• Asian-Australasian Journal of Animal Sciences
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• 제28권12호
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• pp.1784-1793
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• 2015

This study was carried out to investigate the effects of tributyrin (TB) on the growth performance, pro-inflammatory cytokines, intestinal morphology, energy status, disaccharidase activity, and antioxidative capacity of broilers challenged with lipopolysaccharide (LPS). A total of 160 one-day-old Cobb broilers were allocated to 1 of 4 treatments, with 4 replicated pens per treatment and 10 birds per pen. The experiment consisted of a $2{\times}2$ factorial arrangements of treatments with TB supplementation (0 or 500 mg/kg) and LPS challenge (0 or $500{\mu}g/kg$ body weight [BW]). On days 22, 24, and 26 of the trial, broilers received an intraperitoneal administration of $500{\mu}g/kg$ BW LPS or saline. Dietary TB showed no effect on growth performance. However, LPS challenge decreased the average daily gain of broilers from day 22 to day 26 of the trial. Dietary TB supplementation inhibited the increase of interleukin-$1{\beta}$ (in the jejunum and ileum), interleukin-6 (in the duodenum and jejunum), and prostaglandin $E_2$ (in the duodenum) of LPS-challenged broilers. Similar inhibitory effects of TB in the activities of total nitric oxide synthase (in the ileum) and inducible nitric oxide synthase (in the jejunum) were also observed in birds challenged with LPS. Additionally, TB supplementation mitigated the decrease of ileal adenosine triphosphate, adenosine diphosphate and total adenine nucleotide and the reduction of jejunal catalase activity induced by LPS. Taken together, these results suggest that the TB supplementation was able to reduce the release of pro-inflammatory cytokines and improve the energy status and anti-oxidative capacity in the small intestine of LPS-challenged broilers.

• 한국정보처리학회논문지
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• 제6권4호
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• pp.1009-1021
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• 1999

본 논문에서는 네트워크 상에서의 공동저작을 위한 프로토타입 시스템의 설계원칙과 구조를 기술한다. 본 시스템은 주석 달기와 주석 확인을 위해서 광범위한 문서공간에서의 네비게이션 기능, 문서 locking 과 작업기록을 포함한 작업그룹 모니터 링 및 관리를 위한 도구를 포함하고 있다. 설계된 프로토타입은 인간과 컴퓨터 상호작용, 그룹 사호작용, 그룹지원, 문서구조화의 구현 시험을 위한 testbed로 제공 될 수 있으며, 프로토타입의 개발배경과 문제점도 지적한다.

• 영어어문교육
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• 제17권4호
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• pp.75-95
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• 2011

The purpose of this study was to evaluate a group activity, reciprocal peer tutoring (RPT), in order to investigate advantages and challenges of RPT in promoting cooperative and collaborative learning environment for EFL University reading instruction. The participants in this study were 89 students taking an English reading course at a Korean university. RPT is a learning strategy whereby learners help each other and learn by teaching. This program was supported by a Vygotskyan perspective which assumes that learners gain mastery and develop cognitive skills through social interaction with more proficient others and their environment. This study relied particularly on participant perceptions through questionnaire survey and Anonymous Online class Report of the course. This study showed various advantages for tutors such as learning through teaching and becoming more autonomous and responsible for their own learning. Non-threatening and highly motivating learning atmosphere are parts of benefits for tutees. Other advantages for tutees included improved level of academic self-confidence, and motivation. This study also revealed several drawbacks associated with the problem of inaccuracy in students' production and students' demand for more direct teacher role. (182 words).

• 정보과학회 컴퓨팅의 실제 논문지
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• 제22권10호
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• pp.504-512
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• 2016

본 논문에서는 협업 필터링을 통한 개인 맞춤형 이벤트 추천 기법을 제안한다. 제안하는 기법은 사용자의 행위 및 관계성 분석, 협업 필터링을 통해 사용자의 평가되지 못한 속성 값을 예측한다. 또한, 사용자의 성향을 보다 정확하게 파악하기 위해 사용자의 최근 방문 기록이나 상황 정보를 고려하여 사용자의 최신 성향을 관리한다. 이를 통해 새로운 이벤트가 발생하였을 때 참여할 확률이 높을 것으로 예상되는 사용자에게만 이벤트를 추천하여 무분별한 추천을 방지한다. 제안하는 이벤트 추천 기법의 우수성을 보이기 위해 다양한 성능 평가를 수행한다.

• 한국통신학회논문지
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• 제35권8C호
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• pp.713-719
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• 2010

협력 스펙트럼 감지 방식은 페이딩이 존재하는 환경에서 1차 사용자의 활동 유무를 알아내는 효과적인 방식으로 알려져 있다. 지금까지 협력 스펙트럼 감지에 관해 이루어진 대부분의 연구는 2차 사용자가 내린 국부 스펙트럼 감지 결정들이 통계적으로 서로 독립이라는 가정에 기초한 것이다. 그러나 실제 환경에서는 이러한 전제가 성립하지 않을 수 있다. 이 논문에서는 지역적으로 이웃한 2차 사용자의 국부 스펙트럼 감지 결정들 사이에 동일한 상관도가 존재하고, 이웃하지 않은 경우에는 통계적으로 독립인 인지 무선 네트워크를 대상으로 하여, AND 규칙과 OR 규칙을 사용하는 협력 스펙트럼 감지 방식의 성능을 분석하였다. 분석 결과, 상관 정도가 강할 때 AND 방식이 OR 방식에 비해 우수한 성능을 나타냄을 확인할 수 있었다.

