cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Αποτίμηση σεισμικής τρωτότητας σύμμικτων κτιρίων με προηγμένες μεθόδους δυναμικής ανάλυσης
Creators: name: Χατζηλίας Ιωσήφ
Publisher: name: Technical University of Crete
Year: 2010

description: Κεφ. 1: Σύμμικτες κατασκευές -- Κεφ. 2: Γενικές αρχές αντισεισμικού σχεδιασμού -- Κεφ. 3: Μέθοδος επαυξητικής δυναμικής ανάλυσης (IDA) -- Κεφ. 4: Σεισμική αποτίμηση κατασκευών -- Κεφ. 5: Αριθμητικά αποτελέσματα
Planetesimals Around Stars with TESS (PAST): II. An M Dwarf "Dipper" Star with a Long-Lived Disk in the TESS Continuous Viewing Zone
Creators: name: Gaidos, Eric
name: Mann, Andrew W.
name: Rojas-Ayala, Bárbara
name: Feiden, Gregory A.
name: Wood, Mackenna L.
name: Narayanan, Suchitra
name: Ansdell, Megan
name: Jacobs, Tom
name: LaCourse, Daryll
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Studies of T Tauri disks inform planet formation theory; observations of variability due to occultation by circumstellar dust are a useful probe of unresolved, planet-forming inner disks, especially around faint M dwarf stars. We report observations of 2M0632, an M dwarf member of the Carina young moving group that was observed by TESS over two one-year intervals. The combined light curve contains >300 dimming events, each lasting a few hours, and as deep as 40% (0.55 magnitudes). These stochastic events are correlated with a distinct, stable 1.86-day periodic signal that could be stellar rotation. Concurrent ground-based, multi-band photometry show reddening consistent with ISM-like dust. The star's excess emission in the infrared and emission lines in optical and infrared spectra, reveal a T Tauri-like accretion disk around the star. We confirm membership of 2M0632 in the Carina group by a Bayesian analysis of its Galactic space motion and position. We combine stellar evolution models with Gaia photometry and constraints on Teff, luminosity, and the absence of detectable lithium in the photosphere to constrain the age of the group and 2M0632 to 40-60 Myr, consistent with earlier estimates. 2M0632 joins a handful of long-lived disks which challenge the canon that disk lifetimes are <10 Myr. All known examples surround M dwarfs, suggesting that lower X-ray/UV irradiation and slower photoevaporation by these stars can dramatically affect disk evolution. The multi-planet systems spawned by long-lived disks probably experienced significant orbital damping and migration into close-in, resonant orbits, and perhaps represented by the TRAPPIST-1 system.
description: Accepted to MNRAS 2022 April 25
Randzeichnungen einer Koberger-Inkunabel und das Erlanger Musterblatt mit kämpfenden Reihern
Creators: name: Waetzoldt, Stephan
Publisher: name: Anzeiger des Germanischen Nationalmuseums
Year: 2017

description: Anzeiger des Germanischen Nationalmuseums, 1963: Anzeiger des Germanischen Nationalmuseums
Supplementary material;Agent-based model from Estimating data-driven coronavirus disease 2019 mitigation strategies for safe university reopening
Creators: name: Yang, Qihui
name: Gruenbacher, Don M.
name: Scoglio, Caterina M.
Publisher: name: The Royal Society
Year: 2022
Subjects: Computational Biology

description: Additional information for survey data and simulation results ;Agent-based model developed to simulate COVID spreading in university settings
title: Το ζήτημα της αναδιοργάνωσης των αγροτικών συνεταιρισμών στις νέες κοινωνικές και τεχνολογικές συνθήκες
Creators: name: Μαραθάκη Κατερίνα
Publisher: name: Technical University of Crete
Year: 2010

description: φ. 1: Οι συνεταιρισμοί γενικά -- Κεφ. 2: Οι συνεταιρισμοί στην Ελλάδα -- Κεφ. 3: Η σημασία και ο ρόλος των αγροτικών συνεταιρισμών -- Κεφ. 4: Το νομικό πλαίσιο των αγροτικών συνεταιρισμών -- Κεφ. 5: Οι αγροτικοί συνεταιρισμοί τον 21ο αιώνα -- Κεφ. 6: Οι όροι και οι προϋποθέσεις μιας νέας αναδιοργάνωσης των Αγροτικών Συνεταιριστικών Οργανώσεων: νέα πρόταση
EIHLARDAGI TADBIRKORLIK SUBYEKTLARINING SAMARALI FAOLIYATIGA TA'SIR ETUVCHI OMILLAR
Creators: name: Nazarov, N.
Publisher: name: Zenodo
Year: 2025

