cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Classification of topological insulators and superconductors in three spatial dimensions
Creators: name: Schnyder, Andreas P.
name: Ryu, Shinsei
name: Furusaki, Akira
name: Ludwig, Andreas W. W.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We systematically study topological phases of insulators and superconductors (SCs) in 3D. We find that there exist 3D topologically non-trivial insulators or SCs in 5 out of 10 symmetry classes introduced by Altland and Zirnbauer within the context of random matrix theory. One of these is the recently introduced Z_2 topological insulator in the symplectic symmetry class. We show there exist precisely 4 more topological insulators. For these systems, all of which are time-reversal (TR) invariant in 3D, the space of insulating ground states satisfying certain discrete symmetry properties is partitioned into topological sectors that are separated by quantum phase transitions. 3 of the above 5 topologically non-trivial phases can be realized as TR invariant SCs, and in these the different topological sectors are characterized by an integer winding number defined in momentum space. When such 3D topological insulators are terminated by a 2D surface, they support a number (which may be an arbitrary non-vanishing even number for singlet pairing) of Dirac fermion (Majorana fermion when spin rotation symmetry is completely broken) surface modes which remain gapless under arbitrary perturbations that preserve the characteristic discrete symmetries. In particular, these surface modes completely evade Anderson localization. These topological phases can be thought of as 3D analogues of well known paired topological phases in 2D such as the chiral p-wave SC. In the corresponding topologically non-trivial and topologically trivial 3D phases, the wavefunctions exhibit markedly distinct behavior. When an electromagnetic U(1) gauge field and fluctuations of the gap functions are included in the dynamics, the SC phases with non-vanishing winding number possess non-trivial topological ground state degeneracies.
description: 20 pages. Changed title, added two tables
The Geometry of The Entropic Principle and the Shape of the Universe
Creators: name: McInnes, Brett
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Ooguri, Vafa, and Verlinde have outlined an approach to two-dimensional accelerating string cosmology which is based on topological string theory, the ultimate objective being to develop a string-theoretic understanding of "creating the Universe from nothing". The key technical idea here is to assign *two different* Lorentzian spacetimes to a certain Euclidean space. Here we give a simple framework which allows this to be done in a systematic way. This framework allows us to extend the construction to higher dimensions. We find then that the general shape of the spatial sections of the newly created Universe is constrained by the OVV formalism: the sections have to be flat and compact.
description: 24 pages, 4 eps figures, improved exposition of Euclidean/Lorentzian smoothing
An approach to integrated ecosystem planning: an evaluation of the Minnewanka area plan, Banff National Park
Creators: name: Haid, Susan B
Publisher: name: University of British Columbia
Year: 2008

description: The Lake Minnewanka area is one of Banff National Park's most scenic and highly visited regions. Impacts such as the loss of significant montane habitat (characteristic of the Lower Bow Valley ecosystem) and social implications like crowding led to the need to develop a strategy for managing the area. The author worked with a planning team from the Canadian Parks Service(CPS) in Banff National Park (BNP) to develop the Minnewanka Area Plan. The primary purpose of the thesis is to evaluate the Minnewanka Area Plan to determine whether it effectively serves to maintain and enhance ecological integrity. A theoretical framework based on integrated ecosystem management was developed to evaluate the plan. Normative criteria from literature on recreational carrying capacity management and meaningful public participation were defined and applied to the plan. Overall, the plan was rated as successful according to the normative criteria. All of the criteria for an effective approach to carrying capacity management were considered and the plan reflected a fair and efficient public participation process. Stakeholder input influenced plan decisions to a high degree and several partnerships were developed through the planning process. Several inadequacies in the plan were identified through the evaluation. The adoption of an approach to ecosystem management called the Limits of Acceptable Change (LAC) was recommended as a guiding principle within the plan. The step-by-step LAC model was seen as overly complex in the context of the case study. Indicators and a monitoring program which are central to the LAC process were not defined as part of the plan. The evaluation of the public participation process indicated that stakeholder participation was high early in the planning process and reflected a partnership relationship where stakeholders shared the power of decision-making. During completion of the draft and final plan, the process became one of public consultation where the level and frequency of participation was lowered. Recommendations for improving the efficacy of the Minnewanka Area Plan are made within the thesis. A simpler approach to visitor and resource management which maintains the essential criteria of the LAC approach is suggested. Measures for maintaining a high level of public participation and improving the accountability of the CPS in decision-making are proposed. The normative criteria based on carrying capacity management and meaningful public participation processes are presented as a model for facilitating integrated ecosystem management in area planning within national parks.
