• Title/Summary/Keyword: Specific Noise

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Comparing Highway Traffic Noise Emission Levels Using Individual UofL State - specific Data - Based on Open Space - (루이빌대 개별State-specific 데이터를 이용한 도로 교통소음 수준 비교 - 오픈공간에서 -)

  • Teak K.;Roswell A. Harris;Louis F. Cohn
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.4
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    • pp.276-286
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    • 2004
  • 현재. 미 연방도로부에서는 도로교통소음분석을 위한 예측모형 (TNM & STAMINA)을 미 전 지역에 제공하고 있고, 이와 관련된 여러가지 연구논문들이 수행되고 있는바, 모델을 이용한 예측치와 실측치 간의 비교$.$분석 연구논문을 통하여 차이점이 존재하는 것을 증명하고 있다. 따라서 본 연구논문은 소음예측모형의 핵심자료로 사용될 수 있는 루이빌대(UofL) 회귀모형들을 차종별 (소형, 중형, 대형) 그리고 주별 (아리조나. 콜로라도, 조지아, 캔사스, 와싱톤)로 구분하여 그 차이점을 통계적으로 비교$.$분석$.$결론을 도출하였다. 그 결과 아리조나와 콜로라도(중대형)를 제외한 나머지 개별 State-specific데이터는 통계적으로 서로 다른 것으로 나타났다.

Survey on the Mean Opinion Scores on the Sound Level of Mobile Phone Ring Tones (이동전화 벨소리 소음에 대한 호감도 조사)

  • 유성모;박승근
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.6
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    • pp.23-27
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    • 2000
  • Noise can be defined as any undesired or loud sound. The sound level of mobile phone ring tones could be considered as noise if it is too loud on a specific situation. To classify a specific sound level of mobile phone ring tones as noise, it is useful to evaluate the mean opinion scores(MOS) on sound levels under some specific situations. The paper evaluates MOS on various sound levels (in dBA) of mobile phone ring tones, types of ring tone(bell/melody), and gender(male/female), location (street/office).

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An Experimental Study of the Influences of Basic Design Parameters on the Performance and the Noise Characteristics of Cross-flow Fans (직교류 홴의 설계인자가 성능 및 소음 특성에 미치는 영향에 대한 실험적 연구)

  • 구형모
    • Journal of KSNVE
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    • v.10 no.3
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    • pp.430-436
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    • 2000
  • The cross-flow fans have been widely used to constitute the air moving systems in many air-ventilating and air-conditioning units. The cross-flow fan system has many design parameters which have crucial influence on the performance and the noise characteristics of the units. As a result there are many difficulties in the design stage of the system and the general design guide has not been sufficiently established yet. This study presents the experimental results of the parametric investigation of some chosen design parameters which are directly related to the shape of the stabilizer the profile of the scroll casing and the diffusion angle of the flow exit. The results are expressed in terms of the fan performance and the specific sound pressure level characteristics. Some parameters have been found to have crucial effects on the system performance/noise characteristics and should be considered with care in the design stage.

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Environmental Noise Evaluation of the Boundary Areas for 1200MW Combined Cycle Power Plant (1200MW 복합화력 발전소가 부지경계에 미치는 환경소음 예측)

  • 이현;김연환;김희수;배용채;김성휘
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.1056-1061
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    • 2001
  • This paper describes the evaluation of noise influence of residental and boundary areas from power plant noise sources of 1200MW combined cycle power plant. Noise assessments are carried out by based on the ISO 3744, ISO 9613-1 and ISO 9613-2 to predict the noise distribution to satisfy the recommended noise level at specific locations and to calculate properly the octave noise power of main noise sources such as power transformers. air-intakes, stacks.

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Analysis and Improvement Specific Frequency Reception Noise Phenomena Due to RF Radiation Signal (RF 방사 신호로 인한 특정 주파수 수신 잡음 현상의 원인분석 및 개선)

  • Kwon, Jung-Hyuk;Kim, Jong-Min;Lee, Wang-Sang
    • Journal of Aerospace System Engineering
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    • v.16 no.3
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    • pp.73-83
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    • 2022
  • The purpose of this paper was to identify a method to improve received noise in a specific frequency band, caused by RF radiation signals during aircraft operation. The communication equipment of the aircraft is critical to the performance and safety of the flight mission, as it is responsible for the function of internal and external communications. Noise-free, clean communication quality, as well as transmission and receiving functions have to be implemented. Thus, the cause analysis of the reception noise in a specific frequency band, was analyzed through trouble shooting. The receiving noise due to the RF radiation signal emitted from the subsystem unit inside the aircraft, was improved by shielding with a CAP with electroless nickel plating applied. Additionally, the measurement and verification results of the improvement method are also described.

