• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.5
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• pp.19-25
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• 2015

The management of energy resources for efficient utilization of the energy resources while reducing the system costs is a critical technical issue. Among many kinds of the energy resource management, the energy reduction for indoor lighting systems is getting much concern as a large portion of energy consumption has been made for indoor lightings. In this paper, an energy-efficient lighting control scheme for indoor lighting systems in order to reduce the energy consumption by controlling the luminous flux and the lighting direction under the illuminance constraints is proposed. With the use of the user location information for the luminaire which is closely located to the user, the proposed scheme firstly sets the light direction of the luminaire to be aligned to the user location. Then, an optimization problem to find the luminous flux of each luminaire is formulated in order to minimize the luminous flux sum of the luminaires with the constraints for the dynamic ragne of the luminous flux, and the light flux for each luminaire is determined by the solution of the problem. Simulation results show that the proposed scheme outperforms the luminaire control scheme with only the luminous flux control in the evaluation of satisfaction of the required illuminance level.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.436-442
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• 2015

In this paper, we develop an indoor localization device which embeds localization information into indoor light-emitting-diodes (LED) lighting systems. The key idea of our device is the use of the newly proposed "bit stuffing method". Through the use of stuff bits, our device is able to measure signal strengths even in transient states, which prohibits interference between lighting signals. The stuff bits also scatter the parts of the signal where the LED is turned on, thus provides quality indoor lighting. Additionally, for the indoor localization system based on RSSI and TDM to be practical, we propose methods for the control of LED lamps and compensation of received signals. The effectiveness of the proposed scheme is validated through experiments with a low-cost implementation including an indoor navigation task.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.97-100
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• 2007

Recently, since adjustment systems of various CCT(Correlated Color Temperature) are much developed, lighting environment of indoor has created by such various CCT lighting systems. If an indoor image of fixed CCT will quickly correct images of various CCT, lighting or interior designers can utilize it to persuade his or her clients in the indoor lighting planning process. Therefore, this paper presents fundamental data which are RGB data of seven color images for the correction of image by three different CCT.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.285-291
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• 2010

In this paper, we demonstrate that indoor wireless optical communication is possible with an LED and a solar cell. A lighting LED is used for lighting and signal transmission. A solar cell is used for collecting light energy and signal detection. This scheme is very useful because transmission is possible without any additional communication systems. In experiments, wireless optical communication was carried out at a data rate of 9.6 kbps using a lighting LED and a solar cell.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.32-40
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• 2023

Recently, there are some outdoor floor advertising lighting devices as one of the active marketing methods. However, for outdoor use, there are many restrictions due to the Outdoor Advertisement Act, according to requiring high-output heat generation, waterproofing, and AC power, etc. The purpose of this study is to develop a Duo Light product optimized for indoor use through publicity and information guidance in normal times and automatic evacuation route guidance display in case of disaster, in conjunction with disaster safety. To that end, patent search and patent association analyses were conducted, and a comparative analysis with commercial products was conducted as a case study. In addition, prototypes were designed and produced through the review of operation principles, where field environment surveys and self-tests were conducted. Also, technology roadmaps were presented by preparing plans for expandability and advancement of products. For the analysis of technology commercialization, the feasibility of technology commercialization was examined through the analysis of Jolly's Model and Lean Canvas Model. The results of this study will be able to contribute to minimize human damage through the effective response to disasters, which can increase the effect of indoor advertising by using the proposed indoor floor advertising lighting device in advertising and disaster situations.

• KIEAE Journal
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• v.8 no.1
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• pp.45-52
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• 2008

Daylighting systems can improve the luminous quality of indoor environment and reduce the building's electric lighting energy consumption. For designing good daylighting, place the light where it is desired and avoid excessive contrasts, glare and high light levels. Sun scoop, light scoop and sun catcher systems have been used for alternative systems compared to other natural lighting systems. This study aims to evaluate daylighting performance of sun scoop, light scoop and sun catcher systems using scale model experiments. For the purpose, the 1/10 scale models of the systems were made as the same areas of glazing(10 percent of floor area) on the top of the center roof. Totally 15 measuring points of illuminance on the horizontal work plane were monitored from 09:30 to 12:30 on October 29, 2007. Agilent data logger and photometric sensors Li-cor were used. As the results, the topside lighting systems can improve the illumination uniformity than side lighting and top lighting. However, the appropriated shading system should be integrated to prevent the direct sunlight.

