• Title/Summary/Keyword: energy separation algorithm

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Frequency/Amplitude Separation Algorithm Using the Higher Order Differential Energy Operator and Its Application (고차의 미분에너지함수를 이용한 주파수 및 진폭성분 추출 알고리즘과 응용)

  • Iem, Byeong-Gwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.8
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    • pp.1498-1502
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    • 2007
  • There have been many different definitions of energy functions as the second statistics of a signal. In this paper, using the higher order differential energy function, we propose an algorithm separating the amplitude and frequency components in a discrete sinusoidal signal. The proposed amplitude and frequency estimation methods have less computational requirement than the existing methods. It also shows large computational advantage over the root mean square (RMS) calculation of a signal. The proposed methods can be used in the detection of abnormal events in signals on the power line. Computer simulations show that proposed frequency estimation method can detect the presence of voltage increase or decrease for a short period of time. Also, the proposed estimation methods have been compared with existing methods in terms of estimation error variance.

Prediction of Turbulent Flows with Separation and Swirl Using the RNG K-$\varepsilon$ Turbulence Model (RNG k-$\varepsilon$ 난류모델을 이용한 유동박리 및 선회를 가지는 난류유동의 예측)

  • 김성구;오군섭;김용모;이창식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.5
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    • pp.119-129
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    • 1996
  • This study is concerned with the critical evaluation of predicative capability of a k-$\varepsilon$ turbulence model using the Renormalization Group(RNG) theory. The present numerical model for solution of the Navier-Stokes System is based on the modified PISO algorithms. Computations have been performed with the RNG-based K-$\varepsilon$ model for the two-dimensional flow over a backward-facing step, a confined coaxial jet, and a swirling flow in a swirl combustor. Numerical results are compared with experimental data in terms of mean flow velocities, turbulent kinetic energy, and turbulent stresses. Numerical results clearly indicate that the RNG-based K-$\varepsilon$ turbulence model shows a significant improvement over a standard K-$\varepsilon$ model in predicting the turbulent flows with flow separation and swirl.

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Clarifying Warhead Separation from the Reentry Vehicle Using a Novel Tracking Algorithm

  • Liu Cheng-Yu;Sung Yu-Ming
    • International Journal of Control, Automation, and Systems
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    • v.4 no.5
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    • pp.529-538
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    • 2006
  • Separating a reentry vehicle into warhead and body is a conventional and efficient means of producing a huge decoy and increasing the kinetic energy of the warhead. This procedure causes the radar to track the body, whose radar cross section is larger, and ignore the warhead, which is the most important part of the reentry vehicle. However, the procedure is difficult to perform using standard tracking criteria. This study presents a novel tracking algorithm by integrating input estimation and modified probabilistic data association filter to solve this difficulty in a clear environment. The proposed algorithm with a new defined association probability in this filter provides a good tracking capability for the warhead ignoring the radar cross section. The simulation results indicate that the errors between the estimated and the warhead trajectories are reduced to a small interval in a short time. Therefore, the radar can produce a beam to illuminate to the right area and keep tracking the warhead all the way. In conclusion, this algorithm is worthy of further study and application.

Pervaporation Characteristics of Water/Ethanol and Water/Isopropyl Alcohol Mixtures through Zeolite 4A Membranes: Activity Coefficient Model and Maxwell Stefan Model (제올라이트 4A 분리막을 이용한 물/에탄올, 물/이소프로필알코올 혼합물의 투과증발 특성 연구 : 활동도계수모형 및 Generalized Maxwell Stefan 모형)

  • Oh, Woong Jin;Jung, Jae-Chil;Lee, Jung Hyun;Yeo, Jeong-gu;Lee, Da Hun;Park, Young Cheol;Kim, Hyunuk;Lee, Dong-Ho;Cho, Churl-Hee;Moon, Jong-Ho
    • Clean Technology
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    • v.24 no.3
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    • pp.239-248
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    • 2018
  • In this study, pervaporation experiments of water, ethanol and IPA (Isopropyl alcohol) single components and water/ethanol, water/IPA mixtures were carried out using zeolite 4A membranes developed by Fine Tech Co. Ltd. Those membranes were fabricated by hydrothermal synthesis (growth in hydrothermal condition) after uniformly dispersing the zeolite seeds on the tubular alumina supports. They have a pore size of about $4{\AA}$ by ion exchange of $Na^+$ to the LTA structure with Si/Al ratio of 1.0, and shows strong hydrophilic property. Physical characteristics of prepared membranes were evaluated by using SEM (surface morphology), porosimetry (macro- or meso- pore analysis), BET (micropore analysis), and load tester (compressive strength). Pervaporation experiments with various temperature and concentration conditions confirmed that the zeolite 4A membrane can selectively separate water from ethanol and IPA. Water/ethanol separation factor was over 3,000 and water/IPA separation factor was over 1,500 (50 : 50 wt%, initial feed concentration). Pervaporation behaviors of single components and binary mixtures were predicted using ACM (activity coefficient model), GMS (generalized Maxwell Stefan) model and DGM (Dusty Gas Model). The adsorption and diffusion coefficients of the zeolite top layer were obtained by parameter estimation using GA (Genetic Algorithm, stochastic optimization method). All the calculations were carried out using MATLAB 2018a version.

