• 제목/요약/키워드: Dirac

검색결과 137건 처리시간 0.023초

비-가우시안 잡음하의 통신을 위한 바이어스된 오차 분포의 유클리드 거리 (Euclidean Distance of Biased Error Probability for Communication in Non-Gaussian Noise)

  • 김남용
    • 한국산학기술학회논문지
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    • 제14권3호
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    • pp.1416-1421
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    • 2013
  • 비-가우시안 잡음 환경의 적응 시스템을 위해, 평행 이동한 오차 분포와 오차 0에 위치한 델타 함수 사이의 유클리드 거리를 새로운 성능기준으로 제안하였다. 또한, 이 성능 기준에 근거하여 적응 알고리듬을 개발하였고, 얕은 바다에서 구한 수중 통신 다경로 채널에 충격성 잡음과 직류 바이어스 잡음이 더해진 환경으로 등화 성능을 시뮬레이션한 결과, 제안한 알고리듬이 기존의 MEDE 알고리듬 보다 5 dB 이상 향상된 MSE 성능을 보이며 오차 분포의 중심 위치가 정확히 0에 위치하였다.

위상절연체 소재 및 소자 기술 개발 동향 (Research Trend of Topological Insulator Materials and Devices)

  • 이우정;황태하;조대형;정용덕
    • 전자통신동향분석
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    • 제38권1호
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    • pp.17-25
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    • 2023
  • Topological insulators (TIs) emerge as one of the most fascinating and amazing material in physics and electronics. TIs intrinsically possess both gapless conducting surface and insulating internal properties, instead of being only one property such as conducting, semiconducting, and insulating. The conducting surface state of TIs is the consequence of band inversion induced by strong spin-orbit coupling. Combined with broken inversion symmetry, the surface electronic band structure consists of spin helical Dirac cone, which allows spin of carriers governed by the direction of its momentum, and prohibits backscattering of the carriers. It is called by topological surface states (TSS). In this paper, we investigated the TIs materials and their unique properties and denoted the fabrication method of TIs such as deposition and exfoliation techniques. Since it is hard to observe the TSS, we introduced several specialized analysis tools such as angle-resolved photoemission spectroscopy, spin-momentum locking, and weak antilocalization. Finally, we reviewed the various fields to utilize the unique properties of TIs and summarized research trends of their applications.

Influence of impulsive line source and non-homogeneity on the propagation of SH-wave in an isotropic medium

  • Kakar, Rajneesh
    • Interaction and multiscale mechanics
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    • 제6권3호
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    • pp.287-300
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    • 2013
  • In this paper, the effect of impulsive line on the propagation of shear waves in non-homogeneous elastic layer is investigated. The rigidity and density in the intermediate layer is assumed to vary quadratic as functions of depth. The dispersion equation is obtained by using the Fourier transform and Green's function technique. The study ends with the mathematical calculations for transmitted wave in the layer. These equations are in complete agreement with the classical results when the non-homogeneity parameters are neglected. Various curves are plotted to show the effects of non-homogeneities on shear waves in the intermediate layer.

레이저 다이오드의 전기적 미분특성에 관한 연구 (Electrical Derivative Characteristics of Lsaer Diodes)

  • 김창균;도만희;김상배
    • 전자공학회논문지A
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    • 제30A권7호
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    • pp.38-46
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    • 1993
  • Based on the close correlation between the optoelectronic and electrical characteristics of laser diodes, this paper is to present an exact model for electrical characteristics of laser diodes with bulk active layers so that the optoelectronic characteristics may be estimated from the electrical Characteristics. Among the considered models, the most exact model is shown to be one which uses the Fermi-Dirac integral and the bimolecular recombination and takes into account the energy-gap shrinkage with the injected carrier density.

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ASYMPTOTIC BEHAVIOR OF SINGULAR SOLUTIONS OF SEMILINEAR PARABOLIC EQUATIONS

  • BAN, HYUN JU;KWAK, MINKYU
    • 호남수학학술지
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    • 제17권1호
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    • pp.107-118
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    • 1995
  • We study the asymptotic behavior of nonnegative singular solutions of semilinear parabolic equations of the type $$u_t={\Delta}u-(u^q)_y-u^p$$ defined in the whole space $x=(x,y){\in}R^{N-1}{\times}R$ for t>0, with initial data a Dirac mass, ${\delta}(x)$. The exponents q, p satisfy $$1 where $q^*=max\{q,(N+1)/N\}$.

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집중 질량을 가진 회전하는 외팔 평판의 진동 해석 (Vibration Analysis of Rotating Cantilever Plates with a Concentrated Mass)

  • 양정식;유홍희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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    • pp.181-186
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    • 1998
  • A modelling method for the vibration analysis of rotating cantilever plates with a concentrated mass is presented. The equations of motion for the rotating plates with a concentrated mass located in an arbitrary position are derived. For the modelling of the concentrated mass, a mass density Dirac delta function is used. The effects of concentrated mass and its location, angular speed, and hub radius of the rotating plate on the natural frequencies are studied. Particularly, mode shape variations due to some parameter variations are investigated.

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THE ARCSINE LAW IN THE GENERALIZED ANALOGUE OF WIENER SPACE

  • Ryu, Kun Sik
    • 충청수학회지
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    • 제30권1호
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    • pp.67-76
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    • 2017
  • In this note, we prove the theorems in the generalized analogue of Wiener space corresponding to the second and the third arcsine laws in either concrete or analogue of Wiener space [1, 2, 7] and we show that our results are exactly same to either the concrete or the analogue of Wiener case when the initial condition gives either the Dirac measure at the origin or the probability Borel measure.

CLIFFORD $L^2$-COHOMOLOGY ON THE COMPLETE $K\"{A}$HLER MANIFOLDS

  • Pak, Jin-Suk;Jung, Seoung-Dal
    • 대한수학회지
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    • 제34권1호
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    • pp.167-179
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    • 1997
  • In the study of a manifold M, the exterior algebra $\Lambda^* M$ plays an important role. In fact, the de Rham cohomology theory gives many informations of a manifold. Another important object in the study of a manifold is its Clifford algebra (Cl(M), generated by the tangent space.

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