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Classification of Czech sign language alphabet letters using cnn – preliminary study
Krejsa, Jiří; Věchet, Stanislav
2020 - English
Abstract: The paper deals with the classification of Czech sign language single hand alphabet letters from static images using convolutional neural network (CNN). Proposed CNN architecture exhibits about 71% successful rate of classifying the letters signed by the person not included in the training data set.
Keywords:
classification; sign language; convolution neural network
Available at various institutes of the ASCR
Classification of Czech sign language alphabet letters using cnn – preliminary study
Abstract: The paper deals with the classification of Czech sign language single hand alphabet letters from static images using convolutional neural network (CNN). Proposed CNN architecture exhibits ...
Human vocal tract models with yielding walls – preliminary experimental results
Radolf, Vojtěch; Horáček, Jaromír; Košina, Jan
2020 - English
Yielding walls of acoustic cavities cause an additional low frequency acoustical – mechanical resonance of the system. This resonance changes also the higher acoustic resonance frequencies. Experimental model of human vocal tract cavities with hard walls has been modified to take into account the compliance of the soft tissue of human vocal tract. The unique experimental set-up has been assembled to study in detail acoustic-structural interaction of the vocal tract cavities with a dynamical system originated in vibration of the soft tissue. The experimental results are in qualitative agreement with the results of mathematical modelling.
Keywords:
biomechanics of voice; vocal tract acoustics; acoustic-structural interaction
Available at various institutes of the ASCR
Human vocal tract models with yielding walls – preliminary experimental results
Yielding walls of acoustic cavities cause an additional low frequency acoustical – mechanical resonance of the system. This resonance changes also the higher acoustic resonance frequencies. ...
Modelling and simulation of self-balanced vertical rigid rotors
Zapoměl, Jaroslav; Kozánek, Jan; Košina, Jan; Cibulka, Jan
2020 - English
Unbalance of rotors of rotating machines is mostly caused by the manufacturing and assembling inaccuracies. In some cases it can be induced by the rotor operation or can be variable during the rotor running. In these cases the classical approach based on attaching the balancing weights to the rotor surface is not efficient. The technological solution is offered by application of a self-balancing device. This paper deals with its design, modelling, and investigation of its functionality in dependence of the rotor operation parameters.
Keywords:
vertical rotors; unbalance; self-balancing device
Available at various institutes of the ASCR
Modelling and simulation of self-balanced vertical rigid rotors
Unbalance of rotors of rotating machines is mostly caused by the manufacturing and assembling inaccuracies. In some cases it can be induced by the rotor operation or can be variable during the rotor ...
Simple model for investigation of aerodynamic coupling in linear blade cascades
Chládek, Štěpán; Pešek, Luděk; Procházka, Pavel P.
2020 - English
Simple viscous-elastic model has been proposed for investigation of aerodynamic coupling in linear blade cascades. One blade is connected with both adjacent blades using idealized springs and dampers which represent viscous fluid. All blades may oscillate with one degree of freedom represented by vertical translation. Energy method using travelling waves model was utilized for aerodynamic damping coefficient derivation. The proposed model does not compute the damping values quantitatively, nevertheless it provides the damping shape analysis. Interesting results are presented within zero and low subsonic flow velocities, where the experiment included velocity flow field measurement.
Keywords:
linear cascade stability; aerodynamic damping; PIV
Available at various institutes of the ASCR
Simple model for investigation of aerodynamic coupling in linear blade cascades
Simple viscous-elastic model has been proposed for investigation of aerodynamic coupling in linear blade cascades. One blade is connected with both adjacent blades using idealized springs and dampers ...
Influencing of the Pile-Up and the Sink-In by the Coefficient of Friction in the Nanoindentation Test
Kovář, J.; Fuis, Vladimír; Čtvrtlík, Radim
2020 - English
The influence of the coefficient of friction between an indenter and a specimen on the height of the pile-up or depth of the sink-in during the nanoindentation test is discussed in this paper. When the indenter is pressed into the hard material, the sink-in behavior causes the bending of the specimen’s surface under the indenter. When the indenter is pressed into the soft material, the deformed material accumulates under the sides of the indenter and makes a pile-up region. The pile-up or sink-in behavior influences the contact area. In this paper, the finite element method was used for calculation of the dependency between the depth of the sink-in or height of the pile-up and the coefficient of friction. The results showed that while there is not any dependency between the friction and the depth of the sink-in, there is a strong dependency between the friction and the height of the pile-up until a specific value of the coefficient of friction. When the pile-up behavior occurs, the friction influences the contact area and should be included into the calculation of the contact area.
