• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.4
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• pp.861-865
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• 2006

Takrisodokyeum (TRSDY) has been known to exert anti-tumoral activity in Korea. However, its molecular mechanism of action is not understood. In this study, we found that TRSDY induced apoptosis in androgen-independent prostate cancer DU145 cells as evidenced by DNA fragmentation and chromatine condensation in hoechst 33342 dye staining. Our data demonstrated that TRSDY-induced apoptotic cell death was accompanied by increases of PTEN and Par-4 in a time-dependent manner Taken together, these results suggest that TRSDY induce PTEN and Par-4 expression, and eventually lead to apoptotic cell death in androgen independent prostate cancer DU145 cells.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.4
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• pp.331-338
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• 2008

Ultrasonic testing for welds is widely used to ensure the integrity of facilities in NPPs. Automated ultrasonic testing(AUT) is more consistent than the manual ultrasonic testing(MUT). It can scan welded parts, examines the scanned images, and saves the results as data files. AUT in NPPs is making use of commercial systems, and there has been some difficulties in calibration of the system. An AUT system is developed. It comprises of pulser/receiver, scanner and a control program(SonicWizard). The performance demonstration for piping welds in NPPs and the piping wall thickness measurement on site were conducted to verify this system. The test results of the ultrasonic testing system developed is satisfactory and effective.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.6
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• pp.816-822
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• 2015

The objective of this study was to evaluate the anticancer effects of gamma-irradiated apigenin against various human cancer cells. Structural changes were analyzed by high pressure liquid chromatography. Gamma-irradiated apigenin showed a new peak distinguished from the main peak of apigenin (non-irradiated). Cytotoxic effects in human normal cells (HS68) were not observed upon gamma-irradiated and non-irradiated apigenin treatment. However, gamma-irradiated apigenin treatment significantly increased cytotoxicity against non-small lung cancer cells. For apoptosis induction activity tested by Annexin V/PI staining, gamma-irradiated apigenin showed a stronger effect than non-irradiated apigenin, and the level of reactive oxygen species was apparently elevated by gamma-irradiated apigenin treatment. These results suggest that gamma irradiation could be an effective method for development of a new physiological compound from an original compound by inducing structural changes.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.412-427
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• 2016

댐의 건설은 자연하천에서 퇴적과 침식의 유사 순환과정에 영향을 주고 저수지 퇴사(reservoir sedimentation)를 야기한다. 이러한 현상은 댐의 건설 이후 장기간 축적되면서 이수와 취수에 대한 영향을 가져오기 때문에 댐 관리와 설계를 위해 정확한 추정이 필요하다. 퇴사량을 산정하는 방법에는 실측자료를 방법과 실제 유사량 자료를 이용하는 방법 그리고 경험공식을 이용하는 방법 등이 있으나, 가용한 자료의 부족으로 주로 경험 공식에 의존하고 있다. 이에 본 연구에서는 국내 대규모 다목적댐에 적합한 비퇴사량 산정 경험 공식을 제안하고자 하였다. 이를 위해 먼저 기존의 공식을 조사 및 검토하여 비퇴사량에 영향을 미칠 만한 여러 인자들을 선정하였다. 총 8개 국내 대규모 다목적댐의 비퇴사량 자료와 제원을 이용하여 다중 회귀분석을 실시하여 최종적인 식을 제안하였다. 그 결과, 대규모 다목적댐의 비퇴사량에 영향을 미치는 인자로 연평균 강우량(P, mm),연평균 유입량(I, cms), 유역 평균경사(S, %),저수지 길이(L, km),저수용량/유역면적(C/A, $m^3/km^2$)을 채택하였으며, 제안된 식을 이용하여 산정한 비퇴사량과 실측 비퇴사량의 상관계수와 결정계수는 각각 0.985, 0.970으로 확인되었다. 아울러, 다중 공선성 분석에서도 모두 일반적인 기준치를 범위 안에 존재함을 확인하면서, 선정된 독립변수들이 통계적으로 유의함을 확인하였다. 허나, 가용 자료의 부족과 불확실성으로 인해 여전히 한계점이 존재한다. 충분한 비퇴사량 실측 자료가 구축된다면, 보다 신뢰도 높고 발전된 형태의 경험 공식의 제안이 가능할 것이다.

• Journal of Adhesion and Interface
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• v.8 no.4
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• pp.14-22
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• 2007

In the present study, the effect of milled glass powder and liquid-type nitrile rubber (NBR) on the thermal stability of phenolic resin and the dynamic mechanical properties of glass braid/phenolic composites has been investigated by means of thermogravimetric analysis and dynamical mechanical analysis. It was found that both milled glass power and NBR filled in the waterborne phenolic resin significantly influenced the thermal stability of phenolic resins and the storage modulus and tan delta of the composites. The presence of glass powder increased the thermal stability of the phenolic resin, whereas the presence of NBR resulted in the weight loss in the specific temperature range. The thermal stability of the phenolic resins without and with the fillers was dependent not only on the cure temperature but also on the cure time. The variation of the storage modulus and tan ${\delta}$ of strip-type glass braid/phenolic composites was also influenced with the introduction of glass powder and NBR to the phenolic matrix as well as by the cure conditions given.

• Journal of the Korean earth science society
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• v.42 no.3
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• pp.365-380
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• 2021

This study aimed to explore the characteristics of scientific observation and reasoning of gifted middle-school students in rock identification. Five rock samples that are considered important as per science textbooks, including igneous, metamorphic, and sedimentary rocks, were provided to 19 first-year middle-school students attending a gifted education center. Students were asked to infer the formation process, type, and name of each rock. The results showed that the characteristics of rocks that students primarily paid attention to included color, texture, and structure. Students immediately succeeded in identifying common rocks based on memory; however, meaningful inferences were not made. In case of rocks that students faced difficulty discriminating, significant reasoning processes were revealed through discourse. In addition, although scientific reasoning was properly constructed based on meaningful observations, there were cases wherein rock identification failed. These results will contribute to determining the current level of understanding of middle-school students in rock identification activities and finding ways to provide students with meaningful scientific observation and inference experiences through rock identification in the school field.

