8,371 research outputs found

    Construction Of A Rich Word Containing Given Two Factors

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    A finite word ww with w=n\vert w\vert=n contains at most n+1n+1 distinct palindromic factors. If the bound n+1n+1 is attained, the word ww is called \emph{rich}. Let \Factor(w) be the set of factors of the word ww. It is known that there are pairs of rich words that cannot be factors of a common rich word. However it is an open question how to decide for a given pair of rich words u,vu,v if there is a rich word ww such that \{u,v\}\subseteq \Factor(w). We present a response to this open question:\\ If w1,w2,ww_1, w_2,w are rich words, m=max{w1,w2}m=\max{\{\vert w_1\vert,\vert w_2\vert\}}, and \{w_1,w_2\}\subseteq \Factor(w) then there exists also a rich word wˉ\bar w such that \{w_1,w_2\}\subseteq \Factor(\bar w) and wˉm2k(m)+2\vert \bar w\vert\leq m2^{k(m)+2}, where k(m)=(q+1)m2(4q10m)log2mk(m)=(q+1)m^2(4q^{10}m)^{\log_2{m}} and qq is the size of the alphabet. Hence it is enough to check all rich words of length equal or lower to m2k(m)+2m2^{k(m)+2} in order to decide if there is a rich word containing factors w1,w2w_1,w_2

    Retrosplenial Cortex and Long-Term Memory: Molecules to Behavior

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    The retrosplenial cortex (RSC) is reciprocally connected with the hippocampus and various parahippocampal cortical regions, suggesting that RSC is well-positioned to contribute to hippocampal-dependent memory. Consistent with this, substantial behavioral evidence indicates that RSC is essential for consolidating and/or retrieving contextual and spatial memories. In addition, there is growing evidence that RSC neurons undergo activity-dependent plastic changes during memory formation and retrieval. In this paper we review both the behavioral and cellular/molecular data and posit that the RSC has a particularly important role in the storage and retrieval of spatial and contextual memories perhaps due its involvement in binding together multiple cues in the environment. We identify remaining questions and avenues for future research that take advantage of emerging methods to selectively manipulate RSC neurons both spatially and temporally and to image the RSC in awake, behaving animals

    A study of environmental characterization of conventional and advanced aluminum alloys for selection and design. Phase 2: The breaking load test method

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    A technique is demonstrated for accelerated stress corrosion testing of high strength aluminum alloys. The method offers better precision and shorter exposure times than traditional pass fail procedures. The approach uses data from tension tests performed on replicate groups of smooth specimens after various lengths of exposure to static stress. The breaking strength measures degradation in the test specimen load carrying ability due to the environmental attack. Analysis of breaking load data by extreme value statistics enables the calculation of survival probabilities and a statistically defined threshold stress applicable to the specific test conditions. A fracture mechanics model is given which quantifies depth of attack in the stress corroded specimen by an effective flaw size calculated from the breaking stress and the material strength and fracture toughness properties. Comparisons are made with experimental results from three tempers of 7075 alloy plate tested by the breaking load method and by traditional tests of statistically loaded smooth tension bars and conventional precracked specimens

    On the Number of Closed Factors in a Word

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    A closed word (a.k.a. periodic-like word or complete first return) is a word whose longest border does not have internal occurrences, or, equivalently, whose longest repeated prefix is not right special. We investigate the structure of closed factors of words. We show that a word of length nn contains at least n+1n+1 distinct closed factors, and characterize those words having exactly n+1n+1 closed factors. Furthermore, we show that a word of length nn can contain Θ(n2)\Theta(n^{2}) many distinct closed factors.Comment: Accepted to LATA 201

    Invariance: a Theoretical Approach for Coding Sets of Words Modulo Literal (Anti)Morphisms

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    Let AA be a finite or countable alphabet and let θ\theta be literal (anti)morphism onto AA^* (by definition, such a correspondence is determinated by a permutation of the alphabet). This paper deals with sets which are invariant under θ\theta (θ\theta-invariant for short).We establish an extension of the famous defect theorem. Moreover, we prove that for the so-called thin θ\theta-invariant codes, maximality and completeness are two equivalent notions. We prove that a similar property holds in the framework of some special families of θ\theta-invariant codes such as prefix (bifix) codes, codes with a finite deciphering delay, uniformly synchronized codes and circular codes. For a special class of involutive antimorphisms, we prove that any regular θ\theta-invariant code may be embedded into a complete one.Comment: To appear in Acts of WORDS 201

    Radon mitigation during the installation of the CUORE 0νββ0\nu\beta\beta decay detector

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    CUORE - the Cryogenic Underground Observatory for Rare Events - is an experiment searching for the neutrinoless double-beta (0νββ0\nu\beta\beta) decay of 130^{130}Te with an array of 988 TeO2_2 crystals operated as bolometers at \sim10 mK in a large dilution refrigerator. With this detector, we aim for a 130^{130}Te 0νββ0\nu\beta\beta decay half-life sensitivity of 9×10259\times10^{25} y with 5 y of live time, and a background index of 102\lesssim 10^{-2} counts/keV/kg/y. Making an effort to maintain radiopurity by minimizing the bolometers' exposure to radon gas during their installation in the cryostat, we perform all operations inside a dedicated cleanroom environment with a controlled radon-reduced atmosphere. In this paper, we discuss the design and performance of the CUORE Radon Abatement System and cleanroom, as well as a system to monitor the radon level in real time.Comment: 10 pages, 6 figures, 1 tabl

    Deterministic Multi-sensor Measurement-adaptive Birth using Labeled Random Finite Sets

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    Measurement-adaptive track initiation remains a critical design requirement of many practical multi-target tracking systems. For labeled random finite sets multi-object filters, prior work has been established to construct a labeled multi-object birth density using measurements from multiple sensors. A truncation procedure has also been provided that leverages a stochastic Gibbs sampler to truncate the birth density for scalability. In this work, we introduce a deterministic herded Gibbs sampling truncation solution for efficient multi-sensor adaptive track initialization. Removing the stochastic behavior of the track initialization procedure without impacting average tracking performance enables a more robust tracking solution more suitable for safety-critical applications. Simulation results for linear sensing scenarios are provided to verify performance.Comment: Accepted to the 2023 Proc. IEEE 26th Int. Conf. Inf. Fusio
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