• Title/Summary/Keyword: Phase tracking algorithm

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A Simple Volume Tracking Method For Compressible Two-Phase Flow

  • SHYUE KEH-MING
    • Journal of The Korean Astronomical Society
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    • v.34 no.4
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    • pp.237-241
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    • 2001
  • Our goal is to present a simple volume-of-fluid type interface-tracking algorithm to compressible two-phase flow in two space dimensions. The algorithm uses a uniform underlying Cartesian grid with some cells cut by the tracked interfaces into two subcells. A volume-moving procedure that consists of two basic steps: (1) the update of volume fractions in each grid cell at the end of the time step, and (2) the reconstruction of interfaces from discrete set of volume fractions, is employed to follow the dynamical behavior of the interface motion. As in the previous work with a surface-tracking procedure for general front tracking (LeVeque & Shyue 1995, 1996), a high resolution finite volume method is then applied on the resulting slightly nonuniform grid to update all the cell values, while the stability of the method is maintained by using a large time step wave propagation approach even in the presence of small cells and the use of a time step with respect to the uniform grid cells. A sample preliminary numerical result for an underwater explosion problem is shown to demonstrate the feasibility of the algorithm for practical problems.

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Performance Analysis of Frequency Offset Compensation and Tracking Algorithms for HDR-WPAN System (HDR-WPAN 시스템을 위한 주파수 옵셋 보상과 트래킹 알고리즘 성능분석)

  • Park, Ji-Woo;Oh, Chang-Heon
    • Journal of Advanced Navigation Technology
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    • v.9 no.2
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    • pp.140-146
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    • 2005
  • In this paper, we proposed the frequency offset compensation algorithm and tracking algorithm which could improve the accumulated phase error for HDR-WPAN system. The proposed frequency offset compensation technique estimated each sample phase error by autocorrelation characteristics of CAZAC sequence, estimated phase error multiple each sample in a symbol, and finally compensated for the frequency offset. After frequency offset compensation using two steps, coarse and fine frequency offset, tracking algorithm have to use to compensate for the accumulated phase error. Because there is no pilot symbol in payload, more phase rotation occurred in received signal constellations due to the accumulated phase error as the payload length increase. Tracking algorithm compensates for a cumulative phase error ${\theta}$ between payload data.

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An algorithm for pahse detection using weighting function and the design of a phase tracking loop (가중치 함수를 이용한 위상 검출 알고리즘과 위상 추적 루프의 설계)

  • 이명환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.9A
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    • pp.2197-2210
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    • 1998
  • In the grand alliance (GA) HDTV receiver, a coherent detection is empolyed for coherent demodulation of vestigial side-band (VSB) signal by using frequency and phaselocked loop(FPLL) operating on the pilot carrier. Additional phase tracking loop (PTL) employed to track out phase noise that has not been removed by the FPLL in theGA system. In this paper, we propose an algorithm for phase detection which utilizes a weighting function. The simplest implementation of the proposed algorithm using te sign of the Q channel component can be tractable by imposing a phase detection gain to the loop gain. It is obserbed that the propsoed algorithm has a robust characteristic against the performance of the digital filters used for Q channel estimation. A second goal of this paper is to introduce a gain control algorithm for the PTL in order to provide an effective implementation of the proposed phase detection algorithm. And we design the PTL through the realization of the simplified digital filter for H/W reduction. The proposed algorithms and the designed PTL are evaluated by computer simulation. In spite of using the simplified H/W structure, simulation results show that the proposed algorithms outperform the coventional PTL algorithms in the phase detection and tracking performance.

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A Method of Lane Marker Detection Robust to Environmental Variation Using Lane Tracking (차선 추적을 이용한 환경변화에 강인한 차선 검출 방법)

  • Lee, Jihye;Yi, Kang
    • Journal of Korea Multimedia Society
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    • v.21 no.12
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    • pp.1396-1406
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    • 2018
  • Lane detection is a key function in developing autonomous vehicle technology. In this paper, we propose a lane marker detection algorithm robust to environmental variation targeting low cost embedded computing devices. The proposed algorithm consists of two phases: initialization phase which is slow but has relatively higher accuracy; and the tracking phase which is fast and has the reliable performance in a limited condition. The initialization phase detects lane markers using a set of filters utilizing the various features of lane markers. The tracking phase uses Kalman filter to accelerate the lane marker detection processing. In a tracking phase, we measure the reliability of the detection results and switch it to initialization phase if the confidence level becomes below a threshold. By combining the initialization and tracking phases we achieved high accuracy and acceptable computing speed even under a low cost computing resources in which we cannot use the computing intensive algorithm such as deep learning approach. Experimental results show that the detection accuracy is about 95% on average and the processing speed is about 20 frames per second with Raspberry Pi 3 which is low cost device.

Active Tonal Noise Canceller with Frequency Tracking

  • Na, Hee-Seung;Park, Young-Jin
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.1E
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    • pp.84-88
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    • 1996
  • In this paper, we propose a novel adaptive digital filter for tonal noise cancellation, with a frequency tracking capability. The proposed algorithm not only estimates the magnitude and phase of the tonal disturbance but also tracks its frequency, which changes in quasi-static manner. The algorithm uses the steepest descent method and the instantaneous frequency approach for the phase/magnitude estimation and frequency tracking, respectively. A number of computer simulations have been carried out in order to demonstrate the feasibility of the proposed ANC algorithm under various conditions.

