1,300 results
Search Results
302. Physical and Mechanical Properties Evolution of Coal Subjected to Salty Solution and a Damage Constitutive Model under Uniaxial Compression
- Author
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Min Wang, Qifeng Guo, Yakun Tian, and Bing Dai
- Subjects
coal ,General Mathematics ,technology, industry, and agriculture ,deterioration characteristics ,chemical-stress coupling factor ,damage constitutive model ,complex mixtures ,respiratory tract diseases ,Computer Science (miscellaneous) ,otorhinolaryngologic diseases ,QA1-939 ,Engineering (miscellaneous) ,Mathematics - Abstract
Many underground reservoirs for storing water have been constructed in China’s western coal mines to protect water resources. Coal pillars which work as dams are subjected to a long-term soaking environment of concentrated salty water. Deterioration of the coal dam under the attack of the salty solution poses challenges for the long-term stability and serviceability of underground reservoirs. The evolution of the physical and mechanical properties of coal subjected to salty solutions are investigated in this paper. Coal from a western China mine is made to standard cylinder samples. The salty solution is prepared according to chemical tests of water in the mine. The coal samples soaked in the salty solution for different periods are tested by scanning electron microscope, nuclear magnetic resonance, and ultrasonic detector techniques. Further, uniaxial compression tests are carried out on the coal specimens. The evolutions of porosity, mass, microstructures of coal, solution pH values, and stress–strain curves are obtained for different soaking times. Moreover, a damage constitutive model for the coal samples is developed by introducing a chemical-stress coupling damage variable. The result shows that the corrosion effect of salty solution on coal samples becomes stronger with increasing immersion time. The degree of deterioration of the longitudinal wave velocity (vp) is positively correlated with the immersion time. With the increase in soaking times, the porosity of coal gradually increases. The relative mass firstly displays an increasing trend and then decreases with time. The peak strength and elastic modulus of coal decreases exponentially with soaking times. The developed damage constitutive model can well describe the stress–strain behavior of coal subjected to salty solution under the uniaxial compression.
- Published
- 2021
303. Continuity and Analyticity for the Generalized Benjamin–Ono Equation
- Author
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Xiaolin Pan, Bin Wang, and Rong Chen
- Subjects
Physics and Astronomy (miscellaneous) ,Hölder continuous ,General Mathematics ,Mathematics::Analysis of PDEs ,MathematicsofComputing_GENERAL ,Gevrey regularity ,generalized Benjamin–Ono equation ,non-uniform dependence ,symmetry ,analyticity ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,QA1-939 ,Mathematics - Abstract
This work mainly focuses on the continuity and analyticity for the generalized Benjamin–Ono (g-BO) equation. From the local well-posedness results for g-BO equation, we know that its solutions depend continuously on their initial data. In the present paper, we further show that such dependence is not uniformly continuous in Sobolev spaces Hs(R) with s>3/2. We also provide more information about the stability of the data-solution map, i.e., the solution map for g-BO equation is Hölder continuous in Hr-topology for all 0≤r
- Published
- 2021
304. Applying GMEI-GAN to Generate Meaningful Encrypted Images in Reversible Data Hiding Techniques
- Author
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Chwei-Shyong Tsai, Hsien-Chu Wu, Yu-Wen Li, and Josh Jia-Ching Ying
- Subjects
Physics and Astronomy (miscellaneous) ,reversible data hiding ,General Mathematics ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,convolutional neural network ,Data_CODINGANDINFORMATIONTHEORY ,symmetric encryption ,generative adversarial networks ,residual learning ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,QA1-939 ,Mathematics - Abstract
With the rapid development of information technology, the transmission of information has become convenient. In order to prevent the leakage of information, information security should be valued. Therefore, the data hiding technique has become a popular solution. The reversible data hiding technique (RDH) in particular uses symmetric encoding and decoding algorithms to embed the data into the cover carrier. Not only can the secret data be transmitted without being detected and retrieved completely, but the cover carrier also can be recovered without distortion. Moreover, the encryption technique can protect the carrier and the hidden data. However, the encrypted carrier is a form of ciphertext, which has a strong probability to attract the attention of potential attackers. Thus, this paper uses the generative adversarial networks (GAN) to generate meaningful encrypted images for RDH. A four-stage network architecture is designed for the experiment, including the hiding network, the encryption/decryption network, the extractor, and the recovery network. In the hiding network, the secret data are embedded into the cover image through residual learning. In the encryption/decryption network, the cover image is encrypted into a meaningful image, called the marked image, through GMEI-GAN, and then the marked image is restored to the decrypted image via the same architecture. In the extractor, 100% of the secret data are extracted through the residual learning framework, same as the hiding network. Lastly, in the recovery network, the cover image is reconstructed with the decrypted image and the retrieved secret data through the convolutional neural network. The experimental results show that using the PSNR/SSIM as the criteria, the stego image reaches 45.09 dB/0.9936 and the marked image achieves 38.57 dB/0.9654. The proposed method not only increases the embedding capacity but also maintains high image quality in the stego images and marked images.
- Published
- 2021
305. Fluid-Flow Approximation in the Analysis of Vast Energy-Aware Networks
- Author
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Tadeusz Czachorski, Monika Nycz, and Tomasz Nycz
- Subjects
General Mathematics ,data analysis ,Computer Science (miscellaneous) ,QA1-939 ,fluid-flow approximation ,computer networks ,energy-aware networks ,Engineering (miscellaneous) ,Mathematics - Abstract
The paper addresses two issues: (i) modeling dynamic flows transmitted in vast TCP/IP networks and (ii) modeling the impact of energy-saving algorithms. The approach is based on the fluid-flow approximation, which applies first-order differential equations to analyze the evolution of queues and flows. We demonstrate that the effective implementation of this method overcomes the constraints of storing large data in numerical solutions of transient problems in vast network topologies. The model is implemented and executed directly in a database system. It can analyze transient states in topologies of more than 100,000 nodes, i.e., the size which was not considered until now. We use it to investigate the impact of an energy-saving algorithm on the performance of a vast network. We find that it reduces network congestion and save energy costs but significantly lower network throughput.
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- 2021
306. η-∗-Ricci Solitons and Almost co-Kähler Manifolds
- Author
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Arpan Sardar, Mohammad Nazrul Islam Khan, and Uday Chand De
- Subjects
(k,μ)-almost co-Kähler manifolds ,General Mathematics ,MathematicsofComputing_GENERAL ,gradient η-∗-Ricci solitons ,almost co-Kähler manifolds ,Nonlinear Sciences::Exactly Solvable and Integrable Systems ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Computer Science (miscellaneous) ,QA1-939 ,Mathematics::Differential Geometry ,η-∗-Ricci solitons ,Nonlinear Sciences::Pattern Formation and Solitons ,Engineering (miscellaneous) ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,∗-Ricci tensor ,Mathematics - Abstract
The subject of the present paper is the investigation of a new type of solitons, called η-∗-Ricci solitons in (k,μ)-almost co-Kähler manifold (briefly, ackm), which generalizes the notion of the η-Ricci soliton introduced by Cho and Kimura. First, the expression of the ∗-Ricci tensor on ackm is obtained. Additionally, we classify the η-∗-Ricci solitons in (k,μ)-ackms. Next, we investigate (k,μ)-ackms admitting gradient η-∗-Ricci solitons. Finally, we construct two examples to illustrate our results.
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- 2021
307. On Stability Switches and Bifurcation of the Modified Autonomous Van der Pol–Duffing Equations via Delayed State Feedback Control
- Author
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Tiao-Yang Cai, Hui-Long Jin, Hong Yu, and Xiang-Peng Xie
- Subjects
Physics and Astronomy (miscellaneous) ,center manifold theory ,Chemistry (miscellaneous) ,General Mathematics ,Computer Science (miscellaneous) ,QA1-939 ,stability switches ,Hopf bifurcation ,τ-decomposition method ,Mathematics - Abstract
This paper considers the Modified Autonomous Van der Pol–Duffing equation subjected to dynamic state feedback, which can well characterize the dynamic behaviors of the nonlinear dynamical systems. Both the issues of local stability switches and the Hopf bifurcation versus time delay are investigated. Associating with the τ decomposition strategy and the center manifold theory, the delay stable intervals and the direction and stability of the Hopf bifurcation are all determined. Specifically, the computation of purely imaginary roots (symmetry to the real axis), the positive real root formula for cubic equation and the sophisticated bilinear form of adjoint operators are proposed, which make the calculations mentioned in our discussion unified and simple. Finally, the typical numerical examples are shown to illustrate the correctness and effectiveness of the practical technique.
