• 한국환경과학회지
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• 제23권7호
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• pp.1307-1320
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• 2014

A number of problems associated with environmental noises in urban areas have significantly been considered. Specific measurement and estimation of the environmental noise became a primary issue in local governments. Environmental noise monitoring system is required in order to estimate and verify the a city noise map. However, current monitoring positions may not perfectly represent and incorporate many different view points, such as districts of a city, different utilizations of a city by the law, populations, and classifications and traffics of roads. In addition, scientific method to provide specific noise monitoring positions my not be avaliable in current literature. For this reason, the primary objective of this paper is to propose a new method for introducing a number of monitoring positions in the entire city. First, the quality function deployment (QFD) method was utilized to simultaneously represent both districts and utilizations of a city. Second, a new algorithm to find a number of monitoring positions was proposed by compromising many different view points: populations, classifications of roads and areas, and traffics of roads. Finally, the proposed monitoring positions and a sample noise map was provided for verification purposes. Based on these results, the proposed algorithm including the QFD concept may successfully provide specific noise monitoring positions by simultaneously consider may different view points and requirements of a city.

• 기술사
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• 제16권3호
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• pp.41-53
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• 1983

The Dangri Crushed Stone Quarry is located in Dangridong, Busan City, and around the estuary of the Nagdong River. The quarry is considered to be a very promised one in the urban area from the standpoints of the assessment of the aggregate rank, the environmental impacts and the transportation distance. The crushed stones for aggregate of the quarry marks the higher rank in the gravity, the absorption ratio, the abrasion ratio, and the stability in comparison with the JISA 5005. The basement vibrations of the residential section in the vicinity of the quarry, which are arised by the millisecond blasting at the quarry site using the gelatin dynamites less than 39kg in weight, are measured to assess the vibration nuisance. The values of acceleration and the magnitudes are less than eight gals and O on the Richter scale respectively, the vibration nuisance thus can be ignored in such scales of the experiments. The traffic vibrations of the residential section are slightly susceptible. In the experiments, the traffic vibrations appears to be sensibler to the basement than the explosion vibration. The explosion noises in the experiments are not checked not only on the RION Sound Level Meter but also to our ears. The values of traffic noises also are in the safety values of the noise nuisance. The crush dust suspends in the air toward the upper valley in the opposite side of the residential area because of the influences of the sea breeze and the valley wind in the daytime, and the monsoon and the topographic disposition. the dust nuisance thus would not be remained in problem. The quarry is operated in the daytime only. The traffic dust in the residential area will be reduced by the faultless pavement and the careful driving. The elaborate survey on the ridges and peaks surrounded the quarry is recommended to prevent in advance the accidents of the rock slide. Moreover, it is required to make an advisory committee to develop the industry and to save the techniques. The most important matter is the accomodation between the attitude of the enterprising man for the social responsibility to the public nuisance and the cooperative spirit of the inhabitants for the industry.

• 한국소음진동공학회논문집
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• 제17권3호
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• pp.241-248
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• 2007

A study has been conducted to investigate the subjective responses of loudness and annoyance according to the exposed time of urban traffic noise in controlled laboratory environment. To make a closer inspection into psychological response relevant to noise characteristics while varying the time of exposure to noise, the subjects were presented a set of noises with different exposed time and requested to judge spontaneously on a 100-unipolar scale. To be concrete, the subjects were exposed to noises being varied in time from 15 sec up to max. 1,200 sec for the controlled traffic noise sources. So far achieved from laborious tests, it has an importance being on the logarithmic relations of perceived loudness and exposed time, say, it is more increased the perceived loudness in the sorter exposed time than in the longer exposed time. However, the trend is said to be not effective for the case of annoyance. On the other hand, the subjective impressions on relative annoyance of noise is shown to be correlated with the noise characteristics such as loudness (sones), tonality and time with logarithmic scale, the product correlation moment being calculated as $R^{2}=0.99$. The variances to be explained for annoyance assessments through varying the time of exposure were ranged between 30 % and 50% for the exposed time, $27{\sim}37%$ for tonality, and $34{\sim}20%$ for loudness, respectively With these results, hopefully, it can be helpful for those who want to work out an experimental design for evaluating an environmental noise or to quantify any psychological dimensions found in annoyance assessments.

