최근 제안된 두 그룹서명기법의 암호분석

하등과(DengKe Ha),김기태(KiTae Kim),양대헌(DaeHun Nyang),이경희(KyungHee Lee) 한국정보보호학회 2010 정보보호학회논문지 Vol.20 No.5

연결불가능성(unlinkability)과 추적불가능성(traceability)은 그룹서명이 만족해야 하는 기본적인 요구사항이다. 본 논문에서 최근 Lee등과 Zhu등에 의해서 제안된 두 그룹 서명기법들이 갖는 취약점을 분석하였다. Lee등의 기법은 합법적인 서명자가 생성한 서명을 검증할 수 없는 설계상의 치명적인 문제를 갖고 있으며, 검증과정이 안고 있는 문제와 별개로 동일한 서명자가 생성한 서명을 항상 링크할 수 있음을 보인다. 또, Zhu등의 그룹서명기법에서 그룹의 관리자가 추적할 수 없도록 서명을 생성하는 것이 가능함을 보이고, 저자들의 주장과 달리, 그들의 기법이 전방향 안전성을 만족하지 않음을 보인다. Unlinkability and traceability are basic security requirements of a group signature scheme. In this paper, we analyze two recent group signature schemes, Lee et al.'s scheme and Zhu et al.'s scheme. We show that Lee et al.’s scheme does not work correctly. Further, it fails to meet unlinkability, that is, anyone who intercepts or receives group signatures are able to check if they are from the same signer. We also show that Zhu et al.'s scheme is unable to satisfy traceability, that is, a malicious group member can generate valid group signatures that cannot be opened. Moreover, once becoming group member, the malicious group member will never be revoked from group. Besides, Zhu et al.'s scheme fails to satisfy forward security, a requirement claimed by authors.

Tunnel Field Effect Transistor with Ferroelectric Gate Insulator

Lee, Kitae,Lee, Junil,Kim, Sihyun,Park, Euyhwan,Lee, Ryoongbin,Kim, Hyun-Min,Kim, Sangwan,Park, Byung-Gook American Scientific Publishers 2019 Journal of Nanoscience and Nanotechnology Vol.19 No.10

Biomechanical Analysis of Dolgaechagi in Taekwondo

Lee, Sungcheol,Hwang, Inseong,Lee, Kitae,Kim, Seungjae 연세대학교 대학원 1991 延世論叢 Vol.27 No.1

본 연구의 목적은 고급기술을 갖은 태권도 선수들에 의해 수행된 성공적인 돌개차기 기술과 관련된 운동학적 요인을 밝히는데 있다. 6명의 태권도 국가 대표팀 선수들을 대상으로 하여 촬영한 후 동작의 3차원 운동학적 자료를 얻었다. 분석된 변인들을 각 구간의 시간, 무게중심 변위, 차는 동작의 범위, 어깨와 �의 회전각속도, 차는다리의 무릎관절의 각속도와 차는 다리 분절의 선형속도, 각속도 등이었다. 이들 값들은 돌개차기 기술이 현재까지 분석된바 없기 때문에 다른 값들과 비교할 수 없었다. 그러므로 본 연구에서 얻어진 결과들은 돌개차기 기술의 운동학적 특성에 대한 적절한 표준으로 사용될 수 있을 것이다.

Evaluation of residual toxicity of hypochlorite-treated water using bioluminescent microbes and microalgae: Implications for ballast water management

Lee, Jung-Suk,Hong, Seongjin,Lee, Junghyun,Choi, Tae Seob,Rhie, Kitae,Khim, Jong Seong Elsevier 2019 Ecotoxicology and environmental safety Vol.167 No.-

