• Title/Summary/Keyword: Model mismatch

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Linear Input/output Data-based Predictive Control with Integral Property

  • Song, In-Hyoup;Yoo, Kee-Youn;Park, Myung-Jung;Rhee, Hyun-Ku
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.101.5-101
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    • 2001
  • A linear input/output data-based predictive control with integral action is developed. The control input is obtained directly from the input/output data in a single step. However, the state estimation in subspace identification gives a biased estimate and there is model mismatch when the controller is applied to a nonlinear process. To overcome such difficulties, we add integral action to a linear input/output data-based predictive controller by augmenting the integrated white noise disturbance model and use each of best linear unbiased estimation(BLUE) filter and Kalman filter as a stochastic observer for the unmeasured disturbance. When applied to a continuous styrene polymerization reactor the proposed controller demonstrates.

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A Simple Real-Time DMPPT Algorithm for PV Systems Operating under Mismatch Conditions

  • Aniruddha, Kamath M.;Jayanta, Biswas;Anjana, K.G.;Mukti, Barai
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.826-840
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    • 2018
  • This paper presents a distributed maximum power point tracking (DMPPT) algorithm based on the reference voltage perturbation (RVP) method for the PV modules of a series PV string. The proposed RVP-DMPPT algorithm is developed to accurately track the maximum power point (MPP) for each PV module operating under all atmospheric conditions with a reduced hardware overhead. To study the influence of parameters such as the controller reference voltage ($V_{ref}$) and PV current ($I_{pv}$) on the PV string voltage, a small signal model of a unidirectional differential power processing (DPP) based PV-Bus architecture is developed. The steady state and dynamic performances of the proposed RVP DMPPT algorithm and small signal model of the unidirectional DPP based PV-Bus architecture are demonstrated with simulations and experimental results. The accuracy of the RVP DMPPT algorithm is demonstrated by obtaining a tracking efficiency of 99.4% from the experiment.

Nonlinear Analysis of End-to-End Anastomosis Using Sub-modeling (Sub-modeling을 이용한 end-to-end 문합의 비선형 해석)

  • 한근조;안성찬;심재준
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.2
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    • pp.192-198
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    • 2003
  • A finite element analysis of end-to-end artery/PTFE anastomosis has been presented in this study to evaluate the distribution of compliance and stresses in the vicinity of the anastomosis due to any mismatch in compliance characteristics. The artery wall was assumed to be made of linear isotropic material in this simplified model and a nonlinear analysis and convergency study with respect to increasing meshed element numbers were performed with a mean artery pressure loading of the artery-PTFE model. Also, sub-modeling method was Introduced to progress the accuracy of the finite element analysis. The results are as follow : 1. A hypercompliant zone on the artery side was observed around 4.Omm from the anastomosis and a high hoop stresses in the wall of artery and PTFE was dominant. 2. An artery displays large deformation so that nonlinear analysis and sub-modeling method was used. 3. An anastomosis with the thinner thickness and larger diameter PTFE (B type) could reduce the compliance disagreement.

Strength Analysis of Particle-Reinforced Composites with Length-Scale Effect based on Geometrically Necessary Dislocations (기하적 필수 전위에 의한 길이효과를 고려한 입자 강화 복합재의 강도해석)

  • Suh, Y.S.;Joshi, Shailendra P.;Ramesh, K.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.322-325
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    • 2009
  • An enhanced continuum model for the size dependent strengthening of particle reinforced composites is presented. The model accounts explicitly for the enhanced strength in a discretely defined "punched zone" around the particle in a metal matrix composite as a result of geometrically necessary dislocations developed through a CTE mismatch. The size of the punched zone presents an intrinsic length scale, and this results in the size dependence of the overall behavior of the composite. Results show that predicted 0.2% offset yield stresses are increasing with smaller inclusions and larger volume fractions and this length-scale effect on the enhanced strength can be observed by explicitly including GND region around the particle.

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Local Structure Invariant Potential for InxGa1-xAs Semiconductor Alloys

  • Sim, Eun-Ji;Han, Min-Woo;Beckers, Joost;De Leeuw, Simon
    • Bulletin of the Korean Chemical Society
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    • v.30 no.4
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    • pp.857-862
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    • 2009
  • We model lattice-mismatched group III-V semiconductor $In_{x}Ga_{1-x}$ alloys with the three-parameter anharmonic Kirkwood-Keating potential, which includes realistic distortion effect by introducing anharmonicity. Although the potential parameters were determined based on optical properties of the binary parent alloys InAs and GaAs, simulated dielectric functions, reflectance, and Raman spectra of alloys agree excellently with experimental data for any arbitrary atomic composition. For a wide range of atomic composition, InAs- and GaAs-bond retain their respective properties of binary parent crystals despite lattice and charge mismatch. It implies that use of the anharmonic Kirkwood-Keating potential may provide an optimal model system to investigate diverse and unique optical properties of quantum dot heterostructures by circumventing potential parameter searches for particular local structures.

