• 대한토목학회논문집
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• 제8권2호
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• pp.167-175
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• 1988

본 연구의 목적은 변동하중을 받는 구조부재의 피로거동을 해석하는 것이다. 이 연구의 해석과정은 다음과 같다. (1) 도로교의 실동응력파측정 및 통계적해석 (2) 등가의 일정진폭하중과, 통계적해석에 의해 모형화된 변동하중하(下)의 피로시험 (3) 등가응력개념의 RMC 모델에 의한 변동하중하(下)의 피로해석 등가응력개념에 의한 변동하중하(下)의 피로해석은 대부분의 구조용강재의 균열성장속도회귀지수가 $m{\fallingdotseq}3$이므로 이론적으로 RMC 모델이 합당하다. 변동하중하(下)의 피로시험해석결과 RMC 모델이 기존의 RMC 모델보다 변동하중에 의한 피로거동치(da/dN-${\Delta}K$, $N_f$)에 더 가까웠다. 또 변동하중하(下)에서 응력범위의 변화로 인한 interaction효과나 응력범위적용순서(sequence)효과 등은 피로수명에 거의 영향을 미치지 않으며, 응력범위변화속도가 클수록 피로균열성장속도가 빨라짐을 알 수 있었다.

• Restorative Dentistry and Endodontics
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• 제47권3호
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• pp.34.1-34.12
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• 2022

Objectives: This study aimed to evaluate the success rate of endodontic treatments performed by undergraduate students and the factors associated with the outcome. Materials and Methods: A follow-up of 3 to 8 years after root canal filling was carried out in 91 patients. At the follow-up visits, medical and dental history questionnaires were applied along with clinical and radiographic examinations. Data collected in the clinical exam included: the presence of pain, swelling, sinus tract, mobility, tenderness to palpation and percussion, periodontal probing profile, and type/quality of coronal restoration. Postoperative and follow-up radiographs were digitalized and analyzed by 2 trained and calibrated examiners to assess periapical healing. The treatment outcome was based on strict clinical and radiographic criteria and classified as success (absence of any clinical and radiographic sign of apical periodontitis) or failure (other combination). Logistic regression was used to investigate the impact of clinical and radiographic variables on endodontic treatment outcomes at a 5% significance level. Results: The success rate of endodontic treatments was 60.7%. The only risk factor significantly associated with failure was the presence of a periapical lesion on the postoperative radiograph (odds ratio, 3.35; 95% confidence interval, 1.17-9.54). Conclusions: The success rate of endodontic treatments performed by undergraduate students was low and was jeopardized by the presence of a periapical lesion on the postoperative radiograph.

• 서비스연구
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• 제13권1호
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• pp.176-185
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• 2023

본 연구는 산업현장 요양재해율 증가 및 중대재해처벌법 시행에 따라 산업재해 예방 대책의 필요성 차원에서 부각되고 있는 산업안전디자인의 도입시 경제적 성과를 측정하기 위한 모델을 개발하는 연구이다. 이를 위해서 이론 및 문헌연구 차원에서 산업안전관리와 산업안전디자인의 개념과 산업안전 분야에서의 경제적 성과 측정에 관한 연구를 수행하였다. 이론 및 문헌연구을 기반으로 사용자 의견 설문을 통하여 관련한 지표들의 초안에 대한 의견을 수렴하고, 전문가들을 대상으로 포커스그룹 인터뷰와 델파이기법을 수행하면서, 모델을 고도화하는 연구를 진행하였다. 객관성 확보를 위하여 회귀분석으로 산업안전디자인의 도입과 비용절감효과, 매출증대효과와의 인과관계를 검정하였다. 이와 같은 단계를 거쳐서, 최종적으로 1단계 재해손실비용 절감 효과 기반의 모델과 2단계 매출액 증대 효과 기반의 2가지 산업안전디자인의 경제적 성과측정 모델을 개발하였다. 실제 산업현장에 적용하기 위해서는 단순한 체크리스트를 넘어서는 산업안전디자인의 서비스 수준 계약 정도에 대한 표준으로써 제시될 수 있어야 한다.

