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Symmetry, Volume 11, Issue 12 (December 2019)

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Open AccessArticle
Numerical Investigation of Aligned Magnetic Flow Comprising Nanoliquid over a Radial Stretchable Surface with Cattaneo–Christov Heat Flux with Entropy Generation
Symmetry 2019, 11(12), 1520; https://doi.org/10.3390/sym11121520 (registering DOI) - 15 Dec 2019
Abstract
The influence of entropy generation on aligned magnetic flow-including nanoparticles through a convectively heated radial stretched surface in the existence of Cattaneo–Christov heat flux is inspected. The highly nonlinear leading PDE’s via the similar scaling transformation are developed. The resulting system via the [...] Read more.
The influence of entropy generation on aligned magnetic flow-including nanoparticles through a convectively heated radial stretched surface in the existence of Cattaneo–Christov heat flux is inspected. The highly nonlinear leading PDE’s via the similar scaling transformation are developed. The resulting system via the bvp4c technique from Matlab is computed. The impacts of rising constraints on the liquid velocity, nanoparticles concentration and temperature profile are argued and showed via portraits and table. In addition, the performance of liquid flow is inspected through the friction factor, the mass and heat transfer rate. With the rise in the thermal relaxation constraint, the thermal boundary layer is appreciably altered. Due to an aligned angle, the velocity of nanoliquid declines, while the concentration and temperature of nanofluid augment. It is also observed that the values of friction factor increase, whereas the values of heat and mass transfer decline due to an aligned angle. Entropy generation profiles developed due to magnetic parameters and the aligned angle. Lastly, a comparative scrutiny is composed via the previous studies which lead to support for our presently developed model. Full article
(This article belongs to the Special Issue Symmetry in Newtonian and Non-Newtonian Fluids)
Open AccessArticle
Nonlinear Consensus Protocol Modified from Doubly Stochastic Quadratic Operators in Networks of Dynamic Agents
Symmetry 2019, 11(12), 1519; https://doi.org/10.3390/sym11121519 (registering DOI) - 15 Dec 2019
Abstract
This article explores nonlinear convergence to limit the effects of the consensus problem that usually occurs in multi-agent systems. Most of the existing research essentially considers the outline of linear protocols, using complex mathematical equations in various orders. In this work, however, we [...] Read more.
This article explores nonlinear convergence to limit the effects of the consensus problem that usually occurs in multi-agent systems. Most of the existing research essentially considers the outline of linear protocols, using complex mathematical equations in various orders. In this work, however, we designed and developed an alternative nonlinear protocol based on simple and effective mathematical approaches. The designed protocol in this sense was modified from the Doubly Stochastic Quadratic Operators (DSQO) and was aimed at resolving consensus problems. Therefore, we called it Modified Doubly Stochastic Quadratic Operators (MDSQO). The protocol was derived in the context of coordinated systems to overcome the consensus issue related to multi-agent systems. In the process, we proved that by using the proposed nonlinear protocol, the consensus could be reached via a common agreement among the agents (average consensus) in a fast and easy fashion without losing any initial status. Moreover, the investigated nonlinear protocol of MDSQO realized the reaching consensus always as well as DSQO in some cases, which could not reach consensus. Finally, simulation results were given to prove the validity of the theoretical analysis. Full article
Open AccessArticle
Automatic Defect Inspection for Coated Eyeglass Based on Symmetrized Energy Analysis of Color Channels
Symmetry 2019, 11(12), 1518; https://doi.org/10.3390/sym11121518 (registering DOI) - 15 Dec 2019
Abstract
Nowadays, eyeglassesare used for vision correction as well as in the fashion industry. Eyeglasses have become more expensive and the eyewear industry has grown rapidly, thereby requiring the development of advanced coating technologies. However, defect detection by visual inspection in the manufacturing process [...] Read more.
Nowadays, eyeglassesare used for vision correction as well as in the fashion industry. Eyeglasses have become more expensive and the eyewear industry has grown rapidly, thereby requiring the development of advanced coating technologies. However, defect detection by visual inspection in the manufacturing process of eyeglass coatings is difficult. To solve this problem, we propose the coated eyeglass defect detection system framework based on machine vision for real-time inspection. First, we locate and extract regions of interest (ROI) ofthe coated eyeglass by adopting cross-projection based on symmetrizedenergy analysis. Next, we propose an efficient method based on the symmetrized energy analysis of color channelsto enhance defectsin each color channel of the ROI of the coated eyeglass. Then, we adoptsymmetrized cross-projection energy analysis for locating defective areas inside the ROI of the coated eyeglass. Finally, we compare the defect detection resultsfor the coated eyeglass with the standard manufacturingquality. An experiment is conducted using real data collected froma Taiwanese eyeglass factory to validate the performance of the proposed framework. This framework achieves a 100% defect detection rate,demonstrating that it is valid and useful for inspecting coated eyeglasses in industries. Full article
(This article belongs to the Special Issue Information Technologies and Electronics)
Open AccessArticle
S-Subgradient Projection Methods with S-Subdifferential Functions for Nonconvex Split Feasibility Problems
Symmetry 2019, 11(12), 1517; https://doi.org/10.3390/sym11121517 (registering DOI) - 14 Dec 2019
Viewed by 104
Abstract
In this paper, the original CQ algorithm, the relaxed CQ algorithm, the gradient projection method (GPM) algorithm, and the subgradient projection method (SPM) algorithm for the convex split feasibility problem are reviewed, and [...] Read more.
