1,720,983 research outputs found
3-Coloring Triangle-Free Planar Graphs with a Precolored 9-Cycle
No full textGiven a triangle-free planar graph G and a cycle C of length 9 in G, we characterize all situations where a 3-coloring of C does not extend to a proper 3-coloring of G. This extends previous results for the length of C up to 8
Structure and properties of steel for castings G22NiMoCr5-6
No full textBakalářská práce se věnuje problematice slévárenské technologie se zaměřením na metodu vytavitelného modelu používanou ve firmě Kdynium a.s., kde autor práce působil v rámci praxe v technologickém oddělení. Je provedena analýza struktury a vlastností vysokopevnostní oceli na odlitky G22NiMoCr5-6 s dobrou svařitelností, a to v závislosti na parametrech tepelného zpracování. Byla použita metalografická analýza pomocí světelného mikroskopu, měření tvrdosti, zkouška tahem a zkouška rázem v ohybu v rozsahu -40 °C až 100 °C. Vzorky byly kaleny z teploty 950 °C a dále popuštěny variantně při teplotách 560 °C, 580 °C a 610 °C. Zjištěné mechanické vlastnosti se výrazně liší od hodnot, které pro tuto ocel uvádí světoví výrobci. Zároveň nebyly v celém rozsahu potvrzeny hodnoty mechanických vlastností oceli G22NiMoCr5-6, jak je uvádí norma SEW 520.The bachelor thesis deals with problematics of casting technology with a focus on the investment casting used in company Kdynium a.s., where the author of this thesis worked during the practice in technology department. An analysis of structure and mechanical properities of the high strenght steel G22NiMoCr5-6 for casting with good weldability, depending on the heat treatment parameters. Metallographic analysis, hardness measurement, tensile test and Charpy impact energy test in the range -40 °C to 100 °C were made. Samples were quenched at 950 °C and variably annealed at 560 °C, 580 °C and 610 °C. The resulting properities are significantly different from the values given by the world producers of this steel. At the same time, mechanical properities of G22NiMoCr5-6 were not confirmed in the full range, as they are shown in the norm SEW 520
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Path-planning Algorithms for Urban Models
No full textTato práce pojednává o globální a lokální navigaci chodců v dynamicky se měnících virtuálních modelech měst. Zvolili jsme jednu existující metodu (D* Lite) ze skupiny existujících heuristických dynamických algoritmů. Pokusili jsme se rychlit přepočet cesty D* Lite za použití lokáních metod. Dále jsme se zaměřili na myšlenku společné cesty, abychom urychlili výpočet nejkratších cest. Toto rozšíření se ukázalo jako velmi cenné a smysluplné.ObhájenoThis thesis deals with global and local navigation of pedestrians in dynamicaly changing virtual city models. We chose one method (D* Lite) from the group of existing heuristic dynamic algorithms. We tried to decrese the computational time of D* Lite path replanning by using local methods. We also focused on a unified way to speed up calculation of shortest paths. This expansion proved to be very valuable and meaningful
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Navigation of individuals in a crowd
No full textBakalářská práce je zaměřena na problematiku hledání cesty chodce ve virtuálním městě. Obsahuje testování čtyř metod (A* algoritmus, Floyd-Warshallův algoritmus, navigačního graf a buněčný a portálový graf) pro hledání nejkratší cesty. Tyto metody modifikujeme, aby hledaly cestu podle priorit chodců, a na závěr porovnáme jejich výsledky.Katedra matematikyObhájenoBachelor thesis is focused on path planning of pedestrians in a virtual city. It contains four methods (A * algorithm, Floyd-Warshall algorithm, Navigation graph and Cell and portal graph) for the shortest path searching. We modify these methods to find pedestrian's path by his priority. Finally we compare their results
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