Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 7 of 7
Full-Text Articles in Engineering
Intelligent Identification Of Childhood Musical Murmurs, Yuerong Chen, Shengyong Wang, Chia-Hsuan Shen, Fred Choy
Intelligent Identification Of Childhood Musical Murmurs, Yuerong Chen, Shengyong Wang, Chia-Hsuan Shen, Fred Choy
Fred K. Choy
Heart murmurs are often the first signs of heart valvular disorders. However, most heart murmurs detected in children are innocent musical murmurs (also called Still's murmurs), which should be distinguished from other murmur types that are mostly pathological, such as regurgitant, obstructive, and flow murmurs. In order to reduce both unnecessary healthcare expenditures and parental anxiety, this study aims to develop algorithms for intelligently identifying musical murmurs in children. Discrete wavelet transform was applied to phonocardiographic signals to extract features. Singular value decomposition was applied on the matrix derived from continuous wavelet transform to extract extra features. The sequential forward …
Matrix Decomposition Based Feature Extraction For Murmur Classification, Yuerong Chen, Shengyong Wang, Chia-Hsuan Shen, Fred Choy
Matrix Decomposition Based Feature Extraction For Murmur Classification, Yuerong Chen, Shengyong Wang, Chia-Hsuan Shen, Fred Choy
Fred K. Choy
Heart murmurs often indicate heart valvular disorders. However, not all heart murmurs are organic. For example, musical murmurs detected in children are mostly innocent. Because of the challenges of mastering auscultation skills and reducing healthcare expenses, this study aims to discover new features for distinguishing innocent murmurs from organic murmurs, with the ultimate objective of designing an intelligent diagnostic system that could be used at home. Phonocardiographic signals that were recorded in an auscultation training CD were used for analysis. Instead of the discrete wavelet transform that has been used often in previous work, a continuous wavelet transform was applied …
Analytical And Numerical Study Of A Misaligned Cavitating Hydrodynamic Cryogenic Journal Bearing, Fred Choy, Minel Braun, Y. Hu
Analytical And Numerical Study Of A Misaligned Cavitating Hydrodynamic Cryogenic Journal Bearing, Fred Choy, Minel Braun, Y. Hu
Fred K. Choy
High speed hydrodynamic/hydrostatic journal bearings have been widely used in various types of rotating machinery. In space applications, the use of cryogenic fluids as working lubricants has become significant. The primary goal of this paper is to model the nonlinearities that occur in a cryogenic, liquid oxygen (LO2) hydrodynamic journal bearing. They will be examined through bearing-fluid-film pressure distribution and linear and non-linear bearing stiffness and damping characteristics. The numerical model that couples a variable property Reynolds' equation with the dynamics of the rotor is solved by means of a finite difference solution technique. The procedure involves an iterative scheme …
Oil Debris And Viscosity Monitoring Using Ultrasonic And Capacitance/Inductance Measurements, Matthew Appleby, Fred Choy, Li Du, Jiang Zhe
Oil Debris And Viscosity Monitoring Using Ultrasonic And Capacitance/Inductance Measurements, Matthew Appleby, Fred Choy, Li Du, Jiang Zhe
Fred K. Choy
No abstract provided.
Two-Dimensional Dynamic Simulation Of A Continuous Foil Bearing, Minel Braun, Fred Choy, M. Dzodzo, J. Hsu
Two-Dimensional Dynamic Simulation Of A Continuous Foil Bearing, Minel Braun, Fred Choy, M. Dzodzo, J. Hsu
Fred K. Choy
The objective of this paper is to present an integrated procedure which will analyse the dynamics of a foil bearing on elastic supports. A complete time-dependent Navier-Stokes formulation is used to solve for the interaction between the hydrodynamic effects of the fluid lubricant, the motion of the journal, and the deformable foil boundary. The elastic deformation of the foil and its supports are simulated by a finite element model. The steady state, the quasi-transient and the full transient dynamics of the foil-fluid-journal interaction are examined. For the steady state simulation, for a particular journal position, the fluid lubricant pressures are …
A Modular Approach To Computer-Aided Auscultation: Analysis And Parametric Characterization Of Murmur Acoustic Qualities, Chia-Hsuan Shen, Fred Choy, Yuerong Chen, Shengyong Wang
A Modular Approach To Computer-Aided Auscultation: Analysis And Parametric Characterization Of Murmur Acoustic Qualities, Chia-Hsuan Shen, Fred Choy, Yuerong Chen, Shengyong Wang
Fred K. Choy
In the present work, a modularized approach to computer-aided auscultation based on the traditional cardiac auscultation of murmur is proposed. Under such an approach, the present paper concerns the task of evaluating murmur acoustic quality character. The murmurs were analyzed in their time-series representation, frequency representation as well as time-frequency representation, allowing extraction of interpretable features based on their signal structural and spectral characters. The features were evaluated using scatter plots, receiver operating characteristic curves (ROC), and numerical experiments using a KNN classifier. The possible physiological and hemodynamical associations with the feature set are made. The implication and advantage of …
Design Considerations Towards The Construction Of Hybrid Floating Brush Seal (Hfbs), S. Lattime, Minel Braun, Fred Choy
Design Considerations Towards The Construction Of Hybrid Floating Brush Seal (Hfbs), S. Lattime, Minel Braun, Fred Choy
Fred K. Choy
The hybrid floating brush seal (HFBS) represents an advance in brush seal technology by combining brush seal and film riding face seal technologies to create a hybrid seal that allows both axial and radial excursions of the sealed shaft without damage to seal integrity. At the same time, it eliminates interface surface speeds between the rotor and the brush bristles. This accomplishment is possible because the brush seal, which forms the primary seal, rotates with the shaft, while floating against a hydrodynamic face seal surface, which makes up the secondary seal. The present paper presents continuation work (Int J of …