• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.19-25
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• 2013

Purpose: The degree of the pupil covered with tinted region of circle soft contact lens was determined according to the illuminant conditions in everyday life and the change of visual acuity by its covering was further investigated. Methods: The circle contact lens having the non-tinted area of 6.2 mm in the center of the lens was applied on 82 eyes in their 20s and their minimum separable visual acuity and minimum legible visual acuity were determined under the luminances of 50 and 370 lux. Results: The covering of pupil was not found when wearing circle contact lens under 370 lux, however, some pupil covering ranged from 0.40 to 1.70 mm was observed in all subjects under 50 lux. The minimum separable visual acuity and minimum legible visual acuity were significantly decreased by the wearing of circle contact lens under 50 lux and the correlation between the larger pupil size of subjects and more decrease of visual acuity was observed. Furthermore, the decrease of minimum separable visual acuity was larger than the case of minimum legible visual acuity indicating that minimum separable visual acuity was largely affected by the covering of pupil. Conclusions: The consideration is necessary for the lens wearers and the manufacturers since the wearing circle contact lens in low-light indoor or nighttime activities may affect directly visual acuity.

• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.43-54
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• 2018

The aim of this study is to determine the effect of motion sickness on pupil rhythm. Sixteen volunteers of both genders (8 male, 8 female, mean age $25.67{\pm}2.43$ years) experienced VR contents in both 2D and HMD versions for 15 minutes, and their pupillary rhythms were compared. The irregular pattern of the pupillary rhythms, as demonstrated by increasing mean pupil diameter (mPD) and standard deviation of the pupil diameter (sPD), revealed motion sickness after experiencing HMD condition. The pupillary response is strongly related to the cognitive load, and the motion sickness can be interpreted as a change in the cognitive load caused by the increasing volume of visual information that must be processed and the conflict or inconsistency between different sensory modalities. The method proposed in this study could be a non-contact measurement method for the monitoring of motion sickness using a web-camera rather than previous sensor-based methods.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.212-220
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• 2013

Recently, there has been tremendous increase in human-computer/machine interaction system, where the goal is to provide with an appropriate service to the user at the right time with minimal human inputs for human augmented cognition system. To develop an efficient human augmented cognition system based on human computer/machine interaction, it is important to interpret the user's implicit intention, which is vague, in addition to the explicit intention. According to cognitive visual-motor theory, human eye movements and pupillary responses are rich sources of information about human intention and behavior. In this paper, we propose a novel approach for the identification of human implicit visual search intention based on eye movement pattern and pupillary analysis such as pupil size, gradient of pupil size variation, fixation length/count for the area of interest. The proposed model identifies the human's implicit intention into three types such as navigational intent generation, informational intent generation, and informational intent disappearance. Navigational intent refers to the search to find something interesting in an input scene with no specific instructions, while informational intent refers to the search to find a particular target object at a specific location in the input scene. In the present study, based on the human eye movement pattern and pupillary analysis, we used a hierarchical support vector machine which can detect the transitions between the different implicit intents - navigational intent generation to informational intent generation and informational intent disappearance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.145-148
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• 2010

본 논문에서는 3차원 스테레오 영상에서의 시각적 피로도와 안구의 운동량과의 상관관계를 도출하고 시각적 피로도 측정 시스템을 제안한다. 제안한 측정 방법은 3차원 스테레오 영상 시청자의 피로도가 누적되었을 때, 안구의 단속성 운동(saccade)이 감소할 것이라는 가정에 기반을 둔다. 액티브 셔터글라스 방식의 3D 안경을 착용한 시청자의 동공을 검출하고 추적하기 위해 적외선 광원 및 적외선 카메라를 이용한다. 획득한 영상에 대해 이진 임계화를 적용하고 타원 피팅을 수행하여 동공의 위치를 검출한다. 피팅된 타원의 이심률과 크기 및 위치를 제한하여 검출 오류를 줄인다. 검출된 동공의 위치를 바탕으로 안구의 단속성 운동량을 측정한다. 실험에는 변이 정도가 크지 않아 편안하게 시청 가능한 스테레오 영상과 과도한 변이를 가져 시청하는데 불편한 영상이 분리되어 사용되었다. 이들 영상에 대해 각각 실험자의 단속성 운동량을 측정하였다. 실험 결과에서 안구의 단속성 운동량이 변이가 큰 영상에서 그렇지 않은 영상에 비해 감소하는 경향이 나타났다.

• Analytical Science and Technology
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• v.13 no.2
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• pp.131-135
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• 2000

We studied adsorption isotherm, surface properties and antibacterial activity of Cu treated activated carbon fiber (ACF). The BET surface area of Cu treated ACF are distributed to $688.2-887.8m^2/g$. The adsorption results show that BET surface areas move gradually to lower value with increasing treated Cu mole concentration. Using t-method, the specific micropore volumes and average pore size were obtained. From the SEM study, it is also observed that many of micropores in activated carbon fiber are blocked surface after the treatment. And we also observed that the activity of E. coli in kind of colon bacillus increases gradually to larger range with increasing Cu mole ratio. From these results, we suggest the antibacterial mechanism for metal treated ACF.

