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A method for time calibration of PET systems using fixed β+ radioactive source

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A method for time calibration of PET systems using fixed β+...

作者： Dulski, K. Silarski, M. Moskal, P. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland

A method for the time calibration of the Time-of-Flight Positron Em-mission Tomograph (TOF-PET) systems using fixed sources is described. Compared to the commercially used calibration methods, the new method gives a chance to run the calibration during the medical scan. Reduction of the time needed for calibration can increase the number of patients examined by PET. The process of calibration of the Jagiellonian Positron Emission Tomograph (J-PET) detector is shown as an example. © 2020 Jagellonian university. All rights reserved.

关键词： Calibration

Hybrid algorithm for detecting intrusion with optical fiber sensor in rainy weather

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Optik 2024年 311卷

作者： Chebaane, Saleh Ben Khalifa, Sana Louati, Ali Bahri, Haythem Saidani, Taoufik Department of Physics College of Science University of Ha'il P.O. Box 2240 Ha'il Saudi Arabia Faculty of Sciences of Monastir University of Monastir Monastir Tunisia Department of Physics College of Science Qassim University P.O.Box 6644 Almolaydah Buraydah51452 Saudi Arabia ESSTHS University of Sousse Sousse4011H Tunisia Department of Information Systems College of Computer Engineering and Sciences Prince Sattam Bin Abdulaziz University Al-Kharj 11942 Saudi Arabia UGA University of Grenoble Alpes and member in GIPSA Laboratory France Department of Computer Sciences Faculty of Computing and Information Technology Northern Border University Rafha91911 Saudi Arabia

Fiber optic intrusion detection is recognized as one of the most effective perimeter defense strategies against intruders and terrorists. Most current infiltration detection systems gather information via optical cables and trace invasions using classification techniques. This research introduces two intrusion detection algorithms and a hybrid approach to address the challenges of unstable and hard-to-extract fiber optic infiltration features, especially during rainy weather. The first method, known as the phase parameter-matching algorithm, calculates the system's disturbance covariance at any position and uses the Frobenius norm to identify intrusions by measuring the difference between disturbance covariances at distinct sites. The second method, the cross-rebuilding algorithm, employs the Kalman filter to reconstruct the output of each point based on the non-infiltration state parameters, detecting intrusions through cross-reconstruction error. Experimental tests were conducted to evaluate both methods. The results indicate that both methods are viable, with the phase parameter-matching algorithm being more robust but slower, and the cross-rebuilding algorithm being faster but less reliable. The hybrid algorithm combines the strengths of both approaches, offering a balanced solution with moderate computation time and enhanced resistance to environmental interference, leading to improved overall detection accuracy and reduced false positive rates. © 2024 Elsevier GmbH

关键词： Intrusion detection

Hinge modes and surface states in second-order topological three-dimensional quantum Hall systems induced by charge density modulation

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Physical Review B 2020年第12期102卷 125126-125126页

作者： Paweł Szumniak Daniel Loss Jelena Klinovaja AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland Department of Physics University of Basel Klingelbergstrasse 82 4056 Basel Switzerland

We consider a system of weakly coupled one-dimensional wires forming a three-dimensional stack in the presence of a spatially periodic modulation of the chemical potential along the wires, equivalent to a charge density wave (CDW). An external static magnetic field is applied parallel to the wire axes. We show that, for a certain parameter regime, due to interplay between the CDW and magnetic field, the system can support a second-order topological phase characterized by the presence of chiral quasi-1D quantum Hall effect (QHE) hinge modes. Interestingly, we demonstrate that direction of propagation of the hinge modes depends on the phase of the CDW and can be reversed only by electrical means without the need of changing the orientation of the magnetic field. Furthermore, we show that the system can also support 2D chiral surface QHE states, which can coexist with one-dimensional hinge modes, realizing a scenario of a hybrid high-order topology. Performing two-terminal transport simulations in the linear response regime, we confirm quantized QHE resistance plateaus, which are highly robust to disorder giving a clear signature of hinge and surface states.

