• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.4
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• pp.362-370
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• 2001

In this paper, we proposed multispectral image compression method using CIP (classified inter-channel prediction) and SVQ (selective vector quantization) in wavelet domain. First, multispectral image is wavelet transformed and classified into one of three classes considering reflection characteristics of the subband with the lowest resolution. Then, for a reference channel which has the highest correlation and the same resolution with other channels, the variable VQ is performed in the classified intra-channel to remove spatial redundancy. For other channels, the CIP is performed to remove spectral redundancy. Finally, the prediction error is reduced by performing SVQ. Experiments are carried out on a multispectral image. The results show that the proposed method reduce the bit rate at higher reconstructed image quality and improve the compression efficiency compared to conventional methods. Index Terms-Multispectral image compression, wavelet transform, classfied inter-channel prediction, selective vetor quantization, subband with lowest resolution.

• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.537-548
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• 2015

This study aims to identify and compare the patterns of scientific questions generation among elementary science-gifted and general students when conducting observational tasks. The pattern in generating scientific questions, which is distinguished from other types of scientific questions, is the manner that students generate a variety of types of questions in an inquiry process. To analyze the patterns in generating scientific questions, the task of observing dry grapes in soda pop, candlelight, and dyed celery were selected as suitable tasks. The subjects were 26 science-gifted students participating in a gifted education program and 27 general students in an elementary school in the same city. They were all sixth graders. The results of this study are as follows: First, the patterns of scientific questions generation among gifted students and general students during observational tasks were classified into five patterns: [Pattern 1] single, [Pattern 2] sequential, [Pattern 3] repetitive, [Pattern 4] circulative, [Pattern 5] repetitive, and circulative. Second, gifted students and general students presented all of the five patterns, but the frequency of the patterns indicated differences between the two groups. The gifted students primarily presented [Pattern 3] and [Pattern 5]. On the other hand, the general students mainly presented [Pattern 1], [Pattern 2], and [Pattern 3]. These results suggest that the ways of generating scientific questions are very much as important as the types of questions. Teachers can establish teaching-learning strategies for generating scientific questions appropriate to learner's characteristics.

• Journal of Gastric Cancer
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• v.16 no.4
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• pp.247-253
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• 2016

Purpose: The aim of this study was to establish an anthropometric reference of the stomach for gastric cancer surgery and a modeling formula to predict stomach length. Materials and Methods: Data were retrieved for 851 patients who underwent total gastrectomy at the Seoul National University Hospital between 2008 and 2013. Clinicopathological data and measurements from a formalin-fixed specimen were reviewed. The lengths (cm) of the greater curvature (GC) and lesser curvature (LC) were measured. Anthropometric data of the stomach were compared according to age, body weight, height (cm), and body mass index. To predict stomach length, two multiple regression analyses were performed. Results: The mean lengths of the GC and LC were $22.2{\pm}3.1cm$ and $16.3{\pm}2.6cm$, respectively. The men's GC length was significantly greater than the women's ($22.4{\pm}3.1cm$ vs. $21.2{\pm}2.9cm$, P=0.003). Patients aged >70 years showed significantly longer LC than those aged <50 years ($16.9{\pm}2.9cm$ vs. $15.9{\pm}2.4cm$, P=0.002). Patients with body weights >70 kg showed significantly longer GC than those with body weights <55 kg ($23.0{\pm}2.9cm$ vs. $21.4{\pm}3.2cm$, P<0.001). In the predicted models, 4.11% of the GC was accounted for by age and weight; and 4.94% of the LC, by age, sex, height, and weight. Conclusions: Sex, age, height, and body weight were associated with the length of the LC, while sex and body weight were the only factors that were associated with the length of the GC. However, the prediction model was not sufficiently strong.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.547-560
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• 2020

