• 제목/요약/키워드: Size effect

검색결과 12,567건 처리시간 0.042초

입자보강 복합재료에서 크기효과 -Size-Dependent 소성역학 (The Size Effect in Particulate Composite Materials - Size - Dependent Plasticity)

  • 김승호;허훈
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 춘계학술대회 논문집
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    • pp.167-170
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    • 2005
  • This paper briefly reviews various existing methods to account for the effect of particle size on mechanical properties of particulate metal matrix composites. A simple and easy method is to use a size-dependent constitutive equation for the matrix. The suggested method does not require the development of a new computational algorithm and is compatible with any standard finite element software. Finite element analyses have been carried out to show how the deformation behavior of a metal matrix composite changes as the particle size and volume fraction are varied.

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미취학아동 대상 영양·식생활교육의 효과 메타분석 (Meta-Analysis of the Effects of Nutrition & Dietary Life Education for Preschoolers)

  • 김송희;김애정
    • 대한영양사협회학술지
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    • 제26권2호
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    • pp.153-173
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    • 2020
  • The purpose of this study was to objectively quantify the effects of nutrition and dietary life education on preschoolers through meta-analysis. In addition, it provides basic data for the implementation of nutrition education and development of systematic nutrition and dietary life education programs. In this study, a meta-analysis of 27 papers was conducted that conformed to the selection criteria in the study conducted from January 2012 to August 2019 to derive objective data on the effects of education. As a result of the analysis, the overall effective size of nutrition and dietary life education for preschoolers was 0.829, which indicates a strong effect. According to the education method, the effect size of general education was 0.562, which indicates a medium effect size, the vegetable playing-based experience education was 0.685, which indicates a medium effect size, and cooking activity-based experience education was 1.101, which indicates a large effect size. Judging from this result, experience activity education was more effective than general nutrition education. In addition, the combined size of convergence education conducted through a combination of general and experience education was found to be the most effective at 1.301. In terms of educational effect, it was confirmed that the effect size was 0.898 for improving nutrition knowledge, 0.858 for improving dietary habits, 0.836 for improving unbalanced diet, and 0.756 for improving food preference and intake, and the sizes of effects were all found to be large. As frequency of education increased, the number of education participants decreased and the effect of education increased.

죽음준비교육 프로그램 효과성에 대한 메타분석 (A meta-analysis of effectiveness of death education program)

  • 김일식;김계령;신혜숙;서호찬
    • 한국가족관계학회지
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    • 제21권2호
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    • pp.3-23
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    • 2016
  • Objectives: The purpose of this study is to conduct a meta-analysis of results of death education program implemented with a wide range of learners from preschoolers to the elderly and use the findings to suggest effect sizes of the intervention program, variables, and measurement tools and activity elements of the variables. Method: Among preceding studies conducted domestically until 2015, 21 studies that meet the meta-analysis criteria were selected and analyzed using CMA(Comprehensive Meta-Analysis 3.0 version). Results: The findings are as follows. The overall average effect size was rather large at 0.997. Reviewing by research subject group, victims of domestic violence indicated the largest effect size(2.381). As for variables, death awareness showed the largest effect size(2.908). In terms of activity elements, the largest effect size for total number of sessions was 16 sessions (4.972), while that for per week sessions was 2 sessions/week (2.327). With effect size for activity hours largest at 30 minutes(5.365) followed by 108 minutes(2.381) and 360 minutes(1.607), it was found that there is no positive relationship between activity time and effect size. In terms of publication type, effect size of academic journal paper was 1.107 while that of thesis or dissertation was 0.894, indicating that academic journal papers are relatively highly effective. Conclusions: The present study is meaningful in that it provides baseline data applicable to program development and implementation by verifying the effectiveness of domestically implemented death education programs and variables relevant to such programs.

누에와 누에번데기의 혈청지질에 미친 영향에 대한 메타분석 (Meta-Analysis on the Effect of Serum Lipids Levels in Silkworm and Silkworm Pupae)

