• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.769-770
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• 2011

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.88-93
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• 2006

대부분의 입체 영상물은 단지 화면을 입체로 보여주는 것만이 목적이다. 그러나 만약 입체 영상으로 표현된 가상 물체를 손가락을 뻗어 실제로 만져볼 수 있다면 현실감은 더욱 증가할 것이다. 본 연구에서는 입체영상 장치로 만든 가상 비누방울들을 실제 자기 손가락으로 터뜨리는 듯한 느낌을 가질 수 있도록 해주는 가상 현실 게임 시스템을 만들었다. 이 때 두 개의 위치/방향 센서를 이용하여 손가락 끝과 머리의 움직임을 추적하여 가상 공간과 현실 공간의 두 좌표계를 서로 일치시켜 볼 수 있도록 하였으며, 자체 제작한 진동촉각 장치를 이용하여 비누방울을 터뜨릴 때 손가락에 약한 진동 촉감을 제공하여 실제로 자신이 비누방울을 터뜨리는 듯한 느낌을 갖도록 하였다. 이러한 시도를 통해 입체영상 기술을 이용한 가상현실 게임에서의 진동촉각 장치의 활용 가능성을 확인하였다.

• 한국산학기술학회논문지
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• 제20권12호
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• pp.645-651
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• 2019

본 연구는 전방머리자세와 턱관절 장애 및 정량적 턱관절의 체성감각의 상관관계를 알아보고자 연구를 진행하였다. 본 연구는 대상자 선정요구를 충족한 62명의 대상자(22.15±2.56세)을 대상으로 전방머리자세에 대한 중재 후 전방머리 자세 변화에 따른 턱관절 기능 및 체성감각의 상관관계를 분석하였다. 전방머리자세에 대한 중재는 바이오피드백 훈련을 실시하였으며, 주 3회 총 4주간 총 12회 진행되었다. 전방머리자세를 평가하기 위하여 머리-척추각을 검사하였으며, 턱관절 기능은 입 벌림과 좌, 우측 치우침을 검사 하였고, 체성감각의 변화를 확인하기 위하여 진동역치감각을 측정하였다. 연구결과 머리 척추각의 변화에 따른 턱관절 기능(p<0.001) 및 체성감각(p<0.001)의 변화는 모두 유의한 상관관계를 보였다. 연구 결과 전방머리자세와 턱관절 기능 및 체성감각에 유의한 상관관계를 보였으며, 본 연구를 기반으로 턱관절 장애로 고통 받고 있는 환자들에게 턱관절 치료에 새로운 패러다임을 제공 할 수 있을 것이며, 향후 턱관절의 치료에 대한 기초 자료로 제공 될 수 있을 것이다.

• 한국지반공학회논문집
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• 제21권2호
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• pp.105-111
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• 2005

본 연구에서는 경사말뚝과 수직말뚝의 정적/동적 거동을 분석하고, 경사말뚝의 내진성능을 향상시키기 위한 보강방법을 제안하기 위하여 진동대 모형시험을 수행하였다. 첫 번째로 정적 횡방향 재하시험을 수행하여 정적 횡방향 하중을 받는 경사말뚝과 수직말뚝의 거동을 비교분석하였으며, 두 번째로 진동대 모형실험을 수행하여 말뚝머리에서 발생하는 축력과 침모멘트를 분석하여 지진하중에 대한 경사말뚝의 취약성을 확인하였다. 마지막으로 지진시 경사말뚝의 내진성능을 향상시킬 수 있는 보강기법을 제안하고 진동대 모형실험을 통하여 그 유효성을 확인하였다. 본 연구에서 경사말뚝의 내진 보강기법으로 말뚝머리와 상부갑판을 연결할 때 고정연결 대신 연성이 큰 고무와 힌지를 이용한 연결조건을 제안하였으며, 경사말뚝의 경사각이 수직 대 수평비가8:3 일 때 지진하중에 의해 경사말뚝에서 최소의 부재력이 발생하는 것을 확인하였다.

