(95%CI 370-530).During the follow-up of ten years,the main predictor of stroke was mental-emotional disorders with HR 4.2(95%CI 2.8-6.3)after adjustment by age,hypertension,obesity,abdominal obesity,and high LDL-cholesterol levels.Conclusions:Mental-emotional disorders are the strongest predictor of stroke incidence.Hence,psychological factors must be controlled in a stroke prevention program. 展开更多
关键词 ADULT COHORT Mental-emotional disorder Stroke predictor
下载PDF
System Identification and Parameter Self-Tuning Controller on Deep-Sea Mining Vehicle
3
作者 WENG Qi-wang YANG Jian-min +2 位作者 LIANG Qiong-wen MAO Jing-hang GUO Xiao-xian 《China Ocean Engineering》 SCIE EI CSCD 2023年第1期53-61,共9页
System identification is a quintessential measure for real-time analysis on kinematic characteristics for deep-sea mining vehicle, and thus to enhance the control performance and testing efficiency. In this study, the... System identification is a quintessential measure for real-time analysis on kinematic characteristics for deep-sea mining vehicle, and thus to enhance the control performance and testing efficiency. In this study, the system identification algorithm, recursive least square method with instrumental variables(IV-RLS), is tailored to model ‘Pioneer I’, a deep-sea mining vehicle which recently completed a 1305-meter-deep sea trial in the Xisha area of the South China Sea in August, 2021. The algorithm operates on the sensor data collected from the trial to obtain the vehicle’s kinematic model and accordingly design the parameter self-tuning controller. The performances demonstrate the accuracy of the model, and prove its generalization capability. With this model, the optimal controller has been designed, the control parameters have been self-tuned, and the response time and robustness of the system have been optimized,which validates the high efficiency on digital modelling for precision control of deep-sea mining vehicles. 展开更多
关键词 deep-sea mining system identification parameter self-tuning controller digital modeling
下载PDF
Self-tuning Information Fusion Kalman Predictor Weighted by Diagonal Matrices and Its Convergence Analysis 被引量:14
4
作者 DENG Zi-Li LI Chun-Bo 《自动化学报》 EI CSCD 北大核心 2007年第2期156-163,共8页
为有未知噪音统计的 multisensor 系统,使用现代时间系列分析方法,基于革新建模的动人的一般水准(麻省)的联机鉴定,并且基于为关联功能的矩阵方程的解决方案,噪音变化的评估者被获得,并且在线性最小的变化下面由斜矩阵加权的最佳... 为有未知噪音统计的 multisensor 系统,使用现代时间系列分析方法,基于革新建模的动人的一般水准(麻省)的联机鉴定,并且基于为关联功能的矩阵方程的解决方案,噪音变化的评估者被获得,并且在线性最小的变化下面由斜矩阵加权的最佳的信息熔化标准,一个自我调节的信息熔化 Kalman 预言者被介绍,它认识到自我调节的 dec 基于动态错误系统,一个新集中分析方法为自我调节的 fuser 被介绍。在一条认识的集中的一个新概念被介绍,它是比有概率一的集中弱的。如果 MA 革新模型的参数评价是一致的,那么,自我调节的熔化 Kalman 预言者将在一条认识收敛到最佳的熔化 Kalman 预言者,这严格地被证明,或与概率一,以便它有 asymptotic optimality。它能减少计算负担,并且对实时应用合适。为追踪系统的一个目标的一个模拟例子显示出它的有效性。 展开更多
关键词 人工智能 信息融合 集中分析 控制理论
下载PDF
Predictors of Abnormal Vaginal Discharge among Women of Reproductive Age in Southeast Nigeria
5
作者 Jideuma Egwim Victor Dike +5 位作者 Hope Igbonagwam Nkechinyere Oke Uzoma Amajo Akuchi Okafor Angela Izegbune Ijedimma Okafor 《International Journal of Clinical Medicine》 CAS 2024年第7期240-256,共17页
Background: An abnormal vaginal discharge is a common complaint among women of reproductive age, and it can indicate serious conditions like pelvic inflammatory disease and cervical cancer. This study aimed to assess ... Background: An abnormal vaginal discharge is a common complaint among women of reproductive age, and it can indicate serious conditions like pelvic inflammatory disease and cervical cancer. This study aimed to assess the predictors of abnormal vaginal discharge in women of reproductive age group in Imo State, Southeast Nigeria. Methods: A cross-sectional study was conducted among 368 women of reproductive age group attending the clinic at Federal University Teaching Hospital Owerri, in Imo State, Nigeria. Respondents were recruited using a systematic sampling technique. Data were collected using a pre-tested interviewer-administered questionnaire. Multivariable analysis was performed to determine predictors of abnormal vaginal discharge. Statistical significance was set at p Results: The mean age of the respondents was 30 ±  4.5 years. Predictors of abnormal vaginal discharge were: age 36 - 45 years (OR: 4.5;95% C.I: 1.023 - 8.967, p = 0.041), being a student (OR: 2.4: 95% C.I: 1.496 - 7.336, p = 0.003), use of oral contraceptives (OR: 3.4;95% C.I: 1.068 - 6.932, p = 0.010), use of water cistern (OR: 4.7;C.I: 1.654 - 5.210, p = 0.028) anal hygiene practices (OR: 2.7;95% C.I: 1.142 - 4.809, p Conclusion: These findings suggest that targeted sexual and reproductive health interventions should be provided to reduce the risk of abnormal vaginal discharge in women of reproductive age group. 展开更多