• Journal of the Optical Society of Korea
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• v.20 no.4
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• pp.488-499
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• 2016

We present a design and optical simulation of a cost-effective hybrid daylighting/LED system composed of mixing sunlight and light-emitting diode (LED) illumination powered by renewable solar energy for indoor lighting. In this approach, the sunlight collected by the concentrator is split into visible and non-visible rays by a beam splitter. The proposed sunlight collector consists of a Fresnel lens array. The non-visible rays are absorbed by the solar photovoltaic devices to provide electrical power for the LEDs. The visible rays passing through the beam splitters are coupled to a stepped thickness waveguide (STW) by tilted mirrors and confined by total internal reflection (TIR). LEDs are integrated at the end of the STW to improve the lighting quality. LEDs’ light and sunlight are mixed in the waveguide and they are coupled into an optical fiber bundle for indoor illumination. An optical sensor and lighting control system are used to control the LED light flow to ensure that the total output flux for indoor lighting is a fixed value when the sunlight is inadequate. The daylighting capacity was modeled and simulated with a commercial ray tracing software (Lighttools^TM). Results show that the system can achieve 63.8% optical efficiency at geometrical concentration ratio of 630. A required accuracy of sun tracking system achieved more than ±0.5^o . Therefore, our results provide an important breakthrough for the commercialization of large scale optical fiber daylighting systems that are faced with challenges related to high costs.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.852-857
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• 2010

In this paper, we proposed and demonstrated an indoor visible-light communication system using an array of light-emitting diodes (LEDs). The main idea is based on that the LEDs can be used not only for lighting but also for free-space optical communications. Because LEDs offer advantageous properties such as high brightness, reliability, lower power consumption and long lifetime, the indoor visible-light communication systems are going to provide high quality of service by the high radiation power of the LED lighting. Prototype of simplex channel for audio and the full-duplex channel for text message were developed. Results indicates the viability of creating inexpensive free-space optical communication transceivers that might be embedded in commercial light products to supports indoor wireless networking.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.2
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• pp.103-111
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• 2012

This paper introduces a novel concept of 'A Green LED Sensitivity Lighting System' which can automatically estimate QoS(quality of service) and emotional requirements of user using smart phone. And it can intelligently control ambient illumination lamp to conserve electric energy and to satisfy human sensitivity. The proposed system has 4 control modes; emotional lighting, smart lighting, green lighting and realistic lighting modes in order to comfort man's emotion, to maximize work efficiency, to save energy consumption and to make the entertainment more fun, respectively. When we choose green lighting mode for indoor office situations, an elaborate simulation shows that the proposed system with home network can reduce the energy by 50% compared to conventional light control system with a fixed time-based switching.

• Korean Institute of Interior Design Journal
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• v.18 no.4
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• pp.79-87
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• 2009

Residential Buildings should provide high-quality, comfortable environments to support the activities of their occupants. The indoor environment of residential buildings, which includes thermal, lighting, acoustic, and indoor air quality, has a significant impact on health and quality of life. The comfortable living environment in residential buildings result from appropriately combining these environmental quality factors, and the performance of building systems must be compatible with the activities of the occupants. The objective of this research is to investigate and analyze the relationship between physical environmental conditions and occupant responses for improving environmental quality (EQ) in apartment buildings with four different building orientations (i.e. E, W, S, N) in two different seasons (i.e. winter and summer). The occupant survey was conducted in actual apartment buildings. The Physical environmental conditions in apartment buildings differed substantially depending on space, outdoor weather conditions and building orientations. Each space within the same apartment building had different environmental conditions. Combinations of unbalanced physical environmental conditions in apartment building decrease occupants' satisfactions and their perceptions of overall residential quality. Occupants' satisfaction and their responses to physical characteristics of their residential environment is related to thermal, lighting, acoustic, and indoor air conditions in their buildings. The result from this research will help designers and researchers to identify problems and develop solutions for improving environmental quality from the occupants' point of view.