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On (?)-Lorentzian para-Sasakian Manifolds
The object of this paper is to study (?)-Lorentzian para-Sasakian manifolds. Some typical identities for the curvature tensor and the Ricci tensor of (?)-Lorentzian para-Sasakian manifold are investi-gated. Further, we study globally ?-Ricci symmetric and weakly ?-Ricci symmetric (?)-Lorentzian para-Sasakian manifolds and obtain interesting results. 2022 Academic Center for Education, Culture and Research TMU. -
On (k) -coloring of generalized Petersen graphs
The chromatic number, ?(G) of a graph G is the minimum number of colors used in a proper coloring of G. In an improper coloring, an edge uv is bad if the colors assigned to the end vertices of the edge is the same. Now, if the available colors are less than that of the chromatic number of graph G, then coloring the graph with the available colors leads to bad edges in G. In this paper, we use the concept of (k)-coloring and determine the number of bad edges in generalized Petersen graph (P(n,t)). The number of bad edges which result from a (k)-coloring of G is denoted by bk(G). 2022 World Scientific Publishing Company. -
On /delta^(k)-colouring of Powers of Paths and Cycles
In animpropervertexcolouringofagraph,adjacentverticesarepermittedto receivesamecolours.Anedgeofanimproperlycolouredgraphissaidtobeabad edge ifitsendverticeshavethesamecolour.Anear-propercolouringofagraphis a colouringwhichminimisesthenumberofbadedgesbyrestrictingthenumberof colour classes that can have adjacency among their own elements. The ?(k)- colouring is anear-propercolouringof G consisting of k givencolours,where1 ? k ? ?(G) ? 1, whichminimisesthenumberofbadedgesbypermittingatmostonecolourclassto have adjacency among the vertices in it. In this paper,we discuss the number of bad edges ofpowers of paths and cycles. Published by Digital Commons@Georgia Southern, 2021. 2021 Georgia Southern University. All rights reserved. -
ON 3-DIMENSIONAL QUASI-PARA-SASAKIAN MANIFOLDS AND RICCI SOLITONS
The purpose of this paper is to study 3-dimensional quasi-para-Sasakian manifolds and Ricci solitons. First, we prove that a 3-dimensional non-paracosymplectic quasi-para-Sasakian manifold is an ?-Einstein manifold if and only if the structure function ? is constant. Further, it is shown that a Ricci soliton on a 3-dimensional quasi-para-Sasakian manifold with ?=constant is expanding. Moreover, we show that if a 3-dimensional quasi-para-Sasakian manifold admits a Ricci soliton, then the flow vector field V is Killing, and the quasi-para-Sasakian structure can be obtained by a homothetic deformation of a para-Sasakian structure. Besides, we study gradient Ricci solitons and prove that if a 3-dimensional non-paracosymplectic quasi-para-Sasakian manifold with ?=constant admits a gradient Ricci soliton, then the manifold is an Einstein one. Also, a suitable example of a 3-dimensional quasi-para-Sasakian manifold is constructed to verify our results. 2022 A. Razmadze Mathematical Institute of Iv. Javakhishvili Tbilisi State University. All rights reserved. -
On a Mixture of the Lindley and Modified Lindley Distributions: Properties and Estimation
In this article, we investigate a novel three-parameter lifetime distribution constructed from a mixture of the original Lindley and modified Lindley distributions. The concept behind this construction is to combine the contrasting properties of these two well-known distributions to provide a new statistical modeling option for lifetime data analysis. In particular, it provides a natural alternative to the three-parameter, two-component mixture of the Lindley distribution, which has attracted attention in the recent statistical literature. We investigate its main properties from both a theoretical and practical point of view. The shapes of the corresponding probability density and hazard rate functions and the formulas for the moments, moment generating functions and characteristic functions are discussed. The distribution is then subjected to statistical analysis, considering it as a semi-parametric model. The maximum likelihood approach is used to estimate the parameters. In a simulation analysis, the numerical behavior of the bias and the mean square error of the obtained estimates are studied. The new model is tested on three data sets and the results show that it has a better fit behavior than its main competitor, the three-parameter two-component mixture of the Lindley model. 2025 YU -
On an anti-torqued vector field on riemannian manifolds
