Symmetry

15 pages, 291 KiB

Open AccessArticle

On a Certain Subclass of Analytic Functions Defined by Touchard Polynomials

by Bolenini Venkateswarlu, Pinninti Thirupathi Reddy, Şahsene Altınkaya, Nattakan Boonsatit, Porpattama Hammachukiattikul and Vaishnavy Sujatha

Symmetry 2022, 14(4), 838; https://doi.org/10.3390/sym14040838 - 18 Apr 2022

Cited by 4 | Viewed by 2362

Abstract

This paper focuses on the establishment of a new subfamily of analytic functions including Touchard polynomials. Then, we attempt to obtain geometric properties such as coefficient inequalities, distortion properties, extreme points, radii of starlikeness and convexity, partial sums, neighbourhood results and integral means’ [...] Read more.

This paper focuses on the establishment of a new subfamily of analytic functions including Touchard polynomials. Then, we attempt to obtain geometric properties such as coefficient inequalities, distortion properties, extreme points, radii of starlikeness and convexity, partial sums, neighbourhood results and integral means’ inequality for this class. The symmetry properties of the subfamily of functions established in the current paper may be examined as future research directions. Full article

(This article belongs to the Special Issue Symmetry in Pure Mathematics and Real and Complex Analysis)

17 pages, 554 KiB

Open AccessArticle

Reliability Estimation for Stress-Strength Model Based on Unit-Half-Normal Distribution

by Rolando de la Cruz, Hugo S. Salinas and Cristian Meza

Symmetry 2022, 14(4), 837; https://doi.org/10.3390/sym14040837 - 18 Apr 2022

Cited by 13 | Viewed by 3040

Abstract

Many lifetime distribution models have successfully served as population models for risk analysis and reliability mechanisms. We propose a novel estimation procedure of stress–strength reliability in the case of two independent unit-half-normal distributions can fit asymmetrical data with either positive or negative skew, [...] Read more.

Many lifetime distribution models have successfully served as population models for risk analysis and reliability mechanisms. We propose a novel estimation procedure of stress–strength reliability in the case of two independent unit-half-normal distributions can fit asymmetrical data with either positive or negative skew, with different shape parameters. We obtain the maximum likelihood estimator of the reliability, its asymptotic distribution, and exact and asymptotic confidence intervals. In addition, confidence intervals of model parameters are constructed by using bootstrap techniques. We study the performance of the estimators based on Monte Carlo simulations, the mean squared error, average bias and length, and coverage probabilities. Finally, we apply the proposed reliability model in data analysis of burr measurements on the iron sheets. Full article

(This article belongs to the Special Issue Symmetric and Asymmetric Distributions: Theoretical Developments and Applications Ⅲ)

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16 pages, 835 KiB

Open AccessArticle

Hadamard–Mercer, Dragomir–Agarwal–Mercer, and Pachpatte–Mercer Type Fractional Inclusions for Convex Functions with an Exponential Kernel and Their Applications

by Soubhagya Kumar Sahoo, Ravi P. Agarwal, Pshtiwan Othman Mohammed, Bibhakar Kodamasingh, Kamsing Nonlaopon and Khadijah M. Abualnaja

Symmetry 2022, 14(4), 836; https://doi.org/10.3390/sym14040836 - 18 Apr 2022

Cited by 12 | Viewed by 1844

Abstract

Many scholars have recently become interested in establishing integral inequalities using various known fractional operators. Fractional calculus has grown in popularity as a result of its capacity to quickly solve real-world problems. First, we establish new fractional inequalities of the Hadamard–Mercer, Pachpatte–Mercer, and [...] Read more.

Many scholars have recently become interested in establishing integral inequalities using various known fractional operators. Fractional calculus has grown in popularity as a result of its capacity to quickly solve real-world problems. First, we establish new fractional inequalities of the Hadamard–Mercer, Pachpatte–Mercer, and Dragomir–Agarwal–Mercer types containing an exponential kernel. In this regard, the inequality proved by Jensen and Mercer plays a major role in our main results. Integral inequalities involving convexity have a wide range of applications in several domains of mathematics where symmetry is important. Both convexity and symmetry are closely linked with each other; when working on one of the topics, you can apply what you have learned to the other. We consider a new identity for differentiable mappings and present its companion bound for the Dragomir–Agarwal–Mercer type inequality employing a convex function. Applications involving matrices are presented. Finally, we conclude our article and discuss its future scope. Full article

(This article belongs to the Special Issue Symmetry in Fractional Calculus and Inequalities)

10 pages, 777 KiB

Open AccessArticle

A Generalization of Group-Graded Modules

by Mohammed Al-Shomrani and Najlaa Al-Subaie

Symmetry 2022, 14(4), 835; https://doi.org/10.3390/sym14040835 - 18 Apr 2022

Cited by 2 | Viewed by 1812

Abstract

In this article, we generalize the concept of group-graded modules by introducing the concept of

G

-weak graded R-modules, which are R-modules graded by a set

G

of left coset representatives, where R is a

G

-weak graded ring. Moreover, we [...] Read more.

In this article, we generalize the concept of group-graded modules by introducing the concept of

G

-weak graded R-modules, which are R-modules graded by a set

G

of left coset representatives, where R is a

G

-weak graded ring. Moreover, we prove some properties of these modules. Finally, results related to

G

-weak graded fields and their vector spaces are deduced. Many considerable examples are provided with more emphasis on the symmetric group

S_{3}

and the dihedral group

D_{6}

, which gives the group of symmetries of a regular hexagon. Full article

(This article belongs to the Special Issue Recent Advances in the Application of Symmetry Group)

16 pages, 3932 KiB

Open AccessArticle

Self-Frequency Shift in Transmission of Asymmetric Pulse in Optical Medium

by Yusheng Zhang, Lin Huang, Bin Zhang, Daru Chen and Yudong Cui

Symmetry 2022, 14(4), 834; https://doi.org/10.3390/sym14040834 - 18 Apr 2022

Cited by 2 | Viewed by 2152

Abstract

Linear and nonlinear effects often induce a pulse self-frequency shift as it propagates along with an optical medium. Here, we theoretically investigate the transmission dynamics of asymmetric pulses propagating along with an optical medium in the temporal and spectral domains. Due to the [...] Read more.