description: Mazkur tezisda O‘zbekiston Respublikasida faoliyat yuritayotgan erkin iqtisodiy hududlar (EIH) doirasidagi tadbirkorlik subyektlarining samarali ishlashiga ta’sir qiluvchi asosiy ichki va tashqi omillar chuqur tahlil qilinadi. Davlat tomonidan yaratilgan qulay huquqiy va institutsional muhit, soliq va bojxona imtiyozlari, zamonaviy infratuzilmaga ega bo‘lgan maxsus zonalarning tashkil etilishi, xorijiy investitsiyalarni jalb qilishga doir choralar, shuningdek, kadrlar salohiyati va marketing strategiyalari – bularning barchasi ushbu subyektlarning samaradorligiga bevosita ta’sir ko‘rsatmoqda. Tahlillar asosida EIHlarda tadbirkorlikni rivojlantirishda mavjud muammolar va ularni bartaraf etish bo‘yicha tavsiyalar ham beriladi.
Multichannel decay: alternative derivation of the $i$-th channel decay probability
Creators: name: Giacosa, Francesco
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In the study of decays, it is quite common that an unstable quantum state/particle has multiple distinct decay channels. In this case, besides the survival probability $p(t)$, also the probability $w_{i}(t)$ that the decay occurs between $(0,t)$ in the $i$-th channel is a relevant object. The general form of the function $w_{i}(t)$ was recently presented in PLB \textbf{831} (2022), 137200. Here, we provide a novel and detailed `joint' derivation of both $p(t)$ and $w_{i}(t)$. As it is well known, $p(t)$ is not an exponential function; similarly, $w_{i}(t)$ is also not such. In particular, the ratio $w_{i}/w_{j}$ (for $i\neq j)$ is not a simple constant, as it would be in the exponential limit. The functions $w_{i}(t)$ and their mutual ratios may therefore represent a novel tool to study the non-exponential nature of the decay law.
description: 8 pages. Prepared as a proceedings contribution for the 4th Jagiellonian Symposium on Advances in Particle Physics and Medicine, Jagiellonian University, 10-15/7/2022, Krak\'ow, Poland
title: Ανασυγκρότηση κεντρικών πράσινων χώρων στην πόλη των Χανίων,
ενοποίηση του πάρκου Ειρήνης & Φιλίας και του Δημοτικού Κήπου Χανίων

title: Integration of the existing green spaces in the city of Chania,
consolidation of park “Eirinis & Filias” and the Public Garden of Chania

Creators: name: Γεωργακακη Γαβριελα
Publisher: name: Technical University of Crete
Year: 2014

description: Η παρούσα διπλωματική αφορά τον ανασχεδιασμό του αστικού υπαίθριου χώρου στην ευρύτερη περιοχή του δημοτικού κήπου, της πόλης των Χανίων, με σκοπό τη δημιουργία μιας ενιαίας τοπιακής διαμόρφωσης ενοποιόντας τον με το πάρκο Ειρήνης & Φιλίας.
  Η περιοχή αυτή συμπεριλαμβάνεται σε μία ευρύτερη ζώνη, που θα μπορούσε να δημιουργεί μία διαδρομή από το κέντρο της πόλης προς το ανατολικό προμαχώνα, ενώνοντας  διαφορετικά τμήματα της νέας και της παλιάς πόλης, με ποικιλία ως προς τη χρήση τους και το είδος της διαμόρφωσή τους. Πιο συγκεκριμένα αυτή τη ζώνη θα μπορούσαμε να τη διακρίνουμε σε πέντε τμήματα, με αρχικό την περιοχή μελέτης, έπειτα την περιοχή του σταδίου και τα τα τρία τμήματα του ανατολικού ενετικού τείχους, που χωρίζονται μεταξύ τους από το οδικό δίκτυο. Όλες αυτές οι περιοχές θα μπορούσαν να αναδειχθούν μέσα από τοπιακές διαμορφώσεις αλλά και δημόσιες λειτουργίες (π.χ. βιβλιοθήκη, μουσείο).
  Η παρούσα διπλωματική εργασία επικεντρώνεται στην περιοχή του δημοτικού κήπου και του πάρκου Ειρήνης & Φιλίας, ως την κύρια και πιο σημαντική. Η περιοχή μελέτης βρίσκεται συγκεκριμένα ανάμεσα στις κεντρικές οδούς Α. Παπανδρέου και Στρ. Τζανακάκη. Αποτελείται από ένα σύνολο διαφορετικών υπαίθριων αλλά και άλλων λειτουργιών σε ένα κεντρικό τμήμα της πόλης των Χανίων. Το πνευματικό κέντρο, το πολεμικό μουσείο (πρώην ιταλικός στρατώνας), το πάρκο Ειρήνης & Φιλίας, ο δημοτικός κήπος καθώς και το ρολόι είναι τα πέντε πιο βασικά τμήματα, χωρίς όμως αυτά να έχουν κάποια σύνδεση μεταξύ τους στην υπάρχουσα κατάσταση. Στόχος είναι ένας σχεδιασμός που θα ενοποιήσει αυτά τα διαφορετικά τμήματα με σκοπό την άμεση πρόσβαση σε αυτά αλλά και τη σύνδεσή τους με ολόκληρη την πόλη. Σκοπός είναι να υπάρχει μία καθαρή πορεία, που να διασχίζει το πάρκο αλλά παράλληλα να δίνει πρόσβαση στον δημοτικό κήπο, στο πνευματικό κέντρο και στο πολεμικό μουσείο. Για να ενισχυθεί η ζωή και η χρήση του πάρκου προτείνεται η μεταφορά του υπάρχοντος θερινού κινηματογράφου (στον δημοτικό κήπο) σε κεντρικό σημείο στη νέα διαμόρφωση του πάρκου Ειρήνης & Φιλίας καθώς και η επέκταση του ιταλικού στρατώνα με τη χρήση δημόσιας βιβλιοθήκης.
Twisted geometry for submanifolds of $\mathbb{R}^n$
Creators: name: Fiore, Gaetano
name: Weber, Thomas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 46L87, 83C65, 14A22, 16Txx

