레진주입 수리법으로 수리된 복합재 구조의 기계적 특성 평가

곽병수(Byeong-su Kwak),정기원(Gi-Won Jung),권진회(Jin-Hwe Kweon) 한국항공우주학회 2018 한국항공우주학회 학술발표회 논문집 Vol.2018 No.11

새로운 형상의 복합재 샌드위치 체결부 구조의 파손거동 연구

곽병수 ( Byeong-su Kwak ),김홍일 ( Hong-il Kim ),동승진 ( Seung-jin Dong ),최진호 ( Jin-ho Choi ),권진회 ( Jin-hwe Kweon ) 한국복합재료학회 2016 Composites research Vol.29 No.4

본 논문에서는 두께와 재료의 구성이 변하는 복잡한 형상의 복합재 샌드위치 구조의 파손 거동을 연구하였다. 구조물은 두께가 일정한 알루미늄 하니콤 코어 샌드위치 판넬이, 두께가 줄어드는 폼코어 샌드위치 천이부를 거쳐, 최종적으로는 면재와 면재가 만나 단순 적층판을 이루면서 다른 구조물에 체결되는 형상을 갖는다. 하중은 인장 및 압축하중의 형태로 가해지며 각 3개씩 총 6개 시편에 대한 시험을 수행하였다. 시험 결과 압축시험의 경우 재료불연속선을 따른 면재의 파손에 취약하며, 재료불연속선을 따른 파손을 피할 수 있는 경우 알루미늄 코어와 카본 면재의 디본딩에 의한 파손이 나타남을 알 수 있었다. 파손하중은 디본딩에 의한 파손까지 견디는 경우가 약 16% 높게 나타났다. 인장시험의 경우 파손모드는, 곡률부를 갖는 복합재 구조물에서 가장 취약한 부분인, 플랜지와 웹이 만나는 곡률부의 층간분리 파손이 주를 이루었다. 파손하중은 압축하중이 인장하중에 비하여 약 7배 가량 높은 것으로 나타났다. 따라서 본 구조물은 주로 압축하중을 견디기 위한 목적의 구조물에 적용하여야 할 것으로 보인다. The failure of composite sandwich structures with thickness and material variation was studied. The main body of the structure is sandwich plate made of the carbon composite face and Aluminum honeycomb core. It is connected with composite laminated flange without core through transition region of tapered sandwich panel with foam core. Tension and compression tests were conducted for the total of 6 panels, 3 for each. Test results showed that the panels under compression are vulnerable to the face failure along the material discontinuity line between two different cores. However the failure load of which panel does not show such failure can carry 16% more load and fails in honeycomb core and face debonding. For the tensile load, the extensive delamination failure was observed at the corner radius which connects the panel and the flange. The average failure load for compression is about 7 times the tensile failure load. Accordingly, these sandwich structures should be applied to the components that endure the compressive loadings.

안전성을 보완한 ID기반 signcryption 기법

곽병옥(Byeong-Ok Kwak),정윤수(Yoon-Su Jeong),이상호(Sang-Ho Lee) 한국컴퓨터정보학회 2006 韓國컴퓨터情報學會論文誌 Vol.11 No.2

Zheng이 제안한 Signcryption 기법은 전자 서명과 대칭키 암호화를 논리적으로 한 단계에 수행함으로써 기존의 서명 후 암호화 기법들에서 요구되는 계산비용보다 적은 비용을 가지는 새로운 암호학적인 기법이다. 현재까지 제안되어 온 Signcryption 기법들에서는 송신 부인이 발생하여 제3자가 이를 검증해야 할 경우 수신측의 비밀키 노출이 불가피하였다. 이 문제를 해결하기 위해 이 논문에서는 익명성과 Unlinkability를 지원하는 다목적의 ID기반 Signcryption기법을 제안한다. 제안된 기법은 Weil-pairing을 암호화에 이용하면서 random oracle 모델의 안전성을 유지하고, 결정적 쌍선형 Diffie-Hellman 의미론적 보안의 형식적 증명을 따르기 때문에 기존 Signcryption 기법들보다 안전하면서 효율적이다. Zheng’s signcryption scheme is a new encryptical scheme of which can save more expense than those of the current signature encryption by using digital signature and symmetric key encryption logically. The current signcryption schemes have a problem that is to be exposed the secret key of the receiver in the case of checking repudiation of origin by the third party. To solve this problem, a solution suggested in this paper is to use multi-purpose ID-based signcryption scheme with anonymity and unlinkability. This solution is safe and more efficient than current signcryption schemes because the suggested scheme keeps the security of the random oracle model as using Weil-pairing in encryption, and follows a formal proof of semantic security of the decisional Diffie-Hellman problem.

