소음지도를 이용한 금속재료품 제조공정의 소음저감 순위 결정

김병삼 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.2

Assessment of noise exposed population is to check the environment noise level and social influence in order to reduce the risks such as annoyance and disturbance that are generated by environmental noise. Also, this method suggests the preferential noise abatement policy and action plan by accurately finding the area that the noise causes harmful effect to human health. Recently, a noise map, which can predict noise in comprehensive area, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for noise can be considered more effectively by using assessment methods of noise exposed population for specific noise level, area, and building types which are the main input factors in noise maps. In this study, we propose noise reduction ranking decision at manufacturing process of metal material products due to noise map.

Noise-reduction Function and its Affecting Factors of Plant Communities

( Xiu-hua Song ),( Qian-qian Wu ),( Dong-ming Yu ),( Piao Yong-ji ),( Tae-dong Cho ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.10

In this study, we investigated the relationship between noise reduction and the community structure of nine groups of typical plant communities as well as the reduction in noise at different frequencies. The semantic differential method was adopted to explore the perception of noise reduction. The results indicated that there was a significantly positive correlation between noise reduction and coverage , a significantly negative correlation between noise reduction and bifurcate height, and a negative correlation between noise reduction and bare rate. However, there was no significant correlation between noise reduction and height, diameter at breast height, or crown width. The reduction of middle-frequency noise was better than that of low- and high-frequency noise. The indicators "quiet" and "calm" showed that plant communities could reduce the noise perceived by humans. However, overly dense woodland caused nervousness, fear, depression, and other negative effects. Relatively open environments and those with large forest gaps obtained the highest evaluation.

영국의 소음규제 법제

이은기 ( Eun Gi Lee ) 한국환경법학회 2009 環境法 硏究 Vol.31 No.3

소음은 우리 일상생활의 결과이면서도 청력손상, 수면장애, 불쾌감 등으로 생활환경을 악화시키는 요소이다. 소음에 대한 반응은 매우 주관적이며 다른 환경오염형태와는 달리 독이 되지는 않으며 피해가 축적되지는 않는다. 영국은 1800년대부터 소음에 관한 많은 판례가 축적되었고 불문법국가임에도 적지 않은 실정법을 통해 적절한 행정적·사법적 규제를 해 왔는바, 소음규제 및 소음피해구제에 있어서는 매우 선진적이다. 영국의 소음규제법규로는 환경보전법(EPA), 피해구제법(COPA), 소음법(NA), 소음·법정불법방해법(NSNA), 건물규정, 실행지침 등 수많은 법령이 있다. 생활소음에 대해 불만이 제기되면 지방행정기관이나 지역의회가 신속하게 소음배제통지를 하고 이를 준수하지 않으면 형사범죄가 됨은 물론 사적 불법방해를 넘어 공적 불법방해까지도 성립할 수 있다. 경범법원(magistrates` court)에의 불복절차, 지역법원(district court) 등 각 심급법원에의 사법절차를 통하여 사전적·사후적 구제를 하고 있다. 영국소음규제법제의 법정불법방해(Statutory Noise Nuisance), 소음배제통지(Noise Abatement Notice)제도, 건축공사장소음에 대한 사전 동의제(Prior Consent), 건물규정(Building Regulations) 등에서의 집단주택의 이웃 및 층간 소음규제 등 세밀하게 다양한 형식의 규제를 하고 있으며 법원의 금지명령(Injunction)에 의한 피해의 최소화를 꾀하고 있다. 위와 같은 행정적 규제와 함께 보통법의 법정불법방해법제에 의한 영국의 소음피해배상방식은 아직도 행정적 구제보다는 사후적 민사구제에 의존하고 있는 우리의 소음규제법제에도 많은 시사를 주고 있다. I have been concerned about noise problem for a long time, since I have so acute sense of hearing as to be sensitive to a slight noise. Sensitivity and subjectivity of individual are the distinctiveness relating to noise problems. This article concerns English noise regulation system and lots of noise related cases to introduce it in our country. UK has developed noise related case-law and regulative legislations since 1800`s. This article explores the method to deal with various aspects of noise disturbance in England. They approach noise problems by means of common law`s private nuisance and public nuisance. A public nuisance is both a tort and a criminal offence. For one example, the Attorney General may seek an injunction to prevent a public nuisance. They have main statutory provisions which relate to noise such as Control of Pollution Act 1974, Environmental Protection Act 1990, Noise and Statutory Nuisance Act 1993, Noise Act 1996 and etc. Section 80 of the EPA 1990 provides that an authority must serve an Abatement Notice on the person responsible when a statutory nuisance exists or likely to occur. I think those system stated above are available and useful to prevent adverse noise in advance in England. And they use the grant of planning permission to minimize the adverse effect of noise in the course of development. UK`s court has held a lot of decisions on noise problem according to the principles of common law. I introduced those decisions from time to time in this article to understand English mechanism of noise pollution problems. In conclusion, there are very desirable types of noise regulations such as Noise Abatement Notice, Statutory Noise Nuisance, Building Regulations concerning to neighbourhood noise problem and Prior Consent system at construction site in UK. They give us lots of learnable suggestions. I suggest to introduce such regulative legislations to heighten environmental quality of our life. I think that is one of shortcuts to achieve "the Green Growth" which is Korean government`s catch phrase.

