We characterize the join-irreducible Medvedev degrees as the degrees of complements of Turing ideals, thereby solving a problem posed by Sorbi. We use this characterization to prove that there are Medvedev degrees above the second-least degree that do not bound any join-irreducible degrees above this second-least degree. This solves a problem posed by Sorbi and Terwijn. Finally, we prove that t...

This paper presents a history of a difficult facility layout problem that falls into the category of the Koopmans-Beckmann variant of the Quadratic Assignment Problem (QAP), wherein 30 facilities are to be assigned to 30 locations. The problem arose in 1972 as part of the design of a German university hospital, Klinikum Regensburg. This problem, known as the Krarup30a upon its inclusion in the ...

This paper presents an enhanced robust phase correlation (ERPC) algorithm for sub-pixel feature matching and its application in target motion estimation for aerial video surveillance. The ERPC can cope with very large motion measurement on the one hand and improve the sub-pixel accuracy by entirely avoiding the ill-posed problem of 2D phase unwrapping in 2D fitting technique of phase correlatio...

mathematical modeling of supply chain operations has proven to be one of the most complex tasks in the field of operations management and operations research. despite the abundance of several modeling proposals in the literature; for vast majority of them, no effective universal application is conceived. this issue renders the proposed mathematical models inapplicable due largely to the fact th...

introduction the main goal of this study was to perform quality control test on all radiography units operating in golestan province of iran. materials and methods forty-four x-ray units were examined based on general accepted programs for quality control. eight parameters including kvp accuracy, kvp reproducibility, ma-time reciprocity, exposure linearity, exposure reproducibility, timer accur...

Context. Weak lensing mass-mapping is a useful tool for accessing the full distribution of dark matter on sky, but because intrinsic galaxy ellipticies, finite fields, and missing data, recovery maps constitutes challenging, ill-posed inverse problem Aims. We introduce novel methodology that enables efficient sampling high-dimensional Bayesian posterior weak problem, relying simulations to defi...

Reducing the numerical precision of forecast model Integrated Forecasting System (IFS) European Centre for Medium-Range Weather Forecasts (ECMWF) from double to single results in significant computational savings without negatively affecting accuracy. The allow increase vertical resolution operational ensemble forecasts 91 137 levels earlier than anticipated and before next upgrade ECMWF's high...

The in uence of small perturbations in the kernel and the righthand side of Symm's boundary integral equation, considered in an ill-posed setting, is analyzed. We propose a modi cation of a fully discrete projection method which is more economical in the sense of complexity and allows to obtain the optimal order of accuracy in the power scale with respect to the level of the noise in the kernel...