• 대한기계학회논문집B
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• 제21권12호
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• pp.1710-1719
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• 1997

An approximate analytical solution for the initial transient process of close-contact melting occurring between a phase change material kept at its melting temperature and an isothermally heated flat surface is derived. The model is so developed that it can cover both rectangular and circular cross-sectional solid blocks. Normalization of simplified model equations in reference to the steady solution enables the solution to be expressed in a generalized form depending on the liquid-to-solid density ratio only. A selected result shows an excellent agreement with the previously reported numerical data, which justifies the present approach. The solution appears to be capable of describing all the fundamental characteristics of the transient process. In particular, dependence of the solid descending velocity oft the density ratio at the early stage of melting is successfully resolved. The effects of other parameters except the density ratio on the transient behaviors are efficiently represented via the steady solution implied in the normalized result. A simple approximate method for estimating the effect of convection on heat transfer across the liquid film is also proposed.

• Journal of Acupuncture & Meridian Studies
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• 제11권6호
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• pp.355-360
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• 2018

Introductions: Pneumothorax is the most frequent severe acupuncture-related adverse event occurring at the GB 21 acupoint. This study used ultrasonography (US) to measure the depth of the GB 21 acupoint in adults and assessed its applicability for ensuring safe acupuncture practices. Materials and methods: A US probe was used to measure the vertical depth from the skin to the pleural line of the apex of the lungs at the right and left GB 21 acupoints. The sex, age, body weight, height, and body mass index of each person were recorded. Student t test and generalized estimating equations were used for statistical analysis. Results: Sixty women and 41 men with a median age of 29 years were included in this study. The depth of GB 21 increased with body weight, height, and body mass index (p < 0.001). The mean depth of GB 21 in men (17.4 mm) was greater than that in women (14.6 mm; p < 0.001). The depth difference between the right and left shoulders was significant in men (p < 0.001) but not in women. Conclusions: US can be used to measure GB 21 acupoint depth. Further control studies on its use to ensure safe clinical practices, including preventing acupuncture-related pneumothorax, are warranted.

• Child Health Nursing Research
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• 제28권2호
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• pp.132-141
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• 2022

Purpose: This study examined the effects of an educational program for fathers on improving father-infant interactions, child-rearing knowledge, and attachment. Methods: In this quasi-experimental study, the participants were recruited by convenience sampling among fathers with infants (2-6 months of age) residing in three districts of Seoul. Fifteen participants in the experimental group and 17 participants in the control group completed the follow-up investigation. A 5-week online and offline intervention program with five sessions was provided to the experimental group. The data were analyzed using generalized estimating equations (GEEs). Results: There was a significant difference in the change in father-infant interaction scores of the experimental group, especially in the caregiver aspect with a significance level of .100 in time and group-to-group interactions (B=6.46, p=.051, 95% confidence interval [CI]=-0.02-12.94). The changes between the groups and times were not statistically significant when it came to infant development knowledge and father-infant attachment. Conclusion: We conclude that hybrid online and offline education should be implemented as an effective method to improve fathers' interactions with their children based on accurate knowledge about infant development.

• 응용통계연구
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• 제23권1호
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• pp.13-28
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• 2010

혼합분포를 가정한 신용평가연구에서 부도차주를 정상으로 예측하거나 정상차주를 부도로 예측하는 오류를 최소화하는 분류점을 추정하는 방법을 토론한다. 확률변수 스코어와 정상과 부도상태의 모수공간으로 정의된 확률밀도함수들에 대하여 강력검정과 일반화가능도비검정을 이용하여 최적분류점의 추정방법을 제안하고, ROC와 CAP 곡선에서 분류정확도를 측정하는 정확도(accuarcy)와 진실율(true rate)을 이용하여 이 측도를 최대로 하는 최적분류점을 확률밀도함수의 관계식으로 추정하는 방법을 제안한다. 다양한 정규분포에서 가설검정, 정확도 그러고 진실율을 이용하는 세가지 방법의 최적분류점을 구하고 각최적분류점에 대응하는 제 I 종과 제 II 종 오류합의 크기를 비교하여 효율성을 토론한다.

