• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.286-297
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• 2016

This study proposes criteria for both optimal-shape and magnetizer-system designs to be used for a high-output spoke-type motor. The study also examines methods of reducing high-cogging torque and torque ripple, to prevent noise and vibration. The optimal design of the stator and rotor can be enhanced using both a response surface method and finite element method. In addition, a magnetizer system is optimally designed for the magnetization of permanent magnets for use in the motor. Finally, this study verifies that the proposed motor can efficiently replace interior permanent magnet synchronous motor in many industries.

• Journal of The Korea Institute of Healthcare Architecture
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• v.21 no.1
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• pp.67-76
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• 2015

Purpose : The current tactile walking surface indicators have not been easily accessible to blind and vision-impaired people due to unexpected variation of walking environment and walking behavior of transportation poor. Moreover, those indicators frequently cause the inconvenience to transportation users' walking. Thus, this study aims to investigate the improvement of tactile walking surface indicators, by comparing and analyzing findings from the relevant research. Results from this study contribute to suggest the better standard criteria of tactile walking surface indicators for transportation users, especially blind and vision-impaired people, the handicapped, the child and the elderly and weak, providing the secure and convenient circumstance for walking. Method : This study presents the problems about the standard criteria of tactile walking surface indicators via the examination of finding from the past studies. For example, we examine all standard criteria, focusing on shapes, colors and qualities of materials used for Tactile Walking Surface Indicators. Then, the present study suggests the improvement of standard, which apply to the current walking environment practically and reasonably. Results : To improve the current condition of tactile walking surface indicators, the analysis on international and domestic standard criteria need to be conducted. Findings from these analyses helps to suggest the better criteria for the interval between projecting points of tactile walking surface indicators, effective perceived range of walking road, and the brightness contrast between tactile walking surface indicators and finishing materials. Implication : The suggested standard criteria of tactile walking surface indicators need to be tested by transportation users, and the practical instructions of establishing tactile walking surface indicators should also be developed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.306-310
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• 2010

On account of small size and light weight, a high-speed machine is regarded as a key technology for many future applications of drive systems. In high-speed applications, permanent magnet synchronous motors have a number of merits such as high efficiency and high power density. Therefore, they are suitable for driving the air-blower of a fuel cell electric vehicle (FCEV) where space and energy savings are critical. Particularly, a surface-mounted permanent magnet synchronous motor (SPMSM) of them is mainly used as a high-speed machine. However, the motor has a fatal flaw due to a retaining can to maintain the mechanical integrity of a rotor assembly. The can results in the increase of magnetic air-gap length in the SPMSM. Thus, in this paper, an interior permanent magnet synchronous motor (IPMSM) is applied in order to drive the air-blower of FCEV instead of the SPMSM, and the experimental results of two models are compared to verify the capability of the IPMSM for high-speed applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.210-213
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• 2002

For insulation design of the superconducting transformer, many types of insulation tests should be carried out. To clarify the components of insulation for superconducting transformer, there are main four parts as 1ike that turn-to-turn interior of each primary and secondary windings, layer-to-layer between primary and secondary windings, and winding to grounded structures. The insulation components should meet the required withstand voltage of the system and enough safety factors must included. As the fundamental insulation characteristics, we tested surface flashover voltage of spacer that would place between the coils and would take the role of both cooling duct and insulator. The structure of spacer in practice vary depending on coil type, in this work we considered double pancake coil for the superconducting transformer. In this study we tested flashover voltages of several arrangement of spacer.

• Korean Institute of Interior Design Journal
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• v.20 no.3
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• pp.98-109
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• 2011

To interpret a change of discourse can be a method to understand architectural space in progress. With this idea, features of modern age which motivated sense of the contemporary were considered in this study and subsequently characteristics of contemporary space differentiated from the modern were researched. First of all, features of subject which provided a base of modern thoughts were contemplated. The word 'modern' is used in wide and various terms but basically its core conception consists of reason and universal rationality. The subject of the modem age has vision-centric features just like an ideal representation principle of perspective. Given the fact, it was confirmed that a position to become a right subject, that is, a position controlled by reason existed and that it was to guarantee subject a truth. However, the contemporary subject keeps changing with a purpose of escaping from modern characteristics. It presents a tendency to escape from rationalism of the modern age and Platonism of the ancient Greece which established a basis of western ideology. The subject-centered ideas came to focus on the structure and relationship firmed fundamentally in deep inside of subject. The contemporary subject which escaped from the stiffen ideas bears a meaning through events taking place on immanence surface and serialization. Also, the contemporary architectural space is considered to go abreast with the change and trend. In conclusion, this study proved that features of event-oriented architectural space based on the changing contemporary subject appear as process-based space, user-participated space and individual-cognition space and the like.

• Journal of the Korean housing association
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• v.18 no.1
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• pp.61-72
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• 2007

The purposes of this study were to summarize the concept of well-being and well-being apartment, to grasp the present condition of apartments which were introduced with well-being elements, and to find out the consumer preferences on well-being elements for apartment planning. Library and internet surveys were performed to summarize the concept of well-being and well-being apartment and to grasp the present condition of apartments which were introduced with well-being elements. Questionnaire survey was carried out from 2nd to 22nd of June 2005, to investigate the preferences on well-being elements for apartment planning. The respondents were 250 residents who are from thirties to fifties and living in urban area. As results, respondents think that 'living for health of body and mind' about concept of well-being and 'certificated apartments by green building rating system' or 'apartments introduced ecological factor' about concept of well-being apartment. They answered that 'yes' about 'Do you have intention to buy well-being apartment?'. The elements in aspect of complex planning having the preference were revealed that promenade for complex design, ecological garden or walking space for landscape design, outdoor exercise space for outdoor design, and security system for foundation equipment. The elements having the preference in aspect of public facilities were fitness room for sports & health facility and study room for cultural facility. The preferred elements in aspect of building and unit design were roof garden for building design, multi-functional room for unit floor plan, natural surface material for interior surface, ventilation system for indoor environment, control system for home automation, and food waste machine for home electronics.

