• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.70-72
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• 2005

최근들어 Radio Frequency Identification (RFID) 태그가 다수의 상품에 부착되고 절러 분야에 적용되기 시작했지만, 비용문제로 인해 인증이나 암호화 같은 보안기능은 고려하지 않고 있다. 보안 기능이 없는 RFID시스템은 개인정보 노굴, 불법 리더의 접근, 위조 태그의 남용과 같은 심각한 부작용을 초래하지만 현 단계에서는 보안기능을 적용하기가 쉽지않다. 절러 기술을 따르는 수동형 태그중 EPCglobal의 EPC Class 1과 Class 1 Generation 2(C1G2)는 산업계의 여러 분야에서 특히, supply-chain 모델에서 사실상 국제표준으로 여겨진다. EPC Class1 수준의 태그는 자체 밧데리를 가지지 않는 수동형 태그이고, 암호 프리미티브를 적용한 알고리즘이나 프로토콜은 제공하지 않는다. EPC Class1 과 EPC C1G2의 유일한 보안 대책으로는 태그를 영원히 동작하지 못하게 하는 Kill 기능이 있다. Kill을 수행한 태그는 RFID 태그로서의 의미가 사라진다. 본 논문에서는 Kill 기능에 대한 EPC Class1 시스템의 취약성을 보이고 또한, EPC C1G2 시스템에서 Kill 관점에서의 보안성을 분석한다.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1113-1116
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• 2005

최근들어 Radio Frequency Identification(RFID) 태그가 다수의 상품에 부착되고 여러 분야에 적용되기 시작했지만, 편리성이나 비용문제로 인해 인증과 암호화 같은 보안기능은 적용되지 않고있다. 보안 기능이 없는 RFID 시스템은 개인정보 노출, 불법 리더의 접근, 위조 태그의 남용과 같은 심각한 부작용을 초래하지만, 태그 자원의 제약으로 인해 보안기능을 적용하기가 쉽지않다. 현재 여러 기술을 따르는 RFID 시스템 중 EPCglobal 의 EPC Class 1 Generation 2(C1G2) 는 산업계의 여러 분야에서 특히, supply-chain 모델에서 사실상 국제표준으로 여겨진다. 본 논문에서는, RFID 보안 프로토콜 중 EPC C1G2 메커니즘의 Inventory 과정에서 태그가 리더를 인증하는 기법을 제안한다. C1G2 시스템에서는 인증되지 않은 리더의 태그 액세스가 가능한데, 이는 태그의 리더 인증으로서 차단될 수 있다. 또한, EPC C1G2 태그-리더 간의 상호인증 기법을 제안한다. 이 과정에서 태그 ID 는 노출되지 않고 전송되며, 태그 인증을 통해 태그 위변조를 방지할 수도 있다. 제안 메커니즘은 태그를 식별하는 절차에서 인증을 위해 프로토콜 패스 수의 증가가 없다. 다만 리더와 태그에서 Inventory 과정의 ACK command 와 태그의 reply 구현에 약간의 수정을 필요로 한다.

• Progress in Superconductivity and Cryogenics
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• v.26 no.1
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• pp.14-19
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• 2024

In this study, we explore the anisotropy of electron-phonon coupling (EPC) constant in epitaxially grown MgB₂ films on c-axis oriented Al₂O₃, examining its correlation with the critical temperature (T_c) and local structural disorder assessed through polarized Raman scattering. Analysis of the polarized Raman spectra reveals angle-dependent variations in the intensity of the phonon spectra. The Raman active mode originating from the boron plane, along with two additional phonon modes from the phonon density of states (PDOS) induced by lattice distortion, was distinctly observed. Persistent impurity scattering, likely attributed to oxygen diffusion, was noted at consistent frequencies across all measurement angles. The EPC values derived from the primary Raman active phonon do not significantly vary with changing observation angles, followed by that the T_c values calculated using the Allen and Dynes formula remain relatively constant across all polarization angles. Although the E_2g phonon mode plays a crucial role in the EPC mechanism, the determination of T_c values in MgB₂ involves not only electron-E_2g coupling but also contributions from other phonon modes.