• Clean Technology
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• v.19 no.4
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• pp.476-480
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• 2013

The growth behavior of $CH_4$ and $SF_6$ mixture gas hydrate has been investigated by a combined approach of Raman spectroscopy and molecular modeling. Raman spectroscopy results presented that when $CH_4$ is used only, $CH_4$ guest molecule is inserted first into the large cavity of the host structure built by $H_2O$ molecules and then into the small cavity to stabilize the whole gas hydrate structure. In the other hand, when $SF_6$ is mixed together, $SF_6$ is favored over (or competing with) $CH_4$ in being inserted into the large cavity and the small cavity still prefers $CH_4$ insertion. The calculations of binding energies clearly supported this. While $SF_6$ has a binding energy of -26.9 kcal/mol a little lower than -24.2 kcal/mol of $CH_4$ in the large cavity, $SF_6$ and $CH_4$ has 1.2 kcal/mol and -22.0 kcal/mol, respectively, in the small cavity. It indicates that the sizable $SF_6$ is not preferred in the small cavity but has a relative energetic advantage over $CH_4$ in the large cavity.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.166-167
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• 2004

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1541_1542
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• 2009

본 논문에서는 바이오/환경센서 응용을 위해 실리콘 기판위에 나노 동공구조 백금 전극을 작동전극으로 갖는 소형화된 용존산소센서를 설계 및 제작하고 그 특성을 분석하였다. 제작된 용존산소 센서는 15 mm $\times$ 8 mm $\times$ 0.6 mm의 소형화된 크기를 가졌으며, -0.9 V의 인가전위 시에 각각 산소 포화 상태와 무산소 상태에서 2.14 mA와 0.8 mA의 환원전류 특성을 보였다. 또한, 다양한 산소 농도상태에서 각기 다른 전류응답 차이를 보였다. 이를 통해서 다양한 산소농도에 대한 센싱특성을 검증하였다. 한편, 제작된 용존산소 센서는 전극제작에 사용된 나노 동공구조 백금 전극의 높은 촉매 특성에 기인하여 90% 전류응답시간이 7초 이내로 기발표된 다른 연구들에 비해 현저히 향상된 응답특성을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1816-1818
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• 2015

기존 시선추적 시스템의 문제점은 눈을 깜박이는 동안 동공의 크기 및 위치가 변화하여 시스템이 사용자의 시선 방향을 정확히 예측 할 수 없는 문제가 존재한다. 본 연구에서는 이러한 문제점을 해결하기 위해 얼굴이 포함 된 영상에서 눈을 검출하고, 눈 영역의 3개의 특징 (밝기 평균, 분산, 이진화 후 흑화소 영역 비율)을 추출하였다. 추출된 특징을 기계학습방법의 한 종류인 SVM을 이용하여 눈의 개폐여부를 판단할 수 있는 방법을 제안하였고, 그 결과 정확도는 81.4%가 나왔다. 제안한 방법은 동공을 검출하기 전 눈의 개폐를 먼저 확인할 수 있기 때문에 시선추적 시스템에서 처리시간을 단축시키고, 눈 깜박임에 따른 오차를 줄일 수 있다.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.469-482
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• 2018

Purpose : We investigated the change of spherical and comma aberrations after wearing aspheric soft contact lens (ASCL) in young myopes. Methods : Fifty young myopes ($23.15{\pm}1.70years$, spherical equivalent: $-2.90{\pm}1.75D$) were recruited and refractive errors were corrected using ASCL (Biotrue, Bausch+Lomb, USA). High order aberrations were measured in the 4 mm pupil size using the wavefront analyze and pupil sizes were measured with a pupillometer at the modes of scotopic condition (light off) at 3.5 m in the 100 lx illuminance condition. Results : Spherical aberrations and coma aberration of the 20s myopes were $0.026{\pm}0.031{\mu}m$ and $0.078{\pm}0.039{\mu}m$ respectively, and $0.019{\pm}0.026{\mu}m$ and $0.082{\pm}0.038{\mu}m$ after ASCL wear that spherical aberration was decreased and coma aberration was increased. However, spherical aberration was decreased in the 68% of the subject have positive spherical aberration, and increased in the 11% of the subject have negative spherical aberration. Coma aberration was increased in the 53% of the subject, did not change in the 19% of the subjects, and decreased in the 28% of the subject. Spherical aberration was not different with the refractive errors in low and moderate myopies, however, coma aberrations was higher in the higher myopes. Conclusion : In a scotopic condition without accommodation stimuli, spherical aberration is decreased after wearing ASCL, however in the subject have negative spherical aberration spherical aberration could be increased, and which is thought to be the influence of contact lens design and pupil size.