Miracle-dz/UniFAR-FTUs huggingface dataset:
Mathematical Modeling and System Identification Aspects of Heat Flow Process inside a Closed Box

This paper presents review points of mathematical modeling and system identification issues of heat flow process inside a closed box. For system parameter identification, the least squares method is employed and NI Temperature Box is used as a test rig for different reference temperature values. Curve Fitting toolbox and M-file codes written in MATLAB are used based on the Levenberg-Marquardt algorithm in solving least squares equations of the system.
Search for 2β decay of cerium isotopes with CeCl3 scintillator

Double beta processes in 136Ce, 138Ce and 142Ce have been searched for by exploiting the active source approach with the help of a 6.9 g CeCl3 crystal as a scintillator for the first time at the Gran Sasso National Laboratory (LNGS) of the INFN (Italy). The total measurement time is 1638 h; even such a small exposure has allowed the achievement of some improved half-life limits on 2β decay processes in these isotopes at the level of 1016–1018 yr. In particular (90% C.L.): T0νeβ+1/2(136Ce) ≥ 8.8 × 1016 yr, T2νeβ+1/2(136Ce) ≥2.4 × 1016 yr, T2ν2K1/2(136Ce) ≥3.2 × 1016 yr, T2ν2K1/2(138Ce) ≥4.4 × 1016 yr, and T2ν2β−1/2(142Ce) ≥1.4 × 1018 yr. Possible future perspectives are also briefly addressed.
Feedback positioning cantilever using lead zirconate titanate thin film for force microscopy observation of micropattern

An atomic force microscope cantilever with PZT thin film with pyramidal stylus was used for actuation of feedback motion. The maximum stroke of the cantilever was more than 1 μm within a frequency range from direct current up to natural resonant frequency, e.g., 28.48 kHz. An image of a pit of a compact disk with a depth of 100 nm was successfully obtained using only cantilever actuation in a vertical direction.
Operator Reproducing Kernel Hilbert Spaces

Motivated by the need of processing functional-valued data, or more general, operatorvalued data, we introduce the notion of the operator reproducing kernel Hilbert space (ORKHS). This space admits a unique operator reproducing kernel which reproduces a family of continuous linear operators on the space. The theory of ORKHSs and the associated operator reproducing kernels are established. A special class of ORKHSs, known as the perfect ORKHSs, are studied, which reproduce the family of the standard point-evaluation operators and at the same time another different family of continuous linear operators. The perfect ORKHSs are characterized in terms of features, especially for those with respect to integral operators. In particular, several specific examples of the perfect ORKHSs are presented. We apply the theory of ORKHSs to sampling and regularized learning, where operator-valued data are considered. Specifically, a general complete reconstruction formula from linear operators values is established in the framework of ORKHSs. The average sampling and the reconstruction of vector-valued functions are considered in specific ORKHSs. We also investigate in the ORKHSs setting the regularized learning schemes, which learn a target element from operator-valued data. The desired representer theorems of the learning problems are established to demonstrate the key roles played by the ORKHSs and the operator reproducing kernels in machine learning from operator-valued data. We finally point out that the continuity of linear operators, used to obtain the operator-valued data, on an ORKHS is necessary for the stability of the numerical reconstruction algorithm using the resulting data.
Funk and Hilbert geometries from the Finslerian Viewpoint

In 1929, Paul Funk and Ludwig Berwald gave a characterization of Hilbert geometries from the Finslerian viewpoint. They showed that a smooth Finsler metric in a convex bounded domain of $\mathbb{R}^n$ is the Hilbert geometry in that domain if and only if it is complete, if its geodesics are straight lines and if its flag curvature is equal to -1. The goal of this chapter is to explain these notions in details, to illustrate the relation between Hilbert geometry, Finsler geometry and the calculus of variations, and to prove the Funk-Berwald characterization Theorem.
Effects of dc electric field on mechanical properties of piezoelectric ceramics