DEVELOPMENT OF EFFICIENT METHODS TO REDUCE THE EMITTED NOISE LEVELS OF APPLIANCE DRAIN PUMPS

  • Ozturk, Cuneyt
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06a
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    • pp.716-721
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    • 1994
  • The goal of this study is to develop treatment methods for improving the noise quality of Home Appliance Drain Pumps. Developed treatment methods covers the various methods including the control of the water level through the developed electronic circuity and the various modifications over the design of impeller and fan units. In the first part of the studies Dominant noise sources of the pumps are analyzed. Specific noise problems of the pumps are classified on the basis of mechanic and magnetic origins. Factors including the pressure variations at suction head, magnetic interactions with structure, specific fan noises are studied sequentially. The second part of the studies are considered for development and application of treatment methods. Results denoted the basic problems and ways to improve the noise quality by treating the dominant soureces of drain pumps.

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Study on the Optimal Location Selection for Environmental Noise Monitoring Systems (환경소음측정망 최적 위치선정에 관한 연구)

  • Shin, Sangmun;Won, Jeongwoo;Kim, Hwail
    • Journal of Environmental Science International
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    • v.23 no.7
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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.

Prediction of the Noise Levels for a Newly-founded Petrochemical Plant (신설 석유화학 공장의 소음도 예측)

  • 윤세철;이해경
    • Journal of the Korean Society of Safety
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    • v.11 no.4
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    • pp.135-142
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    • 1996
  • Prolonged in-plant personnel exposure to high noise levels results in permant hearing damage. There are no way to correct this hearing damage by treatment or use of hearing aids. Therefore, every employer is responsible for providing a workplace free of such hazards as excessive noise. This study was carried out to evalute and predict a given noise environment based on specific limit as the noise guarantee for a newly-founded petrochemical plant. The maximum total sound level should not exceed 85dBA in the work area, except where the area is defined as a restricted area and 70dBA at the plant boundary. Prediction of the noise levels within the plant area for a newly-founded petrochemical plant was achieved by dividing all plant area into 20m$\times$20m regular grid spaces and noise level inside the area or unit that in-plant personel exposure to high noise levels was estimated computed into 5m$\times$5m regular grid spaces. The noise level at the grid point that was propagated from each of the noise sources(equipments) computed using the methematical formula was defined as follows : $SPL_2$=$SPL_1-20log{\frac{r_2}{r_1}}$(dB) where $SPL_1$ =sound pressure level at distance $r_1$ from the source $SPL_2$=sound pressure level at distance $r_2$ from the source As a result, the equipments exceeded noise limit or irritaring noise levels were identified on the specific grid coordinates. As for equipments in the area that show high noise levels, appropriate counter-measures for noise control (by barriers, enclosure, silencers, or the change of equipments, for example) should be reviewed. Methods for identifying sources of noise applied in this study should be the model for prediction of the noise levels for any newly-founded plant.

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Assessment Method of Noise Exposed Population for Manufacture Type of Noise Map (소음지도제작방법에 따른 소음노출인구산정방법)

  • Park, In-Sun;Oh, Jong-Hwa;Park, Sang-Kyu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1129-1133
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    • 2007
  • Assessment of noise exposed population is a method for checking the degree of environmental noise 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 reduction policy and action plan by accurately assessing the area that noise causes harm to human health. Recently, a noise map, which can predict noise in comprehensive areas, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for the noise can be considered more effectively by using assessment methods of noise exposed population for specific noise levels, areas, and building types which are the main input factors in noise maps. In this study, Assessment methods of noise exposed population by using 2D noise map are compared with those by 3D noise map.

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Comparative Study on Annoyance of Traffic and Aircraft noise (도로소음과 항공기소음의 성가심 반응 비교 연구)

  • Lee, Ki-Jung;Chang, Seo-Il;Lee, Kun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.131-134
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    • 2005
  • This study examine the annoyance of transportation noise exposure and found the survey method about which noise induces more disturbance or annoyance when more than two kinds of noise exist. This study describes the noise annoyance survey performed in the vicinity of Sin-wol interchange. This residential area was exposed to aircraft noise and traffic noise simultaneously and aircraft noise exposure of this area is about 81 WECPNL, traffic noise exposure is about 81.2 dB(A) nearby road. Noise sources are grouped into three part, traffic noise, aircraft noise and community noise. The questionnaire includes how often, how loud each noise is heard. Also this deals with comparative annoyance reaction from specific noise sources such as aircraft or traffic and its disturbance of daily activities. Facade noise mapping are executed by using a commercial noise mapping software.

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