Jožef Stefan Institute

About: Jožef Stefan Institute is a facility organization based out in Ljubljana, Slovenia. It is known for research contribution in the topics: Liquid crystal & Dielectric. The organization has 3828 authors who have published 12614 publications receiving 291025 citations.

Origin of apparent colossal dielectric constants

Abstract: Experimental evidence is provided that colossal dielectric constants ${\ensuremath{\varepsilon}}^{\ensuremath{'}}g~1000,$ sometimes reported to exist in a broad temperature range, can often be explained by Maxwell-Wagner-type contributions of depletion layers at the interface between sample and contacts or at grain boundaries. We demonstrate this on a variety of different materials. We speculate that the largest intrinsic dielectric constant observed so far in nonferroelectric materials is of order ${10}^{2}.$

Is Combining Classifiers with Stacking Better than Selecting the Best One

Abstract: We empirically evaluate several state-of-the-art methods for constructing ensembles of heterogeneous classifiers with stacking and show that they perform (at best) comparably to selecting the best classifier from the ensemble by cross validation. Among state-of-the-art stacking methods, stacking with probability distributions and multi-response linear regression performs best. We propose two extensions of this method, one using an extended set of meta-level features and the other using multi-response model trees to learn at the meta-level. We show that the latter extension performs better than existing stacking approaches and better than selecting the best classifier by cross validation.

Lysosomal cysteine proteases: facts and opportunities.

Abstract: From their discovery in the first half of the 20th century, lysosomal cysteine proteases have come a long way: from being the enzymes non-selectively degrading proteins in lysosomes to being those responsible for a number of important cellular processes. Some of the features and roles of their structures, specificity, regulation and physiology are discussed.

Accurate Density Functional with Correct Formal Properties: A Step Beyond the Generalized Gradient Approximation

Abstract: We approximate the exchange-correlation energy of density functional theory as a controlled extrapolation from the slowly varying limit. While generalized gradient approximations (GGA's) require only the local density and its first gradient as input, our meta-GGA also requires the orbital kinetic energy density. Its exchange energy component recovers the fourth-order gradient expansion, while its correlation energy is free of self-interaction error. Molecular atomization energies and metal surface energies are significantly improved over GGA, while lattice constants are little changed.