• Journal of the Korean housing association
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• v.26 no.5
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• pp.143-152
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• 2015

The purpose of this study was to analyze the usage characteristics and the role of spatial and social psychology of open spaces in urban neighborhoods. The survey for this study was conducted on 318 residents in Gyungsan. For analysis, the frequencies and means were calculated, the chi-square test, t-test, and analysis of variance were performed. Survey results revealed that, first, not only the preferred open space type but also the usage characteristics by gender were different. The tendency for males was to visit open spaces to exercise and to stay for longer than one hour. However, the females visited open spaces to care for their children and meet friends or neighbors. They also visited more often than males but stayed for a shorter time. Second, females tended to consider the open space as a place for rest and leisure. Females valued the social psychology aspects of the open space function. Third, regarding the spacial role of open space in urban neighborhoods, study participants believed that the waterside parks improve the quality of life, but were concerned for the safety of children. Considering the social psychology role of open spaces, study participants regarded the waterside parks as improving emotional health. Particularly, they believed the waterside parks played a greater role in daily life as a place for meeting, resting, and leisure than other open space types such as playground, children's parks, and sport parks.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.190-199
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• 2014

In the last years, fault problem in power electronics has been more and more investigated both from theoretical and practical point of view. The fault problem can cause equipment failure, data and economical losses. And the analyze system require to ensure fault problem and also rectify failures. The current errors on these faults are applied for identified type of faults. This paper presents technique to detection and identification faults in three-phase voltage source inverter (VSI) by using time-frequency distribution (TFD). TFD capable represent time frequency representation (TFR) in temporal and spectral information. Based on TFR, signal parameters are calculated such as instantaneous average current, instantaneous root mean square current, instantaneous fundamental root mean square current and, instantaneous total current waveform distortion. From on results, the detection of VSI faults could be determined based on characteristic of parameter estimation. And also concluded that the fault detection is capable of identifying the type of inverter fault and can reduce cost maintenance.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.1
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• pp.45-55
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• 2015

The purpose of this study was to compare the science philosophical views and instruction strategies for open-inquiry between teachers of science-gifted and teachers of general students. The subjects were 45 teachers of science-gifted and 45 teachers of general students. The major results of this study were as follows: First, there was no differences on the science philosophical views between teachers of science-gifted and teachers of general students by chi-square tests (p<.05). Second, there were no differences on how task assignments, how to guide exploration data, and how to write reports between teachers of science-gifted and teachers of general students (p<.05). But there was meaningful differences on how to proceed with exploration activities between teachers of science-gifted and teachers of general students (p<.05). It is implied that this the results of this investigation will help the focus of future efforts to promote more adequate the science philosophical views and instruction strategies for open-inquiry in teachers of science-gifted.

• East Asian mathematical journal
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• v.32 no.4
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• pp.545-563
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• 2016

The aim of this study was to observe processes and implication to a given program for the 20 gifted children grade 5 by making the number from 1 to 100 with natural numbers 4,4,9 and 9. Revelation of creativity, mathematical tendency of students and meaningful responses were observed by the qualitative records of this game activity and the analysis of result. The major result of a study is as follows: The mathematical creativities of students were revealed and developed by this activity. And the mathematical attitude were changed and developed, so student could actively participate. And students could experience collaborative and social composition learning by presentations and discussion, competition with a permissive atmosphere and open-game rule. It was meaningful that mathematical ideas (negative number, square root, factorial, [x]: the largest integer not greater than x, absolute value, percent, exponent, logarithm etc.) were suggested and motivated by students themselves.

• Transactions of Materials Processing
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• v.4 no.2
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• pp.141-150
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• 1995

The purpose of the open die press forging is to maximize the internal deformation for better structural homogeneity and center-line consolidation in case of the ingot. A two and three dimensional viscoplastic finite element analysis is carried out for the plate, cylinder and square forging with the flat die in order to study the forging effects during the process. Effect of width, height reduction, and die staggering are studied through simulation of the process. Thus favorable working conditions are suggested for better and more disirable product quality.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.5
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• pp.537-551
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• 2017

In this paper, a two-phase flow solver $HiFoam^{(R)}$ has been developed based on the $OpenFOAM^{(R)}$ to predict resistance of a ship in calm water. The VOF method of $OpenFOAM^{(R)}$ was reviewed and a simple flux limiter was introduced to enhance the robustness of the solver. The procedure for predicting ship motion was modified by introducing Quasi-Steady Fluid-Body Interaction (QS-FBI) with least square regression to improve the efficiency. Other minor factors were considered as well in terms of the efficiency and robustness. The HiFoam was applied to KCS and JBC simulations to validate its efficiency and accuracy by comparing the results to experimental data and STAR-CCM+. The $HiFoam^{(R)}$ was also applied to various ships and it showed good agreements to the experimental data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.559-562
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• 2000

In this paper, coplanar waveguide fed antennas (CPWFAs) insetting two slits to boundary of the square microstrip patch are presented. These slits play roles in not only lowering a resonant frequency but also fine-tuning for the proposed antenna together with open stub of CPW feed line. The CPWFAs were designed and manufactured using microwave dielectrics (Al,Mg)TaO$_2$ having high dielectric-constant ($\varepsilon$r=20). The return loss and input impedance of the CPWFAs were investigated in terms of the slit length and open stub length of CPW feed line. It is shown that a resonant frequency decreases as the slit length increases.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.94-101
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• 2004

This study aimed at providing suggestions in designing open space so that parks and bordering facilities are well related to each other in terms of the visual access and human activities. The design survey was conducted in the center of Osaka City, using parks there as the study material. The relation between parks and their bordering facilities was evaluated in terms of the visual access and human activities. Through the results of this study, as the design methods for improving relations between parks and their bordering facilities, unified design and creation of square in the boundary area between them, placing access paths to facilities in parks, and planting trees to create Vista, Screen, and Framework landscapes are of great importance.

• Journal of Power Electronics
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• v.13 no.6
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• pp.985-990
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• 2013

This paper proposes a novel fault diagnosis scheme using parameter estimation of the stator resistance, especially in the case of the open-phase faults of PMSM drives. The stator resistance of PMSMs can be estimated by the recursive least square (RLS) algorithm in real time. Fault diagnosis is achieved by analyzing the estimated stator resistance of each phase according to the fault condition. The proposed fault diagnosis scheme is implemented without any extra devices. Moreover, the estimated parameter information can be used to improve the control performance. The feasibility of the proposed fault diagnosis scheme is verified by simulation and experimental results.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.35-49
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• 2021

This paper presents a direct numerical simulation of turbulent flows over a bump in an open channel to examine the turbulence characteristics near divergent waves emanating from the bump and to investigate the interaction of the turbulences with the divergent waves. To verify the reliability of the simulations, the mean velocity profile and root-mean-square of velocity fluctuations are compared with previous data. The anisotropic invariant maps show that the ratio of the streamwise to spanwise velocity fluctuations plays an important role in characterizing the anisotropic nature of the separated shear layer behind the bump in the vicinity of the free surface. The vortex identification discloses a large-scale streamwise vortical structure from the mean velocity field and a cluster of small coherent structures from the instantaneous velocity field, which are responsible for the anisotropic characteristics of the turbulence beneath the free surface.