Modern communication systems are adopting new Morden technologies like OFDM (Ortogonal Frequency Division Multiplexing) and LDPC (Low Density Parity Check) for achieving high performance, low Bit Error Rate (BER) and high capacity. The OFDM communication is inspired effectively from the frequencies of channel over the network. In this type of network some kind of distortion occurs over the chan...

For high dimensional problems, such as approximation and integration, one cannot afford to sample on a grid because of the curse of dimensionality. An attractive alternative is to sample on a low discrepancy set, such as an integration lattice or a digital net. This article introduces a multivariate fast discrete Walsh transform for data sampled on a digital net that requires only O(N logN) ope...

The Lebesgue constant is a valuable numerical instrument for linear interpolation because it provides a measure of how close the interpolant of a function is to the best polynomial approximant of the function. Moreover, if the interpolant is computed by using the Lagrange basis, then the Lebesgue constant also expresses the conditioning of the interpolation problem. In addition, many publicatio...

A multilevel sparse kernel-based interpolation (MLSKI) method, suitable for moderately high-dimensional function interpolation problems has been recently proposed in [15]. The method uses both level-wise and direction-wise multilevel decomposition of structured or mildly unstructured interpolation data sites in conjunction with the application of kernel-based interpolants with different scaling...

The construction of a polynomial interpolant to data given at finite pointsets in IR (or, most generally, to data specified by finitely many linear functionals) is considered, with special emphasis on the linear system to be solved. Gauss elimination by segments (i.e., by groups of columns rather than by columns) is proposed as a reasonable means for obtaining a description of all solutions and...

We present a decision procedure for the problem of, given a set of regular expressions R1, . . . , Rn, whether R = R1∩· · ·∩Rn is empty. Our solver, revenant, finitely unrolls automata for R1, . . . , Rn, encoding each as a set of propositional constraints. If a SAT solver determines satisfiability then R is non-empty. Otherwise our solver uses unbounded model checking techniques to extract an ...

We present preliminary results from a method for estimating the optimal effective permittivity for reconstructing microwave-radar images. Using knowledge of how microwave-radar images are formed, we identify characteristics that are typical of good images, and define a fitness function to measure the relative image quality. We build a polynomial interpolant of the fitness function in order to i...

Although EL is a popular logic used in large existing knowledge bases, to the best of our knowledge no procedure has yet been proposed that computes uniform EL interpolants of general EL terminologies. Up to now, also the bounds on the size of uniform EL interpolants remain unknown. In this paper, we propose an approach based on proof theory and the theory of formal tree languages to computing ...

Interpolation-based model-checking and acceleration techniques have been widely proved successful and efficient for reachability checking. Surprisingly, these two techniques have never been combined to strengthen each other. Intuitively, acceleration provides under-approximation of the reachability set by computing the exact effect of some control-flow cycles and combining them with other trans...

Scattered Data Interpolation Using an Alternate Differential Equation Interpolant Gonzalo A. Ramos Master of Science Graduate Department of Computer Science University of Toronto 2001 We investigate the performance of DEI, an approach [9] that computes off-mesh approximations of PDE solutions, and can also be used as a technique for scattered data interpolation. We compare the new approach with...