关键词 predictorS ABNORMAL VAGINAL DISCHARGE
下载PDF
Echocardiographic predictors and associated outcomes of multiple vegetations in infective endocarditis:A pilot study
6
作者 Ajay Kumar Mishra Kannu Bansal +6 位作者 Ibragim Al-Seykal Pradnya B Bhattad Anu Anna George Anil Jha Nitish Sharma Jennifer Sargent Mark J Kranis 《World Journal of Cardiology》 2024年第6期318-328,共11页
BACKGROUND Infective endocarditis(IE)is a life-threatening infection with an annual mortality of 40%.Embolic events reported in up to 80%of patients.Vegetations of>10 mm size are associated with increased embolic e... BACKGROUND Infective endocarditis(IE)is a life-threatening infection with an annual mortality of 40%.Embolic events reported in up to 80%of patients.Vegetations of>10 mm size are associated with increased embolic events and poor prognosis.There is a paucity of literature on the association of multiple vegetations with outcome.AIM To study the echocardiographic(ECHO)features and outcomes associated with the presence of multiple vegetations.METHODS In this retrospective,single-center,cohort study patients diagnosed with IE were recruited from June 2017 to June 2019.A total of 84 patients were diagnosed to have IE,of whom 67 with vegetation were identified.Baseline demographic,clinical,laboratory,and ECHO parameters were reviewed.Outcomes that were studied included recurrent admission,embolic phenomenon,and mortality.RESULTS Twenty-three(34%)patients were noted to have multiple vegetations,13(56.5%)were male and 10(43.5%)were female.The mean age of these patients was 50.Eight(35%)had a prior episode of IE.ECHO features of moderate to severe valvular regurgitation[odds ratio(OR)=4],presence of pacemaker lead(OR=4.8),impaired left ventricle(LV)relaxation(OR=4),and elevated pulmonary artery systolic pressure(PASP)(OR=2.2)are associated with higher odds of multiple vegetations.Of these moderate to severe valvular regurgitation(P=0.028),pacemaker lead(P=0.039)and impaired relaxation(P=0.028)were statistically significant.These patients were noted to have an increased association of recurrent admissions(OR=3.6),recurrent bacteremia(OR=2.4),embolic phenomenon(OR=2.5),intensive care unit stay(OR=2.8),hypotension(OR=2.1),surgical intervention(OR=2.8)and device removal(OR=4.8).Of this device removal(P=0.039)and recurrent admissions(P=0.017)were statistically significant.CONCLUSION This study highlights the associations of ECHO predictors and outcomes in patients with IE having multiple vegetations.ECHO features of moderate to severe regurgitation,presence of pacemaker lead,impaired LV relaxation,and elevated PASP and outcomes including recurrent admissions and device removal were found to be associated with multiple vegetations. 展开更多
关键词 ENDOCARDITIS ECHOCARDIOGRAPHY VEGETATIONS predictorS OUTCOME
下载PDF
Predictors of Fatal Outcome in Hospitalised Adult Patients with Acute Kidney Injury at Two Tertiary Hospitals in Sub-Saharan Africa
7
作者 Denis Georges Teuwafeu Fombo Enjeh Jabbossung +4 位作者 Maimouna Mahamat Eric Aristide Nono Tomta Mbapah Leslie Tasha Francois Kaze Folefack Gloria Ashuntantang 《Open Journal of Nephrology》 2024年第1期86-103,共18页
