• Title/Summary/Keyword: Theoretical Study

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Theoretical and Finite Element Analysis for Structural Strength of Paperboard-stacked Structure (종이성형구조물의 구조적 강도에 대한 이론분석과 유한요소해석)

  • Park, Jong-Min;Lee, Myung-Hoon
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.5 no.1
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    • pp.13-20
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    • 1999
  • Not only is it important that the physical properties of the paperboards be appropriate for the intended end use, but the proper arrangement of the component in the built-up board is essential for attaining the optimum moment of inertia and the maximum load-carrying ability in a box. It is known to be impossible to estimate the stress distribution and deflection pattern by experiments or theoretical analysis when the corrugated fiberboard get the bending force. This study was tried theoretical and finite element analysis to analyze structural strength characteristics of corrugated fiberboards. If the linerboard and corrugating medium of every corrugated fiberboards is made from the same material, the location of neutral axis comes close to inside liner in order of DMA, DM, DMB, SW and DW, and moment of inertia of area decreases in order of DMA, DMB, DW, DM and SW. With the finite element analysis, deflection of applied loads represented SW, DM, DMA, and TW in the order of their value.

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Experimental and Theoretical Study on Main Noise Sources and Its Radiations of Upwind Wind Turbines (상류형 풍력 터빈의 주요 소음원과 방사소음에 대한 실험적/이론적 고찰)

  • Lee, Gwang-Se;Cheong, Cheol-Ung;Shin, Su-Hyun;Jung, Sung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2010.05a
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    • pp.72-73
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    • 2010
  • In this paper, the main noise sources and its radiated noise levels of upwind horizontal-axis wind turbines are experimentally and theoretically investigated. Theoretical predictions for indentifying the dominant source locations are made by using the empirical noise prediction model of Brooks et al. (1989) for the airfoil self noise. Through the comparison of theoretical results with the experimental results, turbulence-boundary-layer-trailing-edge (TBL-TE) noise is revealed to be the dominant source over all frequency range and separation and stall (S-S) noise is possibly important in the relative lower frequency range compared with TBL-TE noise.

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Theoretical Problems behind Teaching English in Elementary Schools

  • Pak, Yunhwa
    • Korean Journal of English Language and Linguistics
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    • v.1 no.3
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    • pp.437-456
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    • 2001
  • This paper raises a question on the theoretical background behind the English education at the elementary school level. The Critical Period Hypothesis (CPH), supporting the common belief of the earlier the better in foreign language learning, which has promoted the strong trend toward teaching English in Korean elementary schools, is analyzed to determine whether it provides a comprehensible picture to explain age-related factors and whether it is a valid hypothesis which can be applicable in an EFL situation such as Korea. This paper concludes that CPH itself is still considered as an impending hypothesis full of unresolved issues and that the present educational situation of Korean elementary schools is rather far from the environment in which the ideas of CPH could practically apply, and thus it may be desirable to find alternative theoretical backgrounds from which the educational programs can be developed and further expanded.

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Flows in a confined cylindrical container with differential rotating top and bottom disks (속도차를 갖는 두 회전판에 의해 유도되는 원통 내부 유동)

  • Park, Jun-Sang
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.487-490
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    • 2008
  • A theoretical study is made of the flow in a confined cylindrical container with differential rotating top and bottom disks. Two kinds of theoretical solution for the azimuthal velocity were obtained: one is an exact solution of Bessel function type and the other is an approximate solution of exponential function type which comes from WKB approximation. Both theoretical solutions are shown to be self consistent with each other as well as a good agreement with previous studies. Moreover, in a range of relatively low Reynolds number, the obtained solution of Bessel function type shows better result than previous solutions.

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Factors on Decision-Making Participation related to Clinical Experience Difference (임상경력에 따른 간호사의 의사결정 참여 영향요인)

  • 임난영;이여진
    • Journal of Korean Academy of Nursing
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    • v.34 no.2
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    • pp.270-277
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    • 2004
  • Purpose: The purpose of this study was to investigate the relationship between decision-making factors(theoretical knowledge, expertise, empowerment, intuition) and participation in proportion to nurses's clinical experience. Method: Data was collected by quota sampling from July 10, 2001 to August 22, 2001 from 132 clinical nurses who work for 3 General hospitals. Data was analyzed using SPSSWIN 10.0 with crosstab, ANOVA, and stepwise multiple regression. Result: Expertise(F=34.347, p=.000), empowerment(F=29.316, p=.000), and participation(F=3.276, p=.041) were significantly different among 3 clinical experience groups. Clinical experience correlated with expertise(r=.551, p=.000) and empowerment(r=.492, p=.000), and Decision-making participation also correlated with expertise(r=.351, p=.000) and empowerment(r=.265, p=.002). Decision-making participation is effected by theoretical knowledge(under 3.00yr clinical experience), expertise(3.01-5.00yr), and empowerment(above 5.01yr). Conclusion: These findings indicate that factors(theoretical knowledge, expertise, or empowerment) on decision-making participation varies as nurses's clinical experience differs. Therefore, decision-making needs bilateral agreement between staff nurses and nurse managers rather than the responsibility of one.

