cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Interplay between numerical relativity and perturbation theory : finite size effects
Creators: name: Islam, Tousif
name: Khanna, Gaurav
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We investigate the interplay between numerical relativity (NR) and point-particle black hole perturbation theory (ppBHPT) in the comparable mass ratio regime. In the ppBHPT framework, the secondary black hole is treated as a point particle, neglecting its finite size. Our study focuses on addressing the missing finite size effect in the ppBHPT framework and proposing a method for incorporating the size of the secondary into the perturbation theory framework. We demonstrate that by considering the secondary as a finite size object, the BHPT waveforms closely match NR waveforms. Additionally, we revisit the $α$-$β$ scaling technique, which was previously introduced by Islam et al, as a means to effectively match ppBHPT waveforms to NR waveforms. We further analyze the scaling procedure and decompose it into different components, attributing them to various effects, including the corrections arising from the finite size of the secondary black hole.
description: 12 pages, 10 figures
A Propositional Linear Time Logic with Time Flow Isomorphic to ω^2
Creators: name: Marinković, Bojan
name: Ognjanović, Zoran
name: Doder, Dragan
name: Perović, Aleksandar
Publisher: name: arXiv
Year: 2013
Subjects: subject: Logic (math.LO)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Primarily guided with the idea to express zero-time transitions by means of temporal propositional language, we have developed a temporal logic where the time flow is isomorphic to ordinal $ω^2$ (concatenation of $ω$ copies of $ω$). If we think of $ω^2$ as lexicographically ordered $ω\times ω$, then any particular zero-time transition can be represented by states whose indices are all elements of some $\{n\}\timesω$. In order to express non-infinitesimal transitions, we have introduced a new unary temporal operator $[ω] $ ($ω$-jump), whose effect on the time flow is the same as the effect of $α\mapsto α+ω$ in $ω^2$. In terms of lexicographically ordered $ω\times ω$, $[ω] ϕ$ is satisfied in $\ < i,j\ >$-th time instant iff $ϕ$ is satisfied in $\ < i+1,0\ >$-th time instant. Moreover, in order to formally capture the natural semantics of the until operator $\mathtt U$, we have introduced a local variant $\mathtt u$ of the until operator. More precisely, $ϕ\,\mathtt u ψ$ is satisfied in $\ < i,j\ >$-th time instant iff $ψ$ is satisfied in $\ < i,j+k\ >$-th time instant for some nonnegative integer $k$, and $ϕ$ is satisfied in $\ < i,j+l\ >$-th time instant for all $0\leqslant l
Nitsche's method for two and three dimensional NURBS patch coupling
Creators: name: Nguyen, Vinh Phu
name: Kerfriden, Pierre
name: Brino, Marco
name: Bordas, Stephane
name: Bonisoli, Elvio
Publisher: name: arXiv
Year: 2013
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: A Nitche's method is presented to couple non-conforming two and three dimensional NURBS (Non Uniform Rational B-splines) patches in the context of isogeometric analysis (IGA). We present results for elastic stress analyses under the static condition of two and three dimensional NURBS geometries. The contribution fills the gap in the literature and enlarges the applicability of NURBS-based isogeometric analysis.
Four-coloured Spin-wave Excitations in Multiferroic Materials
Creators: name: Kezsmarki, Istvan
name: Szaller, David
name: Bordacs, Sandor
name: Murakawa, Hiroshi
name: Tokura, Yoshinori
name: Engelkamp, Hans
name: Room, Toomas
name: Nagel, Urmas
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The optical magnetoelectric effect, which is an inherent attribute of the spin excitations in multiferroics, drastically changes their optical properties compared to conventional materials where light-matter interaction is expressed only by the dielectric permittivity and magnetic permeability. Our polarized absorption experiments performed on multiferroic Ca2CoSi2O7 and Ba2CoGe2O7 in the THz spectral range demonstrate that such magnetoeletric spin excitations show quadrochroism, i.e. they have different colours for all the four combinations of the two propagation directions (forward or backward) and the two orthogonal polarizations of a light beam. We found that quadrochroism can give rise to peculiar optical properties, such as one-way transparency and zero-reflection of these excitations, which can open a new horizon in photonics. One-way transparency is also related to the static magnetoelectric phenomena, hence, these optical studies can provide guidelines for the systematic synthesis of new materials with large dc magnetoelectric effect.