A torqued vector field ? is a torse-forming vector field on a Riemannian manifold that is orthogonal to the dual vector field of the 1-form in the definition of torse-forming vector field. In this paper, we introduce an anti-torqued vector field which is opposite to torqued vector field in the sense it is parallel to the dual vector field to the 1-form in the definition of torse-forming vector fields. It is interesting to note that anti-torqued vector fields do not reduce to concircular vector fields nor to Killing vector fields and thus, give a unique class among the classes of special vector fields on Riemannian manifolds. These vector fields do not exist on compact and simply connected Riemannian manifolds. We use anti-torqued vector fields to find two characterizations of Euclidean spaces. Furthermore, a characterization of an Einstein manifold is obtained using the combination of a torqued vector field and FischerMarsden equation. We also find a condition under which the scalar curvature of a compact Riemannian manifold admitting an anti-torqued vector field is strictly negative. 2021 by the authors. Licensee MDPI, Basel, Switzerland. -
On an extension of the two-parameter Lindley distribution
AIM: Lindley distribution has been widely studied in statistical literature because it accommodates several interesting properties. In lifetime data analysis contexts, Lindley distribution gives a good description over exponential distribution. It has been used for analysing copious real data sets, specifically in applications of modeling stress-strength reliability. This paper proposes a new generalized two-parameter Lindley distribution and provides a comprehensive description of its statistical properties such as order statistics, limiting distributions of order statistics, Information theory measures, etc. METHODS: We study shapes of the probability density and hazard rate functions, quantiles, moments, moment generating function, order statistic, limiting distributions of order statistics, information theory measures, and autoregressive models are among the key characteristics and properties discussed. The two-parameter Lindley distribution is then subjected to statistical analysis. The paper uses methods of maximum likelihood to estimate the parameters of the proposed distribution. The usefulness of the proposed distribution for modeling data is illustrated using a real data set by comparison with other generalizations of the exponential and Lindley distributions and is depicted graphically. RESULTS/FINDINGS: This paper presents relevant characteristics of the proposed distribution and applications. Based on this study, we found that the proposed model can be used quite effectively to analyzing lifetime data. CONCLUSIONS: In this article, we proffered a new customized Lindley distribution. The proposed distribution enfolds exponential and Lindley distributions as sub-models. Some properties of this distribution such as quantile function, moments, moment generating function, distributions of order statistics, limiting distributions of order statistics, entropy, and autoregressive time series models are studied. This distribution is found to be the most appropriate model to fit the carbon fibers data compared to other models. Consequently, we propose the MOTL distribution for sketching inscrutable lifetime data sets. 2023 DSR Publishers/The University of Jordan. -
On Automatic Target Recognition (ATR) using Inverse Synthetic Aperture Radar Images
Inverse Synthetic Aperture Radar (ISAR) is used to image sea surface targets during day/night and all-weather capabilities for applications such as coastal surveillance, ship self-defense, suppression of drug trafficking etc. Hence automating classification of ships by means of machine learning methods has become more significant. Typical classification approaches consist of pre-processing, feature extraction and processing by classifiers. Image processing techniques are applied for pre-processing ISAR images. Transformation invariant features are then extracted to which classifiers such as SVM, Neural Networks (NNs) are applied. The performance of these algorithms depend on the manually chosen features and is trained to perform well for different target profiles. The target image (profile of target) varies depending on the target type, aspect angle and motion introduced due to different sea states. In addition, Deep learning methods are also being explored for classification of ships. The challenge is to classify ships for different sea conditions and image acquisition parameters with limited database and processing resource. 2023 IEEE. -
On becoming a demanding Community: Neelam and its March for Justice
The Neelam Panpattu Maiyam (Neelam Cultural Centre), an anti-caste socio-cultural movement based in Tamil Nadu, has emerged as a political force following its March for Justice rally in response to the murder of Dalit leader, K. Armstrong of Bahujan Samaj Party (BSP). The rally caused unease not only among mainstream political parties but also within certain Dalit political factions, with the media claiming it created divisions within Dalit politics. However, the movement, with strong Dalit assertions, confronts the Dravidian political power of the state head-on, which chose to remain silent about the murder. In contrast to those Dalit leaders who appease the state apparatus by compromising Dalit rights, Neelam demanded elected Dalit leaders to firmly stand for the Dalit cause. Given this recent political upheaval, this study delves into Neelams evolving political role in becoming a more vocal and influential force in contemporary political discourse against caste-based injustices, highlighting the significant impact of the March for Justice rally within and beyond the Dalit politics in the state. 2025 Informa UK Limited, trading as Taylor & Francis Group. -
