• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.581-586
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• 2008

This study aims to examine the existing single rating index in terms of level reduction limit of heavy-weight floor impact sound. To achieve this goal, sounds which have same loudness according to rating methods were suggested to subjects. And followings are results. 1) The rating method of measurement frequency level average is more suitable than that of other methods which are dependent on specific frequency for rating heavy-weight floor impact sound. 2) Level average for measurement frequency of 31.5Hz - 500Hz is more correspondent to psycho-acoustic response than that of measurement frequency of 63Hz - 500Hz which is for KS F 2863-2, existing rating method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1185-1191
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• 2001

This paper discusses an experimental method for measuring the insertion loss (IL) performance of multi-layered insulations that are used in vehicles. Instead of two adjacent reverberation chambers which are generally used to measure the transmission loss (TL) of the large sound isolation materials, air-borne sound insulation tester was utilized to determine the IL and articulation index (AI) of standardized insulation materials. In comparison to reverberation chamber method, air-borne sound insulation tester method is more space-saving, more time-saving and more simple to the automotive acoustics. From the empirical results, it is found that the performances of insulation materials are closely connected with density of polyurethane foam, thickness of heavy layer, thickness of polyurethane foam, and application ratio to panel area.

• 한국소음진동공학회논문집
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• 제19권3호
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• pp.282-287
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• 2009

This study aims to examine the existing single rating index in terms of level reduction limit of heavy-weight floor impact sound. To achieve this goal, sounds which have same loudness according to rating methods were suggested to subjects. And followings are results. 1) The rating method of measurement frequency level average is more suitable than that of other methods which are dependent on specific frequency for rating heavy-weight floor impact sound. 2) Level average for measurement frequency of $31.5\;Hz{\sim}500\;Hz$ is more correspondent to psycho-acoustic response than that of measurement frequency of $63\;Hz{\sim}500\;Hz$ which is for KS F 2863-2, existing rating method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1383-1386
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• 2006

This study examines the difference of airborne sound isolation between laboratory and field test. The airborne sound isolation between adjacent dwellings in multi-family buildings is often much less than would be expected from the rated sound reduction index of the nominally-separating wall, due to structure-borne transmission of vibration at the junctions of wall. A variety of construction modifications to control such transmission have also been evaluated. This study presents a factor of the difference for flanking involving joint of wall, and shows the effect of some practical modifications that control the key flanking paths

• Journal of Oral Medicine and Pain
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• 제35권2호
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• pp.135-147
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• 2010

본 연구에서는 최근 Sato 등이 고안한 mixing ability index(MAI)를 이용하여 측두하악장애 환자 중 통증이 있는 군과 무통성 관절잡음이 있는 군을 대상으로 객관적인 저작 효율을 정상인으로 구성된 대조군과 비교하고, 주관적인 평가 방법인 설문조사법 중에서 음식섭취가능지수(Food Intake Ability Index, FIA)와 저작 능력에 대한 주관적 인식도 평가(Visual Analogue Scale, VAS)를 이용하여 저작 효율을 평가하고, 구강건강과 관련된 삶의 질을 평가하기 위해 Oral Health Impact Profile(OHIP)-49K 설문조사를 시행하였다. 각 평가 방법 간의 상관성을 알아보고, 또한 통증군에 있어서는 치료 후 통증이 감소함에 따라 저작 효율의 변화 양상을 조사하여 다음과 같은 결과를 얻었다. 1. MAI, FIA, VAS는 통증군이 정상군에 비해 통계학적으로 유의하게 감소하였으며, 관절잡음군보다도 감소하여 통증군이 정상군과 관절잡음군에 비해 저작 효율이 떨어지는 것으로 나타났다(P<0.05). 관절잡음군에서는 MAI, FIA, VAS에서 정상군과 유의한 차이를 보이지 않았다. 2. 구강건강관련 삶의 질에 대한 설문지인 OHIP-49K의 경우 정상군에 비해 통증군과 관절잡음군 모두 통계학적으로 유의하게 증가하여 구강건강과 관련한 삶의 질이 떨어지는 것으로 나타났다. 3. 전체 대상자(71명)에서 객관적 저작 능력 평가 방법인 MAI와 주관적 저작 능력 평가 방법인 FIA와 VAS간에는 서로 유의성 있는 상관관계를 보였다(P<0.01). OHIP-49K에서도 MAI를 제외하고 모두 통계학적으로 상관관계가 있는 것으로 나타났다. 4. 관절잡음군에서는 FIA와 VAS에서만 통계학적으로 상관관계가 있는 것으로 나타났으며(P<0.01), 이외의 모든 항목은 상관관계가 없는 것으로 나타났다. 5. 각 평가 방법 간의 상관성에서 FIA와 VAS는 전체 대상자, 통증군, 관절잡음군 모두에서 상관관계가 있는 것으로 나타났다. 6. 통증군에서 치료 전에 비해 치료 후 통증 감소와 함께 VAS에서는 통계학적으로 유의성 있게 증가 하였다(P<0.05). 반면에 MAI에 있어서는 저작 효율이 증가하는 경향을 보였으나 통계학적 유의성은 없었다. 또한 FIA, OHIP-49K에서도 치료 전과 후 통증 감소에 따른 변화는 없는 것으로 나타났다. 이번 연구를 통하여 측두하악장애 환자에서 저작 효율을 감소시키는 주요인은 통증이며, 관절잡음은 저작 효율을 감소시키는 요인은 아니지만 삶의 질을 저하시키는 한 요인으로 작용한다는 것을 알 수 있었다. 따라서 측두하악장애 환자에서 저작 효율을 개선시키기 위해서는 우선적으로 통증을 치료하는 것이 가장 중요하며, 삶의 질을 향상시키기 위해서는 통증뿐만 아니라 관절잡음에 대한 관리도 필요할 것으로 사료된다.

