• Title/Summary/Keyword: Influence coefficient

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Free Vibration Analysis of Double Cylindrical Shells Using Transfer of Influence Coefficent (영향계수의 전달에 의한 2중 원통형 셸의 자유진동해석)

  • Choi, Myung-Soo;Yeo, Dong-Jun
    • Journal of Power System Engineering
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    • v.21 no.5
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    • pp.48-54
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    • 2017
  • The transfer influence coefficient method which is an vibration analysis algorithm based on the transfer of influence coefficient is applied to the free vibration analysis of double cylindrical shells. After the computational programs for the free vibration analysis of double cylindrical shells were made using the transfer influence coefficient method and the transfer matrix method, we compared the results using the transfer influence coefficient method with those by the transfer matrix method. The transfer influence coefficient method provided the good computational results in the free vibration analysis of double cylindrical shells. In particular, The results of the transfer influence coefficient method are superior to those of the transfer matrix method when the stiffness of internal springs connecting a inside cylindrical shell and a outside cylindrical shell is very large.

Free Vibration Analysis of Timoshenko Arcs with Elastic Supports Using Transfer of Influence Coefficient (영향계수의 전달을 이용한 탄성 지지된 티모센코 호의 자유진동 해석)

  • Choi, Myung-Soo;Yeo, Dong-Jun
    • Journal of Power System Engineering
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    • v.21 no.2
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    • pp.70-76
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    • 2017
  • When Timoshenko arcs considering the shear deformation and rotatory inertia have elastic supports, the authors analyze in-plane free vibration of them by the transfer influence coefficient method. This method finds the natural frequencies of them using the transfer of influence coefficient after obtaining the transfer matrix of arc element from numerical integration of the differential equations governing the vibration of arc. In this study, two computer programs were made by the transfer influence coefficient method and the transfer matrix method for analyzing free vibration of Timoshenko arcs. From numerical results of four computational models, we confirmed that the transfer influence coefficient method is a reliable method when analyzing the free vibration of Timoshenko arcs. In particular, the transfer influence coefficient method is a effective method when analyzing the free vibration of arcs with rigid supports.

Influence Function on the Coefficient of Variation (변이계수에 대한 영향함수)

  • Lee, Yun-Hee;Kim, Hong-Gie
    • Communications for Statistical Applications and Methods
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    • v.15 no.4
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    • pp.509-516
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    • 2008
  • We derive the influence function on the coefficient of variation. Empirical influence function and Sample influence function are used to verify the validity of the derived influence function. To show the validity of the influence function, we carry out simulations with random samples from normal distribution $N(20,1^2)$ and $N(20,5^2)$, respectively. The simulation result proves that the derived influence function is very accurate in estimating changes in the coefficient of variation when an observation is deleted.

Enhanced Influence Coefficient Matrix for Estimation of Local Ice Load on the IBRV ARAON (쇄빙연구선 ARAON호의 국부 빙하중 추정을 위한 영향계수행렬의 보완)

  • Cho, Sungrok;Choi, Kyungsik;Son, Beomsik;Jeong, Seong-Yeob;Ha, Jung-Seok
    • Journal of the Society of Naval Architects of Korea
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    • v.58 no.5
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    • pp.330-338
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    • 2021
  • This paper focuses on the improvement of the influence coefficient matrix method for estimation of local ice load on the icebreaking research vessel ARAON. The influence coefficient matrix relates ice pressure on the hull plate to the measured/calculated hull strain/stress. Conventionally von Mises equivalent stresses representing hull stresses and ice pressure acting on the hull plate are utilized to assemble the influence coefficient matrix. Because of the three dimensional features of the ship-ice collision process, an enhanced method to assemble the influence coefficient matrix is derived considering ice loads in the X, Y, and Z direction simultaneously. Furthermore the location of ice loads acting on hull-plate may fall outside the measuring sensor area, and the enhanced influence coefficient matrix is modified to reduce the difference between the actual and the estimated ice loads by expanding the domain outward from the sensor area. The developed method for enhanced influence coefficient matrix is applied to IBRV ARAON during the 2019 Antarctic ice field test and the local ice loads in three directions are efficiently calculated compared to those by a conventional method.

중국 석탄산업의 경제적 효과 분석

  • Choe, Jeong-Seok
    • 중국학논총
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    • no.71
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    • pp.151-167
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    • 2021
  • Looking at the economic effects of the Chinese coal industry analyzed in this text, the following results could be drawn. First, according to the analysis result of the influence coefficient of the Chinese coal industry in 2017, it is mainly rural and regional development It was analyzed that it had a great influence on the necessary sectors. Second, the sensitivity coefficient of the Chinese coal industry in 2017 was presented in the order of electricity and heat production and supply, monetary finance and other financial services, business services, refined petroleum and nuclear fuel processing products, wholesale business, and retail business. It is judged that this is more influenced by government policy than by influence coefficient.

