368 research outputs found

    Management of early failure detection of production process : the case of the clutch shaft alignment using LSTM deep learning algorithm

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    PURPOSE: In this paper the neural networks model based on long short-term memory (LSTM) for early failure detection of the clutch shaft alignment system is developed. This issue is of particular importance when assessing the condition of the tool and predicting its durability, which are keys to the reliability and quality of the production process.DESIGN/METHODOLOGY/APPROACH: Based on real fault data of the measuring system, 500 clutch fault runs were simulated. Then, the time of failure was modelled with two neural networks, the conventional neural network of the ANN and the LSTM deep learning network. The study examined and compared the effectiveness and quality of both networks in the context of fault prediction.PRACTICAL IMPLICATIONS: In vibroacoustic diagnostics, we often deal with machines operating in various conditions, which makes it difficult to diagnose them using standard methods. In such cases, spectral methods require analysis of frequency bands, which may contain other components in addition to information about the diagnosed parameter. The algorithm for predicting impending failure gives the possibility to monitor the current degradation status of the device. This makes it possible to streamline planning processes in the areas of inspection, preventive replacement of parts, warranty, service, or storage of spare parts.FINDINGS: The objective of the paper is to introduce an improved computational method for failure detection based on a deep learning algorithm. It was proven that LSTM networks are suitable for successfully solving this scope of tasks.ORIGINALITY/VALUE: The research showed that the proposed LSTM algorithm is more effective and accurate than conventional artificial neural networks (ANN) based on the multilayer perceptron model.peer-reviewe

    Influence of percutaneous pulmonary valve implantation on exercise capacity: Which group of patients benefits most from the intervention?

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    Background: The aim of the study was to evaluate the role of cardiopulmonary exercise testing (CPET) parameters in assessing exercise capacity improvement after percutaneous pulmonary valve implantation (PPVI). Additionally, it aimed to determine if there are any baseline characteristics influencing that change. Methods and results: The study comprised 32 patients (mean age 26 ± 9); 53% males; diagnosis: tetralogy of Fallot (n = 18), pulmonary atresia (n = 6), Ross procedure (n = 4), other (transposition of great arteries, pulmonary stenosis, double outlet right ventricle, common arterial trunk type II — n = 4) who underwent successful PPVI due to right ventricular out­flow tract dysfunction (predominant pulmonary regurgitation — n = 17, predominant pulmo­nary stenosis — n = 15). Treadmill CPET was performed before and a year after PPVI along with clinical evaluation, cardiac magnetic resonance and transthoracic echocardiography. Twelve months post successful PPVI (pulmonary valve competence restoration and pulmonary gradient reduction from 58.8 ± 47.1 to 26.6 ± 10.8 mm Hg) there was a significant decrease in the ventilatory equivalent for CO2 at peak exercise (EQCO2) (25.3 ± 3.3 to 24.3 ± 3.0, p = 0.04) and oxygen consumption at peak exercise (pVO2) (20.4 ± 5.0 to 22.6 ± 5.3 mL/kg/min, p = 0.04). Improved EQCO2 correlated with an increase in right and left ventricular ejection fraction (respectively R = –0.57, p = 0.002; R = –0.56, p = 0.002). In this study, no baseline factors that might affect improvement in exercise function were found. Conclusions: Successful PPVI leads to an improvement in exercise capacity and hemodynamic response to exercise. The correlation between the improvement in EQCO2 or peak VO2 and baseline characteristics was too weak to reliably identify the group of patients that will benefit from the procedur

    Feasibility of a standardized ultrasound examination in patients with rheumatoid arthritis: A quality improvement among rheumatologists cohort.

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    BACKGROUND: Quality improvement is important to facilitate valid patient outcomes. Standardized examination procedures may improve the validity of US. The aim of this study was to investigate the learning progress for rheumatologists during training of US examination of the hand in patients with rheumatoid arthritis (RA). METHODS: Rheumatologists with varying degrees of experience in US were instructed by skilled tutors. The program consisted of two days with hands-on training followed by personal US examinations performed in their individual clinics. Examinations were sent to the tutors for quality control. The US examinations were evaluated according to a scoring sheet containing 144 items. An acceptable examination was defined as > 80% correct scores. RESULTS: Thirteen rheumatologists participated in the study. They included a total of 104 patients with RA. Only few of the initial examinations were scored below 80%, and as experience increased, the scores improved (p = 0.0004). A few participants displayed decreasing scores. The mean time spent performing the standardized examination procedure decreased from 34 min to less than 10 minutes (p = 0.0001). CONCLUSION: With systematic hands-on training, a rheumatologist can achieve a high level of proficiency in the conduction of US examinations of the joints of the hand in patients with RA. With experience, examination time decreases, while the level of correctness is maintained. The results indicate that US may be applied as a valid measurement tool suitable for clinical practice and in both single- and multi-centre trials

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

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    Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

    Measurement of jet fragmentation in Pb+Pb and pppp collisions at sNN=2.76\sqrt{{s_\mathrm{NN}}} = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Search for single production of vector-like quarks decaying into Wb in pp collisions at s=8\sqrt{s} = 8 TeV with the ATLAS detector

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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