• 제목/요약/키워드: double scale model

검색결과 126건 처리시간 0.029초

만곡수로에서 2차원 흐름해석 (A Two Dimensional in Bended Open Channel Flows)

  • 윤세의;이종태;이원환
    • 대한토목학회논문집
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    • 제6권1호
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    • pp.87-94
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    • 1986
  • 일반적으로 자연하천은 수심에 비해 하폭이 크고 완만한 곡률을 나타내므로 2차원 수치모형이 실용적인 것으로 알려져 있다. 본 연구에서는 만곡수로의 흐름특성을 분석하기 위하여 2차원 부정류의 운동방정식과 연속방정식을 차분화하고 Double Sweep 알고리즘에 의한 수치해석모형을 개발하였다. 본 모형의 적용성을 입증하기 위해 L.F.M 실험수로 및 I.I.H.R 실험수로의 실측치와 비교하여 비교적 잘 일치함을 확인할 수 있었다. 벽면마찰의 영향을 감소시키기 위하여 Chezy 계수의 적절한 조정으로 실측치에 더욱 접근된 결과치를 얻을 수 있었으며, 이류항의 영향을 분석하였다. 만곡수로내의 수면형태, 최대유속선이 이동경로 및 깊이방향 평균유속의 크기와 방향을 계산할 수 있었다.

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나노 스케일 MuGFET의 소자 구조 최적화에 관한 연구 (A study on the device structure optimization of nano-scale MuGFETs)

  • 이치우;윤세레나;유종근;박종태
    • 대한전자공학회논문지SD
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    • 제43권4호
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    • pp.23-30
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    • 2006
  • 본 연구에서는 나노 스케일 MuGFET(Mutiple-Gate FETs)의 단채널 효과와 corner effect를 3차원 시뮬레이션을 통하여 분석하였다. 문턱전압 모델을 이용하여 게이트 숫자(Double-gate=2, Tri-gate=3, Pi-gate=3.14, Omega-gate=3.4, GAA=4)를 구하였으며 추출된 게이트 숫자를 이용하여 각각의 소자 구조에 맞는 natural length($\lambda$)값을 얻을 수 있었다. Natural length를 통하여 MuGFET의 단채널 효과를 피할 수 있는 최적의 소자 구조(실리콘 두께, 게이트 산화막의 두께 등)를 제시 하였다. 이러한 corner effect를 억제하기 위해서는 채널 불순물의 농도를 낮게 하고, 게이트 산화막의 두께를 얇게 하며, 코너 부분을 약 17%이상 라운딩을 해야 한다는 것을 알 수 있었다.

축소 모델을 이용한 수동 루프 송전선 자기장 저감율 분석 (Analysis of ELF Magnetic Field Reduction Ratio on Passive Loop Using Scale Down Model of Transmission Line)

  • 조연규;명성호;이재복;장석훈
    • 한국전자파학회논문지
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    • 제17권12호
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    • pp.1231-1239
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    • 2006
  • 본 연구는 수동 루프 축소 시험 장치를 이용하여 수동 루프 유형별 자기장 저감 효과를 분석하였다. 본 연구에서는 수직 2회선 선로 및 수평 선로를 대상으로 실험을 통하여 향후 실증 시험 선로에 적용할 수동 루프의 자기장 저감 효과를 검토하였다. 그 결과 수동 루프 채용으로 선로 리액턴스 보상이 없어도 50 % 이상의 송전 선로의 자기장 저감 효과를 얻을 수 있음을 확인함으로써 실증 선로 수동 루프 적용 방안을 확보하였다. 대부분 우리나라 송전 선로에 채용되는 수직 2회선 선로에서는 수평 루프보다는 수직 루프가 자기장 저감율에 보다 효과적이었으며 차폐 영역에서도 근거리뿐만 아니라 원거리까지도 효과가 좋음을 알 수 있었다. 또한, 수동 루프를 3 턴으로 설치하는 경우가 1 턴에 비해 2배정도 자기장 저감 효과가 있음을 확인하였다.

