Number of found documents: 812
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### Jak jsme (z)řídili ústav aneb Od Centrálního výpočetního střediska ČSAV k Ústavu informatiky AV ČR Šebesta, Václav 2019 - Czech Jak jsme (z)řídili ústav aneb Od Centrálního výpočetního střediska ČSAV k Ústavu informatiky AV ČR Available in a digital repository NRGL Jak jsme (z)řídili ústav aneb Od Centrálního výpočetního střediska ČSAV k Ústavu informatiky AV ČR

Jak jsme (z)řídili ústav aneb Od Centrálního výpočetního střediska ČSAV k Ústavu informatiky AV ČR

Šebesta, Václav
Ústav informatiky, 2019

### Overdetermined Absolute Value Equations Rohn, Jiří 2019 - English We consider existence, uniqueness and computation of a solution of an absolute value equation in the overdetermined case. Keywords: absolute value equations; overdetermined system Available in a digital repository NRGL Overdetermined Absolute Value Equations

We consider existence, uniqueness and computation of a solution of an absolute value equation in the overdetermined case.

Rohn, Jiří
Ústav informatiky, 2019

### Generalization of a Theorem on Eigenvalues of Symmetric Matrices Rohn, Jiří 2019 - English We prove that the product of a symmetric positive semide nite matrix and a symmetric matrix has all eigenvalues real. Keywords: symmetric matrix; positive semide nite matrix; real spectrum Available in a digital repository NRGL Generalization of a Theorem on Eigenvalues of Symmetric Matrices

We prove that the product of a symmetric positive semide nite matrix and a symmetric matrix has all eigenvalues real.

Rohn, Jiří
Ústav informatiky, 2019

### Hybrid Methods for Nonlinear Least Squares Problems Lukšan, Ladislav; Matonoha, Ctirad; Vlček, Jan 2019 - English This contribution contains a description and analysis of effective methods for minimization of the nonlinear least squares function F(x) = (1=2)fT (x)f(x), where x ∈ Rn and f ∈ Rm, together with extensive computational tests and comparisons of the introduced methods. All hybrid methods are described in detail and their global convergence is proved in a unified way. Some proofs concerning trust region methods, which are difficult to find in the literature, are also added. In particular, the report contains an analysis of a new simple hybrid method with Jacobian corrections (Section 8) and an investigation of the simple hybrid method for sparse least squares problems proposed previously in [33] (Section 14). Keywords: numerical optimization; nonlinear least squares; trust region methods; hybrid methods; sparse problems; partially separable problems; numerical experiments Available in a digital repository NRGL Hybrid Methods for Nonlinear Least Squares Problems

This contribution contains a description and analysis of effective methods for minimization of the nonlinear least squares function F(x) = (1=2)fT (x)f(x), where x ∈ Rn and f ∈ Rm, together with ...

Ústav informatiky, 2019

### Sort Program for Real Keys with Linear Time Complexity Jiřina, Marcel 2019 - Czech In this report we present a program for sorting data structures with sorting keys as real numbers, i.e. of type "real" or "float". The basis of the program is a modification of the countingsort algorithm for reals (instead of integers). It uses a comparision-type sorting for small part of data set given. The time complexity of this part of program can be bounded by linear function of n and thus, the total time complexity is also O(n) for n data items. Keywords: sorting; real sorting keys; counting sort Available in a digital repository NRGL Sort Program for Real Keys with Linear Time Complexity

In this report we present a program for sorting data structures with sorting keys as real numbers, i.e. of type "real" or "float". The basis of the program is a modification of the countingsort ...

Jiřina, Marcel
Ústav informatiky, 2019

### Does a Singular Symmetric Interval Matrix Contain a Symmetric Singular Matrix? Rohn, Jiří 2019 - English We consider the conjecture formulated in the title concerning existence of a symmetric singular matrix in a singular symmetric interval matrix. We show by means of a counterexample that it is generally not valid, and we prove that it becomes true under an additional assumption of positive semide niteness of the midpoint matrix. The proof is constructive. Keywords: symmetric interval matrix; singularity; positive semide niteness Available in a digital repository NRGL Does a Singular Symmetric Interval Matrix Contain a Symmetric Singular Matrix?

We consider the conjecture formulated in the title concerning existence of a symmetric singular matrix in a singular symmetric interval matrix. We show by means of a counterexample that it is ...

