• 한국신뢰성학회지:신뢰성응용연구
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• 제18권3호
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• pp.201-207
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• 2018

Purpose: To develop the reliability growth planning for a subsystem of guided weapon system using PM2-Continuous model. Methods: The target MTBF of the subsystem is set by allocating the system target MTBF to the lower level, where ARINC method is applied. Other model parameters such as initial MTBF, management strategy ratio and average fix effectiveness factor are chosen from historical growth parameter estimates. Given the values of model parameters, the reliability growth planning curve using PM2-Continuous model is constructed and the sensitivity analyses are performed for the changes of model parameters. Results: We have developed the reliability growth plan for a subsystem of guided weapon system using PM2-Continuous model. It was found that the smaller the ratio of initial MTBF to target MTBF, the smaller the management strategy ratio, the smaller the average fix effectiveness factor, and the shorter the development test period, the higher reliability growth is required. Conclusion: The result of this study will be used as a basis for establishing the reliability growth plan, the test period setting and the budget appropriation for the similar system entering the system development stage in the future.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1923-1927
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• 2012

Background: Studies investigating the association between 2R/3R polymorphisms in the thymidylate synthase 5'-untranslated enhanced region (TYMS 5'-UTR) and gastric cancer risk have generated conflicting results. Thus, a meta-analysis was performed to summarize the data on any association. Methods: Pubmed, Embase, and CNKI databases were searched for all available studies. The strength of association between TYMS 5'-UTR 2R/3R polymorphism and gastric cancer risk was estimated by odds ratios (ORs) with 95% confidence intervals (CIs). Results: Six individual case-control studies with a total of 1, 472 cases and 1, 895 controls were included into this meta-analysis. Analyses of total six relevant studies showed that there was no obvious association between the TYMS 5'-UTR 2R/3R polymorphism and gastric cancer risk. Subgroup analyses based on ethnicity showed 2R of TYMS 5'-UTR 2R/3R contributes to gastric cancer risk in the Asian population ($OR_{Homozygote\;model}$ = 1.71, 95%CI 1.19-2.46, P = 0.004; $OR_{Recessive\;genetic\;model}$ = 1.70, 95%CI 1.18-2.43, P = 0.004). However, the association in Caucasian populations was uncertain due to the limited studies. Conclusions: Our meta-analysis suggests that 2R of TYMS 5'-UTR 2R/3R contributes to gastric cancer risk in the Asian population, while this association in Caucasians populations needs further study.

• Asia Pacific Journal of Business Review
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• 제1권2호
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• pp.37-62
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• 2017

To analyze the effects of R&D expenditure on the firm value of Korean firms, we classified portfolios based on R&D activity levels. After that, we conducted a time-series analysis to assess excess returns from the portfolios. To carry out such an analysis, an empirical analysis of excess returns in the capital market was performed by using the monthly earning rate of stocks from 2000 to 2013. The purpose of this research is to provide basic data on investment to stakeholders in the capital market by analyzing the effects of R&D on the firm value and to overcome scholarly limitations by offering a new model of analysis. The criteria for classifying the portfolios were based on R&D expenditure levels. The analysis models follow the Fama-French Three-Factor Model and the Carhart Four-Factor Model. The analyses results are as follows. Extrapolating monthly profit rates based on R&D expenditure levels, portfolios with low R&D expenditures showed higher earning rates than those with high R&D expenditures. This suggests that high R&D expenditures did not translate into high earning rates. The investor depreciates the R&D expenditures related profitability and the possibility of success in the market, leading to falls in stock prices and a failure to give a positive effect on the firm value. Our research differs from the previous investigations as we carried out an empirical analysis based on the actual investors' attitudes about R&D expenditures and how these can generate excess earnings. Our research results show that the data related to R&D expenditure are not reflected fully in the market.

• 한국경영과학회지
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• 제16권2호
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• pp.61-61
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• 1991

We propose a strategic R&D resource allocation and project selection model based on national R&D policy and objectives. First, contributions to R&D policy and objectives for each R&D area are evaluated by using analytical hierarchy process (AHP). Second, fuzzy Delphi are proposed to estimate R&D budget for each R&D area. Then, a project selection grid is also introduced to implement two-phased evaluation for R&D project selection. We also discuss how to improve the consistency in AHP and how to reduce the pairwise comparison in AHP. The proposed model enables the decision makers to allocate R&D budget, and to evaluate and select the R&D proposals based on both the contribution to national R&D policy and objectives, and the size of each R&D area concurrently

• 경영과학
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• 제16권2호
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• pp.61-77
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• 1999

We propose a strategic R&D resource allocation and project selection model based on national R&D policy and objectives. First, contributions to R&D policy and objectives for each R&D area are evaluated by using analytical hierarchy process (AHP). Second, fuzzy Delphi are proposed to estimate R&D budget for each R&D area. Then, a project selection grid is also introduced to implement two-phased evaluation for R&D project selection. We also discuss how to improve the consistency in AHP and how to reduce the pairwise comparison in AHP. The proposed model enables the decision makers to allocate R&D budget, and to evaluate and select the R&D proposals based on both the contribution to national R&D policy and objectives, and the size of each R&D area concurrently.

