• Wind and Structures
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• v.6 no.6
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• pp.419-436
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• 2003

Large-eddy simulations of the flow around a circular cylinder at a Reynolds number, based on cylinder diameter and free-stream velocity, $Re_D=2{\times}10^4$ are presented. Three different dynamic subgrid-scale models are used, viz. the dynamic eddy-viscosity model and two different mixed two-parameter models. The sensitivity to grid refinement in the spanwise and radial directions is systematically investigated. For the highest resolution considered, the effects of subgrid-scale modeling are also discussed in detail. In particular, it is shown that SGS modeling has a significant influence on the low-frequency modulations of the aerodynamics loads, which are related to significant changes in the near wake structure.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.88-95
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• 2008

With society focusing more and more on environmental issues, the recycling of materials of all types has become an important concern. In this paper, optimization method is developed for reducing cost and improving quality in mill scale recycling. An experimental investigation into the process parameter effects is presented to determine the optimum configuration of parameters for performance, quality and cost. Taguchi's optimization approach was used to obtain the optimal parameters. The significant parameters were identified and their effects on mill scale recycling were studied. As a results, a confirmation experiment with the optimal levels of process parameters was carried out in order to demonstrate the effectiveness of the Taguchi method.

• Advances in materials Research
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• v.8 no.4
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• pp.259-274
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• 2019

Flexoelectric effect has a major role on mechanical responses of piezoelectric materials when their dimensions become submicron. Applying differential quadrature (DQ) method, the present article studies dynamic characteristics of a small scale beam made of piezoelectric material considering flexoelectric effect. In order to capture scale-dependency of such piezoelectric beams, nonlocal elasticity theory is utilized and also surface effects are included for better structural modeling. Governing equations have been derived by utilizing Hamilton's rule with the assumption that the scale-dependent beam is subjected to thermal environment leading to uniform temperature variation across the thickness. Obtained results based on DQ method are in good agreement with previous data on pizo-flexoelectric beams. Finally, it would be indicated that dynamic response characteristics and vibration frequencies of the nano-size beam depends on the existence of flexoelectric influence and the magnitude of scale factors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.2
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• pp.131-135
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• 2011

We have been studied the effects of oxidant on the properties of Sr-ferrite magnets using mill scale for motor. The small-added (0.5 wt%) $NaNO_3$ oxidant improved significantly the degree of oxidation and the grindability of mill scale, and then highly enhanced the magnetic properties of anisotropic Sr-ferrite sintered magnets; such as the remanent flux density from 3.55 to 3.80 kG, the intrinsic coercivity from 2.75 to 3.22 kOe, and the maximum energy product from 2.90 to 3.45 MGOe.

• Journal of Korean Public Health Nursing
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• v.25 no.2
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• pp.187-196
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• 2011

Purpose: The study evaluated the effects of a fall prevention program in a Korean rural area. Methods: A single pretest-posttest design group was studied. Thirty nine residents in the same rural area participated in a program comprised of education and exercise. The 5-week fall prevention program was performed for 60 minutes, once a week. Results: Fall Efficacy Scale (FES) score and Activities-specific of Balance Confidence Scale (ABC) score were significantly increased after the program, but the pre-and posttest FES and ABS scores were not significantly different between the fall experience group and non-fall experience group. Conclusion: The fall prevention program can improve rural residents' FES and ABS, and is recommended as a fall prevention intervention.

• Journal of the Korean Home Economics Association
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• v.41 no.3
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• pp.147-164
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• 2003

The purpose of this study was to investigate the effects of the family of origin variables on marital conflict. Seventy five married couples living together for less than 10 years were chosen from Seoul and Suwon cities. These subjects completed Korean Version of Family Adaptability and Cohesion Evaluation Scale Ⅱ, Individual Separation Scale, Family Rules Scale, Korea Certificated Egogram, and Marital Conflict Scale. The data were analyzed using descriptive statistics, paired-t test, and hierarchical regressions. The results were as follows: First, husbands and wives were different from each other in triangulation, family rules from family of origin and marital conflict. While husbands felt more strongly about their family rules than wives, wives perceived triangulation, and marital conflict higher than husbands. Second, husbands' controlling ego state, individuation, and family rules explained sixteen percents of husbands' marital conflict. Statistically speaking husbands' controlling ego state positively influenced on husbands' marital conflict. However, both of husbands' and wives' controlling ego states explained twelve percents of wives' marital conflict, and husbands' controlling ego state was statistically significant.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.62-69
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• 2006

