• Journal of Korean Society of Disaster and Security
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• v.16 no.3
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• pp.45-56
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• 2023

In this study, the application of ANC (Active Noise Control) technology to address inter-floor noise was explored. To achieve this, an ANC system was developed to manage the heavy impact sound within the frequency range of 40 to 500 Hz. The ANC system utilized an adaptive filter employing a feedforward approach based on the Fx-LMS algorithm. To set up the ANC system, a comprehensive analysis of various variables within the system was performed using computational simulations. This process enabled the identification of optimal filter settings and system configuration arrangements. In addition, the ANC system was implemented in the inter-floor noise test room at the Korea Conformity Laboratories (KCL). Through a certified standard testing procedure, it was confirmed that the ANC system led to a 4 dB reduction in inter-floor noise when the system was activated compared to when it was turned off. The results of this study indicate that the developed ANC system has an effect significant enough to elevate the rating criteria by one level for heavy impact sound.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.385-390
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• 2009

This paper presents a novel active noise control (ANC) system using least mean square (LMS) algorithm and neural network approach for decreasing acoustic noise signals inside high-speed trains. We construct a LMS framework as a nominal ANC system and additionally design an artificial single-layered perceptron model as an auxiliary ANC which is aimed to reduce real-time residuary noise due to its nonstationary and uncertain nature. Parameter vector of the hybrid ANC is determined through online estimation to realize an adaptive ANC configuration by means of the steepest descent algorithm. We achieve simulation experiment to demonstrate the proposed ANC system employing realistic acoustic noise signals measured in Korea Train eXpress (KTX).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.1001-1004
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• 2010

Acoustic feedback and background noise variation can degrade the performance of an active noise control (ANC) system. In this paper, nonlinear ANC using a non-parametric VSS-NLMS (or NPVSS-NLMS) algorithm and online feedback path modeling is proposed, whereby the conventional linear ANC with online acoustic feedback-path modeling is further extended to nonlinear Volterra ANC with a linear acoustic feedback path. In particular, the step-size of the NPVSS-NLMS algorithm is controlled to reduce the effect of background noise variation in the ANC system. Simulation results demonstrate that the proposed approach yields better nonlinear ANC performance compared with the conventional nonlinear ANC method.

• Korean Journal of Clinical Pharmacy
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• v.25 no.3
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• pp.151-158
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• 2015

Objective: This study was designed to compare pegfilgrastim and filgrastim in diffuse large B-cell lymphoma (DLBCL) patients treated with a rituximab with cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone (R-CHOP) regimen in terms of clinical efficacy and cost-effectiveness. Method: Clinical efficacy was measured by trough level of absolute neutrophil count (ANC), days of ANC under 50% of baseline value, days of ANC under 90% of baseline value, duration of ANC recovery to baseline value, days of ANC less than $0.5{\times}10^9cells/L$, and difference of peak and trough level of ANC during 1 cycle of R-CHOP regimen. To evaluate cost-effectiveness, total prices of used filgrastim and pegfilgrastim within 1 cycle of R-CHOP were analyzed. Results: In terms of clinical efficacy, trough level of ANC and days to ANC recovery showed statistical significance. The median trough levels of ANC with administration of filgrastim and pegfilgrastim were 0.18 and 1.94 (p = 0.021), respectively, and the median durations of ANC recovery to baseline value were 5.5 days and 2 days (p = 0.023), respectively. For the median days of ANC under 50% of baseline value, days of ANC under 90% of baseline value, days of ANC less than $0.5{\times}10^9cells/L$, and difference of peak and trough level of ANC during 1 cycle of R-CHOP, the pegfilgrastim group performed better than the filgrastim group. However the difference was not statistically significant. In terms of overall expense during 1 cycle of R-CHOP, pegfilgrastim is about 3.43 times more expensive than filgrastim. Conclusion: Pegfilgrastim is more efficient than filgrastim in terms of clinical efficacy. In terms of prices, pegfilgrastim is more expensive than filgrastim for patients, but it is more convenient in clinical use. Therefore, pegfilgrastim should be the preferred choice of G-CSF for neutropenic patients. Further comparative study of pegfilgrastim and filgrastim is needed.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.260-265
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• 2014

Recently, many active noise control (ANC) systems, which employ the adaptive filter controlling method, have been reported for eliminating unwanted noise. ANC systems based on the filtered-X least mean square (FXLMS) algorithm have a problem with compensating the acoustic feedback of secondary route. It is difficult to apply the real time, because transfer function of secondary route must be measured by off-line method to solve this problem. In this paper, we propose the ANC system that applies a correlation LMS(CLMS) algorithm for improving a problem of transfer function measurement. The proposed algorithm is based on input of road noise. The proposed ANC systems have an advantage of real-time process without degradation of performance, although there are many calculation compared with FXLMS algorithm.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1456-1467
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• 1990

