• Title/Summary/Keyword: Size effect

Search Result 12,580, Processing Time 0.053 seconds

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

  • Kim S. H.;Huh H.;Hahn H. Thomas
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2005.05a
    • /
    • pp.167-170
    • /
    • 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.

  • PDF

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

  • Kim, Song Hee;Kim, Ae Jung
    • Journal of the Korean Dietetic Association
    • /
    • v.26 no.2
    • /
    • pp.153-173
    • /
    • 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.

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

  • Kim, Ilsik;Kim, Gyeryung;Shin, Hyesook;Seo, Hochan
    • Journal of Family Relations
    • /
    • v.21 no.2
    • /
    • pp.3-23
    • /
    • 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.

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

  • Kim, Eun-Joo;Lee, So-Young;Kim, Ae-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.21 no.11
    • /
    • pp.273-282
    • /
    • 2020
  • This study analyzed the physiological effects of silkworms and silkworm pupae on the reduction of serum lipid levels. Research data specific to silkworms and their pupae published over the last 10 years were collected and analyzed. A large effect size of 0.852 was observed in the overall results and the range of 95% confidence intervals was 0.662 to 0.999. The Q value was 23.264, the Higgin's I2 value was 92.217, indicating that each study was heterogeneous. There was no publication bias, as the corrected observed number of statistically significant effect sizes and the expected number of statistically significant effect sizes were both 0.654. The silkworm study showed a large effect size with respect to blood sugar and blood lipid reduction at 0.801 and 0.948, respectively, and LDL-cholesterol reduction at 1.371, showing a very large effect size. Aspartate transaminase / glutamic oxaloacetic transaminase (AST/GOT) was 0.768, alanine transaminase /glutamate-pyruvate transaminase (ALT/GPT) was 0.788, which was a medium effect size. The experiment period had a very large effect size of 1.170 for five to eight weeks and 1.020 for an intake of 1 to 50 mg/kg. The silkworm pupae had a large effect size of 0.991 and 0.951, respectively on blood lipids and total cholesterol reduction. The experimental period showed a very large effect size at 1.103 for more than nine weeks, and the intake showed a large effect size at 0.855 for 5001 mg/kg.

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

  • Kim, Ilsik;Kim, Gyeryung;Lee, Su-kyung;Seo, Hochan
    • 한국노년학
    • /
    • v.38 no.1
    • /
    • pp.65-82
    • /
    • 2018
  • The purpose of this study is to statistically summarize the effect sizes using meta-analysis of various Kigong programs implemented on the subject of physical health of the elderly. Including 23 academic journal studies and 11 thesis studies reported domestically until 2016, a total of 34 studies were selected and analyzed to verify the effect sizes of programs, program types, measuring variables, and activity elements. The findings are as follows. First, it was found that the programs were midium effective with overall average effect size showing .748(p<.001). A program of Tai-Chi indicated the largest effect size of .836(p<.001). In terms of measuring variables, physical strength showed the largest effect size of .806(p<.001). In terms of gender by group, it was found that groups consisting only of men indicated the largest effect size of 2.388(p<.001). As for effect size by group of disease state, normal group with showed the highest effect size of .804(p<.001). Second, in activity elements, 31~60 by the group size has the largest effect size of .873(p<.001), total number of sessions for 31~40 sessions indicated the largest effect value of .829(p<.001). As for number of sessions per week, 5 sessions showed largest effect value of .918(p<.001), in terms of activity time, 50 minutes showed large effect value of 1.391(p<.001). As summarized above, Kigong programs are midium effective for physical health of the elderly, as an activity elements to consider when configuring the program, for group size 31~60, 31~40 sessions in total, 5 sessions per week and 50 minutes per sessions were recommended.

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

  • Lee, Hyo-Jin;Oh, Hee-Hwa;Choi, Kyoung-Ho
    • Journal of the Korean Data and Information Science Society
    • /
    • v.23 no.3
    • /
    • pp.447-455
    • /
    • 2012
  • The purpose of this study is to examine the effect of reading development program on reading comprehension using meta-analysis method. The authors synthesized 70 studies regarding reading comprehension conducted during 2001 through 2011. The analyses revealed that 1) the average effect size of the reading development program yielded.763, which is regarded considerably large, 2) the effect size of elementary school group was the biggest, 1.030. There were statistically significant differences amongst school levels, 3) the average effect size of published journal articles was 1.250, which is statistically significantly larger than that of dissertation's.700, 4) regarding the methods to measure the effect of reading comprehension, the effect size of reading method was larger, and 5) the effect size of Korean reading development program was statistically larger than that of English reading development program. This study has limitation as it didn't include unpublished manuscripts, conference presentations, and the like, however this study is meaningful in terms that it tried to draw integrated conclusion about the effect of reading development programs using meta-analysis.

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
    • /
    • v.8 no.2
    • /
    • pp.112-123
    • /
    • 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.

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

  • 채영훈;김석삼
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.217-222
    • /
    • 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.

  • PDF

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

  • Ahn, Kwan-Young
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.35 no.1
    • /
    • pp.154-160
    • /
    • 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
    • /
    • v.7 no.3
    • /
    • pp.861-873
    • /
    • 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.