In this paper, the original C Q algorithm, the relaxed C Q algorithm, the gradient projection method ( G P M ) algorithm, and the subgradient projection method ( S P M ) algorithm for the convex split feasibility problem are reviewed, and a renewed S P M algorithm with S-subdifferential functions to solve nonconvex split feasibility problems in finite dimensional spaces is suggested. The weak convergence theorem is established. Full article
(This article belongs to the Special Issue Advance in Nonlinear Analysis and Optimization)
Open AccessArticle
Study on Adaptive Cruise Control Strategy for Battery Electric Vehicle Considering Weight Adjustment
Symmetry 2019, 11(12), 1516; https://doi.org/10.3390/sym11121516 (registering DOI) - 13 Dec 2019
Viewed by 114
Abstract
This paper studies control strategies for adaptive cruise control (ACC) systems in battery electric vehicles (BEVs). A hierarchical control structure is adopted for the ACC system, and the structure contains an upper controller and a lower controller. This paper focuses on the upper [...] Read more.
This paper studies control strategies for adaptive cruise control (ACC) systems in battery electric vehicles (BEVs). A hierarchical control structure is adopted for the ACC system, and the structure contains an upper controller and a lower controller. This paper focuses on the upper controller. In the upper controller, model predictive control (MPC) is applied for optimizing multiple objectives in the car-following process. In addition, multiple objectives, including safety, tracking, comfort, and energy economy, can be transformed into a symmetric objective function with constraints in MPC. In the objective function, the corresponding weight matrix for the optimization of multiple objectives is implemented in symmetric form to reduce the computational complexity. The weights in the weight matrix are usually set to be constant. However, the motion states of the own vehicle and the front vehicle change with respect to time during a car-following process, resulting in variation of the driving conditions. MPCs with constant weights do not adapt well to changes in driving conditions, which limits the performance of the ACC system. Therefore, a strategy for weight adjustment is proposed in order to improve the tracking performance, in which some weights in MPC can be adjusted according to the relative velocity of two vehicles in real time. The simulation experiments are carried out to demonstrate the effectiveness of the strategy for weight adjustment. Based on achieving the other control objectives, the ACC system with the weight adjustment has better tracking performance than the ACC system with the constant weight. While the tracking is improved, the energy economy is also improved. Full article
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Open AccessArticle
Radiative Processes of Two Accelerated Entangled Atoms Near Boundaries
Symmetry 2019, 11(12), 1515; https://doi.org/10.3390/sym11121515 (registering DOI) - 13 Dec 2019
Viewed by 95
Abstract
By considering the interaction between a two-atom system and the vacuum massless scalar field in the viewpoint of an instantaneously inertial observer, we study the rates of transition of a uniformly accelerated two-atom system in the symmetric/antisymmetric entangled state near a reflecting boundary [...] Read more.
By considering the interaction between a two-atom system and the vacuum massless scalar field in the viewpoint of an instantaneously inertial observer, we study the rates of transition of a uniformly accelerated two-atom system in the symmetric/antisymmetric entangled state near a reflecting boundary and in a cavity, respectively. We find that both the downward transition | ψ ± | g A g B and the upward transition | ψ ± | e A e B occur for the accelerated two-atom system, as in sharp contrast with the case of a static two-atom system, in which the upward transition can never happen. Similar to the rates of transition of atoms immersed in a thermal bath with the FDU temperature, both the downward transition rate and the upward transition rate are characterized by the Plank factor ( e 2 π ω 0 / a 1 ) 1 . This character of the transition rates is very different from the other radiative properties of the accelerated two-atom system, such as the resonance interatomic energy, for which the revisions of the effects of uniform acceleration are never characterized by such a factor. We show with analytical and numerical results that both the downward transition and the upward transition processes can be effectively manipulated by the atomic non-inertial motion and by the presence of boundaries. By comparing the upward transition rate with the downward transition rate, we discover that, when ω 0 a , with ω 0 and a being the energy space and the proper acceleration of the two-atom system, the disentanglement caused by the upward transition is negligible, while, if ω 0 a , the disentanglement caused by the upward transition becomes as important as that caused by the downward transition. Full article
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Open AccessArticle
New Results on Neutrosophic Extended Triplet Groups Equipped with a Partial Order
Symmetry 2019, 11(12), 1514; https://doi.org/10.3390/sym11121514 (registering DOI) - 13 Dec 2019
Viewed by 107
Abstract
Neutrosophic extended triplet group (NETG) is a novel algebra structure and it is different from the classical group. The major concern of this paper is to present the concept of a partially ordered neutrosophic extended triplet group (po-NETG), which is a NETG equipped [...] Read more.
Neutrosophic extended triplet group (NETG) is a novel algebra structure and it is different from the classical group. The major concern of this paper is to present the concept of a partially ordered neutrosophic extended triplet group (po-NETG), which is a NETG equipped with a partial order that relates to its multiplicative operation, and consider properties and structure features of po-NETGs. Firstly, in a po-NETG, we propose the concepts of the positive cone and negative cone, and investigate the structure features of them. Secondly, we study the specificity of the positive cone in a partially ordered weak commutative neutrosophic extended triplet group (po-WCNETG). Finally, we introduce the concept of a po-NETG homomorphism between two po-NETGs, construct a po-NETG on a quotient set by providing a multiplication and a partial order, then we discuss some fundamental properties of them. Full article
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Open AccessArticle
Quantum Estimates of Ostrowski Inequalities for Generalized ϕ-Convex Functions
Symmetry 2019, 11(12), 1513; https://doi.org/10.3390/sym11121513 - 12 Dec 2019
Viewed by 128
Abstract
In this paper, the study is focused on the quantum estimates of Ostrowski type inequalities for q-differentiable functions involving the special function introduced by R.K. Raina which depends on certain parameters. Our methodology involves Jackson’s q-integral, the basic concepts of quantum [...] Read more.
