• 한국통신학회논문지
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• 제41권3호
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• pp.298-300
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• 2016

본고에서는 중계 공격 성공확률을 낮추기 위해 RFID 리더가 무요청(void challenge)을 보내더라도 태그가 응답하는 거리 제한 프로토콜을 제안한다. Full challenge 비율에 따른 공격 성공 확률을 분석하고, 기존의 프로토콜과 비교 분석하여 제안 프로토콜의 공격 성공 확률이 낮음을 보인다.

• 한국어병학회지
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• 제24권3호
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• pp.269-278
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• 2011

Gene expression of two glyceraldehyde-3-phosphate dehydrogenase (GAPDH) paralogs was examined during Edwardsiella tarda challenge and heavy metal exposures in mud loach (Misgurnus mizolepis; Cypriniformes) kidney and spleen. Transcription of the two mud loach GAPDH paralogs (mlGAPDH-1 and mlGAPDH-2) was significantly modulated by these stimulatory challenges in an isoform-dependent manner. Based on the real-time RT-PCR analysis, the mlGAPDH-2 transcripts were more preferentially induced by E. tarda challenge, whereas the mlGAPDH-1 transcripts were proven to show more inducibility in response to heavy metal exposure using Cd, Cu, Mn and Zn at $5{\mu}M$. Their isoform-specific response patterns were closely in accordance with the TF binding profiles in promoter and intron-1 of the two mlGAPDH isoforms, in which the mlGAPDH-2 has more binding sites for immune-related transcription factors than mlGAPDH-1 while the mlGAPDH-1 possesses exclusively metal responsive elements in its intron. Collectively, the mlGAPDHs are potentially involved in cellular pathways independent of glycolysis and the two GAPDH paralogs might undergo functional diversification or subfunctionalization at least at the transcription level.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.696-706
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• 2011

The objective of this study was to characterize serum immunoglobulins and lymphocytes subpopulations in the peripheral blood mononuclear cells (PBMCs) of Holstein calves in response to lipopolysaccharide (LPS) challenge from Escherichia coli. Fourteen calves received subcutaneous injections of E. coli LPS at 10 weeks of age, and six calves were injected with saline as a control. The concentrations of total serum IgG and the relative amount of LPS-specific IgG in calves challenged with LPS were significantly higher (p<0.05) compared to control animals and LPS challenge significantly increased (p<0.05) the percentage of $CD5^+$ and $CD21^+$ T cells in PBMCs. Meanwhile, LPS challenge significantly increased (p<0.05, p<0.01) the percentage of $CD8^+$ and $CD25^+$ T cells in peripheral blood mononuclear cells (PBMC) at 7 and 14 Day-post LPS challenge (DPLC), respectively. The composition of $CD4^+CD25^+$ T cells and $CD8^+CD25^+$ T cells from calves challenged with LPS was also higher (p<0.05 and p = 0.562, respectively) than those of control calves at 14 DPLC. In conclusion, LPS challenge not only induces production of IgG with expression of B-cell immune response related cell surface molecules, but also stimulates activation of T-lymphocytes in PBMC. Our results suggest that LPS challenge in calves is a good model to elucidate cellular immune response against Gram-negative bacterial infections.

• 한국통신학회논문지
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• 제42권2호
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• pp.349-357
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• 2017

많은 웹 사이트들이 사용자가 패스워드를 분실하거나 온라인 결제를 진행하는 등의 상황에서 SMS(Short Message Service) 기반의 사용자 인증을 채택하고 있다. SMS 기반 인증에서 인증 서버는 텍스트를 평문으로 전송하기 때문에 공격자가 그 텍스트를 도청하거나 가로채면 다른 사람(피해자)인 것처럼 인증을 받을 수 있다. 본 논문에서는 사용자가 스마트폰을 지금, 어느 위치에서 소유하고 있는지를 인증하는 챌린지-응답(challenge-response) 형태의 인증 방식을 제안한다. 제안 방식은 서버가 보낸 챌린지, 사용자의 현재 위치정보, 스마트폰에 저장된 비밀 값을 모두 사용하여 응답을 생성한다. 그 결과로, 단순히 사용자가 받은 SMS 메시지를 어떤 가공도 없이 그대로 서버로 되돌리는 SMS 기반 인증에 비해, 제안 방식은 훨씬 더 안전하다. 제안 방식은 기존 SMS 기반 인증의 텍스트에 해당하는 응답의 입력과 더불어, 인증 과정의 시작을 위해 추가로 패스프레이즈(passphrase)의 입력을 요구하나, 추가 입력의 부담은 향상되는 보안성을 고려할 때 대부분의 사용자들이 감내할 수 있는 수준이라 판단한다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권12호
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• pp.1717-1724
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• 2004

