Tomasz Danek

Tomasz Danek
AGH · Department of Geoinformatics and Applied Computer Science

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67
Publications
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224
Citations

Publications

Publications (67)
Article
Full-text available
Despite the very restrictive laws, Krakow is known as the city with the highest level of air pollution in Europe. It has been proven that, due to its location, air pollutants are transported to this city from neighboring municipalities. In this study, a complex geostatistical approach for spatio-temporal analysis of particulate matter (PM) concentr...
Article
Full-text available
Key message Recently observed temporal changes in the climate-growth relationship of larch in the Polish Sudetes suggest growth limitations in the future. Abstract Larches in the Sudetes are very sensitive to the currently changing climatic factors, and an extreme negative response to drought is observed. In this study, temporal changes in the cli...
Article
Full-text available
The historical analysis of particulate matter (PM) concentration proved that pro-clean-air legislation and grassroots movement have a positive impact on air quality in Krakow. However, when the temperature drops in late autumn, winter, and early spring, the problem of smog still occurs in the city. In a 24-hours averaging period, the concentration...
Article
We present a strategy for selecting the values of model parameters by comparing walkaway Vertical Seismic Profiling data with a multilayered model in the context of Bayesian Information Criterion. We consider -wave traveltimes and assume elliptical polar velocity dependence. A model with different propagation speeds, depending on the angle of propa...
Article
Full-text available
Joint inversion is a widely used geophysical method that allows model parameters to be obtained from the observed data. Pareto inversion results are a set of solutions that include the Pareto front, which consists of non-dominated solutions. All solutions from the Pareto front are considered the most feasible models from which a particular one can...
Article
Full-text available
In this paper, we present a detailed analysis of the public data provided by low-cost sensors (LCS), which were used for spatial and temporal studies of air quality in Krakow. A PM (particulate matter) dataset was obtained in spring in 2021, during which a fairly strict lockdown was in force as a result of COVID-19. Therefore, we were able to separ...
Article
Full-text available
In this paper, we present a detailed analysis of walkaway vertical seismic profiling (VSP) data, which can be used to obtain Thomsen parameters using P-wave-only inversion. Data acquisition took place in difficult field conditions, which influenced the quality of the data. Therefore, this paper also shows a seismic data processing scheme that allow...
Preprint
Full-text available
We combine power-meter measurements with GPS measurements to study the model that accounts for the use of power by a cyclist. The model takes into account the change in elevation and speed along with adverse effects of air, rolling and drivetrain resistance. The focus is on estimating the resistance coefficients using numerical optimization techniq...
Article
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Key message Extreme growth reaction analysis shows that larches in the Sudetes are more vulnerable to climate changes, but negative extreme responses will also be observed in the Carpathians in the near future. Abstract Pointer year analysis provides information on extreme tree-ring growth reactions, which can significantly improve the interpretat...
Preprint
Full-text available
We present a strategy for selecting the values of elasticity parameters by comparing walk-away vertical seismic profiling data with a multilayered model in the context of Bayesian Information Criterion. We consider $P$-wave traveltimes and assume elliptical velocity dependence. The Bayesian Information Criterion approach requires two steps of optim...
Preprint
Power-meter measurements together with GPS measurements are used to study the model that accounts for the use of power by a cyclist. The focus is on estimating the coefficients of the air, rolling and drivetrain resistance, uncertainties of these estimates, as well as relations between them. Expressions used in the main text are derived in the appe...
Preprint
Power-meter measurements are used to study a model that accounts for the use of power by a cyclist. The focus is on relations between rates of change of model quantities, such as power and speed, both in the context of partial derivatives, where other quantities are constant, and Lagrange multipliers, where other quantities vary to maintain the imp...
Article
Full-text available
Obtaining the most accurate and detailed subsurface information from seismic surveys is one of the main challenges for seismic data processing, especially in the context of complex geological conditions (e.g., mountainous areas). The correct calculation of static corrections allows for the reliable processing of seismic data. This, in turn, leads t...
Presentation
Full-text available
Obtaining most accurate and detailed subsurface information based on seismic surveys is one of the main challenges for seismic processing, especially in case of complicated and varying geology typical for mountainous areas (e.g. Carpathians). Proper static corrections calculation allows for more accurate and reliable seismic processing and interpre...
