cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Virtual Light Transport Matrices for Non-Line-Of-Sight Imaging
Creators: name: Marco, Julio
name: Jarabo, Adrian
name: Nam, Ji Hyun
name: Liu, Xiaochun
name: Cosculluela, Miguel Ángel
name: Velten, Andreas
name: Gutierrez, Diego
Publisher: name: arXiv
Year: 2021
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: The light transport matrix (LTM) is an instrumental tool in line-of-sight (LOS) imaging, describing how light interacts with the scene and enabling applications such as relighting or separation of illumination components. We introduce a framework to estimate the LTM of non-line-of-sight (NLOS) scenarios, coupling recent virtual forward light propagation models for NLOS imaging with the LOS light transport equation. We design computational projector-camera setups, and use these virtual imaging systems to estimate the transport matrix of hidden scenes. We introduce the specific illumination functions to compute the different elements of the matrix, overcoming the challenging wide-aperture conditions of NLOS setups. Our NLOS light transport matrix allows us to (re)illuminate specific locations of a hidden scene, and separate direct, first-order indirect, and higher-order indirect illumination of complex cluttered hidden scenes, similar to existing LOS techniques.
description: ICCV 2021 (Oral)
Adiabatic Domain Wall Motion and Landau-Lifshitz Damping
Creators: name: Stiles, M. D.
name: Saslow, W. M.
name: Donahue, M. J.
name: Zangwill, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Recent theory and measurements of the velocity of current-driven domain walls in magnetic nanowires have re-opened the unresolved question of whether Landau-Lifshitz damping or Gilbert damping provides the more natural description of dissipative magnetization dynamics. In this paper, we argue that (as in the past) experiment cannot distinguish the two, but that Landau-Lifshitz damping nevertheless provides the most physically sensible interpretation of the equation of motion. From this perspective, (i) adiabatic spin-transfer torque dominates the dynamics with small corrections from non-adiabatic effects; (ii) the damping always decreases the magnetic free energy, and (iii) microscopic calculations of damping become consistent with general statistical and thermodynamic considerations.
Ανάπτυξη ηλεκτρονικού παιχνιδιού για τη μουσική ακουστική εκπαίδευση παιδιών με κοχλιακό εμφύτευμα
Creators: name: Βελένης, Κωνσταντίνος Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: κοχλιακό εμφύτευμα
παιχνιδοποίηση
εκπαιδευτική εφαρμογή
cochlear implant
gamification
educational software

description: Στη παρούσα εργασία μελετάται η ανάπτυξη ηλεκτρονικού παιχνιδιού με στόχο την μουσική ακουστική εκπαίδευση παιδιών με κοχλιακό εμφύτευμα. Έρευνες δείχνουν ότι μέσω της μουσικής ακουστικής εκπαίδευσης τα ατόμων με κοχλιακό εμφύτευμα πέρα από τη βελτίωση της μουσικής αντιληπτικής τους ικανότητας, μπορούν να επωφεληθούν και σε άλλα επίπεδα ακουστικής αντίληψης που σχετίζονται με την ενίσχυση της ακουστικής προσοχής και της μνήμης, την αντίληψη ομιλίας σε θορυβώδες περιβάλλον, τη βελτίωση της αντίληψης της προσωδίας των λεκτικών εκφράσεων κ.ά. Η έρευνα επικεντρώνεται στην μελέτη παρεμφερών εφαρμογών ακουστικής εκπαίδευσης και στην αναγνώριση των τεχνικών παιχνιδοποίησης που μπορούν να συμβάλλουν στην ανάπτυξη μιας εκπαιδευτικής εφαρμογής που να μπορεί να αποτελέσει μέρος της καθημερινότητας του θεραπευόμενου, αυξάνοντας την ενεργή του εμπλοκή στη διαδικασία της ακουστικής του αποκατάστασης. Στη συνέχεια αναλύεται η σχεδίαση και η ανάπτυξη της υλοποίησης του προτεινόμενου εκπαιδευτικού παιχνιδιού “Μουσικούπολη”. Παρουσιάζονται ο εκπαιδευτικός στόχος, οι εφαρμοσμένες τεχνικές παιχνιδοποίησης της εκπαιδευτικής εφαρμογής, η διαδικασίες πολυμεσικής παραγωγής του εκπαιδευτικού υλικού, ο προγραμματιστικός κώδικας της υλοποιημένης εφαρμογής και προτάσεις για πιθανές μελλοντικές προσθήκες και βελτιώσεις
description: The present research examines the development of an electronic game “Music Town” with the musical auditory training of children with cochlear implant as its target. Previous research has shown that through musical auditory training, people with cochlear implant in addition to improving their musical perception, can also benefit from other levels of auditory perception such as enhanced auditory attention and memory, speech perception in a noisy environment, speech prosody perception etc. The research focuses on studying similar applications of auditory training and identifying gamification techniques that can contribute to the development of an educational application which becomes part of the patient’s daily life, thus increasing his or her active involvement in the process of acoustic rehabilitation. Furthermore, the design and the development of the implementation of the proposed educational game “Music Town”, is analyzed. The educational goal, the applied gamification techniques of the educational application, the multimedia production processes of the educational material, the programming code and further suggestions for possible future additions and improvements, are presented and discussed
description: Σε συνεργασία με: Λογιστικής και Χρηματοοικονομικής (Πανεπιστήμιο Μακεδονίας)
Measurement of χ_cJ--> K+K-K+K-
Creators: name: BES Collaboration
name: AblikimJ, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Using 14M psi(2S) events taken with the BES-II detector, chi_cJ-->K+K-K+K- decays are studied. For the four-kaon final state, the branching fractions are B(chi_c0,1,2 -->K+K-K+K-)=(3.48\pm 0.23\pm 0.47)\times 10^{-3}, (0.70\pm 0.13\pm 0.10)\times 10^{-3}, and (2.17\pm 0.20\pm 0.31)\times 10^{-3}. For the ϕK+K- final state, the branching fractions, which are measured for the first time, are B(chi_c0,1,2-->ϕK+K-)=(1.03\pm 0.22\pm 0.15)\times 10^{-3}, (0.46\pm 0.16\pm 0.06)\times 10^{-3}, and (1.67\pm 0.26\pm 0.24)\times 10^{-4}. For the ϕϕfinal state, B(chi_{c0,2}-->ϕϕ)=(0.94\pm 0.21\pm 0.13)\times 10^{-3} and (1.70\pm 0.30\pm 0.25)\times 10^{-3}.