On bivariate Teissier model using Copula: dependence properties, and case studies
To precisely represent bivariate continuous variables, this work presents an innovative approach that emphasizes the interdependencies between the variables. The technique is based on the Teissier model and the Farlie-Gumbel-Morgenstern (FGM) copula and seeks to create a complete framework that captures every aspect of associated occurrences. The work addresses data variability by utilizing the oscillatory properties of the FGM copula and the flexibility of the Teissier model. Both theoretical formulation and empirical realization are included in the evolution, which explains the joint cumulative distribution function F(z1,z2), the marginals F(z1) and F(z2), and the probability density function (PDF) f(z1,z2). The novel modeling of bivariate lifetime phenomena that combines the adaptive properties of the Teissier model with the oscillatory characteristics of the FGM copula represents the contribution. The study emphasizes the effectiveness of the strategy in controlling interdependencies while advancing academic knowledge and practical application in bivariate modelling. In parameter estimation, maximum likelihood and Bayesian paradigms are employed through the use of the Markov Chain Monte Carlo (MCMC). Theorized models are examined closely using rigorous model comparison techniques. The relevance of modern model paradigms is demonstrated by empirical findings from the Burr dataset. The Author(s) under exclusive licence to The Society for Reliability Engineering, Quality and Operations Management (SREQOM), India and The Division of Operation and Maintenance, Lulea University of Technology, Sweden 2024. -
ON BLOCK-RELATED DERIVED GRAPHS
This paper introduces and analyses the block-degree of a vertex and the cut-degree of a block. The block-degree of a vertex v is the number of blocks containing v. The cut-degree of a block b is the number of cut vertices of G contained in b. The block-degree sequence of cut vertices of the graph and the cut-degree sequence of the graph are defined. A few characterizations of the block-degree and cut-degree sequence of the graph are established. Given a graph, its block graph (B(G)) is a graph where each vertex represents a block, and two vertices are connected if their blocks intersect. The number of cut vertices of B(G) is determined. Further, an investigation is carried out on the traversability of B(G). A block cutpoint graph (BC(G)) of a graph represents a graph where each vertex corresponds to either a block or a cut vertex, and two vertices are connected if one represents a block and the other represents a cut vertex contained within that block. The properties of BC(G) and its iterations are studied. The graph G for which BC(G) is a perfect m-ary tree is characterized. 2024, Canadian University of Dubai. All rights reserved. -
On building up a closer psychic distance as a fundamental ground of relationship between India and Korea: Focusing on Jeonlanam-Do in Korea
The Uppsala model (Johanson and Wiedersheim-Paul, 1975) identifies cultural differences, market attractiveness, and core competence of nations or firms as the key factors affecting international market selection. Among these three factors, psychic distance caused by cultural differences is regarded as the most important factor. However, the psychic distance between India and Korea is not very close. The main objective of this paper is to examine the ways to boost economic relationships between India and Korea by building up a closer relationship of psychic distance. We suggest Jeonlanam-Do including Gwangju Metropolitan City (JDGC) in Korea as a stepping stone to make both countries' psychic distance closer as JD has several common grounds of intangible assets with India which includes its adherence to democracy, human rights and peace; the diverse food culture; and the religious zeal to Buddhism. We propose these common interests as a way to enhance the awareness of national brand 'India' in Korea which will attribute to a strategically developed economic relationship between Korea and India. 2022 Inderscience Enterprises Ltd.. All rights reserved. -
On C-Perfection of Modular Product of Graphs
A graph G is said to be C-perfect if, for all induced subgraphs H of G, the induced cycle independence number is equal to its corresponding induce cycle covering number, where every vertex in H belongs to at least one cycle in H. This article deals with the study on C-perfection of modular product of graphs. Through this article, we study various structural properties of C-perfect modular product of graphs and also characterize them. The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025. -
