• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.338-339
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• 2009

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.189-199
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• 1999

The revision was proposed for methods A-weighted sound pressure measurement for fans, blowers and compressors in order to apply newly developed measurement techniques to KS B 6361 established in 1987. This proposal includes modification of terminologies, revision of sound power methods for radiated sound from the body, inclusion of In-duct measurement method, and correction method for flow noise upon microphon.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.345-349
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• 2006

There has been an increasing demand for the mitigation of noise and vibration caused by KTX. One of considered noise reduction methods which is to enlarge mud-flap in gangway was selected and the replacement of all KTX mud-flaps by improved mud-flaps was completed recently. To investigate the noise characteristics of KTX with improved mud-flap, the measurement was performed. Based on the measurement results, the assessment of noise level, noise characteristics by speed and pure tone analysis for various track conditions was executed. It is shown that the use of improved mud-flap is effective to reduce the interior noise of KTX.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.709-714
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• 2008

The various computer programs are used in computer simulation of the traffic noise prediction. But the difference or problem of calculation method used for road traffic noise prediction is not exactly investigated. In this paper, Road traffic noise is predicted on the specific regions by using four prediction methods such as XPS31-133 model(France), RLS-90 model(Germany), ASJ RTN model(Japan) and FHWA model(U.S.A.), which are operated by a program named SoundPLAN, a program to predict road traffic noise. Those prediction values are compared with a measurement value. The results show that four prediction values for taraffic noise are a little different, because of various input factors according to the prediction methods.

• 전자공학회논문지
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• 제54권3호
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• pp.63-69
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• 2017

NNPS(normalized noise power spectrum)는 획득한 x선 영상에서 평판형 방사선 디텍터의 잡음 특성을 spectrum을 관찰하기 위해 측정한다. 그러나 NNPS 측정은 획득한 영상에 따라 일관적이지 못한 성질을 가지고 있어서 안정된 측정이 필요하다. 디텍터의 NNPS 측정은 표본 periodogram을 구하여 평균을 내는 방법을 사용하는데, 일반적으로 표본의 개수를 충분히 늘리면 정확하면서 안정된 값을 구할 수 있다. 본 논문에서는 periodogram과 같은 표본 spectrum의 평균으로 유한한 개수의 영상이 주어졌을 때 일관적이고 효율적인 NNPS 값을 제공 할 수 있는 두 가지 방법을 제안하고 그 성능을 비교하고 분석했다. 실제 두 종류의 방사선 디텍터로부터 획득한 x선 영상을 사용하여 제안한 방법을 실험하였으며, 주어진 영상을 사용하여 표본 spectrum의 최대 가지 수를 갖는 조합으로 NNPS를 구하고 평균을 내는 방법이 기존 방법에 비하여 안정된 NNPS 측정이 가능함을 보였다.

• 제어로봇시스템학회논문지
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• 제20권6호
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• pp.631-634
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• 2014

We propose a measurement state feedback controller for a class of nonlinear systems that have uncertain nonlinearity and sensor noise. The new design method based on the matrix inequality approach solves the measurement feedback control problem of a class of nonlinear systems. As a result, the proposed methods using a matrix inequality approach has the flexibility to apply the controller. In addition, the sensor noise can be attenuated for more generalized systems containing uncertain nonlinearities.

• 센서학회지
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• 제13권1호
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• pp.1-11
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• 2004

Due to various types of errors added to dynamic weight measurement data, proper methods to reduce measurement errors are required to produce reliable weights. To cope with parasitic types of errors in real systems, information provided by the various sensors is utilized and combined in such a way to reduce the measurement errors of load cells. In addition to four channels of load cells from a trailer, an accelerometer is used to obtain the information to compensate the error induced from vertical movement of the vehicle due to the variation of ground level. A model trailer system is run to verify the effectiveness of the proposed method to reduce noise of dynamic weight measurements. Experiments show that the processed error magnitudes of less than 20 g can be obtained for 10 Kg experimental loads.

• International Journal of Railway
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• 제6권3호
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• pp.125-130
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• 2013

Most of the test methods used for determining the acoustic performance of the noise barriers in Korean standards address the sound-proof panels but refer to noise barriers as a whole system or their in-situ performances less. Many new types of trains with different operating speeds have been developed and produced, and civil appeals against railway noise are becoming quite extensive. Considering these latest changes of circumstances, it is necessary to investigate the current standards and specifications pertaining to railway noise barriers. In this paper, criteria for the measurements and evaluations of noise barriers and sound-proof panels are examined and experimental studies are introduced. In order to suggest more efficient methods for reasonable evaluations of the noise barriers, frequency spectrums of the noise source, the power of the actual railway vehicles, are investigated and introduced.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1382-1385
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• 2007

In this paper, we study about the measuring algorithm that can implement Structural Health Monitoring (SHM) more efficiently by two measurement methods using smart sensor. Through the impedance measurement method, the damage condition of structures on wide area is monitored first, and then it changes the mode to guided wave measurement mode by mode switching algorithm when impedance measurement mode detects abnormal signals. Efficient handling of the real-time data would be available by analyzing location and shape of damage through guided wave measurement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.6-11
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• 2007

Packaged power station (PPS) is a stationary diesel engine generator set and developed for the supply of electric power to small villages, islands and factories etc. Therefore, the PPS is closely installed to residence area and sometimes cause the environmental noise problems. In this paper, environmental noise analysis was performed for the power plant with 28 sets of PPS. The initial analysis results showed the some difference between the measurement and analysis because of the inaccurate noise source data. To improve the accuracy of analysis, main noise sources were inversely estimated using the in-situ measurement data in the vicinity of PPS and steam boiler. As the results of re-analysis, the good agreement was obtained and it was concluded that the noise levels exceed the specified noise limit in residence area. In order to reduce the noise, the several methods such as geometry alteration of inlet duct, application of hybrid-type silencer and noise protection barrier were suggested and verified with the confirmed analysis model.