Introduction: Data on mortality in acute kidney injury (AKI) derives from high-income countries where AKI is hospital-acquired and occurs in elderly patients with a high burden of cardiovascular disease. In sub-Sahara... Introduction: Data on mortality in acute kidney injury (AKI) derives from high-income countries where AKI is hospital-acquired and occurs in elderly patients with a high burden of cardiovascular disease. In sub-Saharan Africa (SSA), AKI is community-acquired occurring in healthy young adults. We aimed to identify predictors of fatal outcomes in patients with AKI in two tertiary hospitals in Cameroon. Methods: Medical records of adults with confirmed AKI, from January 2018 to March 2020 were retrieved. The outcomes of interest were in-hospital deaths and presumed causes of death. We used multiple logistic regressions modeling to identify predictors of death. The study was approved by the ethics boards of both hospitals. Values were considered significant for a p-value of 0.05. Results: We included 285 patient records (37.2% females). The mean (SD) age was 50.1 (19.0) years. Hypertension (n = 97, 34.0%), organ failure (n = 88, 30.9%), and diabetes (n = 60, 21.1%) were the main comorbidities. The majority of patients had community-acquired AKI (78.6%, n = 224), were KDIGO stage 3 (88.8%, n = 253), and needed dialysis (52.6%, n = 150). Up to 16.7% (n = 25) did not receive what was needed. The in-hospital mortality rate was 29.1% (n = 83). Lack of access to dialysis (OR = 27.8;CI: 5.2 - 149.3, p = 0.001), hypotension (OR = 11.8;CI: 1.3 - 24.8;p = 0.001) and ICU admission (OR = 5.7;CI: 1.3 - 24.8, p = 0.001) were predictors of mortality. The presence of co-morbidities or underlying diseases (n = 46, 55%) were the main causes of death. Conclusions: In-hospital AKI mortality is high, as in other low- and middle-income economies. Lack of access to dialysis and the severity of the underlying illness are major predictors of death. 展开更多
关键词 predictorS Fatal Outcome Acute Kidney Injury Tertiary Hospital
下载PDF
Predictors of portal vein thrombosis after splenectomy in patients with cirrhosis
8
作者 Ting Li Li-Li Wang +4 位作者 Ya-Ping Li Jian Gan Xi-Sheng Wei Xiao-Rong Mao Jun-Feng Li 《World Journal of Hepatology》 2024年第2期241-250,共10页
BACKGROUND Portal vein thrombosis(PVT)is a commonthsn complication after splenectomy in patients with cirrhosis.However,the predictors of postoperative PVT are not known.AIM To investigate the predictors of PVT after ... BACKGROUND Portal vein thrombosis(PVT)is a commonthsn complication after splenectomy in patients with cirrhosis.However,the predictors of postoperative PVT are not known.AIM To investigate the predictors of PVT after splenectomy in patient with cirrhosis.METHODS A total of 45 patients with cirrhosis who underwent splenectomy were consecutively enrolled from January 2017 to December 2018.The incidence of PVT at 1 months,3 months,and 12 months after splenectomy in patients with cirrhosis was observed.The hematological indicators,biochemical and coagulation parameters,and imaging features were recorded at baseline and at each observation point.The univariable,multivariable,receiver operating characteristic curve and timedependent curve analyses were performed.RESULTS The cumulative incidence of PVT was 40.0%,46.6%,and 48.9%at 1 months,3 months,and 12 months after splenectomy.Multivariable analysis showed that portal vein diameter(PVD)≥14.5 mm and monthsdel end-stage liver disease(MELD)score>10 were independent predictors of PVT at 1 months,3 months,and 12 months after splenectomy(P<0.05).Time-dependent curve showed that the cumulative incidence of PVT was significantly different between patients with MELD score≤10 and>10(P<0.05).In addition,the cumulative incidence of PVT in the PVD≥14.5 mm group was significantly higher than that in the PVD<14.5 mm group(P<0.05).CONCLUSION Wider PVD and MELD score>10 were independent predictors of PVT at 1 months,3 months,and 12 months after splenectomy in patient with cirrhosis. 展开更多
关键词 CIRRHOSIS SPLENECTOMY Portal vein thrombosis predictorS
下载PDF
Rates, predictors, and causes of readmission after transcatheter aortic valve replacement in patients with chronic kidney disease
9
作者 Taha Teaima Gianfranco Bittar Carlini +5 位作者 Rohan A Gajjar Imran Aziz Sami J Shoura Abdul-Rahim Shilbayeh Naim Battikh Tareq Alyousef 《World Journal of Cardiology》 2024年第7期402-411,共10页
