• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2015.08a
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• pp.117-120
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• 2015

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.165-170
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• 2015

In this paper, The strength and driving characteristics of it were investigated according to developing the traction motor for 8200 electric locomotive series. For this purpose, Flux density strength was analyzed and then structural strength was investigated such as a stator frame, design of the rotor shaft bearing according to the design process. In addition, the traction motor operating point was analyzed according to slip frequency variation at a power source frequency. As the results of analysis on torque-speed characteristic curve, we was confirmed that traction motor was controlled as torque control prior to motor speed 1610[rpm], power control between 1610[rpm] and 2500[rpm] and breakdown torque control more than motor speed 2500[rpm].

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2938-2940
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• 2011

Novel C-aryl glucoside SGLT2 inhibitors containing triazine motif were designed and synthesized for biological evaluation. Among the compounds assayed, triazine containing methoxy moiety 18 demonstrated the best in vitro inhibitory activity against hSGLT2 in this series to date ($IC_{50}$ = 24.9 nM).

• International Journal of Costume and Fashion
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• v.6 no.1
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• pp.20-29
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• 2006

Once people thought the phenomenon of 'Ha-Han' was only a vogue of young people pursuing oddity. However, when Korean TV series, Korean food, Korean movies and their music penetrated into our life and appeared on TV screens and fashionable magazines, all aspects influence of Korean wave finally arouse people's attention. 'Ha-Han-Zu' is a group of young people who pursue Korean popular culture even imitating their dressing, thoughts and behaviors. This article takes China the original place of Korean wave's popularity as focus, observes the reflection of Chinese to Korean popular culture and discusses the culture exchange phases of Korean wave as the center of popular culture. It can be more detailed that it bases on HOT wave from 1998 to 2004 and analyzes of popular TV series, observes reflects of 'Ha-Han-Zu' to Korean culture, discusses the acceptance to Korean popular culture and what kind of active reflection consumption giving to culture exchange.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.173-181
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• 2017

In this paper, the bifurcation criteria for inductive power transfer (IPT) systems is suggested considering the inductive power pad losses. The bifurcation criteria for series-series (SS) and series-parallel (SP) topologies are derived in terms of the main parameters of the IPT system. For deriving precise criteria, power pad resistance is obtained by copper loss calculation and core loss analysis. Utilizing the suggested criteria, possibility of bifurcation occurrence can be predicted in the design process. In order to verify the proposed criteria, 50 W IPT laboratory prototype is fabricated and the feasibilities of the switching frequency and AC load resistance shift to escape from bifurcation are identified.

• Bulletin of the Korean Chemical Society
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• v.18 no.2
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• pp.161-164
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• 1997

Kinetic studies are carried out on the reactions of 1- and 2-naphthylmethyl arenesulfonates with anilines in acetonitrile at 25.0 ℃. The rates are faster for the 2-naphthylmethyl series than for the corresponding 1-naphthylmethyl series suggesting that there is a greater stabilization of positive charge development in the TS at the arylmethyl reaction center carbon for the former. The sign and magnitude of ρxz (=-0.12) are similar to those of the benzylic series. Thus, benzyl, 1- and 2-naphthylmethyl derivatives belong to a class of compounds which react with aniline nucleophiles through a relatively loose SN2 TS. Kinetic secondary deuterium isotope effects indicated that a stronger nucleophile and nucleofuge lead to a later TS as the definition of ρxz requires.

• Korean Journal of Remote Sensing
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• v.29 no.3
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• pp.315-324
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• 2013

Spatial information of snow cover and depth distribution is a key component for snowmelt runoff modeling. Wide snow cover areas can be extracted from NOAA AVHRR or Terra MODIS satellite images. In this study eight sets of annual snow cover data (1997-2006) in two mountainous watersheds (A: Chungju-Dam and B: Soyanggang-Dam) were extracted using NOAA AVHRR images. The distribution of snow depth within the Snow Cover Area (SCA) was generated using snowfall data from ground meteorological observation stations. Snow depletion characteristics for the two watersheds were analyzed snow distribution time series data. The decreased pattern of SCA can be expressed as a logarithmic function; the determination coefficients were 0.62 and 0.68 for the A and B watersheds, respectively. The SCA decreased over 70% within 10 days from the time of maximum SCA.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.14-19
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• 2008

The paper presents an intelligent time series model to predict uncertain electricity market price in the deregulated industry environment. Since the price of electricity in a deregulated market is very volatile, it is difficult to estimate an accurate market price using historically observed data. The parameter of an intelligent time series model is obtained based on the simultaneous perturbation stochastic approximation (SPSA). The SPSA is flexible to use in high dimensional systems. Since prediction models have their modeling error, an error compensator is developed as compensation. The SPSA based intelligent model is applied to predict the electricity market price in the Pennsylvania-New Jersey-Maryland (PJM) electricity market.

• School Mathematics
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• v.16 no.2
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• pp.317-334
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• 2014

The purpose of this study is to grasp pre-service secondary teachers' understanding-realities for Taylor series convergence conceptions and to examine a teaching way using GeoGebra based on the understanding-realities. In this study, most pre-service teachers have abilities to calculate the Taylor series and radius of convergence, but they are vulnerable to conceptual problems which give meaning of the equality between a given function and its Taylor series at any point. Also they have some weakness in determining the change of radius of convergence according to the change of Taylor series' center. To improve their weakness, we explore a teaching way using dynamic and CAS functionality of GeoGebra. This study is expected to improve the pedagogical content knowledge of pre-service secondary mathematics teachers for infinite series treated in high school mathematics.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.301-303
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• 2001

In this paper we present a Capacitor Charging Power Supply (CCPS) using a series-resonant three-level inverter topology to improve voltage regulation and use semiconductor switches having low blocking voltage capability such as MOSFETs. This inverter can be operated with two modes, Full Power Mode (FPM) and Half Power Mode (HPM). In FPM inverter supplies the high frequency step up transformer with full DC-link voltage and in HPM with half DC-link voltage. HPM switching method will be adopted when CCPS output voltage reaches the preset target value and operates in refresh mode-charge is maintained on the capacitor. In this topology each semiconductor devices blocks a half of the DC-link voltage[2]. A 15kW, 30kV CCPS has been built and will be tested for an electric precipitator application. The CCPS operates from an input voltage of 500VDC and has a variable output voltage between 10 to 30kV and 1kHz repetition rate at 44nF capacitive load [3]. A resonant frequency of 67.9kHz was selected and a voltage regulation of $0.83\%$ has been achieved through the use of half power mode without using the forced cut off the switch current [1]. The theory of operation, circuit topology and test results are given.