cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Fractional Driven Damped Oscillator
Creators: name: Olivar-Romero, Fernando
name: Rosas-Ortiz, Oscar
Publisher: name: arXiv
Year: 2017
Subjects: subject: Classical Physics (physics.class-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The resonances associated with a fractional damped oscillator which is driven by an oscillatory external force are studied. It is shown that such resonances can be manipulated by tuning up either the coefficient of the fractional damping or the order of the corresponding fractional derivatives.
description: 5 pages, 1 Figure. A misprint appearing in Eq. (6) of the published version is amended. Based on the work presented by F. Olivar-Romero in the Quantum Fest 2016: International Conference on Quantum Phenomena, Quantum Control and Quantum Optics, 17-21 October 2016, Mexico City, Mexico
Transient Charge and Energy Balance in Graphene Induced by Ultrafast Photoexcitation
Creators: name: Zhang, Junhua
name: Schmalian, Joerg
name: Li, Tianqi
name: Wang, Jigang
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Ultrafast optical pump-probe spectroscopy measurement on monolayer graphene observes significant optical nonlinearities. We show that strongly photoexcited graphene monolayers with 35 fs pulses quasi-instantaneously build up a broadband, inverted Dirac fermion population. Optical gain emerges and directly manifests itself via a negative conductivity at the near-infrared region for the first 200fs, where stimulated emission completely compensates absorption loss in the graphene layer. To quantitatively investigate this transient, extremely dense photoexcited Dirac-fermion state, we construct a two-chemical-potential model, in addition to a time-dependent transient carrier temperature above lattice temperature, to describe the population inverted electronic state metastable on the time scale of tens of femtoseconds generated by a strong exciting pulse. The calculated transient optical conductivity reveals a complete bleaching of absorption, which sets the saturation density during the pulse propagation. Particularly, the model calculation reproduces the negative optical conductivity at lower frequencies in the states close to saturation, corroborating the observed femtosecond stimulated emission and optical gain in the wide near-infrared window.
description: 28 pages, 16 figures. Special section on ultrafast and nonlinear optics in carbon nanomaterials
Four-manifolds up to connected sum with complex projective planes
Creators: name: Kasprowski, Daniel
name: Powell, Mark
name: Teichner, Peter
Publisher: name: arXiv
Year: 2018
Subjects: subject: Geometric Topology (math.GT)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 57N13, 57N65

description: We show that closed, connected 4-manifolds up to connected sum with copies of the complex projective plane are classified in terms of the fundamental group, the orientation character and an extension class involving the second homotopy group. For fundamental groups that are torsion free or have one end, we reduce this further to a classification in terms of the homotopy 2-type.
description: 37 pages. v2: former sections 5 and 6 rewritten and split into current sections 5, 6, and 7. Accepted for publication in American Journal of Mathematics
Precession and Lense-Thirring effect of hairy Kerr spacetimes
Creators: name: Wu, Meng-He
name: Guo, Hong
name: Kuang, Xiao-Mei
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We investigate the frame-dragging effect of the hairy Kerr spacetimes on the spin of a test gyro and accretion disk. Firstly, we analyze Lense-Thirring (LT) precession frequency, geodetic precession frequency, and the general spin precession frequency of a test gyro attached to a stationary observer in the spacetime. We find that the black hole hair suppresses those precession frequencies in comparison with that occurs in Kerr spacetime in general relativity. Moreover, using those frequencies as probe, we differentiate the hairy Kerr black hole (BH) from naked singularity (NS). Specifically, as the observer approaches the central source along any direction, the frequencies grow sharply for the hairy Kerr BH, while for the hairy NS they are finite except at the ring singularity. Then, we investigate the quasiperiodic oscillations (QPOs) phenomena as the accretion disk approaches the hairy Kerr BH or NS. To this end, we analyze the bound circular orbits and their perturbations. We find that as the orbits approach the corresponding inner-most stable circular orbit (ISCO), both LT precession frequency and periastron precession frequency behave differently in the hairy Kerr BH and NS. Additionally, the hairy parameters have significant effects on the two frequencies. We expect that our theoretical studies could shed light on astrophysical observations in distinguishing hairy theories from Einstein's gravity, and also in distinguishing BH from NS in spacetime with hair.
description: 18 pages,12 figures, published on 17 March 2023
An Evolutionary Algorithm Approach to Link Prediction in Dynamic Social Networks
Creators: name: Bliss, Catherine A.
name: Frank, Morgan R.
name: Danforth, Christopher M.
name: Dodds, Peter Sheridan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Social and Information Networks (cs.SI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Many real world, complex phenomena have underlying structures of evolving networks where nodes and links are added and removed over time. A central scientific challenge is the description and explanation of network dynamics, with a key test being the prediction of short and long term changes. For the problem of short-term link prediction, existing methods attempt to determine neighborhood metrics that correlate with the appearance of a link in the next observation period. Recent work has suggested that the incorporation of topological features and node attributes can improve link prediction. We provide an approach to predicting future links by applying the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) to optimize weights which are used in a linear combination of sixteen neighborhood and node similarity indices. We examine a large dynamic social network with over $10^6$ nodes (Twitter reciprocal reply networks), both as a test of our general method and as a problem of scientific interest in itself. Our method exhibits fast convergence and high levels of precision for the top twenty predicted links. Based on our findings, we suggest possible factors which may be driving the evolution of Twitter reciprocal reply networks.
