cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Radio halos and relics from extended cosmic-ray ion distributions with strong diffusion in galaxy clusters
Creators: name: Keshet, Uri
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: A joint hadronic model is shown to quantitatively explain the observations of diffuse radio emission from galaxy clusters in the form of minihalos, giant halos, relics, and their hybrid, transitional stages. Cosmic-ray diffusion of order $D\sim 10^{31\text{--}32}\text{ cm}^2\text{ s}^{-1}$, inferred independently from relic energies, the spatial variability of giant-halo spectra, and the spectral evolution of relics, reproduces the observed spatio-spectral distributions, explains the recently discovered mega-halos as enhanced peripheral magnetization, and quenches electron (re)acceleration by weak shocks or turbulence. For instance, the hard-to-soft evolution along secondary-electron diffusion explains both the soft spectra in most halo peripheries and relic downstreams, and the hard spectra in most halo centres and relic edges, where the photon index can reach $α\simeq -0.5$ regardless of the Mach number $\mathcal{M}$ of the coincident shock. Such spatio-spectral modeling, recent $γ$-ray observations, and additional accumulated evidence are thus shown to support a previous claim (Keshet 2010) that the seamless transitions among minihalos, giant halos, and relics, their similar energetics, integrated spectra, and delineating discontinuities, the inconsistent $\mathcal{M}$ inferred from radio vs. X-rays in leptonic models, and additional observations, all indicate that these diffuse radio phenomena are manifestations of the same cosmic-ray ion population, with no need to invoke less natural alternatives.
description: To appear in MNRAS; Appendix E added
Simulation and Implementation of Distributed Sensor Network for Radiation Detection
Creators: name: Liu, Annie Hsin-Wen
Publisher: name: California Institute of Technology
Year: 2010
Subjects: robotics
optimization
radiation detection
Computer Science
distributed sensor network

description: The problem of monitoring and searching for threats that involve radiological weapons is extremely challenging because of he high variance in background radiation, the presence of benign sources and possible shielding on harmful sources. We present in this thesis a collection of algorithms and analysis that center around the problem of radiation detection with a distributed sensor network. We studied the basic characteristics of a radiation sensor network and focused on the tradeoffs between false positive rate, true positive rate, and time to detect one or more radiation sources in a large area. Three major results came out from this thesis work. First of all, we developed a simulation platform modified from multiplayer game engine that is capable of simulating realistic data in highly dynamic environments. Secondly, we provided mathematical and simulation analyses regarding critical system parameters such the number of sensors, sensor placement, and sensor placement. We also introduced a robust data fusion and parameter estimation method based on Bayesian framework. Lastly, we described an initial work to construct a ground mobile sensor for indoor search and surveillance purposes.
Optimal template placement for searches of gravitational waves from precessing compact binary coalescences
Creators: name: Indik, Nathaniel
Publisher: name: Hannover : Institutionelles Repositorium der Leibniz Universität Hannover
Year: 2018
Subjects: subject: Gravitational waves
subject: Black holes
subject: Precession
subject: Template
subject: Gravitationswellen
subject: Schwarze Löcher
subject: Praezession
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: A new field of astronomy was opened up on Monday September 14th 2015, when the first detection of a Gravitational Wave was observed, GW150914. So far there have been no observations of gravitational waves produced from neutron-star--black-hole mergers. The observation of a neutron-star--black-hole merger would be significant because it would provide another way to study how compact binary coalescence gravitational wave signals relate to companion electromagnetic and neutrino emission signals. The difficulty in detecting precessing neutron-star--black-hole binaries (systems that allow for the full range of physical spin configurations) is that template banks for these precessing compact binary coalescence systems require many more templates than compact binary coalescence template banks that have been implemented previously. The purpose of the work presented in this thesis is to both improve the construction and efficiency of compact binary coalescence template banks. Template bank construction in the high dimensional precessing compact binary coalescence parameter spaces is complicated by the absence of a known analytic expression of mismatch inspiral-merger-ringdown metric. Previously, these restraints only permitted the use of the inefficient and slow to converge stochastic template placement algorithms. In this thesis, I constructed a template bank, the face-on-precessing template bank, over a subspace of this precessing neutron-star--black-hole template bank parameter space. I accomplished this by implementing a new algorithm for speeding up the convergence of the stochastic placement of these templates. I found that this subspace required 53 times more templates than the aligned-spin bank. Additionally, I developed an alternative template placement algorithm, the template nudging algorithm, to reposition compact binary coalescence templates into more effectual configurations in order to eliminate the effect of gridlines, artificially dense regions of the bank, that are characteristic of the hybrid template bank construction methods previously implemented in LIGO-Virgo compact binary coalescence searches. Finally, I developed a technique for constructing flat coordinates for compact binary coalescence template placements in high dimensional parameter spaces to ease in the construction of a fully precessing compact binary coalescence template bank.