소음지도에 의한 선박 건조 및 수리 공정의 소음저감 순위 결정

서양,김병삼 한국기계기술학회 2017 한국기계기술학회지 Vol.19 No.5

Assessment of noise exposed population is to check the environment noise level and social influence in order to reduce the risks such as annoyance and disturbance that are generated by environmental noise. Also, this method suggests the preferential noise abatement policy and action plan by accurately finding the area that the noise causes harmful effect to human health. Recently, a noise map, which can predict noise in comprehensive area, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for noise can be considered more effectively by using assessment methods of noise exposed population for specific noise level, area, and building types which are the main input factors in noise maps. In this study, we propose noise reduction ranking decision at ship construction and repair process due to noise map.

Noise Exposure Assessment in a Dental School

Choosong, Thitiworn,Kaimook, Wandee,Tantisarasart, Ratchada,Sooksamear, Puwanai,Chayaphum, Satith,Kongkamol, Chanon,Srisintorn, Wisarut,Phakthongsuk, Pitchaya Occupational Safety and Health Research Institute 2011 Safety and health at work Vol.2 No.4

Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ${\pm}$ 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

Study on the Reduction of Gear Whine Noise in Diesel Engine Gear Train

Qi Zhang(장기),Yong Bo Wang(왕용보),Jian Hua Lv(려건화),Zhong Gang Zhu(주중강),Zhen Qin(진진),Sung Ki Lyu(류성기) Korean Society for Precision Engineering 2019 한국정밀공학회지 Vol.36 No.9

Noise, Vibration and Harshness (NVH) is a comprehensive issue of manufacturing quality that gives the purchaser a superficial feeling. The NVH performance of the vehicle has undoubtedly become an important factor and basis for consumers. When the internal combustion engine is working, it generates a strong noise thus making it necessary to reduce the vibration and noise. The noise of diesel engine is divided into acoustic and structural radiation noise according to different radiation paths. The structure radiated noise is mainly caused by the combustion noise and mechanical transmission noise, while mechanical transmission noise is mainly generated by the meshing gears in the diesel. This paper aims to solve the problem of a diesel engine abnormal gear whine noise under idling conditions with a combination of simulation and experiment. By gear micro-modification, the gear train whine noise is reduced by minimizing the PPTE of the gear train. The comparison of the simulation to benching testing shows a good correlation. It provides an optional solution to the modification proposal of the engine gear train, which uses the similar structure for the engine. Future work will dwell on a better understanding of the gear rattle noise, which will be discussed later.

The Relationship Between Pure-tone Noise and Human Bio-signal Response

조원학,황성호,최현기 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

The experiences of stress are common to all living things. Noise is one of the most widespread sources of environmental stress. Noise is a pervasive aspect of many modern community and work environments. So, it is important to consider noise when we design human-oriented products. This study investigates the responses of electrocardiogram (ECG) and eye tracker data in order to evaluate the direct effects of low, middle, and high frequency noise on the two main physiological stress axes: the autonomic nervous system, and cognitive responses for a human-oriented product design. A subject was exposed to low (100 Hz), middle (1000 Hz), and high frequency (100000 Hz) noise while awake. ECG and eye tracker data were collected during noise exposure. Sympathetic nervous system (SNS) activity was less in the low and high frequency noise ranges compared to the no sound. On the other hand, parasympathetic nervous system (PNS) activity was greater in the low and high frequency noise ranges than the SNS activity in the no sound. The cognitive responses or latency saccadic eye movement (LSEM), in low or high frequency noise was greater than that in the no sound. And results of EEG and eye movement were statistically significant in low and high frequency noise (r > 0.93, p < 0.05). The findings of this study indicate that the stress induced by low frequency noise is as stressful as the stress induced by high frequency noise. Additionally, utilizing eye tracker data and acquiring the LSEM is useful in the analysis of human stress responses during various stressful situations in addition to the analysis of human stress responses during noise exposure.