Characteristics of Cucumber mosaic virus isolated from Zea mays in Korea

김미경,Byeong-Jin Cha,Hae-Ryun Kwak,Su Heon Lee,김정수,김국형,차병진 한국식물병리학회 2011 Plant Pathology Journal Vol.27 No.4

A virus causing mottle and stunt symptom on Zea mays was observed around Ulleng-do, Korea and identified as Cucumber mosaic virus (CMV-ZM) based upon biological,serological, and molecular characteristics. In host range studies, the CMV-ZM isolate produced local lesions on Datura stramonium, Vigna unguiculata,Cucurbita moschata, Chenopodium amaranticolor, Ch. quinoa, whereas this isolate produced systemic mosaic on Nicotiana tabacum cv. ‘Xanthi-nc’, Capsicum annuum,Solanum lycopersicum, Solanum melongena, Cucurbita pepo, and Z. mays. In addition, chlorotic local rings on inoculated leaves along with severe mosaic, malformation,and fern leaf symptoms on upper systemic leaves were shown in N. glutinosa plants. Complete nucleotide sequences of each genomic RNA segment was determined and compared to those of the other CMV strains. Comparison of the nucleotide sequence of 1a open reading frame (ORF) revealed approximately 89.2–92.4% sequence identity with each CMV subgroup IA and IB strain, while showing only 78% sequence identity with CMV subgroup II. Nucleotide sequence analysis of RNA2 ORFs revealed 85.3–97.6% sequence identity with subgroup I. In ORFs of RNA3, levels of nucleotide sequence identities were higher than 92–99.2% with CMV subgroup I and lower than 82% with CMV isolates of subgroup II. These results suggest that CMV-ZM isolate is more closely related to subgroup I than subgroup II and therefore, CMV-ZM isolate might be classified into as CMV subgroup I based on biological and molecular analysis.

공기살균 시스템 적용 팽이버섯 재배사 개발

유병기 ( Byeong-kee Yu ),이현동 ( Hyun-dong Lee ),김태헌 ( Te-heon Kim ),허정욱 ( Jeong-wook Heo ),곽강수 ( Kang-su Kwak ),이승철 ( Seung-chul Lee ),서다솜 ( Da-som Seo ),김세리 ( Se-ri Kim ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1

