cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Coulomb force correction to the decay b -> c anti-c s in the threshold
Creators: name: Hasegawa, K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the physical origins of the $O(alpha_{s})$ and $O(alpha_{s}^{2})$ corrections to the $bar{c}-s$ current in the decay $b -> c bar{c} s$ in the threshold region $delta=(M_{b}-2m_{c})/2M_{b} << 1$. We obtain the corrections which are produced by the Coulomb force between the anti-charm and strange quarks. The Coulomb corrections $C_{F} pi^{2}$ at $O(alpha_{s})$ and $-C_{F}^{2} pi^{2} ln delta$ at $O(alpha_{s}^{2})$ account for 300% and 120% of the corresponding terms in the Abelian-type perturbative corrections respectively. The differences between the Coulomb and perturbative corrections imply that other corrections which have other physical origins exist. We also check that the Wilson coefficient for the anomalous dimension of the $bar{c}-s$ current reproduces the leading and the next-to-leading logarithmic terms in the perturbative corrections.
description: 18 pages, 2 figures, Version to appear in Progress of Theoretical Physics
Η ιστορία των ΓΚΟΥΛΑΓΚ: Αλεξάντρ Σολζενίτσιν-Βαρλάμ Σαλάμοφ
Creators: name: Δρόσου, Κωνσταντίνα Μάνθου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Στρατόπεδα εργασίας
Σταλινική Περίοδος
Λογοτεχνία
GULAGs
Stalinism
Literature

description: Σκοπός της διατριβής ήταν η μελέτη, μέσα από λογοτεχνικά κείμενα (κυρίως ρώσων συγγραφέων), της δημιουργίας των στρατοπέδων εργασίας (ΓΚΟΥΛΑΓΚ) στην Σοβιετική Ρωσία. Αρχικά, γίνεται μια ιστορική προσέγγιση για το πολιτικό σύστημα που δημιούργησε τα στρατόπεδα. Περιγράφονται αναλυτικά τα ιστορικά γεγονότα που συνέβαλαν στην δημιουργία των πρώτων στρατοπέδων συγκέντρωσης/εργασίας και με ποιο τρόπο το «φαινόμενο» των ΓΚΟΥΛΑΓΚ γιγαντώθηκε και επιβίωσε για περισσότερα από 20 χρόνια. Στα κεφάλαια που ακολουθούν, παρουσιάζονται αναλυτικά τα λογοτεχνικά κείμενα των Αλεξάντρ Σολζενίτσιν και Βαρλάμ Σαλάμοφ, «Αρχιπέλαγος ΓΚΟΥΛΑΓΚ» και «Ιστορίες από την Κολιμά» αντίστοιχα. Τα έργα είναι γραμμένα από δύο ρώσους συγγραφείς, επιζώντες των στρατοπέδων. Στα κείμενά τους παρουσιάζουν τον τρόπο διαβίωσης των κρατούμενων (κυρίως πολιτικών) μέσα στα στρατόπεδα ή τις μεταγωγικές φυλακές.
description: The aim of the present thesis was the study of the “creation” of labor camps (GULAG) in Soviet Russia through literature (mainly Russian authors). Initially, the thesis contains a historical approach to the political system that created those camps. An analytical documentation of the historical events that contributed to the creation of the GULAGs is made and how the Gulag "phenomenon" survived for more than 20 years. In the chapters that follow, the works of Aleksandr Solzhenitsyn and Varlam Salamof are presented, which are "The Gulag Archipelago" and "Kolyma Tales” respectively. These works are from two Russian writers who were both labor camp survivors. In their texts, the everyday life of – mostly political - prisoners in the Siberian camps is shown.
Earth may be a planet that has been born in another system and then added to solar system
Creators: name: Parsava, Benjamin
Publisher: name: Zenodo
Year: 2019
Subjects: Earth, Planet, Solar, Life

description: Until now, many theories for the birth of the earth have been proposed that some of them are accepted by most of scientific communities. However, earth has many differences with other planets of solar system, for example, life is observed only on this plant. In scientific theories, the reason for these differences is the separation distance between sun and the earth and also the existence of water and air which make the best condition for the emergence of life. However, another assumption may be considered so. Earth may be a planet that has been born in another system and then became separated from it’s real system and attracted by the sun. This assumption may be very distant of present theories, however, if it be true, we can search the origin of life on some other planets out of solar system.
Αυτορρύθμιση και κίνητρα επίτευξης σε μαθητές με μαθησιακές δυσκολίες και ήπια νοητική ανεπάρκεια.