Presentation
Full-text available
It is a common knowledge that proper inclinations and azimuth angle determination is a critical step in processing and interpretation of walk-away VSP data. Additionally, an in-depth analysis of the uncertainty of these interpreted values requires the introduction of measurement errors. In this contribution, we present a statistical analysis of obt...
Presentation
Full-text available
Pareto joint inversion for two or more data sets is an attractive and promising tool which eliminates target functions weighting and scaling, providing a set of acceptable solutions composing a Pareto front. In former author's study MARIA (Modular Approach Robust Inversion Algorithm) was created as a flexible software based on global optimization e...
Article
In the paper, the authors used data acting on the base of public procurement ZDN/014/140/2016 and related permission.
Article
Full-text available
It is a common knowledge that proper inclinations and azimuth angle determination is a critical step in processing and interpretation of walk-away VSP data. Additionally, an in-depth analysis of the uncertainty of these interpreted values requires the introduction of measurement errors. In this contribution, we present a statistical analysis of obt...
Article
Full-text available
Inversion of velocity parameters for the walkaway VSP data in a multilayered medium can be impeded by velocity gradients and anisotropy in some layers. A problem occurs if we compare velocities obtained from borehole seismic profiling which are equal to their vertical components with the velocities calculated with paths coming from far offsets wher...
Article
Full-text available
Pareto joint inversion for two or more data sets is an attractive and promising tool which eliminates target functions weighing and scaling, providing a set of acceptable solutions composing a Pareto front. In former author’s study MARIA (Modular Approach Robust Inversion Algorithm) was created as a flexible software based on global optimization en...
Article
Full-text available
In this paper, we present an analysis of borehole seismic data processing procedures required to obtain high-quality vertical stacks and polarization angles in the case of walkaway VSP (vertical seismic profile) data gathered in challenging conditions. As polarization angles are necessary for more advanced procedures like anisotropy parameters dete...
Article
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In this paper, we examine the applicability of the approximation, fg‾≈f‾g‾\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\overline{f g}\approx \overline{f}\,\overline{g...
Article
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We use the Pareto Joint Inversion, together with the Particle Swarm Optimization, to invert the Love and quasi-Rayleigh surface-wave speeds, obtained from dispersion curves, in order to infer the elasticity parameters, mass densities and layer thickness of the model for which these curves are generated. For both waves, we use the dispersion relatio...
Article
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It is common to assume that a Hookean solid is isotropic. For a generally anisotropic elasticity tensor, it is possible to obtain its isotropic counterparts. Such a counterpart is obtained in accordance with a given norm. Herein, we examine the effect of three norms: the Frobenius 36-component norm, the Frobenius 21-component norm and the operator...
Article
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The use of nonlinear anisotropic diffusion algorithm for advanced seismic signal processing in the complicated geological region of Carpathian Foredeep was examined. This technique allows for an improvement of seismic data quality and for more accurate interpretation by the recovery of a significant amount of structural information in the form of a...
Article
Full-text available
In the medium composed of parallel sedimentary layers, model of elliptic anisotropy is often better approximation of real conditions than simple layers with constant velocity. In such model a velocity is described with 3 parameters: a, b (responsible for vertical velocity and its gradient) and χ - elliptic anisotropy coefficient, describing changes...
Article
Full-text available
An anisotropic elasticity tensor can be approximated by the closest tensor belonging to a higher symmetry class. The closeness of tensors depends on the choice of a criterion. We compare the closest isotropic tensors obtained using four approaches: the Frobenius 36-component norm, the Frobenius 21-component norm, the operator norm and the L2 slowne...
Article
Full-text available
In this paper, a Pareto inversion based global optimization approach, to obtain results of joint inversion of two types of geophysical data sets, is formulated. 2D magnetotelluric and gravity data were used for tests, but presented solution is flexible enough to be used for combination of any kind of two or more target functions, as long as misfits...
Article
Full-text available
We examine the Backus averaging method - which, in general, allows one to represent a series of parallel layers by a transversely isotropic medium-using a repetitive shale-sandstone model. To examine this method in the context of experimental data, we perturb the model with random errors, in particular, the values of layer thicknesses and elasticit...
Article
Full-text available
A b s t r a c t A generally anisotropic elasticity tensor can be related to its closest counterparts in various symmetry classes. We refer to these counterparts as effective tensors in these classes. In finding effective tensors, we do not assume a priori orientations of their symmetry planes and axes. Knowledge of orientations of Hookean solids al...