The effects of dc electric field on mechanical properties such as hardness, fracture toughness, flexural strength and flexural fatigue strength of piezoelectric ceramics were investigated. Hardness and fracture toughness were not influenced by the dc electric field, where as the flexural strength and the fatigue strength degraded with the absolute value of the electric field. The degradation of the flexural strength and the acceleration of fatigue were greater under an electric field whose direction was opposite to the poling direction than an electric field whose direction was the same as the poling direction. The main cause of strength degradation and fatigue acceleration in piezoelectric ceramics is estimated to be the microscopic internal stress which is generated at the grain boundary by the piezoelectric and domain switching deformations.
Search for OB stars running away from young star clusters - I. NGC 6611

N-body simulations have shown that the dynamical decay of the young (∼1 Myr) Orion Nebula cluster could be responsible for the loss of at least half of its initial content of OB stars. This result suggests that other young stellar systems could also lose a significant fraction of their massive stars at the very beginning of their evolution. To confirm this expectation, we used the Mid-Infrared Galactic Plane Survey (completed by the Midcourse Space Experiment satellite) to search for bow shocks around a number of young (<several Myr) clusters and OB associations. We discovered dozens of bow shocks generated by OB stars running away from these stellar systems, supporting the idea of significant dynamical loss of OB stars. In this paper, we report the discovery of three bow shocks produced by O-type stars ejected from the open cluster NGC 6611 (M16). One of the bow shocks is associated with the O9.5Iab star HD165319, which was suggested to be one of “the best examples for isolated Galactic high-mass star formation” (de Wit et al. 2005, A&A, 437, 247). Possible implications of our results for the origin of field OB stars are discussed.
Monoidal uniqueness theorems for stable homotopy theory

We show that the monoidal product on the stable homotopy category of spectra is essentially unique. This strengthens work of this author with Schwede on the uniqueness of models of the stable homotopy theory of spectra. As an application we show that with an added assumption about underlying model structures Margolis' axioms uniquely determine the stable homotopy category of spectra up to monoidal equivalence. Also, the equivalences constructed here give a unified construction of the known equivalences of the various symmetric monoidal categories of spectra (S-modules, \W-spaces, orthogonal spectra, simplicial functors) with symmetric spectra. The equivalences of modules, algebras and commutative algebras in these categories are also considered.
Blind identification of polynomial matrix fraction via independent component analysis

This paper proposes a method for blind system identification based on independence of input signals. Under the assumption that the system is multi‐input multi‐output, square, and represented by a polynomial matrix fraction with constant numerator matrix, the method makes it possible to identify the system parameter without observation of input signals. This rather challenging problem is solved by applying independent component analysis to an augmented state‐space representation in order to estimate coefficients of the denominator polynomial matrix and the numerator matrix. After giving this blind system identification algorithm, the paper shows how the proposed method is used in application. The first issue is suppression of disturbance with unknown dynamics. Assuming that a disturbance enters into a system independently of the control input signals, the method identifies a denominator polynomial matrix of the disturbance dynamics. Then an H∞ controller is designed in order to suppress the effect of the disturbance. The second is fault detection of mechanical systems subject to vibration from the environment. The vibration source is assumed to be unmeasurable, and yet the method achieves detection of a parameter change of the system due to fault. Copyright © 2006 John Wiley & Sons, Ltd.
Apparent criticality and calibration issues in the Hawkes self-excited point process model: application to high-frequency financial data