Linear and nonlinear effects often induce a pulse self-frequency shift as it propagates along with an optical medium. Here, we theoretically investigate the transmission dynamics of asymmetric pulses propagating along with an optical medium in the temporal and spectral domains. Due to the asymmetric nonlinear phase-shift effect in the optical medium, the peak wavelength of asymmetric pulses exhibits a redshift or a blueshift in the spectral domain, while it slows down or speeds up in the temporal domain. Our results show that the peak wavelength shift initiated by a temporal or spectral asymmetric pulse depends not only on the pulse intensity, but also on the initial pulse chirp and dispersion of optical medium. We find that the peak wavelength shift of the asymmetric pulse increases with the pulse intensity and the initial pulse chirp, together with the spectrum width. The temporal and frequency shifts of the asymmetric pulses are found to be sensitive to the asymmetry ratio as well. These excellent properties may lead to the realization of a self-frequency shift-based tunable light source by launching asymmetric pulses into an optical medium. Full article

(This article belongs to the Section Physics)

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11 pages, 348 KiB

Open AccessArticle

Brain Functional Connectivity Asymmetry: Left Hemisphere Is More Modular

by Lucia Jajcay, David Tomeček, Jiří Horáček, Filip Španiel and Jaroslav Hlinka

Symmetry 2022, 14(4), 833; https://doi.org/10.3390/sym14040833 - 18 Apr 2022

Cited by 5 | Viewed by 3540

Abstract

Graph-theoretical approaches are increasingly used to study the brain and may enhance our understanding of its asymmetries. In this paper, we hypothesize that the structure of the left hemisphere is, on average, more modular. To this end, we analyzed resting-state functional magnetic resonance [...] Read more.

Graph-theoretical approaches are increasingly used to study the brain and may enhance our understanding of its asymmetries. In this paper, we hypothesize that the structure of the left hemisphere is, on average, more modular. To this end, we analyzed resting-state functional magnetic resonance imaging data of 90 healthy subjects. We computed functional connectivity by Pearson’s correlation coefficient, turned the matrix into an unweighted graph by keeping a certain percentage of the strongest connections, and quantified modularity separately for the subgraph formed by each hemisphere. Our results show that the left hemisphere is more modular. The result is consistent across a range of binarization thresholds, regardless of whether the two hemispheres are thresholded together or separately. This illustrates that graph-theoretical analysis can provide a robust characterization of lateralization of brain functional connectivity. Full article

(This article belongs to the Special Issue The Study of Brain Asymmetry)

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17 pages, 2906 KiB

Open AccessArticle

A Multi-Objective Cellular Memetic Optimization Algorithm for Green Scheduling in Flexible Job Shops

by Yong Wang, Wange Peng, Chao Lu and Huan Xia

Symmetry 2022, 14(4), 832; https://doi.org/10.3390/sym14040832 - 18 Apr 2022

Cited by 8 | Viewed by 2171

Abstract

In the last 30 years, a flexible job shop scheduling problem (FJSP) has been extensively explored. Production efficiency is a widely utilized objective. With the rise in environmental awareness, green objectives (e.g., energy consumption) have received a lot of attention. Nevertheless, energy consumption [...] Read more.

In the last 30 years, a flexible job shop scheduling problem (FJSP) has been extensively explored. Production efficiency is a widely utilized objective. With the rise in environmental awareness, green objectives (e.g., energy consumption) have received a lot of attention. Nevertheless, energy consumption has received little attention. Furthermore, controllable processing times (CPT) should be considered in the field of scheduling, because they are closer to some real production. Therefore, this work investigates a FJSP with CPT (i.e., FJSP-CPT) where asymmetrical conditions and symmetrical constraints increase the difficulty of problem solving. The objectives of FJSP-CPT are to minimize simultaneously the maximum completion time (i.e., makespan) and total energy consumption (TEC). First of all, a mathematical model of this multi-objective FJSP-CPT was formulated. To optimize this problem, a novel multi-objective cellular memetic optimization algorithm (MOCMOA) was presented. The proposed MOMOA combined the advantages of cellular structure for global exploration and variable neighborhood search (VNS) for local exploitation. At last, MOCMOA was compared against other multi-objective optimization approaches by performing experiments. Numerical experiments reveal that the presented MOCMOA is superior to its competitors in 15 instances regarding three commonly used performance metrics. Full article

(This article belongs to the Section Computer)

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18 pages, 6920 KiB

Open AccessArticle

Dynamic Behavior of the Inertial Platform Related to the Research Facility Building Laser and Gamma at ELI-NP Bucharest

by Polidor Bratu, Adrian Mihai Goanta, Nicusor Dragan, Sorin Vlase, Calin Itu, George Lucian Nicolae and Samir Iacovescu

Symmetry 2022, 14(4), 831; https://doi.org/10.3390/sym14040831 - 17 Apr 2022

Cited by 2 | Viewed by 1702

Abstract

This paper aims to study the vibration of the large inertial platform from the Laser + Gamma building that is part of the ELI-NP project. In order to ensure a precisely positioned radiation beam, it is necessary that the shocks and vibrations coming [...] Read more.

