• Title/Summary/Keyword: ${\omega}$-phase function

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A method of measuring frequency response function by use of characteristic M-sequence

  • Sakata, Masato;Kashiwagi, Hiroshi;Kitajima, Unpei
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10b
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    • pp.943-946
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    • 1988
  • A simple method is proposed for determining the frequency response function G(j.omega.) of a system using a pair of characteristic M-sequences (maximum length linear feed back shift register sequence). When a characteristic M-sequence is sampled with q$_{1}$ and q$_{2}$ both of which are coprime with N, where N is the period of the M-sequence, the obtained pair of sequences have conjugate complex frequency spectrum. Making use of this fact, two charcteristic M-sequences having conjugate complex frequency spectrum are applied to a system to be measured. Since the magnitude of spectrium of M-sequence is known, the gain of G(j.omega.) is directly obtained from the Fourier transform of the system output. The phase of G(j.omega.) is obtained simply by taking the average of the two phases of output spectrum.

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THE PROPERLY SUPPORTED GENERALIZED PSEUDO DIFFERENTIAL OPERATORS

  • Kang, Buhyeon
    • Journal of the Chungcheong Mathematical Society
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    • v.28 no.2
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    • pp.269-286
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    • 2015
  • In this paper, we extend the concept of the pseudo differential operators in the usual Schwartz's distribution spaces to the one of the generalized pseudo differential operators in the Beurling's generalized distribution spaces. And we shall investigate some properties of the generalized pseudo differential operators including the generalized pseudo local property. Finally, we will study the smoothness and properly supported property of these operators.

CONTINUOUS HAMILTONIAN DYNAMICS AND AREA-PRESERVING HOMEOMORPHISM GROUP OF D2

  • Oh, Yong-Geun
    • Journal of the Korean Mathematical Society
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    • v.53 no.4
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    • pp.795-834
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    • 2016
  • The main purpose of this paper is to propose a scheme of a proof of the nonsimpleness of the group $Homeo^{\Omega}$ ($D^2$, ${\partial}D^2$) of area preserving homeomorphisms of the 2-disc $D^2$. We first establish the existence of Alexander isotopy in the category of Hamiltonian homeomorphisms. This reduces the question of extendability of the well-known Calabi homomorphism Cal : $Diff^{\Omega}$ ($D^1$, ${\partial}D^2$)${\rightarrow}{\mathbb{R}}$ to a homomorphism ${\bar{Cal}}$ : Hameo($D^2$, ${\partial}D^2$)${\rightarrow}{\mathbb{R}}$ to that of the vanishing of the basic phase function $f_{\underline{F}}$, a Floer theoretic graph selector constructed in [9], that is associated to the graph of the topological Hamiltonian loop and its normalized Hamiltonian ${\underline{F}}$ on $S^2$ that is obtained via the natural embedding $D^2{\hookrightarrow}S^2$. Here Hameo($D^2$, ${\partial}D^2$) is the group of Hamiltonian homeomorphisms introduced by $M{\ddot{u}}ller$ and the author [18]. We then provide an evidence of this vanishing conjecture by proving the conjecture for the special class of weakly graphical topological Hamiltonian loops on $D^2$ via a study of the associated Hamiton-Jacobi equation.

A Study on the Characteristics of the Corrugated Feed-Horn Antenna Using FDTD Method (FDTD 방법을 이용한 Corrugated Feed-Horn Antenna 의 특성에 대한 연구)

  • 박혁균;성혁제;손병문;구연건
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.4
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    • pp.619-626
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    • 2000
  • The electromagnetic fields of the corrugated annular feed-horn antenna have been analyzed exactly by using the finite-difference time-domain (FDTD) technique. The radiation pattern and return loss characteristics of the antenna were obtained as a function of the impedance of feeding coaxial line at 11.8GHz. The return loss was determined to be less than -25dB at 30$\Omega$. It was confirmed that the phase error is less compared to that of the antenna without corrugation, but the directivity of the radiation pattern needs to be improved.

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Impedance Parameters of Electrical Double Layer I. A Determination Method of Electrolytic Cell Impedance Parameter on the Platinum Electrode (전기이중층의 임피던스 파라미터 I. 백금전극을 사용한 전해쎌 임피던스 파라미터의 결정방법)