The study tries to explore the ideas of the 10-20 generations to find improvements in the education policy for future South and North Korea relationship and provide implications on the current unification education and the South and North Korea relationship. Furthermore, through the ideas of the 10th and 20th generations, the goal was to draw in-depth discussions on how to view relations with North Korea for the future development of the South Korea. Afterwards, a total of 14 people(6 teenagers and 8 20s) were selected through a snowballing, and a total of 14 people from each group participated in three focus group interviews. The results were as follows. First, the participants in this study on South and North Korea relation reported three perspectives: the 'nationalist view', the 'pragmatic view' and the 'ideological and systemic view'. Second, There were both negative and positive about North-South relationship. But positive emotions and attitudes were mainly influenced by the media, and negative those were influenced by repetitive and compulsory education. Unlike passive interviews in the first session, during the course of the interview the study participants expressed their opinions and talked about the future of the South and North Korea relations. It is the value of the study, and provides future generations with a sense of what education is necessary in designing the future of Korea, interacting with South and North Korea relation.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.684-692
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• 2007

The object of this study is to identify the factors that is making and promoting cooperation for the unified forest fire administration, and then introduce cooperation process and cooperation manual for an effective forest management. For this purpose, the case studies were carried about "The East Coastal Forest Fire Administration Center" and "The Forest Fire Administration Center in Mt. Jiri Area" to have obtained excellent results by cooperation among administrative districts, and cooperative factors were extracted through analyzing each steps. That is, cooperation steps were divided into 4 steps of Initiation, Planning, Implementation, Benefiting, and in-depth interview and questionnaires were carried for extracting cooperation factors by each step for the unified cooperative forest management system. And with AHP analysis, essential four factors were extracted by each step based on priority order. Finally with the base of the essential 4 factors by each step, the cooperation process and manual appliable to forestry cooperation project were developed. This will be a guideline in order to achieve successful forest administrations through the cooperation among local administrative governments.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.318-318
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• 2010

전기로를 이용하여 셀렌화한 $CuInSe_2$ (CIS)박막에 대해 연구한 결과를 발표하고자 한다. 화석연료의 과도한 사용으로 지구온난화의 환경문제가 대두되면서 영구적이고 무상의 태양에너지 이용에 대한 필요성이 점차 높아지고 있다. 빛에너지를 전기에너지로 변화시키기 위한 태양전지는 재료에 따라 다양하게 개발되고 있으며 그 중 가장 주목을 받고 있는 것 중의 하나가 $CuInSe_2$을 흡수층으로 하는 CIS 박막 태양전지이다. CIS 박막은 태양전지의 흡수층으로 사용되는데 직접천이형 밴드구조를 가지고 있고, 약 $10^5\;cm^{-1}$의 높은 광흡수계수를 가지고 있어 태양전지의 흡수층으로 적합한 물질로 각광받고 있다. 에너지 밴드갭이 1eV로 실리콘과 유사한 밴드갬을 가지고 있으나 이는 Ga, Al을 In 대신 치환함으로 조절할 할 수 있다. 무엇보다도 유리와 같은 저가의 기판위에 스퍼터와 같은 장치로 대면적 CIS 태양전지를 만들수 있다는 것이 산업적인면에서의 장점으로 알려져 있다. 본 연구에서는 $50mm{\times}50mm$ 넓이의 sodalime 유리판을 기판으로 하여 CIS 박막을 제조하고 연구하였다. 스퍼터를 이용하여 유리기판 위에 Mo (Molybdenum) 을 증착하고 그 위에 Cu-In막을 증착하였다. Cu-In/Mo/유리기판 시료는 전기로에 도입되어 셀렌화 처리 하였다. 전기로는 $10^{-1}$ Torr 정도의 진공을 수분간 유지하여 반응할 수 있는 공기(산소)를 제거하였다. 진공 혹은 5N의 고순도 질소를 흘려주며 열을 가하여 셀렌화를 하였다. 전기로에는 1g의 셀레늄(Se)이 Cu-In/Mo/유리기판 시료와 함께 도입되었다. Se이 Cu-In 막과 높은 반응성을 갖도록 Se과 Cu-In 시료는 그라파이드 상자에 함께 넣었고, 그라파이트 상자는 전기로에 넣어 셀렌화하였다. 셀렌화 온도는 $400^{\circ}C{\sim}500^{\circ}C$까지 변화시켜 가며 CIS 박막을 제조하였으며 그 물성도 조사하였다. 물성 조사는 사진, 현미경, SEM, EDX, XRD, Hall effects를 이용하였다. 셀렌화 온도가 $450^{\circ}C$ 이상에서는 CIS 박막의 흡착성이 낮아 CIS 박막이 Mo 표면에서 떨어짐을 알 수 있었다. 셀렌화 후 박막에 함유된 Se은 48%~49% 정도있었다. 제조된 CIS 박막시료를 SEM으로 확인한 결과 생성된 CIS/Mo 사이에 계면층이 생겼있음 알 수 있었다. 이러한 계면층은 $MoSe^2$층으로 사료되고, 셀렌화 온도가 높으면 계면층의 두께도 증가되는 경향을 보였다. 셀렌화 온도가 높아질수록 많은 양의 산소가 CIS 박막에 들어가는 것도 알 수 있었다. 학술회의에서 보다 깊은 조사결과를 발표하고자 한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.374-374
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• 2014

