• International journal of advanced smart convergence
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• 제9권4호
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• pp.203-208
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• 2020

In this paper, we propose the design and implementation of a desktop LED stand and smart app that automatically adjusts color temperature and illuminance for optimal brightness and eye health by improving the structural problem of the LED stand. It is a tabletop LED stand that supports optimal brightness through color temperature control and heat transfer through infrared LED to relieve eye strain through blood circulation and muscle movement. The LED stand works with the smartphone to automatically adjust the optimal brightness and color temperature for the user's environment. In addition, the brightness of the infrared LED is adjusted to a living frequency of 4Hz to relax the eye muscles and reduce eye strain. This study implemented an effective measured data-based system of previous studies through the color temperature and illumination of LED lighting, and near-infrared rays, and presented meaningful results by conducting an experiment to prove the effect through subjects.

• 조명전기설비학회논문지
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• 제26권9호
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• pp.1-7
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• 2012

In this paper, we present a new lighting control method considering ambient light in addition to the required lighting illumination for efficient energy saving of a LED stand. We estimate accurate environmental illuminance using a cheap illuminance sensor by modeling measured- and actual-illuminance using quadratic polynomial approximation. The relation between PWM(Pulse Width Modulation) duty ratio and illuminance intensity is modeled by a linear model. Illumination of the LED stand is controlled by estimating the difference of required illumination and the estimated ambient illumination. The developed LED stand has reduced electric energy consumption compared with a conventional manually controlled LED stand with the same lighting source. In addition, human subject evaluation shows that the LED stand, which is applied the proposed method, is more satisfactory than conventional ones since the proposed automatic controlled illumination produce more accurately required lighting and it is convenient.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1299-1300
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• 2012

• 한국광학회지
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• 제31권6호
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• pp.334-343
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• 2020

본 논문에서는 LED의 hot spot으로 인해 발생하는 눈부심을 감소시키기 위하여 간접광을 형성하는 조명 광학계 설계에 관한 연구를 진행하였다. LED를 실내 조명의 광원으로 사용하는 경우, 높은 휘도와 hot spot으로 인한 불균일한 휘도 분포로 인해 사용자에게 눈부심을 발생시키는 문제점이 있다. 특히, LED 스탠드의 경우 사용자의 눈에 가깝게 위치되어 있으며, 장시간 사용되기 때문에 눈부심 감소를 위한 연구가 필수적이다. 따라서 본 논문에서는 눈부심을 감소시키기 위한 LED 스탠드 광학계 구조 연구 및 설계를 진행하였다. 이후, 기존 LED 스탠드 제품과의 휘도 비교 및 분석을 통해 본 논문에서 제안한 반사형 LED 스탠드가 눈부심 면에서 더 우수한 성능을 가지는 것을 확인하였다.

• 디지털산업정보학회논문지
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• 제17권1호
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• pp.1-6
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• 2021

In this paper, to expand the use of standalone street lights, an algorithm for controlling LED energy consumption was proposed. The proposed method uses an LED module of a standalone street light divided into n zones. This is a method of reducing total power consumption by preventing the increase in power consumption due to high heat generation by weakly operating the entire LED according to the illuminance. When the amount of sunlight decreases, the whole LED operates weakly and then brightens, and unlike streetlight that act as streetlight, a method of dividing LEDs by area and limiting the number of LEDs operating according to illumination intensity was proposed. This is a way to use a lot of time with limited battery capacity by reducing the generation of heat that consumes the most power in streetlight. It is also a method of continuously changing the initial usage area to improve the total usage time of the LED substrate. As a result of the experiment, it was found that the proposed method extends the service time because it generates less heat than the conventional stand-alone streetlight.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.206-209
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• 2003

This paper deals with stand-alone PV power generation system with charge and discharge controller for the LED road sign. Main power source of PV system are generally solar cell and battery. Therefore PV system can be classified into variable types in accordance with connection type between battery and solar sell. Mainly used on of them is direct connection type which has advantage such as simple structure and simple controller. To verify the proposed PV generation system for the LED road sign, the detail simulation and experiment results indicate that operating characteristics are verified by experiment with a laboratory prototype in this paper.

• 한국가구학회지
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• 제28권4호
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• pp.332-339
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• 2017

Today, our indoor space requires a user-centered considering design that satisfies even human sensitivity. The word 'sensitivity' is being frequently used in the design market recently and this means that consumers are becoming more sensitive. For this reason, the characteristics of Toyo Ito's architecture, which are innocent due to its natural structure and materials, are suggested as a sensitive lighting stand design which can relieve users' stress from daily life and bring a psychological stability. As such, sensitivity lighting can create a lighting environment that considers consumers in various spaces along with the development of new scientific technologies and develop in a new direction of aesthetical beauty and eco-friendly area. In this study, a natural and sensitive lighting stand is suggested where a variety of digital art techniques of LED are applied based on formative characteristics of relationship, one of Toyo Ito's architectural concept factors. Such sensitivity lighting designs can not only realize a type-free design but also suggest a creation of the atmosphere which is close to nature.

• 조명전기설비학회논문지
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• 제27권12호
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• pp.1-9
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• 2013

A standalone LED lighting system in using solar energy has been used usually less than 70W of lighting power because of a troublesome installation and maintenance. In this system, as more and more LED lighting power increases, the capacity of photovoltaic panel does proportionally, and to improve the charging efficiency of solar energy, MPPT(Maximum Power Point Tracking) techniques is used frequently, but the solar tracker is not. In this paper, a solar tracker which traces the light of the sun in varying hour to hour is studied to apply to the standalone LED lighting system. This solar tracker consists of twin axis for tracing the azimuth and altitude respectively, and it has a robust structure with safe mode to stand a strong wind. As a result of analysis, generating efficiency of the traced type has improved on the fixed one 28.84% on average.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.67-68
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• 2007

The introduction of high brightness LEDs with white light and monochromatic colors have led to a movement towards specialty and general illumination applications. Because drive circuit of illumination LED has an effect on efficiency and life, research about the drive circuit following LED characteristic is needed. This paper proposed a implementation of the stand-alone LED lighting system using battery from photovoltaic power generation.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.445-448
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• 2008

There are increased interests in using new regeneration energy due to the effect of the latest rising oil price. On this account, various practical applications using small stand-alone PV generation system are being made. In this paper, with intent to change mercury lamp using for existing garden lamp with high flux LED, we have considered load characteristic using high flux LED modules applied to PV system. It is simulated with PSIM and made experiment set with a 75[W] solar cell module, DC-DC converter, controller and battery.