• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.439-440
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• 2008

Five floor coverings were tested with three different types of floor structures in the standard test building in order to evaluate the effectiveness of the floor impact sound reduction. The level of floor impact sound reduction is influenced by not only the types of floor coverings but interrelationship between the floor coverings and floor structures. From the tests, it was found that floor coverings were effective in reducing the floor impact sound using the light impact source. In addition, proper mixtures of the floor structure and the floor covering have shown effectiveness to a certain extent in reducing the floor impact sound using the heavy impact source.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.131-136
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• 2004

Impact sounds, such as those created by footsteps, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The character and level of impact noise generated depends on the object striking the floor, on the basic structure of the floor, and on the floor covering. This study base on the evaluate of isolation performance of impact sound according to the impact noise reduction methods. Reduction methods consist of four ways. First way is increase thickness of bare floor and other ways are using the soft coverings on the floor and ceiling assembles. Last way is make floating floor with shock absorbing materials.

• 한국소음진동공학회논문집
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• 제14권9호
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• pp.811-818
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• 2004

Impact sounds, such as those created by footsteps, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The character and level of impact noise generated depends on the object striking the floor, on the basic structure of the floor, and on the floor covering. This study base on the evaluate of isolation performance of impact sound according to the impact noise reduction methods. Reduction methods consist of four ways. First way is increase thickness of bare floor and other ways are using the soft coverings on the floor and ceiling assembles. Last way is make floating floor with shock absorbing materials.

• 보건의료산업학회지
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• 제8권3호
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• pp.1-11
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• 2014

The present study aimed to survey doctors working in five university hospitals about internal customer satisfaction and organization commitment level in order to identify casual relationships through structure equations. According to the analysis, organization management had the biggest impact on internal customer satisfaction level, and the sooner the factor was named personnel, leadership, job, and compensation, the bigger the impact it had on the level. The research model was generally found to be good in terms of goodness of fit, considering the value of $x^2$ calculated as 103.314, the degrees of freedom of 38, GFI 0.924, AGFT 0.868, NFI 0.888, CFI 0.925, and RMSEA 0.086. In conclusion, the internal customer satisfaction level of doctors was significantly proportionate to organization commitment by means of their general satisfaction level, while also being directly proportionate to organization commitment (p<0.05). Meanwhile, statistical significance could not be found when measuring the effects of the doctors' basic characteristics on the levels of internal customer satisfaction and general satisfaction in hospitals.

• 한국시스템다이내믹스연구
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• 제16권1호
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• pp.53-74
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• 2015

The purpose of this paper is to simulate public trust on nuclear regulation policy. The first of all, public trust variables and the model were developed and analysed by system dynamic method. The model are consisted of the operator safety culture level, regulatory competence levels, the public satisfaction and public trust level. The scenario is made up three type which base scenario, the system operator's safety culture level and accident event level. First. the simulation results of standard scenario shows that rapidly declining public satisfaction and trust level of the national safety after Japan's nuclear accident in November 2011. Second, operator safety culture level and simulated divided into three levels. The results showed that a greater impact on the public satisfaction if bad than good case. Finally, the size of the accident was simulated divided into three levels levels(no accident, medium, serious accidents). the results showed a weak effect against the regulatory capacity and safety performance levels but showed a significant impact on public satisfaction and confidence level.

• 한국소음진동공학회논문집
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• 제20권1호
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• pp.66-73
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• 2010

Vehicles experience the impact due to harsh road conditions. Contact with a barrier on a road induces vehicles to vibrate, which brings about an impact sound. The attenuation of the impact sound is an important issue since passengers may complain about the impact noise. However, the perfect removal of impact noise is not possible as most of impact noise is caused by external conditions. It is thus necessary to make vehicles to possess more desirable sound quality characteristic of impact sound. More research is needed on objective attributes of impact sound; it is not a simple matter since impact noise is transient in nature and has a high level of sound at an instantaneous moment. A new objective attribute of impact noise is designed by using wavelet transform. Wavelet transform is appropriate for the analysis of transient signals such as impact noise. The usefulness of new objective attribute, which is a sound metric, is examined by comparison with the mean subjective rating for real impact noise of passenger cars. The new sound metric has better correlation with the mean subjective rating than already existing sound metrics

• Journal of Astronomy and Space Sciences
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• 제23권3호
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• pp.199-208
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• 2006

