• 한국소음진동공학회논문집
• /
• 제19권2호
• /
• pp.176-183
• /
• 2009

The objective of this study is to prepare the plans for managing construction noise effectively and solving the popular enmity from construction noise reasonably. In order to carry out this purpose, it covers the efficient improvement plans for adjusting the construction noise regulation standard rationally and managing the automatic noise measuring system which shows the advantage for construction noise management and popular enmity solution due to construction noise. The three alternative plans of the construction noise regulation standard and the recommendation plan including the guideline for installing and managing the automatic noise measuring system are suggested consequently.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.252-256
• /
• 2001

Scattering of surface materials has been known as one of the most important aspects in evaluating the acoustics of concert halls are designed. One of the methods that can reduce the errors in estimating the reverberation time and other acoustic parameters through computer modeling is to calculate scattering coefficient of surface materials. However. so far, no objective and reliable methods measuring scattering coefficient has been suggested. In this situation, ISO has suggested the method of measuring the random-incidence scattering coefficient on surfaces in diffuse field, whereas AES has introduced a method on directional-incidence in free field. In this study, the scattering coefficients of five kinds of hemispheres (1.5, 2.0. 2.5. 3.0. 3.5cm) were measured by using the ISO method in 1：10 reverberation chamber. It was found that 3.0cm hemisphere has the highest scattering coefficient satisfying 95％ reliability.

• Safety and Health at Work
• /
• 제6권3호
• /
• pp.159-173
• /
• 2015

The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 II
• /
• pp.1356-1360
• /
• 2001

A number of calibration methods are described in ISO 16063 (revision of ISO 5347) and they may be used for special purposes. However, the use of a laser interferometer is recommended for primary calibration. This paper introduces the primary vibration calibration by measuring displacement amplitude and frequency using laser interferometry.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.296-299
• /
• 2006

This study is about correlation between WECPNL and other units such as NNI, Leq and Ldn for aircraft noise that ere measured by automatic measuring system networks for grasping the effect of aircraft noise and investigated the aircraft noise level from 2004 to 2005 nearby 10 airports in Korea. It is very important to find the relationship among the various noise units, because exchange between the results of many other nation's study can improve the assessment and mitigation study of the aircraft noise. Correlation between WECPNL and M is better than one between WECPNL and Leq and between WECPNL and Ldn, because WECPNL and NNI are based on the PNL.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.170-176
• /
• 2003

The pantograph for Korean High Speed Train was developed and had been evaluating by through "G7- R＆D for home grown high speed train technology". In this study, a relation in mechanical aspect between the train running speed and the current collecting performance of the pantograph is conducted.'for this study, a measuring system for current collecting performance and mechanical characteristics is developed and installed on the prototype Korean High Speed Train, and measurement is conducted while the train runs on the test track. The measuring system is composed of video monitoring system and telemetry & data processing unit. It monitors whether the hazard behavior in the pantograph is occurs or not, and measures acceleration and vertical contact force between the pan head and catenary. Through this study, evaluation of a mechanical vibration characteristics and trend of the pantograph and a interface performance of pantograph - catenary up to 200㎞/h train speed are facilitated.

• 한국산업융합학회 논문집
• /
• 제25권2_1호
• /
• pp.169-176
• /
• 2022

Prognostics and health management (PHM) is recently converging throughout the industry, one of the trending issue is to detect abnormal conditions at decanter centrifuge during water treatment facilities. Wastewater treatment operation produces corrosive gas which results failures on attached sensors. This scenario causes frequent sensor replacement and requires highly qualified manager's visual inspection while replacing important parts such as bearings and screws. In this paper, we propose anomaly detection by measuring the vibration of the decanter centrifuge based on the video camera images. Measuring the vibration of the screw decanter by applying the optical flow technique, the amount of movement change of the corresponding pixel is measured and fed into the LST M model. As a result, it is possible to detect the normal/warning/dangerous state based on LSTM classification. In the future work, we aim to gather more abnormal data in order to increase the further accuracy so that it can be utilized in the field of industry.

• 소음진동
• /
• 제8권5호
• /
• pp.922-928
• /
• 1998

This paper presents the automatic alignment measuring system for improving the accuracy and working time of alignment of large vertical hydraulic pump turbine. It is general practice that rotating shaft should run within acceptable vibration limit. In order to obtain better run-out data of multi-stage rotor, careful and accurate alignment approach must be established. Generally, present alignment procedure are required several iterative works and so many manpower. Therefore, the new system has been developed using a vector calculation algorithm, laser sensor and data acquisition devices. As a result of appling to actual machines, it is confirmed that manpower is saved up to an average 90%.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 춘계학술대회 논문집
• /
• pp.743-748
• /
• 2007

The important factor to evaluate the running safety of a railway vehicle would be the interaction force between wheel and rail(derailment coefficient), for which is one of important factors to check the running safety of a railway vehicle that may cause a tragic accident. Especially, a newly developed vehicle that first runs commercially requires necessarily the measurement and evaluation of derailment coefficient for securing the safety of a vehicle while measuring the derailment coefficient in view of securing running safety could be the more important factor than any other factors. In this paper, examined possibility that can forecast derailment possibility to behavior of only vibration and displacement by measuring vibration acceleration and displacement in vehicles that travel actuality rail track, and compares with data of wheel load/lateral force result.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1994년도 추계학술대회 논문집
• /
• pp.432-438
• /
• 1994

This paper describes the measuring method of vibration mode shapes by the Electronic Shearography. Shearographic interferometer has many merits in practical use, that is low sensitive to the environmental noisy, liw limit of the coherent-length and simple optical configuration etc.. In this study, we developed Michelson-type shearing interferometer provided with a phase stepping mirror and with a bias modulation mirror to quantify the vibration gradient fields. As a results of application to a simple cantilever plate vibration amplitude fields were obtained by the proper integration technique, and their exprimental results were in good agreement with those of the ESPI experiment.