Organisational Identifier und PIDs
Creators: name: Schirrwagen, Jochen
name: Vierkant, Paul
Publisher: name: Zenodo
Year: 2020
Subjects: KDSF
Standard
Germany
Research Information
Research Information Systems
Research Reporting
Organizational Identifier
ORCID

description: ● Überblick Organisations-IDs
 ● Research Organization Registry
 ● ORCID in erweiterten Kontexten
 ● Organisations-IDs im Kontext der Forschungsinformation
Interplay between numerical-relativity and black hole perturbation theory in the intermediate-mass-ratio regime
Creators: name: Islam, Tousif
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We investigate the interplay between numerical relativity (NR) and point-particle black hole perturbation theory (ppBHPT) for quasi-circular non-spinning binary black holes in the intermediate mass ratio regime: 7<=q<=128 (where $q:=m_1/m_2$ is the mass ratio of the binary with m_1 and m_2 being the mass of the primary and secondary black hole respectively). Initially, we conduct a comprehensive comparison between the dominant (l,m) = (2,2) mode of the gravitational radiation obtained from state-of-the-art NR simulations and ppBHPT waveforms along with waveforms generated from recently developed NR-informed ppBHPT surrogate model, BHPTNRSur1dq1e4. This surrogate model employs a simple but non-trivial rescaling technique known as the $α$-$β$ scaling to effectively match ppBHPT waveforms to NR in the comparable mass ratio regime. Subsequently, we analyze the amplitude and frequency differences between NR and ppBHPT waveforms to investigate the non-linearities, beyond adiabatic evolution, that are present during the merger stage of the binary evolution and propose fitting functions to describe these differences in terms of both the mass ratio and the symmetric mass ratio. Finally, we assess the performance of the $α$-$β$ scaling technique in the intermediate mass ratio regime.
description: 11 pages, 10 figures
Unitarity constraints for Yukawa couplings in the two Higgs doublet model type III
Creators: name: Castillo, Andres
name: Diaz, Rodolfo A.
name: Morales, John
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Unitarity constraints for Yukawa couplings are considered in the Two Higgs Doublet Model type III, by using a general expansion in partial waves for fermionic scattering processes. Constraints over general Flavor Changing Neutral Currents are found from that systematic, such bounds compete with those coming from Lagrangian perturbativity requirement but are weaker than those imposed from phenomenological processes and precision tests. Nevertheless, for bounds based on unitarity the number of assumptions is the lowest among phenomenological and theoretical limits. Indeed, these new theoretical constraints are independent of scalar masses or mixing angles for this extended Higgs sector, making them less model dependent.
description: 14 pages, 2 figures, LaTeX2e
Understanding Revision Behavior in Adaptive Writing Support Systems for Education
Creators: name: Mouchel, Luca
name: Wambsganss, Thiemo
name: Mejia-Domenzain, Paola
name: Käser, Tanja
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: Revision behavior in adaptive writing support systems is an important and relatively new area of research that can improve the design and effectiveness of these tools, and promote students' self-regulated learning (SRL). Understanding how these tools are used is key to improving them to better support learners in their writing and learning processes. In this paper, we present a novel pipeline with insights into the revision behavior of students at scale. We leverage a data set of two groups using an adaptive writing support tool in an educational setting. With our novel pipeline, we show that the tool was effective in promoting revision among the learners. Depending on the writing feedback, we were able to analyze different strategies of learners when revising their texts, we found that users of the exemplary case improved over time and that females tend to be more efficient. Our research contributes a pipeline for measuring SRL behaviors at scale in writing tasks (i.e., engagement or revision behavior) and informs the design of future adaptive writing support systems for education, with the goal of enhancing their effectiveness in supporting student writing. The source code is available at https://github.com/lucamouchel/Understanding-Revision-Behavior.
description: 8 pages, Conference Paper
Refined masses and distance of the young binary Haro 1-14 C
Creators: name: Bouquin, Jean-Baptiste Le
name: Monin, J. -L.
name: Berger, Jean-Philippe
name: Benisty, M.
name: Prato, L.
name: Schaefer, G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We aim to refine the dynamical masses of the individual component of the low-mass pre-main sequence binary Haro 1-14 C. We combine the data of the preliminary orbit presented previously with new interferometric observations obtained with the four 8m telescopes of the Very Large Telescope Interferometer. The derived masses are $M_a=0.905\pm0.043\,\Msun$ and $M_b=0.308\pm0.011\,\Msun$ for the primary and secondary components, respectively. This is about five times better than the uncertainties of the preliminary orbit. Moreover, the possibility of larger masses is now securely discarded. The new dynamical distance, $d=96\pm\,9\,$pc, is smaller than the distance to the Ophiuchus core with a significance of $2.6\,σ$. Fitting the spectral energy distribution yields apparent diameters of $ϕ_a=0.13\pm0.01\mas$ and $ϕ_b=0.10\pm0.01\mas$ (corresponding to $\Ra=1.50\,\Rsun$ and $\Rb=1.13\,\Rsun$) and a visual extinction of $A_v\approx1.75$. Although the revised orbit has a nearly edge-on geometry, the system is unlikely to be a long-period eclipsing binary. The secondary in Haro~1-14C is one of the few low-mass, pre-main sequence stars with an accurately determined dynamical mass and distance.
