• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1391-1395
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• 2011

In this paper, would implement a transceiver for the visible light communication that based on wireless communication driving technology for LED illumination-based infrared ray communication, and measurement analyzed a design error rate of a transceiver variable rate has made about distance change -2.5m. The error rate measured a voltage variable along illuminate change between switchable circumstances, which has illuminated insight and outright. Each analyzed and measurement on the communication distance errors along the differences of disturbance light between night and days. The LED module has implemented for number of 6 through illumination dimming in case of different values. Also, implementation for the system module of a VLC transceiver based on the infrared sensors which used feedback outcome value has analyzed with error rate.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.967_968
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• 2009

For lighting application, high-power LED nowadays is driven at 350mA and a sensing resistor is used to provide feedback for LED-current regulation. This method adds an IR drop at the output branch, and limits power efficiency as LED current is large and keeps increasing. In this paper, a power efficient LED-current sensing circuit is proposed. The circuit does not use any sensing resistor but extracts LED-current information from the output capacitor of the driver. Controlling the brightness of LEDs requires a driver that provides a constant, regulated current. In one case, the converter may need to step down the input voltage, and, in another, it may need to boost up the output voltage. These situations often arise in applications with wide-ranging ""dirty"" input power sources, such as automotive systems. And, the driver topology must be able to generate a large enough output voltage to forward bias the LEDs. So, to provide this requirements, 13W prototype Buck-Boost Converter is used.

• Journal of Information Science Theory and Practice
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• v.1 no.3
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• pp.12-32
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• 2013

The paper introduces the research area of interactive information retrieval (IIR) from a historical point of view. Further, the focus here is on evaluation, because much research in IR deals with IR evaluation methodology due to the core research interest in IR performance, system interaction and satisfaction with retrieved information. In order to position IIR evaluation, the Cranfield model and the series of tests that led to the Cranfield model are outlined. Three iconic user-oriented studies and projects that all have contributed to how IIR is perceived and understood today are presented: The MEDLARS test, the Book House fiction retrieval system, and the OKAPI project. On this basis the call for alternative IIR evaluation approaches motivated by the three revolutions (the cognitive, the relevance, and the interactive revolutions) put forward by Robertson & Hancock-Beaulieu (1992) is presented. As a response to this call the 'IIR evaluation model' by Borlund (e.g., 2003a) is introduced. The objective of the IIR evaluation model is to facilitate IIR evaluation as close as possible to actual information searching and IR processes, though still in a relatively controlled evaluation environment, in which the test instrument of a simulated work task situation plays a central part.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.94-100
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• 2004

We have investigated the magnetic domain structure and the thermal stability of magnetotransport properties of IrMn biased spin-valves containing Co, CoFe and NiFe. The magnetic domain structures were imaged using a magneto-optical indicator film(MOIF) technique. To investigate the thermal stability, magnetoresistance(MR) was measured at annealing temperature(TANN) and room temperature($T_{RT}$) followed by the annealing. Domain imaging reveal that the increase of annealing temperature led to changes in the exchange coupling between the two ferromagnet(FM) layers through nonmagnetic layer rather than between FM and antiferromagnet. unlike the NiFe biased IrMn spin valve with large domains, MOIF pictures of Co and CoFe biased IrMn spin valve structures show the formation of many small microdomains. The magnetic structure, as revealed by the domain images, appeared unchanged while the MR dropped dramatically. From the combined giant magnetoresistance(GMR) and MOIF results, it was apparent that the decrease of MR ratio was not related to the spin valve magnetic structure up to about $350^{\circ}C$($T_{RT}$ ).

