• Journal of Mechanical Science and Technology
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• 제19권7호
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• pp.1393-1404
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• 2005

Fatigue crack growth and life have been estimated based on established empirical equations. In this paper, an alternative method using artificial neural network (ANN) -based model developed to predict fatigue damages simultaneously. To learn and generalize the ANN, fatigue crack growth rate and life data were built up using in-plane bending fatigue test results. Single fracture mechanical parameter or nondestructive parameter can't predict fatigue damage accurately but multiple fracture mechanical parameters or nondestructive parameters can. Existing fatigue damage modeling used this merit but limited real-time damage monitoring. Therefore, this study shows fatigue damage model using backpropagation neural networks on the basis of X -ray half breadth ratio B / $B_o$, fractal dimension $D_f$ and fracture mechanical parameters can estimate fatigue crack growth rate da/ dN and cycle ratio N / $N_f$ at the same time within engineering limit error ($5\%$).

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.29-33
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• 1998

Transport phenomena paly an inmportant role in bulk crystal growth processes. During crystal growth, the control of the growth front and the dopant concentration is crucial to crystal quality. The growth feasibility in thus determined by the heat transfer controlling the interface convexity and by the mass transfer controlling the constitutional supercooling. Through numerical modeling, a thorough understanding of the growth processes is possible, which in turn is a key to process improvenment. In this paper, we will summarize some work dine in my laboratory, both numerical and experimental, to illustrate the importance of understanding the transport phenomena during crystal growth processes.

• Human Ecology Research
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• 제55권3호
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• pp.263-274
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• 2017

The purposes of this study were to verify the longitudinal mediating effects of work-family balance on the relationship of role recognition in the family, marital intimacy and job satisfaction of married women, and to introduce longitudinal mediating effects by using latent growth curve modeling and autoregressive cross-lagged modeling. The subjects were married women from the third year data of the Korean Longitudinal Survey of Women and Family. Structural equational models were conducted with Amos ver. 21.0. The major findings are as follows. First, the result of the longitudinal mediating effects of latent growth modeling is the rate of change of work-family balance mediated between the rate of change of role recognition in the family and the rate of change of job satisfaction, and the rate of change of work-family balance mediated between the rate of change of marital intimacy and the rate of change of job satisfaction. Second, when using the autoregressive cross-lagged modeling, the more role recognition and marital intimacy of third year were the more work-family balance of fourth year, job satisfaction of fifth year. In both models, work-family balance mediated between role recognition in the family, marital intimacy and job satisfaction. Therefore, through this study, mediating effects of work-family balance can be found that there was a longitudinal effects.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권5호
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• pp.382-385
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• 2000

A mathematical model was developed, based on the time dependent changes of the specific growth rate, for prediction of the typical microbial cell growth in batch cultures. This model could predict both the lag growth phase and the stationary growth phase of batch cultures, and it was tested with the batch growth of Trichoderma reesei and Lactobacillus delbrueckii.

• KSBB Journal
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• 제14권1호
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• pp.45-50
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• 1999

본 연구에서는 석유의 탈황에 이용될 수 있는 미생물인 Desuljovrvbrio sp. B5의 생육특성을 조사하였다. Postgate medium C에서의 생육 최적 온도는 $38^{\circ}C$,pH는 6.6~7.0으로 나타났다. Corn steep liquer를 대체 배지성분으로 사용한 결과 0.79g/L의 균체를 얻을 수 있었으며 이는 기존의 결과와 비교하여 약 1.8배 증가한 값이다. Postgate medium C에서 Lactate의 대사 과정에서 생성되는 acctate는 10g/L 이상에서 성장저해를 유발하였다. $H_2S$는 10mM의 total sulfide 농도에서도 균체성장이 저해되었지만 이는 질소가스 주입으로 해소할 수 있었다. 또한 회분식 배양의 결과와 $H_2S$에 의한 product ingixtion에 근거한 균체성장의 modeling 결과는 잘 일치하였다.

• 한국결정성장학회지
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• 제22권1호
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• pp.42-50
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• 2012

Mural Art는 빛의 색채 반응과 몰입, 확산 작용을 통하여 다양한 이미지를 나타내게 할 수 있는 디자인 작업이다. 본 논문은 천연 보석의 광학 현상을 Mural Art에 적합한 Digital Pattern으로 형성하고, 보석 및 광물의 광채와 작품 디자인과의 연관성에 대하여 고찰하였다. 작품 디자인의 상호(관련) 작용에 나타난 새로운 가능성을 광채가 아름다운 울트라 마린(Ultramarine)과 스펙트럼(Spectrum)의 색채 예술로서 벽면에 기초하여, 고해상도 Image의 그래픽 디자인으로 표현하고, 지속가능한(3D) Simulation의 Interior(Presentation) Modeling으로 활용하여 보았다.

• 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.

• 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.

• Advances in nano research
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• 제3권3호
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• pp.143-168
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• 2015

Initiation of crack and its growth simulation requires accurate model of traction - separation law. Accurate modeling of traction-separation law remains always a great challenge. Atomistic simulations based prediction has great potential in arriving at accurate traction-separation law. The present paper is aimed at establishing a method to address the above problem. A method for traction-separation law prediction via utilizing atomistic simulations data has been proposed. In this direction, firstly, a simpler approach of common neighbor analysis (CNA) for the prediction of crack growth has been proposed and results have been compared with previously used approach of threshold potential energy. Next, a scheme for prediction of crack speed has been demonstrated based on the stable crack growth criteria. Also, an algorithm has been proposed that utilizes a variable relaxation time period for the computation of crack growth, accurate stress behavior, and traction-separation atomistic law. An understanding has been established for the generation of smoother traction-separation law (including the effect of free surface) from a huge amount of raw atomistic data. A new curve fit has also been proposed for predicting traction-separation data generated from the molecular dynamics simulations. The proposed traction-separation law has also been compared with the polynomial and exponential model used earlier for the prediction of traction-separation law for the bulk materials.

• Journal of Welding and Joining
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• 제20권5호
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• pp.78-86
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• 2002

A metallurgical model for the prediction of prior austenite grain size considering the dissolution kinetics of M$_3$C precipitates at the heat affected zone of SA508-cl.3 was proposed. The isothermal kinetics of grain growth and dissolution were respectively described by well-known equation, $dD/dT=M({\Delta}F_{eff})^M$ and Whelan's analytical model. The isothermal grain growth experiments were carried out for measure the kinetic parameters of grain growth. The precipitates of the base metal and the specimens exposed to thermal cycle were examined by TEM-carbon extraction replica method. The model was assessed by the comparison of BUE simulation experiments and showed good consistencies. However, there was no difference between the model considering and ignoring $M_3C$ precipitates. It seems considered that pinning force exerted by $M_3C$ Precipitates was lower than driving force for grain growth due to large size and small fraction of precipitates, and mobility of grain boundary was low in the lower temperature range.