• 대한임베디드공학회논문지
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• 제18권2호
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• pp.51-58
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• 2023

This paper proposes a deep learning method for estimating the heart rate from facial videos. Our proposed method estimates remote photoplethysmography (rPPG) signals to predict the heart rate. Although there have been proposed several methods for estimating rPPG signals, most previous methods can not be utilized in low-power single board computers due to their computational complexity. To address this problem, we construct a lightweight student model and employ a knowledge distillation technique to reduce the performance degradation of a deeper network model. The teacher model consists of 795k parameters, whereas the student model only contains 24k parameters, and therefore, the inference time was reduced with the factor of 10. By distilling the knowledge of the intermediate feature maps of the teacher model, we improved the accuracy of the student model for estimating the heart rate. Experiments were conducted on the UBFC-rPPG dataset to demonstrate the effectiveness of the proposed method. Moreover, we collected our own dataset to verify the accuracy and processing time of the proposed method on a real-world dataset. Experimental results on a NVIDIA Jetson Nano board demonstrate that our proposed method can infer the heart rate in real time with the mean absolute error of 2.5183 bpm.

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.894-898
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• 2009

In a post printing section of roll to roll printing systems, scratch problem is the major defects. The functional qualities such as conductivity, mobility could deteriorate because of the scratch defect. In general, the scratch of the printed pattern on the flexible substrate was induced from a contact between rolls and printed pattern in the post printing section. In this paper, for non-contacting transfer of a moving web, a mathematical tension model has been developed considering strain due to air floatation and the proposed mode has been validated by numerical simulation. Additionally, the correlation between floatation height and speed compensation to control the tension and register are investigated. On the basis of the proposed model, a guide line of speed control in R2R printing system is presented to guarantee the non-contact between rolls and R2R printed pattern on the flexible substrate.

• 농약과학회지
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• 제12권2호
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• pp.111-117
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• 2008

잿빛곰팡이균(Botrytis cinerea)에 대한 N-phenylbenzenesulfonamides 유도체(1-45)들의 살균활성에 관한 비교 분자장 분석(CoMFA)을 정량적으로 검토하였다. 통계적으로 CoMFA 모델의 예측성과 상관성이 비교분자 유사성 지수분석(CoMSIA) 모델보다 월등히 좋았다. 최적화 된 CoMFA I 모델의 통계값은 예측성이 $r^2_{cv.}(or\;q^2)=0.457$ 그리고 상관성이 $r^2_{ncv.}=0.959$이었고 살균활성은 기질 분자들의 입체장(51.9%)과 정전기장(35.6%)에 의존적이었다. 또한 progressive scrambling 분석으로 얻어진 섭동에 대한 감도($d_q^{2'}/dr^2_{yy'}=0.898$)와 예측성($q^2=0.346$ 및 SDEP=0.614)에 의하여 최적의 CoMFA I 모델은 우연 상관성에 의존적이지 않음을 알았다. 그러므로 CoMFA I 모델의 등고도 분석 결과로부터, N-phenyl 고리상 $R_3$ 및 $R_4$-치환기는 입체적으로 크고 $R_1$-치환기로서 S-phenyl 고리상 para-치환기는 입체적으로 작은 치환체가 살균활성에 기여 할 것으로 기대되었으며 최적화 된 CoMFA I 모델은 잿빛곰팡이균에 대한 살균활성을 예측하는데 유용하게 활용될 수 있을 것이다.

• 한국환경과학회지
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• 제14권12호
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• pp.1203-1209
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• 2005

Basic dyes, Rhodamine 6G(R6G), Rhodamine B(RB), and Methylene Blue(MB), dissolved in water were used to investigate single-component adsorption affinity to the pearl layer fractionated according to the size. Unfractionated pearl layers were also used as adsorbents for the R6G and RB. The Langmuir and the Redlich-Peterson(RP) models were used to fit the adsorption data, and the goodness of fit was examined by using determination coefficient($R^2$) and standard deviation(SSE). The 3-parameter RP model was found to be better in describing the dye adsorption data than the 2 parameter Langmuir model, as can be expected from the number of parameters involved in the model. The adsorption affinity to the fractionated pearl layer was higher than that to the unfractionated layer The affinity order to the fractionated Conchiolin layer was found to be R6G > MB > RB. Furthermore, the dye adsorption capacity of the various types of pearl layer was found to be in the order, the fractionated pearl > powdered pearl > unfractionated pearl, exhibiting different adsorption isotherms according to the types of layer used in the study.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.34-44
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• 2016

Background: Little is known about how chemical water quality is associated with ecological stream health in relation to landuse patterns in a watershed. We evaluated spatial characteristics of water quality characteristics and the ecological health of Dongjin-River basin, Korea in relation to regional landuse pattern. The ecological health was assessed by the multi-metric model of Index of Biological Integrity (IBI), and the water chemistry data were compared with values obtained from the health model. Results: Nutrient and organic matter pollution in Dongjin-River basin, Korea was influenced by land use pattern and the major point sources, so nutrients of TN and TP increased abruptly in Site 4 (Jeongeup Stream), which is directly influenced by wastewater treatment plants along with values of electric conductivity (EC), bacterial number, and sestonic chlorophyll-a. Similar results are shown in the downstream (S7) of Dongjin River. The degradation of chemical water quality in the downstream resulted in greater impairment of the ecological health, and these were also closely associated with the landuse pattern. Forest region had low nutrients (N, P), organic matter, and ionic content (as the EC), whereas urban and agricultural regions had opposite in the parameters. Linear regression analysis of the landuse (arable land; $A_L$) on chemicals indicated that values of $A_L$ had positive linear relations with TP ($R^2=0.643$, p < 0.01), TN ($R^2=0.502$, p < 0.05), BOD ($R^2=0.739$, p < 0.01), and suspended solids (SS; ($R^2=0.866$, p < 0.01), and a negative relation with TDN:TDP ratios ($R^2=0.719$, p < 0.01). Conclusions: Chemical factors were closely associated with land use pattern in the watershed, and these factors influenced the ecological health, based on the multimetric fish IBI model. Overall, the impairments of water chemistry and the ecological health in Dongjin-River basin were mainly attributes to point-sources and land-use patterns.