자기 검색척도(Self-Monitoring Scale)의 타당성 검정에 관한 연구 (The Study of the Validity Test on the Self-monitoring Scale)

  • 이선아
    • 대한간호학회지
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    • 제28권3호
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    • pp.751-759
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    • 1998
  • The study of the validity test on the self-monitoring scale for nurses In this study, both the literary survey as well as empirical research has been executed to test the validity of the scales that measure the construct of the self-monitoring scale. The self-monitoring scale could not be classified into five factors as Snyder suggested. Many other scholars (Briggs, Cheek and Buss, 1980) suggested 3 different classifications which was accepted by Snyder and Gangestad (1986). John, Cheek and Klohnen(1996) claimed a two-factor classification. As has been discussed, factor analysis is used to prove convergent validity within the factor and discriminant validity between the factors. However, depending on the researchers, many variations in classification of the factors were found and a lack of content and discriminant validity were found in the previous research findings. It is also important to note that Snyder's self-monitoring scale did not factor-load at over. 30 for all 25 items, regardless of how many factors could be classified. According to findings of this study, the self-monitoring scale neither classified as five, three or two factors nor factor loaded as hypothesized. It is also clear that Snyder's self-monitoring scale lacks convergent validity as the sub-factors of the scale failed to prove its uni-dimensionality. The A self-monit oring scale not only fail to overcome the problems of Snyder's self-monitori ng scale but even lost the attractiveness of the self-monitoring scale. In this study it was also found that the A self-monitoring scale was not classified in either in a two or three-factor classification as hypothesized. It is, of course, not desirable to use any scale that lacks convergent and discriminant validity even though it has been widely used and has held a great deal of influence on the field of social psychology. To overcome the shortcomings of Snyder's self-monitoring scale, Lennox and Wolfe(1984) suggested 13 items. This study was dedicated to test the validity and reliability of the scale, in which we found that the data presented in validity as the two factors were class ified and loaded as expected. Reliability was also proven by checking Cronbach's α for each factor and for the total items. In addition, a confirmatory factor analysis was executed for the 13 items using LISREL 8.12 program to confirm convergent validity in a two-factor classification. The model was fitting and sound : however, the self-monitoring scale was unfitted and not validated. Thus, it is recommended to use not the original nor the abbreviated self-monitoring scale but the 13 items in future studies. It should also be noted that items 7 and 13 should be removed to obtain better uni-dimensionality for the 13 items. These items loaded at over. 30, too high for the two factors in the test results of Factor analysis. In addition, it is necessary to double-check the cause of two-hold loading at over .30 for the two factors. It could be a problem caused by data or by the scale itself. Therefore, additional studies should follow to better clarify this matter.

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초임부를 대상으로 한 자가검색도 척도의 타당도 비교 (Study of the Validity Test on the Self-monitoring Scale for Primi-Gravida)

  • 이선아
    • 여성건강간호학회지
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    • 제4권2호
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    • pp.173-186
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    • 1998
  • In this study, both the literary survey as well as empirical research has been executed to test the validity of the scales that measure the construct of self-monitoring scale could not be classified into five factors as Snyder suggested. Many other scholars (Briggs, Cheek and Buss, 1980) suggested 3 different classifications which was accepted by Snyder and Gangestad (1986). John, Cheek and Klohnen (1996) claimed a two-factor classification. As has been discussed, factor analysis is used to prove convergent validity within the factor and discriminant validity between the factors. However, depending on the researchers, many variations in classification of the factors were found and a lack of content and discriminant validity was found in the previous research findings. It is also important to note that Snyder's self-monitoring scale, did not factor-load at over 30 for all 25 items, regardless of how many factors could be classified. According to findings of this study, the self-monitoring scale neither classified as five, three or two factors nor factor loaded as hypothesized. It is also clear that Snyder's self-monitoring scale lack convergent validity as the sub-factors of the scale fail to prove its uni-dimensionality. The A self-monitoring scale not only fail to overcome the problems of Snyder's self-monitoring scale but even lost the attractiveness of the self-monitoring scale. In this study, it was also found that the A self-monitoring scale was not classified as hypothesized in either in a two or three-factor classification. It is, of course, not desirable to use any scale that lacks convergent and discriminant validity even though it has been widely used but also has held a great deal of influence on the field of social psychology. To overcome the shortcomings of Snyder's self-monitoring scale, Lennox and Wolfe(1984) suggested 13 items. This study 1. was dedicated to test the validity and reliability of the scale, in which we found that the data presented in validity as the two factors were classified and loaded as expected. Reliability was also proven by checking Cronbach's alpha for each factor and for the total items. In addition, a confirmatory factor analysis was executed for the 13 items using LISREL 8.12 program to confirm convergent validity in a two-factor classification. The model was fitting and sound ; however, the self-monitoring scale was unfitted and not validated. Thus, it is recommended to use not the original or the abbreviated self-monitoring scale but the 13 items in future studies. It should also be noted that items 7 and 13 should be removed to obtain better uni-dimensionality for the 13 items. These items loaded at over .30, too high for the two factors in the test results of factor analysis. In addition, it is necessary to double-check the cause of two-hold loading at over .30 for the two factors. It could be a problem caused by data or by the scale itself. Therefore, additional studies should follow to better clarify this matter.

