• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1392-1399
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• 2016

Blackout effect occurs when a driver misadapts to the changed lighting conditions upon entering a tunnel. This could lead to a decrease in visibility especially in the daylight, depending on the difference in the degree of brightness between inside and outside the tunnel. To alleviate such a problem, we decrease windshield transparency before the driver arrives at the tunnel entrance. Controlled amount of light inside the car can allow the drivers to adjust to the dark prior to entering. The windshield transparency coefficient is to be determined by the arrival time at the tunnel and difference in the level of brightness between inside and outside the tunnel. Navigation, road sign detection, and tunnel entrance detection provide the arrival time. We also designed an opto-electronic conversion function to estimate the level of brightness. The black-hole phenomenon alleviation method is verified by field experiments using an automobile camera and a navigation. The result shows that the adjusted windshield transparency is able to provide an environment with a comfortable level of brightness with which the drivers can enter tunnels without the visibility problem.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.976-979
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• 2005

This paper is about the development of automatic FPC(flexible printed circuit) punching instrument for the improvement of working condition and cost saving. FPC is used to detect the contact position of keyboard and button like a cellular phone. Depending on the quality of the printed ink and position of reference punching point to the FPC, the resistance and current are varied to the malfunctioning values. The size of reference punching point is 2mm and the above. Because the punching operation Is done manually, the accuracy of the punching degree is varied with operator's condition. To improve this manual punch ing operation to the FPC, automatic FPC punching system is introduced. Test algorithms and programs showed good results to the designed automatic punching system and led to the increasement of productivity and huge cost down to law material like FPC by avoiding bad quality.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2001.11a
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• pp.118-125
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• 2001

Most of the laws and standards relevant to technology in Korea bear a resemblance to those in Japan. Electricity was not introduced to Korea until Lighting ceremony in Kyong-Bok palace observed in 1887. Since Korea was annexed to Japan in 1910 and our public works were under Japan control we have applied Japanese laws and regulations made by Chosun government-general. Independently from Japan the power electricity accepted power plants of USA, codes of NESC, ASME / ANSI, NEMA. Our generation and distribution system takes American style while our consumer side takes Japanese style. As global trade system was transferred GATT into WTO, the harmonization of technological standards, certification construction testing in the trend of world. This paper is based on WTO / TBT agreement coming in effect after 12th, April, 1979. For Korea the distribution system has a strong resemblance to American system so that unconvertible because IEC 60364 originated from Europe while NEC originated from USA. This papers deals with the fundamental elements of electrical safety system with comparing IEC 60364 with NEC. This paper considers how engineers should apply NFPA 70(NEC) and IEC based on the comparison of NEC to IEC in relation to electrical installations.

• Journal of IKEEE
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• v.23 no.3
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• pp.826-831
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• 2019

The stand-alone photovoltaic power systems are widely used for lighting equipment and CCTV. In order for these devices to be competitive, the life of power storage devices such as batteries is very important. The characteristic Hybrid supercapacitor is the high power density and long life. We have proposed a stand-alone photovoltaic power system that uses hybrid supercapacitor. The charge and discharge characteristics and the internal resistance of the hybrid capacitor were measured to configure the power converter. A stable maximum output point tracking control algorithm is proposed even with the change in solar radiation. In order to verify the validity of the proposed system, a prototype was fabricated and tested using a 18W hybrid capacitor and a 10W solar cell.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.2
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• pp.55-60
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• 2022

A PSU (passenger service unit) is mounted on passenger seats in a cabin on an aircraft and consists of a crew call lamp, a reading lights, an information display lamp, an emergency oxygen generator, and an emergency oxygen mask. It is a safety device for providing convenience to passengers and providing oxygen to passengers in an emergency. This paper is a study on emergency oxygen supply systems and light systems of aircraft PSUs and a control device was developed to operate the system by analyzing the B767-300 aircraft's PSU circuit diagram. And the temperature generated by the B777-200ER aircraft's emergency oxygen generator was also measured by operating it directly. Through this, precautions for explaining the operation of an oxygen mask in an emergency were described and improvements were presented. Data acquired in these research processes can be used in the future to develop aircraft PSU (passenger service unit) and emergency oxygen generators.