Digital Demodulator Design and Characteristics Using Algebraic Separation and Energy Operator from Undersampled Two-Component AM-FM Signals (저표본화된 주성분의 AM-FM 신호들로부터 대수적 분리와 에너지 연산자를 사용한 복조기 설계 및 특성)

  • Sohn, Tae-Ho;Lee, Min-Ho
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.5
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    • pp.643-649
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    • 1999
  • In this paper, we proposed that i) noise-tolerant four kinds of AM(Amplitude Modulation)-FM(Frequency Modulation) demodulators are designed, ⅱ) we derived undersampling frequency through the product via energy operator of the monocomponent AM-FM signals separated form two-component AM-FM signals, and ⅲ) these four kinds of AM-FM demodulators detect respectively information signals of the IA(Instantaneous Amplitude) and IF(Instantaneous Frequency) by undersampling frequency to be different each other from the undersampled monocomponet AM-FM signals. Particularly, the proposed algorithm can control undersampling frequency by an integer factor. And these efficient AM-FM demodulators are well worked with the undersampled AM-FM signals.

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A broadband detection algorithm using cross-correlation of two split beams for cylindrical array sonar (원통형 배열 소나를 위한 두 개의 분리 빔의 상호상관을 이용한 광대역탐지 기법)

  • Kwak, ChulHyun
    • The Journal of the Acoustical Society of Korea
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    • v.36 no.5
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    • pp.300-304
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    • 2017
  • In a cylindrical sonar, a conventional broadband energy detector has limitations in the separation of adjacent targets. In this paper, a broadband detection algorithm using cross-correlation is applied to the cylindrical sonar to improve the bearing resolution. The proposed algorithm uses split beamforming before broadband detection processing using cross-correlation to generate half beams. The time delay obtained from the peak of correlation between half beams is used to estimate the bearing of target. Simulations demonstrate the improved performance of the proposed algorithm against the conventional algorithm.

A Study on Measurement of Voltage Parameters using TEO&DESA in Auto-synchronizer (TEO&DESA를 활용한 Auto-synchronizer의 전압 파라미터 측정에 관한 연구)

  • Shin, Hoon-Chul;Han, Soo-Kyeong;Lyu, Joon-Soo;Cho, Soo-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.7
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    • pp.816-823
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    • 2018
  • The Auto-synchronizer is essential equipment for synchronizing a generator to the power system. It is performing that measurement of the magnitude, frequency and phase of the voltage signal of the power system and generator. It is important to select the appropriate measurement algorithm for preventing various problem such as mechanical stress and Electrical problem. Teager Energy Operator(TEO) and Discrete separation algorithm(DESA) is measurable the instantaneous parameters of a sine wave using 5 samples and can be measured at a fast and with a simple operation. Therefore it has many advantages in measuring the parameters. In this paper, it confirmed measurement results using matlab simulations when there are synchronized in order of frequency, magnitude. Also it presented methods using digital filters and sample intervals to improve accuracy.

Numerical optimization of Wells turbine for wave energy extraction

  • Halder, Paresh;Rhee, Shin Hyung;Samad, Abdus
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.9 no.1
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    • pp.11-24
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    • 2017
  • The present work focuses multi-objective optimization of blade sweep for a Wells turbine. The blade-sweep parameters at the mid and the tip sections are selected as design variables. The peak-torque coefficient and the corresponding efficiency are the objective functions, which are maximized. The numerical analysis has been carried out by solving 3D RANS equations based on k-w SST turbulence model. Nine design points are selected within a design space and the simulations are run. Based on the computational results, surrogate-based weighted average models are constructed and the population based multi-objective evolutionary algorithm gave Pareto optimal solutions. The peak-torque coefficient and the corresponding efficiency are enhanced, and the results are analysed using CFD simulations. Two extreme designs in the Pareto solutions show that the peak-torque-coefficient is increased by 28.28% and the corresponding efficiency is decreased by 13.5%. A detailed flow analysis shows the separation phenomena change the turbine performance.

Numerical analysis of the differential pressure venturi-cone flowmeter (차압식 벤튜리콘 유량계에 대한 유동해석)

  • 윤준용;맹주성;이정원
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.6
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    • pp.714-720
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    • 1998
  • The differential pressure venturi-cone flowmeter is an advanced flowmeter which has many advantages such as wide range of measurement, high accuracy, excellent flow turn-down ratio, low headless, short installation pipe length requirement, and etc. Like other differential pressure flowmeters, the venturi-cone flowmeter uses the law of energy conservation, but its shape and position make it perform better than others. The cone acts as its own flow conditioner and mixer, fully conditioning and mixing the flow prior to measurement. For the analysis, we used Reynolds-averaged Wavier-Stokes equations and k-$\omega$ turbulence model. The equations were fully transformed into the computational domain, the pressure-velocity coupling was made through SIMPLER algorithm, and the equations were discretized using finite analytic solutions of the liberalized equations(Finite Analytic Method). To control the separation phenomenon on the cone surface, we proposed a new shape of cone, and analyzed the flowfield in the new flowmeter system, and found the improvement on the performance of the new cone flowmeter.

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An Active Contour Approach to Extract Feature Regions from Triangular Meshes

  • Min, Kyung-Ha;Jung, Moon-Ryul
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.3
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    • pp.575-591
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    • 2011
  • We present a novel active contour-based two-pass approach to extract smooth feature regions from a triangular mesh. In the first pass, an active contour formulated in level-set surfaces is devised to extract feature regions with rough boundaries. In the second pass, the rough boundary curve is smoothed by minimizing internal energy, which is derived from its curvature. The separation of the extraction and smoothing process enables us to extract feature regions with smooth boundaries from a triangular mesh without user's initial model. Furthermore, smooth feature curves can also be obtained by skeletonizing the smooth feature regions. We tested our algorithm on facial models and proved its excellence.