description: 17 pages, 12 figures, 4 tables, Submitted to the Journal of Computational Science
Explaining the winds of AGB stars: Recent progress
Creators: name: Höfner, Susanne
name: Freytag, Bernd
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The winds observed around asymptotic giant branch (AGB) stars are generally attributed to radiation pressure on dust, which is formed in the extended dynamical atmospheres of these pulsating, strongly convective stars. Current radiation-hydrodynamical models can explain many of the observed features, and they are on the brink of delivering a predictive theory of mass loss. This review summarizes recent results and ongoing work on winds of AGB stars, discussing critical ingredients of the driving mechanism, and first results of global 3D RHD star-and-wind-in-a-box simulations. With such models it becomes possible to follow the flow of matter, in full 3D geometry, all the way from the turbulent, pulsating interior of an AGB star, through its atmosphere and dust formation zone into the region where the wind is accelerated by radiation pressure on dust. Advanced instruments, which can resolve the stellar atmospheres, where the winds originate, provide essential data for testing the models.
description: Accepted for publication in "The Origin of Outflows in Evolved Stars", Proceedings of IAU Symposium 366 (8 pages, 2 figures)
Making the Most of Text Semantics to Improve Biomedical Vision--Language Processing
Creators: name: Boecking, Benedikt
name: Usuyama, Naoto
name: Bannur, Shruthi
name: Castro, Daniel C.
name: Schwaighofer, Anton
name: Hyland, Stephanie
name: Wetscherek, Maria
name: Naumann, Tristan
name: Nori, Aditya
name: Alvarez-Valle, Javier
name: Poon, Hoifung
name: Oktay, Ozan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: Multi-modal data abounds in biomedicine, such as radiology images and reports. Interpreting this data at scale is essential for improving clinical care and accelerating clinical research. Biomedical text with its complex semantics poses additional challenges in vision--language modelling compared to the general domain, and previous work has used insufficiently adapted models that lack domain-specific language understanding. In this paper, we show that principled textual semantic modelling can substantially improve contrastive learning in self-supervised vision--language processing. We release a language model that achieves state-of-the-art results in radiology natural language inference through its improved vocabulary and novel language pretraining objective leveraging semantics and discourse characteristics in radiology reports. Further, we propose a self-supervised joint vision--language approach with a focus on better text modelling. It establishes new state of the art results on a wide range of publicly available benchmarks, in part by leveraging our new domain-specific language model. We release a new dataset with locally-aligned phrase grounding annotations by radiologists to facilitate the study of complex semantic modelling in biomedical vision--language processing. A broad evaluation, including on this new dataset, shows that our contrastive learning approach, aided by textual-semantic modelling, outperforms prior methods in segmentation tasks, despite only using a global-alignment objective.
description: To appear in ECCV 2022. Code: https://aka.ms/biovil-code Dataset: https://aka.ms/ms-cxr Demo Notebook: https://aka.ms/biovil-demo-notebook
Comment on "Giant Plasticity of a Quantum Crystal"
Creators: name: Zhou, C.
name: Reichhardt, C.
name: Graf, M. J.
name: Su, J. -J.
name: Balatsky, A. V.
name: Beyerlein, I. J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In their Letter, Haziot et al. [Phys. Rev. Lett. 110 (2013) 035301] report a novel phenomenon of giant plasticity for hcp Helium-4 quantum crystals. They assert that Helium-4 exhibits mechanical properties not found in classical plasticity theory. Specifically, they examine high-quality crystals as a function of temperature and applied strain, where the shear modulus reaches a plateau and dissipation becomes close to zero; both quantities are reported to be independent of stress and strain, implying a reversible dissipation process and quantum tunneling. In this Comment, we show that these signatures can be explained with a classical model of thermally activated dislocation glide without the need to invoke quantum tunneling or dissipationless motion. Recently, we proposed a dislocation glide model in solid Helium-4 containing the dissipation contribution in the presence of other dislocations with qualitatively similar behavior [Zhou et al., Philos. Mag. Lett. 92 (2012) 608].
description: 1 page, 1 figure, comment; minor revisions
Stabilizing GANs' Training with Brownian Motion Controller
Creators: name: Luo, Tianjiao
name: Zhu, Ziyu
name: Chen, Jianfei
name: Zhu, Jun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Dynamical Systems (math.DS)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: The training process of generative adversarial networks (GANs) is unstable and does not converge globally. In this paper, we examine the stability of GANs from the perspective of control theory and propose a universal higher-order noise-based controller called Brownian Motion Controller (BMC). Starting with the prototypical case of Dirac-GANs, we design a BMC to retrieve precisely the same but reachable optimal equilibrium. We theoretically prove that the training process of DiracGANs-BMC is globally exponential stable and derive bounds on the rate of convergence. Then we extend our BMC to normal GANs and provide implementation instructions on GANs-BMC. Our experiments show that our GANs-BMC effectively stabilizes GANs' training under StyleGANv2-ada frameworks with a faster rate of convergence, a smaller range of oscillation, and better performance in terms of FID score.