• 한국소음진동공학회논문집
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• 제18권9호
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• pp.905-912
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• 2008

Notion sickness is well known to be caused by long time exposure to the very low frequency motion in the multiple axes of human body Since the vestibular system for the perception of low frequency motion is located in the head, accurate measurement of 6 degree of freedom head motion is of great importance. In this study, the measurement system consisting of a safety helmet and 9 translational accelerometers was constructed for the estimation of 3 translational and 3 rotational motions of human head. Since estimation errors of 3 rotational components can be significantly magnified even by small offset of the sensitivity axis from the geometric center of an accelerometer, accurate measurement of sensitivity axis must be preceded. The method for accurate estimation of the offset was proposed, and the effect of offset on the estimation of angular acceleration was investigated.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.448-457
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• 2008

A principal components analysis (PCA) of the median-plane head-related impulse responses (HRIRs) in the CIPIC HRTF database reveals that the individual HRIRs in the median plane can be adequately reconstructed by a linear combination of 12 orthonormal basis functions. These basis functions can be used to model arbitrary median-plane HRIRs, which are not included in the process to obtain the basis functions. Memory size can be reduced up to 5-fold depending on the number of HRIRs to be modeled. To clarify whether these basis functions can be used to model other set of arbitrary median plane HRIRs, a numerical error analysis for modeling and a series of subjective listening tests were carried out using the measured and modeled HRIRs. The results showed that the set of individual HRIRs in the median plane, which were measured in our lab using different measurement conditions, techniques, and source positions, can be modeled with reasonable accuracy. All subjects, involved in the subjective listening test, reported not only the accurate vertical perception but also the front-back discrimination with the modeled HRIRs based on 12 basis functions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.103-107
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• 2009

Because individual HRTFs (Head-Related Transfer Functions) vary from a person to a person, a HRTF database has been measured by researchers to investigate the inter-subject variation, and to generate high fidelity virtual sound image. Individual HRTFs not only vary between subjects but also vary due to wearing clothes and glasses in daily life. However, influence of different dressing condition on the measured HRTF was not sufficiently investigated. To quantify the effect of wearing clothes and glasses, dummy's HRTF is measured in an anechoic chamber with various dressing condition, and is evaluated in the sense of spectral distortion. HRTFs are measured both in the median plane and in the horizontal plane. In the median plane, under 6kHz, effect of different wearing clothes and glasses is negligible. Over 6kHz, however, effect of clothing distorts HRTF about 6dB in the sense of spectral distortion. Moreover, at high frequencies, effect of glasses is no longer negligible. In the horizontal plane, at some azimuths, even additional light cloth over the dummy can change the spectrum of HRTF (6dB spectral distortion) especially when sound source is at contralateral positions. Therefore, HRTF measurement with different wearing conditions can broaden the capability of HRTF customization whose technique utilizes a HRTF database.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.920-927
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• 2008

This study deals with modeling of Head-Related Transfer Functions (HRTFs) using Principal Components Analysis (PCA) in the time and frequency domains. Four PCA models based on Head-Related Impulse Responses (HRIRs), complex-valued HRTFs, augmented HRTFs, and log-magnitudes of HRTFs are investigated. The objective of this study is to compare modeling performances of the PCA models in the least-squares sense and to show the theoretical relationship between the PCA models. In terms of the number of principal components needed for modeling, the PCA model based on HRIR or augmented HRTFs showed more efficient modeling performance than the PCA model based on complex-valued HRTFs. The PCA model based on HRIRs in the time domain and that based on augmented HRTFs in the frequency domain are shown to be theoretically equivalent. Modeling performance of the PCA model based on log-magnitudes of HRTFs cannot be compared with that of other PCA models because the PCA model deals with log-scaled magnitude components only, whereas the other PCA models consider both magnitude and phase components in linear scale.

• 한국소음진동공학회논문집
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• 제19권12호
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• pp.1260-1268
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• 2009

Three methods(the stepped sine method, the statistical method(random excitation method) and the maximum-length sequence(MLS) method) for head-related transfer functions(HRTFs) are experimentally compared in view point of accuracy and efficiency. First, the stepped sine method has high signal-to-noise ratio, but low efficiency. Second, the statistical method is fast measurement speed, but weak to noise than the other methods. Finally, the MLS method shows both good efficiency and high signal-to-noise ratio, but it needs additional software or equipment such as MLS signal generator. For comparison of measurement accuracy, HRTFs of KEMAR dummy are measured for various azimuths and elevations. Error norms for magnitude and phase of HRTFs are defined and calculated for the measured HRTFs. The calculated error norms show that the methods give similar results in magnitude and phase except a little phase difference in the MLS method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.621-626
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• 2002

Two problems in the measurement of 6-DOF head vibration in very low frequency range were investigated in this study. One is how much error was involved in the estimation of three rotational and three translational motion at any specified point from measured 6 translational accelerations. The other is quantitative and qualitative influence of gravity on DC and AC component of the estimated accelerations in 6 degree of freedom, which were derived from pick-ups fixed on a helmet. In the study the effect of nonlinear terms on the estimation of 6 degree of freedom accelerations was negligible but gravity effect must be considered carefully.