Functional inversion based on local approximate solutions (LAS) is developed for steady-state flow in heterogeneous aquifers. The method employs a set of LAS of flow to impose spatial continuity of hydraulic head and Darcy fluxes in the solution domain, which are conditioned to limited measurements. Hydraulic conductivity is first parameterized as piecewise continuous, which requires the additi...

A finite element method to approximate the vibration modes of a structure enclosing an acoustic fluid is analyzed. The fluid is described by using simultaneously pressure and displacement potential variables, whereas displacement variables are used for the solid. A mathematical analysis of the continuous spectral problem is given. The problem is discretized on a simplicial mesh by using piecewi...

Computer algebra systems often have to deal with piecewise continuous functions. These are, for example, the absolute value function, signum, piecewise defined functions but also functions that are the supremum or infimum of two functions. We present a new algebraic approach to these types of problems. This paper presents a normal form for a function ring containing piecewise polynomial functio...

The development of advanced metering technologies makes demand response (DR) able to provide fast response services, e.g., primary frequency control. It is recognized that DR can contribute to the primary frequency control like thermal generators. This paper proposes a day-ahead scheduling method that considers DR as a frequency control resource, so that the DR resources can be dispatched prope...

The α-reformulation (αR) technique can be used to transform any nonconvex twice-differentiable mixedinteger nonlinear programming problem to a convex relaxed form. By adding a quadratic function to the nonconvex function it is possible to convexify it, and by subtracting a piecewise linearization of the added function a convex underestimator will be obtained. This reformulation technique is imp...

A class of piecewise continuous, piecewise C transformations on the interval [O, l] is shown to have absolutely continuous invariant measures.

According to conventional neural network theories, single-hidden-layer feedforward networks (SLFNs) with additive or radial basis function (RBF) hidden nodes are universal approximators when all the parameters of the networks are allowed adjustable. However, as observed in most neural network implementations, tuning all the parameters of the networks may cause learning complicated and inefficie...

A continuous system can be though of as a hybrid automaton with: Assumption 1 u and d are piecewise continuous functions of time. Remarks: The trivial dependence on q will be dropped from now on. Strictly speaking execution takes place over a hybrid time trajectory of the form 0 ; 0 0 ]] 1 ; 0 1 ] : : : , where u and d are continuous over each interval (refer to lecture 8). Notice that x() is c...

We use a front tracking algorithm to explicitly construct entropy solutions for the LighthillWhitham-Richards traffic flow model with a flow-density relationship that is piecewise quadratic, continuous, non-smooth, and non-concave. The solution is exact if the initial condition is piecewise linear and the boundary conditions are piecewise constant. The algorithm serves as a fast and accurate so...