Interplay between Riccati, Ermakov and Schroedinger equations to produce complex-valued potentials with real energy spectrum
Creators: name: Blanco-Garcia, Zurika
name: Rosas-Ortiz, Oscar
name: Zelaya, Kevin
Publisher: name: arXiv
Year: 2018
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Nonlinear Riccati and Ermakov equations are combined to pair the energy spectrum of two different quantum systems via the Darboux method. One of the systems is assumed Hermitian, exactly solvable, with discrete energies in its spectrum. The other system is characterized by a complex-valued potential that inherits all the energies of the former one, and includes an additional real eigenvalue in its discrete spectrum. If such eigenvalue coincides with any discrete energy (or it is located between two discrete energies) of the initial system, its presence produces no singularities in the complex-valued potential. Non-Hermitian systems with spectrum that includes all the energies of either Morse or trigonometric Poeschl-Teller potentials are introduced as concrete examples.
description: 21 pages, 12 figures
Calibration of the Tully-Fisher relation in the WISE W1 ($3.4μ\rm m$) and W2 ($4.6μ\rm m$) Bands
Creators: name: Bell, Rianna
name: Said, Khaled
name: Davis, Tamara
name: Jarrett, T. H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In this paper, we present our calibrations of the TF relation in the mid-infrared W1 ($3.4μ$m) and W2 ($4.6μ$m) bands, using large samples 848 galaxies and 857 galaxies in the W1 and W2 bands respectively. In this calibration we performed a correction for the cluster population incompleteness bias, and a morphological type correction. The calibration was performed using a new, iterative bivariate fitting procedure. For these calibrations we used the total absolute magnitudes, and HI linewidths $W_{F50}$ derived from the HI global profiles as a measure of the rotational velocities. We then performed two additional calibrations on the same sample using (i) the isophotal magnitudes and (ii) the average rotational velocities measured along the flat sections of the spatially resolved rotation curves of the galaxies, which were obtained from the empirical conversion between rotational velocity definitions. We compared these three calibrations to determine whether the use of isophotal magnitudes, or spatially resolved rotational velocities have a significant impact on the scatter around the TF relations in the W1 and W2 bands. We found that the original calibrations using total magnitudes and \hi linewidths had the smallest total scatters. These calibrations are given by $M_{\rm Tot, W1} = (2.02 \pm 0.44) - (10.08 \pm 0.17)\log_{10}(W_{F50})$ and $M_{\rm Tot, W2} = (2.00 \pm 0.44) - (10.11 \pm 0.17)\log_{10}(W_{F50})$, with associated total scatters of $σ_{W1} = 0.68$ and $σ_{W2} = 0.69$. Finally, we compared our calibrations in the mid-infrared bands with previous calibrations in the near-infrared J, H and K bands and the long-wavelength optical I band, which used the same two corrections. The differences between these relations can be explained by considering the different regions and components of spiral galaxies that are traced by the different wavelengths.
description: 16 pages, 17 figures, 1 table, submitted to MNRAS, comments are welcome
title: Μελέτη συμπεριφοράς κονιαμάτων από συνθετικό λαρνίτη και πορτλανδίτη με διαβαθμισμένη χαλαζιακή άμμο
Creators: name: Διακρουσης Στυλιανος-Γερασιμος
Publisher: name: Technical University of Crete
Year: 2011

description: Η παρούσα διπλωματική εργασία εκπονήθηκε στο εργαστήριο Πετρολογίας και Οικονομικής Γεωλογίας, του τμήματος Μηχανικών Ορυκτών Πόρων του Πολυτεχνείου Κρήτης.
Σκοπός της διπλωματικής εργασίας ήταν η κατασκευή υδραυλικών κονιαμάτων με μίγματα συνθετικού λαρνίτη, υδράσβεστου, και χαλαζιακής άμμου ως αδρανές για την μελέτη τους ως προς την αντοχή τους και τις ορυκτολογικές αλλαγές τους.
 Η εργασία πραγματοποιήθηκε σε τέσσερα βασικά στάδια. Στο πρώτο στάδιο πραγματοποιήθηκε η σύνθεση του λαρνίτη, η οποία προέκυψε ύστερα από ανάμειξη πορτλανδίτη με χαλαζία, με βάση τη στοιχειομετρία του λαρνίτη, σε συγκεκριμένες συνθήκες θερμοκρασίας και χρόνου έψησης. Στο δεύτερο στάδιο δημιουργήθηκαν τρία διαφορετικά μείγματα υδραυλικών κονιών με βάση την περιεκτικότητά της σε λαρνίτη και πορτλανδίτη. Στο τρίτο στάδιο κατασκευάστηκαν δοκίμια από τα παραπάνω τρία είδη κονιών, τα οποία χαρακτηρίζονται από συγκεκριμένες αναλογίες κονίας, αδρανών υλικών (χαλαζιακή διαβαθμισμένη άμμο) και νερού. Έπειτα τα δοκίμια αυτά υποβλήθηκαν σε δοκιμές μονοαξονικής θλίψης και εφελκυσμού τύπου Brazil, σε 7, 28, 60 και 90 ημέρες. Στο τέταρτο στάδιο πραγματοποιήθηκε ορυκτολογική ανάλυση των δειγμάτων τα οποία είχαν ληφθεί αμέσως μετά τις δοκιμές. Η ορυκτολογική ανάλυση έγινε με τη μέθοδο της περιθλασιμετρίας ακτίνων -Χ.
Συνδυάζοντας τις  μηχανικές αντοχές  με τις  αντίστοιχες ορυκτολογικές αναλύσεις  των δοκιμίων, αποδεικνύεται  ότι η θλιπτική  αντοχή εξαρτάται από το  ποσοστό του  λαρνίτη στο  δοκίμιο.  Επιπλέον,  διαπιστώθηκε   γραμμική σχέση, και για τα τρία κονιάματα, μεταξύ του ποσοστού του λαρνίτη και του    χρόνου ωρίμανσης
Pump-Controlled Directional Light Emission from Random Lasers
Creators: name: Hisch, Thomas
name: Liertzer, Matthias
name: Pogany, Dionyz
name: Mintert, Florian
name: Rotter, Stefan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The angular emission pattern of a random laser is typically very irregular and difficult to tune. Here we show by detailed numerical calculations that one can overcome the lack of control over this emission pattern by actively shaping the spatial pump distribution. We demonstrate, in particular, how to obtain customized pump profiles to achieve highly directional emission. Going beyond the regime of strongly scattering media where localized modes with a given directionality can simply be selected by the pump, we present an optimization-based approach which shapes extended lasing modes in the weakly scattering regime according to any predetermined emission pattern.