A Fault Detection Method for Uncertain Continuous and Discrete-Time Systems (불확실한 연속형 및 이산형 시스템에서의 이상검출법)

  • Hwang, In-Koo;Kwon, Oh-Kyu
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.10
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    • pp.60-67
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    • 1990
  • This paper proposes a model-based fault detection method for linear/nonlinear system having modelling errors, nonlinearities and measurement noise. The system model is represented by the unified operator [5] in order to apply to both the continuous-time and discrete-time problems. The fault detection method suggested here accounts for the effects of noise, model mismatch and nonlinearities. Modelling errors are depicted by additive forms and the nominal model denominator is fixed via prior experiments in order to quantify the nucertainty bound on the parameter estima-tion. The least square method is used to estimate the numerator parameters of the nominal model. performance than traditional methods.

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Applying feature normalization based on pole filtering to short-utterance speech recognition using deep neural network (심층신경망을 이용한 짧은 발화 음성인식에서 극점 필터링 기반의 특징 정규화 적용)

  • Han, Jaemin;Kim, Min Sik;Kim, Hyung Soon
    • The Journal of the Acoustical Society of Korea
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    • v.39 no.1
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    • pp.64-68
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    • 2020
  • In a conventional speech recognition system using Gaussian Mixture Model-Hidden Markov Model (GMM-HMM), the cepstral feature normalization method based on pole filtering was effective in improving the performance of recognition of short utterances in noisy environments. In this paper, the usefulness of this method for the state-of-the-art speech recognition system using Deep Neural Network (DNN) is examined. Experimental results on AURORA 2 DB show that the cepstral mean and variance normalization based on pole filtering improves the recognition performance of very short utterances compared to that without pole filtering, especially when there is a large mismatch between the training and test conditions.

SPICE Modeling for Thermoelectric Modules (열전 모듈의 SPICE 모델링)

  • Park, Soon-Seo;Cho, Sung-Kyu;Baatar, Nyambayar;Kim, Shi-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.4
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    • pp.7-12
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    • 2010
  • We have developed a SPICE compatible model of thermoelectric devices, and a parameter extracting technique only by electrical and temperature measurement by using Harman method was proposed. The proposed model and parameter extraction technique do not require experimental data from thermal conductivity measurements. The maximum error between extracted parameters extracted by proposed method and conventional method was about 14%, which is not a severe mismatch for real application. The proposed model is applicable to design of both for thermoelectric coolers and thermo electric generators.

Current Control of a Three-Phase PWM converter Based on a New control Model with a Time Delay and SVPWM Effects (시지연과 SVPWM 영향이 고려된 새로운 제어 모델에 의한 3상 전압원 PWM 컨버터의 전류 제어)

  • 민동기;안성찬;현동석
    • The Transactions of the Korean Institute of Power Electronics
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    • v.5 no.2
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    • pp.115-122
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    • 2000
  • In design of a digital current controller for a 3cP PWM converter, its conventional model is used in obtaining i its discretized version. But, it has errors since the characteristics of SVPWM and time delay are not taken i into consideration. In this paper, the new reference frame model of a 3c~ PWJVI converter is proposed C considering these problems. Also, the direct digital current controller based on this model is designed without a any extra algolithm. A simple tuning algorithm for the proposed current controller is given to compensate the i inductaηce mismatch problem. Then simulation and experimental results show the validity of the algolithm.

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Creep Characterization of Type 316LN and HT-9 Stainless Steels by the K-R Creep Damage Model

  • Kim, U-Gon;Kim, Seong-Ho;Ryu, U-Seok
    • Journal of Mechanical Science and Technology
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    • v.15 no.11
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    • pp.1463-1471
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    • 2001
  • The Kachanov and Rabotnov (K-R) creep damage model was interpreted and applied to type 316LN and HT-9 stainless steels. Seven creep constants of the model, A, B, $textsc{k}$, m, λ, ${\gamma}$, and q were determine d for type 316LN stainless steel. In order to quantify a damage parameter, the cavity was interruptedly traced during creep for measuring cavity area to be reflected into the damage equation. For type 316LN stainless steel, λ= $\varepsilon$R/$\varepsilon$* and λf=$\varepsilon$/$\varepsilon$R were 3.1 and increased with creep strain. The creep curve with λ=3.1 depleted well the experimental data to the full lifetime and its damage curve showed a good agreement when r=24. However for the HT-9 stainless steel, the values of λ and λf were different as λ=6.2 and λf=8.5, and their K-R creep curves did not agree with the experimental data. This mismatch in the HT-9 steel was due to the ductile fracture by softening of materials rather than the brittle fracture by cavity growth. The differences of the values in the above steels were attributed to creep ductilities at the secondary and the tertiary creep stages.

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