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- 2021
308. On the Semi-Local Convergence of an Ostrowski-Type Method for Solving Equations
- Author
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Samundra Regmi, Ioannis K. Argyros, Christopher I. Argyros, Janak Joshi, and Santhosh George
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Banach space ,Physics and Astronomy (miscellaneous) ,Iterative method ,General Mathematics ,Physical system ,Ostrowski-type method ,Symmetry (physics) ,Local convergence ,convergence criterion ,Chemistry (miscellaneous) ,Iterated function ,Convergence (routing) ,Computer Science (miscellaneous) ,QA1-939 ,Applied mathematics ,Mathematics ,Equation solving - Abstract
Symmetries play a crucial role in the dynamics of physical systems. As an example, microworld and quantum physics problems are modeled on principles of symmetry. These problems are then formulated as equations defined on suitable abstract spaces. Then, these equations can be solved using iterative methods. In this article, an Ostrowski-type method for solving equations in Banach space is extended. This is achieved by finding a stricter set than before containing the iterates. The convergence analysis becomes finer. Due to the general nature of our technique, it can be utilized to enlarge the utilization of other methods. Examples finish the paper.
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- 2021
309. Starlikeness of New General Differential Operators Associated with q-Bessel Functions
- Author
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Loriana Andrei and Vasile-Aurel Caus
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analytic functions ,univalent functions ,q-starlike functions ,q-difference operator ,differential subordination ,q-Bessel functions ,Pure mathematics ,Class (set theory) ,Physics and Astronomy (miscellaneous) ,General Mathematics ,Differential operator ,Alpha (programming language) ,symbols.namesake ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,symbols ,QA1-939 ,Order (group theory) ,Bessel function ,Mathematics ,Analytic function - Abstract
Owning to the importance and great interest of differential operators, two generalized differential operators, which may be symmetric or assymetric, are newly introduced in the present paper. Motivated by the familiar Jackson’s second and third Bessel functions, we derive necessary and sufficient conditions for which the new generalized operators belong to the class of q-starlike functions of order alpha. Several corollaries and consequences of the main results are also pointed out.
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- 2021
310. Some New Reverse Hilbert’s Inequalities on Time Scales
- Author
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Ghada AlNemer, Ahmed I. Saied, Mohammed Zakarya, Hoda A. Abd El-Hamid, Omar Bazighifan, and Haytham M. Rezk
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Physics and Astronomy (miscellaneous) ,Chemistry (miscellaneous) ,General Mathematics ,time scales ,Computer Science (miscellaneous) ,Specht’s ratio ,QA1-939 ,reverse Hilbert-type inequalities ,reverse Hölder inequalities ,Mathematics - Abstract
This paper is interested in establishing some new reverse Hilbert-type inequalities, by using chain rule on time scales, reverse Jensen’s, and reverse Hölder’s with Specht’s ratio and mean inequalities. To get the results, we used the Specht’s ratio function and its applications for reverse inequalities of Hilbert-type. Symmetrical properties play an essential role in determining the correct methods to solve inequalities. The new inequalities in special cases yield some recent relevance, which also provide new estimates on inequalities of these type.
- Published
- 2021
311. A Study on Nonlinear Dynamic Response of the Large-Span Roof Structure with Suspended Substructure
- Author
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Rui Pan, Baofeng Zheng, and Ying Qin
- Subjects
analytical solution ,large-span roof structure ,Physics and Astronomy (miscellaneous) ,substructure ,Chemistry (miscellaneous) ,nonlinear vibration ,General Mathematics ,Computer Science (miscellaneous) ,QA1-939 ,Mathematics - Abstract
Nowadays, it is common to see large public buildings, e.g., stadiums, with some equipment or substructure suspended from the center of the roof. These substructures will tend to be larger and heavier the more gear is needed, which may have negative impacts on the dynamic performance of the roof structures. In this paper, to explore the dynamic response of a large-span roof structure with a suspended substructure, a real structure model is simplified into a two-degrees-of-freedom system. The essential consideration of nonlinear vibration is elaborated in the equations of motions. Approximate analytical solutions for free and forced vibrations are derived using perturbation methods, while numerical analysis is carried out to validate the solutions. The ratio of linear to nonlinear amplitude is proposed to represent the nonlinear effect of the primary structure, and the nonlinear effect, varying with structural parameters of frequency ratio, mass ratio, excitation ratio, and external force to the primary structure, is investigated. It is shown that internal resonance occurs when the structural frequency ratio is close to 1:2 and that secondary resonance takes place due to certain external excitations; internal resonance and secondary resonance will magnify the amplitude of the primary structure during vibration. Finally, a case of a designed practical dome with a suspended substructure is studied to verify the outcomes from the above research. According to these findings, some design proposals for this type of structure are provided.
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- 2021
312. Approximations of Symmetric Functions on Banach Spaces with Symmetric Bases
- Author
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Andriy Zagorodnyuk and Maria Martsinkiv (Dubei)
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symmetric functions on Banach spaces ,approximations by analytic functions ,invariant means ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Physics and Astronomy (miscellaneous) ,Chemistry (miscellaneous) ,General Mathematics ,Computer Science (miscellaneous) ,MathematicsofComputing_GENERAL ,QA1-939 ,Computer Science::Programming Languages ,Mathematics - Abstract
This paper is devoted to studying approximations of symmetric continuous functions by symmetric analytic functions on a Banach space X with a symmetric basis. We obtain some positive results for the case when X admits a separating polynomial using a symmetrization operator. However, even in this case, there is a counter-example because the symmetrization operator is well defined only on a narrow, proper subspace of the space of analytic functions on X. For X=c0, we introduce ε-slice G-analytic functions that have a behavior similar to G-analytic functions at points x∈c0 such that all coordinates of x are greater than ε, and we prove a theorem on approximations of uniformly continuous functions on c0 by ε-slice G-analytic functions.
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- 2021
313. Multi-UAV Cooperative Task Assignment Based on Half Random Q-Learning
- Author
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Pengxing Zhu and Xi Fang
- Subjects
task allocation ,half-random Q-learning ,UAV collaboration ,random exploration ,Physics and Astronomy (miscellaneous) ,Chemistry (miscellaneous) ,General Mathematics ,Computer Science (miscellaneous) ,QA1-939 ,Mathematics - Abstract
Unmanned aerial vehicle (UAV) clusters usually face problems such as complex environments, heterogeneous combat subjects, and realistic interference factors in the course of mission assignment. In order to reduce resource consumption and improve the task execution rate, it is very important to develop a reasonable allocation plan for the tasks. Therefore, this paper constructs a heterogeneous UAV multitask assignment model based on several realistic constraints and proposes an improved half-random Q-learning (HR Q-learning) algorithm. The algorithm is based on the Q-learning algorithm under reinforcement learning, and by changing the way the Q-learning algorithm selects the next action in the process of random exploration, the probability of obtaining an invalid action in the random case is reduced, and the exploration efficiency is improved, thus increasing the possibility of obtaining a better assignment scheme, this also ensures symmetry and synergy in the distribution process of the drones. Simulation experiments show that compared with Q-learning algorithm and other heuristic algorithms, HR Q-learning algorithm can improve the performance of task execution, including the ability to improve the rationality of task assignment, increasing the value of gains by 12.12%, this is equivalent to an average of one drone per mission saved, and higher success rate of task execution. This improvement provides a meaningful attempt for UAV task assignment.
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- 2021
314. Solving an Integral Equation via Fuzzy Triple Controlled Bipolar Metric Spaces
- Author
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Gunaseelan Mani, Arul Joseph Gnanaprakasam, Zoran D. Mitrović, and Monica-Felicia Bota
- Subjects
General Mathematics ,fuzzy bipolar metric space ,fixed points ,Computer Science (miscellaneous) ,fuzzy triple controlled bipolar metric space ,QA1-939 ,fuzzy metric space ,Engineering (miscellaneous) ,Mathematics - Abstract
In this paper, motivated by the recent result of Sezen, we introduce the notion of fuzzy triple controlled bipolar metric space and prove some fixed point results in this framework. Our results generalize and extend some of the well-known results from the literature. We also explore some of the applications of our key results to integral equations.