Universality of a double scaling limit near singular edge points in random matrix models
Creators: name: Claeys, T.
name: Vanlessen, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 15A52; 33E17; 35Q15

description: We consider unitary random matrix ensembles Z_{n,s,t}^{-1}e^{-n tr V_{s,t}(M)}dM on the space of Hermitian n x n matrices M, where the confining potential V_{s,t} is such that the limiting mean density of eigenvalues (as n\to\infty and s,t\to 0) vanishes like a power 5/2 at a (singular) endpoint of its support. The main purpose of this paper is to prove universality of the eigenvalue correlation kernel in a double scaling limit. The limiting kernel is built out of functions associated with a special solution of the P_I^2 equation, which is a fourth order analogue of the Painleve I equation. In order to prove our result, we use the well-known connection between the eigenvalue correlation kernel and the Riemann-Hilbert (RH) problem for orthogonal polynomials, together with the Deift/Zhou steepest descent method to analyze the RH problem asymptotically. The key step in the asymptotic analysis will be the construction of a parametrix near the singular endpoint, for which we use the model RH problem for the special solution of the P_I^2 equation. In addition, the RH method allows us to determine the asymptotics (in a double scaling limit) of the recurrence coefficients of the orthogonal polynomials with respect to the varying weights e^{-nV_{s,t}} on \mathbb{R}. The special solution of the P_I^2 equation pops up in the n^{-2/7}-term of the asymptotics.
description: 32 pages, 3 figures
Genetic Code: A New Understanding of Codon - Amino Acid Assignment
Creators: name: Damjanovic, Zvonimir M.
name: Rakocevic, Miloje M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Quantitative Biology (q-bio.OT)
subject: Biomolecules (q-bio.BM)
subject: FOS: Biological sciences

description: In this work it is shown that 20 canonical amino acids (AAs) within genetic code appear to be a whole system with strict AAs positions; more exactly, with AAs ordinal number in three variants; first variant 00-19, second 00-21 and third 00-20. The ordinal number follows from the positions of belonging codons, i.e. their digrams (or doublets). The reading itself is a reading in quaternary numbering system if four bases possess the values within a specific logical square: A = 0, C = 1, G = 2, U = 3. By this, all splittings, distinctions and classifications of AAs appear to be in accordance to atom and nucleon number balance as well as to the other physico-chemical properties, such as hydrophobicity and polarity.
description: 25 Pages, 8 Tables, 5 Figures and 5 Surveys. The paper is submitting to GLASNIK of Montenegrin Academy of Science and Arts as a extended version of paper published in Ann. N.Y. Acad. Sci. 1048: 517-523 (2005)
Lithium abundance dispersion in metal-poor stars
Creators: name: Deal, Morgan
name: Richard, Olivier
name: Vauclair, Sylvie
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the main sequence

description: The formation and evolution of light elements in the Universe act as important cosmological constraints. The oldest stars of the Galaxy have long been assumed to display in their outer layers the primordial lithium abundance, although all studies of stellar physics proved that this abundance must have decreased with time. The primordial Li abundance deduced from the observations of the Cosmological Background is indeed larger than the maximum one observed in these stars. Recent observations gave evidence of a large Li abundance dispersion in very metal poor stars. During this presentation, we address the general question of the lithium abundance dispersion obtained from observations of metal-poor stars, and how the interplay of atomic diffusion and accretion of matter modifies the element abundances in these metal-poor stars. In particular, we focus on the hydrodynamic processes that could take place after accretion. We consider initial metallicities from [Fe/H]=-2.31 down to [Fe/H]=-5.45. We show that the observations of lithium dispersion, associated or not with carbon enrichment, are well accounted for in terms of accretion onto the metal-poor stars, with accreted masses smaller than a few Jupiter masses, when using a lithium initial abundance in accordance with the primordial lithium abundance obtained from latest BBN results.
Προσομοίωση και μελέτη απόδοσης του προτύπου WiMax
Creators: name: Τζιμτζίμη, Χριστίνα Βασιλείου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Αναλογία υποπλαισίων
Μανθάνον αυτόματο
Προσαρμοστικό μοντέλο
Sub-frames ratio
Learning Automaton
Adaptive model

description: Τα τελευταία χρόνια, η ραγδαία αύξηση νέων τεχνολογιών με στόχο την κατασκεύη όλο και πιο “έξυπνων” συσκευών επικοινωνίας, οι οποίες προσφέρουν όλο και περισσότερες δυνατότητες στους χρήστες, οδήγησε στην ολοένα αυξανόμενη ζήτηση για υψηλής ταχύτητας πρόσβαση όπου και αν βρίσκονται. Η πιο ιδανική λύση στην συγκεκριμένη περίπτωση ήταν η ασύρματη επικοινωνία. Έτσι λοιπόν αναπτύχθηκαν διάφορες τεχνολογίες για την ανάγκη αυτή με την πιο γνωστή σε όλους, αυτής του WiFi. Εξ αιτίας όμως διάφορων περιορισμών και μειονεκτημάτων που παρουσιάζει η συγκεριμένη τεχνολογία όπως το αρκετά υψηλό κόστος κατασκευής, την περιορισμένη κάλυψη εμβέλειας, τη δυσκαμψία στη συντήρηση και επέκταση του δικτύου δημιουργήθηκε η επιτακτική ανάγκη για ανακάλυψη και δημιουργία νέων τεχνολογιών οι οποίες θα καλύψουν τις παραπάνω αδυναμίες. Έτσι λοιπόν η IEEE, παρουσίασε το νεό πρότυπο 802.16, γνωστό και ως WiMax. Ο σκοπός της παρούσας διπλωματικής εργασίας είναι η μελέτη της απόδοσης του νέου αυτού προτύπου. Στα πλαίσια λοιπόν της εργασίας αυτής αναπτύχθηκε ένας προσομοιωτής με τη βοήθεια του εργαλείου προσομοίωσης OMNeT++, με τη χρήση του οποίου σχεδιάστηκαν διάφορα πειράματα που είχαν στόχο την μελέτη της απόδοσης του συγκεκριμένου προτύπου.