• 한국전산구조공학회논문집
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• 제36권4호
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• pp.233-242
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• 2023

본 논문에서는 다중 시그마포인트 세트(MSP)를 사용하는 분산점 칼만필터(UKF)인 UKF-MSP를 소개한다. 비선형 동적시스템을 표현하기 위해 널리 알려진 Bouc-Wen 모델을 사용하였고, 비선형성 고려가 가능한 칼만필터 중 UKF를 선정하였다. 그런데 UKF는 두 가지 인공오차와 시그마포인트의 분포를 결정하는 스케일링 파라미터의 값을 튜닝(Tuning)하는 과정을 통해 적절히 설정해야만 대상 동적시스템의 추정하고자 하는 상태(State)를 정확히 추정할 수가 있다. 본 논문에서는 후자의 스케일링 파라미터 설정 문제를 완화하고자 하였으며, MSP를 사용함으로써 기존 UKF에 비해 칼만필터 튜닝 과정에 덜 민감한 UKF-MSP를 제안하였다. 지진으로 인한 급격한 구조손상 시나리오에 대해 UKF-MSP의 안정성을 검증하였다. 제안된 방법은 튜닝과정을 완화함과 동시에 다른 칼만필터 파라미터인 인공오차에 대해서도 덜 민감한 거동을 보임을 확인하였다.

• 한국음향학회지
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• 제32권3호
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• pp.252-261
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• 2013

일반적인 음성인식 시스템은 조용한 인식 환경에서는 높은 인식성능을 나타내지만 잡음이 존재하는 실제 환경에서는 그 성능이 급격히 저하한다. 본 논문에서는 다양한 잡음환경에서도 강인한 음성인식기를 구현하기 위하여, 주파수의 변이도를 이용하여 음성인식을 위한 환경 정보를 얻고 이를 음성 인식을 위한 모델 개선에 적용하여 성능향상을 도모하는 환경정보 지식에 기반한 주파수 변이 적응 PMC (Parallel Model Combination adaptation using frequency-variant based on environment - awareness : FV-PMC) 방법을 제안한다. 이 방법은 미리 분류된 각 잡음 군간의 평균 주파수 변이도를 미리 계산하여 임계치로 설정하고 미지의 잡음이 포함된 음성이 입력되면 각 잡음 군과의 주파수 변이도를 다시 계산하여 해당 잡음군의 임계치 보다 높을 경우 그 잡음 군의 잡음이 포함된 음성으로 간주하여 이 잡음 군이 포함된 음성을 이용하여 생성된 인식모델을 이용하여 음성인식을 수행한다. 제안한 FV-PMC 방법을 이용하여 잡음을 분류 하였을 경우 평균 분류 정확도는 56%를 보였고 이를 이용해 음성인식 실험을 실시한 결과 Set A의 평균인식률은 79.05%, Set B의 평균인식률은 79.43%, Set C의 평균인식률은 83.37%로 나타났다. 전체 평균인식률 80.62%로 기존의 깨끗한 모델을 이용한 PMC 인식률 74.93% 보다 5.69% 향상된 결과를 보여 제안한 방법의 유효성을 확인할 수 있었다.

• 정보보호학회논문지
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• 제32권5호
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• pp.881-890
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• 2022

다양한 장소에서 드론이 활발하게 이용되면서 비행금지구역 내 불법 침입, 정보 유출, 항공기 충돌 등의 위험이 증가하고 있다. 이러한 위험을 줄이기 위해 비행금지구역으로 침입하는 드론을 탐지할 수 있는 시스템 구축이 필요하다. 기존의 드론 음향 탐지 연구는 탐지 모델에 환경 소음에 노출된 드론 음향을 그대로 학습시켰기 때문에 환경 소음에 독립적인 성능을 얻지 못했다. 이에 본 논문에서는 다양한 공간에서 환경 소음에 노출된 드론 음향을 명확하게 탐지하기 위해 주변 환경 소음을 별도로 수집하고, 드론 음향 신호에서 환경 소음을 제거하여 시끄러운 환경 속에서도 견고한 성능을 나타내는 범용적인 드론 탐지 시스템을 제안한다. 제안하는 시스템은 수집한 드론 음향 신호에서 환경 소음을 제거한 후 Mel Spectrogram 특성추출과 CNN 딥러닝을 이용하여 드론 존재 여부를 예측하였다. 실험 결과, 환경 소음으로 인해 감소했던 드론 탐지 성능을 7% 이상 향상시킴을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.131-133
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• 2000