• Journal of Internet Computing and Services
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• v.22 no.5
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• pp.79-86
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• 2021

As the usefulness of big data analysis has been drawing attention, many studies in the business research area begin to use big data to predict firm performance. Previous studies mainly rely on data outside of the firm through news articles and social media platforms. The voices within the firm in the form of employee satisfaction or evaluation of the strength and weakness of the firm can potentially affect firm value. However, there is insufficient evidence that online employee reviews are valid to predict firm value because the data is relatively difficult to obtain. To fill this gap, from 2014 to 2019, we employed 97,216 reviews collected by JobPlanet, an online firm review website in Korea, and developed a machine learning-based predictive model. Among the proposed models, the LSTM-based model showed the highest accuracy at 73.2%, and the MAE showed the lowest error at 0.359. We expect that this study can be a useful case in the field of firm value prediction on domestic companies.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.626-638
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• 2021

This study is about a life history. Through investigating the life of retired teachers in preschool, elementary, and middle schools, authors wanted to explore the meaning of retirement and the process of adaptation to find out their personal and social needs in post-retirement life. Studies have shown that their experiences at childhood have greatly influenced the performance of one's profession, such as contributing to setting limits on behaviors of their students. In the period of interdependence, they have contributed to serving society and the nation beyond as a professional, and in the second half of his teaching career, they have learned that their painful experience was a resource and have realized that changing mind can make the world changed. Since teachers' behavior affects on many subjects unlike other jobs, rewards or satisfaction from the job was bigger than any other jobs. However, after retirement, they felt a sense of emptiness in life without any sense of belonging or accomplishment, while feeling happiness and infinite freedom in other hand. Thy still go forward for life challenging to new study.

• KNOM Review
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• v.23 no.1
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• pp.26-33
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• 2020

Bitcoin is an electronic money that does not rely on centralized institutions such as banks and financial institutions, unlike the world's paper currencies such as dollar, won, euro and yen. In Bitcoin network, a block with transaction details is generated by mining, and the message that the block has been created is broadcast to all participating nodes in a broadcasting method to secure reliability through verification. Likewise, the mining and block propagation methods in the Bitcoin network are greatly affected by the performance of the P2P network. For example, in the case of mining, the node receiving the reward for mining varies depending on whether the block is first mined in the network and the proof of mining is propagated faster. In this paper, we applied local characteristics and Round-to-Trip(RTT) measurement to solve the problems of the existing neighbor connection method and block propagation method performed in Bitcoin network. An algorithm to improve block propagation speed is presented. Through experiments, we compare the performance of the improved algorithm with the existing algorithm to verify that the overall block propagation time is reduced.

• Journal of Practical Agriculture & Fisheries Research
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• v.14 no.1
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• pp.195-209
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• 2012

1) 버섯종균 생산 시스템 개선 버섯의 품질과 수량을 좌우하는 주요 요인은 종균의 활력이다. 그러나 말라위에서는 종균의 활력이 낮아 조그마한 350cc 음료수 병에 배양 완성하는데 20일이 소요되는 등 노동력의 비효율성을 개선하였다. 따라서 350cc 병을 3500cc 비닐봉지로 개선하여 입봉하는데 소요되는 시간을 10배 이상으로 단축 개선하였다. 또한 곡립종균을 액체종균으로 대처한 결과 균사생장 속도가 빨랐으며 작업속도가 빨라졌다. 곡립 수수를 밀로 대체하여 종균제조 노동력을 효율적으로 전환하였다. 2) 버섯재배사 환경관리 개선 버섯재배의 4대 환경조건은 온도, 습도, 환기, 광이다. 그러나 말라위의 버섯재배사는 4대 환경조건 조절을 자연상태에 의존하고 있다. 그럼에도 불구하고 비닐로 커버된 상태에서 문을 닫아두어 과습이 되고 환기가 되지않았다. 이를 개선하기 위하여 직경 5cm 환기공을 버섯재배사 당 4개씩 만들도록 지도하였다. 3) 버섯배지 개선 말라위에서는 옥수수 대를 잘라 버섯배지로 주로 이용하고 있다. 이를 개선하여 말라위 북부지역(다광)에 대규모 사탕수수 공장을 방문하여 사탕수수 박을 이용하여 버섯재배 기술을 교육하였다. 이를 이용함으로서 버섯 균사생장속도를 빠르게 하고 균사량의 축적을 높이도록 하여 고품질 다수확하는데 교육을 하고 컨설팅을 실시하여 개선하였다. 4) 버섯 배지 야외발효 후 지면재배 시도로 시간 단축과 비용절감 말라위 버섯배지 혼합제조법은 옥수수대 한가지로서 영양원이 없다. 이를 개선하여 배지를 수분을 흡수시킨 후 야외 퇴적하므로서 배지의 물리성을 개선하고 야외발효 과정 중 양분이 합성되어 양질의 배지를 만드는 방법이다. 야외발효한 배지를 봉지에 담아 균상에 입상하는 불편함과 나무로 만들어진 균상대의 과습으로 인한 곰팡이 발생과 개미 침입으로 썩는 것 등을 방지하기 위하여 지면재배 방법으로 개선하였다. 이 지면재배는 균상 만드는 나무재료와 인건비 절감. 병해충 발생 방제 뿐만아니라 고품질 다수확할 수 있는 방법으로 개선 교육과 시범 시연을 실시하였다.