The Experts below are selected from a list of 103875 Experts worldwide ranked by ideXlab platform
Lingli Cui - One of the best experts on this subject based on the ideXlab platform.
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improved fault size estimation method for rolling element bearings based on concatenation dictionary
IEEE Access, 2019Co-Authors: Lingli Cui, Xin Wang, Huaqing WangAbstract:This paper offers a new perspective on the vibrations of discrete bearing faults by focusing on the micro-motion states of rolling elements in spall fault bearings and proposes an improved matching pursuit algorithm for Quantitative Diagnosis with a high accuracy of atom selection and calculation efficiency. The generation mechanism of the vibration response signal is explained by analyzing the micro-motion status when rolling elements passing through the spall. A concatenation dictionary composed of an impact dictionary as the higher level and step dictionary as the lower level is constructed based on the acceleration variation analysis of the rolling elements. The information output by the higher-level dictionary is used as the input information for the lower-level dictionary to extract the fault features. Only one iteration on the higher-level dictionary is necessary to extract the correct impact atoms, with all subsequent iterative steps assigned to the lower-level dictionary. The advantage is that the influence of high-energy impact components on the extraction of step atoms can be removed. Thereafter, the optimized algorithm based on the concatenation dictionary is applied to the analysis of simulation and experimental signals. The comparative analysis demonstrates that the effective Quantitative Diagnosis is obtained, while the diagnostic precision and calculation efficiency are improved.
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fault severity classification and size estimation for ball bearings based on vibration mechanism
IEEE Access, 2019Co-Authors: Lingli Cui, Zhi Jin, Jinfeng Huang, Huaqing WangAbstract:Severity identification and size estimation is a crucial part of the Quantitative Diagnosis for ball bearing faults. In this paper, novel fault severity classification rules and the size estimation model based on vibration mechanism for ball bearings are proposed for more accurate estimation of the fault size. A nonlinear dynamic model, with geometric properties and deformation of the ball considered, is established to analyze the vibration characteristics of ball bearing with outer race fault. It turns out that there are different features in vibration responses with different fault sizes, and then the fault severity is classified with vibration features. Based on the vibration mechanism analysis, functional relations and mathematical expressions between the vibration characteristics and fault sizes are inferred to realize the Quantitative Diagnosis of faulty bearings. The experiments are performed to verify the effectiveness of the proposed method of fault severity classification and size estimation. Deep groove ball bearings designated as 6308, with seeded square-shaped surface defects of different sizes, are chosen for the experiments. The results show that the proposed method can accurately estimate the fault sizes within the acceptable error range.
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Quantitative and localization Diagnosis of a defective ball bearing based on vertical horizontal synchronization signal analysis
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Lingli Cui, Jinfeng Huang, Feibin ZhangAbstract:A novel method is proposed for Quantitative and localization Diagnosis of a bearing outer ring defect in this paper. This method aims to distinguish these defects with different angular positions and different sizes based on the natural multiples of the ball angular spacing. Defects that differ in size by natural multiples of the ball angular spacing will have the same time interval, which may lead to misDiagnosis. Distinguishing such defects accurately is the goal for some industries. Therefore, the synchronized signal in the vertical and horizontal directions of the bearing systems with different angular positions and different size defects are Quantitatively analyzed based on the presented five indices to explore the mechanism and method of distinguishing these defects. The simulation and experimental results show that the vertical–horizontal synchronized root mean square (VHSRMS) index can distinguish such defects effectively, and the defect angle position can be diagnosed using the VHSRMS–1 . More importantly, the VHS analysis method expands the location of the outer ring defect to 265–275° in Quantitative Diagnosis and realizes the localization Diagnosis of the defect angle position. The research results provide a new approach and method for Quantitative and localization Diagnosis of a defective bearing.
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multi scale morphology analysis of acoustic emission signal and Quantitative Diagnosis for bearing fault
Acta Mechanica Sinica, 2016Co-Authors: Wenjing Wang, Lingli Cui, Daoyun ChenAbstract:Monitoring of potential bearing faults in operation is of critical importance to safe operation of high speed trains. One of the major challenges is how to differentiate relevant signals to operational conditions of bearings from noises emitted from the surrounding environment. In this work, we report a procedure for analyzing acoustic emission signals collected from rolling bearings for Diagnosis of bearing health conditions by examining their morphological pattern spectrum (MPS) through a multi-scale morphology analysis procedure. The results show that acoustic emission signals resulted from a given type of bearing faults share rather similar MPS curves. Further examinations in terms of sample entropy and Lempel-Ziv complexity of MPS curves suggest that these two parameters can be utilized to determine damage modes.
