• Advances in aircraft and spacecraft science
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• 제7권1호
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• pp.19-40
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• 2020

In the present study, a fifth-order shear and normal deformation theory using a polynomial function in the displacement field is developed and employed for the static analysis of laminated composite and sandwich simply supported spherical shells subjected to sinusoidal load. The significant feature of the present theory is that it considers the effect of transverse normal strain in the displacement field which is eliminated in classical, first-order and many higher-order shell theories, while predicting the bending behavior of the shell. The present theory satisfies the zero transverse shear stress conditions at the top and bottom surfaces of the shell. The governing equations and boundary conditions are derived using the principle of virtual work. To solve the governing equations, the Navier solution procedure is employed. The obtained results are compared with Reddy's and Mindlin's theory for the validation of the present theory.

• ETRI Journal
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• 제10권4호
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• pp.146-160
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• 1988

The purpose of the present study is to build a model to determine the structure of long-term quasi-optimal rates of local and toll telephone services. The outline of this study is as follows : Telephone business, providing social goods, is capital-intensive industry which needs huge fixed cost to operate exchanges and telephone networks nationwide. The nature of above industry justifies the market structure of telephone business to be natural monopoly and makes a good reason for government's direct regulation, that is, price regulation. Three is a gap between the present rates and the quasi-optimal ones because some administrative processes intervene in rate making process before execution. On the above diagnostic basis, the present study made an empirical test for the optimality of present rates structure in connection with Ramsey-Boiteux model to maximize the sum of producer's and consumer's surplus and also the current study proposed a qusasi-optimal rates structure for better market performance. From the empirical analysis, we can deduce a policy recommendation the local price should be increased to 47% whereas toll price decreased to 24% in order to improve the net welfare worth of 32.6 billion won.

• 대한수학회지
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• 제46권5호
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• pp.1087-1103
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• 2009

Given a system of s independent 1-forms on a smooth manifold M of dimension m, we study the existence of integral manifolds by means of various generalized versions of the Frobenius theorem. In particular, we present necessary and sufficient conditions for there to exist s'-parameter (s' < s) family of integral manifolds of dimension p := m-s, and a necessary and sufficient condition for there to exist integral manifolds of dimension p', p' $\leq$ p. We also present examples and applications to complex analysis in several variables.

• 한국안광학회지
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• 제9권1호
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• pp.43-51
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• 2004

안경원은 직접 소비자와 접촉하는 소매업으로써 안경원의 경영방침, 개선 및 발전 방향을 연구하고자 한다. 이러한 목적으로 안경원의 현재 상태와 문제점 조사하였다. 이에 따른 안경원의 현황과 경영관리상의 문제점을 제시하고 그 문제점의 개선방향을 제안하여 안경원 경영에 유용한 경영방법을 제시하고자 한다.

• 아동학회지
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• 제20권2호
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• pp.75-89
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• 1999

Children's textbooks and women's manuals were used to investigate parent-child relationships under the Neo-Confucianism of the Chosun Dynasty compared with the present. Current practices of filial piety (Hyo) have changed but are still based on Neo-Confucianism. In present-day child rearing, parents aim to love their children (Ja-Ae) and to teach them Neo-Confucian values.

• 한국가정과교육학회지
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• 제27권4호
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• pp.155-172
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• 2015

본 연구는 어머니의 개인적 관계적 속성과 현 자녀속성이 후속출산계획에 미치는 영향과 어머니의 취업여부에 따라 후속출산계획을 예측하는 요인을 알아보기 위해 수행되었다. 본 연구대상은 한국아동패널조사에 참여한 어머니 1,635명이었으며, 조사도구는 어머니의 월평균 가구소득, 양육스트레스, 자녀가치, 결혼만족도, 사회적 지원, 기존 자녀의 출생순위와 성별을 측정하기 위한 자기기입식 설문지이었다. 수집된 자료는 SPSS 22.0 프로그램을 사용하여 기술통계와 t 검증 및 ${\chi}^2$ 검증, 의사결정나무분석을 통해 분석되었다. 본 연구의 주요결과는 다음과 같다. 첫째, 어머니의 양육스트레스, 자녀가치, 결혼만족도, 사회적 지원, 자녀의 출생순위와 성별은 후속 출산계획에 영향을 미친 반면 월평균 가구소득은 영향을 미치지 않는 것으로 나타났다. 둘째, 비취업모의 경우 자녀의 출생순위와 성별, 자녀가치가 후속출산계획을 예측하는 주요인으로 제시되었는데, 현 자녀가 첫째이면서 여아일 경우 후속출산계획을 수립할 가능성이 가장 높았으며, 자녀가 첫째이면서 남아일 경우 자녀에 가치를 부여하는 정도가 높을수록 후속출산계획을 수립하는 것으로 나타났다. 취업모의 경우 자녀의 출생순위와 결혼만족도가 후속출산계획을 가장 잘 예측하는 요인으로 나타났으며, 현 자녀가 첫째이면서 결혼만족도가 높을 경우 후속출산계획을 수립할 가능성이 높았다. 마지막으로, 후속출산율 제고방안으로, 인구교육의 필요성과 가정교과의 역할을 제안하였다.

• 한국산학기술학회논문지
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• 제3권3호
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• pp.170-176
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• 2002

The purpose of the present study is to find design factors that have an effect on man's foot, and to develop an optimal last for man's functional shoe design based on these factors. Analyzing 4000 men's foot data, three men were selected for fitting test with the last and shoes manufactured in the present work. Based on the results of the fitting test, the modifications of last for the optimal design have been made using CAD/CAM technologies.

• 호남수학학술지
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• 제45권1호
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• pp.160-183
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• 2023

In the present paper, we prove that our main inequality reduces to some trapezoid and Newton type inequalities for differentiable s-convex functions. These inequalities are established by using the well-known Riemann-Liouville fractional integrals. With the help of special cases of our main results, we also present some new and previously obtained trapezoid and Newton type inequalities.

• Kyungpook Mathematical Journal
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• 제60권2호
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• pp.255-277
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• 2020

Divide knots and links, defined by A'Campo in the singularity theory of complex curves, is a method to present knots or links by real plane curves. The present paper is a sequel of the author's previous result that every knot in the major subfamilies of Berge's lens space surgery (i.e., knots yielding a lens space by Dehn surgery) is presented by an L-shaped curve as a divide knot. In the present paper, L-shaped curves are generalized and it is shown that every knot in the minor subfamilies, called sporadic examples of Berge's lens space surgery, is presented by a generalized L-shaped curve as a divide knot. A formula on the surgery coefficients and the presentation is also considered.

• 디자인학연구
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• 제16권4호
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• pp.365-374
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• 2003

The purpose of the present study was to improve the artistic qualities in the future fashion design by investigating how the art to wear was applied to the inspiration in the modern fashion design in the late 1990s. For this purpose the present paper examined characteristics in art to wear and their impact on modern fashion design in the late 1990s. Distinguished from the traditional costume, art to wear disregarded a fixed concept on design elements such as the socio-cultural images, materials, and forms. The artists in art to wear freely expressed their "selves" and their individuality to their works in a variety of ways. In fashion design in the late 1990s the creative characteristics of art to wear were reflected in four ways: (1) eco-look, (2) humor, (3) deformation, (4) materials. The present study suggests that the creativity of the art to wear can establish the potentials and possibility in modern fashion design, and art to wear can be a crucial mediator in opening art into the real world.