description: In recent years, the rapid growth of new technologies for the manufacture of increasingly "smart" communication devices, which offer more and more features to their users, has led to growing demand for high speed access wherever they are. The most ideal solution in this case was the wireless communication. So they developed a number of technologies for this need with the most known all of this WiFi. Owing, however various limitations and drawbacks of the specific technology such as relatively high manufacturing cost, limited coverage range, the stiffness in network maintenance and expansion created an urgent need for the discovery and development of new technologies which will meet the above weaknesses. So, IEEE presented the new standard 802.16, also known as WiMax, which brought the revolution in wireless communications. The purpose of this thesis is to study the performance of this new standard. As part of this work, therefore we developed a simulator using the simulation tool OMNeT ++, the use of which designed several experiments aimed to study the performance of this standard.
Pair invariant mass spectrum and polarization asymmetry in the event generation of gamma-ray conversions
Creators: name: Bernard, Denis
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: We examine the dielectron invariant mass spectrum and the variation of the polarization asymmetry as a function of that mass in the event generator of the five-dimensional Bethe-Heitler differential cross section of the conversion of linearly polarized photons that we have implemented recently as a Geant4 Physics Model. We compare the results obtained with simulated samples to analytical expressions. Studies of $b \to s γ$ decays at LHC and Belle II experiments could provide hints of physics beyond the standard model in flavor-changing neutral current processes; issues have been reported in the simulation of the properties of the background induced by genuine $γ$-ray conversions in their detectors. Our results demonstrate that using the five-dimensional model would help solve these issues.
description: v2 : complemented [7] with most recent LHCb result
HOME: Habitability Of Magnetized Environments
Creators: name: Alvarado-Gómez, Julián D.
name: Drake, Jeremy J.
name: Poppenhäger, Katja
name: Garraffo, Cecilia
name: Cohen, Ofer
name: Yadav, Rakesh K.
name: Fraschetti, Federico
name: Moschou, Sofia P.
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the main sequence
Stellar winds
Stellar magnetic fields
Planetary magnetosphere
Stellar mass loss
Interplanetary magnetic fields
Stellar activity
Exoplanets

description: The stellar magnetic field completely dominates the environment around late-type stars. It is responsible for generating the coronal high-energy radiation (Extreme Ultra-Violet and X-ray photons), the structure and strength of stellar winds, as well as for driving transient phenomena such as flares, coronal mass ejections and energetic particle events. Apart from their direct consequences on the star and its evolution, these phenomena will have strong effects on planetary systems via star-planet interactions and erosion of exoplanetary atmospheres. Understanding the Habitability of Magnetized Environments (HOME) is therefore a fundamental aspect in our search for life-supporting places in the Universe. In this context, the HOME project aims to perform a systematic characterization on how stellar magnetism affects the habitability conditions of exoplanetary systems and determine how such conditions change across spectral type and age. To achieve this objective, HOME employs surface magnetic field distributions of stars, in the form of Zeeman-Doppler Imaging (ZDI) observations and/or from high-end dynamosimulations, to construct physics-based models of the environments around stars and exoplanets. As an example, we summarize a HOME characterization of the Proxima Centauri system in this poster contribution.
description: {"references": ["Alvarado-G\u00f3mez et al. (2020). ApJL, 902, L9"]}
Successive phase transitions to antiferromagnetic and weak-ferromagnetic long-range orders in quasi-one-dimensional antiferromagnet Cu$_3$Mo$_2$O$_9$
Creators: name: Hamasaki, Tomoaki
name: Ide, Tomoyuki
name: Kuroe, Haruhiko
name: Sekine, Tomoyuki
name: Hase, Masashi
name: Tsukada, Ichiro
name: Sakakibara, Toshiro
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Investigation of the magnetism of Cu$_3$Mo$_2$O$_9$ single crystal, which has antiferromagnetic (AF) linear chains interacting with AF dimers, reveals an AF second-order phase transition at $T_{\rm N} = 7.9$ K. Although weak ferromagnetic-like behavior appears at lower temperatures in low magnetic fields, complete remanent magnetization cannot be detected down to 0.5 K. However, a jump is observed in the magnetization below weak ferromagnetic (WF) phase transition at $T_{\rm c} \simeq 2.5$ K when a tiny magnetic field along the a axis is reversed, suggesting that the coercive force is very weak. A component of magnetic moment parallel to the chain forms AF long-range order (LRO) below $T_{\rm N}$, while a perpendicular component is disordered above $T_{\rm c}$ at zero magnetic field and forms WF-LRO below $T_{\rm c}$. Moreover, the WF-LRO is also realized with applying magnetic fields even between $T_{\rm c}$ and $T_{\rm N}$. These results are explainable by both magnetic frustration among symmetric exchange interactions and competition between symmetric and asymmetric Dzyaloshinskii-Moriya exchange interactions.