Creators: name: Καραγεωργίου, Ελπίδα Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Αυτορρύθμιση
Κίνητρα
Μαθησιακές Δυσκολίες
Νοητική Ανεπάρκεια
Self-regulation
Motivation
learning disabilities
intellectual disabilities

description: Η ικανότητα ενός ατόμου να ελέγχει και να ρυθμίζει τη συμπεριφορά του θεωρείται ως ένα επιθυμητό χαρακτηριστικό που οδηγεί στην αυτονομία του. Ωστόσο η ικανότητα αυτή προϋποθέτει την επιθυμία ενασχόλησης του ατόμου με οποιαδήποτε δραστηριότητα. Οι θεωρίες της αυτορρύθμισης και των κινήτρων επίτευξης βρίσκουν άμεση εφαρμογή τόσο στα σχολικά περιβάλλοντα και την εμπλοκή του μαθητή στη μαθησιακή διαδικασία, όσο και σε θέματα που αφορούν τον κοινωνικό-συναισθηματικό τομέα και σχετίζονται με τις διαπροσωπικές σχέσεις και την επίλυση καθημερινών προβλημάτων. Στη παρούσα έρευνα συγκρίναμε τις αυτορρυθμιστικές ικανότητες και τα κίνητρα επίτευξης μαθητών με μαθησιακές δυσκολίες και μαθητών με ήπια νοητική ανεπάρκεια που εμφανίζουν, σύμφωνα με τη βιβλιογραφία, ελλείμματα στους παραπάνω τομείς. Τα αποτελέσματα της έρευνας συμφωνούν με την υπόθεση ότι θα υπάρχει απόκλιση μεταξύ των δύο ομάδων και στους δύο τομείς με τα παιδιά με ήπια νοητική ανεπάρκεια να σημειώνουν χαμηλότερα ποσοστά. Πιο συγκεκριμένα, προέκυψε από τα αποτελέσματα της έρευνας ότι οι μαθητές με ήπια νοητική ανεπάρκεια είναι περισσότερο προσανατολισμένοι στο κίνητρο αποφυγή της αποτυχίας και αυτό σχετίζεται αρνητικά τόσο με τη μαθησιακή διαδικασία όσο και με τον κοινωνικό-συναισθηματικό τομέα.
description: An individual's ability to control and adjust their behaviour is considered to be a desirable characteristic which leads to the individual's autonomy. However, this ability presuposes the individual's desire to take part in any kind of activity. The theories of self-regulation and the motivations of achievement are directly applied not only in school environments and in the student's involvement in the learning process, but also in issues that concern the social-emotional domain and are related to interpersonal relationships and the resolvement of everyday problems. In this research we have compared the self-regulation and the motivations of achievement of students with learning disabilities and of students with a mild intellectual disabilities who appear, according to bibliography, to have deficiencies in the above domains. The results of the research agree with the assumption that there will be a divergence between the two groups in both domains, where the children with a mild intellectual disabilities are in lower percentages. To be more specific, it has been noticed that students with mild intellectual disabilities are more orientated to the motivation of failure avoidance and this is negatively related not only to the learning process but also to the social-emotional domain.
Numerical simulations of semiconductor devices by streamline-diffusion methods
Creators: name: Jiang, Xunlei
Publisher: name: University of British Columbia
Year: 2009

description: Theoretical and practical aspects of the design and implementation of the streamlinediffusion (SD) method for semiconductor device models are explored systematically. Emphasis is placed on the hydrodynamic (HD) model, which is computationally more challenging than the drift-diffusion (DD) model, but provides some important physical information missing in the DD model. We devise a non-symmetric SD method for device simulations. This numerical method is uniformly used for the HD model (including a proposed simplification (SHD)) and the DD model. An appropriate SD operator is derived for the general non-symmetric convection-diffusion system. Linear stability analysis shows that our proposed numerical method is stable if the system can be symmetrized. Stability arguments and numerical experiments also suggest that the combination of the method of lines and the semidiscrete SD method may not be appropriate for the transient problem, a fact which often has been ignored in the literature. An efficient method, consistent with the SD method used for conservation laws, is developed for the potential equation. The method produces a more accurate electric field than the conventional Galerkin method. Moreover, it solves for the potential and electric field in a decoupled manner. We apply our numerical method to the diode and MESFET devices. Shocks for the diode in one and two space dimensions and the electron depletion near the gate for the MESFET in two space dimensions are simulated. Model comparisons are implemented. We observe that the difference in solutions between the HD and DD models is significant. The solution discrepancy between the full HD and SHD models is almost negligible in MESFET simulation, as in many other engineering applications. However, an exceptional case is found in our experiments.
Laboratory Measurements of Instrumental Signatures of the LSST Camera Focal Plane
Creators: name: Snyder, Adam
name: Barrau, Aurelien
name: Bradshaw, Andrew
name: Bowdish, Boyd
name: Chiang, James
name: Combet, Celine
name: Digel, Seth
name: Dubois, Richard
name: Eraud, Ludovic
name: Juramy, Claire
name: Lage, Craig
name: Lange, Travis
name: Migliore, Myriam
name: Nomerotski, Andrei
name: O'Connor, Paul
name: Park, HyeYun
name: Rasmussen, Andrew
name: Reil, Kevin
name: Roodman, Aaron
name: Shestakov, Adrian
name: Utsumi, Yousuke
name: Wood, Duncan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Electro-optical testing and characterization of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) Camera focal plane, consisting of 205 charge-coupled devices (CCDs) arranged into 21 stand-alone Raft Tower Modules (RTMs) and 4 Corner Raft Tower Modules (CRTMs), is currently being performed at the SLAC National Accelerator Laboratory. Testing of the camera sensors is performed using a set of custom-built optical projectors, designed to illuminate the full focal plane or specific regions of the focal plane with a series of light illumination patterns: the crosstalk projector, the flat illuminator projector, and the spot grid projector. In addition to measurements of crosstalk, linearity and full well, the ability to project realistically-sized sources, using the spot grid projector, makes possible unique measurements of instrumental signatures such as deferred charge distortions, astrometric shifts due to sensor effects, and the brighter-fatter effect, prior to camera first light. Here we present the optical projector designs and usage, the electro-optical measurements and how these results have been used in testing and improving the LSST Camera instrumental signature removal algorithms.
