• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.371-383
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• 2012

Shaping the root canal system to maintain original canal curvature is essential to clinical success in endodontic treatment. Opposed to most root canals that are curved, endodontic instruments are made from straight metal blanks. They have a tendency of straightening the root canal during preparation and frequently result in procedural errors. A new treatment method to maintain original canal curvature during shaping has been introduced for preventing procedural errors. The aim of this study was to compare the ability of instruments to maintain original canal curvature of continuous rotary system and single file system. Thirty ISO 15, 0.02 taper, Endo Training Blocks(Dentsplay Maillefer) were used. Specimens were assigned to 1 of 3 groups for shaping: specimens in group 1 were shaped with ProFile #20/.06 at the WL. Specimens in group 2 were shaped with Mtwo #35/.04 at the WL. Specimens in group 3 were shaped with WaveOne Primary reciprocating files at the WL after the glide path was achieved with PathFile. Pre- and postinstrumentation digital images were superimposed and processed with Matlab r2010b(The MathWorks Inc, Natick, MA) software to analyze the curvature-radius ratio(CRr), representing canal curvature modification. Data for comparison on the ability of instruments to maintain original canal curvature depending on each Ni-Ti file were analyzed with 1-way ANOVA(P<.05). Data for comparison on the ability of instruments to maintain original canal curvature depending on each Ni-Ti file system were analyzed with independent t-test(P<.05). A statistically significant difference(P<0.05) was noted on each Ni-Ti file. ProFile and WaveOne instrumentations maintained the original canal curvature significantly better(P<0.05) than Mtwo file. There were no significant difference(P>0.05) between continuous rotary system and single file system. Under the conditions of this study, ProFile and WaveOne instruments maintained the original curvature significantly better than Mtwo file and were less modification of the canal curvature compared. There was no significant difference between continuous rotary system and single file system in shaping of simulated canals. As clinical practitioners, it may be advantages to use hybrid approach when root canal shapes depending on the design and usage of Ni-Ti files.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.735-744
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• 2012

In order to quantify the flow distribution characteristics of APR+ reactor, a test was performed on a test facility, ACOP ($\underline{A}$PR+ $\underline{C}$ore Flow & $\underline{P}$ressure Test Facility), having a length scale of 1/5 referring to the prototype plant. The major parameters are core inlet flow and outlet pressure distribution and sectional pressure drops along the major flow path inside reactor vessel. To preserve the flow characteristics of prototype plant, the test facility was designed based on a preservation of major flow path geometry. An Euler number is considered as primary dimensionless parameter, which is conserved with a 1/40.9 of Reynolds number scaling ratio. ACOP simplifies each fuel assembly into a hydraulic simulator having the same axial flow resistance and lateral cross flow characteristics. In order to supply boundary condition to estimate thermal margins of the reactor, the distribution of inlet core flow and core exit pressure were measured in each of 257 fuel assembly simulators. In total, 584 points of static pressure and differential pressures were measured with a limited number of differential pressure transmitters by developing a sequential operation system of valves. In the current study, reactor flow characteristics under the balanced four-cold leg flow conditions at each of the cold legs were quantified, which is a part of the test matrix composing the APR+ flow distribution test program. The final identification of the reactor flow distribution was obtained by ensemble averaging 15 independent test data. The details of the design of the test facility, experiment, and data analysis are included in the current paper.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.475-482
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• 2015

Objective : The purpose of this study was to investigate mean plantar foot pressure, maximum plantar pressure and ground reaction force, and center migration path of pressure according to the type of trekking shoes for the development of shoes. Method : Subjects of the study averaged $22.10{\pm}2.05years$ of age. Their average height was $169.27{\pm}7.62cm$ and their average weight was $64.34{\pm}10.22kg$. The method of this study was administered measuring 50 steps, at once, 3 times at a speed of 4 km/h and using the data of 30 steps. Pedar-X system measured the mean foot pressure, maximum foot pressure, mean maximum force, and center migration path of pressure by subjects' position while walking. Statistical analysis was performed by SPSS 23.0 using a paired t-test. Results : Results of the study showed Nestfit trekking shoes lower foot pressure of both feet in mean foot pressure and maximum foot pressure. Nestfit trekking shoes showed high ground reaction force (p<.001) in the midfoot, and low mean ground reaction force in the rearfoot. The center migration path of pressure showed the Nestfit trekking shoes were more stable than flat insole trekking shoes. Conclusion : It can be concluded that wearing Nestfit trekking shoes spreads pressure efficiently and induces walking stability because Nestfit trekking shoes spread the pressure of the forefoot and rearfoot to the midfoot and the center migration path of pressure shows regularly.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1003-1012
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• 2007