description: 7 pages, 7 figures
ผลของโปรแกรมการกระตุ้นพัฒนาการอย่างมีส่วนร่วมของผู้ดูแลเด็กในศูนย์พัฒนาเด็กเล็กต่อพัฒนาการของเด็กอายุ 2-5 ปี
Creators: name: มนัสมีน เจะโนะ, รอฮานิ เจะอาแซ
Publisher: name: สำนักวิทยบริการ มหาวิทยาลัยสงขลานครินทร์ วิทยาเขตปัตตานี
Year: 2019
Subjects: การกระตุ้นพัฒนาการ, ผู้ดูแลเด็ก, พัฒนาการเด็ก, ศูนย์พัฒนาเด็กเล็ก, developmental stimulation, care takers, child development, child development centers

description: วารสารวิทยบริการ มหาวิทยาลัยสงขลานครินทร์, 30, 2, 80-88
Adatom incorporation and step crossing at the edges of 2D nanoislands
Creators: name: Filimonov, Sergey N.
name: Hervieu, Yuri Yu.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Adatom incorporation into the ``faceted'' steps bordering the 2D nanoislands is analyzed. The step permeability and incorporation coefficients are derived for some typical growth situations. It is shown that the step consisting of equivalent straight segments can be permeable even in the case of fast egde migration if there exist factors delaying creation of new kinks. The step consisting of alternating rough and straight segments may be permeable if there is no adatom transport between neighboring segments through the corner diffusion.
description: 3 pages, one figure
Transient Nucleation near the Mean-Field Spinodal
Creators: name: Schweiger, A. O.
name: Barros, K.
name: Klein, W.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Nucleation is considered near the pseudospinodal in a one-dimensional $ϕ^4$ model with a non-conserved order parameter and long-range interactions. For a sufficiently large system or a system with slow relaxation to metastable equilibrium, there is a non-negligible probability of nucleation occurring before reaching metastable equilibrium. This process is referred to as transient nucleation. The critical droplet is defined to be the configuration of maximum likelihood that is dynamically balanced between the metastable and stable wells. Time-dependent droplet profiles and nucleation rates are derived, and theoretical results are compared to computer simulation. The analysis reveals a distribution of nucleation times with a distinct peak characteristic of a nonstationary nucleation rate. Under the quench conditions employed, transient critical droplets are more compact than the droplets found in metastable equilibrium simulations and theoretical predictions.
description: 7 Pages, 5 Figures
On occurrence of spectral edges for periodic operators inside the Brillouin zone
Creators: name: Harrison, J. M.
name: Kuchment, P.
name: Sobolev, A.
name: Winn, B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 35P99, 47F05, 58J50, 81Q10

description: The article discusses the following frequently arising question on the spectral structure of periodic operators of mathematical physics (e.g., Schroedinger, Maxwell, waveguide operators, etc.). Is it true that one can obtain the correct spectrum by using the values of the quasimomentum running over the boundary of the (reduced) Brillouin zone only, rather than the whole zone? Or, do the edges of the spectrum occur necessarily at the set of ``corner'' high symmetry points? This is known to be true in 1D, while no apparent reasons exist for this to be happening in higher dimensions. In many practical cases, though, this appears to be correct, which sometimes leads to the claims that this is always true. There seems to be no definite answer in the literature, and one encounters different opinions about this problem in the community. In this paper, starting with simple discrete graph operators, we construct a variety of convincing multiply-periodic examples showing that the spectral edges might occur deeply inside the Brillouin zone. On the other hand, it is also shown that in a ``generic'' case, the situation of spectral edges appearing at high symmetry points is stable under small perturbations. This explains to some degree why in many (maybe even most) practical cases the statement still holds.
description: 25 pages, 10 EPS figures. Typos corrected and a reference added in the new version
Giant white-light flares on fully convective stars occur at high latitudes
Creators: name: Ilin, Ekaterina
name: Poppenhaeger, Katja
name: Schmidt, Sarah Jane
name: Järvinen, Silva P.
name: Newton, Elisabeth R.
name: Alvarado-Gómez, Julián D.
name: Pineda, J. Sebastian
name: Davenport, James R. A.
name: Oshagh, Mahmoudreza
name: Ilyin, Ilya
Publisher: name: Zenodo
Year: 2021
Subjects: Very low mass stars
stellar activity
flares
stellar rotation
stellar magnetic fields
low-mass stars

description: In a systematic analysis of fully convective stars observed with TESS, we detected four stars that displayed giant flares that were modulated in brightness by the stars' rapid rotation. The morphology of the modulation allowed us to directly localize these flares between 55° and 81° latitude on the stellar surface, far higher than typical solar flare latitudes. These findings are a. evidence that strong magnetic fields tend to emerge close to the stellar rotational poles for fully convective stars, and b. suggest that the impact of flares on the habitability of exoplanets around small stars could be weaker than previously thought.