description: 21 pages, 16 figures. SPIE Astronomical Telescopes + Instrumentation Digital Forum December 2020
Testing UV-filtered ("fat-link") clover fermions
Creators: name: Capitani, Stefano
name: Durr, Stephan
name: Hoelbling, Christian
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We investigate filtered clover fermions, built from fat gauge links, both in one-loop perturbation theory and in numerical simulations. We use a variety of filtering recipes (APE, HYP, EXP, HEX), some of which are suitable for a HMC with dynamical fermions. A generic filtering together with a (fat-link) clover term yields fermions with much reduced chiral symmetry breaking.
description: 7 pages, Lattice 2006 (Quark Masses, Gauge Couplings, and Renormalization)
The source of variable optical emission is localized in the jet of the radio galaxy 3C 390.3
Creators: name: Arshakian, Tigran G.
name: Lobanov, Andrei P.
name: Chavushyan, Vahram H.
name: Shapovalova, Alla I.
name: Zensus, J. Anton
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present observational evidence for the link between variability of the radio emission of the relativistic jet and optical continuum emission in the radio galaxy 3C 390.3 which indicates that the source of variable non-thermal continuum radiation is located in the innermost part of the relativistic jet. We suggest that the continuum emission from the jet ionizes material in a subrelativistic outflow surrounding the jet, which results in a formation of a conical region with broad emission lines at a distance of about 0.4 parsecs from the central nucleus.
description: 3 pages, 4 figures, to be published in the proceedings of "Relativistic Astrophysics and Cosmology - Einstein's Legacy" meeting, November 7-11, 2005, Munich, Germany, edited by B. Aschenbach, V. Burwitz, G. Hasinger, and B. Leibundgut
Improving Students Performance in Small-Scale Online Courses -- A Machine Learning-Based Intervention
Creators: name: Azimi, Sepinoud
name: Popa, Carmen-Gabriela
name: Cucić, Tatjana
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computers and Society (cs.CY)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: The birth of massive open online courses (MOOCs) has had an undeniable effect on how teaching is being delivered. It seems that traditional in class teaching is becoming less popular with the young generation, the generation that wants to choose when, where and at what pace they are learning. As such, many universities are moving towards taking their courses, at least partially, online. However, online courses, although very appealing to the younger generation of learners, come at a cost. For example, the dropout rate of such courses is higher than that of more traditional ones, and the reduced in person interaction with the teachers results in less timely guidance and intervention from the educators. Machine learning (ML) based approaches have shown phenomenal successes in other domains. The existing stigma that applying ML based techniques requires a large amount of data seems to be a bottleneck when dealing with small scale courses with limited amounts of produced data. In this study, we show not only that the data collected from an online learning management system could be well utilized in order to predict students overall performance but also that it could be used to propose timely intervention strategies to boost the students performance level. The results of this study indicate that effective intervention strategies could be suggested as early as the middle of the course to change the course of students progress for the better. We also present an assistive pedagogical tool based on the outcome of this study, to assist in identifying challenging students and in suggesting early intervention strategies.
Evolutionary Design: Philosophy, Theory, and Application Tactics
Creators: name: Kryssanov, V. V.
name: Tamaki, H.
name: Kitamura, S.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Although it has contributed to remarkable improvements in some specific areas, attempts to develop a universal design theory are generally characterized by failure. This paper sketches arguments for a new approach to engineering design based on Semiotics - the science about signs. The approach is to combine different design theories over all the product life cycle stages into one coherent and traceable framework. Besides, it is to bring together the designer's and user's understandings of the notion of 'good product'. Building on the insight from natural sciences that complex systems always exhibit a self-organizing meaning-influential hierarchical dynamics, objective laws controlling product development are found through an examination of design as a semiosis process. These laws are then applied to support evolutionary design of products. An experiment validating some of the theoretical findings is outlined, and concluding remarks are given.
description: 6 pages, 3 figures. Preprint completed in 1999
Initial Reports of the Deep Sea Drilling Project - Volume 73
Creators: name: Hsü, K.J.
name: LaBrecque, J.L.
