• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1705-1708
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• 2003

The purpose of this study is to investigate the manufacturing technique on the U type Draw-Bending of inner grooved tube. This bending process make the U shape tube by Hair Pin Bending machine. The U type tube requires the quality of product that satisfy sufficient conditions for a heat exchanger. The mandrel components act the important roles that prevent wrinkles and keep the shape of cross section of bended tube at bending process. We performed the FEM simulation using LS-DYNA software and the bending test of inner groove tube and then, compared bending simulation with bending test results about mandrel ball diameter, mandrel position and optimal clearance between mandrel and tube.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.66-72
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• 2007

In this study, we would like to report the analysis of COMS(Communication, Ocean & Meterological Satellite) MI2U(Meteo-Imager Interface Unit) ORB (On Board Reconfiguration) verification test. MI2U is one of equipment integrated on COMS and in charge of TM/TC function and Power Supply function of MI(Meteo-Imager). COMS, an geo-stationary satellite, is a multi-functional satellite accommodation two observation payloads and one communication payload.

• Tunnel and Underground Space
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• v.8 no.4
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• pp.261-274
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• 1998

The brief results of laboratory and field tests of yieldable steel arches are represented. The test supports were fabricated with three U-sectional beams which are 25.8 kg/m of Glocken profile. The structural analyses of semi-circular and arch supports were conducted to find out shape factor of U beam to be 1.35 and the location of 2nd plastic hinges. Load capacity of arch supports under crown loading were examined as a function of leg length. Yieldable characheristics of test supports were investigated with various bolting torque of connection part. Determination method of bolting torque were also studied. Finally, test supports were installed in-situ with torque of 21 kg .m, which showed a typical yielding procedure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.210-217
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• 1999

This paper reports the experimental results on heat transfer characteristics of R-22 and R-407C(HFC-32/125/134a 23/25/52 wt%) condensing inside horizontal smooth and finned tubes. The test condensers used In the study are double pipe heat exchangers of 7.5 mm ID, 9.5 mm OD smooth tube, and 60 finned micro-fin tube with 8.53 mm ID, 9.53 mm OD. Each of these tubes was 4 000 mm long tubes connected with an U-bend. These U type two-path test tubes are divided In 8 local test sections for the identification of the local condensing heat transfer characterisitcs and pressure drop, U-bend effects on condensing flows. Inlet quality is maintained 1.0, and refrigerant mass velocity is varied from 102.0 to $301.0kg/m^2{\cdot}s$. From the results, it was found that the pressure drop of the R-407C Increased, and heat transfer coefficient decreased compared to those of R-22. In comparison condensing heat transfer characteristics of micro-fm tube with those of smooth tube, increasing of condensing heat transfer coefficient was found outstanding compared to the increasing ratio of pressure drop. Furthermore, pressure drop In U-bend showed at most a 30 % compared to the total pressure drop in the test section.

• Journal of Society of Preventive Korean Medicine
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• v.21 no.1
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• pp.31-39
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• 2017

Objectives : This study was conducted to identify the effects of the program for preventing dementia on Korean medicine on the Knowledge of dementia, Preventive behavior, Depression and Hwa-Byung for elderly. Methods : A non-equivalent control group pretest-posttest design was used with 41 elderly who were assigned to the experimental and control group. Study outcomes were measured by structured questionnaires from August to November 2016. For data analysis, the Chi-square test, the Fisher's exact probability test, t-test, the Mann-Whitney U test, were performed using SPSS version 20.0. Results : There were significant differences in Knowledge of dementia(U=112.500, p <.010), Preventive behavior (U=124.000, p =<.024), and Hwa-Byung (U=129.000, p =<.034) between the two groups in pretest and posttest. Conclusions : The findings have confirmed that the program for preventing dementia on Korean medicine is effective to improve Knowledge of dementia, Preventive behavior, and Hwa-Byung of community elderly. It can be recommended as a public health program for the elderly in communities.

