• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1992년도 춘계학술대회
• /
• pp.55-57
• /
• 1992

Image display is the last step of imaging chain in which the diagnostic information is transformed into perceivable intensities and transformed to observer's eye-brain system. In this process, a certain part of information may be efficiently transfered and another part may be inefficiently transfered leading to information loss. In this study, the visual perceptual properties of image display on CRT monitor has been investigated. Psychophysical experiment of target image detection has been performed using CRT monitor for various background grey levels, and the threshold difference grey levels required for visual discrimination have been predicted by computer simulation with visual model.

• Journal of Information Display
• /
• 제5권3호
• /
• pp.35-40
• /
• 2004

In this study, we collected data used to formulate the relationship between quantitative metrological parameters in CRT display and the perceived focus quality. Human perception of the focusing quality was evaluated in terms of user feedback scores regarding the character legibility from four highly trained inspectors. Thirteen CRT monitors from five different manufacturers were compared relatively with respect to the norm monitor. The profile of electron beam such as spot size and the shape of distribution made by electron beam, contrast, convergence of RGB beams, and luminance characteristics were measured using a precision measurement system. Linear regression analysis and artificial neural network models were used to formulate the relationship between human perception and the quantitative measurements. The accuracy of the formulated linear regression model ($R^2$=0.515) was not satisfactory but the nonlinear neural network model ($R^2$=0.716) was fairly convincing and robust even the utilized data included subjective differences.

• Journal of the Optical Society of Korea
• /
• 제15권3호
• /
• pp.310-317
• /
• 2011

Perceptibility and acceptability are the most often used threshold units in the field of color science. The former refers to a just perceptible difference and the latter evokes a tolerable color difference. Such thresholds can be very significant to color quality control processes in the printing industry and should be defined in quality measure units. Optical density (OD) and color difference models are usually utilized as color quality measures and have been provided in a considerable number of commercial measuring devices such as spectrophotometers. However, their merits and traits are far less understood in the literature. The present study intends to evaluate performance of those color quality measures including the OD and widely known color difference models, e.g. ${\Delta}E{^*}_{ab}$, ${\Delta}E_{CMC(l:c)}$ and ${\Delta}E{^*}_{00}$. A set of psychophysical assessments were carried out in order to accumulate the perceptibility and acceptability thresholds data, and their central trend was compared with the color quality measure estimates.

• 대한인간공학회지
• /
• 제18권3호
• /
• pp.1-12
• /
• 1999

This study investigated human operator's perceptual and psychophysical responses to vibrotactile stimulation on various parts of the hand. Using a small vibrotactile display, the effects of three mechanical parameters consisting vibrotactile stimulations, i.e., vibration frequency, pulse-width modulation duty cycle, and number of contactors, on differential thresholds were examined at five different loci of the hand. It was observed that differential threshold varies with vibration frequency and number of active contactors. Differential sensitivity was the greatest at the vibration frequency of 120 Hz. The differential sensitivity was not found to be affected by loci on the hand. The area of stimulation on the hand was also found to be significant in that the sensitivity increased with the number of active contactors. It should be noted that the conclusions from this study generally correspond to those from the previous study on the absolute sensitivity. which means that tactile sensitivity to vibrotactile stimulations can be controlled with a systematic and consistent passion for emulating normal everyday contact on human hands in teleoperation and virtual reality applications.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.745-748
• /
• 2008

The theory of Bartleson and Breneman that the perceived image contrast changes with surround luminance (the lighter surround provides higher contrast) was tested an over bright condition($8500d/m^2$). Contrarily to the Bartleson and Breneman's results, we observed the fact that perceived constrast was decreased when surround huminance increased from dark to over bright through two sets of psychophysical experiments based upon both uniform gray patches and complex color images.

