• Progress in Superconductivity and Cryogenics
• /
• v.1 no.1
• /
• pp.1-6
• /
• 1999

The microstructures of top seed mult processde $\textrm{YBa}_2\textrm{Cu}_3\textrm{O}_7$.$\delta$ single crystal were studied. Although shape of the seed was not faceted. the growth shape of Y123 single crystal was faceted. It was observed that Y211 phases were trapped in specific spaces of the faceted region. From the microstructural investigation. it was suggested that the segregation of Y211 is due to the difference of growth rates in crystal direction. When a single crystal was grown by the single seed with stepped multi surfaces. a microstrue was grown from multi-seed. The microstructure show the possibility of multi-seed growth. Corn kernel like structure without Y211 phase was observed and seemed to be formed by the diffusion reaction between Y211 phase in crystal and liquid wetted on the crystal. the diagonal line on Y123 crystal was observed that it was formed by the corn kernel like structure.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1921_1922
• /
• 2009

According to recent researches, apparent power in non-sinusoidal single phase system can be represented with geometric algebra. In this paper, the geometric algebra is applied to apparent power defined in a multi-line system having transmission lines with frequency-dependent resistances under non-sinusoidal conditions.

• Journal of the Korean Statistical Society
• /
• v.8 no.1
• /
• pp.65-83
• /
• 1979

The general description concerning the multi-line systems with the switching rules have been presented by Ahn. In this paper we derive some steady state probabilities for three mainly different kinds of systems. We assume that all of the systems are to have poisson input with the finite mean $1/\lambda$ and two servers with the negative exponentional service distribution where each has its own mean $1/u_i$. The notations follow the paper (Ahn, 1979).

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.11
• /
• pp.2267-2272
• /
• 2009

The six-port direct conversion receiver front-end that is comprised of a carrier recovery and a phase shifter, which gets the same structure with six-port phase correlator using the multi-layer coupled line, was designed and fabricated in this paper. The six-port element that is comprised of the power divider and the hybrid coupler is designed by multi-layer coupled line structure. The multi-coupled structure is utilized as the basic structure in receiver phase correlator, carrier recovery circuit and phase shifter. The receiver front-end with the same multi-layer coupled line structure for the receiver elements shows the simple structure and no difficulty in integration. The fabricated multi-layer coupled six-port receiver front-end re-generates the carrier signal with a constant phase and demodulates the PSK transmission signal.

• Proceedings of the KSR Conference
• /
• 2000.11a
• /
• pp.77-85
• /
• 2000

The railway system is composed of large scale infrastructures and high-cost trains. For planning and analyzing this kind of complex system, simulation method can be used for efficient tool. In this research, we review basic simulation programming models and present a modeling for the elements of railway system such as rail-line infrastructure, train, time table and operational route. Additionally, some considerations on the development of multi-train traffic simulator for KyongBu-line are discussed.

• Proceedings of the IEEK Conference
• /
• 2000.07a
• /
• pp.132-135
• /
• 2000

In this paper, we propose to exploit a multi-code CDMA scheme for power line communication (PLC) systems, and its performance on non-Gaussian impulse and harmonic noises is presented. The proposed multi-code CDMA scheme utilizes convolutional coding and block interleaving to combat with the non-Gaussian noises, and simulation results indicate effective alleviation of these noises, and thus significant bit error rate improvement by the proposed scheme even under strict restriction of frequency band allowed in PLC systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.88.3-88
• /
• 2001

In this paper, an on-line multi-sensor visual inspection technique for seamless steel pipe´s straightness is developed. The basic principle of the visual measuring method is detailed. The modeling of visual sensor, measurement system and data processing are presented. In order to test the accuracy of the multi-sensor visual inspection, an experiment inspecting the straightness of a 1500mm long seamless steel pipe is made. The experiment results show that the visual inspection technique can achieve on-line measurement and offers high precision and stability.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.38 no.4
• /
• pp.401-410
• /
• 2001

An adaptive Odd/Even Multi-shell Median Filter(Adaptive O/E MMF) is proposed by using a adaptive threshold strategy and odd/even multishells. This algorithm was verified in MATLAB and implemented on FPGA. The performance of the algorithm is evaluated by adding impulse noise and line missing into well-known images. A proposed adaptive threshold strategy may reduce the computation time and redundant arrangement. odd and even multishells can recover line missing of vertical and diagonal directions respectively Therefore, the algorithm proposed in this work can be effectively used in real time image processing applications.

• Atmosphere
• /
• v.21 no.2
• /
• pp.151-162
• /
• 2011

One-layer solar radiation(GWNU; Gangneung-Wonju National University) model is developed in order to resolve the lack of vertical observations and fast calculation with high resolution. GWNU model is based on IQBAL(Iqbal, 1983) and NREL(National Renewable Energy Laboratory) methods and corrected by precise multi-layer LBL(Line-by-line) model. Input data were used 42 atmospheric profiles from Garand et al.(2001) for calculation of global radiation by the Multi-layer and one-layer solar radiation models. GWNU model has error of about -0.10% compared with LBL model while IQBAL and NREL models have errors of about -3.92 and -2.57%, respectively. Global solar radiation was calculated by corrected GWNU solar model with satellites(MODIS, OMI and MTSAT-1R), RDPS model prediction data in Korea peninsula in 2009, and the results were compared to surface solar radiation observed by 22 KMA solar sites. All models have correlation($R^2$) of 0.91 with the observed hourly solar radiation, and root mean square errors of IQBAL, NREL and GWNU models are 69.16, 69.74 and $67.53W/m^2$, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.6
• /
• pp.910-915
• /
• 2012

In this paper we propose multi-grounded neutral design method which was considered of transferred transient overvoltage when line to neutral fault occurs. Specially, In order to confirm the actual transient overvoltage magnitude which occurs on neutral line, we considered some screening(shielding) effects. The screening coefficient was deducted from field test results and calculation in a distribution line which is identical with an actual power line. The purpose of this paper is to attempt to suggest the guidance for grounding skystem design considering limitation of overvoltage for LV side in IEC 61936. The result is based on EMTP simulation and real field faults situation in distribution lines.