• 제목/요약/키워드: Measurement noise

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단기간 소음도의 대표성 확보를 위한 소음도 추출기법 연구 (A Study on Sampling Techniques to Assure the Representativeness of Short-term Equivalent Noise Level)

  • 류훈재;고준희;장서일;이병찬
    • 한국소음진동공학회논문집
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    • 제22권12호
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    • pp.1213-1219
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    • 2012
  • The purpose of this study is to present a guideline to design a short-term manual measurement of environmental noise level, which is more economical and flexible, but less representative than long-term automatic measurement. The proposed guideline can provide the number of measurement times and the length of measurement term required to secure the extent of the representativeness. The data was collected at 4 sites located in Seoul and at 4 sites located outside of Seoul. The probabilities for five-minute equivalent noise levels, Leq, 5min, to stay in an error range from the quarterly representative noise level were used to evaluate sampling techniques. The probability analysis of the daytime period showed that the noise levels measured between 10 am and 2 pm and between 9 pm and 10 pm have the probabilities higher than 60 %. On the other hand, even for the same length of total measurement time, increasing the number of random samplings results in higher probabilities than increasing the length of measurement term.

대형 Ro-Ro Ferry의 방음 설계 (A Noise Control of a Ro-Ro Passenger Ferry)

  • 김동해;박종현
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.738-741
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    • 2003
  • In general, the essential requirement for cruisers or car ferries is the reduction in noise to ensure high quality and comfort. Recently, the Ro-Ro Passengers Ferry (ROPAX) was built in Hyundai Heavy Industries. In order to minimize the noise levels, careful attention have to De paid by the special committee of experts from the initial design stage to the sea trial. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various experiment results. Finally, this ship was successfully delivered with excellent noise properties. This paper describes the procedure of noise analysis, the countermeasures of noise control, and the measurement results of the sea trial. Onboard noise analysis had been carried out by statistical energy analysis program and outdoor noise prediction program based on ISO9614. The prediction results are in good agreements with the measurement results. The technology to minimize the noise levels for cruisers or car ferries has been established throughout the construction of this ship.

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항공기 소음 측정 시 이동측정지점에 대한 소음도 예측방법 (A Noise Prediction Method on the Movement Measuring Points at Measurement for Aircraft Noise)

  • 우정하;이병찬
    • 한국소음진동공학회논문집
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    • 제25권12호
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    • pp.901-906
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    • 2015
  • It is difficult to measure aircraft noise at many points, because the noise measurement is need to long time, 24 hours and consecutive 7 days, which results in high costs. As an alternative, movement measuring points are set to measure aircraft noise for less than 24 hours, and so it is needed to overcome the limitation of shorter measuring time. Thus, this study measured military aircraft noise on movement measuring points and conducted a comparative analysis on the data according to each measuring time. The data of measuring noise for 24 hours and less than 24 hours were compared to suggest appropriate measuring time on the movement measuring points. As a result of comparing data of measuring noise, an error was within 3 dB in case of measuring time of 3 hours, and an error was within 1 dB in case of 6 hours of measurement.

한국형 고속철도 차량의 운행조건에 따른 차내 소음 분석 (An interior noise analysis of KTX vehicles on various operating conditions)

  • 최성훈;김재철;이찬우;문경호
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(III)
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    • pp.138-142
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    • 2003
  • The conditions for measurement of the interior noise should meet the international standards. However, due to the limitations in test conditions the possible errors in measurement equipment, reliability of the measurement results has been questioned. Hence, the test procedure for the interior noise measurement of KTX vehicles are reviewed and investigated with the reference of international standards. Furthermore, the acceptable tolerance is inspected through the analysis of the factors that influence the interior noise of the KTX vehicle.

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소형 무인 로봇의 소음 측정법 개발 및 측정 장소에 따른 상관성 분석 (Noise Measurement Method Development and Correlation Analysis According to Measurement Location of Small Unmanned Robot)

  • 옥진규;박은주;박민수;이명천
    • 한국군사과학기술학회지
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    • 제20권5호
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    • pp.633-638
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    • 2017
  • The small unmanned robot developed in this paper can perform tasks such as surveillance and reconnaissance in the battle field. The noise generated during the operation of the robot may expose the operation area. Therefore, in this study, we developed a method to quantitatively measure the noise of the developed small unmanned ground robot. The criteria for noise measurement in indoor and outdoor are presented. It was used for statistical verification method to verify the reliability of the developed noise measurement method. The noise was measured at different places, and the correlation was analyzed. Thus, we proposed a method to predict the noise level in the operation area where the robot is operated by the noise test data measured during the development process.