• 한국주거학회논문집
• /
• 제14권1호
• /
• pp.19-27
• /
• 2003

This study aims to survey the living spaces of the welfare facilities for the aged to get the objective relationships between the physical thermal environment and the users' subjective responses. The surveys were made twice in winter and once in summer during 2001 and 2002. An ambient temperature, relative humidity, air velocity, globe temperature were measured as physical elements of thermal environment and the ASHRAE Psychophysical Voting Scale were used as an evaluation index for subjective responses. As the results, the aged respond thermally comfortable, in spite of the differences among important factors such as thermal sensations, humidity sensations and air velocity sensations. Also the physical thermal environmental elements and the subjective responses indices exceed thermal comfort range calculated by PMV(Predicted Mean Vote) and PPD(Predicted Percentage Dissatisfied). It shows that the insulation of walls of the facilities is not enough for heating and cooling seasons, and the indoor environmental control is necessary.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1992년도 춘계공동학술대회 발표논문 및 초록집; 울산대학교, 울산; 01월 02일 May 1992
• /
• pp.573-580
• /
• 1992

인공건물의 평면특성에 대한 시각을 통한 인지를 청각으로 대체했을 경우의 인지능력을 측정하였다. 정상적으로 시각(visual)을 이용하겠으나, 시각 장애자의 경우는 청각(auditory) 또는 촉각(tactile) 또는 두가지 모두를 사용하게 된다. Psychophysical approach를 사용하여 모의평면에 대한 인지능력을 JND단위로 측정하였다. 청각적인 신호를 관찰자에게 제공하기 위해 전자장치(electronic ranging device)가 고안되었다. 이 장치는 목표물까지의 거리를 초음파의 이동시간으로 측정하여 음의세기(sound level)로 발생시켜 준다. 관찰자는 이 음의 세기를 듣고 거리를 추정하고 물표의 방향은 이 장비를 쥔 손의 방향, 즉, proprioceptive cue를 이용하게 된다. 세가지 task에 대한 실험은 평면의 slantness, 두 평면이 교차하는 모서리의 크기, 두 평면사이의 공간(aperture size)등에 대한 인지능력의 측정실험이다. 실험결과를 보면, 관찰자는 시각신호 대신에 청각신호를 사용할 수 있는 능력이 있는 것으로 나타났다. 세가지 task별 JND측정치는 slant angle 6도, 모서리의 concavity 10도, angular aperature size 3-5도로 나타났다. 이 결과는 정상인이 시각을 이용한 인지능력과 큰 차이가 없음을 보여주고 있다.

• 대한인간공학회지
• /
• 제14권1호
• /
• pp.1-7
• /
• 1995

In this paper, the effectiveness and accuracy of using the direct estimation method were investigated in determining a worker's lifting capacity or the maximum acceptable weight of lifting (MAWOL) of symmetrical fifting tasks in the workplace were investigated. Six lifting tasks involving two vertical fifting start-end points (0-80cm, 47-102cm) and three lifting frequencies (1, 2, and 4 lifts/minute) were studied. Ten young, male subjects performed the six lifting tasks to predict the MAWOL using the psychophysical method and the direct estimation method. The main results indicated that there were no significant differences between the MAWOLs determined by the two methods except for the lifting frequency of 4 lifts/minute. Analysis of variance was performed on the task rating data to check the consistency of the task rating across subjects, which revealed no significant difference.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2010년도 춘계학술대회 논문집
• /
• pp.1017-1025
• /
• 2010

The Purpose of this paper is to characteristics and analysis of ride comfort by using HRV. Although the riding comfort of trains has been managed by setting allowable accelerations of 3-axis motion in cabins, it is impossible for this approach to express the psychophysical relationship between various vibrational factors and riding comfort. in order to propose a function to evaluate the riding comfort of train on conventional railroad, an experiment was performed with the Korea Tilting Tran eXpress(TTX). As a result, by referring to some international standards on the method of evaluating ride comfort, a modified method was proposed to evaluate the lateral vibration in addition to the roll motion on carve transitions.

• The Journal of the Acoustical Society of Korea
• /
• 제15권3E호
• /
• pp.37-44
• /
• 1996

A new method for efficient modeling of the Head-Related Transfer Functions(HRTF's) without loss of any directional information is proposed. In this paper, the HRTF's were empirically measured in a real room and modeled as the ARMA models with common AR coefficients and different MA coefficients. To assess the validity of the proposed ARMA model, psychophysical tests show that the proposed ARMA model, in comparison with the conventional MA model, requires a small number of parameters to represent empirical HRTF's and improves the back-to-front confusions in sound-field localization. Thus, significant simplifications in the implementations of sound-field synthesis systems could be obtained by using the proposed ARMA model.