Francois Nosten - One of the best experts on this subject based on the ideXlab platform.
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validation of the Quantitative point of care carestart biosensor for assessment of g6pd activity in venous blood
PLOS ONE, 2018Co-Authors: Germana Bancone, Gornpan Gornsawun, Pen Porn, Pooja Bansil, Gonzalo J Domingo, Francois NostenAbstract:Introduction Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in the human population affecting an estimated 8% of the world population, especially those living in areas of past and present malaria endemicity. Decreased G6PD enzymatic activity is associated with drug-induced hemolysis and increased risk of severe neonatal hyperbilirubinemia leading to brain damage. The G6PD gene is on the X chromosome therefore mutations cause enzymatic deficiency in hemizygote males and homozygote females while the majority of heterozygous females have an intermediate activity (between 30–80% of normal) with a large distribution into the range of deficiency and normality. Current G6PD qualitative tests are unable to diagnose G6PD intermediate activities which could hinder wide use of 8-aminoquinolines for Plasmodium vivax elimination. The aim of the study was to assess the diagnostic performances of the new Carestart G6PD Quantitative biosensor. Methods A total of 150 samples of venous blood with G6PD deficient, intermediate and normal phenotypes were collected among healthy volunteers living along the north-western Thailand-Myanmar border. Samples were analyzed by complete blood count, by gold standard spectrophotometric assay using Trinity kits and by the latest model of Carestart G6PD biosensor which analyzes both G6PD and hemoglobin. Results Bland-Altman comparison of the CareStart normalized G6PD values to that of the gold standard assay showed a strong bias in values resulting in poor area under-the-curve values for both 30% and 80% thresholds. Performing a receiver operator curve identified threshold values for the CareStart product equivalent to the 30% and 80% gold standard values with good sensitivity and specificity values, 100% and 92% (for 30% G6PD activity) and 92% and 94% (for 80% activity) respectively. Conclusion The Carestart G6PD biosensor represents a significant improvement for Quantitative Diagnosis of G6PD deficiency over previous versions. Further improvements and validation studies are required to assess its utility for informing radical cure decisions in malaria endemic settings.
Yoshiro Koiwa - One of the best experts on this subject based on the ideXlab platform.
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real time velocimetry for evaluation of change in thickness of arterial wall
Ultrasonics, 2000Co-Authors: Hiroshi Kanai, Yoshiro KoiwaAbstract:We previously developed a new method, namely, the phased tracking method, for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. By this method, the local change in wall thickness during one heartbeat can be determined. We have now developed a real-time system for measuring change in thickness of the myocardium and arterial wall. In this system, four high-speed digital signal processing (DSP) chips are employed for obtaining the initially developed method in real time. The tracking results for both sides of the wall are superimposed on the M (motion)-mode image in the workstation, and the thickness changes of the arterial wall are displayed in real time. Using this system, reported herein, velocity signals of the arterial wall with amplitudes less than several micrometers can be successfully detected in real time with sufficient reproducibility. The elasticity of the arterial wall is evaluated by referring to the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the dose of nitroglycerine (NTG) is evaluated for a young healthy subject and a young smoker. This new real-time system offers potential for Quantitative Diagnosis of early-stage atherosclerosis by the transient evaluation of the rapid response of the cardiovascular system to physiological stress.