In this study, we analyzed the release differences for some critical pollution compounds according to the surrounding conditions in order to predict water quality due to the sedimental releases and the release characteristics at different sedimental locations in Lake Leewon, in Tae-An area. COD, nitrogens and phosphates were analyzed using the standard methods for water quality, based on high chloride ion concentration(greater than 2,000 ppm). For COD, the release rate increased in the anoxic basin but almost the same in the oxic basin. For $NH_3$-N, the release rate decreased in the oxic basin as you go A through C point meanwhile, for $NO_3$-N and T-N, the tendency was reversed because of nitrification of them. In the anoxic basin, the release rates of $NH_3$-N and $NO_3$-N went up with A through C path. However, the release rate of T-N was found to decrease. Also, for $PO_4$-P and T-P, the release rates in the oxic basin were lowest at B point mainly because the phosphates were at less released in the highly $O_2$ concentrated environment. In the anoxic reactor, $PO_4$-P was released similarly regardless of the sampling points. In summary, the release rates in the oxic reactor were greater than those in the anoxic reactor for COD and $NO_3$-N. For the other components, the anoxic basin generated the higher release rates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.65-73
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• 2021

This study aimed to provide the basic data for the development of a simulation training program for new infectious diseases by analyzing the knowledge and educational needs of 119 paramedics regarding COVID-19 infection control. Data was obtained through a structured questionnaire survey of 186 paramedics from November 15th to 30th 2020. The study showed that 98 of the 119 paramedic subjects (52.7%) had not been educated regarding COVID-19. The knowledge level was 18.21±1.98 out of 25 points, with environmental control securing the lowest correct answers. The highest need for education was in the areas of prevention of transmission and spread, and employee safety control. The total average for educational needs was 3.81±.28 (4 point scale) with the highest educational need in the area of prevention of the spread and dispersion of the disease and employee safety management. There was a statistically significant difference in the knowledge of the general characteristics according to gender (t=-1.999, p=.047) and the educational demand was related to career (t=-1.999, p=.047) and, education levels (t=2.336, p=.021). Accordingly, it is necessary to plan a new infectious disease simulation education program that addresses the low-scoring areas and items with high educational needs which include the propagation path and spread prevention, environmental management, and employee safety management as per the findings of this study.

• Child Health Nursing Research
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• v.7 no.2
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• pp.179-190
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• 2001

The purposes of the study were to develop an instrument for family value and to identify the relationships of family value, family hardiness, and family adaptation by appling the family value scale to family with cancer children. The study was conducted in three phases. 1) A survey was conducted from July 20 to August 20, 1999 and 18 items of general family value scale was modified from the data of 153 fathers and 164 mothers. 2) In-depth interviews were made with 29 parents of cancer children from April 20, 1998 to May 20, 1999 to develop family value scale with cancer children, and 12 statements were developed. 3) The final survey was conducted from July 18, 2000 to August 30, 2000 and the data from 309 parents of children who are diagnosed as cancer, 18 or less years of age, and treated either hospitalized or at the outpatient clinics were analyzed to identify the relationships of the concepts. The data analysis utilized SAS 6.12 and LISREL 8 for descriptive statistics, correlation, and Regression for path analysis. The study findings are as follows. The psychometric testing of general family value scale was Cronbach's alpha = 0.78. The reliability of the family value scale with cancer children showed the reliability as Cronbach's alpha = 0.73. Demographic characteristics showing significant correlations were cancer children's age, period of illness, period after completing treatment, mother's age, mother's education level, monthly income, payment type, confidence with health professional, and severity of children's illness. The correlation coefficients among major variables showed that family stressor was positively related with family strains(r=0.33, p<.001), and negatively related with family hardiness(r=-0.21, p<.001). Family strains was negatively related with family hardiness(r= -0.41, p<.001) and family adaptation(r=-0.46, p<.001). Correlations of family hardiness was positive with family value with cancer children(r=-0.31, p<.001), and negative with general family value(r=-0.16, p<.01). Family hardiness was positively related with family adaptation(r=0.35, p<.001). The causal relationship between study variables showed that family strains predicts general family value(γ=0.12, t=2.02), family value with cancer children predicts family hardiness(γ=0.31, t=6.30), family strains predicts family hardiness(γ=-0.40, t=-7.70), family value with cancer children predicts family adaptation(γ=-0.23, t=-4.11), and family hardiness predicts family adaptation(γ=0.43, t=7.78).

