• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.166-167
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• 2016

Unlike the past, supported by the development of digital technologies, free-form buildings are frequently designed with creative thoughts of architectural designers. However, there are some difficulties preventing successfully completion of projects, like reduced productivity and increased construction duration and cost upon the process of producing and installing concrete panels for free-form structures. In particular, there are active studies on the CNC machine for production of free-form concrete panels. Yet, it is difficult to effectively and easily come up with information on production and installation of free-form, curve-surfaced panels which are difficult to be mathematically defined. This requires a lot of manpower and time to implement the curved surfaces of free-form buildings as intended by architects. Accordingly, it needs a model that can effectively create production-installation data of free-form concrete panels for successful free-form building projects. Thus, the purpose of the study is to suggest data estimation model of production-installation using mathematical algorithm in free-form concrete panels. The study results will realize effective production and installation of free-form concrete members, allowing improved productivity of projects, reduced cost and shortened construction duration.

• 한국산학기술학회논문지
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• 제14권10호
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• pp.4855-4864
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• 2013

본 연구의 목적은 숲에서 유아들의 자유놀이가 유아의 사회성 발달에 미치는 영향을 알아보는 것이다. 이 연구를 위해 제주시 H 유치원의 만 4세 유아 24명이 참여하였다. 참여자들은 매회 2시간씩 자신들의 흥미와 요구에 따라 자발적으로 숲에서의 자유놀이를 하였다. 이 자유놀이는 매주 2회씩, 총 12주에 걸쳐 수행되었다. 숲에서의 자유놀이활동의 효과를 검증하기 위해 전후검사 t-검증을 실시하였으며 그 결과는 다음과 같다. 첫째, 숲에서의 자유놀이활동은 유아의 사회성을 향상시켰다. 둘째, 숲에서의 자유놀이활동은 사회성의 하위요인인 협동성, 조망수용능력, 자율성, 그리고 상호작용 모두에 유의한 향상을 가져왔다. 이러한 연구결과를 통해 숲은 유아들 스스로 다양하고 새로운 놀이를 만들 수 있는 풍부한 자연물을 제공하며, 숲에서의 이러한 놀이활동은 유아들 상호간에 활발한 교류를 통해 원만한 친구관계를 형성하게 할뿐만 아니라 유아들의 사회성 발달에 긍정적인 영향을 미친다는 것을 알 수 있다.

• 전자공학회논문지B
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• 제30B권1호
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• pp.10-17
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• 1993

This paper analyzes succinct graph descriptions and its complexity of connectivity problems on context free graph languages under various restrictions. It defines SNLC(Simple Context Free Node Label Controlled) grammar and presents reduction method that solves graph problems without expanding the hierarchical description. It exemplifies the method by giving efficient solutions to connectivity problems on graphs and presents parallel algorithm for reduction and analyzes the complexity. Its results will help application of desing for NETWORK. CAD. VLSI and other engineering problems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.9-23
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• 1993

Free-form surface machining is usually performed with an NC milling machine and a ball end milling cutter. Since this conventional method is basically sculpting on a plane, it is not suitable for three dimensional body machining. This article will introduce a new machining method for three dimensional body with free-form surface and newly developed machine tool suitable for such machining.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.237-240
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• 2000

It is expected that there will be the regulation for limiting the amount of Hg content in cold cathode fluorescent lamp (CCFL) for LCD backlight system. Now it is necessary to develop mercury-free backlight system. The mercury-free CCFL coated with PDP phosphors was fabricated and evaluated. The CCFL filled with Xe and Ne showed 4500 ㏅/$m^2$ with efficiency of 13 lm/W.

