• 생물환경조절학회지
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• 제32권4호
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• pp.501-512
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• 2023

사과 '후지' 만개일의 예측을 위해 전국적으로 활용이 가능한 모델을 선발하기 위해 우리나라에서 사용된 사례가 있는 대표적인 모델 4종을 평가하였다. 이를 위해 우리나라 사과 주산지 6곳(포천, 화성, 거창, 청송, 군위, 충주)의 사과원에서 3년간 관측된 기온과 만개일을 수집하여 각 모델에 적용하고 모델의 예측력을 평가 하였다. 냉각량 추정을 위한 Dynamic(DM) 모델과 가온량 추정을 위한 Growing Degree Days(GDH) 모델을 순차적으로 결합한 모델이 예측력이 가장 좋았으며, Chill Days(CD) 모델의 예측력이 가장 낮았다. Development Rate Model 1(DVR1)은 화성 지역과 같이 일 최저기온이 높고 상대적으로 일 최고기온이 낮아 일교차가 작은 지역에서는 실측일보다 빠르게 예측되는 과소추정오차를 보였다. 따라서 단일 모델로 우리나라 전국적인 사과 '후지' 만개일 예측을 위해서는 휴면타파에 필요한 냉각량 산정을 위한 DM 모델과 휴면타파 이후 개화에 필요한 고온량 산정을 위한 GDH 모델이 결합된 DM+GDH 모델이 가장 효과적일 것으로 판단된다. 그러나 보다 광범위한 지역의 장기간의 자료 수집과 이를 이용한 평가가 필요하다.

• 한국식품영양학회지
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• 제32권6호
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• pp.738-744
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• 2019

Recently, the prevalence of hyperlipidemia has been increasing, and consequently, the need to identify safe and effective treatments to control this chronic disease has also increased. The beneficial effects of probiotics have been revealed by several studies over the past few years, including their effects on hypertriglyceridemia. However, the mechanisms of action of probiotics are still unclear. The anti-obesity effects of Lactobacillus plantarum Q180 on lipid accumulation have already been demonstrated using an in vitro HepG2 cell model, and therefore, we investigated its efficacy and mechanism of action. Lipid accumulation was induced in HepG2 cells by palmitic acid treatment and then the cells were incubated with L. plantarum Q180 lysate or supernatant to investigate changes in lipid accumulation and expression of lipid metabolism-related genes. The results showed that the L. plantarum Q180-treated group exhibited significantly lower levels of lipid accumulation and mRNA expression of lipid synthesis- and adipogenesis-related genes than the palmitic acid-treated group did. These results indicate that L. plantarum Q180 may contribute to alleviating hypertriglyceridemia by inhibiting lipid synthesis.

• 한국광학회지
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• 제14권3호
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• pp.215-218
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• 2003

2R 광/전/광 파장변환기는 이미 검증된 기술을 사용하여 간단히 구현할 수 있으며 데이터 전송율을 제한하지 않는다는 장점이 있다. 그러나, 이 방식은 각 파장변환기를 통과하면서 타이밍 지터 성분이 계속 누적되어 cascadability가 제한된다 본 논문에서는 통상적인 정현파 신호 모델 대신 보다 현실적인 비선형 신호 모델을 제안하여 시스템 성능에 미치는 타이밍 지터의 영향 및 2R 광/전/광 파장변환기의 cascadability를 이론적으로 분석하였으며, 40-km re-circulation loop 실험 장치에서 10 Gb/s 신호에 대한 cascadability를 측정하여 계산 결과와 비교하였다.

• 대한기계학회논문집A
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• 제20권4호
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• pp.1241-1250
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• 1996

The characteristics of fatigue cumulative damage and fatigue life of 8-harness satin woven CFRP composites with a circular hole under constant amplitude and 2-level block loading are estimated by Stochastic Makov chain model. It is found in this study that the fatigue damage accumulation behavior is very random and the fatigue damage is accumulated as two regions under constant amplitude fatigue loading. In constant amplitude fatigue loading the predicted mean number of cycles to a specified damage state by Markov chain model shows a good agreement with the test result. The predicted distribution of the fatigue cumulative damage by Markov chain model is similar to the test result. The fatigue life predictions under 2-level block loading by Markov chain model revised are good fitted to the test result more than by 2-parameter Weibull distribution function using percent failure rule.

• 한국의류학회지
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• 제29권9_10호
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• pp.1285-1294
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• 2005

This study was fulfilled in the purpose of proposing construction strategies of Internet shopping-mall through the analysis of consumer moving line in Internet shopping-mall. This study was executed in two stages: theoretical study, qualitative study. In the theoretical study, hypothetical Internet shopping behavior model were constructed. Five internet shopping behavior types of apparel : purchase, searching purchase, prepurchase deliberation, information accumulation, opinion leadership and recreation were constructed. Next, consumer decision process were extracted from previous studies and a hypothetical internet shopping behavior model was constructed on the base of consumer decision process and Internet shopping behavior types. And then, through the qualitative study, Internet shopping behavior types were identified and hypothetical model was confirmed after adjustment. For qualitative study, 30 subjects were sampled by focus sampling and investigated by in-depth interview and observation. Seven internet shopping behavior types of apparel were found by the qualitative study: cautious purchase by price comparison, searching purchase, special low price purchase, impulse purchase, prepurchase deliberation, information accumulation and recreation-oriented. On the base of these behavior types, Internet shopping behavior model was adjusted and completed. Finally, according to the results of this study, Internet shopping construction methods that made customer's loyalty high and marketing strategy of Internet shopping-mall were proposed.

