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SCARA robot homing
Marčonek, Michal ; Burian, František (referee) ; Benešl, Tomáš (advisor)
This thesis deals with the design process of a new home procedure system for the SCARA manipulator from Seiko Epson. At the outset, it was first considered whether to use the original homing system. The principle of the original home procedure was identified, then attempts were made to make it work, but with negative results. For this reason, it was proceeded to create a new homing procedure system. In the theoretical part, the possible homing methods and their properties are explained. The new solution includes the design of new first and second axis sensors, which are solved by STGC absolute sensors. The other two axes are solved by end sensors. It was necessary to modify the cabling and add an input card to the control system. Finally, a Homing function block is implemented to ensure the detection of the manipulator pose after startup.
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Gray code based bitmap compression
Škorvaga, David ; Dvořák, Tomáš (advisor) ; Gregor, Petr (referee)
This thesis deals with a compression of bitmap indexes. Bitmap indexes may be reduced through specialized algorithms which look for long runs of identical bits. To improve the compression ratio, it is useful to reorder the rows of the index. Even though the problem of optimal reordering is NP-hard, there are efficient heuristics which reorder the index in polynominal time. Recent results suggest that Gray code based sorting provides an effective alternative to the classical lexicographical sorting. In this thesis, we replace the classical Gray code with a novel construction which generates a compressed Gray code. We describe this construction in detail and use both real-life and randomly generated datasets to test whether the novel construction is more efficient than the classical one when used in the WAH compression scheme.
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Construction of Gray codes with special properties
Novotný, Tomáš ; Dvořák, Tomáš (advisor) ; Fink, Jiří (referee)
A (cyclic) Gray code is a (cyclic) sequence of all n-bit strings in which consecutive strings differ in a single bit. Ruskey and Savage in 1993 asked whether every matching in a hypercube can be extended to a cyclic Gray code. An affirmative answer is known for perfect matchings (Fink, 2007) while the ge- neral case is still open. The main contribution of this thesis is a generalization of Fink's result to Gray codes with prescribed ends. The characterization of perfect matchings extendable in this way is verified for n = 5 with the assistance of a com- puter, which is useful as a basis for the inductive proof of the general statement. The other part of the thesis is focused on smallest maximal matchings in hyper- cubes which could possibly form especially hard instances of the Ruskey-Savage problem. We devise a novel method which provides - in particular for small di- mensions - maximal matchings of smaller size than the classical asymptotically optimal construction (Forcade, 1973). An adjusted program from the first part is then applied to test the Ruskey-Savage problem over these matchings, however, the extending Gray code is always discovered. 1
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Gray code based bitmap compression
Škorvaga, David ; Dvořák, Tomáš (advisor) ; Gregor, Petr (referee)
This thesis deals with a compression of bitmap indexes. Bitmap indexes may be reduced through specialized algorithms which look for long runs of identical bits. To improve the compression ratio, it is useful to reorder the rows of the index. Even though the problem of optimal reordering is NP-hard, there are efficient heuristics which reorder the index in polynominal time. Recent results suggest that Gray code based sorting provides an effective alternative to the classical lexicographical sorting. In this thesis, we replace the classical Gray code with a novel construction which generates a compressed Gray code. We describe this construction in detail and use both real-life and randomly generated datasets to test whether the novel construction is more efficient than the classical one when used in the WAH compression scheme.
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