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복층터널에서 도로용 중간슬래브와 연결되는 조립식 브라켓의 구조성능에 관한 실험연구 (A Experimental Study on the Structural Performance of Precast Bracket under Precast Road Deck Slab of Double Deck Tunnel)

  • 김보연;이두성;김태균;김영진
    • 대한토목학회논문집
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    • 제37권4호
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    • pp.647-657
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    • 2017
  • 이 연구에서는 대심도 복층터널을 구성하는 중간슬래브의 하중을 터널본체에 전달하는 브라켓 구조에 관한 정 동적 거동을 조사하였다. 시공속도 향상을 위해 중간슬래브를 프리캐스트 쉴드 터널라이닝 구조체에 연결하기 위한 현장 조립형 'SPC (Steel Precast Concrete) 브라켓'을 개발하였다. 'SPC (Steel Precast Concrete) 브라켓'의 구조 성능을 평가하기 위해서 실물모형 구조실험을 수행하였으며, Contact 모델을 적용한 FEM 해석을 통해서 구조적인 안정성을 추가로 검증하였다. 정적재하실험을 수행한 결과 극한하중에 대한 브라켓의 변형이나 균열은 계측되지 않았으며, 브라켓 고정용 케미컬 앵커의 뽑힘이나 변형은 발생되지 않았다. 동적재하실험 결과 케미컬 앵커의 이상은 조사되지 않았다. FEM해석에 따른 브라켓의 거동은 정적재하실험 결과와 유사한 거동을 보여 사용성 및 구조 안정성 측면에서 문제가 없다고 판단된다.

PIV 기법을 이용한 모형철도터널 직관덕트에서 유동 분포 계측 및 수치해석 결과와의 비교분석 (MEASUREMENT OF FLOW DISTRIBUTION IN A STRAIGHT DUCT OF RAILWAY TUNNEL MOCK-UP USING PIV AND COMPARISON WITH NUMERICAL SIMULATION)

  • 장용준;정우성;박일순
    • 한국전산유체공학회지
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    • 제15권3호
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    • pp.39-45
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    • 2010
  • The turbulent flows in a tunnel mock-up($10L{\times}0.5W{\times}0.25H$ m3 : scale reduction 1/20) with rectangular cross section were investigated. The instantaneous velocity fields of Re = 49,029, 89,571 were measured by the 2-D PIV system which is consisted of double pulsed Nd:Yag laser and the tracer particles in the straight-duct mock-up where the flows were fully developed. The mean velocity profiles were taken from the ensemble averages of 1,000 instantaneous velocity fields. Simultaneously, numerical simulations(RANS) were performed to compare with experimental data using STREAM code. Non-linear eddy viscosity model (NLEVM : Abe-Jang-Leschziner Eddy Viscosity Model) was employed to resolve the turbulent flows in the duct. The calculated mean velocity profiles were well compared with PIV results. In the log-law profiles, the experimental data were in good agreement with numerical simulations all the way to the wake region except the viscous sub-layer (near wall region).