버섯은 해외로 수출 되고 있는 농산품이며 ‘19년 기준 팽이버섯은 전체 버섯류 수출의 41.8%를 차지하고 있다. 국내 농가에서는 백색계 팽이버섯 품종을 주로 재배하고 있으며 수확 면적은 ‘19년 기준 34ha, 생산량은 31,818톤이며 수출량은 13,143톤으로 전체 생산량의 약 41%가 수출되고 있다. 팽이버섯의 주요 수출국은 미국, 호주, 캐나다, 인도네시아, 네덜란드 이며 미국에는 ’19년 기준 5,528톤으로 가장 많은 물량을 소비하고 있다. 국내에서는 팽이버섯을 가열 조리하여 섭취하여 식중독 발생이 없으나, 국외의 경우 샐러드형태의 생식용으로 섭취하고 있어 Listeria균에 의한 식중독 사례가 ‘16년 11월~’19년 12월 17개주에서 보고되었고 ‘20년 CDC 조사 후 국내 3개 업체제품을 리콜 조치하였다. 본 연구에서는 수출용 팽이버섯 재배사의 Listeria 균 억제를 위한 공기 살균 장치를 부착한 파일럿 재배사를 제작하였고, 팽이버섯 재배에 사용되는 소재를 대상으로 살균 실험을 수행 하였다. 파일럿 버섯 재배사는 우레탄단열 압축 패널(열전도율 0.03W/㎡)을 사용하여 1.8×1.8×2.0m 크기로 제작하였다. 내부 온습도 조절은 공기열 히트펌프를 장착하여 냉각과 가온으로 온도 조절 가능한 복열식 시스템을 적용 하였다. 파일럿 재배사 내부의 공기를 살균하기 위하여 이온클러스터 AIO-Ⅰ(제조사: 수도프리미엄엔지니어링, 한국)를 부착하였고, 생육 단계 조건인 6.5℃, 습도 75% 조건에서 권지(병재배 소재), 칼라강판, 아연도금강판(재배사 소재)에 대하여 Listeria innocua를 접종하여 살균 실험을 수행하였다. 시험방법은 각 소재 2cm×5cm에 균을 도포, 2시간 건조 후 증류수, 알코올, 공기살균장치의 3가지로 각각 6시간 처리 후 균을 분리하여 선택성 고체배지에 도말 증식후 코로니를 측정하였다. 각 처리에서 알코올분무처리의 경우는 모든 처리에서 균이 검출되지 않았으며, 균접종 후 2시간 건조 후 시료인 블랭크처리보다 증류수 처리구에서는 2.4~20.0%로 균이 감소되는 것으로 나타났으며 증류수처리대비 이온클러스터 살균장치에서는 0.65~18.6%로 감소되는 것으로 나타나 이온클러스터의 살균효과가 있는 것으로 판단된다.

QR코드를 이용한 스마트폰 기반 도서 대출 시스템 구현

오병희(Byeong-Hui Oh),곽경수(Gyeong-Su Kwak),이인수(In-Soo Lee) 한국정보기술학회 2015 Proceedings of KIIT Conference Vol.2015 No.6

프레스공정시스템에서 유도전동기 상태모니터링을 위한 스마트 고장진단시스템 구현

곽경수(Gyeong-Su Kwak),오병희(Byeong-Hui Oh),이인수(In-Soo Lee) 한국정보기술학회 2015 Proceedings of KIIT Conference Vol.2015 No.6

Characteristics of Cucumber mosaic virus Infecting Zucchini in Korea

Kim, Mi-Kyeong,Kwak, Hae-Ryun,Jeong, Seon-Gi,Ko, Sug-Ju,Lee, Su-Heon,Kim, Jeong-Soo,Kim, Kook-Hyung,Choi, Jang-Kyung,Choi, Hong-Soo,Cha, Byeong-Jin The Korean Society of Plant Pathology 2010 Plant Pathology Journal Vol.26 No.2

A virus causing stunt, yellowing, severe mosaic, malformation symptoms on leaves and uneven development and malformation on fruits of zucchini was prevalent around Goseong, Gyeongsangnam-do, Korea. A survey conducted (2004) in the Goseong area revealed about 20% virus infection rate. The disease causative identified as Cucumber mosaic virus (CMV-Z1) was further characterized. The isolate induces mosaic symptoms on Cucumis sativus, while severe mosaic, stunt and malformation on C. pepo. Thin section analyses have shown that virus inclusions are formed in the cuticle layers as well as epidermal, parenchyma and collenchymas cells in virus-infected Nicotiana tabacum. CMV-Z1 isolate induced specific cytoplasmic inclusion bodies such as irregular clumps (IC), crystal (Cr) and irregular chloroplasts (ICh). IC was made up of virus particles interspersed with a darkly stained amorphous material and found both in the cytoplasm and vacuoles, whereas ICh and Cr were rarely found in the vacuoles. The genome of CMV-Z1 RNA-1 consists of 3359 nucleotide (nt) encoding 1a protein of 993 amino acids (aa). The CMV-Z1 RNA-2 was 3050 nt in length containing 2a (857 aa) and 2b (110 aa), while RNA-3 encoding 3a movement protein (279 aa) and coat protein (218 aa) was 2215 nt in length. Phylogenetic analyses of nucleotide sequences of CMV-Z1 isolate appeared it is more closely related to subgroup IA than to subgroup IB or II.