In this paper, the study is focused on the quantum estimates of Ostrowski type inequalities for q-differentiable functions involving the special function introduced by R.K. Raina which depends on certain parameters. Our methodology involves Jackson’s q-integral, the basic concepts of quantum calculus, and a generalization of a class of special functions used in the frame of convex sets and convex functions. As a main result, some quantum estimates for the aforementioned inequality are established and some cases involving the special hypergeometric and Mittag–Leffler functions have been studied and some known results are deduced. Full article
Open AccessArticle
Nonparametric Tensor Completion Based on Gradient Descent and Nonconvex Penalty
by Kai Xu and Zhi Xiong
Symmetry 2019, 11(12), 1512; https://doi.org/10.3390/sym11121512 (registering DOI) - 12 Dec 2019
Viewed by 143
Abstract
Existing tensor completion methods all require some hyperparameters. However, these hyperparameters determine the performance of each method, and it is difficult to tune them. In this paper, we propose a novel nonparametric tensor completion method, which formulates tensor completion as an unconstrained optimization [...] Read more.
Existing tensor completion methods all require some hyperparameters. However, these hyperparameters determine the performance of each method, and it is difficult to tune them. In this paper, we propose a novel nonparametric tensor completion method, which formulates tensor completion as an unconstrained optimization problem and designs an efficient iterative method to solve it. In each iteration, we not only calculate the missing entries by the aid of data correlation, but consider the low-rank of tensor and the convergence speed of iteration. Our iteration is based on the gradient descent method, and approximates the gradient descent direction with tensor matricization and singular value decomposition. Considering the symmetry of every dimension of a tensor, the optimal unfolding direction in each iteration may be different. So we select the optimal unfolding direction by scaled latent nuclear norm in each iteration. Moreover, we design formula for the iteration step-size based on the nonconvex penalty. During the iterative process, we store the tensor in sparsity and adopt the power method to compute the maximum singular value quickly. The experiments of image inpainting and link prediction show that our method is competitive with six state-of-the-art methods. Full article
(This article belongs to the Special Issue Iterative Numerical Functional Analysis with Applications)
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Open AccessArticle
Research on Nonlinear Coupling Anti-Swing Control Method of Double Pendulum Gantry Crane Based on Improved Energy
Symmetry 2019, 11(12), 1511; https://doi.org/10.3390/sym11121511 - 12 Dec 2019
Viewed by 121
Abstract
The double pendulum type gantry crane is a typical symmetry underactuated motion system. It has control problems in that the swing of the payload is difficult to suppress and the precise positioning of the trolley is not accurate. A new nonlinear coupling control [...] Read more.
The double pendulum type gantry crane is a typical symmetry underactuated motion system. It has control problems in that the swing of the payload is difficult to suppress and the precise positioning of the trolley is not accurate. A new nonlinear coupling control method based on improved energy is proposed in this paper. We define coupled control signal among trolley, hook and payload. An improved energy storage function is established based on the new coupling control signal. Consequently, a nonlinear anti-swing controller is constructed straightforwardly, and the closed-loop system stability is subject to strict mathematics analysis by Lyapunov and LaSalle’ s theorem. Moreover, the new energy function based on the coupling behaving between the trolley motion and the payload swing leads to the improved control performance. Numerical simulation results show that the proposed method has better performance than traditional controllers. It not only effectively suppresses the swing of the load and the hook, but also precisely controls the displacement of the trolley. It has strong robustness to the displacement of the payload, the change of the gantry crane parameters and the external disturbance. Full article
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Open AccessFeature PaperReview
Recent Advances in Organocatalyzed Asymmetric Synthesis of Benzopyran and Benzodihydropyran (Chromane) Nuclei
Symmetry 2019, 11(12), 1510; https://doi.org/10.3390/sym11121510 - 12 Dec 2019
Viewed by 106
Abstract
Benzopyran and benzodihydropyran (chromane) nuclei are the core structure of many natural products, in particular flavonoids. Many compounds possessing this structure are nutraceuticals, pharmaceutical nutrients. Therefore, benzopyran and chromane scaffolds are important building blocks in organic synthesis and many efforts have been made [...] Read more.
Benzopyran and benzodihydropyran (chromane) nuclei are the core structure of many natural products, in particular flavonoids. Many compounds possessing this structure are nutraceuticals, pharmaceutical nutrients. Therefore, benzopyran and chromane scaffolds are important building blocks in organic synthesis and many efforts have been made to set up efficient methods for their synthesis. In particular, asymmetric methods are of great importance, being natural products, and generally chiral substances. This review aims to cover literature in the range 2017–first half of 2019. Full article
(This article belongs to the Special Issue Asymmetric Reaction)
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Open AccessArticle
Multivariate Skew-Power-Normal Distributions: Properties and Associated Inference
Symmetry 2019, 11(12), 1509; https://doi.org/10.3390/sym11121509 - 12 Dec 2019
Viewed by 154
Abstract
The univariate power-normal distribution is quite useful for modeling many types of real data. On the other hand, multivariate extensions of this univariate distribution are not common in the statistic literature, mainly skewed multivariate extensions that can be bimodal, for example. In this [...] Read more.