Article
Full-text available
We introduce the effective elasticity tensor of a chosen material-symmetry class to represent a measured generally anisotropic elasticity tensor by minimizing the weighted Frobenius distance from the given tensor to its symmetric counterpart, where the weights are determined by the experimental errors. The resulting effective tensor is the highest-...
Article
Full-text available
A generally anisotropic elasticity tensor, which might be obtained from physical measurements, can be approximated by a tensor belonging to a particular material-symmetry class; we refer to such a tensor as the effective tensor. The effective tensor is the closest to the generally anisotropic tensor among the tensors of that symmetry class. The con...
Chapter
Full-text available
Analysis of logs of remote network services is one of the most difficult and time consuming task—its amount and variety of types are still growing. With the increasing number of services increases the amount of logs generated by computer programs and their analysis becomes impossible for the common user. However, the same analysis is essential beca...
Chapter
The presented paper describes the ad hoc prepared virtualisation solution for laboratory used for short term and rapidly changing additional courses for postgraduate students. Modern computer labs in today’s higher education facilities are equipped with dozens of computers and peripherals. In order to take full advantage of their potential, proper...
Article
Seismic migration is the most important procedure in hydrocarbons prospecting and is aimed to correct reconstruction of underground structure. It is one of the most complicated and time-consuming task of whole seismic processing chain. Many types of seismic migration algorithms were created and implemented in both commercial and free software. One...
Article
Full-text available
We consider the problem of representing a generally anisotropic elasticity tensor, which might be obtained from physical measurements, by a tensor belonging to a chosen material symmetry class, so-called ‘effective tensor'. Following previous works on the subject, we define this effective tensor as the solution of a global optimization problem for...
Article
We propose a new method to separate the incident and reflected arrivals and correct for the post-critical phase shift in wide angle reflection imaging situations. Such a situation arises, for example, in quasi-vertical geological fault imaging using data from small earthquakes. Major faults are often associated with a high degree of seismic activit...
Chapter
Seismic waveform inversion is a problem with demand of high computational power. This demand can be fulfilled by supercomputers or by the modern graphics units. However GPU solution is much more accessible and cheaper. To implement this problem on GPUs one of GPGPU environments should be used. The newest one is OpenCL. To obtain higher speedup the...
Article
Full-text available
Bayesian interpretation of a three-parameter model of anisotropy and inhomogeneity for a VSP data set obtained in the Western Canada Basin indicates that introduction of the anisotropy parameter is justified by the data to a high grade of evidence. The acquisition geometry is a key factor in the resolving power of the data, and hence in deciding on...
Article
Full-text available
Air pollution emissions were not continually monitored in the Upper Silesian Industrial District (USID), southern Poland, and data is only available for the last 20 years. Long-lasting and severe tree ring reductions in pines growing 5-20 km north of the USID area recorded particularly high levels of air pollution emissions in the period 1950-1990....
Article
Full-text available
Throughout the growth of a mineral exploration site, geological ore deposit models are developed based on available data and subsequent interpretations. The accuracy of these models is crucial when used to determine if a deposit is economic. 3D geological Earth models typically comprise wireframe surfaces that represent the geological contacts betw...
Article
Inversion of magnetotelluric (MT) data is usually based on finding local minima. This approach required the construction of initial model which should be close to final. In this paper global solution is proposed. Method combining particle swarm optimization and underparametrized Bayesian inversion was used. Efficiency of such approach was tested on...
Article
Bayesian inversion of geophysical data has many advantages over the classic deterministic approach. Basins of attraction of global solutions are more likely to be found, solution uncertainty can be quantified, and proper parametrizations consistent with the resolving power of the data can be chosen using Bayesian information criteria. Large sets of...
Conference Paper
Full-text available
This paper presents preliminary results of studies concerning possibilities of high performance processing of satellite images using graphics processing units. Even if numerical procedures used for this kind of computation are not complicated and fast, size of typical satellite scene makes them time consuming. This problem is especially troublesome...
Article
The aim of this study was to assess the impact of climatic factors (temperature and precipitation) on tree ring width of larches from stands localised in southern part of Poland. Total ring as well as early- and latewood widths were taken in consideration. At the beginning authors used only standard processing and methods. Classic approach were ins...