• 한국보육지원학회지
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• 제15권3호
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• pp.61-81
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• 2019

Objective: This study aimed to examine the effects of collaborative activities by utilizing picture books in order to improve the self-regulation and perspectivetaking abilities among four-year-olds. Methods: A total of 52 four-year-olds(control group 26, experimental group 26) attending two classes at D kindergarten located in B city participated in this study. Before and after the activities, all participants individually took a social perspective taking ability instrument and rated their self-regulation with a teacher. Data were analyzed by conducting ANCOVA in the way of setting pre-test scores as the covariate and post-test scores as the dependent variable. Results: First, the total and subarea of self-regulation in the experimental group was higher than the control group. Second, the cognitive and emotional perspective taking abilities in the experimental group were higher than the control group in all cares. Conclusion/Implications: The results of this study suggest that collaborative activities using picture books are effective in improving young children's selfregulation and perspective-taking abilities.

• Educational Technology International
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• 제13권1호
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• pp.207-231
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• 2012

The purpose of this study is to analyze the effects of Critical Thinking Strategy supporting argumentation activities between learners. The research question is whether the form of Critical Thinking Strategy offered to support meaningful interaction of collaborative argumentation between learners influences the knowledge acquisition, learning outcome, and student satisfaction. For this, the collaboration outcome of the group, the level of individual knowledge acquisition, the level of students satisfaction were measured as outcome of argumentation activity and their differences analyzed. This study concludes the following: A comparison of the group that was provided with Critical Thinking Strategy (test group) and the group provided with general argumentation scaffolds (compared group) showed there wasn't statistically significant differences in the quality of the learning outcome of collaboration between the groups and in students satisfaction. But there was significant difference in the degree of individual acquisition depending on the offering of scaffolding for Critical Thinking. Therefore, as premised in this study, supporting meaningful mutual interaction between learners during collaborative argumentation using Critical Thinking Strategy has a positive influence on the individual acquisition of domain knowledge. The group provided with scaffolding for Critical Thinking gained higher effect in the degree of knowledge sharing and individual acquisition of domain knowledge compared to the group provided with general argumentation scaffolding.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3805-3810
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• 2015

Arsenic trioxide (ATO) has been found to exert anti-cancer activity in various human malignancies. However, the molecular mechanisms by which ATO inhibits tumorigenesis are not fully elucidated. In the current study, we explored the molecular basis of ATO-mediated tumor growth inhibition in pancreatic cancer cells. We used multiple approaches such as MTT assay, wound healing assay, Transwell invasion assay, annexin V-FITC, cell cycle analysis, RT-PCR and Western blotting to achieve our goal. We found that ATO treatment effectively caused cell growth inhibition, suppressed clonogenic potential and induced G2-M cell cycle arrest and apoptosis in pancreatic cancer cells. Moreover, we observed a significant down-regulation of Skp2 after treatment with ATO. Furthermore, we revealed that ATO regulated Skp2 downstream genes such as FOXO1 and p53. These findings demonstrate that inhibition of Skp2 could be a novel strategy for the treatment of pancreatic cancer by ATO.

• 한국통신학회논문지
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• 제35권7C호
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• pp.642-650
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• 2010

협력 스펙트럼 감지(collaborative spectrum sensing) 방식은 지역적으로 분산되어 있는 다수의 부 사용자(secondary user)들이 협력하여 주 사용자(primary user)의 활동을 감지하는 방법으로, 페이딩으로 인해 발생하는 검파 성능의 손실을 상당히 줄일 수 있는 것으로 알려져 있다. 현재까지 이 방식에 대한 대부분의 연구는 개별부 사용자들이 내린 스펙트럼 감지 결정이 통계적으로 서로 독립이라고 가정한 것에 기초한 것이다. 그러나 실제 상황에서는 음영 효과(shadowing effect)로 인해 이 가정이 유효하지 않은 경우가 발생한다. 본 논문에서는 부 사용자들이 직선상에 일정 간격으로 배치되고, 이웃하는 부 사용자의 스펙트럼 감지 결정사이에서만 상관 관계가 존재하는 경우를 대상으로 하여, 상관 정도가 협력 스펙트럼 감지 방식의 성능에 미치는 영향과 그에 따른 인지 무선 시스템의 전송 용량 변화를 분석하고자 한다. 이때 개별 부 사용자의 결정을 융합하는 규칙으로는 AND 규칙과 OR 규칙을 고려하였다. 분석 결과 AND 융합 규칙을 사용하는 경우가 OR 규칙을 사용하는 경우보다 전송용량 측면에서 우수하다는 점을 확인할 수 있었다.

• Journal of Ginseng Research
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• 제44권1호
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• pp.14-23
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• 2020

Ginseng has been used as a popular herbal medicine in East Asia for at least two millennia. However, 20(R)-ginseng saponins, one class of important rare ginsenosides, are rare in natural products. 20(R)-ginseng saponins are generally prepared by chemical epimerization and microbial transformation from 20(S)-isomers. The C20 configuration of 20(R)-ginseng saponins are usually determined by ¹³C NMR and X-ray single-crystal diffraction. 20(R)-ginseng saponins have antitumor, antioxidative, antifatigue, neuroprotective, and osteoclastogenesis inhibitory effects, among others. Owing to the chemical structure and pharmacological and stereoselective properties, 20(R)-ginseng saponins have attracted a great deal of attention in recent years. In this study, the discovery, identification, chemical epimerization, microbial transformation, pharmacological activities, and metabolism of 20(R)-ginseng saponins are summarized.