• Geomechanics and Engineering
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• 제13권1호
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• pp.141-159
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• 2017

A pick cutter is a rock-cutting tool used in partial-face excavation machines such as roadheaders, and its quality is a key element influencing the excavation performance and efficiency of such machines. In this study, pick cutters with hardfacing deposits applied to a tungsten carbide insert were made with aim of increasing their durability and wear resistance. They were field-tested by being installed in a roadheader and compared with conventional pick cutters under the same excavation conditions for 24 hours. The hardfaced pick cutters showed much smaller weight loss after excavation, and therefore better excavation performance, than the conventional pick cutters. In particular, the damage to and detachment (loss) of tungsten carbide inserts was minimal in the hardfaced pick cutters. A detailed inspection using scanning electron microscope-energy dispersive X-ray spectrometry and three-dimensional X-ray computed tomography scanning revealed no macro- or micro-cracks in the pick cutters. The reason for the absence of cracks may be that the heads of pick cutters are mechanically worn after the tungsten carbide inserts have been worn and damaged. However, scanning revealed the presence of voids between tungsten carbide inserts and pick cutter heads. This discovery of voids indicates the need to improve production processes in order to guarantee a higher quality of pick cutters.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.121-121
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• 2003

The standard protocol for the production of transgenic mouse from ES-injected embryo has to process via chimera producing and several times breeding steps, In contrast, tetraploid-ES cell complementation method allows the immediate generation of targeted murine mutants from genetically modified ES cell clones. The advantage of this advanced technique is a simple and efficient without chimeric intermediates. Recently, this method has been significantly improved through the discovery that ES cells derived from hybrid strains support the development of viable ES mice more efficiently than inbred ES cells do. Therefore, the objective of this study was to generate transgenic mice overexpressing human resistin gene by using tetrapioid-ES cell complementation method. Human resistin gene was amplified from human fetal liver cDNA library by PCR and cloned into pCR 2.1 TOPO T-vector and constructed in pCMV-Tag4C vector. Human resistin mammalian expression plasmid was transfected into D3-GL ES cells by lipofectamine 2000, and then after 8~10 days of transfection, the human resistin-expressing cells were selected with G418. In order to produce tetraploid embryos, blastomeres of diploid embryos at the two-cell stage were fused with two times of electric pulse using 60 V 30 $\mu$sec. (fusion rate : 93.5%) and cultured upto the blastocyst stage (development rate : 94.6%). The 15~20 previously G418-selected ES cells were injected into tetraploid blastocysts, and then transferred into the uterus of E2.5d pseudopregnant recipient mice. To investigate the gestation progress, two El9.5d fetus were recovered by Casarean section and one fetus was confirmed to contain human resistin gene by genomic DNA-PCR. Therefore, this finding demonstrates that tetraploid-ES mouse technology can be considered as a useful tool to produce transgenic mouse for the rapid analysis of gene function in vivo.

• 천문학회보
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• 제38권2호
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• pp.45.1-45.1
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• 2013

Type Ia supernovae (SNe Ia) are a powerful tool to investigate the expansion history of the universe, because their peak luminosity is as bright as a galaxy and is known as an excellent standard candle. Since the discovery of the acceleration of the universe based on the observations of SNe Ia, higher than ever accuracy of their peak luminosity is needed to investigate various problems in cosmology. We started a project to improve the accuracy of the calibration of the peak luminosity of SNe Ia by measuring accurate distances to nearby resolved galaxies that host SNe Ia. We derive accurate distances to the SN Ia host galaxies using the method to measure the luminosity of the tip of the red giant branch (TRGB). In this study we present the results for M66 and M96 in the Leo I Group which are nearby spiral galaxies hosting SN 1989B and SN 1998bu, respectively. We obtain VI photometry of resolved stars in these galaxies from F555W and F814W images in the Hubble Space Telescope archive. We derive the distances to these galaxies from the luminosity of the TRGB. With these results we derive absolute maximum magnitudes of two SNe (SN 1989B in M66 and SN 1998bu in M96). We derive a value of the Hubble constant from the optical magnitudes of these SNe Ia and SN 2011fe in M101 based on our TRGB analysis. This value is similar to the values derived from recent estimates from WMAP9 and Planck results, but smaller than other recent determinations based on Cepheid calibration for SNe Ia luminosity.