description: This is a friendly introduction to our recent general procedure for constructing noncommutative deformations of an embedded submanifold $M$ of $\mathbb{R}^n$ determined by a set of smooth equations $f^a(x)=0$. We use the framework of Drinfel'd twist deformation of differential geometry pioneered in [Aschieri et al., Class. Quantum Gravity 23 (2006), 1883]; the commutative pointwise product is replaced by a (generally noncommutative) $\star$-product induced by a Drinfel'd twist.
description: 20 pages. Submitted to PoS, as a contribution to the Proceedings of Corfu Summer Institute 2021 "School and Workshops on Elementary Particle Physics and Gravity", more precisely to the "Workshop on Quantum Geometry, Field Theory and Gravity", 20-27 September 2021
title: Memorigami - Όψεις που ανταποκρίνονται στο περιβάλλον
title: Memorigami - Climate-responsive envelopes
Creators: name: Καμπιτακη Αντιγονη-Μαρια
name: Χαμηλοθωρη Κυνθια
Publisher: name: Technical University of Crete
Year: 2014

description: Η ερευνητική αυτή εργασία έχει ως σκοπό της τη διερεύνηση, την εφαρμογή και την ανάδειξη των δυνατοτήτων τις οποίες μπορεί να προσφέρει η μεταβαλλόμενη αρχιτεκτονική, επιχειρώντας να προτείνει εναλλακτικές λύσεις στα σύγχρονα ζητήματα που αφορούν την εξοικονόμηση ενέργειας και τη βιώσιμη ανάπτυξη. Η συσχέτιση της σημασίας της όψης στην αρχιτεκτονική και στην απόδοση του κτιρίου με τους παράγοντες που συμβάλλουν στην ομαλή λειτουργία του αλλά και οι εφαρμογές νέων τεχνολογιών αποτέλεσαν τους αρχικούς προβληματισμούς για αυτή την έρευνα. Εστιάζοντας στη σημασία που έχει η όψη στην αρχιτεκτονική και ειδικότερα στην ενεργειακή απόδοση ενός κτιρίου, πρόκειται να μελετηθούν εκδοχές μεταβλητών όψεων που στόχο έχουν να δημιουργήσουν ένα δυναμικό πεδίο, τόσο για το χρήστη όσο και για το περιβάλλον. Παράλληλα, παρουσιάζεται η πορεία της έρευνάς μας για την ανάπτυξη του Memorigami, ενός πρωτότυπου ανταποκριτικού συστήματος σκίασης που ενσωματώνει κράμα μνήμης σχήματος, με στόχο την μείωση κατανάλωσης ηλεκτρικής ενέργειας.
Insights on the variability of Cu filament formation in the SiO2 electrolyte of quantized-conductance conductive bridge random access memory devices
Creators: name: Maudet, Florian
name: Deshpande, Veeresh
name: Dubourdieu, Catherine
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Conductive bridge random access memory devices such as Cu/SiO2/W are promising candidates for applications in neuromorphic computing due to their fast, low-voltage switching, multiple-conductance states, scalability, low off-current, and full compatibility with advanced Si CMOS technologies. The conductance states, which can be quantized, originate from the formation of a Cu filament in the SiO2 electrolyte due to cation-migration-based electrochemical processes. A major challenge related to the filamentary nature is the strong variability of the voltage required to switch the device to its conducting state. Here, based on a statistical analysis of more than hundred fifty Cu/SiO2/W devices, we point to the key role of the activation energy distribution for copper ion diffusion in the amorphous SiO2. The cycle-to-cycle variability is modeled well when considering the theoretical energy landscape for Cu diffusion paths to grow the filament. Perspectives of this work point to developing strategies to narrow the distribution of activation energies in amorphous SiO2.
NBC News/Wall Street Journal Poll: Clinton/Social Security/Guns
Creators: name: NBC News
name: Wall Street Journal
Publisher: name: Roper Center for Public Opinion Research
Year: 2021

description: Direction of the country (1); President Bill Clinton job performance (3); political groups and leaders job performance (7); Congressional job performance (1); Congressional elections (4); Clinton/Lewinsky situation (6); Paula Jones sexual harassment suit (1); Hillary Clinton (1); tobacco (10); sexual harassment (14); minimum wage (1); stock market (1)l economy (8); Northern Ireland Protestants vs. Catholics (2); lending money to foreign companies (3); trade (5); Social Security (4); volunteerism (2); crime (1); gun control (2); juvenile crime (3); religion brought up in (1); self described Fundamentalist/Evangelical (1).
Jeremy Steig, Adrian Guillory
Creators: name: (:Unav)
Publisher: name: Columbia University
Year: 2019

description: Ride and Roll" by Sonny Terry and Brownie McGhee, unknown blues, "What Did I Do but Be so Black and Blue" by Jackie Washington, "You're a Lucky Fellow Mr. Smith" by Sinatra interrupted by comedy sketch about marijuana, "Stars and Stripes Forever" interrupted by another comedy sketch, "Go Die Big City" by Lee Hazlewood, instrumental guitar
3D hydrodynamical survey of the impact of a companion on the morphology and dynamics of AGB outflow
Creators: name: Malfait, Jolien
name: Maes, Silke
name: Homan, Ward
name: Bolte, Jan
name: Siess, Lionel
name: De Ceuster, Frederik
name: Decin, Leen
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: With the use of high-resolution ALMA observations, complex structures that resemble those observed in post-AGB stars and planetary nebulae are detected in the circumstellar envelopes of low-mass evolved stars. These deviations from spherical symmetry are believed to be caused primarily by the interaction with a companion star or planet. With the use of three-dimensional hydrodynamic simulations, we study the impact of a binary companion on the wind morphology and dynamics of an AGB outflow. We classifiy the wind structures and morphology that form in these simulations with the use of a classification parameter, constructed with characteristic parameters of the binary configuration. Finally we conclude that the companion alters the wind expansion velocity through the slingshot mechanism, if it is massive enough.
description: Proceedings IAU Symposium No. 366, 2021, The origin of outflows in evolved stars
title: Εναέριος
Creators: name: Χασιωτης Νικολαος
Publisher: name: Technical University of Crete
Year: 2014

