• 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.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.325-331
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• 2016

In driving at evening or night, we are not able to recognize the speed bump and so stop suddenly. It could result in accidents. And also, we have a restriction of street light installation in farm road because it could be harmful to the crops and driver could not recognize the walking people. It needs to develop the speed bump with light and streetlight to be non harmful to the crops. So, we develop both the speed bump and streetlight with LED which could be non harmful to the crops and be increased recognition of walking people in farm road. For LED lighting power, we use the solar cells, and piezoelectric elements. It has automatic on/off according to power saving rates without illumination sensor. Minimization of circuit elements and design of minimum resisters and low power LED was used for power saving in assuring 3-days.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.30-35
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• 2001

This experiment was undertaken to investigate the effect of root zone temperature during the night on absorption of mineral nutrients, growth, and fruit yield of the truss-limited hydroponic tomatoes in winter. The root zone temperature was either controlled to 10, 15, 20, $25^{\circ}C$, or left uncontrolled at ambient temperatures. Temperature of the covered beds rose as root zone temperature was raised, but it in all treatments was less than 3$^{\circ}C$ higher than that in the control. Raising root zone temperature, except $25^{\circ}C$, showed positive effect on plant height, leaf length, stem diameter, and plant fresh and dry weight, but not on T/R ratio which was the greatest in the control. Root activity in all treatments except $25^{\circ}C$ increased as compared to the control. Mean fruit weight, fruit count per plant, and fruit yield were the greatest in 2$0^{\circ}C$ treatment. Root zone temperature did not significantly affect the contents of total nitrate and magnesium in leaves, stems and roots. Concentrations of phosphate and calcium increased in leaves and stems, but decreased in roots as root zone temperature increased. Overall, 2$0^{\circ}C$ treatment gave the greatest growth and energy efficiency.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.178-184
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• 2011

Compressed Air Energy Storage (CAES) is a combination of energy storage and generation by storing compressed air using off-peak power for generation at times of peak demand. In general, both charging and discharging of high-pressure vessel are unsteady processes, where the pressure is varying. These varying conditions result in low efficiencies of compression and expansion. In this paper, a new constant-pressure CAES system to overcome the current problem is proposed. An energy analysis of the system based on the concept of exergy was performed to evaluate the energy density and efficiency of the system in comparison with the conventional CAES system. The new constant-pressure CAES system combined with pumped hydro storage requires the smaller cavern with only half of the storage volume for variable-pressure CAES and has a higher efficiency of system.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.723-730
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• 2023

Due to the recent development of battery technology, various types of means of transportation such as electric kickboards, Segways, and electric bicycles have emerged, which can be defined as Personal Mobility. In this paper, as the incidence of safety accidents increases due to the increase in the number of users of Personal Mobility, safety helmet devices that strengthen safety capabilities and peripheral recognition functions were studied. In order for the helmet to send a safety signal, Arduino was used as a base to set the value of the sensor according to changes in distance and angle using the ultrasonic sensor to minimize errors and ensure smooth recognition. In addition, a gyro sensor was used to turn on the direction indicator according to each slope. Using a CDS sensor, the LED is designed to turn on when it goes below 150 lux at night. Finally, it is possible to check whether a helmet is worn within 5cm, and when driving at an average speed, the direction indicator light is turned on at 10 degrees, and the LED is turned on at less than 150 lux.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1379-1386
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• 2023

In this paper, research was conducted to prevent various safety accidents that may occur from infant carriages carrying children and to make the use of infant carriages easier. In order to prevent the baby car from running without protection, a brake function is installed on the baby car wheels using a pressure sensor and a servo motor. Then, a pressure sensor and LCD are used to determine whether the seat belt is fastened to prevent the child from falling out of the baby car. In addition, it was designed to use LCD and LED to turn on a warning light when the temperature and humidity exceed a certain level, so that infants can be in a comfortable environment when using the baby car.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.87-89
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• 2007

