72 research outputs found

    Network Capacity Bound for Personalized PageRank in Multimodal Networks

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    In a former paper the concept of Bipartite PageRank was introduced and a theorem on the limit of authority flowing between nodes for personalized PageRank has been generalized. In this paper we want to extend those results to multimodal networks. In particular we introduce a hypergraph type that may be used for describing multimodal network where a hyperlink connects nodes from each of the modalities. We introduce a generalisation of PageRank for such graphs and define the respective random walk model that can be used for computations. we finally state and prove theorems on the limit of outflow of authority for cases where individual modalities have identical and distinct damping factors.Comment: 28 pages. arXiv admin note: text overlap with arXiv:1702.0373

    MICROSTRUCTURE OF THE DIFFUSION LAYER OBTAINED IN Ti6Al2Cr2Mo ALLOY DURING GLOW DISCHARGE NITRIDING

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    ABSTRACT This paper presents the results of metallographic, X-ray, and TEM examinations of the microstructure and the sub-structure of the diffusion layer that underlies the TiN + Ti 2 N layer produced by glow discharge nitriding of the Ti6Al2Cr2Mo alloy. The metallographic examinations show that a two-phase zone α + β -its thickness increasing with the increasing process temperature -can be observed underneath the nitride layer after half an hour of nitriding at 940 o C, when the core of the sample has an α−phase structure. The presence of the glow discharge assisting the nitriding process accelerated the thickening of both the nitride zone and the diffusion layer. Morphology of α−phase grains changed as well. The grain lengh-to-thickness ratio decreased. X-ray examinations revealed the presence in the substrate structure of two kinds of solid solution with the α titanium matrix. TEM analysis showed a state of certain ordering of the crystalline lattice and, locally, a tweed-type structure of the β phase

    Biological properties of surface layers for ring of heart valve application

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    Oryginalna sztuczna komora wspomagania serca POLVAD opracowana w Polsce, została zastosowana dotychczas w leczeniu ponad 210 pacjentów. Najdłuższe wspomaganie serca za pomocą komory POLVAD trwało ponad rok. Dla protezy tej opracowywana jest innowacyjna zastawka dyskowa, z nisko profilowym pierścieniem wykonanym ze stopu tytanu. Dla zminimalizowania trombogenności pierścienia zastawki opracowano dyfuzyjne warstwy powierzchniowe: azotowaną typu TiN+Ti2N+αTi(N) i tlenoazotowaną typu TiO2+TiN+Ti2N+αTi(N), wytwarzane obróbką jarzeniową na potencjale plazmy. Trombogenność różnych kompozycji warstw została porównana w aspekcie aktywacji i adhezji płytek krwi do powierzchni biomateriału. Oceniono również wpływ metody sterylizacji biomateriału na intensywność adhezji trombocytów do jego powierzchni. Warstwy TiN oraz TiO2wykazały najniższą trombogenność, przy czym dla warstwy TiN korzystniejsza jest sterylizacja gazowa, podczas gdy dla warstwy TiO2- sterylizacja plazmowa.The original ventricular assist device POLVAD developed in Poland was used in over 210 patients so far. The longest POLVAD heart assistance excided one year. The innovative tilting disk valve with low profile ring made of titanium is developed for POLVAD. To minimize the valve ring thrombogenicity the diffusive surface layers were manufactured: nitriding TiN+Ti2N+αTi(N) and oxynitriding TiO2+TiN+Ti2N+αTi(N), in the glow discharge process on the plasma potential level. The thrombogenicity of different layers compositionwas compared regarding platelets activation and platelets adhesion to the material surface. The influence of material sterilization method on the platelets adhesion intensity was evaluated in addition. The nitriding TiN and oxynitriding TiO2layers have demonstrated the lowest thrombogenicity while the gas sterilization was the most profitable for nitriding layers – TiN and the plasma sterilization for oxynitriding layers – TiO2

    The Confidence Database

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    Understanding how people rate their confidence is critical for the characterization of a wide range of perceptual, memory, motor and cognitive processes. To enable the continued exploration of these processes, we created a large database of confidence studies spanning a broad set of paradigms, participant populations and fields of study. The data from each study are structured in a common, easy-to-use format that can be easily imported and analysed using multiple software packages. Each dataset is accompanied by an explanation regarding the nature of the collected data. At the time of publication, the Confidence Database (which is available at https://osf.io/s46pr/) contained 145 datasets with data from more than 8,700 participants and almost 4 million trials. The database will remain open for new submissions indefinitely and is expected to continue to grow. Here we show the usefulness of this large collection of datasets in four different analyses that provide precise estimations of several foundational confidence-related effects

    An algorithm for finding most likely explanations in valuation based systems

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    A method for finding a number of best explanations in so-called valuation based system is presented. Roughly speaking, the method allows to sort (decreasingly or increasingly) a function of many variables without explicit computation of values of this function. The only condition is that the function be decomposable, i.e. can be expressed as a combination of a number of low-dimensional functions called components. Two cases are considered: the combination operator has an inverse and a more elaborated case when the combination operator has no inverse

    Evolutionary algorithm for learning Bayesian structures from data

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    In this paper we report an evolutionary approach to learning Bayesian networks from data. We explain reasons, which advocate such a non-deterministic approach. We analyze weaknesses of previous works and come to conclusion that we should operate in the search space native for the problem i.e. in the space of directed acyclic graphs instead of standard space of binary strings. This requires adaptation of evolutionary methodology into very specific needs. We propose quite new data representation and implementation of generalized genetic operators and then we present an efficient algorithm capable of learning complex networks without additional assumptions. We discuss results obtained with this algorithm. The approach presented in this paper can be extended with the possibility to absorb some suggestions from experts or obtained by means of data preprocessing

    Rozproszony protokół enumeracji dla systemów z wartościowaniami

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    The paper presents a new algorithm for the problem of an enumeration protocol for nodes in a network. The new algorithm, contrary to previous ones, is local both in information access (neighbourhood only) and information stored (proportional to the number of neighbours). This property is achieved at the expense of the type of connectivity the network is assumed to exhibit.W pracy przedstawiono nowy algorytm enumeracji węzłów sieci. W odróżnieniu od dotychczasowych algorytmów jest on lokalny zarówno w sensie dostępu do informacji (uwzględnia się wyłącznie informacje pochodzące od sąsiadów aktualnie przetwarzanego węzła) jak i przechowywania informacji (ilość informacji jest proporcjonalna do liczby sąsiadów danego węzła). Cechę lokalności uzyskano zawężając rozważania do rodziny grafów triangulowanych, które odgrywają podstawową rolę w teorii sieci bayesowskich. Uogólnieniem tych ostatnich są systemy z wartościowaniami, nazywane też grafowymi systemami ekspertowymi, czyli struktury grafowe służące do reprezentacji niedeterministycznych zależności między zmiennymi (odpowiadają im węzły grafu)
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