• International Journal of Fluid Machinery and Systems
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• 제7권2호
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• pp.68-79
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• 2014

The type of turbine developed is based on the very low head of water potential source for the electric power production. The area of research is focused for the axial water turbine that can be applied at the simple site open channel with has a very low cost and environmental impact compared to the conventional hydro installation. High efficiency of axial turbine which applied to the very low potential head will made this type of turbine can be used at wider potential site. Existing irrigation weir and river area will be the perfect site for this turbine. This paper will compare the effects of the variation of swirl velocity criterion during the design of the blade of guide vane and rotor of the turbine. Effects of the swirl velocity criterion is wider known as a vortex conditions (free vortex, force vortex and swirl velocity constant), and the free vortex is the very popular condition that applied by most of turbine designer, therefore will be interesting to do a comparison against other criterion. ANSYS Fluent will be used for simulation and to determine the predictive performance obtained by each of design criteria.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제26권2호
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• pp.108-120
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• 2022

We considered qualitative behaviour of the generalization of Einstein's model of Brownian motion when the key parameter of the time interval of free jump degenerates. Fluids will be characterised by number of particles per unit volume (density of fluid) at point of observation. Degeneration of the phenomenon manifests in two scenarios: a) flow of the fluid, which is highly dispersing like a non-dense gas and b) flow of fluid far away from the source of flow, when the velocity of the flow is incomparably smaller than the gradient of the density. First, we will show that both types of flows can be modeled using the Einstein paradigm. We will investigate the question: What features will particle flow exhibit if the time interval of the free jump is inverse proportional to the density and its gradient ? We will show that in this scenario, the flow exhibits localization property, namely: if at some moment of time t₀ in the region, the gradient of the density or density itself is equal to zero, then for some T during time interval [t₀, t₀ + T] there is no flow in the region. This directly links to Barenblatt's finite speed of propagation property for the degenerate equation. The method of the proof is very different from Barenblatt's method and based on the application of Ladyzhenskaya - De Giorgi iterative scheme and Vespri - Tedeev technique. From PDE point of view it assumed that solution exists in appropriate Sobolev type of space.

• 한국지구과학회지
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• 제38권6호
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• pp.427-441
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• 2017

Theory of Earth's free oscillation is revisited. Firstly, we summarized the underlying formulations, such as the equation of motion and its conversion into numerically integrable form and then explained computational procedures including the treatment of inner core-outer core boundary and core-mantle boundary, while the latter information has not been explicitly given in most publications. Secondly, we re-calculated the periods of Earth's free oscillation modes (period >200 s) for PREM model. In doing so we acquired the values of modes missing in Dziewonski and Anderson (1981). As a case observation, one seismogram after 2011 Tohoku earthquake recorded at Daejeon, Korea (KIGAM seismic station) was briefly analyzed to identify free oscillation mode excitations on its spectra. The material in this article will be most clear guide for those on calculating the Earth's free oscillation mode.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.27-30
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• 1997

1. Introduction : Molecular diffusion of small molecules in polymers plays an important role in many areas where polymers are acting as barriers, and in separation processes, such as selective diffusion. Different applications of polymers have different requirements on their transport properties. Therefore, reliable predictions of diffusion coefficients for small molecules in polymeric materials could be a useful tool to design appropriate materials. For many years, the theories based on free-volume concepts have been widely used to correlate and predict diffusion behavior in polymer/solvent systems. In the theory derived by Vrentas and Duda, the empty space between molecules that is available for molecular transport, referred to as hole free-volume, is being redistributed. Molecular transport will occur only when a free-volume of sufficient size appears adjacent to a molecule and the molecule has enough energy to jump into this void. The diffusive jump is considered complete when the void left behind is closed before the molecule returns to its original position. In this paper, the Vrentas-Duda free-volume theory is presented and the methods to estimate free-volume parameters for predicting polymer/ solvent diffusion coefficients are described in detail.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.53-54
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• 2019

Currently, the market for free-form building continues to grow, but the technology for construction of free-form building in Korea is still in need of much study. In this study, we focused on this problem and conducted basic study for development a side formwork control system to product various types of FCP. As a result of this study, it is expected that it will be able to secure competitiveness for the free-form building market, which is expected to contribute greatly to the growth of the construction industry.