name: The Leg 73 Science Party
Publisher: name: U.S. Government Printing Office
Year: 1984
Subjects: Deep Sea Drilling Project
Glomar Challenger
DSDP
Leg 73
Site 519
Site 520
Site 521
Site 522
Site 523
Site 524
South Atlantic Ocean
Mid-Atlantic Ridge

description: This volume covers Leg 73 of the cruises of the Drilling Vessel Glomar Challenger. Leg 73 was the middle of five legs on South Atlantic paleoenvironments planned by the JOIDES Ocean Paleoenvironment (OP) Panel during the years from 1975 to 1980. The objectives and tactical planning for a transect across the east flank of the Mid-Atlantic Ridge just north of 30°S were outlined by the OP Panel. Drilling was proposed at three sites clustered near the ridge to obtain information on the middle Miocene CCD crisis; a second group of four sites, farther to the east, would be drilled to obtain information on the Eocene-Oligocene paleoceanographic revolution triggered by the onset of Antarctic glaciation. In addition, crustal sampling was planned at all sites to obtain datable material for a more precise determination of the seafloor spreading history in this region. Two broad aims of the cruise were spelled out, namely (1) to investigate the Cenozoic oceanography of the South Atlantic, particularly temperature gradients, circulation patterns, water chemistry, and biotic communities and their environmental adaptation and evolution, and (2) to develop the correlation between the reversal history of the Earth's magnetic field and biostratigraphic zonations. Precisely dated samples would be used to determine the timing and duration of specific paleoceanographic events during the last 70 m.y. In addition, paleomagnetic samples were to provide field direction and intensity data for a study of Cenozoic geomagnetic field phenomena. The Glomar Challenger left Santos, Brazil on April 13, and arrived at Cape Town, South Africa, on June 1,1980. During the 49 days at sea, we drilled 13 holes at six sites and recovered more than 1000 m of core.
การศึกษาพฤติกรรมและทัศนคติในการเปิดรับชมสื่อโฆษณาทางอินเทอร์เน็ต
Creators: name: ผุสดี วัฒนสาคร
Publisher: name: วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Year: 2549
Subjects: การเปิดรับชมสื่อ,โฆษณา,อินเทอร์เน็ต

description: 1, 2, วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Safe Optimal Control Using Stochastic Barrier Functions and Deep Forward-Backward SDEs
Creators: name: Pereira, Marcus Aloysius
name: Wang, Ziyi
name: Exarchos, Ioannis
name: Theodorou, Evangelos A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Systems and Control (eess.SY)
subject: Artificial Intelligence (cs.AI)
subject: Robotics (cs.RO)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: This paper introduces a new formulation for stochastic optimal control and stochastic dynamic optimization that ensures safety with respect to state and control constraints. The proposed methodology brings together concepts such as Forward-Backward Stochastic Differential Equations, Stochastic Barrier Functions, Differentiable Convex Optimization and Deep Learning. Using the aforementioned concepts, a Neural Network architecture is designed for safe trajectory optimization in which learning can be performed in an end-to-end fashion. Simulations are performed on three systems to show the efficacy of the proposed methodology.
Quantifier elimination for approximate Beals-Kartashova factorization
Creators: name: Kartashova, Elena
name: McCallum, Scott
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The only known constructive factorization algorithm for linear partial differential operators (LPDOs) is Beals-Kartashova (BK) factorization \cite{bk2005}. One of the most interesting features of BK-factorization: at the beginning all the first-order factors are constructed and afterwards the factorization condition(s) should be checked. This leads to the important application area - namely, numerical simulations which could be simplified substantially if instead of computation with one LPDE of order $n$ we will be able to proceed computations with $n$ LPDEs all of order 1. In numerical simulations it is not necessary to fulfill factorization conditions exactly but with some given accuracy, which we call approximate factorization. The idea of the present paper is to look into the feasibility of solving problems of this kind using quantifier elinination by cylindrical algebraic decomposition.
Discrete Approximation of Quantum Stochastic Models
Creators: name: Bouten, Luc
name: van Handel, Ramon
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We develop a general technique for proving convergence of repeated quantum interactions to the solution of a quantum stochastic differential equation. The wide applicability of the method is illustrated in a variety of examples. Our main theorem, which is based on the Trotter-Kato theorem, is not restricted to a specific noise model and does not require boundedness of the limit coefficients.
Spectroscopic evidence for possible quantum spin liquid behavior in a two-dimensional Mott insulator
Creators: name: Chen, Haiyang
name: Wang, Fo-Hong
name: Gao, Qiang
name: Gao, Xue-Jian
name: Chen, Zhenhua
name: Huang, Yaobo
name: Law, Kam Tuen
name: Xu, Xiao Yan
name: Chen, Peng
Publisher: name: arXiv
Year: 2025
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Mott insulators with localized magnetic moments will exhibit a quantum spin liquid (QSL) state when the quantum fluctuations are strong enough to suppress the ordering of the spins. Such an entangled state will give rise to collective excitations, in which spin and charge information are carried separately. Our angle-resolved photoemission spectroscopy (ARPES) measurements on single-layer 1T-TaS2 show a flat band around the zone center and a gap opening of about 200 meV in the low temperature, indicating 2D Mott insulating nature in the system. This flat band is dispersionless in momentum space but shows anomalously broad width around the zone center and the spectral weight decays rapidly as momentum increases. The observation is described as a spectral continuum from electron fractionalization, corroborated by a low energy effective model.The intensity of the flat band is reduced by surface doping with magnetic adatoms and the gap is closing, a result from the interaction between spin impurities coupled with spinons and the chargons, which gives rise to a charge redistribution. Doping with nonmagnetic impurities behaves differently as the chemical potential shift dominates. These findings provide insight into the QSL states of strongly correlated electrons on 2D triangular lattices.