Chirality Sensitive Domain Wall Motion in Spin-Orbit Coupled Ferromagnets
Creators: name: Linder, Jacob
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Using the Lagrangian formalism, we solve analytically the equations of motion for current-induced domain-wall dynamics in a ferromagnet with Rashba spin-orbit coupling. An exact solution for the domain wall velocity is provided, including the effect of non-equilibrium conduction electron spin-density, Gilbert damping, and the Rashba interaction parameter. We demonstrate explicitly that the influence of spin-orbit interaction can be qualitatively different from the role of non-adiabatic spin-torque in the sense that the former is sensitive to the chirality of the domain wall whereas the latter is not: the domain wall velocity shows a reentrant behavior upon changing the chirality of the domain wall. This could be used to experimentally distinguish between the spin-orbit and non-adiabatic contribution to the wall speed. A quantitative estimate for the attainable domain wall velocity is given, based on an experimentally relevant set of parameters for the system.
description: 7 pages, 2 figures. Accepted for publication in Phys. Rev. B
Federated Uncertainty-Aware Aggregation for Fundus Diabetic Retinopathy Staging
Creators: name: Wang, Meng
name: Wang, Lianyu
name: Xu, Xinxing
name: Zou, Ke
name: Qian, Yiming
name: Goh, Rick Siow Mong
name: Liu, Yong
name: Fu, Huazhu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Deep learning models have shown promising performance in the field of diabetic retinopathy (DR) staging. However, collaboratively training a DR staging model across multiple institutions remains a challenge due to non-iid data, client reliability, and confidence evaluation of the prediction. To address these issues, we propose a novel federated uncertainty-aware aggregation paradigm (FedUAA), which considers the reliability of each client and produces a confidence estimation for the DR staging. In our FedUAA, an aggregated encoder is shared by all clients for learning a global representation of fundus images, while a novel temperature-warmed uncertainty head (TWEU) is utilized for each client for local personalized staging criteria. Our TWEU employs an evidential deep layer to produce the uncertainty score with the DR staging results for client reliability evaluation. Furthermore, we developed a novel uncertainty-aware weighting module (UAW) to dynamically adjust the weights of model aggregation based on the uncertainty score distribution of each client. In our experiments, we collect five publicly available datasets from different institutions to conduct a dataset for federated DR staging to satisfy the real non-iid condition. The experimental results demonstrate that our FedUAA achieves better DR staging performance with higher reliability compared to other federated learning methods. Our proposed FedUAA paradigm effectively addresses the challenges of collaboratively training DR staging models across multiple institutions, and provides a robust and reliable solution for the deployment of DR diagnosis models in real-world clinical scenarios.
The Application of Driver Models in the Safety Assessment of Autonomous Vehicles: A Survey
Creators: name: Wang, Cheng
name: Guo, Fengwei
name: Yu, Ruilin
name: Wang, Luyao
name: Zhang, Yuxin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Driver models play a vital role in developing and verifying autonomous vehicles (AVs). Previously, they are mainly applied in traffic flow simulation to model driver behavior. With the development of AVs, driver models attract much attention again due to their potential contributions to AV safety assessment. The simulation-based testing method is an effective measure to accelerate AV testing due to its safe and efficient characteristics. Nonetheless, realistic driver models are prerequisites for valid simulation results. Additionally, an AV is assumed to be at least as safe as a careful and competent driver, which is modeled by driver models as well. Therefore, driver models are essential for AV safety assessment from the current perspective. However, no comparison or discussion of driver models is available regarding their utility to AVs in the last five years despite their necessities in the release of AVs. This motivates us to present a comprehensive survey of driver models in the paper and compare their applicability. Requirements for driver models as applied to AV safety assessment are discussed. A summary of driver models for simulation-based testing and AV benchmarks is provided. Evaluation metrics are defined to compare their strength and weakness. Finally, potential gaps in existing driver models are identified, which provide direction for future work. This study gives related researchers especially regulators an overview and helps them to define appropriate driver models for AVs.
Matrix Product Belief Propagation for reweighted stochastic dynamics over graphs
Creators: name: Crotti, Stefano
name: Braunstein, Alfredo
Publisher: name: arXiv
Year: 2023
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Social and Information Networks (cs.SI)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Biological sciences

description: Stochastic processes on graphs can describe a great variety of phenomena ranging from neural activity to epidemic spreading. While many existing methods can accurately describe typical realizations of such processes, computing properties of extremely rare events is a hard task. Particularly so in the case of recurrent models, in which variables may return to a previously visited state. Here, we build on the matrix product cavity method, extending it fundamentally in two directions: first, we show how it can be applied to Markov processes biased by arbitrary reweighting factors that concentrate most of the probability mass on rare events. Second, we introduce an efficient scheme to reduce the computational cost of a single node update from exponential to polynomial in the node degree. Two applications are considered: inference of infection probabilities from sparse observations within the SIRS epidemic model, and the computation of both typical observables and large deviations of several kinetic Ising models.
description: 22 pages, 7 figures, 1 table, appendix
Parallel Higher-order Boundary Integral Electrostatics Computation on Molecular Surfaces with Curved Triangulation
Creators: name: Geng, Weihua
Publisher: name: arXiv
Year: 2013
Subjects: subject: Numerical Analysis (math.NA)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: In this paper, we present a parallel higher-order boundary integral method to solve the linear Poisson-Boltzmann (PB) equation. In our method, a well-posed boundary integral formulation is used to ensure the fast convergence of Krylov subspace linear solver such as GMRES. The molecular surfaces are first discretized with flat triangles and then converted to curved triangles with the assistance of normal information at vertices. To maintain the desired accuracy, four-point Gauss-Radau quadratures are used on regular triangles and sixteen-point Gauss-Legendre quadratures together with regularization transformations are applied on singular triangles. To speed up our method, we take advantage of the embarrassingly parallel feature of boundary integral formulation, and parallelize the schemes with the message passing interface (MPI) implementation. Numerical tests show significantly improved accuracy and convergence of the proposed higher-order boundary integral Poisson-Boltzmann (HOBI-PB) solver compared with boundary integral PB solver using often-seen centroid collocation on flat triangles. The higher-order accuracy results achieved by present method are important to sensitive solvation analysis of biomolecules, particularly when accurate electrostatic surface potentials are critical in the molecular simulation. In addition, the higher-order boundary integral schemes presented here and their associated parallelization potentially can be applied to solving boundary integral equations in a general sense.
