• 음성과학
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• 제12권2호
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• pp.81-88
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• 2005

Electrodermal activity(EDA) is a bio-electric signal which occurs at the skin surface during the sweating. EDA reflects the activity of the sympathetic axis of the autonomic nervous system. EDA is associated with the eccrine sweat gland at the palmar and plamar surface. This study was aimed to characterize the relationship between EDA and auditory stimulus intensities. Acoustic stimulus used in this study were 500 Hz, 1 kHz, 2 kHz of narrow band noise, which were representative of speech frequencies in audible range. Stimulus intensity between 90 and 30 dB in 10 dB within dynamic range. After deriving the minimum stimulus intensity(threshold of skin potential) which elicited skin potential, and then the latency and amplitude were derived from waveform of skin potential, each latency and amplitude were compared to stimulus intensity. The waveform of skin potential were recorded stably, and the threshold of skin potential appeared nearly the hearing threshold level of the participant. The latency was decreased and the amplitude was increased according to the increase of the stimulus intensity. These results suggest that auditory evoked skin potential can be applicable to auditory assessment and audiological diagnosis tool.

• 대한기계학회논문집A
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• 제31권6호
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• pp.686-693
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• 2007

To perceive body movement, the nervous system uses multi-sensory cues such as vision, vestibular signals, and somatosensation. Among the multi-sensory modality, the previous researchers reported that the lower limb somatosensation plays an important role on maintaining postural balance. In this study, we examined the contribution of somatosensory cues to linear motion perception by measuring the detection threshold of the direction of linear motion with and without lower limb somatosensory constraints. Six healthy male volunteers participated in randomly ordered 33 single sinusoidal acceleration trials with the stimulus at 0.25Hz with peak magnitude ranged from 0 to 8mG. After each stimulus, subjects reported their perceived direction of motion by button press. Results showed that the reduced lower limb somatosensation significantly increased perception threshold. Without constraints, mean threshold was $0.82{\pm}0.23mG$, while it was $1.23{\pm}0.35mG$ with reduced lower limb somatosensation. The results suggest that without visual cues, perception of the movement direction strongly depends on the lower limb somatosensory information.

• 한국HCI학회논문지
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• 제1권2호
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• pp.19-26
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• 2006

가상환경 또는 실제 환경에서 정보를 제공하는 햅틱 인터페이스의 필요성이 점점 증가함에 따라 촉감을 제공하기 위한 다양한 햅틱 장치가 개발되었고 각 장치의 특성과 성능 평가를 위해 기초적인 정신(심리) 물리학적 연구가 수행 되고 있다. 본 논문에서는 여러 가지 햅틱 인터페이스 중 손가락 끝에 부착하는 형태의 새로운 공기 촉감 제시장치(PTI: Pneumatic Tactile Interface)를 제시하고 이 장치의 유용성을 입증하기 위해 localization rate, 시간 분해능, 길이 분해능, 강도의 세기 등의 심리 물리학적 실험(Psychophysical Experiment)의 수행 결과를 제시한다. 공기촉감 시스템은 50개의 출력까지 확장 가능한 공기촉감 하드웨어로 구성되어 있고 손가락 끝에 부착하는 형태로 구성하기 위해 $5{\times}5$의 배열의 디스플레이를 제작하였다. 16명의 피 실험자가 A, B 두 그룹으로 나뉘어 각각 2가지의 심리물리학 실험을 수행하였다. localization rate의 경우 9개의 다른 자극의 위치를 구별하기 위해 $3{\times}3$ 배열로 구성된 밀집된 디스플레이와 확장된 디스플레이로 측정을 수행하여 각각 58.13%, 85.9%의 localization rate를 얻을 수 있었다. 그리고 100번의 반복 실험을 통해 공기촉감제시장치의 길이 분해능을 얻을 수 있었고 자극 강도 실험의 경우, 실제의 강도가 세어짐에 따라 피 실험자들이 느끼는 강도의 척도도 증가하며, 강도가 약해지면 피 실험자들이 느끼는 강도 역시 거의 선형적으로 감소함을 알 수 있었다. 그러나 시간 분해능의 경우에는 시스템을 구성하는 밸브의 성능으로 인해 20ms 이하의 시간 분해능 측정은 제한되었다. 이러한 심리 물리학적 실험을 통하여 개발된 공기촉감 제시장치가 다양한 정보를 전달하는데 충분하다는 결론을 내릴 수 있으며, 향후 연구에서는 제안된 시스템을 사용하는 여러 가지 어플리케이션을 제시할 것이다.