• ETRI Journal
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• v.37 no.5
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• pp.929-939
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• 2015

Ultra-high-frequency radio-frequency identification (UHF RFID) is widely applied in different industries. The Frame Slotted ALOHA in EPC C1G2 suffers severe collisions that limit the efficiency of tag recognition. An efficient full-duplex anti-collision scheme is proposed to reduce the rate of collision by coordinating the transmitting process of CDMA UWB uplink and UHF downlink. The relevant mathematical models are built to analyze the performance of the proposed scheme. Through simulation, some important findings are gained. The maximum number of identified tags in one slot is g/e (g is the number of PN codes and e is Euler's constant) when the number of tags is equal to mg (m is the number of slots). Unlike the Frame Slotted ALOHA, even if the frame size is small and the number of tags is large, there aren't too many collisions if the number of PN codes is large enough. Our approach with 7-bit Gold codes, 15-bit Gold codes, or 31-bit Gold codes operates 1.4 times, 1.7 times, or 3 times faster than the CDMA Slotted ALOHA, respectively, and 14.5 times, 16.2 times, or 18.5 times faster than the EPC C1 G2 system, respectively. More than 2,000 tags can be processed within 300 ms in our approach.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.965-970
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• 2003

This study has been performed to develope a method for the simultaneous determination of 1,4-dioxane (DOX), epichlorohydrin (EPC), propylene chlorohydrin (PCH), ethylene chlorohydrin (ECH) and 1,3-dichloro-2-pro-panol (DCP) in polysorbates, chloline chloride, choline bitartrate, modified starch and spices by purge and trapgas chromatography. Experimental design was used to select a suitable trap by measuring the limit of detection (LOD) and to investigate the effect of temperature and salt of extraction, and the percentage of recovery in various matrix. The LOD of DOX, EPC, PCH, ECH and DCP were 1.38$\mu\textrm{g}$, 0.23$\mu\textrm{g}$, 3.30$\mu\textrm{g}$, 3.97$\mu\textrm{g}$, 20.43$\mu\textrm{g}$ respectively, by means of using Vorcarb 3000 trap with 5$0^{\circ}C$ sample sparger. Excluding EPC, the recoveries of target compounds were above 90% in all matrix. Target compounds in polysorbates (17), choline chloride (5), choline bitartrate (5), modified starch (8) and spices (25) were not detected. But 2.5 ppm of DOX was detected in Tween 80.

• Journal of fish pathology
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• v.11 no.2
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• pp.129-136
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• 1998

In March 1997, a new rhabdovirus was isolated from moribund cultured Japanese flounder Paralichthys olivaceus in sea water tank and cage culture systems in Kyung-Nam and Chun-Nam province, Korea. At temperature $15^{\circ}C$ the virus replicated and induced cytopathic effects (CPE), which progressed to eventual cytolysis, in susceptible cell lines, including RTG-2 and EPC. The CHES-214 cell line was refractory. Virus particles were bullet-shaped and measured $70nm{\times}100$ to 150 nm in size. The isolate was sensitive to pH 3, to diethyl ether, and to heat ($50^{\circ}C$ 5 min, $60^{\circ}C$ 1 min). Viral replication was not inhibited by $10^{-4}$ M 5-iododeoxyuridine. Virus infectivity was reduced by anti-HRV (8401-H) rabbit serum, but can not reduced by antisera against infectious hematopoietic necrosis virus (IHNV), chum salmon reovirus (CSV), retrovirus of salmonid (RVS) and infectious pancreatic necrosis virus (IPNV). HRV virus antigen was detected by fluorescent antibody test (FAT) in the cytoplasm of infected EPC cell. Purified isolates virions were composed of: polymerase (L), glycoprotein (G), nucleoprotein (N) and 2 matrix proteins (M1 and M2). Based upon their relative mobilities, the estimated molecular weights of the proteins were: L, 160 kDa; G, 55 kDa; N, 45 kDa; M1, 26 kDa; and M2, 22 kDa.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.191-192
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• 2007

