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A development in method of evaluating the measurement precisions using approximate F tests and variance components from expected mean square (EMS) is investigated. The research proposes three-factor mixed measurement models with the fixed and random factors. Unrestricted and unconstrained design work was rarely studied, while restricted and constrained designs have been significantly discussed. The unrestricted and unconstrained designs assume to be an independence of interaction. The proposed evaluation method about the measurement precisions can be extended to four-factor random measurement model or mixed measurement model. The study also presents the three evaluation indexes of precisions such as R&RTR (Reproducibility & Repeatability-To-Total Precision Ratio), PTR (Precision-To-Tolerance Ratio), and SNR (Signal-To-Noise Ratio). Numerical examples are proposed to evaluate the approximate F tests with Satterthwaite degrees of freedom and three indexes using the measurement precisions from EMS.

Purpose: Job satisfaction among blood center nurses is suboptimal due to challenging working conditions, characterized by unexpected tasks resulting from sudden schedule changes and frequent weekend shifts. This study aimed to quantitatively examine the relationships among job stress, psychological capital, personejob fit, job crafting, and job satisfaction, based on the job crafting model. Additionally, qualitative data were collected through mixed methods to gain a better understanding of the experiences related to job satisfaction among blood center nurses. Methods: A convergent mixed methods research design was employed to simultaneously collect quantitative and qualitative data and to integrate the findings from both analyses. A total of 127 full-time nurses who had completed at least a three-month probationary period at blood centers participated in the study. Participants were recruited from three blood centers operated by the Korean Red Cross in three metropolitan cities. The survey included open-ended qualitative questions and five quantitative measures covering job satisfaction, job stress, psychological capital, personejob fit, and job crafting. The data collection occurred from September to October 2022. Results: Regression analysis identified key factors influencing job satisfaction as personejob fit, job stress, psychological capital, and marital status, explaining 80% of the variance. Qualitative analysis of the open-ended responses showed five main themes: “deriving fulfillment from work,” “challenges encountered at work,” “driving forces behind positive outcomes,” “congruence between individual’s traits and job requirements,” and “efforts to perform meaningful work.” Conclusions: The findings suggest the need for developing an employee assistance program and educational initiatives aimed at enhancing job satisfaction among blood center nurses. These should focus on improving personejob fit, managing stress, aiding with emotional labor, and bolstering psychological capital.

본 연구는 폐기되는 자동차의 리버스물류 네트워크 구축을 위해 폐차수집센터(CC), 분해 및 해체센터(DC) 등의 최적위치와 경로를 결정하는데 활용할 수 있는 모델링을 제시하고자 한다. 폐기되는 자동차의 리싸이클링 네트워크를 구축하는데 따른 비용을 고려하여 리싸이클링 네트워크 구축을 위한 위치-경로문제에 대한 최적모델을 제안하였으며, 이러한 목적을 달성하기 위해 유전적 해법(algorithm)과 Tabu탐색해법을 결합한 혼합해법을 사용하였다. 제안된 모델은 청두의 X 기업에서 실행된 실제사례를 기반으로 수집센터, 분해 및 해체센터의 위치 결정뿐만 아니라 수집센터 혹은 분해 및 해체센터와 리싸리클링 사이트 간 비용 최소화 조건의 최적 경로설정을 제시하였다. 이러한 연구결과는 연구의 대상이 된 X기업에 적용하게 된다면 자동차의 라싸이클링 물류네트워크 구축을 위한 투자비용과 시간을 절감할 수 있을 뿐만 아니라 기업의 경쟁력을 제고효과도 있을 것이다. 아울러 다른 종류의 리버스 물류네트워크를 구축하는데 적용될 수 있을 것이다.