A cuspy dark matter halo
Creators: name: Shi, Yong
name: Zhang, Zhi-Yu
name: Wang, Junzhi
name: Chen, Jianhang
name: Gu, Qiusheng
name: Yu, Xiaoling
name: Li, Songlin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The cusp-core problem is one of the main challenges of the cold dark matter paradigm on small scales: the density of a dark matter halo is predicted to rise rapidly toward the center as rho ~ r^alpha with alpha between -1 and -1.5, while such a cuspy profile has not been clearly observed. We have carried out the spatially-resolved mapping of gas dynamics toward a nearby ultra-diffuse galaxy (UDG), AGC 242019. The derived rotation curve of dark matter is well fitted by the cuspy profile as described by the Navarro-Frenk-White model, while the cored profiles including both the pseudo-isothermal and Burkert models are excluded. The halo has alpha=-(0.90+-0.08) at the innermost radius of 0.67 kpc, Mhalo=(3.5+-1.2)E10 Msun and a small concentration of 2.0+-0.36. AGC 242019 challenges alternatives of cold dark matter by constraining the particle mass of fuzzy dark matter to be < 0.11E-22 eV or > 3.3E-22 eV , the cross section of self-interacting dark matter to be < 1.63 cm2/g, and the particle mass of warm dark matter to be > 0.23 keV, all of which are in tension with other constraints. The modified Newtonian dynamics is also inconsistent with a shallow radial acceleration relationship of AGC 242019. For the feedback scenario that transforms a cusp to a core, AGC 242019 disagrees with the stellar-to-halo-mass-ratio dependent model, but agrees with the star-formation-threshold dependent model. As a UDG, AGC 242019 is in a dwarf-size halo with weak stellar feedback, late formation time, a normal baryonic spin and low star formation efficiency (SFR/gas).
description: ApJ accepted, 25 pages, 17 figures
Thermodynamics via Creation from Nothing: Limiting the Cosmological Constant Landscape
Creators: name: Barvinsky, A. O.
name: Kamenshchik, A. Yu.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The creation of a quantum Universe is described by a {\em density matrix} which yields an ensemble of universes with the cosmological constant limited to a bounded range $Λ_{\rm min}\leq Λ\leq Λ_{\rm max}$. The domain $Λ
description: RevTex, 4 pages, 4 figures
A Behaviour Model as Extension for the Object-Oriented World Model
Creators: name: Anneken, Mathias
Publisher: name: Karlsruhe
Year: 2019

description: This report focuses on extending the object-oriented world model by a behaviour model for its representatives. The world model in general is used as a foundation for fusing multiple sensor sources into one coherent picture. It should enable other services to access the stored information for further processing, e.g. for recognizing suspicious situations in surveillance tasks. While the base model is able to capture the real world entities by translating them into representatives while incorporating background-knowledge in form of concepts, it is not able to predict the behaviour of these representatives. Here, a concept based on intelligent rational agents is introduced.
Stabilization methods for simulations of constrained multibody dynamics
Creators: name: Chin, Hong Sheng
Publisher: name: University of British Columbia
Year: 2009

description: The descriptor form of constrained multibody systems, and any general formulation of such systems with closed loops, yield index-3 differential-algebraic equations (DAEs). Generally, some index reduction techniques have to be used before numerical discretization can be safely applied. However, a direct differentiation of the constraints introduces mild instability. Hence one must consider index reduction with stabilization. One popular method for index reduction with stabilization is Baumgarte's technique. However the difficulty of choosing the parameters in practice makes this method's robustness unclear. Moreover our numerical experiments show that there are still large constraint drifts even with Baumgarte's stabilization. In the thesis, we employ concepts and techniques of dynamical systems in order to improve the situation. We first study the relationship between a DAE and its underlying vector fields. A general form of vector fields with stabilized invariant manifolds is given. We propose a new numerical stabilization method for semi-explicit index-2 and index-3 DAEs of Hessenberg form. Our stabilization method improves on Baumgarte's stabilization which is widely used in engineering as well as in simulations of multibody systems. We then develop a numerical code based on the new stabilization method with an adaptive step-size control for the descriptor form of the Euler-Lagrange equations in multibody systems. Numerical simulations have been conducted with our code on a variety of multibody systems including a spatial five-link-suspension model in a vehicle, Andrews squeezing mechanism, a two-arm manipulator with a prescribed motion and a mechanism with kinematic singularity. Our code is efficient, fast and therefore is more attractive for real-time simulations. When high speed and light-weight substructures are involved in the multibody system, the rigid body model is usually no longer valid. In such a case we compute the elastic deformations and oscillations of the substructures using the finite element method. Satisfactory numerical results using our method are presented for deformable multibody systems as well.