The study was conducted to determine the effect of Salmonella typhymurium lipopolysaccharide (LPS) challenge on egg-laying performance, inflammatory response, zinc metabolism in layer fed diets supplemented with organic or inorganic zinc since 3-wk-old. The three dietary treatments were corn-soybean meal basal diet without supplemental zinc or with supplemental zinc at 60 mg/kg zinc from $ZnSO_4$ or zinc amino acid complex (ZnAA). At the age of 58 wk-old, twelve hens from each dietary treatment were allotted into two sub-groups. On day 1, 3, 5, 7 of the $58^{th}$ week of age, six birds of one sub-group were injected intraperitoneally (i.p.) with 2 ml LPS (1.0 $\ell$/ml) or sterile saline. Neither zinc source ${\times}$ immune challenge interaction nor zinc source effect on egg production performance was observed (p>0.05), LPS-challenge decreased egg production (p<0.04) and increased percentage of cracked eggs (p <0.01). With LPS challenged, the fever response of hens fed ZnAA peaked and subsided earlier than in hens fed $ZnSO_4$ or basal diet. Serum IL-1$\beta$ at 3 h was higher (p<0.01), but lower (p<0.001) at 12 h post-challenge with LPS in hens fed ZnAA than $ZnSO_4$. In salinetreated groups, serum IL 1$\beta$ was higher in hens fed ZnAA than the basal diet at 3 h post-injection (p<0.01). LPS-challenged birds had lower serum zinc and higher zinc sequestered in liver and spleen (p<0.001). In saline-treated birds, there was no difference in zinc concentration of serum, liver and spleen among different dietary treatments (p>0.05). Supplementation of 60 mg/kg zinc from either ZnAA or $ZnSO_4$ significantly (p<0.05) elevated metallothionein (MT) concentration in liver and spleen. MT concentration in liver of birds fed ZnAA diet was higher than in those fed $ZnSO_4$ diet (p<0.05). The magnitude of increase of hepatic and splenic MT due to LPS challenge was higher by supplementation of ZnAA than $ZnSO_4$. The results suggest that zinc amino acid complex enhanceed MT synthesis and zinc sequestered in liver and spleen and increased the sensitivity to immune response due to LPS challenge.

• Asian-Australasian Journal of Animal Sciences
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• 제16권4호
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• pp.541-548
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• 2003

The Immunoglobulin $IgG_1$ and $IgG_2$ isotype immune responses of domestic ruminants and mice to Cowdria. ruminantium live infection or by immunization with inactivated organisms were determined by the enzyme linked immunosorbent assay and Western blotting. Immunization of goats with inactivated elementary bodies (IEBs) led to a predominant $IgG_1$ isotype response. This indicated that a Th2 response was induced. After challenge, the IgG isotype responses were mixed whereby both $IgG_1$ and $IgG_2$ antibodies were detected. Two goats that survived virulent challenge had a predominant $IgG_2$ isotype response. In cattle live infection by natur l challenge or experiment led to a predominant $IgG_1$ isotype response. Immunization of cattle with IEBs however led to mixed IgG responses characterized by similar $IgG_1$ and $IgG_2$ ratios. In the mouse live infection led to a predominant $IgG_2$ isotype response. This indicated the mouse developed a true Th1 type cell mediated immune response when inoculated with live organisms. Immunization with inactivated organisms on the other hand led to a dominant $IgG_1$ response. It is evident from this work that the immune responses of ruminants and mice to C. ruminantium are different and that using mice as the experimental model for immune responses to Cowdria ruminantium. is not the appropriate.

• 한국임상수의학회지
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• 제15권1호
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• pp.36-40
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• 1998

This experiment was carried out in order to evaluate the immunomodulatory activity of levamisole (LMS) in 5. fgrjn challenged eels with different treatment regimens: 7-day LMS treatment before the challenge, 7-day LMS treatment started simultaneously with the challenge, 14-day treatment before and after the challenge. The antibacterial effect was activated in all treated groups, with the best being obtained in the simultaneously treated group. LMS stimulated the defense mechanisms of the eel as demonstrated by increase in the level of total protein, albumin, trypsin inhibitor capacity, lysozyme activity, antibody titers antibacterial activity and survival rate. These results suggest that antibacterial effects of LMS was achieved by not only non-specific immune response but also specific one in eel.