Guidelines for Maintaining Academic Integrity When Using AI Tools
Creators: name: Sy, Peter
Publisher: name: figshare
Year: 2023
Subjects: Artificial intelligence not elsewhere classified
Education systems not elsewhere classified

description: If you've considered using generative AI tools like large language models (e.g., ChatGPT, Perplexity, Bard), search (e.g., Semantic Scholar, Bing), synthetic media (e.g., Synthesia, Midjourney, Descript), coding (e.g, Github Copilot, ChatGPT) to assist you in your academic work, it's important to follow certain guidelines to help maintain academic integrity.
Patch-wise Quadrature of Trimmed Surfaces in Isogeometric Analysis
Creators: name: Loibl, Michael
name: Leonetti, Leonardo
name: Reali, Alessandro
name: Kiendl, Josef
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Numerical Analysis (math.NA)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: This work presents an efficient quadrature rule for shell analysis fully integrated in CAD by means of Isogeometric Analysis (IGA). General CAD-models may consist of trimmed parts such as holes, intersections, cut-offs etc. Therefore, IGA should be able to deal with these models in order to fulfil its promise of closing the gap between design and analysis. Trimming operations violate the tensor-product structure of the used Non-Uniform Rational B-spline (NURBS) basis functions and of typical quadrature rules. Existing efficient patch-wise quadrature rules consider actual knot vectors and are determined in 1D. They are extended to further dimensions by means of a tensor-product. Therefore, they are not directly applicable to trimmed structures. The herein proposed method extends patch-wise quadrature rules to trimmed surfaces. Thereby, the number of quadrature points can be signifficantly reduced. Geometrically linear and non-linear benchmarks of plane, plate and shell structures are investigated. The results are compared to a standard trimming procedure and a good performance is observed.
Discovery of a 760 nm P Cygni line in AT2017gfo: Identification of yttrium in the kilonova photosphere
Creators: name: Sneppen, Albert
name: Watson, Darach
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Neutron star mergers are believed to be a major cosmological source of rapid neutron-capture elements. The kilonovae associated with neutron star mergers have to date yielded only a single well-identified spectral signature: the P Cygni line of Sr$^+$ at about 1$μ$m in the spectra of the optical transient, AT2017gfo. Such P Cygni lines are important, because they provide significant information not just potentially on the elemental composition of the merger ejecta, but also on the velocity, geometry, and abundance stratification of the explosion. In this paper we show evidence for a previously unrecognised P Cygni line in the spectra of AT2017gfo that emerges several days after the explosion, located at $λ\approx 760\,$nm. We show that the feature is well-reproduced by 4d$^2$-4d5p transitions of Y$^+$, which have a weighted mean wavelength around 760-770 nm, with the most prominent line at 788.19 nm. While the observed line is weaker than the Sr$^+$ feature, the velocity stratification of the new line provides an independent constraint on the expansion rate of the ejecta similar to the constraints from Sr$^+$.
description: 11 pages, 7 figures, Accepted in A&A
Toward a Physical Understanding of Galaxy-Halo Alignment
Creators: name: Xu, Kun
name: Jing, Y. P.
name: Zhao, Donghai
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We investigate the alignment of galaxy and halo orientations using the TNG300-1 hydrodynamical simulation. Our analysis reveals that the distribution of the 2D misalignment angle $θ_{\rm{2D}}$ can be well described by a truncated shifted exponential (TSE) distribution with only {\textit{one}} free parameter across different redshifts and galaxy/halo properties. We demonstrate that the galaxy-ellipticity (GI) correlations of galaxies can be reproduced by perturbing halo orientations with the obtained $θ_{\rm{2D}}$ distribution, with only a small bias ($<3^{\circ}$) possibly arising from unaccounted couplings between $θ_{\rm{2D}}$ and other factors. We find that both the 2D and 3D misalignment angles $θ_{\rm{2D}}$ and $θ_{\rm{3D}}$ decrease with ex situ stellar mass fraction $F_{\rm{acc}}$, halo mass $M_{\rm{vir}}$ and stellar mass $M_{*}$, while increasing with disk-to-total stellar mass fraction $F_{\rm{disk}}$ and redshift. These dependences are in good agreement with our recent observational study based on the BOSS galaxy samples. Our results suggest that $F_{\rm{acc}}$ is a key factor in determining the galaxy-halo alignment. Grouping galaxies by $F_{\rm{acc}}$ nearly eliminates the dependence of $θ_{\rm{3D}}$ on $M_{\rm{vir}}$ for all three principle axes, and also reduces the redshift dependence. For $θ_{\rm{2D}}$, we find a more significant redshift dependence than for $θ_{\rm{3D}}$ even after controlling $F_{\rm{acc}}$, which may be attributed to the evolution of galaxy and halo shapes. Our findings present a valuable model for observational studies and enhance our understanding of galaxy-halo alignment.
description: 19 pages, 12 figures, Published in ApJ
Cooling molecular vibrations with shaped laser pulses: Optimal control theory exploiting the timescale separation between coherent excitation and spontaneous emission
Creators: name: Reich, Daniel M.
name: Koch, Christiane P.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Laser cooling of molecules employing broadband optical pumping involves a timescale separation between laser excitation and spontaneous emission. Here, we optimize the optical pumping step using shaped laser pulses. We derive two optimization functionals to drive population into those excited state levels that have the largest spontaneous emission rates to the target state. We show that, when using optimal control, laser cooling of molecules works even if the Franck-Condon map governing the transitions is preferential to heating rather than cooling. Our optimization functional is also applicable to the laser cooling of other degrees of freedom provided the cooling cycle consists of coherent excitation and dissipative deexcitation steps whose timescales are separated.