This paper aims to study the vibration of the large inertial platform from the Laser + Gamma building that is part of the ELI-NP project. In order to ensure a precisely positioned radiation beam, it is necessary that the shocks and vibrations coming from the external environment are damped or absorbed until they reach the work installations. This is ensured by the platform on which the devices are positioned, a platform that is supported on spring batteries and shock absorbers. A rigid body model is developed in this regard and a comparison with the finite element model of the concrete platform is conducted. It has been found that low vibration modes can be obtained with the help of the rigid model, which also has the advantage of simplicity and very little time is required to obtain results. Full article

(This article belongs to the Special Issue Symmetry in Theoretical and Applied Mechanics)

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24 pages, 5902 KiB

Open AccessArticle

Optimal Design for a Bivariate Step-Stress Accelerated Life Test with Alpha Power Exponential Distribution Based on Type-I Progressive Censored Samples

by Refah Alotaibi, Aned Al Mutairi, Ehab M. Almetwally, Chanseok Park and Hoda Rezk

Symmetry 2022, 14(4), 830; https://doi.org/10.3390/sym14040830 - 16 Apr 2022

Cited by 13 | Viewed by 2091

Abstract

We consider an optimization design for the alpha power exponential (APE) distribution as asymmetrical probability distributions under progressive type-I censoring for a step-stress accelerated life test. In this study, two stress variables are taken into account. To save the time and cost of [...] Read more.

We consider an optimization design for the alpha power exponential (APE) distribution as asymmetrical probability distributions under progressive type-I censoring for a step-stress accelerated life test. In this study, two stress variables are taken into account. To save the time and cost of lifetime testing, progressive censoring and accelerated life testing are utilized. The test units’ lifespans are supposed to follow an APE distribution. A cumulative exposure model is used to study the impact of varying stress levels. A log-linear relationship between the APE distribution’s scale parameter and stress is postulated. The maximum likelihood estimators, Bayesian estimators of the model parameters based on the symmetric loss function, approximate confidence intervals (CIs) and credible intervals are provided. Under normal operating conditions, an ideal test plan is designed by minimizing the asymptotic variance of the percentile life. Full article

(This article belongs to the Section Mathematics)

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15 pages, 9768 KiB

Open AccessArticle

Quasi-Reflective Chaotic Mutant Whale Swarm Optimization Fused with Operators of Fish Aggregating Device

by Shoubao Su, Chao He and Liukai Xu

Symmetry 2022, 14(4), 829; https://doi.org/10.3390/sym14040829 - 15 Apr 2022

Cited by 1 | Viewed by 2475

Abstract

To improve the performance of the whale optimization algorithm and further enhance the search accuracy, while increasing the convergence speed, a quasi-reflective chaotic mutant whale swarm optimization, namely QNWOA, is proposed, fused with an operator of Fish Aggregating Devices (FADs) in this paper. [...] Read more.

To improve the performance of the whale optimization algorithm and further enhance the search accuracy, while increasing the convergence speed, a quasi-reflective chaotic mutant whale swarm optimization, namely QNWOA, is proposed, fused with an operator of Fish Aggregating Devices (FADs) in this paper. Firstly, the swarm diversity is increased by using logistic chaotic mapping. Secondly, a quasi-reflective learning mechanism is introduced to improve the convergence speed of the algorithm. Then, the FADs vortex effect and wavelet variation of the marine predator algorithm (MPA) are introduced in the search phase to enhance the stability of the algorithm in the early and late stages and the ability to escape from the local optimum by broking the symmetry of iterative routes. Finally, a combination of linearly decreasing and nonlinear segmentation convergence factors is proposed to balance the local and global search capabilities of the algorithm. Nine benchmark functions are selected for the simulation, and after comparing with other algorithms, the results show that the convergence speed and solution accuracy of the proposed algorithm are promising in this study. Full article

(This article belongs to the Special Issue Meta-Heuristics for Manufacturing Systems Optimization)

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15 pages, 3925 KiB

Open AccessArticle

A Large Payload Data Hiding Scheme Using Scalable Secret Reference Matrix

by Jason Lin, Chia-Wei Tsai, Chun-Wei Yang and Kuan-Hung Liu

Symmetry 2022, 14(4), 828; https://doi.org/10.3390/sym14040828 - 15 Apr 2022

Cited by 3 | Viewed by 2200

Abstract

When imperceptibility is an issue, data-hiding techniques typically become limited to small payloads. In this paper, a novel data-hiding scheme is proposed that allows embedding large payloads while maintaining high stego-image quality. The scheme utilizes an

N \times N

sub-block for constructing a [...] Read more.

When imperceptibility is an issue, data-hiding techniques typically become limited to small payloads. In this paper, a novel data-hiding scheme is proposed that allows embedding large payloads while maintaining high stego-image quality. The scheme utilizes an

N \times N

sub-block for constructing a reference matrix as a secret key that allows the symmetric embedding and extraction of secret data from a grayscale cover image, where

N

is a positive integer greater than or equal to two. With proper modification, the proposed method can be directly converted to a symmetric cryptosystem. For cases with acceptable stego-image quality (i.e., PSNR > 34), the experimental results showed that the proposed method can embed, on average, four bits per pixel (bpp), a higher hiding capacity than in previous works, and also offers the ability to adjust the capacity by varying

N

. The number of solutions for a sub-block reaches the factorial of

N^{2}

, guaranteeing the security of data embedding and extraction. In addition, the proposed method has low computational complexity and can be implemented in a straightforward manner. Full article

(This article belongs to the Special Issue Information Security and Cryptology: Advanced Technologies in Symmetry/Asymmetry)

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17 pages, 713 KiB

Open AccessArticle

The Functional Expansion Approach for Solving NPDEs as a Generalization of the Kudryashov and G^′/G Methods

by Carmen Ionescu, Corina N. Babalic, Radu Constantinescu and Raluca Efrem

Symmetry 2022, 14(4), 827; https://doi.org/10.3390/sym14040827 - 15 Apr 2022

Cited by 5 | Viewed by 1936

Abstract

This paper presents the functional expansion approach as a generalized method for finding traveling wave solutions of various nonlinear partial differential equations. The approach can be seen as a combination of the Kudryashov and

G^{'} / G

solving methods. It allowed the [...] Read more.