Article
In presented paper we examined the influence of anisotropy of geological medium cm seismic wave propagation. The analysis of synthetic seismograms and modelled snapshots can be very interesting not only for theoretical studies but also for solving real, production problems in oil industry and can answer the question if special processing has to be...
Chapter
Full-text available
In this article efficiency of using component-based software for seismic wave field modeling is presented. The most common component solutions like: .NET, Java and Mono were analyzed for various operating systems and hardware platform combinations. Obtained results clearly indicate that the component approach is able to give satisfactory results in...
Article
Full-text available
The results of application of multichannel Kalman filtering to reduction of uncorrelated noise in magnetotelluric recordings are discussed in this article. Magnetotelluric method of Earth structure recognition is shortly presented together with the its most popular measurement method called the remote reference method. The basic theory of nonstatio...
Article
Full-text available
Artificial intelligence methods for MT data processing are proposed. Distortions having a complex structure created by external artificial sources such as, for example, passing train were investigate. In the first part of this paper the time intervals with such type of distortions were found by using a special neuronal system. Next for time interva...
Conference Paper
General-purpose computing on graphics processing units (GPGPU) is a fast developing method of high performance computing (HPC). In some cases even a low-end video card can be several to dozens times faster than a modem CPU core. Seismic wave filed modeling is one of the problems of this kind. But in some modern methods of seismic exploration or sei...
Conference Paper
GPGPU - general-purpose computing on graphics processing units is a very effective and inexpensive way of dealing with time consuming computations. In some cases even a low end GPU can be a dozens of times faster than a modern CPUs. Utilization of GPGPU technology can make a typical desktop computer powerful enough to perform necessary computations...
Conference Paper
Full-text available
An implementation and performance analysis of heat transfer modeling using most popular component environments is a scope of this article. The computational problem is described, and the proposed solution of decomposition for parallelization is shown. The implementation is prepared for MS .NET, Sun Java and Mono. Tests are done for various operatin...
Article
The paper presents estimation of ground vibration by means of full wave field modeling. A geological model from the Rudna copper mine was employed, and an inhomogeneous subsurface layer was added to it. A staggered-grid finite-difference method was applied to numerical solution of the wave equation. As compared to the traditional finite-difference...
Article
Pines growing close to Tarnowskie Góry Chemical Plant and Miasteczko Śla̧skie Zinc Foundry produced reduced tree rings from 1950 to 1990 when compared with pines growing 60 km from the factories. Tree ring reductions occurred concurrently with the operation of the chemical plant and zinc foundry. Ring widths of the sampled pines are inversely propo...
Article
The thin-layer build of the Carpathian Foredeep Miocene formations and large petrophysical parameter variation cause seismic images of gas-saturated zones to be ambiguous, and the location of prospection wells on the basis of anomalous seismic record is risky. A method that assists reservoir interpretation of standard recorded seismic profiles (P w...
Conference Paper
In the paper the effectiveness analysis of the seismic waves modeling in anisotropic media are discussed. The computations were performed on 31 nodes PC cluster working under Linux Fedora operating system. The efficiency analysis of the computation time for a typical seismic set-up consisted of 10 shoot points was made. The considerations are made...
Article
Full-text available
The inversion of geophysical data depends on the availability of a priori information on the geology of the earth, inversion method chosen, and the appropriate definition of parameters of the model. Traditionally, ID magnetotelluric data have been inverted by the trial-and-error method, which employs iterated, linearized inversion methods. However,...
Conference Paper
Full-text available
In this paper a possibility of neural network application to data processing in magnetotelluric method is studied. The modular neural system, consisting of three multi-layer neural networks, is used for obtaining geoelectric model of lithosphere basing on amplitude and phase MT curves. Cases of two and three flat lithosphere layers are considered.

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Projects (3)
Project
The goal was to implement and deploy a new module to MARIA software - forward solver for magnetometry and make some test on synthetic data.
Archived project
To create software solving problem of joint inversion of two or more geophysical data sets (in this case we used MT & gravimetry) in Pareto mode using PSO method as optimization engine.
Project
I'm working on a Ph.D. doing forward modelling and joint inversion of Love and quasi-Rayleigh (like Rayleigh only in layered media) waves, initially for isotropic media but eventually for layered transversely isotropic media, including the case where one of the layers is a Backus averaged equivalent medium of a series of thin isotropic or transversely isotropic layers.