Circular string in a Black p-brane leading to chaos
Creators: name: Dutta, Pinaki
name: Panigrahi, Kamal L.
name: Singh, Balbeer
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider a pulsating string near a non-extremal black p-brane (p=5 and p=6) and investigate the chaos in the corresponding string dynamics by examining the Fast Lyapunov indicator(FLI) and Poincare section. In our system, the energy and the charge play the role of control parameters. For generic values of these parameters, the numerical results show that the dynamics primarily fall into three modes: capture, escape to infinity, and quasiperiodic depending on the initial location (near to or far away from the black brane horizon) of the string. Finally, probing for different values of the winding number (n) the dynamics turns out to be sensitive to n. In particular, we observe the point particle (n=0) scenario to be integrable whereas at higher n the dynamics seems to be chaotic.
description: 26 pages, 45 figures
Topological transitions in a model with Particle-Hole symmetry, Pancharatnam-Berry Curvature and Dirac Points
Creators: name: Sriluckshmy, P. V.
name: Mishra, Archana
name: Hassan, S. R.
name: Shankar, R.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the topology and geometry of a fermionic model on the honeycomb lattice with spin-dependent hopping which breaks the time-reversal and charge-conjugation symmetries but preserves their composition. We show that in such a case the Zak phases are topological invariants that characterize the semi-metallic state at half-filling and determine the edge state structure. As the strength of the spin-dependent hopping varies, the model shows several Lifshitz transitions corresponding to creation and merging of multiple Dirac points. We discuss the possible realization of this model in cold atom systems and propose experimental signals of detecting the Dirac points and Pancharathnam-Berry curvature of the bands.
description: 13 pages, 17 figures; movies at http://www.youtube.com/playlist?list=PLINihIBfmWkB6h86e8URUdTbdxemY83Vc
Optically active mechanical modes of tapered optical fibers
Creators: name: Wuttke, Chrisitan
name: Cole, Garrett D.
name: Rauschenbeutel, Arno
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Tapered optical fibers with a nanofiber waist are widely used tools for efficient coupling of light to photonic devices or quantum emitters via the nanofiber's evanescent field. In order to ensure well-controlled coupling, the phase and polarization of the nanofiber guided light field have to be stable. Here, we show that in typical tapered optical fibers these quantities exhibit high-frequency thermal fluctuations. They originate from high-Q torsional oscillations that opto-mechanically couple to the nanofiber-guided light. We present a simple ab-initio theoretical model that quantitatively explains the torsional mode spectrum and that can be used to design tapered optical fibers with tailored mechanical properties.
Evaluating the Task Generalization of Temporal Convolutional Networks for Surgical Gesture and Motion Recognition using Kinematic Data
Creators: name: Hutchinson, Kay
name: Reyes, Ian
name: Li, Zongyu
name: Alemzadeh, Homa
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Fine-grained activity recognition enables explainable analysis of procedures for skill assessment, autonomy, and error detection in robot-assisted surgery. However, existing recognition models suffer from the limited availability of annotated datasets with both kinematic and video data and an inability to generalize to unseen subjects and tasks. Kinematic data from the surgical robot is particularly critical for safety monitoring and autonomy, as it is unaffected by common camera issues such as occlusions and lens contamination. We leverage an aggregated dataset of six dry-lab surgical tasks from a total of 28 subjects to train activity recognition models at the gesture and motion primitive (MP) levels and for separate robotic arms using only kinematic data. The models are evaluated using the LOUO (Leave-One-User-Out) and our proposed LOTO (Leave-One-Task-Out) cross validation methods to assess their ability to generalize to unseen users and tasks respectively. Gesture recognition models achieve higher accuracies and edit scores than MP recognition models. But, using MPs enables the training of models that can generalize better to unseen tasks. Also, higher MP recognition accuracy can be achieved by training separate models for the left and right robot arms. For task-generalization, MP recognition models perform best if trained on similar tasks and/or tasks from the same dataset.