Rohn, Jiří
Ústav informatiky, 2019

### Transforming hierarchical images to program expressions using deep networks Křen, Tomáš 2018 - English We present a technique describing how to effectively train a neural network given an image to produce a formal description of the given image. The basic motivation of the proposed technique is an intention to design a new tool for automatic program synthesis capable of transforming sensory data (in our case static image, but generally a phenotype) to a formal code expression (i.e. syntactic tree of a program), such that the code (from evolutionary perspective a genotype) evaluates to a value that is similar to the input data, ideally identical. Our approach is partially based on our technique for generating program expressions in the context of typed functional genetic programming. We present promising results evaluating a simple image description language achieved with a deep network combining convolution encoder of images and recurrent decoder for generating program expressions in the sequential prefix notation and propose possible future applications. Keywords: deep networks; automatic program synthesis; image processing Available in a digital repository NRGL Transforming hierarchical images to program expressions using deep networks

We present a technique describing how to effectively train a neural network given an image to produce a formal description of the given image. The basic motivation of the proposed technique is an ...

Křen, Tomáš
Ústav informatiky, 2018

### Nonparametric Bootstrap Techniques for Implicitly Weighted Robust Estimators Kalina, Jan 2018 - English The paper is devoted to highly robust statistical estimators based on implicit weighting, which have a potential to find econometric applications. Two particular methods include a robust correlation coefficient based on the least weighted squares regression and the minimum weighted covariance determinant estimator, where the latter allows to estimate the mean and covariance matrix of multivariate data. New tools are proposed allowing to test hypotheses about these robust estimators or to estimate their variance. The techniques considered in the paper include resampling approaches with or without replacement, i.e. permutation tests, bootstrap variance estimation, and bootstrap confidence intervals. The performance of the newly described tools is illustrated on numerical examples. They reveal the suitability of the robust procedures also for non-contaminated data, as their confidence intervals are not much wider compared to those for standard maximum likelihood estimators. While resampling without replacement turns out to be more suitable for hypothesis testing, bootstrapping with replacement yields reliable confidence intervals but not corresponding hypothesis tests. Keywords: robust statistics; econometrics; correlation coefficient; multivariate data Fulltext is available at external website. Nonparametric Bootstrap Techniques for Implicitly Weighted Robust Estimators

The paper is devoted to highly robust statistical estimators based on implicit weighting, which have a potential to find econometric applications. Two particular methods include a robust correlation ...

Kalina, Jan
Ústav informatiky, 2018

### Detailní simulace proudění, teplot a znečištění vzduchu pro oblast Praha-Dejvice Resler, Jaroslav; Geletič, Jan; Krč, Pavel; Eben, Kryštof 2018 - Czech Simulations of Prague quarter Dejvice were performed with newly developed urban climate model PALM-4U based on LES model PALM. The modelling domain has extent 1000 x 800 m and the resolution of the model was 2 m. Two 24 hours episodes were simulated. The summer episode was intended to assess mainly the UHI effects and the winter episode to assess mainly the air quality issues. Two variants were simulated - the current real situation and the scenario with considered new buildings in the area of Victory Square (Vítězné náměstí). Some comments of the ressults are appended at the end of the report. Keywords: PALM; LES; Urban Heat Island; Urban Air Quality; scenarios assessment Available in digital repository of the ASCR Detailní simulace proudění, teplot a znečištění vzduchu pro oblast Praha-Dejvice

Simulations of Prague quarter Dejvice were performed with newly developed urban climate model PALM-4U based on LES model PALM. The modelling domain has extent 1000 x 800 m and the resolution of the ...

Resler, Jaroslav; Geletič, Jan; Krč, Pavel; Eben, Kryštof
Ústav informatiky, 2018

### Datová sada pro detekci dezinformačního obsahu – případová studie Novičok v Česku Řimnáč, Martin 2018 - Czech Publikování dezinformací na webu hraje stále větší roli, proto vyvstává otázka, jak takovému obsahu čelit, a nebo na jeho potenciální závadnost alespoň upozornit. Propaganda využívá dezinformací k relativizaci skutečností, jejichž popis se snaží většinou nepřímo zpochybnit. Příspěvek formou případové studie v konkrétní kauze formálně popisuje výroky prezentované v článcích publikovaných na webu a to včetně účelu jejich publikování, všímá si některých zajímavých aspektů prezentovaných dezinformací a hledá model pro jejich popis. Cílem příspěvku je informovat o vznikající datové sadě a ilustrovat základní použité dezinformační techniky včetně důsledků jejich použití. The paper presents a case study of the propaganda usage on a real cause of double agent Sergei Skripal. The formal model describing statements published in web articles is announced and particular interesting aspects of used disinformation are provided together with the reasons, why the disinformation is published. The paper is aimed at the presentation of the data collection to have been created and provides a brief discussion on the used propaganda techniques. Keywords: Dezinformace; Web; Entropie; Pravděpodobnost Fulltext is available at external website. Datová sada pro detekci dezinformačního obsahu – případová studie Novičok v Česku

Publikování dezinformací na webu hraje stále větší roli, proto vyvstává otázka, jak takovému obsahu čelit, a nebo na jeho potenciální závadnost alespoň upozornit. Propaganda využívá dezinformací k ...

Řimnáč, Martin
Ústav informatiky, 2018