description: O «Εναέριος» είναι γνωστό τοπωνύμιο στο ανατολικό παραλιακό μέτωπο της Λεμεσού. Σήμερα χρησιμοποιείται ως χώρος στάθμευσης ενώ στο παρελθόν διετέλεσε τον τερματικό σταθμό μια μεγάλης εναέριας μεταλλικής κατασκευής, που κατασκευάστηκε από Ιταλούς μηχανικούς το 1923 και ξεκινούσε από το βουνό καταλήγοντας στην θάλασσα, μεταφέροντας βαγόνια με αμίαντο.

Στόχος της μελέτης είναι η κατασκευή μια σύγχρονης  ́ ́εναέριας ́ ́ μεταλλικής κατασκευής πολλαπλών χρήσεων, (καφετέριες, αίθουσες συνεδρίασης,βιβλιοθήκη κ.α) που θα καλύψει σημερινές ανάγκες της Λεμεσού, δίνοντας ένα νέο κτίριο τοπόσημο στο το παραλιακό μέτωπο.

Η Μεταλλική κατασκευή έχει σαν βασικό στοιχείο την σύγχρονη τεχνολογία, την μεταβλητότητα και τα ενεργειακά συστήματα, δίνοντας ένα μοντέρνο πρόσωπο στην συγκεκριμένη περιοχή.
Bringing work into the classroom – ill-structured problems and transfer of learning through computer simulations
Creators: name: Tan, Cheng Hock Alfred
name: Della, Christian
name: Tan, Egk Chwen, Eugene
name: Jasin, Jamil
name: Lim, Li Hong Idris
name: Wang, Pengcheng
name: Ong, Chee Ming
name: Molina-Cristobal, Arturo
Publisher: name: Singapore Institute of Technology
Year: 2024

description: Although simulation learning is a powerful, versatile and sustainable tool in the engineering classroom, its implementation can face a tough reception. This article looks at the experiences of students from the Singapore Institute of Technology - University of Glasgow (SIT-UofG), who have used simulations to tackle realistic problems and transfer learning between modules.This article is based on a paper presented at the World Engineers Summit (WES) 2023, held in Singapore, from 8 to 10 November 2023. WES 2023 was organized by the Institution of Engineers, Singapore (IES).
The effect of local magnetic moments on spectral properties and resistivity near the interaction- and doping induced Mott transitions
Creators: name: Mazitov, T. B.
name: Katanin, A. A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the effect of the formation and screening of local magnetic moments on the temperature- and interaction dependencies of spectral functions and resistivity in the vicinity of the metal-insulator transition. We use the dynamical mean-field theory for the strongly correlated Hubbard model and associate the peculiarities of the above mentioned properties with those found for the local charge $χ_c$ and spin $χ_s$ susceptibilities. We show that at half filling the maximum of resistivity at a certain temperature $T^*$ corresponds to the appearance of central quasiparticle peak of the spectral function and entering the metallic regime with well defined fermionic quasiparticles. At the same time, the temperature of the crossover to the regime with screening of local magnetic moments, determined by the minimum of double occupation, is smaller than the temperature scale $T^*$ and coincides at half filling with the boundary $T_{β=1}(U)$ corresponding to the exponent of resistivity $β\equiv d\ln ρ/d\ln T=1$. Away from half filling we find weak increase of the temperature of the beginning and completion of the screening (i.e. Kondo temperature) of local magnetic moments, while the unscreened local magnetic moments exist only up to few percents of doping. In the low temperature regime $T
description: 10 pages, 12 figures
The cumulant Green's functions method for the Hubbard model
Creators: name: Lira, Renan
name: Riseborough, Peter
name: Silva-Valencia, Jereson
name: Figueira, Marcos
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the single-band Hubbard model under the action of an external magnetic field using the cumulant Green's functions method (CGFM). The starting point of the method is to diagonalize a cluster containing N correlated sites (seed) and employ the cumulants calculated from the cluster solution to obtain the full Green's functions for the lattice. All calculations are done directly, and no self-consistent process is needed. We benchmark the one-dimensional results for the gap, the ground-state energy, and the double occupancy obtained from the CGFM against the corresponding exact results of the thermodynamic Bethe ansatz and the quantum transfer matrix methods. The results for the CGFM tend systematically to the exact one as the cluster size increases. The particle-hole symmetry of the density of states is fulfilled. The method can be applied to any parameter space for one, two, or three-dimensional Hubbard Hamiltonians and can also be extended to other strongly correlated models, like the Anderson Hamiltonian, the t-J, Kondo, and Coqblin-Schrieffer models. We also calculate the effects of positive magnetic fields as a function of the chemical potential, and we identify a finite cluster effect (Phase VI) characterized by a partially filled band and negative magnetization (n_up < n_down). This phase survives for clusters containing up to N=8 sites but tends to disappear as the size of the cluster increases. We include a simple application to spintronics, where we used these clusters as correlated quantum dots to realize a single-electron transistor when connected to Hubbard leads. We calculate the phase diagram, including the new cluster phase, using the magnetic field and chemical potential as parameters for N=7 and N=8.
description: 14 pages, 15 figures - corrected version - Results updated - New phase diagram for N=8 (figure 13b) - New section VII included
Superconductivity from orbital nematic fluctuations
Creators: name: Yamase, Hiroyuki
name: Zeyher, Roland
Publisher: name: arXiv
Year: 2013
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Recent experiments suggest that besides of antiferromagnetic fluctuations nematic fluctuations may contribute to the occurrence of superconductivity in iron pnictides. Motivated by this observation we study superconductivity from nematic fluctuations in a minimal two-band model. The employed band parameters are appropriate for iron pnictides and lead to four pockets for the Fermi line. It is shown that low-energy, long-wavelength nematic fluctuations within the pockets give rise to strong-coupling superconductivity whereas the large momenta density fluctuations between pockets are rather irrelevant. The obtained transition temperatures are similar to those typically found in the pnictides and are rather robust against repulsive Coulomb interactions. The superconducting and nematic states coexist in a large region of the phase diagram.
description: 5 pages, 4 figures
The infimum of the volumes of convex polytopes of any given facet areas is 0
Creators: name: Abrosimov, N. V.
name: Makai,, E.
name: Mednykh, A. D.
name: Nikonorov, Yu. G.
name: Rote, G.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Differential Geometry (math.DG)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 52B11, 52A38, 52A55

