• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.200-203
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• 2002

This paper presents Continuous-current mode of $S^4$-PFC(Single-Stage Single-switch Power Factor Correction) converter. Proposed converter operates in the continueous current mode(CCM) at full load and discontinuous current mode(DCM) at light load. So, characteristic of proposed converter is no bus voltage stress and Zero Voltage Switching(ZVS) using resonant auxiliary circuit. And. This paper presents characteristic of $S^4$-PFC converter and effect of circuit parameter of proposed converter through the input inductor, PFC capacitor's variation. All of these theory and characteristic verified through the experiment with a 72W(12V, 6A), $90^{kHz}$ prototype converter.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.469-477
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• 2012

This paper describes the characteristic analysis of ice impact force for the Arctic structure shape. In the present study an energy method has been used to predict the impact force during the ice-structure collision. This study also employs two concepts for reference contact area and normalized stress in analysis procedure. The influences of factors, such as impact velocity, full penetration depth, structure shape and ice floe size, are investigated. Full penetration occurs, particularly at lower impact velocity when ice thickness increase. But "typical size" ice floe does not expected ever to achieve full penetration during the impact procedure. The structure shape is the dominant factor in ice impact force characteristic. The results for various ice-structure collision scenarios are analyzed.

• Korean Security Journal
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• no.14
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• pp.261-283
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• 2007

In recent studies for explaining the causation of crime fear shows interest and effort in studies attempting microscopical individual level and macroscopical local level of sex, age, economic level, crime damage level and etc. However, in this study, it is considered that interest and analysis of individual on characteristics of these local level may has its difference depends on crime damage experience in the past, fragility precision of crime damage and interest on crime relating information and processed positive analysis on characteristics of individual and relation of crime fear on individual level before making an attempt of connecting microscopical level and macroscopical level. Therefore, the purpose of this study is on positive verification of how people feel about crime fear depends on individual's characteristic and also how much effect would they receive. As the result of this study, it is shown that first, population statistical characteristics that crime damage experience is statistically meaningful of its difference of each group are age, status of marriage, final education status and residential area and for the fragility precision of crime damage was sex and status of marriage and for the interest about the crime relating information has meaningful difference statistically of each group depends on sex, age, final education status, income of the house and location of residential area. Second, after processing correlation analysis on individual characteristic primary factor and crime fear, the result of 3 primary factor independent variable all shows statistically meaningful correlation with crime fear and especially fragility primary factor on crime damage showed the most high correlation with crime fear. Lastly, fragility of crime damage, interest on crime information and crime damage experience has effected as characteristics of individual and especially fragility of crime damage which the person thought to be the most fragility on crime damage out of these individual characteristic primary factor showed to have the most effecting primary factor.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2044-2049
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• 2007

In order to predict the thermal radiation induced from alumina particle cloud in the plume of solid propellant motor, view factor method is applied to space shuttle SRB and the result is compared with that of monte carlo method. For this purpose, radiative characteristics, such as particle cloud temperature distribution, effective emissivity or emissive power of particle cloud are studied. In the case of effective emissivity, inverse wavelength method is applied and plume reduction characteristic length is used for emissive power distribution. As a result, thermal radiation using view factor method gives more conservative results than that using monte carlo method. So it can be used for preliminary design of thermal protection system.

• Journal of the Korean Society of Costume
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• v.54 no.3
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• pp.73-85
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• 2004

The purpose of this study was to investigate the characteristic and sensibility of Japanism fashion designs which represented by Japanese designers and Western designers. The stimulus were 29 pictures of contemporary fashion designs which represented the Japanism style fashion designs from fashion collections. The data were analyzed by Cluster analysis, Factor analysis, Multidimensional Scaling Method and Regression Analysis. The specific objectives were as follows ; 1) As result of design analysis, Japanism fashion sensibility is unique and good-looking. 2) As result of the factor analysis. 4 factors which are Attractiveness, Attention, Maturity and Hardness and softness. 3) According to sensibility positioning, The Japanism fashion design was classified by Decorative-Simple, Hard-Soft. 4) As result of the Regression Analysis, The preference of Japanism fashion design was related to attractive factor. 5) As result of the Regression Analysis. The buying desirable of Japanism fashion design was related to attractive, attentive and mature factor.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2035_2036
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• 2009

This paper is purpose to understand the dissipation factor properties of the oil-filled large transformer according to the oil filtering. In order to know the insulation characteristic change by insulating oil filtering, we carried out the insulation diagnostic test for the same transformer before oil filtering and after. The insulation diagnosis tests are consist of the megger, the polarization index, the AC current test, the dissipation factor test and the partial discharge test, Especially we took notice of dissipation factor change, we analyzed and made a comparison of the two cases test result.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.103-106
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• 2007

This paper presents single-phase SRM drive system with single-stage high power factor and low torque ripple. Single-phase SRM has simple mechanical and electrical structure, robust and high speed operation characteristic. But conventional SRM drive with diode bridge rectifier and filter capacitor has a low power factor because of short charge time of capacitor. Therefore, this paper presents a novel single-phase SRM drive with single-stage structure circuit, which can improve the power factor and reduce peak torque ripple. A novel switching topology is presented base on mathematical analysis. The novel drive method is verified by simulations and experiments.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.702-704
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• 2001

This paper investigates efficiency and power factor of Switched Reluctance Motor (SRM) using Finite Element Method considered driving circuit. The efficiency and power factor are calculated in Input terminal and Output terminal respectively. When calculating power factor, apparent power is obtained by effective voltage and current because SRM is operated by switching of driving circuit. Efficiency is calculated by mechanical output and active power. Finally, the characteristics of efficiency and power factor in three proposed models are compared due to the switching pattern.

• The Journal of the Acoustical Society of Korea
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• v.19 no.1E
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• pp.38-42
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• 2000

In this paper we studied the reduced subjective timbre space of time-varying tones as well as steady state tones. 45 modified test tones were constructed from the original violin tone in consideration of 4 physical factors: spectrum envelope, inharmonicity, time-varying spectrum and time reversal. The semantic differential (SD) method was used in the listening test. According to the factor analysis, the adjectives can be factorized into 4 groups. The first factor is characterized by the adjectives, 'free', 'broad', 'deep', 'rich', 'strong' and 'reverberant', the second by 'tenor', 'clear', 'bright', 'light' and 'sharp', the third by 'easy', 'smooth', and 'solid', the fourth by 'warm' and 'full'. The first factor, 'richness', seems to be dependent upon the time-varying characteristic of a tone. The second factor, 'sharpness', is shown to play an important role in a time-varying tone as well as in a steady state tone.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2150-2156
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• 2007

According as level of industry develops day after day, electricity load system of industry requires high level control, effectiveness and high efficiency. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting and electric heating system. But, problems that power factor deterioration and fast response of control, efficiency, harmonics and etc are still remain. Therefore, in this paper proposed an inverter systems with constant current regulation and power factor correction (PFC) circuit for lighting and beaconing of aerodromes. The effectiveness of the proposed system confirmed through experimental results of 10[kW] power supply system.