7,102 research outputs found

    On the Complexity of the Mis\`ere Version of Three Games Played on Graphs

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    We investigate the complexity of finding a winning strategy for the mis\`ere version of three games played on graphs : two variants of the game NimG\text{NimG}, introduced by Stockmann in 2004 and the game Vertex Geography\text{Vertex Geography} on both directed and undirected graphs. We show that on general graphs those three games are PSPACE\text{PSPACE}-Hard or Complete. For one PSPACE\text{PSPACE}-Hard variant of NimG\text{NimG}, we find an algorithm to compute an effective winning strategy in time O(V(G).E(G))\mathcal{O}(\sqrt{|V(G)|}.|E(G)|) when GG is a bipartite graph

    Evaluating Rapid Application Development with Python for Heterogeneous Processor-based FPGAs

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    As modern FPGAs evolve to include more het- erogeneous processing elements, such as ARM cores, it makes sense to consider these devices as processors first and FPGA accelerators second. As such, the conventional FPGA develop- ment environment must also adapt to support more software- like programming functionality. While high-level synthesis tools can help reduce FPGA development time, there still remains a large expertise gap in order to realize highly performing implementations. At a system-level the skill set necessary to integrate multiple custom IP hardware cores, interconnects, memory interfaces, and now heterogeneous processing elements is complex. Rather than drive FPGA development from the hardware up, we consider the impact of leveraging Python to ac- celerate application development. Python offers highly optimized libraries from an incredibly large developer community, yet is limited to the performance of the hardware system. In this work we evaluate the impact of using PYNQ, a Python development environment for application development on the Xilinx Zynq devices, the performance implications, and bottlenecks associated with it. We compare our results against existing C-based and hand-coded implementations to better understand if Python can be the glue that binds together software and hardware developers.Comment: To appear in 2017 IEEE 25th Annual International Symposium on Field-Programmable Custom Computing Machines (FCCM'17

    Krull-Schmidt categories and projective covers

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    Krull-Schmidt categories are additive categories such that each object decomposes into a finite direct sum of indecomposable objects having local endomorphism rings. We provide a self-contained introduction which is based on the concept of a projective cover

    Isotropically polarized speckle patterns

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    The polarization of the light scattered by an optically dense, random solution of dielectric nanoparticles shows peculiar properties when the scatterers exhibit strong electric and magnetic polarizabilities. While the distribution of the scattering intensity in these systems shows the typical irregular speckle patterns, the helicity of the incident light can be fully conserved when the electric and magnetic polarizabilities of the scatterers are equal. We show that the multiple scattering of helical beams by a random dispersion of "dual" dipolar nano-spheres leads to a speckle pattern exhibiting a perfect isotropic constant polarization, a situation that could be useful in coherent control of light as well as in lasing in random media.Comment: 5 pages, 3 figure

    Patenting rationales of academic entrepreneurs in weak and strong organizational regimes

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    This study explores why academic entrepreneurs seek patents for spin-off technology in weak organizational regimes (the employee owns her inventions) and strong organizational regimes (the employer, i.e. the university or research organization, owns these inventions). Specifically, we examine organizational and founding team characteristics as alternative explanations. Matched data of academic spin-offs from both contexts combined with patent data show that founding team characteristics (expert knowledge and entrepreneurial orientation) matter in weak, but not strong regimes. In contrast, organizational patenting norms are the key driver of patenting in strong, but not weak regimes. We discuss the implications of our results for the current literature and technology transfer policies

    Elements Matter: New Relationalities in Colonial Modernity

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    This contribution takes into focus elements as scenes of thought in order to contest our colonial, anthropocentric and extractivist mo-dernity: fires of burning fossil fuels, waves of the open sea, shores as the landscape of islands, clouds in the sky and beyond. We sug-gest that these motifs bear the possibility to examine the problems of our present as well as to develop other, differing and new rela-tionalities

