• Title/Summary/Keyword: 신호처리(signal processing)

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Development of Photoacoustic System for Breast Cancer Detection (유방암 진단용 광음향 영상 시스템 개발)

  • Lee, Soonhyouk;Ji, Yun-Seo;Lee, Rena
    • Progress in Medical Physics
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    • v.24 no.3
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    • pp.183-190
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    • 2013
  • Recently, the photoacoustic imaging system has been widely and intensively developed, and has been shown the possibility of diagnosis for early stage cancer. In this study, we developed a photoacoustic tomography imaging system with a commercial ultra sound device and a linear array probe. A tube phantom and a chicken breast phantom was made for the possibility of a system as a breast cancer detection. A moving average filter and a band pass filter with 3~6 MHz bandwidth were developed for background noise elimination before delay-and-sum beamforming algorithm was used for image reconstruction. As a result, we showed that some signal processing procedure before beamforming was effective for the photoacoustic image reconstruction.

A Study on the Characteristics Improvement of Chebyshev Filter Function (Chebyshev 필터 함수의 특성 개선에 관한 연구)

  • You, Jae-Hoon;Choi, Seok-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.753-759
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    • 2020
  • A modified Chebyshev lowpass filter function with progressively diminishing ripples in the passband is proposed and analyzed in the frequency domain. Owing to the diminishing ripples, the passband magnitude characteristic of the proposed Chebyshev function has improved compared to the classical Chebyshev function. In addition, the phase characteristics of the proposed Chebyshev function were improved considerably compared to that of the Chebyshev function, and the time delay of the proposed function was much simpler and flatter. In addition, the proposed Chebyshev filter was realizable by the passive doubly terminated ladder network delivering maximum power transfer for the order n, even or odd, thus making themselves amenable to low-sensitivity active RC or switched capacitor filters through the simulation techniques. To verify the proposed Chebyshev filter characteristics, a 6th order passive doubly terminated ladder lowpass filter was designed and analyzed using the MATLAB and SPICE program. Thus, the proposed Chebyshev function can remove the drawbacks of the classical Chebyshev function and could be applicable to the design of a filter with an improved filter size, phase, and time delay characteristics for various signal processing.

A Research on the FCB Detection Algorithm for the GSM Mobile System (GSM 무선시스템에서 주파수정정 버스트 (FCB) 검출 알고리즘에 관한 연구)

  • 김범진;한재충;홍승억
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.12A
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    • pp.1876-1882
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    • 1999
  • In this paper, we have proposed a FCB detection algorithm for the GSM system which is european cellular standard. The detection algorithm can be implemented using received signal sampler, correlator, and post detection combiner. GSM mobile phone can use the proposed algorithm for detection of the Broadcasting Channel, and to obtain the initial timing estimate. The proposed algorithm has a architecture which is suitable for DSP or ASIC implementation, and required memory size is small. The performance of the algorithm is a function of the processing data window size and the threshold values. Proper window size and the threshold values can be determined by analyzing the correlator and combiner. The proposed algorithm has been implemented using DSP, and the performance was verified using baseband simulation. The simulation assumed frequency offset values of 0ppm and 15ppm with the receiver filter bandwidth set at both minimum and maximum. It is shown that the algorithm is robust under various assumptions, and suitable for real implementations.

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Flame and Smoke Detection for Early Fire Recognition (조기 화재인식을 위한 화염 및 연기 검출)

  • Park, Jang-Sik;Kim, Hyun-Tae;Choi, Soo-Young;Kang, Chang-Soon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.427-430
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    • 2007
  • Many victims and property damages are caused in fires every year. In this paper, flame and smoke detection algorithm by using image processing technique is proposed to early alarm fires. The first decision of proposed algorithms is to check candidate of flame region with its unique color distribution distinguished from artificial lights. If it is not a flame region then we can check to candidate of smoke region by measuring difference of brightness and chroma at present frame. If we just check flame and smoke with only simple brightness and hue, we will occasionally get false alarms. Therefore we also use motion information about candidate of flame and smoke regions. Finally, to determine the flame after motion detection, activity information is used. And in order to determine the smoke, edges detection method is adopted. As a result of simulation with real CCTV video signal, it is shown that the proposed algorithm is useful for early fire recognition.

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Adjacent to the Highway Intersection, According to the Disaster, the Optimal Operating (고속도로 재난/재해에 따른 인접교차로 최적 운영방안)

  • Kang, Jin-Woong;Kwon, Young-Hyuk;Lee, Mun-Young;Choi, Jae-Young;Kum, Ki-Jung
    • International Journal of Highway Engineering
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    • v.14 no.3
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    • pp.87-96
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    • 2012
  • This research overcomes limit of prevention of disasters connection manual that was stopping in existing administrative formality presentation, and allowed purpose in substantial prevention of disasters countermeasure presentation through powerful engineering access. Did operation plan manual Tuesday in contiguity crossing that can reduce confusion by vehicleses that detour by contiguity IC of disaster point to do unusualness ashes in freeway section for this and solve jam-up phenomenon that occur by processing way insufficiency for roundabout way vehicles when happen. Metropolitan areas to target type classification in the highway along the highway adjacent to the intersection at Main Line Blocking optimum operating point analysis and an analysis of countermeasures in case of disaster, the lower the road entering the highway depending on the type of operating at the intersection were different. Depending on the results of analysis, while each point of a disaster, according to the characteristics of geometric conditions, traffic conditions, identify and determine the operating room and the adjacent intersection of media, and building systems to promote the driver if the quick initial response from the impending disaster situations and the safety of drivers can be considered secure.