  • 김은주;이소영;김애정
    • 한국산학기술학회논문지
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    • 제21권11호
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    • pp.273-282
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    • 2020
  • 본 연구는 경제적, 사회적, 환경적으로 가치가 있는 미래의 식량자원인 곤충식품의 산업적 활용도를 높이고자 최근 10년간(2009년~2019년) 발표된 곤충식품들 중 누에와 누에번데기의 생리활성 연구자료를 수집하여 혈청 지질 수준 개선에 대한 메타분석을 실시하였다. 누에와 누에번데기 연구물의 총 편수는 20편이었으며, 총 사례 수는 261개로 산출되었다. 연구단위로 분석한 연구의 수는 총 20개였다. 전체 연구결과의 효과크기는 0.852로 큰 효과크기였으며, 95% 신뢰구간의 범위는 0.662~0.999였다. Q 값은 23.264(p<0.001), Higgin's I2 값은 92.217로 각각의 연구가 이질성이 있다고 확인되었다. 관측값과 추정치를 보정한 관측값이 0.654로 동일하게 나타나 출판편향은 없었다. 누에 연구는 혈당과 혈중지질이 각각 0.801, 0.948로 큰 효과크기였으며, 그중 LDL-콜레스테롤은 1.371로 매우 큰 효과크기였다. 간 세포 손상(AST/GOT)은 0.768, 만성 간 세포 손상(ALT/GPT)은 0.788로 중간 효과크기였다. 실험기간은 5~8주가 1.170, 섭취량은 1~50 mg/kg이 1.020으로 매우 큰 효과크기였다. 누에번데기는 혈중지질과 총 콜레스테롤이 각각 0.991, 0.951로 큰 효과크기였다. 실험기간은 9주 이상이 1.103으로 매우 큰 효과크기였으며, 섭취량은 5001 mg/kg 이상이 0.855로 큰 효과크기를 보였다.

노인 신체건강을 위한 기공(氣功)프로그램 효과성 메타분석 (A Meta-analysis of Effectiveness of Kigong Programs for the Physical Health of the Elderly)

  • 김일식;김계령;이수경;서호찬
    • 한국노년학
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    • 제38권1호
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    • pp.65-82
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    • 2018
  • 본 연구는 노인의 신체건강을 주제로 수행된 다양한 기공프로그램에 대해 메타분석을 사용하여 효과크기를 통계적으로 요약해보고자 하였다. 2016년까지 국내에서 보고된 학술지 논문 23편과 학위 논문 11편 총 34편을 선정하여 프로그램과 프로그램의 유형, 측정변수 및 활동요소에 대한 효과크기를 확인한 결과, 첫째, 전체평균 효과크기는 .748(p<.001)로써 중간크기의 효과가 나타났다. 가장 효과크기가 큰 프로그램은 타이치로 .836 (p<.001)이었으며, 측정변수는 체력이 .806(p<.001)으로 가장 높게 나타났다. 집단의 성별에서는 남성만으로 구성된 집단이 2.388 (p<.001)로 높았고, 집단의 질병유무에 따른 효과크기는 정상집단이 .804(p<.001)로 높게 나타났다, 둘째, 활동요소 중 집단크기는 31~60명이 .873(p<.001), 총회기수는 31~40회가 .829(p<.001)로 높게 나타났다. 주회기수는 5회가 .918(p<.001)로 가장 높았고, 활동시간에 따른 효과크기는 50분이 1.391(p<.001)로 높은 효과크기를 보였다. 상기와 같이 기공프로그램은 노인의 신체건강에 중간크기의 효과가 나타났으며, 향후 기공프로그램 구성 시 집단크기 31~60명, 총회기수 31~40회, 주회기수 5회, 활동시간은 50분으로 제안하고자 한다.

독해력 증진 프로그램 효과에 대한 메타분석 (Meta analysis on the effect of reading development program on reading comprehension)

  • 이효진;오희화;최경호
    • Journal of the Korean Data and Information Science Society
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    • 제23권3호
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    • pp.447-455
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    • 2012
  • 본 연구의 목적은 메타분석법을 이용하여 독해력 증진 프로그램의 효과를 분석하는 것이다. 이를 위해 2001년부터 2011년까지 연구된 독해력 관련 연구 70편을 종합한 효과크기를 산출하였으며, 이를 토대로 다음과 같은 연구결과를 얻었다. 첫째, 독해력 증진 프로그램 효과에 대한 평균 효과크기는 0.763으로 큰 편이었다. 둘째, 초등학교의 효과크기가 1.030으로 가장 큰 가운데, 학교 급간에는 통계적으로 유의한 차이가 있었다. 셋째, 학술지의 평균 효과크기가 1.250으로 학위논문의 평균 효과크기인 0.700 보다 통계적으로 유의하게 더 큰 것으로 나타났다. 넷째, 효과 측정방법에 대해서는 읽기방법의 효과크기가 더 컸으며, 다섯째, 적용언어에 대해서는 한국어가 영어보다 유의적으로 더 큰 것으로 나타났다. 본 연구를 수행하는 과정에서 미발표된 연구결과물을 포함시키지 못한 점은 본 연구의 한계이다. 그러나 메타분석을 활용하여 독해력 증진 프로그램의 효과에 대한 통합적인 결과를 도출하려는 시도는 나름대로 의의를 갖는다고 하겠다.

