78,174 research outputs found

    Magnetically operated limit switch has improved reliability, minimizes arcing

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    Limit switch for reliable, low-travel, snap action with negligible arcing uses an electrically nonconductive permanent magnet consisting of a ferrimagnetic ceramic and ferromagnetic pole shoes which form a magnetic and electrically conductive circuit with a ferrous-metal armature

    Logos I - Philosophy and the Nature of Morality: The Abolition of Man, C.S. Lewis

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    C.S. Lewis’ objective stance on ethics is argued to be superior to the moral sentimentalism of David Hume, because if there is not agreement on what constitutes moral action, then there is no basis for argument over the existence of moral law

    Thin fillers in the cubical nerves of omega-categories

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    It is shown that the cubical nerve of a strict omega-category is a sequence of sets with cubical face operations and distinguished subclasses of thin elements satisfying certain thin filler conditions. It is also shown that a sequence of this type is the cubical nerve of a strict omega-category unique up to isomorphism; the cubical nerve functor is therefore an equivalence of categories. The sequences of sets involved are in effect the analogues of cubical T-complexes appropriate for strict omega-categories. Degeneracies are not required in the definition of these sequences, but can in fact be constructed as thin fillers. The proof of the thin filler conditions uses chain complexes and chain homotopies.Comment: Revised version to appear in Theory and Applications of Categories; changed terminology; additional figures, examples and references; 27 page

    Bots vs. Wikipedians, Anons vs. Logged-Ins

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    Wikipedia is a global crowdsourced encyclopedia that at time of writing is available in 287 languages. Wikidata is a likewise global crowdsourced knowledge base that provides shared facts to be used by Wikipedias. In the context of this research, we have developed an application and an underlying Application Programming Interface (API) capable of monitoring realtime edit activity of all language versions of Wikipedia and Wikidata. This application allows us to easily analyze edits in order to answer questions such as "Bots vs. Wikipedians, who edits more?", "Which is the most anonymously edited Wikipedia?", or "Who are the bots and what do they edit?". To the best of our knowledge, this is the first time such an analysis could be done in realtime for Wikidata and for really all Wikipedias--large and small. Our application is available publicly online at the URL http://wikipedia-edits.herokuapp.com/, its code has been open-sourced under the Apache 2.0 license.Comment: Poster at the Web Science Track of the 23rd International World Wide Web Conference (WWW2014), Seoul, Kore

    The algebraic structure of the universal complicial sets

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    The nerve of a strict omega-category is a simplicial set with additional structure, making it into a so-called complicial set, and strict omega-categories are in fact equivalent to complicial sets. The nerve functor is represented by a sequence of strict omega-categories, called orientals, which are associated to simplexes. In this paper we give a detailed algebraic description of the morphisms between orientals. The aim is to describe complicial sets algebraically, by operators and equational axioms.Comment: 25 pages. As to appear in Journal of Pure and Applied Algebra. Minor corrections, addtional explanations, some propositions reclassified as lemma

    A study of the relatioship between job satisfaction and educational preparation

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    Thesis (M.S.)--Boston Universit

    Complicial structures in the nerves of omega-categories

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    It is known that strict omega-categories are equivalent through the nerve functor to complicial sets and to sets with complicial identities. It follows that complicial sets are equivalent to sets with complicial identities. We discuss these equivalences. In particular we give a conceptual proof that the nerves of omega-categories are complicial sets, and a direct proof that complicial sets are sets with complicial identities
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