• Title/Summary/Keyword: weighting factor

Search Result 323, Processing Time 0.12 seconds

The Comparison of the Adaptive Equalization Performance in MCMA Algorithm by the Weighting Factor (MCMA알고리즘에서 weighting factor에 의한 적응 등화 성능 비교)

  • Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
    • /
    • v.10 no.4
    • /
    • pp.137-143
    • /
    • 2010
  • This paper deals with the performance comparison of self adaptive equalizer by the weighting factor of MCMA cost function for the compensate the amplitude and phase distortion which occurs in the communication channel. The MCMA is improves the cost function of present CMA at the output of equalizer for the minimize of error function in the amplitude and phase, the value of weighting factor is used at this time. When the comparison of equalizer performance, we classified to initial state and steady state, then it represents the convergence time and convergence speed and steady state operation of equalizer to the predetermined level, it is determined by the weighting factor. We confirm to the different result to this 2 state by weighting factor values using computer simulation. By using the result of this paper, if we appropriately choose the weighting factor values in the environment of communication channel, it is expected that the high quality digital transmission is possible.

New Weighting Factor of 2D Isotropic-Dispersion Finite Difference Time Domain(ID-FDTD) Algorithm

  • Zhao, Meng;Koh, Il-Suek
    • Journal of electromagnetic engineering and science
    • /
    • v.8 no.4
    • /
    • pp.139-143
    • /
    • 2008
  • In this paper, a new scheme to calculate the weighting factor of the 2-D isotropic-dispersion finite difference time domain(ID-FDTD) is proposed. The weighting factor in [1] was formulated in free space, so that it may not be optimal in dielectric media. Therefore, the weighting factor was reformulated by considering the material properties and using the least mean square method. As a result, a minimum numerical dispersion error for any dielectric media is guaranteed.

Imposed Weighting Factor Optimization Method for Torque Ripple Reduction of IM Fed by Indirect Matrix Converter with Predictive Control Algorithm

  • Uddin, Muslem;Mekhilef, Saad;Rivera, Marco;Rodriguez, Jose
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.1
    • /
    • pp.227-242
    • /
    • 2015
  • This paper proposes a weighting factor optimization method in predictive control algorithm for torque ripple reduction in an induction motor fed by an indirect matrix converter (IMC). In this paper, the torque ripple behavior is analyzed to validate the proposed weighting factor optimization method in the predictive control platform and shows the effectiveness of the system. Therefore, an optimization method is adopted here to calculate the optimum weighting factor corresponds to minimum torque ripple and is compared with the results of conventional weighting factor based predictive control algorithm. The predictive control algorithm selects the optimum switching state that minimizes a cost function based on optimized weighting factor to actuate the indirect matrix converter. The conventional and introduced weighting factor optimization method in predictive control algorithm are validated through simulations and experimental validation in DS1104 R&D controller platform and show the potential control, tracking of variables with their respective references and consequently reduces the torque ripple.

Error Analysis of Muskingum-Cunge Flood Routing Method (Muskingum-Cunge 홍수추적 방법의 오차해석)

  • Kim, Dae-Geun;Seo, Il-Won
    • Journal of Korea Water Resources Association
    • /
    • v.36 no.5
    • /
    • pp.751-760
    • /
    • 2003
  • Error analysis of finite difference equation on the Muskingum-Cunge flood routing method with free time and space weighting factor was carried out. The error analysis shows that the numerical solution of the Muskingum-Cunge method becomes diverged with time when the sum of time weighting factor and space weighting factor is greater than 1.0. Numerical diffusion increases when the sum of time weighting factor and space weighting factor decreases. Numerical diffusion and numerical oscillation increase when the grid resolution is coarse. Numerical experiments and field applications show that the Muskingum-Cunge method with free space weighting factor is more effective for simulating the flood routing with great peak diminution than conventional Muskingum-Cunge method with fixed space weighting factor, 0.5.

Analysis of the Typical Meteorological Data and the Weighting Factor of TRY (표준기상데이터 형식 분석 및 TRY 가중치 적용)

  • Yoo, Ho-Chun;Lee, Gwan-ho;Park, So-Hee;Kim, Kyoung-Ryul
    • Journal of the Korean Solar Energy Society
    • /
    • v.27 no.4
    • /
    • pp.157-165
    • /
    • 2007
  • Typical meteorological data is fundamental to computer simulation introduced for environment-friendly architecture designs. Therefore, in order to improve accuracy of computer simulation, typical meteorological data should be established. By examining how to choose typical meteorological data, this study selected the optimized weight factor for TRY where weighting factor was not clearly set. As a result, the same weighting factor was applied to each climatic element and TRY data where the weight factor was applied could have the distribution very similar to measurement data. The weighting factor is considered to reflect geographical characteristics of Seoul and applied climatic elements.

Digital Watermarking Based on Adaptive Threshold and Weighting Factor Decision Method (적응적 임계치와 가중치 결정 방법에 기반한 디지털 워터마킹)

  • Lim, Ho;Kim, Jin-Young
    • Proceedings of the IEEK Conference
    • /
    • /
    • pp.123-126
    • /
    • 2000
  • In this paper, we propose new watermarking technique using weighting factor decision method in the watermark embedding step and adaptive threshold decision method in the watermark extracting step. In our method, we are determined weighting factor in simple by calculating distance between pixel coefficient and neighborhood pixel coefficients and threshold is adaptively determined by searching the minimized extract error value using histogram of difference value.