<P><B>Abstract</B></P> <P>Total residual oxidants (TRO) in treated ballast water can produce various disinfection by-products (DBPs) depending on local conditions, such as salinity and organic matter content in water. Because TRO and DBPs are known to be harmful to aquatic organisms and humans, ecotoxicity tests have been proposed for screening the residual toxicity before discharging treated ballast water. In the present study, we aimed to address the decay rates and toxicity changes of TRO under various conditions in salinity, initial TRO concentrations, and residence time of TRO. In addition, the toxicological sensitivities of bioluminescent bacteria <I>Vibrio fischeri</I> and a commonly-used microalgae <I>Skeletonema costatum</I> relative to the residual toxicity of TRO and six selected DBPs were determined. Decay rate of TRO concentration increased as a function of salinity and was affected by the initial concentrations of TRO. Unexpectedly, significant bioluminescence inhibition was observed for hypochlorite-treated water at < 0.1 mg L<SUP>−1</SUP> TRO (expressed as Cl<SUB>2</SUB>), which is a lower concentration than the maximum allowable discharge concentration (MADC) to marine waters established by the International Maritime Organization (IMO). The ecotoxicological thresholds of no observed effective concentration and median effect concentration for all tested DBPs were about 3–10 times lower for <I>V. fischeri</I> than for <I>S. costatum</I>. The results indicate that bioluminescent microbes possess an ecologically-relevant sensitivity to both TRO and DBPs in ballast water. In general, bioassay using <I>V. fischeri</I> was potentially more effective than microalgae for screening the total toxicity of TRO and DBPs in treated ballast water, especially given that ballast water usually contains a highly variable and complex mixture of toxicants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Decay rates of TRO concentrations in water increased as a function of salinity. </LI> <LI> Significant toxicity was detected in the microbe (<I>V. fischeri</I>) at < 0.1 mg L<SUP>−1</SUP> of TRO. </LI> <LI> Within 24 h of exposure, microbial toxicity increased in hypochlorite-treated water. </LI> <LI> <I>V. fischeri</I> responded more sensitive to DBPs contamination than did for <I>S. costatum.</I> </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Target-Specific Gene Silencing of Layer-by-Layer Assembled Gold–Cysteamine/siRNA/PEI/HA Nanocomplex

Lee, Min-Young,Park, Sang-Jun,Park, Kitae,Kim, Ki Su,Lee, Hwiwon,Hahn, Sei Kwang American Chemical Society 2011 ACS NANO Vol.5 No.8

<P>Target-specific intracellular delivery of small interfering RNA (siRNA) is regarded as one of the most important technologies for the development of siRNA therapeutics. In this work, a cysteamine modified gold nanoparticles (AuCM)/siRNA/polyethyleneimine (PEI)/hyaluronic acid (HA) complex was successfully developed using a layer-by-layer method for target-specific intracellular delivery of siRNA by HA receptor mediated endocytosis. Atomic force microscopic and zeta potential analyses confirmed the formation of a AuCM/siRNA/PEI/HA complex having a particle size of <I>ca.</I> 37.3 nm and a negative surface charge of <I>ca.</I> −12 mV. With a negligible cytotoxicity, AuCM/siRNA/PEI/HA complex showed an excellent target-specific gene silencing efficiency of <I>ca.</I> 70% in the presence of 50 vol % serum, which was statistically much higher than that of siRNA/Lipofectamine 2000 complex. In the competitive binding tests with free HA, dark-field bioimaging and inductively coupled plasma–atomic emission spectroscopy confirmed the target-specific intracellular delivery of AuCM/siRNA/PEI/HA complex to B16F1 cells with HA receptors. Moreover, the systemic delivery of AuCM/siRNA/PEI/HA complex using apolipoprotein B (ApoB) siRNA as a model drug resulted in a significantly reduced ApoB mRNA level in the liver tissue. Taken together, AuCM/siRNA/PEI/HA complex was thought to be developed as target-specific siRNA therapeutics for the systemic treatment of various liver diseases.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-8/nn2017793/production/images/medium/nn-2011-017793_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn2017793'>ACS Electronic Supporting Info</A></P>

Analysis on Capacitance Characteristics in FE-GAA MOSFET

Kitae Lee,Sihyun Kim,Munhyeon Kim,Sangwan Kim,Byung-Gook Park 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6