• 한국소음진동공학회논문집
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• 제16권9호
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• pp.897-903
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• 2006

The reduction of the vehicle interior noise has been the main interest of noise and vibration harshness (NVH) engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the heating, ventilation and air conditioning (HVAC) system sound among the vehicle interior noise has been reflected sensitively in psychoacoustics view point. Even though the HVAC noise is not louder than overall noise level, it clearly affects subjective perception to drivers in the way of making to be nervous or annoyed. Therefore, these days a vehicle engineer takes aim at developing sound quality as well as reduction of noise. In this paper, we acquired noises in the HVAC from many vehicles. Through the objective and subjective sound quality (SQ) evaluation with acquiring noises recorded by the vehicle HVAC system, the simple and multiple regression models were obtained for the subjective evaluation 'Pleasant' using the semantic differential method (SDM). The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Furthermore, the neural network (NN) model were obtained using three inputs(loudness, sharpness and roughness) of the SQ metrics and one output(subjective 'Pleasant'). Because human's perception is very complex and hard to estimate their pattern, we used NN model. The estimated models were compared with correlations between output indexes of SQ and hearing test results for verification data 'Pleasant'. As a result of application of the SQ indexes, the NN model was shown with the largest correlation of SQ indexes and we found possibilities to predict the SQ metrics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.909-917
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• 2007

Recently the trend of automobile industry is that IQS evaluation index against a sensitivity quality is increasing. To reduce rattle noise due to speaker sound at low frequencies, it is required the advanced investigation of a package tray panel and a door module panel. This paper optimized the design parameters of package tray panel according to the theoretical background about robust design and suggested the design guideline for resonance avoidance and the reduction of vibrational sensitivity considering the excitation frequency of woofer speaker. In addition, it is suggested the design guideline of a door module panel through the sensitivity analysis in case of the speaker excitation. Finally, the design factor analysis of the quality deviation of a mother-car will make it possible to guarantee the stable characteristics of vehicle vibration in the early stage of vehicle development. These improvements can lead to shortening the time needed to develop better vehicles.

• 한국소음진동공학회논문집
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• 제17권8호
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• pp.673-682
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• 2007

Recently the trend of automobile industry is that IQS evaluation index against a sensitivity quality is increasing. To reduce rattle noise due to speaker sound at low frequencies, it is required the advanced technology analysis process of body structure. This paper optimized the design parameters of package tray panel according to the theoretical background about robust design and suggested the design guideline for resonance avoidance and the reduction of vibrational sensitivity considering the excitation frequency of woofer speaker. And this paper described the design process of a door module panel through the sensitivity analysis in case of the door speaker excitation. Finally, the analysis of the quality deviation using mother car is suggested to guarantee the stable characteristics of vehicle vibration in the early stage of vehicle development. These improvements can lead to shortening the time needed to develop better vehicles.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1871-1876
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• 2010

사람이 소리를 듣는 것은 다분히 감정적이고 주관적으로 이루어진다. 따라서 소음 측정의 척도로 주로 사용되는 dB(A)와 같은 청감을 고려한 수치로 표현하기 어렵기 때문에 때와 장소, 차량에 따라 주관적이고 사람의 감정에 맞는 주관적 척도가 요구된다. 즉, 평가하고자 하는 음질인자 항목들은 독립적 관계가 아닌 서로 상관관계의 특성을 고려하여 음질 평가를 수행해야 한다. 그러므로 인간의 청감에 가깝고 정확한 음질 평가를 위해서는 음질인자 별 다변량 분석이 필요하다. 본 연구에서는 차량 주행 소음을 대상으로 특성인자간 상관관계를 고려해 시스템을 분석할 수 있는 마할라노비스 거리(Mahalanobis distance,MD)를 통해 음질 인덱스를 구축하고자 한다.

• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.67-78
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• 1996

This study was performed to compare the TMJ sounds by means of vibration-related items by Sonopak such as integral, high integral, above 300/(0-300) ratio, peak amplitude, peak frequency and median frequency before and after occlusa1 splint therapy as well as counselling, physical modalities. For this study 22 patients with craniomandibular disorders (CMDs) were selected and examined by routine diagnostic procedure for CMDs including Transcranial and Panoramic radiographs and were classified into 3 CMDs subgroups : disc displacement with reduction, disc displacement without reduction, and degenerative joint disease. Visual analogue scale (VAS) about joint sound was recorded during treatment period and VAS treatment index (VAS Ti) was calculated from the VAS data and treatment duration. The author evaluated and compared treatment results by several parmeters such as symptom duration, timing of joint sound, parafunctional habits, trauma, and diagnostic classification. The obtained results were as follows : 1. Before the treatment, the highest value of peak amplitude was observed in disc displacement with reduction group and value of median frequency was highest in degenerative joint disease group. In addition the highest values of peak frequency and ratio ware observed in degenerative joint disease group, though they were not significant. Furthermore the lowest value of high integral was observed in disc displacement without reduction group and though it was not significant, value of integral was lowest in that group. 2. Among 3CMDs subgroups disc displacement with reduction group showed the significantly decreased value of high integral and degenerative joint disease group had the significantly decreased value of integral after conservative treatment including occlusal splint therapy. Conclusively conservative treatment including occlusal splint therapy vay be effective in the treatment of CMDs including TMJ sound. 3. Fair prognosis for conservative treatment was observed in acute group under 6 months than chronic group, 6 months over in symptom duration but there was no statistical difference. The result for conservative treatment was observed slightly poor in subjects with bruxism, clenching, unilateral chewing habit and trauma history but there were no statistical differences.