• Journal of Welding and Joining
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• v.1 no.2
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• pp.61-68
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• 1983

Austenitic stainless steel has been investigated widely for creep strength of heat resistant material and effects of grain sizes due to various solution treatment time under constant temperature. It was studied that effects of grain sizes subject to solution treatment temperature 1100.deg. C, 1125.deg. C, 1175.deg. C, 1250.deg C, and 1300.deg. C respectively on the creep strength, fracture behaviour and fractography of SUS 316 stainless steel. The experimental results obtained were as follows. 1. The optimum grain size for the maximum creep strength did not vary with creep testing temperatures and stress levels. 2. Among various grain sizes due to different solution treatment temperature, the optimum grain size for the creep strength was found 0.044mm. Also the size showed the minimum initial strain regardless creep temperature. 3. Garofalo's equation of creep rupture life was applied well to SUS 316 stainless steel. 4. The fractography of optimum size was ductile intergranular fracture of dimple type and showed along with the increase of grain size intergranular fracture of w type.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.4
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• pp.292-298
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• 2020

The effects on the size selectivity for Muraenesox cinereus caught by coastal longline fishery were investigated in the southern coast of Korea from June 2 to 17, 2019. Four sizes of hooks (sizes 15, 17, 18 and 19) and two sizes of bait (sizes 9.9 g and 18.3 g) were tested in seven and three fishing trials, respectively. Such results revealed that smaller hook and bait size improved capture efficiency. And our results demonstrate that there was no significant size selectivity effect for hook size (ANOVA, p>0.05), but small bait improved on catching smaller fish (ANOVA, p<0.05).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.352-359
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• 2012

For rebuilding and managing fish stocks and fisheries, the biological and socioeconomic evaluations on fisheries management regulations are important. This study aimed to estimate the economic effectiveness of different mesh sizes in the yellow croaker gillnet fishery. In particular, by comparing economic effects of mesh sizes, 50mm and 52mm, it aimed to provide the economic validity for increasing mesh sizes. Analytical results showed that the fishing revenue was higher in the vessels using a mesh size over 52mm than that in the vessels using a mesh size less than 50mm. In addition, the effect of fishing cost reduction was also larger in the vessels using a mesh size over 52mm than that in the vessels using a mesh size less than 50mm.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.115-121
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• 2016

PURPOSE: Many studies have reported the improvement of cognition through physical activity among subject with dementia. This study aimed to whether the current studies supports that physical activity intervention is efficacious on cognitive performance in subject with dementia. METHODS: Two independent reviewers searched National assembly library, RISS, KISS (2005-2015) using the concepts of dementia, exercise, and physical activity. We included randomized controlled trials that examined the efficacy of physical activity in subject with dementia. A meta-analysis was performed to estimate the effect sizes cognition with CMA (Comprehensive Meta-Analysis, version 2.2.064) soft-ware program. Nine randomized controlled trials were included, providing data from 133 individuals and excluding those failing to criteria of this study. RESULTS: The meta-analysis showed that physical activity intervention had a rather small effect sizes of 0.36 (95% confidence interval 0.14-0.59) on cognition performance in subject with dementia. Outcome measurement were MMSE-K (Mini-mental state examination Korean version) and LOCTA (Loewenstein Occupational Therapy Cognitive Assessment). We found heterogeneous among studies and there was difference between the studies (Q = 19.63, d(f)=12, $I^2= 38.88$). CONCLUSION: The present analysis suggests that physical activity interventions have the low effect sizes on cognition performance in subject with dementia Further studies will be required to develop the various programs for improving the cognitive performance in subject with dementia.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.1
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• pp.30-40
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• 2011

In recent years, driver information systems (DIS's) became popular and the use of DIS's increased significantly. A majority of DIS's provides touch-screen interfaces because of intuitiveness of the interaction and the flexibility of interface design. In many cases, touch-screen interfaces are mainly manipulated by fingers. In this case, investigating the effect of touch-key sizes on usability is known to be one of the most important research issues, and lots of studies address the effect of touch-key size for mobile devices or kiosks. However, there is few study on DIS's. The importance of touch-key size study for DIS's should be emphasized because it is closely related to safety issues besides usability issues. In this study, we investigated the effect of touch-key sizes of DIS's while simulated driving (0, 50, and 100km/h) considering driving safety (lateral deviation, velocity deviation, total glance time, mean glance time, total time between glances, mean number of glances) and usability of DIS's (task completion time, error rate, subjective preference, NASA TLX) simultaneously. As a result, both of driving safety and usability of DIS's increased as driving speed decreased and touch-key size increased. However, there were no significant differences when touch-key size is larger than a certain level (in this study : 17.5mm).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.1013-1018
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• 2014