The univariate power-normal distribution is quite useful for modeling many types of real data. On the other hand, multivariate extensions of this univariate distribution are not common in the statistic literature, mainly skewed multivariate extensions that can be bimodal, for example. In this paper, based on the univariate power-normal distribution, we extend the univariate power-normal distribution to the multivariate setup. Structural properties of the new multivariate distributions are established. We consider the maximum likelihood method to estimate the unknown parameters, and the observed and expected Fisher information matrices are also derived. Monte Carlo simulation results indicate that the maximum likelihood approach is quite effective to estimate the model parameters. An empirical application of the proposed multivariate distribution to real data is provided for illustrative purposes. Full article
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Open AccessArticle
Properties of Partially Degenerate Complex Appell Polynomials
Symmetry 2019, 11(12), 1508; https://doi.org/10.3390/sym11121508 - 11 Dec 2019
Viewed by 150
Abstract
Degenerate versions of polynomial sequences have been recently studied to obtain useful properties such as symmetric identities by introducing degenerate exponential-type generating functions. As part of our continued work in degenerate versions of generating functions, we subsequently present our study on degenerate complex [...] Read more.
Degenerate versions of polynomial sequences have been recently studied to obtain useful properties such as symmetric identities by introducing degenerate exponential-type generating functions. As part of our continued work in degenerate versions of generating functions, we subsequently present our study on degenerate complex Appell polynomials by considering a partially degenerate version of the generating functions of ordinary complex Appell polynomials in this paper. We only consider partially degenerate generating functions to retain the crucial properties of the Appell sequence, and we present useful identities and general properties by splitting complex values into their real and imaginary parts; moreover, we provide several explicit examples. Additionally, the differential equations satisfied by degenerate complex Bernoulli and Euler polynomials are derived by the quasi-monomiality principle using Appell-type polynomials. Full article
Open AccessFeature PaperArticle
Supersymmetric NJL-Type Model for a Real Superfield Composite
Symmetry 2019, 11(12), 1507; https://doi.org/10.3390/sym11121507 - 11 Dec 2019
Viewed by 165
Abstract
The Nambu–Jona-Lasinio (NJL) model is a classic theory for the strong dynamics of composite fields and symmetry breaking. Supersymmetric versions of the NJL-type models are certainly of interest too. Particularly, the case with a composite (Higgs) chiral superfield formed by two (quark) chiral [...] Read more.
The Nambu–Jona-Lasinio (NJL) model is a classic theory for the strong dynamics of composite fields and symmetry breaking. Supersymmetric versions of the NJL-type models are certainly of interest too. Particularly, the case with a composite (Higgs) chiral superfield formed by two (quark) chiral superfields has received much attention. Here, we propose a prototype model with a four-chiral-superfield interaction, giving a real superfield composite. It has a spin-one composite vector field with properties being somewhat similar to a massive gauge boson of spontaneously broken gauge symmetry. As such, it is like the first supersymmetric analog to non-supersymmetric models with spin-one composites. The key formulation developed here is the picture of quantum effective action as a superfield functional with parameters like constant superfields, having explicit supersymmetric and Grassmann number dependent supersymmetry breaking parts. Following the standard non-perturbative analysis for NJL-type models, the gap equation analysis shows plausible signature of dynamical supersymmetry breaking which is worth more serious analysis. With an extra superfield model Lagrangian included, comparison between the models and their non-supersymmetric counterparts is discussed, illustrating the notion of supersymmetrization is nontrivial in the setting. Full article
(This article belongs to the Special Issue Modern Application of Symmetry Principles to High Energy Physics)
Open AccessArticle
Model of Threats to Computer Network Software
Symmetry 2019, 11(12), 1506; https://doi.org/10.3390/sym11121506 - 11 Dec 2019
Viewed by 143
Abstract
This article highlights the issue of identifying information security threats to computer networks. The aim of the study is to increase the number of identified threats. Firstly, it was carried out the analysis of computer network models used to identify threats, as well [...] Read more.
This article highlights the issue of identifying information security threats to computer networks. The aim of the study is to increase the number of identified threats. Firstly, it was carried out the analysis of computer network models used to identify threats, as well as in approaches to building computer network threat models. The shortcomings that need to be corrected are highlighted. On the basis of the mathematical apparatus of attributive metagraphs, a computer network model is developed that allows to describe the software components of computer networks and all possible connections between them. On the basis of elementary operations on metagraphs, a model of threats to the security of computer network software is developed, which allows compiling lists of threats to the integrity and confidentiality of computer network software. These lists include more threats in comparison with the considered analogues. Full article
(This article belongs to the Special Issue Information Technologies and Electronics)
Open AccessArticle
Digital Watermarking Image Compression Method Based on Symmetric Encryption Algorithms
Symmetry 2019, 11(12), 1505; https://doi.org/10.3390/sym11121505 - 11 Dec 2019
Viewed by 120
Abstract
A digital watermarking image compression method based on symmetrical encryption algorithm is proposed in this study. First, the original image and scrambled watermarking image are processed by wavelet transform, and then the watermarking image processed by the Arnold replacement method is transformed into [...] Read more.
