• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.29-32
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• 1996

기존의 안과 진단 및 치료 기기의 안구 고정장치는 진단 및 치료에 있어서 피검사자와 검사자에 사이에 충분한 협조가 되지 않을 경우 진단의 비효율성과 치료의 안정성등의 문제가 발생하고있다. 따라서 이러한 문제를 보완하기 위하여 SLO의 전면 세극등을 소형의 반사경으로 대치하고 표시등을 후면의 먼거리에 수직으로 배열시켜서 피검사자에게 적당한 높이의 고정등을 선택하게하여 수직방향의 안구 위치를 고정시키고 SLO(Scanning Laser Ophthalmoscope)의 좌우 회전기능으로 표적의 수평방향을 근절시킨 후에 검사자의 조작으로 원격조정되는 서보장치를 이용하여 다시 반사경을 전방향으로 미세하게 회전되게하여 정확한 위치로 안구를 이동시키게 하는 원격조정 표적 추적장치를 개발하였다. 이에 따라 피검사자는 거울에 비친 먼거리의 허상을 보게 되어 세극등을 이용한 근접주사방식의 단점인 안구의 축동, 폭주등으로 인한 환자의 눈의 피로를 최소화하면서 피검사자의 안구를 검사자가 원하는 위치로 고정시킬 수 있게 함으로써 임상실험에서 안과 진단의 정확성과 관리도를 높이고 치료의 효율성과 안전성을 증가시킬 수 있는 원격조정 추적장치로써의 성능을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.298-301
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• 2014

최근까지의 교통사고 통계에 따르면 주간 보다는 야간에 더 많은 사고가 발생하며, 사고 원인 중 하나는 부적절한 조명 시설로 인한 시야 미확보, 눈의 피로감 증가가 중요한 요소이다. 본 논문에서는 스마트폰 기반으로 야간 도로 밝기 측정 어플리케이션을 구현하여 야간에 부적절한 조명 시설이 설치된 지점을 파악하기 위해서 위치 정보와 밝기 정보, 이동 방향 정보를 실시간으로 데이터베이스에 저장하여 모니터링해주는 시스템을 설계 및 구현하였다. 이를 위해, 안드로이드 NDK을 이용하여 Native 환경에서 차선 검출 및 RGB 색 공간의 값을 휘도 값으로 변환 알고리즘을 작성하였다. 또한 스마트폰의 카메라를 이용하여 실시간으로 도로 영상을 입력 받은 후 ROI 설정 하여 연산 속도를 향상시켰고, 차선 검출을 통해 차선 사이의 도로 밝기 정보를 획득하고 GPS 센서를 이용하여 이동 방향 정보와 위치 정보를 획득하여 데이터베이스에 저장하였다. 어플리케이션 사용자들의 주행 정보를 바탕으로 도로 밝기 값 데이터베이스를 활용하여 눈부심 및 조명관련 사고 위험 구간을 자동으로 알려주는 후속 연구를 진행할 수 있을 것으로 기대한다.

• Journal of Korea Multimedia Society
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• v.19 no.9
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• pp.1723-1737
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• 2016

When watching 3D contents, people often experience various visual discomforts like tiredness, dryness, headaches, and dizziness. Previous researches on visual discomfort analyzed and concluded vergence-accommodation conflict, viewing distance, and brightness changes to be the causes of visual discomfort. Yet it is necessary to systematically analyze the visual discomfort due to the changes in object, background brightness and viewing distance. In this paper, we produce four videos that have four different background brightness and two different viewing distances to solve analyze the visual discomfort from watching 3D contents. We measure and analyze eye-blink and saccadic movement, saccadic latency, Nearest Point of Convergence (NPC), and participant survey for amore accurate result compared to previous researches. Our results show that the eye-blink rate and saccadic latency increase when the background is bright and viewing distance is close while the saccadic movement decreases in the same environment. However, NPC only changes when the background brightness changes. We confirm that the bright background and near viewing distance create greater visual discomfort and decrease depth perception abilities.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.69-80
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• 1998

This research was designed to investigate how the exercise program affects paraplegic standing and walking employing functional electrical stimulation(FES). Emphasis was also given to fatigue of major lower extremity muscles induced by different types of electrical stimulation. We applied continuous and intermittent rectangular pulse trains to quadriceps of 10 normal subjects and 4 complete paraplegic patients. The frequencies were 20Hz and 80Hz, and the knee angle was fixed at 90$^{\circ}$and 150$^{\circ}$to investigate how muscle fatigue is related to muscle length. The knee extensor torque was measured and monitored. We have been training quadriceps and gastrocnemius of a male paraplegic patient by means of electrical stimulation for the past two year. FES standing was initiated when the knee extensors became strong enough to support the body weight, and then the patient started FES walking utilizing parallel bars and a walker. We used an 8-channel constant-voltage stimulator and surface electrodes. The experimental results indicated that paralyzed muscles fatigued rapidly around the optimal length contrary to normal muscles and confirmed that low frequency and intermittent stimulation delayed fatigue. Our exercise program increased muscle force by approximately 10 folds and decreased the fatigue index to half of the initial value. In addition, the exercise enabled the patient to voluntarily lift each leg up to 10cm, which was of great help to the swing phase of FES walking. Both muscle force and resistance to fatigue were significantly enhanced right after the exercise was applied every day instead of 6 days a week. Up to date, the patient can walk for more than two and half minutes at 10m/min while controlling the on/off time of the stimulator by pushing the toggle switch attached to the walker handle.

• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.325-340
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• 1998

A cross-sectional study was conducted to evaluate the relationship between sick building syndrome(SBS) and the environmental factors affecting SBS on 130 underground workers and 60 controls. The study consisted of 1) a review of environmental condition 2) measurement of temperature, $O_2$, $CO_2$, CO, and formaldehyde and 3) a questionnaire survey of symptom prevalence and perception of environmental conditions using indoor Air Quality questionnaire recommended by National Institute for Occupational Safety and Health. Bronchitis and dust allergy were more prevalent in underground workers significantly(p < 0.05). Among the 18 symptoms related to the indoor air pollution, the experience rate of dry, itching or irritated eyes, sore or dry throat, chest tightness, tired or strained eyes and dry or itchy skin symptom was significantly different between the underground workers and controls. The diagnostic criteria of SBS was defined as at least 1 symptom is experienced 1-3 times a week during the last 1 month among 18 indoor air pollution related symptoms which can be relieved by moving out of the underground. Applying the criteria, the mean symptom score was significant higher in underground workers than controls significantly (p < 0.05). These resalts indicated that underground workers are under inappropriate ergonomic and physical condition and inadequate ventilation. Their experience rate of symptoms related to indoor air pollution and prevalence of SBS was significantly higher than controls. To reduce the prevalence of SBS of underground workers, the surveillance system of indoor air quality, restriction of using fuel in underground and legislative regulations for the environment are needed to establish a better indoor air quality. Early detection, treatment and prevention of SBS through medical attention is also needed.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.473-479
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• 2013

Purpose: This article tried to find the changes of the eye and a correlation depending on watching a smartphone and taking in alcohol. Methods: This paper conducted the refraction inspection, the radius of corneal curvature, tonometry and the corneal thickness measurement and analysis for 31 persons (18 males and 13 females) who have healthy drinking habit, not having the medical history of taking medicine related with disorders of the eye, a mental disease, systemic disease and alcohol metabolism. Results: Of respirations depending on watching a smartphone, the alcohol concentration was significantly decreased in 15 minutes, 30 minutes, 45 minutes, 60 minutes and the convalescent stage. (p<0.01, p<0.001) As the result of comparing the refraction inspection after and before watching a smartphone when drinking alcohol, there was a significant difference in the cylindrical power and the axis. (p=0.005, p=0.001) The change of intraocular pressure depending on watching a smartphone after drinking alcohol was decreased significantly from 30 minutes (p<0.001), and watching a smartphone didn't have any significant effect on the corneal thickness depending on the elapsed time from when drinking alcohol. Conclusions: Watching a smartphone and taking in alcohol had a significant effect on the cylindrical power and the axis. Watching a smartphone and taking in alcohol which may cause the visual function-strain are the factors that need to consider before the refraction inspection.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.75-86
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• 1998

The purpose of this study is to evaluate the effects of continuing work on VDT(video display terminal), therefore this study examined visual fatigue, unaided visual acuity, refractive error, accommodation and horizontal phoria of 152 subjects who did two hour long VDT work. For the ocular symptoms, the greatest number was tired eyes accounting for 45.71%. In the visual symptoms, blurred vision was the hightest rate of 80.39% and in case of systemic symptoms shoulder pain was 33.33% marked top ranking. The average of near visual acuity decresed almost 10% from 0.47 to 0.42, but refractive error increased about 0.10D to the direction of myopic shift. The amplitude of accommodation decreased approximately 0.72D from 7.46D to 6.74D. Accommodation facility was delayed from 2.27 second to 2.50 second, the amplitude of positive relative accommodation was decreased from 4.76D to 4.16D and the amplitude of negative relative accommodation was decreased from 2.46D to 2.33D. The horizontal phoria shifted to the direction of esophoria from $1.82{\Delta}$ to $3.24{\Delta}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3416-3422
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• 2014

A shock absorber rod is located in the center of the absorber piston and is responsible for the reciprocating movement portion. If it has surface defects, the damping performance of product will be adversely affected. A rod surface has gloss by heat treatment. Therefore, it is difficult to find a defect, such as dust, imprints, and blowholes. Because a total inspection is achieved by visual inspection by workers, it causes eyestrain and the quality of the product is not constant. In this paper, a machine vision system was developed to find a defect using a line-scan camera. The machine can detect surface defects than 0.3mm. To minimize the occurrence probability of defects on the inspection process, the developed auto inspection system had an automatic feeding system and incorporated a protection system. Through the development of this system, which relies on the operator's visual inspection of the surface of the shock absorber, the Rod inspection system constructed quality inspection standards and standardized tests to ensure improved reliability.

• Korean journal of communication and information
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• v.31
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• pp.327-354
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• 2005

This study deals with current use of e-books through a survey of e-book audiences and a diagnosis of the development perspective of e-book audiences. In addition, we present some effective methods to promote e-books in the future. The study shows that e-book users have increased. However, e-books are not well-known to the audience. Mainly, audiences use free web sites; consequently, the use of e-books is not well-promoted. Whether people have used e-books is statistically significant in the pattern of their use and e-book audiences prospect that the future of e-books is brighter than paper books. However, people who have used e-books prospect the brighter future for e-books than people who have never used them. Therefore, we should reconsider the accessibility to e-books, promote publicity, research the reliability of the contents, reduce the price, develop various contents, change layout for better readability, and develop the screen for the less eye fatigue to promote e-books.

• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.76-81
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• 2004

From September 1, 2003 to November 30, 2004, 20 mineral water wells were selected for some area in east Europe and the study on their water quality was analized. It revealed that mineral water contained considerable quantity of magnesium ions which helps the smooth activities of vascular muscles, nervous systems and protects skins from allergic reactions. It also lowers cholesterol level and contains high concentration of calcium ions which is one of the vital components of teeth and bone like phosphorus. Thus it is concluded that it is not qualified as boiler feed water as it has overall high degree of hardness by the presence of four times content of $Mg^{2+}\;and\;Ca^{2+}$.