Symmetry

Lakshmi Devi, Gavireddy;Niranjan, Hari

doi: 10.3390/sym14081496pmid: N/A

The significance of radiation, Soret and Dufour’s effects on MHD flow in a porous media near a stagnation point past a vertical plate with slip, temperature, and concentration boundary conditions were investigated. Local similarity variables are used in the solution, which reduces the PDEs into analogous boundary value problem for ODEs. Symmetry analysis can be used to detect these variations in local similarity. To numerically explain the problem, a shooting approach and the MATLAB bvp4c solver are utilized. As the magnetic field and porous medium parameters are raised, the skin friction increases, and the temperature increases as the radiation pointer is increased. As the Soret number grows, the concentration profile rises.

Oks, Eugene

doi: 10.3390/sym14081497pmid: N/A

Atomic processes in plasmas and gases encompass broad areas in theoretical and experimental atomic and molecular physics [...]

Mahad, Zahari;Ariffin, Muhammad Rezal Kamel;Ghafar, Amir Hamzah Abd.;Salim, Nur Raidah

doi: 10.3390/sym14081498pmid: N/A

Rogue certificate authorities (RCA) are third-party entities that intentionally produce key pairs that satisfy publicly known security requirements but contain weaknesses only known to the RCA. This work analyses the Murru–Saettone RSA variant scheme that obtains its key pair from a potential RCA methodology. The Murru–Saettone scheme is based on the cubic Pell equation x3+ry3+r2z3−3rxyz=1. The public, e, and private, d key generation process uses the secret parameter ψ=(p2+p+1)(q2+q+1) in place of the standard Euler–phi function ϕ(N)=(p−1)(q−1), where ed≡1(modψ). We prove that, upon obtaining an approximation of ψ, we are able to identify the provided key pair that was maliciously provided even if the private key d size is approximate to ψ. In fact, we are able to factor the modulus N=pq.

Cantú-González, José Roberto;Hueyotl-Zahuantitla, Filiberto;Castorena-Peña, Jesús Abraham;Aguirre-López, Mario A.

doi: 10.3390/sym14081499pmid: N/A

Spiker–blocker encounters are a key moment for determining the result of a volleyball rally. The characterization of such a moment using physical–statistical parameters allows us to reproduce the possible ball’s trajectory and then make calculations to set up the defense in an optimal way. In this work, we present a computational algorithm that shows the possible worst scenarios of ball trajectories for a volleyball defense, in terms of the covered area by the block and the impact time of the backcourt defense to contact the ball before it reaches the floor. The algorithm is based on the kinematic equations of motion, trigonometry, and statistical parameters of the players. We have called it the Attack-Block-Court Defense algorithm (the ABCD algorithm), since it only requires the 3D-coordinates of the attacker and the blocker, and a discretized court in a number of cells. With those data, the algorithm calculates the percentage of the covered area by the blocker and the time at which the ball impacts the court (impact time). More specifically, the structure of the algorithm consists of setting up the spiker’s and blocker’s locations at the time the spiker hits the ball, and then applying the kinematic equations to calculate the worst scenario for the team in defense. The case of a middle-hitter attack with a single block over the net is simulated, and an analysis of the space of input variables for such a case is performed. We found a strong dependence on the average impact time and the covered area on both the attack–block height’s ratio and the attack height. The standard deviation of the impact time was the variable that showed more asymmetry, respecting the input variables. An asymmetric case considering more variables with a wing spiker and three blockers is also shown, in order to illustrate the potential of the model in a more complex scenario. The results have potential applications, as a supporting tool for coaches in the design of customized defense or attack systems, in the positioning of players according to the prior knowledge of the opponent team, and in the development of replay and video-game technologies in multimedia systems.

Khan, Waseem Ahmad;Alatawi, Maryam Salem

doi: 10.3390/sym14081500pmid: N/A

The main aim of this study is to define degenerate Genocchi polynomials and numbers of the second kind by using logarithmic functions, and to investigate some of their analytical properties and some applications. For this purpose, many formulas and relations for these polynomials, including some implicit summation formulas, differentiation rules and correlations with the earlier polynomials by utilizing some series manipulation methods, are derived. Additionally, as an application, the zero values of degenerate Genocchi polynomials and numbers of the second kind are presented in tables and multifarious graphical representations for these zero values are shown.

