• 대한가정학회지
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• 제40권12호
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• pp.1-11
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• 2002

This paper is intended as an analysis of the Chapter on Family in textbooks of a Middle school course at the aspect of Parson's Structural Functionalism Theory. In this analysis, We'd like to explore how the value of family is expressed in the Art-Home Economics textbooks. Generally, family is a subsystem in the structural system of whole society and family has two main functions to promote stability and equilibrium from the Parson's Structural Functionalism Theory point of view. Today, the concern with the Structural Functionalism Theory is dominantly reflected in textbooks, even though it has been proposed that the Structural Functionalism is not appropriate to explain family of modem society. Like that, the question now arises: the family history and interaction is ignored in the Structural Functionalism Theory. That is to say, There are limitations of Structural Functionalism Theory. The textbooks of Art-Home Economics was based on the revised curriculum has been severely changed in terms of external system of textbooks. But, we didn't know how much the view of the Structural Functionalism Theory is involved in textbooks. In this article, we analyze the view of the Structural Functionalism Theory in the Art- Home Economics textbooks using the Contents Analysis. At the same time, we find the confusion of family value revealed in textbooks.

• Industrial Engineering and Management Systems
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• 제15권4호
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• pp.385-395
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• 2016

Game theory is a powerful tool for analyzing the Supply chain (SC) with different conflicting elements. Among them, the Stackelberg game is the one in which a player as leader has more power than the other ones as followers. Since in many SC systems one element has, in essence, more power than the others; the Stackelberg game has found many applications in SC studies. In this paper, we apply the Stackelberg game-theoretic approach and the corresponding equilibrium point to formulate and analyze a two echelon VMI SC. Comprehensive computational results on an experimental case are conducted to numerically analyze the performance of VMI system against three groups of critical parameters. Moreover, a critical comparison demonstrates the poorer performance of decentralized VMI system than centralized one. This naturally necessitates designing proper contracts between VMI partners in order to more effectively implement the realistic decentralized system.

• 대한기계학회논문집A
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• 제20권8호
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• pp.2449-2457
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• 1996

This paper presents a design method for autopilot control system in course change to the specified direction based on a robust digital servo controlmelthod incorporating the concept of the annihilator polynormial. The mathematicalmodel of ship turning motion is very complex in the view of practical control because it has time varying parameters, nonlinear and dead time terms. To apply the digital servo control method based on computer control, the model is linearized at an equilibrium point and discretized with appropriate sampling time. The control algorithm was evaluated on the basis of computer simulation for a model ship and the practical experiment was carried out with an image processing method for measurement of ship position in a water tank. The results of overall experiments show that the proposed control method will be one of good way to keep a track plotted in the map.

• 물과 미래
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• 제11권1호
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• pp.39-46
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• 1978

The approaching deep water wave heights and directions affect the wave energy which is carried to the coast. By studing the relations between the longshore wave energy theory and the evolution of coastline, writer can arrive following conclusion. The longshore lottoral drifting affects to a great deal the formation of the coast, and by investigating on the eastern coastal geomophorogy of korea, the theory was proued as a true and made it possible to an approaching to the subdivided classification of eastern coast of lorea. That is to asy that angle taken by the level between the wave crest line of prevailing wave(NE) and the coastline was measured as less than 15#, and in the area neighboring the river which served as source of Sand parrticles, there are grand scale formation of sand beach expectable, in the other hand the formation of sand beach in case of $35^{\circ}{\leq}{\alpha }o{\leq}55^{\circ}$ which represents the vivid phenomena of longshore littoral drifting was proved not influencial but rather transformed into a rocky coast. Depending on the above facts the writer classified general shape of the coast affected by the vivid wave action into the following three, (1) The equilibrium beach. (2) Erosinal beach. (3) Geomophorogical beach, and made the sandy and rocky coast are subdivided as S-A.B.C. and R-DEF.

• 한국유체기계학회 논문집
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• 제7권5호
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• pp.20-28
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• 2004

Static and dynamic structural analyses of a turbine bladed-disk for a liquid rocket turbopump are performed to investigate the safety level of strength and vibration at design point. During operation, turbopump is exposed to various external loads. Therefore, the effects of them should be carefully considered and properly modeled. First, due to the high rotational speed of the turbopump, effects of centrifugal forces are considered in the structural analysis. Thermal load caused by severe temperature differences is also considered. A three dimensional finite element method (FEM) is used for linear and nonlinear structural analyses with modified Newton-Raphson iteration method. After the nonlinear solution is obtained from the structural analysis, dynamic characteristics are obtained as a function of rotational speed from the linearized eigenvalue analysis at an equilibrium position. From the analysis results, characteristics of stress distribution and vibration were thoroughly examined and investigated.

