• Nuclear Engineering and Technology
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• 제53권1호
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• pp.304-313
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• 2021

Nickel base Alloy X-750, which is used as fastener parts in light-water reactor (LWR), has experienced many failures by environmentally assisted cracking (EAC). In order to improve the reliability of passive components for nuclear power plants (NPP's), it is necessary to study the failure mechanism and to predict crack growth behavior by developing a probabilistic failure model. In this study, The Bayesian inference was employed to reduce the uncertainties contained in EAC modeling parameters that have been established from experiments with Alloy X-750. Corrosion fatigue crack growth rate model (FCGR) was developed by fitting into Paris' Law of measured data from the several fatigue tests conducted either in constant load or constant ΔK mode. These parameters characterizing the corrosion fatigue crack growth behavior of X-750 were successfully updated to reduce the uncertainty in the model by using the Bayesian inference method. It is demonstrated that probabilistic failure models for passive components can be developed by updating a laboratory model with field-inspection data, when crack growth rates (CGRs) are low and multiple inspections can be made prior to the component failure.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.115-121
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• 2019

Response surface methodology (RSM) is used to investigate the complex coupling effects of different operating parameters on silicon growth rate in planetary CVD reactor. Based on the computational fluid dynamics (CFD) model, an accurate RSM model is obtained to predict the growth rate with different parameters, including temperature, pressure, rotation speed of the wafer, and the mole fraction of dichlorosilane (DCS). Analysis of variance is used to estimate the contributions of process parameters and their interactions. Among the four operating parameters that have been studied, the influences of susceptor temperature and the operating pressure were the most significant factors that affect silicon growth rate, followed by the mole fraction of DCS. The influence of wafer rotation is the least. The validation tests show that the results of silicon deposition rate obtained from the regression model are in good agreement with those from CFD model and the maximum deviations is 2.15%.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.53-56
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• 2007

Computer simulation of microstructure evolution during hot forging process is of great interest in recent years. Recrystallization model and grain growth model which use a phenomenological approach were summarized. For the waspaloy, upsetting process and cogging process were simulated using $DEFORM^{TM}$ and the change in grain size were investigated in each deformation procedure.

• STI Policy Review
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• 제1권2호
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• pp.51-68
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• 2010

This paper compares OECD nations by developing a comprehensive evaluation index that examines the efforts and achievements of countries toward Low-Carbon Green Growth. The input-process-output of a Low-Carbon Society system is in dynamic competition with that of a High-Carbon Society system. The model used in this study of the comprehensive evaluation index for Low-Carbon Green Growth was comprised of Large indices such as Input, Process, and Output. The Input and Output consisted of 'Social-economic' and 'Physical-ecological' Middle indices while the Process was made up of 'Stimulation mechanisms' and 'Participation of stakeholders and Knowledge flow' Middle indices. In order to calculate the comprehensive evaluation index, our model gave a weight to each indicator/index and applied a weighted arithmetic mean. Korea ranked $15^{th}$ out of 30 OECD nations in the comprehensive evaluation that analyzed Input ($14^{th}$), Process ($18^{th}$), and Output ($17^{th}$). The top five nations were Switzerland, Sweden, Denmark, Germany, and France; while Japan was $8^{th}$ and the USA $26^{th}$.

• 유통과학연구
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• 제12권4호
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• pp.65-72
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• 2014

Purpose - Because of the emphasis on the necessity of academic-industrial cooperation between companies and universities, there are various ongoing academic-industrial cooperation programs led by the government. As government actively supports such cooperation as policy,and universities vitalize new technology development, academic-industrial cooperation between companies and universities is being recognized as an important growth engine for companies the competitiveness of academic-industrial cooperation is also attracting more interest. The government has vitalized human resource fostering, practical R&D, and technology transfer to companies since 2012 by executing a "leading university fostering project for academic-industrial cooperation." Based on an organic interlink among universities, industry, and research institutes, the government also created and is promoting several models of such cooperation between companies and universities to support shared growth of industry and local universities. The purpose of academic-industrial cooperation is growth and benefit fromtechnology development, technical cooperation, and technology transfer between companies and universities. Research design, data, and methodology - As more academic-industrial cooperation efforts are ledby companies due to the limitation in technology-focused commercialization cooperation, the academic-industrial cooperation system became fragmented and it is losing the potential for future advancement. Specifically, as differences between universities grow, academic-industrial cooperation between companies and universities based on new technology from universities is finding difficulty advancing,while systematic support from companies to enhance the performance of businesses created by academic-industrial cooperation is also insufficient. Accordingly, this study established a growth model for the advancement of academic-industrial cooperation between companies and universities and suggested a plan to strengthen the competitiveness and promote the future advancementof academic-industrial cooperation between companies and universities by analyzing the current situation of such cooperation and diagnosing its issues. Results - This study explored the concept and current status of academic-industrial cooperation relationships and analyzed related issues. For such cooperative organizations to be competitive, the employment environment of professional human resources for academic-industrial cooperation should be improved and measures to secure professional resources should be taken as early as possible. Though the academic-industrial cooperation now is being led by government, there is a limitation based on business models, which require creation of profit; however, an academic-industrial cooperation model still cannot stand alone without the support of government. This study also pointed out that a having only a plan to build competitiveness of companies and universities for academic-industrial cooperation is not sufficient. Conclusions - In order to increase the competitiveness of academic-industrial cooperation, a detailed growth-sharing model for academic-industrial cooperation should be developed, and there should be more joint development processes for the advancement of such cooperation in which the need for technology development can be verified in advance. In addition, beyond focusing on technology-focused academic-industrial cooperation, a network between companies and universities searching for ideas for academic-industrial cooperation in the fields of human and social aspects should be created. A new academic-industrial model linking current cooperation between companies and universities to the local area should be built based on such academic-industrial cooperation in human and social fields.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.718-726
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• 2009