Study on Estimation of PM Mass in DPF from Pressure Drop in 3L Diesel Engine (3L급 디젤엔진의 배압이용 DPF 매연포집량 예측에 대한 연구)

  • Kim, Hong-Suk;Lee, Jin-Wook
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.5
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    • pp.499-504
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    • 2010
  • It is important to determine the exact soot mass in a DPF system in order to control the timing of PM regeneration. The soot mass accumulated in a filter can be estimated from the pressure drop in the filter and the exhaust gas flow rates. In this study, the soot index is defined as the pressure drop in the DPF divided by the pressure drop in a DOC. An effective signal processing method for determining the soot index is proposed; the results yielded by this method indicate good correlation between the soot index and the amount of soot loaded into the filter for both steady-state and transient-state operating conditions in a 3L diesel engine for passenger vehicles.

Measurements of Ultrasonic Velocity and Attenuation by Signal Processing Techniques in Time and Frequency Domains (시간 및 주파수 영역에서의 신호 처리 기술에 의한 초음파 속도와 감쇠의 측정)

  • Jang, Young-Su;Kim, Jin-Ho;Jeong, Hyun-Jo;Nam, Young-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.19 no.2
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    • pp.118-128
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    • 1999
  • There are many ultrasonic measurement methods that are used in nondestructive testing applications. Some typical applications include material property determination, microstructural characterization. and flaw detection. Ultrasonic parameters such as velocity and attenuation are most commonly required in these applications. The accuracy and repeatability of testing results are dependent on both the hardware used to generate and receive the ultrasonic waves and on the analysis software for calculating these parameters. In this study, five analysis algorithms were implemented on a computer for measuring wave speed in a pulse echo. immersion testing configuration. In velocity measurements comparisons were made between the overlap. cross-correlation. Fourier transform. Hilbert transform, wavelet transform algorithms. Velocity measurement was applied to an isotropic steel sample using the five analysis algorithms. Frequency-dependent phase/group velocity and attenuation were also measured using the Fourier transform and wavelet transform algorithms on a composite laminate containing voids.

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Development of Double Rotation C-Scanning System and Program for Under-Sodium Viewing of Sodium-Cooled Fast Reactor (소듐냉각고속로 소듐 내부 가시화를 위한 이중회전구동 C-스캔 시스템 및 프로그램 개발)

  • Joo, Young-Sang;Bae, Jin-Ho;Park, Chang-Gyu;Lee, Jae-Han;Kim, Jong-Bum
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.4
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    • pp.338-344
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    • 2010
  • A double rotation C-scanning system and a software program Under-Sodium MultiVIEW have been developed for the under-sodium viewing of a reactor core and in-vessel structures of a sodium-cooled fast reactor KALIMER-600. Double rotation C-scanning system has been designed and manufactured by the reproduction of double rotation plug of a reactor head in KALIMER-600. Hardware system which consists of a double rotating scanner, ultrasonic waveguide sensors, a high power ultrasonic pulser-receiver, a scanner driving module and a multi channel A/D board have been constructed. The functions of scanner control, image mapping and signal processing of Under-Sodium MultiVIEW program have been implemented by using a LabVIEW graphical programming language. The performance of Under-Sodium MultiVIEW program was verified by a double rotation C-scanning test in water.

A Study on Multi Target Elevation Angle Estimation of Hight Directivity using Multi Stacked Beam Forming (다중 스택 빔 형성을 이용한 고 지향성의 다중 목표물 고각 추정에 대한 연구)

  • Lee, Kwan-Hyeong;Song, Woo-Young;Lee, Myung-Ho
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.8
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    • pp.129-135
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    • 2011
  • In this paper, we propose a multi target's elevation angle estimation method using multi beam forming technique. This method make a stacked beam to digital processing a received signal in array element. There can be desired receiving beam to application weight value at antenna element in beam forming. Currently, we are to make multi stacked beam using fast fourier transform in stead of phase shifter to be a computer performance much improvement. Also, we improve multi beam directivity using beam steering error correction technique in order to beam steering to desired direction in receiver. Through simulation, we show that the proposed elevation estimation method based on fast fourier transform and beam steering error correction technique, improves th performance of target estimation compared to previous method.

A Study on the Adaptive Technique for Artifact Cancelling in Electroencephalogram Analysis System (뇌파 분석 시스템에서의 Artifact 제거를 위한 적응 기법에 관한 연구)

  • 유선국;김기만;남기현
    • Journal of Biomedical Engineering Research
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    • v.18 no.4
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    • pp.389-396
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    • 1997
  • Several types of electrical artifact seen on electroencephalogram( EEG) records are described. Those are the EOG and the PVC roller pump noise, and so on. An adaptive digital filtering of the electroencephalogram( EEG) is a successful way of suppressing mains interference, but it affects some of the frequency components of the signal, whore artifacts may not be acceptable in some cafes of automatic EEG processing. Thus we studied the method for cancelling these artifacts. This proposed method does not use the reference channel, and is realized by connecting the linear predictor and the fixed FIR filter for the EOG artifact, and by cascading the linear predictor and the noise canceller for the pump artifact. The simulation results illustrate the performances of the proposed method in terms of the capability of interferences suppression. In the results we obtained about 20 dB noise reduction.

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