• 응용통계연구
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• 제25권6호
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• pp.1037-1047
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• 2012

The generalized linear mixed model(GLMM) is widely used in fitting categorical responses of clustered data. In the numerical approximation of likelihood function the normality is assumed for the random effects distribution; subsequently, the commercial statistical packages also routinely fit GLMM under this normality assumption. We may also encounter departures from the distributional assumption on the response variable. It would be interesting to investigate the impact on the estimates of parameters under misspecification of distributions; however, there has been limited researche on these topics. We study the sensitivity or robustness of the maximum likelihood estimators(MLEs) of GLMM for counts data when the true underlying distribution is normal, gamma, exponential, and a mixture of two normal distributions. We also consider the effects on the MLEs when we fit Poisson-normal GLMM whereas the outcomes are generated from the negative binomial distribution with overdispersion. Through a small scale Monte Carlo study we check the empirical coverage probabilities of parameters and biases of MLEs of GLMM.

• Journal of Chest Surgery
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• 제49권5호
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• pp.337-343
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• 2016

Background: Recent developments in surgical techniques and hospital care have led to improved outcomes following total anomalous pulmonary venous return (TAPVR) repair. However, the surgical repair of TAPVR remains associated with a high risk of mortality and need for reoperation. We conducted this retrospective study to evaluate mid-term outcomes following in situ TAPVR repair without total circulatory arrest (TCA), and to identify the risk factors associated with surgical outcomes. Methods: We retrospectively reviewed 29 cases of surgical intervention for TAPVR conducted between April 2000 and July 2015. All patients were newborns or infants who underwent in situ TAPVR repair without TCA. Results: Four anatomic subtypes of TAPVR were included in this study: supracardiac (20 cases, 69.0%), cardiac (4 cases, 13.8%), infracardiac (4 cases, 13.8%), and mixed (1 case, 3.4%). The median follow-up period for all patients was 42.9 months. Two (6.9%) early mortalities occurred, as well as 2 (6.9%) cases of postoperative pulmonary venous obstruction (PVO). Preoperative ventilator care (p=0.027) and preoperative PVO (p=0.002) were found to be independent risk factors for mortality. Conclusion: In situ repair of TAPVR without TCA was associated with encouraging mid-term outcomes. Preoperative ventilator care and preoperative PVO were found to be independent risk factors for mortality associated with TAPVR repair.

• Communications for Statistical Applications and Methods
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• 제23권6호
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• pp.575-585
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• 2016

Longitudinal studies repeatedly measure outcomes over time. Therefore, repeated measurements are serially correlated from same subject (within-subject variation) and there is also variation between subjects (between-subject variation). The serial correlation and the between-subject variation must be taken into account to make proper inference on covariate effects (Diggle et al., 2002). However, estimation of the covariance matrix is challenging because of many parameters and positive definiteness of the matrix. To overcome these limitations, we propose autoregressive moving average Cholesky decomposition (ARMACD) for the linear mixed models. The ARMACD allows a class of flexible, nonstationary, and heteroscedastic models that exploits the structure allowed by combining the AR and MA modeling of the random effects covariance matrix. We analyze a real dataset to illustrate our proposed methods.

• 응용통계연구
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• 제28권2호
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• pp.241-250
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• 2015

경시적 자료 연구의 중요한 주제 중의 하나는 시간이 지남에 따라 개인의 건강 상태가 어떻게 변하는지를 추적하는 확률이다. 질병의 상태를 시간의 흐름에 따라 추적하는 것은 장기간에 걸친 임상적 관찰 연구의 계획과 분석, 그리고 질병의 예방과 치료에 중요한 의미를 지닌다. 본 논문에서는 두 다른 시점에서 각 개인의 건강 상태에 대한 조건부 확률을 추정해내는 순위 추적 확률에 대하여 연구하였다. 순위 추적 확률과 순위 추적 확률비를 추정하기 위하여 선형 혼합 효과 모형을 고려하였다. 본 논문의 방법은 아동을 대상으로 심혈관계 질환의 위험요인을 연구하는 역학 자료에 적용되었다.

• Advances in concrete construction
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• 제15권4호
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• pp.241-249
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• 2023

The unsteady mixed convection Casson type MHD nanofluid flow in the stagnation point with motile microorganism around a spinning sphere is investigated. Time dependent flow dynamics is considered. Similarity transformations have been employed to transfer the governing partial differential structure into ordinary differential structure. The impact of distinct parameters is examined via tables and graphs. The impact of rotational parameter (spin) on profiles of velocity profiles, temperature and concentration is revealed for unsteady mixed convection Casson type MHD nanofluid flow. It is observed that it is clear that rotational parameter has a great effect on non-dimensional primary velocity component but rotational parameter has a slight impact on non-dimensional secondary velocity component. The validity of the current investigation is authorized through comparing the existing outcomes with previous published literature.

• 지역사회간호학회지
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• 제29권2호
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• pp.170-183
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• 2018

Purpose: Although innovative interventions using technologies have been introduced in long-term care settings, available evidence is still anecdotal. The purpose of this study is to investigate and synthesize the outcomes of interventions using technologies delivered to nursing home residents. Methods: Published clinical trials were identified through PubMed, CINHAL, Cochrane and PsycINFO databases and manually hand-searching. Eligible studies were articles published between 1997-2016 in English or Korean with a randomized controlled trial or quasi-experimental design in which interventions using technologies were delivered to nursing home residents. Results: A total of 20 studies were selected for this review. Types of interventions using technologies were classified into the electronic documentation technology (n=1), the clinical decision support system (n=1), the safety technology (n=1), the health and wellness technology (n=10), and the social connectedness technology (n=7). Overall resident outcomes indicated that interventions using technologies improved behavioral symptoms and psycho-social outcomes, but mixed results were shown in the aspects of physical function, cognitive function, social relationship and quality of service. Conclusion: This review demonstrates that incorporating technologies into nursing home care have positive effects on residents' psycho-social outcomes and behavioral symptoms. To disseminate the effectiveness of interventions using technologies, further research is needed to determine what mechanisms underlying such relationships exist.