Magnetic Abrasive Polishing (MAP) process is a nontraditional method for polishing the surface of workpiece by using the flexibility of tool. At present, a mixture of polishing abrasives and ferrous particles is used as the tool in the MAP process. Previously, an experiment was conducted with different sizes of polishing abrasives with an aim to improve the polishing accuracy. However, the sizes of ferrous particles are also expected to have a dominant effect on the process, warranting a study on the effect of the size of ferrous iron particles. In this study, an experiment was conducted using three different sizes of ferrous particles. Iron powder of average diameters 8, 78 and $250{\mu}m$ was used as ferrous particles. The effect of each ferrous particle size was evaluated by comparing the improvements in surface roughness. The particle size of a ferrous iron was found to play a significant role in MAP and particles of $78{\mu}m$ facilitated the best improvement in surface roughness.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.247-258
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• 2020

The purpose of this study is to synthesize and specifically analyze the effects of elementary SW-STEAM Education on learning outcomes by using meta-analysis. 29 papers are selected and total of 60 effect sizes are deduced. Total effect size is a medium effect of .35, which reveals significant effect on the cognitive and affective domains, and 8 moderator variables explain the difference in total effect sizes as well. The results show that SW-STEAM education is effective for elementary students' learning outcomes. Practical implication for design and implementation are addressed.

• Child Health Nursing Research
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• v.28 no.1
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• pp.23-40
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• 2022

Purpose: This systematic review and meta-analysis investigated the effects of parenting education programs (PEPs) for refugee and migrant parents. Methods: A systematic review was conducted according to PRISMA guidelines. Relevant studies published from 2000 to 2020 were identified through a systematic search of six electronic databases (PubMed, Embase, Cochrane Library, CINAHL, RISS, KMBASE). A meta-analysis of the studies was then undertaken. Results: Of the 14,996 published works identified, 23 studies satisfied the inclusion criteria, and 19 studies were analyzed to estimate the effect sizes (standardized mean differences) of the PEPs using random-effect models. PEPs were effective for parenting efficacy (effect size [ES]=1.40; 95% confidence interval [CI]: 1.14-1.66), positive parenting behaviors (ES=0.51; 95% CI: 0.30-0.73), parent-child relationships (ES=0.38; 95% CI: 0.22-0.53), and parenting stress (ES=0.64; 95% CI: 0.50-0.79). There were statistically significant differences in the effect sizes of PEPs that included mothers only (ES=0.93), included children under 7 years of age(ES=0.91), did not include child participation (0.77), continued for 19 or more sessions (ES=0.80), and were analyzed in quasi-experimental studies (ES=0.86). The overall effect of publication bias was robust. Conclusion: PEPs were found to be effective at improving parenting efficacy, positive parenting behaviors, parent-child relationships, and parenting stress.

• Progress in Medical Physics
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• v.6 no.2
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• pp.13-19
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• 1995

The behavior of the correction factor associated with the collimator opening(head-scatter factor) were investigated for the 6MV x-ray beams of medical linear accelerator. The primary photon fluence was measured in air quasi-small fied size. Consideration in this study was given to the effect of head scatter factor with quasi-small fied size, the upper and lower collimator jaw scatter collection factors of quasi-small field (4-10cm) were measured with ion chamber. In general, the wedge factors which are used clinical practics are ignored of dependency on field sizes and depth. In wedge factors for each wedge filter were measured at various depth by using 6MV X-ray. In this present we inverstigated systematically the depth and field sizes dependency to determine the absorbed dose more accurately. Head scatter(upper-lower collimator jaw)appears to be (1) a small effect, less than 5％ over the range of clinical field sizes (2) generated primarily at the flattening filter and therefored influenced most by the upper collimator setting.

• Journal of Powder Materials
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• v.20 no.5
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• pp.359-365
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• 2013

In this study, we fabricated $Nd_2Fe_{14}B$ hard magnetic powders with various sizes via spray drying combined with reduction-diffusion process. Spray drying is widely used to produce nearly spherical particles that are relatively homogeneous. Thus, the precursor particles were prepared by spray drying using the aqueous solution containing Nd salts, Fe salts and boric acid with the target stoichiometric composition of $Nd_2Fe_{14}B$. The mean particle sizes of the spray-dried powders are in the range from one to seven micrometer, which are adjusted by controlling the concentrations of precursor solutions. After debinding the as-prepared precursor particles, ball milling was also conducted to control the particle sizes of Nd-Fe-B oxide powders. The resulting particles with different sizes were subjected to subsequent treatments including hydrogen reduction, Ca reduction and washing for CaO removal. The size effect of Nd-Fe-B oxide particles on the formation of $Nd_2Fe_{14}B$ phase and magnetic properties was investigated.