• Title/Summary/Keyword: z-transform

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CONDITIONAL INTEGRAL TRANSFORMS AND CONVOLUTIONS OF BOUNDED FUNCTIONS ON AN ANALOGUE OF WIENER SPACE

  • Cho, Dong Hyun
    • Journal of the Chungcheong Mathematical Society
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    • v.26 no.2
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    • pp.323-342
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    • 2013
  • Let $C[0,t]$ denote the function space of all real-valued continuous paths on $[0,t]$. Define $Xn:C[0,t]{\rightarrow}\mathbb{R}^{n+1}$ and $X_{n+1}:C[0,t]{\rightarrow}\mathbb{R}^{n+2}$ by $X_n(x)=(x(t_0),x(t_1),{\cdots},x(t_n))$ and $X_{n+1}(x)=(x(t_0),x(t_1),{\cdots},x(t_n),x(t_{n+1}))$, where $0=t_0$ < $t_1$ < ${\cdots}$ < $t_n$ < $t_{n+1}=t$. In the present paper, using simple formulas for the conditional expectations with the conditioning functions $X_n$ and $X_{n+1}$, we evaluate the $L_p(1{\leq}p{\leq}{\infty})$-analytic conditional Fourier-Feynman transforms and the conditional convolution products of the functions which have the form $${\int}_{L_2[0,t]}{{\exp}\{i(v,x)\}d{\sigma}(v)}{{\int}_{\mathbb{R}^r}}\;{\exp}\{i{\sum_{j=1}^{r}z_j(v_j,x)\}dp(z_1,{\cdots},z_r)$$ for $x{\in}C[0,t]$, where $\{v_1,{\cdots},v_r\}$ is an orthonormal subset of $L_2[0,t]$ and ${\sigma}$ and ${\rho}$ are the complex Borel measures of bounded variations on $L_2[0,t]$ and $\mathbb{R}^r$, respectively. We then investigate the inverse transforms of the function with their relationships and finally prove that the analytic conditional Fourier-Feynman transforms of the conditional convolution products for the functions, can be expressed in terms of the products of the conditional Fourier-Feynman transforms of each function.

Hwasan Wetland Vegetation in Gunwi, South Korea: with a Phytosociological Focus on Alder (Alnus japonica (Thunb.) Steud.) Forests (군위군 화산습지의 식생: 오리나무림을 중심으로)

  • Kim, Jong-Won;Lee, Seung-eun;Lee, Jung-a
    • Korean Journal of Ecology and Environment
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    • v.50 no.1
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    • pp.70-78
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    • 2017
  • The Hwasan wetland vegetation is observed at mountain basin (644~780 m a.s.l.) where had become a potential land for indigenous people since prehistoric period. We phytosociologically investigated old-growth alder (Alnus japonica) forests using the $Z\ddot{u}rich$-Montpellier School's method and analyzed their spatial distribution pattern by actual vegetation map. Species performance was determined by using coverage and r-NCD. Viburnum opulus var. calvescens-Alnus japonica community syntaxonomically belonging to the Alnetea japonicae was first described and composed of three subunits: Salix koreensis subcommunity, typical subcommunity, and Pyrus ussuriensis subcommunity. Present plant community was compared with vicariant syntaxa such as Molinia japonica-Alnus japonica community, Rhamno nipponicae-Alnetum japonicae, and Aceri-Salicetum koreensis. Hwasan's alder forest, an alluvial terrace vegetation type on valley fan in the montane zone, is evaluated as vegetation class [I], which is a sort of benchmark plant community potentially on mountain wetlands in southeastern part of the Korean Peninsula. Simultaneously we suggested an establishment of the national strategy for habitat conservation free from hydrologically radical transform due to military utilization.

THE MICROHARDNESS AND THE DEGREE OF CONVERSION OF LIGHT CURED COMPOSITE RESIN AND DUAL CURED RESIN CEMENTS UNDER PORCELAIN INLAY (도재인레이 하방에서 광중합형 복합레진과 이중중합형 복합레진시멘트의 미세경도와 중합률에 관한 연구)

