49 research outputs found

    Broadcasting Monitoring of SSR Transponders in Real Space

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    The article presents a method that allows achieved the greater completeness of the record during the reconstruction of emitted SSR transponder messages captured by terrestrial receivers. The method is based on a fusion of records from several ground-based receivers. The second part of the article presents and evaluates the results achieved using this method on the network of the low-cost ADS-B receivers in the Department of Air Transport, Czech Technical University in Prague Faculty of Transportation Sciences. Some inevitable phenomena are demonstrated that this measurement method brings

    Factor validity and internal consistency of the Expressions of Spirituality Inventory – Revised (ESI-R) : The Czech context

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    This study is the first attempt to examine the validity of the Expressions of Spirituality Inventory (ESI-R) for use in the Czech context. Data were obtained via online survey from 222 emerging adults (18-25 years; 82% women), with a background in helping professions. Structural equation modelling revealed reasonably good support for structural validity of the ESI-R factor model. In addition, all of the dimension scores showed acceptable interitem consistency. However, our findings presumptively point to problems with measurement non-invariance as some items were observed to correlate with different dimensions than expected. Overall, these findings are consistent with cross-cultural research on ESI-R showing that the ESI-R has structural but not measurement invariance at the item and dimension level and provide support for further use of the ESI-R with Czech respondents

    Backup alternatives for 110 kV lines

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    The paper describes backup alternatives for 110 kV lines. Line backup is one of input parameters used to optimise the renovation of 110 kV lines. The optimisation is based on the principle of reliability centred maintenance (RCM) which depends on the technical condition and importance of a particular element. The paper starts with illustrating the method of reliability schemes. This method enables the evaluation of failure-free operation probability. The probability of a failure-free operation can be estimated for all backup types of 110 kV lines existing in the distribution network. To compare different backup alternatives, type lines were selected and calculated with. The results of the method helped estimate the effects of a line failure for a particular distribution district

    COUPLED SIMULATION FOR FIRE-EXPOSED STRUCTURES USING CFD AND THERMO-MECHANICAL MODELS

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    Fire resistance of buildings is based on fire tests in furnaces with gas burners. However, the tests are very expensive and time consuming. This article presents a coupled simulation of an element loaded by a force and a fire loading. The simulation solves a weakly-coupled problem, consisting of fluid dynamics, heat transfer and mechanical model. The temperature field from the computational fluid dynamics simulation (CFD) creates Cauchy and radiative boundary conditions for the thermal model. Then, the temperature field from element is passed to the mechanical model, which induces thermal strain and modifies material parameters. The fluid dynamics is computed with Fire Dynamics Simulator and the thermo-mechanical task is solved in OOFEM. Both softwares are interconnected with MuPIF python library, which allows smooth data transfer across the different meshes, orchestrating simulations in particular codes, exporting results to the VTK formats and distributed computing

    MUPIF WORKFLOW EDITOR AND AUTOMATIC CODE GENERATOR

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    Integrating applications or codes into MuPIF API Model enables easy integration of such APIs into any workflow representing complex multiphysical simulation. This concept of MuPIF also enables automatic code generation of the computational code for given workflow structure. This article describes a ’workflow generator’ tool for the code generation together with ’workflow editor’ graphical interface for interactive definition of the workflow structure and the inner data dependencies. The usage is explained on a thermo-mechanical simulation

