• 한국치위생학회지
• /
• 제21권5호
• /
• pp.655-666
• /
• 2021

Objectives: A systematic review and a meta-analysis were performed investigate the factors related to turnover intention of dental hygienists in Korea. Methods: Literature between 2000 and January 2021 were used to support the meta-analysis, which focused on 21 factors extracted from 50 articles using a random effects model. The correlation coefficient, r, in the effect size was calculated. Results: Substantial literature was published after 2011 (76%); in academic journals (74%); and targeted nonmetropolitan areas (40%). Lawler's turnover intention tool was used in several studies. The effect size for each ecosystem was in the order of microsystem (r=0.325), mesosystem (r=0.307), macrosystem (r=0.259), exosystem (r=0.176), and individuals (r=0.171). The random-effects model indicated an overall average of r=0.311. The factor that showed a large effect size in relation to turnover intention was organizational commitment of the microsystem (r=-0.594). Furthermore, mesosystem reward (r=- 0.416), microsystem burnout (r=0.464), job stress (r=0.408), and job satisfaction (r=-0.405) were identified as other major factors. Conclusions: To lower the turnover rate of dental hygienists, it is important to focus on factors belonging to the microsystem, and mesosystem reward.

• 한국해안해양공학회지
• /
• 제3권1호
• /
• pp.54-64
• /
• 1991

현지해안의 표사이동량을 정확히 예측하기 위해서는, 표사이동의 주외력요소(agitation force)인 다방향불규칙 파랑의 천수변형 특성 및 그들에 의해서 발생하는 표사수송 흐름으로서의 해빈류에 대해서 충분히 파악해 둘 필요가 있다. 그러나, 현재 제안되어져 있는 연안류 및 이안류를 포함하는 해빈류 model은 대부분 규칙파 이론에 근거를 두고 파랑특성을 표현하고 있기 때문에 파랑의 불규칙성 및 방향분산성을 고려한 해빈류에 대한 연구는 극히 제한되어져 있다. 본 연구는 다방향불규칙 파랑에 의한 연안유속의 산정에 관한 기초적 연구로서, 주로 파별해석법에 의한 수치계산법을 제안함과 동시에 그들의 수치해석결과를 평면수리실험과 비교함으로써 그 타당성을 검토하였다.

• Journal of the Korean Data and Information Science Society
• /
• 제24권6호
• /
• pp.1439-1448
• /
• 2013

확률화 블록계획법이나 교차된 이원분류표에 대한 분산분석과 오차제곱합의 성질은 널리 알려져있다. 본 논문에서는 인자에 따른 수준에 또 다른 인자들이 내포되어 있는 지분계획 특히 이단계 지분계획에 대하여 구조적 특징을 설명하고 오차제곱합의 성질에 대하여 살펴보았다. 또한 이단계 지분계획의 활용으로 크로스오버 계획을 소개하고 생물학이나 약학 등의 분야에서 많이 사용되는 동등성 검정의 신뢰구간 구축에 대하여 설명하였고 실제자료와 SPSS 통계 페키지를 이용하여 분석함으로서 응용성을 부각시켰다.

• Physical Therapy Rehabilitation Science
• /
• 제11권3호
• /
• pp.304-310
• /
• 2022

Objective: Mild cognitive impairment (MCI) is a condition in which cognitive and executive functions are reduced, and older adults with MCI are ten times more likely to develop dementia than healthy older adults. Expression of brain-derived neurotrophic factor (BDNF) through aerobic exercise is associated with increased cognitive and executive functions. in this review, randomized controlled trials (RCTs) on the effects of aerobic exercise on BDNF in individuals with mild cognitive impairment are summarized and qualitatively and quantitatively analyzed to suggest the necessity of aerobic exercise. Design: a systematic review and meta-analysis. Methods: RCTs were searched for changes in BDNF through aerobic exercise using four international databases. Quality assessment and quantitative analysis were performed using RevMan 5.4. Quantitative analysis was quantified with a standardized mean difference (SMD) and presented as a random effect model. Results: Three RCTs evaluated BDNF in 123 patients with MCI. There was a significant improvement in the experimental group that performed aerobic exercise compared to the control group. The results analyzed using the random effects model were SMD = 0.48. Conclusions: In this review, we reported the effects and mechanisms of aerobic exercise in individuals with MCI. As a result of synthesizing RCTs that performed aerobic exercise, a significant increase in BDNF was confirmed.

• Physical Therapy Rehabilitation Science
• /
• 제12권2호
• /
• pp.115-122
• /
• 2023

Objective: A previous study reported that cardiovascular training (CT) decreased interleukin-6 (IL-6), a pro-inflammatory cytokine with bidirectional effects. However, because of conflicting results of increasing and decreasing IL-6 levels in stroke patients, it is essential to clarify the effects of CT on IL-6 levels in this population. Therefore, this review aimed to investigate the effects of CT on IL-6 levels in stroke patients through a meta-analysis of randomized controlled trials (RCTs), synthesizing and analyzing the effects qualitatively and quantitatively. Design: A systematic review and meta-analysis of randomized controlled trials. Methods: In this review, conducted in April 2023, electronic databases (Web of Science, CINAHL, Embase, MEDLINE, Google Scholar) were searched to ascertain the effects of CT on IL-6 levels in stroke patients. For qualitative evaluation, ReVMan, provided by the Cochrane Group, was used, and for quantitative evaluation, a random-effects model and SMD (Standardized Mean Difference) were used. Results: Three RCTs measured IL-6 in 117 patients with stroke. The experimental group to which CT was applied showed no significant change compared to the control group.The result of analysis using the random effect model is SMD=-0.23; 95% confidence interval, -0.66 to 0.20. Conclusions: CT does not affect IL-6 levels in stroke patients. These results suggest that CT can be applied regardless of its positive or negative effect on IL-6 levels in stroke patients.