A digital watermarking image compression method based on symmetrical encryption algorithm is proposed in this study. First, the original image and scrambled watermarking image are processed by wavelet transform, and then the watermarking image processed by the Arnold replacement method is transformed into a meaningless image in the time domain to achieve the effect of encryption. Watermarking is generated by embedding the watermarking image into the important coefficients of the wavelet transform. As an inverse process of watermarking embedding, watermarking extraction needs to be reconstructed by the wavelet transform. Finally, the watermarking is extracted from the inverse scrambled watermarking image, and a new symmetrically encrypted digital watermarking image is obtained. The compression method compresses the embedded digital watermarking image, so that the volume of the compressed watermarking image is greatly reduced when the visual difference is very small. The experimental results show that the watermarking image encrypted by this method not only has good transparency, but also has strong anti-brightness/contrast attack, anti-shearing, and anti-noise performance. When the volume of the compressed image is greatly reduced, the root mean square error and visual difference measurement of the watermarking image are very small. Full article
Open AccessArticle
Variance Ranking for Multi-Classed Imbalanced Datasets: A Case Study of One-Versus-All
Symmetry 2019, 11(12), 1504; https://doi.org/10.3390/sym11121504 - 11 Dec 2019
Viewed by 122
Abstract
Imbalanced classes in multi-classed datasets is one of the most salient hindrances to the accuracy and dependable results of predictive modeling. In predictions, there are always majority and minority classes, and in most cases it is difficult to capture the members of item [...] Read more.
Imbalanced classes in multi-classed datasets is one of the most salient hindrances to the accuracy and dependable results of predictive modeling. In predictions, there are always majority and minority classes, and in most cases it is difficult to capture the members of item belonging to the minority classes. This anomaly is traceable to the designs of the predictive algorithms because most algorithms do not factor in the unequal numbers of classes into their designs and implementations. The accuracy of most modeling processes is subjective to the ever-present consequences of the imbalanced classes. This paper employs the variance ranking technique to deal with the real-world class imbalance problem. We augmented this technique using one-versus-all re-coding of the multi-classed datasets. The proof-of-concept experimentation shows that our technique performs better when compared with the previous work done on capturing small class members in multi-classed datasets. Full article
Open AccessArticle
A Cross-Efficiency Evaluation Method Based on Evaluation Criteria Balanced on Interval Weights
Symmetry 2019, 11(12), 1503; https://doi.org/10.3390/sym11121503 - 11 Dec 2019
Viewed by 117
Abstract
Cross-efficiency evaluation approaches and common set of weights (CSW) approaches have long been suggested as two of the more important and effective methods for the ranking of decision making units (DMUs) in data envelopment analysis (DEA). The former emphasizes the flexibility of evaluation [...] Read more.
Cross-efficiency evaluation approaches and common set of weights (CSW) approaches have long been suggested as two of the more important and effective methods for the ranking of decision making units (DMUs) in data envelopment analysis (DEA). The former emphasizes the flexibility of evaluation and its weights are asymmetric, while the latter focuses on the standardization of evaluation and its weights are symmetrical. As a compromise between these two approaches, this paper proposes a cross-efficiency evaluation method that is based on two types of flexible evaluation criteria balanced on interval weights. The evaluation criteria can be regarded as macro policy—or means of regulation—according to the industry’s current situation. Unlike current cross-efficiency evaluation methods, which tend to choose the set of weights for peer evaluation based on certain preferences, the cross-efficiency evaluation method based on evaluation criterion determines one set of input and output weights for each DMU. This is done by minimizing the difference between the weights of the DMU and the evaluation criteria, thus ensuring that the cross-evaluation of all DMUs for evaluating peers is as consistent as possible. This method also eliminates prejudice and arbitrariness from peer evaluations. As a result, the proposed cross-efficiency evaluation method not only looks for non-zero weights, but also ranks efficient DMUs completely. The proposed DEA model can be further extended to seek a common set of weights for all DMUs. Numerical examples are provided to illustrate the applications of the cross-efficiency evaluation method based on evaluation criterion in DEA ranking. Full article
Open AccessArticle
Hybrid Algorithms for Variational Inequalities Involving a Strict Pseudocontraction
Symmetry 2019, 11(12), 1502; https://doi.org/10.3390/sym11121502 - 11 Dec 2019
Viewed by 120
Abstract
In a real Hilbert space, we investigate the Tseng’s extragradient algorithms with hybrid adaptive step-sizes for treating a Lipschitzian pseudomonotone variational inequality problem and a strict pseudocontraction fixed-point problem, which are symmetry. By imposing some appropriate weak assumptions on parameters, we obtain a [...] Read more.
In a real Hilbert space, we investigate the Tseng’s extragradient algorithms with hybrid adaptive step-sizes for treating a Lipschitzian pseudomonotone variational inequality problem and a strict pseudocontraction fixed-point problem, which are symmetry. By imposing some appropriate weak assumptions on parameters, we obtain a norm solution of the problems, which solves a certain hierarchical variational inequality. Full article
(This article belongs to the Special Issue Symmetry in Nonlinear Functional Analysis and Optimization Theory)
Open AccessArticle
Oscillation Criteria for Third Order Neutral Generalized Difference Equations with Distributed Delay
Symmetry 2019, 11(12), 1501; https://doi.org/10.3390/sym11121501 - 11 Dec 2019
Viewed by 129
Abstract
This paper aims to investigate the criteria of behavior of a certain type of third order neutral generalized difference equations with distributed delay. With the technique of generalized Riccati transformation and Philos-type method, we obtain criteria to ensure convergence and oscillatory solutions and [...] Read more.