Nonlinear Thomson Scattering for Attosecond X-ray Pulse Generation

Kitae Lee,Seong Hee Park,Young Uk Jeong 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.4

Coherent nonlinear Thomson scattering using a relativistic electron beam has been obtained and can be used to generate attosecond X-ray pulses. When the laser intensity becomes relativistic (>1018 W/cm2), an electron conducts relativistic oscillatory motion, causing radiation with a harmonic spectrum. Under a plane-wave approximation, an analytic formula to describe the coherent spectrum generated from an electron beam has been developed. This formula leads to a condition, under which the radiations scattered from different electrons in an electron beam might coherently add. We find that with an electron beam of a few tens of nanometers in length, an X-ray pulse with a pulse length of a few tens of attoseconds can be generated. Including the finite focal size of the laser pulse, we have estimated that a few tens of terawatts will be required to demonstrate coherent nonlinear Thomson scattering.

Gene Expression Analysis and Polymorphism Discovery to Investigate Drought Responsive System in Tropical Maize

( Kitae Song ),( Hyo Chul Kim ),( Kyung-hee Kim ),( Jun-cheol Moon ),( Jae Yoon Kim ),( Sang-kyu Lee ),( Byung-moo Lee ) 한국육종학회 2018 Plant Breeding and Biotechnology Vol.6 No.4

Maize has high food and industrial value, whereas has difficulties in research because of their complex and huge size genome. Nested association mapping (NAM) was constructed to better understand maize genetics. However, most studies were conducted using the reference genome B73, and only a few studies were conducted on tropical maize. Ki3, one of the founder lines of the NAM population, is a tropical maize. We analyzed the genetic characteristics of Ki3 by using RNA sequencing and bioinformatics tools for various genetic studies. As results, a total of 30,526 genes were expressed, and expression profile were constructed. A total of 1,558 genes were differentially expressed in response to drought stress, and 513 contigs of them come from de novo assemblies. In addition, high-density polymorphisms including 464,930 single nucleotide polymorphisms (SNPs), 21,872 multiple nucleotide polymorphisms (MNPs) and 93,313 insertions and deletions (InDels) were found compared to reference genome. Among them, 15.0 % of polymorphisms (87,838) were passed non-synonymous test which could alter amino acid sequences. The variants have 66,550 SNPs, 5,853 MNPs, and 14,801 InDels, also proportion of homozygous type was higher than heterozygous. These variants were found in a total of 15,643 genes. Of these genes, 637 genes were found as differentially expressed genes (DEGs) under drought stress. Our results provide a genome-wide analysis of differentially expressed genes and information of variants on expressed genes of tropical maize under drought stress. Further characterization of these changes in genetic regulation and genetic traits will be of great value for improvement of maize genetics.

Propagation of a Laser-Generated Shock Wave in a Metal Confined in Water

Lee Kitae,Lim C.H.,Kwon S.O. 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.1

The propagation of a laser-generated shock wave in a metal, which is confined in water, was investigated using a one-dimensional Lagrangian hydrodynamics code. This code deals with dynamics from the initial generation of a plasma by a laser-plasma interaction to the propagation of a high-pressure shock wave in a solid material. The simulation results show that the influence of the laser temporal shape on the shock wave propagation is weak once the laser fluence is kept constant. From Fabbro’s formula [R. Fabbro et al., J. Appl. Phys. 68, 775 (1990)], the generation of a shock wave at the front surface has been known to be affected mainly by the laser intensity, but the propagation of the shock wave inside a metal was found to be mainly influenced by the laser fluence. The impulse per unit area exerted on the metal could be a more practical parameter for applications to material hardening and is found to scale with the laser fluence.

Nonvolatile Memory (NVM) Operation of Tunnel Field-Effect Transistor (TFET) Using Ferroelectric HfO₂ Sidewall

Lee, Ryoongbin,Lee, Kitae,Kim, Sihyun,Kwon, Dae Woong,Kim, Sangwan,Park, Byung-Gook American Scientific Publishers 2019 Journal of Nanoscience and Nanotechnology Vol.19 No.10