• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.923-924
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• 2012

원자력발전은 기본적으로 공급의 안정성과 경제성을 갖추고 있는 에너지원으로서 전력생산에 관한 자원 및 환경문제의 한계를 극복한 에너지원으로 평가받고 있다. 그러나 최근 일본 후쿠시마 원전사고로 독일과 이탈리아 등은 원전의 단계적인 철폐와 도입을 취소하는 등 원전의 안정성에 대한 논의가 활발히 이루어지고 있다. 우리나라도 최근 원전부품 납품에 관한 비리가 발생하는 등 원전에 관한 크고 작은 안전사고가 발생하고 있다. 따라서 본 논문에서는 원전부품을 효율적이고 안전하게 관리하기 위해 RFID를 활용한 원전부품의 공급사슬관리시스템의 구축 방안을 제안한다.

• 한국통신학회논문지
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• 제16권5호
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• pp.413-423
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• 1991

3RC, 3SRC, 4SRC, TFM등과 같은 몇몇 디지틀 PRCPM 신호는 정 진폭 특성과 밀집된(Compact) 전력 스펙트럼을 갖는다. 그러나 페이딩하에서 단순한 주파수 검파를 사용했을 때 이들의 BER은 너무 높다. 이는 근접 비트들 때문에 생기는 높은 ISI에 기인한다. 본 논문에서는 하나의 근접 비트 때문에 생기는 ISI 재기를 위해 DFE(Decision Feedback Equalization)을 사용하였고, 이때의 BER 성능 향상을 이론적으로 살펴보았다. 또한, DEF를 사용한 경우와 사용하지 않은 경우의 BER 성능 비교를 위해 수치 결과들을 제시하였다.

• 한국IT서비스학회지
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• 제15권1호
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• pp.167-178
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• 2016

Spectrum sensing in cognitive radio (CR) has a great role in order to utilize idle spectrum opportunistically, since it is responsible for making available dynamic spectrum access efficiently. In this research area, collaboration among multiple cognitive radio users has been proposed for the betterment of detection reliability. Even though cooperation among them improves the spectrum sensing performance, some falsely reporting malicious users may degrade the performance rigorously. In this article, we have studied the detection and nullifying the harmful effects of such malicious users by applying some well known outlier detection methods based on Grubb's test, Boxplot method and Dixon's test in cooperative spectrum sensing. Initially, the performance of each technique is compared and found that Boxplot method outperforms both Grubb's and Dixon's test for the case where multiple malicious users are present. Secondly, a new algorithm based on reputation and weight is developed to identify malicious users and cancel out their negative impact in final decision making. Simulation results demonstrate that the proposed scheme effectively identifies the malicious users and suppress their harmful effects at the fusion center to decide whether the spectrum is idle.

• Journal of Power Electronics
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• 제17권5호
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• pp.1223-1230
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• 2017

The back emf harmonics of a permanent magnet (PM) synchronous motor is a major source of torque ripple. For torque control applications including column fitted MDPS (motor driven power steering) systems, it is essential to reduce the mechanical vibrations due to torque ripples at low speeds. In this paper, a torque ripple reduction algorithm for interior PM synchronous motors is proposed. The harmonic currents that cancel the $6^{th}$ order torque harmonic are added to the nominal dq currents for MTPA (maximum torque per ampere) operation. The compensated harmonic currents are derived from flux linkage harmonics based on a FFT analysis of the back emf harmonics. Simulation and experimental results verify that the $6^{th}$ order torque harmonic and THD of the torque ripple are reduced by compensating the dq harmonic currents.