This paper presents modelling approach that could be used to establish one important part of end-of-life vehicles (ELVs) reverse logistics network by identifying optimum location for collection centers, dismantling centers and routing arrangement for vehicles. Considering the cost optimization in ELVs recycling logistics network, this paper suggests optimization model of ELVs recycling logistics network location-routing problem and use the algorithm which combine genetic algorithm and tabu search algorithm for solving the proposed model. The proposed model is validated by a real case performed in X company and determines the location of collection centers (CCs) and dismantling centers (DCs), as well as the route arrangement between CCs or DCs and recycling sites (RSs) in ELVs recycling logistics network of X company in Chengdu city of China. In the result, the investment cost and time in the X company could be diminished and the competitiveness of X company would be enhanced as well. Also, this proposed Model may be used to determines the location and routing of different kinds of facilities organized in a reverse recycling network.

이 연구에서 조건부와 무조건부 수익분포에서 발견되는 왜도와 첨도를 잡아내기 위해서 두 가지 종류의 시간 가변적인 이변량 혼합정규분포 GARCH 모형을 제시하고 있다. 이러한 모형들은 표본 외 헤지포트폴리오의 분산의 감소율과 Hansen (2001)의 SPA 검정 통계량을 이용하여 전통적인 이변량 GARCH 모형들과 비교분석하고 있다. 이 연구에서 고려하고 있는 모든 모형들은 시간가변적인 헤지비율을 추정하기 위해서 캐나다 달러와 UK 파운드에 적용하였다. 표본 외 헤지성과를 보기 위해서 1일부터 30일까지의 헤지기간에 대해서 추정모형의 헤지포트폴리오 분산을 비교하였다. 실증분석 결과는 비교적 단기의 헤지기간에 있어서는 전통적인 시간가변적인 모형이 다른 모형들에 비해서 통계적으로 우월한 것으로 나타났고, 헤지기간이 5일 이상으로 길어지면 시간가변적인 혼합 정규분포 모형이 5%의 유의수준에서 다른 모형들에 비해서 통계적으로 우월한 것으로 나타났다.

In this study, bivariate mixed normal time varying GARCH models are proposed to capture the skewness and kurtosis detected in both conditional and unconditional return distributions. They are compared with different standard bivariate GARCH models in terms of both the percentage variance reduction of the out-of-sample hedged portfolio and the statistical significance test of the performance improvements using Hansen’s (2001) SPA statistics. The models are applied to estimate time varying hedge ratios for the Canadian dollar and UK pound. The out-of-sample evaluation is carried out by comparing the hedged portfolio variances from all models over one to 30 days horizons. The empirical results demonstrate that the standard time varying model significantly outperforms the other competing models at shorter horizons. However, as the hedge horizon is extended to longer than 5 days, it is clearly evident that mixed normal GARCH models are the best at the usual significance level of 5%.

목적: 본 연구는 달맞이꽃종자유와 달맞이꽃종자유에 로즈마리오일을 첨가한 혼합오일의 아토피피부염에 대한 치료적 대 체물질로의 활용가능성을 탐색하기 위해 시행하였다. 방법: NC/Nga 생쥐를 대조군과 아토피피부염 유발군, 달맞이꽃종자 유 처치군 및 달맞이꽃종자유-로즈마리 혼합오일 처치군으로 나누어 항산화능과 지질과산화능을 분석하였다. 생검조직의 현미경 관찰과 IgE 분석, 비만세포(mast cell)의 탈과립 변화에 대한 조사를 하였다. 결과: 허브오일인 달맞이꽃종자유와 달맞이꽃종자유-로즈마리 혼합오일 처리시 전자공여능과 지질과산화능이 대조군 대비 모두에서 증가하였으며, 표피두께 는 모두 감소하였다. 광학현미경 관찰은 아토피피부염 유발군에서는 현저한 표피두께의 비후가 관찰되었으며 허브오일의 처리군에서는 아토피피부염 유발군에 비하여 두께가 감소하여 대조군과 비슷한 회복 양상을 보였다. IgE의 양적 측정 결과 아토피피부염 유발군은 증가를 나타내었으나, 허브오일 처리시는 감소를 나타냈다. 비만세포의 탈과립수는 허브오일 처리 시 아토피피부염 유발군 대비 감소하였다. 결론: 본 연구 결과는 피부염치료에 허브오일을 이용한 치료법으로 활용 가능성 을 확인하였으며, 두 종류 이상의 허브오일을 혼합사용 시 상승 효과가 있었다.

