Completion of the mixed unit interval graphs hierarchy

We describe the missing class of the hierarchy of mixed unit interval graphs, generated by the intersection graphs of closed, open and one type of half-open intervals of the real line. This class lies strictly between unit interval graphs and mixed unit interval graphs. We give a complete characterization of this new class, as well as quadratic-time algorithms that recognize graphs from this class and produce a corresponding interval representation if one exists. We also mention that the work in arXiv:1405.4247 directly extends to provide a quadratic-time algorithm to recognize the class of mixed unit interval graphs.Comment: 17 pages, 36 figures (three not numbered). v1 Accepted in the TAMC 2015 conference. The recognition algorithm is faster in v2. One graph was not listed in Theorem 7 of v1 of this paper v3 provides a proposition to recognize the mixed unit interval graphs in quadratic time. v4 is a lot cleare

String graphs. I. The number of critical nonstring graphs is infinite

AbstractString graphs (intersection graphs of curves in the plane) were originally studied in connection with RC-circuits. The family of string graphs is closed in the induced minor order, and so it is reasonable to study critical nonstring graphs (nonstring graphs such that all of their proper induced minors are string graphs). The question of whether there are infinitely many nonisomorphic critical nonstring graphs has been an open problem for some time. The main result of this paper settles this question. In a later paper of this series we show that recognizing string graphs is NP-hard

Reconstruction of a Planetary Gearbox for the Earth Stabilizer

Diplomová práce se zabývá rekonstrukcí planetové převodovky zařízení pro stabilizaci zeminy. V úvodu práce je popsán princip stabilizace zeminy. Dále jsou popsány zařízení používaná pro stabilizaci a jejich pohony. Proveden je rozbor pohonu zařízení a výpočet silových poměrů. Je navrženo ozubení dle původní dokumentace a následně je provedena pevnostní kontrola tohoto ozubení. Unašeč satelitních kol je přepracován tak, aby byl vyrobitelný dostupnými technologiemi. Těsnění a ložiska jsou nahrazena normalizovanými a dostupnými. Je provedena změna spojů evolventním drážkováním a kontrola drážkování. Závěrem práce je vytvořena výkresová dokumentace sestavy a vybraných dílů.Master thesis deals with reconstruction of planetary gearbox for for the Earth Stabilizer. The introduction of the thesis describes the principle of soil stabilization. In addition, is made introduction of devices used for earth stabilization and their drives. An analysis of the stabilizer drive and the calculations of the drive forces. Gears are designed according to the original documentation and is checked the strength of the gears. The planetary gear carrier is redesigned to make it with available technologies. Seals and bearings are replaced by standard and available. A change of joints is made by involute grooving. In the end are created drawings of the assembly and selected parts.347 - Katedra částí a mechanismů strojůvýborn

Acceleration of Graphics Algorithms by NEON Coprocessor

Cílem této práce je prozkoumat možnosti koprocesoru NEON. Porovnávají se grafické algoritmy napsané v jazyce C, jazyce symbolických adres, jazyce C s využitím intrinsických funkcí a automaticky vektorizovaný kód. Hlavním zjištěním je, že jde zkrátit délku výpočtu až 60 krát a díky tomu by bylo možné tyto algoritmy provádět v reálném čase na HD videu.The aim of this work is to examine capabilities of NEON coprocessor. Various implementations of the same algorithm are compared: language C, assembly language, language C with intinsic functions and automatically vectorized code. Main conslusion is, that computation time can be reduced up to 60 times, allowing real-time HD video processing.