• 한국산업정보학회논문지
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• 제20권1호
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• pp.9-18
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• 2015

로봇을 이용한 교육은 학생들에게 고차원의 사고, 창의적 표현, 발견 학습의 기회를 제공하고 있다. 또한 로봇을 통해 다양한 교과 영역을 가르칠 수 있으므로 STEAM 교육에도 적합한 도구라 볼 수 있다. 따라서 본 연구에서는 로봇을 이용한 STEAM 교육 콘텐츠를 설계하고 개발하였다. 초등학교 교과서를 분석하여 과학, 기술, 공학, 예술, 수학에서 로봇을 통해 효과적으로 전달 가능한 내용들을 추출하여 융합 콘텐츠를 설계하였다. 설계한 내용을 바탕으로 로봇을 조립하고, 프로그램하여 콘텐츠를 개발하였다. 개발된 콘텐츠를 초등학교 방과 후 수업에 직접 적용하였고, 수업 후 설문조사를 통해 교과목의 이해도와 흥미도, 참여도를 평가하였다. 연구결과 로봇을 활용한 STEAM 콘텐츠 수업에서 교과내용의 이해도와 흥미도, 참여도가 높게 나타났다. 이를 통해 STEAM 교육에 로봇의 활용이 교육적 효과가 있다는 점과 개별 교과지식보다 STEAM기반의 융합형 콘텐츠를 이용한 교육의 효과가 높다는 점을 확인할 수 있었다.

• Genomics & Informatics
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• 제5권4호
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• pp.143-151
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• 2007

To understand the mechanism of transcriptional regulation, it is essential to detect promoters and regulatory elements. Various kinds of methods have been introduced to improve the prediction accuracy of regulatory elements. Since there are few experimentally validated regulatory elements, previous studies have used criteria based solely on the level of scores over background sequences. However, selecting the detection criteria for different prediction methods is not feasible. Here, we studied the calibration of thresholds to improve regulatory element prediction. We predicted a regulatory element using MATCH, which is a powerful tool for transcription factor binding site (TFBS) detection. To increase the prediction accuracy, we used a regulatory potential (RP) score measuring the similarity of patterns in alignments to those in known regulatory regions. Next, we calibrated the thresholds to find relevant scores, increasing the true positives while decreasing possible false positives. By applying various thresholds, we compared predicted regulatory elements with validated regulatory elements from the Open Regulatory Annotation (ORegAnno) database. The predicted regulators by the selected threshold were validated through enrichment analysis of muscle-specific gene sets from the Tissue-Specific Transcripts and Genes (T-STAG) database. We found 14 known muscle-specific regulators with a less than a 5% false discovery rate (FDR) in a single TFBS analysis, as well as known transcription factor combinations in our combinatorial TFBS analysis.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2004년도 춘계학술발표대회 논문집
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• pp.156-160
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• 2004

Our time is called as the era of information-oriented society and up-to-date scientific technology, but it can be also called as the era of image. It is because the image has much influence upon our everyday life. In the deluge of images, the delivery of image Is a better and faster synergic tool than the delivery of language, and this trend is consistent with the phases of the times in which the analog modality of synergy is converted into the digital one. The image is a picture that is formed by a physical process, and is all the figures reflected by electronic equipments that reproduce the image. After the discovery of photograph in 1893, the image has been appeared first with the form of movie, and then with the form of TV. However, the appearance of such unidirectional synergic tools as movies and TV. has provided artists with some creative motives with which they intercommunicate their messages via some experimental bidirectional synergic tools. Among image-media arts, the performance of installation and participation is an important example that causes many changes through conceptional conversion, such as the conception of the time in space and formative characteristics. What satisfy this trend have been videos, lasers, holographic, and etc. Furthermore, the appearance of computer has provided a synesthesia, that is, a virtual reality, and mixed a real image with a visional one. The image-media art will realize better synergy through combining brand new machines, informational technology, and art, and have much influence upon our everyday life formatively and artistically in the future. with this study, through analyzing the meaning of relationship between image equipments and space.

• 경영정보학연구
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• 제10권2호
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• pp.195-209
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• 2008

고객의 니즈가 시시각각 변화하는 경영환경에서 획일화된 매장관리 방법으로 매장의 수익성을 증대시키기에는 한계가 있다. 따라서 고객의 선호 변화를 예측하여 각 매장에 적절한 상품을 추천할 필요가 있다. 본 연구에서는 판매 데이터 분석을 통해 시간 순서를 고려한 상품 추천 및 매장관리 방법을 제안한다. 즉 자기조직화지도(Self Organizing Map) 알고리즘을 이용하여 매장의 판매 프로파일을 군집화하고, 매장 궤적의 예측을 통해 목표 매장을 관리하는 방법을 제시한다. 본 연구의 방법론을 검증하기 위해 (주)더페이스샵 판매데이터를 적용하여 평가하였으며, 평가결과 제시한 방법론은 화장품처럼 유행에 민감하고 라이프사이클이 짧은 특징을 지닌 상품을 판매하는 매장의 수익성 증대에 기여할 수 있을 것으로 기대된다.