Keywords:
nanoindentation; pile-up; sink-in; coefficient of friction; FEM
Available at various institutes of the ASCR
Influencing of the Pile-Up and the Sink-In by the Coefficient of Friction in the Nanoindentation Test
The influence of the coefficient of friction between an indenter and a specimen on the height of the pile-up or depth of the sink-in during the nanoindentation test is discussed in this paper. When ...
Analysis of measurement of temperature dependence inside rubber sample under dynamic harmonic load
Šulc, Petr; Pešek, Luděk; Bula, Vítězslav; Šnábl, Pavel; Cibulka, Jan; Košina, Jan
2020 - English
This work deals with the preparation and methodology of temperature measurement inside a rubber sample. In this paper, a rubber sample with temperature sensors is described and a description with a temperature measurement scheme under torsional dynamic stress with the possibility of measurement in a temperature chamber is proposed. Large torsional deformations are considered for harmonic torsional loads. The reason for these measurements is to determine the temperature dependence and sensitivity of the heat output parameters.
Keywords:
heat flow; temperature; Fourier equation; heat conduction
Available at various institutes of the ASCR
Analysis of measurement of temperature dependence inside rubber sample under dynamic harmonic load
This work deals with the preparation and methodology of temperature measurement inside a rubber sample. In this paper, a rubber sample with temperature sensors is described and a description with a ...
Applicability of the deterministic methods in blade tip-timing analyses
Maturkanič, Dušan; Procházka, Pavel; Hodboď, Robert; Tchawou Tchuisseu, Eder Batista
2020 - English
The paper describes the possible use of the deterministic methods for analyses of blade vibration. In this respect, the main attention is focused on turbine rotor speed instabilities which could cause inaccuracy of results. The initial method and approach were presented in previous works. The measurements were performed in the Laboratory of the rotational laser vibrometry in the Institute of Thermomechanics, Academy of Sciences of the Czech Republic.
Keywords:
turbine rotor blade vibration; rotating speed instability; vibration diagnostics; blade tip-timing
Available at various institutes of the ASCR
Applicability of the deterministic methods in blade tip-timing analyses
The paper describes the possible use of the deterministic methods for analyses of blade vibration. In this respect, the main attention is focused on turbine rotor speed instabilities which could cause ...
Excitation of wheel blades by axial electromagnet at different regimes
Voronova, Evgeniya; Maturkanič, Dušan
2019 - English
The paper describes the natural frequency identification experiment and results of measuring of blade vibration characteristics excitate by one axial electromagnet at different regimes. The measurements were performed in the laboratory of the rotational laser vibrometry originated at the Institute of Thermomechanics AS CR, v.v.i.
Keywords:
vibration; blade; magnet; frequency
Available at various institutes of the ASCR
Excitation of wheel blades by axial electromagnet at different regimes
The paper describes the natural frequency identification experiment and results of measuring of blade vibration characteristics excitate by one axial electromagnet at different regimes. The ...
Utilization of Convolution Neural Network Based Road Detection in Mobile Robot Localization
Krejsa, Jiří; Věchet, Stanislav
2019 - English
Mobile robot on-road navigation requires fusion of both global and local sensory information with an emphasis on the road detection processing. The paper deals with the road detection based on convolution neural networks (CNN) using commonly available tools such as TensorFlow and Keras. The road is defined by its linear boundaries. Network output is formed by the road definition together with classification parameters and serves as a local sensor in Kalman filter based localization. CNN based road detection is currently capable to successfully detect about 90% of images.
Keywords:
convolution neural network; localization; road detection
Available at various institutes of the ASCR
Utilization of Convolution Neural Network Based Road Detection in Mobile Robot Localization
Mobile robot on-road navigation requires fusion of both global and local sensory information with an emphasis on the road detection processing. The paper deals with the road detection based on ...
Real-time diagnostics for ROS running systems based on probabilistic patterns identification
Věchet, Stanislav; Krejsa, Jiří
2019 - English
Autonomous mobile robots consists of various software modules to achieve given goal, including solving complex navigation tasks as localization, mapping or path planning. These tasks are highly dependent on the quality of data measured and gathered from hardware subsystems. Using Robot Operating System (ROS) as integration basis reduces the development effort and time to market. While ROS framework itself is considered as reliable and stable to run even soft real-time tasks, in case of any internal failures on data misreadings can be problematic to debug or even identify the problem for common user. Due to this unpleasant situations we develop a virtual assistant, internally represented as diagnostic expert system, to help users to identify and possibly fix the problem.
Keywords:
diagnostic expert system; bayesian network; system diagnostic
Available at various institutes of the ASCR
Real-time diagnostics for ROS running systems based on probabilistic patterns identification
Autonomous mobile robots consists of various software modules to achieve given goal, including solving complex navigation tasks as localization, mapping or path planning. These tasks are highly ...
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