• Research in Vestibular Science
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• 제17권4호
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• pp.152-159
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• 2018

Objectives: The Korean Dizziness Handicap Inventory (KDHI), which includes 25 patient-reported items, has been used to assess self-reported dizziness in Korean patients with Parkinson disease (PD). Nevertheless, few studies have examined the KDHI based on item-response theory within this population. The aim of our study was to address the feasibility and clinimetric properties of the KDHI instrument using polytomous Rasch measurement analysis. Methods: The unidimensionality, scale targeting, separation reliability, item difficulty (severity), and response category utility of the KDHI were statistically assessed based on the Andrich rating scale model. The utilities of the orderedresponse categories of the 3-point Likert scale were analyzed with reference to the probability curves of the response categories. The separation reliability of the KDHI was assessed based on person separation reliability (PSR), which is used to measure the capacity to discriminate among groups of patients with different levels of balance deficits. Results: Principal component analyses of residuals revealed that the KDHI had unidimensionality. The KHDI had satisfactory PSR and there were no disordered thresholds in the 3-point rating scale. However, the KDHI showed several issues for inappropriate scale targeting and misfit items (items 1 and 2) for Rasch model. Conclusions: The KDHI provide unidimensional measures of imbalance symptoms in patients with PD with adequate separation reliability. There was no statistical evidence of disorder in polytomous rating scales. The Rasch analysis results suggest that the KDHI is a reliable scale for measuring the imbalance symptoms in PD patients, and identified parts for possible amendments in order to further improve the linear metric scale.

• 한국터널지하공간학회 논문집
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• 제7권4호
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• pp.285-294
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• 2005

본 연구에서는 저토피 구간에서 기존터널 하부에 새로운 터널이 경사로 교차하여 신설할 때 하부 터널굴착으로 인하여 발생하는 교차부 주변지반과 상부터널의 거동을 분석하였다. 4.0m (폭), 3.8m (높이), 4.1m (길이) 크기의 콘크리트로 제작된 대형토조에서 모래를 이용하여 상대밀도기 일정한 모형지반을 3.4m높이로 조성하였고, 상하터널의 교차 각도가 $56^{\circ}$인 경우에 대하여 대형모형실험을 실시하였다. 또한, 모형실험과 동일한 조건으로 수치해석을 실시하여 실험결과와 연관하여 분석하였다. 연구결과 교차부 주변지반은 하부터널 종방향의 응력 전이로 인하여 교차 전과 교차 후에 응력과 지반변위의 차이가 발생하였다. 모형실험 결과로부터 교차 전 후의 하부터널굴착에 따른 종방향 응력전이가 상부터널에 의하여 차단됨을 알 수 있었다.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.102-111
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• 2010

This study was conducted to investigate the optimal conditions of collagen extraction from scales of yellowfin tuna (Thunnus albacares) using surface response methodology. Four independent variables of NaOH concentration and pretreatment fime in alkali pretreatment and enzyme concentration and treatment time in enzyme hydrolysis were used to predict a model equation for the collagen yield. The determinant coefficient ($R^2$) for the equation was 0.906. The values of the independent variables for the maximum yield were 0.32 N NaOH, 16.38 h alkali pretreatment time, 0.18% enzyme concentration, and 31.02 h enzyme treatment time. In the physicochemical properties of tuna scale collagen, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of tuna scale collagen showed the same migration distances as that of calf skin collagen. The amide A, I, II, and III regions of tuna scale collagen in Fourier transform infrared measurements were shown in the peaks of 3,414 $cm^{-1}$, 1,645 $cm^{-1}$, 1,553 $cm^{-1}$, and 1,247 $cm^{-1}$, respectively. The amount of imino acids in tuna scale collagen was 18.97% and the collagen denaturation temperature was $33^{\circ}C$. The collagen solubility as a function of NaCl concentration decreased to 4% NaCl (w/v) and the collagen solubility as a function of pH was high at pH 2-4 and sharply decreased from pH 4 to pH 7. Viscosity of the collagen solution decreased continuously until $30^{\circ}C$ and this decreasing rate slowed in the temperature range of $35-50^{\circ}C$.