Stochasticity and Non-locality of Time
Creators: name: Ohira, Toru
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Physics (physics.gen-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: We present simple classical dynamical models to illustrate the idea of introducing a stochasticity with non-locality into the time variable. For stochasticity in time, these models include noise in the time variable but not in the "space" variable, which is opposite to the normal description of stochastic dynamics. Similarly with respect to non-locality, we discuss delayed and predictive dynamics which involve two points separated on the time axis. With certain combinations of fluctuations and non-locality in time, we observe a ``resonance'' effect. This is an effect similar to stochastic resonance, which has been discussed within the normal context of stochastic dynamics, but with different mechanisms. We discuss how these models may be developed to fit a broader context of generalized dynamical systems where fluctuations and non-locality are present in both space and time.
description: 12 pages, 5 figures, Accepted and to appear in Physica A. (reference corrected for ver. 2)
Constraining the Halo Mass of Damped Ly$α$ Absorption Systems (DLAs) at $z=2-3.5$ using the Quasar-CMB Lensing Cross-correlation
Creators: name: Lin, Xiaojing
name: Cai, Zheng
name: Li, Yin
name: Krolewski, Alex
name: Ferraro, Simone
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the cross correlation of damped Ly$α$ systems (DLAs) and their background quasars, using the most updated DLA catalog and the Planck 2018 CMB lensing convergence field. Our measurement suggests that the DLA bias $b_{\rm DLA}$ is smaller than $3.1$, corresponding to $\log(M/M_\odot h^{-1})\leq 12.3$ at a confidence of $90\%$. These constraints are broadly consistent with Alonso et al. (2018) and previous measurements by cross-correlation between DLAs and the Ly$α$ forest (e.g. Font-Ribera et al. 2012; Perez-Rafols et al. 2018). Further, our results demonstrate the potential of obtaining a more precise measurement of the halo mass of high-redshift sources using next generation CMB experiments with a higher angular resolution. The python-based codes and data products of our analysis are available at https://github.com/LittleLin1999/CMB-lensingxDLA.
description: Accepted for Publication in ApJ; 16 pages, 9 figures
Investigating the Influence of Computer Anxiety on the Academic Performance of Junior Secondary School Students in Computer Studies in Nigeria
Creators: name: Oribhabor, Chinelo Blessing
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: This study examined the influence of computer anxiety on the academic performance of junior secondary school students in Computer Studies in Nigeria. The research instrument that was used in the study was computer anxiety scale which was validated by the Guidance and Counseling lecturers and Educational Measurement and Evaluation experts. The result of the study showed that most of the students used in the study were mildly anxious when dealing with computer.
description: 12 pages
Wurtzite III-nitride distributed Bragg reflectors on Si (100) substrates
Creators: name: Mastro, M. A.
name: Holm, R. T.
name: Bassim, N. D.
name: Eddy,, C. R.
name: Henry, R. L.
name: Twigg, M. E.
name: Rosenberg, A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Distributed Bragg reflectors (DBRs) composed of an AlN/GaN superlattice were demonstrated for the first time on Si (100) substrates. Single-crystal wurtzite superlattice structures were achieved on this cubic substrate by employing offcut Si (100) wafers with the surface normal pointing 4° towards the [110] direction. This misorientation introduced an additional epitaxial constraint that prevented the growth of a two-domain GaN surface as well as cubic GaN inclusions. A crack-free 600 nm GaN cap / 5x AlN / GaN DBR structure on Si (100) was demonstrated. This accomplishment of a wurtzite III-nitride DBRs on Si (100) opens the possibility to integrate novel optical and optoelectronic devices with established Si microelectronics technology.
In vitro έλεγχος της συγκράτησης και της αντίστασης στην εκτόπιση στεφανών ολικής κάλυψης προσθίων δοντιών με 2 διαφορετικούς τρόπους προπαρασκευής.
Creators: name: Μπιντιβάνου, Αιμιλία Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Συγκράτηση
Αντίσταση στην εκτόπιση
Υπερώϊο έπαρμα
Retention
Resistance
Cingulum

description: Σκοπός της διατριβής ήταν να εκτιμηθεί κατά πόσο η τροποποίηση της κλασικής παρασκευής των προσθίων δοντιών της άνω γνάθου -χωρίς την ύπαρξη παράλληλου παρειακού και υπερώϊου αξονικού τοιχώματος- επηρεάζει τη συγκράτηση και την αντίσταση στην εκτόπιση. Εξετάσαμε τη βιβλιογραφία που υπάρχει για τις συγκεκριμένες διαδικασίες και τους τρόπους παρασκευής καθώς και τις προϋποθέσεις που έχουν προταθεί. Στη συνέχεια παρουσιάσαμε αναλυτικά τα εργαστηριακά βήματα που ακολουθήθηκαν, καθώς και τα υλικά και τον τρόπο εκτέλεσης της κάθε δοκιμασίας. Ακόμη αναφερθήκαμε αναλυτικά στη στατιστική ερμηνεία των αποτελεσμάτων και στην κλινική εφαρμογή αυτών. Ένα άλλο θέμα που θίξαμε ήταν οι περιορισμοί και τα κλινικά προβλήματα που μπορούν να προκύψουν από την εφαρμογή της συγκεκριμένης παρασκευής δοντιών καθώς και τη μελλοντική βελτίωση του τεχνικού τομέα γι ακόμη πιο σαφή και λεπτομερή αποτελέσματα που ενδέχεται να προκύψουν.
description: The aim of the present study was to evaluate and compare the retention and resistance failure loads of 2 preparation designs for maxillary anterior teeth. We examined the proposed bibliography for these specific procedures, the preparation designs and the demanded conditions. Then we presented the laboratory procedure that was followed, the materials that were used and the way each step was conducted. Furthermore, we analyzed the statistical explanation of the results and their clinical meaning. We also examined the limitations and the clinical problems that may occur as a result of this specific procedure of teeth preparation. We also suggested a future development of the technical part and methods in order to have more specific results.