description: {"references": ["Davenport et al. (2014), ApJ, 797, 122"]}
Μπορώ, μπορείς, μπορούμε… στον κόσμο της τέχνης αν βρεθούμε»_ Η απελευθερωτική δυναμική της τέχνης
Creators: name: Αλαγιαλόγλου, Κλεοπάτρα Βασιλείου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Τέχνη-Ρώσικη Πρωτοπορία
Μουσειοπαιδαγωγικό
Art-Russian avant-garde
Museum education

description: Σκοπός της διατριβής ήταν o επαναπροσδιορισμόw των μεθόδων αντίληψης και σύνθεσης της αρχιτεκτονικής μουσειακής πραγματικότητας. Η αρχιτεκτονική οφείλει να συνδιαλέγεται πλέον με άλλα επιστημονικά πεδία, αποκτώντας νέες προσλαμβάνουσες που της προσδίδουν κοινωνικό και ανθρωποκεντρικό χαρακτήρα. Στο πλαίσιο της παρούσας διπλωματικής σχεδιάστηκε μία έκθεση με παιδικά έργα - δημιουργίες του μουσειοπιαδαγωγικού προγράμματος «Μπορώ, μπορείς, μπορούμε… στον κόσμο της τέχνης αν βρεθούμε», με στόχο την έμμεση πραγματοποίηση ενός εκπαιδευτικού προγράμματος για ενήλικες μέσα από το βίωμα. Τα παιδικά έργα εκφράζουν την απλοποίηση των εννοιών και του κόσμου στο μυαλό του παιδιού, κάτι που δυσκολεύει εμφανώς και έντονα τον ενήλικα. Η αφήγηση της έκθεσης ξετυλίγεται, προκαλώντας και προσκαλώντας το θεατή να απελευθερώσει το μυαλό και τη φαντασία του και να ταξιδέψει λυτρωτικά και σχεδόν ψυχοθεραπευτικά στον κόσμο της τέχνης και των πολλαπλών υποκειμενικών ερμηνειών μέσα από πλήθος χρωμάτων και σχημάτων.
description: The aim of the present thesis was the redefinition of the conception and composition methods in the architectonical design of contemporary museum reality. Architecture needs to collaborate and open dialog with multiple scientific fields, adapting alternative approaches with more social and anthropocentric perspective. Important part of this thesis was the design of an childern’s art works exhibition, that have originally been created during the museum educational program “I can, you can, we all can....if we meet in the world of Art”. My main goal was the planning and creation of an educational program for adults through personal experience. Children’s pieces of art represent the ultimate simplification of the world and its deeper meanings, something that seems to be very hard understood by any adult. The exhibition’s narration is based on the liberation of the visitor’s mind and his/her imagination, in order to start a redemptive journey, almost as a psychotherapy in the world of art and the multiple objective approaches of the colors and the drawing’s shapes.
description: Σε συνεργασία με το Παιδαγωγικό Τμήμα Δημοτικής Εκπαίδευσης (Πανεπιστήμιο Δυτικής Μακεδονίας)
Memory-efficient Speech Recognition on Smart Devices
Creators: name: Venkatesh, Ganesh
name: Valliappan, Alagappan
name: Mahadeokar, Jay
name: Shangguan, Yuan
name: Fuegen, Christian
name: Seltzer, Michael L.
name: Chandra, Vikas
Publisher: name: arXiv
Year: 2021
Subjects: subject: Sound (cs.SD)
subject: Computation and Language (cs.CL)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Recurrent transducer models have emerged as a promising solution for speech recognition on the current and next generation smart devices. The transducer models provide competitive accuracy within a reasonable memory footprint alleviating the memory capacity constraints in these devices. However, these models access parameters from off-chip memory for every input time step which adversely effects device battery life and limits their usability on low-power devices. We address transducer model's memory access concerns by optimizing their model architecture and designing novel recurrent cell designs. We demonstrate that i) model's energy cost is dominated by accessing model weights from off-chip memory, ii) transducer model architecture is pivotal in determining the number of accesses to off-chip memory and just model size is not a good proxy, iii) our transducer model optimizations and novel recurrent cell reduces off-chip memory accesses by 4.5x and model size by 2x with minimal accuracy impact.
20-100 keV properties of cataclysmic variables detected in the INTEGRAL/IBIS survey
Creators: name: Barlow, E. J.
name: Knigge, C.
name: Bird, A. J.
name: Dean, A. J.
name: Clark, D. J.
name: Hill, A. B.
name: Molina, M.
name: Sguera, V.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Analysis of INTEGRAL/IBIS survey observations has revealed that the rare intermediate polar and asynchronous polar cataclysmic variables are consistently found to emit in the 20-100 keV energy band, whereas synchronous polars and the common non-magnetic CVs rarely do so. From the correlation of a candidate INTEGRAL/IBIS survey source list with a CV catalogue, 15 CV detections by IBIS have been established including a new INTEGRAL source IGR J06253+7334. The properties of these sources and 4 additional CV candidates are discussed in the context of their 20-100 keV emission characteristics and we conclude that the INTEGRAL mission is an important tool in the detection of new magnetic CV systems. Furthermore, analysis of the time-averaged spectra of CVs detected by INTEGRAL indicate that although there is little difference between the spectral slopes of the different sub-types, intermediate polars may be considerably more luminous than polars in the soft gamma-ray regime. We also present the detection of an unusual high-energy burst from V1223 Sgr discovered by inspection of the IBIS light-curve. Additionally, we have compared the IBIS and optical AAVSO light-curves of SS Cyg and extracted IBIS spectra during single periods of optical outburst and quiescence. We find that the 20-100 keV flux is an order of magnitude greater during optical quiescence. This is in agreement with previous studies which show that the hard X-ray component of SS Cyg is suppressed during high accretion states
description: 9 pages, 6 figures, 4 tables; accepted for publication in MNRAS
Texture synthesis and nonparametric resampling of random fields
Creators: name: Levina, Elizaveta
name: Bickel, Peter J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62M40 (Primary) 62G09 (Secondary)

description: This paper introduces a nonparametric algorithm for bootstrapping a stationary random field and proves certain consistency properties of the algorithm for the case of mixing random fields. The motivation for this paper comes from relating a heuristic texture synthesis algorithm popular in computer vision to general nonparametric bootstrapping of stationary random fields. We give a formal resampling scheme for the heuristic texture algorithm and prove that it produces a consistent estimate of the joint distribution of pixels in a window of certain size under mixing and regularity conditions on the random field. The joint distribution of pixels is the quantity of interest here because theories of human perception of texture suggest that two textures with the same joint distribution of pixel values in a suitably chosen window will appear similar to a human. Thus we provide theoretical justification for an algorithm that has already been very successful in practice, and suggest an explanation for its perceptually good results.
