460 research outputs found

    Normal, Abby Normal, Prefix Normal

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    A prefix normal word is a binary word with the property that no substring has more 1s than the prefix of the same length. This class of words is important in the context of binary jumbled pattern matching. In this paper we present results about the number pnw(n)pnw(n) of prefix normal words of length nn, showing that pnw(n)=Ω(2ncnlnn)pnw(n) =\Omega\left(2^{n - c\sqrt{n\ln n}}\right) for some cc and pnw(n)=O(2n(lnn)2n)pnw(n) = O \left(\frac{2^n (\ln n)^2}{n}\right). We introduce efficient algorithms for testing the prefix normal property and a "mechanical algorithm" for computing prefix normal forms. We also include games which can be played with prefix normal words. In these games Alice wishes to stay normal but Bob wants to drive her "abnormal" -- we discuss which parameter settings allow Alice to succeed.Comment: Accepted at FUN '1

    Fast branching algorithm for Cluster Vertex Deletion

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    In the family of clustering problems, we are given a set of objects (vertices of the graph), together with some observed pairwise similarities (edges). The goal is to identify clusters of similar objects by slightly modifying the graph to obtain a cluster graph (disjoint union of cliques). Hueffner et al. [Theory Comput. Syst. 2010] initiated the parameterized study of Cluster Vertex Deletion, where the allowed modification is vertex deletion, and presented an elegant O(2^k * k^9 + n * m)-time fixed-parameter algorithm, parameterized by the solution size. In our work, we pick up this line of research and present an O(1.9102^k * (n + m))-time branching algorithm

    Оборудование для испытания листовых конструкционных материалов при двухосном растяжении. Сообщение 2. Испытания двухосным нагружением в плоскости листа

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    Рассмотрены конструктивные особенности оборудования для механических испытаний листовых конструкционных материалов в условиях двухосного статического, циклического и динамического нагружения. Предложены оригинальные решения проблем, связанных с проведением усталостных испытаний крестообразных образцов без применения сложных гидравлических систем и динамических испытаний с использованием простейших испытательных машин на одноосное растяжение-сжатие.Розглянуто конструктивні особливості устаткування для механічних випробувань листових конструкційних матеріалів в умовах двовісного статичного, циклічного та динамічного навантаження. Запропоновано оригінальні розв’язки ряду проблем, що пов’язані з використанням хрестоподібних зразків для випробувань на втому без застосування складних гідравлічних систем та для динамічних випробувань за допомогою найпростіших випробувальних машин на одновісний розтяг-стиск.Original methods of mechanical testing of sheet materials under conditions of biaxial static, cyclic, and dynamic loading are described. Solutions were suggested for a number of problems related to the use of cruciform specimens in fatigue tests without employment of complex hydraulic systems and in dynamic tests in uniaxial tension-compression using mechanical testing machines

    Making Space, Making Place: Digital Togetherness and the Redefinition of Migrant Identities Online

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    Immigrants have played a fundamental role in shaping the life and form of urban public spaces for generations. Their efforts, as many scholars have observed, mostly aimed at creating places of comfort in new and sometimes hostile receiving countries. In recent years, the combined contribution of the built environment and screen-based experiences have shaped migrants’ sense of community and belonging, thus making the concept of online community central to ideas about space and public life. Drawing upon a 3-year online ethnography, the article discusses to what extent new media constitute spaces of digital togetherness, where diasporic experiences and transnational identities are constructed and negotiated. It presents a transnational model of creative media consumption, which helps give insight as to how diasporas and ethnic minorities contribute to the transformation of public space in the Digital Age

    New Economy, Food, and Agriculture

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    Consumers are becoming increasingly more informed about food systems and are interested not only in healthy, safe, and tasty food but also sustainable production, animal welfare, climate changes, and food waste. Consumers are also more focused on changing their lifestyle related to improved health knowledge and nutrition education (Timmer 2005). Maxwell and Slater (2004) have proposed criteria to evaluate food systems, including nutrition and health, rights and influence, security, sustainability, equality, and social inclusion. The authors also point out that the primary international institutions in the food value chain are not only the Food and Agriculture Organization and World Health Organization but also United Nations Industrial Development Organization, International Labour Organization, and World Trade Organization. The emerging trends in the food system are features of the {\dq}new economy.{\dq} This term describes the outcome of the transition from production- and manufacturing-based economy to a service-based or post-industrial economy at the end of the twentieth century. The traditional production factors such as cheap labor, land, and raw materials lose their importance in generating profits and competitiveness. The key is understanding of food consumer demand, knowledge of food industry and agriculture employees based on creativity, and flexibility of processes of production

    New Economy, Food, and Agriculture

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    Consumers are becoming increasingly more informed about food systems and are interested not only in healthy, safe, and tasty food but also sustainable production, animal welfare, climate changes, and food waste. Consumers are also more focused on changing their lifestyle related to improved health knowledge and nutrition education (Timmer 2005). Maxwell and Slater (2004) have proposed criteria to evaluate food systems, including nutrition and health, rights and influence, security, sustainability, equality, and social inclusion. The authors also point out that the primary international institutions in the food value chain are not only the Food and Agriculture Organization and World Health Organization but also United Nations Industrial Development Organization, International Labour Organization, and World Trade Organization. The emerging trends in the food system are features of the {\dq}new economy.{\dq} This term describes the outcome of the transition from production- and manufacturing-based economy to a service-based or post-industrial economy at the end of the twentieth century. The traditional production factors such as cheap labor, land, and raw materials lose their importance in generating profits and competitiveness. The key is understanding of food consumer demand, knowledge of food industry and agriculture employees based on creativity, and flexibility of processes of production
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