Purpose: This study aimed to explore the possibility of using evening primrose oil (E oil) and evening primrose–rosemary mixed oil (ER oil) as alternative substances for treating atopic dermatitis (AD). Methods: NC/Nga mice were divided into the control, AD-induced, E oil-treated, and ER oil-treated groups. Each group was treated for 6 days. Thereafter, the effects of anti-oxidation and lipid peroxidation activity (LPA) were analyzed. In addition, tissue biopsy samples were observed under a microscope, immunoglobulin E (IgE) levels were measured, and the effects of mast cell degranulation were assessed. Results: Compared with the control group, the E oil- and ER oil-treated groups showed increased electron donating activity (EDA) and LPA. The epidermal thicknesses were less in the E oil- and ER oil-treated groups than in the AD-induced group and recovered to a degree similar to that of the control group. Quantitative measurements showed decreased IgE levels in the E oiland ER oil-treated groups compared with those in the AD-induced group. Mast cell degranulation was reduced in the E oil- and ER oil-treated groups compared with that in the AD-induced group. Conclusion: The study results showed that herb oils such as E oil and ER oil can potentially be used for treating dermatitis and that oils with two or more herb oils improved the results.

目的: 本研究旨在探讨月见草油（evening primrose oil，E油）和月见草油-迷迭香混合油（evening primrose– rosemary mixed oil，ER油）作为治疗特应性皮炎的替代物质的可能性。方法: NC/Nga小鼠分为对照组、特应性 皮炎诱导组、E油组和ER油处理组。然后分析了抗氧化作用和脂质过氧化活性的影响。此外，在显微镜下，观察组 织活检标本，测定免疫球蛋白E（immunoglobulin E，IgE）水平，评估肥大细胞脱颗粒的影响。结果: 与对照组相 比，E油和ER油处理组均有增加供电子活性和脂质过氧化活性，以及其表皮厚度均减少。在显微镜观察下，特应性 皮炎诱导组的表皮厚度显著增加，而E油处理组和ER油处理组与特应性皮炎诱导组相比厚度减少，并恢复到与对照 组相似的程度。定量测量显示特应性皮炎诱导组的IgE水平增加，而E油组和ER油组的IgE水平下降。E油组和ER油 组与特应性皮炎诱导组相比，肥大细胞脱颗粒减少。结论: 研究结果表明，草药油如E油和ER油可能被用于治疗皮 炎，而使用两种或多种植物油的混合油可能提高疗效。

This study investigates the implementation of the Blended-Collaborative Writing Instructional (BCWI) model to enhance English as a Foreign Language (EFL) student teachers’ academic writing achievement. Academic writing is a critical skill for prospective educators, yet EFL learners often encounter challenges across the writing process, including idea generation, organization, revision, and editing. Employing a mixed-methods design, the study pursues three main objectives: (1) to examine whether the BCWI model improves student teachers’ overall academic writing achievement, (2) to analyse whether the model enhances individual writing elements such as content, organization, vocabulary, language use, and mechanics, and (3) to explore student teachers’ perceptions toward BCWI practices in academic writing classes. Findings reveal that the BCWI model significantly improves learners’ ability to generate and structure ideas, refine drafts through iterative feedback, and develop autonomy in managing the writing process. Moreover, the model optimizes instruction, fosters collaboration, enriches materials, and incorporates constructive feedback through blended learning environments. Nevertheless, challenges emerged, including communication issues, unequal workload distribution, irresponsible group behaviour, and varying levels of digital literacy. These findings underscore the pedagogical potential of BCWI while highlighting the need for further research to refine its application across diverse learner profiles and proficiency levels.