• Journal of Korean Biological Nursing Science
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• 제22권4호
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• pp.260-270
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• 2020

Purposes: Sepsis is a critical condition in which nurses should detect clinical manifestations and provide early intervention to prevent unwanted serious conditions in the patients. The initial occurrence and management of sepsis take place in general units, but there is a lack of knowledge in nurses. The purpose of this study was to examine the effects of a case-based sepsis education program and compare the case-based education program with and without smartphone applications. Methods: A quasi-experimental pre-test-post-test design with a control group was used. We provided a case-based education program with and without smartphone applications to the nurses and tested the effects of the program on knowledge, the accuracy of sepsis assessment, and self-efficacy as outcome variables. A total of 60 nurses in general units participated. To test differences in knowledge, the accuracy of sepsis assessment, and self-efficacy regarding sepsis between the groups over time, a mixed-design ANCOVA was used for parametric analysis, and generalized estimating equations (GEE) were used for nonparametric analysis. Results: There were significant differences in knowledge, the accuracy of sepsis assessment, and self-efficacy between the groups and within the groups over time. The intervention groups treated with the case-based education program showed improved outcome variables compared to the control group. There was no difference between case-based education with the smartphone application or without the application. Conclusions: The case-based education improved knowledge, the accuracy of sepsis assessment, and self-efficacy in the care of sepsis by nurses working in the general wards. The results suggest that the case-based education program for nurses was effective and eventually improved patient health outcomes.

• 한국콘텐츠학회논문지
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• 제16권10호
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• pp.411-419
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• 2016

본 연구는 가구소득 수준과 가구소득 대비 의료비 지출 비중의 관련성을 규명하고자 한다. 자료 분석을 위해 한국보건사회연구원과 국민건강보험공단이 공동 주관하는 한국의료패널 2010-2011년 연간 데이터를 이용하였다. 독립변수의 효과가 2010년과 2011년에 따라 변화하는지 확인하기 위해 연도와 독립변수 간의 상호작용 효과를 확인하였으며, 연도에 따라 상호작용 효과가 나타난 요인은 연도별로 분리하여 일반화 추정 방정식 방법을 이용한 선형회귀분석을 수행하였다. 의료 이용을 한 사람들을 대상으로 가구소득 대비의료비 지출 비중과 관련성을 가진 요인들을 살펴본 결과, 가구소득 수준이 높을수록 의료비 지출 비중이 낮음을 확인할 수 있었다. 저소득층의 의료비 부담을 줄여주는 정책을 마련해야 할 것이다.

• 한국농공학회지
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• 제44권5호
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• pp.96-105
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• 2002

As an useful water purification system for non-point source pollution in rural watersheds, interests in constructed wetlands are growing at home and abroad. It is well known that constructed wetlands are easily installed, no special managemental needs, and more flexible at fluctuating influent loads. They have a capacity for purification against nutrient materials such as phosphorus and nitrogen causing eutrophication of lentic water bodies. The Constructed Wetland Design Model (CWDM), developed through this study is consisted mainly of Database System, Runoff-discharge Prediction Submodel, Water Quality Prediction Submodel, and Area Assessment Submodel. The Database System includes data of watershed, discharge, water quality, pollution source, and design factors for the constructed wetland. It supplies data when predicting water quality and calculating the required areas of constructed wetlands. For the assessment of design flow, the GWLF (Generalized Watershed Loading Function) is used, and for water quality prediction in streams estimating influent pollutant load, Water Quality Prediction Submodel, that is a submodel of DSS-WQMRA model developed by previous works is amended. The calculation of the required areas of constructed wetlands is achieved using effluent target concentrations and area calculation equations that developed from the monitoring results in the United States. The CWDM is applied to Bokha watershed to appraise its application by assessing design flow and predicting water quality. Its application is performed through two calculations: one is to achieve each target effluent concentrations of BOD, SS, T-N and T-P, the other is to achieve overall target effluent concentrations. To prove the validity of the model, a comparison of unit removal rates between the calculated one from this study and the monitoring result from existing wetlands in Korea, Japan and United States was made. As a result, the CWDM could be very useful design tool for the constructed wetland in rural watersheds and for the non-point source pollution management.

