• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.56-56
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• 2019

본 연구에서는 자생 상록 목본 3종의 실내도입을 위하여 몇 가지 광량조건에서의 식물생육 및 광화학 반응을 조사하였다. 식물재료는 황칠나무[Dendropanax trifidus (Thunb.) Makino ex H. Hara], 먼나무(Ilex rotunda Thunb.), 편백[Chamaecyparis obtusa (Siebold & Zucc.) Endl.]의 2년생 실생묘를 유리온실에 재배하면서 실험에 사용하였다. 실내에 조사되는 광환경을 측정하여 광량 10, 50, 100 및 200 PPFD(${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)를 처리구로 설정하였다. 실내환경은 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$) 및 습도($55{\pm}3%$)를 유지하였으며, 1회/3일 간격으로 관수하였다. 유리온실에서 동일기간 동안 재배중인 식물을 대조구로 사용하였으며, 실험은 8주간 수행되었다. 황칠나무와 먼나무는 200 PPFD의 높은 광량에서 초장, 줄기직경, 엽장, 엽수 등의 생육수치가 우수하였다. 반면 두 종 모두 10 PPFD 광량에서는 재배기간 중 잎이 말라가는 현상이 관찰되었으며 8주차에 모든 식물체가 고사하였다. 이는 10 PPFD 광량에서 재배된 황칠나무와 먼나무의 광화학반응에서도 Fv/Fm (-0.10, -0.08) 및 Fm/Fo (0.91, 0.93)가 낮은 수치로 조사된 반응과 일치하였다. 한편 편백나무는 모든 광량조건에서 대조구에 비해 초장 및 줄기직경 등의 생육이 우수하였으나, 10 PPFD의 낮은 광량에서는 Fv/Fm (0.16) 및 Fm/Fo (1.60)가 타 처리구에 비해 낮은 수치로 조사되었다.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.334-343
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• 2020

In this paper, a study of the design of a lighting optical system to form indirect light was conducted, to reduce the glare caused by the hot spot of the LED. In the case of using an LED for indoor lighting, glare is caused because of the high luminance and non-uniform luminance distribution. In particular, LED stands are located close to the user's eyes and are used for a long time, so research to reduce glare is essential. Therefore, in this paper an optical system structural study and the design of an LED stand for glare reduction were conducted. Afterward, the luminance analysis and comparison to an existing LED stand product confirmed that the reflective LED stand proposed in this paper had better performance in terms of glare.

• Korean Journal of Materials Research
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• v.34 no.8
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• pp.400-407
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• 2024

The reversible metal electrodeposition (RME) process is used to prepare electrochromic mirrors with reflective-transparent optical states, by depositing metal particles on transparent conductive substrates. These RME based devices can be used in smart windows to regulate indoor temperatures and light levels, serving dual purposes as lighting elements. Commercialization efforts are focused on achieving large-scale production, long-term durability, and a memory effect that maintains coloration without applied voltage. Enhancing durability has received particular attention, leading to the development of electrochromic mirrors that employ gel electrolytes, which are expected to reduce electrolyte leakage and improve mechanical stability compared to traditional liquid electrolyte devices. The gel electrolytes offer the additional advantage of various colors, by controlling the metal particle size and enabling smoother, denser formations. In this study, we investigated improving the durability of RME devices by adding polyvinyl butyral (PVB) to the liquid electrolyte and optimizing the concentration of PVB. Incorporating 10 % PVB resulted in excellent interfacial properties and superior electrochromic stability, with 92.6 % retention after 1,000 cycles.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.3
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• pp.30-39
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• 2012

In this paper, a safe driving assistance system is proposed by detecting the status of driver's doze based on face and eye detection. By the level of the fatigue, safe driving system alarms or set the seatbelt on vibration. To reduce the effect of backward light and too strong solar light which cause a decrease of face and eye detection rate and false fatigue detection, post processing techniques like image equalization are used. Haar transform and PCA are used for face detection. By using the statistic of the face and eye structural ratio of normal Koreans, we can reduce the eye candidate area in the face, which results in reduction of the computational load. We also propose a new eye status detection algorithm based on Hough transform and eye width-height ratio, which are used to detect eye's blinking status which decides doze level by measuring the blinking period. The system alarms and operates seatbelt on vibration through controller area network(CAN) when the driver's doze level is detected. In this paper, four algorithms are implemented and proposed algorithm is made based on the probability model and we achieves 84.88% of correct detection rate through indoor and in-car environment experiments. And also we achieves 69.81% of detection rate which is better result than that of other algorithms using IR camera.