First Report of Cucumber mosaic virus Infecting Pinewood Coneflower (Rudbeckia bicolor) in Korea

Kim, Mi-Kyeong,Kwak, Hae-Ryun,Ko, Sug-Ju,Lee, Su-Heon,Kim, Jeong-Soo,Kim, Kook-Hyung,Cha, Byeong-Jin,Choi, Hong-Soo The Korean Society of Plant Pathology 2010 Plant Pathology Journal Vol.26 No.1

A virus isolate causing symptoms of yellow mosaic, fern leaves, malformation and plant necrosis on Rudbeckia bicolor was prevalent around Pyeongchang area in Korea. The causal virus was identified as Cucumber mosaic virus (CMV) using characteristics from biological, serological and molecular analyses and named as CMV-Rb. CMV-Rb caused mosaic on Nicotiana benthamiana, N. tabacum, Capsicum annuum, and Lycopersicon esculentum. However, typical local lesions did not develop on inoculated Pisum sativum, Cucurbita moschata, Datura stramonium and Tetragonia expansa plants. Full-length genome sequences of CMV-Rb RNAs 1, 2 and 3 were obtained using 12 primer pairs by RT-PCR analysis. The genome of CMV-Rb RNA segments 1, 2, and 3 consists of 3363nt, 3049nt, and 2214nt in length, respectively. In order to ascertain their taxonomic identity, nucleotide and the deduced amino acid sequence analyses RNAs 1, 2 and 3 of CMV-Rb isolates were conducted with previously reported sequences of CMV strains and/or isolates. CMV-Rb RNAs showed about 90 to 99% sequence identity to those of subgroup I strains suggesting that CMV-Rb is more closely related to CMV isolates belong to subgroup I. To our knowledge, this is the first report of CMV on Rudbeckia bicolor in Korea.

Isolation and Characterization of Pepper mottle virus Infecting Tomato in Korea

Kim, Mi-Kyeong,Kwak, Hae-Ryun,Han, Jung-Heon,Ko, Sug-Ju,Lee, Su-Heon,Park, Jin-Woo,Jonson, Miranda Gilda,Kim, Kook-Hyung,Kim, Jeong-Soo,Choi, Hong-Soo,Cha, Byeong-Jin The Korean Society of Plant Pathology 2008 Plant Pathology Journal Vol.24 No.2

A peculiar virus-like disease of tomato showing yellow mosaic and necrotic spots on leaves and necrosis on veins, petioles and stems was observed at the Tomato Experimental Station (TES), Buyeo, Chungcheongnamdo, Korea. The disease incidence at TES fields ranged from 21 to 35% infecting different tomato cultivars. For this reason, to identify the virus infecting tomato and to characterize the virus based on biology, serology, cytology and at molecular level. Here, leaf samples were randomly collected from different infected tomato cultivars at TES fields and greenhouses and tested by ELISA using Pepper mottle virus (PePMoV) and Tomato mosaic virus (ToMV) antisera. Infected saps were mechanically inoculated in different host plants to test for pathogenicity, symptomatology and host ranges. Infected tissues and ultrathin sections were examined by electron microscopy. Finally, putative coat protein and 3'-untranslated region (CP/3'-UTR) fragment was amplified and cloned for sequence determination and analyzed its genetic relationship to existing PepMoV and PVY sequences at the Genbank. Results showed 69% of the samples were positive with PepMoV, 13% with ToMV and 19 % were doubly infected with PepMoV and ToMV. Symptoms greatly varied from different host plants inoculated with tomato leaf sap infected with PepMoV alone and discussed in detailed in this paper. Electron microscopy from infected tissues showed filamentous particles of 720-750nm in length, a typical morphology and size of PepMoV. In addition, cylindrical inclusion bodies, pinwheels, scrolls and laminates with masses of fibrillar inclusions were also found in ultrathin sections. Alignment of the sequences of the CP/3'-UTR revealed >96% sequence identity with PepMoV and only <61% with PVY. Taken together, all these evidences presented clearly indicated that the causal agent infecting tomato at TES was PepMoV and we designated this PepMoV infecting tomato as Tom-sd2 strain in this study.