    Driving locus of control : The Czech adaptation

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    Objectives. This study attempts to introduce the Driving Locus of Control (DLoC), a method focused on the internal or external source of attribution of the driving behaviour, to the Czech context. This study also relates DLoC to attitudes towards autonomous vehicles (AVs). Participants and setting. Out of the general population, 59 inquirers personally interviewed (CAPI) 1 065 respondents (49% women) in the age range between 15 and 92 years (M = 50, SD = 17). The respondents were sampled via multistage random sampling procedure, based on the list of addresses in the Czech Republic. Hypotheses. The authors hypothesised to replicate the original two-factor structure of the DLoC Scale and that the higher levels of internal DLoC result in not considering the improvement in traffic safety as the AVs replace human drivers. Statistical analysis. Confirmatory factor analysis was used to analyse the factor structure of DLoC Scale. Hypotheses related to the empirical validity of the method were assessed via structural equation modelling. The reliability of DLoC Scale was calculated in terms of internal consistency (McDonald coefficient). Results. Confirmatory factor analysis revealed reasonably good support for structural validity of the one-dimensional DLoC-CZ15 factor model (χ2 = 426.967, df = 90, CFI = 0.964, TLI = 0.958, SRMR = 0.066, RMSEA = 0.065). In addition, the one-dimensional DLoC-CZ15 factor model showed acceptable internal consistency - ω = 0.9 (95% CI [0.89, 0.91]). The structural equation modelling found a relationship between DLoC and some of the items capturing attitudes towards AVs, too. Study limitations. The analysed data were obtained via interviews between respondents and inquirers. As a result, the study does not contain indicators of empirical validity measured by a methodologically different approach, such as an observation of driving behaviour

    DNS Firewall Data Visualization

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    Common security tools generate a lot of data suitable for further analysis. However, the raw form of the data is often too complex and useful information gets lost in a large volume of records. In this paper, we propose a system for visualization of the data generated by a DNS firewall and outline a process of visually emphasizing information important to incident handlers. Our prototype suggests that such visualization is possible, keeping the balance between the amount of displayed information and the level of detail

    Steel elements with timber fire protection - experiment and numerical analysis

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    Steel structural elements are sensitive to elevated temperatures, while timber elements have good thermal insulation properties. Timber material can fulfill the role of fire protection of steel members. The effect of the protection is demonstrated on an experiment with three beams with different levels of the protection, placed into a horizontal furnace. The experimental task was also numerically analysed with standard computational approach given by the Eurocode [1, 2], which leads to an interesting comparison, as the calculation is supposed to provide higher temperatures and larger deformations compared to the experimental data

    FIRE PROTECTION OF STEEL ELEMENTS USING LIGHTWEIGHT HYBRID CEMENT MORTAR

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    Material properties of steel structures are significantly reduced at high temperatures, so a fire protection has strong positive impact on the fire resistance of the structure. Fire resistance of steel elements can be increased using a layer of cement-based materials as a fire protection. Most of commonly used cement-based materials do not withstand high temperatures without noticeable reduction of mechanical properties. Hybrid cement showed some interesting properties in the way of resistance to high temperatures and adhesion to steel surfaces, thus its behavior during fire exposure should be investigated. One experimental analysis with numerical simulation is presented in this article. It examines thermal material properties of lightweight hybrid cement mortar with expanded perlite from a simple experiment with a lab gas burner

    Tram-train system as a potential transport solution for the Olomouc Region

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    The article is focused on the frequently discussed topic of suburban and regional railway system modernization comparing different approaches to consider by local authorities. To make a precedent and to better contribute to practical problems, a middle-sized city of Olomouc (Czechia) is chosen to demonstrate the upgraded regional transport system design with respect to the regional specifics and utilizing of the current railway and tramway infrastructure. With a new, innovative approach to the potential tram-train implementation in the Olomouc Region, the technical and operational features of the current tram-train systems and vehicles are analysed. By implementing the most suitable ones, the regional tram-train system proposal in the conditions of Olomouc may serve as a guide for similar planned systems in the countries with limited legislative and technical experience regarding the tram-train systems (especially in Central Europe), their suitability for the region, their design, and introduction. For the qualitative assessment of the different relevant approaches, a comparative analysis is used. As a result of the analysis, a tram-train system is recommended for the further transport planning stages as it significantly improves both urban and suburban public transport in the Olomouc Region by increasing their average speed and accessibility. For better financial and technical implementation, the project is divided into several stages. Unlike the already presented solutions, it combines shorter travel times of the regional rail and the populated area coverage reached by regional buses and serves as both an attractive and financially sane extension of a regional public transport system
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