BACKGROUND Transcatheter aortic valve replacement(TAVR)is a revolutionary procedure for severe aortic stenosis.The coexistence of chronic kidney disease(CKD)and TAVR introduces a challenge that significantly impacts p... BACKGROUND Transcatheter aortic valve replacement(TAVR)is a revolutionary procedure for severe aortic stenosis.The coexistence of chronic kidney disease(CKD)and TAVR introduces a challenge that significantly impacts patient outcomes.AIM To define readmission rates,predictors,and causes after TAVR procedure in CKD stage 1-4 patients.METHODS We used the national readmission database 2018 and 2020 to look into readmission rates,causes and predictors after TAVR procedure in patients with CKD stage 1-4.RESULTS Out of 24758 who underwent TAVR and had CKD,7892(32.4%)patients were readmitted within 90 days,and had higher adjusted odds of being females(adjusted odds ratio:1.17,95%CI:1.02-1.31,P=0.02)with longer length of hospital stay>6 days,and more comorbidities including but not limited to diabetes mellitus,anemia,and congestive heart failure(CHF).CONCLUSION Most common causes of readmission included CHF(18.0%),sepsis,and complete atrioventricular block.Controlling readmission predictors with very close followup is warranted to prevent such high rate of readmission. 展开更多
关键词 Chronic kidney disease Transcatheter aortic valve replacement READMISSION predictorS Rates
下载PDF
Heterogeneously elevated branched-chain/aromatic amino acids among new-onset type-2 diabetes mellitus patients are potentially skewed diabetes predictors
10
作者 Min Wang Yang Ou +7 位作者 Xiang-Lian Yuan Xiu-Fang Zhu Ben Niu Zhuang Kang Bing Zhang Anwar Ahmed Guo-Qiang Xing Heng Su 《World Journal of Diabetes》 SCIE 2024年第1期53-71,共19页
BACKGROUND The lack of specific predictors for type-2 diabetes mellitus(T2DM)severely impacts early intervention/prevention efforts.Elevated branched-chain amino acids(BCAAs:Isoleucine,leucine,valine)and aromatic amin... BACKGROUND The lack of specific predictors for type-2 diabetes mellitus(T2DM)severely impacts early intervention/prevention efforts.Elevated branched-chain amino acids(BCAAs:Isoleucine,leucine,valine)and aromatic amino acids(AAAs:Tyrosine,tryptophan,phenylalanine)show high sensitivity and specificity in predicting diabetes in animals and predict T2DM 10-19 years before T2DM onset in clinical studies.However,improvement is needed to support its clinical utility.AIM To evaluate the effects of body mass index(BMI)and sex on BCAAs/AAAs in new-onset T2DM individuals with varying body weight.METHODS Ninety-seven new-onset T2DM patients(<12 mo)differing in BMI[normal weight(NW),n=33,BMI=22.23±1.60;overweight,n=42,BMI=25.9±1.07;obesity(OB),n=22,BMI=31.23±2.31]from the First People’s Hospital of Yunnan Province,Kunming,China,were studied.One-way and 2-way ANOVAs were conducted to determine the effects of BMI and sex on BCAAs/AAAs.RESULTS Fasting serum AAAs,BCAAs,glutamate,and alanine were greater and high-density lipoprotein(HDL)was lower(P<0.05,each)in OB-T2DM patients than in NW-T2DM patients,especially in male OB-T2DM patients.Arginine,histidine,leucine,methionine,and lysine were greater in male patients than in female patients.Moreover,histidine,alanine,glutamate,lysine,valine,methionine,leucine,isoleucine,tyrosine,phenylalanine,and tryptophan were significantly correlated with abdominal adiposity,body weight and BMI,whereas isoleucine,leucine and phenylalanine were negatively correlated with HDL.CONCLUSION Heterogeneously elevated amino acids,especially BCAAs/AAAs,across new-onset T2DM patients in differing BMI categories revealed a potentially skewed prediction of T2DM development.The higher BCAA/AAA levels in obese T2DM patients would support T2DM prediction in obese individuals,whereas the lower levels of BCAAs/AAAs in NW-T2DM individuals may underestimate T2DM risk in NW individuals.This potentially skewed T2DM prediction should be considered when BCAAs/AAAs are to be used as the T2DM predictor. 展开更多
关键词 Hyperaminoacidemia Branched-chain/aromatic amino acids New-onset type-2 diabetes predictor Obesity SEX
下载PDF
Depression&Anxiety Among Women in Northern Kenya:Sociodemographic Predictors
11
作者 Gladys Kabura Mwangi 《Psychology Research》 2024年第2期57-63,共7页
