• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.6
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• pp.42-50
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• 1996

이 논문은 step기둥의 자유진동 및 좌굴하중에 관한 연구이다. 축하중을 받는 변단면 기둥의 자유진동을 지배하는 편미분방정식을 이용하여 축하중을 받는 step기둥의 자유진동을 지배하는 상미분방정식을 유도하였다. 또한 이 자유진동을 지배하는 미분방정식을 이용하여 step기둥의 좌굴하중을 지배하는 상미분방정식을 유도하였다. 유도된 미분방정식들을 Heun방법과 Regula-Falsi방법을 이용하여 고유진동수 및 좌굴하중을 산출할 수 있는 수치해석방법을 개발하였다. 실제 수치해석 예에서는 2개의 step구간을 갖는 회전-회전, 회전-고정, 고정-고정 기둥에 대한 무차원 고유진동수화 무차원변수들과의 관계 및 무차원 좌굴하중과 무차원 변수들과의 관계를 그림에 나타내었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1249-1253
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• 2001

Numerical analysis is sometimes used to solve the problems in the engineering and natural science fields. On this reason, the faster, more practical system in computing the numerical solution is required. This paper deals with the numerical evaluation of various numerical integration methods which is frequently used in the engineering fields. This paper choices four integration methods such as Euler method, Heun's method, Runge-Kutta method and Gill's method for evaluating the each integration method. In numerical examples, the free vibration problem on an elastic foundation is chosen. As the numerical results, the natural frequencies and the running time are obtained, and these results are compared to examine the practicality of integration methods.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.6
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• pp.73-79
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• 2009

For the shake of control for movement object, control theory like neural network, nonlinear model predictive control(NMPC) is realized on digital high speed computer. Predictor of flight control system(FCS) based nonlinear model predictive control has to be satisfied with response for hard real-time to perform applications on each module in the FCS. Simultaneously, It gives a serious consideration accuracy to give full play to FCS's performance. Error of mathematical aspect affects realization of whole algorithm. But factors of bring mathematical error is not considered to calculate final accuracy on parameter of predictor. In this paper, Predictor was made using load control model on the digital computer for design FCS at hard real-time and is shown response time on realization algorithm. And is shown realization algorithm of high effective predictor over the accuracy. The predictor was realized on the load control model using Euler method, Heun method, Runge-Kutta and Taylor method.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.51-60
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• 2012

In this paper, we provide the analysis of device model and method between device models for compatible M&S V&V of the NetSPIN. First of all, we analysis features, structure, and classification of the NetSPIN. The second, as a part of reliable V&V process, we analysis network system modeling process, correlation between device modeling process for M&S of the NetSPIN. The third, we suggest making a kind of pool of reference model and module of devices for the increase factor of reuse between device model. We also, at the point view of M&S V&V, conclude that there is the validity of the fidelity in device modeling process. Through the analysis of the NetSPIN device model and suggestion of the method for higher compatibility between device modes, the development process of device model be clearly understood. Also we present the effective method of the development for reliable device mode as the point of V&V.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.153-156
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• 2005

Surface dry condition examination method on the KS F 2504(Testing method for specific gravity and absorption of fine aggregate) has dim detail prescriptions which can cause different ways of understanding based on one's convinence, not on correct means of rule. So we investigate the problems about the inconsistency on decisioing surface dry condition at management examination in the lab and scene. In conclusion, free-falling method is easier and faster than self-weight method. And we also found that the most important face on decisioning surface dry is compacting factor of tamping rod.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.998-1004
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• 2005