This paper presents the functional expansion approach as a generalized method for finding traveling wave solutions of various nonlinear partial differential equations. The approach can be seen as a combination of the Kudryashov and

G^{'} / G

solving methods. It allowed the extension of the first method to the use of second order auxiliary equations, and, at the same time, it allowed non-standard

G^{'} / G

-solutions to be generated. The functional expansion is illustrated here on the Dodd–Bullough–Mikhailov model, using a linear second order ordinary differential equation as an auxiliary equation. Full article

(This article belongs to the Special Issue Advances in Nonlinear Dynamics and Symmetry)

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17 pages, 556 KiB

Open AccessArticle

Asymmetric Probability Mass Function for Count Data Based on the Binomial Technique: Synthesis and Analysis with Inference

by Afrah Al-Bossly and Mohamed S. Eliwa

Symmetry 2022, 14(4), 826; https://doi.org/10.3390/sym14040826 - 15 Apr 2022

Cited by 2 | Viewed by 1831

Abstract

In this article, a new probability mass function for count data is proposed based on the binomial technique. After introducing the methodology of the newly model, some of its distributional characteristics are discussed in-detail. It is found that the newly model has explicit [...] Read more.

In this article, a new probability mass function for count data is proposed based on the binomial technique. After introducing the methodology of the newly model, some of its distributional characteristics are discussed in-detail. It is found that the newly model has explicit mathematical expressions for its statistical and reliability properties, which is not the case with many well-known discrete models. Moreover, it can be used as an effectively probability tool for modeling asymmetric over-dispersed data with leptokurtic shapes. The parameters estimation through the classical point of view have been done via utilizing the technique of maximum likelihood and Bayesian approaches. A MCMC simulation study is carried out to examine the performance of the estimators. Finally, two distinct real data sets are analyzed to prove the flexibility and notability of the newly model. Full article

(This article belongs to the Section Mathematics)

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28 pages, 9666 KiB

Open AccessArticle

Analysis of Position, Pose and Force Decoupling Characteristics of a 4-UPS/1-RPS Parallel Grinding Robot

by Jun Wang, Fei Liang, Hongjun Zhou, Mingquan Yang and Quan Wang

Symmetry 2022, 14(4), 825; https://doi.org/10.3390/sym14040825 - 14 Apr 2022

Cited by 74 | Viewed by 2813

Abstract

For the application of parallel robots in the grinding industry, a parallel robot equipped with a constant force actuator that produces a constant force for grinding is designed. To study the characteristics of the parallel robot’s spatial positions and poses, the inverse solutions [...] Read more.

For the application of parallel robots in the grinding industry, a parallel robot equipped with a constant force actuator that produces a constant force for grinding is designed. To study the characteristics of the parallel robot’s spatial positions and poses, the inverse solutions of the moving platform’s spatial positions and poses as well as the workspace where objects were ground were established by using DH parameters and geometric methods. The experimental results showed that the workspace where objects were ground was a cylinder with a cross section similar to a symmetric circular sector. To analyze the characteristics of the forces produced by the parallel robotic system, the dynamics equation was established via the Newton–Euler method to verify the rationality of the force decoupling design. Theoretical calculation combined with simulation and experimental analyses confirmed the viability of the theoretical analyses which lay a theoretical foundation for the design, manufacture and control of the parallel robotic system proposed in this paper. Full article

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11 pages, 2106 KiB

Open AccessArticle

Prediction of Large Second Harmonic Generation in the Metal-Oxide/Organic Hybrid Compound CuMoO₃(p2c)

by Tingting Yang, Xueli Huang, Xiyue Cheng, Paul A. Maggard, Myung-Hwan Whangbo, Chengkai Luan and Shuiquan Deng

Symmetry 2022, 14(4), 824; https://doi.org/10.3390/sym14040824 - 14 Apr 2022

Cited by 1 | Viewed by 2301

Abstract

Noncentrosymmetric hybrid framework (HF) materials are an important system in discovering new practical second-order nonlinear optical materials. We calculated the second harmonic generation (SHG) response of a noncentrosymmetric (NCS) organic–inorganic HF compound, CuMoO₃(p2c) (p2c = pyrazine-2-carboxylate) to find that it exhibits [...] Read more.

Noncentrosymmetric hybrid framework (HF) materials are an important system in discovering new practical second-order nonlinear optical materials. We calculated the second harmonic generation (SHG) response of a noncentrosymmetric (NCS) organic–inorganic HF compound, CuMoO₃(p2c) (p2c = pyrazine-2-carboxylate) to find that it exhibits the largest SHG response among all known NCS HF materials with one-dimensional helical chains. Further atom response theory analysis revealed that the metal atoms Cu and Mo contribute much more strongly than do nonmetal atoms in determining the strength of the SHG response, which is a novel example in nonlinear optical materials known to date. Full article

(This article belongs to the Section Chemistry: Symmetry/Asymmetry)

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28 pages, 10517 KiB

Open AccessArticle

Scalable Post-Processing of Large-Scale Numerical Simulations of Turbulent Fluid Flows

by Christian Lagares, Wilson Rivera and Guillermo Araya

Symmetry 2022, 14(4), 823; https://doi.org/10.3390/sym14040823 - 14 Apr 2022

Cited by 6 | Viewed by 2320

Abstract

Military, space, and high-speed civilian applications will continue contributing to the renewed interest in compressible, high-speed turbulent boundary layers. To further complicate matters, these flows present complex computational challenges ranging from the pre-processing to the execution and subsequent post-processing of large-scale numerical simulations. [...] Read more.