description: 5 pages, 4 figures plus 5 pages supplemental material
Teaching SLIFE in Public Schools
Creators: name: Morgenegg, Katherine
Publisher: name: Columbia University
Year: 2019
Subjects: Student teachers
Teacher-student relationships
Education
Immigrant students
English language--Study and teaching--Foreign speakers

description: Amiir [pseudonym] came to America from Syria via truck. I know this because when he first broke his silent phase he pointed to a photo of a truck in the room and said, “Me in truck.” Through a fraught interview process, he explained he had journeyed in the side container.
Психологические проблемы семьи больного, перенесшего инсульт
Creators: name: Котельникова А.В.
name: Кукшина А.А.
Publisher: name: Медицинская психология в России
Year: 2020
Subjects: инсульт
горевание
реабилитация
привержен-ность к лечению
саморегуляция
эмоциональное состояние
стресс.

description: В настоящей работе представлены результаты анализа литературы и клинической документации, отражающей работу психологической службы в отношении семей больных, находившихся на медицинской реабилитации после перенесенного инсульта. Цель — выявление основных мишеней психологического сопровождения родственников. Предлагается классификация психологических проблем на основании количества времени, прошедшего с момента получения известия о тяжелом заболевании родственника, и особенностями эмоционального реагирования на различных этапах реабилитационного процесса каждого из участников семейной системы. В качестве основных мишеней работы медицинского психолога с родственниками больных, перенесших инсульт, обозначены неполное понимание членами семьи особенностей личности и эмоционального состояния больного, недостаточная адаптация психоэмоционального состояния ухаживающих родственников, проблемы с эмоциональной саморегуляцией и выбором оптимальных адекватных поведенческих стратегий при взаимодействии с больным, межличностные, в том числе детско-родительские, отношения в связи с изменением внутрисемейной ситуации.
Equation-free surrogate modeling of geophysical flows at the intersection of machine learning and data assimilation
Creators: name: Pawar, Suraj
name: San, Omer
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: There is a growing interest in developing data-driven reduced-order models for atmospheric and oceanic flows that are trained on data obtained either from high-resolution simulations or satellite observations. The data-driven models are non-intrusive in nature and offer significant computational savings compared to large-scale numerical models. These low-dimensional models can be utilized to reduce the computational burden of generating forecasts and estimating model uncertainty without losing the key information needed for data assimilation to produce accurate state estimates. This paper aims at exploring an equation-free surrogate modeling approach at the intersection of machine learning and data assimilation in Earth system modeling. With this objective, we introduce an end-to-end non-intrusive reduced-order modeling (NIROM) framework equipped with contributions in modal decomposition, time series prediction, optimal sensor placement, and sequential data assimilation. Specifically, we use proper orthogonal decomposition (POD) to identify the dominant structures of the flow, and a long short-term memory network to model the dynamics of the POD modes. The NIROM is integrated within the deterministic ensemble Kalman filter (DEnKF) to incorporate sparse and noisy observations at optimal sensor locations obtained through QR pivoting. The feasibility and the benefit of the proposed framework are demonstrated for the NOAA Optimum Interpolation Sea Surface Temperature (SST) V2 dataset. Our results indicate that the NIROM is stable for long-term forecasting and can model dynamics of SST with a reasonable level of accuracy. Furthermore, the prediction accuracy of the NIROM gets improved by one order of magnitude by the DEnKF algorithm. This work provides a way forward toward transitioning these methods to fuse information from Earth system models and observations to achieve accurate forecasts.
The 4 June 2011 neutron event at Mercury: A defense of the solar origin hypothesis
Creators: name: Lawrence, David J.
name: Feldman, William C.
name: Peplowski, Patrick N.
name: Solomon, Sean C.
Publisher: name: Columbia University
Year: 2015
Subjects: Planetary science
Solar radiation

description: We address the claim that an increase in the flux of neutrons detected by the Neutron Spectrometer (NS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft in orbit about Mercury at 15:45 UTC on 4 June 2011 was generated by the impact of energetic ions onto spacecraft. We find this claim to be unwarranted. The claim is grounded on the erroneous assumption that the NS singles count rate is triggered only by energetic ions. Rather, because any mix of energetic ions, electrons, photons, and neutrons can trigger NS singles, these data do not provide a reliable constraint on the presence of energetic ions. The absence of an enhancement in the count rate of 1635‐keV gamma rays, as monitored by the MESSENGER Gamma‐Ray Spectrometer, provides independent evidence that a fluence of energetic protons sufficiently high to generate the neutron enhancement was not present during the neutron event. The interpretation that currently best matches the available data is that the neutron enhancement on 4 June 2011 was the result of solar neutrons.
title: Ανάλυση κρατήσεων πάγιου εξοπλισμού στο ορυχείο Μαυροπηγής, του Λιγνιτικού Κέντρου Δυτικής Μκαεδονίας.
Creators: name: Σπανος Κωνσταντινος
Publisher: name: Technical University of Crete
Year: 2015

description: Η εκμετάλλευση των λιγνιτικών κοιτασμάτων είναι στρατηγικής σημασίας για την παραγωγή ενέργειας στην Ελλάδα. Η χώρα μας κατέχει τη δεύτερη θέση σε παραγωγή λιγνίτη στην Ευρωπαϊκή Ένωση και την έκτη παγκοσμίως. Βασικός πυλώνας για την ομαλή και συνεχή λειτουργία της παραγωγική διαδικασίας αποτελεί ο πάγιος εξοπλισμός των ορυχείων.
