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A note on transfer function model specification with noisy closed-loop input data

APPLIED STOCHASTIC modelS IN BUSINESS AND INDUSTRY 2010年第4期26卷 473-480页

作者： Ledolter, Johannes Univ Iowa Dept Management Sci Tippie Coll Business Iowa City IA 52242 USA Vienna Univ Econ & Business Vienna Austria

We assume that the input in a transfer function noise model is determined by a proportional-integral-derivative controller that is subject to noise. We show how such a noisy feedback in the input series affects the standard Box-Jenkins method of specifying the transfer function model. Our findings have important implications for the analyst who uses the traditional Box-Jenkins approach. The analyst will be led to estimate an incorrect transfer function model if feedback (exact or noisy) is present. Copyright (C) 2009 John Wiley & Sons, Ltd.

关键词： cross-covariance feedback proportional-integral-derivative control time series modeling transfer function model

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Forecasting models for flow and total dissolved solids in Karoun river-Iran

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JOURNAL OF HYDROLOGY 2016年 535卷 148-159页

作者： Salmani, Mohammad Hassan Jajaei, Efat Salmani Sharif Univ Technol Dept Ind Engn Tehran *** Iran Yazd Univ Dept Pure & Appl Math Yazd 89195741 Iran

Water quality is one of the most important factors contributing to a healthy life. From the water quality management point of view, TDS (total dissolved solids) is the most important factor and many water developing plans have been implemented in recognition of this factor. However, these plans have not been perfect and very successful in overcoming the poor water quality problem, so there are a good volume of related studies in the literature. We study TDS and the water flow of the Karoun river in southwest Iran. We collected the necessary time series data from the Harmaleh station located in the river. We present two Univariate Seasonal Autoregressive Integrated Movement Average (ARIMA) models to forecast TDS and water flow in this river. Then, we build up a transfer function (TF) model to formulate the TDS as a function of water flow volume. A performance comparison between the Seasonal ARIMA and the TF models are presented. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Total dissolved solids Water flow Seasonal ARIMA transfer function model Karoun river

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Control Strategy of VSC-HVDC Inverter Supplying Power to the Isolated Grid with Induction Motor

Control Strategy of VSC-HVDC Inverter Supplying Power to the...

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2017 International Electrical and Energy Conference (CIEEC 2017)

作者： Dalin Chen Yi Hu Xiaoru Wang Feng Shen Yufei Teng School of Electrical Engineering Southwest Jiaotong University State Grid Sichuan Electrical Power Research Institute

High voltage direct current transmission system based on voltage source converter(VSC-HVDC) can supply power to the weak AC network or the passive *** the only generator in an isolated grid is out of operation,the isolated grid supplied by VSC-HVDC will become the passive network and the research about how to control the inverter of VSC to ensure safety and stability of the isolated grid during the fault has great *** this paper,the transfer function model of passive network is built with considering the inertia of the induction *** additional frequency control strategy for VSC-HVDC inverter is proposed in the *** performance of VSCHVDC system supplying power to the active AC network and the passive network with the additional control strategy is simulated in PSCAD/*** simulation results verify the correctness of transfer function model and the effectiveness of the proposed control strategy.

关键词： Additional frequency control Induction motor Passive grid transfer function model VSC-HVDC

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Estimating travel time of recharge water through a deep vadose zone using a transfer function model

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ENVIRONMENTAL FLUID MECHANICS 2010年第1-2期10卷 121-135页

作者： Mattern, Samuel Vanclooster, Marnik Univ Catholique Louvain B-1348 Louvain Belgium

We estimate the travel time of percolating water through a deep vadose zone at the regional scale using a transfer function model and a physical based conceptual flow model (Hydrus-1D), thereby exploiting the time series of precipitation, actual evapotranspiration and groundwater piezometry and generic vadose zone data. With the transfer function model we observe a high variability of estimated travel time varying from 0.9 to 3.1 years, corresponding to estimated vertical water flux velocities varying from 6.6 to 28.0 m/year. These results were compared with the travel time estimated from the physical based conceptual model. With the flow model, estimated travel time varies between 4.7 and 15.5 years, corresponding to water flux velocities varying between 1.7 and 4.1 m/year. The estimated travel time calculated with the flow model were therefore about five times larger than those estimated with the transfer function model. This could be explained by the fact that the transfer function model considers heterogeneous recharge from the vadose zone as well as from the vicinity of the piezometer through the so called "pushing effect". In addition, the flow model requires various hydrogeological and hydrodynamic parameters which were estimated using generic parametrisation approaches, that are largely affected by uncertainty and may not reflect the local conditions. In contrast, the transfer function model only exploits available measurable time series and has the advantage of being site-specific.

