• Title/Summary/Keyword: State space model

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Identification of Linear Model of Tandem Cold Mill Using N4SID Algorithm (N4SID 알고리즘을 이용한 연속 냉간 압연기의 선형모델 규명)

  • 엄상오;황이철;김윤식;김종윤;박영산
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.3 no.4
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    • pp.895-905
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    • 1999
  • This paper identifies a linear time-invariant mathematical model of each stand of a five-stand tandem cold mill to design a robust $H_\infty$ thickness controller by applying input and output data sets to N4SID (Numerical algorithms for Subspace State Space System Identification) method. The input-output data sets describe interstand interference in the process of tandem cold rolling and are obtained from a nonlinear simulator of the tandem cold mill. In result, it is shown that the identified model well approximates the nonlinear model than a Taylor linearized model. Furthermore, uncertainties including roll eccentricity and incoming strip variation are quantitatively analyzed from the plot of maximum singular values.

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Shape model and spin state of non-principal axis rotator (5247) Krylov

  • Lee, Hee-Jae;Durech, Josef;Kim, Myung-Jin;Moon, Hong-Kyu;Kim, Chun-Hwey
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.45.2-45.2
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    • 2019
  • The main-belt asteroid (5247) Krylov is known as a Non-Principal Axis (NPA) rotator. However, the shape model and spin state of this asteroid were not revealed. The physical model of an asteroid including spin state and shape is regarded to be important to understand its physical properties and dynamical evolution. Thus, in order to reconstruct the physical model of Kryolv, we applied the light curve inversion method using not only the optical light curves observed with ground-based telescopes in three apparitions during 2006, 2016, and 2017, but also the infrared light curves obtained with the Wide-field Infrared Survey Explorer (WISE) in 2010. We found that it is rotating in Short Axis Mode (SAM) with the rotation and precession periods of 368.71 hr and 67.277 hr, respectively. The orientation of the angular momentum vector is (298°, -58°) in the ecliptic coordinate system. The ratio of moments of inertia of the longest axis to the shortest axis is Ia/Ic = 0.36; the ratio of moments of inertia of the intermediate axis to the shortest axis is Ib/Ic = 0.96. Finally, the excitation level of this asteroid is found to be rather low with a ratio of the rotational kinetic energy to the basic spin state energy as E/E0 ≃ 1.024. We will briefly discuss the possible evolutionary process of Krylov in this presentation.

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Analysis of Switching Transient State characteristis Based on Space charge Overlapping Model (공간전하중첩 모델에 의한 스위칭과도장태 특성해석)

  • 정홍배;박창엽
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.18 no.2
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    • pp.27-35
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    • 1981
  • In this study, a numerical theory based on space charge overlapping model and experiments on the propriety of its theory were carried out to analyze the switching transient characteristic in amorphous coalcogenide thin film. Theoretical and experimental as well as analytical investigations were carried out on the switching behaviour in a transient state arising from a voltage pulse applied to amorphous chalcogenide thin films at room temperature. The results can be explained in terms ot a simple theoretical model of the electronic characteristics of switching. The injection of carriers are necessary to initiate the switching action and injected carriers contribute to the current flow as a space-charge limited current(SCLC) The proposed charge controlled switching characteristics can be explained by double injection space charge overlapping model.

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A Bayesian State-space Production Assessment Model for Common Squid Todarodes pacificus Stock Caught by Multiple Fisheries in Korean Waters (한국 해역의 살오징어(Todarodes pacificus) 개체군 자원평가를 위한 베이지안 상태공간 잉여생산량 모델의 적용)

  • An, Dongyoung;Kim, Kyuhan;Kang, Heejung;Hyun, Saang-Yoon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.5
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    • pp.769-781
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    • 2021
  • Given data about the annual fishery yield of the common squid Todarodes pacificus, and the catch-per-unit-effort (CPUE) data from multiple fisheries from 2000-2018, we applied a Bayesian state - space assessment model for the squid population. One of our objectives was to do a stock assessment, simultaneously incorporating CPUE data from the following three fisheries, (i) large trawl, (ii) jigger, and (iii) large purse seine, which comprised on average a year about 65% of all fisheries, allowing possible correlations to be reflected. Other objectives were to consider both observation and process errors and to apply objective priors of parameters. The estimated annual exploitable biomass was in the range of 3.50×105 to 1.22×106 MT, the estimated intrinsic growth rate was 1.02, and the estimated carrying capacity was 1,151,259 MT. Comparison with available results from stock assessment of independently analyzed single fisheries revealed a large difference from the estimated values, suggesting that stock assessment based on multiple fisheries should be performed.

A Balanced Model Reduction for Linear Parameter Varying Systems (시변 파라메터를 갖는 선형시스템의 균형화된 모델 간략화)

  • Yoo, Seog-Hwan
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.5
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    • pp.351-356
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    • 2002
  • This papaer deals with a model reduction problem for linear systems with time varying parameters. For this problem, a controllability Grammian and an observability Grammian are introduced and computed by solving linear matrix inequalities. Using the controllability/observability Grammian, a balanced state space realization for linear parameter varying systems is obtained. From the balanced state space realization, a reduced model can be obtained by truncating not only states but also time varying parameters and an upper bound of the model reduction error is derived as well.