• Journal of Environmental Science International
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• v.30 no.11
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• pp.907-914
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• 2021

In this study, strawberry cultivation environment in a greenhouse located in Jeonju was monitored and internal environmental parameters were analyzed. Temperature, humidity, RAD, and PPF sensors were installed to monitor environmental conditions in the test greenhouse. Data were collected every 10 minutes during four winter months from sensors placed across the greenhouse to assess its permeability and environmental uniformity. Temperature and humidity inside the greenhouse were relatively uniform with negligible deviations among the center, south, and north; however, it was judged that further analysis of gradients of these parameters from the east to the west of the greenhouse would be needed. Both RAD (Total solar radiation) and PPF (Photosynthetic photon flux) had high values on the south and were low on the north and the reduction rate of these parameters was 54% and 61%, respectively, indicating that a significant amount of light could not be transmitted. This implied a significant decrease in the amount of light entering the greenhouse during winter. Therefore, it is concluded that environmental control devices and auxiliary lighting are needed to achieve uniform greenhouse environment for efficient strawberry cultivation.

• Annual Conference of KIPS
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• 2009.11a
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• pp.559-560
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• 2009

네트워크를 이용한 LED 조명의 제어는 최근 IP(Internet Protocol)을 이용한 조명 제어와 융합되어 단순한 디밍(Dimming)제어 뿐만 아니라, 미디어 파사드(Media facade), 카이네틱 아트(Kinetic Art)등의 새로운 조명 분야로 범위가 확대 되고 있다. 본 논문에서는 다양화 되는 네트워크 기반의 제어 방식 중 DMX over IP 에 대하여 멀티케스트-다중화 방식(Multicast & Multiplexing)으로 분석 및 시뮬레이션 하였다. 그 결과 1 만개 이상의 채널 수를 가지는 규모가 큰(large volume) 조명 네트워크 시스템의 경우 채널의 개수 증가가 delay-throughput 에 영향이 적음을 알 수 있다.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.1-9
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• 2016

Plant growth and development strongly influenced by light quantity and its spectral composition. Young tomato plants were cultivated in growth cabinets under artificial light provided by red and blue light emitting diodes(LEDs) during 12 hours, then plants were exposed to monochromatic ultraviolet, blue, green and red lights as an end-of-day(EOD) treatment during 4 hours to study their effect on plant growth parameters. EOD lighting from various LEDs increased total fresh and dry weights as well as assimilation area compared to those in control. Blue light increased stem height, internode length and stem diameter. Monochromatic UV-A light reduced stem elongation, highly increased stomatal conductance. Compactness and health index of young tomato plants were increased in UV-A and red light treatments.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.40-44
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• 2002

A prototype of closed-type transplant production system(CTTPS) with fully environmental control was developed to produce massively quality transplants. Four photosynthetic photon flux(PPF) levels of 200,300,400 and 500$\mu$mol . m$^{-2}$ .s$^{-1}$ , four photoperiod levels of 1816 h,12/12h, 9/15 h and 6/18 h were provided to analyze the growth and development of cucumber plug seedlings(Cucumis sativus L., cv. Kyuewosalichungiang) as affected by PPF and photoperiod in a CTTPS. Effect of photoperiod on the growth and development of cucumber plug seedlings produced in a CTTPS was higher than PPF, Stem diameters dry weight of shoot and roots number of leaves, leaf with and length, and SPAD value of cucumber plug seedlings produced in a CTTPS were significantly high as compared to the control. But stem length of plug seedlings produced in a CTTPS was shorter than those of the control. Growth characteristics of cucumber plug seedlings raised at photoperiod of 6/18 h and PPF of 200$\mu$mol . m$^{-2}$ .s$^{-1}$ were similar to the those of the control. These results suggest that cucumber quality transplant can be produced at relatively short photoperiod and low PPF, It means that the electric energy consumed for the production of cucumber plug seedlings in a CTTPS can be saved.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.282-289
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• 2019

Reflective and solar LED road studs are being used as a way of securing visibility for road environments. Road markers have various advantages and disadvantages in terms of versatility, efficiency, simplicity and visibility as individual products of reflective type and solar LED. However, in addition to the above, it is possible to prevent secondary accident after accident, It has a common drawback that it is difficult to have. In this paper, we propose a road stud system incorporating a wireless control function using RF - based communication with existing solar LED road studs and a system for controlling them. The proposed system is called the smart road stud system and it can control the equipment through the central control unit and the relay unit connected to the central control room by incorporating the RF communication function in the existing solar LED road stud. In addition, since it is possible to control the lighting method, color, etc. according to the road condition, it is possible to provide the driver with the state of the road to perform the function for preventing the second accident after the accident. It also adds features that minimize the ongoing power consumption of LED and RF communications. In order to verify the validity of the proposed system, prototypes were produced and it was confirmed that it is possible to act as a university for prevention of accident after accident by linking with other traffic system besides accident prevention function by securing existing visibility.