Στόχος της παρούσας διπλωματικής εργασίας είναι η λεπτομερής παρουσίαση και η στατιστική ανάλυση των κρατήσεων του πάγιου εξοπλισμού του Ορυχείου Κυρίου Πεδίου για το έτος 2013. Τα δεδομένα που χρησιμοποιήθηκαν προέρχονται από την εξελιγμένη Εφαρμογή Καταγραφής των Κρατήσεων (PET) η οποία ξεκίνησε να λειτουργεί στο ορυχείο από το 2012. Η ανάλυση των στοιχείων που αντλήθηκαν από την ως άνω εφαρμογή πραγματοποιήθηκαν σε περιβάλλον Excel.
Στην ανάλυση περιλαμβάνεται σύγκριση των δεδομένων των κρατήσεων για κάθε Ομάδα κράτησης και για κάθε στοιχείο του εξοπλισμού ξεχωριστά. Τα αποτελέσματα παρουσιάζουν αναλυτικά τις κυριότερες αιτίες κράτησης του εξοπλισμού, ενώ προκύπτει ανάγκη περαιτέρω κατηγοριοποίησης των κρατήσεων.
A Hybrid Josephson Transmission Line and Passive Transmission Line Routing Framework for Single Flux Quantum Logic
Creators: name: Yang, Shucheng
name: Gao, Xiaoping
name: Yang, Ruoting
name: Ren, Jie
name: Wang, Zhen
Publisher: name: arXiv
Year: 2022
Subjects: subject: Emerging Technologies (cs.ET)
subject: Hardware Architecture (cs.AR)
subject: FOS: Computer and information sciences

description: The Single Flux Quantum (SFQ) logic family is a novel digital logic as it provides ultra-fast and energy-efficient circuits. For large-scale SFQ circuit design, specialized electronic design automation (EDA) tools are required due to the differences in logic type, timing constraints and circuit architecture, in contrast to the CMOS logic. In order to improve the overall performance of an SFQ circuit, an efficient routing algorithm should be applied during the layout design to perform accurate timing adjustment for fixing hold violations and optimizing critical paths. Thus, a hybrid Josephson transmission line and passive transmission line routing framework is proposed. It consists of four main modules and an exploration of the potential timing performance based on the given layout placement. The proposed routing tool is demonstrated on seven testbench circuits. The obtained results demonstrate that the operating frequency is greatly improved, and all the hold violations are eliminated for each circuit.
Problems with Propagation and Time Evolution in f(T) Gravity
Creators: name: Ong, Yen Chin
name: Izumi, Keisuke
name: Nester, James M.
name: Chen, Pisin
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Teleparallel theories of gravity have a long history. They include a special case referred to as the Teleparallel Equivalent of General Relativity (TEGR, aka GR$_{\|}$). Recently this theory has been generalized to f(T) gravity. Tight constraints from observations suggest that f(T) gravity is not as robust as initially hoped. This might hint at hitherto undiscovered problems at the theoretical level. In this work, we point out that a generic f(T) theory can be expected to have certain problems including superluminal propagating modes, the presence of which can be revealed by using the characteristic equations that govern the dynamics in f(T) gravity and/or the Hamiltonian structure of the theory via Dirac constraint analysis. We use several examples from simpler gauge field theories to explain how such superluminal modes could arise. We also point out problems with the Cauchy development of a constant time hypersurface in FLRW spacetime in f(T) gravity. The time evolution from a FLRW (and as a special case, Minkowski spacetime) initial condition is not unique.
description: Version accepted by PRD
title: Διερεύνηση των αντιμικροβιακών ιδιοτήτων σμεκτιτικών αργίλων. Επίδραση του φορτίου κρυσταλλικής δομής
Creators: name: Σισμανης Κυριαζης-Αθανασιος
Publisher: name: Technical University of Crete
Year: 2015

description: Ο στόχος της παρούσας διπλωματικής εργασίας είναι η διερεύνηση της αντιβακτηριακής δράσης των εμπλουτισμένων με άργυρο αργίλων. Η διερεύνηση πραγματοποιήθηκε πειραματικά in vitro σε δύο βακτήρια, Enterococcus faecalis και Escherichia coli. Τα αποτελέσματα της πειραματικής διαδικασίας υποδεικνύουν ότι η αντιβακτηριακή ιδιότητα των αργίλων εμπλουτισμένων με άργυρο σε ποσοστά 1% δεν είναι εμφανής και επίσης ότι δεν προκύπτει κάποια ξεκάθαρη αντιβακτηριακή ιδιότητα των σμεκτιτών.
Superpositions of bright and dark solitons supporting the creation of balanced gain and loss optical potentials
Creators: name: Rosas-Ortiz, Oscar
name: Cruz, Sara Cruz y
Publisher: name: arXiv
Year: 2018
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Bright and dark solitons of the cubic nonlinear Schrodinger equation are used to construct complex-valued potentials with all-real spectrum. The real part of these potentials is equal to the intensity of a bright soliton while their imaginary part is defined by the product of such soliton with its concomitant, a dark soliton. Considering light propagation in Kerr media, the real part of the potential refers to the self-focusing of the signal and the imaginary one provides the system with balanced gain-and-loss rates.
description: 6 figures, 17 pages, LaTeX file. The manuscript has been re-organized (abstract, introduction and conclusions rewritten), and it now includes an appendix with detailed calculations of some relevant results reported in the paper. New references were added
Comprehensive survey of energetic electron events in Mercury's magnetosphere with data from the MESSENGER Gamma‐Ray and Neutron Spectrometer
Creators: name: Lawrence, David J.
name: Anderson, Brian J.
name: Baker, Daniel N.
name: Feldman, William C.
name: Ho, George C.
name: Korth, Haje
name: McNutt Jr., Ralph L.
name: Peplowski, Patrick N.
name: Solomon, Sean C.
name: Starr, Richard D.
name: Vandegriff, Jon D.
name: Winslow, Reka M.