• KIEAE Journal
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• v.16 no.4
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• pp.71-77
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• 2016

Purpose : The energy saving in a residential building (apartment) sector is known as one of the effective solution of energy reduction. In South Korea, the government has recently reinforced regulations associated with the energy performance of buildings. However, there is a lack of research on the methods for the energy performance diagnosis that is used to analyze the wall thermal performance of the existing apartments. Because a reliable diagnosis is necessary to save the building energy, this study analyzed wall thermal performance of an existing apartment in Seoul. Method : This paper applied two methods for analysis of the thermal insulation performance; HFM(Heat Flow Meter) method and ASTR(Air-Surface Temperature Ratio) method. The HFM method is suggested by ISO9869-1 code to measure the thermal performance. The ASTR method is proposed by this study for the simplified In-situ measurement and it uses three temperature data (interior wall surface, interior and exterior air) and the overall heat transfer coefficient. This study conducted the experiment of an existing apartment in Seoul using these methods and analyzed the results. Furthermore, the energy simulation tool of the building was used to suggest retrofit of the building based on the results of measurements. Result : The error rate of HFM method and ASTR method was analyzed in about 17 to 20%. As the results of comparison between the initial design values of the wall and the measured values, the 26% degradation of insulation thermal performance was measured. Lastly, the energy simulation tool of the building shows 10.8% energy savings in accordance with the construction of suggested retrofit.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.137-142
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• 2021

In recent years, permanent magnets such as IPM (Interior Permanent Magnet) motors or SPM (Surface Permanent Magnet) motors that can obtain high efficiency and power density by inserting rare earth permanent magnets into the rotor are used. Research on the used electric motor is being actively conducted. Since it uses a permanent magnet, it has the advantage of high efficiency and high power density compared to reluctance motors and induction motors, but by inserting a permanent magnet into the rotor, it operates at high speeds and decreases reliability due to demagnetization of the permanent magnets, and increases the cost of rare earth metals. In this paper, in accordance with the development of future technology that can replace rare-earth permanent magnet motors and technological preoccupation of rare-earth reduction type motors and de-rare-earth motors, switched reluctance motors that do not require permanent magnets (Switched Reluvtance Motors) Motor, SRM) to drive driving control. Using the 3-phase SRM library provided by the PSIM simulation program, we will study the driving and control system modeling of SRM using the rotor position information sensor.

• Nuclear Engineering and Technology
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• v.47 no.5
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• pp.523-533
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• 2015

Three-dimensional flow phenomena in a wire-wrapped 37-pin fuel assembly mock-up of a Japanese loop-type sodium-cooled fast reactor, Monju, were investigated with a numerical analysis using a general-purpose commercial computational fluid dynamics code, CFX. Complicated and vortical flow phenomena in the wire-wrapped 37-pin fuel assembly were captured by a Reynolds-averaged Navier-Stokes flow simulation using a shear stress transport turbulence model. The main purpose of the current study is to understand the three-dimensional complex flow phenomena in a wire-wrapped fuel assembly to support the license issue for the core design. Computational fluid dynamics results show good agreement with friction factor correlation models. The secondary flow in the corner and edge subchannels is much stronger than that in an interior subchannel. The axial velocity averaged in the corner and edge subchannels is higher than that averaged in the interior subchannels. Three-dimensional multiscale vortex structures start to be formed by an interaction between secondary flows around each wire-wrapped pin. Behavior of the large-scale vortex structures in the corner and edge subchannels is closely related to the relative position between the hexagonal duct wall and the helically wrapped wire spacer. The small-scale vortex is axially developed in the interior subchannels. Furthermore, a driving force on each wire spacer surface is closely related to the relative position between the hexagonal duct wall and the wire spacer.

• Journal of the Korea Institute of Building Construction
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• v.17 no.3
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• pp.227-234
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• 2017

This research analyzes the properties of mortar following the rise in water-cement ratio and applicability as an eco-friendly construction supply by using the mudflats of a dredged arena as a substitute for aggregate. The results of a experiment of the flow showed that the flow value decreases as the amount of mudflats increases. A test for chloride content showed that the chloride content increases with the amount of mudflats. In the compression of specimen mixed with mudflat and the testing of tensile strength, the strength weakened as the addition ratio of mudflats rose. However, with 14-day strength as the standard, most specimen showed more strength than the plain, and 14-day strength was higher than 28-day strength. It appears to be experimental error in the mixing process from the viscosity and cohesion of mudflats, and it is considered that there will be a need for an experiment on mixing methods of mudflats in the future. The compressive strength of this research was the strongest with 70% in water-cement ratio, and the tensile strength was strongest with 80% in water-cement ratio. In the evaluation of surface analysis, 70% water-cement ratio, which is finest in strength, mixing, and compactness, was selected to analyze the roughness of the surface, and the results showed that the surface became smoother as the addition ratio of mudflats increases. In conclusion, it appears that 70% water-cement ratio is the optimal mixing ratio for mortar and 10 to 30% addition ratio of mudflats the optimal ratio. It also appears that the application of interior finishing material like bricks and tiles and interior plastering material using the mudflats are possible.