• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.2
• /
• pp.335-341
• /
• 2009

Analysis of the partial discharge signal, a technique to diagnose the stator winding insulation is a key function for the diagnosis of high voltage rotating machines and requires high precision. To satisfy this requirement, various denoising techniques such as filtering and differential methods were proposed. However, these techniques can not eliminate a adjacent induction noise that decreases reliability of the diagnosis. A simple novel denoising algorithm, therefore, is proposed for removing the adjacent induction noise in this paper. The algorithm shows good performance in the real partial discharge signals measured by 13kV class capacitive couplers installed at hydro-generator in Dae-cheong Dam.

• Journal of information and communication convergence engineering
• /
• v.5 no.1
• /
• pp.1-6
• /
• 2007

In the process of the acquisition, storage, transmission of signals, noises are generated by various causes and the degradation phenomenon by noises tends to generate serious errors for the signal with information. So, in order to analyze and remove these noises, studies on numerous mathematical methods such as the Fourier transform have been implemented. And recently there have been many ongoing wavelet-based denoising algorithms representing excellent characteristics in time-frequency localization and multiresolution analysis, but the method to remove additive white Gaussian noise (AWGN) and the impulse noise simultaneously was not given. So, to reconstruct the corrupted signal by noises, in this paper a novel wavelet-based denoising algorithm was proposed and using signal-to-noise ratio (SNR) this method was compared to conventional methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.946-949
• /
• 2005

In this paper, influence factors on dynamic properties of floor impact noise insulation materials are suggested. For this purpose measurements on the dynamic stiffness and the loss factor of resilient materials are carried out by Korea standard (KS F 2868) according to the change of density, thickness, design pattern, and composition of materials. As a result the values of dynamic stiffness was decreased at high density and thick thickness, and that of loss factor was increased at low density. For dynamic properties, the pattern of lattice and waffle type material is better than that of plat type, and the mixed composition of materials is better than the composition of double layer materials at same thickness.

• Journal of Information Processing Systems
• /
• v.17 no.4
• /
• pp.737-753
• /
• 2021

As the demand for high-quality rendering for mixed reality, videogame, and simulation has increased, global illumination has been actively researched. Monte Carlo path tracing can realize global illumination and produce photorealistic scenes that include critical effects such as color bleeding, caustics, multiple light, and shadows. If the sampling rate is insufficient, however, the rendered results have a large amount of noise. The most successful approach to eliminating or reducing Monte Carlo noise uses a feature-based filter. It exploits the scene characteristics such as a position within a world coordinate and a shading normal. In general, the techniques are based on the denoised pixel or sample and are computationally expensive. However, the main challenge for all of them is to find the appropriate weights for every feature while preserving the details of the scene. In this paper, we compare the recent algorithms for removing Monte Carlo noise in terms of their performance and quality. We also describe their advantages and disadvantages. As far as we know, this study is the first in the world to compare the artificial intelligence-based denoising methods for Monte Carlo rendering.

• KIEAE Journal
• /
• v.9 no.1
• /
• pp.99-106
• /
• 2009

This study aims to survey the acoustical environment in the region around airport where there are various transportation noises such as aircraft noise, railway noise and traffic noise, and to analyze the subjective response on the noise to the people who live in house or work in office nearby airport. Measurement and subjective response evaluation were carried out at the same time and outdoor noise level was measured all day long to calculate one day results such as average Leq or one day WECPNL etc. The results showed that the military aircraft produces very high level comparing with commercial aircraft, for instance the sound level of commercial outdoor was lower than that of military aircraft indoor. Double and triple window were more effective for controlling the noise than single window, which showed the possibility of sound insulation treatment by installing windows having higher sound insulation performance. Finally the subjective response was resulted that the most annoying noise is from aircraft and counterplan they hope is 'airport moving out'. Leq 65 dB(A), the criteria value of sound insulation treatment, was corresponding to the subjective response of median annoyance '4' out of 7th scale.

