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4. Semihypergroup-Based Graph for Modeling International Spread of COVID-n in Social SystemsNarjes Firouzkouhi, Reza Ameri, Abbas Amini, Hashem Bordbar, 2022, original scientific article Abstract: Graph theoretic techniques have been widely applied to model many types of links in social systems. Also, algebraic hypercompositional structure theory has demonstrated its systematic
application in some problems. Influenced by these mathematical notions, a novel semihypergroup based graph (SBG) of G = hH, Ei is constructed through the fundamental relation gn on H, where semihypergroup H is appointed as the set of vertices and E is addressed as the set of edges on SBG. Indeed, two arbitrary vertices x and y are adjacent if xgny. The connectivity of graph G is characterized by xg y, whereby the connected components SBG of G would be exactly the elements of the fundamental group H/g . Based on SBG, some fundamental characteristics of the graph such as complete, regular, Eulerian, isomorphism, and Cartesian products are discussed along with illustrative examples to clarify the relevance between semihypergroup H and its corresponding graph. Furthermore, the notions of geometric space, block, polygonal, and connected components are introduced in terms of the developed SBG. To formulate the links among individuals/countries in
the wake of the COVID (coronavirus disease) pandemic, a theoretical SBG methodology is presented to analyze and simplify such social systems. Finally, the developed SBG is used to model the trend diffusion of the viral disease COVID-n in social systems (i.e., countries and individuals). Keywords: graph theory, hypergroup, fundamental relation, social systems, geometric space Published in RUNG: 23.11.2022; Views: 955; Downloads: 0 This document has many files! More... |
5. Cluster-lensed supernovae with the Roman Space Telescope and Vera Rubin observatoryMateusz Bronikowski, Tanja Petrushevska, Justin Pierel, 2022, published scientific conference contribution abstract Abstract: I will present our current efforts to enable the use of strongly lensed supernovae behind galaxy clusters as powerful tools to tackle several open questions in astrophysics and cosmology. As a preparatory task, we are collecting all available gravitational telescopes into a database, and estimating the properties of all reported multiply-imaged galaxies behind clusters. We are building a tool that will enable accurate estimates of cluster-lensed supernova yields for a given survey. In addition, we are developing the methods to extract the cosmological parameters from cluster-lensed supernovae in the Rubin and Roman data. Keywords: supernova, gravitational lensing, Vera Rubin Observatory, Roman Space telescope, LSST, Hubble constant Published in RUNG: 09.11.2022; Views: 976; Downloads: 5 Link to full text This document has many files! More... |
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7. Caristi-Kirk and Oettli-Théra ball spaces and applicationsPiotr Błaszkiewicz, Hanna Ćmiel, Alessandro Linzi, Piotr Szewczyk, 2019, original scientific article Keywords: Metric space, ball space, Christi-Kirk fixed point theorem, Ekeland's variational principle, Oettli-Théra theorem, Takahashi's theorem, flower petal theorem Published in RUNG: 26.09.2022; Views: 906; Downloads: 0 This document has many files! More... |
8. Categorical Perception of a vowel contrast in native speakers and second language learners.Alessandra Zappoli, 2022, published scientific conference contribution abstract Abstract: The perceptual space of a speaker is shaped in infancy according to the phonological inventory of the L1. Phonological categories correlate with Categorical Perception (CP) and Perceptual Magnet (PM) effects, lowering the discrimination rate between the same category’s sounds and increasing it at the Category Boundaries (Liberman et al., 1967; Kuhl et al., 1992).
Second Language (L2) learning in adulthood requires creating new categories, some overlapping with the existing ones. When L2 and L1 categories overlap, the PM and CP effects might block the creation of the target L2 sounds, linked to Foreign Accented speech.
In this study, I investigate with the CP paradigm, the categorization, and discrimination of two German words: ʃɔːn] (‘already’) vs. [ʃøːn] (‘beautiful’) distinguished by a vowel contrast existing in German but not in Italian. I tested: i) 20 L1 speakers of German (L1); 34 L2 learners of German, L1 speakers of Italian – ii) 14 exposed to native speech (Tandem); iii) 18 not exposed to it; iv) 20 L1 speakers of Italian (Naïve). The oddball discrimination task presented the stimuli in 6 orders: AAB, ABA, ABB, BAA, BAB, BBA. L2 learners performed the LEXTALE in German (Lemhöfer & Broersma, 2012).
Results show that the categorization and discrimination performance linearly increase with language proficiency. Categorization only correlates with LEXTALE. Exposure to native speech is relevant. The presence of CP - as classically reported in the literature - is affected by the order of presentation of the stimuli in the oddball paradigm, emerging with BAB, ABA, BBA orders. Keywords: vowel categorization, speech categorization, naive listeners, native speakers, L2 learners, categorical perception paradigm, perceptual space Published in RUNG: 30.08.2022; Views: 1188; Downloads: 0 This document has many files! More... |
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