THEORETICAL AND NUMERICAL STUDY ON SCAVENGE CHARACTERISTICS IN A SUBCHAMBER OP AN HCCI ENGINE (HCCI 엔진 부실내 소기특성에 대한 이론 및 수치해석적 연구)

  • Suh Y.K.;Heo H.S.
    • Journal of computational fluids engineering
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    • v.10 no.2
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    • pp.21-29
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    • 2005
  • In this paper, we present the theoretical and numerical results of scavenge characteristics in a small subchamber of an HCCI(Homogeneous Charge Compression Ignition) engine. Two theoretical models are proposed in prediction of the scavenge time and the efficiency; one is the non-mixing model in which the input gas(CH4) and the existing gas(air) do not mix at all, and the other is the fully-mixed model in which the two gases are assumed to mix completely before ejection. Focus is also given to the effect on the scavenge performance of the size of the chamber outlet.

A Study on the Calculation Formulae of Required Air and Burning Gas Amount of Heavy Fuel Oil (중유의 연소에 필요한 소요공기량과 발생가스량의 산식에 관한 연구)

  • 이우환
    • Journal of Advanced Marine Engineering and Technology
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    • v.6 no.1
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    • pp.34-40
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    • 1982
  • The characteristics of typical 17 kinds of fuel oils are studied to fine the calculation formulae for the required amount of air and the combustion gas amount. 1) The author's calculation formulae are as follows; (1) Theoretically required amount of air (2) Theoretical amount of combustion gas 2) Theoretical amount of the required air in combustion and combustion gas of fuel oils are always estimated less with Rosin's formula than with author's one. 3) Theoretical amount of the required air and the amount of combustion gas of fuel oils are more reasonable with author's formula than Rosin's one in comparison with results of actual analysis.

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Leuconostoc mesenteroides NRRL B-1149를 이용한 Mannitol 생산

  • Kim, Chang-Yong;Jo, Gap-Su;Ryu, Hwa-Ja;Lee, Gwang-Ok;Lee, Jin-Ha;Kim, Do-Won;Kim, Do-Man
    • 한국생물공학회:학술대회논문집
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    • 2002.04a
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    • pp.177-179
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    • 2002
  • The process for the production of mannitol with fructose (5% to 25%) using Leuconostoc mesenteroides NRRL B-1149 was investigated. Optimization study for mannitol production was carried out in 8 liter batch or fed-batch cultures at $28^{\circ}C$, pH 5.0, without aeration. When 5% fructose was used in a batch culture fermentation, the yield of mannitol was 78% of theoretical. As the concentration of fructose was increased to 10% in a batch culture, the yield was reduced to 59.6% of theoretical. Using a fed-batch fermentation with 10% fructose, the yield was increased to 81.9%. When 15% fructose was used for a fed batch fermentation 5% fructose was initially added and the last 10% fructose was supplied continuously. The final yield of mannitol was 83.71% of theoretical. When 20% fructose was used, the yield was more higher, 89.48%.

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Non-convex penalized estimation for the AR process

  • Na, Okyoung;Kwon, Sunghoon
    • Communications for Statistical Applications and Methods
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    • v.25 no.5
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    • pp.453-470
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    • 2018
  • We study how to distinguish the parameters of the sparse autoregressive (AR) process from zero using a non-convex penalized estimation. A class of non-convex penalties are considered that include the smoothly clipped absolute deviation and minimax concave penalties as special examples. We prove that the penalized estimators achieve some standard theoretical properties such as weak and strong oracle properties which have been proved in sparse linear regression framework. The results hold when the maximal order of the AR process increases to infinity and the minimal size of true non-zero parameters decreases toward zero as the sample size increases. Further, we construct a practical method to select tuning parameters using generalized information criterion, of which the minimizer asymptotically recovers the best theoretical non-penalized estimator of the sparse AR process. Simulation studies are given to confirm the theoretical results.

A Furniture Design Process in Residential Spaces (거실과 주침실을 중심으로 한 주거공간 가구 디자인 프로세스)

  • 박영순;신인호;박영선;하승아
    • Journal of the Korea Furniture Society
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    • v.11 no.2
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    • pp.85-94
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    • 2000
  • furniture reflects historical, cultural, spatial background of human life style. This means that we cannot think of a furniture apart from the living environment. This study is focused on the process of furniture design in residential interiors. Furniture design process devided into the theoretical research the formal design process. Basically theoretical background contains human activities in place, antropometric data, requisite furniture type according to activities and some guidelines for design. And the formal design process is consisted of visual main concept, series of sketches and the development of alternatives of design. Thus, the theoretical background need to be applied to the steps of sketches, and for the harmonious interiors systematically.

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