Objective : This study was conducted to investigate as to whether obesity have any effects on conscious sedation outcomes. Methods : Forty children (mean age 30.5 months, mean height and weight were 91.3cm, 14.3kg respectively) were sedated with chloral hydrate (60 mg/kg) and hydroxyzine (25mg). The relative obesity rate of the patients was obtained by the proportion of height to weight and the tonsil size of the patients was classified by Brodsky's scale. The overall sedation outcomes were evaluated by Houpt's scale. The pulse and respiratory rates during sedation were also evaluated. Results: The obesity of the patients had no statistically significant effects on movement, crying during sedation. However, an increase in obesity had negative effects on the overall conscious sedation outcomes. Conclusion: This investigation demonstrated that increased obesity may cause detrimental effects on pediatric conscious sedation outcomes.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.43.3-44
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• 2015

We analyze the clustering of large scale structure in the Universe in a model independent method, accounting for anisotropic effects along and transverse to the line of sight. A large sample of 690,000 galaxies from The Baryon Oscillation Spectroscopy Survey Data Release 11 are used to determine the Hubble expansion H, angular distance D_A, and growth rate GT at an effective redshift of z=0.57. After careful bias and convergence studies of the effects from small scale clustering, we find that cutting transverse separations below 40 Mpc/h delivers robust results while smaller scale data leads to a bias due to unmodelled nonlinear and velocity effects. The converged results are in agreement with concordance LCDM cosmology, general relativity, and minimal neutrino mass, all within the $68{\backslash}%$ confidence level. We also present results separately for the northern and southern hemisphere sky, finding a slight tension in the growth rate -- potentially a signature of anisotropic stress, or just covariance with small scale velocities -- but within $68{\backslash}%$ CL.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.33-42
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• 2020

PURPOSE: This study examined the effects of a whole body vibration-exercise program on the muscle strength, balance, and falling efficacy of super-aged women. METHODS: Thirty participants, who are over 75 years of age, were recruited. They were assigned randomly to an experimental group (n=15), which received whole body vibration exercise, and a control group (n=15), which received an exercise program that did not include vibration. The interventions lasted for four weeks, three times a day, and 25 minutes per session. To compare the effects of the intervention, a 30-second chair stand test (CST), Korean version of Berg balance scale (K-BBS), functional reach test (FRT), timed up and go test (TUG), and Korean version of the falls efficacy scale (K-FES) was used. RESULTS: The experimental group showed a significant increase (p.<05) before and after the intervention in the chair stand test (CST), Korean version of the Berg balance scale (K-BBS), functional reach test (FRT), timed up-and-go (TUG), and Korean version of the fall efficacy scale (K-FES). Compared to the control group, the experiment group showed a more significant increase (p.<05) in the CST, K-BBS, and FRT. CONCLUSION: A whole body vibration exercise program could be suggested as an effective intervention method for muscle and balance strengthening for super-aged women.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.7
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• pp.575-580
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• 2007

During the conceptual design phase of a canard type high maneuverable aircraft, the low speed small scale wind tunnel test was conducted to investigate the high angle-of-attack static stability of the aircraft. In this study, 1/50th scale generic canard-body-wing model was used for the small scale wind tunnel test. For the analysis of static stability including high angle-of-attack nonlinear characteristics, the vertical tail effects were studied due to canard deflections. In addition, the nose chine effects were studied at high angle-of-attack. Based on the results obtained from the experimental study, the configuration change effects for canard type aircraft on high angle-of-attack static stability have been able to analyze.