This paper aims to investigate the criteria of behavior of a certain type of third order neutral generalized difference equations with distributed delay. With the technique of generalized Riccati transformation and Philos-type method, we obtain criteria to ensure convergence and oscillatory solutions and suitable examples are provided to illustrate the main results. Full article
(This article belongs to the Special Issue Differential and Difference Equations and Symmetry)
Open AccessArticle
Some Integral Inequalities for h-Godunova-Levin Preinvexity
Symmetry 2019, 11(12), 1500; https://doi.org/10.3390/sym11121500 - 11 Dec 2019
Viewed by 129
Abstract
In this study, we define new classes of convexity called h-Godunova–Levin and h-Godunova–Levin preinvexity, through which some new inequalities of Hermite–Hadamard type are established. These new classes are the generalization of several known convexities including the s-convex, P-function, and [...] Read more.
In this study, we define new classes of convexity called h-Godunova–Levin and h-Godunova–Levin preinvexity, through which some new inequalities of Hermite–Hadamard type are established. These new classes are the generalization of several known convexities including the s-convex, P-function, and Godunova–Levin. Further, the properties of the h-Godunova–Levin function are also discussed. Meanwhile, the applications of h-Godunova–Levin Preinvex function are given. Full article
Open AccessArticle
An Analysis of the Dynamical Behaviour of Systems with Fractional Damping for Mechanical Engineering Applications
Symmetry 2019, 11(12), 1499; https://doi.org/10.3390/sym11121499 - 11 Dec 2019
Viewed by 136
Abstract
Fractional derivative models are widely used to easily characterise more complex damping behaviour than the viscous one, although the underlying properties are not trivial. Several studies about the mathematical properties can be found, but are usually far from the most daily applications. Thus, [...] Read more.
Fractional derivative models are widely used to easily characterise more complex damping behaviour than the viscous one, although the underlying properties are not trivial. Several studies about the mathematical properties can be found, but are usually far from the most daily applications. Thus, this paper studies the properties of structural systems whose damping is represented by a fractional model from the point of view of a mechanical engineer. First, a single-degree-of-freedom system with fractional damping is analysed. Specifically, the distribution of the poles and the dynamic response to several excitations is studied for different model parameter values highlighting dissimilarities from systems with conventional viscous damping. In fact, thanks to fractional models, particular behaviours are observed that cannot be reproduced by classical ones. Finally, the dynamics of a machine shaft supported by two bearings presenting fractional damping is analysed. The study is carried out by the Finite Element method, deriving in a system with symmetric matrices. Eigenvalues and eigenvectors are obtained by means of an iterative method, and the effect of damping is visualised on the mode shapes. In addition, the response to a perturbation is computed, revealing the influence of the model parameters on the resulting vibration. Full article
(This article belongs to the Special Issue Symmetry in Mechanical Engineering)
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Open AccessArticle
Multi-Attribute Decision-Making Based on m-Polar Fuzzy Hamacher Aggregation Operators
Symmetry 2019, 11(12), 1498; https://doi.org/10.3390/sym11121498 - 10 Dec 2019
Viewed by 191
Abstract
In this paper, we introduce certain aggregation operators, namely, the m-polar fuzzy (mF) Hamacher weighted average operator, mF Hamacher ordered weighted average (mFHOWA) operator, mF Hamacher hybrid average (mFHHA) operator, mF Hamacher weighted [...] Read more.
In this paper, we introduce certain aggregation operators, namely, the m-polar fuzzy (mF) Hamacher weighted average operator, mF Hamacher ordered weighted average (mFHOWA) operator, mF Hamacher hybrid average (mFHHA) operator, mF Hamacher weighted geometric (mFHWG) operator, mF Hamacher weighted ordered geometric operator, and mF Hamacher hybrid geometric (mFHHG) operator. We discuss some properties of these operators, inclusive of their ability to implement both symmetric and asymmetric treatments of the items. We develop an algorithmic model to solve multi-attribute decision-making (MADM) problems in mF environment using mF Hamacher weighted average operator (mFHWA) and mFHWG operators. They can compensate for the possible asymmetric roles of the attributes that describe the problem. In the end, to prove the validity and feasibility of the proposed work, we give applications for selecting the most affected country regarding human trafficking, selecting health care waste treatment methods and selecting the best company for investment. We also solve practical MADM problems by using ELECTRE-I method, and give a comparative analysis. Full article
Open AccessArticle
On the Fekete–Szegö Type Functionals for Close-to-Convex Functions
Symmetry 2019, 11(12), 1497; https://doi.org/10.3390/sym11121497 - 10 Dec 2019
Viewed by 133
Abstract
In this paper, we consider two functionals of the Fekete–Szegö type Θf(μ)=a4-μa2a3 and Φf(μ)=a2a4-μa32 for a [...] Read more.