On C-Perfection of Tensor Product of Graphs
A graph G is C-perfect if, for each induced subgraph H in G, the induced cycle independence number of H is equal to its induced cycle covering number. Here, the induced cycle independence number of a graph G is the cardinality of the largest vertex subset of G, whose elements do not share a common induced cycle, and induced cycle covering number is the minimum number of induced cycles in G that covers the vertex set of G. C-perfect graphs are characterized as series-parallel graphs that do not contain any induced subdivisions of K2,3, in literature. They are also isomorphic to the class of graphs that has an IC-tree. In this article, we examine the C-perfection of tensor product of graphs, also called direct product or Kronecker product. The structural properties of C-perfect tensor product of graphs are studied. Further, a characterization for C-perfect tensor product of graphs is obtained. The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024. -
On certain chromatic topological indices of some Mycielski graphs
As a coloring analogue of different Zagreb indices, in the recent literature, the notion of chromatic Zagreb indices has been introduced and studied for some basic graph classes in trees. In this paper, we study the chromatic Zagreb indices and chromatic irregularity indices of some special classes of graphs called Mycielski graphs of paths and cycles. 2020 Yarmouk University. All rights reserved. -
On Certain J-Colouring Parameters of Graphs
In this paper, a new type of colouring called J-colouring is introduced. This colouring concept is motivated by the newly introduced invariant called the rainbow neighbourhood number of a graph. The study ponders on maximal colouring opposed to minimum colouring. An upper bound for a connected graph is presented, and a number of explicit results are presented for cycles, complete graphs, wheel graphs and for a complete l-partite graph. 2019, The National Academy of Sciences, India. -
On certain topological indices of signed graphs
The first Zagreb index of a graph G is the sum of squares of the vertex degrees in a graph and the second Zagreb index of G is the sum of products of degrees of adjacent vertices in G. The imbalance of an edge in G is the numerical difference of degrees of its end vertices and the irregularity of G is the sum of imbalances of all its edges. In this paper, we extend the concepts of these topological indices for signed graphs and discuss the corresponding results on signed graphs. 2020 the author(s). -
On Circulant Completion of Graphs
A graph G with vertex set as {v0, v1, v2,.., vn-1} corresponding to the elements of Zn, the group of integers under addition modulo n, is said to be a circulant graph if the edge set of G consists of all edges of the form {vi, vj} where (i-j)(modn)?S?{1,2,,n-1}, that is, closed under inverses. The set S is known as the connection set. In this paper, we present some techniques and characterisations which enable us to obtain a circulant completion graph of a given graph and thereby evaluate the circulant completion number. The obtained results provide the basic eligibilities for a graph to have a particular circulant completion graph. 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. -
On Combinatorial Handoff Strategies for Spectrum Mobility in Ad Hoc Networks: A Comparative Review
Technological advancements have made communication on-the-go seamless. Spectrum mobility is a networking concept that involves access technologies that allow highly mobile nodes to communicate with each other. Ad-hoc networks are formed between mobile nodes where fixed infrastructure is not used. Due to the lack of such fixed access points for connectivity, the nodes involved make use of the best network available to transmit data. Due to heterogeneous networks involvement, the mobile nodes may face trouble finding the most optimal network for transmission. Existing technologies allow the nodes to select available networks, but the selection process is not optimized, leading to frequent switching. This leads to packet loss, low data rates, high delay, etc. Many researchers have proposed optimal strategies for performing handoff in wireless networks. This paper reviews combinatorial strategies that make use of multiple techniques to perform a handoff. 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. -
On degree product induced signed graphs of graphs
A signed graph is a graph with positive or negative signs assigned to edges. An induced signed graph is a signed graph constructed from a given graph according to some pre-defined protocols. An induced signed graph of a graph G is a signed graph in which each edge uv receives a sign (-1)|?(v)-?(u)|, where ?: V(G) ? ?. In this paper, we discuss degree product induced signed graphs and determine the structural properties of these signed graphs such as balancing, clustering, regularity and co-regularity. 2020 Author(s).