• Title/Summary/Keyword: ID factor

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Secure ID-Based Key Agreement Protocol with Anonymity for Mobile Ad Hoc Networks (이동 애드혹 네트워크에서의 익명성을 제공하는 아이디 기반의 안전한 키 교환 프로토콜)

  • Park, Yo-Han;Park, Young-Ho;Moon, Sang-Jae
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.1
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    • pp.92-101
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    • 2012
  • Security support is a significant factor in ad hoc networks. Especially in dynamic topologies, key agreement with private key updating is essential in providing a secure system. And it is also necessary to protect the identities of individual nodes in wireless environments to avoid personal privacy problems. However, many of the existing key agreement schemes for ad hoc networks do not consider these issues concurrently. This paper proposes an anonymous ID-based private key update scheme and a key agreement scheme for mobile ad hoc networks. We also suggest a method of rekeying between different domains using service-coordinators. These schemes are secure against various attacks and are suitable for service-oriented mobile ad hoc networks.

The Heat Transfer and Pressure drop Characteristics of R7l8 in Small Diameter Tubes (세관내 액단상의 열전달과 압력강하에 관한 연구)

  • 김세웅;홍진우;손창효;노건상;오후규
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.11a
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    • pp.28-35
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    • 2001
  • The heat transfer and pressure drop characteristics of R718 flowing in smooth horizontal copper tubes with inner diameter of 3.36 mm, 5.35 mm, 6.54 mm and 8.12 mm were investigated. The test section is a counterflow heat exchanger with refrigerant flowing in the inner tube and water flowing in the annulus. Experiments were peformed for the flowing range of variables : Reynolds number (1000 to 20000), mass flow rate of brine (450 kg/h) and refrigerant temperature (5$0^{\circ}C$). The main results were summarized as follows : (1) The heat transfer coefficient of 3.36 mm ID was about 10% to 30% higher than that of 5.35 mm, 6.54 mm and 8.12 mm ID, and the heat transfer coefficients for small diameter. tubes are about 20% to 27% higher than these predicted by Gnielinski. The new correlation is proposed to predict the experimental data. (2) As a result of comparison with correlation prosed by Blasius. the deviation of the experimental data slightly increased as the tube diameter decreased. (3) The ratio of heat transfer to friction factor (j/f) correlated by all experimental data increased as the tube diameter decreased.

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Secure Private Key Revocation Scheme in Anonymous Cluster -Based MANETs

  • Park, YoHan;Park, YoungHo
    • Journal of Korea Multimedia Society
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    • v.18 no.4
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    • pp.499-505
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    • 2015
  • Security supports are a significant factor in the design of mobile ad hoc networks. In the dynamic topology where the node changes frequently, private key generation and revocation for newly joining and leaving nodes must be considered. In addition, the identities of individual nodes must be protected as well in mobile networks to avoid personal privacy concerns. This paper proposes ID-based private key revocation scheme and non-interactive key agreement scheme in anonymous MANETs. The proposed scheme provides the user privacy using pseudonyms and private key generation and revocation schemes with consideration of dynamic user changes. Therefore, our schemes can be applied in dynamic and privacy-preserving MANETs which are helpful to share multimedia data.

Interference between two dynamic cracks (동적 균열의 간섭)

  • 이억섭;최인성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.714-718
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    • 1996
  • The interference phenomenonof a dynamic crack propagation in a inclined DEN(double edge notched) specimen has been investigated by using the dynamic photoelasticity. One crack initiated by static loading is propagated dynamically and experiences a mixed mode condition(interference) as the crack approaches to the inclined edge notch. We use the overdeterministic least-square method to extract dynamic $K_{Id}$ K sub IId/and .sigma. $_{ox}$from the recorded dynamic photoelastic pattern surounding a running crack. The evaluated $K_{Id}$ $K_{IId}$and .sigma. $_{ox}$together with the crack propagation velocity estimate the dynamic crack interference phenomenonenonon