In this paper, we consider two functionals of the Fekete–Szegö type Θ f ( μ ) = a 4 - μ a 2 a 3 and Φ f ( μ ) = a 2 a 4 - μ a 3 2 for a real number μ and for an analytic function f ( z ) = z + a 2 z 2 + a 3 z 3 + , | z | < 1 . This type of research was initiated by Hayami and Owa in 2010. They obtained results for functions satisfying one of the conditions ( o r (){f’(z) }> , α [ 0 , 1 ) . S i m i l a r e s t i m a t e s w e r e a l s o d e r i v e d f o r u n i v a l e n t s t a r l i k e f u n c t i o n s a n d f o r u n i v a l e n t c o n v e x f u n c t i o n s . W e d i s c u s s &#x00398;f() a n d &#x003A6;f() f o r c l o s e - t o - c o n v e x f u n c t i o n s s u c h t h a t f ( z ) = h ( z ) / ( 1 - z ) 2 , w h e r e h i s a n a n a l y t i c f u n c t i o n w i t h a p o s i t i v e r e a l p a r t . M a n y c o e f f i c i e n t p r o b l e m s , a m o n g o t h e r s e s t i m a t i n g o f &#x00398;f(),&#x003A6;f() o r t h e H a n k e l d e t e r m i n a n t s f o r c l o s e - t o - c o n v e x f u n c t i o n s o r u n i v a l e n t f u n c t i o n s , a r e n o t s o l v e d y e t . O u r r e s u l t s b r o a d e n t h e s c o p e o f t h e o r e t i c a l r e s u l t s c o n n e c t e d w i t h t h e s e f u n c t i o n a l s d e f i n e d f o r d i f f e r e n t s u b c l a s s e s o f a n a l y t i c u n i v a l e n t f u n c t i o n s . Full article
Open AccessArticle
Some New Identities of Second Order Linear Recurrence Sequences
Symmetry 2019, 11(12), 1496; https://doi.org/10.3390/sym11121496 - 10 Dec 2019
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Abstract
The main purpose of this paper is using the combinatorial method, the properties of the power series and characteristic roots to study the computational problem of the symmetric sums of a certain second-order linear recurrence sequences, and obtain some new and interesting identities. [...] Read more.
The main purpose of this paper is using the combinatorial method, the properties of the power series and characteristic roots to study the computational problem of the symmetric sums of a certain second-order linear recurrence sequences, and obtain some new and interesting identities. These results not only improve on some of the existing results, but are also simpler and more beautiful. Of course, these identities profoundly reveal the regularity of the second-order linear recursive sequence, which can greatly facilitate the calculation of the symmetric sums of the sequences in practice. Full article
Open AccessArticle
The Influence of AlGaN/GaN Heteroepitaxial Structure Fractal Geometry on Size Effects in Microwave Characteristics of AlGaN/GaN HEMTs
Symmetry 2019, 11(12), 1495; https://doi.org/10.3390/sym11121495 - 09 Dec 2019
Viewed by 145
Abstract
The investigation of size effects appearing in the dependence of AlGaN/GaN HEMT high-frequency characteristics on channel width d and number of sections n is conducted using the notions of measure, metric and normed functional (linear) spaces. In accordance with the results obtained, in [...] Read more.
The investigation of size effects appearing in the dependence of AlGaN/GaN HEMT high-frequency characteristics on channel width d and number of sections n is conducted using the notions of measure, metric and normed functional (linear) spaces. In accordance with the results obtained, in local approximation the phenomenon of similarity can exist, not only in metric spaces of heteroepitaxial structures, but also in the defined on them functional spaces of the measures of these structures’ additive electrophysical characteristics. This provides means to associate size effects of the HEMTs with their structure material fractal geometry. The approach proposed in the work gives an opportunity, not only to predict the size of the structural elements (e.g., channel width and number of sections) of the transistor with the desired characteristics, but also to reconstruct its compact model parameters, which significantly speeds up the development and optimization of the HEMTs with the desired device characteristics. At transferring to the global approximation, when the topological and fractal dimensions of the structure coincide, its electrophysical characteristics, and subsequently, the values of the compact model equivalent circuit parameters, as well as HEMT high frequency characteristics, follow the classic (linear) laws peculiar to the spaces of integer topological dimensions DT. Full article
(This article belongs to the Special Issue Information Technologies and Electronics)
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Open AccessFeature PaperArticle
Human Visual Perception-Based Multi-Exposure Fusion Image Quality Assessment
Symmetry 2019, 11(12), 1494; https://doi.org/10.3390/sym11121494 - 09 Dec 2019
Viewed by 169
Abstract
Compared with ordinary single exposure images, multi-exposure fusion (MEF) images are prone to color imbalance, detail information loss and abnormal exposure in the process of combining multiple images with different exposure levels. In this paper, we proposed a human visual perception-based multi-exposure fusion [...] Read more.
Compared with ordinary single exposure images, multi-exposure fusion (MEF) images are prone to color imbalance, detail information loss and abnormal exposure in the process of combining multiple images with different exposure levels. In this paper, we proposed a human visual perception-based multi-exposure fusion image quality assessment method by considering the related perceptual features (i.e., color, dense scale invariant feature transform (DSIFT) and exposure) to measure the quality degradation accurately, which is closely related to the symmetry principle in human eyes. Firstly, the L1 norm of chrominance components between fused images and the designed pseudo images with the most severe color attenuation is calculated to measure the global color degradation, and the color saturation similarity is added to eliminate the influence of color over-saturation. Secondly, a set of distorted images under different exposure levels with strong edge information of fused image is constructed through the structural transfer, thus DSIFT similarity and DSIFT saturation are computed to measure the local detail loss and enhancement, respectively. Thirdly, Gauss exposure function is used to detect the over-exposure or under-exposure areas, and the above perceptual features are aggregated with random forest to predict the final quality of fused image. Experimental results on a public MEF subjective assessment database show the superiority of the proposed method with the state-of-the-art image quality assessment models. Full article
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Open AccessArticle
Handcrafted versus CNN Features for Ear Recognition
Symmetry 2019, 11(12), 1493; https://doi.org/10.3390/sym11121493 - 08 Dec 2019
Viewed by 254
Abstract
Ear recognition is an active research area in the biometrics community with the ultimate goal to recognize individuals effectively from ear images. Traditional ear recognition methods based on handcrafted features and conventional machine learning classifiers were the prominent techniques during the last two [...] Read more.