    Characterizing the continuum in Narrow Line Seyfert 1 galaxies

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    Fil: Oio, Gabriel. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Vega Neme, Luis. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Ferreiro, Diego. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Ferreiro, Diego. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Abstract: Narrow Line Seyfert 1 (NLS1) active galactic nuclei (AGN) are a subclass of AGN with Seyfert 1 characteristics but without prominent broad lines. In this work we approach the determination of the non-stellar continuum using the spectral synthesis technique. We chose a sample of 130 NLS1 available in the Sloan Digital Sky Survey (SDSS). This sample comprehend all the objects of such class catalogued on the local universe (z<0.1). With this method we determined (a) central black hole masses, (b) accretion rates, (c) electronic densities in the narrow line region. We found and analyzed possible relations between this parameters.http://adsabs.harvard.edu/abs/2014RMxAC..44..194OpublishedVersionAstronomía (incluye Astrofísica y Ciencias del Espacio

    Estrutura da taxocenose de rapinantes em ambiente de restinga no Sul do Brasil

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    Trabalho de Conclusão de Curso, apresentado para obtenção do Grau de Bacharel, no Curso de Ciências Biológicas da Universidade do Extremo Sul Catarinense, UNESC.Os Cathartiformes, Accipitriformes, Strigiformes e Falconiformes formam o grupo denominado de rapinantes e por ocuparem o topo de cadeias alimentares são consideradas boas indicadoras da qualidade ambiental. A fragmentação e a perda de habitat têm forte impacto sobra a distribuição, abundância e diversidade de rapinantes, prejudicando principalmente as espécies florestais. Na Mata Atlântica ocorrem ao menos 74 espécies de rapinantes, dais quais, 44 são florestais, 30 de ambientes abertos e oito são endêmicas do bioma. Em Santa Catarina, das 68 espécies de aves de rapina que têm registros confirmados, 50 são diurnas. A baixa abundância dos rapinantes na natureza dificulta a realização estudos, tornando-os escassos. Este estudo teve por objetivo analisar a estrutura da taxocenose de rapinantes diurnos na estação quente do ano, em um gradiente de paisagem rural-urbana, em ambiente de restinga na planície costeira sul catarinense. As amostragens foram realizadas mensalmente no período de outubro de 2017 a março de 2018, em uma transecção de 20 km dividida em duas partes (Área Norte e Área Sul), em função do tipo de cobertura e uso da terra e da distância da praia. A transecção foi percorrida de carro a velocidade de 15 a 20 km/h por dois pesquisadores. Todo rapinante avistado foi observado pelo tempo de 15 minutos e seu comportamento foi registrado. Durante este tempo, a nenhum outro rapinante foi dada atenção, exceto para o espécime alvo e os dados dos demais espécimes presentes foram contabilizados apenas para efeitos de riqueza e abundância. Os dados foram analisados em relação a riqueza, abundância, composição em espécies, diversidade, comportamento e uso do espaço. Com o esforço amostral de 120 km, percorridos em seis campanhas, foram obtidos 157 contatos de 10 espécies, pertencentes a nove gêneros e a quatro famílias. Falconidae (n = 4) e Accipitridae (n = 3) foram as mais ricas. Milvago chimango, Athene cunicularia e Falco sparverius foram as espécies mais frequentes e abundantes. A área Sul, caracterizada como área rural e com maior cobertura vegetal florestal, apresentou maior riqueza e número de espécies exclusivas em relação à área Norte, caracterizada como restinga herbáceo-arbustiva, com a presença de aglomerados urbanos. Oito tipos de comportamentos/atividades executados pelos rapinantes foram registrados, sendo forrageio, voo e descanso os mais frequentes, enquanto que alloprening e termorregulação os menos observados. Foi registrado em Athene cunicularia comportamento atípico para a espécie de forrageio por peneiramento, porém, este comportamento ocorreu apenas quando F. sparverius estava presente e executando-o. Os encontros agonísticos, embora não tenham sido muito frequentes, foram relativamente comuns, muitos dos quais, ocorreram entre os rapinantes e espécies não rapinantes. O estudo propiciou o acesso a dados importantes sobre os rapinantes que exploram a planície costeira sul catarinense, assim como, contribuiu para o preenchimento de lacunas importantes para subsidiar ações de conservação deste importante grupo de aves
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