description: 8 pages, 4 figures, 6 tables. To be published in IEEE Robotics and Automation Letters (RA-L)
Energy flow during relaxation in an electron-phonon system with multiple modes: A nonequilibrium Green's function study
Creators: name: Inayoshi, Ken
name: Koga, Akihisa
name: Murakami, Yuta
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate an energy flow in an extended Holstein model describing electron systems coupled to hot-phonons and heat-bath phonons. To analyze the relaxation process after the photo-excitation of electrons, we employ the nonequilibrium dynamical mean-field theory (DMFT). We find the backward energy flow during the relaxation, where the direction of energy transfer between electrons and hot-phonons is reversed. To clarify the microscopic mechanism of the backward energy flow, we introduce the approximated energy flows, which are calculated with the gradient and quasiparticle approximations and are related to the nonequilibrium distribution functions. We compare these approximated energy flows with the full energy flows calculated from the nonequilibrium DMFT. We find that, in the weak electron-hot-phonon coupling regime, the full and approximated energy flows are almost the same, meaning that the relaxation dynamics can be correctly understood in terms of the nonequilibrium distribution functions. As the strength of the electron-hot-phonon coupling increases, the approximated energy flow fails to qualitatively reproduce the full energy flow. This indicates that the microscopic origin of the energy flow cannot be solely explained by the nonequilibrium distribution functions. By comparing the energy flows with different levels of approximation, we reveal the role of the gradient and quasiparticle approximations.
description: 20 pages, 12 figures
Introduction to Dirac materials and topological insulators
Creators: name: Cayssol, J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a short pedagogical introduction to the physics of Dirac materials, restricted to graphene and two- dimensional topological insulators. We start with a brief reminder of the Dirac and Weyl equations in the particle physics context. Turning to condensed matter systems, semimetallic graphene and various Dirac insulators are introduced, including the Haldane and the Kane-Mele topological insulators. We also discuss briefly experimental realizations in materials with strong spin-orbit coupling.
description: 24 pages, 8 figures; review submitted to topical issue of "Comptes Rendus de l'Acad\'emie des Sciences (Physique)" devoted to topological insulators and Dirac matter. Pre-publication version; comments are invited
End-to-End Learnable Multi-Scale Feature Compression for VCM
Creators: name: Kim, Yeongwoong
name: Jeong, Hyewon
name: Yu, Janghyun
name: Kim, Younhee
name: Lee, Jooyoung
name: Jeong, Se Yoon
name: Kim, Hui Yong
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Image and Video Processing (eess.IV)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The proliferation of deep learning-based machine vision applications has given rise to a new type of compression, so called video coding for machine (VCM). VCM differs from traditional video coding in that it is optimized for machine vision performance instead of human visual quality. In the feature compression track of MPEG-VCM, multi-scale features extracted from images are subject to compression. Recent feature compression works have demonstrated that the versatile video coding (VVC) standard-based approach can achieve a BD-rate reduction of up to 96% against MPEG-VCM feature anchor. However, it is still sub-optimal as VVC was not designed for extracted features but for natural images. Moreover, the high encoding complexity of VVC makes it difficult to design a lightweight encoder without sacrificing performance. To address these challenges, we propose a novel multi-scale feature compression method that enables both the end-to-end optimization on the extracted features and the design of lightweight encoders. The proposed model combines a learnable compressor with a multi-scale feature fusion network so that the redundancy in the multi-scale features is effectively removed. Instead of simply cascading the fusion network and the compression network, we integrate the fusion and encoding processes in an interleaved way. Our model first encodes a larger-scale feature to obtain a latent representation and then fuses the latent with a smaller-scale feature. This process is successively performed until the smallest-scale feature is fused and then the encoded latent at the final stage is entropy-coded for transmission. The results show that our model outperforms previous approaches by at least 52% BD-rate reduction and has $\times5$ to $\times27$ times less encoding time for object detection...
description: 13 pages, accepted by IEEE Transactions on Circuits and Systems for Video Technology
Thin-Shell Gravastar Model in $f(Q,T)$ Gravity
Creators: name: Pradhan, Sneha
name: Mohanty, Debasmita
name: Sahoo, P. K.
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In the last few decades, gravastars have been proposed as an alternative to black holes. The stability of the gravastar has been studied in many modified theories of gravity along with Einstein's GR. The $f(Q,T)$ gravity, a successfully modified theory of gravity for describing the current accelerated expansion of the Universe, has been used in this article to study gravastar in different aspects. According to Mazur and Mottola (Proc. Natl. Acad. Sci 101, 9545 (2004)), it has three regions with three different equations of state. Here in this work, we have studied the interior of the gravastar by considering the $p=-ρ$ EoS to describe the dark sector for the interior region. The next region is a thin shell of ultrarelativistic stiff fluid, in which we have investigated several physical properties, viz., the proper length, energy, entropy, surface energy density, etc. In addition, we have studied the surface redshift and speed of sound to check the potential stability of our proposed thin-shell gravastar model. Apart from that, we have used the entropy maximization technique to verify the stability of the gravastar model. The gravastar's outer region is a complete vacuum described by exterior Schwarzschild geometry. Finally, we have presented a stable gravastar model which is singularity-free and devoid of any incompleteness in classical black hole theory.
