• 한국압력기기공학회 논문집
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• 제17권1호
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• pp.36-48
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• 2021

As the material aging of nuclear power plants has been progressing in domestic and overseas, crack growth becomes one of the most important issues. In this respect, the crack growth assessment has been considered an essential part of structural integrity. The crack growth assessment for nuclear power plants has been generally performed based on ASME B&PV Code, Sec. XI but the idealization of crack shape and the conservative solutions of stress intensity factor (SIF) are used. Although finite element analysis (FEA) based on iterative crack growth analysis is considered as an alternative method to simulate crack growth, there are yet no guidelines to model the crack-tip spider-web mesh for such analysis. In this study, effects of various meshing factors on FE SIF calculation are systematically examined. Based on FEA results, proper criteria for spider-web mesh in crack-tip are suggested. The validation of SIF calculation method through mapping initial stress field is investigated to consider initial residual stress on crack growth. The iterative crack-tip modeling program to simulate crack growth is developed using the proposed criteria for spider-web mesh design. The SIF results from the developed program are validated by comparing with those from technical reports of other institutes.

• 한국보육지원학회지
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• 제16권1호
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• pp.115-143
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• 2020

Objective: The purpose of this study was to examine underlying types of developmental trajectories of adaptation to child care among infants and toddlers. This study also aimed to identify latent classes in their child care adaptation types in order to find predictors that account for individual differences. Methods: Participants were 420 mothers of infants and toddlers and 123 teachers. The levels of child care adaptation of participating infants and toddlers were rated monthly from early April to June, 2019. The collected data were analyzed using growth mixture modeling, latent class analysis and multinominal logistic analysis. Results: The results of growth trajectories of child care adaptation showed there were two to four latent groups by dimension of child care adaptation. Also, the groups of individual dimensions of child care adaptation were classified into three latent classes, which were 'complying and positive group', 'negative group', and 'individualized group. Multinominal logistic analysis revealed that children's age, gender, and temperament differentiated the three latent classes of adaptation to child care. Conclusion/Implications: The results show individual characteristics that infants and toddlers possess should be prudently considered in order for successful adaptation to child care.

• 한국프랜차이즈경영연구
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• 제13권4호
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• pp.1-12
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• 2022

Purpose: In 2020, the franchise industry accomplished a significant growth compared to the previous year, as the number of franchise companies increased by 9.0% while the number of franchise brands increased by 12.5%. Despite growth in size, the Korean franchise industry underwent many negative incidents, such as franchise ownership sales to private equity funds, that led to deterioration of businesses. From this point of view, this study aims to make various proposals to help policy makers develop franchise industry policies by analyzing trends of the current and previous presidential administrations' franchise policies and regulations using newspaper articles. Research design, data and methodology: A total of 7,439 articles registered in Naver API from February 25, 2013 to November 29, 2021 were extracted. Among them, 34 unrelated video articles were deleted, and a total of 7,405 articles from both administrations were used for analysis. The R package was used for word frequency analysis, word clouding, word correlation analysis, and LDA (Latent Dirichlet Allocation) topic modeling. Results: The keyword frequency analysis shows that the most frequently mentioned keywords during the previous administration include 'no-brand', 'major company', 'bill', 'business field', and 'SMEs', and those mentioned during the current administration include 'industry' and 'policy'. As a result of LDA topic modeling, 9 topics such as 'global startups' and 'job creation' from the previous administration, and 10 topics such as 'franchise business' and 'distribution industry' from the current administration were derived. The results of LDAvis showed that the previous administration operated a policy based on mutual growth of large and small businesses rather than hostile regulations in the franchise business, whereas the current administration extended the regulation related to franchise business to the employment sector. Conclusions: The analysis of past two administrations' franchise policy, it can be suggested that franchisors and franchisees may complement each other in developing the Fair Transactions in Franchise Business Act and achieving balanced growth. Moreover, political support is needed for sound development of franchisors. Limitations and future research suggestions are presented at the end of this study.

• 한국산업정보학회논문지
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• 제3권1호
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• pp.67-77
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• 1998

Reliability growth testing used to evaluate reliability in the automobile industry have not always been able to correctly address reliability concerns with increased confidence. The demand to confirm to all product performance requirements under various operating environments has added to the complexity of accurately assessin theproduct's reliability in the required development time. In addition, it is often desired to determine the relationship of a product's reliability to cost, development time, design, manufacturability and assembly. This paper presents the methods for reliability growth modeling to evaluate and interpret reliability concerns to support the reliability analysis of automobile assemblies and systems. This reliability growth modeling process is a mechanism to help "build in" reliability during early phases in the vehicle devleopment stage.

• 한국융합학회논문지
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• 제10권2호
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• pp.217-225
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• 2019

대표적인 종단자료 분석방법인 잠재성장모형(Latent Growth Modeling)은 무조건적 모형과 조건적 모형으로 구분한다. 잠재성장모형의 무조건적 모형 성장궤적은 선형으로 가정하여 분석하는 경우가 많다. 본 연구는 선형 성장궤적으로 가정하여 모형 적합도가 미달하는 경우 연관규칙기법을 이용하여 모형 적합도를 제고하는 방법론을 제안한다. 방법론은 연관규칙 마이닝의 순차패턴(Sequential Pattern)을 사용한다. 이를 위하여 종단자료를 분위별로 나누고, 각 분위에 속한 종단자료의 기간 변화를 산출한 뒤 이를 순차 패턴 화하였다. SPSS AMOS를 이용하여 한국고용정보원의 2001년부터 6년간 조사한 청년 패널 자료로 효과성을 검증하였다. 기존 단순선형함수를 가정할 때와 비교하여 모형 적합도가 상승하는 것을 확인할 수 있었다.

