• 식품기술
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• 제26권3호
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• pp.258-265
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• 2013

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.89-96
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• 2023

Uric acid produced by guanine deaminase (GDA) is involved in photoaging and hyperpigmentation. Reactive oxygen species (ROS) generated by uric acid plays a role in photoaging. However, the mechanism by which uric acid stimulates melanogenesis in GDA-overexpressing keratinocytes is unclear. Keratinocyte-derived paracrine factors have been identified as important mechanisms of ultraviolet-induced melanogenesis. Therefore, the role of paracrine melanogenic growth factors in GDA-induced hypermelanosis mediated by uric acid was examined. The relationships between ROS and these growth factors were examined. Primary cultured normal keratinocytes overexpressed with wild type or mutant GDA and those treated with xanthine or uric acid in the presence or absence of allopurinol, H₂O₂, or N-acetylcysteine (NAC) were used in this study. Intracellular and extracellular bFGF and SCF levels were increased in keratinocytes by wild type, but not by loss-of-function mutants of GDA overexpression. Culture supernatants from GDA-overexpressing keratinocytes stimulated melanogenesis, which was restored by anti-bFGF and anti-SCF antibodies. Allopurinol treatment reduced the expression levels of bFGF and SCF in both GDA-overexpressing and normal keratinocytes exposed to exogenous xanthine; the exogenous uric acid increased their expression levels. H₂O₂-stimulated tyrosinase expression and melanogenesis were restored by NAC pretreatment. However, H₂O₂ or NAC did not upregulate or downregulate bFGF or SCF, respectively. Overall, uric acid could be involved in melanogenesis induced by GDA overexpression in keratinocytes via bFGF and SCF upregulation not via ROS generation.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.39-44
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• 2014

Glass discs functionalized with alkynyl (GDA) terminated monolayers were prepared and incubated in $AgNO_3$ solution (GDA-Ag). The modified functional glass surfaces were characterized by X-ray photoelectron microscopy (XPS). The potential of GDA and GDA-Ag as antimicrobial surfaces was investigated. Anti-microbial efficacies of GDA against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, and Candida albicans was relatively low ranging from 4.67 to 17.00%. However, the GDA-Ag was very effective and its antimicrobial efficacy ranged from 99.90 to 99.99% against the same set of microbial strains except for C. albicans where it was 95.50%. The durability of the Ag bonded to the terminal alkynyl groups was studied by placing the GDA-Ag in PBS buffer solution (pH 7.4) for two weeks. Initially, the silver release was relatively fast, with 40.05 ppb of silver released in first 24 h followed by a very slow and constant release. To study the potential of GDA-Ag for medical applications, in vitro cytotoxicity of GDA-Ag against Human Embryonic Kidney 293 (HEK293) cell lines was studied using WST-assay. The cytotoxicity of the GDA-Ag was very low (5%) and was almost comparable to the control (blank glass disc) indicating that GDA-Ag has a promising potential for medical applications.

• 건축사
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• 통권480호
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• pp.36-41
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• 2009

• 건축사
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• 통권645호
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• pp.38-43
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• 2023

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.646-652
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• 2010

This paper investigates a method to improve the breakdown voltage characteristics of a gas discharge arrester (GDA) for a surge suppressor. The middle electrode is inserted between two terminal electrodes. Voltage application to the electrode synchronized and amplified by the impulse voltage decreases spark overvoltage from 45% to 57.6%. The decrease is caused by higher voltage slope, as opposed to applied impulse voltage (by 5.5 to 6.2 times). In addition, the GDA model using ATP-Draw was used to analyze the operation characteristics of GDAs. The test and simulation results agree to within 2% when the trigger source was used.

• 한국지역사회생활과학회지
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• 제24권3호
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• pp.327-342
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• 2013

The purposes of this study were to explore consumer preference for the types of nutrition label of cereal products and to identify some influencing factors on purchase intention and choice probability of nutrition-labeled products. First, most of the respondents preferred the nutrition fact panel with traffic light-GDA(TL-GDA), while the nutrition fact panel only type and the nutrition fact panel with front-of-package(FOP) type were preferred by few respondents. However, consumers evaluated higher for TL-GDA type and FOP symbol type, while the nutrition fact panel only type was evaluated much lower. Second, consumer preference for label types was partially related with 'eating breakfast' and consumer evaluations of the types of labels for the nutrition fact panel only and the nutrition fact panel with FOP were found to be significantly different by gender. Lastly, both purchase intention and choice probability for nutrition-labeled products were found to be significantly influenced by information search and product attitude. In addition, choice probability was found to be significantly influenced by individual characteristics such as gender and grade. It is necessary to find the relationship between nutrition labels and consumer response as this can help consumers make a better choice of food as well as providing some useful information on consumers to the related parties such as companies and consumer organizations.

