The thermal regime of ice pits of the Borec hill
Türkott, L.; Martinčíková, Eva; Potop, V.
2014 - anglický The ecological stability of the sites with stenoec organisms is important factor for maintaining them at given location. Phonolite system of the Borec hill creates a unique labyrinth of vents. Thermal anomalies occur during the year in the fissure system and create specific microclimate. Flow direction is given by the temperature gradient inside and outside of the system. The lower part of fissure system is located in the debris fields, while the upper part on top of the hill. Phonolite rocks are cooled down by air streaming from the debris fields during the winter. Direction of the air flow changes in the spring and summer. The cold air is exhaled from these vents on the lower parts of system and creates ice pits with the typical vegetation. Klíčová slova: ice pit; air temperature; Boreč hill; ventalore Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd. The thermal regime of ice pits of the Borec hill

The ecological stability of the sites with stenoec organisms is important factor for maintaining them at given location. Phonolite system of the Borec hill creates a unique labyrinth of vents. Thermal ...

Türkott, L.; Martinčíková, Eva; Potop, V.
Ústav informatiky, 2014

Inconspicuous Appeal of Amorphous Computing Systems
Wiedermann, Jiří
2014 - anglický Amorphous computing systems typically consist of myriads of tiny simple processors that are randomly distributed at fixed positions or move randomly in a confined volume. The processors are “embodied” meaning that each of them has its own source of energy, has a “body” equipped with various sensors and communication means and has a computational control part. Initially, the processors have no identifiers and from the technological reasons, in the interest of their maximal simplicity, their computational, communication, sensory and locomotion (if any) parts are reduced to an absolute minimum. The processors communicate wirelessly, e.g., in an airborne medium they communicate via a short-range radio, acoustically or optically and in a waterborne medium via molecular communication. In the extreme cases the computational part of the processors can be simplified down to probabilistic finite state automata or even combinatorial circuits and the system as a whole can still be made universally programmable. From the theoretical point of view the structure and the properties of the amorphous systems qualify them among the simplest (non-uniform) universal computational devices. From the practical viewpoint, once technology will enable a mass production of the required processors a host of new applications so far inaccessible to classical approaches to computing will follow. Klíčová slova: amorphous computing; computational universality; computational complexity Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd. Inconspicuous Appeal of Amorphous Computing Systems

Amorphous computing systems typically consist of myriads of tiny simple processors that are randomly distributed at fixed positions or move randomly in a confined volume. The processors are “embodied” ...

Wiedermann, Jiří
Ústav informatiky, 2014

Highly Robust Estimation of the Autocorrelation Coefficient
Kalina, Jan; Vlčková, Katarína
2014 - anglický The classical autocorrelation coefficient estimator in the time series context is very sensitive to the presence of outlying measurements in the data. This paper proposes several new robust estimators of the autocorrelation coefficient. First, we consider an autoregressive process of the first order AR(1) to be observed. Robust estimators of the autocorrelation coefficient are proposed in a straightforward way based on robust regression. Further, we consider the task of robust estimation of the autocorrelation coefficient of residuals of linear regression. The task is connected to verifying the assumption of independence of residuals and robust estimators of the autocorrelation coefficient are defined based on the Durbin-Watson test statistic for robust regression. The main result is obtained for the implicitly weighted autocorrelation coefficient with small weights assigned to outlying measurements. This estimator is based on the least weighted squares regression and we exploit its asymptotic properties to derive an asymptotic test that the autocorrelation coefficient is equal to 0. Finally, we illustrate different estimators on real economic data, which reveal the advantage of the approach based on the least weighted squares regression. The estimator turns out to be resistant against the presence of outlying measurements. Klíčová slova: time series; autoregressive process; linear regression; robust econometrics Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd. Highly Robust Estimation of the Autocorrelation Coefficient

The classical autocorrelation coefficient estimator in the time series context is very sensitive to the presence of outlying measurements in the data. This paper proposes several new robust estimators ...

Kalina, Jan; Vlčková, Katarína
Ústav informatiky, 2014

Representations of Boolean Functions by Perceptron Networks
Kůrková, Věra
2014 - anglický Limitations of capabilities of shallow perceptron networks are investigated. Lower bounds are derived for growth of numbers of units and sizes of output weights in networks representing Boolean functions of d variables. It is shown that for large d, almost any randomly chosen Boolean function cannot be tractably represented by shallow perceptron networks, i.e., each its representation requires a network with number of units or sizes of output weights depending on d exponentially Klíčová slova: perceptron networks; model complexity; Boolean functions Plné texty jsou dostupné v digitálním repozitáři Akademie Věd. Representations of Boolean Functions by Perceptron Networks

Limitations of capabilities of shallow perceptron networks are investigated. Lower bounds are derived for growth of numbers of units and sizes of output weights in networks representing Boolean ...