• Ocean and Polar Research
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• v.25 no.spc3
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• pp.353-360
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• 2003

Estimation of undrained shear strength $(S_u)$ of clayey soils from piezocone penetration test (CPTu), which has widely been known as one of very promising in situ test methods, requires piezocone factors. Empirical correlations are generally utilized to derive piezocone factors, but previous studies on the empirical piezocone factors are site-specific and in some cases need engineering characteristics, which should be obtained from additional laboratory tests. In this study, empirical cone factors were evaluated by comparing 6 CPTu results at Shihwa region in Korea with reference $S_u$ values obtained from field vane test (FVT). From previous CPTu results of other regions in Korea as well as the results herein, the correlations between piezocone factor, $N_{kT}$ and CPTu results were investigated and three simplified evaluation methods of $S_u$ using only CPTu results were presented. The $S_u$ values estimated by $(q_T-{\sigma}_v)/{\sigma}'_v$ method shows better matches with those obtained from laboratory tests for marine clays at Shihwa region.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.125-131
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• 2003

The U-draw bending operation is known as a representative test method for springback evaluation of sheet metals since the sheet in U-draw bending operation undergoes stretching, bending and unbending deformations occurred at read stamping process. In this study, a simplified approach was proposed for predicting springback and side-wall curls in U-draw bending operations, using moment-curvature relationships derived for sheets undergoing stretching, bending and unbending deformation.

• Communications for Statistical Applications and Methods
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• v.22 no.1
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• pp.81-93
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• 2015

Validity of the stationary bootstrap of Politis and Romano (1994) is proved for U-statistics under strong mixing. Weak and strong consistencies are established for the stationary bootstrap of U-statistics. The theory is applied to a symmetry test which is a U-statistic regarding a kernel density estimator. The theory enables the bootstrap confidence intervals of the means of the U-statistics. A Monte-Carlo experiment for bootstrap confidence intervals confirms the asymptotic theory.

• Korean Journal of Occupational Health Nursing
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• v.22 no.2
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• pp.112-120
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• 2013

Purpose: The purpose of this study was to identify the influence of interpersonal attitude (I+, I-, U+, U-) on communication competence in care workers for frail elderly. Methods: This study was a cross-sectional survey. The data were collected from 153 care workers for frail elderly using a structured questionnaire. The data were analyzed using multiple regression with the SPSS/WIN 20.0 program. Results: The interpersonal attitude style of subjects was I+U+, and the score of communication competence was 3.53. There were significant differences in interpersonal attitude (I+, I-), and communication competence depending on age, education level, experience of personality type test (yes). Factors influencing on communication competence in care workers were interpersonal attitude (I+, I-, U+) and experience of personality type test with $R^2$ value of 48.5% (F=23.47 p<.001). The most influencing factor was I+ (${\beta}$=.36), followed by I- (${\beta}$=-.22), U+ (${\beta}$=.20), and experience of personality type test (yes) (${\beta}$=.16). Conclusion: It is needed to maintain the interpersonal attitude style (I+U+) of care workers. Continuing education program is needed for increasing communication competence especially for those fifties and over, and experienced care workers. Giving an opportunity for personality test is helpful to increase communication competence in care workers.

• Annals of Pediatric Endocrinology and Metabolism
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• v.23 no.4
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• pp.215-219
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• 2018

Purpose: We investigated the effect of overweight on luteinizing hormone (LH) levels after a gonadorelin stimulation test in Korean girls with idiopathic central precocious puberty (CPP). Methods: Medical records of 234 girls diagnosed with idiopathic CPP were reviewed retrospectively. CPP was diagnosed when the peak LH levels after gonadorelin stimulation was >5.0 U/L. The enrolled girls had a peak LH level >5.0 U/L after a gonadorelin stimulation test. Selected girls were classified as normoweight (body mass index [BMI] below the 85th percentile with respect to age) and overweight (BMI greater than the 85th percentile with respect to age). Results: The peak LH ($8.95{\pm}2.85U/L$ vs. $11.97{\pm}8.42U/L$, P<0.01) and peak folliclestimulating hormone ($9.60{\pm}2.91U/L$ vs. $11.17{\pm}7.77U/L$, P=0.04) after gonadorelin stimulation were lower in overweight girls with idiopathic CPP than in normoweight girls with idiopathic CPP. Being overweight was negatively associated with peak LH levels after gonadorelin stimulation test (odds ratio, 0.89; 95 % confidence interval, 0.81-0.98, P=0.02). Conclusion: In girls with idiopathic CPP, being overweight led to a lower LH peak after gonadorelin stimulation. Further research is needed to better understand the role of overweight on gonadotropin secretion in precocious puberty.