의료용 X-ray는 과거 analog 방식과, 연구가 진행 중이며 현재 많이 사용되고 있는 digital 방식으로 나누어진다. 최근, 광도전체와 형광체 기반의 flat panel X-ray detector의 발전에 따른 상용화가 이루어지고 있으며, 많은 발전 가능성이 제기되고 있다. flat panel X-ray detector 검출방식은 direct method (직접 방식)와 indirect method (간접 방식)로 나누어진다. 본 연구는 일반적으로 상용화 되어있는 amorphous seleinum (비정질 셀레늄)의 큰 일함수에 의한 저 해상력이라는 단점을 보완하기 위해, 작은 일함수를 가지는 물질을 사용하여, 영상을 얻을 시에 높은 해상력으로 표현할 수 있도록 하고, 원자번호가 높은 물질을 사용하여 X-ray 흡수율을 높일 수 있도록 기존 direct method에 많이 사용되고 있는 amorphous seleinum 기반 digital X-ray detector가 아닌, 이러한 장점을 충족시킬 수 있는 PbI2 물질 층을 사용하여 시편을 제작 하였다. PbI2를 같은 두께로 올린 후, 물질 층 상부에 Au 전극 면적을 다른 size로 제작한 시편으로 X-ray에 노출 시켰다. 이는 상부 전극 size 차이에 따른 신호 차이를 측정하여 전기적 특성을 평가하기 위한 것이다. 전도성을 띠고 있는 ITO (Indium - Tin - Oxide) glass를 이용하여 screen printing 방법으로 제작하였다. PbI2층을 약 160~180 um두께, $3cm{\times}3cm$ size로 5개 제작하였으며, 상부 전극으로는 Au를 진공 증착 시켰다. 상부 전극 size는 각각 시편 5개에 $0.5cm{\times}0.5cm$, $1cm{\times}1cm$, $1.5cm{\times}1.5cm$, $2cm{\times}2cm$, $2.5cm{\times}2.5cm$로 PbI2 물질 층 중앙에 증착 시켰다. 이러한 설정으로 X-ray 노출 시 관찰할 수 있는 PbI2의 전기적인 특성을 평가할 수 있었다. 관전압을 40 kVp, 60 kVp, 80 kVp, 100 kVp, 120 kVp, 140 kVp로 설정하고, 관전류는 100 mA로 설정하였으며, Dark current, Sensitivity를 측정하였다. Dark current와 Sensitivity를 측정한 뒤, 그 값을 이용하여 SNR (신호 대 잡음 비)값을 구해보았다.실험 결과 단위면적당 signal과 SNR을 분석할 수 있었다. 80 kVp로 기준을 잡고 결과 값을 보면 $0.5cm{\times}0.5cm$ 시편에서 2.92 nC/cm2, $2.5cm{\times}2.5cm$ 시편에서 0.84 nC/cm2로 상부 전극 크기가 작을수록 더 좋은 신호를 측정할 수 있었다. 똑같은 기준에서 SNR을 계산 해 보았을 때, $0.5cm{\times}0.5cm$ 시편에서 6.46, $2.5cm{\times}2.5cm$ 시편에서 1.91로 SNR역시 상부 전극 크기가 작을수록 더 큰 값을 확인할 수 있었다. 이러한 결과는 edge-effect의 영향으로 인해 나온 결과라고 할 수 있다. 이러한 실험 결과, detector 제작 시, 같은 물질을 사용하여 더 높은 효율을 내기 위해서는 큰 size의 상부 전극 보다는 작은 size의 상부 전극을 증착 시키는 것이 전기적 특성을 더욱 효율적으로 평가할 수 있을 것이라고 사료된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1830-1840
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• 2013

