• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.143-146
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• 1996

An adaptive digital filtering of the electroencophalogram(EEG) is a successful way of suppressing mains interference, but it affects some of the frequency components of the signal, an artifact which not be acceptable in some cases of automatic EEG processing. The types of electrical artifact seen on EEG records is described. Those are the EOG and the PVC roller pump noise. And we study the method for cancelling these artifacts. The method does not need the reference channel, and are obtained by cascading the linear predictor and the noise canceller. The simulation results illustrate the performances of the presented method in terms of the capability of interferences suppression.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.391-396
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• 2013

Psycho-acoustic experiments were carried out to know the inhabitant's response on floor impact noises due to floor structure types. The response values for tapping machine, bang machine and impact ball were 4.4~6.06. And children walking and adult walking were 1.67~2.97. Using 11 scale response tests, children and adult walking was not irritate to dwellers and children running was disturbing.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.662-665
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• 2005

In this study acoustical characteristics of system air conditioner in different ceiling systems was investigated in anechoic and real conditions. Same Types of air conditioners were installed in two different rooms. The results showed that motor's tonal component was emphasized at near fart of air blast blower in the exposed type while fan's harmonic component is emphasized rather in the enclosed type. This confirms tile result of acoustical intensity mapping which showed that Intensity level of 125Hz octave band increased in the exposed type while there was no noticeable difference at the frequency band in the enclosed type.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.445-450
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• 2004

Recently, the interest on the comfortable dwelling environment is increasing and the effort to solve the problem of exterior noise was tried. The propose of this study is to suggest the design of balcony window in apartment and to evaluate the sound insulation of it. So, we designed five types of balcony window which were considered not only sound insulation but ventilation. The sound reduction index of window was evaluated by the measurement in mock-up room. The results showed that case 2 improved about 6dB in the weighted apparent sound reduction index than case 1, and case 3 reduced about 39% in construction cost than case 4.

• 대한원격탐사학회지
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• 제19권5호
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• pp.403-409
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• 2003

Since SPOT4 satellite contained VEGETATION 1 sensor launched, the noise in VEGETATION data was occasionally arisen a difficulty for the data traitement. Blind line noise types were studied in VEGETATION-l short wave infrared channel(SWIR). In order to provide a precis product, the procedure for removing this noise is strongly recommended. In the case that the blind values are clearly distinguished from contamination-free values a simple threshold method was applied, while a changeable threshold method was used for the blind value mixed with contamination-free values. New algorithm presented in this study is consists of two method for each type of SWIR blind. After removing blind line, there were again some residual pixels of blind, because the threshold is not determinated sufficiently low. Lower threshold could remove the blind line as well as the contamination-free pixels. Nevertheless, the results showed a good qualitative improvement as compared with other algorithm.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.44-50
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• 2001

현재까지 운전중인 변압기에 전기적인 부분방전 측정기법을 적용하기 위한 가장 큰 문제점은 외부 코로나 노이즈를 제거하는 것이다. 본 논문에서는 외부 코로나 노이즈를 제거하고 변압기 내부의 결함에 의한 부분방전 신호만을 측정하는 기법에 대하여 연구하였다. 현장에서 운전중인 변압기에서의 부분방전과 코로나 노이즈의 발생 형태를 모의하기 위하여 모의 변압기 내에 침-평판 전극을 이용하여 변압기 내부 부분방전을 발생시켰으며, 동시에 변압기 외부의 공기 중에 봉-구 전극을 이용하여 외부 코로나 노이즈를 발생시켰다. 변압기 접지선에 설치한 로고우스키 코일에는 변압기의 내부 결함에 의해 발생되는 부분방전 신호와 외부 코로나 노이즈가 동시에 측정되었다. 변압기 외부에 안테나 센서를 이용하여 외부 코로나 노이즈를 별도로 측정하여, 코로우스키 코일에서 측정된 신호에서 코로나 노이즈를 제거한 결과, 변압기 내부의 부분방전에 의한 신호만을 효과적으로 검출할 수 있었다.

• 한국정보통신학회논문지
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• 제21권8호
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• pp.1540-1546
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• 2017

디지털 영상 처리는 군사, 의료, 영상인식 시스템, 로봇, 산업 등의 여러 분야에서 다양하게 활용되고 있다. 그러나 디지털 영상은 영상을 획득, 전송하는 과정에서 여러 외부 원인에 의해 발생된다. 일반적으로 영상에 중첩되는 잡음에는 발생 원인과 형태에 따라 다양하며, AWGN 및 임펄스 잡음이 대표적이다. 영상처리에서 잡음 제거는 영상 분할, 영상 인식, 특징 추출 등의 전처리 과정에서 필수적이다. 따라서 본 논문은 영상에 첨가된 잡음을 효과적으로 제거하기 위해, 캐니 에지를 이용하여 비에지 영역과 에지 영역을 구분하여 각 영역에 따라 필터를 다르게 적용하여 처리하는 알고리즘을 제안하였다. 그리고 제안한 알고리즘의 우수성을 입증하기 위해, 확대 영상, 에지 영상 및 PSNR(peak signal to noise ratio)을 이용하여 기존의 방법들과 성능을 비교하였다.

