• Title/Summary/Keyword: Gil-ho Kim

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Bayesian Model Selection in the Unbalanced Random Effect Model

  • Kim, Dal-Ho;Kang, Sang-Gil;Lee, Woo-Dong
    • Journal of the Korean Data and Information Science Society
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    • v.15 no.4
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    • pp.743-752
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    • 2004
  • In this paper, we develop the Bayesian model selection procedure using the reference prior for comparing two nested model such as the independent and intraclass models using the distance or divergence between the two as the basis of comparison. A suitable criterion for this is the power divergence measure as introduced by Cressie and Read(1984). Such a measure includes the Kullback -Liebler divergence measures and the Hellinger divergence measure as special cases. For this problem, the power divergence measure turns out to be a function solely of $\rho$, the intraclass correlation coefficient. Also, this function is convex, and the minimum is attained at $\rho=0$. We use reference prior for $\rho$. Due to the duality between hypothesis tests and set estimation, the hypothesis testing problem can also be solved by solving a corresponding set estimation problem. The present paper develops Bayesian method based on the Kullback-Liebler and Hellinger divergence measures, rejecting $H_0:\rho=0$ when the specified divergence measure exceeds some number d. This number d is so chosen that the resulting credible interval for the divergence measure has specified coverage probability $1-{\alpha}$. The length of such an interval is compared with the equal two-tailed credible interval and the HPD credible interval for $\rho$ with the same coverage probability which can also be inverted into acceptance regions of $H_0:\rho=0$. Example is considered where the HPD interval based on the one-at- a-time reference prior turns out to be the shortest credible interval having the same coverage probability.

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Study on Characteristics of 4H-SiC MOS Device with PECVD SiON Insulator (PECVD SiON 절연막을 이용한 4H-SiC MOS 소자 특성 연구)

  • Kim, Hyun-Seop;Lee, Jae-Gil;Lim, Jongtae;Cha, Ho-Young
    • Journal of IKEEE
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    • v.22 no.3
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    • pp.706-711
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    • 2018
  • In this work, we have investigated the characteristics of 4H-SiC metal-oxide-semiconductor (MOS) devices with silicon oxynitride (SiON) insulator using plasma enhanced chemical vapor deposition (PECVD). After post metallization annealing, the trap densities of the fabricated devices decreased significantly. In particular, the device annealed at $500^{\circ}C$ in forming gas ambient exhibited excellent MOS characteristics along with negligible hysteresis, which proved the potential of PECVD SiON as an alternative gate insulator for use in 4H-SiC MOS device.

Desulfurization of Biogas Using Micro Bubble in a Biogas Plant (미세버블을 이용한 바이오가스 탈황정제 연구)

  • Tak, Bong-Yul;Tak, Bong-Sik;Kim, Chan-Gyu;Min, Gil-Ho;Jang, Choon-Man
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.6
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    • pp.518-523
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    • 2013
  • This paper describes the reduction of a hydrogen sulfide ($H_2S$) generated from a biogas plant. Micro bubble system is adopted to supply air into the water in the reaction chamber, which can increase the contact area of the supplied air to the reserving water. Two stage reaction chambers having two reaction rooms are designed and manufactured to enhance the reduction rate of a hydrogen sulfide. Sodium hydroxide (NaOH) is also considered to get rid of a hydrogen sulfide. Air volume rate to the water in a reaction chamber is maintained between 0.5 and $1.0m^3/min$. Throughout experimental measurement of the concentration of a hydrogen sulfide by changing the volume of supplied air into the water, reduction rate of a hydrogen sulfide increases as air volume increases. Adding sodium hydroxide to the water with the air supply can reduce effectively a hydrogen sulfide up to 99.5% from biogas. It is noted that a hydrogen sulfide generated by a biogas plant can reduce by supplying micro bubble air and sodium hydroxide effectively.

Symmetry structured SPN block cipher algorithm (대칭구조 SPN 블록 암호 알고리즘)

  • Kim, Gil-Ho;Park, Chang-Soo;Cho, Gyeong-Yeon
    • Journal of Korea Multimedia Society
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    • v.11 no.8
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    • pp.1093-1100
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    • 2008
  • Feistel and SPN are the two main structures in designing a block cipher algorithm. Unlike Feistel, an SPN has an asymmetric structure in encryption and decryption. In this paper we propose an SPN algorithm which has a symmetric structure in encryption and decryption. The whole operations in our SPN algorithm are composed of the even numbers of N rounds where the first half of them, 1 to N/2, applies function and the last half of them, (N+1)/2 to N, employs inverse function. Symmetry layer is executed to create a symmetry block in between function layer and inverse function layer. AES encryption and decryption algorithm, whose safety is already proved, are exploited for function and inverse function, respectively. In order to be secure enough against the byte or word unit-based attacks, 32bit rotation and simple logical operations are performed in symmetry layer. Due to the simplicity of the proposed encryption and decryption algorithm in hardware configuration, the proposed algorithm is believed to construct a safe and efficient cipher in Smart Card and RFID environments where electronic chips are built in.