균질 반도체의 과잉 잡음에 관한 해석적 식

박찬형(Chan Hyeong Park),홍성민(Sung-Min Hong),민홍식(Hong Shick Min),박영준(Young June Park) 대한전자공학회 2008 電子工學會論文誌-SD (Semiconductor and devices) Vol.45 No.9

균일하게 도핑된 반도체에서, 분포된 확산 잡음원에 의해서 발생하는 단자잡음전류의 전력주파수밀도를 계산하였다. 고정된 전압에서 반도체의 길이가 작아짐에 따라, 또는 주어진 반도체에서 전류레벨이 증가함에 따라, AC 단락잡음전류는 열잡음 뿐만 아니라 과잉잡음을 보인다. 이 과잉잡음은 채널길이가 외인성 Debye 길이에 비해 매우 작은 경우에는 산탄잡음의 스펙트럼과 같은 모습을 보인다. 유한한 주파수에서 속도요동 잡음원에 의한 외인성 반도체에서 발생하는 과잉잡음을 최초로 유도하였다. 유도된 과잉잡음 공식은 반도체 채널의 통과 시간, 유전 이완 시간, 속도 이완 사이의 상호 작용에 따라 단자잡음 전류와 캐리어 농도 요동이 결정됨을 명시적으로 보여준다. 또한 유도된 해석적 식을 사용하여 여러 가지 반도체 샘플 길이와 바이어스, 주파수에 따른 잡음 스펙트럼의 변화도를 계산하였다. 유도된 공식은 quasi-ballistic 수송현상이 중요한 역할을 하는 나노스케일 MOSFET의 잡음 발생 기제를 이해할 수 있는 기반이 된다. Noise in homogeneous extrinsic semiconductor samples is calculated due to distributed diffusion noise sources. As the length of the device shrinks at a fixed bias voltage, the ac-wise short-circuit noise current shows excess noise as well as thermal noise spectra. This excess noise behaves like a full shot noise when the channel length becomes very small compared with the extrinsic Debye length. For the first time, the analytic formula of the excess noise in extrinsic semiconductors from velocity-fluctuation noise sources is given for finite frequencies. This formula shows the interplay between transit time, dielectric relaxation time, and velocity relaxation time in determining the terminal noise current as well as the carrier density fluctuation. As frequency increases, the power spectral density of the excess noise rolls off. This formula sheds light on noise in nanoscale MOSFETs where quasi-ballistic transport plays an important role in carrier transport and noise.

의료 영상 시스템 기반 Fast non local-Means (FNLM) 알고리즘의 적용 가능성

유원종(Won-Jong Yu),강성현(Seong-Hyeon Kang),이용구(Yong-Gu Lee),이영진(Youngjin Lee) 대한전자공학회 2018 전자공학회논문지 Vol.55 No.3