• 한국항행학회논문지
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• 제24권6호
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• pp.587-592
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• 2020

사물 인터넷 패러다임에 의해 가능해진 거대한 정보 교환은 즉시 사용 가능한 인프라로 전선을 이용할 가능성이 높아지고 있다. 사전에 설치된 배선 네트워크 인프라를 사용하는 이점은 전력선 통신을 광대역 통신을 위한 경쟁력있는 기술로 만들었다. 따라서 기존의 전력선 통신 채널을 고속 데이터 전송 및 인터넷 서비스를 위한 효과적인 수단으로 사용하는 것에 대한 관심이 높아지고 있다. 전력선 통신 시스템에 영향을 미치는 주요 잡음의 유형 중 하나는 임펄스 잡음이며 본 논문은 임펄스 잡음이 OFDM-QPSK 시스템의 성능에 미치는 영향을 해석하였다. 임펄스 잡음의 성능 분석을 위하여 3가지 환경에서 측정된 데이터를 사용하였다. 분석을 통해 OFDM-QPSK 시스템이 대부분의 임펄스 잡음 사례에서 QPSK 시스템보다 우수한 것으로 나타났다. 또한 RS 부호화된 OFDM-QPSK 시스템은 3 가지 경우의 임펄스 잡음 환경에서 우수한 BER 성능을 달성할 수 있었다.

• 한국의학물리학회지:의학물리
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• 제32권4호
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• pp.92-98
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• 2021

Purpose: This study automatically discriminates homogeneous and structure edge regions on computed tomography (CT) images, and it evaluates the noise level and edge preservation ratio (EPR) according to the different types of iterative reconstruction (IR). Methods: The dataset consisted of CT scans of 10 patients reconstructed with filtered back projection (FBP), statistical IR (iDose⁴), and iterative model-based reconstruction (IMR). Using the 10th and 85th percentiles of the structure coherence feature, homogeneous and structure edge regions were localized. The noise level was estimated using the averages of the standard deviations for five regions of interests (ROIs), and the EPR was calculated as the ratio of standard deviations between homogeneous and structural edge regions on subtraction CT between the FBP and IR. Results: The noise levels were 20.86±1.77 Hounsfield unit (HU), 13.50±1.14 HU, and 7.70±0.46 HU for FBP, iDose⁴, and IMR, respectively, which indicates that iDose⁴ and IMR could achieve noise reductions of approximately 35.17% and 62.97%, respectively. The EPR had values of 1.14±0.48 and 1.22±0.51 for iDose⁴ and IMR, respectively. Conclusions: The iDose⁴ and IMR algorithms can effectively reduce noise levels while maintaining the anatomical structure. This study suggested automated evaluation measurements of noise levels and EPRs, which are important aspects in CT image quality with patients' cases of FBP, iDose⁴, and IMR. We expect that the inclusion of other important image quality indices with a greater number of patients' cases will enable the establishment of integrated platforms for monitoring both CT image quality and radiation dose.

• 한국주거학회논문집
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• 제3권2호
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• pp.75-88
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• 1992

The purpose of this study is to analyze the relations between the conditions of the flaws and the types of damage according to the characteristics of housing, and then to provide with some basic data for the construction of houses of good quality. The effective analytic data for this research are 558 of all 700 questionnaires gathered through distribution collection and personal interviews conducted from June 22, 1992 Through to July 6, towards the first occupants in apartment houses, tenement houses, multidetached houses, multifamily houses and detached houses that last 10 years after construction, located in Seoul and Kyungki-Do. Our major findings are as under:1) Our data reveal that the ratio of flaw occurrence by general type breaks down into noise 53.7%, crack 39.3%, dew condensation 36.9%, windows and doors 36.6%, structure and frame 35.3%, built-in materials 33.3%, the inferiority of equipments/facilities 29.0%, ill drainage 22.0%, and the leakage of water 19.3% average number of flaw occurrence, multi detached house is the highest as 13.7, apartment house 10.5, tenement house 10.5, detached house 10.51 and multifamily house 8.7.3) As regards the degree of flaw occurrence, the flaw of noise is as serious in the degree of occurence as it is high in the ratio of occurrence. Particularly, the following contrastive phenomena are found: multidetached house is normal (2.0) in the degree of occurrence but it is high in the ratio of occurrence: while multifamily house is 2.9 in the degree of occurrence but it is low in the ratio of occurrence.4) In view of the relations between the types of flaws and those of damage, the flaw type which significantly influences on the injury of spirit and health is built-in materials; the flaw types that have considerable effect on the damage of house and home life are the inferiority of equipments/facilities, due condensation, and inferior windows and doors; and the flaw types that have a bad influence over the reliance on the constructors are the inferiority of equipments/facilities, due condensation and built-in materials.