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Real-time measurements of local myocardium motion and arterial wall thickening
IEEE transactions on ultrasonics ferroelectrics and frequency control, 1999Co-Authors: Hiroshi Kanai, Yoshiro Koiwa, Jianping ZhangAbstract:We have already developed a new method, namely, the phased tracking method, to track the movement of the heart wall and arterial wall accurately based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. This method has been realized by an off-line measurement system, which cannot be applied to transient evaluation of rapid response of the cardiovascular system to physiological stress. In this paper, therefore, a real-time system to measure change in the thickness of the myocardium and the arterial wall is presented. In this system, an analytic signal from standard ultrasonic diagnostic equipment is analogue-to-digital (A/D) converted at a sampling frequency of 1 MHz. By pipelining and parallel processing using four high-speed digital signal processing (DSP) chips, the method described is realized in real time. The tracking results for both sides of the heart and/or arterial wall are superimposed on the M (motion)-mode image in the work station (WS), and the thickness changes of the heart and/or arterial wall are also displayed and digital-to-analogue (D/A) converted in real time. From the regional change in thickness of the heart wall, spatial distribution of myocardial motility and contractility can be evaluated. For the arterial wall, its local elasticity can be evaluated by referring to the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the dose of the nitroglycerine (NTG) is evaluated. This new real-time system offers potential for Quantitative Diagnosis of myocardial motility, early stage atherosclerosis, and the transient evaluation of the rapid response of the cardiovascular system to physiological stress.
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realtime velocimetry for evaluation of change in thickness of myocardium and arterial wall
Internaltional Ultrasonics Symposium, 1998Co-Authors: Hiroshi Kanai, Yoshiro Koiwa, Noriyoshi Chubachi, Motonao TanakaAbstract:The authors have already developed a new method for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. By pipelining and parallel processing using four high-speed digital signal processing (DSP) chips, the above developed method is realized in real time. By this system, velocity signals of the heart/arterial wall with small amplitudes less than several micrometers on the motion resulting from a heartbeat with large amplitude of several millimeters, can be successfully detected in real time. From the regional change in thickness of the heart wall, spatial distribution of myocardial motility and contractility can be evaluated. For the arterial wall, its elasticity can be evaluated by referring to the blood pressure. This new real-time system offers potential for Quantitative Diagnosis of myocardial motility and early-stage atherosclerosis.
Germana Bancone - One of the best experts on this subject based on the ideXlab platform.
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validation of the Quantitative point of care carestart biosensor for assessment of g6pd activity in venous blood
PLOS ONE, 2018Co-Authors: Germana Bancone, Gornpan Gornsawun, Pen Porn, Pooja Bansil, Gonzalo J Domingo, Francois NostenAbstract:Introduction Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in the human population affecting an estimated 8% of the world population, especially those living in areas of past and present malaria endemicity. Decreased G6PD enzymatic activity is associated with drug-induced hemolysis and increased risk of severe neonatal hyperbilirubinemia leading to brain damage. The G6PD gene is on the X chromosome therefore mutations cause enzymatic deficiency in hemizygote males and homozygote females while the majority of heterozygous females have an intermediate activity (between 30–80% of normal) with a large distribution into the range of deficiency and normality. Current G6PD qualitative tests are unable to diagnose G6PD intermediate activities which could hinder wide use of 8-aminoquinolines for Plasmodium vivax elimination. The aim of the study was to assess the diagnostic performances of the new Carestart G6PD Quantitative biosensor. Methods A total of 150 samples of venous blood with G6PD deficient, intermediate and normal phenotypes were collected among healthy volunteers living along the north-western Thailand-Myanmar border. Samples were analyzed by complete blood count, by gold standard spectrophotometric assay using Trinity kits and by the latest model of Carestart G6PD biosensor which analyzes both G6PD and hemoglobin. Results Bland-Altman comparison of the CareStart normalized G6PD values to that of the gold standard assay showed a strong bias in values resulting in poor area under-the-curve values for both 30% and 80% thresholds. Performing a receiver operator curve identified threshold values for the CareStart product equivalent to the 30% and 80% gold standard values with good sensitivity and specificity values, 100% and 92% (for 30% G6PD activity) and 92% and 94% (for 80% activity) respectively. Conclusion The Carestart G6PD biosensor represents a significant improvement for Quantitative Diagnosis of G6PD deficiency over previous versions. Further improvements and validation studies are required to assess its utility for informing radical cure decisions in malaria endemic settings.
Hiroyuki Hachiya - One of the best experts on this subject based on the ideXlab platform.
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analysis of fluctuation for pixel pair distance in co occurrence matrix applied to ultrasonic images for Diagnosis of liver fibrosis
Journal of Medical Ultrasonics, 2017Co-Authors: Hiroshi Isono, Tadashi Yamaguchi, Shinnosuke Hirata, Hiroyuki HachiyaAbstract:Purpose Chronic liver disease requires careful follow-up during long-term treatment, and development of a Quantitative Diagnosis method for liver fibrosis based on an ultrasonic imaging system is highly desired.
