• 제목/요약/키워드: J.S.P.

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Improved Breakdown Voltage Characteristics of $In_{0.5}Ga_{0.5}P/In_{0.22}Ga_{0.78}As/GaAs$ p-HEMT with an Oxidized GaAs Gate

  • I-H. Kang;Lee, J-W.;S-J. Kang;S-J. Jo;S-K. In;H-J. Song;Kim, J-H.;J-I. Song
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제3권2호
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    • pp.63-68
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    • 2003
  • The DC and RF characteristics of $In_{0.5}Ga_{0.5}P/In_{0.22}Ga_{0.78}As/GaAs$ p-HEMTs with a gate oxide layer of various thicknesses ($50{\;}{\AA},{\;}300{\;}{\AA}$) were investigated and compared with those of a Schottky-gate p-HEMT without the gate oxide layer. A prominent improvement in the breakdown voltage characteristics were observed for a p-HEMT having a gate oxide layer, which was implemented by using a liquid phase oxidation technique. The on-state breakdown voltage of the p-HEMT having the oxide layer of $50{\;}{\AA}$was ~2.3 times greater than that of a Schottky-gate p-HEMT. However, the p-HEMT having the gate oxide layer of $300{\;}{\AA}$ suffered from a poor gate-control capability due to the drain induced barrier lowering (DIBL) resulting from the thick gate oxide inspite of the lower gate leakage current and the higher on-state breakdown voltage. The results for a primitive p-HEMT having the gate oxide layer without any optimization of the structure and the process indicate the potential of p-HEMT having the gate oxide layer for high-power applications.

비평활 발전비용함수를 가진 동적 경제급전문제의 교환 최적화 (A Swap Optimization for Dynamic Economic Dispatch Problem with Non-smooth Function)

  • 이상운
    • 한국컴퓨터정보학회논문지
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    • 제17권11호
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    • pp.189-196
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    • 2012
  • 본 논문은 동적 경제급전의 최적화 문제를 풀기 위해 교환 알고리즘을 제안하였다. 제안된 알고리즘은 첫 번째로, 발전단가 $C_i^{max}/P_i^{max}$가 비싼 발전기는 가동을 중지시키는 개념을 도입하여 총 요구량 $P_d$와 총 발전량 ${\Sigma}P_i$의 균형을 맞추었다. 다음으로 발전량을 $P_i=P_i{\pm}{\Delta}$, (${\Delta}$=1.0, 0.1, 0.01, 0.001)에 대해 $_{max}[F(P_i)-F(P_i-{\Delta})]$ > $_{min}[F(P_j+{\Delta})-F(P_j)]$, $i{\neq}j$이면 $P_i=P_i-{\Delta}$, $P_j=P_j+{\Delta}$로 발전량을 교환하는 방법을 적용하였다. 동적 경제급전 문제의 시험사례에 제안된 알고리즘을 적용한 결과 기존의 휴리스틱 알고리즘 최적화 발전비용을 크기 감소시켜 경제적인 이익을 극대화 시켰다.

THE MINIMAL FREE RESOLUTION OF CERTAIN DETERMINANTAL IDEA

  • CHOI, EUN-J.;KIM, YOUNG-H.;KO, HYOUNG-J.;WON, SEOUNG-J.
    • 대한수학회논문집
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    • 제20권2호
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    • pp.275-290
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    • 2005
  • Let $S\;=\;R[\chi_{ij}\mid1\;{\le}\;i\;{\le}\;m,\;1\;{\le}\;j\;{\le}\;n]$ be the polynomial ring over a noetherian commutative ring R and $I_p$ be the determinantal ideal generated by the $p\;\times\;p$ minors of the generic matrix $(\chi_{ij})(1{\le}P{\le}min(m,n))$. We describe a minimal free resolution of $S/I_{p}$, in the case m = n = p + 2 over $\mathbb{Z}$.

Compound Source MBE를 이용한 InGaP/InGaAs p-HEMT 구조의 성장 및 특성 분석 (Growth and Characterization of InGaP/InGaAs p-HEMI Using Compound Source MBE)

  • Kim, J.H.;S.J. Kang;S.J. Jo;J.D. Song;Lee, Y.T.;J.I. Song
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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    • pp.16-19
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    • 2000
  • DC and low frequency noise characteristics of InGaP/InGaAs pseudomorphic HEMTs (p-HEMTs) grown by compound source MBE are investigated for temperature range of 150K to 370K. Equivalent input noise spectra( $S_{iv}$ ) were measured as a function of frequency and temperature. $S_{iv}$ was measured to be 3.4 $\times$ 10$^{-12}$ $V^2$/ Hz at 1kHz for 1.3 X 50${\mu}{\textrm}{m}$$^2$InGaP/InGaAs p-HEMT at room temperature. Measurements of the low-frequency noise spectra of the p-HEMT as a function of temperature show that the trap with an activation energy level around 0.589 eV is a dominant trap that accounts for the low-frequency noise behavior of the device. The normalized extrinsic gm frequency dispersion of the p-HEMT. was as low as 2.5% at room temperature, indicating that the device has well-behaved low-frequency noise characteristics. Sub-micron (0.25 $\times$ 50${\mu}{\textrm}{m}$$^2$) gate p-HEMT showed $f_{T}$ and $f_{max}$ of 40GHz and 108GHz, respectively.y.y.

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ON THE SCALED INVERSE OF (xi - xj) MODULO CYCLOTOMIC POLYNOMIAL OF THE FORM Φps (x) OR Φpsqt (x)

  • Cheon, Jung Hee;Kim, Dongwoo;Kim, Duhyeong;Lee, Keewoo
    • 대한수학회지
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    • 제59권3호
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    • pp.621-634
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    • 2022
  • The scaled inverse of a nonzero element a(x) ∈ ℤ[x]/f(x), where f(x) is an irreducible polynomial over ℤ, is the element b(x) ∈ ℤ[x]/f(x) such that a(x)b(x) = c (mod f(x)) for the smallest possible positive integer scale c. In this paper, we investigate the scaled inverse of (xi - xj) modulo cyclotomic polynomial of the form Φps (x) or Φpsqt (x), where p, q are primes with p < q and s, t are positive integers. Our main results are that the coefficient size of the scaled inverse of (xi - xj) is bounded by p - 1 with the scale p modulo Φps (x), and is bounded by q - 1 with the scale not greater than q modulo Φpsqt (x). Previously, the analogous result on cyclotomic polynomials of the form Φ2n (x) gave rise to many lattice-based cryptosystems, especially, zero-knowledge proofs. Our result provides more flexible choice of cyclotomic polynomials in such cryptosystems. Along the way of proving the theorems, we also prove several properties of {xk}k∈ℤ in ℤ[x]/Φpq(x) which might be of independent interest.

Development of ETRI satellite simulator-ARTSS

  • Kang, J.Y.;Lee, S.;Hong, K.Y.;Shin, K.K.;Rhee, S.W.;Choi, W.S.;Oh, H.S.;Kim, J.M.;Chung, S.J.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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    • pp.49-53
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    • 1994
  • Advanced Real-Time Satellite Simulator(ARTSS) has been developed to support the telemetry, tracking and command operations of the ETRI satellite control system and to provide satellite engineers a more powerful and informative satellite simulations tool on the desktop. To provide extensive simulation functions for a communication satellite system in the pre-operational and operational missions, ARTSS uses a geosynchronous orbit(GEO) satellite model consisting of the attitude and orbit control subsystem, the power subsystem, the thermal subsystem, the telemetry, command and ranging subsystem, and the communications payload subsystem. In this paper, the system features and functions are presented and the satellite subsystem models are explained in detail.

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