Lee, Hosang

doi: 10.3390/sym14081501pmid: N/A

Sandstorm images have a color cast that is reddish or yellowish due to the attenuation of the color channel. When light propagates through sand particles, it is scattered. Additionally, if some sand particles have a certain color, the obtained image in this circumstance experiences a color shift because some color channels are attenuated. Therefore, sandstorm images have a symmetrically distributed color cast throughout the image. There have been many studies aiming to enhance sandstorm images. In many studies, to enhance color-casted images, researchers have used the various methods as with gamma correction. However, artificial color shift occurs in an enhanced image because these methods do not reflect the image’s adaptive feature. This paper proposes a sandstorm image enhancement method using singular value recombination based on rank. The singular value of an image reflects the image’s characteristics adaptively, and improved images using the singular values have no artificial color because the balanced image eliminates the degraded color cast. Because the balanced image has hazy or dusty features, the singular value ratio can be used to enhance the image. The enhanced images produced using the proposed method are superior compared to state-of-the-art methods, objectively and subjectively.

Ji, Yuanfa;He, Jianzhong;Sun, Xiyan;Bai, Yang;Wei, Zhaochuan;Ghazali, Kamarul Hawari bin

doi: 10.3390/sym14081502pmid: N/A

With its outstanding performance and tracking speed, discriminative correlation filters (DCF) have gained much attention in visual object tracking, where time-consuming correlation operations can be efficiently computed utilizing the discrete Fourier transform (DFT) with symmetric properties. Nevertheless, the inherent issues of boundary effects and filter degradation, as well as occlusion and background clutter, degrade the tracking performance. In this work, we proposed an augmented memory joint aberrance repressed correlation filter (AMRCF) for visual tracking. Based on the background-aware correlation filter (BACF), we introduced adaptive spatial regularity to mitigate the boundary effect. Several historical views and the current view are exploited to train the model together as a way to reinforce the memory. Furthermore, aberrance repression regularization was introduced to suppress response anomalies due to occlusion and deformation, while adopting the dynamic updating strategy to reduce the impact of anomalies on the appearance model. Finally, extensive experimental results over four well-known tracking benchmarks indicate that the proposed AMRCF tracker achieved comparable tracking performance to most state-of-the-art (SOTA) trackers.

Ricci, Paolo Emilio

doi: 10.3390/sym14081503pmid: N/A

This Special Issue contains 14 articles from the MDPI journal Symmetry on the general subject area of “Special Functions and Polynomials”, written by scholars belonging to different countries of the world. A similar number of submitted articles was not accepted for publication. Several successful Special Issues on the same or closely related topics have already appeared in MDPI’s Symmetry, Mathematics and Axioms journals, in particular those edited by illustrious colleagues such as Hari Mohan Srivastava, Charles F. Dunkl, Junesang Choi, Taekyun Kim, Gradimir Milovanović, and many others, who testify to the importance of this matter for its applications in every field of mathematical, physical, chemical, engineering and statistical sciences. The subjects treated in this Special Issue include, in particular, the following Keywords.

Alansari, Monairah;Ali, Muhammad Usman

doi: 10.3390/sym14081504pmid: N/A

The concept of symmetry is a very vast topic that is involved in the studies of several phenomena. This concept enables us to discuss the phenomenon in some systematic pattern depending upon the type of phenomenon. Each phenomenon has its own type of symmetry. The phenomenon that is used in the discussion of this article is a symmetric distance-measuring function. This article presents the notions of abstract interpolative Reich-Rus-Ćirić-type contractions with a shrink map and examines the existence of ϕ-fixed points for such maps in complete metric space. These notions are defined through special types of simulation functions. The proof technique of the results presented in this article is easy to understand compared with the existing literature on interpolative Reich-Rus-Ćirić-type contractions.

Friedberg, Richard;Manassah, Jamal T.

doi: 10.3390/sym14081505pmid: N/A

We report computer studies showing how the duration of memory for storage and retrieval of a classical bit can be increased to 100 times the decay time of an isolated atom, with no use of high-tech cold-atom preparations recently developed in the light-matter field. We suggest that our low-tech procedure can greatly enlarge the number of experimenters able to enter this field. The role of symmetry in this procedure arises in a careful interplay of incoherent and coherent excitations of a large collection of “two-level” atoms, the level separation being matched by the dominant frequency of the electromagnetic fields (short pulses and continuing field) applied to the system.