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Management Method for Private Key File of PKI using Container ID of USB memory (USB 메모리의 컨테이너ID를 이용한 PKI 기반의 개인키 파일의 안전한 관리 방안)

  • Kim, Seon-Joo;Joe, In-June
    • The Journal of the Korea Contents Association
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    • v.15 no.10
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    • pp.607-615
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    • 2015
  • Mosts user of internet and smart phone has certificate, and uses it when money transfer, stock trading, on-line shopping, etc. Mosts user stores certificate in a hard disk drive of PC, or the external storage medium. In particular, the certification agencies are encouraged for user to store certificate in external storage media such as USB memory rather than a hard disk drive. User think that the external storage medium is safe, but when it is connect to a PC, certificate may be copied easily, and can be exposed to hackers through malware or pharming site. Moreover, if a hacker knows the user's password, he can use user's certificate without restrictions. In this paper, we suggest secure management scheme of the private key file using a password of the encrypted private key file, and a USB Memory's hardware information. The private key file is protected safely even if the encrypted private key file is copied or exposed by a hacker. Also, if the password of the private key file is exposed, USB Memory's container ID, additional authentication factor keeps the private key file safe. Therefore, suggested scheme can improve the security of the external storage media for certificate.

Analysis of Long-Term Performance of Geogrids by Considering Interaction among Reduction Factors (감소계수 상호영향을 고려한 지오그리드의 장기성능 해석)

  • Jeon, Han-Yong;Kim, Yuan-Chun;Jang, Yeon-Soo
    • Journal of the Korean Geotechnical Society
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    • v.28 no.7
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    • pp.55-65
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    • 2012
  • Total reduction factor that is used when calculating allowable tensile strength of geogrids is made by multiplying the installation damage reduction factor ($RF_{ID}$), chemical degradation reduction factor ($RF_D$), and creep reduction factor ($RF_{CR}$) etc. In case of a model estimating allowable tensile strength considering reduction factor over the short-term tensile strength of geogrids, it has a limit of not considering interaction force between reduction factors. Junction strength comes to be reduced by installation damages or chemical degradation in the same way as tensile strength. Single junction test method cannot properly test damaged samples and shows large deviations as it does not consider scale effect. Besides, regarding calculating shear strength, no reasonable study on reduction factors was conducted yet. Therefore, in this study, reduction factors that may affect the long-term performance of geogrids were revaluated considering various conditions and accurate long-term allowable tensile strength was calculated considering interrelation between reduction factors. Creep results after installation damage and chemical resistance test showed lower value than calculated value according to GRI GG-4. After the installation damage test and the chemical resistance test, the reduction factor of junction strength was less than that of tensile strength. Shear strength before and after installation damage showed no change or increase.

Antioxidant and anti-gastritis effects of a mixture of Ipomoea batatas extract and Dioscorea japonica extract on an animal model by HCl/ethanol-induced gastritis (고구마와 참마 추출 혼합물의 항산화 활성 및 HCl/ethanol 투여로 유도된 위염 동물모델에서 위염 억제 효과)