This article documents socio-demographic predictors of anxiety and depression among Maasai women in resource poor settings in Northern Kenya.These findings emerged from the findings of a dissertation research that aim... This article documents socio-demographic predictors of anxiety and depression among Maasai women in resource poor settings in Northern Kenya.These findings emerged from the findings of a dissertation research that aimed to establish the treatment effectiveness of an eclectic model of psychoeducation(PE)in treating depressive and anxiety symptoms among the women.The study adopted a quasi-experimental research design which had an experimental group(EG)and control group(CG).The population for the study was 686 female members of Conservation Enterprise Groups(CEG)in Laikipia County,from which a sample of 200 were recruited for the study(EG,n=100 and CG,n=100),at 80%power and 30%effective size.The Beck’s Depression Inventory(BDI)and Beck’s Anxiety Inventory(BAI)tools were used to assess the symptoms of depression and anxiety,respectively.The PE was provided as an intervention treatment to the EG at the middle and end of the study,after which the respondents were tested for symptoms of depression.The study established the prevalence of depression as 26.7%and 31.3%for anxiety and disorders,among women in the region.Data was analyzed using SPSS Version 21.0. 展开更多
关键词 SOCIODEMOGRAPHIC ANXIETY DEPRESSION predictorS Maasai women Northern Kenya
下载PDF
Predictors of stricture after endoscopic submucosal dissection of the esophagus and steroids application
12
作者 Qing-Xia Wang Yuan Ding +2 位作者 Qi-Liu Qian Yin-Nan Zhu Rui-Hua Shi 《World Journal of Gastrointestinal Endoscopy》 2024年第9期509-518,共10页
BACKGROUND Endoscopic submucosal dissection(ESD)is a reliable method to resect early esophageal cancer.Esophageal stricture is one of the major complications after ESD of the esophagus.Steroid prophylaxis for esophage... BACKGROUND Endoscopic submucosal dissection(ESD)is a reliable method to resect early esophageal cancer.Esophageal stricture is one of the major complications after ESD of the esophagus.Steroid prophylaxis for esophageal strictures,particularly local injection of triamcinolone acetonide(TA),is a relatively effective method to prevent esophageal strictures.However,even with steroid prophylaxis,stenosis still occurs in up to 45%of patients.Predicting the risk of stenosis formation after local TA injection would enable additional interventions in risky patients.AIM To identify the predictors of esophageal strictures after steroids application.METHODS Patients who underwent esophageal ESD and steroid prophylaxis and who were comprehensively assessed for lesion-and ESD-related factors at Southeast University Affiliated Zhongda Hospital between February 2018 and March 2023 were included in the study.The univariate and multivariate regression analyses were conducted to identify the predictors of stricture among patients undergoing steroid prophylaxis.RESULTS A total of 120 patients were included in the analysis.In the oral prednisone and oral prednisone combined with local tretinoin injection groups,the stenosis rates were 44/53(83.0%)and 56/67(83.6%),respectively.Among them,univariate analysis showed that the lesion circumference(P=0.01)and submucosal injection solution(P=0.04)showed significant correlation with the risk of stenosis formation.Logistic regression analyses were then performed using predictors that were significant in the univariate analyses and combined with known predictors from previous reports,such as additional chemoradiotherapy and tumor location.We identified a lesion circumference<5/6(OR=0.19;P=0.02)and submucosal injection of sodium hyaluronate(OR=0.15;P=0.03)as independent predictors of on esophageal stricture formation.CONCLUSION Steroid prophylaxis effectively prevents stenosis.Moreover,the lesion circumference and submucosal injection of sodium hyaluronate were independent predictors of esophageal strictures.Additional interventions should be considered in high-risk patients. 展开更多
关键词 Endoscopic submucosal dissection Esophageal stricture Oral steroids Triamcinolone acetonide predictorS
下载PDF
Time to recovery from severe pneumonia and its predictors among pediatric patients admitted in Mizan-Tepi University Teaching Hospital,South West Ethiopia,2022
13
作者 Belete Fenta Kebede Aynalem Yetwale Hiwot +2 位作者 Tsegaw Biyazin Tesfa Yalemtsehay Dagnaw Genie Nigatu Dessalegn Mulu 《Frontiers of Nursing》 2024年第3期343-353,共11页