description: arXiv admin note: text overlap with arXiv:1301.5885
Parallel Seesaw Mechanisms for Neutrinos and Freeze-In Long-Lived Dark Matter
Creators: name: Ma, Ernest
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: If dark matter is light, it may be due to a seesaw mechanism just as neutrinos are. It is postulated that both originate from the same type of heavy fermion anchors, either singlets or triplets. In the latter case, a shift of the $W$ mass is predicted, as suggested by the $CDF$ precision measurement. A spontaneously broken dark $U(1)$ gauge symmetry is assumed, resulting in freeze-in long-lived light dark matter.
description: 11 pages, 1 figure, title changed in published version, major text revision
Explicit harmonic self-maps of complex projective spaces
Creators: name: Balado-Alves, José Miguel
Publisher: name: arXiv
Year: 2023
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 58E20, 53C43

description: We study $ { \mathrm{ SU } ( p + 1 ) \times \mathrm{ SU } ( n - p ) } $-equivariant maps between complex projective spaces. For every $ { n, p \in \mathbb{ N } } $ with $ { 0 \leq p < n } $, we construct two explicit families of uncountable many harmonic self-maps of $ \mathbb{ CP }^n $, one given by holomorphic maps and the other by maps that are neither holomorphic nor antiholomorphic. We prove that each solution is equivariantly weakly stable and explicitly compute the equivariant spectrum for some specific maps in both families.
description: 15 pages, 1 figure. v2: section 5 has been expanded
Charge transport through interfaces: a tight-binding toy model and its implications
Creators: name: Stickler, B. A.
name: Pötz, W.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: With the help of a tight-binding (TB) electronic-structure toy model we investigate the matching of parameters across hetero-interfaces . We demonstrate that the virtual crystal approximation, commonly employed for this purpose, may not respect underlying symmetries of the electronic structure. As an alternative approach we propose a method which is motivated by the matching of wave functions in continuous-space quantum mechanics. We show that this method obeys the required symmetries and can be applied in simple band to band transitions. Extension to multiple interfaces and to more sophisticated TB models is discussed.
Interferometric Upper Limits on Millimeter Polarization of the Disks around DG Tau, GM Aur, and MWC 480
Creators: name: Hughes, A. M.
name: Hull, C. L. H.
name: Wilner, D. J.
name: Plambeck, R. L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Millimeter-wavelength polarization measurements offer a promising method for probing the geometry of magnetic fields in circumstellar disks. Single dish observations and theoretical work have hinted that magnetic field geometries might be predominantly toroidal, and that disks should exhibit millimeter polarization fractions of 2-3%. While subsequent work has not confirmed these high polarization fractions, either the wavelength of observation or the target sources differed from the original observations. Here we present new polarimetric observations of three nearby circumstellar disks at 2" resolution with the Submillimeter Array (SMA) and the Combined Array for Research in Millimeter Astronomy (CARMA). We reobserve GM Aur and DG Tau, the systems in which millimeter polarization detections have been claimed. Despite higher resolution and sensitivity at wavelengths similar to the previous observations, the new observations do not show significant polarization. We also add observations of a new HAeBe system, MWC 480. These observations demonstrate that a very low (<0.5%) polarization fraction is probably common at large (>100 AU) scales in bright circumstellar disks. We suggest that high-resolution observations may be worthwhile to probe magnetic field structure on linear distances smaller than the disk scale height, as well as in regions closer to the star that may have larger MRI-induced magnetic field strengths.
description: 7 pages, 3 figures, accepted for publication in AJ
Entanglement of Harmonic Systems in Squeezed States
Creators: name: Katsinis, Dimitrios
name: Pastras, Georgios
name: Tetradis, Nikolaos
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The entanglement entropy of a free scalar field in its ground state is dominated by an area law term. It is noteworthy, however, that the study of entanglement in scalar field theory has not advanced far beyond the ground state. In this paper, we extend the study of entanglement of harmonic systems, which include free scalar field theory as a continuum limit, to the case of the most general Gaussian states, namely the squeezed states. We find the eigenstates and the spectrum of the reduced density matrix and we calculate the entanglement entropy. Finally, we apply our method to free scalar field theory in 1+1 dimensions and show that, for very squeezed states, the entanglement entropy is dominated by a volume term, unlike the ground-state case. Even though the state of the system is time-dependent in a non-trivial manner, this volume term is time-independent. We expect this behaviour to hold in higher dimensions as well, as it emerges in a large-squeezing expansion of the entanglement entropy for a general harmonic system.
description: 44 pages + 29 pages appendix, 13 figures. v2: version published in JHEP
Linear Precoding for Broadcast Channels with Confidential Messages under Transmit-Side Channel Correlation
Creators: name: Geraci, Giovanni
name: Al-nahari, Azzam Y.
name: Yuan, Jinhong
name: Collings, Iain B.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: In this paper, we analyze the performance of regularized channel inversion (RCI) precoding in multiple-input single-output (MISO) broadcast channels with confidential messages under transmit-side channel correlation. We derive a deterministic equivalent for the achievable per-user secrecy rate which is almost surely exact as the number of transmit antennas and the number of users grow to infinity in a fixed ratio, and we determine the optimal regularization parameter that maximizes the secrecy rate. Furthermore, we obtain deterministic equivalents for the secrecy rates achievable by: (i) zero forcing precoding and (ii) single user beamforming. The accuracy of our analysis is validated by simulations of finite-size systems.