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.85-91
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• 2024

With the current surge in leisure sports activities involving firearms and the costly shooting practices in the military, there's a growing interest in using virtual reality as a cost-effective alternative. This study proposes a system that addresses the drawbacks of existing shooting practice setups, such as dim spaces and high installation costs, by making it feasible on large display screens. The system integrates IR receivers and guns for practice, ensuring usability and efficiency through an application. Additionally, an accuracy adjustment feature enhances precise coordination recognition. As a result, this cyber light gun system offers an affordable solution for outdoor training.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1513-1518
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• 2012

This paper is implemented media transmission system of VLC transmitter and receiver module using LED of White lighting that is based on PC module and to transmission technology for performance analysis. To realize LED visible light communication receiver is used 1~12 LED light-emitting device and transmitter is used a variable sensor. Developed initial distance of the tranceiver is more than 0~1m for LED VLC and the overall system transmission speed is achieved on variable having Visible light media transmission system. Composition to PC module with LED module and infrared sensor for performance analysis, predict and analyze the communication distance, check about the possibility of application methods. Measure each performance when the lens wearing and not wearing in order to increase the overall efficiency of the LED module, can know that increase efficiency of approximately 20%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.234-238
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• 2014

Multichip packaging was achieved the best solution to significantly reduce thermal resistance at the same time, to increase luminance intensity in LEDs packaging application. For the packaging, thermal spreading resistance is an important parameter to get influence the total thermal performance of LEDs. In this study, silicon-based multichip light emitting diodes (LEDs) packaged module has been examined for thermal characteristics in several parameters. Compared to the general conventional single LED packaged chip module, multichip LED packaged module has many advantages of low cost, low density, small size, and low thermal resistance. This analyzed module is comprised of multichip LED array, which consists of 32 LED packaged chips with supplement power of 0.2 W at every single chip. To realize the extent of thermal distribution, the computer-aided design model of 6.4 W Si-based multichip LED module was designed and was performed by the simulation basis of actual fabrication flow. The impact of thermal distribution is analyzed in alternative ways both optimizing numbers of fins and the thickness of that heatsink. In addition, a thermal resistance model was designed and derived from analytical theory. The optimum simulation results satisfies the expectations of the design goal and the measurement of IR camera results. tart after striking space key 2 times.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.47-56
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• 2010

For a human being's smooth activity, the clean air and comfortable lighting environment are needed. The suitable lighting environment is obtained generally by making it available for being formed the bright situation easy for seeing object and the visually comfortable atmosphere. In this way, even the lighting environment was changed along with economic development. Even a light source was diversified. Thus, several kinds of new light sources such as LED, OLED, PLS, and CNT came to appear. Halogen lamp, which has low efficiency due to high color rendering among lamps of being used now, is being much used yet. However, owing to radiation of UV and IR, there are many limitations to the subject in general exhibition lighting, museum, and art museum. Accordingly, a research was performed on filter that is blocked UV and IR at the same time, by using halogen lamp that is excellent in color rendering and in life.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.106-111
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• 2020

In this paper, we propose the non-contact gesture recognition system and algorithm using proximity-based sensors. The system uses four IR receiving photodiode embedded on a single chip and an IR LED for small area. The goal of this paper is to use the proposed algorithm to solve the problem associated with bringing the four IR receivers close to each other and to implement a gesture sensor capable of recognizing eight directional gestures from a distance of 10cm and above. The proposed system was implemented on a FPGA board using Verilog HDL with Android host board. As a result of the implementation, a 2-D swipe gesture of fingers and palms of 3cm and 15cm width was recognized, and a recognition rate of more than 97% was achieved under various conditions. The proposed system is a low-power and non-contact HMI system that recognizes a simple but accurate motion. It can be used as an auxiliary interface to use simple functions such as calls, music, and games for portable devices using batteries.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.1007-1010
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• 2011

$Ir(dpq/dpqx)_2$(przl-R) complexes were prepared and their electrochemical properties were investigated, where dpq, dpqx and przl-R represent 2,3-diphenylquinoline, 2,3-diphenylquinoxaline and N-phenyl-R-pyrazolonate derivatives, respectively. The iridium complexes containing dpq and dpqx as main ligands were reported to show red phosphorescence, and involvement of a pyrazolonate ancillary ligand in the iridium complexes led to high luminous efficiency for organic light-emitting diodes. In this study, we synthesized red phosphorescent iridium complexes containing a new pyrazolonate ancillary ligand and investigated the HOMOs, LUMOs and resulting electrochemical gaps of $Ir(dpq/dpqx)_2$(przl-R) by cyclic voltammetry. The emission wavelengths of the complexes at 600 - 640 nm were consistent with the gaps of 1.95 - 2.03 eV measured from reduction and oxidation potentials of the complexes.