关键词： Edge states Hall effect Topological materials

Exploring the integration of multi criteria decision analysis in the clean energy biodiesels applications: A systematic review and gap analysis

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Engineering Applications of Artificial Intelligence 2024年 133卷

作者： Alamoodi, A.H. Garfan, Salem Al-Zuhairi, Omar Zaidan, B.B. Zaidan, A.A. Albahri, O.S. Y.Y. Ahmaro, Ibraheem Albahri, A.S. Yussof, Salman Magableh, Aws A. Institute of Informatics and Computing in Energy Universiti Tenaga Nasional Malaysia Hourani Center for Applied Scientific Research Al-Ahliyya Amman University Amman19328 Jordan Perak Malaysia Applied Science Research Center Applied Science Private University Amman Jordan Low Dimensional Materials Research Centre Department of Physics Faculty of Science Universiti Malaya Kuala Lumpur50603 Malaysia SP Jain School of Global Management Lidcombe SydneyNSW2141 Australia International Graduate School of Artificial Intelligence National Yunlin University of Science and Technology Douliu Taiwan Victorian Institute of Technology Australia Computer Techniques Engineering Department Mazaya University College Nasiriyah Iraq Computer Science Department College of Information Technology Hebron University Hebron Palestine Technical College Imam Ja'afar Al-Sadiq University Baghdad Iraq Department of Information Systems Yarmouk University Irbid Jordan Baghdad Iraq Department of Computing College of Computing and Informatics Universiti Tenaga Nasional Malaysia Departments of Software Engineering Prince Sultan University Riyad Saudi Arabia

Biodiesel has gained tremendous attention from researchers due to its environmentally friendly and renewable fuel manufactured domestically from vegetable oils or animal fats. Multiple factors, including emission and fuel efficiency, measure the performance of biodiesel. These characteristics make the process of evaluation and benchmarking a multi-criteria decision-making (MCDM) problem. This research attempts to survey the literature for multi-criteria decision-making applications on biodiesel. This systematic review was carried out on four scientific databases: PubMed, scienceDirect, IEEE Xplore, and WoS. The collected articles were summarized and mapped into a coherent taxonomy, while the main challenges, motivations, and recommendations were collected and categorized for better understanding and finding out essential characteristics. The final set of included articles was 33, and they were categorized into six different categories. Most articles (n=15/33) investigated the evaluation and selection of biodiesel alternatives using MCDM. Furthermore, a state-of-art bibliometric analysis is provided. The analysis demonstrates several challenges in this area, such as source selection, optimum fuel blending, and uncertainty. This article is expected to assist future researchers in addressing the current gaps and contribute to advancing this area. © 2024 Elsevier Ltd

关键词： Biodiesel

Deep Learning Assisted Raman Spectroscopy for Rapid Identification of 2D Materials

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arXiv 2023年

作者： Qi, Yaping Hu, Dan Wu, Zhenping Zheng, Ming Cheng, Guanghui Jiang, Yucheng Chen, Yong P. Department of Engineering Science Faculty of Innovation Engineering Macau University of Science and Technology Av. Wai Long 999078 China Tohoku University Sendai980-8577 Japan State Key Laboratory of Information Photonics and Optical Communications School of Science Beijing University of Posts and Telecommunications Beijing100876 China School of Materials Science and Physics China University of Mining and Technology Xuzhou221116 China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and Technology Suzhou University of Science and Technology Jiangsu Suzhou215009 China Department of Physics and Astronomy Elmore Family School of Electrical and Computer Engineering Birck Nanotechnology Center Purdue Quantum Science and Engineering Institute Purdue University West LafayetteIN47907 United States Institute of Physics and Astronomy Villum Center for Hybrid Quantum Materials and Devices Aarhus University AarhusC 8000 Denmark

Two-dimensional (2D) materials have attracted extensive attention due to their unique characteristics and application potentials. Raman spectroscopy, as a rapid and non-destructive probe, exhibits distinct features and holds notable advantages in the structural characterization of 2D materials. However, traditional data analysis of Raman spectra relies on manual interpretation and feature extraction, which are both time-consuming and subjective. In this work, we employ deep learning techniques, including classificatory and generative deep learning, to assist the analysis of Raman spectra of typical 2D materials. For the limited and unevenly distributed Raman spectral data, we propose a data augmentation approach based on Denoising Diffusion Probabilistic Models (DDPM) to augment the training dataset and construct a four-layer Convolutional Neural Network (CNN) for 2D material classification. Experimental results illustrate the effectiveness of DDPM in addressing data limitations and significantly improved classification model performance. The proposed DDPM-CNN method shows high reliability, with 100%classification accuracy. Our work demonstrates the practicality of deep learning-assisted Raman spectroscopy for high-precision recognition and classification of 2D materials, offering a promising avenue for rapid and automated spectral analysis. © 2023, CC BY.