description: to appear IEEE Communications Letters
Chiral chains with two valleys and disorder of finite correlation length
Creators: name: Touchais, Jean-Baptiste
name: Simon, Pascal
name: Mesaros, Andrej
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: In one-dimensional disordered systems with a chiral symmetry it is well-known that electrons at energy $E = 0$ avoid localization and simultaneously exhibit a diverging density of states (DOS). For $N$ coupled chains with zero-correlation-length disorder, the diverging DOS remains for odd $N$, but a vanishing DOS is found for even $N$. We use a thin spinless graphene nanotube with disordered Semenoff mass and disordered Haldane coupling to construct $N = 2$ chiral chain models which at low energy have two linear band crossings at different momenta $\pm K$ (two valleys) and disorder with an arbitrary correlation length $ξ$ in units of lattice constant $a$. We find that the finite momentum $\pm K$ forces the disorder in one valley to depend on the disorder in the other valley, thus departing from known analytical results which assume having $N$ independent disorders (whatever their spatial correlation lengths). Our main numerical results show that for this inter-dependent mass disorder the DOS is also suppressed in the limit of strongly coupled valleys (lattice-white noise limit, $ξ/a = 0$) and exhibits a non-trivial crossover as the valleys decouple ($ξ/a\gtrsim 5$) into the DOS shapes of the $N = 1$ continuum model with finite correlation length $ξ$. We also show that changing the intra-unit-cell geometry of the disordered Haldane coupling can tune the amount of inter-valley scattering yet at lowest energies it produces the decoupled-valley behavior ($N = 1$) all the way down to lattice white noise.
Phononenspektroskopie im Quanten-Hall-Effekt-Regime
Creators: name: Schulze Wischeler, Fritz
Publisher: name: Hannover : Technische Informationsbibliothek u. Universitätsbibliothek
Year: 2004
Subjects: subject: quantum Hall effect
subject: phonons
subject: composite fermion
subject: Quanten-Hall-Effekt
subject: Phononen
subject: Composite Fermion
subject: Quanten-Hall-Effekt
subject: Fraktionierter Quanten-Hall-Effekt
subject: Phonon
subject: Phononenspektroskopie
subject: Composite fermion
subject: Hochschulschrift
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: In dieser Arbeit wurde der Quanten-Hall-Effekt mit Hilfe von Phononen untersucht. Ziel der Arbeit war es, die thermodynamischen Eigenschaften von zweidimensionalen Elektronensystemen und Größe der Energielücken im fraktionalen Quanten-Hall-Effekt präzise zu vermessen. So gelang es, die Composite-Fermion-Masse und Landé g-Faktoren zu bestimmen. Darüberhinaus konnte die spezifische Wärme eines zweidimensionalen Elektronensystemens für diverse Füllfaktoren gemessen werden, einer thermodynamischen Größe, für die bisher keine experimentelle Technik zur Verfügung stand.
Optimization of CPMG sequences to measure NMR transverse relaxation time T2 in borehole applications
Creators: name: Ronczka, M.
name: Müller-Petke, M.
Publisher: name: Göttingen : Copernicus Publications
Year: 2012
Subjects: subject: Nuclear Magnetic Resonance
subject: Carr-Purcell-Meiboom-Gill sequence
subject: borehole application
subject: magnetische Kernresonanz
subject: Carr-Purcell-Meiboom-Gill-Sequenz
subject: Bohrlochanwendung
subject: 550

description: Nuclear Magnetic Resonance (NMR) can provide key information such as porosity and permeability for hydrological characterization of geological material. In particular the NMR transverse relaxation time T2 is used to estimate permeability since it reflects a pore-size dependent relaxation process. The measurement sequence (CPMG) usually consists of several thousands of electromagnetic pulses to densely record the relaxation process and to avoid relaxation processes that are due to diffusion. These pulses are equidistantly spaced by a time constant tE. In NMR borehole applications the use of CPMG sequences for measuring the transverse relaxation time T2 is limited due to requirements on energy consumption. For measuring T2, it is state-of-the-art to conduct at least two sequences with different echo spacings (tE) for recording fast and slow relaxing processes that correspond to different pore-sizes. We focus on conducting only a single CPMG sequence and reducing the amount of energy while obtaining both slow and fast decaying components and minimizing the influence of relaxation due to diffusion. Therefore, we tested the usage of CPMG sequences with an increasing tE and a decreasing number of pulses. A synthetic study as well as laboratory measurements on samples of glass beads and granulate material of different grain size spectra were conducted to evaluate the effects of an increasing tE. We show that T2 distributions are broadened if the number of pulses is decreasing and the mean grain size is increasing, which is mostly an effect of a significantly shortened acquisition time. The shift of T2 distributions to small decay times as a function of tE and the mean grain size distribution is observed. We found that it is possible to conduct CPMG sequences with an increased tE. According to the acquisition time and increasing influence of relaxation due to diffusion, the sequence parameters need to be chosen carefully to avoid misinterpretations.
A variational Monte Carlo algorithm for lattice gauge theories with continuous gauge groups: a study of (2+1)-dimensional compact QED with dynamical fermions at finite density
Creators: name: Bender, Julian
name: Emonts, Patrick
name: Cirac, J. Ignacio
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Lattice gauge theories coupled to fermionic matter account for many interesting phenomena in both high energy physics and condensed matter physics. Certain regimes, e.g. at finite fermion density, are difficult to simulate with traditional Monte Carlo algorithms due to the so-called sign-problem. We present a variational, sign-problem-free Monte Carlo method for lattice gauge theories with continuous gauge groups and apply it to (2+1)-dimensional compact QED with dynamical fermions at finite density. The variational ansatz is formulated in the full gauge field basis, i.e. without having to resort to truncation schemes for the $U(1)$ gauge field Hilbert space. The ansatz consists of two parts: first, a pure gauge part based on Jastrow-type ansatz states (which can be connected to certain neural-network ansatz states) and secondly, on a fermionic part based on gauge-field dependent fermionic Gaussian states. These are designed in such a way that the gauge field integral over all fermionic Gaussian states is gauge-invariant and at the same time still efficiently tractable. To ensure the validity of the method we benchmark the pure gauge part of the ansatz against another variational method and the full ansatz against an existing Monte Carlo simulation where the sign-problem is absent. Moreover, in limiting cases where the exact ground state is known we show that our ansatz is able to capture this behavior. Finally, we study a sign-problem affected regime by probing density-induced phase transitions.
