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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
841

Konstrukce dvouosého suportu vícevřetenového soustružnického automatu / Design of a two-axis multi-spindle lathe carriage

Sedlář, Jiří January 2021 (has links)
This diploma thesis deals with the design of a two-axis multi-spindle lathe carriage. In the first part, there is made a research, and its aim is to find possible variants of design solutions. After the best rated variant was selected, the thesis further continues with the necessary technical calculations of the main design nodes such as a synchronous servomotor, ball screw, linear guide and bearing. The design itself was carried out with regard to calculations and the resulting model was examined in terms of dynamic stability. The subject of examination was to find the natural frequencies of the assembly and to determine the amplitudes of the oscillations which arise from the harmonic excitation force. Finally, Lobe diagrams for grooving and longitudinal turning operations were drawn.
842

Návrh robotické linky pro svařování ocelového rámu / Design of a Robotic Cell for a Steel Frame Welding

Kysela, Martin January 2021 (has links)
The aim of this diploma thesis is to design a cell for robotic arc welding of steel frame. Three possible solutions are provided and one of them is to be chosen to work out. Construction designs of fixture, machine guarding and material racks were created and devices and components required for cell functionality were chosen. All of that with regard to the safety of workplace operators.The result is 3D model of welding cell, it´s implementation and virtual commissioning in the simulation software Process simulate. We will verify the weldability of assigned part, find out the production cycle, eliminate error and lastly the technical and economic evaluation will be work out.
843

Návrh vřeteníku soustruhu / Design of spindle for lathe

Sovadina, František January 2021 (has links)
The thesis deals with the design and construction of headstocks of a turning centre. The aim is to design a spindle with an output of 20 kW and a maximum speed of 5000 1/min. The research part of the thesis is focused on the description of the basic parameters of the headstock and turning centres needed for the construction of the headstock and contains an analysis of the available spindles on the market. The next part of the thesis deals with the selection and calculation of cutting conditions and the necessary parameters. Analytical calculations are then verified using FEM analysis. At the end of the thesis, a 3D model was developed and headstock drawing documentation.
844

Simulace dynamického chování vybavovače jističe / Simulation of circuit breaker maglatch dynamic behaviour

Konšel, Ladislav January 2012 (has links)
This work includes the theory of circuit breaker construction and is focused mainly on overload function. It mainly deals with electronic circuit breakers, i.e. equipped with an electronic trip unit. The work is focused on the part of trip unit - maglatch of trip unit. For the purposes of simulation, the geometric model is created. Maxwell program is used for the simulation. The work describes the options for conditions input which are necessary for simulation. Using the distribution of magnetic field intensity and magnetic flux density in the section of trip unit maglatch is determined by the simulation. Furthermore, the force effects acting on the armature of the maglatch are calculated. Force values and the directions acting on the armature are determined by changing the simulation parameters - shift of the armature and coil current. Simulations are performed both for steady-state and for dynamic simulation – movement of armature is taken into account. The supply source for the maglatch is created by an external circuit.
845

Robotický hráč dámy / Draughts Playing Robot

Štěrba, Ondřej January 2014 (has links)
This thesis describes playing draughts game by 6 axis manipulator Lynxmotion AL5D controlled by ARM Cortex M3 MCU. It involves algorithms for image recognition, artificial intelligence and algorithms for controlling 6 axis manipulator in real-time.
846

Experimentální analýza proudu vzduchu z ofukovače osobního vozu s využitím žárového anemometru a návrh hodnocení kvality ofukovače / Experimental analysis of automobile ventilating outlet air flow using hot wire anemometry and draft of outlet quality rating

Ležovič, Tomáš January 2011 (has links)
The master’s thesis deals with air flow in the interior of automobile Škoda Octavia. The attention is focused only at a side ventilating outlet. Author’s effort was to propose the appropriate criteria for evaluation and assessment of ventilating outlet quality and elaborate the methodology of measurement for these criteria. Then follows the application of the methodology and measurement of velocity field of air flow from the outlet by the method of hot wire anemometry. The thesis also contains comparison of the results with the results attained by the smoke visualization.
847