description: We prove the theorem mentioned in the title, for ${\mathbb{R}}^n$, where $n \ge 3$. The case of the simplex was known previously. Also, the case $n=2$ was settled, but there the infimum was some well-defined function of the side lengths. We also consider the cases of spherical and hyperbolic $n$-spaces. There we give some necessary conditions for the existence of a convex polytope with given facet areas, and some partial results about sufficient conditions for the existence of (convex) tetrahedra.
description: 42 pages, small corrections and additions, the final version
Geodesic motion and phase-space evolution of massive neutrinos
Creators: name: Elbers, Willem
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The non-trivial phase-space distribution of relic neutrinos is responsible for the erasure of primordial density perturbations on small scales, which is one of the main cosmological signatures of neutrino mass. In this paper, we present a new code, FastDF, for generating 1%-accurate particle realisations of the neutrino phase-space distribution using relativistic perturbation theory. We use the geodesic equation to derive equations of motion for massive particles moving in a weakly perturbed spacetime and integrate particles accordingly. We demonstrate how to combine geodesic-based initial conditions with the $δf$ method to minimise shot noise and clarify the definition of the neutrino momentum, finding that large errors result if the wrong parametrisation is used. Compared to standard Lagrangian methods with ad-hoc thermal motions, FastDF achieves substantial improvements in accuracy. We outline the approximation schemes used to speed up the code and to ensure symplectic integration that preserves phase-space density. Finally, we discuss implications for neutrino particles in cosmological N-body simulations. In particular, we argue that particle methods can accurately describe the neutrino distribution from $z=10^9$, when neutrinos are linear and ultra-relativistic, down to $z=0$, when they are nonlinear and non-relativistic. FastDF can be used to set up accurate initial conditions (ICs) for N-body simulations and has been integrated into the higher-order IC code monofonIC.
description: 17 pages, 6 figures, contains link to code
Searching for a Fifth Force with Atomic and Nuclear Clocks
Creators: name: Brzeminski, Dawid
name: Chacko, Zackaria
name: Dev, Abhish
name: Flood, Ina
name: Hook, Anson
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We consider the general class of theories in which there is a new ultralight scalar field that mediates an equivalence principle violating, long-range force. In such a framework, the sun and the earth act as sources of the scalar field, leading to potentially observable location dependent effects on atomic and nuclear spectra. We determine the sensitivity of current and next-generation atomic and nuclear clocks to these effects and compare the results against the existing laboratory and astrophysical constraints on equivalence principle violating fifth forces. We show that in the future, the annual modulation in the frequencies of atomic and nuclear clocks in the laboratory caused by the eccentricity of the earth's orbit around the sun may offer the most sensitive probe of this general class of equivalence principle violating theories. Even greater sensitivity can be obtained by placing a precision clock in an eccentric orbit around the earth and searching for time variation in the frequency, as is done in anomalous redshift experiments. In particular, an anomalous redshift experiment based on current clock technology would already have a sensitivity to fifth forces that couple primarily to electrons at about the same level as the existing limits. Our study provides well-defined sensitivity targets to aim for when designing future versions of these experiments.
description: 12 pages, 9 figures
title: Identifying oil families using Malcom (SLB) software package
Creators: name: Κουκουνυα Αννα
Publisher: name: Technical University of Crete
Year: 2015

description: Petroleum system definition and analysis use compositional links between petroleum and source kerogen. Petroleum families are commonly classified using qualitative or semi-quantitative methods based on compound presence or relative abundance, while petroleum-source rock correlation links a petroleum family to a stratigraphic unit, facies and/or locality containing the source kerogen. In this study, we apply multivariate statistical analysis to explore the oil family classification in Williston Basin using the Malcom (SLB) software package.
In this study twenty oil samples, that belong to five previously defined compositional families (oil families A, B, C, D and E) obtained from the Williston Basin are analyzed. The objective is to utilize biomarkers distribution and apply classification methods using the Malcom Interactive Fluid Characterization Software to identify the oil families. Principal Component Analysis (PCA), Ascending Hierarchical Classification (AHC) and Sammon mapping were employed to explore compositional data from saturated hydrocarbon fractions and hopane biomarkers of the oil samples from Williston Basin petroleum province.
	The results indicate that an efficient classification of the oil families may be obtained when the AHC was used, with Ward’s aggregation method. In addition PCA also revealed a good classification scheme of the oil families, especially when the n-alkanes are used. Finally the Malcom (SLB) software package was found to be a useful tool in geochemical data treatment.
Jeremy Steig, Joel Freedman
Creators: name: (:Unav)
Publisher: name: Columbia University
Year: 2019