Publisher: name: Columbia University
Year: 2015
Subjects: Planetary science
Planets--Magnetospheres

description: Data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Gamma‐Ray and Neutron Spectrometer have been used to detect and characterize energetic electron (EE) events in Mercury's magnetosphere. This instrument detects EE events indirectly via bremsstrahlung photons that are emitted when instrument and spacecraft materials stop electrons having energies of tens to hundreds of keV. From Neutron Spectrometer data taken between 18 March 2011 and 31 December 2013 we have identified 2711 EE events. EE event amplitudes versus energy are distributed as a power law and have a dynamic range of a factor of 400. The duration of the EE events ranges from tens of seconds to nearly 20 min. EE events may be classified as bursty (large variation with time over an event) or smooth (small variation). Almost all EE events are detected inside Mercury's magnetosphere on closed field lines. The precise occurrence times of EE events are stochastic, but the events are located in well‐defined regions with clear boundaries that persist in time and form what we call “quasi‐permanent structures.” Bursty events occur closer to dawn and at higher latitudes than smooth events, which are seen near noon‐to‐dusk local times at lower latitudes. A subset of EE events shows strong periodicities that range from hundreds of seconds to tens of milliseconds. The few‐minute periodicities are consistent with the Dungey cycle timescale for the magnetosphere and the occurrence of substorm events in Mercury's magnetotail region. Shorter periods may be related to phenomena such as north‐south bounce processes for the energetic electrons.
Parametric decay and the origin of the low frequency Alfvénic spectrum of the solar wind
Creators: name: Victor, Réville
name: Anna, Tenerani
name: Marco, Velli
Publisher: name: arXiv
Year: 2018
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The fast solar wind shows a wide spectrum of transverse magnetic and velocity field perturbations. These perturbations are strongly correlated in the sense of Alfvén waves propagating mostly outward, from the Sun to the interplanetary medium. They are likely to be fundamental to the acceleration and the heating of the solar wind. However, the precise origin of the broadband spectrum is to date unknown. Typical periods of chromospheric Alfvén waves are limited to a few minutes, and any longer period perturbations should be strongly reflected at the transition region. In this work, we show that minute long Alfvénic fluctuations are unstable to the parametric instability. Parametric instability enables an inverse energy cascade by exciting several hours long periods Alfvénic fluctuations together with strong density fluctuations (typically between 1 and $20 R_{\odot}$). These results may improve our understanding of the origin of the solar wind turbulent spectrum and will be tested by the Parker Solar Probe.
description: 11 pages, 11 figures, to appear in the Astrophysical Journal
Dwork crystals I
Creators: name: Beukers, Frits
name: Vlasenko, Masha
Publisher: name: arXiv
Year: 2019
Subjects: subject: Number Theory (math.NT)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics

description: We present an elementary elaboration of Dwork's idea of explicit $p$-adic limit formulas for zeta functions of toric hypersurfaces.
description: This version is identical with the earlier one, we only change the numeration of theorems so that it agrees with the version published by IMRN
Plastic response by dislocation glide in solid helium under dc strain rate loading
Creators: name: Zhou, Caizhi
name: Su, Jung-Jung
name: Graf, Matthias J.
name: Reichhardt, Charles
name: Balatsky, Alexander V.
name: Beyerlein, Irene J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We develop a model for the gliding of dislocations and plasticity in solid He-4. This model takes into account the Peierls barrier, multiplication and interaction of dislocations, as well as classical thermally and mechanically activated processes leading to dislocation glide. We specifically examine the dc stress-strain curve and how it is affected by temperature, strain rate, and dislocation density. As a function of temperature and shear strain, we observe plastic deformation and discuss how this may be related to the experimental observation of elastic anomalies in solid hcp He-4 that have been discussed in connection with the possibility of supersolidity or giant plasticity. Our theory gives several predictions for the dc stress strain curves, for example, the yield point and the change in the work-hardening rate and plastic dissipation peak, that can be compared directly to constant strain rate experiments and thus provide bounds on model parameters.
description: 10 pages, 8 figures; minor revisions of accepted version
title: Ανάπτυξη αλγορίθμου ταυτοποίησης βιοδεικτών του πετρελαίου σε δεδομένα αέριας χρωματογραφίας - φασματοσκοπίας μάζας (GC-MS)
Creators: name: Ξυδης Αναστασιος-Αλεξανδρος
Publisher: name: Technical University of Crete
Year: 2015

description: Στόχος της παρούσας διπλωματικής εργασίας είναι η δημιουργία μιας ψηφιακής  βάσης φασμάτων μάζας βιοδεικτών πετρελαίου και η χρησιμοποίηση της στην ταυτοποίηση των ενώσεων αυτών σε πετρελαϊκά δείγματα με βάση τα πειραματικά δεδομένα αέριας χρωματογραφίας - φασματοσκοπίας μάζας (GC-MS).
