A Hybrid Method for Solving Absolute Value Equations
Rohn, Jiří
2014 - English Keywords: absolute value equation; iterative method; hybrid method Available in a digital repository NRGL A Hybrid Method for Solving Absolute Value Equations

Rohn, Jiří
Ústav informatiky, 2014

Inherent Logic and Complexity
Žák, Stanislav
2014 - English Keywords: branching programs; complexity; logic Available in a digital repository NRGL Inherent Logic and Complexity

Žák, Stanislav
Ústav informatiky, 2014

A modified limited-memory BNS method for unconstrained minimization based on the conjugate directions idea
Vlček, Jan; Lukšan, Ladislav
2014 - English Keywords: unconstrained minimization; variable metric methods; limited-memory methods; the BFGS update; conjugate directions; numerical results Available in a digital repository NRGL A modified limited-memory BNS method for unconstrained minimization based on the conjugate directions idea

Vlček, Jan; Lukšan, Ladislav
Ústav informatiky, 2014

Towards Low-Dimensional Gaussian Process Metamodels for CMA-ES
Bajer, Lukáš; Holeňa, Martin
2014 - English Gaussian processes and kriging models has attracted attention of researchers from different areas of black-box optimization, especially since Jones’ introduction of the Efficient Global Optimization (EGO) algorithm. However, current implementations of the EGO or real-world applications are rather few. We conjecture that the EGO is not suitable for higher-dimensional optimization and try to investigate whether hybridization of a low-dimensional local optimization with the current state-of-the-art continuous black-box optimizer CMA-ES (Covariance Matrix Adaptation Evolution Strategy) could help. In this paper, only a first proposal of such a GP/CMA-ES connection is described and some preliminary tests are presented. Keywords: CMA-ES; Gaussian processes; global optimization; surrogate model; metamodel Available in digital repository of the ASCR Towards Low-Dimensional Gaussian Process Metamodels for CMA-ES

Gaussian processes and kriging models has attracted attention of researchers from different areas of black-box optimization, especially since Jones’ introduction of the Efficient Global Optimization ...

Bajer, Lukáš; Holeňa, Martin
Ústav informatiky, 2014

Interpreting and Clustering Outliers with Sapling Random Forests
Kopp, Martin; Pevný, T.; Holeňa, Martin
2014 - English The main objective of outlier detection is finding samples considerably deviating from the majority. Such outliers, often referred to as anomalies, are nowadays more and more important, because they help to uncover interesting events within data. Consequently, a considerable amount of statistical and data mining techniques to identify anomalies was proposed in the last few years, but only a few works at least mentioned why some sample was labelled as an anomaly. Therefore, we propose a method based on specifically trained decision trees, called sapling random forest. Our method is able to interpret the output of arbitrary anomaly detector. The explanation is given as a subset of features, in which the sample is most deviating, or as conjunctions of atomic conditions, which can be viewed as antecedents of logical rules easily understandable by humans. To simplify the investigation of suspicious samples even more, we propose two methods of clustering anomalies into groups. Such clusters can be investigated at once saving time and human efforts. The feasibility of our approach is demonstrated on several synthetic and one real world datasets. Keywords: anomaly detection; anomaly interpretation; clustering; decision trees; feature selection; random forest Available in digital repository of the ASCR Interpreting and Clustering Outliers with Sapling Random Forests

The main objective of outlier detection is finding samples considerably deviating from the majority. Such outliers, often referred to as anomalies, are nowadays more and more important, because they ...