description: 7 pages, 7 figures
A high-significance detection of non-Gaussianity in the WMAP 5-year data using directional spherical wavelets
Creators: name: McEwen, J. D.
name: Hobson, M. P.
name: Lasenby, A. N.
name: Mortlock, D. J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We repeat the directional spherical real Morlet wavelet analysis, used to detect non-Gaussianity in the Wilkinson Microwave Anisotropy Probe (WMAP) 1-year and 3-year data (McEwen et al. 2005, 2006a), on the WMAP 5-year data. The non-Gaussian signal detected previously is present in the 5-year data at a slightly increased statistical significance of approximately 99%. Localised regions that contribute most strongly to the non-Gaussian signal are found to be very similar to those detected in the previous releases of the WMAP data. When the localised regions detected in the 5-year data are excluded from the analysis the non-Gaussian signal is eliminated.
description: 4 pages, 4 figures, replaced to match version accepted by MNRAS, masks available for download
The quantum theory of measurement within dynamical reduction models
Creators: name: Bassi, A.
name: Salvetti, D. G. M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We analyze in mathematical detail, within the framework of the QMUPL model of spontaneous wave function collapse, the von Neumann measurement scheme for the measurement of a 1/2 spin particle. We prove that, according to the equation of the model: i) throughout the whole measurement process, the pointer of the measuring device is always perfectly well localized in space; ii) the probabilities for the possible outcomes are distributed in agreement with the Born probability rule; iii) at the end of the measurement the state of the microscopic system has collapsed to the eigenstate corresponding to the measured eigenvalue. This analysis shows rigorously how dynamical reduction models provide a consistent solution to the measurement problem of quantum mechanics.
description: 24 pages, RevTeX. Minor changes made
Search for D to phi l nu and measurement of the branching fraction for D to phi pi
Creators: name: Ablikim, M.
name: Collaboration, The BES
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Using a data sample of integrated luminosity of about 33 pb$^{-1}$ collected around 3.773 GeV with the BESII detector at the BEPC collider, the semileptonic decays $D^+ \to ϕe ^+ν_e$, $D^+ \to ϕμ^+ν_μ$ and the hadronic decay $D^+ \to ϕπ^+$ are studied. The upper limits of the branching fractions are set to be $BF(D^+ \to ϕe ^+ν_e)
description: 6 pages, 5 figures, to be published in Eur.Phys.J.C
Massive Domain Wall Fermions on Four-dimensional Anisotropic Lattices
Creators: name: Feng, Xu
name: Li, Xin
name: Liu, Wei
name: Liu, Chuan
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We formulate the massive domain wall fermions on anisotropic lattices. For the massive domain wall fermion, we find that the dispersion relation assumes the usual form in the low momentum region when the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. For light domain wall fermions, we verified that the chiral mode is stable against quantum fluctuations on anisotropic lattices. This calculation serves as a guidance for the tuning of the parameters in the quark action in future numerical simulations.
description: 36 pages, 14 figures, references added
Transverse Kähler holonomy in Sasaki Geometry and ${\oldmathcal S}$-Stability
Creators: name: Boyer, Charles P.
name: Huang, Hongnian
name: Tønnesen-Friedman, Christina V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Differential Geometry (math.DG)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics

description: We study the transverse Kähler holonomy groups on Sasaki manifolds $(M,{\oldmathcal S})$ and their stability properties under transverse holomorphic deformations of the characteristic foliation by the Reeb vector field. In particular, we prove that when the first Betti number $b_1(M)$ and the basic Hodge number $h^{0,2}_B({\oldmathcal S})$ vanish, then ${\oldmathcal S}$ is stable under deformations of the transverse Kähler flow. In addition we show that an irreducible transverse hyperkähler Sasakian structure is ${\oldmathcal S}$-unstable, whereas, an irreducible transverse Calabi-Yau Sasakian structure is ${\oldmathcal S}$-stable when $\dim M\geq 7$. Finally, we prove that the standard Sasaki join operation (transverse holonomy $U(n_1)\times U(n_2)$) as well as the fiber join operation preserve ${\oldmathcal S}$-stability.