Military, space, and high-speed civilian applications will continue contributing to the renewed interest in compressible, high-speed turbulent boundary layers. To further complicate matters, these flows present complex computational challenges ranging from the pre-processing to the execution and subsequent post-processing of large-scale numerical simulations. Exploring more complex geometries at higher Reynolds numbers will demand scalable post-processing. Modern times have brought application developers and scientists the advent of increasingly more diversified and heterogeneous computing hardware, which significantly complicates the development of performance-portable applications. To address these challenges, we propose Aquila, a distributed, out-of-core, performance-portable post-processing library for large-scale simulations. It is designed to alleviate the burden of domain experts writing applications targeted at heterogeneous, high-performance computers with strong scaling performance. We provide two implementations, in C++ and Python; and demonstrate their strong scaling performance and ability to reach 60% of peak memory bandwidth and 98% of the peak filesystem bandwidth while operating out of core. We also present our approach to optimizing two-point correlations by exploiting symmetry in the Fourier space. A key distinction in the proposed design is the inclusion of an out-of-core data pre-fetcher to give the illusion of in-memory availability of files yielding up to 46% improvement in program runtime. Furthermore, we demonstrate a parallel efficiency greater than 70% for highly threaded workloads. Full article

(This article belongs to the Special Issue Turbulence and Multiphase Flows and Symmetry)

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19 pages, 6858 KiB

Open AccessArticle

The Symmetry and Topology of Finite and Periodic Graphs and Their Embeddings in Three-Dimensional Euclidean Space

by Michael O’Keeffe and Michael M. J. Treacy

Symmetry 2022, 14(4), 822; https://doi.org/10.3390/sym14040822 - 14 Apr 2022

Cited by 10 | Viewed by 3447

Abstract

We make the case for the universal use of the Hermann-Mauguin (international) notation for the description of rigid-body symmetries in Euclidean space. We emphasize the importance of distinguishing between graphs and their embeddings and provide examples of 0-, 1-, 2-, and 3-periodic structures. [...] Read more.

We make the case for the universal use of the Hermann-Mauguin (international) notation for the description of rigid-body symmetries in Euclidean space. We emphasize the importance of distinguishing between graphs and their embeddings and provide examples of 0-, 1-, 2-, and 3-periodic structures. Embeddings of graphs are given as piecewise linear with finite, non-intersecting edges. We call attention to problems of conflicting terminology when disciplines such as materials chemistry and mathematics collide. Full article

(This article belongs to the Special Issue Symmetry in Discrete and Combinatorial Geometry)

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17 pages, 4100 KiB

Open AccessReview

Authentication Securing Methods for Mobile Identity: Issues, Solutions and Challenges

by Zuriati Ahmad Zukarnain, Amgad Muneer and Mohd Khairulanuar Ab Aziz

Symmetry 2022, 14(4), 821; https://doi.org/10.3390/sym14040821 - 14 Apr 2022

Cited by 16 | Viewed by 5855

Abstract

Smartphone devices have become an essential part of our daily activities for performing various essential applications containing very confidential information. For this reason, the security of the device and the transactions is required to ensure that the transactions are performed legally. Most regular [...] Read more.

Smartphone devices have become an essential part of our daily activities for performing various essential applications containing very confidential information. For this reason, the security of the device and the transactions is required to ensure that the transactions are performed legally. Most regular mobile users’ authentication methods used are passwords and short messages. However, numerous security vulnerabilities are inherent in various authentication schemes. Fingerprint identification and face recognition technology sparked a massive wave of adoption a few years back. The international mobile equipment identity (IMEI) and identity-based public key cryptography (ID-based PKC) have also become widely used options. More complex methods have been introduced, such as the management flow that combines transaction key creation, encryption, and decryption in processing users’ personal information and biometric features. There is also a combination of multiple user-based authentications, such as user’s trip routes initialization with the coordinates of home and office to set template trajectories and stay points for authentication. Therefore, this research aimed to identify the issues with the available authentication methods and the best authentication solution while overcoming the challenges. Full article

(This article belongs to the Special Issue Information Technologies and Electronics Ⅱ)

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14 pages, 2750 KiB

Open AccessArticle

Automatic Classification of Equivalent Mutants in Mutation Testing of Android Applications

by Muhammad Bello Kusharki, Sanjay Misra, Bilkisu Muhammad-Bello, Ibrahim Anka Salihu and Bharti Suri

Symmetry 2022, 14(4), 820; https://doi.org/10.3390/sym14040820 - 14 Apr 2022

Cited by 7 | Viewed by 2767

Abstract

Software and symmetric testing methodologies are primarily used in detecting software defects, but these testing methodologies need to be optimized to mitigate the wasting of resources. As mobile applications are becoming more prevalent in recent times, the need to have mobile applications that [...] Read more.

Software and symmetric testing methodologies are primarily used in detecting software defects, but these testing methodologies need to be optimized to mitigate the wasting of resources. As mobile applications are becoming more prevalent in recent times, the need to have mobile applications that satisfy software quality through testing cannot be overemphasized. Testing suites and software quality assurance techniques have also become prevalent, which underscores the need to evaluate the efficacy of these tools in the testing of the applications. Mutation testing is one such technique, which is the process of injecting small changes into the software under test (SUT), thereby creating mutants. These mutants are then tested using mutation testing techniques alongside the SUT to determine the effectiveness of test suites through mutation scoring. Although mutation testing is effective, the cost of implementing it, due to the problem of equivalent mutants, is very high. Many research works gave varying solutions to this problem, but none used a standardized dataset. In this research work, we employed a standard mutant dataset tool called MutantBench to generate our data. Subsequently, an Abstract Syntax Tree (AST) was used in conjunction with a tree-based convolutional neural network (TBCNN) as our deep learning model to automate the classification of the equivalent mutants to reduce the cost of mutation testing in software testing of android applications. The result shows that the proposed model produces a good accuracy rate of 94%, as well as other performance metrics such as recall (96%), precision (89%), F1-score (92%), and Matthew’s correlation coefficients (88%) with fewer False Negatives and False Positives during testing, which is significant as it implies that there is a decrease in the risk of misclassification. Full article

(This article belongs to the Special Issue Recent Advances in Software for Symmetry)

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17 pages, 3796 KiB

Open AccessArticle

Asymmetric Orientation Combination for Reversible and Authenticable Data Hiding of Dual Stego-images

by Jiang-Yi Lin, Ji-Hwei Horng, Chin-Chen Chang and Yung-Hui Li

Symmetry 2022, 14(4), 819; https://doi.org/10.3390/sym14040819 - 14 Apr 2022

Cited by 6 | Viewed by 1992

Abstract

A dual-image-based reversible data hiding (RDH) scheme can conceal secret data into a cover image by creating two steganographic images. These two stego-images can cooperate to extract secret data and restore the cover image. This paper describes a generalization of the orientation combination [...] Read more.

