• Title/Summary/Keyword: inflection

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Nonlinear numerical simulation of RC columns subjected to cyclic oriented lateral force and axial loading

  • Sadeghi, Kabir
    • Structural Engineering and Mechanics
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    • v.53 no.4
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    • pp.745-765
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    • 2015
  • A nonlinear Finite Element (FE) algorithm is proposed to analyze the Reinforced Concrete (RC) columns subjected to Cyclic Loading (CL), Cyclic Oriented Lateral Force and Axial Loading (COLFAL), Monotonic Loading (ML) or Oriented Pushover Force and Axial Loading (OPFAL) in any direction. In the proposed algorithm, the following parameters are considered: uniaxial behavior of concrete and steel elements, the pseudo-plastic hinge produced in the critical sections, and global behavior of RC columns. In the proposed numerical simulation, the column is discretized into two Macro-Elements (ME) located between the pseudo-plastic hinges at critical sections and the inflection point. The critical sections are discretized into Fixed Rectangular Finite Elements (FRFE) in general cases of CL, COLFAL or ML and are discretized into Variable Oblique Finite Elements (VOFE) in the particular cases of ML or OPFAL. For pushover particular case, a fairly fast converging and properly accurate nonlinear simulation method is proposed to assess the behavior of RC columns. The proposed algorithm has been validated by the results of tests carried out on full-scale RC columns.

The Influence of Initial Overloads on the Fatigue Life of Spot-welded Tensile-shear Specimens (初期 過荷重이 點熔接 引張剪斷 試驗片의 疲勞擧動에 미치는 影響)

  • 강성수;정원욱
    • Journal of Welding and Joining
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    • v.13 no.2
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    • pp.60-67
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    • 1995
  • The factors affecting on the fatigue strength of spot_welded specimens have been studied. The influence of initial overloads on the fatigue life of spot_welded tensile_shear specimens is investigated by considering fatigue crack initiation and crack propagation. The change of strain range and the influence of initial overload are correlated on the basis ol strain results. The results of this study are as follows. l) The initial absolute strain range decreased with initial overloads increase, and absolute strain range decreased before transformation of waveform of strain, but increased after transformation of waveform of strain. 2) In case of subsequent point of inflection of offset strain, the increment of this strain decreased with initial overload increase. 3) As initial overloads increase, the deformation behavior of spot welded parts is restricted after overloading.

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Temperature and Atmosphere Dependence of the Electrical Conduction of the Vacuum Evaporated Thin Metal Films on Glass Substrate (진공증착된 금속박막의 전기전도성에 대한 온도와 분위기 의존성)

  • 김명균;박현수
    • Journal of the Korean Ceramic Society
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    • v.28 no.6
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    • pp.437-442
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    • 1991
  • Temperature and atmosphere dependence of electrical conduction of the metal Cu, Ag, Au films, vaccum evaporated on glass, was investigated. The structural changes of the metal films were examined by SEM and high temperature XRD. The electrical resistance slightly increased with initial temperature increase up to the inflection point and decreased to minimum value, after this rapidly increased with further temperature increased below minimum. These phenomena were caused by the thermally induced film failure as a result of the mass transport. The temperature for the film failure increased in the order of O2, Air, Vacuum, N2, Ar in Cu, Ag films and Air, Vacuum, N2, Ar in Au film. The increase of resistance at the lower temperature range was attributed to the lattice distortion by disordered crystal structure, while the decreasing resistance was attributed to the removal of structural defects and film densification.

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Efficiency of Vitrification using Conventional Straw and Grid as a Vihicle in Mouse Oocytes (마우스 성숙난자의 Straw와 Grid를 이용한 유리화동결법의 효율성 검토)

  • 정형민;박이석;박성은
    • Journal of Embryo Transfer
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    • v.16 no.3
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    • pp.233-237
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    • 2001
  • To develop an effective vitrification method, we examined the use of a conventional straw as vessel fur vitrification of mouse oocytes, and to compare the post-thaw survival and chromosome configuration of these oocytes with those vitrified in grids. Intact cumulus-enclosed oocytes were vitrified with DPBS with 5.5 M ethylene glycol and 1.0 M sucrose, and loaded into straws and onto eletron microscopic copper grid fur storing in liquid nitrogen. Intact vitrified and thawed oocytes were karyotying for chromosome. The rates of post-thawed survival were 88.5% in vitrified oocytes with straws, and 83% in vitrified ooctyes with grids. Vitrified and thawed oocytes with straws and grids were increased chromosomal abnormality (31.4% and 30.9%) compared with fresh oocytes (17.8%). The conventional straws can be used as vessel for vitrification to prevent of inflection in liquid nitrogen.

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Experimental Study on the Aerodynamic Performance Characteristics of a Small-Size Axial Fan with the Different Depths of Bellmouth (벨마우스 깊이가 다른 소형축류홴의 공력특성에 대한 실험적 연구)

  • Kim, Jang-Kweon;Oh, Seok-Hyung
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.73-78
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    • 2013
  • A Small-size axial fan(SSAF) has widely been utilized to circulate a cooling air in a refrigerator, etc. Generally, the aerodynamic performance of SSAF is strongly dependent upon the depth between SSAF and bellmouth, and it includes axial, partially stalled, mostly stalled and radial flow regions according to the flow coefficient. In this study, four kinds of bellmouth depths were considered to analyze the aerodynamic performance of SSAF. As a bellmouth depth increases, a maximum flowrate decreases, but a maximum static pressure increases. Also, stall region includes an inflection point in all aerodynamic performance curves. Finally, a static pressure efficiency shows the maximum value of 37%.

