• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.1
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• pp.14-19
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• 1982

A differential amplifier has been designed and fabricated using aluminum-gate PMOS technology, Only enhaneement-mode MOSFET's are used in the circuit and the dimensions of transistors have been determined using simulation program MSINC. The fabricated integrated circuit with +15V and -l5V power supplies shows an open-loop DC voltage gain of 42 dB, a common mode rejection ratio (CMRR) of 50 dB, and a Power consumption of 20mW.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.233-236
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• 2011

This paper proposes to use gesture recognition technology to develop 3D game for prevention of dementia. In the game, the user can choose camera mode or mouse mode to play game. In the game design, We focused on the characteristics of dementia, Developed four types of games, Including Memory training game, Math game, Logical training game and 3D visual sense training game. Each type of game is composed by a number of small games. Common feature of all the game is random, This ensures that when user play games, Basically the game will not have the same situation. For the older elderly, If can take 10 minutes a day to play the game and has always insisted on playing, For dementia preventive have a positive effect.

• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.377-381
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• 2014

Coupled guided modes, proposed in various modified hollow hexagonal cavities each attached internally to a hexagon, were demonstrated by investigating the laser oscillations in semiconductor cavities. The mode spacing between two adjacent lasing peaks decreased as the size of the internal hexagon increased, due to the increased round-trip length of the coupled guided modes. The linear dependency of the inverse mode spacing to the calculated round-trip length strongly confirmed the lasing of the coupled guided modes. The proposed modes in common-sized external cavities showed resonance structure that could be adjusted widely by controlling the size of the internal hexagon.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.41-46
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• 1987

A new control scheme is developed to achieve fast and accurate decoupled tracking for an n-Joint robotic manipulator In the Presence of disturbances and unknown Parameter variations. The control system is designed so that a new type of state trajectories called sliding mode may exist in a phase plane. In order to remove the reaching Phase and high frequency chattering phenomenon which ate the common shortcomings of variable structure control(VSC) scheme, this paper presents the new switching line which is composed of three segments and the continuous control law which is derived from the existence condition of a sliding mode. The Proposed methods in this Paper are applied to a 3-Joint robotic manipulator as a numerical example-The digital simulation results which are compared with those of typical VSC scheme show the validity of accurate tracking capability and robust Performance of the system.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.164-172
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• 2001

This paper describes common MPPT(Maximum Power Point Tracking) control algorithm; Constant Voltage Control, P&O(Perturbation and Observation), IncCond(Incremental Conductance), and investigated it\`s efficiency. Though simulation and efficiency evaluation, the steady/transient states characteristics and efficiency of control algorithms are analyzed respectively. Also, two-mode MPPT control to improve on the existing control algorithm. Moreover, is proposed for high efficiency this paper suggests a topology for MPPT measuring efficiency and a method of examination.

• Journal of Power System Engineering
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• v.11 no.4
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• pp.12-17
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• 2007

Recently, many small and medium size diesel vehicles have been equipped with turbocharger and EGR system to get high performance and reduce $NO_x$ emissions but its application to heavy-duty diesel engine is not common yet. In this work, the simulation model for EURO-3 engine was developed using WAVE and then its performance and emission level were verified by comparing with experimental results. The possibility of current EURO-3 engine equipped with LPL EGR system which would be satisfied the EURO-5 regulation are examined. ESC 13 mode was chosen as the primary engine test mode, and the injection timing and fuel quantity were changed to compensate the lost engine performance caused by EGR. The system developed in this study shows that the current EURO-3 engine could satisfy EURO-5 $NO_x$ regulation by applying LPL EGR.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1718-1720
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• 1997

This paper deals with n rise in electric potential of telecommunication line for electric power system by lightning surges. When $1.2/50{\mu}s$ and $8/20{\mu}s$ impulse voltage and current were applied on telecommunication cable, the voltage waveforms at the end terminal and equipment were measured. The telecommunication lines, which consist of 60 conductors and 3.5km in length, have some surge protectors such as preposition lightning arrester and TVSS. In each case, the rise in electric potential was measured for differential mode and common mode, respectively. Also, the rise in ground potential and the induced voltages were measured and analyzed. As a result, a significant rise in ground potential was observed for lightning surge. It can cause failure or malfunction of telecommunication systems.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.248-256
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• 2008

The study aims at verifying no generation of electrical power induced noise voltage on telecommunications lineside cable by analyzing the practical findings of noise voltage produced at the telecommunication lines in the vicinity of electrified high-speed railways like KTX, while proposing to make the current standard measurement circuit along with its measuring conditions revised in compliance with international ITU-T recommendations by identifiably finding out the present problems in balance level measuring instruments as well as their errors in the measurement method now applicable by local telecommunications companies and the Radio Research Laboratory.

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.4
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• pp.131-137
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• 2006

The absorber in which heat and mass transfer phenomena occur simultaneously is one of the most critical components in the absorption system. It has the most significant influence on the performance and the size of the absorption system. During the absorption process, heat and mass transfer resistances exist in both liquid and vapor regions, so that the heat transfer mode should be carefully selected to reduce them. The objective of this paper is to review the previous papers analysing mathematical models of simultaneous heat and mass transfer phenomena during the absorption process. The most conventional working fluids ($H_2O$LiBr and $NH_3/H_2O$) are considered and the most common absorption modes (falling film and bubble mode) are dealt with in this review.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.3
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• pp.117-124
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• 2018

Wearable devices have become widespread. Fitness band is one of common wearable devices, providing useful functions. It helps users to monitor and collect their status such as heart rate and travel distance. Wearable devices, including fitness bands, are designed in small size and it ends up having small battery capacity. In that regard, it is necessary to expand the lifetime of wearable devices. Conventional power management scheme of wearable devices is based on DVFS Ondemand Governor and peripheral control by timeout event, such as turning off the LCD. In this paper, we propose a hybrid governor applying hardware supporting low power mode such as sleep mode to exploit the periodicity of fitness band task. In addition, we show hybrid governor outperforms in power consumption than conventional power management scheme of wearable devices based on Ondemand Governor through experiments.