• 한국학교수학회논문집
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• 제24권1호
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• pp.1-18
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• 2021

본 연구의 목적은 수학 교수 효능감 측정 도구(MTEBI)의 심리측정적 특성을 탐색하고 한국 초등 교사들에게 사용할 수 있게 측정 도구를 수정하는 것이다. 문헌 연구를 바탕으로 MTEBI 중 개인 효능감 요인만을 분석하였다. 299명의 초등 교사들의 설문자료를 Rasch 모형을 이용하여 일차원성 가정, 응답범주 적절성, 문항 난이도 적절성, 분리지수와 신뢰도 측면에서 분석하였다. 분석 결과 5점 범주로 된 13개 문항은 심리측정적 측면에서 몇 가지 문제가 있는 것으로 나타났다. 따라서, 후속 분석에서 5점 범주 대신 4점 범주로 수정하였으며 5개의 문항을 삭제한 후 8문항을 사용해 심리측정적 특성을 재분석하였다. 그 결과, 수정된 측정 도구는 초등 교사들의 수학 교수에 대한 개인효능감을 타당성 있게 측정하는 것으로 나타났다. 본 연구의 제한점과 제언을 추가 논의하였다.

• Nuclear Engineering and Technology
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• 제40권1호
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• pp.77-86
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• 2008

This paper describes the nonlinear analyses of a 1:4 scale model of a prestressed concrete containment vessel (PCCV) using an axisymmetric model and a three-dimensional model. These two models are refined by comparison of the analysis results and with testing results. This paper is especially focused on the analysis of behavior under pressure and the temperature effects revealed using an axisymmetric model. The temperature-dependent degradation properties of concrete and steel are considered. Both geometric and material nonlinearities, including thermal effects, are also addressed in the analyses. The Menetrey and Willam (1995) concrete constitutive model with non-associated flow potential is adopted for this study. This study includes the results of the predicted thermal and mechanical behaviors of the PCCV subject to high temperature loading and internal pressure at the same time. To find the effect of high temperature accident conditions on the ultimate capacity of the liner plate, reinforcement, prestressing tendon and concrete, two kinds of analyses are performed: one for pressure only and the other for pressure with temperature. The results from the test on pressurization, analysis for pressure only, and analyses considering pressure with temperatures are compared with one another. The analysis results show that the temperature directly affects the behavior of the liner plate, but has little impact on the ultimate pressure capacity of the PCCV.

• 한국측량학회지
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• 제17권3호
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• pp.283-292
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• 1999

본 논문에서는 대축척 항공 사진(1/5,000)을 촬영할 때 수신한 GPS 자료를 처리하여 결정한 항공 사진 카메라의 투영중심 위치를 이용한 항공삼각측량에 대해서 연구하였다. 항공삼각측량에 적용 가능성을 검토하기 위해 GPS자료를 처리하여 모델 조정법으로 결정한 투영중심의 위치와 비교하여 정확도 및 오차를 분석하였다. 또한, GPS 자료로 결정한 투영중심의 위치를 광속 조정법에 적용하였다. 기준국으로부터 30 km이내인 경우 L1 반송파 자료를 이용하여 결정한 투영중심 위치의 정확도는 일정하고, 4개의 기준점으로 평면(XY) 정확도(RMS)는 13 cm, 높이(Z) 정확도(RMS)는 15 cm로 수치지도 제작에 필요한 정확도를 얻을 수 있었다. 따라서, GPS를 항공삼각측량에 이용함으로써 경제적인 지도 제작 방안을 제시하였다.

• 산업경영시스템학회지
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• 제41권4호
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• pp.1-8
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• 2018

Whole body fatigue detection is an important phenomenon and the factors contributing to whole body fatigue can be controlled if a mathematical model is available for its assessment. This research study aims at developing a model that categorizes whole body exertion into fatigued and non-fatigued states based on physiological and perceived variables. For this purpose, logistic regression was used to categorize the fatigued and non-fatigued subject as dichotomous variable. Normalized mean power frequency of eight muscles from 25 subjects was taken as physiological variable along with the heart rate while Borg scale ratings were taken as perceived variables. The logit function was used to develop the logistic regression model. The coefficients of all the variables were found and significance level was checked. The detection accuracy of the model for fatigued and non-fatigues subjects was 83% and 95% respectively. It was observed that the mean power frequency of anterior deltoid and the Borg scale ratings of upper and lower extremities were significant in predicting the whole body fatigued when evaluated dichotomously (p < 0.05). The findings can help in better understanding of the importance of combined physiological and perceived exertion in designing the rest breaks for workers involved in squat lifting tasks in industrial as well as health sectors.