A study on the parameter estimation of S-Shaped Software Reliability Growth Models Using SAS JMP (SAS JMP를 이용한 S형 소프트웨어 신뢰도 성장모델에서의 모수 추정에 관한 연구)

  • 문숙경
    • Journal of Korean Society for Quality Management
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    • v.26 no.3
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    • pp.130-140
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    • 1998
  • Studies present a guide to parameter estimation of software reliability models using SAS JMP. In this paper, we consider only software reliability growth model(SRGM), where mean value function has a S-shaped growth curve, such as Yamada et al. model, and ohba inflection model. Besides these stochastic SRGM, deterministic SRGM's, by fitting Logistic and Gompertz growth curve, have been widely used to estimate the error content of software systems. Introductions or guide lines of JMP are concerned. Estimation of parameters of Yamada et al. model and Logistic model is accomplished by using JMP. The differences between Yamada et al. model and Logistic model is accomplished by using JMP. The differences between Yamada et al. model and Logistic model is discussed, along with the variability in the estimates or error sum of squares. This paper have shown that JMP can be an effective tool I these research.

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A Study of the Direction on Wordless Comics Inflection as The Transition (장면전환으로서 '글 없는 만화연출'의 활용 연구)

  • Lee, Won-Seok;Yoon, Gi-Hyuen
    • Cartoon and Animation Studies
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    • s.12
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    • pp.13-26
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    • 2007
  • The wordless comics means comics without word and only the image. The study treats the research and the analysis on the wordless comics as the transition. The degree of study are the wordless comics is used as transition with material and scene, with subject and narrative and so on. These practical use of the wordless comics influence how much dramatic effect with comics rather than text comics.

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A Study on the Concept and Spatial Organization of Bifurcation (분기(Bifurcation)의 개념과 공간조직에 관한 연구)

  • Kim Jong-Jin
    • Korean Institute of Interior Design Journal
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    • v.14 no.1
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    • pp.20-27
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    • 2005
  • This study is focused on the concept and spatial organization of bifurcation. After discussing the concept of bifurcation used in Borges' literature and Deleuze's Fold philosophy, case examples in contemporary architecture are analysed to comparatively investigate the relationship between the concept and space. In Deleuze's philosophy, bifurcation as well as pleats, inflection are used to form the world of fold that goes to infinity while, in Borges' literature, the structure of bifurcation is the key method to create the labyrinth of time. There are various projects in contemporary architecture based on the Deleuzian concept of bifurcation. Rem Koolhaas's Two Libraries for Jussieu University and UN Studio's Arnhem Central are selected and researched for further comparison study. In Jussieu project, the bifurcating spatial organization is 'intentionally' used to construct the indeterminant space whereas in Arnhem Central, bifurcation can be found in both the ever-bifurcating design process as well as the final spatial organization'unintentionally'generated from the process. This study is concluded with the comparative analysis between the representation and actualization of a concept that are crucially different.

A GENETIC ALGORITHM BY USE OF VIRUS EVOLUTIONARY THEORY FOR SCHEDULING PROBLEM

  • Saito, Susumu
    • Proceedings of the Korea Society for Simulation Conference
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    • 2001.10a
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    • pp.365-370
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    • 2001
  • The genetic algorithm that simulates the virus evolutionary theory has been developed applying to combinatorial optimization problems. The algorithm in this study uses only one individual and a population of viruses. The individual is attacked, inflected and improved by the viruses. The viruses are composed of flour genes (a pair of top gene and a pair of tail gene). If the individual is improved by the attacking, the inflection occurs. After the infection, the tail genes are mutated. If the same virus attacks several times and fails to inflect, the top genes of the virus are mutated. By this mutation, the individual can be improved effectively. In addition, the influence of the immunologic mechanism on evolution is simulated.

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Characteristics of the Momentum Equation in Open Channel Flow (개수로흐름 해석에서 운동량방정식의 특성)

  • Jeon, Min-Woo;Cho, Yong-Soo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.1111-1115
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    • 2008
  • The relative magnitudes of the individual terms of the momentum equation are analyzed and compared by the analytical methods in open channel flow. The temporal variations of each term(local acceleration term, convective acceleration term, pressure force term, gravity force term, and friction force term) are analyzed for the influence factors to runoff expressed by the parameters of the momentum equation, stream slopes and roughness coefficients. The magnitudes of each term vary with the channel characteristics, especially when the roughness coefficients are dominant or for the mild stream slopes the pressure term can not be negligible. As a result of the characteristics of momentum equation in open channel flow, the acceleration terms are very small compared with the other terms. The magnitudes of local acceleration and convective acceleration offsets each other. The peak time of each term except the gravity term coincides with inflection point of the hydrograph rising limb each other.

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