River Embankment Integrity Evaluation using Numerical Analysis (수치해석을 이용한 하천제방의 건전도 평가)

  • Byun, Yo-Seph;Jung, Hyuk-Sang;Kim, Jin-Man;Choi, Bong-Hyuck;Kim, Kyung-Min;Chun, Byung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.524-528
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    • 2009
  • An influence factors for soundness evaluation of river levee include resistibility and embankment for piping of ground consisting embankment in case piping, permeability coefficient of ground, height of embankment, the width of crest, material characteristics of embankment and foundation ground, shape of embankment slope, an influence for penetration of rainfall or river water in case slope stability. In this study, it was operated a feasibility investigation of existing design result, stability evaluation for permeability coefficient use and permeability coefficient change of foundation ground to investigate an influence in line with permeability coefficient change for result of river levee penetration analysis. The evaluation results of influence factors, the permeability coefficient used in design and it was evaluated influence in safety factor of piping. After the evaluation of influence factors, the permeability coefficient used in the design appears with the fact that differs in a design report about same soil, Accordingly, the stability investigation of embankment by application of literature data can affect stability evaluation results by change factors like a permeability coefficient, void ratio. It should be certainly used material properties by a test in soundness evaluation of river levee.

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Research on heat transfer coefficient of supercritical water based on factorial and correspondence analysis

  • Xiang, Feng;Tao, Zhou;Jialei, Zhang;Boya, Zhang;Dongliang, Ma
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1409-1416
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    • 2020
  • The study of heat transfer coefficient of supercritical water plays an important role in improving the heat transfer efficiency of the reactor. Taking the supercritical natural circulation experimental bench as the research object, the effects of power, flow, pipe diameter and mainstream temperature on the heat transfer coefficient of supercritical water were studied. At the same time, the experimental data of Chen Yuzhou's supercritical water heat transfer coefficient was collected. Through the factorial design method, the influence of different factors and their interactions on the heat transfer coefficient of supercritical water is analyzed. Through the corresponding analysis method, the influencing factors of different levels of heat transfer coefficient are analyzed. It can be found: Except for the effects of flow rate, power, power-temperature and temperature, the influence of other factors on the natural circulation heat transfer coefficient of supercritical water is negligible. When the heat transfer coefficient is low, it is mainly affected by the pipe diameter. As the heat transfer coefficient is further increased, it is mainly affected by temperature and power. When the heat transfer coefficient is at a large level, the influence of the flow rate is the largest at this time.

Numerical Analysis for Integrity Evaluation of River Bank (하천제방의 건전도 평가를 위한 수치해석적 연구)

  • Jung, Hyuksang;Byun, Yoseph;Chun, Byungsik;Choi, Bonghyuck;Kim, Jinman
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.11
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    • pp.19-26
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    • 2010
  • An influence factors for soundness evaluation of river levee include consisting embankment in case piping, permeability coefficient of ground, height of embankment, the width of crest, material characteristics of embankment and foundation ground, shape of embankment slope, an influence for penetration of rainfall or river water in case slope stability. In this study, it was operated a feasibility investigation of existing design result, stability evaluation for permeability coefficient use and permeability coefficient change of foundation ground to investigate an influence in line with permeability coefficient change for result of river levee penetration analysis. The evaluation results of influence factors, the permeability coefficient was used in design and it was evaluated influence in safety factor of piping. After the evaluation of influence factors, the permeability coefficient used in the design appears with the fact that differs in a design report about same soil.

The Effect of Atmospheric Flow Field According to the Radius Influence and Nudging Coefficient of the Objective Analysis on Complex Area (자료동화의 영향반경과 동화강도가 복잡지형 기상장 수치모의에 미치는 영향)

  • Choi, Hyun-Jung;Lee, Hwa-Woon;Sung, Kyoung-Hee;Kim, Min-Jung
    • Journal of Environmental Science International
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    • v.18 no.3
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    • pp.271-281
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    • 2009
  • In order to reduce the uncertainties and improve the air flow field, objective analysis using observational data is chosen as a method that enhances the reality of meteorology. To improve the meteorological components, the radius influence and nudging coefficient of the objective analysis should perform a adequate value on complex area for the objective analysis technique which related to data reliability and error suppression. Several numerical experiments have been undertaken in order to clarify the impacts of the radius influence and nudging coefficient of the objective analysis on meteorological environments. By analyzing practical urban ground conditions, we revealed that there were large differences in the meteorological differences in each case. In order to understand the quantitative impact of each run, the Statistical analysis by estimated by MM5 revealed the differences by the synoptic conditions. The strengthening of the synoptic wind condition tends to be well estimated when using quite a wide radius influence and a small nudging coefficient. On the other hand, the weakening of the synoptic wind is opposite.

Free Vibration Analysis of Disk Structure by the Transfer Influence Coefficient Method (전달영향계수법에 의한 원판구조물의 자유진동해석)

  • ;末岡淳男;近騰孝廣
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.5
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    • pp.1439-1446
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    • 1991
  • 본 연구에서는 동적영향계수의 축차전달에 그 개념을 두고 있는 전달영향계수 법을, 2층 원판구조물의 자유진동해석애 적용해서, 그 알고리즘을 정식화 하고 전달매 트릭스법과 비교 검토하였다.