description: 14+6 pages, 9+1 figures
title: Public Private Partnership (PPP): “Sustainability in the context of PPP Educational building Projects
Creators: name: Rajput, Renuka
Publisher: name: Technological University Dublin
Year: 2019

description: This PhD research focuses on and examines the relationship between PPP procurement and sustainability and further aims to establish whether PPP projects can be sustainable with regards to social, enviornmnetal and economic sustainability. The scope of the research is primarily confined to the implementation of construction related sustainability practices within PPPs. It introduces various PPP concepts and critiques the underlying principles for the utilisation of PPP in education sector. This discussion leads to the identification of the core factors common to Sustainability and PPPs and the challenges facing the public and private partners in implementing sustainability in its entirety. In turn, these challenges were analysed and it was found that they manifested themselves through one of the three core factors, namely: risk transfer, value for money & innovation and the disposition of these three factors towards partnership in a PPP environment.
Base Station Sleeping and Resource Allocation in Renewable Energy Powered Cellular Networks
Creators: name: Gong, Jie
name: Thompson, John S.
name: Zhou, Sheng
name: Niu, Zhisheng
Publisher: name: arXiv
Year: 2013
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We consider energy-efficient wireless resource management in cellular networks where BSs are equipped with energy harvesting devices, using statistical information for traffic intensity and harvested energy. The problem is formulated as adapting BSs' on-off states, active resource blocks (e.g. subcarriers) as well as power allocation to minimize the average grid power consumption in a given time period while satisfying the users' quality of service (blocking probability) requirements. It is transformed into an unconstrained optimization problem to minimize a weighted sum of grid power consumption and blocking probability. A two-stage dynamic programming (DP) algorithm is then proposed to solve this optimization problem, by which the BSs' on-off states are optimized in the first stage, and the active BS's resource blocks are allocated iteratively in the second stage. Compared with the optimal joint BSs' on-off states and active resource blocks allocation algorithm, the proposed algorithm greatly reduces the computational complexity, while at the same time achieves close to the optimal energy saving performance.
description: 30 pages, 10 figures, submitted to IEEE Transaction on Wireless Communications
Practical solutions for bottlenecks in ecosystem services mapping
Creators: name: Palomo, Ignacio
name: Willemen, Louise
name: Drakou, Evangelia
name: Burkhard, Benjamin
name: Crossman, Neville
name: Bellamy, Chloe
name: Burkhard, Kremena
name: Campagne, C. Sylvie
name: Dangol, Anuja
name: Franke, Jonas
name: Kulczyk, Sylwia
name: Le Clec'h, Solen
name: Malak, Dania Abdul
name: Munoz, Lorena
name: Narusevicius, Vytautas
name: Ottoy, Sam
name: Roelens, Jennifer
name: Sing, Louise
name: Thomas, Amy
name: Van Meerbeek, Koenraad
name: Verweij, Peter
Publisher: name: Sofia : Pensoft Publishers
Year: 2018
Subjects: subject: Ecosystem services
subject: mapping
subject: solutions
subject: spatial analysis
subject: sustainability
subject: Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften

description: Background: Ecosystem services (ES) mapping is becoming mainstream in many sustainability assessments, but its impact on real world decision-making is still limited. Robustness, end-user relevance and transparency have been identified as key attributes needed for effective ES mapping. However, these requirements are not always met due to multiple challenges, referred to here as bottlenecks, that scientists, practitioners, policy makers and users from other public and private sectors encounter along the mapping process. New information: A selection of commonly encountered ES mapping bottlenecks that relate to seven themes: i) map-maker map-user interaction; ii) nomenclature and ontologies; iii) skills and background; iv) data and maps availability; v) methods-selection; vi) technical difficulties; and vii) over-simplification of mapping process/output. The authors synthesise the variety of solutions already applied by map-makers and map-users to mitigate or cope with these bottlenecks and discuss the emerging trade-offs amongst different solutions. Tackling the bottlenecks described here is a crucial first step towards more effective ES mapping, which can in turn ensure the adequate impact of ES mapping in decision-making.
Impact of noise on the instability of spiral waves in stochastic 2D mathematical models of human atrial fibrillation
Creators: name: Song, Euijun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Tissues and Organs (q-bio.TO)
subject: FOS: Physical sciences
subject: FOS: Biological sciences
subject: 92C05, 92C30, 60H15

description: Sustained spiral waves, also known as rotors, are pivotal mechanisms in persistent atrial fibrillation (AF). Stochasticity is inevitable in nonlinear biological systems such as the heart; however, it is unclear how noise affects the instability of spiral waves in human AF. This study presents a stochastic two-dimensional mathematical model of human AF and explores how Gaussian white noise affects the instability of spiral waves. In homogeneous tissue models, Gaussian white noise may lead to spiral-wave meandering and wavefront break-up. As the noise intensity increases, the spatial dispersion of phase singularity (PS) points increases. This finding indicates the potential AF-protective effects of cardiac system stochasticity by destabilizing the rotors. By contrast, Gaussian white noise is unlikely to affect the spiral-wave instability in the presence of localized scar or fibrosis regions. The PS points are located at the boundary or inside the scar/fibrosis regions. Localized scar or fibrosis may play a pivotal role in stabilizing spiral waves regardless of the presence of noise. This study suggests that fibrosis and scars are essential for stabilizing the rotors in stochastic mathematical models of AF. Further patient-derived realistic modeling studies are required to confirm the role of scar/fibrosis in AF pathophysiology.
description: 8 pages, 8 figures, method and exposition improved
Phase diagram for K(1-x)(NH4)(x)H2PO4 (x = 0 – 0.15) solid solutions embedded into magnetic glasses
Creators: name: Vanina, P.Y.
name: Naberezhnov, A.A.
name: Sysoeva, A.A.
name: Nizhankovskii, V.I.
name: Nacke, B.
