|
Bayesian classification of digital images by web application
Talich, M. ; Böhm, O. ; Soukup, Lubomír
The contribution introduces web application for image classification that has been developed at the Research Institute of Geodesy, Topography and Cartography in the framework of grant project InGeoCalc (supported by Ministry of education of the Czech Republic). The web application is aimed to display, examine and classify digital image data. The data are expected to be obtained from Internet by means of Web Map Services (WMS) or from other sources (possibly non-registered). Image data from different sources can be combined and presented as composition of layers (coverage) with adjustable degrees of transparency. After gathering the data, Bayesian (supervised) classification is applied to distinguish separate regions in the image. User can choose between several classification methods and adjust pertinent parameters. Furthermore, several subsequent basic analytical tools are offered, namely computation of distances, areas or perimeters related to the classified regions, simple statistical summaries about classification results (e.g. distribution of classes, percentage of non-classified regions, etc.). The classification results and registration parameters can be saved for further use. The web application is based on common Internet standards (HTML, Javascript, SVG). The only requirement for running the application is an up-to-date Internet browser supporting SVG (Scalable Vector Graphics). Typical usage of the web application can involve land cover mapping based on satellite or aerial images. The application is available free of charge for any Internet user.
|
|
Convexity in stochastic programming model with indicators of ecological stability
Houda, Michal
We develop an optimization model dealing with construction expenses that are prescribed as a result of the EIA (Environmental Impact Assessment) process. The process is an obligatory part of every large construction project and evaluates possible influences of the project to the environment, including population health, natural and other socio-economic aspects; the result of the process is a set of recommendation and arrangements the construction must meet. Our optimization model incorporates uncertainties in model parameters; we represent them through their probabilistic distribution. Furthermore, to overcome a problem with quantifying subjective utility function of ecological impacts, we measure them by so-called indicators of ecological stability. The resulting problem is stochastic programming problem formulated as (C)VaR model used traditionally in finance area. In our contribution we deal with convexity properties of this problem – these are especially important from the theoretical as well as from the computational point of view.
|
| |
|
Hydrodynamic and Heat Transfer Model of a Gas-Liquid Microreactor
Křišťál, Jiří ; Stavárek, Petr ; Staněk, Vladimír ; Jiřičný, Vladimír ; Simoncelli, A. ; Vanhoutte, D. ; Tarchini, R. ; Talford, M. ; Hass-Santo, K. ; Benzinger, W.
In this contribution we present a hydrodynamic and heat transfer model of a microreactor for a gas-liquid reaction. In the course of formulation of the model, we considered the characteristic features of the studied system – the gas-liquid flow pattern and the change in physical properties induced by pressure and temperature variation along the microreactor. Based on the input information (gas and liquid flow rates, compositions, temperatures), the model calculates the two-phase pressure drop and outlet temperature as the principal result. These results serve as a basis for the design of an intensified pilot scale microreactor.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22012102413550 - PDF
|
| |
|
Thin Film Composite Membrane for Effective Raw Biogas Upgrading to Pipeline Quality Methane
Kárászová, Magda ; Vejražka, Jiří ; Veselý, Václav ; Friess, K. ; Randová, A. ; Jansen, J. C. ; Izák, Pavel
In this contribution we propose a method to upgrade biogas to the same quality of fuel standard natural gas. The latter contains more than 95 vol. % of methane. Using traditional membranes, such concentration of methane in the retentate could only be achieved using a multistep process. A recently proposed method for raw biogas purification from impurities and carbon dioxide by condensing water on swollen thin film composite membranes was found to be highly effective. The hydrophilic reverse osmosis membrane promotes the formation of a very thin selective water layer under condensing conditions below the dew point of the raw biogas feed. The large difference in permeability of the impurities in raw biogas (carbon dioxide, hydrogen sulfide) and methane through the water layer enables upgrading of raw biogas to biomethane quality in a single stage. Contrary to the classical purification processes, the proposed method does not require any biogas pretreatment, which makes this approach economically attractive. It represents an innovative approach to production of biomethane from biogas.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102413470 - PDF
|
|
Process-Based Model of Mixed-Matrix Membrane
Čapek, P. ; Hejtmánek, Vladimír ; Veselý, M. ; Sysel, P. ; Kočiřík, Milan ; Brabec, Libor ; Zikánová, Arlette ; Bernauer, B. ; Fíla, V.