• 한국프랜차이즈경영연구
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• 제12권4호
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• pp.13-23
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• 2021

Purpose: This study aimed to derive clues for the franchise industry to overcome difficulties such as various legal regulations and social responsibility demands and to continuously develop by analyzing the research trends related to franchises published in Korea. Research design, data and methodology: As a result of searching for 'franchise' in ScienceON, abstracts were collected from papers published in domestic academic journals from 1994 to June 2021. Keywords were extracted from the abstracts of 1,110 valid papers, and after preprocessing, keyword analysis, TF-IDF analysis, and topic modeling using LDA algorithm, along with trend analysis of the top 20 words in TF-IDF by year group was carried out using the R-package. Results: As a result of keyword analysis, it was found that businesses and brands were the subjects of research related to franchises, and interest in service and satisfaction was considerable, and food and coffee were prominently studied as industries. As a result of TF-IDF calculation, it was found that brand, satisfaction, franchisor, and coffee were ranked at the top. As a result of LDA-based topic modeling, a total of 12 topics including "growth strategy" were derived and visualized with LDAvis. On the other hand, the areas of Topic 1 (growth strategy) and Topic 9 (organizational culture), Topic 4 (consumption experience) and Topic 6 (contribution and loyalty), Topic 7 (brand image) and Topic 10 (commercial area) overlap significantly. Finally, the trend analysis results for the top 20 keywords with high TF-IDF showed that 10 keywords such as quality, brand, food, and trust would be more utilized overall. Conclusions: Through the results of this study, the direction of interest in the franchise industry was confirmed, and it was found that it was necessary to find a clue for continuous growth through research in more diverse fields. And it was also considered an important finding to suggest a technique that can supplement the problems of topic trend analysis. Therefore, the results of this study show that researchers will gain significant insights from the perspectives related to the selection of research topics, and practitioners from the perspectives related to future franchise changes.

• 아동학회지
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• 제30권4호
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• pp.69-85
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• 2009

The purpose of this study was to identify developmental trajectories of externalizing problems in preschoolers and to investigate dimensions of temperament and parental behaviors associated with trajectory groups. Subjects were 180 3- to 5-year-old preschoolers (96 males, 84 females) in the metropolitan area of Seoul. They were assessed three times at 5 month intervals over a one year period. Teachers reported on children's behavior problems, and parents reported on children's temperaments. Latent Growth Curve Modeling Analysis with cohort sequential design revealed externalizing behaviors gradually decreased between 3 and 6. At the 6-year-old level externalizing behaviors were associated with high novelty seeking temperament. The results were discussed in terms of the importance of longitudinal research in developmental psychopathology.

• 아동학회지
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• 제31권3호
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• pp.83-97
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• 2010

Growth mixture modeling was used to identify types of changes in overt aggression from Grades 4 to 7 among a sample from the Korean Youth Panel Survey. Three discrete patterns were found to adequately explain changes of overt aggression in both boys and girls : Persistent intermediate aggression; Increasing aggression; and Decreasing aggression. Most boys (93%) fell into the Persistent intermediate aggression group and 49% of girls were found to fall into the Increasing aggression group. This suggests that prevention programs should recognize that girls are at risk of increasing aggression in their early adolescence. Multinomial logistic regression analysis shows that self-control, child abuse, peer support, and involvement with deviant peers at Grades 4 were all strongly associated with trajectory class membership. These associations did not differ by gender. These findings suggest that prevention programs should focus on the multiple risk factors of both boys and girls.

• 디지털융복합연구
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• 제16권6호
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• pp.85-93
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• 2018

대표적인 종단자료 분석방법인 잠재성장모형(Latent Growth Modeling)은 무조건적 모델과 조건적 모델로 구분되는데, 이중 무조건적 모델은 초기값과 기울기를 추정하여 적합도가 높은 모델을 추정해야 한다. 그렇지만 기존 잠재성장모형에는 종단자료의 형태가 단순선형함수 등 특정 함수가 아닐 경우 기울기를 추정하는 체계적인 방법론이 없었다. 본 연구에서는 뮤조건적 모델의 기울기를 추정하는데 연관규칙(Association Rule Mining)의 순차패턴(Sequential Pattern)을 사용하였다. 데이터는 한국고용정보원의 2001년~2006년에 조사한 청년 패널 데이터를 사용하였다. 제안한 방법론은 기존 단순선형함수를 가정할 때와 비교하여 적합도가 상승하는 것을 확인할 수 있었으며, 기울기 추정 과정을 시각화할 수 있는 부수적인 장점이 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.33-36
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• 2004

The process modeling for the growth rate in pulsed laser deposition(PLD)-grown ZnO thin films is investigated using neural networks(NNets) and the process recipes is optimized via genetic algorithms(GAs). D-optimal design is carried out and the growth rate is characterized by NNets based on the back-propagation(BP) algorithm. GAs is then used to search the desired recipes for the desired growth rate. The statistical analysis is used to verify the fitness of the nonlinear process model. This process modeling and optimization algorithms can explain the characteristics of the desired responses varying with process conditions.