scholarly journals Fundamental Investigations on Identifying Generator Model Parameter Values by Utilizing the Synchronization of the Chaotic Behavior

2001 ◽  
Vol 121 (12) ◽  
pp. 1833-1839
Author(s):  
Toshihiro KITA
Robotica ◽  
2005 ◽  
Vol 23 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Katja D. Mombaur ◽  
Richard W. Longman ◽  
Hans Georg Bock ◽  
Johannes P. Schlöder

We present simulated monopedal and bipedal robots that are capable of open-loop stable periodic running motions without any feedback even though they have no statically stable standing positions. Running as opposed to walking involves flight phases which makes stability a particularly difficult issue. The concept of open-loop stability implies that the actuators receive purely periodic torque or force inputs that are never altered by any feedback in order to prevent the robot from falling. The design of these robots and the choice of model parameter values leading to stable motions is a difficult task that has been accomplished using newly developed stability optimization methods.


2013 ◽  
Vol 49 (10) ◽  
pp. 6700-6715 ◽  
Author(s):  
José-Luis Guerrero ◽  
Ida K. Westerberg ◽  
Sven Halldin ◽  
Lars-Christer Lundin ◽  
Chong-Yu Xu

2011 ◽  
Vol 24 (5) ◽  
pp. 1480-1498 ◽  
Author(s):  
Andrew H. MacDougall ◽  
Gwenn E. Flowers

Abstract Modeling melt from glaciers is crucial to assessing regional hydrology and eustatic sea level rise. The transferability of such models in space and time has been widely assumed but rarely tested. To investigate melt model transferability, a distributed energy-balance melt model (DEBM) is applied to two small glaciers of opposing aspects that are 10 km apart in the Donjek Range of the St. Elias Mountains, Yukon Territory, Canada. An analysis is conducted in four stages to assess the transferability of the DEBM in space and time: 1) locally derived model parameter values and meteorological forcing variables are used to assess model skill; 2) model parameter values are transferred between glacier sites and between years of study; 3) measured meteorological forcing variables are transferred between glaciers using locally derived parameter values; 4) both model parameter values and measured meteorological forcing variables are transferred from one glacier site to the other, treating the second glacier site as an extension of the first. The model parameters are transferable in time to within a <10% uncertainty in the calculated surface ablation over most or all of a melt season. Transferring model parameters or meteorological forcing variables in space creates large errors in modeled ablation. If select quantities (ice albedo, initial snow depth, and summer snowfall) are retained at their locally measured values, model transferability can be improved to achieve ≤15% uncertainty in the calculated surface ablation.


2015 ◽  
Vol 15 (02) ◽  
pp. 1540014 ◽  
Author(s):  
ANDREA DUGGENTO ◽  
NICOLA TOSCHI ◽  
ANTONIO CANICHELLA ◽  
ITALO VANNUCCI ◽  
MARIA GUERRISI

We investigate the Seidel–Herzel model of the human baroreflex feedback control mechanism in terms of parameter choices and its ability to mimic heart rate physiology. We show that this model has the potential to be re-parameterized to better mimic features commonly observed in human physiology. We investigate the modification of the RR return maps as a function of parameter values and show that the model exhibits chaotic behavior. Extensive simulations are performed to establish which parameters mostly contribute to model flexibility in terms of observable output, and critical considerations are cast about potential pitfalls in model re-parameterization to mimic health and pathological behaviors. The Seidel–Herzel model is then merged with a detailed 21-compartment model for the vascular bed in order to examine sensitivity of RR dynamics to whole body simulation parameters. Pathological situations are simulated by altering total blood volume, ventricular compliances and baroreflex gains. The RR solutions show bifurcation diagrams typical of chaotic behavior, where the extension of the chaotic regions is in general smaller in simulated pathological states when compared to baseline (healthy) situations. We speculate that, despite the limits of the model and the limitations of the physiological parameterization, a loss of chaotic behavior correlates with the presence of disease-related aberrations.


In this work titled Stability, Bifurcation, Chaos: Discrete prey predator model with step size, by Forward Euler Scheme method the discrete form is obtained. Equilibrium states are calculated and the stability of the equilibrium states and dynamical nature of the model are examined in the closed first quadrant 2 R with the help of variation matrix. It is observed that the system is sensitive to the initial conditions and also to parameter values. The dynamical nature of the model is investigated with the assistance of Lyapunov Exponent, bifurcation diagrams, phase portraits and chaotic behavior of the system is identified. Numerical simulations validate the theoretical observations.


Total hip metal arthroplasty (THA) model-parameters for a group of commonly used ones is optimized and numerically studied. Based on previous ceramic THA optimization software contributions, an improved multiobjective programming method/algorithm is implemented in wear modeling for THA. This computational nonlinear multifunctional optimization is performed with a number of THA metals with different hardnesses and erosion in vitro experimental rates. The new software was created/designed with two types of Sytems, Matlab and GNU Octave. Numerical results show be improved/acceptable for in vitro simulations. These findings are verified with 2D Graphical Optimization and 3D Interior Optimization methods, giving low residual-norms. The solutions for the model match mostly the literature in vitro standards for experimental simulations. Numerical figures for multifunctional optimization give acceptable model-parameter values with low residual-norms. Useful mathematical consequences/calculations are obtained for wear predictions, model advancements and simulation methodology. The wear magnitude for in vitro determinations with these model parameter data constitutes the advance of the method. In consequence, the erosion prediction for laboratory experimental testing in THA add up to the literature an efficacious usage-improvement. Results, additionally, are extrapolated to efficient Medical Physics applications and metal-THA Bioengineering designs.


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