Effect of aquatic exercise on gait in persons with chronic stroke: a meta-analysis study in Korea

  • Lee, Dong-Jin;Cho, Sung-Hyoun
    • Physical Therapy Rehabilitation Science
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    • 제8권2호
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    • pp.112-123
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    • 2019
  • Objective: Based on the results of previous studies, it is necessary to analyze gait and discuss and present the effects of aquatic exercise for chronic stroke. The purpose of this study was to present objective data on the effect of aquatic exercise on the gait of persons with stroke by performing a meta-analysis. Design: A systematic review and meta-analysis. Methods: We performed a meta-analysis of 23 studies that investigated the effects of aquatic exercise performed between 2006 and 2017. The studies were searched on the basis of the participants, intervention, comparison, outcomes standard. The quality of the research method was assessed using a tool that can assess the risks posed by each study design. A meta-analysis software program was used to calculate the mean effect size, effect size by intervention, and effect size by outcome. We also performed a meta-regression analysis and an analysis of publication bias. Results: The mean effect size of the patients' gait was 0.65 (p<0.05). The largest effect size by outcome was observed at the 6-m walk test, followed by the 6-minutes walk test, 10-m walk test, and the walking equipment test (p<0.05). The meta-regression analysis showed that the effect size increased with increased duration, number, and length of sessions. Conclusions: Aquatic exercise appears to show a moderate effect on the gait of chronic stroke survivors. Meta-analyses on the effects of aquatic exercise in other patient populations are needed. This study suggests standard criteria establishments for the effect of aquatic exercise on the walking ability of persons with chronic stroke.

Photolithography 를 이용한 micro-dimple 크기에 따른 미끄럼 마찰거동 (The effect of size on friction property of micro-dimple surface to fabricate by photolithography)

  • 채영훈;김석삼
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.217-222
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    • 2004
  • The aim of this paper is to investigate the effect of micro-dimple size on reduction friction and to understand the potential of friction reduction through micro-scale dimple to fabricate by photolithography on pin-on-disk test using flat-on-flat contact geometry. It was verify that the friction property with respect to the same pitch has been influence on the size of dimple under lubricated sliding contact. Also, we can recognize from Stribeck curve that the friction property has a connection with the size of dimple. It can explain a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. The friction property has been an effect on the size of surface texture on reduction friction, not only because the density of dimple, but also because the ratio of diameter/pitch. This ratio of approximately 0.5 is recommend under the tested friction condition. It suggested that the ratio of d/p is an important parameter for surface texture design.

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중소기업의 지식경영이 구성원의 혁신활동에 미치는 효과 (The Effect of Knowledge Management on the Innovation Activities of Employee in Small Business)

  • 안관영
    • 산업경영시스템학회지
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    • 제35권1호
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    • pp.154-160
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    • 2012
  • This paper reviewed the two proposed hypotheses. The first hypothesis is to test the relationship between knowledge management and incremental innovation, and the second hypothesis is to test the moderating effect of firm-size on that relationship. Data were gathered from 434 employees in service industry, and multiple regression analysis was used to test two proposed hypotheses. In the first hypothesis, it was appeared that knowledge acquisition and knowledge transfer have positive effects on all incremental innovation factors (process innovation, operation innovation, service innovation). In the second hypothesis, it was appeared that firm-size has an positive interaction effect on incremental innovation in knowledge transfer, but not in knowledge acquisition. It means that knowledge transfer has more positive effect on incremental innovation in large firm-size than in small firm-size.

EFFECT OF THE NUMBER OF ACTIVE SOURCES ON ABR BUFFER SIZE

  • Lee, Yu-Tae;Han, Dong-Hwan
    • Journal of applied mathematics & informatics
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    • 제7권3호
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    • pp.861-873
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    • 2000
  • Rate-based flow control plays an important role for efficient traffic management of Available Bit Rate(ABR) services. We deal with the problem of the buffer dimension for rate-based ABR control. In this paper, we analyze the Allowed Cell Rate(ACR) of a source and the queue size in a steady state. First, we investigate the effect of the number of active sources on the behavior of the ACR and the maximum queue size. Reflecting the effect of this real scenes, we determine the optimal buffer size and buffer threshold. Furthermore, our analytic results are compared with the case when the effect of the number of active sources is disregarded.