• Title/Summary/Keyword: Lee Geun-sam

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Analyses of Stress Intensity Factors and Evaluation of Fracture Toughness in Adhesively Bonded DCB Joints (DCB 접착이음에 대한 응력세기계수의 해석 및 파괴인성의 평가)

  • Jeong, Nam-Yong;Lee, Myeong-Dae;Gang, Sam-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.6 s.177
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    • pp.1547-1556
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    • 2000
  • In this paper, an evaluation method of fracture toughness to apply interfacial fracture mechanics was investigated in adhesively bonded double-cantilever beam (DCB) joints. Four types of adhesively bonded DCB joints with an interface crack were prepared for analyses of the stress intensity factors using boundary element method(BEM) and the fracture toughness test. From the results of BEM analysis and fracture toughness experiments, it is found that the stress intensity factor, K1 is a parameter driving the fracture of adhesively bonded joints. Also, the evaluation method of fracture toughness by separated stress intensity factors of mixed mode cracks was proposed and the influences of mode components for its fracture toughness are investigated in adhesively bonded DCB joints.

A Case of Gastric Lipoma with Upper Gastrointestinal Bleeding (상부위장관 출혈을 동반한 위 지방종 1예)

  • Gu, Min Geun;Kim, Kook Hyun;Park, Byung Sam;Jung, Sung Yun;Jeong, Yo Han;Lee, Dong Won;Shin, Hyeong Chan;Gu, Mi Jin
    • Journal of Yeungnam Medical Science
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    • v.30 no.2
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    • pp.132-135
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    • 2013
  • Gastric lipoma is a typical benign submucosal tumor that is usually asymptomatic and is generally detected incidentally when performing gastroscopy. However, depending on its size and location, an atypical gastrointestinal lipoma can cause abdominal pain, diarrhea, constipation, intestinal obstruction, intussuception and life-threatening gastrointestinal bleeding. We report herein a case of gastric lipoma with bleeding in a 43-year-old man. The gastroscopy showed a $4{\times}4$ cm ulcero-fungating submucosal mass at the anterior wall of the gastric antrum. Laparoscopic gastric wedge resection was performed and the lesion was diagnosed as gastric lipoma.

An Effective Buffer Management Scheme for Sequential and Looping References (순차 참조와 순환 참조들을 고려한 버퍼 캐쉬 관리 기법)

  • Kim, Jong-Min;Choe, Jong-Mu;Kim, Je-Seong;Lee, Dong-Hui;No, Sam-Hyeok;Min, Sang-Ryeol;Jo, Yu-Geun;Kim, Jong-Sang
    • Journal of KIISE:Computer Systems and Theory
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    • v.28 no.1_2
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    • pp.33-44
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    • 2001
  • 최근 버퍼 캐쉬의 성능을 향상시키기 위한 많은 블록 교체 기법들이 제안되었으며 이 중에서 작업 집합 (working set) 변화에 잘 적응하고 구현이 용이한 Least Recently Used (LRU) 블록 교체 기법이 널리 사용되고 있다. 그러나 LRU 블록 교체 기법은 블록들이 규칙적인 참조 패턴을 보이면서 순차 참조되거나 순환 참조될 때 이 규칙성을 적절히 이용하지 못해 성능이 저하되는 문제점을 가진다. 본 논문에서는 다중 응용 트레이스를 이용하여 LRU 블록 교체 기법의 문제점을 관찰하고, 이 문제점을 해결하는 통합된 형태의 효율적인 버퍼 관리 (Unified Buffer Management, 이하 UBM) 기법을 제안한다. UBM 기법은 순차 참조 및 순환 참조를 자동 검출하여 분리된 공간에 저장하고 이들 참조에 적합한 블록 교체 기법으로 이 공간을 관리한다. 또한 순차 참조와 순환 참조를 위한 공간과 나머지 참조를 위한 공간의 비율을 최적으로 할당하기 위해 온라인에서 수집된 정보를 이용하여 계산된 단위 공간 증가당 예상 버퍼 적중 증가율을 이용한다. 다중 응용 트레이스 기반 시뮬레이션 실험에서 UBM 기법의 버퍼 적중률은 LRU 블록 교체 기법에 비해 평균 12%, 최대 28%까지 향상된 결과를 보였다.