• 한국환경과학회지
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• 제14권9호
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• pp.835-842
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• 2005

The three-dimensional eco-hydrodynamic model was applied to estimate the physical process in terms of COD (chemical oxygen demand) and net supply(or decomposition) rate of COD in Kamak Bay to find proper management plan for oxygen demanding organic matters. The estimation results of the physical process in terms of COD showed that transportation of COD is dominant in surface level while accumulation of COD is dominant in bottom level. In the case of surface level, the net supply rate of COD was 0 -0.50 mg/m2/day. The net decomposition rate of COD was 0 -0.04 mg/m2/day in middle level(3 -6m) and 0.05 -0.1 5 mg/m2/day in bottom level(6m -bottom). These results indicates that the biological decomposition and physical accumulation of COD are occurred predominantly at the northern part of bottom level. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters in the region.

• Structural Engineering and Mechanics
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• 제66권2호
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• pp.151-160
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• 2018

With the aim to evaluate the fatigue damage accumulation and predict the residual life of engineering components under variable amplitude loadings, this paper proposed a new strain energy-based damage accumulation model by considering both effects of mean stress and load interaction on fatigue life in a low cycle fatigue (LCF) regime. Moreover, an integrated procedure is elaborated for facilitating its application based on S-N curve and loading conditions. Eight experimental datasets of aluminum alloys and steels are utilized for model validation and comparison. Through comparing experimental results with model predictions by the proposed, Miner's rule, damaged stress model (DSM) and damaged energy model (DEM), results show that the proposed one provides more accurate predictions than others, which can be extended for further application under multi-level stress loadings.

• Structural Engineering and Mechanics
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• 제44권6호
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• pp.753-762
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• 2012

The ratcheting characteristics of cylindrical shell under cyclic axial loading are investigated. The specimens are subjected to stress-controlled cycling with non-zero mean stress, which causes the accumulation of plastic strain or ratcheting behavior in continuous cycles. Also, cylindrical shell shows softening behavior under symmetric axial strain-controlled loading and due to the localized buckling, which occurs in the compressive stress-strain curve of the shell; it has more residual plastic strain in comparison to the tensile stress-strain hysteresis curve. The numerical analysis was carried out by ABAQUS software using hardening models. The nonlinear isotropic/kinematic hardening model accurately simulates the ratcheting behavior of shell. Although hardening models are incapable of simulating the softening behavior of the shell, this model analyzes the softening behavior well. Moreover, the model calculates the residual plastic strain close to the experimental data. Experimental tests were performed using an INSTRON 8802 servo-hydraulic machine. Simulations show good agreement between numerical and experimental results. The results reveal that the rate of plastic strain accumulation increases for the first few cycles and then reduces in the subsequent cycles. This reduction is more rapid for numerical results in comparison to experiments.

• 정보교육학회논문지
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• 제25권5호
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• pp.665-672
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• 2021

21세기 인류는 AI 실용 시대를 열어 가고 있다. 이제껏 인류는 산업 구조가 고도화 되어도 지식 생산의 추상화 작업 만큼은 자신의 고유 영역이라 보았는 데 그 믿음에 의구심을 갖게 되었고, 이에 현대인은 인간과 기계 지능을 구분하고 자신의 정체성을 새롭게 구축해야 하는 상황에 놓이게 되었다. 이에 본 논문은 현대 인류의 정체성을 과거로부터 축적한 지식의 결과라는 관점에서 살피고자 하였다. 이러한 논의를 지구와 인류 출현으로부터 시작하는 "단계별 지식 축적 방식의 변화" 라는 역사 모형으로 요약하여 제시하였다. 이 분석 모형의 1 단계는 지구 상에 인간 지능 출현까지의 "DNA 지식 축적" 이다. 2단계는 스스로 지식을 생산할 수 있게 된 인간의 생물학적 지능에 의한 "문명 지식 축적" 과정이다. 현재는 3단계로 분류되며 AI 기술을 이용한 "기계적 지식 축적"단계로 진입하고 있다고 보았다. 본 논문은 인류 역사를 이러한 단계별 지식 축적 모형으로 제안하며 관련한 논의를 기술하였다.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.821-831
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• 2006

Unicellular green algae of the genus Haematococcus have been studied extensively as model organisms for secondary carotenoid accumulation. Upon environmental stress, such as strong irradiance or nitrogen deficiency, unicellular green algae of the genus Haematococcus accumulate secondary carotenoids in vesicles in the cytosol. Because secondary carotenoid accumulation occurs only upon specific environmental stimuli, there is speculation about the regulation of the biosynthetic pathway specific for secondary carotenogenesis. Because the carotenoid biosynthesis pathway is located both in the chloroplast and the cytosol, communication between both cellular compartments must be considered. Recently, the induction and regulation of astaxanthin biosynthesis in microalgae received considerable attention because of the increasing use of this secondary carotenoid as a source of pigmentation for fish aquaculture, as a component in cancer prevention, and as a free-radical quencher. This review summarizes the biosynthesis and regulation of the pathway, as well as the biotechnology of astaxanthin production in Haematococcus.