• 한국경제지리학회지
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• 제13권4호
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• pp.515-528
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• 2010

본 연구에서는 전반적으로 토지이용이 조밀하면서도 지역 간 주택가격의 차이가 크게 나타나는 우리나라 서울지역을 대상으로 주택가격에 영향을 미치는 요인을 분석해 보고자 한다. 특히 복합용도개발현황과 TOD 상황을 보여주는 접근성을 고려한 뉴어버니즘의 주요 개념들이 실제 주택가격에 어떠한 영향을 분석한다. 이를 위하여 모든 도시민이 일상생활을 영위하기 위하여 필요로 하는 토지이용을 거주지, 일자리, 쇼핑시설로 보고 지역에 이들의 토지이용이 혼합되어 있는 정도를 측정하는 용도혼합지표를 개발하였다. 특히 동 단위를 근린지역의 범위로 보고, 동별 토지이용의 혼합정도를 측정하는 용도혼합지표를 수도권지역 읍면동 단위의 인구수, 오피스 고용자 수, 상업 고용자수를 이용하여 주성분분석을 적용하였다. 또한 주택가격에 영향을 미치는 교통요인으로 지하철 접근성과 도로교통 접근성을 산출하고, 서울시 동별 복합용도개발지수와 지하철과 도로교통 접근성 변수와 더불어 주택수요, 지역성장율 등 사회경제변수들로 구성된 주택가격모형을 통하여 이들이 해당 동별 아파트 가격에 어떠한 영향을 주는가를 분석하였다. 분석 결과 복합용도개발과 교통이 주택가격에 영향을 준다는 뉴어바니즘의 개념이 확인되었다.

• 응용통계연구
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• 제28권2호
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• pp.289-294
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• 2015

생동성 시험과 같은 임상약리학분야의 연구는 일반적으로 한 개체 내에서 반복하여 측정된 자료구조를 사용하므로 선형혼합모형을 이용하여 분석하는 것이 보편적이다. 이러한 모형에서 랜덤효과는 개체 내 관측 자료 사이의 상관관계를 설명하고, 공분산행렬은 개체-내 변동을 설명한다. 생동성 분석은 두 약물의 약동학적 변수인 Cmax와 AUC의 기하평균비에 대한 90% 신뢰구간이 동등성 한계인 [0.8, 1.25] 범위에 드는지 알아보는 분석으로, 고정효과에는 시기, 순서군, 치료효과를, 랜덤효과에는 개체효과를 가지는 선형혼합모형을 이용하여 분석한다. 이러한 분석이 적용된 실제 예를 살펴보기 위하여 레보플록사신 연구의 자료를 활용하였다.

• 의학교육논단
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• 제18권2호
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• pp.106-113
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• 2016

The purpose of this study is to identify factors associated with effective peer-assisted learning (PAL) for nursing students. This review examined studies on PAL in nursing education. The literature was searched using terms including 'nursing & peer assisted learning,' 'nursing & peer learning,' and 'nursing & peer teaching.' Potentially relevant research on PAL was identified, and 12 studies were determined to meet the inclusion criteria. This review includes five qualitative, three mixed-methods, and three experimental studies published on the topic. In the studies reviewed, practicum classes were found to use PAL the most. Students of the same age were most commonly the subjects of PAL, as indicated in six papers. PAL has been suggested to affect participants' knowledge, self-efficacy, confidence, and anxiety. The findings indicate that interactions between peers promote learning and lead to mutually positive responses, which provide opportunities for self-development. Finally, students' learning outcomes improve and their confidence in their knowledge and skills increases as they experience the role of student nurse. These findings indicate that PAL can be utilized as an efficient learning method in nursing education programs. However, effective strategies for using PAL to achieve learning objectives and maximize learning outcomes are needed.

• Journal of Oral Medicine and Pain
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• 제46권4호
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• pp.143-149
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• 2021

Purpose: Oromandibular dystonia is a neurological disorder that affects the jaw and lower face muscles, often resulting in abnormal repetitive movement of the jaw and perioral structures. The purpose of this study was to assess the effectiveness of surface electromyography (EMG) in evaluating the treatment outcome of oromandibular dystonia. Methods: Based on a retrospective review of medical records, we analyzed the data of four patients who received medication or botulinum toxin injection, as well as surface EMG of the jaw muscles before and after treatment. We assessed the patients' clinical characteristics and the results of surface EMG before and after treatment. Results: The case series included one female and three males, and the age range was 65-78 years. Based on the clinical features, two subjects were classified as jaw deviation and the remaining two were as jaw closing. Dystonic patterns revealed by surface EMG varied, including phasic, tonic, and mixed contraction patterns. EMG amplitude after treatment was lower than pre-treatment value in all four subjects, suggesting improved clinical signs and symptoms. One subject who received clonazepam and another who received botulinum toxin injection showed a remarkable reduction in EMG amplitude within a normal range. Conclusions: Surface EMG can be used to effective evaluate treatment outcomes in patients with oromandibular dystonia. It could be considered as an adjunctive diagnostic tool in managing patients with dystonia.