Two econometric issues arise in the estimation of complete systems of producer or consumer demands when many non-negativity constraints are binding for a large share of observations, as frequently occurs with micro-level data. The rst is computational. The econometric model is essentially an endogenous switching regimes model which requires the evaluation of multivariate probability integrals. ...

In this paper, we present a detailed evaluation of cross wavelet analysis of bivariate time series. We develop a statistical test for zero wavelet coherency based on Monte Carlo simulations. If at least one of the two processes considered is Gaussian white noise, an approximative formula for the critical value can be utilized. In a second part, typical pitfalls of wavelet cross spectra and wave...

We describe novel ways of gradient estimation and tri-linear interpolation for a real-time volume rendering system, using coherency between rays. We show simulation results that compare the proposed methods to traditional algorithms and present them in the context of Cube-3, a special-purpose architecture capable of rendering 5123 ldbit per voxel datasets at over 20 frames per second.

We present a method for visualizing large voxel volumes based on optimized ray-casting. Other than conventional methods casting a ray for each pixel on the screen, our method only casts one ray per column and then traverses the voxel volume in a front to back manner. This can be done efficiently as our data is encoded by run-length-encoding (RLE), reducing the overall cost for the traversal. To...

Introduction Traditionally, the analysis of seismic data involved looking for continuous events on seismic data, from which structural and stratigraphic features could be mapped. However, we are also interested in mapping discontinuous features such as faults and fractures. A method for identifying these discontinuities was first introduced by Bahorich and Farmer (1995) and called the coherency...

This contribution presents a stochastic analysis model, aiming at segmentation of the motion vector fields from compressed video sequences into regions of coherent motion. We propose a stochastic motion coherency model based on parametric affine motion. This model applies the 2-D GibbsMarkov random field to identify motion-coherent smoothcontour regions and corresponding motion model estimates....

Query translation in cross-language information retrieval (CLIR) can be done by employing dictionaries, aligned corpora, or machine translators. Scarcity of aligned corpora for various domains in many language pairs intensifies the importance of dictionary-based CLIR which motivates us to use only a bilingual dictionary and two independent collections in source and target languages for query tr...