Objective:Despite trials and programs for the prevention of childhood mortality due to pneumonia,Ethiopia is among the top five countries with the highest number of deaths due to pneumonia.Although the prevalence of p... Objective:Despite trials and programs for the prevention of childhood mortality due to pneumonia,Ethiopia is among the top five countries with the highest number of deaths due to pneumonia.Although the prevalence of pneumonia has increased in the abovementioned trials,little is known about the recovery time from severe pneumonia and its predictors in the study area.Therefore,this study aimed to assess the time to recovery from severe pneumonia and its predictors among pediatric patients admitted to Mizan-Tepi University Teaching Hospital,Ethiopia,in 2022.Methods:A total of 591 children admitted for severe pneumonia were selected using simple random sampling.Data were entered into Epi-data version 4.4.2.1 and expor ted to STATA version 14 for analysis,and the assumptions of Cox propor tional hazard models and goodness of fit were assessed through Shoenfeld residual and Cox-Snell residual,respectively.Bivariate and multivariable Cox regression models were used to identify the predictors of mor tality.Results:This study revealed that 91.54%(95%confidence interval[CI]:89.00–93.53)of participants recovered with an incidence rate of 24.10(95%CI:22.15–26.21)per 100 person-day–observations.The hmedian recovery time of children was 4 days(95%CI:2–6).Children who were not exclusively breastfed(AHR=1.3;95%CI:1.03–1.66),who had a history of inability to suck/feed(AHR=0.81;95%CI:0.65–0.99)were independent predictors of the time to recovery.Conclusions:Children with severe pneumonia who had not exclusively breastfed and who had a history of inability to suck/feed were independent predictors of time to recovery.Therefore,all stakeholders and concerned health care providers should focus more on early diagnosis and management and hasten early recovery based on the identified factors. 展开更多
关键词 Mizan-Tepi University Teaching Hospital pediatric patients predictorS severe pneumonia Southwest Ethiopia time to recovery
下载PDF
A Full Predictor-Corrector Finite Element Method for the One-Dimensional Heat Equation with Time-Dependent Singularities
14
作者 Jake L. Nkeck 《Journal of Applied Mathematics and Physics》 2024年第4期1364-1382,共19页
The energy norm convergence rate of the finite element solution of the heat equation is reduced by the time-regularity of the exact solution. This paper presents an adaptive finite element treatment of time-dependent ... The energy norm convergence rate of the finite element solution of the heat equation is reduced by the time-regularity of the exact solution. This paper presents an adaptive finite element treatment of time-dependent singularities on the one-dimensional heat equation. The method is based on a Fourier decomposition of the solution and an extraction formula of the coefficients of the singularities coupled with a predictor-corrector algorithm. The method recovers the optimal convergence rate of the finite element method on a quasi-uniform mesh refinement. Numerical results are carried out to show the efficiency of the method. 展开更多
关键词 SINGULARITIES Finite Element Methods Heat Equation predictor-Corrector Algorithm
下载PDF
Experimental investigation of a passive self-tuning resonator based on a beam-slider structure 被引量:5
15
作者 Liuding Yu Lihua Tang Tiejun Yang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2019年第5期1079-1092,共14页
This work investigates a self-tuning resonator composed of a slender clamped-clamped steel beam and a freely movable slider.The clamped-clamped beam exhibits hardening nonlinearity when it vibrates in large amplitude,... This work investigates a self-tuning resonator composed of a slender clamped-clamped steel beam and a freely movable slider.The clamped-clamped beam exhibits hardening nonlinearity when it vibrates in large amplitude,providing a broad bandwidth of dynamic response.The moving slider changes the mass distribution of the whole structure,and provides a passive self-tuning approach for capturing the high-energy orbit of the structure.In