• Communications for Statistical Applications and Methods
• /
• 제27권3호
• /
• pp.349-363
• /
• 2020

Penalized spline is a suitable nonparametric approach in estimating mean model in small area. However, application of the approach in informative sampling in a published article is uncommon. We propose a semiparametric mixed-model using penalized spline under informative sampling to estimate mean of small area. The response variable is explained in terms of mean model, informative sample effect, area random effect and unit error. We approach the mean model by penalized spline and utilize a penalized spline function of the inclusion probability to account for the informative sample effect. We determine the best and unbiased estimators for coefficient model and derive the restricted maximum likelihood estimators for the variance components. A simulation study shows a decrease in the average absolute bias produced by the proposed model. A decrease in the root mean square error also occurred except in some quadratic cases. The use of linear and quadratic penalized spline to approach the function of the inclusion probability provides no significant difference distribution of root mean square error, except for few smaller samples.

• Journal of Mechanical Science and Technology
• /
• 제19권6호
• /
• pp.1280-1289
• /
• 2005

This paper presents the effects of corrosion environments of failure pressure model for buried pipelines on failure prediction by using a failure probability. The FORM (first order reliability method) is used in order to estimate the failure probability in the buried pipelines with corrosion defects. The effects of varying distribution types of random variables such as normal, lognormal and Weibull distributions on the failure probability of buried pipelines are systematically investigated. It is found that the failure probability for the MB31G model is larger than that for the B31G model. And the failure probability is estimated as the largest for the Weibull distribution and the smallest for the normal distribution. The effect of data scattering in corrosion environments on failure probability is also investigated and it is recognized that the scattering of wall thickness and yield strength of pipeline affects the failure probability significantly. The normalized margin is defined and estimated. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

• 한국노년학
• /
• 제29권4호
• /
• pp.1413-1425
• /
• 2009

본 연구는 서울 및 춘천지역 거주 중·고령자를 대상으로 부양책임감이 나이와 세대에 따라 어떻게 변화하고 있는지 분석하였다. 본 연구는 4차에 걸쳐 진행된 한림고령자패널 자료를 대상으로 램덤상수모델을 통해 세대 효과와 연령효과를 분석하였다. 본 연구에서는 실바흐(Sealbach)가 개발한 부양책임감 척도를 사용하였으며, 출생연도 1940년을 기준으로 이전 세대는 식민지·전쟁경험세대로, 이후세대는 산업화 민주화 세대로 구분하였다. 분석결과는 다음과 같다. 첫째, 식민지·전쟁경험세대는 산업화·민주화 세대에 비해 부양책임감이 높은 것으로 나타났다. 둘째, 연령효과를 살펴보면 일반적인 예상과는 달리 나이와 부양책임감 사이에는 통계적으로 유의미한 결과를 보이지 않는다. 서구의 연구는 노인부양의 어려움에 대한 인식이나 타인을 부양해야 한다는 의무감의 종료 등으로 인해 나아가 많은 노인일수록 부양책임감이 감소한다는 연구 결과를 제시하고 있는데, 이러한 측면이 우리나라에서는 적용되지 않는 것으로 보인다. 첫째와 둘째 결과에 비추어 볼 때 노인층이 장년층에 비해 부양책임감이 높은 것은 연령효과라기 보다는 세대효과일 가능성이 크다. 셋째, 남성이 여성에 비해, 서울이 춘천에 비해, 면지역 거주자가 동지역 거주자에 비해 부양책임감이 높은 것으로 나타났고, 주관적 건강 상태가 좋을수록, 학력 및 소득이 높을수록 부양책임감은 낮아지는 것으로 나타나고 있다.

• 대한토목학회논문집
• /
• 제10권4호
• /
• pp.53-66
• /
• 1990

산악의 영향을 받는 지역에서 비정상성 평균을 사용하는 G.C.모델에 의하여 총강우량의 우량곡면을 구성하였다. 구성된 우량곡면에 2차원 프리에 해석을 실시하여 강우의 주기성분을 분리하였다. 강우의 지엽성분, 즉 강우잔차는 우량곡면에서 주기성분을 제거하여 얻은 강우잔차를 균일한 무작위장의 표본함수라고 가정해서 이 무작위장의 특성을 자기상관함수로 나타냈다. 자기상관함수를 변환하여 스팩트럼 밀도를 구했고, 이 결과를 토대로 한강, 금강유역의 환상스팩트럼 분포함수의 모델을 제안했다.

• 대한기계학회논문집B
• /
• 제27권3호
• /
• pp.286-293
• /
• 2003

The unsteady flow characteristics and associated blade tonal noise of a cross-flow fan are predicted by computational methods. The incompressible Navier-Stokes equations are time-accurately solved for obtaining the pressure fluctuations between the rotating blades and the stabilizer. and the sound pressure is predicted using Curie's equation. The discrete noise characteristics of three impellers with a uniform and two random pitch (type-A and -B) blades are compared by their SPL (Sound Pressure Level) spectra. and the frequency modulation characteristics of the BPF (Blade Passing Frequency) noise are discussed. Besides. a mathematical model is proposed for the prediction of discrete blade tonal noise and is validated with available experimental data. The fan performance is also compared with experimental data. indicating that the random pitch effect does not significantly alter the performance characteristics at ${\phi}$ 〉 0.4