Hot Jupiter and ultra-cold Saturn formation in dense star clusters
Creators: name: Wang, Yi-Han
name: Leigh, Nathan W. C.
name: Perna, Rosalba
name: Shara, Michael M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The discovery of high incidence of hot Jupiters in dense clusters challenges the field-based hot Jupiter formation theory. In dense clusters, interactions between planetary systems and flyby stars are relatively common. This has a significant impact on planetary systems, dominating hot Jupiter formation. In this paper, we perform high precision, few-body simulations of stellar flybys and subsequent planet migration in clusters. A large parameter space exploration demonstrates that close flybys that change the architecture of the planetary system can activate high eccentricity migration mechanisms: Lidov-Kozai and planet-planet scattering, leading to high hot Jupiter formation rate in dense clusters. Our simulations predict that many of the hot Jupiters are accompanied by "ultra-cold Saturns", expelled to apastra of thousands of AU. This increase is particularly remarkable for planetary systems originally hosting two giant planets with semi-major axis ratios $\sim$ 4 and the flyby star approaching nearly perpendicular to the planetary orbital plane. The estimated lower limit to the hot Jupiter formation rate of a virialized cluster is $\sim 1.6\times10^{-4}(σ/{\rm 1kms^{-1}})^5({a_{\rm p}}/{\rm 20 AU})({M_{\rm c}}/{\rm 1000M_\odot})^{-2}$Gyr$^{-1}$ per star, where $σ$ is the cluster velocity dispersion, $a_{\rm p}$ is the size of the planetary system and $M_{\rm c}$ is the mass of the cluster. Our simulations yield a hot Jupiter abundance which is $\sim$ 50 times smaller than that observed in the old open cluster M67. We expect that interactions involving binary stars, as well as a third or more giant planets, will close the discrepancy.
description: Accepted for publication in ApJS
Three-dimensional correlated-fermion phase separation from analysis of the geometric mean of the individual susceptibilities
Creators: name: Chen, Ji-sheng
name: Qin, Fang
name: Wang, Yan-ping
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: A quasi-Gaussian approximation scheme is formulated to study the strongly correlated imbalanced fermions thermodynamics, where the mean-field theory is not applicable. The non-Gaussian correlation effects are understood to be captured by the statistical geometric mean of the individual susceptibilities. In the three-dimensional unitary fermions ground state, an {\em universal} non-linear scaling transformation relates the physical chemical potentials with the individual Fermi kinetic energies. For the partial polarization phase separation to full polarization, the calculated critical polarization ratio is $P_C={[1-(1-ξ)^{6/5}]}/{[1+(1-ξ)^{6/5}]}\doteq 0.34$. The $ξ=4/9$ defines the ratio of the symmetric ground state energy density to that of the ideal fermion gas.
description: Minor changes with typos corrected
Modelling the dynamics of actin in cells
Creators: name: Civelekoglu, Esma Gul
Publisher: name: University of British Columbia
Year: 2009

description: The cytoskeleton is a macromolecular scaffold which gives the cell its shape and controls cellular motion. Actin is the most abundant proteins in the cytoskeleton and an impor tant determinant of its structure and mechanical properties. Actin monomers polymerize into filaments that are then linked to one another by a variety of binding proteins. Fil aments can organize into unipolar and bipolar bundles as well as orthogonal networks. The formation of these structures and the transitions between them depend on the types, quantities, and properties of the binding proteins. The problem addressed in this thesis concerns interactions of actin filaments with actin binding proteins. I investigate the main mechanisms governing the formation of a variety of cytoskeletal actin structures as well as transitions between them. In particular I discuss how the type of binding protein and its binding kinetics affects the structures formed. I further investigate the influence of the geometry of the molecules and the dimensionality of the environment (for example the presence of a surface near which the structures form). Dynamic continuum models analogous to the mean field approximation in physics are used to study the time evolution of angular distributions of actin filaments. Integro partial differential equations are derived for two types of events: (a) rapid binding of filaments, and (b) gradual turning and alignment of filaments. Linear stability analysis is applied to 2D and 3D versions of such models. Numerical analysis and explicit solutions are discussed in special cases. It is found that as the actin filament density increases in the cell, a spontaneous tendency to organize into bundles or networks occurs. Both the linear stability anal ysis and the nnmerical results indicate that the structures formed are highly sensitive to changes in the parameters including the total mass of actin filaments, the rotational diffusion coefficient and rate constants representing binding and unbinding. Criteria (in volving combinations of these parameters) are obtained for instability of the homogeneous steady state and appearance of order. Similar results are obtained for both rapid and gradual alignment models, suggesting robustness of the modelling approach.
