Design of a Band Saw (a Cutter)

Import 26/06/2013Práce se zabývá konstrukčním návrhem pily pro pořez kmenů do průměru 300 mm a délky 6 m. Obsahuje rešerši stávajících zařízení pro pořez kmenů s obecným rozdělením těchto strojů a uvedením zařízení pro údržbu jejich nástroje. Dále zvolení konkrétní konstrukce pro další zpracování. V hlavní části se pak nachází výpočet řezné síly, volba hnacího elektromotoru a volba konstrukce pro nastavení výšky řezu. Pila je schopna vyřezat ze zadaného kmene řezivo jakýchkoliv libovolných rozměrů. Výsledkem práce je konstrukční dokumentace pro výrobu pily.The work deals with the structural design of saws for cutting logs up to 300 mm and a length of 6 m. Contains a search of existing facilities for cutting logs with a general distribution of these machines and the equipment for maintenance of their tools. Furthermore, selecting a specific construction for further processing. The main section of project is calculating the cutting forces, the choice of the drive motor and the choice of design for the height adjustment for tool. The saw is able to cut timber from the specified trunk of any arbitrary size. The result is design documentation for production saws.Prezenční347 - Katedra částí a mechanismů strojůvelmi dobř

Compact Argumentation Frameworks

Abstract argumentation frameworks (AFs) are one of the most studied formalisms in AI. In this work, we introduce a certain subclass of AFs which we call compact. Given an extension-based semantics, the corresponding compact AFs are characterized by the feature that each argument of the AF occurs in at least one extension. This not only guarantees a certain notion of fairness; compact AFs are thus also minimal in the sense that no argument can be removed without changing the outcome. We address the following questions in the paper: (1) How are the classes of compact AFs related for different semantics? (2) Under which circumstances can AFs be transformed into equivalent compact ones? (3) Finally, we show that compact AFs are indeed a non-trivial subclass, since the verification problem remains coNP-hard for certain semantics.Comment: Contribution to the 15th International Workshop on Non-Monotonic Reasoning, 2014, Vienn

Assessment of physical habitat modification in the Bílina River Basin

The improvement of the ecological status of many heavily modified water bodies in Europe is a priority of the EuropeanWater Framework Directive. This paper evaluates the physical river habitat quality of the B'ılina River, one of the most polluted and heavily modified rivers in Central Europe that is mainly classified as a heavily modified WB. The physical river habitat was evaluated using the Ecomorphological River Habitat method (EcoRivHab) and the LAWA Overview Survey method (LAWA-OS). The EcoRivHab method uses field surveys as data input in which the hydromorphological status is determined by 31 parameters, while LAWA-OS is based on the assessment of 17 parameters using available data and mapping resources. Human activities that affect the B'ılina River are primarily the expanding coal mining operation and chemical industry, which negatively influence physical river habitat condition. The majority of the reaches of the B'ılina River have become embedded, straightened and reinforced, with almost no natural vegetation in the riparian zone. Based on the results of this study, the B'ılina catchment was identified as having a strong anthropogenic impact, primarily due to the high amount of reaches in ecological class (EC) IV (20.5 % EcoRivHab; 34 % LAWA-OS) and V (27.8 % EcoRivHab; 29 % LAWA-OS). These reaches were located in urban and mining areas. Significantly lower proportions of reaches were classified in EC I (2.5 % EcoRivHab; 7.5 % LAWA-OS) and II (9.5 % EcoRivHab; 7 % LAWA-OS), which are located on the upper course of the B'ılina River. Differences between methods in the hydromorphological evaluations are caused by a variety of observed parameters, including different delimitations of river zones and widths of the scoring intervals. This study demonstrated the possibility of applying both methods in assessing heavily modified and artificial water bodies.La mejora del estado ecol'ogico de muchas masas de agua muy modificadas en Europa es una petición de la Directiva Marco del Agua-DMA. En este trabajo se evalúa la calidad del hábitat físico del río Bílina, uno de los ríos más contaminados y modificadas, en Europa Central, el cuál ha sido clasificado como un cuerpo de agua muy modificado. El hábitat del río Bílina se evaluó mediante el método "Ecomorphological River Habitat" (EcoRivHab) y el m'etodo "LAWA Overview Survey method" (LAWA-OS). El método EcoRivHab utiliza datos de muestreo sobre el terreno y el estado hidromorfológico se determina mediante 31 parámetros, mientras que LAWA-OS se basa en la evaluación de 17 parámetros utilizando los datos disponibles y la asignación de recursos. La actividad humana en el río Bílina está representada sobre todo por la expansión de la industria minera del carbón y química que influyen negativamente en la condición física del hábitat fluvial. La mayoría de los tramos del río Bílina se han dragado, enderezado y reforzado quedando muy poca vegetación natural en la zona ribereña. En base a los resultados obtenidos, es posible identificar la cuenca del río Bílina con un fuerte impacto antropogénico, principalmente debido a la gran cantidad de tramos en la clase ecológica (CE), IV (20.5 % EcoRivHab; 34 % LAWA-OS) y la CE V (27.8 % EcoRivHab y el 29 % de LAWA-OS). Estos tramos fluviales estaban principalmente ubicados en zonas urbanas y mineras. Una cantidad significativamente menor se clasificaron dentro de la CE I (2.5 % EcoRivHab; 7.5 % LAWA-OS) y CE II (9.5 % EcoRivHab; 7 % LAWA-OS), encontrándose estos en el curso superior del río Bílina. Las diferencias en los resultados de la evaluación hidromorfológica entre los métodos utilizados son causadas por una variedad de parámetros observados, la delimitación de las diferentes zonas del río y la amplitud de los intervalos de puntuación. El estudio demostró la posibilidad de aplicar ambos métodos para evaluar cuerpos de agua muy modificados y artificiales