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- 2021
315. MP-CE Method for Space-Filling Design in Constrained Space with Multiple Types of Factors
- Author
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Yang You, Guang Jin, Zhengqiang Pan, and Rui Guo
- Subjects
experimental design ,General Mathematics ,multiple types of factors ,Computer Science (miscellaneous) ,QA1-939 ,space-filling ,Engineering (miscellaneous) ,Mathematics - Abstract
Space-filling design selects points uniformly in the experimental space, bringing considerable flexibility to the complex-model-based and model-free data analysis. At present, space-filling designs mostly focus on regular spaces and continuous factors, with a lack of studies into the discrete factors and the constraints among factors. Most of the existing experimental design methods for qualitative factors are not applicable for discrete factors, since they ignore the potential order or spatial distance between discrete factors. This paper proposes a space-filling method, called maximum projection coordinate-exchange (MP-CE), taking into account both the diversity of factor types and the complexity of factor constraints. Specifically, the maximum projection criterion and distance criterion are introduced to capture the “bad” coordinates, and the coordinate-exchange and the optimization of experimental design are realized by solving one-dimensional constrained optimization problem. Meanwhile, by adding iterative perturbations to the traditional coordinate exchange process, the adjacent areas of the local optimal solution are explored and the optimum performances of the current optimal solution are retained, while the shortcomings of random restart are effectively avoided. Experiments in the regular space and constraint space, as well as experimental design for the terminal interception effectiveness of a missile defense system, show that the MP-CE method significantly outperforms existing popular space-filling design methods in terms of space-projection properties, while yielding comparable or superior space-filling properties.
- Published
- 2021
316. Existence and Global Attractivity of Pseudo Almost Periodic Solutions for Clifford-Valued Fuzzy Neural Networks with Proportional Delays
- Author
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Wen Lv and Bing Li
- Subjects
General Mathematics ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,Computer Science (miscellaneous) ,QA1-939 ,Clifford-valued neural networks ,pseudo almost periodic solutions ,fuzzy neural networks ,Engineering (miscellaneous) ,proportional delays ,global attractivity ,Mathematics - Abstract
In this paper, Clifford-valued fuzzy neural networks with proportional delays, whose leakage term coefficients are also Clifford numbers, are considered. Based on the Banach fixed point theorem and differential inequality technique, we use a direct method to obtain the existence, uniqueness, and global attractivity of pseudo almost periodic solutions for the considered networks. Finally, we provide a numerical example to illustrate the feasibility of our results. Our results are new.
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- 2021
317. Optimal Claim Settlement Strategies under Constraint of Cap on Claim Loss
- Author
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Hong Mao and Krzysztof Ostaszewski
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General Mathematics ,Computer Science (miscellaneous) ,claim cap ,QA1-939 ,insurance claim ,insurance contract ,insured loss ,Engineering (miscellaneous) ,Mathematics - Abstract
In this paper, we examine the question of how to devise an optimal insurance claim settlement scheme under the constraint of a cap on the amount of the claim payment. We establish objective functions to maximize the net benefit due to exaggerated claims while at the same time maximizing the total expected wealth of the insured. Then, we establish a dual objective function to minimize the total expected loss, including the perspective of the insurer. Finally, we illustrate applications of our work and provide numerical analysis of it along with an example.
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- 2021
318. The Values of the Periodic Zeta-Function at the Nontrivial Zeros of Riemann’s Zeta-Function
- Author
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Janyarak Tongsomporn, Saeree Wananiyakul, and Jörn Steuding
- Subjects
zeta-functions ,Riemann hypothesis ,Physics and Astronomy (miscellaneous) ,Chemistry (miscellaneous) ,General Mathematics ,Computer Science (miscellaneous) ,QA1-939 ,ddc:510 ,Mathematics - Abstract
In this paper, we prove an asymptotic formula for the sum of the values of the periodic zeta-function at the nontrivial zeros of the Riemann zeta-function (up to some height) which are symmetrical on the real line and the critical line. This is an extension of the previous results due to Garunkštis, Kalpokas, and, more recently, Sowa. Whereas Sowa’s approach was assuming the yet unproved Riemann hypothesis, our result holds unconditionally.
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- 2021
319. Generalized Confidence Intervals for Zero-Inflated Pareto Distribution
- Author
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Xiao Wang and Xinmin Li
- Subjects
fiducial generalized confidence interval ,General Mathematics ,coverage probability ,Computer Science (miscellaneous) ,QA1-939 ,zero-inflated Pareto distribution ,fiducial generalized pivotal quantity ,Engineering (miscellaneous) ,Mathematics - Abstract
This paper considers interval estimations for the mean of Pareto distribution with excess zeros. Three approaches for interval estimation are proposed based on fiducial generalized pivotal quantities (FGPQs), respectively. Simulation studies are performed to assess the performance of the proposed methods, along with three measurements to determine comparisons with competing approaches. The advantages and disadvantages of each method are provided. The methods are illustrated using a real phone call dataset.
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- 2021
320. PURA-SCIS Protocol: A Novel Solution for Cloud-Based Information Sharing Protection for Sectoral Organizations
- Author
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Fandi Aditya Putra, Kalamullah Ramli, Nur Hayati, and Teddy Surya Gunawan
- Subjects
cyber incident information sharing ,privacy preservation ,data protection ,Physics and Astronomy (miscellaneous) ,sectoral organizations ,Chemistry (miscellaneous) ,classified information ,General Mathematics ,Computer Science (miscellaneous) ,secure protocol ,QA1-939 ,Mathematics - Abstract
Over recent years, the incidence of data breaches and cyberattacks has increased significantly. This has highlighted the need for sectoral organizations to share information about such events so that lessons can be learned to mitigate the prevalence and severity of cyber incidents against other organizations. Sectoral organizations embody a governance relationship between cross-sector public and private entities, called public-private partnerships (PPPs). However, organizations are hesitant to share such information due to a lack of trust and business-critical confidentially issues. This problem occurs because of the absence of any protocols that guarantee privacy protection and protect sensitive information. To address this issue, this paper proposes a novel protocol, Putra-Ramli Secure Cyber-incident Information Sharing (PURA-SCIS), to secure cyber incident information sharing. PURA-SCIS has been designed to offer exceptional data and privacy protection and run on the cloud services of sectoral organizations. The relationship between organizations in PURA-SCIS is symmetrical, where the entities must collectively maintain the security of classified cyber incident information. Furthermore, the organizations must be legitimate entities in the PURA-SCIS protocol. The Scyther tool was used for protocol verification in PURA-SCIS. The experimental results showed that the proposed PURA-SCIS protocol provided good security properties, including public verifiability for all entities, blockless verification, data privacy preservation, identity privacy preservation and traceability, and private information sharing. PURA-SCIS also provided a high degree of confidentiality to protect the security and integrity of cyber-incident-related information exchanged among sectoral organizations via cloud services.
- Published
- 2021
321. Boosting Atomic Orbit Search Using Dynamic-Based Learning for Feature Selection
- Author
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Mohammed A. A. Al-qaness, Ahmed A. Ewees, Laith Abualigah, Mohamed Abd Elaziz, Rehab Ali Ibrahim, Mohammad H. Nadimi-Shahraki, Diego Oliva, Dalia Yousri, and Songfeng Lu
- Subjects
Soft computing ,Boosting (machine learning) ,Computer science ,General Mathematics ,Process (computing) ,soft computing ,Feature selection ,computer.software_genre ,metaheuristic (MH) ,Domain (software engineering) ,Set (abstract data type) ,feature selection (FS) ,machine learning ,Computer Science (miscellaneous) ,Orbit (dynamics) ,QA1-939 ,Data mining ,atomic orbital search (AOS) ,Engineering (miscellaneous) ,computer ,Metaheuristic ,Mathematics ,dynamic opposite-based learning (DOL) - Abstract
Feature selection (FS) is a well-known preprocess step in soft computing and machine learning algorithms. It plays a critical role in different real-world applications since it aims to determine the relevant features and remove other ones. This process (i.e., FS) reduces the time and space complexity of the learning technique used to handle the collected data. The feature selection methods based on metaheuristic (MH) techniques established their performance over all the conventional FS methods. So, in this paper, we presented a modified version of new MH techniques named Atomic Orbital Search (AOS) as FS technique. This is performed using the advances of dynamic opposite-based learning (DOL) strategy that is used to enhance the ability of AOS to explore the search domain. This is performed by increasing the diversity of the solutions during the searching process and updating the search domain. A set of eighteen datasets has been used to evaluate the efficiency of the developed FS approach, named AOSD, and the results of AOSD are compared with other MH methods. From the results, AOSD can reduce the number of features by preserving or increasing the classification accuracy better than other MH techniques.