Modulární systém lineární osy / Modular linear axis

Chlapečka, Tomáš January 2014 (has links)
This thesis contains a structural design of linear axis with a stroke up to 800mm and a maximum load of 800N. The thesis also deals with a modular assembly system of the linear axis based on the structural design. Linear axes can be fitted with rolled, whirled and grinded ball screws with thread pitch 5, 10, 16mm and rolled trapezoidal screws on pitch 4 and 8mm. The stroke of the linear axes can be selected in the range from 200 up to 800 mm, with a maximum load of 800N in all linear dimensions. The feed of linear axis is provided by shaped rolling guide way and four trucks. The modular system offers two servo motors with direct and indirect measuring four stepper engines with indirect measuring. The thesis also includes strength and functional calculations of principal components, graphs of the possible load on linear axis in different positions , durability of the ball screws, maximum speed and feed rate of the chosen screws, data sheet, 3D model, drawings and assembly drawings of the nodes.
848

A Client-Server Solution for Detecting Guns in School Environment using Deep Learning Techniques

Olsson, Johan January 2019 (has links)
Att använda maskininlärning för att detektera vapen eliminerar en konstant mänsklig övervakning, vilket också kan leda till en lägre responstid till polis. I den här rapporten undersöks hur en vapendetektor kan konstrueras och byggas som en del av en klient-server-lösning. / With the progress of deep learning methods the last couple of years, object detectionrelated tasks are improving rapidly. Using object detection for detecting guns in schoolsremove the need for human supervision and hopefully reduces police response time. Thispaper investigates how a gun detection system can be built by reading frames locally andusing a server for detection. The detector is based on a pre-trained SSD model and throughtransfer learning is taught to recognize guns. The detector obtained an Average Precisionof 51.1% and the server response time for a frame of size 1920 x 1080 was 480 ms, but couldbe scaled down to 240 x 135 to reach 210 ms, without affecting the accuracy. A non-gunclass was implemented to reduce the number of false positives and on a set of 300 imagescontaining 165 guns, the number of false positives dropped from 21 to 11.
849

Analyzing pathways from childhood maltreatment to internalizing symptoms and disorders in children and adolescents (AMIS): a study protocol

White, Lars O., Klein, Annette M., Kirschbaum, Clemens, Kurz-Adam, Maria, Uhr, Manfred, Müller-Myhsok, Bertram, Hoffmann, Katrin, Sierau, Susan, Michel, Andrea, Stalder, Tobias, Horlich, Jenny, Keil, Jan, Andreas, Anna, Resch, Leonhard, Binser, Martin J., Costa, Anna, Giourges, Elena, Neudecker, Eva, Wolf, Christiane, Scheuer, Sandra, Ising, Marcus, Klitzing, Kai von January 2015 (has links)
Background: Effective interventions for maltreated children are impeded by gaps in our knowledge of the etiopathogenic mechanisms leading from maltreatment to mental disorders. Although some studies have already identified individual risk factors, there is a lack of large-scale multilevel research on how psychosocial, neurobiological, and genetic factors act in concert to modulate risk of internalizing psychopathology in childhood following maltreatment. To help close this gap, we aim to delineate gender-specific pathways from maltreatment to psychological disorder/resilience. To this end, we examine the interplay of specific maltreatment characteristics and psychological, endocrine, metabolomic, and (epi-)genomic stress response patterns as well as cognitive-emotional/social processes as determinants of developmental outcome. Specifically, we will explore endocrine, metabolomic, and epigenetic mechanisms leading from maltreatment to a higher risk of depression and anxiety disorders.
850

Cortisol Responses to Stress in Allergic Children: Interaction with the Immune Response

Buske-Kirschbaum, Angelika January 2009 (has links)
Allergic manifestations are increasingly common in infants and children. Accumulating evidence suggests that the ‘epidemic’ increase of childhood allergy may be associated with environmental factors such as stress. Although the impact of stress on the manifestation and exacerbation of allergy has been demonstrated, the underlying mechanisms of stress-induced exacerbation are still obscure. A growing number of studies have suggested an altered hypothalamus-pituitary-adrenal (HPA) axis function to stress in allergic children. It is speculated that a dysfunctional HPA axis in response to stress may facilitate and/or consolidate immunological aberrations and thus, may increase the risk for allergic sensitization and exacerbation especially under stressful conditions. In the present review the potential impact of a hyporesponsive as well as a hyperresponsive HPA axis on the onset and chronification of childhood allergy is summarized. Moreover, potential factors that may contribute to the development of an aberrant HPA axis responsiveness in allergy are discussed. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

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