  • Kum-Sho Hwang;Un-Sik Kim
    • Journal of the Korean Chemical Society
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    • v.30 no.3
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    • pp.273-281
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    • 1986
  • This study is focused on the correct measurement of the equations for the determination of the impedance parameters-the differential capacity of the double layer $C_d$, solution resistance $R_Q$, transfer resitance $R_i$, and adsorption pseudcapacity $C_{\phi}$/ The application of only an imaginary part of complex function of ${\omega}$ at the sinusoidal steady state indicates the following equations of total impedance: at low frequency $|Z_{LF}|=1/{\omega}_1\;C_{\phi}\;{\sqrt{1+{{\omega}_1}^2/{\omega}^2}$, at high frequency $|Z_{HF}|={\omega}_2/({\omega}_1{\omega}_3C{\phi})({\omega}^2+{{\omega}_2}^2)\;{\sqrt{{({\omega}^2+{\omega}_2{\omega}_3)}^2+{({\omega}_2{\omega}-{\omega_3{\omega})^2}}$. The values of the total impedance of cell, phase angle, and cell current that are necessary for the calculations of impedance parameters were experimentally measured from 200 to 6000Hz for the following supporting electrolytes, 0.5M $Na_2SO_4$, 1M NaCl, 19.373% sea water, 1M HCl, 1M $KNO_3$ and for $10^{-2}M$ KI and 60mM DBNA (Di-iso-Butylnitrosoamine) in these supporting electrolytes. The derived equations in this study shows that the values of impedance parameters of $C_d,\;C_{\phi},\;R_i\;and\;R_Q\;are\;15{\sim}40\;{\mu}F/cm^2,\;162{\sim}758\;{\mu}F/cm^2\;11.5{\sim}57.6\;ohm{\cdot}cm^2\;and\;0.5{\times}10^{-2}{\sim}4.1{\times}10^{-2}\;ohm{\cdot}cm^2$ respectively.

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Design of a Continuous-Time Filter Using the Modified Chebyshev Function and DDA (개선된 Chebyshev 함수와 DDA를 이용한 연속시간 필터 설계)

  • 최석우;윤창훈;김동용
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.12
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    • pp.1572-1580
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    • 1995
  • In this paper, a modified Chebyshev low-pass filter function is proposed. The modified Chebyshev filter function exhibits ripples diminishing toward .omega. = 0 in the passband. So, the modified filter function is realizable in the passive doubly-terminated ladder network for the order n even or odd, thus lending itself amenable to active RC or switched capacitor filters through the simulation techniques. Besides the passive doubly-terminated ladder realizability, lower pole-Q values of the modified function are accountable for improved phase and delay characteristics, as compared to classical function. We have designed the 6th order passive doubly-terminated network using the modified function. And then a continuous-time DDA(Differential Difference Amplifier) filter, which has no matching requirement, is realized by leap-frog simulation technique for fabrication. In the HSPICE simulation results, we confirmed that the designed continuous-time DDA filter characteristics are agreement with the passive filter.

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Ultra shallow function Formation of Low Sheet Resistance Using by Laser Annealing (레이져 어닐링을 이용한 낮은 면저항의 극히 얕은 접합 형성)

  • 정은식;배지철;이용재
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.05a
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    • pp.349-352
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    • 2001
  • In this paper, novel device structure in order to realize ultra fast and ultra small silicon devices are investigated using ultra-high vacuum chemical vapor deposition(UHVCVD) and Excimer Laser Annealing (ELA) for ultra pn junction formation. Based on these fundamental technologies for the deep sub-micron device, high speed and low power devices can be fabricated. These junction formation technologies based on damage-free process for replacing of low energy ion implantation involve solid phase diffusion and vapor phase diffusion. As a result, ultra shallow junction depths by ELA are analyzed to 10~20 nm for arsenic dosage (2$\times$10$^{14}$ $\textrm{cm}^2$), excimer laser source(λ=248nm) is KrF, and sheet resistances are measured to 1k$\Omega$/$\square$ at junction depth of 15nm.

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A Development of SFD for the measurement of rotational velocity vector (회전 속도 Vector 계측을 위한 공간필터 검출기의 개발)

  • Go, Hyun-Min;Rho, Do-Hwan
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.621-624
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    • 1999
  • In this paper, we propose the non-contact method to measure rotational speed vector using spatial filtering method. The rotational speed $\omega$ is known by the frequency of output sinusoidal signal direct proportional to that and the rotational direction is given by the phase delay from the weighting function design of spatial filter.

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Design of real time FIR filter for removal of noise in ECG (ECG 신호의 잡음 제거를 위한 실시간 FIR 필터의 설계)

  • 황선철;이경중;이명호
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.690-693
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    • 1987
  • Base-line wandering and 60Hz noise in ECG are removed by linear phase FIR filter. The important problem in FIR filtering is to reduce the number of impulse response coefficients. It can be reduced by symmetrical impulse response. The ripple is improved by window function .omega.(n). And the determination of filter accuracy is proposed by PRD(percent rms difference) algorithm.

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Possible p-wave condensed conductor (or superconductor) for La$_{1-x}Ca_xMnO_3$ films (La$_{1-x}Ca_xMnO_3$ 박막에서 p파 초전도의 가능성)

  • Kim, Hyun-Tak;Kang, Kwang-Yong
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.200-205
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    • 1999
  • In the ferromagnetic phase with electrons for La$_{1-x}$(Ca or Sr)$_x$MnO$_3$, films, a remnant resistivity of the order of 10$^{-8}$ ${\omega}$m is observed up to 100 K and increases exponentially with temperature up to T$_c$ and above one Tesla as a function of magnetic field strength (a positive magnetoresistivity). The phase below T$_c$ is regarded as a polaronic state with a polaronic tunneling conduction. Possible p-wave condensation (or superconductor) with a parabolic density of states and the phase separation are discussed on the basis of the two-fold degeneracy of ${\varrho}_{\delta}$ orbitals.

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