• 대한의용생체공학회:의공학회지
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• 제22권3호
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• pp.269-273
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• 2001

Proper determination of pacing threshold is important for patient safety and pacemaker longevity. In general, cardiac muscle contractions caused by pacing pulses are verified by observing the morphology of surface ECG displayed on a monitor. In this study, a method of automatic pacing threshold determination based on morphological difference between intrinsic and paced ECGs was developed. First, characteristics of intrinsic ECG and paced ECG were analyzed in time and frequency domain and a proper discrimination parameter was extracted. Then, the automatic capture verification method based on the parameter was developed and applied to 23 pacemaker patients. The selected parameter was the area of ventricular depolarization wave during 80ms after pacing stimulus. It was found that the method was reliable and effective in identifying paced ECG and, thereby, determing a proper pacing threshold.

• 수산해양기술연구
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• 제52권1호
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• pp.42-47
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• 2016

This study was conducted to investigate visual threshold of nigro (Cichlasoma nigrofasciatum) on white LED light. The visual threshold was obtained by analyzing electrocardiogram (ECG) of the nigro. 5 individuals (body weight: 15.62~45.49 g; TL: 8.9~12.4 cm) were trained for lights by an electric stimulus. And then the heart rate (beats/10s) before and after switching on the light were compared. Light intensity range was from 0.00 to 226.4 lux. Average heart rate was 10.36 beats/10s in the normal condition. When the fish perceived the light, the heart rate was decreased. Visual threshold of the fish was 2.59 lux.

• 대한임상전기생리학회지
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• 제2권2호
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• pp.39-49
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• 2004

The purpose of this study were to examine the effect of high intensity, low frequency transcutaneous electrical nerve stimulation at auricular acupuncture points on experimental pain threshold measured at the wrist and to determine the changes in effect over time. Forty-two healthy adult men and women were assigned randomly to one of three treatment groups. Group 1(n=15) received TENS to appropriate auricular points for wrist, Group 2(n=12) received TENS to wrist, and Group 3(n=15) received no TENS. We measured experimental pain threshold at the wrist after an electrical stimulus during one pre-treatment and three post-treatment time periods. Group 1 and 2 showed stastically significant increase(p<0.05) in pain threshold after treatment whereas the Group 3 did not. Group 1 showed a significant increase in pain threshold than Group 2. These results suggest that high intensity, low frequency TENS applied to appropriate auricular acupuncture points can increase pain threshold.

• Restorative Dentistry and Endodontics
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• 제16권2호
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• pp.85-98
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• 1991

The aim of this study was to investigate the effect of low - power laser used in the medical field for various purposes to suppress pain responses evoked by noxious electrical or mechanical stimuli. After both inferior alveolar nerves and the left anterior digastric muscle of cats under general anesthesia were exposed, a recording electrode for the jaw opening reflex was inserted into the anterior digastric muscle. The right inferior alveolar nerve was dissected under a surgical microscope until the response of the functional single nerve could be evoked by the electrical stimulation of the dental pulp or oral mucosa. The electrical stimulus was applied with a rectangular pulse of 10 ms duration for measuring the threshold intensity of a single nerve fiber in the inferior alveolar nerve which responds to stimulation of dental pulp and oral mucosa. Then a pulse of 1 ms duration was applied for determination of conduction velocity. A noxious mechanical stimulus to the oral mucosa was applied by clamping the receptive field with an arterial clamp. The Ga-As diodide laser(wave length, 904 nm ; frequency, 1,000 Hz) was irradiated to the prepared tooth cavity, inferior alveolar nerve and oral mucosa as a pulse wave of 2 mW for 6 minutes. This was followed by a continuous wave of 15 mW for 3 minutes. The action potential of the nerve and EMG of the digastric muscle evoked by the noxious electrical stimulus and nerve response to noxious mechanical stimulus were compared at intervals of before, immediately after, and at 5, 10, 20, 40, 60 minutes after laser irradiation. The results were as follows: The conduction velocity of the intrapulpal $A{\delta}$- nerve fiber recorded from the inferior alveolar nerve before irradiation had a mean value of $6.68{\pm}2.07m/sec$. The laser irradiation did not affect the conduction velocity of the AS - nerve fiber and did not change the threshold intensity or amplitude of the action potential either. The EMG of the digastric muscle evoked by noxious electrical stimulation to the tooth was not changed by the laser irradiation, whether in latency, threshold intensity or amplitude. The laser irradiated to the receptive field of the oral mucosa which was subjected to noxious stimuli did not affect the amplitude of the action potential or the frequency either.