  • Yun-seong Lee;Eun-Gyung Mun;Eun Ah Sim;Bo-Young Lee
    • Journal of Nutrition and Health
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    • v.57 no.4
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    • pp.389-402
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    • 2024
  • Propose: This study examined the antioxidant and anti-gastritis properties of a mixture comprising Ipomoea batatas (IB) extract and Dioscorea japonica (DJ) extract. Methods: The mixture of IB and DJ extracts was analyzed for its total flavonoid content (TFC), total polyphenol content (TPC), and radical scavenging activities. Gastric lesions were induced by treating rats with 1 mL of a solution containing 60% ethanol and 150 mM HCl. The rats were then divided into 5 groups: CON (normal control), HEC (treated with 150 mM HCl-60% ethanol and distilled water), IBE (treated with 150 mM HCl-60% ethanol and IB extract at 350 mg/kg body weight [BW]), ID30 (treated with 150 mM HCl-60% ethanol and a mixture of IB and DJ extracts in a 7:3 ratio at 350 mg/kg BW), and DJE (treated with 150 mM HCl-60% ethanol and DJ extract at 350 mg/kg BW). Results: The ID30 group exhibited significantly higher TFC, TPC, and radical scavenging activities than the groups treated with single extracts. This group also showed a notable decrease in the formation of gastric lesions and preservation of gastric wall mucus. In addition, the serum levels of the inflammatory marker tumor necrosis factor (TNF)-α were significantly lower in the ID30 group than in the HEC group. Conclusion: The antioxidants present in the ID30 mixture effectively reduced oxidative stress and reactive oxygen species, mitigating gastric mucosal irritation induced by alcohol and acid. Furthermore, the mixture inhibited gastric acid secretion and inflammatory marker expression, such as TNF-α, preventing tissue damage. These findings suggest that the ID30 mixture is a potential preventative treatment for gastritis.

Lessons learned from Operation Iraqi Freedom(OIF) for ROK forces (이라크전쟁의 군사적 교훈)

  • Mun, Gwang-Geon
    • Journal of National Security and Military Science
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    • s.1
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    • pp.71-111
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    • 2003
  • The key lessons of the very complex modern war can be dangerously misleading to the outsiders. The efforts trying to draw lessons learned from the Iraq War (OIF : Operation Iraqi Freedom) may be biased by the view of point by Americans, because most of war episodes have been come from the Western media coverage. More serious bias can be committed thanks to the differences of warfighting doctrines and military technology between US forces and ROK forces. However, OIF-fought allied commanders and outside military experts said this campaign exemplified 21st-century warfare: swift, agile and decisive, employing overpowering technology to bring relentless violence to bear in many places at once. Even though the campaign evolved differently than anticipated, allied forces regrouped and regained the initiative remarkably quickly, thanks in large part to a new command flexibility, tied to new technology that made possible the more rapid sharing of data. These factors permitted "new air-land dynamic". The things that compel that are good sensors networked with good intelligence disseminated through a robust networking system, which then yields speed. Speed turns out to be a very important factor for conducting "Rapid Decisive Operations" relied on joint "Mass of Effects". ROK forces facing the heaviest ground threat in the world may learn more from Cold War era-typed US Army 3rd Infantry Division (3ID), which operating considerably beyond existing doctrine. 3ID flew its personnel into Kuwait to meet up with equipment already located in the region as pre-positioned stock. During OIF, the division conducted continuous offensive operations over 230km deep battlespace for 21 days. The lessons learned for ROK army to prepare tomorrow's war may be found from 3ID in its training, command and control, task organization, firepower and battlespace management, and logistics.

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Effect of Cryptochlorogenic Acid Extracted from Fruits of Sorbus commixta on Osteoblast Differentiation (마가목 열매에서 추출한 Cryptochlorogenic Acid 처리에 의한 조골세포 분화 촉진 효능)

  • Kim, Kyeong-Min;Kim, Tae Hoon;Jang, Won-Gu
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.3
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    • pp.314-319
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    • 2017
  • Chlorogenic acid, a well-known polyphenol, and its derivatives, ester of caffeic acid on quinic acid moiety, are abundant in coffee, tea, fruits, and various vegetables. This study examined the effects of cryptochlorogenic acid (CCA) on osteoblast differentiation. CCA-induced mRNA expression levels of osteogenic genes in MC3T3E1 and C3H10T1/2 cells were determined by RT-PCR and qPCR. CCA regulated expression of key osteogenic genes in the early stage of differentiation, including distal-less homeobox 5 (Dlx5), DNA-binding protein inhibitor (Id1), and runt-related transcription factor 2 (Runx2). These results suggest that CCA may enhance osteoblast differentiation through expression of osteogenic genes such as Id1, Dlx5, and Runx2, especially in the early stage.