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A Maximum Power Control of IPMSM with Real-time Parameter Identification

  • Jun, Hyunwoo;Ahn, Hanwoong;Lee, Hyungwoo;Go, Sungchul;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.110-116
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    • 2017
  • This paper proposed a new real-time parameter tracking algorithm. Unlike the convenience algorithms, the proposed real-time parameter tracking algorithm can estimate parameters through three-phase voltage and electric current without coordination transformation, and does not need information on magnetic flux. Therefore, it can estimate parameters regardless of the change according to operation point and cross-saturation effect. In addition, as the quasi-real-time parameter tracking technique can estimate parameters through the four fundamental arithmetic operations instead of complicated algorithms such as numerical value analysis technique and observer design, it can be applied to low-performance DSP. In this paper, a new real-time parameter tracking algorithm is derived from three phase equation. The validity and usefulness of the proposed inductance estimation technique is verified by simulation and experimental results.

Efficient Tracking of Speech Formant Using Closed Phase WRLS-VFF-VT Algorithm

  • Lee, Kyo-Sik;Park, Kyu-Sik
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.2E
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    • pp.8-13
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    • 2000
  • In this paper, we present an adaptive formant tracking algorithm for speech using closed phase WRLS-VFF-VT method. The pitch synchronous closed phase methods is known to give more accurate estimates of the vocal tract parameters than the pitch asynchronous method. However the use of a pitch-synchronous closed phase analysis method has been limited due to difficulties associated with the task of accurately isolating the closed phase region in successive periods of speech. Therefore we have implemented the pitch synchronous closed phase WRLS-VFF-VT algorithm for speech analysis, especially for formant tracking. The proposed algorithm with the variable threshold(VT) can provide a superior performance in the boundary of phone and voiced/unvoiced sound. The proposed method is experimentally compared with the other method such as two channel CPC method by using synthetic waveform and real speech data. From the experimental results, we found that the block data processing techniques, such as the two-channel CPC, gave reasonable estimates of the formant/antiformant. However, the data windows used by these methods included the effects of the periodic excitation pulses, which affected the accuracy of the estimated formants. On the other hand the proposed WRLS-VFF-VT method, which eliminated the influence of the pulse excitation by using an input estimation as part of the algorithm, gave very accurate formant/bandwidth estimates and good spectral matching.

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The Instantaneous Phase-Tracking in PLL using the DFT Algorithm (DFT 알고리즘을 이용한 PLL의 순시 추종)

  • Kim, Youn-Seo;Yang, Oh
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.6
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    • pp.141-148
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    • 2008
  • An utility voltage information, including the frequency, phase angle and amplitude is very important in many industrial systems. The grid-connected photovoltaic system in the limelight as alternative energy needs utility voltage information such as frequency, phase angle and magnitude to connect the grid-line. In this paper, it proposes the instantaneous phase-tracking in PLL that uses the frequency from the utility voltage as a sync signal and locks the phase with compensation for phase difference from DPT algorithm. It also proposes not only DFT algorithm execution by every sample not by one period, but also phase-tracking method in a wide range of frequency not a fixed one. This paper shows the feasibility and the usefulness of the proposed methods through the computer simulation and the experiment.

Train Tracking System Using Phase Difference of Arrival (도달 위상차를 이용한 열차 위치 추적)

  • Chung Sang-ki;Cho Hong-Shik;Kim Yeon-Su;Jeong Rag-Gyo
    • Journal of the Korean Society for Railway
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    • v.8 no.3
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    • pp.244-252
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    • 2005
  • Accurate and reliable tracking of train is essential for a train control system. The fixed block system which utilizes the track circuit has been used widely for detecting train position. As an alternative, the moving block system has the advantage over the fixed block system since it enables shorter headway and easier maintenance. This paper presents a new technique for the train tracking system which uses radio signal for the train position detection. The proposed algorithm uses the phase difference of arrival of radio signal for the detection of train position. Experimental verification of the algorithm is presented in the paper.

Multiple Cues Based Particle Filter for Robust Tracking (다중 특징 기반 입자필터를 이용한 강건한 영상객체 추적)

  • Hossain, Kabir;Lee, Chi-Woo
    • Proceedings of the Korea Information Processing Society Conference
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    • 2012.11a
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    • pp.552-555
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    • 2012
  • The main goal of this paper is to develop a robust visual tracking algorithm with particle filtering. Visual Tracking with particle filter technique is not easy task due to cluttered environment, illumination changes. To deal with these problems, we develop an efficient observation model for target tracking with particle filter. We develop a robust phase correlation combined with motion information based observation model for particle filter framework. Phase correlation provides straight-forward estimation of rigid translational motion between two images, which is based on the well-known Fourier shift property. Phase correlation has the advantage that it is not affected by any intensity or contrast differences between two images. On the other hand, motion cue is also very well known technique and widely used due to its simplicity. Therefore, we apply the phase correlation integrated with motion information in particle filter framework for robust tracking. In experimental results, we show that tracking with multiple cues based model provides more reliable performance than single cue.