Symphony nº. 4 in G major : (op. 88) /

Orgánico: 2[1.2/pic] 2[1.2/Eh] 2 2 -- 4 2 3 1 -- tmp -- strDuración: 34; duraciones movs.: 9 10 6 9Copia digital. España : Ministerio de Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, s2021Tít. de la carp.: `Cuarta sinfonía [Octaba sinfonía]`Partes: Fl 1, 2/Pic, Ob 1, 2/Eh, Cl 1, 2, Bn 1, 2, Hn 1, 2, 3, 4, Tp 1, 2, Tbn 1, 2, 3, Tuba, Tmp, Vn 1 (9), Vn 2 (8), Va (6), Vc (5), Db (4

Welfare maximization with friends-of-friends network externalities

Online social networks allow the collection of large amounts of data about the influence between users connected by a friendship-like relationship. When distributing items among agents forming a social network, this information allows us to exploit network externalities that each agent receives from his neighbors that get the same item. In this paper we consider Friends-of-Friends (2-hop) network externalities, i.e., externalities that not only depend on the neighbors that get the same item but also on neighbors of neighbors. For these externalities we study a setting where multiple different items are assigned to unit-demand agents. Specifically, we study the problem of welfare maximization under different types of externality functions. Let n be the number of agents and m be the number of items. Our contributions are the following: (1) We show that welfare maximization is APX-hard; we show that even for step functions with 2-hop (and also with 1-hop) externalities it is NP-hard to approximate social welfare better than (1-1/e). (2) On the positive side we present (i) an O(sqrt n)-approximation algorithm for general concave externality functions, (ii) an O(\log m)-approximation algorithm for linear externality functions, and (iii) an (1-1/e)\frac{1}{6}-approximation algorithm for 2-hop step function externalities. We also improve the result from [6] for 1-hop step function externalities by giving a (1-1/e)/2-approximation algorithm

Improved set-based symbolic algorithms for parity games

Graph games with omega-regular winning conditions provide a mathematical framework to analyze a wide range of problems in the analysis of reactive systems and programs (such as the synthesis of reactive systems, program repair, and the verification of branching time properties). Parity conditions are canonical forms to specify omega-regular winning conditions. Graph games with parity conditions are equivalent to mu-calculus model checking, and thus a very important algorithmic problem. Symbolic algorithms are of great significance because they provide scalable algorithms for the analysis of large finite-state systems, as well as algorithms for the analysis of infinite-state systems with finite quotient. A set-based symbolic algorithm uses the basic set operations and the one-step predecessor operators. We consider graph games with n vertices and parity conditions with c priorities (equivalently, a mu-calculus formula with c alternations of least and greatest fixed points). While many explicit algorithms exist for graph games with parity conditions, for set-based symbolic algorithms there are only two algorithms (notice that we use space to refer to the number of sets stored by a symbolic algorithm): (a) the basic algorithm that requires O(n^c) symbolic operations and linear space; and (b) an improved algorithm that requires O(n^{c/2+1}) symbolic operations but also O(n^{c/2+1}) space (i.e., exponential space). In this work we present two set-based symbolic algorithms for parity games: (a) our first algorithm requires O(n^{c/2+1}) symbolic operations and only requires linear space; and (b) developing on our first algorithm, we present an algorithm that requires O(n^{c/3+1}) symbolic operations and only linear space. We also present the first linear space set-based symbolic algorithm for parity games that requires at most a sub-exponential number of symbolic operations

The Complexity of Repairing, Adjusting, and Aggregating of Extensions in Abstract Argumentation

We study the computational complexity of problems that arise in abstract argumentation in the context of dynamic argumentation, minimal change, and aggregation. In particular, we consider the following problems where always an argumentation framework F and a small positive integer k are given. - The Repair problem asks whether a given set of arguments can be modified into an extension by at most k elementary changes (i.e., the extension is of distance k from the given set). - The Adjust problem asks whether a given extension can be modified by at most k elementary changes into an extension that contains a specified argument. - The Center problem asks whether, given two extensions of distance k, whether there is a "center" extension that is a distance at most (k-1) from both given extensions. We study these problems in the framework of parameterized complexity, and take the distance k as the parameter. Our results covers several different semantics, including admissible, complete, preferred, semi-stable and stable semantics