선박 방사소음의 측정방법 및 정확도 해석 (Ship Radiated Noise Measurement Methods and Accuracy Analysis)

  • 이필호;윤종락
    • 한국소음진동공학회논문집
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    • 제15권6호
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    • pp.738-748
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    • 2005
  • The ship radiated noise level fluctuates by the difference of interference and reverberation according to measurement methods and environmental conditions. These phenomena cause error of the source level estimation even in the same environment conditions. This paper describes a quantitative analysis and a reduction method for an error value to the source level estimation in spatial and temporal interference environment. The design criteria of the radiated noise measurement array composed of omni-directional hydrophones and the source level accuracy in the deep water range are given. The source level accuracy in the shallow water range is also derived based on the statistical model of the multiple reflection paths. The results are verified using the water tank experiment and the sea trial.

공동주택 외부소음 현장측정방법 (Field Measurements of Exterior Noise at Apartment Houses)

  • 송민정;정성수;장길수;김선우
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계학술대회논문집
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    • pp.359-362
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    • 2005
  • Road traffic noise level and railway noise level are important factors on apartment inhabitant's comforts. The measurement methods which noted by Ministry of Construction & Transportation(MOCT) and Ministry of Environment(ME) are used for measurement of exterior noise at apartment houses. But these methods are out of date because the height of apartment houses have increased dramatically and owing to the sampling methods of the measurement time interval, rating values are induced differently due to sampling methods. In this study, the sound level of each floor of apartment houses is measured and compared. And rating value due to sampling methods are compared. As a result, the KS outline of 'Field Measurement of Exterior Noise at Apartment Housess' is suggested.

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무궁화 열차의 소음 측정 및 분석 (A Measurement and Analysis on the Noise of 'Mugungwha' Train)

  • 신민철;왕세명;조준호;김대성
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 춘계학술대회논문집
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    • pp.394-399
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    • 2004
  • Train is one of the most famous and convenient transporting ways. However, the noise problem caused by the train hinders people from living in a silent environment. Furthermore, this problem is related with the environmental rights of people nearby the railroad. The estimation of train noise is the pre-research of train noise reduction. This research is about measurement and analysis of train noise which can be a base-study about the estimation of train n(lise. The noise of ‘Mugungwha’ train, the most frequently used train in Korea, is the main object in this measurement and analysis. The characteristics of the train noise were evident in the criteria of height, distance and velocity. Furthermore, the noise differences between locomotive and passenger coach were observable.

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축소모형 실험을 이용한 전기적 잡음에 관한연구 (The Study on an Electric Noise Effect using Physical Scale Modeling)

  • 윤점동;송영수;소경묵
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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    • pp.297-302
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    • 2007
  • Recently, electrical resistivity survey is used in the various fields and applied to urban area with many electrical noises. Therefor it's necessary to observe the electrical noise effect of the geological structure. The physical scale modeling was conducted for measuring the electric noise effect of the two geological models at various distances, depths and diameters of the electric noise objects. The results are as following. 1. When conductive noise object was vertical to the strike of geological structure and moved to the strike direction, the effect of conductive noise object at various separated distances to the measurement line was disappeared at a half distance measurement line length regardless of electrode arrays. 2. When conductive noise object was vertical to the strike of geological structure and moved to the strike direction, the effect of conductive noise object at various depths was disappeared at 4unit apart from the measurement line regardless of electrode arrays. 3. When conductive noise object was vertical to the strike of geological structure and moved to the strike direction, the effect of conductive noise object at various diameters was disappeared at 4unit apart from the measurement line regardless of electrode arrays.

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A Fault Detection and Exclusion Algorithm using Particle Filters for non-Gaussian GNSS Measurement Noise

  • Yun, Young-Sun;Kim, Do-Yoon;Kee, Chang-Don
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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    • pp.255-260
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    • 2006
  • Safety-critical navigation systems have to provide 'reliable' position solutions, i.e., they must detect and exclude measurement or system faults and estimate the uncertainty of the solution. To obtain more accurate and reliable navigation systems, various filtering methods have been employed to reduce measurement noise level, or integrate sensors, such as global navigation satellite system/inertial navigation system (GNSS/INS) integration. Recently, particle filters have attracted attention, because they can deal with nonlinear/non-Gaussian systems. In most GNSS applications, the GNSS measurement noise is assumed to follow a Gaussian distribution, but this is not true. Therefore, we have proposed a fault detection and exclusion method using particle filters assuming non-Gaussian measurement noise. The performance of our method was contrasted with that of conventional Kalman filter methods with an assumed Gaussian noise. Since the Kalman filters presume that measurement noise follows a Gaussian distribution, they used an overbounded standard deviation to represent the measurement noise distribution, and since the overbound standard deviations were too conservative compared to the actual distributions, this degraded the integrity-monitoring performance of the filters. A simulation was performed to show the improvement in performance of our proposed particle filter method by not using the sigma overbounding. The results show that our method could detect smaller measurement biases and reduced the protection level by 30% versus the Kalman filter method based on an overbound sigma, which motivates us to use an actual noise model instead of the overbounding or improve the overbounding methods.

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