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    Localizing multiple radiation sources actively with a particle filter
    (Elsevier, 2025-02-01) Lázna, Tomáš; Žalud, Luděk
    We discuss the localization of radiation sources whose number and other relevant parameters are not known in advance. The data collection is ensured by an autonomous mobile robot that performs a survey in a defined region of interest populated with static obstacles. The measurement trajectory is information-driven rather than pre-planned, and the localization exploits a regularized particle filter estimating the sources’ parameters continuously. Regarding the dynamic robot control, this switches between two modes, one attempting to minimize the Shannon entropy and the other aiming to reduce the variance of expected measurements in unexplored parts of the target area; both of the modes maintain safe clearance from the obstacles. The performance of the algorithms was tested in a simulation study based on real-world data acquired previously from three radiation sources exhibiting various activities. Our approach reduces the time necessary to explore the region and to find the sources by approximately 40 %; at present, however, the method is unable to reliably localize sources that have a relatively low intensity. In this context, additional research has been planned to increase the credibility and robustness of the procedure and to improve the robotic platform autonomy.
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    Comparison of Pilots' Abilities Connected with Military Flight Training using Simulation Technologies
    (IEEE, 2021-06-08) Jirgl, Miroslav; Jalovecký, Rudolf
    This paper presents evaluation and consequent comparison of pilots' abilities and limitations in different stages of training. The results are based on modelling and assessing of pilots' behavior during simulated flight. For these purposes, the tests were performed with two groups of pilots - students of the first and the last study year at University of Defense in Brno. The results provide observable differences in behavioral parameters such as reaction delay, or quality of control. These parameters could be used for objective evaluation of influence of pilot training on pilot's abilities and limits.
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    A Real Model of a Micro-Grid to Improve Network Stability
    (MDPI, 2017-07-30) Marcoň, Petr; Szabó, Zoltán; Veselý, Ivo; Zezulka, František; Sajdl, Ondřej; Roubal, Zdeněk; Dohnal, Přemysl
    This paper discusses the smart energy model of a smart grid using a significant share of renewable energy sources combined with intelligent control that processes information from a smart metering subsystem. An algorithm to manage the microgrid via the demand-response strategy is proposed, accentuating the requirement that the total volume of energy produced from renewable sources is consumed. Thus, the system utilizes the maximum of renewable sources to reduce CO2 emissions. Another major benefit provided by the algorithm lies in applying the current weather forecast to predict the amount of energy in the grid; electricity can then be transferred between the local and the main backup batteries within the grid, and this option enables the control elements to prepare for a condition yet to occur. Individual parts of the grid are described in this research report together with the results provided by the relevant algorithm.
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    A New Method to Perform Direct Efficiency Measurement and Power Flow Analysis in Vibration Energy Harvesters
    (MDPI, 2021-03-30) Kunz, Jan; Fialka, Jiří; Pikula, Stanislav; Beneš, Petr; Krejčí, Jakub; Klusáček, Stanislav; Havránek, Zdeněk
    Measuring the efficiency of piezo energy harvesters (PEHs) according to the definition constitutes a challenging task. The power consumption is often established in a simplified manner, by ignoring the mechanical losses and focusing exclusively on the mechanical power of the PEH. Generally, the input power is calculated from the PEH’s parameters. To improve the procedure, we have designed a method exploiting a measurement system that can directly establish the definition-based efficiency for different vibration amplitudes, frequencies, and resistance loads. Importantly, the parameters of the PEH need not be known. The input power is determined from the vibration source; therefore, the method is suitable for comparing different types of PEHs. The novel system exhibits a combined absolute uncertainty of less than 0.5% and allows quantifying the losses. The approach was tested with two commercially available PEHs, namely, a lead zirconate titanate (PZT) MIDE PPA-1011 and a polyvinylidene fluoride (PVDF) TE LDTM-028K. To facilitate comparison with the proposed efficiency, we calculated and measured the quantity also by using one of the standard options (simplified efficiency). The standard concept yields higher values, especially in PVDFs. The difference arises from the device’s low stiffness, which produces high displacement that is proportional to the losses. Simultaneously, the insufficient stiffness markedly reduces the PEH’s mechanical power. This effect cannot be detected via the standard techniques. We identified the main sources of loss in the damping of the movement by the surrounding air and thermal losses. The latter source is caused by internal and interlayer friction.
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    Design and performance evaluation of smart vibration sensor for industrial applications with built-in MEMS accelerometers
    (IEEE, 2018-12-05) Doseděl, Martin; Havránek, Zdeněk
    Paper deals with design and experimental evaluation of performance of a smart vibration sensor for industrial applications based on two built-in MEMS accelerometers and signal pre-processing using a low power microcontroller. Sensor contains one single axis low noise broadband MEMS accelerometer with analog output and one tri-axial low noise MEMS accelerometer with a narrower frequency range and digital SPI interface. Data from both MEMS devices are processed using TI MSP430 microcontroller. The smart sensor has digital output interface, which allows easier connection to the subsequent data processing system and ensures higher immunity to electro-magnetic interference. The smart sensor is intended for measurements of overall vibration velocity in frequency range defined in ISO standard up to 1 kHz while applications above ISO frequency range up to 10 kHz for acceleration measurement used in bearing diagnostics are also expected. Performance parameters of each sensing device builtin inside the common housing have been evaluated in two steps. The first step dealt with precise measurement of metrological parameters of each device including nominal value of vibration sensitivity in the main axis, its frequency dependence and transverse sensitivity with cross-axial excitation. These measurements were performed on the accredited calibration system SPEKTRA CS18, which offers outstanding measurement uncertainty, and achieved results confirmed the correctness of the design of the whole system and its critical parts. The second step was intended for evaluation of the sensor in practical application, where comparison between both internal sensing systems and external reference accelerometer was performed on test stand with industrial actuators to perform real vibration measurement task. Also this step indicated suitability of the designed sensor for these range of applications. Further and more detailed evaluation is expected in the near future when complete signal processing and autodiagnostic features will be implemented in the system thanks to utilization of two separated sensing elements.