Εγκεφαλικός θάνατος νεογνών και παιδιών: ιατρική, ηθική και νομική διάσταση
Creators: name: Καραμέτου, Γρηγορία-Μαργαρίτα Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Εγκεφαλικός θάνατος
Νεογνά
Ανεγκεφαλία
Brain death
Infants
Anencephaly

description: Οι εξελίξεις στον τομέα της ιατρικής με την εμφάνιση των μονάδων εντατικής θεραπείας και των δυνατοτήτων στήριξης της καρδιοαναπνευστικής λειτουργίας του ασθενή δημιούργησαν έναν νέο θάνατο, τον εγκεφαλικό. Χρειάστηκαν πολλές δεκαετίες μέχρι να διαμορφωθούν τα κριτήρια καθορισμού του εγκεφαλικού θανάτου, δημιουργώντας παράλληλα ένα κύμα αντιπαραθέσεων και αμφισβητήσεων από τον ιατρικό, φιλοσοφικό και νομικό χώρο για το κατά πόσο αυτός ο θάνατος αποτελεί τον πραγματικό θάνάτο του ατόμου. Ιδιαίτερο ενδιαφέρον είχε ο εγκεφαλικός θάνατος νεογνών και παιδιών μια και για αρκετό καιρό δεν υπήρχαν ξεχωριστά κριτήρια γι’αυτά λόγω ανεπαρκών δεδομένων. Επιπλέον η πρόταση εξαίρεσης των ανεγκεφαλικών νεογνών από τα κριτήρια εγκεφαλικού θανάτου ώστε να μπορούν να χρησιμοποιηθούν ως δωρητές οργάνων έφερε διχασμό στον επιστημονικό κόσμο. Η έλλειψη ενός κοινού νομοθετικού πλαισίου πάνω στον εγκεφαλικό θάνατο μεταξύ των χωρών δυσχαιρένει την κατάσταση επιτρέποντας διαφορετική ερμηνεία και εφαρμογή των κριτηρίων ανά τον κόσμο.
description: Development in the field of medicine with the advent of intensive care units and the capability of supporting cardiopulmonary function has led to the definition of brain death. Many decades passed until the ctiteria for brain death where established creating arguments and disputes in the medical, philosophical and legal area, whether this death is the real death of the individual. Brain death of infants and children was of particular interest because for a long time there had been no separate criteria, due to insufficient data. Moreover, the proposal of excluding anencephalic infants from the criteria of brain death, so that they could be used as sources of transplantable organs, was one of the most controversial issues in medical ethics. The lack of a common legislation on brain death among countries allows different interpretation and application of the criteria in the world.
Determining the Number of Sinusoids Measured with Errors
Creators: name: Kharin, Aleksandr
name: Chernoyarov, Oleg V.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper describes how a priori information about the signal parameters can influence the accuracy of estimating the number of these signals. This study considers sinusoidal signals and it is supposed that the parameters (amplitudes, frequencies and phases) of the received signals are known up to a certain error. The error probability of the maximum likelihood estimation of the number of sinusoids is calculated under this condition.
Neutrino Masses and Mixing in Models with Large Extra Dimensions and Localized Fermions
Creators: name: Girmohanta, S.
name: Mohapatra, R. N.
name: Shrock, R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Using a low-energy effective field theory approach, we study some properties of models with large extra dimensions, in which quarks and leptons have localized wave functions in the extra dimensions. We consider models with two types of gauge groups: (i) the Standard-Model gauge group, and (ii) the left-right symmetric (LRS) gauge group. Our main focus is on the lepton sector of models with $n=2$ extra dimensions, in particular, neutrino masses and mixing. We analyze the requisite conditions that the models must satisfy to be in accord with data and present a solution for lepton wave functions in the extra dimensions that fulfills these conditions. As part of our work, we also present a new solution for quark wave function centers. Issues with flavor-changing neutral current effects are assessed. Finally, we remark on baryogenesis and dark matter in these models.
description: 38 pages, 1 figure
Infinite primitive directed graphs
Creators: name: Smith, Simon
Publisher: name: arXiv
Year: 2006
Subjects: subject: Combinatorics (math.CO)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 05C20, 20B15

description: A group $G$ of permutations of a set $Ω$ is {\em primitive} if it acts transitively on $Ω$, and the only $G$-invariant equivalence relations on $Ω$ are the trivial and universal relations. A graph $Γ$ is {\em primitive} if its automorphism group acts primitively on its vertex set. A graph $Γ$ has {\em connectivity one} if it is connected and there exists a vertex $α$ of $Γ$, such that the induced graph $Γ\setminus \{α\}$ is not connected. If $Γ$ has connectivity one, a {\em block} of $Γ$ is a connected subgraph that is maximal subject to the condition that it does not have connectivity one. The primitive undirected graphs with connectivity one have been fully classified by Jung and Watkins: the blocks of such graphs are primitive, pairwise-isomorphic and have at least three vertices. When one considers the general case of a directed primitive graph with connectivity one, however, this result no longer holds. In this paper we investigate the structure of these directed graphs, and obtain a complete characterisation.
description: 12 pages