• Journal of the Korean Home Economics Association
• /
• v.42 no.6
• /
• pp.1-12
• /
• 2004

This study investigates residents' living satisfaction with high-rise, mixed-use apartments built in the structures of reinforced concrete construction(RC) and with steel framed, reinforced concrete construction(SRC). The following study results were obtained: 1) Residents expressed below average satisfaction (below 3.0) with the common-area landscape and environmentally-friendly factors, children's playground and its facilities, community service for residents' by the management offices and utility plan. 2) According to the satisfaction of sound environment, residents of the SRC group expressed above average satisfaction. It can be concluded that noise problems around the residential area of the SRC group was well solved in this study. However, the residents of the SRC group expressed low satisfaction with the freshness of indoor air, humidity, and smell in the living quarters. 3) High-rise, mixed-use apartments should accommodate a familial life cycle, be designed as an environmentally friendly resting place in harmony with city life, and provide various communal programs for residents.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2003.11a
• /
• pp.145-149
• /
• 2003

This study is to investigate residents' living satisfaction with high-rise mixed-use apartment complexes built in the structures of the reinforced concrete constructing and the steel framed reinforced concrete construction. The results of this study were obtained as follows: 1. Residents expressed below average satisfaction (below 3.0) with the common-area landscape and environmentally-friendly factors, children's playground and its facilities, community service for residents' by the management offices and the plan of utility. 2.According to the satisfaction of sound environment, residents of SRC group expressed above average satisfaction; it can be concluded that problems of causing noise around the residential area of the SRC and S groups were well solved in this study. However, satisfaction with the freshness of indoor air, humidity, and smell in the living quarters was rated low by the residents of SRC group. 3. High-rise mixed-use apartment complexes should accomodate families's life cycle, design an environmentally-friendly resting place in harmony with city life, and provide various communal programs for residents.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.11
• /
• pp.13-22
• /
• 2010

This paper proposed the dual-loops multiphase DLL based mixed VCO/VCDL for a high frequency phase noise suppression of the input clock and the multiple frequencies generation with a precise duty cycle. In the proposed architecture, the dual-loops DLL uses the dual input differential buffer based nMOS source-coupled pairs at the input stage of the mixed VCO/VCDL. This can easily convert the input and output phase transfer of the conventional DLL with bypass pass filter characteristic to the input and output phase transfer of PLL with low pass filter characteristic for the high frequency input phase noise suppression. Also, the proposed DLL can correct the duty-cycle error of multiple frequencies by using only the duty-cycle correction circuits and the phase tracking loop without additional correction controlled loop. At the simulation result with $0.18{\mu}m$ CMOS technology, the output phase noise of the proposed DLL is improved under -13dB for 1GHz input clock with 800MHz input phase noise. Also, at 1GHz operating frequency with 40%~60% duty-cycle error, the duty-cycle error of the multiple frequencies is corrected under $50{\pm}1%$ at 2GHz the input clock.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.240-242
• /
• 2005

It is well known that the PD (Partial Discharge) signals are generated if insulators have some defects such as voids in electrical facility and various PD detection methods are developed for preventing electrical troubles. So, an interest for the PD signals is higher and higher according to the high concern for the defects detection method of the aging electrical facility. When the equipment to detect PD signals installed at site and it works, a lot of noises flow in the equipment from surrounding situation and it will be mixed with original PD waveform. So we can not get the desired PD waveform. Therefore, there are many trial to reject or suppress the noise from the PD signals from long times ago. The greater of them used the hardware such as bridge circuits and frequency filters to suppress the noise. This paper proposed a novel noise rejection method in acquired data from PD detection equipment. The noise has the irregular phase and higher signal level than real PD, and noise decision is performed after inspection of pulse distribution in ${\Phi}$-q-n graph of acquired data from PD detection equipments. By experimental results on high voltage electric equipments, it is shown that proposed method has good performance. It is expected that this noise rejection technology is useful in numeric calculation and trend management of PD level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.793-796
• /
• 2017

Image signal can be damaged by a variety of noises during the signal processing, and multiple studies have been conducted to restore these signals. The representative noises to be added in the image are salt and pepper noise, additive white Gaussian noise(AWGN), and the composite noise which two noises are combined. Therefore, the algorithms were proposed to process with quadratic spline interpolation and median filter in case of salt and pepper noise with the central pixel of the local mask, and to process with weight filter by pixel changes in case of AWGN, upon noise determination to restore the damaged image in the composite noise environment, in this article.