• 대한한의학회지
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• 제35권1호
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• pp.88-98
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• 2014

Objectives: The purpose of this study is to investigate the relationship between bone age, chronological age, anthropometric parameters, and diagnosed pulse rate on child-adolescence's growth according to sex and the revelation of secondary sexual characteristics. Methods: Growth-concerned 44 children and adolescence (from 6 to 16 years) were analyzed in retrospective study. They visited Korean Medical Clinic in Suwon, Korea from January 2012 to October 2013. Individual bone age (BA), chronological age (CA), Risser sign, anthropometric parameters, and pulse rate were measured. The correlations of each variable were done by Pearson analysis, Spearman analysis and Regression analysis. Results: 1. The female group was shown to have stronger negative correlation between pulse rate and BA, CA than the male group. In gender analysis, the female group showed negative correlation between weight and pulse rate. 2. In a further analysis according to the revelation of secondary sexual characteristics, the group of child-adolescent without secondary sexual characteristics was shown to have stronger negative correlation between pulse rate and BA, CA than the group with secondary sexual characteristics. The height percentile and pulse rate were negative correlation in secondary sexual character being. 3. The Risser sign and pulse rate were not correlated in this study. Conclusions: These findings suggested that a regular and continual measurement of pulse rate is effective in estimating potential for growth in child-adolescent group.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.183-186
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• 2003

To evaluate the effect of air pollution on respiratory health in children, we conducted a longitudinal study in which children were asked to record their daily levels of peak expiratory flow rate using potable peak flow meter (mini-Wright) far 4 weeks. The relationship between daily PEFR and ambient air particle levels was analyzed using a mixed linear regression models including gender, age in you, weight, the presence of respiratory symptoms, and relative humidity as an extraneous variable. The daily mean concentrations of PM$\_$10/ and PM$\_$2.5/ over the study period were 64.9$\mu\textrm{g}$/㎥ and 46. l$\mu\textrm{g}$/㎥, respectively. The range of daily measured PEFR in this study was 170-481 l/min. Daily mean PEFR was regressed with the 24-hour. average PM$\_$10/ (or PM$\_$2.5/) levels, weather information such as air temperature and relative humidity, and individual characteristics including sex, weight, and respiratory symptoms. The analysis showed that the increase of air particle concentrations was negatively associated with the variability in PEFR. We estimated that the IQR increment of PM$\_$10/ or PM$\_$2.5/ were associated with 1.5 l/min (95% Confidence intervals -3.1, 0.1) and 0.8 l/min (95% Cl -1.8, 0.1) decline in PEFR. Even though this study shows negative findings on the relationship between respiratory function and air particles, it is worth noting that the findings must be interpreted cautiously because exposure measurement based on monitoring of ambient air likely results in misclassification of true exposure levels and this is the first Korean study that PM$\_$2.5/ measurement is applied as an index of air particle quality.

• 한국식품과학회지
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• 제22권1호
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• pp.33-37
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• 1990

튀김유의 품질평가 방법으로서 high performance size exclusion chromatography를 이용하여 이중체, 다중체 등의 중합체를 보다 신속하게 분리할 수 있었다. 단일체 triglyceride는 가열시간이 경과함에 따라 감소하는 경향을 나타났으나, 복합처리제를 처리한 처리구의 경우에는 감소속도가 현저히 늦어지는 경향을 나타냈다. 단일체 triglyceride와 극성지질 함량사이에는 좋은 상관관계를 나타냈으며, 회기직선의 기울기에 있어서는 처리구와 대조구 모두 거의 같은 경향을 나타났다. 이러한 방법에 의하면, 단일체 중성지질 함량이 71% 이하로 저하된 튀김유는 폐기되어야 하며, 이 값은 극성지질 함량 27%에 대응하는 측정값이다.