Publisher: name: Sankt Petersburg : St. Petersburg National Research University of Information Technologies, Mechanics and Optics
Year: 2017
Subjects: subject: ferroelectrics
subject: antiferroelectrics
subject: phase diagram
subject: nanocomposite materials
subject: magnetic porous glasses
subject: Dewey Decimal Classification::600 | Technik

description: Effect of magnetic field application on phase transition in nanostructured solid solutions (1-x)KH2PO4 – (x)(NH4)H2PO4 at x = 0, 0.05 and 0.15 has been studied by dielectric spectroscopy at B = 0 – 10T. The samples have been prepared by impregnation of magnetic porous glasses by KDP-ADP solid solutions. The average pore diameter in glasses was 50(5) nm. The temperatures of the ferroelectric phase transition have been determined, and the phase diagrams for these nanocomposite materials (NCM) on cooling and heating (including at magnetic field application) were constructed. The interface “matrix-nanoparticles” was shown to play the principal role in phase diagram formation.
Applying full polarization A-Projection to very wide field of view instruments: An imager for LOFAR
Creators: name: Tasse, C.
name: van der Tol, B.
name: van Zwieten, J.
name: van Diepen, Ger
name: Bhatnagar, S.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The aimed high sensitivities and large fields of view of the new generation of interferometers impose to reach high dynamic range of order $\sim$1:$10^6$ to 1:$10^8$ in the case of the Square Kilometer Array. The main problem is the calibration and correction of the Direction Dependent Effects (DDE) that can affect the electro-magnetic field (antenna beams, ionosphere, Faraday rotation, etc.). As shown earlier the A-Projection is a fast and accurate algorithm that can potentially correct for any given DDE in the imaging step. With its very wide field of view, low operating frequency ($\sim30-250$ MHz), long baselines, and complex station-dependent beam patterns, the Low Frequency Array (LOFAR) is certainly the most complex SKA precursor. In this paper we present a few implementations of A-Projection applied to LOFAR that can deal with non-unitary station beams and non-diagonal Mueller matrices. The algorithm is designed to correct for all the DDE, including individual antenna, projection of the dipoles on the