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Application of Digital Photogrammetry Technique in Geotechnical Engineering (지반공학에서의 수치영상기법의 활용)

  • Han, Jung-Geun;Hong, Ki-Kwon;Cho, Sam-Deok;Lee, Kwang-Wu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2007.09a
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    • pp.465-477
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    • 2007
  • Recently a number of research has been performed for the combination of new high technologies in order to find the solutions for various problems in civil engineering research field. Various high-tech measuring instruments have been applied to the geotechnical engineering field, and many attempts have also been performed for the more accurate measurements. Especially, the researches using image on the digital photogrammetry technique are gradually extending nowadays. The computer program developed using the digital photogrammetry technique and the case studies are explained and presented in this paper. Therefore, it could be considered that not only the measurement with high-accuracy but the disaster prevention should be available through the practical use of digital photogrammetry technique. The applicability would also be increased in the measurement of both the geotechnical engineering field as well as other research fields.

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Pullout Resistance of Steel Strip Reinforcement with Transverse Members using Large-scale Pullout Tests (대형인발시험을 이용한 수동지지저항 부재가 설치된 강재스트립 보강재의 인발저항 평가)

  • Lee, Kwang-Wu;Cho, Sam-Deok;Han, Jung-Geun;Hong, Ki-Kwon
    • Journal of the Korean Geosynthetics Society
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    • v.8 no.4
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    • pp.1-8
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    • 2009
  • In this study, the large-scale pullout tests are conducted to evaluate pullout resistance of steel strip reinforcement with transverse members. The test results clearly showed the passive effect by normal stress. This suggests that both friction resistance and passive resistance by normal stress should be taken into account in the evaluation of pullout resistance for design. Therefore, The evaluation results confirmed that the developed steel strip reinforcement with transverse members depend heavily on passive resistance by normal stress.

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A Novel PCR Primers HPU185 and HPL826 Based on 16S rRNA Gene for Detection of Helicobacter pylori

  • Kim, Jong-Bae;Kim, Geun-Hee;Kim, Hong;Jin, Hyun-Seok;Kim, Young-Sam;Ha, Soo-Hyun;Lee, Dong-Ki
    • The Journal of the Korean Society for Microbiology
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    • v.35 no.4
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    • pp.283-288
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    • 2000
  • The PCR primer set JW21-JW22 of Weiss et al. (19), which was reported to amplify a 139-bp fragment of the l6S rRNA gene of Helicobacter pylori, has been recently used for the detection of H. pylori in clinical specimens. However, when we applied JW21-JW22 PCR to other members of the genus Helicobacter and unrelated microorganisms, all of these bacteria produced a 139-bp PCR product. Therefore, we designed a novel primer set, HPU185-HPL826, which produced a 642-bp amplicon of the l6S rRNA gene of H. pylori. Then we further examined the specificity of the novel PCR assay using Southern blot hybridization with an internal probe, HPP225. The PCR assay described in this study was shown to be highly sensitive and specific only to the H. pylori 16S rRNA gene sequences.

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Feature Selection by Genetic Algorithm and Information Theory (유전자 알고리즘과 정보이론을 이용한 속성선택)

  • Cho, Jae-Hoon;Lee, Dae-Jong;Song, Chang-Kyu;Kim, Yong-Sam;Chun, Myung-Geun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.1
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    • pp.94-99
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    • 2008
  • In the pattern classification problem, feature selection is an important technique to improve performance of the classifiers. Particularly, in the case of classifying with a large number of features or variables, the accuracy of the classifier can be improved by using the relevant feature subset to remove the irrelevant, redundant, or noisy data. In this paper we propose a feature selection method using genetic algorithm and information theory. Experimental results show that this method can achieve better performance for pattern recognition problems than conventional ones.