• Journal of Korean Academy of Nursing Administration
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• v.19 no.2
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• pp.265-272
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• 2013

Purpose: This study was done to identify the effects and relationships of humor, job satisfaction, job stress and intent to turnover for nurses and suggest a theoretical structural path diagram among the variables. Methods: Data were collected at 6 hospitals located in Seoul, and Gyeonggi Province, from June to September, 2010. Participants were 275 nurses. Data were analyzed using Amos 19.0 for Structural Equation Modeling. Results: Humor had significant effects on job satisfaction (${\beta}$=.15, t=2.29, p=.022) and indirect effects on the intent to turnover in this model ($X^2$=44.18, df=23, RMSEA=0.05, TLI=0.97). But humor did not affect job stress unlike results of previous studies (t=-.02, p=.771). Conclusion: Humor may not affect job stress under the very stressful conditions of the health care environment. The model showed the effect of humor contributed to increases in job satisfaction but did not decrease job stress. Higher levels of job satisfaction could decrease the intent to turnover. Consequently, humor would be helpful in increasing job satisfaction to diminish nurse turnover. Further studies are suggested to investigate causal relationships among humor, burnout, and other emotional and organizational variables.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.392-395
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• 1995

This paper presents a time efficient method for determining a sequence of locations of a mobile manipulator that facilitates tracking of continuous path in cluttered environment. Given the task trajectory in the form of octree data structure, the algorithm performs characterization of task space and subsequent multistage optimization process to determine task feasible locations of the robot. Firstly, the collision free portion of the trajectory is determined and classified according to uniqueness domains of the inverse kinematics solutions. Then by implementing the extent of task feasible subspace into an optimization criteria, a multistage optimization problem is formulated to determines the task feasible locations of the mobile manipulator. The effectiveness of the proposed method is shown through a simulation study performed for a 3-d.o.f. manipulator with generic kinematic structure.

• 한국노년학
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• v.38 no.4
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• pp.891-903
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• 2018

This study investigated the relation between frailty, social support, and health-related quality of life to provide basic data to improve the health-related quality of life of old-old elderly who are a high risk group for frailty. For this descriptive study, one-on-one interviews with structured questionnaires were conducted for elderly aged 75 years or older at elderly welfare facilities in K county from March 01 to 31 in 2016, and a total of 211 elderly were interviewed. The collected data were analyzed by t-test, Pearson's correlation coefficient, and path analysis using SPSS/WIN and AMOS 18.0 program. For the differences between the age groups, those aged over 80 years had a significantly higher frailty (t=-2.51, p=.013) and a lower health-related quality of life than those aged below 80 years (t=3.29, p=.001); however, there was no significant difference in social support (t=1.28, p=.201). The correlation between frailty, social support and health-related quality of life showed that as frailty became higher, social support (r=-.21, p=.003) and health-related quality of life (r=-.65, p<.001) were significantly lower, and health-related quality of life was significantly higher with a higher social support (r=.18, p=.010). As a result of investigating the mediating effects of frailty between social support and health-related quality of life, social support had a significant direct effect on frailty (${\beta}=-.21$, p=.016) and frailty had a significant direct effect on health-related quality of life (${\beta}=-.06$, p=.004); however, social support had no significant direct effect on health-related quality of life (${\beta}=.00$, p=.562). Social support had a significant indirect effect on health-related quality of life and a mediating effect on frailty (${\beta}=.01$, p=.012); therefore, the full mediation effect of frailty between social support and health-related quality of life was verified. Social support prevents frailty, and improving frailty enhances health-related quality of life. Therefore, it is necessary to develop a multifactorial frailty prevention program that includes age-specific social support strategies to improve the health-related quality of life in old-old elderly.

• Journal of the Korean Home Economics Association
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• v.34 no.3
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• pp.245-257
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• 1996

The purpose of this study was to investigate the influences of children's perception of maternal acceptance-rejection and self-evaluation on learned helplessness. The Subjects were 371 fifth and sixth grade children. The helplessness scale, PAQ, PARQ were used. The data was analyzed by factor analysis, MANOVA, ANOVA and path analysis which was made through multiple regression analysis. The results were as follows: 1. The children's perceived maternal acceptance was significantly different depending on their parent's education level. In children's perceived parental rejection, there were gender differences. 2. In the children's self-evaluation, there were an interaction effect determined by the child's sex and the mother's education level, and a main effect of mother's education level. 3. Children's learned helplessness was significantly different depending on their mother's education level. 4. Children's perceived maternal acceptance(β=-0.36, p<.01) and rejection (β=0.17, p<.01) had a direct impact on their self-evaluation. Their self-evaluation(β=0.54, p<.01) and perceived maternal rejection(β=0.16, p<.01) had a direct impact on learned helplessness, but perceived maternal acceptance didn't have a direct impact on learned helplessness.