The focus of this contribution was on the formulation and verification of a process-based model of the mixed-matrix membrane that consisted of the polyimide matrix synthesized from the monomers 4,4’-(hexafluoroisopropylidene)diphtalic anhydride and 4,4’-oxydianiline, and silicalite-1. When a solution of a polyimide precursor in N,N-dimethylformamide was ready, silicalite-1 particles were dispersed in the solution and the dispersion was subsequently cast on a Teflon support plate. An initial mass ratio of silicalite-1 and polyimide was about 1:1. After solvent removal, the films were heated in subsequent steps up to 230°C for two hour. From a process-based model point of view, a key operation of the entire synthesis was slow sedimentation of silicalite particles in the viscous solution. Preliminary observation of 2D cuts through the solid membrane in a scanning electron microscope revealed that there were a lot of contacts among the silicalite particles. Therefore, a sequential (ballistic) deposition algorithm, well representing sedimentation in a low-energy environment, was used to create an off-lattice model of spatial distribution of the silicalite particles in the polyimide matrix.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102413461 - PDF
|
|
Theoretical Background for Predicting the Properties of Petroleum Fluids via Group Contribution Methods
Bogdanić, Grozdana ; Pavlíček, Jan ; Wichterle, Ivan
The major problem encountered in the petroleum industry lies in the proper thermodynamic representation of rather complex fluids. In this work, the UNIFAC group contribution method for predicting the properties of such fluids has been exploited as a basis for their description in terms of model compounds. Standard thermodynamic procedures are used to estimate the critical properties, acentric factors, and molecular weights for the model compounds. In such a way, the already available generalized methods can be used for calculations of the phase equilibrium in complex petroleum mixtures.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22012102413400 - PDF
|
|
New Roman Period settlement finds from Prague-Kbely
Malyková, Drahomíra ; Bursák, D. ; Pecinovská, Monika
Presented rescue excavations took place in north-eastern part of Prague in the year 2007 within the parish of Prague-Kbely. Most of the features and artifacts belong to the Bronze Age and the late Iron Age. In this contribution authors focus only on the part of archaeological record that brought some evidence on settlement activities datable to the Roman Period. Approximately a half of the artifacts come from eight sunken features, the other part was found widespread in the wide unstratified layer, so any house or farmstead layout is hardly recognizable. Among the common pottery sherds that belong typologically to the end of 2nd-4th Century AD and bear typical signs of Germanic pottery were found also some finds of Roman-provincial provenience. Due to the small dimensions and absence of more detailed typological traces is hard to say something more concrete about these in Bohemia rarely found artifacts. Important finds also present the metallic artifacts, mostly from 2nd and 3rd Century AD.
|
|
Comparison of composite material degradation assesment methods using acoustic analysis and laser vibrometry
Urushadze, Shota ; Šperl, Martin ; Kytýř, D. ; Valach, J. ; Fíla, T.
Assessment of degradation rate of material can be carried out by many experimental techniques differing in complexity and sophistication. A relatively simple method based on acoustic analysis is described in this contribution. Degradation of material’s properties due to fatigue loading is detectable in decrease of their modulus of elasticity that can be derived from natural frequencies of specimens. These measurements utilize self-designed device capable of specimen excitation and acquisition of its vibration. The recorded signal is then processed by spectral analysis enabling determination of natural frequencies. Usefulness of the above mentioned acoustic method can be seen in the fact that the measured changes of material’s parameters are comparable to those obtained by laser vibrometry, which is by several orders more expensive technique.
|
guest ::