Ear recognition is an active research area in the biometrics community with the ultimate goal to recognize individuals effectively from ear images. Traditional ear recognition methods based on handcrafted features and conventional machine learning classifiers were the prominent techniques during the last two decades. Arguably, feature extraction is the crucial phase for the success of these methods due to the difficulty in designing robust features to cope with the variations in the given images. Currently, ear recognition research is shifting towards features extracted by Convolutional Neural Networks (CNNs), which have the ability to learn more specific features robust to the wide image variations and achieving state-of-the-art recognition performance. This paper presents and compares ear recognition models built with handcrafted and CNN features. First, we experiment with seven top performing handcrafted descriptors to extract the discriminating ear image features and then train Support Vector Machines (SVMs) on the extracted features to learn a suitable model. Second, we introduce four CNN based models using a variant of the AlexNet architecture. The experimental results on three ear datasets show the superior performance of the CNN based models by 22%. To further substantiate the comparison, we perform visualization of the handcrafted and CNN features using the t-distributed Stochastic Neighboring Embedding (t-SNE) visualization technique and the characteristics of features are discussed. Moreover, we conduct experiments to investigate the symmetry of the left and right ears and the obtained results on two datasets indicate the existence of a high degree of symmetry between the ears, while a fair degree of asymmetry also exists. Full article
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Open AccessArticle
Efficient Vanishing Point Detection for Driving Assistance Based on Visual Saliency Map and Image Segmentation from a Vehicle Black-Box Camera
Symmetry 2019, 11(12), 1492; https://doi.org/10.3390/sym11121492 - 07 Dec 2019
Viewed by 217
Abstract
Techniques for detecting a vanishing point (VP) which estimates the direction of a vehicle by analyzing its relationship with surrounding objects have gained considerable attention recently. VPs can be used to support safe vehicle driving in areas such as for autonomous driving, lane-departure [...] Read more.
Techniques for detecting a vanishing point (VP) which estimates the direction of a vehicle by analyzing its relationship with surrounding objects have gained considerable attention recently. VPs can be used to support safe vehicle driving in areas such as for autonomous driving, lane-departure avoidance, distance estimation, and road-area detection, by detecting points in which parallel extension lines of objects are concentrated at a single point in a 3D space. In this paper, we proposed a method of detecting the VP in real time for applications to intelligent safe-driving support systems. In order to support safe driving of autonomous vehicles, it is necessary to drive the vehicle with the VP in center of the road image in order to prevent the vehicle from moving out of the road area while driving. Accordingly, in order to detect the VP in the road image, a method of detecting a point where straight lines intersect in an area where edge directional feature information is concentrated is required. The visual attention model and image segmentation process are applied to quickly identify candidate VPs in the area where the edge directional feature-information is concentrated and the intensity contrast difference is large. In the proposed method, VPs are detected by analyzing the edges, visual-attention regions, linear components using the Hough transform, and image segmentation results in an input image. Our experimental results have shown that the proposed method could be applied to safe-driving support systems. Full article
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Open AccessArticle
Complete Geometric Analysis Using the Study SE(3) Parameters for a Novel, Minimally Invasive Robot Used in Liver Cancer Treatment
Symmetry 2019, 11(12), 1491; https://doi.org/10.3390/sym11121491 - 07 Dec 2019
Viewed by 229
Abstract
The paper presents a complete geometric analysis of a novel parallel medical robotic system designed for minimally invasive treatment of hepatic tumors using brachytherapy, ablation or targeted chemotherapy. An algebraic method based on the study parameters of the special Euclidean transformation Lie group [...] Read more.
The paper presents a complete geometric analysis of a novel parallel medical robotic system designed for minimally invasive treatment of hepatic tumors using brachytherapy, ablation or targeted chemotherapy. An algebraic method based on the study parameters of the special Euclidean transformation Lie group SE(3) was used to determine the mechanism kinematics singularities and workspace. Moreover, two particular medical tool manipulations for the minimally invasive medical procedures are defined in terms of the Study parameters. The first manipulation of the medical tool refers to the linear insertion (of e.g., needles) and the second one is the remote center of motion manipulation of specific medical instruments (e.g., ultrasound probes). The constraint equations of the robotic system are derived and then, the operational workspace is illustrated for the novel parallel robotic system. Lastly, a numerical simulation is presented showing the behavior of the robotic system manipulating the ultrasound probe constrained by the remote center of motion. The geometric analysis of the operational workspace and the numerical simulation show promising results that validate the novel robotic system (safe-wise) for the medical procedure. Full article
(This article belongs to the Special Issue Symmetry in Mechanical Engineering)
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