The time domain adaptive noise canceller (time domain ANC) with the adaptive compensator and its algorithm, so called compensated least mean squares(CLMS) algorithm, had been introduced to improve the performance of ANC[1]. In this paper the time domain ANC with the adaptive compensator is transformed into the frequency domain ANC with the adaptive ocmpensator. An compensated frequency-domain least mean squares(CFLMS) algorithm that can adapt the proposed frequency domain ANC is presented.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.461-469
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• 2019

In the present work, we present a new effective hydrophilicity modifier for polysulfone (PSf) membrane. Firstly, amphiphilic nanocellulose (ANC) with different substitution degrees (SD) was synthesized by esterification reaction with nanocellulose (NC) and dodecyl succinic anhydride (DDSA). The SD and morphology of ANC were characterized by titration method and transmission electron microscopy (TEM). Then, the polysulfone (PSf)/ANC blend membranes were prepared via an immersion phase inversion method. The influence of SD on the morphology, structure and performances of PSf/ANC blend membrane were carefully investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), mechanical property test, contact angle measuring instrument and filtration experiment. The results showed that the mechanical property, hydrophilicity and anti-fouling property of all the PSf/ANC blend membranes were higher than those of pure PSf membrane and PSf/NC membrane, and the membrane properties were increased with the increasing of SD values. As ANC-4 has the highest SD value, PSf/ANC-4 membrane exhibited the optimal membrane properties. In conclusion, the prepared ANC can be used as an additive to improve the hydrophilicity and anti-fouling properties of polysulfone (PSf) membrane.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.565-567
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• 2004

In active noise control (ANC) systems, the convergence behavior of the conventional Filtered-X Least Mean Square (FXLMS) algorithm may be affected by nonlinear distortions in the secondary path (e.g., in the power amplifiers, loudspeakers, transducers, etc.), which may lead to degradation of the error-reduction performance of the ANC systems. In this paper, a stable FXLMS algorithm with fast convergence is proposed to compensate for undesirable nonlinear distortions in the secondary-path of ANC systems by employing the Volterra filtering approach. In particular, the proposed approach is based on the utilization of the conventional P-th order inverse approach to nonlinearity compensation in the secondary path of ANC systems. Finally, the simulation results showed that the proposed approach yields a better convergence behavior In the nonlinear ANC systems than the conventional FXLMS.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.257-259
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• 2012

친환경 시대로 나아가는 현재, 능동소음제어는 저주파소음을 줄이기 위한 좋은 방법이다. 또한 수동소음제어만으로 선박소음을 제어하기에는 물리적인 무게가 심각히 가중되어 한계를 가지게 된다. ANC 시스템은 이러한 문제를 해결해 줌과 더불어 다양하게 변화하는 환경소음까지 줄여주는 특성을 가지고 있다. 우리는 본 논문에서 선박의 환경소음을 줄이기 위하여 LMS 알고리즘과 신경회로망 알고리즘을 기반으로하는 ANC 시스템을 제안한다. 먼저 선박과 유사한 유도전동기의 소음을 측정하고 다음으로 ANC 시스템을 위한 LMS 구조를 구축한다. 그리고 소음의 비정치와 불확실성 때문에 단층 퍼셉트론 모델로 디자인된 신경회로망 알고리즘을 추가하여 실시간으로 소음을 줄이도록 하였다. 이 하이브리드 ANC 시스템은 최급강하기법의 방법으로 파라미터 값들이 온라인으로 실시간 추정되며, 제안된 ANC 시스템은 컴퓨터 시뮬레이션을 이용하여 그 성능을 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.949-952
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• 2020

층간 소음으로 인한 갈등, 직장에서 발생하는 소음으로 인한 청력 감소 등 소음으로 인한 많은 문제들이 최근 들어 많이 대두되고 있다. 소음을 없애기 위해서는 물리적인 방법도 있지만 ANC 기술을 이용하여 소음을 없애는 방법도 있다. ANC 란 기존 소음과 반대 위상인 파장을 출력해 상쇄간섭을 일으켜 소음을 줄여주는 기술이다. AI_ANC 기술은 기존에 ANC 기술의 한계점(Feedback, Time Gap)을 극복하기 위해 Feed forward 방식과 AI 를 접목시켜 능동적으로 소음을 감소시킨다. 이기술은 층간 소음, 공장 소음 더 나아가 다양한 이동수단까지 범용적으로 활용성이 뛰어나다.