Single phase simulations were carried out in order to determine a solutive conductor to the aeolian noise which will be locally applied to 765 kV transmission lines Basic solutive conductors have already been proposed including conductors equipped with spiral rod. low noise conductor of a special shape and others. A low aeolian noise conductor, however, should have excellent corona characteristics in addition to aeolian noise reduction function. In this paper, we compared the performances of the audible noises and radio interferences of 6 candidate conductor bundles by using corona cage. We also developed two programs to need for evaluating environmental effects of each conductor bundle. Those are a program to calculate the conductor surface gradient of various special bundles and a conversion program of single phase data to the model of transmission line. The future determination on the final low aeolian noise conductor will be made through a long-term test to verify environmental impacts at the full-scale Kochang 765 kV test line.

• 전자공학회논문지SC
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• 제43권4호
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• pp.60-66
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• 2006

장비를 사용해서 해양자원을 탐사하고 개발하기 위해서 수중초음파 통신은 유용한 수단이 된다. 이러한 응용을 위해서는 정보전달 및 원격제어가 필수적인데, 해양환경에서 다양한 형태의 노이즈가 발생하여 제어의 효율성과 수중통신의 신뢰성이 저하 되고 있다. 그래서 기존의 방법은 하드웨어적인 방법으로 제어정보를 수신하고 이를 반복적으로 기준 정보와 비교하는 방법을 사용하고 있어 제어신뢰성이 중요시되는 시스템에서는 효율성이 떨어지고 있다. 따라서 본 연구에서는 해양환경 변화에 따른 영향이 없이 초음파 신호를 인식할 수 있는 수중 초음파신호 검출성능 향상 알고리듬을 제안하려 한다. 제안하는 알고리듬의 적합성을 시뮬레이션을 통하여 확인하였다.

• Smart Structures and Systems
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• 제6권9호
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• pp.1025-1039
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• 2010

Measuring displacement response for civil structures is very important for assessing their performance, safety and integrity. Recently, video-based techniques that utilize low-cost high-resolution digital cameras have been developed for such an application. These techniques however have relatively low sampling frequency and the results are usually contaminated with noises. In this study, an integrated visual-inertial measurement method that combines a monocular videogrammetric displacement measurement technique and a collocated accelerometer is proposed for displacement and velocity measurement of civil engineering structures. The monocular videogrammetric technique extracts three-dimensional translation and rotation of a planar target from an image sequence recorded by one camera. The obtained displacement is then fused with acceleration measured from a collocated accelerometer using a multi-rate Kalman filter with smoothing technique. This data fusion not only can improve the accuracy and the frequency bandwidth of displacement measurement but also provide estimate for velocity. The proposed measurement technique is illustrated by a shake table test and a pedestrian bridge test. Results show that the fusion of displacement and acceleration can mitigate their respective limitations and produce more accurate displacement and velocity responses with a broader frequency bandwidth.

• The Journal of the Acoustical Society of Korea
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• 제18권3E호
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• pp.30-36
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• 1999

In this paper, we develop a hybrid speaker recognition system [1] enhanced by pre-recognizer and post-recognizer. The pre-recognizer consists of general speech recognition systems and the post-recognizer is a pitch detection system using adapted continuous wavelet transform (ACWT) to improve the performance of the hybrid speaker recognition system. Two schemes to design ACWT is considered. One is the scheme to search basis library covering the whole band of speech fundamental frequency (speech pitch). The other is the scheme to determine which one is the best basis. Information cost functional is used for the criterion for the latter. ACWT is robust enough to classify the pitch of speech very well, even though the speech signal is badly damaged by environmental noises.