description: Instrumental music plays, "Moses, Don't You Let King Pharaoh Overtake You" plays, and "Ain't Nobody's Business If I Do" by Billie Holiday play. A man discusses an Indian adaptation of George Bernard Shaw's "My Fair Lady." Covers of "Wouldn't It Be Lovely" from "My Fair Lady" in different languages play
Fitting of supernovae without dark energy
Creators: name: Lopez-Corredoira, M.
name: Calvo-Torel, J. I.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: With data from Pantheon, we have at our disposal a sample of more than a thousand supernovae Ia covering a wide range of redshifts with good precision. Here we make fits to the corresponding Hubble--Lemaître diagram with various cosmological models, with intergalactic extinction, evolution of the luminosity of supernovae, and redshift components due to partially non-cosmological factors. The data are well fitted by the standard model to include dark energy, but there is a degeneracy of solutions with several other variables. Therefore, the Hubble--Lemaître diagram of SNe Ia cannot be used alone to infer the existence of the accelerated expansion scenario with dark energy. Within this degeneracy, models that give good fits to the data include the following alternative solutions: Einstein--de Sitter with gray extinction $a_V=1.2\times 10^{-4}$ Mpc$^{-1}$; linear Hubble--Lemaître law static Euclidean with gray extinction $a_V=0.4\times 10^{-4}$ Mpc$^{-1}$; Static Euclidean with tired light and gray extinction $a_V=2.8\times 10^{-4}$ Mpc$^{-1}$; Einstein--de Sitter with absolute magnitude evolution $α=-0.10$ mag Gyr$^{-1}$; Friedmann model with $Ω_M=0.07 - 0.29$, $Ω_Λ=0$ and partially non-cosmological tired-light redshifts/blueshift with attenuation/enhancement $|K_i|<2.2\times 10^{-4}$ Mpc$^{-1}$ (although requiring calibration of $M$ incompatible with local SNe measurements).
description: accepted to be published in Int. J. Mod. Phys. D
Empirical Centroid Fictitious Play: An Approach For Distributed Learning In Multi-Agent Games
Creators: name: Swenson, Brian
name: Kar, Soummya
name: Xavier, Joao
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optimization and Control (math.OC)
subject: Computer Science and Game Theory (cs.GT)
subject: Systems and Control (eess.SY)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The paper is concerned with distributed learning in large-scale games. The well-known fictitious play (FP) algorithm is addressed, which, despite theoretical convergence results, might be impractical to implement in large-scale settings due to intense computation and communication requirements. An adaptation of the FP algorithm, designated as the empirical centroid fictitious play (ECFP), is presented. In ECFP players respond to the centroid of all players' actions rather than track and respond to the individual actions of every player. Convergence of the ECFP algorithm in terms of average empirical frequency (a notion made precise in the paper) to a subset of the Nash equilibria is proven under the assumption that the game is a potential game with permutation invariant potential function. A more general formulation of ECFP is then given (which subsumes FP as a special case) and convergence results are given for the class of potential games. Furthermore, a distributed formulation of the ECFP algorithm is presented, in which, players endowed with a (possibly sparse) preassigned communication graph, engage in local, non-strategic information exchange to eventually agree on a common equilibrium. Convergence results are proven for the distributed ECFP algorithm.
description: Submitted to the IEEE Transactions on Signal Processing
Non-equilibrium phase transitions in coupled nonlinear optical resonators
Creators: name: Roy, Arkadev
name: Nehra, Rajveer
name: Langrock, Carsten
name: Fejer, Martin
name: Marandi, Alireza
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Phase transitions and the associated symmetry breaking are at the heart of many physical phenomena. Coupled systems with multiple interacting degrees of freedom provide a fertile ground for emergent dynamics that is otherwise inaccessible in their solitary counterparts. Here we show that coupled nonlinear optical resonators can undergo self-organization in their spectrum leading to a first-order phase transition. We experimentally demonstrate such a spectral phase transition in time-multiplexed coupled optical parametric oscillators. We switch the nature of mutual coupling from dispersive to dissipative and access distinct spectral regimes of the parametric oscillator dimer. We observe abrupt spectral discontinuity at the first-order transition point which can pave the way for the realization of novel transition-edge sensors. Furthermore, we show how non-equilibrium phase transitions can lead to enhanced sensing, where the applied perturbation is not resolvable by the underlying linear system. Our results can pave the way for sensing using nonlinear driven-dissipative systems leading to performance enhancements without sacrificing sensitivity.
Reconciling the Muon g-2 and Dark Matter Relic Density with the LHC Results in Nonuniversal Gaugino Mass Models
Creators: name: Mohanty, Subhendra
name: Rao, Soumya
name: Roy, D. P.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Relatively light electroweak superparticle masses are required to satisfy the bulk annihilation region of dark matter relic density and account for the observed excess of muon g-2, while TeV scale squark and gluino masses are required to account for the 125 GeV Higgs boson mass and the negative SUSY search results from LHC. These two sets of requirements can be reconciled in a simple nonuniversal gaugino mass model, which assumes SUSY breaking via a combination of two superfields belonging to the singlet and the 200-plet representations of the GUT group SU(5). The model can be probed via squark/gluon search with the present and future LHC data. In a more general nonuniversal gaugino mass model the squark and gluino masses can be raised to the edge of the discovery limit of LHC or beyond. This model can be probed, however, through the search for electroweak pair production of the relatively light sleptons and winos with the future LHC data.
description: 15 pages, 2 figures, 4 tables, final version to be published in JHEP
Visually-Guided Sound Source Separation with Audio-Visual Predictive Coding
Creators: name: Song, Zengjie
name: Zhang, Zhaoxiang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Sound (cs.SD)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Multimedia (cs.MM)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The framework of visually-guided sound source separation generally consists of three parts: visual feature extraction, multimodal feature fusion, and sound signal processing. An ongoing trend in this field has been to tailor involved visual feature extractor for informative visual guidance and separately devise module for feature fusion, while utilizing U-Net by default for sound analysis. However, such divide-and-conquer paradigm is parameter inefficient and, meanwhile, may obtain suboptimal performance as jointly optimizing and harmonizing various model components is challengeable. By contrast, this paper presents a novel approach, dubbed audio-visual predictive coding (AVPC), to tackle this task in a parameter efficient and more effective manner. The network of AVPC features a simple ResNet-based video analysis network for deriving semantic visual features, and a predictive coding-based sound separation network that can extract audio features, fuse multimodal information, and predict sound separation masks in the same architecture. By iteratively minimizing the prediction error between features, AVPC integrates audio and visual information recursively, leading to progressively improved performance. In addition, we develop a valid self-supervised learning strategy for AVPC via co-predicting two audio-visual representations of the same sound source. Extensive evaluations demonstrate that AVPC outperforms several baselines in separating musical instrument sounds, while reducing the model size significantly. Code is available at: https://github.com/zjsong/Audio-Visual-Predictive-Coding.
description: Accepted to IEEE Transactions on Neural Networks and Learning Systems (T-NNLS)
Lessons for instructor-student interactions in physics from the world of improvisational theater
Creators: name: West, Colin G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: A considerable share of the literature on physics education and on education more broadly focuses on the principles which should guide the design of courses and of classroom activities. In this short article I wish to place more attention on the unplanned aspects of teaching: specifically, the spontaneous interactions that occur between instructors and students in settings like office hours, recitations, and when students ask questions during lecture. Because by their nature these interactions require thinking on one's feet, and depend upon the interplay between instructor and student, they share many characteristics with improvisational theater (improv). I document three foundational principles from improv literature (active listening, "yes-and," and the "button") and describe how they relate to established principles from physics education research. I provide examples of how each principle can be used to bring solid pedagogical practices to the unstructured space of instructor-student interactions.
description: 3 pages, 3 figures
Monte Carlo Studies and Optimization for the Calibration System of the GERDA Experiment
Creators: name: Baudis, Laura
name: Ferella, Alfredo D.
name: Froborg, Francis
name: Tarka, Michal
Publisher: name: arXiv
Year: 2013
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The GERmanium Detector Array, GERDA, searches for neutrinoless double beta decay in Ge-76 using bare high-purity germanium detectors submerged in liquid argon. For the calibration of these detectors gamma emitting sources have to be lowered from their parking position on top of the cryostat over more than five meters down to the germanium crystals. With the help of Monte Carlo simulations, the relevant parameters of the calibration system were determined. It was found that three Th-228 sources with an activity of 20 kBq each at two different vertical positions will be necessary to reach sufficient statistics in all detectors in less than four hours of calibration time. These sources will contribute to the background of the experiment with a total of (1.07 +/- 0.04(stat) +0.13 -0.19(sys)) 10^{-4} cts/(keV kg yr) when shielded from below with 6 cm of tantalum in the parking position.
description: 17 pages, 21 figures
title: Design of a continuous gas lift system to initiate production in a dead well
Creators: name: Τετωρος Ιωαννης
Publisher: name: Technical University of Crete
Year: 2015