the case without inclination,adequate inertial force that mainly depends on the vibration amplitude of the beam and the position of the slider can drive the slider to move from the side toward the centre of the beam.This movement amplifies the beam response when the excitation frequency is below 37 Hz in our prototyped device.In the multi-orbit frequency range(28-37 Hz),the self-tuning and magnification of beam response can be achieved when the slider is initially placed in an appropriate position on the beam.Once the beam is disturbed,however,the desired response in the high-energy orbit can be lost easily and cannot be reacquired without external assistance.In an improved design with a small inclination,the introduced small gravitational component enables the slider to move from the higher side toward the lower side when the beam amplitude is small.This property sacrifices the less efficient self-tuning region below 25 Hz,but can enable the beam to acquire and maintain the high-energy orbit response in the multi-orbit frequency range(28-39 Hz),which is resistant to disturbance.The proposed resonator in this paper not only broadens the frequency bandwidth of dynamic response,but also enables capture and maintenance of the high-energy orbit in a completely passive way.Such a passive self-tuning structure presents an advantage in the design of broadband vibration energy-harvesting systems. 展开更多
关键词 PASSIVE self-tuning Vibration energy HARVESTER Nonlinearity Beam-slider STRUCTURE
下载PDF
Fuzzy self-tuning PID control of the operation temperatures in a two-staged membrane separation process 被引量:8
16
作者 Lei Wang Wencai Du +1 位作者 Hai Wang Hong Wu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2008年第4期409-414,共6页
A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As t... A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As the conventional PID controller is difficult to make the operation temperatures steady, a fuzzy self-tuning PID control algorithm is proposed. The application shows that the algorithm is effective, the operation temperatures of both stages can be controlled steadily, and the operation flexibility and adaptability of the hydrogen recovery unit are enhanced with safety. This study lays a foundation to optimize the control of the membrane separation process and thus ensure the membrane performance. 展开更多
关键词 membrane separation hydrogen recovery operation temperature fuzzy self-tuning PID control
下载PDF
Position Control of a Flexible Manipulator Using a New Nonlinear Self-Tuning PID Controller 被引量:10
17
作者 Santanu Kumar Pradhan Bidyadhar Subudhi 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2020年第1期136-149,共14页
In this paper, a new nonlinear self-tuning PID controller(NSPIDC) is proposed to control the joint position and link deflection of a flexible-link manipulator(FLM) while it is subjected to carry different payloads. Si... In this paper, a new nonlinear self-tuning PID controller(NSPIDC) is proposed to control the joint position and link deflection of a flexible-link manipulator(FLM) while it is subjected to carry different payloads. Since, payload is a critical parameter of the FLM whose variation greatly influences the controller performance. The proposed controller guarantees stability under change in payload by attenuating the non-modeled higher order dynamics using a new nonlinear autoregressive moving average with exogenous-input(NARMAX) model of the FLM. The parameters of the FLM are identified on-line using recursive least square(RLS) algorithm and using minimum variance control(MVC) laws the control parameters are updated in real-time. This proposed NSPID controller has been implemented in real-time on an experimental set-up. The joint tracking and link deflection performances of the proposed adaptive controller are compared with that of a popular direct adaptive controller(DAC). From the obtained results, it is confirmed that the proposed controller exhibits improved performance over the DAC both in terms of accurate position tracking and quick damping of link deflections when subjected to variable payloads. 展开更多
关键词 Flexible-link manipulator position control self-tuning control NARMAX trajectory tracking