The objective of this study was to develop and validate secondary models that can predict growth parameters of L. monocytogenes Scott A as a function of concentrations (0-3%) of a commercial potassium lactate (PL) and sodium diacetate (SDA) mixture, pH (5.5-7.0), and temperature (4-37DC). A total of 120 growth curves were fitted to the Baranyi primary model that directly estimates lag time (LT) and specific growth rate (SGR). The effects of the variables on L. monocytogenes Scott A growth kinetics were modeled by response surface analysis using quadratic and cubic polynomial models of the natural logarithm transformation of both LT and SGR. Model performance was evaluated with dependent data and independent data using the prediction bias ($B_f$) and accuracy factors ($A_f$) as well as the acceptable prediction zone method [percentage of relative errors (%RE)]. Comparison of predicted versus observed values of SGR indicated that the cubic model fits better than the quadratic model, particularly at 4 and $10^{\circ}C$. The $B_f$and $A_f$for independent SGR were 1.00 and 1.08 for the cubic model and 1.08 and 1.16 for the quadratic model, respectively. For cubic and quadratic models, the %REs for the independent SGR data were 92.6 and 85.7, respectively. Both quadratic and cubic polynomial models for SGR and LT provided acceptable predictions of L. monocytogenes Scott A growth in the matrix of conditions described in the present study. Model performance can be more accurately evaluated with $B_f$and $A_f$and % RE together.

• 한국산학기술학회논문지
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• 제12권5호
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• pp.2067-2077
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• 2011

최근 IT, BT, NT를 중심으로 기술간 융합이 가속화 되고, 다양한 기술이 복합적으로 활용되는 산업분야가 증가하면서 기술간 경쟁관계 분석에 대한 전략적, 정책적 필요성이 커지고 있으나 기술간 동태적 관계를 분석한 연구는 그리 많지 않다. 본 연구는 기술경쟁 관점에서 기술혁신 과정을 다룬다. 특히, 최근 정부가 우리 경제의 새로운 성장 비전으로 발표한 3대 분야 17개 신성장 동력 기술을 대상으로 하여 이들 기술들의 공진화 과정을 분석 한다. 분석을 위해서 대표적 기술혁신 자료인 특허정보를 활용하고, 동태적 경쟁확산모형으로 폭넓게 활용되고 있는 Lotka-Volterra 모형을 적용한다. 연구결과는 기술혁신 과정에 있어 3대 분야 간, 17개 신성장 동력 기술 간, 신성장 기술 내 세부기술 간 동태적 관계를 분석함으로써, 효과적인 국내 기술정책 수립과 연구개발 우선순위 선정 등의 전략적 의사결정에 활용할 수 있을 것으로 기대된다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.305-312
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• 2016

Purpose: The purpose of this study is to provide a sensitivity analysis of system reliability for recognizing effectiveness of changing of BD mode failures using reliability growth projection model based on NHPP. Methods: Crow extended reliability projection model (CERPM) is used to analyze the changing of two factors 1) the number of BD mode failures, 2) fix effectiveness factor (FEF) values. Results: The system reliability has increased in accordance with the number of BD mode failures and FEF values have increased. Conclusion: It is necessary to design failure modes and FEF values to supervise the reliability.

• 기술혁신연구
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• 제10권2호
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• pp.91-105
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• 2002

This paper extends the empirical analysis on R&D based growth model so that the nonstationary panel unit root testing methods can be used to distinguish the exogenous growth model and R&D based growth model for the 1981-1999 period with fourteen OECD economies including Korea. Our results show that first, using U.S. and Group mean as benchmarking, the stochastic R&D productivity convergence to benchmarking is not supported in our data set. Second, the empirical results for stochastic nonconvergence to the U.S. or group mean also are robustness to panel unit root methods. We, therefore, find strong support for the implications for R&D based growth model.

• Molecular & Cellular Toxicology
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• 제3권3호
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• pp.159-164
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• 2007

Stimulation of epidermal growth factor receptor (EGFR) is essential in signaling pathway of tumor cells. Thus, EGFR has intensely studied as an anticancer target. We developed hologram quantitative structure activity relationship (HQSAR) models for data set which consists of tricyclic azepine derivatives showing inhibitory activities for EGFR. The optimal HQSAR model was generated with fragment size of 6 to 7 while differentiating fragments having different atom and connectivity. The model showed cross-validated $q^2$ value of 0.61 and non-cross-validated $r^2$ value of 0.93. When the model was validated with an external set excluding one outlier, it gave predictive $r^2$ value of 0.43. The contribution maps generated from this model were used to interpret the atomic contribution of each atom to the overall inhibition activity. This can be used to find more efficient EGFR inhibitors.