We present a careful analysis of possible issues on the application of the self-excited Hawkes process to high-frequency financial data. We analyse a set of effects leading to significant biases in the estimation of the ‘criticality index’ n that quantifies the degree of endogeneity of how much past events trigger future events. We report the following model biases: (i) evidence of strong upward biases on the estimation of n when using power law memory kernels in the presence of outliers, (ii) strong effects on n resulting from the form of the regularization part of the power law kernel, (iii) strong edge effects on the estimated n when using power law kernels and (iv) the need for an exhaustive search of the absolute maximum of the log-likelihood function due to its complicated shape. Moreover, we demonstrate that the calibration of the Hawkes process on mixtures of pure Poisson process with changes of regime leads to completely spurious apparent critical values for the branching ratio (), while the true value is actually . More generally, regime shifts on the parameters of the Hawkes model and/or on the generating process itself are shown to systematically lead to a significant upward bias in the estimation of the branching ratio. We demonstrate the importance of the preparation of the high-frequency financial data, in particular: (a) the impact of overnight trading in the analysis of long-term trends, (b) intraday seasonality and detrending of the data and (c) vulnerability of the analysis to day-to-day non-stationarity and regime shifts. Special care is given to the decrease of quality of the timestamps of tick data due to latency and grouping of messages to packets by the stock exchange. Altogether, our careful exploration of the caveats of the calibration of the Hawkes process stresses the need for considering all the above issues before any conclusion can be sustained. In this respect, because the above effects are plaguing their analyses, the claim by Hardiman et al. [Eur. Phys. J. B – Cond. Matter Comp. Syst. , 2013, 86, 442] that financial market has been continuously functioning at or close to criticality () cannot be supported. In contrast, our previous results on E-mini S&P 500 Futures Contracts and on major commodity future contracts are upheld.
A young double stellar cluster in a HII region, emerging from its parent molecular cloud

We report the properties of a new young double stellar cluster in the region towards IRAS 07141-0920 contained in the HII region Sh2-294. High-resolution optical UBVRI and Halpha images, near-infrared JHKs and H2 filter images were used to make photometric and morphological studies of the point sources and the nebula seen towards Sh2-294. The optical images reveal an emission nebula with very rich morphological details, composed mainly of UV scattered light and of Halpha emission. Contrasting with the bright parts of the nebula, opaque, elongated patches are seen. Our optical photometry confirms that the illuminator of the nebula is likely to be a B0.5V star located at a distance of about 3.2 kpc. Our near-IR images reveal an embedded cluster, extending for about 2 pc and exhibiting sub-clustering: a denser, more condensed, sub-cluster surrounding the optical high-mass B0.5V illuminator star; and a more embedded, optically invisible, sub-cluster located towards the eastern, dark part of the nebula and including the luminous MSX source G224.1880+01.2407, a massive protostellar candidate that could be the origin of jets and extended features seen at 2.12 micron. The double cluster appears to be clearing the remaining molecular material of the parent cloud, creating patches of lower extinction and allowing some of the least reddened members to be detected in the optical images. We find 12 MS and 143 PMS members using 3 different methods: comparison with isochrones in optical colour-magnitude diagrams, detection of near-IR excess, and presence of Halpha emission. The most massive star fits a 4 Myr post-MS isochrone. The age of the optically selected PMS population is estimated to be 7-8 Myr. The IR-excess population shows sub-clustering on scales as small as 0.23 pc and is probably much younger.
Implementing the Point Spread Function Deconvolution for Better Molecular Characterization of Newly Diagnosed Gliomas: A Dynamic 18F-FDOPA PET Radiomics Study

Simple Summary The point spread function deconvolution (PSFd), which is known to improve contrast and spatial resolution of brain positron emission tomography (PET) images, has not been evaluated for the routine analysis of amino-acid PET imaging. Our study therefore investigated the effects of applying the PSFd to a radiomics analysis of the clinical dynamic L-3,4-dihydroxy-6-[18F]-fluoro-phenyl-alanine (18F-FDOPA) PET images (tumor-to-background ratio and time-to-peak parametric images), and evaluated the impact of these effects on the molecular characterization of newly diagnosed gliomas. We show that applying the PSFd to dynamic 18F-FDOPA PET images significantly improves the detection of molecular parameters in newly diagnosed gliomas for predicting isocitrate dehydrogenase mutated and/or 1p/19q codeleted gliomas, for a combination of radiomics features extracted from static and dynamic parametric images. Abstract Purpose: This study aims to investigate the effects of applying the point spread function deconvolution (PSFd) to the radiomics analysis of dynamic L-3,4-dihydroxy-6-[18F]-fluoro-phenyl-alanine (18F-FDOPA) positron emission tomography (PET) images, to non-invasively identify isocitrate dehydrogenase (IDH) mutated and/or 1p/19q codeleted gliomas. Methods: Fifty-seven newly diagnosed glioma patients underwent dynamic 18F-FDOPA imaging on the same digital PET system. All images were reconstructed with and without PSFd. An L1-penalized (Lasso) logistic regression model, with 5-fold cross-validation and 20 repetitions, was trained with radiomics features extracted from the static tumor-to-background-ratio (TBR) and dynamic time-to-peak (TTP) parametric images, as well as a combination of both. Feature importance was assessed using Shapley additive explanation values. Results: The PSFd significantly modified 95% of TBR, but only 79% of TTP radiomics features. Applying the PSFd significantly improved the ability to identify IDH-mutated and/or 1p/19q codeleted gliomas, compared to PET images not processed with PSFd, with respective areas under the curve of 0.83 versus 0.79 and 0.75 versus 0.68 for a combination of static and dynamic radiomics features (p < 0.001). Without the PSFd, four and eight radiomics features contributed to 50% of the model for detecting IDH-mutated and/or 1p/19q codeleted gliomas, respectively. Application of the PSFd reduced this to three and seven contributive radiomics features. Conclusion: Application of the PSFd to dynamic 18F-FDOPA PET imaging significantly improves the detection of molecular parameters in newly diagnosed gliomas, most notably by modifying TBR radiomics features.
Reconstruction of the temporal component in the source term of a (time-fractional) diffusion equation

