The Modelling of Electrohydraulic Control Valves and its Influence on the Design of Electrohydraulic Drives

1974 ◽  
Vol 16 (3) ◽  
pp. 196-204 ◽  
Author(s):  
A. de Pennington ◽  
J. J. ‘t Mannetje ◽  
R. Bell
Keyword(s):  
Experimental Data ◽  
System Design ◽  
Control Valve ◽  
Feedback Loops ◽  
Model Parameters ◽  
Order Model ◽  
Third Order ◽  
Acceleration Feedback ◽  
Made In

The modelling of the control valve is shown to be a factor of prime importance in the design of electrohydraulic systems. The process required to model a commercially available valve is described in detail, with equal attention to the production of the experimental data and the identification of the model parameters. The quality of the decisions made in the construction of a model is shown to be most critically evaluated when derivative feedback loops are employed. A study of a system with negative transient acceleration feedback is included to illustrate the effectiveness of a third-order model. It is demonstrated that the use of a digital computer is essential for this type of system design.

Arterial pressure contour analysis for estimating human vascular properties

1976 ◽  
Vol 40 (2) ◽  
pp. 171-176 ◽  
Author(s):  
T. B. Watt ◽  
C. S. Burrus
Keyword(s):  
Cardiac Cycle ◽  
Vascular System ◽  
Model Parameters ◽  
Pressure Curve ◽  
Contour Analysis ◽  
Order Model ◽  
Third Order ◽  
Arterial Blood ◽  
Pressure Contour ◽  
Multiple Measurements

The form of an arterial blood pressure curve during the diastolic portion of the cardiac cycle was here employed to identify parameters in a third-order model of the vascular system. Calculated elastic and intertial characteristics of this fitted model then became clinically accessible indices of corresponding real vascular properties. This technique incurred no risk and little discomfort for the patient. Tested in theory, in animal experimentation, and in human observations, our procedure utilized a Gauss-Newton algorithm via digital computer to provide rapid model solutions from different starting values, from multiple measurements sites, and from normal or diseased patients. Model parameters thus determined defined ranges of normal variation and suggested a less compliant arterial bed in hypertensive than in normotensive patients.

scholarly journals The chaos in calibrating crop models

2020 ◽  
Author(s):  
Daniel Wallach ◽  
Taru Palosuo ◽  
Peter Thorburn ◽  
Zvi Hochman ◽  
Emmanuelle Gourdain ◽  
...  
Keyword(s):  
Experimental Data ◽  
Model Calibration ◽  
Crop Model ◽  
Process Models ◽  
Model Parameters ◽  
Model Structure ◽  
Crop Models ◽  
Estimation Of Model Parameters ◽  
Parameter Values ◽  
Made In

Calibration, that is the estimation of model parameters based on fitting the model to experimental data, is among the first steps in essentially every application of crop models and process models in other fields and has an important impact on simulated values. The goal of this study is to develop a comprehensive list of the decisions involved in calibration and to identify the range of choices made in practice, as groundwork for developing guidelines for crop model calibration starting with phenology. Three groups of decisions are identified; the criterion for choosing the parameter values, the choice of parameters to estimate and numerical aspects of parameter estimation. It is found that in practice there is a large diversity of choices for every decision, even among modeling groups using the same model structure. These findings are relevant to process models in other fields.

AN UPDATED TIME-OPTIMAL 3RD-ORDER LINEAR SACCADIC EYE PLANT MODEL

2009 ◽  
Vol 19 (05) ◽  
pp. 309-330 ◽  
Author(s):  
WEI ZHOU ◽  
XINNIAN CHEN ◽  
JOHN ENDERLE
Keyword(s):  
Initial Conditions ◽  
Saccadic Eye Movements ◽  
Physiological Data ◽  
Model Parameters ◽  
Ocular Motor ◽  
Order Model ◽  
Third Order ◽  
Plant Model ◽  
Time Optimal ◽  
Identification Technique

A linear third-order model of the ocular motor plant for horizontal saccadic eye movements is presented consisting of a linear ocular motor plant and a time-optimal saccadic controller based on physiological considerations. The ocular motor plant consists of the eyeball and two extraocular muscles. All parameters and initial conditions are estimated or measured from physiological data. The neural inputs are described by pulse-slide-step waveforms with a post inhibitory rebound burst and based on a time-optimal controller. Model parameters are estimated using the system identification technique. The static and dynamic behaviors of the model are in excellent agreement with the experimental data.

