• 충청수학회지
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• 제24권1호
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• pp.35-43
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• 2011

In this paper we define the convergence of ${\delta}$-filters and study them. We show that ${\delta}$-filters on a Hausdorff space X converge at most one point in X. We also show that in a P-space X, ${\delta}$-filters on X converge at most one point in X if and only if X is a Hausdorff space.

• 호남수학학술지
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• 제39권2호
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• pp.199-216
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• 2017

In the paper [Y. B. Jun, B. Davvaz and A. Khan, Filters of ordered semigroups based on the fuzzy points, JIFS 24 (2013) 619-630]. Jun et al. discussed the notion of (${\in},{\in}{\vee}q_k$)-fuzzy left (resp., right) filters as a generalization of the notion of (${\in},{\in}{\vee}q$)-fuzzy left (resp., right) filters of ordered semigroups. In this article, we try to obtain a more general form that (${\in},{\in}{\vee}q_k$)-fuzzy left (resp., right) filters in ordered semigroups. The notion of (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp., right) filters is discussed, and several properties are investigated. Characterizations of an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp., right) filter are established. A condition for an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp., right) filter to be a fuzzy left (resp., right) filter is provided. The important achievement of the study with an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (right) filter is that the notion of an (${\in},{\in}{\vee}q_k$)-fuzzy left ( right) filter and hence an (${\in},{\in}{\vee}q$)-fuzzy left (resp. right) filter are special cases of an (${\in},{\in}{\vee}q_k^{\delta}$)-fuzzy left (resp. right) filter, and thus several results in published papers are becoming corollaries of our results obtained in this paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.199-203
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• 2004

In this paper, we only describe the digital block of two-channel 18-bit analog-to-digital (A/D) converter employing sigma-delta method and xl28 decimation. The device contains two fourth comb filters with 1-bit input from sigma­delta modulator. each followed by a digital half band FIR(Finite Impulse Response) filters. The external analog sigma-delta modulators are sampled at 6.144MHz and the digital words are output at 48kHz. The fourth-order comb filter has designed 3 types of ways for optimal power consumption and signal-to-noise ratio. The following 3 digital filters are designed with 12tap, 22tap and 116tap to meet the specification. These filters eliminate images of the base band audio signal that exist at multiples of the input sample rate. We also designed these filters with 8bit and 16bit filter coefficient to analysis signal-to-noise ratio and hardware complexity. It also included digital output interface block for I2S serial data protocol, test circuit and internal input vector generator. It is fabricated with 0.35um HYNIX standard CMOS cell library with 3.3V supply voltage and the chip size is 2000um by 2000um. The function and the performance have been verified using Verilog XL logic simulator and Matlab tool.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.400-402
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• 1994

This paper presents a digital implementation of delta modulation Technique for Active Power Filters. Delta modulated scheme is to control the harmonic-compensating current indirectly by adjusting the capacitor voltage to be sinusoidal. The overall control system has two feedback loops. One is the outer propotional feedback for loop regulating the dc current of active filters and the other is the inner feedback loop for maintaining the ac current waveform to be sinusoidal, and have zero power factor angle(i.e. unity power factor). The characteristics of the proposed is investigated by digital simulation using ACSL and experimental results are obtained by TMS370C756 Single-Chip Microprocessor relative to analog delta modulation technique.

• 전기학회논문지P
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• 제59권1호
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• pp.64-70
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• 2010

This paper presents how to decide on tuning factor(${\delta}$) and quality factor(Q) values in design of single-tuned passive harmonic filters. Tuning factor(${\delta}$) and quality factor(Q) values have to consider before decision on circuit parameters of passive filters. A Study on these two value has not been scarcely performed and only experienced values has been used in passive harmonic filter design by far. As a experienced value, in cases of 5th and 7th filter, tuning factor(${\delta}$) is about 0.94 and 0.96 respectively and quality factor(Q) is, in all cases of, 50. If Single-tuned passive harmonic filter will be off-tuned, performance of filter will be decreased steeply and occur to parallel resonance between system reactance and filter capacitance. Therefore During the operation, In order not to off-tuning, Filter must be tuned at former order than actual tuning order. This is the same that total impedance of filter must have a reactive impedance. In this paper, Tuning factor(${\delta}$) is decided via example of real system and using the bode-plot and then performance of filters confirmed by filter current absorbtion rate. And Quality factor(Q) decided using the bode plot in example system and then performance of filters confirmed by filter current absorbtion rate also, which makes a calculated filter parameters to satisfy IEEE-519 distortion limits. Finally, Performance of the designed passive harmonic filter using the tuning factor(${\delta}$) and quality factor(Q) values, decided in this paper is verified by experiment and shows that 5th, 7th, 9th, 11th and 13th current harmonic distortions are decreased within IEEE-519 distortion limits, respectively.

• 대한전자공학회논문지
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• 제22권3호
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• pp.16-22
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• 1985

In this paper a new algorithm named modified delta modulation (MDM) for encoding filter coefficients is proposed. And this paper presents the designing method of multiplier less FIR filters rosin영 Proposed MDM a19orithm. In the delta modulation (DM) system the quantiaation levels consist of two levels $\pm$1, but in newly proposed MDM algorithm quantization levels are extended to many levels 0, $\pm$2$^n$, n=0, 1, 2... It is recognized by the result of computer simulations that frequency response of multi-plierless FIR filters designed by MDM algorithm is relatively good. And comparing with con-ventional FIR filters on the number of hardware devices, this filter needs a little increased memory, but regardless of filter order it needs only one multiplier which is used for signal scaling.

• Journal of applied mathematics & informatics
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• 제37권5_6호
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• pp.383-397
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• 2019

In this paper, we introduce ${\delta}$-fuzzy ideals in a pseudo complemented distributive lattice in terms of fuzzy filters. It is proved that the set of all ${\delta}$-fuzzy ideals forms a complete distributive lattice. The set of equivalent conditions are given for the class of all ${\delta}$-fuzzy ideals to be a sub-lattice of the fuzzy ideals of L. Moreover, ${\delta}$-fuzzy ideals are characterized in terms of fuzzy congruences.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.861-865
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• 1991

Sigma delta modulation has been the preferred technique for oversampling conversion. In this paper we present the basic principles of oversampled sigma-delta Converters. Basic operation and theory behind sigma-delta modulation is reviewed. The different structures of the sigma-delta converters are described and the concepts of designing modulators and digital filters are discussed. The latest designs are also reviewed.

• Korean Journal of Mathematics
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• 제18권1호
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• pp.45-52
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• 2010

Generalizing $Lindel{\ddot{o}}f$ frames and almost compact frames, we introduce a concept of almost $Lindel{\ddot{o}}f$ frames. Using a concept of ${\delta}$-filters on frames, we characterize almost $Lindel{\ddot{o}}f$ frames and then have their permanence properties. We also show that almost $Lindel{\ddot{o}}f$ regular $D({\aleph}_1)$ frames are exactly $Lindel{\ddot{o}}f$ frames. Finally we construct an almost $Lindel{\ddot{o}}fication$ of a frame L via the simple extension of L associated with the set of all ${\delta}$-filters F on L with ${\bigvee}\{x^*{\mid}x{\in}F\}=e$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.736-738
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• 1993

The problems of he plentiful harmonics and low power factor have occured to the increase of semiconductor power conversion equipments. These problems should be improved by the active power filters which have been studied recently. This paper described the appliaction of delta modulation technique to current-fed filter and control performance. Through digital simulation the output characteristics of delta modulator are investigated theoretically.