description: 33 pages. An incorrect lemma was removed, and appropriate revisions made. Paper shortened by removing categorical details. Comments welcome
: Προσδιορισμός του γ-υδροξυβουτυρικού οξέος σε ανθρώπινα βιολογικά υγρά, αίμα ή ούρα, με υγρή χρωματογραφία - φασματομετρία μάζας
Creators: name: Καραπέτσα, Μαρίνα Σωτηρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Κλινική Φαρμακολογία
Βιομηχανική Φαρμακολογία
Κλινική Τοξικολογία
Καταγραφή
Clinical Pharmacology
Industrial Pharmacology
Clinical Toxicology
Reference

description: Το γ-υδροξυβουτυρικό οξύ (GHB) που είναι ένα ύδροξυ- οξύ μικρού μήκους αλυσίδας, είναι νευροδιαβιβαστής και αποτελεί πρόδρομο μόριο του GABA (γ-αμινοβουτυρικού οξέος) αλλά, χρησιμοποιείται και ως ψυχοδραστική ουσία, συνήθως ως παράνομο φάρμακο αναψυχής. Ο όρος «φάρμακο του κλαμπ» μπορεί να οριστεί ευρέως ως οποιαδήποτε ουσία που χρησιμοποιείται για την ενίσχυση κοινωνικών συναναστροφών. Τέτοιες ουσίες απαντώνται συνήθως σε rave ή παρόμοια πάρτι χορού και περιλαμβάνουν μεταξύ άλλων και το GHB. Αυτές οι ουσίες προκαλούν επικίνδυνες παρενέργειες, όπως παραισθήσεις, παράνοια, αμνησία και υπερθερμία. Επιπλέον, το GHB θεωρείται ουσία που χρησιμοποιείται για σεξουαλικά εγκλήματα λόγω της δράσης του ως κατασταλτικό. Οι ιατροδικαστικές και διωκτικές αρχές επομένως έχουν την ανάγκη ανίχνευσής του και την ακριβή ποσοτικοποίηση αυτής της ουσίας σε βιολογικά υγρά, ειδικά σε περιπτώσεις θανάτου ή ποινικών ερευνών σχετιζόμενων με σεξουαλικά εγκλήματα. Η εργασία αυτή συνοψίζει σημαντικές πληροφορίες σχετικά με τη δράση της ουσίας αυτής και παραθέτει κριτική ανασκόπηση των μεθόδων που εφαρμόζονται στη διεθνή βιβλιογραφία με τις τεχνικές της χρωματογραφίας– φασματομετρίας μαζών για τον προσδιορισμό της σε βιολογικά υλικά για σκοπούς εγκληματολογικής διερεύνησης
description: G-hydroxybutyric acid (GHB) that is a short chain hydroxy-acid is a naturally occurring neurotransmitter, is a precursor to GABA but also a psychoactive drug, commonly used as an illegal recreational drug. "Club medicine" can be defined as any substance used to enhance social conditions. Such substances are commonly found in rave or similar parties and include amongst others, gamma-hydroxybutyric acid (GHB). These substances have dangerous side effects such as hallucinations, paranoia, amnesia and hyperthermia. In addition, GHB is usually used in drug-facilitated sexual assaults due to its CNS depressive effects. For these reasons, forensic and regulatory authorities have the need for the detection and accurate quantification of this substance in biological fluids, especially in cases of death or criminal investigations. In this thesis all critical information concerning GHB biological effects and use is discussed and the literature on the analysis of biological fluids for the determination of GHB by chromatography – mass spectrometry is critically presented
Cumulant versus jet-like three-particle correlations
Creators: name: Ulery, Jason G.
name: Wang, Fuqiang
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Two-particle jet-like azimuthal correlations have revealed intriguing modifications to the away-side of high pt trigger particles in relativistic heavy-ion collisions. Three-particle jet-like azimuthal correlation and three-particle azimuthal cumulant have been analyzed in experiments in attempt to distinguish conical emission of jet-correlated particles from other physics mechanisms. We investigate the difference between three-particle jet-like correlation and three-particle cumulant in azimuth. We show, under the circumstance where the away-side two-particle correlation is relatively flat in azimuth and similar in magnitude to the azimuthal average of the two-particle correlation signal, that the three-particle cumulant cannot distinguish conical emission from other physics mechanisms. The three-particle jet-like correlation, on the other hand, retains its discrimination power.
description: 13 pages, 8 figures. published version
Σχολιασμένη μετάφραση αποσπασμάτων του διηγήματος Des Cobras à Paris του André Pieyre de Mandiargues
Creators: name: Κουφού, Μαρία Παναγιώτη
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Σχολιασμένη Μετάφραση
André Pieyre de Mandiargues
Σύγχρονη γαλλική πεζογραφία
Annotated translation
Contemporary French literature

description: Η παρούσα μεταπτυχιακή εργασία αποτελεί σχολιασμένη μετάφραση του διηγήματος Des Cobras à Paris του André Pieyre de Mandiargues (1909-1991). Στόχος της είναι να αναδείξει την ιδιότυπη μορφή ενός Γάλλου συγγραφέα του 20ού αιώνα, υπερρεαλιστή “δεύτερης γενιάς”, του οποίου το έργο παραμένει σχεδόν άγνωστο στο ελληνικό κοινό. Παράλληλα με τη μεταφραστική διαδικασία αναλύονται και δυσκολίες, τόσο λεξιλογικές, όσο και υφολογικές που χρειάστηκε να αντιμετωπιστούν. Ο πεζός λόγος του διηγήματος είναι λιτός, ωστόσο η χαρακτηριστική γραφή του συγγραφέα αναδεικνύεται μέσα από μια σειρά καλοδουλεμένων χαμηλόφωνων υφολογικών τεχνικών. Από τη στιγμή που λίγα έργα του André Pieyre de Mandiargues έχουν μεταφραστεί στην ελληνική γλώσσα, η μετάφραση του έργου αυτού αποτελεί μια πρόκληση για νέους μεταφραστές, ταυτόχρονα, όμως, δίνει και την ευκαιρία στο ελληνικό αναγνωστικό κοινό να γνωρίσει καλύτερα τον Γάλλο συγγραφέα.
