• Safety and Health at Work
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• 제8권3호
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• pp.276-281
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• 2017

Background: The present study was carried out to assess the relationship between sickness absence and occupational stress, sleep quality, and amplitude and stability of circadian rhythm as well as to determine contributing factors of sickness absence. Methods: This cross sectional study was conducted on 400 randomly selected employees of an Iranian gas company. The data were collected using Pittsburgh sleep quality index, Karolinska sleepiness scale, circadian type inventory, and Osipow occupational stress questionnaires. Results: The mean age and job tenure of the participants were $33.18{\pm}5.64years$ and $6.06{\pm}4.99years$, respectively. Also, the participants had been absent from work on average 2.16 days a year. According to the results, 209 participants had no absences, 129 participants had short-term absences, and 62 participants had long-term absences. The results showed a significant relationship between short-term absenteeism and amplitude of circadian rhythm [odds ratio (OR) = 6.13], sleep quality (OR = 14.46), sleepiness (OR = 2.08), role boundary (OR = 6.45), and responsibility (OR = 5.23). Long-term absenteeism was also significantly associated with amplitude of circadian rhythm (OR = 2.42), sleep quality (OR = 21.56), sleepiness (OR = 6.44), role overload (OR = 4.84), role boundary (OR = 4.27), and responsibility (OR = 3.72). Conclusion: The results revealed that poor sleep quality, amplitude of circadian rhythm, and occupational stress were the contributing factors for sickness absence in the study population.

• 대한토목학회논문집
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• 제14권1호
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• pp.83-91
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• 1994

뒤틀림을 받는 손상 관형 단면의 강도 및 거동을 파악하기 위한 효율적인 해석기법을 제시하였다. 단면의 뒤틀림을 고려키 위하여 유한요소 해석법을 이용하였으며 부재의 유한요소 해석시 발생하는 국부 불안정에 의한 하중-변형 응답의 발산 문제를 해결하기 위하여 손상부위만에 대하여 유한요소해석을 수행, 모멘트-곡률 관계를 일반화하여 이를 부재해석의 입력자료로 제공하였다. 광범위한 실용판형 부재를 포함하는 데이타베이스를 구축하여 이에 대한 복회귀분석을 수행, 일반화된 모멘트-곡률관계식을 제시하여 연구의 실용성을 제고 하였다.

• 노동경제논집
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• 제31권2호
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• pp.103-128
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• 2008

본 연구는 "한국노동패널조사" 자료를 사용하여 노동조합이 임금에 미치는 효과를 패널 분석하였다. 횡단면 분석을 통하여 구한 노동조합이 임금상승에 미치는 효과는 약 4.6%로 추정되었다. 고정효과 모델을 통하여 추정된 노조의 임금상승효과는 약 2.1%로 상당히 그 효과가 감소하였음을 알 수 있다. 따라서 보이지 않는 근로자의 특성과 노조가 있는 기업에 종사하며 노동조합에 가입하는 의사결정과 양(+)의 상관관계가 존재함을 유추해 볼 수 있으며 기존의 횡단면 분석의 연구 결과가 상당 부분 상향 편의되었음을 유추해 볼 수 있다.

• 센서학회지
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• 제6권2호
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• pp.87-94
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• 1997

이 논문에서는 비자성 연선도체의 단면적을 검출하는 솔레노이드 센서의 임피던스 해석이 다루워졌다. 도전체의 전기 자기적 특성들을 검출하기 위하여, 관통형 코일로 비파괴검사 와전류 센서를 선택하였다. Maxwell 방정식을 풀어서 도체봉을 가진 센서의 규격화 임피던스 응답이 모델링되고 그 결과들이 연선에 확장되었다. 연선구조에 미치는 기하학적 성질이 검토되고 수치 해석과 실험결과 또한 주어진다.