의료진단 분야에서 X-ray를 이용한 진단 비중이 꾸준히 증가하고 있으나, 영상 내에 발생하는 noise로 인해 병변에 대한 정보 획득에 어려움이 있다. 이러한 noise를 제거하기 위해 median, Gaussian, Wiener와 같은 알고리즘이 개발되었으나 영상의 윤곽에 대한 선예도가 감소되어 해상력을 감소시키는 문제가 발생한다. 따라서, 본 논문에서는 선예도를 유지하며 noise를 제거할 수 있는 fast non-local means (FNLM) 알고리즘을 모델링하여 X-ray 기반 영상에서의 유용성을 평가하고자 한다. 연구 방법은 MATLAB을 이용하여 Gaussian noise를 모델링 한 Shepp-Logan phantom 영상을 획득한 후 median, Gaussian, Wiener 그리고 FNLM 알고리즘을 각각 적용하였다. 또한, 영상의 정량적 평가를 위해 설정한 두 개의 ROI 영역에서의 coefficient of variation (COV), contrast to noise ratio (CNR) 및 signal to noise ratio (SNR)을 측정하였다. 결과적으로, FNLM 알고리즘을 적용하였을 경우 noise를 추가시킨 원본영상에 비하여 COV, CNR 그리고 SNR이 약 3.16배, 7.47배 그리고 9.19배 향상되는 것을 확인할 수 있었다. 결론적으로, 본 연구결과를 바탕으로 FNL 알고리즘을 의료영상에 적용할 경우 noise를 효과적으로 제거할 수 있음을 증명하였고, 나아가 임상 적용 가능성을 확인할 수 있었다. The proportion of diagnosis using X-ray is continuously increasing in field of medical diagnosis, but it is difficult to obtain information about the disease due to noise in the image. Although median, Gaussian and Wiener filters were developed to reduce noise, these have major problems for degradation of spatial resolution with decreasing sharpness for edge information. Therefore, we evaluated the usefulness of fast non-local means (FNLM) algorithm to maintain sharpness and remove noise. Shepp-Logan phantom image with Gaussian noise was obtained using MATLAB program and then applied median, Gaussian, Wiener algorithm, respectively. Also, we measured coefficient of variation (COV), contrast to noise ratio (CNR) and signal to nosie ratio in applied two ROI regions for quantitative evaluation of image quality. As a result, in case of applied FNLM algorithm in image, COV, CNR, and SNR were improved about 3.16, 7.47 and 9.19 times, respectively. In conclusion, based on the results of this study, we demonstrated that the FNLM algorithm can effectively remove noise in medical images and confirmed possibility of clinical application.

소음과 수면양상에 관한 연구 : 중환자실을 중심으로

손연정 성인간호학회 2001 성인간호학회지 Vol.13 No.2

The environment in the ICU leads to negative changes in a patient's usual sleep pattern and so contributes negatively to the patient's health wards. Therefore, it is thought that an important nursing intervention would be to identify the relation between noose and sleep patterns which play an important role in illness recovery. The purpose of the present study was to explore the relationship between noise in the ICU and the sleep pattern of patients admitted to the ICU. A descriptive correlation design was used to examine the relationship. Thirty-four subjects were recruited from a Medical ICU (MICU), Surgical ICU (SICU) and Coronary Care Unlt (CCU) at a large university hospital in Suwon. Data were collected from September 28 to October 31 in 1999. In the present study. noise was categorized into noise level and patients' perception of noise. The objective noise level was measured using the A-Weighted Sound Level Meter. The patients' preception of noise was measured using a self-reported questionnaire developed by the researcher. Sleep patterns in this study includes both quantity and quality of sheep. These were measured using open ended questionnaires and the 'Korean Sleep Scale A developed by Oh, Song, Kim(1998). The data was analyzed using the SPSS-WIN to test the research questlon. Pearson moment correlation coefficient was run. Ancillary analysis were conducted with demographic vairables to determine their relation to the malts study variables. For the ancillary analysis, t-test and one-way ANOVAs were performed. The results of the present study are summerized as follows : 1. The total mean of objective noise level (10pm-yam) was 56.2dB. The means for night time noise level in individual ICUs for the SICU, MICU and CCU, were 58.7dB, 58.6dB and 48.3dB, respectively. The total mean for patlents' noise perception was 42.8 out of a maximum possible score of 76. For item means of noise perception, the one ranked hightest was "conversations" between doctors and nurses″(3.2). The one ranted lowest was ″noise from the radio″(1.2). Regarding the degree of perception for each type of noise source, the one ranked highest was ″equipment noise″(2.6), the second was the third was ″conversation between patients, caregivers and visitors″(2.3), and the one ranked lowest was ″environment noise″(1.8). 2. Looking at quantity of sleep of ICU patients, the mean nocturnal sleep time was found to be 4.9 hours. The total mean of sleep quality for ICU patients was 21.0 out of a maximum possible score of 40. 3. The relationship between perception of noise and quantity or sleep was statistically significant(r= -.41, p<05). The relationship between perception of noise and quality of sleep was also statistically significant(r= - .47, p<.01). The results of the study indicate that personal perception of noise is related to patterns. Therefore, it is suggested that nursing interventions be developed to reduce the degree of personal perception of noise and, thus, decrease sleep pattern disturbances in patients in the ICU.