- Published
- 2021
322. Three-Phase Feeder Load Balancing Based Optimized Neural Network Using Smart Meters
- Author
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Waled Merrji, Qosai Nawafleh, and Lina Alhmoud
- Subjects
Electric power distribution ,Physics and Astronomy (miscellaneous) ,Artificial neural network ,Computer science ,business.industry ,General Mathematics ,load balancing ,Load balancing (electrical power) ,Control reconfiguration ,artificial intelligence ,Smart grid ,Three-phase ,Chemistry (miscellaneous) ,Control theory ,Computer Science (miscellaneous) ,QA1-939 ,feed-forward back-propagation ,business ,MATLAB ,computer ,radial basis function ,Mathematics ,computer.programming_language - Abstract
The electricity distribution system is the coupling point between the utility and the end-user. Typically, these systems have unbalanced feeders due to the variety of customers’ behaviors. Some significant problems occur, the unbalanced loads increase the operational cost and system investment. In radial distribution systems, swapping loads between the three phases is the most effective method for phase balancing. It is performed manually and subjected to load flow equations, capacity, and voltage constraints. Recently, due to smart grids and automated networks, dynamic phase balancing received more attention, thus swapping the loads between the three phases automatically when unbalance exceeds permissible limits by using a remote-controlled phase switch selector/controller. Automatic feeder reconfiguration and phase balancing eliminates the service interruption, enhances energy restoration, and minimize losses. In this paper, a case study from the Irbid district electricity company (IDECO) is presented. Optimal reconfiguration of phase balancing using three techniques: feed-forward back-propagation neural network (FFBPNN), radial basis function neural network (RBFNN), and a hybrid are proposed to control the switching sequence for each connected load. The comparison shows that the hybrid technique yields the best performance. This work is simulated using MATLAB and C programming language.
- Published
- 2021
323. Snow Leopard Optimization Algorithm: A New Nature-Based Optimization Algorithm for Solving Optimization Problems
- Author
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Petr Coufal, Štěpán Hubálovský, Zoltan Balogh, and Marie Hubalovska
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Mathematical optimization ,Optimization problem ,Optimization algorithm ,Computer science ,General Mathematics ,nature-based algorithm ,Nature based ,optimization algorithm ,Global optimal ,Set (abstract data type) ,Computer Science (miscellaneous) ,QA1-939 ,snow leopard ,optimization problem ,Engineering (miscellaneous) ,optimization ,Mathematics - Abstract
Numerous optimization problems have been defined in different disciplines of science that must be optimized using effective techniques. Optimization algorithms are an effective and widely used method of solving optimization problems that are able to provide suitable solutions for optimization problems. In this paper, a new nature-based optimization algorithm called Snow Leopard Optimization Algorithm (SLOA) is designed that mimics the natural behaviors of snow leopards. SLOA is simulated in four phases including travel routes, hunting, reproduction, and mortality. The different phases of the proposed algorithm are described and then the mathematical modeling of the SLOA is presented in order to implement it on different optimization problems. A standard set of objective functions, including twenty-three functions, is used to evaluate the ability of the proposed algorithm to optimize and provide appropriate solutions for optimization problems. Also, the optimization results obtained from the proposed SLOA are compared with eight other well-known optimization algorithms. The optimization results show that the proposed SLOA has a high ability to solve various optimization problems. Also, the analysis and comparison of the optimization results obtained from the SLOA with the other eight algorithms shows that the SLOA is able to provide more appropriate quasi-optimal solutions and closer to the global optimal, and with better performance, it is much more competitive than similar algorithms.
- Published
- 2021
324. Analysis and Prediction for Confirmed COVID-19 Cases in Czech Republic with Uncertain Logistic Growth Model
- Author
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Wenjian Liu and Chunxiao Ding
- Subjects
Physics and Astronomy (miscellaneous) ,Partial residual plot ,uncertain hypothesis test ,General Mathematics ,COVID-19 ,Regression analysis ,uncertain statistics ,Confidence interval ,Term (time) ,uncertain regression model ,Normality test ,Chemistry (miscellaneous) ,Statistics ,Computer Science (miscellaneous) ,QA1-939 ,Logistic function ,Random variable ,uncertainty theory ,Mathematics ,Statistical hypothesis testing - Abstract
This paper presents an uncertain logistic growth model to analyse and predict the evolution of the cumulative number of COVID-19 infection in Czech Republic. Some fundamental knowledge about the uncertain regression analysis are reviewed firstly. Stochastic regression analysis is invalid to model cumulative number of confirmed COVID-19 cases in Czech Republic, by considering the disturbance term as random variables, because that the normality test and the identical distribution test of residuals are not passed, and the residual plot does not look like a null plot in the sense of probability theory. In this case, the uncertain logistic growth model is applied by characterizing the disturbance term as uncertain variables. Then parameter estimation, residual analysis, the forecast value and confidence interval are studied. Additionally, the uncertain hypothesis test is proposed to evaluate the appropriateness of the fitted logistic growth model and estimated disturbance term. The analysis and prediction for the cumulative number of COVID-19 infection in Czech Republic can propose theoretical support for the disease control and prevention. Due to the symmetry and similarity of epidemic transmission, other regions of COVID-19 infections, or other diseases can be disposed in a similar theory and method.
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- 2021
325. Existence Results of a Nonlocal Fractional Symmetric Hahn Integrodifference Boundary Value Problem
- Author
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Nichaphat Patanarapeelert, Thanin Sitthiwirattham, and Rujira Ouncharoen
- Subjects
Mathematics::Functional Analysis ,Physics and Astronomy (miscellaneous) ,boundary value problems ,General Mathematics ,existence ,Fixed-point theorem ,fixed point theorem ,Fixed point ,Computer Science::Digital Libraries ,Nonlinear system ,Operator (computer programming) ,fractional symmetric Hahn ,Fixed point problem ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,QA1-939 ,Applied mathematics ,Boundary value problem ,Mathematics - Abstract
The existence of solutions of nonlocal fractional symmetric Hahn integrodifference boundary value problem is studied. We propose a problem of five fractional symmetric Hahn difference operators and three fractional symmetric Hahn integrals of different orders. We first convert our nonlinear problem into a fixed point problem by considering a linear variant of the problem. When the fixed point operator is available, Banach and Schauder’s fixed point theorems are used to prove the existence results of our problem. Some properties of (q,ω)-integral are also presented in this paper as a tool for our calculations. Finally, an example is also constructed to illustrate the main results.
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- 2021
326. Weighted Second-Order Differential Inequality on Set of Compactly Supported Functions and Its Applications
- Author
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Ryskul Oinarov, Aigerim Kalybay, and Yaudat Sultanaev
- Subjects
Class (set theory) ,Nuclear operator ,Oscillation ,weighted inequality ,General Mathematics ,media_common.quotation_subject ,nuclear operator ,Zero (complex analysis) ,spectrum positive definiteness ,oscillation ,Infinity ,Differential operator ,Set (abstract data type) ,Computer Science (miscellaneous) ,QA1-939 ,Order (group theory) ,Applied mathematics ,fourth-order differential operator ,Engineering (miscellaneous) ,non-oscillation ,spectrum discreteness ,Mathematics ,media_common - Abstract
In the paper, we establish the oscillatory and spectral properties of a class of fourth-order differential operators in dependence on integral behavior of its coefficients at zero and infinity. In order to obtain these results, we investigate a certain weighted second-order differential inequality of independent interest.
