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Indoor Positioning by CSI Amplitude and Neural Networks

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Indoor Positioning by CSI Amplitude and Neural Networks

Digital Signal Processing and its Applications (DSPA), International Conference on

作者： Alexandr Astafiev Olesya Astafieva Ilya Kondrushin Dept. of Physics and Applied Math. Vladimir State University Murom Russia Faculty of IT and Radio Electronics Vladimir State University Murom Russia

Requirements for positioning accuracy indoors are constantly increasing. However, there is no single solution for organizing such positioning, and each individual project uses its own practical implementations. The paper uses channel state information at the physical layer to determine the distance between radio devices. In particular, the amplitude of the signal over 56 subcarriers is used. The task of determining the distance is positioned as a classification task. To solve it, a neural network with fully connected hidden layers is used. To train the neural network, an experiment was conducted to collect information in a technical laboratory measuring ${5.5\mathrm{x}4}$ meters. The resulting dataset is divided into a training set, a validation set, and a test set. The results of the experiments showed the accuracy in determining the distance between radio devices in the range of 99.47 – 99.75% on the training set. While on the test sample, the accuracy was 96.2 – 98.8%. The distances obtained as a result of the proposed algorithm can be used for indoor positioning using the trilateration method.

关键词： Training Meters Neural networks Signal processing algorithms Digital signal processing Physical layer Classification algorithms

Investigating of structural, electronic, magnetic, dynamic, and thermoelectric properties of CoCrSe half-Heusler compound using FP-LAPW method

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The European Physical Journal B 2024年第5期97卷 1-14页

作者： AlShaikh Mohammad, Noorhan F. Abu-Jafar, Mohammed S. Asad, Jihad H. Bouhemadou, A. Mousa, Ahmad A. Khenata, R. Chik, Abdullah Department of Physics An-Najah National University Nablus Palestine Department of Physics Faculty of Applied Sciences Palestine Technical University Tulkarm Palestine Laboratory for Developing New Materials and their Characterizations Department of Physics Faculty of Science Ferhat Abbas University - Setif 1 Setif Algeria Middle East University Amman Jordan Applied Science Research Center Applied Science Private University Amman Jordan Laboratoire de Physique Quantique et de Modélisation Mathématique de la Matière (LPQ3M) Université de Mascara Mascara Algeria Faculty of Chemical Engineering and Technology Universiti Malaysia Perlis (UniMAP) Arau Malaysia

The structural, elastic, electronic, magnetic, thermoelectric, and dynamic properties of the $$CoCrSe$$ half-Heusler compound were examined using the WIEN2k code. Calculations were carried out in this work using the full-potential linearized augmented plane-wave (FP-LAPW) approach and density functional theory (DFT). We used modified Becke–Johnson (mBJ) exchange–correlation functional to improve the electronic energy bandgap. We studied different electronic properties of the $$CoCrSe$$ compound, including density of states (DOS) and band structure plots. We also investigated the magnetic characteristics by computing magnetic moments and examining the behavior of spin-polarized electronic states. In addition, the elastic characteristics of the $$CoCrSe$$ compound were determined. These properties, such as stiffness, resilience, and general stability, provide vital insights into the material’s response to mechanical deformation. The calculated elastic constants indicate that $$CoCrSe$$ it is mechanically stable, brittle, and anisotropic. On the other hand, the compound is dynamically stable. Finally, we also check the thermoelectric properties.

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Formalization of basic combinatorics on words 12

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Formalization of basic combinatorics on words

12th International Conference on Interactive Theorem Proving, ITP 2021

作者： Holub, Štěpán Starosta, Štěpán Department of Algebra Faculty of Mathematics and Physics Charles University Prague Czech Republic Dept. of Applied Math. Faculty of Information Technology Czech Technical University Prague Czech Republic

ISBN: (纸本)9783959771887

Combinatorics on Words is a rather young domain encompassing the study of words and formal languages. An archetypal example of a task in Combinatorics on Words is to solve the equation x · y = y · x, i.e., to describe words that commute. This contribution contains formalization of three important classical results in Isabelle/HOL. Namely i) the Periodicity Lemma (a.k.a. the theorem of Fine and Wilf), including a construction of a word proving its optimality;ii) the solution of the equation xa · yb = zc with 2 ≤ a, b, c, known as the Lyndon-Schützenberger Equation;and iii) the Graph Lemma, which yields a generic upper bound on the rank of a solution of a system of equations. The formalization of those results is based on an evolving toolkit of several hundred auxiliary results which provide for smooth reasoning within more complex tasks. © Štěpán Holub and Štěpán Starosta.