关键词： transfer function model Travel time Soil Groundwater level fluctuations Brusselian sands

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Control Oriented modeling of a De-oiling Hydrocyclone

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IFAC-PapersOnLine 2015年第28期48卷 291-296页

作者： Durdevic, Petar Pedersen, Simon Bram, Mads Hansen, Dennis Hassan, Abdiladif Yang, Zhenyu Aalborg University 6700 Denmark

Deoiling hydrocyclones are an important part of the downstream water treatment in offshore oil & gas production, they ensure a low discharge of oil and thus a higher yield of produced oil. This work investigates the possibility of developing a simple control-oriented model of a de-oiling hydrocyclone based on experimental data that can support systematic analysis and control design of hydrocyclone systems. The most widely used control solution of a hydrocyclone is a Pressure Drop Ratio (PDR) control strategy, which is often empirically designed and experimentally tuned in a case-by-case manner. There is a lack of a systematic and deep-insight analysis of the capability, stability and limitations of these control solutions, as there are few control-oriented models available for de-oiling hydrocyclone systems. This paper proposes a method of retrieving a set of simple 1st-order transfer function models from a set of designed experiments based on a lab-scaled hydrocyclone system. Some preliminary results are also illustrated and discussed. The conclusion of this preliminary study is that the models obtained can emulate the dynamics of the system in a reasonable manner subject to the trade-off between simplicity and accuracy. In addition, higher order state space models are introduced and their relative advantage of depicting the complicated dynamics of the hydrocyclone's pressures is investigated. © 2015

关键词： Cyclone separators Economic and social effects Offshore oil well production State space methods Water treatment Control oriented models Control strategies Designed experiments Hydrocyclones Multi model Pressure drop ratio Systematic analysis transfer function model

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Automated Design of Digital Systems with Parallel Architecture

Automated Design of Digital Systems with Parallel Architectu...

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Proceedings of the IEEE North West Russia Section Young Researchers in Electrical and Electronic Engineering Conference (2015 ElConRusNW)

作者： Andreev, V. S. Butusov, D. N. Karimov, A. I. Karimov, T. I. St Petersburg State Electrotech Univ LETI St Petersburg Russia

ISBN: (纸本)9781479973064

The article discusses the modification of a digital signal processing systems design method, based on the parallel decomposition of dynamical systems, which can be described by a transfer function. This method is suitable for the development of digital control and signal processing systems with higher precision and lower delay characteristics by parallelizing the computation process. The program algorithms that allow the automatic conversion of the dynamical system models in the form of a transfer function or zero-pole-gain model to the sum of first and second order transfer functions are represented. A validation of the described method is made by creating and simulating dynamical system model in NI LabVIEW development system. Analysis of the efficiency and accuracy of the derived solution in the time domain is performed. It is shown that the proposed implementation of a dynamical system model can replace the classical approaches to implementation, and is suitable for solving the current problems of digital signal processing.

关键词： dynamical systems simulation transfer function model zero-pole-gain model computer-aided design parallel computing high-performance systems

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Accurate Material Parameter Extraction from Broadband Terahertz Spectroscopy 40

Accurate Material Parameter Extraction from Broadband Terahe...

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40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

作者： Greenall, N. R. Wood, C. D. Russell, C. Li, L. H. Linfield, E. H. Davies, A. G. Cunningham, J. E. Burnett, A. D. Univ Leeds Sch Elect & Elect Engn Leeds LS2 9JT W Yorkshire England Univ Leeds Sch Chem Leeds LS2 9JT W Yorkshire England

ISBN: (纸本)9781479982721

We demonstrate how a transfer function model based parameter extraction method, combined with total variance analysis, allows the extraction of both the complex refractive index and the thickness of a sample over a bandwidth of >6 THz from THz time-domain spectroscopy measurements. We discuss how the techniques developed have been applied to absorbent powders measured at variable low temperatures.