- Published
- 2021
327. Optimality Conditions, Qualifications and Approximation Method for a Class of Non-Lipschitz Mathematical Programs with Switching Constraints
- Author
-
Jinman Lv, Zhongping Wan, and Zhenhua Peng
- Subjects
switching constraint ,Sequence ,Class (set theory) ,Mathematical optimization ,Computer science ,General Mathematics ,optimality condition ,non-Lipschitz ,stationary point ,Lipschitz continuity ,Stationary point ,Term (time) ,Constraint (information theory) ,Limit point ,Computer Science (miscellaneous) ,QA1-939 ,Engineering (miscellaneous) ,Mathematics - Abstract
In this paper, we consider a class of mathematical programs with switching constraints (MPSCs) where the objective involves a non-Lipschitz term. Due to the non-Lipschitz continuity of the objective function, the existing constraint qualifications for local Lipschitz MPSCs are invalid to ensure that necessary conditions hold at the local minimizer. Therefore, we propose some MPSC-tailored qualifications which are related to the constraints and the non-Lipschitz term to ensure that local minimizers satisfy the necessary optimality conditions. Moreover, we study the weak, Mordukhovich, Bouligand, strongly (W-, M-, B-, S-) stationay, analyze what qualifications making local minimizers satisfy the (M-, B-, S-) stationay, and discuss the relationship between the given MPSC-tailored qualifications. Finally, an approximation method for solving the non-Lipschitz MPSCs is given, and we show that the accumulation point of the sequence generated by the approximation method satisfies S-stationary under the second-order necessary condition and MPSC Mangasarian-Fromovitz (MF) qualification.
- Published
- 2021
328. Symmetry and Symmetry Breaking in Physics: From Geometry to Topology
- Author
-
Luciano Boi
- Subjects
Physics ,Quantum geometry ,Topological quantum field theory ,geometry ,topology ,Physics and Astronomy (miscellaneous) ,General Mathematics ,deformation ,Geometry ,dynamics ,Topology ,spacetime ,Symmetry (physics) ,Chemistry (miscellaneous) ,Homogeneous space ,Computer Science (miscellaneous) ,QA1-939 ,Symmetry breaking ,Mirror symmetry ,physics ,Topology (chemistry) ,Group theory ,breaking symmetry ,Mathematics ,symmetry - Abstract
Symmetry (and group theory) is a fundamental principle of theoretical physics. Finite symmetries, continuous symmetries of compact groups, and infinite-dimensional representations of noncompact Lie groups are at the core of solid physics, particle physics, and quantum physics, respectively. The latter groups now play an important role in many branches of mathematics. In more recent years, we have been faced with the impact of topological quantum field theory (TQFT). Topology and symmetry have deep connections, but topology is inherently broader and more complex. While the presence of symmetry in physical phenomena imposes strong constraints, topology seems to be related to low-energy states and is very likely to provide information about the different dynamical trajectories and patterns that particles can follow. For example, regarding the relationship of topology to low-energy states, Hodge’s theory of harmonic forms shows that the zero-energy states (for differential forms) correspond to the cohomology. Regarding the relationship of topology to particle trajectories, a topological knot can be seen as an orbit with complex properties in spacetime. The various deformations or embeddings of the knot, performed in low or high dimensions, allow defining different equivalence classes or topological types, and interestingly, it is possible from these types to study the symmetries associated with the deformations and their changes. More specifically, in the present work, we address two issues: first, that quantum geometry deforms classical geometry, and that this topological deformation may produce physical effects that are specific to the quantum physics scale, and second, that mirror symmetry and the phenomenon of topological change are closely related. This paper was aimed at understanding the conceptual and physical significance of this connection.
- Published
- 2021
329. Bayesian Inference under Small Sample Sizes Using General Noninformative Priors
- Author
-
Jingjing He, Min Huang, Xuefei Guan, Wei Wang, and Shaohua Wang
- Subjects
Computer science ,General Mathematics ,Bayesian probability ,Bayesian inference ,Invariant (physics) ,Conjugate prior ,Laplace's method ,invariant ,noninformative prior ,Jeffreys’ prior ,Prior probability ,Computer Science (miscellaneous) ,Range (statistics) ,QA1-939 ,Statistics::Methodology ,Engineering (miscellaneous) ,Algorithm ,Mathematics ,Jeffreys prior - Abstract
This paper proposes a Bayesian inference method for problems with small sample sizes. A general type of noninformative prior is proposed to formulate the Bayesian posterior. It is shown that this type of prior can represent a broad range of priors such as classical noninformative priors and asymptotically locally invariant priors and can be derived as the limiting states of normal-inverse-Gamma conjugate priors, allowing for analytical evaluations of Bayesian posteriors and predictors. The performance of different noninformative priors under small sample sizes is compared using the likelihood combining both fitting and prediction performances. Laplace approximation is used to evaluate the likelihood. A realistic fatigue reliability problem was used to illustrate the method. Following that, an actual aeroengine disk lifing application with two test samples is presented, and the results are compared with the existing method.
- Published
- 2021
330. Study on the Rotor Strength of High-Speed Permanent Magnet Motor Considering the Influence of Assembly Pressing Force
- Author
-
Shanshan Wang, Guo Weilin, Liyi Li, and Yusheng Hu
- Subjects
Pressing ,hot press assembly technology ,assembly pressing force ,rotor strength ,over-speed experiment ,Materials science ,Physics and Astronomy (miscellaneous) ,Rotor (electric) ,General Mathematics ,Process (computing) ,Mechanical engineering ,Interference (wave propagation) ,law.invention ,Chemistry (miscellaneous) ,Structural stability ,law ,Range (aeronautics) ,Magnet ,Computer Science (miscellaneous) ,QA1-939 ,Permanent magnet motor ,Mathematics - Abstract
In engineering application, the hot press assembly technology is often used to improve the stability of the rotor structure, but the conventional design methods cannot effectively evaluate the influence of this process on the rotor strength, which easily causes the rotor strength to exceed its safety margin range, and seriously it will lead to the failure of the rotor structure. This paper takes the cylindrical magnet surface-mounted high-speed permanent magnet synchronous motor rotor as the research object. Firstly, the influence of the assembly pressing force on the rotor stresses and interference is analyzed; then, comprehensively considering the assembly pressing force, speed and temperature, the rotor strength’s design method with high structural stability is proposed. Finally, based on the proposed method, the rotor strength of a 100 kW/30,000 rpm high-speed motor is designed, and the feasibility of the design is verified by over-speed experiment.
- Published
- 2021
331. Effect of Ventricular Elasticity Due to Congenital Hydrocephalus
- Author
-
Senthamilselvi Sathiamoorthy, Rifaqat Ali, Shyam Sundar Santra, Samad Noeiaghdam, Vediyappan Govindan, Hemalatha Balasundaram, and Aliona Dreglea
- Subjects
medicine.medical_specialty ,Physics and Astronomy (miscellaneous) ,Darcy number ,General Mathematics ,congenital hydrocephalus ,education ,fetal development ,resistance ,Cerebrospinal fluid ,Internal medicine ,Computer Science (miscellaneous) ,medicine ,QA1-939 ,Elasticity (economics) ,business.industry ,Biomechanics ,medicine.disease ,Compression (physics) ,Hydrocephalus ,Peclet number ,medicine.anatomical_structure ,Flow (mathematics) ,Chemistry (miscellaneous) ,Ventricle ,Cardiology ,elasticity ,Current (fluid) ,business ,Mathematics - Abstract
Cerebrospinal fluid (CSF) is a symmetric flow transport that surrounds brain and central nervous system (CNS). Congenital hydrocephalusis is an asymmetric and unusual cerebrospinal fluid flow during fetal development. This dumping impact enhances the elasticity over the ventricle wall. Henceforth, compression change influences the force of brain tissues. This paper presents a mathematical model to establish the effects of ventricular elasticity through a porous channel. The current model is good enough for immediate use by a neurosurgeon. The mathematical model is likely to be a powerful tool for the better treatment of hydrocephalus and other brain biomechanics. The non-linear dimensionless governing equations are solved using a perturbation technique, and the outcome is portrayed graphically with the aid of MATLAB.
- Published
- 2021
332. Supercyclic and Hypercyclic Generalized Weighted Backward Shifts over a Non-Archimedean <math display='inline'><semantics><mrow><msub><mi>c</mi><mn>0</mn></msub><mrow><mo>(</mo><mi mathvariant='double-struck'>N</mi><mo>)</mo></mrow></mrow></semantics></math> Space
- Author
-
Farrukh Mukhamedov, Abdessatar Souissi, and Otabek Khakimov
- Subjects
Pure mathematics ,non-Archimedean valuation ,General Mathematics ,Operator (physics) ,Triangular matrix ,MathematicsofComputing_GENERAL ,supercyclic operator ,Space (mathematics) ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,hypercylic operator ,generalized backward shift operator ,Computer Science (miscellaneous) ,QA1-939 ,Engineering (miscellaneous) ,Mathematics - Abstract
In the present paper, we propose to study generalized weighted backward shifts BB over non-Archimedean c0(N) spaces; here, B=(bij) is an upper triangular matrix with supi,j|bij|<∞. We investigate the sypercyclic and hypercyclic properties of BB. Furthermore, certain properties of the operator I+BB are studied as well. To establish the hypercyclic property of I+BB we have essentially used the non-Archimedeanity of the norm which leads to the difference between the real case.