InnovVizwas designed and developed anew as avisualization and simulationtool to present innovation and strategy information. The InnovViz system employs two key types of technology, namely mixed reality (MR) and neural network (NN). An experiment was conducted to examine the usability, acceptance and possible adoption of this new system. Participants comprised 4 experts from 4 top performing entrepreneurial firms and 161 master degree students from 2 leading universities. The study used a modified UTAUT model and a cognition and perception model. The results revealed that when the InnovViz was introduced, the key drivers to adoption are Facilitating Conditions (FC) and Voluntary to Use (VOL). Adequate knowledge and sufficient resources were found to strongly affect FC construct. The expert"fs rating of a firm"fs innovation and performance was more congruent with senior students with a technology-background than with a finance and accounting-background. InnovViz was seen as providing complex information with an ease of use and usefulness for showing data and assessment. Among the three types of visuals depicted by InnovViz, experts rated their usefulness in descending order as follows: Cube, Tetrahedron and Saturn. Finally, experts found backward simulation to be slightly more useful for assessment than forward simulation.

Purpose: This study was conducted to determine factors influencing changes in the self-esteem of multicultural adolescents over time. Methods: A longitudinal design was adopted to analyze secondary data. This study used the 2nd, 4th, and 6th year data of Multicultural Adolescents Panel Study (MAPS) collected by the Korea Youth Policy Institute. The linear mixed model was utilized to analyze self-esteem changes over time. Results: The factors of sex and age of the students, the mother’s Korean writing ability, and the Filipino or Japanese mothers had a significant effect on the self-esteem change of multi-cultural adolescents over time. Specifically, it was found that female students’ self-esteem was decreased by 0.04 (t=-2.39, p=.017) more than male students over time. As the subject’s age and mother’s Korean writing ability increased, self-esteem was decreased by 0.01 (t=-2.53, p=.011) and 0.03 (t=-2.52, p=.012) over time. In addition, compared to that of those who had mothers from Korea, self-esteem of those who had Filipino or Japanese mothers was decreased by 0.04 significantly. Conclusion: Therefore, when developing a self-esteem promotion program, it is necessary to develop content by reflecting the characteristics of mothers as well as the gender and age of students. Furthermore, the significance of this study is in that it established a foundation for a positive self-identity of multicultural adolescents whose number is increasing recently by identifying factors affecting their self-esteem.

이 연구는 근로장애인의 빈곤 영향 요인들을 살펴보고, 근로장애인의 빈곤정책에 대한 함의를 제시하기 위해 한국장애인고용패널 1~4차 조사의 패널자료를 분석하였다. 본 연구는 이항 종속변수를 분석하고자 패널로짓 분석의 임의효과모델과 고정효과모델의 단점을 보완하고 장점을 활용할 수 있는 혼합 모델을 사용하였다. 분석 결과, 가구구성요소 중에서 아동유무와 노인유무는 개별사례간 및 개별사례내 효과가 모두 빈곤 가능성을 높이는 것으로 나타났다. 반면에 추가근로가구원과 개인근로소득은 개별사례간 효과와 개별사례내 효과 모두 빈곤의 가능성을 낮추는 요인으로 조사되었다. 사회복지급여 중에서 사회보험급여는 개별사례간 및 개별사례내 효과가 모두 근로장애인의 빈곤 가능성을 낮추었으나, 공공부조급여는 개별사례내 효과만 약간 빈곤 가능성을 낮추는 것으로 나타났다. 이에 따라 근로장애인가구의 빈곤 완화를 위해 돌봄서비스 제공, 양질의 일자리 제공 및 사회보험급여 확대를 제안하였다.

This study analyzed 4 waves(2008~2011) of the Panel Survey of Employment for the Disabled to explore factors on the poverty of disabled workers, and to suggest implications to policies for poor disabled workers. A poverty status of disabled workers is the dependent variable of this study, and a mixed model has been used to resolve the problems of both a random effect model and a fixed effect model in a panel logit. The result shows that both the between- and within-cluster effects of a child and an elderly are negative and statistically significant, while the between- and within-cluster effects of additional workers in a household are positive and statistically significant, i.e. reducing the odds of poverty. The between- and within-cluster effects of individual earned income by disabled workers are also positive and statistically significant on the poverty. The between- and within-cluster effects of pension benefits are positive and statistically significant, while the between-cluster effects of public assistance benefits are not significant, and the within-cluster effects of public assistance benefits are on the border line. Therefore, care services are needed to be provided with disabled workers with a child or an elderly in order to allow other family members to work. In addition, ‘good’ jobs are needed rather than just jobs for disabled workers. Finally, income support for disabled workers are needed to be extended.