A dual-image-based reversible data hiding (RDH) scheme can conceal secret data into a cover image by creating two steganographic images. These two stego-images can cooperate to extract secret data and restore the cover image. This paper describes a generalization of the orientation combination technology for dual-image-based RDH. We first propose a full search algorithm to find the optimal set of the reversible orientation combinations. Based on the algorithm, the modification range of pixel values can be dynamically enlarged, and thus the embedding capacity becomes adjustable. In addition, an authentication algorithm is provided to detect tampered shadows based on a faithful one. Experimental results confirm that the proposed scheme can produce dual stego-images with a good visual quality. Furthermore, our method provides an adjustable payload. A lot more secret data can be embedded than with state-of-the-art methods, with a satisfactory image quality. Two steganalysis tools are applied to demonstrate the security level of the proposed scheme. Full article

(This article belongs to the Special Issue Symmetric and Asymmetric Encryption in Blockchain)

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22 pages, 804 KiB

Open AccessArticle

Suitable Mass Density Function for an Artificial Satellite to Prevent Chaotic Motion after Collision with Space Debris

by Lotfi Hidri, Mehdi Mrad and Mohammed Alkahtani

Symmetry 2022, 14(4), 818; https://doi.org/10.3390/sym14040818 - 14 Apr 2022

Cited by 1 | Viewed by 1773

Abstract

Artificial satellites are widely used in different areas such as communication, position systems, and agriculture. The number of satellites orbiting Earth is becoming huge, and many are set to be launched soon. This huge number of satellites in addition to space debris are [...] Read more.

Artificial satellites are widely used in different areas such as communication, position systems, and agriculture. The number of satellites orbiting Earth is becoming huge, and many are set to be launched soon. This huge number of satellites in addition to space debris are sources of concern. Indeed, some incidents have occurred either between satellites or because of space debris. These incidents are a threat for the hit satellite and can be a source of irreversible damages. A hit satellite may diverge to a chaotic motion with all the entailed consequences. The inertia moment of a satellite is a main factor to determine if the hit satellite is heading toward a chaotic motion or not. The inertia moment is determined over the mass density function. In this paper, a circularly orbiting artificial satellite was modeled as a thin rotating rod. The objective was to determine a suitable mass density function for this satellite allowing the prevention as much as possible of the chaotic motion after being hit. This unknown density mass function satisfies a system of equations reflecting some physical constraints. Conventional procedures are not applicable to solve this system of equations. The presented resolution method is based on several mathematical transformations, allowing converting this system into a highly nonlinear one with several unknowns. Several mathematical techniques were applied, and an analytical solution was obtained. Finally, from the mechanical engineering point of view, the obtained mass density function corresponds to a Functionally Graded Material (FGM). Full article

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11 pages, 311 KiB

Open AccessArticle

Stochastic Finite-Time Stability for Stochastic Nonlinear Systems with Stochastic Impulses

by Wei Hu

Symmetry 2022, 14(4), 817; https://doi.org/10.3390/sym14040817 - 14 Apr 2022

Cited by 6 | Viewed by 1993

Abstract

In this paper, some novel stochastic finite-time stability criteria for stochastic nonlinear systems with stochastic impulse effects are established. The results in this paper blackgeneralized the related results in from two aspects: 1. the model in is the deterministic systems, which means that [...] Read more.

In this paper, some novel stochastic finite-time stability criteria for stochastic nonlinear systems with stochastic impulse effects are established. The results in this paper blackgeneralized the related results in from two aspects: 1. the model in is the deterministic systems, which means that the noise effect that can be described as a symmetric Markov process Brownian motion is considered in our models; 2. the stochastic finite-time stability criterion is established in this paper, not the asymptotic stability and the input-to-state stability that are studied in the form literature. Finally, an example is given to show the significance blackand usefulness of our results. Full article

(This article belongs to the Special Issue Advanced Symmetry Methods for Dynamics, Control, Optimization and Applications)

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15 pages, 1087 KiB

Open AccessArticle

Pancyclicity of the n-Generalized Prism over Skirted Graphs

by Artchariya Muaengwaeng, Ratinan Boonklurb and Sirirat Singhun

Symmetry 2022, 14(4), 816; https://doi.org/10.3390/sym14040816 - 14 Apr 2022

Cited by 1 | Viewed by 1576

Abstract

A side skirt is a planar rooted tree T,

T \neq P_{2}

, where the root of T is a vertex of degree at least two, and all other vertices except the leaves are of degree at least three. A reduced [...] Read more.