description: The aim of the present thesis was to give an annotated translation of the novel Des Cobras à Paris by André Pieyre de Mandiargues (1909-1991). Its purpose was to reveal the author’s special writing, who is characterized as a second generation surrealist and whose works remain almost unknown to Greek readers. Furthermore, we analyzed the lexical and stylistic difficulties that derived during the process. The prose is quite simple, but the significant writing of André Pieyre de Mandiargues appears via elaborate stylistic techniques. This novel’s translation is considered to be a challenge for the young translators, and at the same time, it offers to Greek readers the chance to know better the work of this French author, who may not be that popular, but his work is of great value.
Refined Belief-Propagation Decoding of Quantum Codes with Scalar Messages
Creators: name: Kuo, Kao-Yueh
name: Lai, Ching-Yi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Information Theory (cs.IT)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Codes based on sparse matrices have good performance and can be efficiently decoded by belief-propagation (BP). Decoding binary stabilizer codes needs a quaternary BP for (additive) codes over GF(4), which has a higher check-node complexity compared to a binary BP for codes over GF(2). Moreover, BP decoding of stabilizer codes suffers a performance loss from the short cycles in the underlying Tanner graph. In this paper, we propose a refined BP algorithm for decoding quantum codes by passing scalar messages. For a given error syndrome, this algorithm decodes to the same output as the conventional quaternary BP but with a check-node complexity the same as binary BP. As every message is a scalar, the message normalization can be naturally applied to improve the performance. Another observation is that the message-update schedule affects the BP decoding performance against short cycles. We show that running BP with message normalization according to a serial schedule (or other schedules) may significantly improve the decoding performance and error-floor in computer simulation.
description: to be published in Proc. IEEE Global Commun. Conf. (GLOBECOM), 2020
Measurement of the Moments of the Photon Energy Spectrum in B -> X_s gamma Decays and Determination of |V_cb| and m_b at Belle
Creators: name: Belle Collaboration
name: Schwanda, C.
name: Urquijo, P.
name: Barberio, E.
name: Limosani, A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Using the previous Belle measurement of the inclusive photon energy in $B\to X_sγ$ decays, we determine the first and second moments of this spectrum for minimum photon energies in the $B$ meson rest frame ranging from 1.8 to 2.3 GeV. Combining these measurements with recent Belle data on the lepton energy and hadronic mass moments in $B\to X_c\ellν$ decays, we perform fits to theoretical expressions derived in the 1S and kinetic mass schemes and extract the magnitude of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $V_{cb}$, the $b$-quark mass and other non-perturbative parameters. In the 1S scheme analysis we find $|V_{cb}|=(41.56\pm 0.68(\mathrm{fit})\pm 0.08(τ_B))\times 10^{-3}$ and $m_b^\mathrm{1S}=(4.723\pm 0.055)$ GeV. In the kinetic scheme, we obtain $|V_{cb}|=(41.58\pm 0.69(\mathrm{fit})\pm 0.08(τ_B)\pm 0.58(\mathrm{th}))\times 10^{-3}$ and $m_b^\mathrm{kin}=(4.543\pm 0.075)$ GeV.
description: 19 pages, 9 figures, 12 tables
Peristaltic modes of single vortex in the Abelian Higgs model
Creators: name: Kojo, Toru
name: Suganuma, Hideo
name: Tsumura, Kyosuke
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Using the Abelian Higgs model, we study the radial excitations of single vortex and their propagation modes along the vortex line. We call such beyond-stringy modes {\it peristaltic} modes of single vortex. With the profile of the static vortex, we derive the vortex-induced potential, i.e., single-particle potential for the Higgs and the photon field fluctuations around the static vortex, and investigate the coherently propagating fluctuations which corresponds to the vibration of the vortex. We derive, analyze and numerically solve the field equations of the Higgs and the photon field fluctuations around the static vortex with various Ginzburg-Landau parameter $κ$ and topological charge $n$. Around the BPS value or critical coupling $κ^2$=1/2, there appears a significant correlation between the Higgs and the photon field fluctuations mediated by the static vortex. As a result, for $κ^2$=1/2, we find the characteristic {\it new} discrete pole of the peristaltic mode corresponding to the quasi-bound-state of coherently fluctuating fields and the static vortex. We investigate its excitation energy, correlation energy of coherent fluctuations, spatial distributions, and the resulting magnetic flux behavior in detail. Our investigation covers not only usual Type-II vortices with $|n|$=1 but also Type-I and Type-II vortices with $n\in Z$ for the application to various general systems where the vortex-like objects behave as the essential degrees of freedom.
description: 16pages, 12figures, minor changes, published in PRD
A physics-informed neural network for quantifying the microstructure properties of polycrystalline Nickel using ultrasound data
Creators: name: Shukla, Khemraj
name: Jagtap, Ameya D.
name: Blackshire, James L.
