• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1633-1640
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• 2000

The finite element analysis (FEA) is widely used in modem structural dynamics because the performance of structure can be predicted in early stage. However, due to the difficult in determination of various uncertain parameters, it is not be easy to obtain a reliable finite element model. To overcome these difficulties, updating program of FE model is developed by consisting of pretest, correlation and updating. In correlation, it calculates modal assurance criteria, cross orthogonality, mixed orthogonality and coordinate modal assurance criteria. For the model updating, the continuum sensitivity analysis and design optimization tool (DOT) are used. The SENSUP program is developed for model updating to obtain physical parameter sensitivity. The developed program is applied to practical examples such as the base plate of HDD, BLDC spindle motor, and upper housing of induction motor. And the sensor placement for the square plate is compared using several methods.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.955-960
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• 2000

This paper evaluates the serviceability of vibration that is induced by people's walking and running when the long span hollow core slab is used. The dynamic characteristics like a natural frequency and a ramping ratio are found by impact loading test on the mock-up structures. Also, the human induced loading test output is evaluated by the various serviceability criteria. As the various serviceability criteria satisfy with this result, the vibration problem of relevant slab caused by people's behavior does not matter.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.362-369
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• 1997

In the case of a precision equipment, it requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga class semiconductor wafers. This high technology equipments require very strict environmental vibration standard in proportion to the accuracy of the manufacturing, inspecting devices. The vibration criteria of high sensitive equipment should be expressed in the form of 'exactness' and 'accuracy', because this is made basic data in the use of building structure design. This paper made a study on the specification of high sensitive equipment and proposed a contents of the specification.

• 한국소음진동공학회논문집
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• 제17권10호
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• pp.923-935
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• 2007

In general, deflection limit criteria of bridge design specifications would have been considered based on the static serviceability and structural stability. Dynamic serviceability induced from bridge vibration, as a comfort limit, actually has not been included in the criteria. Thus, it is necessary for dynamic serviceability to be considered in bridge vibration problems and for comfort limit on vibration to be needed for evaluating dynamic serviceability of bridges. In this paper, comfort limits of bridge structures considering the time duration exposed by vibration were examined with frequency and time dependent comfort limits, and they were evaluated by using the vibration signals measured from the existing bridges. Therefore, it is resulted that the time-dependent comfort limit considering the duration of vibration is an efficient estimate for evaluating dynamic serviceability of bridges.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.306-311
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• 2012

A reactor vessel internals comprehensive vibration assessment program (RVI CVAP) of an advanced power reactor 1400 (APR1400) is being performed as a non-prototype category-2 type of reactor based on the US Nuclear Regulatory Commission Regulatory Guide (NRC RG) 1.20. The aim of this paper is to present the results of structural response analysis and measuring locations of a upper guide structure (UGS) assembly of the APR1400 reactor. The analysis results of the UGS assembly results show that meet the specified integrity levels of the design acceptance criteria. Also, the measuring locations are set by the analysis results of the UGS assembly and selection criteria of measuring locations prior to this study. These analysis results and measuring locations will be used as fundamental materials to design a measurement system for the APR1400 RVI CVAP.

• International Journal of Control, Automation, and Systems
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• 제6권6호
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• pp.818-827
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• 2008

In this paper, we propose a new noise estimation and reduction algorithm for stationary and nonstationary noisy environments. This approach uses an algorithm that classifies the speech and noise signal contributions in time-frequency bins. It relies on the ratio of the normalized standard deviation of the noisy power spectrum in time-frequency bins to its average. If the ratio is greater than an adaptive estimator, speech is considered to be present. The propose method uses an auto control parameter for an adaptive estimator to work well in highly nonstationary noisy environments. The auto control parameter is controlled by a linear function using a posteriori signal to noise ratio(SNR) according to the increase or the decrease of the noise level. The estimated clean speech power spectrum is obtained by a modified gain function and the updated noisy power spectrum of the time-frequency bin. This new algorithm has the advantages of much more simplicity and light computational load for estimating the stationary and nonstationary noise environments. The proposed algorithm is superior to conventional methods. To evaluate the algorithm's performance, we test it using the NOIZEUS database, and use the segment signal-to-noise ratio(SNR) and ITU-T P.835 as evaluation criteria.

• KIEAE Journal
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• 제7권1호
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• pp.57-64
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• 2007

This study aims to propose appropriate evaluating method of noise emission from water supply and drain installations in apartment bathroom. The measurement procedure of water installations noise in apartment bathroom were established, so it is necessary to provide the evaluating method and criteria to improve the sound insulation performance of the apartment and to reduce the apartment dweller's unsatisfaction with the noise. Thus, this study reviewed the standards and evaluating methods about the water supply and drain installations noise of many other country. After measuring the noise emission from the installations in many apartment bathroom, The noise were evaluated dB(A), N, NC index, To induce the appropriate method, the coefficient of the correlation among the evaluated numbers were analyzed. As a result, the dB(A) method is most easy to evaluating and very high correlated with N and N index, So the dB(A) method is suitable to be adopted KS evaluating procedure of noise emission from water installations in apartment bathroom.

• 한국소음진동공학회논문집
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• 제21권10호
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• pp.883-889
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• 2011

The brand sound of vehicle diesel engine is recently one of the important advantage strategies in the automotive company. Because various noise components masked under high frequency level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on vehicle sounds and noises. In particular, the interior sound quality has been one of research fields that can give high quality feature to vehicle products. Vehicle interior noise above 500 Hz is usually controlled by sound package parts. The materials and geometries of sound package parts directly affect on this high frequency noise. This paper describes the sound quality evaluation method for the vehicle diesel engine noise to establish objective criteria for sound quality assessment. Considering the sensitivity of human hearing to impulsive sounds such as diesel noise, the human auditory mechanism was simulated by introducing temporal masking in the time domain. Furthermore, each of the human auditory organs was simulated by computer codes, providing reasonable analytical explanations of typical human hearing responses to diesel noise. This method finally provides the sound quality index of vehicle diesel engine noise that includes high frequency intermittent offensive sounds caused by impacting excitations of combustion and piston slap.

• 한국산업보건학회지
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• 제30권2호
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• pp.174-184
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• 2020

Objectives: The purpose of this study was to improve the working environment by identifying the work satisfaction of the cleaning workers of the aircraft and measuring and assessing the harmful factors of the cleaning process. Methods: We asked 23 cleaning companies for questionnaires and got 100 answers from 5 companies. The A-E Airline health manager has been contacted to establish a site survey schedule. The in-flight and lounge were measured using direct reading equipment. The harmful factor to be measured are noise, dust, temperature, volatile organic compound, total airborne bacteria, and total airborne bacteria. Results: Uncomfortable positions when replacing blanket, cleaning the table, and cleaning the floor have been identified as factor that reduce work satisfaction. Noise when replacing newspapers and cleaning toilets has been identified as a factor that lowers work satisfaction. Temperature and humidity were found to reduce work satisfaction during in-flight disinfection. Measurements of aircraft cabin and lounge with direct read equipment have shown that none of the items exceed the exposure criteria. Conclusions: As a result of measuring direct-reading equipment, no items exceeded the exposure criteria for each harmful factor. A clear survey of the working environment is required based on the results, and additional research is needed using personal sample measurement.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2009년도 춘계학술대회 논문집
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• pp.29-33
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• 2009