• 대한의용생체공학회:의공학회지
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• 제5권1호
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• pp.47-54
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• 1984

In order to research the flow in the thin wall compliant tube, this present study is attempt to measure the cross sectional area according to change of external pressure and flow by ultrasonic method different from willy used impedance technique for flow analysis about one dimensional Steads flow. The experimental results are as follows. 1) Measurement of cross sectional area ratio by ultrasonic method by comparison with experimental results of impedance technique & theoretical results were well consent. 2) Pressure difference of upstream and down stream is alwap's maximum range at 0.4 < $\alpha$ <0.5, and have no connection with changing external pressure. 3) when the external pressure is fixed and resistance is varied, Self excited oscillation occurs in the region at 0.5 < $\alpha$ <0.6, and oscillation disappear almost at R2>=1.2

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.184-190
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• 2015

On wide variety of fields, studies on active twist control are becoming more active. For effective twist control, blades have to have low torsional stresses with high torsional deformations to the same magnitude of torque acting on its cross-section. In this study, 2D sectional analysis and 3D finite element analysis were made for 5 different blades with each having different cross - sections which have different spars. The results from 2D sectional analysis, were then put into 3D blade deformation and stress calculations which lead to analysis. Outcomes from 2D and 3D analysis, showed that on the same torque and concentrated load conditions, the blade with 'C' shaped spar was the best of all the blades which were used in this study.

• 한국수학교육학회지시리즈A:수학교육
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• 제42권2호
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• pp.111-119
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• 2003

This research discussed a general concept on the qualitative research methods in mathematics education. It provided a classification of research methods in mathematics education. It also described research trends in mathematics education. It addressed how research design facilitates formulating a research problem, selecting a research design, choosing who and what to study, deciding how to approach Participants, selecting means to collect data choosing how to analyzing data, and interpreting data and applying the analysis. This study addressed the issues involved in choosing relevant populations and in selecting and sampling qualitative data. It described how populations are conceptualized and distinguished between probability sampling and criterion based selection. It discussed not only data arrangement such as, cross-sectional and categorical indexing, non-cross- sectional data organization, but also diagram flow chart matrix, cognitive map, family tree to facilitate analyzing data.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.259-262
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• 2005

Numerous studies showed that safety and serviceability of many concrete infrastructures and buildings built in 1970's have capacity less than their design capacities and thereby require immediate retrofitting. Currently, these aged concrete structure are being repaired using many repair and strengthening methods developed in the past. Therefore, in this study, a repairing and strengthening method for retrofitting high strength concrete columns that can effectively improve the performance of high strength concrete columns is developed. The square high strength concrete column's cross-sectional shape is modified to octagonal shape by attaching precast members on the surface of the column. Then, the octagonal column surface is wrapped using Carbon Fiber Sheets (CFS). The method allowed the maximum usage of confinement effect of externally wrapped CFS, which resulted in improved strength and ductility of repaired high strength concrete columns.

• International Journal of Advanced Culture Technology
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• 제7권1호
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• pp.20-27
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• 2019

This study was designed to examine the affect health promotion behavior to emotional happiness for 20-30's in Korea through cross-sectional descriptive research. There were a total of 279 people who participated in this study, 198(71.0%) were males and 81(29.0%) were females. The data collection period was from December 1 to 15, 2018. The tools used to measure health promotion behaviors were HPB (Health Promotion Behavior) developed by Walker et al., and emotional happiness was PANAS (Positive and Negative Affect Scale) by Developed by Watson et al., All data was analyzed using SPSS 18.0 program. As a result of analysis, 62 (49.6%) were solving interpersonal problems and stress relief while drinking, and the people who ate twice a day were most frequent. In conclusion, health promotion behaviors have a strong correlation with emotional happiness. Based on the above results, it was suggested that the program of happiness for lining in the 20-30s age groups should strengthen the contents of health responsibility, guidance of substance abuse, formation of social relations and self actualization.

• Child Health Nursing Research
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• 제29권4호
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• pp.252-259
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• 2023

Purpose: Falls are a common cause of unintentional injuries in infants. This study was conducted to examine the patterns of healthcare utilization following infant falls in South Korea. Methods: This cross-sectional descriptive study utilized an online survey designed to gather information regarding the general characteristics of parents and infants, fall-related variables, and healthcare use. Results: The most serious falls identified by parents occurred at an average infant age of 6.97 months. Most fall incidents took place indoors (95.7%), and many occurred under the supervision of caregivers (68.0%). Following the fall, 36.4% of the participants used healthcare services. Logistic regression analysis revealed that healthcare use following an infant fall was significantly associated with being a firstborn child (odds ratio [OR]=5.32, 95% confidence interval [CI], 2.19-15.28) and falling from a caregiver's arms (OR=4.22; 95% CI, 1.45-13.68). Conclusion: To prevent and decrease the frequency of infant falls, improvements are needed in both the domestic environment and parenting approaches.