关键词： Raman spectroscopy

Work fluctuations due to partial thermalizations in two-level systems

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Physical Review E 2021年第4期103卷 042141-042141页

作者： Maria Quadeer Kamil Korzekwa Marco Tomamichel Centre for Quantum Software and Information School of Computer Science University of Technology Sydney Ultimo NSW 2007 Australia Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University 30-348 Kraków Poland Department of Electrical and Computer Engineering & Centre for Quantum Technologies National University of Singapore Singapore 119077

We study work extraction processes mediated by finite-time interactions with an ambient bath—partial thermalizations—as continuous-time Markov processes for two-level systems. Such a stochastic process results in fluctuations in the amount of work that can be extracted and is characterized by the rate at which the system parameters are driven in addition to the rate of thermalization with the bath. We analyze the distribution of work for the case in which the energy gap of a two-level system is driven at a constant rate. We derive analytic expressions for average work and a lower bound for the variance of work showing that such processes cannot be fluctuation-free in general. We also observe that an upper bound for the Monte Carlo estimate of the variance of work can be obtained using Jarzynski's fluctuation-dissipation relation for systems initially in equilibrium. Finally, we analyze work extraction cycles by modifying the Carnot cycle, incorporating processes involving partial thermalizations, and we obtain efficiency at maximum power for such finite-time work extraction cycles under different sets of constraints.

关键词： Fluctuation theorems Irreversible processes Nonequilibrium statistical mechanics

Selected topics on Wiener index

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arXiv 2023年

作者： Knor, Martin Škrekovski, Riste Tepeh, Aleksandra Slovak University of Technology in Bratislava Faculty of Civil Engineering Department of Mathematics Bratislava Slovakia FMF University of Ljubljana Faculty of Information Studies Novo mesto & Institute of Mathematics Physics and Mechanics Ljubljana & University of Primorska FAMNIT Koper Slovenia Faculty of Information Studies Novo mesto & Faculty of Electrical Engineering and Computer Science University of Maribor Slovenia

The Wiener index is defined as the sum of distances between all unordered pairs of vertices in a graph. It is one of the most recognized and well-researched topological indices, which is on the other hand still a very active area of research. This work presents a natural continuation of the paper Mathematical aspects of Wiener index (Ars Math. Contemp., 2016) in which several interesting open questions on the topic were outlined. Here we collect answers gathered so far, give further insights on the topic of extremal values of Wiener index in different settings, and present further intriguing problems and conjectures. © 2023, CC BY.

关键词： Graph theory

Structure of betweenness uniform graphs with low values of betweenness centrality

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arXiv 2023年

作者： Ghanbari, Babak Hartman, David Jelínek, Vít Pokorná, Aneta Šámal, Robert Valtr, Pavel Computer Science Institute of Charles University Faculty of Mathematics and Physics Charles University Malostranské nám. 25 Prague 111800 Czech Republic Institute of Computer Science of the Czech Academy of Sciences Czech Academy of Sciences Pod Vodárenskou věží 271/2 Prague 818207 Czech Republic Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Malostranské náměstí 25 Prague 111800 Czech Republic

This work deals with undirected graphs that have the same betweenness centrality for each vertex, so-called betweenness uniform graphs (or BUGs). The class of these graphs is not trivial and its classification is still an open problem. Recently, Gago, Coroničová-Hurajová and Madaras conjectured that for every rational α ≥ 3/4 there exists a BUG having betweenness centrality α. We disprove this conjecture, and provide an alternative view of the structure of betweenness-uniform graphs from the point of view of their complement. This allows us to characterise all the BUGs with betweennes centrality at most 9/10, and show that their betweenness centrality is equal to +1 for some integer ≤ 9. We conjecture that this characterization extends to all the BUGs with betweenness centrality smaller than *** Codes 05C12, 05C75, 05C82 Copyright © 2023, The Authors. All rights reserved.

关键词： Graphic methods

On ordered Ramsey numbers of tripartite 3-uniform hypergraphs

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arXiv 2022年

作者： Balko, Martin Vizer, Máté Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Czech Republic Alfréd Rényi Institute of Mathematics ELKH Budapest Hungary Department of Computer Science and Information Theory Budapest University of Technology and Economic Hungary

For an integer k ≥ 2, an ordered k-uniform hypergraph H = (H, N(k) on N vertices contains a blue copy of H or a red copy of G. The ordered Ramsey numbers are quite extensively studied for ordered graphs, but little is known about ordered hypergraphs of higher uniformity. We provide some of the first nontrivial estimates on ordered Ramsey numbers of ordered 3-uniform hypergraphs. In particular, we prove that for all d, n ∈ and for every ordered 3-uniform hypergraph H on n vertices with maximum degree d and with interval chromatic number 3 there is an Ε = Ε(d) > 0 such that (Equation presented). In fact, we prove this upper bound for the number (Equation presented), where G is an ordered 3-uniform hypergraph with n vertices and maximum degree d and K3(3)(n) is the ordered complete tripartite hypergraph with consecutive color classes of size n. We show that this bound is not far from the truth by proving (Equation presented) for some fixed ordered 3-uniform hypergraph H. © 2022, CC BY.

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