In this article, we consider the reconstruction of ρ(t) in the (time-fractional) diffusion equation (∂tα−△)u(x,t)=ρ(t)g(x) (0<α⩽1) by observation at a single point x0. We are mainly concerned with the situation of x0∉suppg, which is practically important but has not been well investigated in literature. Assuming finite sign changes of ρ and an extra observation interval, we establish the multiple logarithmic stability for the problem based on a reverse convolution inequality and a lower estimate for positive solutions. Meanwhile, we develop a fixed-point iteration for the numerical reconstruction and prove its convergence. The performance of the proposed method is illustrated by several numerical examples.
Crowd Counting and Localization Beyond Density Map

Crowd analysis in general and counting in congested scenes, in particular, is an effective and vibrant research domain in computer vision due to its numerous applications. Understanding the risk analysis and safety aspects of crowd dynamics at various vital occasions related to sports cultural and religious activities, specifically, at Hajj and Umrah, is essential. Thousands of people gathered in a small area to carry out their rites. Localizing and counting the annotated head points is quite challenging due to occlusion and large-scale variation in the congested environment. To deal with these problems, a small and effective solution is to generate the density maps. However, the significant flaws of the density map have a blurry Gaussian blob which is less effective for counting and localizing head annotations in the congested scene. To overcome these issues, we propose Congested Scene Crowd Counting and Localization Network (CSCCL-Net) with a Focal inverse Distance Transform (FIDT) map that can count and localize the people simultaneously in the highly congested scene. To evaluate the proposed model’s efficiency, extensive tests were performed on the ShanghaiTech part A, ShanghaiTech part B, and JHU-CROWD++ datasets. The proposed model outperforms existing state-of-the-art techniques regarding high accuracy and low Mean Absolute Error (MAE) and Mean Square Error (MSE) values.
Generalized Thermal J‐V Characteristic for the Electric Tunnel Effect

The thermal J‐V characteristic for a tunnel junction is derived in terms of a generalized theory. The resulting functional form of the equations is similar to that of Stratton; however, in the present formulation, the physical parameters of the junction appear explicitly, and their effect upon the thermal characteristic is readily appreciated. In Stratton's work, the physical constants appear in the integrand of integral that can be solved only numerically.The theory is applied to symmetric and asymmetric junctions. For the symmetric case, it is shown that, at a given temperature, the percentage change Ĵ in the high‐temperature thermal component of current from the low‐temperature value increases initially with increasing voltage bias up to a maximum peak, and thereafter decreases rapidly. The voltage bias at which the component of thermal current maxima occurs is equal to the interfacial barrier height and, as such, permits what is probably the most accurate method of barrier height determination. Simila.
Computing Quasiconformal Maps on Riemann surfaces using Discrete Curvature Flow