본 연구는 한국과 미국의 응답자들이 평정척도 상의 중간보기 “?”를 서로 다르게 사용하는지에 대한 비교 문화적 검증을 실시하였다. 이를 위해 직무기술척도(Job Descriptive Index)에 대한 한국과 미국 집단(각각 932명)의 응답을 다집단 범주적 확인적 요인분석(Multi-Group Categorical Confirmatory Factor Analysis)과 혼합문항반응이론(Mixed-Model Item Response Theory)으로 분석하였다. 다집단 분석결과, 두 집단 간에 측정틀 동일성과 측정단위 동일성은 성립하였으나, 임계치 모수의 구조에서는 차이가 있는 것으로 나타났다. 혼합문항반응이론을 실시한 결과, 한국과 미국집단 모두에서 응답범주에 대한 반응양상이 다른 세 개의 하위 잠재집단이 존재하였다. 이 중 “?” 응답범주를 많이 선택하는 “?” 선호집단에 대한 보다 자세한 분석 결과, 미국 표본에서는 “?” 선호 집단의 비중이 매우 적고, 응답범주의 순차성 가정이 지지되지 않는 것으로 나타났다. 반면, 한국 표본에서는 “?” 선호집단이 다른 하위 잠재집단과 유사한 비중을 차지할 뿐만 아니라, “?”을 비교적 일정한 간격을 지니는 순차적 평정척도의 중간보기로 인식하는 것으로 나타났다. 본 연구의 결과를 바탕으로 중간보기 “?”의 사용에 대한 적용적 시사점 및 추후 연구 과제를 논의하였다.

The present study investigated differential use of the middle category “?” option between Korean and American workers using the 2009 version Job Descriptive Index(JDI). For this purpose, a multi-group categorical confirmatory factor analysis and a mixed-model item response theory(MM-IRT) analysis were conducted across a Korean worker sample and American normative sample (N=932 for each). The multi-group analysis result supported configural and metric invariance across the groups. However, the threshold structure was not invariant across the groups. The MM-IRT analysis identified three latent subgroups within both Korean and American samples. Overall, the Korean group has larger subgroup class size favoring the “?” option than the American group. An inspection of item parameters revealed the threshold locations of the mixed partial credit model were frequently disordered for the American group, but not for the Korean group. The implications of the results and future research issues were discussed.

본 논문은 반복측정 변량분석의 대안으로서 교차 무선효과를 가진 선형 혼합효과 모형을 소개한다. 두 종류의 선형 혼합효과 모형의 설정, 추정방법, 모형 비교방법, 추론방법에 관해 R패키지 중 하나인 lme4 패키지의 lmer 함수를 가지고 설명한다. 예제데이터를 통해 선형 혼합효과 모형의 용례를 보인다. 또한, 몬테카를로 시뮬레이션 실험을 통해 특정 상황에서 선형 혼합효과 모형과 변량분석 사이에서 가설검정 수행을 비교한다.

This paper introduces a linear mixed-effects model with crossed random effects as an alternative to repeated measures analysis of variance (RM-ANOVA). With lmer function in the lme4 package, one of the R packages, two kinds of the linear mixed-effects model are described regarding the model specification, an estimation method, model comparison criteria, and an inference method. The use of the linear mixed-effects model is illustrated through an empirical example data. The performance of hypothesis testing is compared via a Monte Carlo simulation study between the mixed-effects model and variance of analysis framework.