U.J.S.(Ultra Jetting System) is a new ground improvement method registered as a Utility Model No.0205798, which has fundamentally improved the existing jetting method of J.S.P.(Jumbo Special Pattern System). In this study, the uniaxial compressive strengths of improved soil-grout structures by U.J.S. and J.S.P. which have been conducted on the construction site are compared. Also, the differences between the U.J.S. and J.S.P. are analyzed by considering the role of the auger bit, the injection distance measured from the axis of boring tubes, and angle of injection measured from the horizontal. The specimens of soil-grout structures are taken from the improved soils by using the U.J.S. and J.S.P. The uniaxial tests for the samples are conducted after the curing period of 28 days. The uniaxial compressive strengths and the coefficients of elasticity of surface and distance from the axis of boring. This study shows that the mean strength of the improved structure by J.S.P. is 1.9 times greater than by J.S.P.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.23-28
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• 2006

Many services have been served by the exiting subway systems since they have opened in 1975. But its efficiency and competition were going down because of the high construction cost and difficult connection with other transportations, etc. Otherwise, the light rail transit system is much lower construction cost than the subway and the high way building. Also those systems are good at the inexpensive operation cost, the fixed time and safety, the easy access. Recently, the several provinces are planning or advancing the light rail transit system because of these many benefits. Consequently, those system's economical feasibility analysis is required rapidly to show the resonable construction's cause and to get the private investment. This paper offers the system's economical feasibility through the several benefit analysis after the light rail transit system's construction.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.876-883
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• 2012

The paper investigates three types of transfer function methods for detecting displacements of winding in a model transformer. To acquire these transfer functions, the measuring method of input voltage, current and its response is used in impulse method. The applied impulse voltages had three rising times, which were short rising time (less than 0.6 ${\mu}s$), medium rising time (about 0.8 ${\mu}s$) and long rising time (about 1 ${\mu}s$) in front waves. Every 10 measurements of voltage and current waves were averaged from 50 measurements of voltage and current waves. These transfer functions were tested in normal, 24mm elevated and 48mm elevated windings conditions and were analyzed with correlation coefficients and spectrum deviations. In the analysis, the results depend on the types of transfer functions and the rising times of input voltages.

• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.251-255
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• 1991

The flavor and organoleptic properties of Hongju prepared by Kokja and Koji method were tested. There was no great difference of total acid in Hongju with different fermentation methods. The alcohol content of Hongju prepared by Koji method was higher than that of Kokja method and methanol content was very little as about $0.02{\sim}0.03$ mg/ml in all samples. The aldehyde content was $7.5{\sim}32$ mg% and fusel oil was higher in Hongju prepared by Koji method than that of Kokja method. As the result of sensory evaluation, new Hongju, S-N prepared by Kokja method with wheat and rice was to be best quality.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.239-240
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• 2011

본 연구의 목적은 다문화가정 이주여성의 여가관을 분석함으로써 다문화가정 이주여성의 여가에 도움을 주는 시사점을 도출하는데 있다. 이 연구는 다문화가정 이주여성을 연구대상으로 유의표집법(purposive sampling method)을 이용하여 표본을 추출하였다. 표집된 170명 중 응답이 부실한 설문지를 제외하고 최종분석에 사용된 사례수는 137명이었다. 설문지의 타당도는 요인분석, 신뢰도는 신뢰도분석을 통하여 검증되었다. 신뢰도는 Cronbach's ${\alpha}$ 값이 .613이상으로 나타났다. 이 연구는 SPSS18.0을 이용하여 요인분석, 신뢰도분석, 교차분석을 실시하였다. 그 결과는 다음과 같다. 첫째, 다문화가정 이주여성들의 평일 여가시간은 1-­2시간이 가장 많았으며, 구체적으로 연령은 26­-30세, 학력은 고졸, 국적은 중국, 기간은 6.1년 이상에서 유의한 차이가 나타났다. 둘째, 다문화 가정 이주여성들의 주말 여가시간은 1-­2시간, 연령에서는 2­-30세가 가장 많았으며, 유의한 차이가 나타났다. 반면, 학력, 국적, 기간, 월수입은 유의한 차이가 나타나지 않았다. 셋째, 다문화가정 이주여성들의 여가제약은 연령, 학력, 국적, 기간, 월수입에 따라 차이가 있다.