  • PDF

Uncertainty Evaluation of Velocity Integration Method for 5-Chord Ultrasonic Flow Meter Using Weighting Factor Method (가중계수법을 이용한 5회선 초음파 유량계의 유속적분방법의 불확도 평가)

  • Lee, Ho-June;Lee, Kwon-Hee;Noh, Seok-Hong;Hwang, Sang-Yoon;Noh, Young-Ah
    • 유체기계공업학회:학술대회논문집
    • /
    • /
    • pp.287-294
    • /
    • 2005
  • Flow rate measurement uncertainties of the ultrasonic flow meter are generally influenced by many different factors, such as Reynolds number, flow distortion, turbulence intensity, wall surface roughness, velocity integration method along the acoustic paths, and transducer installation method, etc. Of these influencing factors, one of the most important uncertainties comes from the velocity integration method. In the present study, a optimization weighting factor method for 5-chord, which is given by a function of the chord locations of acoustic paths, is employed to obtain the mean velocity in the flow through a pipe. The power law profile is assumed to model the axi-symmetric pipe flow and its results are compared with the present weighting factor concept. For an asymmetric pipe flow, the Salami flow model is applied to obtain the velocity profiles. These theoretical methods are also compared with the previous Gaussian, Chebyshev, and Tailor methods. The results obtained show that for the fully developed turbulent pipe flows with surface roughness effects, the present weighting factor method is much less sensitive than Chebyshev and Tailor methods, leading to a better reliability in flow rate measurement using the ultrasonic flow meters.

  • PDF

Formation Flight and Collision Avoidance for Multiple UAVs using Concept of Elastic Weighting Factor

  • Kang, Seunghoon;Choi, Hyunjin;Kim, Youdan
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.14 no.1
    • /
    • pp.75-84
    • /
    • 2013
  • In this paper, the guidance law for formation flight and collision avoidance of multiple Unmanned Aerial Vehicle (UAV)s is proposed. To construct the physically comprehensible guidance law for formation flight, the virtual structure approach is used. To develop a guidance law for collision avoidance considering both other UAVs and unknown static obstacles, a geometric approach using information such as a relative position vector is utilized. Through the Lyapunov theorem, the stability of the proposed guidance law is proved. To combine guidance commands, the concept of the elastic weighting factor inspired by the elastic behavior of shape memory polymer, which tends to regain its original shape after deformation, is introduced. By using the concept of elastic weighting factor, multiple UAVs are able to cope actively with the situation of a collision between both UAVs and static obstacles during the formation flight. To verify the performance of the proposed method, numerical simulations are performed.

Model Predictive Torque Control of Surface Mounted Permanent Magnet Synchronous Motor Drives with Voltage Cost Functions

  • Zhang, Xiaoguang;Hou, Benshuai;He, Yikang;Gao, Dawei
    • Journal of Power Electronics
    • /
    • v.18 no.5
    • /
    • pp.1369-1379
    • /
    • 2018
  • In this paper, a model predictive torque control (MPTC) without the use of a weighting factor for surface mounted permanent-magnet synchronous machine (SPMSM) drive systems is presented. Firstly, the desired voltage vector is predicted in real time according to the principles of deadbeat torque and flux control. Then the sector of this desired voltage vector is determined. The complete enumeration for testing all of the feasible voltage vectors is avoided by testing only the candidate vectors contained in the sector. This means that only two voltage vectors in the sector need to be tested for selecting the optimal voltage vector in each control period. Thus, the calculation time can be reduced when compared with the conventional enumeration method. On the other hand, a novel cost function that only includes the dq-axis voltage errors between the desired voltage and candidate voltage is designed to eliminate the weighting factor used in the conventional MPTC. Thus, the control complexity caused by the tuning of the weighting factor is effectively decreased when compared with the conventional MPTC. Simulation and experimental investigation have been carried out to verify the proposed method.

Calculation of the Absorption Coefficient and Weighting Factor Expressing the Total Emissivity of Flame (화염의 총괄폭사 계수를 나타내는 급수계수 및 가중치의 계산)

  • 하만영;허병기
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.10 no.1
    • /
    • pp.121-130
    • /
    • 1986
  • Using the sbsorption coefficients and the weighting factors of the gray gas, the total emissivities of C $O_{2}$- $H_{2}$O and C $O_{2}$- $H_{2}$O- transient species-soot gas mixtures can be expressed by the following equation, [a numerical formula] Where, $a_{i}$ and $K_{i}$ represent the weighting factor and the absorption coeffient of i-gray gas respectively; L is the pathlength of the gas. This equation is widely used for the analyses of the radiation heat transfer in the combustors of internal combustion engines and in the furnace of external combustion engines. In this work, a simple calculation model of the weighting factor and the absorption coeffient of the above equation was developed. The weighting factors and the absorption coefficients of combustion products were calculated by applying the model to various kinds of fossil fuels such as coal and heavy oil. Then, the computed total emissivities for each fuel and pathlength were compared with measured and calculated values which have been already published in the literatures. The followings were the results obtained through the comparisons between the calculated emissivites and the published values; the developed model for the calculations of the weighting factor and the absorption coefficient of C $O_{2}$- $H_{2}$O and C $O_{2}$- $H_{2}$O- transient species-soot gas mixtures could be applied over the wide ranges of the temperature and the pathlength; the errors between the total emissivities calculted and the values published were maximum 10%, and average 1%, respectively.