关键词： parameter estimation refractive index measurement terahertz spectroscopy transfer function matrices broadband terahertz spectroscopy complex refractive index parameter extraction method terahertz time-domain spectroscopy total variance analysis transfer function model Bandwidth Refractive index Silicon Spectroscopy Temperature measurement Thickness measurement Time-domain analysis

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Forecast Performance of the Taiwan Weighted Stock Index

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REVIEW OF PACIFIC BASIN FINANCIAL MARKETS AND POLICIES 2015年第3期18卷 1550017-1550017页

作者： Ji, Deng-Yuan Lee, Cheng-Few Chen, Hsiao-Yin Kainan Univ Dept Mkt Taoyuan Taiwan Rutgers State Univ Finance & Econ New Brunswick NJ USA Kainan Univ Dept Business & Entrepreneurial Management Taoyuan Taiwan

This research introduces the following to establish a Taiwan Weighted stock index (TAIEX) prediction model: intervention analysis integrated into the ARIMAGARCH model, error correction model (ECM), intervention analysis integrated into the transfer function model, the simple average combination forecasting model, and the minimum error combination forecasting model. The results show that intervention analysis integrated into the transfer function model yields a more accurate prediction model than ECM and intervention analysis integrated into the ARIMA-GARCH model. The minimum error combination forecasting model can improve prediction accuracy much better than non-combination models and also maintain robustness. Intervention analysis integrated into the transfer function model shows that the TAIEX is affected by external factors, the INDU, the exchange rate, and the consumer price index;therefore, facing the different issues of the TAIEX, the government could pursue some macroeconomic policies to reach the goals of policies.

关键词： transfer function model intervention combination forecasting model

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model-based vs Auto-tuning Design of PID Controller for Knee Flexion During Gait

Model-based vs Auto-tuning Design of PID Controller for Knee...

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IEEE International Conference on Systems, Man, and Cybernetics (SMC)

作者： Chevalier, A. Ionescu, C. M. De Keyser, R. Univ Ghent Dept Elect Energy Syst & Automat Technol Pk 913 B-9052 Ghent Belgium

ISBN: (纸本)9781479938407

This paper discusses the derivation of a theoretical model of the movement of the shank, i.e. the lower part of the leg, around the knee joint. The objective is to control the angle of the shank with respect to the position of the upper leg. Subsequently, two types of design techniques are used to design a PID controller for the derived system: a model-based design method and an auto-tuner technique. The resulting PID controllers are compared by simulating a squat movement and a normal gait. We conclude that both PID controllers perform similar but the control effort for the auto-tuner technique presents a smoother course. However, the main advantage of the PID auto-tuner technique is that no mathematical transfer function model is necessary in order to tune the controller.

关键词： control system synthesis medical control systems patient treatment three-term control transfer functions PID controller design auto-tuning design knee flexion model-based design normal gait proportional-integral-derivative controller shank angle control shank movement squat movement transfer function model Biological system modeling Biomechanics Joints Knee Mathematical model Torque transfer functions

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Hydrological behaviour of a drained agricultural peat catchment in the tropics. 2: Time series transfer function modelling approach

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Hydrological Sciences Journal 2013年第6期58卷 1310页

作者： Katimon, Ayob Shahid, Shamsuddin Abd Wahab, Ahmad Khairi Shabri, Ani [a] Department of Hydraulics and Hydrology Faculty of Civil Engineering Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia [b] Department of Mathematics Faculty of Science Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia

transfer function models of the rainfall-runoff relationship with various complexities are developed to investigate the hydrological behaviour of a tropical peat catchment that has undergone continuous drainage for a long time. The study reveals that a linear transfer function model of order one and noise term of ARIMA (1,0,0) best represents the monthly rainfall-runoff relationship of a drained peat catchment. The best-fitted transfer function model is capable of illustrating the cumulative hydrological effects of the catchment when subjected to drainage. transfer function models of daily rainfall-runoff relationships for each year of the period 1983-1993 are also developed to decipher the changes in hydrological behaviour of the catchment due to drainage. The results show that the amount of rain water temporarily stored in the peat soil decreased and the catchment has become more responsive to rainfall over the study period. Editor Z.W. Kundzewicz; Associate editor D. Hughes Citation Katimon, A., Shahid, S., Abd Wahab, A.K., and Shabri, A., 2013. Hydrological behaviour of a drained agricultural peat catchment in the tropics. 2: Time series transfer function modelling approach. Hydrological Sciences Journal, 58 (6), 1310-1325.

关键词： drained peat catchment rainfall–runoff transfer function model ARIMA bassin versant drainé en zone de tourbière pluie–débit modèle de fonction de transfert ARIMA

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