• 대한의생명과학회지
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• 제4권1호
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• pp.35-42
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• 1998

치료목적으로 채취한 사람 복수에서 C반응성 단백질 (CRP)을 분리 정제하여 사람 대식세포 탐식활성에 미치는 영향에 대하여 연구하였다. CRP는 p-diazonium phenyl-phosphoryl choline 혹은 C-polysaccharide coupled sepharose 4B와 hydroxylapatite affinity chromatography법으로 분리 정제 시켰다. 대식 세포는 ficoll hypaque 밀도 원심 구배법으로 분리시킨 다음 부착법으로 정제시키고 탐식 시험을 이용하여 확인하였다. CRP가 대식 세포의 시험 관내 미생물 탐식 활성에 미치는 영향은 촉진 혹은 억제시키는 경향을 보였다. 즉, CRP와 대식세포 미생물 탐식능과의 관계는 반응시킨 시간, 반응계에 가해준 CRP량, 미생물ㆍ탐식세포 및 CRP상호간 반응시킨 순서에 따라서 다르게 나타났다. 대식세포의 시험관내 탐식활성에 미치는 CRP 자극의 특성은 한계자극 특성을 보였다.

• 한국전문물리치료학회지
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• 제4권1호
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• pp.87-94
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• 1997

The purposes of this study were 1) to determine the changes between pre-treatment and post-treatment of four groups of 15 persons each and 2) to compare the effect of conventional transcutaneous electrical nerve stimulation(TENS) and laser at auricular acupuncture points on experimental pain threshold measured at the wrist. Sixty healthy adult men and women(M:32, F:28), aged 20 to 28 years, were assigned randomly to one of four groups. Group 1 received TENS to the appropriate auricular point for wrist pain, Group 2 received laser to the appropriate auricular point for wrist pain, Group 3 received placebo TENS to the appropriate auricular point for wrist pain, Group 4 received no treatment and served as controls. Experimental pain threshold at the wrist was determined with a painful electrical stimulus before and 20 minutes after ear stimulation. Group 1 was the only group that showed a stastically significant increase (p<0.05) in pain threshold after treatment whereas the Group 2,3 and 4 did not. These results suggest that TENS has the capability to higher pain threshold but laser does not.

• 한국의류산업학회지
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• 제21권1호
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• pp.88-95
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• 2019

The purpose of this study was to figure out the various characteristics of the thickness sensation among elements of tactile sensation using psychophysical method. Firstly, panel screening was processed to select sensitive thickness panel using the triangle test. As a result of discriminating the paper thickness difference from 1 to 4 pieces, the female students perceived the thickness difference more sensitively than the male students (p<.05). Secondly, JND (Just Noticeable Difference) was obtained at percentage of stimulus detection rate in order to detect the degree of thickness difference by psychophysical method. It was found that the difference threshold of the entire group was about 0.125mm, with male group being about 0.178mm and female group being about 0.095mm. Thirdly, Weber's law was used to find the minimum discrimination difference between the stimuli. The experiments were conducted by increasing the paper's base thickness from 1.950mm to 1.330mm, and it was found that the difference tendency increased when the size of the basic stimulus increased. At this time, the minimum discrimination difference increased, but the Weber' fraction was not proportional to the magnitude of the stimulus. The significance of this study was that sensory evaluation was applied to research in the fields of clothing science and it seems effective to further screen and train sensitive students as material discrimination experts.