This paper presents a 900MHz fractional-N frequency synthesizer for radio frequency identification (RFID) reader using $0.18{\mu}m$ standard CMOS process. The IC meets the EPC Class-1 Generation-2 and ISO-18000 Type-C standards. To minimize VCO pulling, the 900MHz VCO is generated by a 1.8GHz VCO followed by a frequency divider. The settling time of the synthesizer is less than $20{\mu}m$. The frequency synthesizer achieves the phase noise of -105.6dBc/Hz at 200kHz offset. The frequency synthesizer occupies an area of $1.8{\times}0.99mm^2$, and dissipates 8mA from a low supply voltage of 1.8V.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1765-1772
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• 2002

Three experiments were conducted to determine the feed processing method best suited for early and conventionallyweaned pigs, and to investigate the effects of different extrusion temperatures on ileal digestibility of amino acids in diets containing different protein sources. In exp.1, a total of 108 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 24 d of age and 7.60 kg average body weight) were alloted on the basis of sex, weight and ancestry to three treatments in a randomized complete block design. Feed processing methods used were mash (M), simple pellet (SP), and expanded pellet (EP). In exp. 2, a total of 96 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 14 d of age) were allotted on the basis of sex, weight, and ancestry to three treatments in a randomized complete block design. Diets were mash (M), expanded pellet (EP), and expanded pellet crumble (EPC). In exp. 3, a study was designed to investigate the effect of different extrusion temperatures (100, 120, and $140^{\circ}C$) over the control (untreated) on the ileal digestibility of amino acids in diets containing protein sources such as spray-dried plasma protein (SDPP), whey protein concentrate (WPC), and fish meal (FM). Results in exp.1 showed that ADG, ADFI and the F/G ratio of pigs fed the SP diet were improved (p<0.05) compared with those fed the M or the EP diets, but the digestibility of nutrients was not different (p>0.05) among the treatments. In exp. 2, pigs fed expanded pellet treatments (EP or EPC) had a significantly improved (p<0.05) F/G ratio compared to the pigs fed the M diet which was primarily attributed to the significant reduction (p<0.05) in ADFI, but the overall growth rate of pigs fed expanded pellet diets was not improved. In exp. 3, there was a significant interaction effect (p<0.05) between the extrusion temperature and protein source on the ileal digestibility of amino acids. With an extrusion temperature of $100^{\circ}C$, the ileal digestibility of Lys, Val, Gly and Ser was significantly lower in the diet containing WPC compared to the diet containing SDPP. Increasing the temperature to $120^{\circ}C$ led to significant differences (p<0.05) in the digestibility of Thr and Tyr between diets containing WPC and SDPP. Regardless of extrusion temperatures, the weaned pigs' diet containing either SDPP or FM had significantly higher Lys, Phe, Thr, Val, and Gly digestibility relative to the WPC diet. Results of the present study suggest that simple pelleting of diets containing protein sources such as whey protein concentrate, spray-dried plasma protein and fish meal would be better than the extruded or expanded pellet diets. Extruder or expander processing of weaned pigs' feed could reduce palatability and ileal digestibility of several amino acids and therefore may be responsible for a negative growth response in weaned pigs.

• ETRI Journal
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• v.30 no.6
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• pp.826-832
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• 2008

The metal-ferroelectric-metal (MFM) capacitor in the ferroelectric random access memory (FeRAM) embedded RFID chip is used in both the memory cell region and the peripheral analog and digital circuit area for capacitance parameter control. The capacitance value of the MFM capacitor is about 30 times larger than that of conventional capacitors, such as the poly-insulator-poly (PIP) capacitor and the metal-insulator-metal (MIM) capacitor. An MFM capacitor directly stacked over the analog and memory circuit region can share the layout area with the circuit region; thus, the chip size can be reduced by about 60%. The energy transformation efficiency using the MFM scheme is higher than that of the PIP scheme in RFID chips. The radio frequency operational signal properties using circuits with MFM capacitors are almost the same as or better than with PIP, MIM, and MOS capacitors. For the default value specification requirement, the default set cell is designed with an additional dummy cell.