• 농촌지도와개발
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• 제23권1호
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• pp.15-25
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• 2016

In this study, we examined the awareness of consumers purchasing Punica granatum by conducting a survey on consumption of Punica granatum for the consumer panel of the Rural Development Administration (RDA) and derived the purchasing characteristics from the actual purchase date analyzed in a Linear regression model and Tobit model. Most consumers had been purchasing Punica granatum for health and beauty, and the proportion of that consumers were willing to repurchase Punica granatum was 93.1%. The result of examining the biggest considerations in 5 point scale when choosing a Punica granatum was in the order of freshness (4.37)> price (4.15)> safety (4.13)> size(3.86)> brand (3.27)> discount event (2.76). When we compared the results between a linear regression model and tobit model, the signs of all variables are consistent with each other. However, it was estimated that all absolute values of the coefficient values in the results of the tobit model analysis were larger than the values in the linear regression model, except for the "favorite purchasing place" of a weekday traditional markets. Punica granatum is known as a good fruit for postmenopausal women and it seems that the higher age is, the more purchase there will be. The more income a housewife had, the greater purchase there was. In the case of the purchase amount, a selecting for a eating pleasure was bigger than a selecting for a need of health. Therefore, it is necessary to develop Punica granatum with a taste in consumer preferences.

• 대한간호학회지
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• 제50권4호
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• pp.611-620
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• 2020

Purpose: The aim of this study was to evaluate the reliability and validity of the Korean version of the Wong and Law Emotional Intelligence Scale (K-WLEIS). Methods: Data were collected from 360 nursing students using a self reported questionnaire. Exploratory and confirmatory factor analysis were used to test construct validity. Convergence validity was identified by correlation with communication competency. Item convergent and discriminant validity were also analyzed. Reliability was evaluated internal consistency and test-retest reliability. Results: The results of exploratory factor analysis showed that the eigen values ranged from 1.34 to 5.86 and 73.2% of the total explained variance. Confirmatory factor analysis showed adequate model fit indices (χ²/df 1.89, RMSEA .07, GFI .89, CFI .95, and TLI .93) and standardized factor loadings (.48 to .87). The average extracted variances (.71 to .79) and composite reliability (.80 to .87) validated convergence and discriminant validity of the items. Test-retest reliability of intra-class correlation coefficient was .90 and the Cronbach's alpha coefficient was .88. Conclusion: The K-WLEIS is an appropriate scale for measuring the emotional intelligence of Korean nursing students. Therefore, it is expected that the K-WLEIS will be used for nursing education programs to improve nursing students' emotional intelligence.

• Human Ecology Research
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• 제59권3호
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• pp.387-400
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• 2021

This study examined the structural relationship between children's academic stress, grit, executive function difficulty, and media device addiction. Data on 1,132 children and their mothers from the 11^th (2018)Panel Study on Korean Children were used for the study. Data were collected by Academic Stress Scale, Grit Scale-Children, Child-Adolescent Self-reported Executive Function Difficulty Screening Questionnaire, and K-Internet Addiction Scale. Data were analyzed using SPSS 25.0 and AMOS 23.0 program with Pearson correlation, structural equation model and bootstrapping. The main results were as follows. 1) Children's academic stress had a negative influence on their grit. 2) Children's grit had a negative influence on their executive function difficulty and media device addiction. 3) Children's executive function difficulty had a positive influence on their media device addiction. 4) The relationship between children's academic stress and media device addiction was mediated by their grit and executive function difficulty. This study is significant in the sense that it found protective factors and risk factors for children's addiction to media devices. We suggest that children's grit be improved, and their academic stress and executive function difficulty be reduced to prevent and mediate children's media device addiction.