description: Published at http://dx.doi.org/10.1214/009053606000000588 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Uncertainty functions of the open quantum harmonic oscillator in the Lindblad theory
Creators: name: Isar, A.
name: Scheid, W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In the framework of the Lindblad theory for open quantum systems, we derive closed analytical expressions of the Heisenberg and Schrödinger generalized uncertainty functions for a particle moving in a harmonic oscillator potential. The particle is initially in an arbitrary correlated coherent state, and interacts with an environment at finite temperature. We describe how the quantum and thermal fluctuations contribute to the uncertainties in the canonical variables of the system and analyze the relative importance of these fluctuations in the evolution of the system. We show that upon contact with the bath the system evolves from a quantum-dominated to a thermal-dominated state in a time that is of the same order as the decoherence time calculated in other models in the context of transitions from quantum to classical physics.
description: 23 pages, 8 figures
People are Strange: Έρευνα κοινού για την έκθεση “Digital Revolution”
Creators: name: Αργυριάδου, Λουκία Θεόδωρου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Έρευνα Κοινού
Έκθεση “Digital Revolution”
Στέγη του Ιδρύματος Ωνάση
Public Research
Exhibition “Digital Revolution”
Onassis Cultural Centre

description: Η Έρευνα Κοινού είναι ένα σημαντικό μεθοδολογικό εργαλείο, εξαιρετικά χρήσιμο για την αναγνώριση και τη διεύρυνση του κοινού ενός πολιτιστικού οργανισμού, καθώς και για την αξιολόγηση και συνεχή βελτίωση των υπηρεσιών και δραστηριοτήτων του. Υπάρχουν δύο κύριες μέθοδοι κοινωνικής έρευνας, η ποσοτική και η ποιοτική έρευνα κοινού, που διαφέρουν ως προς την επιστημολογική τους κατεύθυνση και το αντικείμενο που εξετάζουν. Η ποσοτική μέθοδος έρευνας, εξετάζει ένα μέρος του πληθυσμού και με την βοήθεια εργαλείων στατιστικής ανάλυσης, εξάγει συμπεράσματα που γενικεύονται για όλο τον πληθυσμό. Η ποιοτική μέθοδος έρευνας, εξετάζει τα κοινωνικά φαινόμενα και τις αιτίες πίσω από τις απαντήσεις των κοινωνικών υποκειμένων. Παρά τις φιλοσοφικές και μεθοδολογικές διαφορές, στη σύγχρονη κοινωνική έρευνα κρίνεται χρήσιμος ο συγκερασμός των δύο μεθόδων, για την ολιστική προσέγγιση ενός κοινωνικού φαινομένου. Μέσα από τη μελέτη περίπτωσης της έρευνας κοινού, που υλοποιήθηκε τον Δεκέμβρη του 2015 για την έκθεση «Digital Revolution» της Στέγης Γραμμάτων και Τεχνών, με την χρήση και των δύο μεθόδων, ξετυλίγουμε τα στάδια σχεδιασμού και υλοποίησης μίας έρευνας κοινού και προχωρούμε στην επεξεργασία και ανάλυση των δεδομένων, για την εξαγωγή συμπερασμάτων τόσο για τον ίδιο τον οργανισμό όσο και για την χρησιμότητα της έρευνας.
description: Public Research is a significant systemic tool, extremely useful for the public investigation of a cultural organization, as well as for both the service and activities evaluation and constant improvement. There are two main methods of public research, the Quantitative and the Qualitative public research. The two methods differ in not only their epistemological stance but also the inspecting object. Quantitative public research focuses on a part of the population to draw conclusions for the whole population through the tools of statistical analysis. Qualitative public research focuses on social phenomena and causes through the answers of the social subjects. Despite the philosophical and methodological differences, in modern public research, it is believed that the combination of the two methods is useful in the holistic approach of a social phenomenon.Through the case study of public research, implemented in December 2015 for the exhibition «Digital Revolution» of the Onassis Cultural Centre, using both methods, we unfold the stages of planning and implementation of a public research and proceed to data processing and analysis, to draw conclusions regarding the organization as well as about the necessity of the research.
description: Σε συνεργασία με το Παιδαγωγικό Δημοτικής Εκπαίδευσης (Πανεπιστήμιο Δυτικής Μακεδονίας)
Statistical analysis of fireballs: Seismic signature survey
Creators: name: Neidhart, T.
name: Miljković, K.
name: Sansom, E. K.
name: Devillepoix, H. A. R.
name: Kawamura, T.
name: Dimech, J. -L.
name: Wieczorek, M. A.