Problem of Evaluation Methods on the Wall Facing-Geosynthetics Connection Strength and Its Improvement (전면 벽체-보강재 연결강도 평가방법의 문제점 및 개선 방향)

  • Hong, Ki-Kwon;Shin, Ju-Oek;Han, Jung-Geun;Cho, Sam-Deok;Lee, Kwang-Wu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.184-195
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    • 2008
  • The use of geosynthetics for the reinforced earth wall system has been increasing rapidly for a number of years. The connection strength between wall facing and geosynthetics should be evaluated in the design of geosynthetics. However, the connection strength is not often evaluate, exactly, and it causes problems such as deformation of the wall facing, local failure of the reinforced earth wall system, conservative design and so on. Therefore, the connection strength in the design of geosynthetics should be applied evaluation result by reasonable method. This study is evaluated connection strength using the typical design method, NCMA(1997) and FHWA(1996), in the field case. Then the results compared with the evaluation results of connection strength, which is suggested by Soong & Koener(1997). The analysis results confirmed that the connection strength for the design of geosynthetics should be evaluate using reasonable method with considering various factor, such as safety factor, installation and importance of construction.

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InAs/GaAs 양자점 태양전지에서 양자점 크기 및 온도에 따른 Photovoltage 효과

  • Yun, Su-Jin;So, Mo-Geun;Son, Chang-Won;Han, Im-Sik;No, Sam-Gyu;Lee, Sang-Jun;Kim, Jong-Su
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.228.1-228.1
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    • 2013
  • Photoreflectance (PR) 분광법은 비접촉, 비파괴적인 변조분광법으로서 반도체 표면 및 계면의 광학적 특성 연구에 많이 이용되고 있다. PR 신호의 Franz-Keldysh oscillation (FKO)으로부터 Molecular Beam Epitaxy (MBE) 방법으로 성장한 InAs/GaAs 양자점 태양전지 접합계면의 전기장을 조사하였다. InAs 양자점의 크기는 각각 1.7, 2.0, 2.5, 3.0 monolayer이며, p+-n-n+ 태양전지 구조의 표면으로부터 1.8 ${\mu}m$, 활성영역으로부터 약 1.1 ${\mu}m$ 위치에 삽입되어 있다. 여기광 세기가 큰 영역(1~200 $mW/cm^2$)에서 접합계면의 전기장으로부터 관측한 photovoltage 효과는 로그 스케일에서 대체로 선형적인 분포를 보였으며, 이를 계산결과와 비교 분석하였다. 또한, 양자점 크기 및 온도에 따른 photovoltage 효과는 활성영역에서 여기된 운반자의 양 및 양자점에 의한 전하트랩의 영향과 관련하여 비교 분석하였다.

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Anti-allergic effect of Cortex Mori (상백피(桑白皮)의 항알레르기성 효과)

  • Lee, Heon-Gu;Lee, Moo-Sam;Yang, Moon-Sik;Lee, Yang-Geun;Heo, Hoon;Son, Young-Taek;Jeon, Byung-Deuk
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.04a
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    • pp.176-176
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    • 1994
  • Moraceae comprise a large family of sixty genera and neary 1,400 specieses, including important groups such as Artocarpus, Morus, and Ficus. In particular, Morus(mulberry) is a small genus of tree and shrubs found in temperate and subtropical regions of the Northern hemishere and has been widely cultivated in China and Korea, In addition, the root bark of mulberry tree have been used as an antiphlogic, diuretic, and expectorant in white medicine, and the crude drug is known as "Sangbaikpi" in Korea. Recently, some papers have been published reporting the hypotensive effect, antiviral effect, antifungal effect, inhibitory effect of cAMP-phosphodiesterase, and anticancer effect of this extract. Little is known about that Cortex mori could have been an antiallergic effect. The purpose of this study was the development of an antiallergic agent with an antiallergic effect from Cortex mori. For this, several in vivo and in vitro experimental models were used. Results are 1) Cortex mori inhibited the compound 48/80-induced degranu-lation, histamine release and calcium uptake of rat peritoneal mast cells, 2) compound 48/80-induced anaphylactic shock and cutaneous reaction were significantly inhibited by pretreatment of Cortex mori, and 3) Cortex mori inhibited the ovalbumin-induced late astmatic reaction. From the above results it is suggested that Cortex mori has some substances with an antiallergic activity. Our final purpose of this study is to develope the new drug with an antiallergic activity from Cortex mori

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