name: Sparkman, Daniel
name: Karniadakis, George Em
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We employ physics-informed neural networks (PINNs) to quantify the microstructure of a polycrystalline Nickel by computing the spatial variation of compliance coefficients (compressibility, stiffness and rigidity) of the material. The PINN is supervised with realistic ultrasonic surface acoustic wavefield data acquired at an ultrasonic frequency of 5 MHz for the polycrystalline material. The ultrasonic wavefield data is represented as a deformation on the top surface of the material with the deformation measured using the method of laser vibrometry. The ultrasonic data is further complemented with wavefield data generated using a finite element based solver. The neural network is physically-informed by the in-plane and out-of-plane elastic wave equations and its convergence is accelerated using adaptive activation functions. The overarching goal of this work is to infer the spatial variation of compliance coefficients of materials using PINNs, which for ultrasound involves the spatially varying speed of the elastic waves. More broadly, the resulting PINN based surrogate model shows a promising approach for solving ill-posed inverse problems, often encountered in the non-destructive evaluation of materials.
description: 18 pages, 5 figures
Alignment tests for low CMB multipoles
Creators: name: Abramo, L. Raul
name: Bernui, Armando
name: Ferreira, Ivan S.
name: Villela, T.
name: Wuensche, C. Alexandre
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the large scale anomalies in the angular distribution of the cosmic microwave background radiation as measured by WMAP using several tests. These tests, based on the multipole vector expansion, measure correlations between the phases of the multipoles as expressed by the directions of the multipole vectors and their associated normal planes. We have computed the probability distribution functions for 46 such tests, for the multipoles l=2-5. We confirm earlier findings that point to a high level of alignment between l=2 (quadrupole) and l=3 (octopole), but with our tests we do not find significant planarity in the octopole. In addition, we have found other possible anomalies in the alignment between the octopole and the l=4 (hexadecupole) components, as well as in the planarity of l=4 and l=5. We introduce the notion of a total likelihood to estimate the relevance of the low-multipoles tests of non-gaussianity. We show that, as a result of these tests, the CMB maps which are most widely used for cosmological analysis lie within the ~ 10% of randomly generated maps with lowest likelihoods.
description: References added, updated discussion on alignment with Ecliptic Plane. 12 Pages, 6 Figures. Results for additional maps, the normalized frequencies for the tests and a Mathematica Notebook that computes the tests can be found on http://fma.if.usp.br/~abramo/MVA.html
Integrated optics pockels cell high voltage sensor
Creators: name: Rahmatian, Farnoosh
Publisher: name: University of British Columbia
Year: 2008

description: In this thesis an integrated optics version of the Pockels cell, to be used for the measurement of high voltage in power transmission systems, is described. The operation of the sensor is based on the electro-optic effect in lithium niobate. The sensing head consists of a waveguide formed by diffusing a strip of titanium in a y-cut lithium niobate substrate. This waveguide (z-propagating) supports two orthogonal modes. An electric field, in which the sensor is immersed, alters the difference in the phase velocities of the two modes and, in turn, alters the polarization state at the output of the waveguide. Polarization maintain ingoptical fibres transmit light to the sensor head and interrogate its output. The electric field in which the sensor head is immersed can be detected by measuring the change in the polarization state at the output of the sensor. Also, some of the technological problems encountered in realizing an integrated optics Pockels cell (IOPC) have been addressed and overcome. The photolithographic fabrication of the waveguides, waveguide end preparation, permanent fibre to waveguide butt-coupling, and other fabrication steps have been successfully completed. Fully connectorized systems have been fabricated and tested to characterize the performance of the IOPC. Various device parameters such as intrinsic phase, half-waveelectric field, and extinction ratio have been measured for several devices. The effects of waveguide width and length on the performance of the sensor have been studied. Test results indicate that useful devices, well biased, need to be at least 5 mm long. The linearity of sensor response and noise in the measurements have been investigated. The test results show that the sensor is capable of metering high voltage AC signals with less than 0.3% error and,therefore, is likely to meet the power industry standards, such as those proposed by Erickson in 1992, for optical high voltage transducers. The stability of the sensor under various conditions has been explored. The piezoelectric resonances of the sensor heads and their effects on the bandwidths of the sensors have been examined. Sensors with large enough bandwidths have been fabricated which have successfully measured the IEC (InternationalElectrotechnical Commission) standard lightning impulses with 1.2 As front time and 50 Astail time. The results indicate that one IOPC can be used as a high voltage sensor in several applications such as metering high voltage AC signals, protection, and time-resolved-fault-location.
Hamiltonian Formulation of 5-dimensional Kaluza-Klein Theory
Creators: name: Lacquaniti, Valentino
name: Montani, Giovanni
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We analyze the consistency of the ADM approach to KK model; we prove that KK reduction commute with ADM splitting. This leads to a well defined Hamiltonian; we provide the outcome. The electromagnetic constraint is derived from a geometrical one and this result enforces the physical meaning of KK model. Moreover we study the role of the extra scalar field we have in our model; classical hints from geodesic motion and cosmological solutions suggest that the scalar field can be an alternative time variable in the relational point of view.
description: 5 pages, proceedings of the First Stueckelberg Workshop, to appear on "Il Nuovo Cimento B"
Simultaneous Deep Measurements of CO isotopologues and Dust Emission in Giant Molecular Clouds in the Andromeda Galaxy
Creators: name: Viaene, Sébastien
name: Forbrich, Jan
name: Lada, Charles J.