- Published
- 2021
333. Optical Fiber Sensors for Monitoring Railway Infrastructures: A Review towards Smart Concept
- Author
-
Hua-Ping Wang, Ping Xiang, and Yung William Sasy Chan
- Subjects
Optical fiber ,Reflection (computer programming) ,Physics and Astronomy (miscellaneous) ,structural health monitoring ,Computer science ,General Mathematics ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Network configuration ,Optical fiber sensing ,law.invention ,Interference (communication) ,Chemistry (miscellaneous) ,law ,railway infrastructure ,industrialized optical fiber sensors ,Computer Science (miscellaneous) ,Systems engineering ,QA1-939 ,smart concept ,Structural health monitoring ,Sensitivity (control systems) ,strain transfer analysis ,Mathematics - Abstract
Railway infrastructures have played a critical role to ensure the continuity of goods and passenger transportation in China. Under extreme loading and environmental conditions, railway structures are vulnerable to deterioration and failure, leading to the interruption of the whole transportation system. Several techniques have been used for the health monitoring of railway structures. Optical fiber sensors are the widely recognized technique due to their inherent advantages such as high sensitivity, anti-electromagnetic interference, light weight, tiny size, corrosion resistance, and easy integration and network configuration. This paper provides a state-of-the-art of optical fiber sensing technologies and their practical application in railway infrastructures. In addition, the strain transfer analysis of optical fiber sensors is described for parameter reflection. A smart concept for artificial intelligence contribution is also declared. Finally, existing and future prospects on smart concept-based optical fiber sensors for railway infrastructure are discussed. The study can provide useful guidance to understand the problems in artificial intelligence which contributed to the Structural Health Monitoring system of railway structures.
- Published
- 2021
334. LRW-CRDB: Lossless Robust Watermarking Scheme for Categorical Relational Databases
- Author
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Chin-Chen Chang, Thai-Son Nguyen, and Chia-Chen Lin
- Subjects
Lossless compression ,Physics and Astronomy (miscellaneous) ,Relational database ,Computer science ,General Mathematics ,Data_MISCELLANEOUS ,Watermark ,blind ,robustness ,computer.software_genre ,lossless watermark ,Chemistry (miscellaneous) ,Robustness (computer science) ,relational database ,categorical data ,Information hiding ,Computer Science (miscellaneous) ,QA1-939 ,Embedding ,Data mining ,Categorical variable ,Digital watermarking ,computer ,Mathematics - Abstract
In 2002, Agrawal and Kiernan defined six basic requirements, including preventing illegal watermark embedding and authentication, reversibility, robustness, and others, which must be satisfied when a reversible watermark is designed for relational databases. To meet these requirements, in this paper, a lossless watermarking scheme for a categorical relational database called LRW-CRDB (lossless robust watermarking for categorical relational databases) is proposed. In our LRW-CRDB scheme, the database owner needs to generate two secret embedding keys, K1 and K2, in advance. Then, two reference sets are generated based on two different secret embedding keys and a symmetry-based data hiding strategy, and then these are used for the watermark embedding phases. Experimental results confirmed that our LRW-CRDB scheme successfully detects 100% of hidden watermarks, even when more than 95% of the watermarked relational database has been deleted. In other words, the robustness of our proposed LRW-CRDB scheme outperforms other existing schemes under a variety of possible attacks, such as alteration, sorting, deletion, and mix-match attacks.
- Published
- 2021
335. Slash Truncation Positive Normal Distribution and Its Estimation Based on the EM Algorithm
- Author
-
Diego I. Gallardo, Karol I. Santoro, and Héctor J. Gómez
- Subjects
Uniform distribution (continuous) ,Half-normal distribution ,Physics and Astronomy (miscellaneous) ,Estimation theory ,tpn package ,General Mathematics ,Normal distribution ,Slash distribution ,Chemistry (miscellaneous) ,slash distribution ,Expectation–maximization algorithm ,Computer Science (miscellaneous) ,Kurtosis ,QA1-939 ,Applied mathematics ,half-normal distribution ,Truncation (statistics) ,EM algorithm ,Mathematics - Abstract
In this paper, we present an extension of the truncated positive normal (TPN) distribution to model positive data with a high kurtosis. The new model is defined as the quotient between two random variables: the TPN distribution (numerator) and the power of a standard uniform distribution (denominator). The resulting model has greater kurtosis than the TPN distribution. We studied some properties of the distribution, such as moments, asymmetry, and kurtosis. Parameter estimation is based on the moments method, and maximum likelihood estimation uses the expectation-maximization algorithm. We performed some simulation studies to assess the recovery parameters and illustrate the model with a real data application related to body weight. The computational implementation of this work was included in the tpn package of the R software.
- Published
- 2021
336. Generalisation of the Frobenius Formula in the Theory of Block Operators on Normed Spaces
- Author
-
Denis Sidorov, Aliona Dreglea, and N. A. Sidorov
- Subjects
Pure mathematics ,Approximations of π ,General Mathematics ,Laurent series ,Fredholm operator ,Banach space ,Block (permutation group theory) ,Nekrasov–Nazarov method ,Operator theory ,System of linear equations ,Frobenius formula ,operator theory ,block operators ,asymptotic approximations ,Operator (computer programming) ,Computer Science (miscellaneous) ,QA1-939 ,Engineering (miscellaneous) ,Mathematics - Abstract
The efficient construction and employment of block operators are vital for contemporary computing, playing an essential role in various applications. In this paper, we prove a generalisation of the Frobenius formula in the setting of the theory of block operators on normed spaces. A system of linear equations with the block operator acting in Banach spaces is considered. Existence theorems are proved, and asymptotic approximations of solutions in regular and irregular cases are constructed. In the latter case, the solution is constructed in the form of a Laurent series. The theoretical approach is illustrated with an example, the construction of solutions for a block equation leading to a method of solving some linear integrodifferential system.
- Published
- 2021
337. Complex Dynamics of a Model with R&D Competition
- Author
-
Luca Guerrini, Mariangela Gangemi, Massimiliano Ferrara, and Tiziana Ciano
- Subjects
Hopf bifurcation ,Computer Science::Computer Science and Game Theory ,Physics and Astronomy (miscellaneous) ,Symmetric structure ,R&D ,General Mathematics ,TheoryofComputation_GENERAL ,time delay ,Stability (probability) ,hopf bifurcation ,R&D; time delay ,Competition (economics) ,Oligopoly ,symbols.namesake ,Complex dynamics ,Chemistry (miscellaneous) ,Nash equilibrium ,Computer Science (miscellaneous) ,symbols ,QA1-939 ,Applied mathematics ,Mathematics - Abstract
The paper analyzes a two-stage oligopoly game of semi-collusion in production described by a system with a symmetric structure. We examine the local stability of a Nash equilibrium and the presence of bifurcations. We discover that the model is capable of exhibiting extremely complicated dynamic behaviors.
- Published
- 2021
338. Online Activation and Deactivation of a Petri Net Supervisor
- Author
-
Zied Hajej, Nidhal Rezg, and Sadok Rezig
- Subjects
Supervisor ,theory of regions ,Physics and Astronomy (miscellaneous) ,Computer science ,General Mathematics ,Distributed computing ,Flexible manufacturing system ,supervisory control ,Petri net ,flexible manufacturing system ,Supervisory control ,Chemistry (miscellaneous) ,Reachability ,Control theory ,Computer Science (miscellaneous) ,QA1-939 ,Graph (abstract data type) ,activation ,State (computer science) ,discrete event system ,deactivation ,Mathematics - Abstract
This paper highlights algebraic and mathematical properties in symmetry with Petri nets in order to control automated systems such as flexible workshops, which represent one of the most important examples in industry and for discrete event systems in general. This project deals with the problem of forbidden state transition by using a new application of the theory of regions for supervisory control. In the literature, most control synthesis methods suffer greatly from a cumbersome calculation burden of the Petri net supervisor given the complex exploration of the state graph. Our new methodology lightens the computational load of the Petri net supervisor by choosing specific regions on the reachability graph, on which the control is calculated offline using CPLEX. The determined controller is activated online if the process enters the chosen region, and deactivated otherwise. All our experiments were applied in a flexible workshop implemented in our research laboratory, which was used to engrave selected models on glass blocks of different colors.