• 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 IKEEE
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• v.13 no.4
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• pp.116-124
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• 2009

Recently the CPU performance of modem chipsets or multimedia processors of mobile phone is as high as notebook PC. That is why mobile phone has been emerged as a leading ICON on the convergence of consumer electronics. The various applications of mobile phone such as DMB, digital camera, video telephony and internet full browsing are servicing to consumers. To meet all the demands the image quality has been increasingly important. Mobile phone is a portable device which is widely using in both the indoor and outside environments, so it is needed to be overcome to deteriorate image quality depending on environmental light source. Furthermore touch window is popular on the mobile display panel and it makes contrast loss because of low transmittance of ITO film. This paper presents the image enhancement algorithm to be embedded on image enhancement SoC. In contrast enhancement, we propose Clipped histogram stretching method to make it adaptive with the input images, while S-shape curve and gain/offset method for the static application And CIELCh color space is used to sunlight readability enhancement by controlling the lightness and chroma components which is depended on the sensing value of light sensor. Finally the performance of proposed algorithm is evaluated by using histogram, RGB pixel distribution, entropy and dynamic range of resultant images. We expect that the proposed algorithm is suitable for image enhancement of embedded SoC system which is applicable for the small-sized mobile display.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.624-629
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• 2018

The current study was conducted to develop a portable composite gas detector allowing the detection of both $CO_2$ and $CH_4$ gases by means of the Non Dispersive Infra-Red (NDIR) method. The gas detector is configured to radiate infrared waves using infrared lamps, where the wavelength of the infrared light is reduced due to absorption throughout the chamber, and this reduction (absorption) is detected by the absorption detector, before being converted and amplified to a 3.5V~6V electrical signal, providing as accurate a measurement as possible. The conventional singe sensor method measures the relative measurement by absorbing only specified wavelengths of infrared radiation, which in the case of gas detection leads to problems with accuracy due to the lack of a reference sensor when detecting light with a wavelength of only $4.26{\mu}m$. The dual sensor employed in this study provides a comparative measurement between the reference value derived from the wavelength of $3.91{\mu}m$, which is not influenced by other gas sources, and the measurement value derived from the wavelength of $4.26{\mu}m$, in order to reduce the errors and enhance the reliability, thereby allowing low power consumption for portable devices and multi-gas detection for both $CO_2$ and $CH_4$ gases. The portable composite gas detector developed herein provides a measurement rage of 0ppm~5,000ppm for $CO_2$ gas, and 0.5%vol for $CH_4$, which allows the determination of whether the $CO_2$ and $CH_4$ contents in indoor air are less than 1,000ppm or not. The current study established that the composite gas detector can be interlinked with firefighting appliances through portable devices or home automation, and is anticipated to be very effective in fire prevention.

• Journal of Preventive Medicine and Public Health
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• v.39 no.3
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• pp.221-228
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• 2006