name: Petitpas, Glen
name: Faesi, Christopher
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present simultaneous measurements of emission from dust continuum at 230 GHz and the J=2-1 $^{12}$CO, $^{13}$CO and C$^{18}$O isotopologues at $\sim$ 15 pc resolution from individual Giant Molecular Clouds (GMCs) in the Andromeda galaxy (M31). These observations were obtained in an ongoing survey of this galaxy being conducted with the Submillimeter Array (SMA). Initial results describing the continuum and $^{12}$CO emission were published earlier. Here we primarily analyze the observations of $^{13}$CO and C$^{18}$O emission and compare them to the measurements of dust continuum and $^{12}$CO emission. We also report additional dust continuum and CO measurements from newly added GMCs to the M31 sample. We detect spatially resolved $^{13}$CO emission with high signal-to-noise in 31 objects. We find the extent of the $^{13}$CO emission to be nearly comparable to that of $^{12}$CO, typically covering 75\% of the area of the $^{12}$CO emission. We derive $^{13}$CO and C$^{18}$O abundances of 2.9 $\times 10^{-6}$ and 4.4 $\times 10^{-7}$ relative to H$_2$, respectively, by comparison with hydrogen column densities of the same regions derived from the dust continuum observations assuming a Milky Way gas-to-dust ratio. We find the isotopic abundance ratio [$^{13}$CO]/[C$^{18}$O] = 6.7$\pm$2.9 to be consistent with the Milky Way value (8.1). Finally, we derive the mass-to-light conversion factors for all three CO species to be $α_{12} = 8.7 \pm 3.9$, $α_{13} = 48.9 \pm 20.4$ and $α_{18} = 345^{+25}_{-31}$ M$_\odot$ (K km s$^{-1}$pc$^2$)$^{-1}$ for the J=2-1 transitions of $^{12}$CO, $^{13}$CO and C$^{18}$O, respectively.
description: 24 pages, 11 figures, accepted for publication in The Astrophysical Journal
Integrating rural development and biodiversity conservation in Central Romania
Creators: name: Mikulkac, Friederike
name: Newig, Jens
name: Horcea-Milcu, Andra-Ioana
name: Hartel, Tibur
name: Fischer, Jörn
Publisher: name: Universität Kassel
Year: 2013
Subjects: subject: biodiversity governance
subject: Common Agricultural Policy
subject: farmland biodiversity
subject: high nature value farming
subject: multi-level governance
subject: Romania
subject: Transylvania
subject: 320
subject: 570
subject: Rumänien
subject: Siebenbürgen
subject: Biodiversität
subject: Europäische Union
subject: Agrarpolitik
subject: Mehrebenen-Verflechtung

description: Allianzlizenz/Nationallizenz
The lifespan of classical solutions of semilinear wave equations with spatial weights and compactly supported data in one space dimension
Creators: name: Kitamura, Shunsuke
name: Morisawa, Katsuaki
name: Takamura, Hiroyuki
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: primary 35L71, secondary 35B44

description: This paper studies initial value problems for semilinear wave equations with spatial weights in one space dimension. The lifespan estimates of classical solutions for compactly supported data are established in all the cases of polynomial weights. The results are classified into two cases according to the total integral of the initial speed.
description: 31 pages. We have corrected typos in the first version
Color Tomography
Creators: name: Jain, Bhuvnesh
name: Connolly, Andrew
name: Takada, Masahiro
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Lensing tomography with multi-color imaging surveys can probe dark energy and the cosmological power spectrum. However accurate photometric redshifts for tomography out to high redshift require imaging in five or more bands, which is expensive to carry out over thousands of square degrees. Since lensing makes coarse, statistical use of redshift information, we explore the prospects for tomography using limited color information from two or three band imaging. With an appropriate calibration sample, we find that it is feasible to create up to four redshift bins using imaging data in just the g, r and i bands. We construct such redshift sub-samples from mock catalogs by clustering galaxies in color space and discarding regions with poorly-defined redshift distributions. The loss of galaxy number density decreases the accuracy of lensing measurements, but even losing half or more of the galaxies is not a severe loss for large area surveys. We estimate the errors on lensing power spectra and dark energy parameters with color tomography and discuss trade-offs in survey area and filter choice. We discuss the systematic errors that may change our conclusions, especially the information needed to tackle intrinsic alignments.
description: 23 pages, 10 figures. Matches version accepted for JCAP
Stereoscopic electron spectroscopy of solar hard X-ray flares with a single spacecraft
Creators: name: Kontar, Eduard P.
name: Brown, John C.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Hard X-ray (HXR) spectroscopy is the most direct method of diagnosing energetic electrons in solar flares. Here we present a technique which allows us to use a single HXR spectrum to determine an effectively stereoscopic electron energy distribution. Considering the Sun's surface to act as a 'Compton mirror' allows us to look at emitting electrons also from behind the source, providing vital information on downward-propagating particles. Using this technique we determine simultaneously the electron spectra of downward and upward directed electrons for two solar flares observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The results reveal surprisingly near-isotropic electron distributions, which contrast strongly with the expectations from the standard model which invokes strong downward beaming, including collisional thick-target model.
description: 7 pages, 3 figures, accepted to Astrophysical Journal Letters
A Node Formulation for Multistage Stochastic Programs with Endogenous Uncertainty
Creators: name: Pantuso, Giovanni
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: This paper introduces a node formulation for multistage stochastic programs with endogenous (i.e., decision-dependent) uncertainty. Problems with such structure arise when the choices of the decision maker determine a change in the likelihood of future random events. The node formulation avoids an explicit statement of non-anticipativity constraints, and as such keeps the dimension of the model sizeable. An exact solution algorithm for a special case is introduced and tested on a case study. Results show that the algorithm outperforms a commercial solver as the size of the instances increases.