• Structural Engineering and Mechanics
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• 제30권4호
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• pp.403-426
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• 2008

Externally bonding fiber reinforced polymer (FRP) sheets with an epoxy resin is an effective technique for strengthening and repairing reinforced concrete (RC) beams under flexural loads. Their resistance to electro-chemical corrosion, high strength-to-weight ratio, larger creep strain, fatigue resistance, and nonmagnetic and nonmetallic properties make carbon fiber reinforced polymer (CFRP) composites a viable alternative to bonding of steel plates in repair and rehabilitation of RC structures. The objective of this investigation is to study the effectiveness of CFRP sheets on ductility and flexural strength of reinforced high strength concrete (HSC) beams. This objective is achieved by conducting the following tasks: (1) flexural four-point testing of reinforced HSC beams strengthened with different amounts of cross-ply of CFRP sheets with different amount of tensile reinforcement up to failure; (2) calculating the effect of different layouts of CFRP sheets on the flexural strength; (3) Evaluating the failure modes; (4) developing an analytical procedure based on compatibility of deformations and equilibrium of forces to calculate the flexural strength of reinforced HSC beams strengthened with CFRP composites; and (5) comparing the analytical calculations with experimental results.

• 전기학회논문지
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• 제60권2호
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• pp.407-415
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• 2011

In this study, we propose the design of optimized fuzzy controller for the rotary inverted pendulum system by using differential evolution algorithm. The structure of the differential evolution algorithm has a simple structure and its convergence to optimal values is superb in comparison to other optimization algorithms. Also the differential evolution algorithm is easier to use because it have simpler mathematical operators and have much less computational time when compared with other optimization algorithms. The rotary inverted pendulum system is nonlinear and has a unstable motion. The objective is to control the position of the rotating arm and to make the pendulum to maintain the unstable equilibrium point at vertical position. The output performance of the proposed fuzzy controller is considered from the viewpoint of performance criteria such as overshoot, steady-state error, and settling time through simulation and practical experiment. From the result of both simulation and practical experiment, we evaluate and analyze the performance of the proposed optimal fuzzy controller from the comparison between PGAs and differential evolution algorithms. Also we show the superiority of the output performance as well as the characteristic of differential evolution algorithm.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1163-1170
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• 2014

Due to global environmental regulations and policies with rapid advancement of renewable energy technologies, the development type of renewable energy sources (RES) in power systems is expanding from small-scale distributed generation to large-scale grid-connected systems. In the near future, it is expected that RES achieves grid parity which means the equilibrium point where the power cost of RES is equal to the power costs of conventional generators. However, although RES would achieve the grid parity, the cost related with development of large-scale RES is still a big burden. Furthermore, it is hard to determine a suitable capacity of RES because of their output characteristics affected by locations and weather effects. Therefore, to determine an optimal capacity for RES becomes an important decision-making problem. This study proposes a method for determining an optimal installed capacity of RES from the business viewpoint of an independent power plant (IPP). In order to verify the proposed method, we have performed case studies on real power system in Incheon and Shiheung areas, South Korea.

• Journal of Power Electronics
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• 제13권6호
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• pp.1008-1015
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• 2013

By using fractional calculus and the circuit-averaging technique, the modeling and analysis of a Buck converter with fractional order inductor and fractional order capacitor in discontinuous conduction mode (DCM) operations is investigated in this study. The equivalent averaged circuit model of the fractional order Buck converter in DCM operations is established. DC analysis is conducted by using the derived DC equivalent circuit model. The transfer functions from the input voltage to the output voltage, the duty cycle to the output voltage, the input impedance, and the output impedance of the fractional order Buck converter in DCM operations are derived from the corresponding AC-equivalent circuit model. Results show that the DC equilibrium point, voltage ratio, and all derived transfer functions of the fractional order Buck converter in DCM operations are affected by the inductor order and/or capacitor order. The fractional order inductor and fractional order capacitor are designed, and PSIM simulations are performed to confirm the correctness of the derivations and theoretical analysis.

• 한국강구조학회 논문집
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• 제23권2호
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• pp.237-247
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• 2011

현수교의 초기평형상태를 결정하기 위한 개선된 초기부재력법을 제시한다. 먼저 현수교의 주케이블과 행어가 만나는 절점에서 힘의 평형조건을 이용하여 초기평형상태를 결정한 뒤, 이 때 계산된 주 케이블의 절점좌표와 각 케이블 부재의 무응력장을 입력 값으로 하여 초기부재력을 도입한 비선형 해석을 수행하였다. 일반적인 초기부재력법의 경우 각 단계에서 계산된 부재력을 통하여 케이블의 무응력장을 재산정하지만, 본 연구에서는 각 케이블 부재의 무응력장을 매 계산 단계에서 고정된 값으로 취한다. 2차원 및 3차원 현수교 모델에 공통적으로 적용할 수 있다. 수치예제 결과 값의 비교를 통하여 연구의 타당성을 검증하였다.