name: Bland, P. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: Fireballs are infrequently recorded by seismic sensors on the ground. If recorded, they are usually reported as one-off events. This study is the first seismic bulk analysis of the largest single fireball data set, observed by the Desert Fireball Network (DFN) in Australia in the period 2014-2019. The DFN typically observes fireballs from cm-m scale impactors. We identified 25 fireballs in seismic time series data recorded by the Australian National Seismograph Network (ANSN). This corresponds to 1.8% of surveyed fireballs, at the kinetic energy range of 10$^6$ to 10$^{10}$ J. The peaks observed in the seismic time series data were consistent with calculated arrival times of the direct airwave or ground-coupled Rayleigh wave caused by shock waves by the fireball in the atmosphere (either due to fragmentation or the passage of the Mach cone). Our work suggests that identification of fireball events in the seismic time series data depends both on physical properties of a fireball (such as fireball energy and entry angle in the atmosphere) and the sensitivity of a seismic instrument. This work suggests that fireballs are likely detectable within 200 km direct air distance between a fireball and seismic station, for sensors used in the ANSN. If each DFN observatory had been accompanied by a seismic sensor of similar sensitivity, 50% of surveyed fireballs could have been detected. These statistics justify the future consideration of expanding the DFN camera network into the seismic domain.
description: accepted for publication in PASA
Explicit high-order generalized-$α$ methods for isogeometric analysis of structural dynamics
Creators: name: Behnoudfar, Pouria
name: Loli, Gabriele
name: Reali, Alessandro
name: Sangalli, Giancarlo
name: Calo, Victor M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We propose a new family of high-order explicit generalized-$α$ methods for hyperbolic problems with the feature of dissipation control. Our approach delivers $2k,\, \left(k \in \mathbb{N}\right)$ accuracy order in time by solving $k$ matrix systems explicitly and updating the other $2k$ variables at each time-step. The user can control the numerical dissipation in the discrete spectrum's high-frequency regions by adjusting the method's coefficients. We study the method's spectrum behaviour and show that the CFL condition is independent of the accuracy order. The stability region remains invariant while we increase the accuracy order. Next, we exploit efficient preconditioners for the isogeometric matrix to minimize the computational cost. These preconditioners use a diagonal-scaled Kronecker product of univariate parametric mass matrices; they have a robust performance with respect to the spline degree and the mesh size, and their decomposition structure implies that their application is faster than a matrix-vector product involving the fully-assembled mass matrix. Our high-order schemes require simple modifications of the available implementations of the generalized-$α$ method. Finally, we present numerical examples demonstrating the methodology's performance regarding single- and multi-patch IGA discretizations.
Are we observing a NSC in course of formation in the NGC 4654 galaxy?
Creators: name: Schiavi, Riccardo
name: Capuzzo-Dolcetta, Roberto
name: Georgiev, Iskren Y.
name: Arca-Sedda, Manuel
name: Mastrobuono-Battisti, Alessandra
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use direct $N$-body simulations to explore some possible scenarios for the future evolution of two massive clusters observed toward the center of NGC\,4654, a spiral galaxy with mass similar to that of the Milky Way. Using archival HST data, we obtain the photometric masses of the two clusters, $M=3\times 10^5$ M$_\odot$ and $M=1.7\times 10^6$ M$_\odot$, their half-light radii, $R_{\rm eff}\sim4$ pc and $R_{\rm eff} \sim 6$ pc, and their projected distances from the photometric center of the galaxy (both $<22$ pc). The knowledge of the structure and separation of these two clusters ($\sim 24$ pc) provides a unique view for studying the dynamics of a galactic central zone hosting massive clusters. Varying some of the unknown clusters orbital parameters, we carry out several $N$-body simulations showing that the future evolution of these clusters will inevitably result in their merger. We find that, mainly depending on the shape of their relative orbit, they will merge into the galactic center in less than 82 Myr. In addition to the tidal interaction, a proper consideration of the dynamical friction braking would shorten the merging times up to few Myr. We also investigate the possibility to form a massive NSC in the center of the galaxy by this process. Our analysis suggests that for low eccentricity orbits, and relatively long merger times, the final merged cluster is spherical in shape, with an effective radius of few parsecs and a mass within the effective radius of the order of $10^5\,\mathrm{M_{\odot}}$. Because the central density of such a cluster is higher than that of the host galaxy, it is likely that this merger remnant could be the likely embryo of a future NSC.
description: 10 Pages, 11 Figures, 2 Tables. Published in MNRAS
Simultaneous cooling and entanglement of mechanical modes of a micromirror in an optical cavity
Creators: name: Genes, Claudiu
name: Vitali, David
name: Tombesi, Paolo
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Laser cooling of a mechanical mode of a resonator by the radiation pressure of a detuned optical cavity mode has been recently demonstrated by various groups in different experimental configurations. Here we consider the effect of a second mechanical mode with a close, but different resonance frequency. We show that the nearby mechanical resonance is simultaneously cooled by the cavity field, provided that the difference between the two mechanical frequencies is not too small. When this frequency difference becomes smaller than the effective mechanical damping of the secondary mode, the two cooling processes interfere destructively and cavity cooling is suppressed in the limit of identical mechanical frequencies. We show that also the entanglement properties of the steady state of the tripartite system crucially depend upon on the difference between the two mechanical frequencies. If the latter is larger than the effective damping of the second mechanical mode, the state shows fully tripartite entanglement and each mechanical mode is entangled with the cavity mode. If instead the frequency difference is smaller, the steady state is a two-mode biseparable state, inseparable only when one splits the cavity mode from the two mechanical modes. In this latter case, the entanglement of each mechanical mode with the cavity mode is extremely fragile with respect to temperature.
