scispace - formally typeset
Search or ask a question
Author

Sang-Kwon Lee

Bio: Sang-Kwon Lee is an academic researcher from Inha University. The author has contributed to research in topics: Sound quality & Noise. The author has an hindex of 18, co-authored 162 publications receiving 1513 citations.


Papers
More filters
Journal ArticleDOI
Sang-Kwon Lee1
TL;DR: In this article, a sound quality index evaluating the quality of these two sounds objectively is therefore required and is developed by using an artificial neural network (ANN) in the present paper, which is successfully applied to the enhancement of the interior sound quality for a developmental passenger car.

98 citations

Journal ArticleDOI
TL;DR: In this paper, the authors identify the characteristics of dispersive acoustic wave through analysis of the cut-off frequency by using the time-frequency method experimentally and BEM theoretically for the development of an experimental tool to analyze the leak signals in steel pipe.
Abstract: A time–frequency technique for locating leaks in buried gas distribution pipes involves the use of the cross-correlation on two measured acoustic signals on either side of a leak. This technique can be problematic for locating leaks in steel pipes, as the acoustic signals in these pipes are generally narrow-band and low frequency. The effectiveness of the time–frequency technique for detecting leaks in steel pipes was investigated experimentally in an earlier study. The object of this paper is to identify the characteristics of this dispersive acoustic wave through analysis of the cut-off frequency by using the time–frequency method experimentally and BEM (boundary element method) theoretically for the development of an experimental tool to analyze the leak signals in steel pipe. The tool is based on experimental work and theoretical formulation of wave propagation in a fluid-filled pipe. This tool uses the time–frequency method to explain some of the features of wave propagation measurements made in gas pipes. Leak noise signals are generally passed through a time–frequency filter for detection of impulse signal related leakage.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the results of experimental investigations carried out to assess wear in spur gears of single stage spur gear box under fatigue test conditions were presented, which considered the lubricant film thickness analysis, wear mechanism studies on gear tooth surfaces, oil degradation analysis using Fourier transform infrared radiation (FTIR) method along with vibration signal analysis.

45 citations

Journal ArticleDOI
TL;DR: In this paper, a modified-filtered-u LMS (MFU-LMS) algorithm is proposed for active noise control in a short acoustic duct of an automobile engine.

45 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A review of the past, recent developments and implementations of the Bouc-Wen model which is used extensively in modeling the hysteresis phenomenon in the dynamically excited nonlinear structures can be found in this paper.
Abstract: Structural systems often show nonlinear behavior under severe excitations generated by natural hazards. In that condition, the restoring force becomes highly nonlinear showing significant hysteresis. The hereditary nature of this nonlinear restoring force indicates that the force cannot be described as a function of the instantaneous displacement and velocity. Accordingly, many hysteretic restoring force models were developed to include the time dependent nature using a set of differential equations. This survey contains a review of the past, recent developments and implementations of the Bouc-Wen model which is used extensively in modeling the hysteresis phenomenon in the dynamically excited nonlinear structures.

602 citations

Journal ArticleDOI
TL;DR: This paper identifies the state-of-the-art in leak detection and localization methods and evaluates the capabilities of these techniques in order to identify the advantages and disadvantages of using each leak detection solution.
Abstract: Gas leaks can cause major incidents resulting in both human injuries and financial losses. To avoid such situations, a considerable amount of effort has been devoted to the development of reliable techniques for detecting gas leakage. As knowing about the existence of a leak is not always enough to launch a corrective action, some of the leak detection techniques were designed to allow the possibility of locating the leak. The main purpose of this paper is to identify the state-of-the-art in leak detection and localization methods. Additionally we evaluate the capabilities of these techniques in order to identify the advantages and disadvantages of using each leak detection solution.

429 citations

Journal ArticleDOI
TL;DR: In this paper, the characteristics of magnetorheological dampers are summarized according to the measured responses under different conditions and the state-of-the-art parametric dynamic modelling, identification and validation techniques for MR dampers were reviewed.
Abstract: Due to the inherent nonlinear nature of magnetorheological (MR) dampers, one of the challenging aspects for developing and utilizing these devices to achieve high performance is the development of models that can accurately describe their unique characteristics. In this review, the characteristics of MR dampers are summarized according to the measured responses under different conditions. On these bases, the considerations and methods of the parametric dynamic modelling for MR dampers are given and the state-of-the-art parametric dynamic modelling, identification and validation techniques for MR dampers are reviewed. In the past two decades, the models for MR dampers have been focused on how to improve the modelling accuracy. Although the force–displacement behaviour is well represented by most of the proposed dynamic models for MR dampers, no simple parametric models with high accuracy for MR dampers can be found. In addition, the parametric dynamic models for MR dampers with on-line updating ability and the inverse parametric models for MR dampers are scarcely explored. Moreover, whether one dynamic model for MR dampers can portray the force–displacement and force–velocity behaviour is not only determined by the dynamic model itself but also determined by the identification method.

408 citations

Journal ArticleDOI
TL;DR: In this article, preparation methods and magnetorheological properties of various magnetic composites with soft magnetic particles and polymers are reviewed, and some industrial applications, such as a MR dampers and a MR polishing, are briefly summarized.
Abstract: As one of the most important field-responsive intelligent and smart soft matter materials, magnetorheological (MR) fluids, consisting of magneto-responsive magnetizable particles suspended in non-magnetic fluids, have drawn a lot of attentions in both academia and industry as their physical and rheological characteristics can be controlled with external magnetic field strength. In this highlight, preparation methods and MR properties of various magnetic composites with soft magnetic particles and polymers are reviewed. In addition, some industrial applications, such as a MR dampers and a MR polishing, are briefly summarized.

397 citations

Journal ArticleDOI
TL;DR: A WT condition monitoring technique that uses the generator output power and rotational speed to derive a fault detection signal and uses a continuous-wavelet-transform-based adaptive filter to track the energy in the prescribed time-varying fault-related frequency bands in the power signal.
Abstract: Cost-effective wind turbine (WT) condition monitoring assumes more importance as turbine sizes increase and they are placed in more remote locations, for example, offshore. Conventional condition monitoring techniques, such as vibration, lubrication oil, and generator current signal analysis, require the deployment of a variety of sensors and computationally intensive analysis techniques. This paper describes a WT condition monitoring technique that uses the generator output power and rotational speed to derive a fault detection signal. The detection algorithm uses a continuous-wavelet-transform-based adaptive filter to track the energy in the prescribed time-varying fault-related frequency bands in the power signal. The central frequency of the filter is controlled by the generator speed, and the filter bandwidth is adapted to the speed fluctuation. Using this technique, fault features can be extracted, with low calculation times, from direct- or indirect-drive fixed- or variable-speed WTs. The proposed technique has been validated experimentally on a WT drive train test rig. A synchronous or induction generator was successively installed on the test rig, and both mechanical and electrical fault like perturbations were successfully detected when applied to the test rig.

350 citations