Kopp, Martin; Pevný, T.; Holeňa, Martin
Ústav informatiky, 2014

Online System for Fire Danger Rating in Colorado
Vejmelka, Martin; Kochanski, A.; Mandel, J.
2014 - English A method for the data assimilation of fuel moisture surface observations has been developed for the purpose of incorporation in wildfire forecasting and fire danger rating. In this work, we describe the method itself and also an online computer system that implements the method and combines it with the Real-Time Mesoscale Analysis to track local weather conditions and estimate the fuel moisture content in the state of Colorado. We discuss the construction of the system and future development. Keywords: fire danger; fuel moisture; data assimilation; remote automated weather stations; real-time mesoscale analysis; software; nebezpečí požáru; vlhkost paliva; asimilace dat; vzdálené automatické meteostanice Available in digital repository of the ASCR Online System for Fire Danger Rating in Colorado

A method for the data assimilation of fuel moisture surface observations has been developed for the purpose of incorporation in wildfire forecasting and fire danger rating. In this work, we describe ...

Vejmelka, Martin; Kochanski, A.; Mandel, J.
Ústav informatiky, 2014

Influence of Metric on Classification Error of Distance-Based Classifiers
Jiřina, Marcel
2014 - English Five types of classifiers that use sample distances for class estimation of an unknown sample was tested. Each classifier was tested with fifteen different metrics on 24 classification tasks from the UCI Machine Learning Repository. The metrics were compared and the best of them was found for each classifier. Surprisingly, the best metrics for all five types of classifiers is the Hassanat metrics. Classifiers were also compared and ranked according to their classification ability. Wilcoxon Test and Friedman Aligned test were used for statistical evaluation. Keywords: multidimensional data; classifier; distance; metrics; Hassanat metrics; k-NN; IINC Available in a digital repository NRGL Influence of Metric on Classification Error of Distance-Based Classifiers

Five types of classifiers that use sample distances for class estimation of an unknown sample was tested. Each classifier was tested with fifteen different metrics on 24 classification tasks from the ...

Jiřina, Marcel
Ústav informatiky, 2014

IINC classifier for MS Excel. The principle, method and Program
Jiřina, Marcel
2014 - English Keywords: multivariate data; classification; Excel; Hassanat’s metric Available in a digital repository NRGL IINC classifier for MS Excel. The principle, method and Program

Jiřina, Marcel
Ústav informatiky, 2014

Propagation of elastic waves in fractured media under a self-gravity field
Nedoma, Jiří
2013 - English V článku se řeší šíření elastických vln v rozlámaném elastickém prostředí, které se nachází v gravitačním poli. Modelová úloha je rozšířením úlohy šíření seismických vln v zemském tělese. Numerické řešení modelového problému je založeno na variační formulaci kontaktní úlohy a SEM metodě. Propagation of elastic waves in fractured media, that is, in broken media with contact boundaries between bodies being in mutual contacts, and under self-gravity eld will be discussed. Such problems are e.g. problems of global seismology. For numerical solution the spectral-element method can be used with a great merit. The paper extends the global seismology results to problems modelling elastic wave propagations in the global Earth with a fractured lithosphere and under a self-gravitation. Numerical solution of the model problem, based on its variational formulation and the spectral-element method, is presented. Keywords: propagation of elastic waves; global model of the Earth; fractured lithosphere; elastic and fluid rheologies; self-gravitating; contact problems; variational and numerical solutions; algorithm Available in a digital repository NRGL Propagation of elastic waves in fractured media under a self-gravity field

V článku se řeší šíření elastických vln v rozlámaném elastickém prostředí, které se nachází v gravitačním poli. Modelová úloha je rozšířením úlohy šíření seismických vln v zemském tělese. Numerické ...

Nedoma, Jiří
Ústav informatiky, 2013

Soupis publikovaných prací pana prof. Ing. Ladislava Lukšana, DrSc. zpracovaný ke dni 14. září 2013 knihovnou Ústavu informatiky AV ČR, v. v. i. k příležitosti 70. narozenin autora
Nývltová, Ludmila; Ramešová, Nina
2013 - Czech Keywords: bibliografie Available in a digital repository NRGL Soupis publikovaných prací pana prof. Ing. Ladislava Lukšana, DrSc. zpracovaný ke dni 14. září 2013 knihovnou Ústavu informatiky AV ČR, v. v. i. k příležitosti 70. narozenin autora

Nývltová, Ludmila; Ramešová, Nina
Ústav informatiky, 2013