• Title/Summary/Keyword: simplified method

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A Study on the Simplified Presumption Method for the Prediction of Cooling and Heating Performance in a Fresh Air Load Reduction System by Using Geothermal Energy (지열 이용 외기부하 저감시스템의 냉각 및 가열효과 예측 간이추정법에 관한 연구)

  • Son, Won-Tug;Choi, Young-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.13 no.3
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    • pp.169-181
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    • 2010
  • This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we proposed a simplified presumption method for the prediction of cooling and heating performance in the system. In conclusion the proposed method has been verified by comparing with the calculated value of the numerical analysis model by using nonlinear two-dimension hygroscopic question.

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Saponin Analysis and Red Ginseng Production using the Simplified Method of Korean Ginseng (Panax ginseng C.A.Meyer) (고려인삼(Panax ginseng C.A.Meyer)의 간이법에 의한 홍삼제조 및 사포닌 성분분석)

  • In Jun-Gyo;Kim Eun-Jeong;Lee Bum-Soo;Park Myung-Han;Yang Deok-Chun
    • Korean Journal of Plant Resources
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    • v.19 no.1
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    • pp.133-138
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    • 2006
  • In order to enhance the components of bioactive ginsenosides and the manufacturing process of red ginseng, we developed the simplified method for red ginseng production. The red ginseng extract was prepared from red ginseng produced with the simplified method, and the production rate of extract ($62^{\circ}$ brix) was more than 60%. The ginsenosides of red ginseng were purified and analyzed by HPLC using ELSD. Ginsenoside-$Rg_3,\;Rh_2$ and $Rh_1$, specific artifacts found only in red ginseng, were detected by HPLC. Especially, contents of ginsenoside-$Rg_3$ and Rh1 were detected high than two times in red ginseng produced the simplified method compared to commercial products.

Simplified P-M interaction curve model for reinforced concrete columns exposed to standard fire

  • Lee, Deuck Hang;Cheon, Na-Rae;Kim, Minsu;Lee, Jungmin;Oh, Jae-Yuel;Kim, Kang Su
    • Computers and Concrete
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    • v.19 no.5
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    • pp.545-553
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    • 2017
  • In the authors' previous study, an axial force-flexural moment (P-M) interaction curve model was proposed to evaluate fire-resisting performances of reinforced concrete (RC) column members. The proposed method appeared to properly consider the axial and flexural strength degradations including the secondary moment effects in RC columns due to fire damage. However, the detailed P-M interaction curve model proposed in the authors' previous study requires somewhat complex computational procedures and iterative calculations, which makes it difficult to be used for practical design in its current form. Thus, the aim of this study was to develop a simplified P-M interaction curve model of RC columns exposed to fire considering the effects of fire damage on the material performances and magnitudes of secondary moments. The simplified P-M interaction model proposed in this study was verified using 66 column fire test results collected from literature, and the verification results showed that the proposed simplified method can provide an adequate analysis accuracy of the failure loads and fire-resisting times of the RC column specimens.

Simplified Estimation Method for Collective Uncertainty-Propagations of Hysteretic Energy Dissipating Device's Properties

  • Shin, Dong-Hyeon;Kim, Hyung-Joon
    • International journal of steel structures
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    • v.18 no.5
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    • pp.1508-1524
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    • 2018
  • Hysteretic energy dissipating devices (HEDDs) have been increasingly applied to building construction to improve the seismic performance. The seismic responses of such damped structures are significantly affected by HEDD's structural properties. An accurate investigation on the propagation of HEDD's structural properties is required for reasonable evaluation of the seismic performance of a structure. This study aims to develop simplified methods that can estimate the collective uncertainty-propagation to the seismic response of damped structures employing HEDDs. To achieve this, three- and six-story steel moment-resisting frames were selected and the propagations of the individual HEDD's property-uncertainties were evaluated when they are subjected to various levels of seismic demand. Based on the result of individual uncertainty-propagations, a simplified method is proposed to evaluate the variation of seismic response collectively propagated by HEDD's property-uncertainties and is verified by comparing with the exact collective uncertainty-propagation calculated using the Monte Carlo simulation method. The proposed method, called as a modified SRSS method in this study, is established from a conventional square root of the sum of the squares (SRSS) method with the relative contributions of the individual HEDD's property-uncertainty propagations. This study shows that the modified SRSS method provides a better estimation than the conventional SRSS method and can significantly reduce computational time with reasonable accuracy compared with the Monte Carlo simulation method.

A Suggestion of Simplified Load Formula for Blast Analysis (폭발해석을 위한 간략 폭발하중 제안식)

  • Jeon, Doo-Jin;Han, Sang-Eul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.1
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    • pp.67-75
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    • 2016
  • In this paper, a pressure-time history curve of blast load and Conwep model are presented, and a simplified blast load formula is suggested. Generally, a blast load are applied as a pressure-time history curve, and it is calculated by blast load formula such as Conwep model. The Conwep model which is used in most of the blast analysis is quiet difficult to calculate because of its complex process. Therefore, a simplified formula is proposed to calculate blast load by simple rational expressions and to make a simplified pressure-time history curve. In this process, a curve fitting method was used to find the simple rational expressions. The calculation results of the simplified formula have an error of less than 1% in comparison with the Conwep model. And, blast analyses using finite elements method are accomplished with the Conwep model and simplified formula for verification.