A side skirt is a planar rooted tree T,

T \neq P_{2}

, where the root of T is a vertex of degree at least two, and all other vertices except the leaves are of degree at least three. A reduced Halin graph or a skirted graph is a plane graph

G = T \cup P

, where T is a side skirt, and P is a path connecting the leaves of T in the order determined by the embedding of T. The structure of reduced Halin or skirted graphs contains both symmetry and asymmetry. For

n \geq 2

and

P_{n} = v_{1} v_{2} v_{3} \dots v_{n}

as a path of length

n - 1

, we call the Cartesian product of a graph G and a path

P_{n}

, the n-generalized prism over a graph G. We have known that the n-generalized prism over a skirted graph is Hamiltonian. To support the Bondy’s metaconjecture from 1971, we show that the n-generalized prism over a skirted graph is pancyclic. Full article

(This article belongs to the Special Issue Graph Algorithms and Graph Theory)

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14 pages, 272 KiB

Open AccessArticle

Bipolar Fuzzy Set Theory Applied to the Certain Ideals in BCI-Algebras

by N. Abughazalah, G. Muhiuddin, Mohamed E. A. Elnair and A. Mahboob

Symmetry 2022, 14(4), 815; https://doi.org/10.3390/sym14040815 - 14 Apr 2022

Cited by 6 | Viewed by 1828

Abstract

The study of symmetry is one of the most important and beautiful themes uniting various areas of contemporary arithmetic. Algebraic structures are useful structures in pure mathematics for learning a geometrical object’s symmetries. In this paper, we introduce new concepts in an algebraic [...] Read more.

The study of symmetry is one of the most important and beautiful themes uniting various areas of contemporary arithmetic. Algebraic structures are useful structures in pure mathematics for learning a geometrical object’s symmetries. In this paper, we introduce new concepts in an algebraic structure called BCI-algebra, where we present the concepts of bipolar fuzzy (closed) BCI-positive implicative ideals and bipolar fuzzy (closed) BCI-commutative ideals of BCI-algebras. The relationship between bipolar fuzzy (closed) BCI-positive implicative ideals and bipolar fuzzy ideals is investigated, and various conditions are provided for a bipolar fuzzy ideal to be a bipolar fuzzy BCI-positive implicative ideal. Furthermore, conditions are presented for a bipolar fuzzy (closed) ideal to be a bipolar fuzzy BCI-commutative ideal. Full article

(This article belongs to the Special Issue The Study of Lattice Theory and Universal Algebra)

76 pages, 4149 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Cerebral Polymorphisms for Lateralisation: Modelling the Genetic and Phenotypic Architectures of Multiple Functional Modules

by Chris McManus

Symmetry 2022, 14(4), 814; https://doi.org/10.3390/sym14040814 - 14 Apr 2022

Cited by 19 | Viewed by 14738

Abstract

Recent fMRI and fTCD studies have found that functional modules for aspects of language, praxis, and visuo-spatial functioning, while typically left, left and right hemispheric respectively, frequently show atypical lateralisation. Studies with increasing numbers of modules and participants are finding increasing numbers of [...] Read more.

Recent fMRI and fTCD studies have found that functional modules for aspects of language, praxis, and visuo-spatial functioning, while typically left, left and right hemispheric respectively, frequently show atypical lateralisation. Studies with increasing numbers of modules and participants are finding increasing numbers of module combinations, which here are termed cerebral polymorphisms—qualitatively different lateral organisations of cognitive functions. Polymorphisms are more frequent in left-handers than right-handers, but it is far from the case that right-handers all show the lateral organisation of modules described in introductory textbooks. In computational terms, this paper extends the original, monogenic McManus DC (dextral-chance) model of handedness and language dominance to multiple functional modules, and to a polygenic DC model compatible with the molecular genetics of handedness, and with the biology of visceral asymmetries found in primary ciliary dyskinesia. Distributions of cerebral polymorphisms are calculated for families and twins, and consequences and implications of cerebral polymorphisms are explored for explaining aphasia due to cerebral damage, as well as possible talents and deficits arising from atypical inter- and intra-hemispheric modular connections. The model is set in the broader context of the testing of psychological theories, of issues of laterality measurement, of mutation-selection balance, and the evolution of brain and visceral asymmetries. Full article

(This article belongs to the Special Issue Cognitive and Neurophysiological Models of Brain Asymmetry)

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16 pages, 3320 KiB

Open AccessArticle

Evaluation of the Dynamic Impact of a Passing Vehicle on a Bridge Deck Due to a Damaged Expansion Joint

by Jing Gao, Xintao Zhang and Jiayan Lei

Symmetry 2022, 14(4), 813; https://doi.org/10.3390/sym14040813 - 14 Apr 2022

Cited by 2 | Viewed by 2062

Abstract

When a vehicle passes over a bridge, it may jump on the bridge due to a damaged expansion joint. The sudden jump induces a heavy dynamic impact on the bridge and therefore damages the bridge deck and girder. The traditional dynamic amplification factor [...] Read more.

When a vehicle passes over a bridge, it may jump on the bridge due to a damaged expansion joint. The sudden jump induces a heavy dynamic impact on the bridge and therefore damages the bridge deck and girder. The traditional dynamic amplification factor defined by the current bridge design code shows the amplification of the static effects on the bridge. However, it only concerns the stable moving load induced by the vehicle. The sudden vehicle impact due to a damaged expansion joint sometimes exceeds the allowable design load, so it is important to evaluate the dynamic impact in practice. In fact, the dynamic impact can be approximately considered as a contact force between a damped harmonic oscillator and a beam due to the bilateral symmetry of the vehicle; therefore, a model-based approach using the bridge midspan acceleration is proposed in this study to approximately evaluate the impact force, where it is assumed as an exponentially damped sine function. This is a typical parametric model-based inverse problem. The conjugate direction method is used to determine the unknown parameters and the initial values are determined by a simple global search method. Since only five parameters are included, the proposed method is simpler than the conventional basis function-based methods. Numerical simulations were conducted to validate the proposed method. Generally, the proposed method performs well to identify the dynamic impact. In particular, the displacement measured directly from the bridge is preferred since the displacement obtained from the acceleration has numerical errors; the measurement noise in the range of 1% to 5% shows a slight influence on the proposed method; and the error of frequencies and mode shapes greatly affects the proposed method, especially for the maximum force. Full article

(This article belongs to the Special Issue Symmetry in Safety and Disaster Prevention Engineering)

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20 pages, 3724 KiB

Open AccessFeature PaperReview

Galactic Anomalies and Particle Dark Matter

by Malcolm Fairbairn

Symmetry 2022, 14(4), 812; https://doi.org/10.3390/sym14040812 - 14 Apr 2022

Cited by 4 | Viewed by 4645

Abstract

This is a brief review of aspects of galactic astrophysics and astronomy which have a possible bearing on particle dark matter. It is still quite normal for particle physicists to try to solve “well known anomalies“ that are apparently seen in observations of [...] Read more.

