Various approaches can be used to simulate groundwater flow in karst systems, including equivalent porous media distributed parameter, lumped parameter, and dual porosity approaches, as well as discrete fracture or conduit approaches. The purpose of this study was to evaluate two different equivalent porous media approaches: lumped and distributed parameter, for simulating regional groundwater ...

This contribution describes the development and implementation of a novel software toolbox, NDOT, for the dynamic optimization (open loop optimal control) of nonlinear processes. This modular and flexible toolbox combines the control vector parameterization approach with a number of local and global nonlinear programming solvers and suitable dynamic simulation methods. NDOT is able to solve dyn...

Analysis and design techniques for designing a lumped-element 3-dB quadrature coupler with wide-band flat coupling are proposed for microwave integrated-circuit/monolithic-microwave integrated-circuit applications. The proposed design technique can produce a coupler with flat coupling over 50% fractional bandwidth, which is wider than the conventional lumped-element design methods. A prototype ...

Existing approaches to modeling mismatch effects in matching-critical circuits are based upon models derived under the widely accepted premise that distributed parameter devices can be modeled with lumped parameter models. It is shown in this paper that the lumped parameter models do not consistently reflect device performance and introduce substantial errors in matching-critical circuits if ei...

This paper demonstrates the feasibility of modeling any dynamical system using a set of fractional order differential equations, including distributed and lumped systems. Fractional order differentiators and integrators are the basic elements of these equations representing the real model of the dynamical system, which in turn implies the necessity of using fractional order controllers instead ...

We study the spatially semidiscrete lumped mass method for the model homogeneous heat equation with homogeneous Dirichlet boundary conditions. Improving earlier results we show that known optimal order smooth initial data error estimates for the standard Galerkin method carry over to the lumped mass method whereas nonsmooth initial data estimates require special assumptions on the triangulation...

Abstract Aim of this work is to discuss and verify the ability of a lumped kinetic model of methyl-esters to simulate the oxidation and pyrolysis of mixtures of these components with alcohol fuels. The comparisons between recent experimental data and model predictions further confirm the validity of the kinetic model and the promising perspective of the lumped approach. The results here present...

In this note we study two questions regarding linear time-invariant distributed systems, namely: (1) When can the given system be approximated by a lumped system? (2) When can the given system be stabilized by a lumped system? In each case we obtain a complete answer to the question in terms of the behaviour of the purely atomic parts of the stable numerator and denominator of the plant.