• Asian-Australasian Journal of Animal Sciences
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• 제22권9호
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• pp.1303-1310
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• 2009

Two experiments were conducted to determine the effect of dietary zinc level on growth performance and immune function in normal (Experiment 1) and immunologically challenged (Experiment 2) weanling pigs. Treatments consisted of the following: i) a corn-soybean meal basal diet containing 36.75 mg/kg total Zn, ii) basal diet+60 mg/kg added Zn as $ZnSO_{4}$, iii) basal diet+120 mg/kg added Zn as $ZnSO_{4}$. Each diet was fed to six pens of four pigs per pen (Exp. 1) or six pens of three pigs per pen (Exp. 2). In Exp. 1, the dietary zinc level had no effect on average daily growth (ADG), average daily feed intake (ADFI), or feed conversion ratio (FCR). Concentrations of tissue and serum zinc were not affected. Peripheral blood lymphocyte proliferation (PBLP) was not affected by dietary treatments. Supplementation of 120 mg/kg Zn decreased (p<0.05) the antibody response to bovine serum albumin (BSA) on d 7 compared with pigs fed the basal diet, but not on d 14. In Exp. 2, LPS challenge had no effect on ADG, ADFI and FCR in the entire trial (from d 0 to 21). LPS challenge significantly decreased ADG and ADFI (p<0.01) from d 7 to 14, but FCR was not affected. LPS challenge increased PBLP (p<0.05) and serum concentration of interleukin-1 (IL-1) (p<0.01), whereas the antibody response to BSA and serum concentration of interleukin-2 (IL-2) were not affected. Supplementation of Zn did not affect ADFI and FCR from d 7 to 14, but there was a trend for ADG to be enhanced with Zn supplementation (p<0.10). Supplementation of Zn tended to increase PBLP (p<0.10). Dietary treatment had no effect on the antibody response to BSA or concentrations of serum IL-1 and IL-2. Results indicate that the level of Zn recommended by NRC (1998) for weanling pigs was sufficient for optimal growth performance and immune responses. Zn requirements may be higher for pigs experiencing an acute phase response than for healthy pigs.

• International Journal of Computer Science & Network Security
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• 제23권12호
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• pp.81-90
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• 2023

Cloud computing is an emerging business model popularized during the last few years by the IT industry. Providing "Everything as a Service" has shifted many organizations to choose cloud-based services. However, some companies still fear shifting their data to the cloud due to issues related to the security and privacy. The paper suggests a novel Trust based Mutual Authentication Mechanism using Secret P-box based Mutual Authentication Mechanism (TbMAM-SPb) on the criticality of information. It uses a particular passcodes from one of the secret P-box to act as challenge to one party. The response is another passcode from other P-box. The mechanism is designed in a way that the response given by a party to a challenge is itself a new challenge for the other party. Access to data is provided after ensuring certain number of correct challenge-responses. The complexity can be dynamically updated on basis of criticality of the information and trust factor between the two parties. The communication is encrypted and time-stamped to avoid interceptions and reuse. Overall, it is good authentication mechanism without the use of expensive devices and participation of a trusted third party.

• 정보보호학회논문지
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• 제12권4호
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• pp.67-76
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• 2002

분산 네트워크 환경에서 커버로스는 사용자와 응용 서버 사이에 인증을 위해서 대칭키를 사용하고 있으며 다른 영역의 시스템을 신뢰할 것을 가정하고 있다. 본 논문에서는 기존의 커버로스에 공개키/개인키를 적용하여 효율적이고 강력한 인증 메커니즘을 설계하였다. 제안하고 있는 메커니즘에서는 사용자 인증을 위해 미리 정해진 long-term 키와 공개키를 통해 교환한 랜덤 수에 MAC 알고리즘을 적용하여 암호화에 사용하는 세션키 값을 매번 바꾸어주기 때문에 안전성을 높였다. 또한, 영역간의 신뢰성을 높이기 위해 전자 서명 기반의 시도-응답(challenge-response) 기법을 통한 상호 인증 방법을 사용하고 있으며, 인증 절차를 간소화하여 사용하는 키의 수를 줄였다.