Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 28 for “"DAEs"”.
-
Generalized BDF methods applied to Hessenberg form DAEs
We study the numerical solution of Hessenberg form differential algebraic equations by variable stepsize generalized backward difference formulae (GBDF). GBDF methods of sufficiently high order are shown to converge for problems of index two, three, or four. The proof techniques developed are not …
-
Issues in Interpolatory Model Reduction: Inexact Solves, Second-order Systems and DAEs
… descriptor systems, second-order systems, and DAEs. The main computational cost of interpolatory model reduction is the associated linear systems. Especially in the large-scale setting, inexact solves become desirable if not necessary. With the introduction of inexact solutions, however, exact …
-
Design of a Machine Learning-based classifier for enhancing the accuracy and applicability of DAES, a novel autism screening tool [Sviluppo di un classificatore basato sul Machine Learning per migliorare l'accuratezza e l’applicabilità del DAES, un nuovo strumento di screening per l’autismo]
… osservazionale e interattivo per l’autismo, il DAES (Developmental Autism Early Screening). Abbiamo precedentemente sviluppato questo tool a partire dalla Griffith III (Griffiths Scales of Child Development – Third Edition), con l’obiettivo di intercettare precocemente patterns atipici di …
-
Theory and Application of a Class of Abstract Differential-Algebraic Equations
… for ordinary differential-algebraic equations (DAEs). Because of the geometric and operator-theoretic aspects of this particular method, it can be extended to the case of infinite-dimensional abstract DAEs. For example, partial differential equations (PDEs) are often formulated as abstract …
-
Approximation Methods for the Consistent Initialization of Differential-Algebraic Equations
… in a system of differential-algebraic equations (DAEs) impose a consistency requirement on the initial values that can be difficult to satisfy. In this thesis the consistency requirement is characterized by a system of equations. An approximation method is introduced for these equations, and the …
-
Stability results for constrained dynamical systems
… stability properties of two important classes of DAEs. We consider some special cases of Linear Time Invariant (LTI) DAEs with control inputs and outputs, and also a special class of Linear switched DAEs. In the first part of the thesis, we consider LTI systems, where we focus on two properties: …
-
Reachability analysis and deterministic global optimization of differential-algebraic systems
Systems of differential-algebraic equations (DAEs) are used to model an incredible variety of dynamic phenomena. In the chemical process industry in particular, the numerical simulation of detailed DAE models has become a cornerstone of many core activities including, process development, economic …
-
Applications and numerical investigation of differential-algebraic equations
Differential-algebraic equations (DAEs) result in many areas of science and engineer- ing. In this thesis, numerical methods for solving DAEs are compared for two prob- lems, energy-economic models and traffic flow models. An energy-economic model is presented based on the Hubbert model of oil …
-
Studies on the dynamics of equation-based chemical process flowsheeting systems
… sets of Differential and Algebraic equations (DAEs). The very flexible and effective equation-based (EB) approach in dynamic process flowsheeting calls for the simultaneous solution of the DAE set. However the numerical solution of DAEs is not trivial. The convergence properties of the …
-
Exponential Integrators for the Incompressible Navier-Stokes Equations
… time step. Differential-algebraic equations (DAEs) are ordinary differential equations (ODEs) subject to algebraic constraints. The discretized NSE constitute a system of DAEs, where the incompressibility condition is the algebraic constraint. Exponential integrators can be extended to DAEs …
-
State space modeling of differential-algebraic systems using singularly perturbed sliding manifolds
… and control. One of the key difficulties is that DAEs are not expressed in an explicit state space form required by many simulation and control design methods. This is particularly true in control of nonlinear DAE systems for which there are few known results. Existing control methods for …
-
Waveform relaxation methods for the simulation of systems of differential algebraic equations with applications to electric power systems
… a set of differential/algebraic equations (DAEs). In addition to power systems, systems of differential/algebraic equations arise in connection with singular perturbation, control theory, robot systems, and many other applications in the fields of mechanical and chemical engineering, …
-
Qualitative and Quantitative Investigation of Planar Multibody Dynamics Encompassing GSSSS Family of Algorithms - A Novel In-depth Look
… for the differential-algebraic equations (DAEs) inherent to these systems. The vast majority of these methods require refor- mulation of the natural index 3 equations of motion leading to additional computational cost and the need to control drift phenomena, citing instability of direct …
-
Interlaminar stress analysis of dropped-ply laminated plates and shells by a mixed method
… of both differential and algebraic equations (DAEs) and their associated boundary conditions. Careful evaluation of the system of DAEs was required to arrive at a form that allowed application of a one-step finite difference approximation. A two-stage Gauss implicit Runge-Kutta finite …
-
Transient Stability Analysis of Power Systems with Energy Storage
… simultaneously.(3) Postfault Period: Solve DAEs to determine system response.Simulation results show how energy storage affects CCT and real and reactive power supplied to the load during disturbances such as faults and changes in load.
-
Ecuaciones diferenciales linealmente implícitas. Teoría cualitativa, aspectos computacionales y aplicaciones
… y de ecuaciones algebraico-diferenciales (DAEs). La orientación cualitativa del trabajo motiva la utilización de técnicas celulares o de cell mapping en el estudio computacional global de los sistemas bajo consideración. Dichas técnicas requieren una adecuacióna las características …
-
Numerical Methods for Simulation and Optimization of Chemically Reacting Flows in Catalytic Monoliths
… system of differential-algebraic equations (DAEs). The DAEs are integrated by an implicit method, based on backward differentiation formulas (BDF). We develop a new BDF code with tailored efficient and robust numerical methods by exploiting the structure, and by an appropriate scaling for …
-
Efficient Object-Oriented Modelling, Simulation and Parameter Estimation for Biomechanical Problems
… formalisms and formulated as mechanical DAEs. We use the Generalized Gauß--Newton method based on multiple shooting discretization to estimate the parameters of this dynamic nonlinear parameter estimation problem using measurement data taken from motion capturing. We adapt modelling, …
-
Multiscale Modeling, Reformulation, and Efficient Simulation of Lithium-Ion Batteries
… in a system of differential algebraic equations (DAEs) which must be solved with time as the only differential variable. The system of DAEs can be solved using standard time-adaptive integrating solvers. The error and simulation time of the battery model of orthogonal collocation is …
-
Tools for dynamic model development
… listed above. Differential-algebraic equations (DAEs) can be used to model any ODE system and can also contain algebraic equations, such as those for chemical equilibrium. Software was developed for global dynamic optimization, convergence order was analyzed for the underlying global dynamic …
Page 1 of 2