• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
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• pp.296-299
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• 2003

This paper shows a novel and simple IIR/FIR QMF(quadrature mirror filter) filter banks, mixed IIR and FIR structure. Here, FIR filters used for phase compensation. In this paper, we introduced analysis and synthesis filter banks, which used FIR linear phase filters and all pass filters. In result, phase response of analysis and synthesis filter banks become approximately linear characteristic. Simultaneously, a liasing distortion can be completely canceled.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.143-146
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• 1989

Narrowband bandpass waveguide filters using inducive post obstacles are designed and constructed to have an equal-ripple bandwidth of 50MHz at a center frequency of 9GHz. Both the triple-post and the single-post configurations are realized and compared. The measured results for both filters show good agreement with the theoretical calculations. When the two filters are compared, the performance of the triple-post filter is better than that of the single-post filter.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제25권4호
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• pp.267-278
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• 2018

In this paper, we introduce the notion of the (L, ${\ast}$)-filter spaces on ecl-premonoids. Moreover, we obtain various (L, ${\ast}$)-filters incuced by two (L, ${\ast}$)-filters and give their examples.

• 충청수학회지
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• 제32권1호
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• pp.53-67
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• 2019

The notions of closed elements and dense elements are introduced in BE-algebras. Characterization theorems of closed elements and closed filters are obtained. The notion of dense elements is introduced in BE-algebras. Dense BE-algebras are characterized with the help of maximal filters and congruences. The concept of D-filters is introduced in BE-algebras. A set of equivalent conditions is derived for every D-filter to become a closed filter.

• Journal of applied mathematics & informatics
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• 제37권3_4호
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• pp.235-244
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• 2019

In this paper, we introduce the notion of the (L,${\ast}$,${\odot}$)-limit spaces and investigate the relations (L,${\ast}$,${\odot}$)-limit spaces and (L,${\ast}$)-filters on ecl-premonoid. We give their examples.

• 대한전자공학회논문지
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• 제23권4호
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• pp.571-577
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• 1986

In this paper, we have investigated pole-zero shifting due to variable stopband frequency Ws and passband ripple Ap of elliptic function filters. Also we have studied the phase, group-delay, unit step response and impulse response of elliptic filters. We show that in the passband the phase linearity improves as Ws increases, and eventually it approaches that of a chebyshev function filter.

• The Journal of the Acoustical Society of Korea
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• 제17권2E호
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• pp.3-9
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• 1998

Since the introduction of hands-free phone set and teleconferencing system, acoustic echo cancellation has been a challenge for engineers. Recently many researches have shown that the best solution for the acoustic echo compensation problem is represented by an adaptive filter which iteratively tries to identify the unknown impulse response of the system from loudspeaker to microphone. In this paper, we apply the delayless subband adaptive filters and fast affine projection algorithm for the identification of room impulse response. Simulation results show 3∼8 dB more enhanced performance than conventional fullband adaptive filters or subband adaptive filters. In addition, fast affine projection algorithm shows better convergence speed at the expense of the low computational complexity than conventional LMS algorithm.

• ETRI Journal
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• 제42권1호
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• pp.26-35
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• 2020

Herein, we consider uplink multiuser massive multiple-input multiple-output systems when multiple users transmit information symbols to a base station (BS) by applying simple space-time block coding (STBC). At the BS receiver, two detection filters for each user are used to detect the STBC information symbols. One of these filters is for odd-indexed symbols and the other for even-indexed symbols. Using constrained output variance metric minimization, we first derive a special relation between the closed-form optimal solutions for the two detection filters. Then, using the derived special relation, we propose a new blind adaptive algorithm for implementing the minimum output variance-based optimal filters. In the proposed adaptive algorithm, filter weight vectors are updated only in the region satisfying the special relation. Through a theoretical analysis of the convergence speed and a computer simulation, we demonstrate that the proposed scheme exhibits faster convergence speed and lower steady-state bit error rate than the conventional scheme.

• Korean Journal of Mathematics
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• 제27권4호
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• pp.1077-1108
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• 2019

The notions of intuitionistic fuzzy UP-subalgebras and intuitionistic fuzzy UP-ideals of UP-algebras were introduced by Kesorn et al. [13]. In this paper, we introduce the notions of intuitionistic fuzzy near UP-filters, intuitionistic fuzzy UP-filters, and intuitionistic fuzzy strong UP-ideals of UP-algebras, prove their generalizations, and investigate their basic properties. Furthermore, we discuss the relations between intuitionistic fuzzy near UP-filters (resp., intuitionistic fuzzy UP-filters, intuitionistic fuzzy strong UP-ideals) and their upper t-(strong) level subsets and lower t-(strong) level subsets in UP-algebras.

• 전력전자학회논문지
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• 제21권5호
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• pp.404-410
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• 2016

To avoid the stability issues of LLCL filters, passive or active damping methods to eliminate the resonance phenomena are required. In this paper, system stability of a current control is analyzed when the active damping scheme based on the virtual resister is utilized in single-phase grid converter systems with LLCL input filters. The control performance according to the parameters of the virtual resistance is investigated. The validity of stability analysis was verified by simulation and experimental results.