중형 컨테이너선의 연료절감형 비틀림 타 개발 (Development of Twisted Rudder to Reduce Fuel Oil Consumption for Medium Size Container Ship)

  • 전호환;차경정;이인원;최정은
    • 대한조선학회논문집
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    • 제55권2호
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    • pp.169-177
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    • 2018
  • Twisted rudder, twisted rudder with bulb, and twisted rudder with bulb and fin have been developed computationally for 3,000 TEU container ship through parametric study. The objective function is to minimize delivered power in model scale. Design variables are twisted angle, rudder bulb diameter and fin angle. The governing equation is Reynolds averaged Navier-Stokes equations in an unsteady turbulent flow and the Reynolds stress model applied for the turbulent closure. A double body model is used for the treatment of free-surface. The calculation was carried out in towing and self-propulsion conditions at design speed. The sliding mesh technique was employed to simulate the flow around the propeller. Form factor is obtained from the towing computation. Self-propulsion point is obtained from the self-propelled computations at two propeller rotating speeds. The delivered power due to the designed twisted rudder, twisted rudder with bulb, and twisted rudder with bulb and fin are reduced by 1.1%, 1.6%, and 2.0%, respectively.

고등학생의 ADHD성향과 게임중독 간의 관계: 강인성과 정서적 음악사용의 매개효과를 중심으로 (The Relationship between ADHD Traits and Game Addiction among High School Students: Focused on Mediating Effect of Hardiness and Emotional Use of Music)

  • 박알렉산더
    • 한국콘텐츠학회논문지
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    • 제21권8호
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    • pp.571-579
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    • 2021
  • 본 연구의 목적은 고등학생의 ADHD성향과 게임중독 간의 관계를 확인하고, 그 관계를 강인성과 정서적 음악사용이 이중으로 매개하는지를 검증하는 것이다. 연구대상은 남녀 고등학생 254명이었다. 이 연구를 위해 세계보건기구의 자기보고식 ADHD척도, 단축형 강인성 질문지, 음악사용검사 및 인터넷 게임중독 선별검사를 사용하였다. 이중매개효과는 PROCESS Macro 3.5 모형 6으로 분석하였다. 연구 결과, 고등학생의 ADHD성향은 강인성과 부적 상관이, 정서적 음악사용이나 게임중독과는 정적 상관이 있었다. 고등학생의 강인성은 정서적 음악사용과는 정적 상관이, 게임중독과는 부적 상관이 있었는데, 정서적 음악사용은 게임중독과 부적 상관이 있었다. 본 연구에서는 고등학생의 ADHD성향과 게임중독 간의 관계를 강인성과 정서적 음악사용이 직렬로 이중매개 하는 것으로 나타났다. 이런 결과는 청소년의 ADHD성향이 게임중독에 영향을 미치는 경로에서 강인성과 정서적 음악사용이 의미 있는 역할을 한다는 것을 시사한다.

Problems of Using Cyberdramaturgy in Modern Foreign Cinematography

  • Portnova, Tatiana V.
    • International Journal of Computer Science & Network Security
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    • 제22권10호
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    • pp.25-30
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    • 2022
  • The article is devoted to the actual problem of the use of digital technologies in modern cinema in developed countries. The purpose of the study is to identify the essence of the term "cyberdramaturgy" and the problems of its use in modern film production. The research methodology is based on a systematic approach and includes the methods of the general scientific group (analysis, synthesis, deduction, induction), as well as a number of special methods: the method of content analysis of scientific literature on the research topic; sociological survey method; as well as the method of statistical analysis. The results of the survey were analyzed using the Neural Designer program (a tool for advanced statistical analytics) and translated into a graphical diagram format for clarity of perception. Answers in 75 questionnaires were evaluated by the average score for six analysis criteria, which made it possible to bring all the calculations to a 10-point scale. As a result of the study, the author of the article concluded the following: directors believe that the use of cyber analogues of actors and backgrounds leads to the blurring of genres, the hybridization of cinema and animation; directors are also concerned about the problem of replacing the director himself with a special program. The writers are completely concerned with the problem of machine scripting with almost infinite variability beyond the human imagination. Directors-producers believe that the cyberdramaturgy development will lead to completely new standards of cinematic quality, sharply different from the traditional assessment of acting and scene setting, to the appreciation of 3D animation as the highest category in the art. Such innovations actually devalue all international cinematography awards, as cyberdrama reduces the value of cyberactors to zero. It is impossible to bail out an "Oscar" or a "Golden Globe" award for a digital double or a separate cyber model that is used in the film instead of the actors.