Surface mapping plays an important role in geometric processing. They induce both area and angular distortions. If the angular distortion is bounded, the mapping is called a {\it quasi-conformal} map. Many surface maps in our physical world are quasi-conformal. The angular distortion of a quasi-conformal map can be represented by Beltrami differentials. According to quasi-conformal Teichm\"uller theory, there is an 1-1 correspondence between the set of Beltrami differentials and the set of quasi-conformal surface maps. Therefore, every quasi-conformal surface map can be fully determined by the Beltrami differential and can be reconstructed by solving the so-called Beltrami equation. In this work, we propose an effective method to solve the Beltrami equation on general Riemann surfaces. The solution is a quasi-conformal map associated with the prescribed Beltrami differential. We firstly formulate a discrete analog of quasi-conformal maps on triangular meshes. Then, we propose an algorithm to compute discrete quasi-conformal maps. The main strategy is to define a discrete auxiliary metric of the source surface, such that the original quasi-conformal map becomes conformal under the newly defined discrete metric. The associated map can then be obtained by using the discrete Yamabe flow method. Numerically, the discrete quasi-conformal map converges to the continuous real solution as the mesh size approaches to 0. We tested our algorithm on surfaces scanned from real life with different topologies. Experimental results demonstrate the generality and accuracy of our auxiliary metric method.
Stable processes, self-similarity and the unit ball

Around the 1960s a celebrated collection of papers emerged offering a number of explicit identities for the class of isotropic stable processes in one and higher dimensions; these include, for example, the lauded works of Blumenthal, Getoor, Ray, Port and Rogozin. Amongst other things, these results nicely exemplify the use of standard Riesz potential theory on the unit open ball $\mathbb{B}_d :=\{ x\in \mathbb{R}^d :|x|<1\}$, $\mathbb{R}^d\backslash\mathbb{B}_d$ and $\mathbb{S}_d :=\partial \mathbb{B}_d$ with the, then, modern theory of potential analysis for Markov processes. Following initial observations of Lamperti in 1972, with the occasional sporadic work of Kiu, Vuolle-Apiala and Graversen in the 1980s, an alternative understanding of stable processes through the theory of self-similar Markov processes has prevailed in the last decade or more. This point of view offers deeper probabilistic insights into some of the aforementioned potential analytical relations. In this review article, we will rediscover many of the aforementioned classical identities in relation to the unit ball and recent extensions thereof by combining elements of these two theories, which have otherwise been largely separated by decades in the literature. We present a dialogue that appeals as much as possible to path decompositions. Most notable in this respect is the Lamperti-Kiu decomposition of self-similar Markov processes and the Riesz-Bogdan-\. Zak transformation. Some of the proofs we give are known, some are known proofs mixed with new methods and some proofs are completely new. We assume that the reader has a degree of familiarity with the bare basics of L\'evy processes but nonetheless, we often include reminders of standard material.
The classical-quantum boundary for correlations: Discord and related measures

One of the best signatures of nonclassicality in a quantum system is the existence of correlations that have no classical counterpart. Different methods for quantifying the quantum and classical parts of correlations are amongst the more actively-studied topics of quantum information theory over the past decade. Entanglement is the most prominent of these correlations, but in many cases unentangled states exhibit nonclassical behavior too. Thus distinguishing quantum correlations other than entanglement provides a better division between the quantum and classical worlds, especially when considering mixed states. Here we review different notions of classical and quantum correlations quantified by quantum discord and other related measures. In the first half, we review the mathematical properties of the measures of quantum correlations, relate them to each other, and discuss the classical-quantum division that is common among them. In the second half, we show that the measures identify and quantify the deviation from classicality in various quantum-information-processing tasks, quantum thermodynamics, open-system dynamics, and many-body physics. We show that in many cases quantum correlations indicate an advantage of quantum methods over classical ones.
Time evolution and adiabatic approximation in PT-symmetric quantum mechanics

In this paper, we discuss time evolution and adiabatic approximation in PT-symmetric quantummechanics. we give the time evolving equation for a class of PT-symmetric Hamiltonians and someconditions of the adiabatic approximation for the class of PT-symmetric Hamiltonians.DOI: PACS numbers: 03.67. Mn, 03.65. Ud