The terrestrial impact cratering record recently has been examined in the time domain by Chang & Moon (2005). It was found that the ${\sim}26$ Myr periodicity in the impact cratering rate exists over the last ${\sim}250$ Myrs. Such a periodicity can be found regardless of the lower limit of the diameter up to D ${\sim}35km$. It immediately called pros and cons. The aim of this paper is two-fold: (1) to test if reported periodicities can be obtained with an independent method, (2) to see, as attempted earlier, if the phase is modulated. To achieve these goals we employ the time/frequency analysis and for the first time apply this method to the terrestrial impact cratering records. We have confirmed that without exceptions noticeable peaks appear around ${\sim}25$ Myr, corresponding to a frequency of ${\sim}0.04(Myr)^{-1}$. We also find periodicities in the data base including small impact craters, which are longer. Though the time/frequency analysis allows us to observe directly phase variations, we cannot find any indications of such changes. Instead, modes display slow variations of power in time. The time/frequency analysis shows a nonstationary behavior of the modes. The power can grow from just above the noise level and then decrease back to its initial level in a time of order of 10 Myrs.

• Educational Technology International
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• 제7권1호
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• pp.59-79
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• 2006

The purpose of this study is to measure the impact of motivation on academic achievement and satisfaction of adult learners in an e-Learning environment, and to come up with strategies to improve the effectiveness of e-Learning for adult learners. In order to find answer, devices were developed, tested for validity and reliability, and use for testing variables for 289 adult learners. To measure the impact of achievement motivation on learning in job training, a multiple regression analysis was performed. The analysis results show that achievement motivation has an impact on academic achievement with significance level .001, but does not have an impact on a learner's satisfaction. Further analyses on the subcategories of achievement motivation show that individual-oriented motivation affects achievement with significance level of .001, while social-oriented motivation does not. From this finding, some strategies to boost individual-oriented motivation are suggested to enhance effectiveness of job training in e-Learning environment. Further strategies to boost individual-oriented motivation should be developed by studying various aspects of e-Learning such as learning environments, learning culture, learning modes and methods, and evaluation.

• 한국구조물진단유지관리공학회 논문집
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• 제21권4호
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• pp.69-79
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• 2017

표준 중량 충격원의 실제 충격원 재현성에 대한 논란이 있음에도 현재 기준에서는 뱅머신 방식만 사용하고 있다. 현행 기준의 평가방법 및 등급 기준이 충격원 특성을 고려하지 못하고 있어 충격원의 선택에 따라 바닥충격음 차단 성능 등급에 차이가 발생하기 때문이다. 본 연구는 충격원 특성 외에 바닥 진동 거동 특성을 함께 고려한 현행 기준의 바닥충격음 평가 방법 고찰을 목적으로 한다. 공동주택 mock-up 실험동에서 표준 중량 충격원과 실충격원에 대하여 바닥충격음을 측정하고 이를 이용하여 해외 평가 방법과 우리나라의 평가 방법을 비교 검토하였다. 또한 현행 바닥충격음 평가 기준의 대상 주파수 범위를 벗어나는 저주파수 대역의 음압레벨은 네텔란드의 저주파 소음 인지 곡선과 국내 연구자가 제안한 저주파 소음 기준안을 이용하여 평가하였다. 그 결과 기준 및 평가 산정 방법에 따라 성능 평가 결과가 상이하며, 바닥 진동의 지배 주파수 범위에서 모든 충격원에 대한 바닥충격음 가청 소음으로 인식하여 성가시게 느낄 가능성이 매우 크다. 현행 평가 기준의 단일수치 평가량 산정 방법은 충격원에 따라 상이한 음압레벨 스펙트럼 특성을 제대로 반영하지 못하며, 바닥의 진동 거동 지배 주파수를 포함하는 저주파수 대역의 음압레벨을 고려하지 않고 있어 바닥충격음에 대한 평가 결과와 사람의 인지 수준에 차이가 발생할 수 있다. 따라서 충격원에 따른 음압레벨의 스펙트럼 특성과 저주파수 대역의 음압레벨을 반영할 수 있도록 현행 기준의 평가 방법을 보완할 필요가 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1167-1172
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• 2007

This study investigates human floor impact sounds; not only the children's jumping and running represented by heavy-weight impact source such as bang machine and impact ball but also the high-heel walking and the light weight object dropping represented by tapping machine in the standard measurements. However, due to reliability problems as a standard impactor, bang machine has not been included in the new draft of ISO 10140 Part 3: Measurement of impact sound insulation. Therefore, the procedure to convert the floor impact sound level of the bang machine into that of the impact ball has been demanded because the bang machine has been only the standard heavy-weight standard impact source and much of its data has been collected, This study indicates that the use of impact ball is reliable and that the bang machine data can be successfully converted into the impact ball data in case of box-frame type reinforced concrete structures.