This study attempts to set a pathway on smoking cessation behavior and to verify it by an analysis of the students who smoke. The study was performed with an analysis of the data of 160 students at N university. There were statistically significant differences among the students who desired to quit smoking (or who expressed interest in quitting smoking) in the following areas: thoughts about smoking cessation, intention to quit smoking, health promoting behavior (HPB), and depression cognitive scale (DCS) (p<.01). The student's major was also shown to have a statistically significant influence on one's intention to quit smoking (p=.034) and HPB (p=.044). As thoughts about smoking cessation increased, HPB also showed a significant increase (p<.05). Additionally, as HPB scores increased, DCS scores decreased significantly (p<.001), and thoughts about smoking cessation increased, while DCS scores decreased significantly (p=.027). This study confirmed the pathway that the intention to quit smoking influences DCS by mediating the effects of HPB and that thoughts about smoking cessation influence DCS.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.18 no.4
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• pp.253-260
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• 2015

Purpose: The aim of the present study was to investigate the clinical features and outcome of eosinophilic gastroenteritis (EGE) in children. Methods: Our study enrolled 24 children who were diagnosed with EGE from 1993 to 2014 at the Department of Pediatrics, Seoul National University Children's Hospital. The patients' clinical manifestations, treatments, and outcomes were reviewed from the medical records. Results: The mean age at diagnosis was 5.3 years. Most patients had gastrointestinal symptoms including diarrhea (54.2%) and abdominal pain (45.8%). Peripheral eosinophilia was present in 91.7% of the patients. Thirteen patients (54.2%) showed anemia, and 15 patients (62.5%) had hypoalbuminemia. EGE was classified as mucosal, subserosal, or muscular in 75.0%, 20.8%, and 4.2% of cases, respectively. Three patients showed gastroduodenal ulcers upon endoscopic analysis. A history of allergy was reported in 13 patients, including atopic dermatitis, allergic rhinitis, and asthma. Five patients (20.8%) improved with food restrictions. Among the 19 patients treated with steroids, 11 (57.9%) discontinued steroid treatment without subsequent relapse, 4 (21.1%) relapsed after ceasing steroid treatment, and 4 (21.1%) showed no response to steroids. Two patients who were resistant to steroids underwent therapeutic surgery. The presence of gastroduodenal ulcers was significantly associated with relapse and steroid resistance. Conclusion: A high suspicion of EGE is warranted when children have nonspecific gastrointestinal symptoms and peripheral eosinophilia. Most patients improved with food restrictions or steroid treatment, although one-third of patients showed a relapse or steroid resistance.

• Journal of Life Science
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• v.22 no.8
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• pp.1018-1023
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• 2012

Snail is a zinc finger transcription factor that induces epithelial-to-mesenchymal transition (EMT), which promotes tumor invasion and metastasis by repressing E-cadherin expression. In addition, Snail restricts the cellular apoptotic response to apoptotic stimuli or survival factor withdrawal; however, its molecular mechanism remains largely unknown. In this study, we have investigated the mechanism underlying Snail-mediated chemoresistance to 5-fluorouracil (5-FU), one of the most widely used anti-cancer drugs. When Snail was overexpressed by doxycycline (DOX) in MCF-7 #5 cells, it inhibited 5-FU-induced apoptotic cell death and switched the cell death mode to necrosis. Snail expression, either by DOX treatment in MCF-7 #5 cells or by the transfection of Snail expression vectors pCR3.1-Snail-Flg, phosphorylation-resistant pCR3.1-S104, and 107A Snail-Flg in MCF-7 cells specifically induced PTEN down-regulation/inactivation and Akt/PKB activation, without affecting ERK1/2 activity. In addition, Snail prominently suppressed 5-FU-induced increases in p53 levels. These findings demonstrate that Snail switches 5-FU-induced apoptosis to necrosis through the activation of Akt/PKB and the down-regulation of p53 levels.