description: Chinese Physics C published version
Constraints on the ghost-free parity-violating gravity from Laser-ranged Satellites
Creators: name: Qiao, Jin
name: Li, Zhao
name: Ji, Ran
name: Zhu, Tao
name: Li, Guoliang
name: Zhao, Wen
name: Chen, Jiming
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: This paper explores the evolutionary behavior of the Earth-satellite binary system within the framework of the ghost-free parity-violating gravity and the corresponding discussion on the parity-violating effect from the laser-ranged satellites. For this purpose, we start our study with the Parameterized Post-Newtonian (PPN) metric of this gravity theory to study the orbital evolution of the satellites in which the spatial-time sector of the spacetime is modified due to the parity violation. With this modified PPN metric, we calculate the effects of the parity-violating sector of metrics on the time evolution of the orbital elements for an Earth-satellite binary system. We find that among the five orbital elements, the parity violation has no effect on the semi-latus rectum, while the eccentricity and ascending node are affected only in a periodic manner. These three orbital elements are the same as the results of general relativity and are also consistent with the observations of the present experiment. In particular, parity violation produces non-zero corrections to the eccentricity and pericenter, which will accumulate with the evolution of time, indicating that the parity violation of gravity produces observable secular effects. The observational constraint on the parity-violating effect is derived by confronting the theoretical prediction with the observation by the LAGEOS II pericenter advance, giving a constraint on the parity-violating parameter space from the satellite experiments.
description: 13 pages, no figure
Predicting the steady state thickness of passive films in order to prevent degradations of implant
Creators: name: Geringer, Jean
name: Taylor, Mathew L.
name: Macdonald, Digby D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Some implants have approximately a lifetime of 15 years. The femoral stem, for example, should be made of 316L/316LN stainless steel. Fretting corrosion, friction under small displacements, should occur during human gait, due to repeated loadings and un-loadings, between stainless steel and bone for instance. Some experimental investigations of fretting corrosion have been practiced. As well known, metallic alloys and especially stainless steels are covered with a passive film that prevents from the corrosion and degradation. This passive layer of few nanometers, at ambient temperature, is the key of our civilization according to some authors. This work is dedicated to predict the passive layer thicknesses of stainless steel under fretting corrosion with a specific emphasis on the role of proteins. The model is based on the Point Defect Model (micro scale) and an update of the model on the friction process (micro-macro scale). Genetic algorithm was used for finding solution of the problem. The major results are, as expected from experimental results, albumin prevents from degradation at the lowest concentration of chlorides; an incubation time is necessary for degrading the passive film; under fretting corrosion and high concentration of chlorides the passive behavior is annihilated.
A Schrödinger Equation for Evolutionary Dynamics
Creators: name: Ao, Vi D.
name: Tran, Duy V.
name: Pham, Kien T.
name: Nguyen, Duc M.
name: Tran, Huy D.
name: Do, Tuan K.
name: Do, Van H.
name: Phan, Trung V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: We establish an analogy between the Fokker-Planck equation describing evolutionary landscape dynamics and the Schrödinger equation which characterizes quantum mechanical particles, showing how a population with multiple genetic traits evolves analogously to a wavefunction under a multi-dimensional energy potential in imaginary time. Furthermore, we discover within this analogy that the stationary population distribution on the landscape corresponds exactly to the ground-state wavefunction. This mathematical equivalence grants entry to a wide range of analytical tools developed by the quantum mechanics community, such as the Rayleigh-Ritz variational method and the Rayleigh-Schrödinger perturbation theory, allowing us to not only make reasonable quantitative assessments but also explore fundamental biological inquiries. We demonstrate the effectiveness of these tools by estimating the population success on landscapes where precise answers are elusive, and unveiling the ecological consequences of stress-induced mutagenesis -- a prevalent evolutionary mechanism in pathogenic and neoplastic systems. We show that, even in a unchanging environment, a sharp mutational burst resulting from stress can always be advantageous, while a gradual increase only enhances population size when the number of relevant evolving traits is limited. Our interdisciplinary approach offers novel insights, opening up new avenues for deeper understanding and predictive capability regarding the complex dynamics of evolving populations.
On-surface synthesis and characterization of Teranthene and Hexanthene: Ultrashort graphene nanoribbons with mixed armchair and zigzag edges
Creators: name: Barin, Gabriela Borin
name: Di Giovannantonio, Marco
name: Lohr, Thorsten G.
name: Mishra, Shantanu
name: Kinikar, Amogh
name: Perrin, Mickael L.
