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Detekce objektů v laserových skenech pomocí konvolučních neuronových sítí
Zelenák, Michal ; Kodym, Oldřich (oponent) ; Veľas, Martin (vedoucí práce)
Táto práca je zameraná na segmentáciu vozovky v laserových skenoch, pomocou konvolučnej neurónovej siete. Pre riešenie uvedeného problému, ktorý nájde uplatnenia v oblastiach údržby vozovky, boli použité konvolučné neurónové siete pre ich flexibilitu a rýchlosť. Práca prináša implementáciu a modifikácie existujúcej metódy, ktorá daný problém rieši pomocou plne prepojenej konvolučej neurónovej siete. Týmito modifikáciami sú napríklad použitie rôznych parametrov pre chybovú funkciu, použitie iného počtu tried v modeli a datasete. Vplyv modifikácií bol experimentálne overený a bola dosiahnutá presnosť 96.12%, a hodnota F-measure 95.02%.
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Detekce objektů v laserových skenech pomocí konvolučních neuronových sítí
Zelenák, Michal ; Kodym, Oldřich (oponent) ; Veľas, Martin (vedoucí práce)
Táto práca je zameraná na segmentáciu vozovky v laserových skenoch, pomocou konvolučnej neurónovej siete. Pre riešenie uvedeného problému, ktorý nájde uplatnenia v oblastiach údržby vozovky, boli použité konvolučné neurónové siete pre ich flexibilitu a rýchlosť. Práca prináša implementáciu a modifikácie existujúcej metódy, ktorá daný problém rieši pomocou plne prepojenej konvolučej neurónovej siete. Týmito modifikáciami sú napríklad použitie rôznych parametrov pre chybovú funkciu, použitie iného počtu tried v modeli a datasete. Vplyv modifikácií bol experimentálne overený a bola dosiahnutá presnosť 96.12%, a hodnota F-measure 95.02%.
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Velocity measurements on continuous micro water jet using fluorescent PMMA seeding particles
Zeleňák, Michal ; Ščučka, Jiří ; Souček, Kamil
The paper deals with application of optical diagnostic techniques for velocity\nmeasurements of continuous micro water jet. The combination of Particle image\nvelocimetry, Particle tracking velocimetry, Laser induced fluorescence and\nShadowgraphy methods have been applied together with the use of fluorescent\nPMMA seeding particles. An experimental closed water circuit was designed with\na low-pressure water pump, and a series of experiments was conducted to\nmeasure the velocity of seeding particles in the water jet flow below the diamond\nmicro-nozzle outlet. The basic principles of the methods used in experiments are\nalso described.
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Measurement and analysis of abrasive particles velocities in AWJ
Zeleňák, Michal ; Foldyna, Josef ; Martinec, Petr ; Cárach, J. ; Gurková, Lucie ; Nováková, Daria
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an injection system has not been completed yet. New designs of the injection cutting head based on numerical simulation of the flow provide important information about processes occurring during the formation of AWJ. Detailed knowledge of velocities of abrasive particles during the abrasive water jet generation is vital for the verification of the numerical model. The aim of the experimental work was to test the applicability of the LIF (Laser Inducted Fluorescence) technique combined with the PTV (Particle Tracking Velocity) processing algorithms to analyze particle velocities at the output of the focusing tube. The combination of commonly used water pressures with abrasive mass flow rate was tested and the obtained results of abrasive particles velocities are presented in this paper.
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Visualisation and quantitative analysis of flat continuous water jet structure
Ščučka, Jiří ; Zeleňák, Michal ; Foldyna, Josef ; Lehocká, D. ; Votavová, H.
The results of an experiment focused on the visualisation and structural analysis of flat continuous high-speed water jet used in descaling process are presented in this paper. The aim of the work was to test the applicability of the shadowgraph technique, combined with image processing and analysis methods, to visualise the water jet structure and analyse its main quantitative parameters. Volume percentage of water and air in the water jet structure, size of droplets and water bunches and other parameters were measured on digital images taken at various distances from the nozzle outlet. Knowledge of the water jet structure below the nozzle can facilitate an optimal setting of technological conditions of the water jetting with respect to the maximum disintegration effect on treated material. The described methods can also provide important information for development of new nozzles or entire water jetting tools for disintegration of materials.
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Preliminary study using pulsating water jet for bone cement demolition
Hloch, Sergej ; Kloc, J. ; Foldyna, Josef ; Pude, F. ; Smolko, I. ; Zeleňák, Michal ; Sitek, Libor ; Hvizdoš, P. ; Monka, P. ; Monková, K. ; Kozak, D. ; Stoić, A. ; Sedmak, A. ; Milosevic, M. ; Lehocká, D. ; Mihalčinová, E.
The paper deals with the study of using the selective property of ultrasonic pulsating water jet for the disintegration of bone cement which creates the interface between femoral stem and trabecular bone tissue. For investigation, commercial bone cements were used. Bone cements were tested by nanoindentation in order to review their mechanical properties. A representative sample Palacos R+G was selected for disintegration of bone cement. Bone cements samples fixed between two plexiglasses were disintegrated using ultrasonic water jet and water jet generated by self-resonating nozzle at the pressure level of 20 MPa. Visualisation of bone cement demolition was provided with high speed 1 kHz cameras with two led pulsed sources. Potential were observed for using of pulsating water jet for bone cement demoliton during femoral stem extraction.
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