	Οι βιοδείκτες είναι σύνθετες οργανικές ενώσεις, οι οποίες ανιχνεύονται στα εκχυλίσματα μητρικών πετρωμάτων, στο πετρέλαιο, στους γαιάνθρακες και γενικά σε όλα τα οργανογενή ορυκτά καύσιμα. Η αξία των βιοδεικτών έγκειται στη ομοιότητα της χημικής δομής τους με εκείνη μορίων της πρόδρομης οργανικής ύλης των ορυκτών καυσίμων. Με βάση τη συσχέτιση αυτή είναι δυνατή η συγκέντρωση σημαντικών πληροφοριών για το περιβάλλον και τις συνθήκες δημιουργίας και διατήρησης του πετρελαίου και των άλλων ορυκτών καυσίμων στους γεωλογικούς σχηματισμούς. Η πληροφορίες αυτές είναι σημαντικές στην αναζήτηση σχηματισμών ορυκτών καυσίμων, σε συνδυασμό βέβαια με τα διαθέσιμα γεωλογικά και γεωφυσικά δεδομένα.
	Η πολυπλοκότητα της δομής των βιοδεικτών αλλά και ο μεγάλος αριθμός ισομερών που εμφανίζουν, καθιστά δύσκολη την ταυτοποίηση τους ακόμη και με τις σύγχρονες μεθόδους ανάλυσης, ενώ δεν είναι διαθέσιμες εμπορικές βιβλιοθήκες φασμάτων βιοδεικτών. Στα πλαίσια της παρούσας εργασίας αναπτύχθηκε μια γρήγορη, αλλά ακριβής διαδικασία ψηφιοποίησης φασμάτων μάζας βιοδεικτών με βάση τις διαθέσιμες στη βιβλιογραφία εικόνες τους, με χρήση AutoCad και Matlab. Τα ψηφιοποιημένα φάσματα από 200+ ενώσεις εντάχθηκαν σε βιβλιοθήκη φασμάτων, η οποία μπορεί να λειτουργεί εντός των εμπορικών λογισμικών επεξεργασίας δεδομένων GC-MS (Mass Hunder, ChemStation). Επιπλέον αναπτύχθηκαν σε περιβάλλον Matlab αλγόριθμοι συσχέτισης και ταυτοποίησης ενώσεων με βάση τη βιβλιοθήκη φασμάτων, οι οποίοι λειτουργούν ανεξάρτητα από τα εμπορικά λογισμικά επεξεργασίας δεδομένων GC-MS και οι οποίοι εξασφαλίζουν ευελιξία αναφορικά με τα κριτήρια συσχέτισης.
	Η χρήσης της βιβλιοθήκης που αναπτύχθηκε (Bio_X) σε πραγματικά πειραματικά δεδομένα ανάλυσης δειγμάτων πετρελαίου έδειξε ότι με επιτυχία μπορούν να ταυτοποιηθούν οι κυριότεροι βιοδείκτες που χρησιμοποιούνται στις τυπικές γεωχημικές μελέτες. Επιπλέον η βιβλιοθήκη επιτρέπει την εύκολη συμπλήρωση της με νέα δεδομένα, καθιστώντας την έτσι σημαντική βάση για περισσότερο απαιτητικές εφαρμογές στο μέλλον.
Optimized Backhaul Compression for Uplink Cloud Radio Access Network
Creators: name: Zhou, Yuhan
name: Yu, Wei
Publisher: name: arXiv
Year: 2013
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: This paper studies the uplink of a cloud radio access network (C-RAN) where the cell sites are connected to a cloud-computing-based central processor (CP) with noiseless backhaul links with finite capacities. We employ a simple compress-and-forward scheme in which the base-stations(BSs) quantize the received signals and send the quantized signals to the CP using either distributed Wyner-Ziv coding or single-user compression. The CP decodes the quantization codewords first, then decodes the user messages as if the remote users and the cloud center form a virtual multiple-access channel (VMAC). This paper formulates the problem of optimizing the quantization noise levels for weighted sum rate maximization under a sum backhaul capacity constraint. We propose an alternating convex optimization approach to find a local optimum solution to the problem efficiently, and more importantly, establish that setting the quantization noise levels to be proportional to the background noise levels is near optimal for sum-rate maximization when the signal-to-quantization-noise ratio (SQNR) is high. In addition, with Wyner-Ziv coding, the approximate quantization noise level is shown to achieve the sum-capacity of the uplink C-RAN model to within a constant gap. With single-user compression, a similar constant-gap result is obtained under a diagonal dominant channel condition. These results lead to an efficient algorithm for allocating the backhaul capacities in C-RAN. The performance of the proposed scheme is evaluated for practical multicell and heterogeneous networks. It is shown that multicell processing with optimized quantization noise levels across the BSs can significantly improve the performance of wireless cellular networks.
description: 13 pages, 8 figures; published in IEEE Journal on Selected Areas in Communications, Special Issue on 5G Communication Systems, June 2014
title: Βιοαποδόμηση πετρελαϊκών υδρογονανθράκων στο περιβάλλον. Η επίδραση των θρεπτικών
Creators: name: Τσαχουριδης Αγγελος
Publisher: name: Technical University of Crete
Year: 2015

description: Η εξυγίανση του περιβάλλοντος σε περιπτώσεις μεγάλων διαρροών πετρελαίου αποτελεί ιδιαίτερα σύνθετο τεχνολογικά επίτευγμα. Στις περιπτώσεις αυτές, εξαιρετικά αποτελεσματική έχει αποδειχθεί η μέθοδος της ενισχυμένης βιοαποικοδόμησης του πετρελαίου η οποία στηρίζεται στην ικανότητα κάποιων μικροοργανισμών-βακτηρίων και μυκήτων- να αποδομούν το πετρέλαιο σε σχετικά αβλαβείς ουσίες δίνοντας ως τελικά προϊόντα το διοξείδιο του άνθρακα (CO2) και το νερό. Η προαναφερθείσα διαδικασία μπορεί να επιταχυνθεί με την χρήση ορισμένων θρεπτικών συστατικών όπως ο φώσφορος και το άζωτο, τα οποία δρουν στην διεπιφάνεια  OIL-WATER (νερού-πετρελαίου) και ευνοούν την ανάπτυξη των μικροοργανισμών.