sky, beam forming and ionospheric effects. We describe a few important algorithmic optimizations related to LOFAR's architecture allowing us to build a fast imager. Based on simulated datasets we show that A-Projection can give dramatic dynamic range improvement for both phased array beams and ionospheric effects. We will use this algorithm for the construction of the deepest extragalactic surveys, comprising hundreds of days of integration.
title: ÐÑÐ°Ð¼Ð¼Ð°ÑÐ¸ÐºÐ° Ð½ÐµÐ¼ÐµÑÐºÐ¾Ð³Ð¾ ÑÐ·ÑÐºÐ°. Ð£ÑÐ¾Ð²ÐµÐ½Ñ Ð1: Ð±Ð°Ð·Ð¾Ð²ÑÐ¹ ÐºÑÑÑ
title: ÑÑÐµÐ±Ð½Ð¾Ðµ Ð¿Ð¾ÑÐ¾Ð±Ð¸Ðµ
titleType: Subtitle
Creators: name: ÐÐ°ÑÐ°Ð»ÐºÐ¸Ð½Ð°, ÐÐ°ÑÐ°Ð»ÑÑ
name: ÐÐ¾Ð³Ð´Ð°Ð½Ð¾Ð²Ð°, ÐÐ°Ð´ÐµÐ¶Ð´Ð°
Publisher: name: ÐÐÐÐÐ¢ÐÐ¥-ÐÐ ÐÐ¡Ð¡
Year: 2024
Subjects: Ð½ÐµÐ¼ÐµÑÐºÐ¸Ð¹ ÑÐ·ÑÐº
Ð³ÑÐ°Ð¼Ð¼Ð°ÑÐ¸ÐºÐ°
ÑÑÐµÐ±Ð½Ð¸ÐºÐ¸ Ð¸ Ð¿Ð¾ÑÐ¾Ð±Ð¸Ñ Ð´Ð»Ñ Ð²ÑÐ·Ð¾Ð²

description: Ð£ÑÐµÐ±Ð½Ð¾Ðµ Ð¿Ð¾ÑÐ¾Ð±Ð¸Ðµ ÑÐ°ÑÐºÑÑÐ²Ð°ÐµÑ ÑÐ¾Ð´ÐµÑÐ¶Ð°Ð½Ð¸Ðµ ÑÑÐµÐ±Ð½Ð¾Ð¹ Ð´Ð¸ÑÑÐ¸Ð¿Ð»Ð¸Ð½Ñ Â«ÐÐµÐ¼ÐµÑÐºÐ¸Ð¹ ÑÐ·ÑÐº. ÐÐ°Ð·Ð¾Ð²ÑÐ¹ ÐºÑÑÑ (ÐÐ°ÑÑÐ±ÐµÐ¶Ð½Ð¾Ðµ ÑÐµÐ³Ð¸Ð¾Ð½Ð¾Ð²ÐµÐ´ÐµÐ½Ð¸Ðµ: ÐÐ±ÑÐ¸Ð¹ Ð¿ÑÐ¾ÑÐ¸Ð»Ñ)Â». Ð Ð´Ð°Ð½Ð½Ð¾Ðµ Ð¿Ð¾ÑÐ¾Ð±Ð¸Ðµ Ð²ÐºÐ»ÑÑÐµÐ½Ñ ÑÑÐµÐ±Ð½ÑÐµ Ð¼Ð°ÑÐµÑÐ¸Ð°Ð»Ñ Ð¿Ð¾ Ð²ÑÐµÐ¼ Ð¾ÑÐ½Ð¾Ð²Ð½ÑÐ¼ ÑÐµÐ¼Ð°Ð¼ ÐºÑÑÑÐ° Ð³ÑÐ°Ð¼Ð¼Ð°ÑÐ¸ÐºÐ¸ Ð½ÐµÐ¼ÐµÑÐºÐ¾Ð³Ð¾ ÑÐ·ÑÐºÐ°, ÑÐ²ÑÐ·Ð°Ð½Ð½ÑÐ¼ Ñ Ð±ÑÐ´ÑÑÐµÐ¹ Ð¿ÑÐ¾ÑÐµÑÑÐ¸Ð¾Ð½Ð°Ð»ÑÐ½Ð¾Ð¹ Ð´ÐµÑÑÐµÐ»ÑÐ½Ð¾ÑÑÑÑ ÑÑÑÐ´ÐµÐ½ÑÐ¾Ð². Ð£ÑÐµÐ±Ð½ÑÐµ Ð·Ð°Ð´Ð°Ð½Ð¸Ñ Ð¿Ð¾ ÑÐ°Ð·Ð²Ð¸ÑÐ¸Ñ Ð½Ð°Ð²ÑÐºÐ¾Ð² ÑÑÑÐ½Ð¾Ð¹ Ð¸ Ð¿Ð¸ÑÑÐ¼ÐµÐ½Ð½Ð¾Ð¹ ÑÐµÑÐ¸, Ð¿ÐµÑÐµÐ²Ð¾Ð´Ð° Ð³ÑÐ°Ð¼Ð¼Ð°ÑÐ¸ÑÐµÑÐºÐ¸Ñ ÐºÐ¾Ð½ÑÑÑÑÐºÑÐ¸Ð¹ Ñ Ð½ÐµÐ¼ÐµÑÐºÐ¾Ð³Ð¾ ÑÐ·ÑÐºÐ°, ÑÐ¾ÑÑÐ°Ð²Ð»ÐµÐ½Ð½ÑÐµ Ð½Ð° Ð¼Ð°ÑÐµÑÐ¸Ð°Ð»Ðµ Ð°Ð´Ð°Ð¿ÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð½ÑÑ ÑÐµÐºÑÑÐ¾Ð² Ð¼Ð¾Ð³ÑÑ ÑÐ»ÑÐ¶Ð¸ÑÑ ÐºÐ°Ðº Ð´Ð»Ñ Ð°ÑÐ´Ð¸ÑÐ¾ÑÐ½ÑÑ Ð·Ð°Ð½ÑÑÐ¸Ð¹, ÑÐ°Ðº Ð¸ Ð´Ð»Ñ ÑÐ°Ð¼Ð¾ÑÑÐ¾ÑÑÐµÐ»ÑÐ½Ð¾Ð¹ ÑÐ°Ð±Ð¾ÑÑ ÑÑÑÐ´ÐµÐ½ÑÐ¾Ð². ÐÐ¾ÑÐ¾Ð±Ð¸Ðµ Ð¿ÑÐµÐ´Ð½Ð°Ð·Ð½Ð°ÑÐµÐ½Ð¾ Ð´Ð»Ñ ÑÑÑÐ´ÐµÐ½ÑÐ¾Ð², Ð¾Ð±ÑÑÐ°ÑÑÐ¸ÑÑÑ Ð¿Ð¾ Ð½Ð°Ð¿ÑÐ°Ð²Ð»ÐµÐ½Ð¸Ñ (ÑÐ¿ÐµÑÐ¸Ð°Ð»ÑÐ½Ð¾ÑÑÐ¸) Ð¿Ð¾Ð´Ð³Ð¾ÑÐ¾Ð²ÐºÐ¸ Â«ÐÐ°ÑÑÐ±ÐµÐ¶Ð½Ð¾Ðµ ÑÐµÐ³Ð¸Ð¾Ð½Ð¾Ð²ÐµÐ´ÐµÐ½Ð¸Ðµ: ÐÐ±ÑÐ¸Ð¹ Ð¿ÑÐ¾ÑÐ¸Ð»ÑÂ» Ð² ÑÐ¾Ð¾ÑÐ²ÐµÑÑÑÐ²Ð¸Ð¸ Ñ Ð¾Ð±ÑÐµÐ¹ Ð¾Ð±ÑÐ°Ð·Ð¾Ð²Ð°ÑÐµÐ»ÑÐ½Ð¾Ð¹ Ð¿ÑÐ¾Ð³ÑÐ°Ð¼Ð¼Ð¾Ð¹ Â«ÐÐ²ÑÐ¾Ð¿ÐµÐ¹ÑÐºÐ¸Ðµ Ð¸ÑÑÐ»ÐµÐ´Ð¾Ð²Ð°Ð½Ð¸Ñ: ÐÐµÑÐ¼Ð°Ð½Ð¸ÑÂ».
Press Hardening of Tubes with Additional Interior Spray Cooling
Creators: name: Behrens, Bernd-Arno
name: Maier, H.J.
name: Neumann, A.
name: Moritz, J.
name: Hübner, S.
name: Gretzki, T.
name: Nürnberger, F.
name: Spiekermeier, A.