Objectives: The purpose of this study was to shed further light on the effect of modifiable health behavior risk factors on dependence in activities of daily living, defined in a multidimensional fashion. Methods: The study participants were 10,278 middle aged Americans in a longitudinal health study, the Health and Retirement Survey (HRS). A multi-stage probability sampling design incorporating the effect of population sizes (Metropolitan and non-metropolitan), ethnicity (the non- Hispanic White, the Hispanic, and the Black), and age (age 51-61) was utilized. Basic Activities of Daily Living (ADL) were measured using five activities necessary for survival (impairment in dressing, eating, bathing, sleeping, and moving across indoor spaces). Explanatory variables were four health behavior risk factors included smoking, exercise, Body Mass Index (BMI), and alcohol consumption. Results: Most participants at baseline were ADL independent (1992). 97.8% of participants were independent in all ADL's at baseline and 78.2% were married. Approximately 27.5% were current smokers at baseline, and the subjects reported moderate or heavy exercise were 74.8%. All demographic characteristics and behavioral risk factors were significantly associated with the ADL status at Wave 4 except alcohol consumption. Risk behaviors such as current smoking, sedentary life style and high BMI at Wave 1 were associated with ADL status deterioration; however, moderate alcohol consumption tended to be more related to better ADL status than abstaining at Wave 4. ADL status at Wave 1 was the strongest factor and the next was exercise and smoking affecting ADL status at Wave 4. People who were in ADL dependent at Wave 1 were 15.17 times more likely to be ADL dependent at Wave 4 than people who were in ADL independent at Wave 1. Concerning smoking cigarettes, people who kept only light exercise or sedentary life style at Wave 1 were 1.70 times more likely to be died at Wave 4 than the people who did not smoke at Wave 1. Conclusions: All demographics and health behaviors at wave 1 had consistently similar OR trends for ADL status to each other except alcohol consumption. Smoking and exercise in health behaviors, and age and gender in demographics at Wave 1 were significant factors associated with ADL group separation at Wave 4.

• KIEAE Journal
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• v.17 no.1
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• pp.63-68
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• 2017

Purpose: Various studies to solve the problem of increased energy consumption in the buildings are being carried out recently. Especially, the economic feasibility and insulation performance of the air-cap have been verified so that various studies regarding the reduction of building energy consumption have been carried out. However, previous studies regarding the air-cap were only carried out based on the verification of its insulation performance according to the size and attachment position of the air-cap. Therefore, the purpose of this study is to suggest a detachable air-cap module for improving the performance of the windows, evaluate the performance based on cooling, heating and light environments and verify its effectiveness through a real-scale testbed. Method: In this study, the energy saving performance in the circumstance where there is no attachment of an air-cap (Case 1), the circumstance where there is the attachment of air-cap on the glass surface of window (Case 2) and the circumstance where there is the attachment of an air-cap on the window frame (Case 3) were compared in order to verify the performance of the detachable air-cap module (Case 4), and the electricity consumption of cooling, heating and lighting equipment to maintain the appropriate indoor temperature and Illuminance for each case was calculated and utilized as indicators for the performance evaluation. Result: The result of this study is as follows. 1) In this study, the detachable air-cap module which was easily detachable through the principle of the magnet was suggested. 2) When Case 4 is applied, the electricity consumption of cooling and heating equipment can be reduced by 27.5%, 13.2% and 3.4% in comparison with Case 1, Case 2 and Case 3 respectively. 3) When the air-cap is applied to the window, the lighting energy consumption increases by 4 % in comparison to the non application of the air-cap, and this factor or aspect should be considered when applying the air-cap. 4) According to the performance evaluation result in consideration of cooling, heating and light environments, Case 4 demonstrates an energy saving ratio of 22.6%, 10.6% and 2.7% in comparison to Case 1, Case 2 and Case 3 respectively, indicating that it is effective for improving the performance of windows.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.128-134
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• 2014

Recently, design and construction of street tunnels tend to focus on cost reduction and preservation of nature. Accordingly, research is actively being carried out to quickly detect fires when they occur in tunnels, which have partially closed structures. Among such research, fire detection methods using optical fiber sensors have a wide bandwidth and fast transmission speed, while using light as a medium. Therefore, it does not receive electrical interference and there is almost no loss of information during transmission, while also having little noise as well. In relation to this, a fire monitoring system that can accurately detect the location of fires in real time using shape memory alloy and optical cables was developed in this study. In order to verify the developed method, light loss measurement test was conducted according to indoor temperature changes, while also conducting fire simulation tests by installing test beds in common underground zones with different external environments of temperature and distance. Upon carrying out experiments, the fire monitoring system developed in this study was found to be able to detect fires in long distance sections in real time.