关键词： Formal languages

Radial kinks in a Schwarzschild-like geometry

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Physical Review D 2024年第12期110卷 125025-125025页

作者： Jean-Guy Caputo Tomasz Dobrowolski Jacek Gatlik Panayotis G. Kevrekidis Laboratoire de Mathématiques INSA de Rouen Avenue de l’Université 76801 Saint-Etienne du Rouvray France Department of Computer Physics and Quantum Computing University of the National Education Commission in Krakow Podchora¸żych 2 30-084 Cracow Poland AGH University of Krakow Faculty of Physics and Applied Computer Science 30-059 Krakow Poland Department of Mathematics and Statistics University of Massachusetts Amherst Massachusetts 01003-4515 USA

We study the propagation of a domain wall (kink) of the ϕ4 model in a radially symmetric environment defined by a gravity source. This source introduces a Schwarzschild-like geometry. We introduce an effective model that accurately describes the dynamics of the kink center. This description works well even outside the perturbation region, i.e., even for large masses of the gravitating object. We observed that such a spherical domain wall surrounding a star-type object inevitably “collapses,” i.e., shrinks in radius toward the origin and offer an understanding of the latter phenomenology. The relevant analysis is presented for a circular domain wall and a spherical one.

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Synthesis of iron-doped zinc oxide (Fe-ZnO) nanoparticles by using several stabilizers 1

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Synthesis of iron-doped zinc oxide (Fe-ZnO) nanoparticles by...

1st South East Asia Science, Technology, Engineering and mathematics International Conference, SEA- STEM 2020

作者： Muktaridha, O. Adlim, M. Suhendrayatna, S. Ismail, I. Graduate School of Mathematics and Applied Science Universitas Syiah Kuala Darussalam Banda Aceh23111 Indonesia Chemical Engineering Department Faculty of Engineering Universitas Syiah Kuala Darussalam Banda Aceh23111 Indonesia Physics Department Faculty of Math and Natural Science Universitas Syiah Kuala Darussalam Banda Aceh23111 Indonesia

Studies on the effect of the stabilizer of chitosan, citric acid and urea for preparation Fe-doped ZnO have been conducted. Both ZnO and Fe were prepared from each salt precursor solution. The Zn2+ was added fist and subsequently Fe2+ by dropwise method into each stabilizer solution before converted into the hydroxide compounds before annealing. All metal ion solutions precipitated out after 7 minutes of NaOH addition except in urea stabilizer, where the solution remained in the colloidal form for more than 30 minutes. The hydroxyl ions are required for ZnO formation, but it weakens chitosan and citric acid stabilizing capacity, which instigated ZnO particles to be highly agglomerated. Each stabilizer generated a smaller ZnO crystallite size compared to the control sample. Fe-ZnO crystallite size prepared using chitosan, citric acid and urea as the stabilizer was 14.75, 23.29 and 22.51 nm, respectively. The crystallite size of Fe-ZnO that was prepared without stabilizer (control) was 32.89 nm. © Published under licence by IOP Publishing Ltd.

关键词： Urea

Radial kinks in a Schwarzschild-like geometry

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arXiv 2024年

作者： Caputo, Jean-Guy Dobrowolski, Tomasz Gatlik, Jacek Kevrekidis, Panayotis G. Laboratoire de Mathématiques INSA de Rouen Avenue de l’Université Saint-Etienne du Rouvray76801 France Department of Computer Physics and Quantum Computing University of the National Education Commission in Krakow Podchoŗ azych 2 Cracow30-084 Poland AGH University of Krakow Faculty of Physics and Applied Computer Science Krakow30-059 Poland Department of Mathematics and Statistics University of Massachusetts AmherstMA01003-4515 United States

We study the propagation of a domain wall (kink) of the 4 model in a radially symmetric environment defined by a gravity source. This source introduces a Schwarzschild-like geometry. We introduce an effective model that accurately describes the dynamics of the kink center. This description works well even outside the perturbation region, i.e., even for large masses of the gravitating object. We observed that such a spherical domain wall surrounding a star-type object inevitably "collapses", i.e., shrinks in radius towards the origin and offer an understanding of the latter phenomenology. The relevant analysis is presented for a circular domain wall and a spherical one. © 2024, CC BY.

关键词： Spheres

Electrical Detection of Magnetization Switching in Single-Molecule Magnets

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arXiv 2024年

作者： Alqahtani, Amjad Henry, DaVonne Havlíček, Lubomír Marie, Luke St. Hrubý, Jakub Sojka, Antonín Hale, Morgan Felsenfeld, Samuel El Fatimy, Abdelouahad Myers-Ward, Rachael L. Kurt Gaskill, D. Nemec, Ivan Neugebauer, Petr Liu, Amy Y. Barbara, Paola Department of Physics Georgetown University WashingtonDC20057 United States Central European Institute of Technology CEITECBUT Purkyňova 656/123 Brno61200 Czech Republic Department of Math Computer Science and Physics Roanoke College RoanokeVA24153 United States Department of Physics University of Maryland College ParkMD20742 United States Institute of Applied Physics Mohammed VI Polytechnic University Lot 660 Hay Moulay Rachid Ben Guerir43150 Morocco U.S. Naval Research Laboratory WashingtonDC20375 United States Institute for Research in Electronics and Applied Physics University of Maryland College ParkMD20742 United States Department of Inorganic Chemistry Faculty of Science Palacký University Olomouc Olomouc77146 Czech Republic