An Analysis on a Torque Error of a 3-Phase Induction Motor due to Simplified Equivalent Circuit (3상 유도전동기의 간이등가회로에 의한 토크 오차 분석)

  • Shin, Myoung-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.1
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    • pp.45-49
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    • 2014
  • Torque of an induction motor is generally calculated by simplified equivalent circuit. However, the torque has an error since it is calculated by simplified equivalent circuit. In this paper, stator and rotor currents, torque, efficiency, and power factor are derived from the equivalent circuit of an induction motor using mesh analysis method. Then, they are compared with those calculated from simplified equivalent circuit.

Comparison of the Numerical Methods for the Optimum Antireflection Coatings of Laser Diode Facets (레이저 다이오드 단면의 최적 무반사 코팅을 위한 수치해석 방법 비교)

  • 이세진;김부균
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.12
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    • pp.1935-1944
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    • 1993
  • We calculate the optimum refractive index and thickness for a single layer antireflection coating as a function of active layer thickness of a laser diode using three different simplified numerical methods. The difference of the results using three methods comes from that of the effective refractive index of a laser used in three methods. We compare three simplified methods to an exact method to check the validity of the simplified methods. We conclude that the simplified method, choosing the effective index of a laser diode as a function of incidence angle of each plane wave composing of a guided mode agree well to an exact method for both TE and TM modes and the cases of strongly and weakly guiding.

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On a Simplified Measurement of Rail Irregularity by Axle-box Accelerometers (축상 진동가속도계를 이용한 궤도불규칙의 간이검측에 관한 연구)

  • Lee, Jun-Seok;Choi, Sung-Hoon;Kim, Sang-Soo;Park, Choon-Soo
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.989-995
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    • 2010
  • This paper is focused on a simplified measurement of rail irregularity by some axle-box accelerometers for high-speed rail condition monitoring with in-service high-speed trains. Generally, the rail condition monitoring has been done by a special railway inspection vehicle with a 10m versine method. But, the monitoring method needs some expensive measurement system, and have been performed only at night due to its speed limit. In this research, a simplified measurement of rail irregularity using axle-box accelerometers is proposed to monitor the rail condition with in-service high-speed trains. The acceleration is measured by using two accelerometers on a axle-box, and stored in an on-board data acquisition system. The displacement is estimated from the acceleration data by a combination of Kalman filter and the frequency selective filter. The estimated results are compared with the measurement from a laser rail inspection system which is near the axle-box. From the comparison, the proposed method shows promise as a tool for the simplified measurement of rail irregularity at high-speed.

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A Simplified Method for Creep Analysis of R/C Beams (철근콘크리트 보의 크리이프 단순 해석법)

  • 곽효경;서영재
    • Computational Structural Engineering
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    • v.10 no.4
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    • pp.267-280
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    • 1997
  • This paper deals with the development of simplified methods to predict the creep deformation of reinforced concrete beams. The layer approach based on a degenerate kernel of compliance function in form of Dirichlet series is mentioned and a simplified analytical method derived from the equilibrium equations and compatibility conditions is proposed to overcome the sophisticated calculation procedures in the classical creep analysis. Correlation studies between analytical and experimental results and design codes are conducted with the objective to establish the validity of the proposed methods. Besides, various parameter studies are conducted with the objective to identify the effects of cracking, steel ratio and sectional shape in the creep deformation and the obtained results are discussed.

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Simplified Analysis of Rectangular Liquid Storage Tanks Considering Fluid-Structure Interaction (유체-구조물 상호작용을 고려한 직사각형 액체저장탱크의 단순해석법)

  • Lee, Jin Ho;Cho, Jeong-Rae
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.5
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    • pp.203-209
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    • 2022
  • A simplified method for earthquake response analysis of a rectangular liquid storage tank is proposed with fluid-structure interaction considered. In order to simplify the complex three-dimensional structural behavior of a rectangular liquid storage tank, it is assumed that structural deformation does not occur in the plane parallel to the direction in which the earthquake ground motion is applied but in the plane perpendicular to the direction. The structural deformation is approximated by combining the natural modes of the simple beam and the cantilever beam. The hydrodynamic pressure, the structure's mass and stiffness, and the hydrodynamic pressure's added mass are derived by applying the Rayleigh-Ritz method. The natural frequency, structural deformation, pressure, effective mode mass, and effective mode height of the rectangular liquid storage tank are obtained. The structural displacement, hydrodynamic pressure, base shear, and overturning moment are calculated. The seismic response analysis of an example rectangular liquid storage tank is performed using the proposed simplified approach, and its accuracy is verified by comparing the results with the reference solution by the finite element method. Existing seismic design codes based on the hydrodynamic pressure in rigid liquid storage tanks are observed to produce results with significant errors that cannot be ignored.