• Bulletin of the Korean Chemical Society
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• 제27권6호
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• pp.863-868
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• 2006

The partial least squares (PLS-1) calibration model based on spectrophotometric measurement, for the simultaneous determination of sulfite and sulfide is described. This method is based on the difference between the rate of the reaction of sulfide and sulfite with Malachite Green in pH 7.0 buffer solution and at 25 ${^{\circ}C}$. The absorption kinetic profiles of the solutions were monitored by measuring the decrease in the absorbance of Malachite Green at 617 nm in the time range 10-180 s after initiation of the reactions with 2 s intervals. The experimental calibration matrix for partial least squares (PLS-1) calibration was designed with 24 samples. The cross-validation method was used for selecting the number of factors. The results showed that simultaneous determination could be performed in the range 0.030-1.5 and 0.030-1.2 $\mu$g m$L ^{-1}$ for sulfite and sulfide, respectively. The proposed method was successfully applied to simultaneous determination of sulfite and sulfide in water samples and whole human blood.

• 대한물리치료과학회지
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• 제8권1호
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• pp.851-857
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• 2001

Objectives: The objective of this study was to investigate the associated factors of low back pain in measurement of women. Methods: The data were collected from women who visited Physical Examination Center of hospital located in Daegu from July 20, 2000 to September 29, 2000. Data from 36 normal in the women. Results: The experience rate for low back pain was 58.3%. The mean age is 56 years. The the lumbar spine of healthy women in age($50\sim59$) was 73.4%, the lumbar spine of women low back pain in age($50\sim59$) was 66.7%, Variables significantly associated with low back pain were weight, education, Exercise time, menopause existence, occupation(p<0.05). The experience for LBP increased as weight increased(Odds ratio = 999.000). The experience for LBP increased as Exercise time decreased(Odds ratio = 1.090), The experience for LBP increased as menopause existence increased(Odds ratio = 0.7111), However all three variables had significant relationship. Conclusions: Results from this study indicated that a statistically significant association between LBP and weight, education. Exercise time, menopause existence, occupation, smoking in $x^2$-test. In logistic regression test. there were related variables.

• Journal of Preventive Medicine and Public Health
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• 제10권1호
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• pp.134-137
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• 1977

The most efficient method for reducing the organic content of dilute liquid waste is by aerobic-biological treatment. Basically, the organisms responsible for treatment possess the ability to decompose complex organic compounds and to use the energy so liberated for their bodily functions: reproduction, growth, locomotion and so on. That part of organic matter used to produce energy is converted to the essentially stable end products of carbon dioxide, water and ammonia, while the remainder is converted to new cells which can be settled and thus removed from the liquid before the waste is discharged to the receiving body water. Oxygen must be supplied continuously during the aerobic process. In the field of sewage treatment the Warburg respirometer is used mainly for the measurement of the oxygen uptake of samples. In this experiment the Warburg constant volume respirometer was used to determine the oxygen uptake by bacteria in the presence of various glucose concentrations. The rate of oxygen uptake by the bacteria was expressed as the respiratory quotient. The result indicated that the oxygen uptake was proportional to the glucose concentration. The expecting equation of the regression line was Y=7.7+0.12X where Y: respiratory quotient, ${\mu}l.\;O_2$ taken up/mg. dry wt. bacterium/hr. X: concentration of glucose, mg/l

• Child Health Nursing Research
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• 제14권3호
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• pp.261-268
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• 2008

Purpose: This study was conducted to estimate the prevalence of questionable development according to developmental screening testing for children, and to explore biological and environmental risk factors of developmental delays. Method: The study participants were 153 children under two years of age. A questionnaire and Home Observation for measurement of the Environment (HOME) inventory were used to collect data, and Korean Denver II was administered. Results: The overall prevalence of questionable development was 11.1%. Significant differences in biological factors between the normal development group and questionable development group were the rate of prematurity, twins, the educational level of mother and father's and the presence of an illness in the mother (p<.10). Maternal acceptance in HOME was significantly different between the two groups. The factors related to questionable development that were significant in the logistic regression analysis were prematurity (OR=3.56, p=.026), and maternal acceptance in HOME score (OR=.629, p=.028). Conclusion: Early developmental screening tests seem necessary for all children, especially for prematurely born children. Also, child rearing environments were identified as significant factors in the development of all children. These findings suggest that the HOME scores might be useful in identifying children at risk for developmental delays, and that interventions for these children will probably be more effective if their mothers are helped to provide a more appropriate social environment.