Single-molecule magnets (SMMs) with chemically tailorable properties are potential building blocks for quantum computing, high-density magnetic memory, and spintronics.1 2 3,4 These applications require isolated or few molecules on substrates, but studies of SMMs have mainly focused on bulk crystals. Moreover, fabrication of SMM-based devices and electrical detection of the SMM magnetic state are still coveted milestones that have so far been achieved mainly for double-decker rare-earth phthalocyanines at temperatures below 1 K.5-8 Here we demonstrate electrical detection of magnetization switching for a modification of the archetypal SMM Mn12, up to 70 K, based on the supramolecular spin valve effect5 with graphene quantum dots9. Notably, the exchange interaction between the molecules and the graphene, as well as the dot-mediated intermolecular interaction, can be directly extracted from the electrical response, opening the way to an effective characterization of the quantum properties of different types of SMMs in a wide temperature range. Copyright © 2024, The Authors. All rights reserved.

关键词： Nanocrystals

Constraining f(R) models with cosmic chronometers and the HII galaxy Hubble diagram

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arXiv 2022年

作者： Sultana, Joseph Yennapureddy, Manoj K. Melia, Fulvio Kazanas, Demosthenes Department of Mathematics Faculty of Science University of Malta MSD Msida2080 Malta Department of Physics The University of Arizona TucsonAZ85721 United States Department of Physics The Applied Math Program Department of Astronomy The University of Arizona TucsonAZ85721 United States Astrophysics Science Division NASA/Goddard Space Flight Center GreenbeltMD20771 United States

We consider several well-known f(R) cosmological models and constrain their parameters, namely the deviation parameter b and the cosmological parameters Ωm and h. We first obtain analytical approximations for the Hubble rate H(z) and the luminosity distance dL(z) in terms of these parameters, and then test these against the observational expansion rate derived from cosmic chronometers and the distance modulus in the HII galaxy Hubble diagram, obtained in a model-independent way using Gaussian Processes (GP). We first optimize the models based solely on the cosmic chronometers and then repeat this process with a joint analysis using both the cosmic chronometers and HII galaxies. Copyright © 2022, The Authors. All rights reserved.

关键词： Chronometers

Beyond circular-arc graphs - recognizing lollipop graphs and medusa graphs

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arXiv 2022年

作者： Çağirici, Deniz Ağaoğlu Çağirici, Onur Derbisz, Jan Hartmann, Tim A. Hliněný, Petr Kratochvíl, Jan Krawczyk, Tomasz Zeman, Peter Masaryk University Brno Czech Republic Toronto Metropolitan University Toronto Canada Theoretical Computer Science Department Faculty of Mathematics and Computer Science Jagiellonian University Kraków Poland RWTH Aachen University Aachen Germany Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Prague Czech Republic Institut de Mathématiques University of Neuchâtel Switzerland

In 1992 Biró, Hujter and Tuza introduced, for every fixed connected graph H, the class of H-graphs, defined as the intersection graphs of connected subgraphs of some subdivision of H. Such classes of graphs are related to many known graph classes: for example, K2-graphs correspond to interval graphs, K3-graphs correspond to circular-arc graphs, the union of T-graphs, where T ranges over all trees, correspond to chordal graphs. Recently, quite a lot of research has been devoted to understanding the tractability border for various computational problems, such as recognition or isomorphism testing, in classes of H-graphs for different graphs H. In this work we undertake this research topic, focusing on the recognition problem. Chaplick, Töpfer, Voborník, and Zeman showed an XP-algorithm testing whether a given graph is a T-graph, where the parameter is the size of the tree T. In particular, for every fixed tree T the recognition of T-graphs can be solved in polynomial time. Tucker showed a polynomial time algorithm recognizing K3-graphs (circular-arc graphs). On the other hand, Chaplick at al. showed also that recognition of H-graphs is NP-hard if H contains two different cycles sharing an edge. The main two results of this work narrow the gap between the NP-hard and P cases of H-graphs recognition. First, we show that recognition of H-graphs is NP-hard when H contains two different cycles. On the other hand, we show a polynomial-time algorithm recognizing L-graphs, where L is a graph containing a cycle and an edge attached to it (L is called a lollipop and L-graphs are called lollipop graphs). Clearly, the class of lollipop graphs extends the class of circular-arc graphs. Our work leaves open the recognition problems of M-graphs for every unicyclic graph M different from a cycle and a lollipop. Other results of this work, which shed some light on the cases that remain open, are as follows: • recognition of M-graphs, where M is a fixed unicyclic graph, admits a polynom

关键词： Polynomial approximation