• Safety and Health at Work
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• 제6권3호
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• pp.240-248
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• 2015

Background: Recovery from fatigue is important in maintaining night workers' health. This study compared the course of self-reported recovery after 2-week 12-hour schedules consisting of either night shifts or swing shifts (i.e., 7 night shifts followed by 7 day shifts) to such schedules consisting of only day work. Methods: Sixty-one male offshore employees-20 night workers, 16 swing shift workers, and 25 day workers-rated six questions on fatigue (sleep quality, feeling rested, physical and mental fatigue, and energy levels; scale 1-11) for 14 days after an offshore tour. After the two night-work schedules, differences on the $1^{st}$ day (main effects) and differences during the follow-up (interaction effects) were compared to day work with generalized estimating equations analysis. Results: After adjustment for confounders, significant main effects were found for sleep quality for night workers (1.41, 95% confidence interval 1.05-1.89) and swing shift workers (1.42, 95% confidence interval 1.03-1.94) when compared to day workers; their interaction terms were not statistically significant. For the remaining fatigue outcomes, no statistically significant main or interaction effects were found. Conclusion: After 2-week 12-hour night and swing shifts, only the course for sleep quality differed from that of day work. Sleep quality was poorer for night and swing shift workers on the $1^{st}$ day off and remained poorer for the 14-day follow-up. This showed that while working at night had no effect on feeling rested, tiredness, and energy levels, it had a relatively long-lasting effect on sleep quality.

• Journal of Periodontal and Implant Science
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• 제47권4호
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• pp.240-250
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• 2017

Purpose: The aim of this study was to analyze the prevalence and risk indicators of peri-implantitis in Korean patients with history of periodontal disease. Methods: A total of 444 patients with 1,485 implants were selected from patients who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital between July 2014 and June 2015. A group with a history of peri-implantitis (HP) (370 patients with 1,189 implants) and a group with a current peri-implantitis (CP) (318 patients with 1,004 implants) were created based on the radiographic and clinical assessments of implants. The prevalence of peri-implantitis was calculated at both the patient and implant levels. The influence of risk variables on the occurrence of peri-implantitis was analyzed using generalized estimating equations analysis. Results: The prevalence of peri-implantitis in the HP and CP groups ranged from 6.7% to 19.7%. The cumulative peri-implantitis rate in the HP group estimated with the Kaplan-Meier method was higher than that in the CP group over the follow-up period. Among the patient-related risk variables, supportive periodontal therapy (SPT) was the only significant risk indicator for the occurrence of peri-implantitis in both groups. In the analysis of implant-related variables, implants supporting fixed dental prosthesis (FDP) and implants with subjective discomfort was associated with a higher prevalence of peri-implantitis than single implants and implants without subjective discomfort in the HP group. The presence of subjective discomfort was the only significant implant-related variable predictive of peri-implantitis in the CP group. Conclusions: Within the limitations of this study, the prevalence of peri-implantitis in Korean patients with a history of periodontal disease was similar to that reported in other population samples. Regular SPT was important for preventing peri-implantitis. Single implants were found to be less susceptible to peri-implantitis than those supporting FDP. Patients' subjective discomfort was found to be a strong risk indicator for peri-implantitis.

• 한국건설관리학회논문집
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• 제6권4호
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• pp.152-163
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• 2005

깊은기초 시공시에 기초파일의 항타작업은 인접구조물 등에 진동을 야기하고 소음으로 인해 주변지역에 민원을 발생시키고있다. 이러한 문제로 진동 $\cdot$ 소음 문제를 직접 야기시키는 직타공법 보다는 주로 저소음 $\cdot$ 저진동 공법 인 천공 후 타격공법을 적용하는 사례가 증가하고 있다. 그러나 천공 후 타격공법도 일정거리 이내에서 시공을 할 경우 진동 $\cdot$소음을 유발시컥 민원으로 인한 공기지연을 초래하고 있는 실정이다. 따라서 본 연구에서는 건설 구조물의 구축을 위한 기초공사현장에서 말뚝공사를 할 때 발생하는 진동 $\cdot$ 소음을 천공 후 타격공법을 대상으로 지반조건이 상이한 7개의 현장에서 실측하여 이를 제정된 허용규제기준에 따른 적정 이격허용거리를 회귀분석 식으로 제시하고 있다. 이러한 연구 결과는 기초파일 공사시에 요구되는 적정 거리확보를 위한 기준역할을 하도록 하며, 인접 구조물이나 주민의 환경적 피해를 최소화하고, 나아가 공기지연으로 발생되는 클레임을 방지하는데 활용성을 갖도록 함에 연구의 목적이 있다.