선행 연구개발한 집단감시 디지털 시스템(Group Digital Surveillance System for Fishery Safety and Security, GDSS- F2S)은 대단위 양식장에 침입하는 도적을 방어하기 위하여 레이더 추적정보와 적아식별 정보를 제공하는 시스템이다. 그러나 GDSS-F2S에서 제공하는 두 가지 정보만으로는 도적행위를 입증할 수 있는 법적 증거자료로 미흡하다. 본 논문에서는 이러한 문제점 해결방안의 하나로 CCD 카메라를 이용한 영상획득 장치를 개발하여 GDSS-F2S에 부가한 연구내용을 기술한다. 영상획득 장치 개발에 앞서, 실험지역의 지리적인 특성을 고려한 도적침입 예상경로 분석과 도적행위 시나리오를 기반으로 유효한 대응수단을 검토한 결과, 영상획득 장치가 유효한 대응수단임을 확인하였다. 영상획득 장치는 저가이변서 성능이 우수한 0.0001 룩스의 초저조도 CCD 카메라와 부가장치를 이용하여 개발하였다. 6개월 이상의 장기 현장실험을 통하여 본 연구에서 개발한 시스템을 평가한 결과, 주간은 물론 1 미터 앞도 식별할 수 없는 야간에도 차량의 행동과 번호판 및 사람의 행동과 인상착의 등의 영상정보를 확보할 수 있었다.

• Atmosphere
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• v.28 no.3
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• pp.317-324
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• 2018

In this study, we review the ground-based whole-sky camera (WSC), which is developed to continuously capture day and night cloud images using the illumination data from a precision Lightmeter with a high temporal resolution. The WSC is combined with a precision Lightmeter developed in IYA (International Year of Astronomy) for analysis of an artificial light pollution at night and a DSLR camera equipped with a fish-eye lens widely applied in observational astronomy. The WSC is designed to adjust the shutter speed and ISO of the equipped camera according to illumination data in order to stably capture cloud images. And Raspberry Pi is applied to control automatically the related process of taking cloud and sky images every minute under various conditions depending on illumination data from Lightmeter for 24 hours. In addition, it is utilized to post-process and store the cloud images and to upload the data to web page in real time. Finally, we check the technical possibility of the method to observe the cloud distribution (cover, type, height) quantitatively and objectively by the optical system, through analysis of the captured cloud images from the developed device.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.14-21
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• 2004

This automotive headlight control system is newly proposed that, under my slope degree of the driving mad(flat up-hill, and down-hill) at night driving, the reflecting mirror of the headlight can be automatically controlled for safe driving. At first whether or not any vehicle is driven near is checked by photo sensor. Secondly, using the slope degree of the automotive feedbacked from the tilt sensor, the servo motor with the headlight is controlled to be turned right or down to the suitable angle. The servo motor is appropriately controlled according to road conditions. The proposed headlight control system is designed on the basis of the tested illumination intensity obtained according to any slope degree of roads. Finally, it is confirmed that the test model works very well in the given road conditions and environments.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.400-403
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• 2010

도로상의 안개로 인한 시정감소는 교통사고를 유발하는 주된 원인이므로 전방의 운전자에게 도로의 시정거리를 미리 알려주어 안전운행을 유도하기 위한 안개경고시스템은 도로의 안전관리를 위해 매우 중요한 요소이다. 우리는 CCTV 카메라 영상에서 도로상에 통행중인 차량의 이동영역이 시정에 따라 달라진다는 점에 착안하여 이동영역을 추출하고 이를 이용하여 가시거리를 계산하는 시정 측정 장치를 개발하고 있으며, 주간, 야간 등 날씨의 변화에 덜 민감하면서도 효과적이고 정확한 이동영역의 추출은 시정측정을 위해 매우 중요하다. 본 논문에서는 이동영역의 추출을 위해 영상대비를 이용하여 자동으로 임계치를 결정하는 방법을 제안하며, 결정된 임계치를 적용시킴으로써 프레임간의 차영상으로 부터 잡음이 효과적으로 제거될 수 있음을 보인다. 또한, 차영상을 일정시간 누적시키는 방법을 통해 효과적으로 차량의 이동영역이 추출 되는 것을 보이기 위해 실제 고속도로에서 촬영된 CCTV 영상을 이용하여 실험한 결과를 제시한다.