Measurements of $\psip$ decays into $γK\bar{K}π$ and $γη\pipi$
Creators: name: Ablikim, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Radiative decays of the $\psip$ into $γK\bar{K}π$ and $γη\pipi$ final states are studied using 14 million $\psip$ events collected with the BESII detector. Branching fractions or upper limits on the branching fractions of $\psip$ and $\xcj$ decays are reported. No significant signal for $\etafl/\etafh$ is observed in the $K\bar{K}π$ or $η\pipi$ mass spectra, and upper limits on the branching fractions of $\psip\rarγ\etaf$, $\etaf\rar K\bar{K}π$ and $η\pipi$ are determined.
description: 11 pages, 12 figures, 4 table
Γενικευμένες Εκτιμητικές Εξισώσεις με εκτιμητές δεικτών διάταξης (rank) σε Γραμμικά Μικτά Μοντέλα για Δεδομένα κατά Συστάδες ή Ιεραρχικά
Creators: name: Αλεξανδρίδου, Ανδρονίκη Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Ιεραρχικά δεδομένα
Γραμμικό Μικτό Μοντέλο
Γενικευμένες Εκτιμητικές Εξισώσεις με εκτιμητές δεικτών διάταξης
Hierarchical data
Linear Mixed Model
Rank - Based Generalized Estimating Equations

description: Σκοπός της παρούσας εργασίας είναι η μελέτη ιεραρχικών δεδομένων (ή δεδομένων κατά συστάδες) μέσω των Γενικευμένων Εκτιμητικών Εξισώσεων με εκτιμητές δεικτών διάταξης. Στο πρώτο κεφάλαιο δίνεται η έννοια των πολυεπίπεδων (ή ιεραρχικών) μοντέλων, ώστε να αποσαφηνιστεί το εννοιολογικό πλαίσιο που χρησιμοποιείται κατά την ανάλυση των μεθοδολογιών. Στο δεύτερο κεφάλαιο γίνεται μια εισαγωγή στο Γραμμικό Μικτό Μοντέλο, που αποτελεί το βασικό μοντέλο παλινδρόμησης. Στη συνέχεια, στο τρίτο και τέταρτο κεφάλαιο, παρουσιάζεται το θεωρητικό πλαίσιο της μεθόδου Εκτίμησης με Δείκτες Διάταξης καθώς και των Γενικευμένων Εκτιμητικών Εξισώσεων, βάση του οποίου στο πέμπτο κεφάλαιο ορίζονται οι Γενικευμένες Εκτιμητικές Εξισώσεις με εκτιμητές δεικτών διάταξης. Στο έκτο κεφάλαιο παρουσιάζονται οι διαγνωστικοί έλεγχοι που πραγματοποιούνται για τον έλεγχο προσαρμογής διαφορετικών μεθόδων στα δεδομένα. Τέλος, στο έβδομο κεφάλαιο γίνεται εφαρμογή των Γενικευμένων Εκτιμητικών Εξισώσεων με εκτιμητές δεικτών διάταξης σε σύνολα δεδομένων που δεν πληρούν τις προϋποθέσεις του Γραμμικού Μικτού Μοντέλου. Οι εφαρμογές που παρουσιάζονται έχουν πραγματοποιηθεί μέσω του στατιστικού πακέτου R και τις βιβλιοθήκες nlme για το Γραμμικό Μικτό Μοντέλο και rlme για τις Γενικευμένες Εκτιμητικές Εξισώσεις με εκτιμητές δεικτών διάταξης.
description: The purpose of this thesis is the study of hierarchical (or clustered) data through Rank – Based Generalized Estimating Equations. The first chapter describes multilevel (or hierarchical) models in order to clarify the framework used in analyzing methodologies. The second chapter introduces the Linear Mixed Model, which is the basic regression model. Afterwards, in third and fourth chapters, the theoretical framework of the Rank – Based Estimation method as well as the Generalized Estimating Equations is presented, on the basis of which the Rank – Based Generalized Estimating Equations are defined in the fifth chapter. The sixth chapter presents the diagnostics for comparing fits. Finally, applications of Rank – Based Generalized Estimating Equations are carried out with the statistical package Rand the packages nlme for the Linear Mixed Model and rlme for the Rank – Based Generalized Estimating Equations.
A stringent upper limit on Be star fractions produced by binary interaction
Creators: name: Hastings, B.
name: Langer, N.
name: Wang, C.
name: Schootemeijer, A.
name: Milone, A. P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context. Binary evolution can result in fast-rotating stars, predicted to be observable as Be stars, through accretion of angular momentum during mass-transfer phases. Despite numerous observational evidence pointing to this possibly being the dominant Be formation channel, current models struggle to produce a satisfactory description of Be star populations. Aims. Given distinct uncertainties in detailed binary evolution calculations, we investigate a rigorous and model independent upper limit for the production of Be stars through binary interaction and aim to confront this limit with observations of Be stars in young star clusters. Methods. Using extreme assumptions, we calculate the number ratio of post-interaction to pre-interaction binary systems in a coeval population, which describes an upper limit to Be star formation through mass-transfer. A detailed comparison is made between our derived upper limit and relevant observations of Be stars, which allows us to probe several aspects of binary star physics. Results. We find that in coeval populations, binary interaction can at most account for one third of all main-sequence stars being Be stars. Near the cluster turn-off region, this limit appears to be realised in the clusters studied. Away from the turn-off, applying simple assumptions about which systems undergo unstable mass-transfer produces a good fit to the observed Be fraction as a function of mass. Conclusions. We find that assuming distinct physics, binary evolution alone can in principle match the high numbers of Be stars observed in open clusters. Whether the required binary physics is realised in nature remains to be investigated.