name: Overbeck, Jan
name: Calame, Michel
name: Feng, Xinliang
name: Fasel, Roman
name: Ruffieux, Pascal
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Graphene nanoribbons (GNRs) exhibit a broad range of physicochemical properties that critically depend on their width and edge topology. While the chemically stable GNRs with armchair edges (AGNRs) are semiconductors with width-tunable band gap, GNRs with zigzag edges (ZGNRs) host spin-polarized edge states, which renders them interesting for applications in spintronic and quantum technologies. However, these states significantly increase their reactivity. For GNRs fabricated via on-surface synthesis under ultrahigh vacuum conditions on metal substrates, the expected reactivity of zigzag edges is a serious concern in view of substrate transfer and device integration under ambient conditions, but corresponding investigations are scarce. Using 10-bromo-9,9':10',9''-teranthracene as a precursor, we have thus synthesized hexanthene (HA) and teranthene (TA) as model compounds for ultrashort GNRs with mixed armchair and zigzag edges, characterized their chemical and electronic structure by means of scanning probe methods, and studied their chemical reactivity upon air exposure by Raman spectroscopy. We present a detailed identification of molecular orbitals and vibrational modes, assign their origin to armchair or zigzag edges, and discuss the chemical reactivity of these edges based on characteristic Raman spectral features.
Magnetization near a constriction between BCS superconductors by spin-dependent tunneling
Creators: name: Entin-Wohlman, O.
name: Shekhter, R. I.
name: Jonson, M.
name: Aharony, A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Spin-dependent electron tunneling through a voltage-biased micro-constriction between two bulk superconductors is shown to create a static magnetization near the constriction and an ac Josephson-like spin current. Although spin-dependent tunneling generates quantum spin fluctuations even in the absence of a bias, the formation of spin-triplet Cooper pairs necessary for the creation of magnetization is blocked by destructive interference between different quasi-electron and quasi-hole tunneling channels, unless there is an asymmetry between the tunneling densities of states for electrons and holes. Breaking the symmetry in the electron-hole tunnel density of states and creating electron-hole tunneling imbalance by biasing the device destroys the destructive interference and enables triplet Cooper-pair formation. As a result, magnetizing the superconductor becomes possible. The role of the voltage in lifting the blockade hindering the spin-triplet Cooper pair formation is an example of an electrically-controlled dissipation-less spintronic phenomenon.
description: Changed title, added figures, published version
Doubling the Critical Current Density of High Temperature Superconducting Coated Conductors through Proton Irradiation
Creators: name: Jia, Y.
name: LeRoux, M.
name: Miller, D. J.
name: Wen, J. G.
name: Kwok, W. K.
name: Welp, U.
name: Rupich, M. W.
name: Li, X.
name: Sathyamurthy, S.
name: Fleshler, S.
name: Malozemoff, A. P.
name: Kayani, A.
name: Ayala-Valenzuela, O.
name: Civale, L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The in-field critical current of commercial YBa2Cu3O7 coated conductors can be substantially enhanced by post-fabrication irradiation with 4 MeV protons. Irradiation to a fluence of 8x10^16 p/cm^2 induces a near doubling of the critical current in fields of 6 T || c at a temperature of 27 K, a field and temperature range of interest for applications such as rotating machinery. A mixed pinning landscape of preexisting precipitates and twin boundaries and small, finely dispersed irradiation induced defects may account for the improved vortex pinning in high magnetic fields. Our data indicate that there is significant head-room for further enhancements.
description: 19 pages, 4 figures
Big-Bang is a Boundary Condition
Creators: name: Kaya, Ali
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: There is a common expectation that the big-bang singularity must be resolved in quantum gravity but it is not clear how this can be achieved. A major obstacle here is the difficulty of interpreting wave-functions in quantum gravity. The standard quantum mechanical framework requires a notion of time evolution and a proper definition of an invariant inner product having a probability interpretation, both of which are seemingly problematic in quantum gravity. We show that these two issues can actually be solved by introducing the embedding coordinates as dynamical variables à la Isham and Kuchar. The extended theory is identical to general relativity but has a larger group of gauge symmetries. The Wheeler-DeWitt equations describe the change of the wave-function from one arbitrary spacelike slice to another, however the constraint algebra makes this evolution purely kinematical and furthermore enforces the wave-function to be constrained in the subspace of zero-energy states. An inner product can also be introduced having all the necessary requirements. In this formalism big-bang appears as a finite field space boundary on which certain boundary conditions must be imposed for mathematical consistency. We explicitly illustrate this point both in the full theory and in the minisuperspace approximation.
description: v2: 16 pages, Revtex 4-1, to appear in Annals of Physics
Bayesian Model Selection in Complex Linear Systems, as Illustrated in Genetic Association Studies
Creators: name: Wen, Xiaoquan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Methodology (stat.ME)
subject: Quantitative Methods (q-bio.QM)
subject: Applications (stat.AP)
subject: FOS: Computer and information sciences
subject: FOS: Biological sciences

description: Motivated by examples from genetic association studies, this paper considers the model selection problem in a general complex linear model system and in a Bayesian framework. We discuss formulating model selection problems and incorporating context-dependent {\it a priori} information through different levels of prior specifications. We also derive analytic Bayes factors and their approximations to facilitate model selection and discuss their theoretical and computational properties. We demonstrate our Bayesian approach based on an implemented Markov Chain Monte Carlo (MCMC) algorithm in simulations and a real data application of mapping tissue-specific eQTLs. Our novel results on Bayes factors provide a general framework to perform efficient model comparisons in complex linear model systems.