- Published
- 2021
339. Contact-Complex Riemannian Submersions
- Author
-
Erol Kılıç, Şemsi Eken Meriç, and Cornelia-Livia Bejan
- Subjects
Pure mathematics ,Riemannian submersion ,General Mathematics ,MathematicsofComputing_GENERAL ,law.invention ,symbols.namesake ,law ,Computer Science (miscellaneous) ,QA1-939 ,Hermitian manifold ,submanifold ,Einstein ,Mathematics::Symplectic Geometry ,Engineering (miscellaneous) ,Mathematics ,almost-contact metric manifold ,Ricci soliton ,Mathematics::Complex Variables ,Riemannian manifold ,Base (topology) ,Submanifold ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,Metric (mathematics) ,symbols ,Computer Science::Programming Languages ,Mathematics::Differential Geometry ,Manifold (fluid mechanics) - Abstract
A submersion from an almost contact Riemannian manifold to an almost Hermitian manifold, acting on the horizontal distribution by preserving both the metric and the structure, is, roughly speaking a contact-complex Riemannian submersion. This paper deals mainly with a contact-complex Riemannian submersion from an η-Ricci soliton; it studies when the base manifold is Einstein on one side and when the fibres are η-Einstein submanifolds on the other side. Some results concerning the potential are also obtained here.
- Published
- 2021
340. An Efficient and Robust Improved A* Algorithm for Path Planning
- Author
-
He Hongqi, Xuyan Qi, Shangjie Lou, Jing Jing, Liu Wei, and Huanwei Wang
- Subjects
Mathematical optimization ,Physics and Astronomy (miscellaneous) ,Bidirectional search ,Computer science ,General Mathematics ,expansion distance ,A* search algorithm ,bidirectional search ,smoothing ,path planning ,A* algorithm ,heuristic function ,Mobile robot navigation ,law.invention ,Chemistry (miscellaneous) ,law ,Robustness (computer science) ,Algorithmic efficiency ,Path (graph theory) ,Computer Science (miscellaneous) ,QA1-939 ,Motion planning ,Smoothing ,Mathematics - Abstract
Path planning plays an essential role in mobile robot navigation, and the A* algorithm is one of the best-known path planning algorithms. However, the conventional A* algorithm and the subsequent improved algorithms still have some limitations in terms of robustness and efficiency. These limitations include slow algorithm efficiency, weak robustness, and collisions when robots are traversing. In this paper, we propose an improved A*-based algorithm called EBHSA* algorithm. The EBHSA* algorithm introduces the expansion distance, bidirectional search, heuristic function optimization and smoothing into path planning. The expansion distance extends a certain distance from obstacles to improve path robustness by avoiding collisions. Bidirectional search is a strategy that searches for a path from the start node and from the goal node at the same time. Heuristic function optimization designs a new heuristic function to replace the traditional heuristic function. Smoothing improves path robustness by reducing the number of right-angle turns. Moreover, we carry out simulation tests with the EBHSA* algorithm, and the test results show that the EBHSA* algorithm has excellent performance in terms of robustness and efficiency. In addition, we transplant the EBHSA* algorithm to a robot to verify its effectiveness in the real world.
- Published
- 2021
341. Approximate Noether Symmetries of Perturbed Lagrangians and Approximate Conservation Laws
- Author
-
Matteo Gorgone and Francesco Oliveri
- Subjects
approximate Lie symmetries ,Conservation law ,Differential equation ,General Mathematics ,approximate Noether theorem ,State (functional analysis) ,perturbed Lagrangians ,approximate conservation laws ,symbols.namesake ,Homogeneous space ,Computer Science (miscellaneous) ,symbols ,QA1-939 ,Noether's theorem ,Engineering (miscellaneous) ,Approximate conservation laws ,Approximate Lie symmetries ,Approximate Noether theorem ,Perturbed Lagrangians ,Mathematics ,Mathematical physics - Abstract
In this paper, within the framework of the consistent approach recently introduced for approximate Lie symmetries of differential equations, we consider approximate Noether symmetries of variational problems involving small terms. Then, we state an approximate Noether theorem leading to the construction of approximate conservation laws. Some illustrative applications are presented.
- Published
- 2021
342. Multifeature Detection of Microaneurysms Based on Improved SSA
- Author
-
Jiazhong Xu, Liwei Deng, and Xiaofei Wang
- Subjects
Connected component ,Microaneurysm ,diabetic retina ,Physics and Astronomy (miscellaneous) ,Radon transform ,business.industry ,Computer science ,General Mathematics ,Binary image ,CPU time ,Pattern recognition ,connection components ,Chemistry (miscellaneous) ,asymmetric microaneurysm ,Computer Science (miscellaneous) ,QA1-939 ,Preprocessor ,Noise (video) ,Artificial intelligence ,Cluster analysis ,business ,SSA ,Mathematics - Abstract
The early diagnosis of retinopathy is crucial to the prevention and treatment of diabetic retinopathy. The low proportion of positive cases in the asymmetric microaneurysm detection problem causes preprocessing to treat microaneurysms as noise to be eliminated. To obtain a binary image containing microaneurysms, the object was segmented by a symmetry algorithm, which is a combination of the connected components and SSA methods. Next, a candidate microaneurysm set was extracted by multifeature clustering of binary images. Finally, the candidate microaneurysms were mapped to the Radon frequency domain to achieve microaneurysm detection. In order to verify the feasibility of the algorithm, a comparative experiment was conducted on the combination of the connected components and SSA methods. In addition, PSNR, FSIM, SSIM, fitness value, average CPU time and other indicators were used as evaluation standards. The results showed that the overall performance of the binary image obtained by the algorithm was the best. Last but not least, the accuracy of the detection method for microaneurysms in this paper reached up to 93.24%, which was better than that of several classic microaneurysm detection methods in the same period.
- Published
- 2021
343. {0,1}-Brauer Configuration Algebras and Their Applications in Graph Energy Theory
- Author
-
Agustín Moreno Cañadas, Pedro Fernando Fernández Espinosa, Natalia Agudelo Muñetón, and Isaías David Marín Gaviria
- Subjects
spectral radius ,graph energy ,Spectral radius ,General Mathematics ,trace norm ,Contrast (statistics) ,Digraph ,Computer Science::Digital Libraries ,Combinatorics ,Singular value ,Graph energy ,brauer configuration algebra ,path algebra ,poset ,wild representation type ,Computer Science (miscellaneous) ,QA1-939 ,Computer Science::Programming Languages ,Adjacency matrix ,Partially ordered set ,Engineering (miscellaneous) ,Energy (signal processing) ,Mathematics - Abstract
The energy E(G) of a graph G is the sum of the absolute values of its adjacency matrix. In contrast, the trace norm of a digraph Q, which is the sum of the singular values of the corresponding adjacency matrix, is the oriented version of the energy of a graph. It is worth pointing out that one of the main problems in this theory consists of determining appropriated bounds of these types of energies for significant classes of graphs, digraphs and matrices, provided that, in general, finding out their exact values is a problem of great difficulty. In this paper, the trace norm of a {0,1}-Brauer configuration is introduced. It is estimated and computed by associating suitable families of graphs and posets to Brauer configuration algebras.
- Published
- 2021
344. A Soft-YoloV4 for High-Performance Head Detection and Counting
- Author
-
Zhen Zhang, Shaoning Zeng, Shihao Xia, Yuxing Cai, and Cuimei Yang
- Subjects
Computer science ,business.industry ,General Mathematics ,YoloV4 ,soft-NMS ,NMS ,Robustness (computer science) ,head detection ,people counting ,Computer Science (miscellaneous) ,QA1-939 ,Head (vessel) ,Computer vision ,Artificial intelligence ,Detection rate ,business ,Engineering (miscellaneous) ,Mathematics - Abstract
Blockage of pedestrians will cause inaccurate people counting, and people’s heads are easily blocked by each other in crowded occasions. To reduce missed detections as much as possible and improve the capability of the detection model, this paper proposes a new people counting method, named Soft-YoloV4, by attenuating the score of adjacent detection frames to prevent the occurrence of missed detection. The proposed Soft-YoloV4 improves the accuracy of people counting and reduces the incorrect elimination of the detection frames when heads are blocked by each other. Compared with the state-of-the-art YoloV4, the AP value of the proposed head detection method is increased from 88.52 to 90.54%. The Soft-YoloV4 model has much higher robustness and a lower missed detection rate for head detection, and therefore it dramatically improves the accuracy of people counting.