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analysis of fluctuation for pixel pair distance in co occurrence matrix applied to ultrasonic images for Diagnosis of liver fibrosis
Journal of Medical Ultrasonics, 2017Co-Authors: Hiroshi Isono, Tadashi Yamaguchi, Shinnosuke Hirata, Hiroyuki HachiyaAbstract:Chronic liver disease requires careful follow-up during long-term treatment, and development of a Quantitative Diagnosis method for liver fibrosis based on an ultrasonic imaging system is highly desired. Texture analysis using a co-occurrence matrix was applied to both clinical and simulated ultrasonic images of fibrotic livers. A sequence of matrices was generated for pixel-pair distance, r, and texture feature contrast was chosen to examine the response to r in combination with statistical analysis of echo amplitude distribution using a multi-Rayleigh model. The contrast converged with a larger value and fluctuated more significantly in response to r as fibrosis progressed in both the clinical and simulated ultrasonic images. The convergent value rapidly increased at the early stage of fibrosis, and the fluctuation became larger at the advanced stage of fibrosis. Analysis using simulated ultrasonic images with a known fibrous tissue structure theoretically clarified the relationship between contrast behavior and fibrosis progression. It was revealed that contrast convergent value and contrast fluctuation provided information on the fibrous tissue structure, and they are expected to be used for Quantitative Diagnosis of the degree of liver fibrosis.
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quantification of the scatterer distributions for liver fibrosis using modified q q probability plot
Internaltional Ultrasonics Symposium, 2014Co-Authors: Mikito Ito, Hiroyuki Hachiya, Kenji Yoshida, Jonathan Mamou, Tadashi YamaguchiAbstract:To realize a Quantitative Diagnosis method of liver fibrosis, we have been developing a modeling method for the probability density function of the echo amplitude. In our previous study, we proposed a multi-Rayleigh model with two or three Rayleigh distributions, which is considered as a heterogeneous medium consisting of normal and different tissue, and constructed the evaluation method using modified quantile-quantile probability plot (Q-Q plot). In this study, we examined a multi-Rayleigh model and generalized Nakagami model which is general technique, corresponding to the distribution of the echo amplitude from homogeneous and heterogeneous medium. In clinical data of liver fibrosis, we showed validity of proposed model.
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Quantitative evaluation of liver fibrosis using multi rayleigh model with hypoechoic component
Japanese Journal of Applied Physics, 2013Co-Authors: Tatsuya Higuchi, Shinnosuke Hirata, Tadashi Yamaguchi, Hiroyuki HachiyaAbstract:To realize a Quantitative Diagnosis method of liver fibrosis, we have been developing a modeling method for the probability density function of the echo amplitude. In our previous model, the approximation accuracy is insufficient in regions with hypoechoic tissue such as a nodule or a blood vessel. In this study, we examined a multi-Rayleigh model with three Rayleigh distributions, corresponding to the distribution of the echo amplitude from hypoechoic, normal, and fibrous tissue. We showed Quantitatively that the proposed model can model the amplitude distribution of liver fibrosis echo data with hypoechoic tissue adequately using Kullback–Leibler (KL) divergence, which is an index of the difference between two probability distributions. We also found that fibrous indices can be estimated stably using the proposed model even if hypoechoic tissue is included in the region of interest. We conclude that the multi-Rayleigh model with three components can be used to evaluate the progress of liver fibrosis Quantitatively.
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estimation of characteristics of echo envelope using rf echo signal from the liver
Japanese Journal of Applied Physics, 2001Co-Authors: Tadashi Yamaguchi, Hiroyuki Hachiya, Kazuki Ikeda, Naohisa Kamiyama, Norifumi MoriyasuAbstract:To realize Quantitative Diagnosis of liver cirrhosis, we have been analyzing the probability density function (PDF) of echo amplitude using B-mode images. However, the B-mode image is affected by the various signal and image processing techniques used in the Diagnosis equipment, so a detailed and Quantitative analysis is very difficult. In this paper, we analyze the PDF of echo amplitude using RF echo signal and B-mode images of normal and cirrhotic livers, and compare both results to examine the validity of the RF echo signal.