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Study for Block Cipher Operating Mode Using Counter (카운터를 사용한 블록암호 운영모드에 관한 연구)

  • Yang, Sang-Keun;Kim, Gil-Ho;Park, Chang-Soo;Cho, Gyeong-Yeon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.10a
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    • pp.243-246
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    • 2008
  • This thesis suggests block cipher operating mode using ASR(Arithmetic Shift Register). ASR is ratted arithmetic shift register which is sequence that is not 0 but initial value $A_0$ multiplies not 0 or 1 but free number D on $GF(2^n)$. This thesis proposes ASR mode which changes output multiplying d and Floating ASR mode which has same function but having strengthened stability altering d. If we use ASR's output as a counter, there's advantage that it has higher stability and better speed than CTR. Also, ASR mode and FASR mode have advantage of Random access which is not being functioned on CTR mode, they can be widely used to any part which Random access is needed.

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Corosolic acid ameliorates acute inflammation through inhibition of IRAK-1 phosphorylation in macrophages

  • Kim, Seung-Jae;Cha, Ji-Young;Kang, Hye Suk;Lee, Jae-Ho;Lee, Ji Yoon;Park, Jae-Hyung;Bae, Jae-Hoon;Song, Dae-Kyu;Im, Seung-Soon
    • BMB Reports
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    • v.49 no.5
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    • pp.276-281
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    • 2016
  • Corosolic acid (CA), a triterpenoid compound isolated from Lagerstroemia speciosa L. (Banaba) leaves, exerts anti-inflammatory effects by regulating phosphorylation of interleukin receptor- associated kinase (IRAK)-2 via the NF-κB cascade. However, the protective effect of CA against endotoxic shock has not been reported. LPS (200 ng/mL, 30 min) induced phosphorylation of IRAK-1 and treatment with CA (10 μM) significantly attenuated this effect. In addition, CA also reduced protein levels of NLRP3 and ASC which are the main components of the inflammasome in BMDMs. LPS-induced inflammasome assembly through activation of IRAK-1 was down-regulated by CA challenge. Treatment with Bay11-7082, an inhibitor of IκB-α, had no effect on CA-mediated inhibition of IRAK-1 activation, indicating that CA-mediated attenuation of IRAK-1 phosphorylation was independent of NF-κB signaling. These results demonstrate that CA ameliorates acute inflammation in mouse BMDMs and CA may be useful as a pharmacological agent to prevent acute inflammation.

An implementation of portable gamma ray detection platform using Cortex-A8 (Cortex-A8을 이용한 휴대용 감마선 검출 플랫폼 구현)

  • Seo, Jae-Gil;Lee, Yoon-Ho;Kim, Young-Kil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.4
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    • pp.1028-1033
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    • 2013
  • As safety and security systems of shipping logistics are reinforced all over the world, ubiquitous technology-based core technology for safety and security is developing to build the system of logistics security. It is feared that the logistics security system of Korea has a possibility to technically depend on developed countries in the futures. Because the essential skills and equipment to retain security of logistics are not developed. It is urgent to introduce a logistics security system that fully integrates the entire logistics segment in the future. Thus, the necessity of developing the portable radiation detector which can detect gamma-ray nuclide is increasing for reinforcing safety and security systems. In this paper, a research suggests the implementation of portable radiation detector platform using Cortex-A8.