월별로 집행되는 통화정책과 달리 실물경제의 반응을 측정하는 대표변수인 GDP 는 분기별로 공표되고 있어 VAR 모형분석을 이용한 표준적 동태분석에 어려움이있다. 본고에서는 이러한 분기 GDP 및 월별 금융변수로 이루어진 혼합주기 자료를 가지고, 통화정책(통화량 변동을 대리변수로 사용)의 GDP에 대한 파급효과를월별 VAR 모형을 김윤영․박준용(2007) 등이 제시한 방법으로 추정 분석하였다. 붓스트랩을 이용한 충격반응분석 결과, 중위값(median) 기준으로 통화량 증가 충격은 2개월 이후의 GDP 증가에 큰 영향을 미치다가 그 효과가 점차 사라지지만분기 내에서 월별로 진동성(cyclicity) 을 갖는 것으로 나타났다. 반면 GDP 증가충격은 단시간에 물가와 환율을 상승시키나 시간의 흐름에 따라 점차 그 효과가작아지는 것으로 나타났다. 마지막으로 환율 상승 충격은 9개월 이후 GDP를 증가시켜 충격․반응 간 시차가 상대적으로 긴 것으로 나타났다. 그러나 분기모형의 경우 통화량 증가 충격이 GDP에 미치는 영향의 방향이 혼합주기 모형과 같으나 좀 더 평활화(smoothing) 된 형태로 나타났다. 이런 접근은 통화정책의 對GDP 동태효과를 월단위로 파악할 수 있어 금융시장이 단기간에 급변하는 위기시의 정책결정에 유용한 정보를 제공할 수 있을 것으로 판단된다.

Central banks conduct monetary policy on a monthly basis and have interests in the dynamic analysis of monthly frequency data. However, GDP is observed quarterly and thus an impulse response analysis using quarterly model is conventional. A realistic approach is to estimate a monthly VAR using a mixed frequency data. In this paper, following Kim and Park(2007), we conduct a dynamic analysis of the effect of Korean monetary policy on GDP under VAR model with a mixed frequency data. According to the impulse response analysis based on GMM estimation, we find the increase of money supply affects GDP growth and the effect disappears gradually. However, the inflation and Won/Dollar exchange rate are not much affected by the money supply shocks. This approach may be useful especially during financial crisis because the monetary policy effect is analyzed by monthly period.

본 연구는 한우의 도체형질들에 대한 유전적 변이를 분석방법에 따라 어떠한 차이가 있는지를 알아보고자 한우 후대검정자료를 이용하여 분석하였다. 분석에 이용된 도체성적 관련 자료는 가축개량사업소와 한우개량단지에서 1996년부터 2001년까지 태어난 후대검정우 1526두로부터 조사었다. 한우에 있어서 주요 개량형질인 육량과 육질에 영향하는 도체중, 도체율, 배최장근단면적, 등지방두께, 근내지방도를 대상으로 유전력과 유전상관을 추정하였다. 유전모수 추정에 있어서 REML 분석법과 Bayesian추론방법으로써 Gibbs Sampling 분석법을 사용하였는데 각각의 모수들에 대한 Gibbs Sampler는 100,000회 실시하였고 초기 1,000회는 모수의 사후분포에 대한 부정확성으로 간주하여 모수의 사후분포특성 규명에서 제외하였다. 각각의 형질들에 대한 유전변이는 이러한 두 가지 분석방법을 상호 비교 함으로써 최적의 통계분석방법을 모색하였다.도체형질에 대한 유전력 추정은 REML 방법을 통한 추정에서는 근내지방도가 0.51로 고도의 유전력을 보였고, 도체율이 0.25로 중도의 유전력이 추정되었다. Gibbs Sampling 방법을 통한 추정에서도 근내지방도가 0.54로 고도의 유전력을 도체율에서 0.25로 중도의 유전력을 보였다. REML 분석방법과 Gibbs Sampling 분석방법에서의 유전력은 다소 큰 차이는 보이지 않았으나, 대체로 Gibbs Sampling 방법으로 분석한 유전력 추정치가 높게 추정되었다.그리고, 유전상관분석에서는 REML 방법을 통한 분석에서 도체중과 배최장근단면적에서 0.651로 높은 정의 유전상관을 나타내었고, 배최장근단면적과 등지방두께에서 -0.139로 부의 유전상관을 나타내었다. Gibbs Sampling 방법에서는 도체중과 도체율, 배최장근단면적에서 각각 0.814, 0.695으로 높은 정의 상관을 나타내었고, 배최장근단면적과 등지방두께에서 -0.126으로 부의상관을 나타내었다. Gibbs Sampling 방법을 통한 분석에서 특정 형질간 유전상관이 높게 나타났으며, 다소 큰 차이를 보이지 않았다.REML 분석방법과 Bayesian Inference를 바탕으로 한 Gibbs Sampling 분석에서 모수 추정은 큰 차이를 보이지 않았다. 따라서 방대한 현장정보를 활용하여 보다 정확한 모수 추정을 수행하기 위해서는 분석모형에 대한 계수행렬의 역행렬 계산을 통한 REML 방법의 한계성을 극복할 수 있는 방법으로써 Gibbs Sampling 분석 방법이 가능할 것으로 사료된다.