This is a brief review of aspects of galactic astrophysics and astronomy which have a possible bearing on particle dark matter. It is still quite normal for particle physicists to try to solve “well known anomalies“ that are apparently seen in observations of galaxies (missing satellites, cusp vs. core, etc.) whereas a lot of these anomalies have actually been resolved many years ago. We will try to briefly review the field and discuss many of the areas in question. Full article

(This article belongs to the Special Issue Symmetry, Dark Matter and the Characterisation of Its Properties)

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12 pages, 1336 KiB

Open AccessArticle

Influence of an External Classical Field on a ♢ Four-Level Atom Inside a Quantized Field

by Eied Mahmoud Khalil, Hanaa Abu-Zinadah and Mahmoud Youssef Abd-Rabbou

Symmetry 2022, 14(4), 811; https://doi.org/10.3390/sym14040811 - 14 Apr 2022

Cited by 8 | Viewed by 1782

Abstract

In this paper, we study the effect of detuning parameters and driven external classical field parameters on a quantum system consisting of a ♢-configuration four-level atom inside a quantized cavity field. Under some canonical conditional of dressed states, the exact solution of the [...] Read more.

In this paper, we study the effect of detuning parameters and driven external classical field parameters on a quantum system consisting of a ♢-configuration four-level atom inside a quantized cavity field. Under some canonical conditional of dressed states, the exact solution of the Schrödinger equation is obtained. The occupation of atomic levels and statistical population inversion is studied. Our results show that the classical field parameter dissolved the collapse periods and increased the maximum bounds of the upper state, while decreasing the lower bounds of the lower state. The detuning parameters reduce the minimum bounds of atomic levels and their inversion. On the other hand, the linear entropy and

l_{1}

norm of coherence are employed to measure the temporal evolution of the mixedness and coherence. It is found that the driven classical field improves the temporal evolution of the mixedness and lower bounds of coherence. However, the detuning parameters have a destructive effect on the mixedness and lower bounds of coherence. The intensity of the external classical field is regarded as a control parameter with different values of detuning parameters. Full article

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12 pages, 1419 KiB

Open AccessArticle

Perceptual Hash of Neural Networks

by Zhiying Zhu, Hang Zhou, Siyuan Xing, Zhenxing Qian, Sheng Li and Xinpeng Zhang

Symmetry 2022, 14(4), 810; https://doi.org/10.3390/sym14040810 - 13 Apr 2022

Cited by 2 | Viewed by 2815

Abstract

In recent years, advances in deep learning have boosted the practical development, distribution and implementation of deep neural networks (DNNs). The concept of symmetry is often adopted in a deep neural network to construct an efficient network structure tailored for a specific task, [...] Read more.

In recent years, advances in deep learning have boosted the practical development, distribution and implementation of deep neural networks (DNNs). The concept of symmetry is often adopted in a deep neural network to construct an efficient network structure tailored for a specific task, such as the classic encoder-decoder structure. Massive DNN models are diverse in category, quantity and open source frameworks for implementation. Therefore, the retrieval of DNN models has become a problem worthy of attention. To this end, we propose a new idea of generating perceptual hashes of DNN models, named HNN-Net (Hash Neural Network), to index similar DNN models by similar hash codes. The proposed HNN-Net is based on neural graph networks consisting of two stages: the graph generator and the graph hashing. In the graph generator stage, the target DNN model is first converted and optimized into a graph. Then, it is assigned with additional information extracted from the execution of the original model. In the graph hashing stage, it learns to construct a compact binary hash code. The constructed hash function can well preserve the features of both the topology structure and the semantics information of a neural network model. Experimental results demonstrate that the proposed scheme is effective to represent a neural network with a short hash code, and it is generalizable and efficient on different models. Full article

(This article belongs to the Special Issue Security, Communication and Privacy in Internet of Things: Symmetry and Advances)

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14 pages, 788 KiB

Open AccessFeature PaperArticle

Determining Ground-State Phase Diagrams on Quantum Computers via a Generalized Application of Adiabatic State Preparation

by Akhil Francis, Ephrata Zelleke, Ziyue Zhang, Alexander F. Kemper and James K. Freericks

Symmetry 2022, 14(4), 809; https://doi.org/10.3390/sym14040809 - 13 Apr 2022

Cited by 9 | Viewed by 2166

Abstract

Quantum phase transitions materialize as level crossings in the ground-state energy when the parameters of the Hamiltonian are varied. The resulting ground-state phase diagrams are straightforward to determine by exact diagonalization on classical computers, but are challenging on quantum computers because of the [...] Read more.

Quantum phase transitions materialize as level crossings in the ground-state energy when the parameters of the Hamiltonian are varied. The resulting ground-state phase diagrams are straightforward to determine by exact diagonalization on classical computers, but are challenging on quantum computers because of the accuracy needed and the near degeneracy of the competing states close to the level crossings. On the other hand, classical computers are limited to small system sizes, which quantum computers may help overcome. In this work, we use a local adiabatic ramp for state preparation to allow us to directly compute ground-state phase diagrams on a quantum computer via time evolution. This methodology is illustrated by examining the ground states of the XY model with a magnetic field in the z-direction in one dimension. We are able to calculate an accurate phase diagram on both two- and three-site systems using IBM quantum machines. Full article

(This article belongs to the Section Physics)

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