description: submitted to NJP
Νοηματικός μουσειολογικός προγραμματισμός και σχεδιασμός περιοδικής έκθεσης των κειμηλίων της Μονής Αγίου Γεωργίου Περιστερεώτα
Creators: name: Καλπατσινίδου, Ευδοξία Απόστολου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Κειμήλια
Μονή Αγίου Γεωργίου Περιστερεώτα
Πόντος
Relics
Saint George Peristerota Monastery
Pontos

description: Αντικείμενο της παρούσας είναι η προσέγγιση των κειμηλίων της Μονής του Αγίου Περιστερεώτα στη Γαλίαινα του Πόντου, με ζητούμενο το νοηματικό μουσειολογικό προγραμματισμό και σχεδιασμό περιοδικής έκθεσης στο Διοικητήριο του Στρατοπέδου Κόδρα στην Καλαμαριά. Το περιεχόμενο διαιρείται σε τρία μεγάλα μέρη, στη μουσειολογική αναγνώριση, στο μουσειολογικό προγραμματισμό και τέλος στο μουσειολογικό σχεδιασμό. Αρχικά επιχειρείται να εντοπιστεί, να καταγραφεί και να αναλυθεί όλο εκείνο το πλήθος δεδομένων και παραμέτρων που απαιτείται να αξιολογηθούν και να ληφθούν υπόψη ώστε να καταστεί επιτυχημένο το εγχείρημα. Το προϊόν της ανάλυσης όλων των παραμέτρων του προγραμματισμού οδηγεί στο επόμενο μέρος, το μουσειολογικό σχεδιασμό. Εκεί, λαμβάνοντας υπόψη τα αποστάγματα του προγραμματισμού που προηγήθηκε, συγκεκριμενοποιούνται η κεντρική ιδέα της επικείμενης έκθεσης, το μουσειολογικό σκεπτικό και η πορεία της αφήγησης.
description: The objective of this dissertation is to approach the relics of Saint George Peristereota Monastery in Galliaina of Pontos, aiming at the conceptual museological programming and exhibition design for periodical exhibition at the Military Headquarters of Kodra in Kalamaria. The content is divided in three main parts, the museological recognition, the museological programming and finally the museological design. Firstly, we seek to spot, identify and analyze all the amount of information and parameters that are required to be evaluated and taken into account in order for this enterprise to be successful. The product of the analysis of all the programming parameters leads to the next part, the museological design. In this part, taking into account the distillations of programming that preceded it, the main idea of the impending exhibition, the museological rationale and the route of the narative are being particularized.
description: Σε συνεργασία με το Παιδαγωγικό Τμήμα Δημοτικής Εκπαίδευσης (Πανεπιστήμιο Δυτικής Μακεδονίας)
News Article Retrieval in Context for Event-centric Narrative Creation
Creators: name: Voskarides, Nikos
name: Meij, Edgar
name: Sauer, Sabrina
name: de Rijke, Maarten
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: Writers such as journalists often use automatic tools to find relevant content to include in their narratives. In this paper, we focus on supporting writers in the news domain to develop event-centric narratives. Given an incomplete narrative that specifies a main event and a context, we aim to retrieve news articles that discuss relevant events that would enable the continuation of the narrative. We formally define this task and propose a retrieval dataset construction procedure that relies on existing news articles to simulate incomplete narratives and relevant articles. Experiments on two datasets derived from this procedure show that state-of-the-art lexical and semantic rankers are not sufficient for this task. We show that combining those with a ranker that ranks articles by reverse chronological order outperforms those rankers alone. We also perform an in-depth quantitative and qualitative analysis of the results that sheds light on the characteristics of this task.
description: ICTIR 2021
Determination of Fundamental Properties of M-dwarfs
Creators: name: Iyer, Aishwarya
name: Line, Michael
name: Muirhead, Philip
name: Fortney, Jonathan
name: Gharib-Nezhad, Ehsan
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the Main Sequence

description: Abstract About 70% of stars in the Milky Way galaxy are M-dwarfs. They span a range of low masses (0.08 - 0.6 solar mass), have faint luminosities (less than 0.05 solar luminosity), and temperatures ranging between 2500 K - 4000 K, facilitating molecule formation throughout their atmospheres. Standard stellar analysis methods to accurately characterize them have thus far proved challenging—in not correctly accounting for vast variations in their atmospheric structures. Our modeling framework will determine fundamental atmospheric properties of M-dwarfs with a two-pronged approach: a physically motivated self-consistent radiative-convective model grid with up-to-date opacities, constrained by thermo-chemical and hydrostatic equilibrium, radiative and convective transport as well as a data-driven Bayesian retrieval technique. We leverage the broadband molecular absorption features occurring in low-resolution M-dwarf spectra (from SpeX Prism Library) and use them to our advantage in acquiring robust constraints on the effective temperature, surface gravity and bulk chemical properties of M-dwarf atmospheres. Our approach lies in the interface between the standard self-consistent prescription for modeling stellar atmospheres and an assumption-free data-driven retrieval method, where new physical intuition can be obtained about our understanding of low-mass stars.
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