• 한국정보통신학회논문지
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• 제22권1호
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• pp.125-130
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• 2018

선형판별분석(LDA) 기법은 특징벡터의 차원을 줄이거나 클래스 식별에 이용되는 통계적 분석 방법이다. 그러나 선형 분리가 불가능한 데이터 집합의 경우에는 비선형 함수를 이용하여 특징벡터를 고차원의 공간으로 사상(mapping) 시켜줌으로써 선형 분리가 가능하도록 만들 수 있는데, 이러한 기법을 일반화된 판별분석(GDA) 또는 커널판별분석(KDA) 기법이라고 한다. 본 연구에서는 인터넷에 공개되어 있는 능동소나 표적신호에 LDA 및 GDA 기법을 이용하여 표적식별 실험을 수행하고, 그 결과를 비교/분석하였다. 실험 결과 104개의 테스트 데이터에 대해 LDA 기법으로는 73.08% 인식률을 얻었으나 GDA 기법으로는 95.19%로 기존의 MLP 또는 커널 기반 SVM에 비해 나은 성능을 보였다.

• 한국지리정보학회지
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• 제22권4호
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• pp.39-58
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• 2019

본 연구에서는 GPM 위성자료 및 분포형 강우-유출 모형 KIMSTORM2(KIneMatic wave STOrm Runoff Model2)을 이용하여 용담댐 유역(930㎢)을 대상으로 유출모의를 수행하였다. 모형의 유출해석은 2014년 08월 25일 05:00~17:00, 2017년 09월 11일 01:00~12:00, 2018년 06월 26일 23:00~06월 27일 10:00 총 3개의 집중호우 기간으로, 4가지 공간자료: (a) 7개의 지상관측소 강우를 Kriging 기법으로 공간내삽한 자료, (b) 원 GPM 자료, (c) 조건부합성(Conditional Merging, CM)으로 보정한 GPM(CM-GPM) 자료, (d) 지리적편차(Geographical Differential Analysis, GDA)로 보정한 GPM(GDA-GPM) 자료를 각각 준비하였다. 유출 보정은 유역내 3개의 수위관측지점(천천, 동향, 용담댐)을 대상으로 실시하였으며, 4가지 공간자료에 대하여 모형의 매개변수인 초기 토양수분량, 하천 Manning 조도계수, 유효투수계수를 각각 보정하였다. 보정결과는 결정계수(Determination coefficient, R²), Nash-Sutcliffe의 모형효율계수(NSE) 및 유출용적지수(Volume Conservation Index, VCI)를 산정하였다. 그 결과, 3개의 강우에 대한 Kriging, GPM, CM-GPM 및 GDA-GPM의 평균 NSE는 0.94, 0.90, 0.94, 0.94, R2는 0.96, 0.92, 0.97, 0.96, VCI는 1.03, 1.01, 1.03, 1.02로 보정되었다. R², NSE 및 VCI에 있어, CM-GPM과 GDA-GPM이 원 GPM보다 첨두유출량 및 유출용적에 있어 보다 잘 보정되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1390-1403
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• 2016

Facial expression recognition (FER) plays a very significant role in computer vision, pattern recognition, and image processing applications such as human computer interaction as it provides sufficient information about emotions of people. For video-based facial expression recognition, depth cameras can be better candidates over RGB cameras as a person's face cannot be easily recognized from distance-based depth videos hence depth cameras also resolve some privacy issues that can arise using RGB faces. A good FER system is very much reliant on the extraction of robust features as well as recognition engine. In this work, an efficient novel approach is proposed to recognize some facial expressions from time-sequential depth videos. First of all, efficient Local Binary Pattern (LBP) features are obtained from the time-sequential depth faces that are further classified by Generalized Discriminant Analysis (GDA) to make the features more robust and finally, the LBP-GDA features are fed into Hidden Markov Models (HMMs) to train and recognize different facial expressions successfully. The depth information-based proposed facial expression recognition approach is compared to the conventional approaches such as Principal Component Analysis (PCA), Independent Component Analysis (ICA), and Linear Discriminant Analysis (LDA) where the proposed one outperforms others by obtaining better recognition rates.