Personalization of Parameters and Validation of Model of the Human Cardiovascular System

2015 ◽  
Vol 10 (2) ◽  
pp. 526-547 ◽  
Author(s):  
И.Н. Киселев ◽  
I.N. Kiselev
Keyword(s):  
Experimental Data ◽  
Pulse Pressure ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Decisive Role ◽  
Model Parameters ◽  
Cardiovascular Model ◽  
Validation Criterion ◽  
Human Cardiovascular System

In the article we present a procedure of human cardiovascular model parameters personalization and its validation against database comprising data of 1546 patients. The algorithm of parameters identification on the basis of experimental data is designed with different parameter combinations. The quality of prediction of the systolic and diastolic pressures is used as the validation criterion. It is shown that with an appropriate personalization the model can provide adequate predictions (correlation near 0.9), where the decisive role is played by the total peripheral resistance parameter. Meanwhile parameters of the largest arteries do not play a significant role in the prediction. At the same time the model with presented personalization technique is not able to provide adequate prediction of pulse pressure.

scholarly journals Damage Detection of Steel-Concrete Composite Beam

2018 ◽  
Vol 28 (3) ◽  
pp. 30-49
Author(s):  
Maciej Szumigała ◽  
Agnieszka Pełka-Sawenko ◽  
Tomasz Wróblewski ◽  
Małgorzata Abramowicz
Keyword(s):  
Experimental Data ◽  
Damage Detection ◽  
Discrete Model ◽  
Composite Beams ◽  
Model Parameters ◽  
Discrete Wavelet ◽  
Identification Procedure ◽  
Original Algorithm ◽  
Automated Optimization ◽  
Made In

Abstract The paper presents analysis results of steel-concrete composite beams, identification and attempts to detect damage introduced in a discrete model. Analysis of damage detection was conducted using DDL (Damage, Detection, Localization), our own original algorithm. Changes of dynamic and static parameters of the model were analysed in damage detection. Discrete wavelet transform was used for damage localization in the model. Prior to ultimate analysis, two-tier identification of discrete model parameters based on experimental data was made. In identification procedure, computational software (Python, Abaqus, Matlab) was connected in automated optimization loops. Results positively verified the original DDL algorithm for damage detection in steel-concrete composite beams, which enables further analysis using experimental data.

scholarly journals Dynamic Modeling of Reversible Methanolysis ofJatropha curcasOil to Biodiesel

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Azhari M. Syam ◽  
Hamidah A. Hamid ◽  
Robiah Yunus ◽  
Umer Rashid
Keyword(s):  
Experimental Data ◽  
Dynamic Modeling ◽  
Catalyst Concentration ◽  
Molar Ratio ◽  
Model Parameters ◽  
Kinetics Study ◽  
Reaction Conditions ◽  
Kinetics Studies ◽  
Optimal Reaction

Many kinetics studies on methanolysis assumed the reactions to be irreversible. The aim of the present work was to study the dynamic modeling of reversible methanolysis ofJatropha curcasoil (JCO) to biodiesel. The experimental data were collected under the optimal reaction conditions: molar ratio of methanol to JCO at 6 : 1, reaction temperature of 60°C, 60 min of reaction time, and 1% w/w of catalyst concentration. The dynamic modeling involved the derivation of differential equations for rates of three stepwise reactions. The simulation study was then performed on the resulting equations using MATLAB. The newly developed reversible models were fitted with various rate constants and compared with the experimental data for fitting purposes. In addition, analysis of variance was done statistically to evaluate the adequacy and quality of model parameters. The kinetics study revealed that the reverse reactions were significantly slower than forward reactions. The activation energies ranged from 6.5 to 44.4 KJ mol−1.

