• Journal of Communications and Networks
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• 제18권1호
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• pp.27-39
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• 2016

This paper derives and analyzes a novel block fast Fourier transform (FFT) based joint detection algorithm. The paper compares the performance and complexity of the novel block-FFT based joint detector to that of the Cholesky based joint detector and single user detection algorithms. The novel algorithm can operate at chip rate sampling, as well as higher sampling rates. For the performance/complexity analysis, the time division duplex (TDD) mode of a wideband code division multiplex access (WCDMA) is considered. The results indicate that the performance of the fast FFT based joint detector is comparable to that of the Cholesky based joint detector, and much superior to that of single user detection algorithms. On the other hand, the complexity of the fast FFT based joint detector is significantly lower than that of the Cholesky based joint detector and less than that of the single user detection algorithms. For the Cholesky based joint detector, the approximate Cholesky decomposition is applied. Moreover, the novel method can also be applied to any generic multiple-input-multiple-output (MIMO) system.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.233-236
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• 2003

원격 모니터링 시스템 위한 실장형 리눅스 지능형 제어기를 구현한다. 실장형 리눅스 지능형 제어기의 하드 코어는 32비트 cpu로서 구성되었고 실시간 모니터링과 FFT을 수행 할 수 있도록 설계되었다. 그리고 모니터링 시스템은 자바에 의한 인터넷과 GUI 환경에서 수행되도록 설계되었다. 상세설계와 기능적 해석을 시스템 기반에서 수행되었다.

• 한국정보통신학회논문지
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• 제7권3호
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• pp.526-531
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• 2003

교량 진단을 위한 새로운 Linux 실장 지능형 제어기 및 원격 모니터링 시스템을 구현한다. Linux 실장 지능형 제어기의 하드 코어는 32비트 CPU로서 구성되었고 교량 진단을 위해 실시간 모니터링과 FFT를 수행 할 수 있도록 설계되었다. 그리고 모니터링 시스템은 Java에 의한 인터넷 환경 및 GUI 환경에서 수행되도록 설계되었다. 상세 설계와 기능적 해석을 시스템 기반에서 수행되었다.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1256-1261
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• 2009

Today, implementation of the defect detection in laser welding has been researched for a long time, but most studies have been made around thin plate within $1{\sim}3mm^t$. Therefore, this study was measured and analyzed light emission signals of the induced plasma in $CO_2$ laser lap welding of $6mm^t$ Zn primer-coated steel, and based on this analysis, research made an investigation into possibility of monitoring in thick plate welding. It was been analyzing the measured signals by RMS and FFT processing, as a results, we were able to confirm definite difference of two signals between humping bead and sound bead. Thus, possibility of real time monitoring in $CO_2$ laser lap welding verified experimentally.

• 대한전자공학회논문지TC
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• 제38권9호
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• pp.21-28
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• 2001

DTMF(multi-tone multi-frequency) 신호의 경제적인 검출은 저렴한 가격의 통신장비를 개발하는데 중요한 요소이다. 현재 사용하고 있는 전전자식 교환기의 각 채널은 서로 독립된 DTMF수신기 회로를 갖고 있으며, 검출된 시노를 프로세서에 알려준다. 이때 수신기는 신호검출을 위해 DFT, FFT 및 Goertzel과 같은 알고리듬을 사용한다. 본 논문은 다중채널 DTMF 수신기 신호분석에 QFT(quick Fourier transform) 알고리듬을 적용한다. 연산수 비교를 통해 기존의 FFT, Goertzel 및 DFT 알고리듬보다 메모리 소모를 줄일 수 있고, 실시간 처리 능력이 향상된 알고리즘임을 보인다.

• 전기학회논문지
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• 제59권10호
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• pp.1882-1888
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• 2010

It is widely known that ESA(Electric Signature Analysis) method is very useful one for fault diagnosis of an induction motor. Online fault diagnosis system of induction motors using LabVIEW is proposed to detect the fault of broken rotor bars and shorted turns in stator. This system is not model-based system of induction motor but LabVIEW-based fault diagnosis system using FFT spectrum of stator current in faulty motor without estimating of motor parameters. FFT of stator current in faulty induction motor is measured and compared with various reference fault data in data base to diagnose the fault. This paper is focused on to predict and diagnose of the health state of induction motors in steady state. Also, it can be given to motor operator and maintenance team in order to enhance an availability and maintainability of induction motors. Experimental results are demonstrated that the proposed system is very useful to diagnose the fault and to implement the predictive maintenance of induction motors.

• 대한전자공학회논문지
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• 제23권6호
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• pp.944-949
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• 1986

By improving the ability of arithmatic processing with an arithmatic processor in a microcomputer and realizing the data input system for real time analysis, an FFT analyzer that is usable within the range of audio frequency is designed and constructed. The input signal passes through a gain programmable pre-amplifier and anti-aliasing lowpass filter into an analogditital converter to be converted into digital form. The converted input data is processed by an Apple II microcomputer. The results of the processing are displayed using a microcomputer display unit and can be copied on a printer or stored in a floppy disk.

• 한국기계가공학회지
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• 제9권3호
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• pp.28-34
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• 2010

The suggested coupled system was analyzed using FRF and mode analysis. The eigen-mode of FRF analysis is consistent with that of conventional FFT in spectrum. Also, three numerical responses of second order system, which are coupled, was obtained using the Runge-Kutta Gill method. The displacement, velocity and acceleration response were calculated for the numerical analysis of coupled system and the displacement response was used for the calculation of FRF of this system. Using the mixed response of 1st and 2nd mode in example, the FRF was analysed for the analysis of mixed mode coupled system. Also, its mode shape was acquired by solving the eigen problem of coupled system.

• International Journal of Internet, Broadcasting and Communication
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• 제11권2호
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• pp.27-30
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• 2019

Factory monitoring systems are gaining importance in wide areas of industry. Especially, there have been many efforts in implementation of vibration measurement and analysis for monitoring the status of rotating machines. In this paper, a digital signal processor (DSP) based monitoring system dedicated to the vibration monitoring and analysis on rotating machines is discussed. Vibration signals are acquired and processed for the continuous monitoring of the machine status. Time domain signals and fast Fourier transform (FFT) are used for vibration analysis. All of the signal processing procedures are done in the DSP to reduce the production and maintenance cost. The developed system could also provide remote and mobile monitoring capabilities to operator via internet connection. This paper describes the overview of the functional blocks of the implemented system. Test results based on signals from small-size single phase motors are discussed for monitoring and defect diagnosis of the machine status.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1999년도 추계학술대회 논문집
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• pp.383-387
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• 1999

인간의 감성을 고려하는 제품의 생산에서 촉감은 인간이 제품을 만질 때 직접적으로 느낄 수 있는 중요한 감각이다. 이러한 촉감의 연구를 위해 직물을 대상으로 직물 표면의 거칠기를 측정하고 해석하였다. 측정된 표면 거칠기를 Fast Fourier Transform 변환하여 직물구조를 분석하는 기준으로 하였다. 각 peak 값들을 분석하여 나온 값이 직물 구조를 수식화하여 사용할 수 있는 좋은 방법이 됨을 알았다. 또한, 실의 잔털량을 측정하여, 잔털량과 인간의 주관적인 감각을 대표하는 값과의 상관관계를 조사하였다. 잔털량이 인간의 주관적인 감각을 객관적으로 표현할 수 있는 한 요소로 사용될 수 있다는 것을 확인하였다.