Στην παρούσα διπλωματική μελετήθηκε ο τρόπος με τον οποίον κάποια λιπόφιλα φυσικά και χημικά λιπάσματα όπως η λεκιθίνη, το Basfoliar Avant Natur SL αλλά και ένα surfactant (επιφανειακά ενεργή ουσία) επιδρούν στην αποτελεσματικότητα της βιοαποδόμησης του πετρελαίου. Η εκτίμηση στηρίχθηκε στις μεταβολές της συγκέντρωσης  χαρακτηριστικών συστατικών του πετρελαίου και πιο συγκεκριμένα των κανονικών αλκανίων, των αρωματικών συστατικών και των ισοπρενοειδών.
Entanglement entropy scaling of noisy random quantum circuits in two dimensions
Creators: name: Zhang, Meng
name: Wang, Chao
name: Dong, Shaojun
name: Zhang, Hao
name: Han, Yongjian
name: He, Lixin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Whether noisy quantum devices without error correction can provide quantum advantage over classical computers is a critical issue of current quantum computation. In this work, the random quantum circuits, which are used as the paradigm model to demonstrate quantum advantage, are simulated with depolarizing noise on experiment relevant two-dimensional architecture. With comprehensive numerical simulation and theoretical analysis, we find that the maximum achievable operator entanglement entropy, which indicates maximal simulation cost, has area law scaling with the system size for constant noise rate. On the other hand, we also find that the maximum achievable operator entanglement entropy has power law scaling with the noise rate for fixed system size, and the volume law scaling can be obtained only if the noise rate decreases when system size increase.
Double-Disk Dark Matter
Creators: name: Fan, JiJi
name: Katz, Andrey
name: Randall, Lisa
name: Reece, Matthew
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Based on observational constraints on large scale structure and halo structure, dark matter is generally taken to be cold and essentially collisionless. On the other hand, given the large number of particles and forces in the visible world, a more complex dark sector could be a reasonable or even likely possibility. This hypothesis leads to testable consequences, perhaps portending the discovery of a rich hidden world neighboring our own. We consider a scenario that readily satisfies current bounds that we call Partially Interacting Dark Matter (PIDM). This scenario contains self-interacting dark matter, but it is not the dominant component. Even if PIDM contains only a fraction of the net dark matter density, comparable to the baryonic fraction, the subdominant component's interactions can lead to interesting and potentially observable consequences. Our primary focus will be the special case of Double-Disk Dark Matter (DDDM), in which self-interactions allow the dark matter to lose enough energy to lead to dynamics similar to those in the baryonic sector. We explore a simple model in which DDDM can cool efficiently and form a disk within galaxies, and we evaluate some of the possible observational signatures. The most prominent signal of such a scenario could be an enhanced indirect detection signature with a distinctive spatial distribution. Even though subdominant, the enhanced density at the center of the galaxy and possibly throughout the plane of the galaxy can lead to large boost factors, and could even explain a signature as large as the 130 GeV Fermi line. Such scenarios also predict additional dark radiation degrees of freedom that could soon be detectable and would influence the interpretation of future data, such as that from Planck and from the Gaia satellite. We consider this to be the first step toward exploring a rich array of new possibilities for dark matter dynamics.
description: 37 pages, 13 figures; v2: references added, appearing in Physics of the Dark Universe
Two combined methods for the global solution of implicit semilinear differential equations with the use of spectral projectors and Taylor expansions
Creators: name: Filipkovska, M. S.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65L80, 65L20, 65L70, 34A09, 34A12, 34D23, 47N40

description: Two combined numerical methods for solving semilinear differential-algebraic equations (DAEs) are obtained and their convergence is proved. The comparative analysis of these methods is carried out and conclusions about the effectiveness of their application in various situations are made. In comparison with other known methods, the obtained methods require weaker restrictions for the nonlinear part of the DAE. Also, the obtained methods enable to compute approximate solutions of the DAEs on any given time interval and, therefore, enable to carry out the numerical analysis of global dynamics of mathematical models described by the DAEs. The examples demonstrating the capabilities of the developed methods are provided. To construct the methods we use the spectral projectors, Taylor expansions and finite differences. Since the used spectral projectors can be easily computed, to apply the methods it is not necessary to carry out additional analytical transformations.
Simulation of the Majorana equation in circuit QED
Creators: name: Liu, Sheng
name: Shan, Chuan-Jia
name: Zhang, Zhi-Ming
name: Xue, Zheng-Yuan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a scheme to simulate the 1D Majorana equation with two Cooper pair boxes coupled to a 1D superconducting transmission line resonator, where strong coupling limit can be achieved. With proper chosen of systematic parameters, we are able to engineer different kinds of interaction, which is indispensable in simulating the Majorana equation in an enlarged real Hilbert space. Measurement of the conserved observable of pseudo-helicity via transmission spectrum of the cavity field can verify the simulated Majorana wave function. The measurement results are experimentally resolvable based on our estimation with conservative parameters.
description: first submitted on March 2012; v2 published version