Publisher: name: Leibniz Universität Hannover
Year: 2015
Subjects: subject: 22MnB5
subject: hollow profiles
subject: press hardening
subject: tubes
subject: water-air spray cooling
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: Press-hardened profiles are used e.g. for automotive applications in order to improve light weight construction due to the high reachable strength. The application of interior water-air spray cooling contributes to significantly reducing the cycle time in the production of heat-treated tubes. This paper describes a new manufacturing method for producing press-hardened hollow profiles by means of an additional interior cooling based on a water-air spray. Furthermore, this paper provides the results of thorough investigations on the properties of press-hardened tubes in dependence of varying spray parameters.
Leading isospin breaking effects on the lattice
Creators: name: de Divitiis, G. M.
name: Frezzotti, R.
name: Lubicz, V.
name: Martinelli, G.
name: Petronzio, R.
name: Rossi, G. C.
name: Sanfilippo, F.
name: Simula, S.
name: Tantalo, N.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present a method to evaluate on the lattice the leading isospin breaking effects due to both the small mass difference between the up and down quarks and the QED interaction. Our proposal is applicable in principle to any QCD+QED gauge invariant hadronic observable which can be computed on the lattice. It is based on the expansion of the path-integral in powers of the small parameters (m_d - m_u)/Lambda_{QCD} and alpha_{em}, where m_f is the renormalized quark mass and alpha_{em} the renormalized fine structure constant. In this paper we discuss in detail the general strategy of the method and the conventional, although arbitrary, separation of QCD from QED isospin breaking corrections. We obtain results for the pion mass splitting, M_{pi+}^2-M_{pi0}^2= 1.44(13)(16) x 10^3 MeV^2, for the Dashen's theorem breaking parameter epsilon_{gamma}= 0.79(18)(18), for the light quark masses, [m_d - m_u](MSbar,2 GeV)= 2.39(8)(17) MeV, [m_u / m_d](MSbar,2 GeV)= 0.50(2)(3) and for the flavour symmetry breaking parameters R and Q. We also update our previous results for the QCD isospin breaking corrections to the Kl2 decay rate and for the QCD contribution to the neutron-proton mass splitting.
description: 39 pages, 17 figures
Quartic solitons of a mode-locked laser distributed model
Creators: name: Malheiro, D.
name: Facão, M.
name: Carvalho, M. I.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Dissipative quartic solitons have gained interest in the field of mode-locked lasers for their energy-width scaling which allows the generation of ultrashort pulses with high energies. Pursuing the characterization of such pulses, here we found soliton solutions of a distributed model for mode-locked lasers in the presence of either positive or negative fourth order dispersion (4OD). We studied the impact the laser parameters may have on the profiles, range of existence and energy-width relation of the output pulses. The most energetic and narrowest solutions occur for negative 4OD, with the energy having an inverse cubic dependence with the width in most cases. Our simulations showed that the spectral filtering has the biggest contribution in the generation of short (widhts as low as 39 fs) and very energetic (392 nJ) optical pulses.
Network Observability Transitions
Creators: name: Yang, Yang
name: Wang, Jianhui
name: Motter, Adilson E.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: In the modeling, monitoring, and control of complex networks, a fundamental problem concerns the comprehensive determination of the state of the system from limited measurements. Using power grids as example networks, we show that this problem leads to a new type of percolation transition, here termed a {\it network observability transition}, which we solve analytically for the configuration model. We also demonstrate a dual role of the network's community structure, which both facilitates optimal measurement placement and renders the networks substantially more sensitive to `observability attacks'. Aside from their immediate implications for the development of smart grids, these results provide insights into decentralized biological, social, and technological networks.
Parameterized complexity of decision problems in non-classical logics
Creators: name: Schindler, Irena
Publisher: name: Hannover : Institutionelles Repositorium der Leibniz Universität Hannover
Year: 2018
Subjects: subject: default logic
subject: temporal logic
subject: backdoor
subject: Post’s Lattice
subject: tree- and pathwidth
subject: temporal depth
subject: Parameterized complexity
subject: Default Logik
subject: Temporale Logik
subject: Baum- und Pfadweite
subject: temporale Tiefe
subject: Parametrisierte Komplexität
subject: Dewey Decimal Classification::000 | Allgemeines, Wissenschaft::000 | Informatik, Wissen, Systeme::004 | Informatik

description: Parameterized complexity is a branch of a computational complexity. The pioneers of this new and promising research field are Downey and Fellows. They suggest to examine the structural properties of a given problem and restrict the instance by a parameter. In this thesis we investigate the parameterized complexity of various problems in default logic and in temporal logics. In the first section of Chapter 3 we introduce a dynamic programming algorithm which decides whether a given default theory has a consistent stable extension in fpt-time and enumerates all generating defaults that lead to a stable extension with a pre-computation step that is linear in the input theory and triple exponential in the tree-width followed by a linear delay to output solutions. In the second part of this chapter we lift the notion of backdoors to the field of default logics. We consider two problems, first we are interested to detect a backdoor and then to evaluate it for the target formulae classes HORN, KROM, POSITIVE-UNITand MONOTONE. In Chapter 4, we investigate the parameterized complexity of problems in various tem- poral logics. In the first section we introduce several graph-like structures for formula representation and the corresponding notion of tree-width and path-width. To obtain the fixed parameter tractability of different fragments, we generalize the prominent Courcelle’s Theorem to work for infinite signatures. In this section, we also consider Boolean operator fragments in the sense of Post’s lattice. In the second part of Chapter 4 we introduce the notion of backdoors for the glob- ally fragment of linear temporal logic. Again, our problems of interest are to detect a backdoor and to evaluate it, this time, for the target formulae classes HORN and KROM.