ADAPTATION OF STATION DESIGN PARAMENTERS FOR ADDIS ABABA LIGHT RAILWAY IN ETHIOPIAN CONTEXT
Creators: name: KALEAB TESFAYE
Publisher: name: Zenodo
Year: 2018

description: Station is a basic production unit of railway transportation, integrating technical equipment relating to transportation. For the last couple of years investigations have been conducted in Ethiopia in railway site selection. One of that is the Addis Ababa light railway, where two alternative rights of way are seen. That is north- south corridor and East –west corridor of Addis Ababa which is about 34km.

An important subject in the planning of a new railway line is the design of the railway stations since they affect the capacity, flexibility and the safety of the rail transport system. The main objective of paper is to investigate how stations can be designed to align with the proposed high speed railway concepts on the line of the light railway based the topography, demography, climatic and economic conditions of the country. The focus in the report is to adapt parameters of station design and investigate how they are affected by the high speed railway concepts. This paper consists of a literature study similar to the subject. The knowledge gained is then used to suggest possible station platforms, station safety. Some aspects of station design that are investigated in the literature study are platforms, platform safety issues, necessary dimensions of platforms and stations.
Universal extension classes for $GL_2$
Creators: name: Drupieski, Christopher M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Representation Theory (math.RT)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 20G10

description: In this note we give a new existence proof for the universal extension classes for $GL_2$ previously constructed by Friedlander and Suslin via the theory of strict polynomial functors. The key tool in our approach is a calculation of Parker showing that, for suitable choices of coefficient modules, the Lyndon--Hochschild--Serre spectral sequence for $SL_2$ relative to its first Frobenius kernel stabilizes at the $E_2$-page. Consequently, we obtain a new proof that if $G$ is an infinitesimal subgroup scheme of $GL_2$, then the cohomology ring $\Hbul(G,k)$ of $G$ is a finitely-generated noetherian $k$-algebra.
description: 9 pages
Transforming Sentiment Analysis in the Financial Domain with ChatGPT
Creators: name: Fatouros, Georgios
name: Soldatos, John
name: Kouroumali, Kalliopi
name: Makridis, Georgios
name: Kyriazis, Dimosthenis
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences
subject: 68T01, 68T50, 91B28, 91B30

description: Financial sentiment analysis plays a crucial role in decoding market trends and guiding strategic trading decisions. Despite the deployment of advanced deep learning techniques and language models to refine sentiment analysis in finance, this study breaks new ground by investigating the potential of large language models, particularly ChatGPT 3.5, in financial sentiment analysis, with a strong emphasis on the foreign exchange market (forex). Employing a zero-shot prompting approach, we examine multiple ChatGPT prompts on a meticulously curated dataset of forex-related news headlines, measuring performance using metrics such as precision, recall, f1-score, and Mean Absolute Error (MAE) of the sentiment class. Additionally, we probe the correlation between predicted sentiment and market returns as an additional evaluation approach. ChatGPT, compared to FinBERT, a well-established sentiment analysis model for financial texts, exhibited approximately 35\% enhanced performance in sentiment classification and a 36\% higher correlation with market returns. By underlining the significance of prompt engineering, particularly in zero-shot contexts, this study spotlights ChatGPT's potential to substantially boost sentiment analysis in financial applications. By sharing the utilized dataset, our intention is to stimulate further research and advancements in the field of financial services.
description: 10 pages, 8 figures, Machine Learning with Applications (2023)
Efficient Non-Learning Similar Subtrajectory Search
Creators: name: Jin, Jiabao
name: Cheng, Peng
name: Chen, Lei
name: Lin, Xuemin
name: Zhang, Wenjie
Publisher: name: arXiv
Year: 2023
Subjects: subject: Databases (cs.DB)
subject: FOS: Computer and information sciences

description: Similar subtrajectory search is a finer-grained operator that can better capture the similarities between one query trajectory and a portion of a data trajectory than the traditional similar trajectory search, which requires the two checked trajectories are similar to each other in whole. Many real applications (e.g., trajectory clustering and trajectory join) utilize similar subtrajectory search as a basic operator. It is considered that the time complexity is O(mn^2) for exact algorithms to solve the similar subtrajectory search problem under most trajectory distance functions in the existing studies, where m is the length of the query trajectory and n is the length of the data trajectory. In this paper, to the best of our knowledge, we are the first to propose an exact algorithm to solve the similar subtrajectory search problem in O(mn) time for most of widely used trajectory distance functions (e.g., WED, DTW, ERP, EDR and Frechet distance). Through extensive experiments on three real datasets, we demonstrate the efficiency and effectiveness of our proposed algorithms.
description: VLDB 2023