description: Accepted for publication in A&A
Molecular Hydrogen Emission from Protoplanetary Disks II. Effects of X-ray Irradiation and Dust Evolution
Creators: name: Nomura, H.
name: Aikawa, Y.
name: Tsujimoto, M.
name: Nakagawa, Y.
name: Millar, T. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Detailed models for the density and temperature profiles of gas and dust in protoplanetary disks are constructed by taking into account X-ray and ultraviolet (UV) irradiation from a central T Tauri star, as well as dust size growth and settling toward the disk midplane. The spatial and size distributions of dust grains in the disks are numerically computed by solving the coagulation equation for settling dust particles. The level populations and line emission of molecular hydrogen are calculated using the derived physical structure of the disks. X-ray irradiation is the dominant heating source of the gas in the inner disk region and in the surface layer, while the far UV heating dominates otherwise. If the central star has strong X-ray and weak UV radiation, the H2 level populations are controlled by X-ray pumping, and the X-ray induced transition lines could be observable. If the UV irradiation is strong, the level populations are controlled by thermal collisions or UV pumping, depending on the properties of the dust grains in the disks. As the dust particles evolve in the disks, the gas temperature at the disk surface drops because the grain photoelectric heating becomes less efficient, while the UV radiation fields become stronger due to the decrease of grain opacity. This makes the H2 level populations change from local thermodynamic equilibrium (LTE) to non-LTE distributions, which results in changes to the line ratios of H2 emission. Our results suggest that dust evolution in protoplanetary disks could be observable through the H2 line ratios. The emission lines are strong from disks irradiated by strong UV and X-rays and possessing small dust grains; such disks will be good targets in which to observe H2 emission.
description: 33 pages, accepted for publication in the Astrophysical Journal
Gauge covariant formulation of Wigner representation through deformational quantization --Application to Keldysh formalism with electromagnetic field--
Creators: name: Sugimoto, N.
name: Onoda, S.
name: Nagaosa, N.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We developed a gauge-covariant formulation of the non-equilibrium Green function method for the dynamical and/or non-uniform electromagnetic field by means of the deformational quantization method. Such a formulation is realized by replacing the Moyal product in the so-called Wigner space by the star product, and facilitates the order-by-order calculation of a gauge-invariant observable in terms of the electromagnetic field. An application of this formalism to the linear response theory is discussed.
Diffeomorphism, kappa transformations and the theory of non-linear realisations
Creators: name: Gomis, Joaquim
name: Kamimura, Kiyoshi
name: West, Peter
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We will show how the theory of non-linear realisations can be used to naturally incorporate world line diffeomorphisms and kappa transformations for the point particle and superpoint particle respectively. Similar results also hold for a general p-brane and super p-brane, however, we must in these cases include an additional Lorentz transformation.
description: 19pages, no figure. References are added and typos are corrected
Spin-wave dispersion in half-doped LaSrNiO
Creators: name: Yao, D. X.
name: Carlson, E. W.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Recent neutron scattering measurements reveal spin and charge ordering in the half-doped nickelate, La$_{3/2}$ Sr$_{1/2}$ NiO$_4$. Many of the features of the magnetic excitations have been explained in terms of the spin waves of diagonal stripes with weak single-ion anisotropy. However, an optical mode dispersing away from the (π,π) point was not captured by this theory. We show here that this apparent optical mode is a natural consequence of stripe twinning in a diagonal stripe pattern with a magnetic coupling structure which is two-fold symmetric, i.e. one possessing the same spatial rotational symmetry as the ground state.
description: 4 pages, 5 figures
A novel key pre-distribution scheme based on $μ$-PBIBD combinatorial design in the resource-constrained IoT network
Creators: name: Aski, Akbar Morshed
name: Javadi, Hamid Haj Seyyed
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: In a resource-constrained IoT network, end nodes like WSN, RFID, and embedded systems are used which have memory, processing, and energy limitations. One of the key distribution solutions in these types of networks is to use the key pre-distribution scheme, which accomplishes the key distribution operation offline before the resource-constrained devices deployment in the environment. Also, in order to reduce the shared key discovery computing and communication overhead, the use of combinatorial design in key pre-distribution has been proposed as a solution in recent years. In this study, a $μ$-PBIBD combinatorial design is introduced and constructed and the mapping of such design as a key pre-distribution scheme in the resource-constrained IoT network is explained. Through using such key pre-distribution scheme, more keys are obtained for communication between two devices in the IoT network. This means that there will be a maximum of q + 2 keys between the two devices in the network, where q is the prime power, that is, instead of having a common key for a direct secure connection, the two devices can have q + 2 common keys in their key chain. Accordingly, we would increase the resilience of the key pre-distribution scheme compared to the SBIBD, TD, Trade-KP, UKP *, RD * and 2-D $μ$-PBIBD designs. Keywords: resource-constrained IoT network; combinatorial design; $μ$-PBIBD; resilience.
description: in Persian language