Estimating OLED Display Device Lifetime from pixel and screen brightness and its application

2019 ◽  
Vol 2019 (1) ◽  
pp. 331-338 ◽  
Author(s):  
Jérémie Gerhardt ◽  
Michael E. Miller ◽  
Hyunjin Yoo ◽  
Tara Akhavan
Keyword(s):  
Image Processing ◽  
Power Consumption ◽  
Model Parameters ◽  
Display Device ◽  
Image Processing Algorithm ◽  
Pixel Value ◽  
Device Lifetime ◽  
The Impact ◽  
Oled Display

In this paper we discuss a model to estimate the power consumption and lifetime (LT) of an OLED display based on its pixel value and the brightness setting of the screen (scbr). This model is used to illustrate the effect of OLED aging on display color characteristics. Model parameters are based on power consumption measurement of a given display for a number of pixel and scbr combinations. OLED LT is often given for the most stressful display operating situation, i.e. white image at maximum scbr, but having the ability to predict the LT for other configurations can be meaningful to estimate the impact and quality of new image processing algorithms. After explaining our model we present a use case to illustrate how we use it to evaluate the impact of an image processing algorithm for brightness adaptation.

Орошение томата F1 Донской в открытом грунте Московской области

2019 ◽  
Author(s):  
D.I. Engalychev ◽  
N.A. Engalycheva ◽  
A.M. Menshikh
Keyword(s):  
Experimental Data ◽  
Agricultural Technology ◽  
Tomato Fruits ◽  
River Floodplain ◽  
Yield And Quality ◽  
Open Ground ◽  
Alluvial Meadow ◽  
Standard Production ◽  
Moscow River

Представлены экспериментальные данные о влиянии капельного орошения на урожайность и качество плодов томата при выращивании культуры в открытом грунте Московской области. На плодородных аллювиальных луговых почвах Москворецкой поймы при соблюдении агротехники без орошения в среднем за три года исследований в полевых условиях получена урожайность томата F1 Донской 31,9 т/га, с орошением 48,5 т/га, в т.ч. стандартной продукции 42,6 т/га.The article presents experimental data on the effect of drip irrigation on the yield and quality of tomato fruits when growing crops in open ground of the Moscow Region. On fertile alluvial meadow soils of the Moscow river floodplain, with the observance of agricultural technology without irrigation, the field yield of tomato hybrid F1 Donskoi on average for three years of research was 31.9 t/ha, with irrigation 48.5 t/ha, incl. standard production 42.6 t/ha.

Parameter Determination for Chloride and Tritium Transport in Undisturbed Lysimeters during Steady Flow

1992 ◽  
Vol 23 (2) ◽  
pp. 89-104 ◽  
Author(s):  
Ole H. Jacobsen ◽  
Feike J. Leij ◽  
Martinus Th. van Genuchten
Keyword(s):  
Experimental Data ◽  
Unsaturated Flow ◽  
Transport Model ◽  
Time Moment ◽  
Breakthrough Curves ◽  
Coarse Sand ◽  
Retardation Factor ◽  
Parameter Determination ◽  
Model Parameters ◽  
Water Fraction

Breakthrough curves of Cl and 3H2O were obtained during steady unsaturated flow in five lysimeters containing an undisturbed coarse sand (Orthic Haplohumod). The experimental data were analyzed in terms of the classical two-parameter convection-dispersion equation and a four-parameter two-region type physical nonequilibrium solute transport model. Model parameters were obtained by both curve fitting and time moment analysis. The four-parameter model provided a much better fit to the data for three soil columns, but performed only slightly better for the two remaining columns. The retardation factor for Cl was about 10 % less than for 3H2O, indicating some anion exclusion. For the four-parameter model the average immobile water fraction was 0.14 and the Peclet numbers of the mobile region varied between 50 and 200. Time moments analysis proved to be a useful tool for quantifying the break through curve (BTC) although the moments were found to be sensitive to experimental scattering in the measured data at larger times. Also, fitted parameters described the experimental data better than moment generated parameter values.

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