- Published
- 2021
345. On the Fekete–Szegö Problem for Meromorphic Functions Associated with p,q-Wright Type Hypergeometric Function
- Author
-
Adriana Cătaş
- Subjects
Pure mathematics ,Physics and Astronomy (miscellaneous) ,Mathematics::Complex Variables ,General Mathematics ,Field (mathematics) ,Function (mathematics) ,Fekete–Szegö problem ,p,q-Wright type hypergeometric function ,Type (model theory) ,Differential operator ,Wright ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,QA1-939 ,Computer Science::Programming Languages ,meromorphic functions ,Hypergeometric function ,p,q-derivative operator ,Mathematics ,Analytic function ,Meromorphic function - Abstract
Making use of a post-quantum derivative operator, we define two classes of meromorphic analytic functions. For the considered family of functions, we aim to investigate the sharp bounds’ values in the case of the Fekete–Szegö problem. The study of the well-known Fekete–Szegö functional in the post-quantum calculus case for meromorphic functions provides new outcomes for research in the field. With the extended p,q-operator, we establish certain inequalities’ relations concerning meromorphic functions. In the final part of the paper, a new p,q-analogue of the q-Wright type hypergeometric function is introduced. This function generalizes the classical and symmetrical Gauss hypergeometric function. All the obtained results are sharp.
- Published
- 2021
346. Separate Fractional (p,q)-Integrodifference Equations via Nonlocal Fractional (p,q)-Integral Boundary Conditions
- Author
-
Sotiris K. Ntouyas, Thongchai Dumrongpokaphan, and Thanin Sitthiwirattham
- Subjects
nonlocal boundary value problems ,Physics and Astronomy (miscellaneous) ,General Mathematics ,Mathematical analysis ,MathematicsofComputing_GENERAL ,existence ,Nonlinear system ,Operator (computer programming) ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,QA1-939 ,Boundary value problem ,Uniqueness ,fractional (p,q)-integral ,Mathematics ,fractional (p,q)-difference - Abstract
In this paper, we study a boundary value problem involving (p,q)-integrodifference equations, supplemented with nonlocal fractional (p,q)-integral boundary conditions with respect to asymmetric operators. First, we convert the given nonlinear problem into a fixed-point problem, by considering a linear variant of the problem at hand. Once the fixed-point operator is available, existence and uniqueness results are established using the classical Banach’s and Schaefer’s fixed-point theorems. The application of the main results is demonstrated by presenting numerical examples. Moreover, we study some properties of (p,q)-integral that are used in our study.
- Published
- 2021
347. New Irregular Solutions in the Spatially Distributed Fermi–Pasta–Ulam Problem
- Author
-
Sergey Kashchenko and Anna Tolbey
- Subjects
Spatial variable ,Physics ,Basis (linear algebra) ,General Mathematics ,Mathematical analysis ,Structure (category theory) ,Fermi–Pasta–Ulam problem ,Differential operator ,quasinormal forms ,special distributed chains ,Nonlinear system ,symbols.namesake ,asymptotics ,Computer Science (miscellaneous) ,symbols ,QA1-939 ,Engineering (miscellaneous) ,Schrödinger's cat ,Mathematics - Abstract
For the spatially-distributed Fermi–Pasta–Ulam (FPU) equation, irregular solutions are studied that contain components rapidly oscillating in the spatial variable, with different asymptotically large modes. The main result of this paper is the construction of families of special nonlinear systems of the Schrödinger type—quasinormal forms—whose nonlocal dynamics determines the local behavior of solutions to the original problem, as t→∞. On their basis, results are obtained on the asymptotics in the main solution of the FPU equation and on the interaction of waves moving in opposite directions. The problem of “perturbing” the number of N elements of a chain is considered. In this case, instead of the differential operator, with respect to one spatial variable, a special differential operator, with respect to two spatial variables appears. This leads to a complication of the structure of an irregular solution.
- Published
- 2021
348. Machine Learning Techniques Applied to Predict Tropospheric Ozone in a Semi-Arid Climate Region
- Author
-
Suhail Mahmud, Al Masum Bhuiyan, Ramanjit K. Sahi, and Romyull Islam
- Subjects
Ozone ,General Mathematics ,Decision tree ,semi-arid climate ,Machine learning ,computer.software_genre ,Wind speed ,chemistry.chemical_compound ,Naive Bayes classifier ,Computer Science (miscellaneous) ,QA1-939 ,Tropospheric ozone ,Engineering (miscellaneous) ,NOx ,tropospheric ozone ,business.industry ,Stochastic gradient descent ,machine learning ,chemistry ,Environmental science ,Nitrogen oxide ,Artificial intelligence ,business ,computer ,Mathematics ,El Paso-Juarez - Abstract
In the last decade, ground-level ozone exposure has led to a significant increase in environmental and health risks. Thus, it is essential to measure and monitor atmospheric ozone concentration levels. Specifically, recent improvements in machine learning (ML) processes, based on statistical modeling, have provided a better approach to solving these risks. In this study, we compare Naive Bayes, K-Nearest Neighbors, Decision Tree, Stochastic Gradient Descent, and Extreme Gradient Boosting (XGBoost) algorithms and their ensemble technique to classify ground-level ozone concentration in the El Paso-Juarez area. As El Paso-Juarez is a non-attainment city, the concentrations of several air pollutants and meteorological parameters were analyzed. We found that the ensemble (soft voting classifier) of algorithms used in this paper provide high classification accuracy (94.55%) for the ozone dataset. Furthermore, variables that are highly responsible for the high ozone concentration such as Nitrogen Oxide (NOx), Wind Speed and Gust, and Solar radiation have been discovered.
- Published
- 2021
349. The Predictive Power of Transition Matrices
- Author
-
André Berchtold
- Subjects
Mathematical optimization ,predictive power ,measure of association ,Physics and Astronomy (miscellaneous) ,Markov chain ,Computer science ,General Mathematics ,Lag ,Stochastic matrix ,Chemistry (miscellaneous) ,Computer Science (miscellaneous) ,Parameterized complexity ,transition matrix ,Measure (mathematics) ,Variable (computer science) ,Order (exchange) ,Predictive power ,QA1-939 ,Mathematics ,MTD model - Abstract
When working with Markov chains, especially if they are of order greater than one, it is often necessary to evaluate the respective contribution of each lag of the variable under study on the present. This is particularly true when using the Mixture Transition Distribution model to approximate the true fully parameterized Markov chain. Even if it is possible to evaluate each transition matrix using a standard association measure, these measures do not allow taking into account all the available information. Therefore, in this paper, we introduce a new class of so-called "predictive power" measures for transition matrices. These measures address the shortcomings of traditional association measures, so as to allow better estimation of high-order models.
- Published
- 2021
350. Fixed-Time Synchronization of Neural Networks Based on Quantized Intermittent Control for Image Protection
- Author
-
Jinyue Yang, Wenqiang Yang, Li Xiao, and Junjian Huang
- Subjects
Artificial neural network ,Computer science ,business.industry ,Settling time ,General Mathematics ,Intermittent control ,fixed-time synchronization ,Encryption ,quantized intermittent control ,image protection ,neural networks ,Image (mathematics) ,Control theory ,Fixed time ,Synchronization (computer science) ,Computer Science (miscellaneous) ,QA1-939 ,business ,Engineering (miscellaneous) ,Mathematics - Abstract
This paper considers the fixed-time synchronization (FIXTS) of neural networks (NNs) by using quantized intermittent control (QIC). Based on QIC, a fixed-time controller is designed to ensure that the NNs achieve synchronization in finite time. With this controller, the settling time can be estimated regardless of initial conditions. After ensuring that the system has stabilized through this strategy, it is suitable for image protection given the behavior of the system. Meanwhile, the encryption effect of the image depends on the encryption algorithm, and the quality of the decrypted image depends on the synchronization error of NNs. The numerical results show that the designed controller is effective and validate the practical application of FIXTS of NNs in image protection.
- Published
- 2021
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