Kůrková, Věra
Ústav informatiky, 2014

A Weather Risk Prediction System for Road Trip Planning
Krč, Pavel; Fuglík, Viktor; Juruš, Pavel; Kasanický, Ivan; Konár, Ondřej; Pelikán, Emil; Eben, Kryštof; Šucha, M.
2014 - anglický The paper presents first ideas of the MEDARD-RODOS project. The aim of the project is to develop a decision support system for road trip planning, reflecting the weather risks predicted from the NWP models implemented in the MEDARD system (www.medard-online.cz) and using the traffic information from the RODOS project (www.centrum-rodos.cz). Klíčová slova: weather; prediction; risk; system; road; planning; MEDARD; RODOS; NWP Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd. A Weather Risk Prediction System for Road Trip Planning

The paper presents first ideas of the MEDARD-RODOS project. The aim of the project is to develop a decision support system for road trip planning, reflecting the weather risks predicted from the NWP ...

Krč, Pavel; Fuglík, Viktor; Juruš, Pavel; Kasanický, Ivan; Konár, Ondřej; Pelikán, Emil; Eben, Kryštof; Šucha, M.
Ústav informatiky, 2014

Noise revealing in Golub-Kahan bidiagonalization as a mean of regularization in discrete inverse problems
Kubínová, Marie; Hnětynková, Iveta
2014 - anglický Klíčová slova: ill-posed problems; regularization; Krylov subspace Plné texty jsou dostupné v digitálním repozitáři NUŠL Noise revealing in Golub-Kahan bidiagonalization as a mean of regularization in discrete inverse problems

Kubínová, Marie; Hnětynková, Iveta
Ústav informatiky, 2014

On three equivalent methods for parameter estimation problem based on spatio-temporal FRAP data
Matonoha, Ctirad; Papáček, Š.
2014 - anglický Klíčová slova: inverse problem formulation; Tikhonov regularizaton; least-squares problem Plné texty jsou dostupné v digitálním repozitáři NUŠL On three equivalent methods for parameter estimation problem based on spatio-temporal FRAP data

Matonoha, Ctirad; Papáček, Š.
Ústav informatiky, 2014

Explaining Anomalies with Sapling Random Forests
Pevný, T.; Kopp, Martin
2014 - anglický The main objective of anomaly detection algorithms is finding samples deviating from the majority. Although a vast number of algorithms designed for this already exist, almost none of them explain, why a particular sample was labelled as an anomaly. To address this issue, we propose an algorithm called Explainer, which returns the explanation of sample’s differentness in disjunctive normal form (DNF), which is easy to understand by humans. Since Explainer treats anomaly detection algorithms as black-boxes, it can be applied in many domains to simplify investigation of anomalies. The core of Explainer is a set of specifically trained trees, which we call sapling random forests. Since their training is fast and memory efficient, the whole algorithm is lightweight and applicable to large databases, datastreams, and real-time problems. The correctness of Explainer is demonstrated on a wide range of synthetic and real world datasets. Klíčová slova: anomaly explanation; decision trees; feature selection; random forest Plné texty jsou dostupné v digitálním repozitáři Akademie Věd. Explaining Anomalies with Sapling Random Forests

The main objective of anomaly detection algorithms is finding samples deviating from the majority. Although a vast number of algorithms designed for this already exist, almost none of them explain, ...

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

Case Study in Approaches to the Classification of Audiovisual Recordings of Lectures and Conferences
Pulc, P.; Holeňa, Martin
2014 - anglický Several methods for classification of semistructured documents already exist, thus also classifications for individual modalities of multimedia content. However, every classifier can behave differently on different data modalities and can be differently appropriate for classification of the considered multimedia content as a whole. Because of that, relying on a single classifier or a static weighting of the classification of individual modalities is not adequate. The present paper describes a case study in searching for suitable classification methods, and in investigating appropriate methods for the aggregation of their results to determine a final class of a lecture or conference recording. Klíčová slova: multimedial data; classification; ensembles of classifiers Plné texty jsou dostupné v digitálním repozitáři Akademie Věd. Case Study in Approaches to the Classification of Audiovisual Recordings of Lectures and Conferences

Several methods for classification of semistructured documents already exist, thus also classifications for individual modalities of multimedia content. However, every classifier can behave ...

Pulc, P.; Holeňa, Martin
Ústav informatiky, 2014

Meta-Parameters of Kernel Methods and Their Optimization
Vidnerová, Petra; Neruda, Roman
2014 - anglický In this work we deal with the problem of metalearning for kernel based methods. Among the kernel methods we focus on the support vector machine (SVM), that have become a method of choice in a wide range of practical applications, and on the regularization network (RN) with a sound background in approximation theory. We discuss the role of kernel function in learning, and we explain several search methods for kernel function optimization, including grid search, genetic search and simulated annealing. The proposed methodology is demonstrated on experiments using benchmark data sets. Klíčová slova: kernel methods; metalearning; computational intelligence Plné texty jsou dostupné v digitálním repozitáři Akademie Věd. Meta-Parameters of Kernel Methods and Their Optimization

In this work we deal with the problem of metalearning for kernel based methods. Among the kernel methods we focus on the support vector machine (SVM), that have become a method of choice in a wide ...

Vidnerová, Petra; Neruda, Roman
Ústav informatiky, 2014