  • Kim, Seung-Soo;Cho, Sung-Sik;Um, Chung-Moon
    • Restorative Dentistry and Endodontics
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    • v.25 no.1
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    • pp.17-40
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    • 2000
  • Resin cements are used for cementing indirect esthetic restorations such as resin or porcelain inlays. Because of its limitations in curing of purely light cured resin cements due to attenuation of the curing light by intervening materials, dual cured resin cements are recommended for cementing restorations. The physical properties of resin cements are greatly influenced by the extent to which a resin cures and the degree of cure is an important factor in the success of the inlay. The purpose of this study was to evaluate the influence of porcelain thickness and exposure time on the polymerization of resin cements by measuring the microhardness and the degree of conversion, to investigate the nature of the correlation between two methods mentioned above, and to determine the exposure time needed to harden resin cements through various thickness of porcelain. The degree of resin cure was evaluated by the measurements of microhardness [Vickers Hardness Number(VHN)] and degree of conversion(DC), as determined by Fourier Transform Infrared Spectroscopy(FTIR) on one light cured composite resin [Z-100(Z)] and three dual cured resin cements [Duo cement(D), 3M Resin cement(R), and Dual cement(DA)] which were cured under porcelain discs thickness of 0mm, 1mm, 2mm, 3mm with light exposure time of 40sec, 80sec, 120sec, and regression analysis was performed to determine the correlation between VHN and DC. In addition, to determine the exposure time needed to harden resin cements under various thickness of porcelain discs, the changes of the intensity of light attenuated by 1mm, 2mm, and 3mm thickness of porcelain discs were measured using the curing radiometer. The results were obtained as follows ; 1. The values of microhardness and the degree of conversion of resin cements without intervening porcelain discs were 31~109VHN and 51~63%, respectively. In the microhardness Z was the highest, followed by R, D, DA. In the degree of conversion, D and DA was significantly greater than Z and R(p<0.05). 2. The microhardness and the degree of conversion of the resin cements decreased with increasing thickness of porcelain discs, and increased with increasing exposure time, D and R showed great variation with inlay thickness and exposure time, whereas, DA showed a little variation. 3. The intensity of light through 1mm, 2mm, and 3mm porcelain inlays decreased by 0.43, 0.25, and 0.14 times compared to direct illumination, and the respective needed exposure times are 53 sec, 70 sec, and 93 sec. In D and R, 40 sec of light irradiation through 2mm porcelain disc and 80 sec of light irradiation through 3mm porcelain disc were not enough to complete curing. 4. The microhardness and the degree of conversion of the resin cements showed a positive correlationship(R=0.791~0.965) in the order of R, D, Z, DA. As the thickness of porcelain discs increased, the decreasing pattern of microhardness was different from that of the degree of conversion, however.

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Automatic Motion Generation from the Posture Template

  • Lee, Chang-Mug;Kwon, Oh-Young;Seok, Kwang-Ho;Kim, Yoon-Sang
    • Journal of information and communication convergence engineering
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    • v.8 no.2
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    • pp.191-196
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    • 2010
  • This paper presents automatic generation of robot motion using posture template in physical training system. In this system, we define a human-like generic template with two angles, then, we generate robot motion that has used angle data of the created template. The angle data is transformed automatically to the most similar motion. This is achieved by suitable expressions for robot specification. The expressions intend to differences of angle measurement on X,Y,Z planes and DOF constraint. We choose several postures and create generic templates for chosen postures. Robot motions are also generated from generic templates by expressions.

Application of Minimum Phase Condition to Acoustic Impedance Measurement (최소 위상 조건을 적용한 음향 임피던스 측정)

  • Lim, Byoung-Duk;Heo, Jun-Hyeok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.855-860
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    • 2005
  • For the accurate measurement of acoustic properties of a surface, efforts have been made to reduce errors caused by external disturbance. If the reflection coefficient is considered as a transfer function between reflected wave and incident wave, causality is required between them and the reflection coefficient should be of minimum phase. In this thesis, the minimum phase condition is applied to measure correct reflection coefficient. The reflection coefficient is approximated as a rational function in the Z domain by minimizing the sum square error. Then the minimum phase reflection coefficient is reconstructed using the distribution of poles and zeros of the reflection coefficient model. The incident wave, the reflected wave and the impulse response function of causality are recalculated from the minimum phase reflection coefficient for further applications.