description: Artificial lift systems are among the most widely used production technologies in global oil and gas operations. Wells that cannot produce liquids to the surface under their own pressure require lift technologies to enable production. Some liquid wells need lift assistance from the beginning and almost all require it sooner or later. The majority of the producing wells worldwide currently use artificial lift.
One of the most popular artificial lift methods applied in the oil industry, in order to enhance oil recovery, is the gas lift method. Its main principal is the injection of gas in the well to reduce the average density of the fluids produced from the reservoir, hence the weight of the fluid column. As a result, the declined reservoir pressure is sufficient to lift the fluids up to the surface.
The present MSc thesis is based upon a fictitious onshore well named A-1, in the Alpha field. Due to the field’s declined pressure (3,844 psi) and the increasing water cut (20.3%), production may seize in the upcoming months.
The main task is to design a gas lift system which will not only assist production during the current operating conditions, but also in future unfavorable situations where according to the reservoir forecasting, water cut is expected to increase up to 50% and reservoir pressure will drop down to 2,850 psi. The procedure of designing an optimized gas lift system in PROSPER is thoroughly described.
The main idea behind the design process was to recomplete the well once to ensure that the project will be economically viable and, on the other hand, maximized production was achieved during all operating conditions. Minimum oil production rate was set at 2000 bopd.
A continuous gas lift system design was carried out, based on the worst case scenario. Side pocket mandrels for the unloading process were set at certain depths, according to the calculations. Then, the rest of the cases, with lower water cut levels and higher reservoir pressure, were adapted to the initial side pocket mandrel spacing plan. Results showed that in all cases, the system was capable of delivering oil rates well over the minimum requested rate. Initial tubing diameter was also varied to ensure production optimization. The lowest oil rate achieved is 3,300 stb/day and the best rate is obtained at current operating conditions and is equal to 8,593 stb/day. Stability analysis of all designs indicated stable gas lift systems for all cases. The predicted production levels showed that the existing completion plan can serve for even worse scenaria in terms of system productivity.
Gibbs measures for HC-model with a countable set of spin values on a Cayley tree
Creators: name: Khakimov, R. M.
name: Makhammadaliev, M. T.
name: Rozikov, U. A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 82B26, 60K35

