• Proceedings of the ESK Conference
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• 2004.10a
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• pp.22-22
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• 2004

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.467-473
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• 2006

가상환경 또는 실제환경에서 정보를 제공하는 햅틱 인터페이스의 필요성이 점점 증가 함에 따라 촉감을 제공 하기 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) 수행 결과를 제시한다. 공기촉감 시스템은 50개의 출력까지 확장 가능한 공기촉감 하드웨어로 구성 되어있고 손가락 끝에 부착하는 형태로 구성 하기 위해 5*5의 배열의 디스플레이를 제작하였다. 16명의 피실험자가 A, B 두 그룹으로 나뉘어 각각 2가지의 심리물리학 실험을 수행하였다. localization rate의 경우 9개의 다른 자극의 위치를 구별하기 위해 3*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 약 2.6mm의 길이 분해능을 얻을 수 있었고 자극 강도 실험의 경우, 실제의 강도가 세짐에 따라 피 실험 자들이 느끼는 강도의 척도도 증가 하며, 강도가 약해 질수록 피 실험 자들이 느끼는 강도 역시 거의 선형적으로 감소함을 알 수 있었다. 그러나 시간 분해능의 경우에는 시스템을 구성하는 밸브의 성능으로 인해 20ms 이하의 시간 분해능 측정은 제한 되었다. 이러한 심리 물리학 실험을 통하여 개발된 공기촉감 제시장치가 다양한 정보를 전달하는데 충분하다는 결론을 내릴 수 있으며, 제안된 시스템을 사용하는 여러 가지 어플리케이션을 제시하였다.

• Journal of the HCI Society of Korea
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• v.1 no.2
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• pp.19-26
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• 2006

This paper presents a novel pneumatic tactile display that can deliver some useful information. The air-jet display forms 5 by 5 arrays and features air nozzles with an external diameter of 2.4mm and internal diameter of 1.5 mm. In comparison with other tactile displays such as vibrotactile, there is little concrete psychophysical data relating to pneumatic displays, a fact which hinders their adoption. This paper addresses this challenge, and presents brief psychophysical studies examining localization rate, the two point threshold, stimulus intensity and the temporal threshold of cues produced by pneumatic air jets. Two groups of subjects were used in these studies, subsequently termed groups A and B. Both were comprised of eight participants. In the case of localization study we obtained 58.13% and 85.9% of localization rates each for dense display and sparse display. Two-points threshold test showed the length of gap between two air-jet stimuli which subjects can detect. However, it was formidable to find out precise temporal resolution of PTI owing to the limitation of capability of the pneumatic valves. Lastly, the results of stimulus intensity study suggest that by varying the size of a pneumatically created tactile stimulus, we can effectively vary its perceived magnitude.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.22 no.2
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• pp.63-71
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• 2004

제품에 대한 사용자의 주관적인 느낌을 파악하고 감성적 만족도를 측정하기 위해서는 주로설문지 등을 이용한 심물리적 스케일(Psychophysical scales) 방법이 주로 이용되어 왔다(Han et al., 2000). 그러나 사용자에게 주관적인 선호도를 점수로 표현하게 하는 심물리적 평가 방법은 몇 가지 문제점을 가지고 있다.

• Journal of the Ergonomics Society of Korea
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• v.25 no.1
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• pp.7-16
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.559-560
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• 2006

• Proceedings of the KOSOMBE Conference
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• v.1991 no.05
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• pp.18-21
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• 1991

In this paper, the effect of background grey levels on the visual perception of target image displayed on CRT monitor has been investigated. The purpose of this study is to investigate the efficacy of CRT monitor as a display medium of image information especially in medical imaging field. Three sets of experiments have been performed in this study; the first was to measure the luminance response of CRT monitor and to find the best fitting equation, and the second was the psychophysical experiment measuring the threshold grey level difference between the target image and the background required for visual discrimination for various background grey levels, and the third was to develop a visual model that is predictable of the threshold grey level difference measured in the psychophysical experiment. The result of psycophysical experiment shows that the visual perception performance is significantly degraded in the range of grey levels lower than 50, which is turned out due to the low luminance change of CRT monitor in this range while human eye has been adapted to relatively bright ambient illumination.

• Journal of the Ergonomics Society of Korea
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• v.23 no.3
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• pp.89-99
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• 2004

A comprehensive psychophysical scaling system, multiple-modality magnitude estimation system (MMES) has been designed to measure subjective multidimensional human perception. Unlike paper-based magnitude estimation systems, the MMES has an additional auditory peripheral cue that varies with corresponding visual magnitude. As the simplest, purely psychological case, bimodal divided-attention conditions were simulated to establish the superiority of the MMES. Subjects were given brief presentations of pairs of simultaneous stimuli consisting of visual line-lengths and auditory white-noise levels. In the visual or auditory focused-attention conditions, only the line-lengths or the noise levels perceived should be reported respectively. On the other hand, in the divided-attention conditions, both the line-lengths and the noise levels should be reported. There were no significant differences among the different attention conditions. Human performance was better when the proportion of magnitude in stimulus pairs were identically presented. The additional auditory cues in the MMES improved the correlations between the magnitude of stimuli and MMES values in the divided-attention conditions.

• IE interfaces
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• v.17 no.2
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• pp.218-225
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• 2004

This study aims to investigate effect of external load and motion repetitiveness on perceived discomfort. An experiment was performed for measuring discomfort scores at varying conditions, in which external load, motion repetitiveness and arm posture were employed as experimental variables. The arm posture was controlled by shoulder flexion and abduction, and by elbow flexion. Fifteen healthy college-age students without history of musculoskeletal disorders voluntarily participated in the experiment. The results showed that the effect of external load, motion repetitiveness and shoulder posture on discomfort were statistically significant, but that elbow posture did not significantly affect discomfort ratings. The effect of external load was much larger than that of any other variables, and that of repetitiveness was second only to external load. Discomfort scores significantly increased linearly as the levels of external load and motion repetitiveness increased. This implies that although they were not fully reflected in the existing posture classification scheme such as OWAS, RULA, etc., the effect of external load and motion repetitiveness should be taken into consideration for precisely quantifying work load in industry. Based on regression analysis, equivalent values of external load and motion repetitiveness in terms of discomfort scores were provided, which would be useful for better understanding the degree of their effect on work load.

• Journal of Biomedical Engineering Research
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• v.14 no.1
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• pp.63-72
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• 1993

In this paper, the effect of background grey levels on the visual perception of target image displayed on CRT monitor has been investigated. The purpose of this study is to investigate the efficacy of CRT monitor as a display medium of image Information especially in medical imaging field. Tllree sets of experiments have been performed in this study : the first was to measure the luminance response of CRT monitor and to find the best fitting equation, and the second was the psychophysical experiment measuring the threshold grey level differences between the target image and the background required for visual discrimination (or various background grey levels, and the third was to develop a visual model that is predictable of the threshold grey level difference measured in the psychophysical experiment. The result of psycophysical experiment shows that the visual perception performance is significantly degraded in the range of grey levels lower than 50, which is turned out due to she low luminance change of CRT monitor in this range while human eye has been adapted lo relatively bright ambient illumination. And it Is also shown in the simulation study using the developed visual model that the dominant factor degrading the visual performance is the reflected light from the monitor surface by ambient light in general illumination condition.