Reduced Order Luenberger State Observer Design for the Jackknifing Phenomenon Prevention of Articulated Vehicles using GPS (위성항법시스템을 이용한 연결식 차량의 잭나이핑 현상 예방을 위한 축소차수 상태관측기 설계)

  • Lee, Byung-Seok;Heo, Moon-Beom
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.7
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    • pp.688-698
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    • 2012
  • This paper deals with ROLSO (Reduced Order Luenberger State Observer) design to prevent jackknifing phenomenon of articulated vehicles consisting of the tractor and semi-trailer by using GPS. In addition, by applying the regulator system using ROLSO feedback system, simulation's result presents that articulated vehicle's states are stabilized than the human's PR time (Preception Response time) rapidly. This simulation verifies that the automatic control of articulated vehicle's can be applied for the accident prevention for the time that the driver is unable to manage with the sudden accident. For this simulation, by using the equation of planar motion, the modeling of the articulated vehicle was performed. This modeling was expressed in the state space model. And FOLSO (Full Order Luenberger State Observer), ROLSO were designed by using the state space model of an articulated vehicle's dynamics.

A Sequential Monte Carlo inference for longitudinal data with luespotted mud hopper data (짱뚱어 자료로 살펴본 장기 시계열 자료의 순차적 몬테 칼로 추론)

  • Choi, Il-Su
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.6
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    • pp.1341-1345
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    • 2005
  • Sequential Monte Carlo techniques are a set of powerful and versatile simulation-based methods to perform optimal state estimation in nonlinear non-Gaussian state-space models. We can use Monte Carlo particle filters adaptively, i.e. so that they simultaneously estimate the parameters and the signal. However, Sequential Monte Carlo techniques require the use of special panicle filtering techniques which suffer from several drawbacks. We consider here an alternative approach combining particle filtering and Sequential Hybrid Monte Carlo. We give some examples of applications in fisheries(luespotted mud hopper data).

Colour Linear Array Image Enhancement Method with Constant Colour

  • Ji, Jing;Fang, Suping;Cheng, Zhiqiang
    • Current Optics and Photonics
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    • v.6 no.3
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    • pp.304-312
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    • 2022
  • Digital images of cultural relics captured using line scan cameras present limitations due to uneven intensity and low contrast. To address this issue, this report proposes a colour linear array image enhancement method that can maintain a constant colour. First, the colour linear array image is converted from the red-green-blue (RGB) colour space into the hue-saturation-intensity colour space, and the three components of hue, saturation, and intensity are separated. Subsequently, the hue and saturation components are held constant while the intensity component is processed using the established intensity compensation model to eliminate the uneven intensity of the image. On this basis, the contrast of the intensity component is enhanced using an improved local contrast enhancement method. Finally, the processed image is converted into the RGB colour space. The experimental results indicate that the proposed method can significantly improve the visual effect of colour linear array images. Moreover, the objective quality evaluation parameters are improved compared to those determined using existing methods.

Constrained multivariable model based predictive control application to nonlinear boiler system (제약조건을 갖는 다변수 모델 예측 제어기의 비선형 보일러 시스템에 대한 적용)

  • 손원기;이명의;권오규
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.160-163
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    • 1996
  • This paper deals with MCMBPC(Multivariable Constrained Model Based Predictive Controller) for nonlinear boiler system with noise and disturbance. MCMBPC is designed by linear state space model obtained from some operating point of nonlinear boiler system and Kalman filter is used to estimate the state with noise and disturbance. The solution of optimization of the cost function constrained on input and/or output variables is achieved using quadratic programming, viz. singular value decomposition (SVD). The controller designed is shown to have excellent tracking performance via simulation applied to nonlinear dynamic drum boiler turbine model for 16OMW unit.

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The Contribution of Innovation on Productivity and Growth in Korea (기술혁신이 생산성과 경제성장에 미치는 영향)

  • Kim, Byung-Woo
    • Journal of Korea Technology Innovation Society
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    • v.11 no.1
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    • pp.72-90
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    • 2008
  • What has been the contribution of industrial innovation to economic growth? Typically, the issue has been approached with growth-accounting methods augmented to include a "stock of knowledge". An independent estimate of the rate of return to R&D is found in order to impute patents granted to the accumulation of knowledge. Griliches(1973) then uses a regression approach to assess the effect of an R&D variable on the computed TFP growth rate. The regression coefficient on the R&D variable would provide an estimate of the social rate of return to R&D. The related studies tend to show high social rates of return to R&D, typically in a range of 20 to 40 % per year. We need to provide multiple equation dynamic system for productivity and innovation in Korean economy in state space form. A wide range of time series models, including the classical linear regression model, can be written and estimated as special cases of a state space specification. State space models have been applied in the econometrics literature to model unobserved variables like productivity. Estimation produces the following results. Considering the goodness of fit, we can see that the evidence is strongly in favor of the range $0.120{\sim}0.135$ for the elasticity of TFP to R&D stock in the period between 1970's and the early 2000's.

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