• 한국지능시스템학회논문지
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• 제11권2호
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• pp.178-183
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• 2001

Welding is essential for the manufacture of a range of engineering components which may vary from very large structures such as ships and bridges to very complex structures such as aircraft engines, or miniature components for microelectronic applications. Especially, a domestic situation of the welding automation is still depend on the arc sensing system in comparison to the vision sensing system. Specially, the gap-detecting of workpiece using conventional arc sensor is proposed in this study. As a same principle, a welding current varies with the size of a welding gap. This study introduce to the fuzzy membership filter to cancel a high frequency noise of welding current, and ART2 which has the competitive learning network classifies the signal patterns the filtered welding signal. A welding current possesses a specific pattern according to the existence or the size of a welding gap. These specific patterns result in different classification in comparison with an occasion for no welding gap. The patterns in each case of 1mm, 2mm, 3mm and no welding gap are identified by the artificial neural network.

• 한국생산제조학회지
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• 제21권6호
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• pp.878-884
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• 2012

In this paper, we consider the sway suppression control problem for container cranes with the frictions between the trolley and the rail. If the friction effects in the system can be modelled, there is an improved potential to design controllers that can cancel the effects. The proposed control improves the trolley positioning and sway suppressing against various frictions. The proposed synthesis combines a variable structure control and the adaptive control to cope with various frictions including the unknown constants. First, the variable structure control with the simple switching action is designed, which is based on a class of feedback lineariztion methods for the fast stabilization of the under-actuated sway dynamics of container. Second, the adaptive control with a parameter estimation is designed, which is based on Lyapunov stability methods for suppressing the oscillation of the trolley travelling, especially due to Coulomb friction in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown under initial sway, external wind disturbances, and various frictions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1212-1217
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• 2006

This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

• 한국정보통신학회논문지
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• 제16권11호
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• pp.2388-2396
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• 2012

본 논문에서는 스테레오 음향반향제거기의 수렴특성을 향상시키기 위한 간략화된 직교투사법을 제안한다. 간단하고 안정되어 널리 사용되고 있는 기존의 NLMS 알고리즘과 비교하여, 이 기술은 음성신호와 같이 상호상관도가 높은 신호에 대해 수렴성능이 향상되고 연산량이 감소한다. 본 연구에서 제안한 SOP 알고리즘의 성능을 검증하기 위하여 모의실험용 프로그램을 작성하고 시뮬레이션을 수행하였다. 입력신호의 종류와 적응 알고리즘에 따라서 반향제거기의 수렴특성을 관찰한 결과, 제안한 알고리즘을 적용한 스테레오 반향제거기는 백색 잡음을 입력으로 사용하는 경우 약 3dB 정도, 유색 음성신호를 입력으로 사용하는 경우 약 5dB 이상의 ERLE 성능이 개선되는 것을 보여 주었다.

• 한국자동차공학회논문집
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• 제21권5호
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• pp.40-46
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• 2013

Automatic swing door for an automotive application is considered. The equation of motion for a driver side swing door is introduced and gravity cancellation control scheme is adapted. The control scheme supposed to cancel the moment due to the tilt of the car. A speed control is suggested for door operation automation but the output of the speed control is not suppose to be precise as for the manufacturing system control. In the frame of the velocity control of the door, feedback linearization was applied for collision detection. The collision detection performance is satisfactory. The estimate of the magnitude of disturbance due to the collision is close to the actual magnitude of disturbance. Simulation study has been performed to gain insight into the system behavior. Also real test on the prototype hardware has been performed for verification purpose.

• 한국통신학회논문지
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• 제28권8C호
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• pp.771-778
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• 2003

인접 기지국의 송신 신호는 단말기에서 볼 때 간섭 신호로 작용한다. 이러한 간섭 신호로 인하여 순방향 링크 용량이 줄어든다. 인접 기지국의 파일럿 간섭 신호를 제거함으로써 BER 성능을 개선할 수 있으며 순방향 링크 용량을 개선할 수 있다. 본 논문에서는 순방향 링크 용량을 개선할 수 있도록 인접 기지국에서 송신하는 파일럿 간섭 신호를 제거할 수 있는 복조기 구조를 제안하였다. 모의 실험 결과 인접 기지국의 파일럿 간섭 신호를 제거할 때 BER = 10-2를 얻기 위한 Eb/No 값이 간섭신호를 제거하지 않을 때에 비하여 3㏈ 감소하였다.