The aims of this study were to estimate genetic parameters for carcass traits on Hanwoo(Korean Native Cattle) and to compare two different statistical algorithms for estimating genetic parameters. Data obtained from 1526 steers at Hanwoo Improvement Center and Hanwoo Improvement Complex Area from 1996 to 2001 were used for the analyses. The carcass traits considered in these studies were carcass weight, dressing percent, eye muscle area, backfat thickness, and marbling score. Estimated genetic parameters using EM-REML algorithm were compared to those by Bayesian inference via Gibbs Sampling to find out statistical properties. The estimated heritabilities of carcass traits by REML method were 0.28, 0.25, 0.35, 0.39 and 0.51, respectively and those by Gibbs Sampling method were 0.29, 0.25, 0.40, 0.42 and 0.54, respectively. This estimates were not significantly different, even though the estimated heritabilities by Gibbs Sampling method were higher than ones by REML method.Since the estimated statistics by REML method and Gibbs Sampling method were not significantly different in this study, it is inferred that both mothods could be efficiently applied for the analysis of carcass traits of cattle. However, further studies are demanded to define an optimal statistical method for handling large scale performance data.

심리학 실험자료 분석을 위한 선형 혼합효과 모형에서 실험자료의 특성에 따라서 모형설정 방법이 실험조건의 효과를 탐지하는데 미치는 영향을 몬테카를로 시뮬레이션 방법을 통해 조 사하였다. 구체적으로 자료생성모형의 무선효과의 복잡성을 변화시키면서 모형을 선택하는 전략에 따른 1종 오류비율과 검정력을 비교하였다. 그 결과, 최대모형 접근(또는 무선기울기 모형)은 자료의 무선효과 구조가 단순한 조건에서 실험조건 효과를 지나치게 엄격하게 검증 하여 상대적으로 낮은 검정력을 보였다. 반면, 모형비교 접근을 사용했을 때는 본 연구의 모 든 시뮬레이션 조건에서 1종 오류비율이 유의수준에 근접하면서도 최대모형 접근에서보다 우 수하거나 그에 상당하는 검정력을 나타냈다. 실험 연구자가 선형 혼합효과 모형을 분석도구 로 사용할 때 고려해야 할 점을 논의하였다.

In a linear mixed-effects model for psychological experimental data analysis, the effect of the model selection procedure on detecting the experimental condition effect was investigated through a Monte Carlo simulation study. Specifically, while changing the complexity of the random effect structure of the data-generating model, the type I error rate and power were compared between the model selection strategies. As a result, the maximal model approach (or the random slope model) showed relatively low statistical power under the condition that the structure of the random component of the data was simple. On the other hand, when the model comparison approach was used, the Type I error rate approached the significance level, and the power was superior to or equivalent to that of the maximal model approach in all simulation conditions of this study. Finally, we discussed the points that experimental researchers should consider when using the linear mixed-effects model as an analysis tool.

This paper is concerned with the integrated problem of line balancing and model sequencing in mixed model assembly lines(MMALBS), which is important to efficient utilization of the lines. In the problem, we deal with the objective of minimizing the overall line length To apply the GAs to MMALBS problems, we suggest a GA representation which suitable for its problems, an efficient decoding technique for the objective, and genetic operators which produce feasible offsprings. Extensive experiments are carried out to analyze the performance of the proposed algorithm. The computational results show that our algorithm is promising in solution quality.