• 한국콘텐츠학회논문지
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• 제17권10호
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• pp.463-471
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• 2017

이야기콘텐츠 창작 시 작동하는 무의식의 세계가 있다. 작가도 모르는 심연의 무의식 층은 전 인류가 연결되어있기 때문에 작가자신도 모르게 공통의 이야기를 만드는 길로 간다. 이렇게 만들어진 이야기가 원형신화고 오늘날 중요저작도구로 사용되고 있다. 이 원형신화가 발견되기 전에 제작된 무성영화 '달세계 여행'의 구조를 분석하면 여전히 원형의 틀을 찾을 수 있다. 이 영화는 동시대 네 작품으로부터 받은 영감을 작가가 직관적 상상으로 제작한 것임에도 원형의 틀이 완벽하게 드러났다. 이점은 신화의 원형이 지역이나 시간과 상관없이 관계하고 있는 것이다. 짧은 시간에 창작된 이야기가 오랜 시간 전승해온 신화와 같은 구조를 가지고 있는 이유는 인간의 집단 무의식속에 이야기의 원형들이 있기 때문이다. 이 원형이 이야기의 길을 결정해준다. 인간의 두뇌가 무한히 자유로운 상상을 하는 것이 아니라 이 원형의 길을 따라서 겉칠을 하며 응용을 하 는 것이다. 좋은 이야기 콘텐츠는 우리의 집단무의식속 원형이 제시하는 길을 가지 않으면 성공할 확률이 줄어든다.

• The Korean Journal of Physiology and Pharmacology
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• 제21권1호
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• pp.107-115
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• 2017

Over the last decade, physiologically based pharmacokinetics (PBPK) application has been extended significantly not only to predicting preclinical/human PK but also to evaluating the drug-drug interaction (DDI) liability at the drug discovery or development stage. Herein, we describe a case study to illustrate the use of PBPK approach in predicting human PK as well as DDI using in silico, in vivo and in vitro derived parameters. This case was composed of five steps such as: simulation, verification, understanding of parameter sensitivity, optimization of the parameter and final evaluation. Caffeine and ciprofloxacin were used as tool compounds to demonstrate the "fit for purpose" application of PBPK modeling and simulation for this study. Compared to caffeine, the PBPK modeling for ciprofloxacin was challenging due to several factors including solubility, permeability, clearance and tissue distribution etc. Therefore, intensive parameter sensitivity analysis (PSA) was conducted to optimize the PBPK model for ciprofloxacin. Overall, the increase in $C_{max}$ of caffeine by ciprofloxacin was not significant. However, the increase in AUC was observed and was proportional to the administered dose of ciprofloxacin. The predicted DDI and PK results were comparable to observed clinical data published in the literatures. This approach would be helpful in identifying potential key factors that could lead to significant impact on PBPK modeling and simulation for challenging compounds.

• Journal of Periodontal and Implant Science
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• 제50권5호
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• pp.313-326
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• 2020

Purpose: This study was conducted to analyze specific RNA expression profiles in gingival tissue and saliva samples in periodontitis patients and healthy individuals, and to determine their correlations in light of the potential use of microarray-based analyses of saliva samples as a periodontal monitoring tool. Methods: Gingival tissue biopsies and saliva samples from 22 patients (12 with severe periodontitis and 10 with a healthy periodontium) were analyzed using transcriptomic microarray analysis. Differential gene expression was assessed, and pathway and clustering analyses were conducted for the samples. The correlations between the results for the gingival tissue and saliva samples were analyzed at both the gene and pathway levels. Results: There were 621 differentially expressed genes (DEGs; 320 upregulated and 301 downregulated) in the gingival tissue samples of the periodontitis group, and 154 DEGs (44 upregulated and 110 downregulated) in the saliva samples. Nine of these genes overlapped between the sample types. The periodontitis patients formed a distinct cluster group based on gene expression profiles for both the tissue and saliva samples. Database for Annotation, Visualization and Integrated Discovery analysis revealed 159 enriched pathways from the tissue samples of the periodontitis patients, as well as 110 enriched pathways In the saliva samples. Thirty-four pathways overlapped between the sample types. Conclusions: The present results indicate the possibility of using the salivary transcriptome to distinguish periodontitis patients from healthy individuals. Further work is required to enhance the extraction of available RNA from saliva samples.