SIRT1 Suppresses Activating Transcription Factor 4 (ATF4) Expression in Response to Proteasome Inhibition

  • Woo, Seon Rang;Park, Jeong-Eun;Kim, Yang Hyun;Ju, Yeun-Jin;Shin, Hyun-Jin;Joo, Hyun-Yoo;Park, Eun-Ran;Hong, Sung Hee;Park, Gil Hong;Lee, Kee-Ho
    • Journal of Microbiology and Biotechnology
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    • v.23 no.12
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    • pp.1785-1790
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    • 2013
  • The synthetic machinery of ATF4 (activating transcription factor 4) is activated in response to various stress conditions involved in nutrient restriction, endoplasmic reticulum homeostasis, and oxidation. Stress-induced inhibition of proteasome activity triggers the unfolded protein response and endoplasmic reticulum stress, where ATF4 is crucial for consequent biological events. In the current study, we showed that the $NAD^+$-dependent deacetylase, SIRT1, suppresses ATF4 synthesis during proteasome inhibition. SIRT1 depletion via transfection of specific siRNA into HeLa cells resulted in a significant increase in ATF4 protein, which was observed specifically in the presence of the proteasome inhibitor MG132. Consistent with SIRT1 depletion data, transient transfection of cells with SIRT1-overexpressing plasmid induced a decrease in the ATF4 protein level in the presence of MG132. Interestingly, however, ATF4 mRNA was not affected by SIRT1, even in the presence of MG132, indicating that SIRT1-induced suppression of ATF4 synthesis occurs under post-transcriptional control. Accordingly, we propose that SIRT1 serves as a negative regulator of ATF4 protein synthesis at the post-transcriptional level, which is observed during stress conditions, such as proteasome inhibition.

Comparative Study of Growth and Gonad Maturation in Diploid and Triploid Marine Medaka, Oryzias dancena

  • Park, In-Seok;Gil, Hyun Woo;Lee, Tae Ho;Nam, Yoon Kwon;Kim, Dong Soo
    • Development and Reproduction
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    • v.20 no.4
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    • pp.305-314
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    • 2016
  • The marine medaka, Oryzias dancena is a suitable sample as a laboratory animal because it has a small size and clearly distinguishes between female and male. Data on the growth and maturity of the diploid and triploid sea cucurbit species suitable for laboratory animals are very useful for studying other species. Triploidy was induced in the marine medaka by cold shock treatment ($0^{\circ}C$) of fertilized eggs for 45 min, applied two minutes after fertilization. The diploid and triploid male fish were larger than their female counterparts (P<0.05), and the concentrations of thyroid stimulating hormone (TSH) and thyroxine (T4) were higher in the induced triploids over 1 year (P<0.05). In both the diploid and tri-ploid groups the concentrations of TSH and T4 were higher in the male fish than in the females (P<0.05), while the testo-sterone and estradiol-$17{\beta}$ concentrations in the induced triploids were lower than in the diploids (P<0.05). The gonadosomatic index (GSI) of the triploid fish was lower than that for the diploids, and the GSI for females in each ploidy group were higher than that for the males. For both groups the GSI was highest at 4 months of age, and decreased thereafter to 12 months. Analysis of the gonads of one-year-old triploid fish suggested that the induction of triploidy probably causes sterility in this species; this effect was more apparent in females than in males.

(-)-Epigallocatechin Gallate Inhibits the Pacemaker Activity of Interstitial Cells of Cajal of Mouse Small Intestine

  • Kim, Kweon-Young;Choi, Soo-Jin;Jang, Hyuk-Jin;Zuo, Dong-Chuan;Shahi, Pawan Kumar;Parajuli, Shankar Prasad;Yeum, Cheol-Ho;Yoon, Pyung-Jin;Choi, Seok;Jun, Jae-Yeoul
    • The Korean Journal of Physiology and Pharmacology
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    • v.12 no.3
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    • pp.111-115
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    • 2008
  • The effects of (-)-epigallocatechin gallate (EGCG) on pacemaker activities of cultured interstitial cells of Cajal (ICC) from murine small intestine were investigated using whole-cell patch-clamp technique at $30^{\circ}C$ and $Ca^{2+}$ image analysis. ICC generated spontaneous pacemaker currents at a holding potential of -70 mV. The treatment of ICC with EGCG resulted in a dose-dependent decrease in the frequency and amplitude of pacemaker currents. SQ-22536, an adenylate cyclase inhibitor, and ODQ, a guanylate cyclase inhibitor, did not inhibit the effects of EGCG. EGCG-induced effects on pacemaker currents were not inhibited by glibenclamide, an ATP-sensitive $K^+$ channel blocker and TEA, a $Ca^{2+}$-activated $K^+$ channel blocker. Also, we found that EGCG inhibited the spontaneous $[Ca^{2+}]_i$ oscillations in cultured ICC. In conclusion, EGCG inhibited the pacemaker activity of ICC and reduced $[Ca^{2+}]_i$ oscillations by cAMP-, cGMP-, ATP-sensitive $K^+$ channel-independent manner.