• Journal of Information Processing Systems
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• v.1 no.1 s.1
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• pp.49-54
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• 2005

With the recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low power consumption wireless micro sensor nodes have become available. However, energy-efficient routing is one of the most important key technologies in wireless sensor networks as sensor nodes are highly energy-constrained. Therefore, many researchers have proposed routing protocols for sensor networks, especially cluster-based routing protocols, which have many advantages such as reduced control messages, bandwidth re-usability, and improved power control. Some protocols use information on the locations of sensor nodes to construct clusters efficiently. However, it is rare that all sensor nodes know their positions. In this article, we propose another cluster-based routing protocol for sensor networks. This protocol does not use information concerning the locations of sensor nodes, but uses the remaining energy of sensor networks and the desirable number of cluster heads according to the circumstances of the sensor networks. From performance simulation, we found that the proposed protocol shows better performance than the low-energy adaptive clustering hierarchy (LEACH).

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1069-1070
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• 2008

This paper presents a high efficient two-stage interleaved synchronous buck CMOS DC-DC converter. The proposed circuit has a fixed duty cycle as 0.5 by an added buck converter. And it causes the best ripple cancelation of the output current ripple. The proposed circuit was simulated by HSPICE with a standard CMOS $0.35{\mu}m$ process parameter.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.301-302
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• 2007

Maximum power consumption was up to 6,228kW in the summer of 2007 due to steady development of industry as well as increased demand of individual. Twenty fossil-Fired Thermal Power Plant for 500MW were underconstructed at present. KEPRI(Korea Electric Power Research Institute) manage 'Development of Advanced Fossil-Fired Thermal Power Generation System' project to construct high efficient power plant of 1000MW capacity for preparing increased demand of power. Design of control logic and data sampling were explained and high efficient control logic was simulated in detail in 'The Development of Next Generation Power Plant Instrument and Control System'(sub-project of 'Development of Advanced Fossil-Fired Thermal Power Generation System' project).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.302-305
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• 2007

In recent years, many researches on new storage media with high capacity and information are developing. For manufacture of optical storage with high capacity, the injection molding process is generally used. In order to increase the filling ratio of the injection molding structure, the injection molding process required for high injection pressure, packing pressure and temperature control of the mold. However, conventional injection molding process is difficult to increase the filling ratio using injection master with the range of several nanometers and high aspect ratio. In order to improve and increase filling ratio of nano-structure with high aspect ratio, the active temperature control of injection mold was used. Experimental conditions were used injection pressure, time and temperature. Consequently, by using the peltier device into injection mold, we carried out the efficient and active temperature control of mold at low cost.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.12
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• pp.1197-1202
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• 2009

We present a power-efficient driving scheme that consists of piezoelectric actuator and driver IC for AF (Auto-Focus) on ISM (Image Sensor Module). The piezoelectric actuator is more power-efficient than conventional voice coil motor actuator. And high power-efficiency driver IC is designed. So the proposed driving scheme using designed piezoelectric actuator and driver IC is more close to recent trend of green IT. The diver IC should guarantee fast and accurate performance. So, the optimum driving method and high accurate frequency synthesizer are proposed. The die area of designed driver IC is $2.0{\times}1.6mm^2$ and power consumption is 2.8mW.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.257-264
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• 2015

This paper proposes an adaptive RRT (Rapidly-exploring Random Tree) for path planning of high DOF multibody robotic system. For an efficient path planning in high-dimensional configuration space, the proposed algorithm adaptively selects the robot bodies depending on the complexity of path planning. Then, the RRT grows only using the DOFs corresponding with the selected bodies. Since the RRT is extended in the configuration space with adaptive dimensionality, the RRT can grow in the lower dimensional configuration space. Thus the adaptive RRT method executes a faster path planning and smaller DOF for a robot. We implement our algorithm for path planning of 19 DOF robot, AMIRO. The results from our simulations show that the adaptive RRT-based path planner is more efficient than the basic RRT-based path planner.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.215-217
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• 2007

This paper proposes the method to improve the charging speed of high voltage capacitor used in the portable medical device. The feedback control method with microprocessor was used to detect charging time and control charging voltage. The result shows that the proposed method is more efficient than only voltage check method with typical charging sequence control.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.45-49
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• 2013

High frequency system has been used for the purpose of skin care and obesity treatment, by high-frequency energy is applied to the human body generates deep heat. Conventional high frequency system could not selection control by depending on the body load fluctuations. Such as burns and side effects have been reported by system instability and then therapeutic effect is insufficient. During treatment, objective information about the status of the patient was no. Because of treatment methods are subjective, and so tailored treatments were impossible. In this paper, high frequency medical system with sinusoidal frequency characteristics without distortion of the Push pull switching scheme for pain relief therapy was designed. And control circuit that was designed by feedback using the output changes according to the body-load fluctuation. Last, power circuit for efficient control the heat generated from the hardware was proposed.

• Smart Structures and Systems
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• v.30 no.5
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• pp.537-544
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• 2022

The optimal design of structural composite materials is a research topic that attracts the attention of lots researchers. For many more thirty years, there has been increasing interest in the applications in all kinds of topics, which means taking advantage of fuzzy set theory, fuzzy analysis, and fuzzy control for designing high-performance and efficient structural systems is a fundamental concern for engineers, and many applications require the use of a systems approach to combine structural and active control systems. Therefore, an intelligent method can be designed based on the mitigation method, and by establishing the stable of the closed-loop fuzzy mitigation system, the behavior of the closed-loop fuzzy mitigation system can be accurately predicted. In this article, the intelligent algorithm and optimum design of fuzzy theory for structural control has been provided and demonstrated effective and efficient in practical engineering issues.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.1
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• pp.41-49
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• 2019

Purpose: After Mers breakout in 2015, major hospital in Korea have been renovated the emergency department to make a separate infection control zone for high-risk patient with potential infection and to improve a triage area and an entrance area for efficient patient evaluation. However, there are no specific design standards to reinforce infection control for patients and staffs safety. Therefore, it is important to establish of initial design factors in the triage and entrance area as a guideline. Methods: 5 cases which had been recently renovated are selected to analyze patient circulation and spatial composition in a triage area and an entrance area. The partial floor plans of each case are represented as bubble diagrams to help understanding of different patient circulation flows. Based on this analysis, significant design factors which should be considered in planning stage for infection control have been extracted. Results: 13 design factors are established. Using these design factors, patient circulation diagram is generated to provide an optimized suggestion for efficient infection control. Implications: This suggestion provides basic databases to start to establish design guideline in the triage area and the entrance area to minimize infection spreading in the emergency department.