• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.31-32
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• 2012

This paper presents a new design of magnetic bearing structure for application in Nuclear Power Plant (NPP). The proposed design includes so-called saturated coils which is used to generate the bias flux for bearing almost the whole mass of the rotor, and so-called linear auxiliary coil controlled to stabilize the suspension. The saturated coil is considered as an special electromagnet which is controlled to operate in the region of magnetic saturation in order to minimize the bias current as well as to enhance the magnetic flux density. This strategy will result in a very compact size of magnetic bearing as well as increasing the speed of the response of the current controller. The novel structure is expected to be applied to design very high power gas turbine generator of next generation of fast reactor in which the mass of rotor can reach 50 tons. The total power of the NPP can reach 2,000 MW. Moreover, the issue of arc occurrence between coils is also discussed and two solutions are proposed.

• Journal of the Korean Solar Energy Society
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• v.37 no.2
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• pp.13-22
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• 2017

Two-step water splitting thermochemical cycle with $CeO_2/ZrO_2$ foam device was investigated by using a solar simulator composed of 2.5 kW Xe-Arc lamp and mirror reflector. The hydrogen production of $CeO_2/ZrO_2$ foam device depending on heat recovery of Thermal-Reduction step and Water-Decomposition step was analyzed, and the hydrogen production of $CeO_2/ZrO_2$ and $NiFe_2O_4/ZrO_2$ foam devices was compared. Resultantly, the quantity of hydrogen generation increased by 52.02% when the carrier gas of Thermal-Reduction step is preheated to $200^{\circ}C$ and, when the $N_2/steam$ is preheated to $200^{\circ}C$ in the Water-Decomposition step, the quantity of hydrogen generation increased by 35.85%. Therefore, it is important to retrieve the heat from the highly heated gases discharged from each of the reaction spaces in order to increase the reaction temperature of each of the stages and thereby increasing the quantity of hydrogen generated through this.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.572-578
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• 1985

A composite gear with involute-circular are tooth profile and a tooth profile of the rack to cut this gear are theoretictically obtained. The composite gear has involute tooth profile in the vicinity of pitch point and has circular arc tooth profiles at addendum adn dedendum. The contact ratio(M$_{c}$), chordal tooth thickness (chordal tip tooth thickness S$_{t}$, chordal root tooth thickness S$_{t}$) of the composite gear are compared with those of involute gear. When module, number of teeth and pressure angle eqaul, S$_{t}$ of composite gear is much larger than that of involute gear. Under the same conditions, S/sib t/ and M$_{c}$ of composite gear become smaller than those of involute gear.lute gear.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.551-560
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• 2003

This paper summarizes development of a 10KW stand-alone power processing unit for 5KW SOFC-low voltage battery hybrid fuel cell power generation system. The power processing unit Includes three parts a high frequency DC-DC converter boosts low fuel cell voltage, a DC-AC inverter converts a dc voltage into a regulated ac voltage and a bidirectional DC-DC converter charges or discharges the battery. The converter topology, design, control method, and experimental result arc presented to meet the specifications such as efficiency of 90% and cost of $40/KW laid down for the "2003 Future Energy Challenge Competition" organized by the U.S. Department of Energy and IEEE. and IEEE.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.55-63
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• 2017

Due to spatial problems and system size,conventional measurement methods used to acquire the information needed for existing electrical energy and management have been limited to new buildings or areas where replacement is possible. This electric load management method is problematic when applying it to energy and safety management of vulnerable areas or existing homes or offices. The problem with installing a measurement module in every branch is that the system is too large. Even if the measurement module is installed, the type of load is not recognized, and efficient management is not performed. In particular, it is very difficult to apply it to traditional markets and backward facilities in Korea. In this paper, we apply NIALM technology and arc detection technology to solve these problems and verify the feasibility of NIALM for normal arc generation. Also, based on the verification results, we propose a new smart home safety management system that can effectively manage electrical safety and that can be applied to conventional market and existing home safety management systems. The proposed system conducts a comparative performance test with an existing safety management system. In addition, it achieves 95% or more load recognition for four loads, which is impossible in 40% of the existing systems, and the arc detection function was confirmed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1606-1611
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• 2008

Recently, The diagnosis techniques of electric facilities are developed on live line. This paper describes the discharge characteristics of polymer insulator(EPDM A type). Keeping the facilities in good working order, the goal of this paper will provide the information to enable user to easily judge conditions of facilities on the spot. The performance of polymer insulator is assessed from the KS C IEC 60270 and CEA LWIWG-01(96)(Tracking Wheel Test). As the results, UV generation patterns of polymer insulator grow like a jellyfish shape follow the ramping voltage. Discharging UVs are detected at about 31.25% of breakdown voltage. Just then, dimension of UV image is about $0.84cm^{2}$. The dimension of max. UV image is about $297.4cm^{2}$ at $160kV(V_{bd})$. The position of UV generation due to surface discharge of polymer insulator is the center of insulator in the early, then moved the ground side and the last, UV image moved through the junction part of source side. Surface of aged polymer insulator is cracked and faded due to arc. UV absorption spectrum of polymer insulator are appeared the C-H bond of scissoring vib. at $1014cm^{-1}$ and C=O bond of recombination structure. Also, recombined UV absorption peak such as C-H, N-H, and O-H is detected at the $3321cm^{-1}$. Through the paper, there are inspection data which are the relations between surface discharge of polymer insulator and UV detecting image.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.745-754
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• 2013

An efficient urban outdoor localization and navigation system is proposed for car-like robots. First an accurate outdoor localization method is suggested using line/arc features and 2.5D map matching with LRFs (Laser Range Finders), which can reduce the number of singular cases and increase accuracy. Also, path generation, path tracking, and path modification algorithms are proposed for navigation. All these algorithms are implemented on an electric scooter to construct an autonomous urban outdoor localization and navigation system. Experiments reveal the practicality of the proposed system.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.34-35
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• 2011

전기화재의 주요 원인 중 하나인 아크를 검출 및 차단하기 위한 장치로서 아크차단기(AFCI)가 사용되고 있으며 이는 UL1699에서 규정되고 있다. 본 논문에서는 UL1699에서 정의되는 직렬아크의 발생 조건에 따라 아크발생장치를 이용하여 아크를 발생시키고 부하를 변화시켜 아크가 일어날 경우의 교류전원의 특성을 해석하였다.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.11
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• pp.66-75
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• 2007

To prevent an insulator failure, an automatic cleaning and inspection robot was developed for suspension insulator strings. The robot autonomously moves along the insulator string using the clamps installed on its two moving frames. Especially, unlike the existing cleaning robots using jets of water, the robot system adopts a dry cleaning method using rotating brushes and a circular motion guide. In addition, a mechanized brush bristles and a voltage-balancing contactor are devised to increase cleaning efficiency and to prevent arc generation under live-line conditions, respectively. We confirmed its effectiveness through experiments.

• Knowledge Management Research
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• v.3 no.2
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• pp.49-70
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• 2002

The purpose of this study is to investigate the process and its influencing factors of technological capability building in a small and medium-sized capital goods sector. This paper first reviews the influencing factors of accumulating technological capability-technology trajectory, technology sources, technological capability, technological learning, technology strategy, and entrepreneurship. The paper then presents the integrative model of technological capability building. The experience of Mirae Corporation, the first generation of venture company in Korea, is also discussed as a case in point to analyse the process of technological capability building in a small and medium-sized capital goods company. Finally, the implications and limitations of the study arc discussed.