下载PDF
A Real Time Self-Tuning Motion Controller for Mobile Robot Systems 被引量:6
18
作者 Mohamed Boukens Abdelkrim Boukabou Mohammed Chadli 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2019年第1期84-96,共13页
This paper proposes an intelligent controller for motion control of robotic systems to obtain high precision tracking without the need for a real-time trial and error method.In addition, a new self-tuning algorithm ha... This paper proposes an intelligent controller for motion control of robotic systems to obtain high precision tracking without the need for a real-time trial and error method.In addition, a new self-tuning algorithm has been developed based on both the ant colony algorithm and a fuzzy system for real-time tuning of controller parameters. Simulations and experiments using a real robot have been addressed to demonstrate the success of the proposed controller and validate the theoretical analysis. Obtained results confirm that the proposed controller ensures robust performance in the presence of disturbances and parametric uncertainties without the need for adjustment of control law parameters by a trial and error method. 展开更多
关键词 Learning and adaptive SYSTEMS motion CONTROL METAHEURISTIC robust CONTROL real-time tuning self-tuning WHEELED mobile robot
下载PDF
SELF-TUNING WEIGHTED MEASUREMENT FUSION WHITE NOISE DECONVOLUTION ESTIMATOR 被引量:2
19
作者 Sun Xiaojun Deng Zili 《Journal of Electronics(China)》 2010年第1期51-59,共9页
For the multi-sensor linear discrete time-invariant stochastic systems with correlated measurement noises and unknown noise statistics,an on-line noise statistics estimator is obtained using the correlation method.Sub... For the multi-sensor linear discrete time-invariant stochastic systems with correlated measurement noises and unknown noise statistics,an on-line noise statistics estimator is obtained using the correlation method.Substituting it into the optimal weighted fusion steady-state white noise deconvolution estimator based on the Kalman filtering,a self-tuning weighted measurement fusion white noise deconvolution estimator is presented.By the Dynamic Error System Analysis(DESA) method,it proved that the self-tuning fusion white noise deconvolution estimator converges to the steady-state optimal fusion white noise deconvolution estimator in a realization.Therefore,it has the asymptotically global optimality.A simulation example for the tracking system with 3 sensors and the Bernoulli-Gaussian input white noise shows its effectiveness. 展开更多
关键词 Multi-sensor information fusion self-tuning fuser White noise deconvolution Global optimality CONVERGENCE
下载PDF
Self-tuning weighted measurement fusion Kalman filter and its convergence 被引量:2
20
作者 Chenjian RAN,Zili DENG (Department of Automation,Heilongjiang University,Harbin Heilongjiang 150080,China) 《控制理论与应用(英文版)》 EI 2010年第4期435-440,共6页
For multisensor systems,when the model parameters and the noise variances are unknown,the consistent fused estimators of the model parameters and noise variances are obtained,based on the system identification algorit... For multisensor systems,when the model parameters and the noise variances are unknown,the consistent fused estimators of the model parameters and noise variances are obtained,based on the system identification algorithm,correlation method and least squares fusion criterion.Substituting these consistent estimators into the optimal weighted measurement fusion Kalman filter,a self-tuning weighted measurement fusion Kalman filter is presented.Using the dynamic error system analysis (DESA) method,the convergence of the self-tuning weighted measurement fusion Kalman filter is proved,i.e.,the self-tuning Kalman filter converges to the corresponding optimal Kalman filter in a realization.Therefore,the self-tuning weighted measurement fusion Kalman filter has asymptotic global optimality.One simulation example for a 4-sensor target tracking system verifies its effectiveness. 展开更多
关键词 Multisensor weighted measurement fusion Fused parameter estimator Fused noise variance estimator self-tuning fusion Kalman filter Asymptotic global optimality CONVERGENCE
下载PDF
上一页 1 2 139 下一页 到第
使用帮助 返回顶部