description: In this paper, we study the HC-model with a countable set $\mathbb Z$ of spin values on a Cayley tree of order $k\geq 2$. This model is defined by a countable set of parameters (that is, the activity function $λ_i>0$, $i\in \mathbb Z$). A functional equation is obtained that provides the consistency condition for finite-dimensional Gibbs distributions. Analyzing this equation, the following results are obtained: - Let $Λ=\sum_iλ_i$. For $Λ=+\infty$ there are no translation-invariant Gibbs measures (TIGM) and no two-periodic Gibbs measures (TPGM); - For $Λ<+\infty$, the uniqueness of TIGM is proved; - Let $Λ_{\rm cr}(k)=\frac{k^k}{(k-1)^{k+1}}$. If $0<Λ\leqΛ_{\rm cr}$, then there is exactly one TPGM that is TIGM; - For $Λ>Λ_{\rm cr}$, there are exactly three TPGMs, one of which is TIGM.
description: 15 pages, 1 figure
Gravitational Waves from the Propagation of Long Gamma-Ray Burst jets
Creators: name: Urrutia, Gerardo
name: De Colle, Fabio
name: Moreno, Claudia
name: Zanolin, Michele
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Gamma-ray bursts (GRBs) are produced during the propagation of ultra-relativistic jets. It is challenging to study the jet close to the central source, due to the high opacity of the medium. In this paper, we present numerical simulations of relativistic jets propagating through a massive, stripped envelope star associated to long GRBs, breaking out of the star and accelerating into the circumstellar medium. We compute the gravitational wave (GW) signal resulting from the propagation of the jet through the star and the circumstellar medium. We show that key parameters of the jet propagation can be directly determined by the GW signal. The signal presents a first peak corresponding to the jet duration and a second peak which corresponds to the break-out time for an observer located close to the jet axis (which in turn depends on the stellar size), or to much larger times (corresponding to the end of the acceleration phase) for off-axis observers. We also show that the slope of the GW signal before and around the first peak tracks the jet luminosity history and the structure of the progenitor star. The amplitude of the GW signal is $h_+D \sim$ hundreds to several thousands cm. Although this signal, for extragalactic sources, is outside the range of detectability of current GW detectors, it can be detected by future instruments as BBO, DECIGO and ALIA. Our results illustrate that future detections of GW associated to GRB jets may represent a revolution in our understanding of this phenomenon.
description: 10 pages, 7 Figures; Added discussion; Accepted for publication in MNRAS
title: Συμβολή των σεισμικών και ηλεκτρικών μεθόδων στον γεωτεχνικό χαρακτηρισμό των γεωλογικών σχηματισμών έδρασης των επιταχυνσιογράφων του ΕΔΕ στο Νομό Χανίων
Creators: name: Λιαντρακη Μελανθια
Publisher: name: Technical University of Crete
Year: 2015

description: Στην εργασία αυτή παρουσιάζονται και αξιολογούνται τα αποτελέσματα της γεωφυσικής έρευνας στους σταθμούς Χανίων και Παλαιόχωρας του Εθνικού Δικτύου Επιταχυνσιογράφων χρησιμοποιώντας τις μεθόδους της ηλεκτρικής τομογραφίας, της σεισμικής τομογραφίας και της πολυκάναλης ανάλυσης επιφανειακών κυμάτων. Μετά την επεξεργασία των δεδομένων με τα προγράμματα SeisImager και EarthImager προέκυψαν οι αντίστοιχες σεισμικές και γεωηλεκτρικές τομές. Ο στόχος ήταν  να συσχετιστούν γεωτεχνικά και γεωφυσικά δεδομένα.
Οι σεισμικές και γεωηλεκτρικές τομές συνδυάστηκαν με τη χρήση σχεδιαστικού προγράμματος και απεικονίστηκαν οι κυριότεροι γεωλογικοί σχηματισμοί. Επίσης, προσδιορίστηκαν οι μηχανικές ιδιότητες όπως ο λόγος του Poisson, το μέτρο ελαστικότητας και το μέτρο διάτμησης σε σχέση με το βάθος. Στη συνέχεια υπολογίστηκαν οι παράμετροι 〖Vs〗_30 καθώς και το N_sptσύμφωνα με τον ευροκώδικα.
Τέλος, προσδιορίστηκε η κατηγορία εδάφους με βάση τον ευροκώδικα 8. Η κατηγορία εδάφους για τον σταθμό των Χανίων είναι η Β. Επίσης, οι τιμές του μέγιστου μέτρου διάτμησης κυμαίνονται από 0,2 έως 0,8 GPa και οι τιμές μέτρου ελαστικότητας 1 έως 2,5 GPa. Tα γεωφυσικά αποτελέσματα συμφωνούν με τα δεδομένα της γεώτρησης ως προς τη στρωμάτωση των γεωλογικών σχηματισμών.
Η κατηγορία εδάφους για τον σταθμό της Παλαιόχωρας είναι η Γ.  Οι τιμές του μέγιστου μέτρου διάτμησης κυμαίνονται από 0,2 έως 0,7 GPa και οι τιμές μέτρου ελαστικότητας 0,5 έως 2 GPa.