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Novel Flow Suppression Technique in MRI (핵자기 공명 영상에서 새로운 유속 흐름제거 방법)

  • Ro, Y.M.;Cho, Z.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1992 no.05
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    • pp.92-97
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    • 1992
  • The pulsatile nature of blood flow makes artefacts in 2D Fourier transform image. Spatial presaturation is known to be effective in eliminating flow artefacts when the spin echo acquisition is employed. However. this method requires additional RF pulse and spoiling gradient for presaturation. In this paper a new flow saturation technique which does not require additional saturation-RF and gradient is proposed. The proposed technique is equivalent to the existing saturation technique but the elimination of the flow component is achieved by a pair of tailored $90^{\circ}-180^{\circ}$ RF pulses in tile spin echo sequence. By use of two tailored RF pulses with opposite phase polarity, a linear phase gradient is generated for those moving materials and consequently all the spins of moving materials become dephased thereby no signal is observable. Computer simulations and experimental results obtained using both a phantom and a human volunteer with a 2.0 T whole body system are also presented.

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The Effect of Group Mean Differences upon Factor Analysis (상관행렬의 구조분석에서 집단평균차이의 효과: 요인분석기법을 중심으로)

  • 김청택;이소영
    • Proceedings of the Korean Association for Survey Research Conference
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    • 2001.04a
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    • pp.109.2-130
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    • 2001
  • The purpose of this study is (1) to demonstrate that ignoring group differences may mislead to incorrect conclusion when analyzing correlation data (e.g., factor analysis), (2) to highlight the importance of the data analytic method considering group differences, and (3) to provide ways of incorporating group differences in data analysis. In study, 1, ignoring group difference in factor analysis may mislead to incorrect factor structure. To remedy this, z-transform method and group analysis tool in covariance structure models were suggested. In study 2, the group differences effect was illustrated by using real data (IQ test data).

The Effect of Group Mean Differences upon Factor Analysis (상관행렬의 구조분석에서 집단평균차이의 효과: 요인분석기법을 중심으로)

  • 김청택;이소영
    • Survey Research
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    • v.2 no.2
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    • pp.109-130
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    • 2001
  • The purpose of this study is (1) to demonstrate that ignoring group differences may mislead to incorrect conclusion when analyzing correlation data (e.g.. factor analysis). (2) to highlight the importance of the data analytic method considering group differences. and (3) to provide ways of incorporating group differences in data analysis. In study 1. ignoring group difference in factor analysis may mislead to incorrect factor structure. To remedy this. z-transform method and group analysis tool in covariance structure models were suggested. In study 2. the group differences effect was illustrated by using real data (IQ test data).

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The Speed Control of a Marine Diesel Engine with Electro Hydraulic Governor by using W Transformation Method (w 변환법에 의한 전기 - 유압식 조속기를 가진 박용디젤기관의 속도제어)

  • 강창남;박진길
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.2
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    • pp.195-205
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    • 1997
  • The propulsion marine diesel engine have been widely applied with a mechanical- hydraulic governor to control the ship speed for long time. But it was recently very difficult for the mechani¬cal - hydraulic governor to control the speed of engine under the condition of low speed and low load because of jiggling by rough fluctuation of rotating torque and hunting by dead time of Desiel engnie The performance improvement of mechanical - hydraulic governor is required to solve these problems of control system. The electro - hydraulic governor using PID algorithm is provided to compensate the faults of mechanical- hydraulic governor. In this paper, in order to analyze the ship speed control system, the transfer function was converted from the z tansformation to w transformation. The influence of dead time changing by engine speed which induces hunting phenomena was investigated by Nichols chart of w plane. As a method of performance improvement of mechanical hydraulic governor, a Eletro - hydraulic governor shows that fine control results can be obtained through optimal parameter tuning of PID

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A Study on the Signal Status Analysis Using the Maintenance System of the TDX Signaling Equipment (TDX 신호장치 유지보수 시스템을 이용한 신호상태분석에 관한 연구)

  • 윤대환;임채탁
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.5
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    • pp.73-81
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    • 1993
  • We have developed a system which can analyze the status of signal sent from/received to a signalling service equipment within the fully electronic switching system such as TDX-10. The system has such functions that acquire PCM signal of the preferred channel from the subhighway of the thirth-two channel by which a Universal Signal Tr ansceiver Unit(USTU) is connected with Time Switch Unit (TSU), and then classify the type of signal such as R2MFC/DTMF/CCT/VOICE, and determine the digit. Up to now, we have analyzed the frequency spec trum using the FFT. This paper describes the developement of PCM acquirer which can analyze the signal characteristics by acquiring the PCM signal in SHW(subhighway), and proposes the CZT(Chirp Z-Transform) algorithm. An algorithm which analyzes the acquired signal and determines the signal frequency and the corresponding power spectrum using the CZT is also discussed here.

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