557 results on '"M, Rajesh"'
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2. Code Generation for a Variety of Accelerators for a Graph DSL
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Kumar, Ashwina, Krishna, M. Venkata, Bartakke, Prasanna, Kumar, Rahul, M, Rajesh Pandian, Behera, Nibedita, and Nasre, Rupesh
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Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
Sparse graphs are ubiquitous in real and virtual worlds. With the phenomenal growth in semi-structured and unstructured data, sizes of the underlying graphs have witnessed a rapid growth over the years. Analyzing such large structures necessitates parallel processing, which is challenged by the intrinsic irregularity of sparse computation, memory access, and communication. It would be ideal if programmers and domain-experts get to focus only on the sequential computation and a compiler takes care of auto-generating the parallel code. On the other side, there is a variety in the number of target hardware devices, and achieving optimal performance often demands coding in specific languages or frameworks. Our goal in this work is to focus on a graph DSL which allows the domain-experts to write almost-sequential code, and generate parallel code for different accelerators from the same algorithmic specification. In particular, we illustrate code generation from the StarPlat graph DSL for NVIDIA, AMD, and Intel GPUs using CUDA, OpenCL, SYCL, and OpenACC programming languages. Using a suite of ten large graphs and four popular algorithms, we present the efficacy of StarPlat's versatile code generator., Comment: arXiv admin note: text overlap with arXiv:2305.03317
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- 2024
3. Bounds and extremal graphs for the energy of complex unit gain graphs
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Samanta, Aniruddha and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the gain function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $ and its inverse is assigned to the opposite orientation. The associated adjacency matrix $ A(\Phi) $ is defined canonically. The energy $ \mathcal{E}(\Phi) $ of a $ \mathbb{T} $-gain graph $ \Phi $ is the sum of the absolute values of all eigenvalues of $ A(\Phi) $. For any connected triangle-free $ \mathbb{T} $-gain graph $ \Phi $ with the minimum vertex degree $ \delta$, we establish a lower bound $ \mathcal{E}(\Phi)\geq 2\delta$ and characterize the equality. Then, we present a relationship between the characteristic and the matching polynomial of $ \Phi $. Using this, we obtain an upper bound for the energy $ \mathcal{E}(\Phi)\leq 2\mu\sqrt{2\Delta_e+1} $ and characterize the classes of graphs for which the bound sharp, where $ \mu$ and $ \Delta_e$ are the matching number and the maximum edge degree of $ \Phi $, respectively. Further, for any unicyclic graph $ G $, we study the gains for which the gain energy $ \mathcal{E}(\Phi) $ attains the maximum/minimum among all $ \mathbb{T} $-gain graphs defined on $G$.
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- 2023
4. Classification of Dysarthria based on the Levels of Severity. A Systematic Review
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Al-Ali, Afnan, Al-Maadeed, Somaya, Saleh, Moutaz, Naidu, Rani Chinnappa, Alex, Zachariah C, Ramachandran, Prakash, Khoodeeram, Rajeev, and M, Rajesh Kumar
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Computer Science - Machine Learning - Abstract
Dysarthria is a neurological speech disorder that can significantly impact affected individuals' communication abilities and overall quality of life. The accurate and objective classification of dysarthria and the determination of its severity are crucial for effective therapeutic intervention. While traditional assessments by speech-language pathologists (SLPs) are common, they are often subjective, time-consuming, and can vary between practitioners. Emerging machine learning-based models have shown the potential to provide a more objective dysarthria assessment, enhancing diagnostic accuracy and reliability. This systematic review aims to comprehensively analyze current methodologies for classifying dysarthria based on severity levels. Specifically, this review will focus on determining the most effective set and type of features that can be used for automatic patient classification and evaluating the best AI techniques for this purpose. We will systematically review the literature on the automatic classification of dysarthria severity levels. Sources of information will include electronic databases and grey literature. Selection criteria will be established based on relevance to the research questions. Data extraction will include methodologies used, the type of features extracted for classification, and AI techniques employed. The findings of this systematic review will contribute to the current understanding of dysarthria classification, inform future research, and support the development of improved diagnostic tools. The implications of these findings could be significant in advancing patient care and improving therapeutic outcomes for individuals affected by dysarthria., Comment: no comments
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- 2023
5. A note on the distance and distance signless Laplacian spectral radius of complements of trees
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Mahato, Iswar and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
In this article, we show that the generalized tree shift operation increases the distance spectral radius, distance signless Laplacian spectral radius, and the $D_\alpha$-spectral radius of complements of trees. As a consequence of this result, we correct an ambiguity in the proofs of some of the known results.
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- 2023
6. StarPlat: A Versatile DSL for Graph Analytics
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Behera, Nibedita, Kumar, Ashwina, T, Ebenezer Rajadurai, Nitish, Sai, M, Rajesh Pandian, and Nasre, Rupesh
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Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
Graphs model several real-world phenomena. With the growth of unstructured and semi-structured data, parallelization of graph algorithms is inevitable. Unfortunately, due to inherent irregularity of computation, memory access, and communication, graph algorithms are traditionally challenging to parallelize. To tame this challenge, several libraries, frameworks, and domain-specific languages (DSLs) have been proposed to reduce the parallel programming burden of the users, who are often domain experts. However, existing frameworks to model graph algorithms typically target a single architecture. In this paper, we present a graph DSL, named StarPlat, that allows programmers to specify graph algorithms in a high-level format, but generates code for three different backends from the same algorithmic specification. In particular, the DSL compiler generates OpenMP for multi-core, MPI for distributed, and CUDA for many-core GPUs. Since these three are completely different parallel programming paradigms, binding them together under the same language is challenging. We share our experience with the language design. Central to our compiler is an intermediate representation which allows a common representation of the high-level program, from which individual backend code generations begin. We demonstrate the expressiveness of StarPlat by specifying four graph algorithms: betweenness centrality computation, page rank computation, single-source shortest paths, and triangle counting. We illustrate the effectiveness of our approach by comparing the performance of the generated codes with that obtained with hand-crafted library codes. We find that the generated code is competitive to library-based codes in many cases. More importantly, we show the feasibility to generate efficient codes for different target architectures from the same algorithmic specification of graph algorithms., Comment: 30 pages, 21 figures
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- 2023
7. Extremal problems for the eccentricity matrices of complements of trees
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Mahato, Iswar and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
The eccentricity matrix of a connected graph $G$, denoted by $\mathcal{E}(G)$, is obtained from the distance matrix of $G$ by keeping the largest nonzero entries in each row and each column, and leaving zeros in the remaining ones. The $\mathcal{E}$-eigenvalues of $G$ are the eigenvalues of $\mathcal{E}(G)$, in which the largest one is the $\mathcal{E}$-spectral radius of $G$. The $\mathcal{E}$-energy of $G$ is the sum of the absolute values of all $\mathcal{E}$-eigenvalues of $G$. In this article, we study some of the extremal problems for eccentricity matrices of complements of trees and characterize the extremal graphs. First, we determine the unique tree whose complement has minimum (respectively, maximum) $\mathcal{E}$-spectral radius among the complements of trees. Then, we prove that the $\mathcal{E}$-eigenvalues of the complement of a tree are symmetric about the origin. As a consequence of these results, we characterize the trees whose complement has minimum (respectively, maximum) least $\mathcal{E}$-eigenvalues among the complements of trees. Finally, we discuss the extremal problems for the second largest $\mathcal{E}$-eigenvalue and the $\mathcal{E}$-energy of complements of trees and characterize the extremal graphs. As an application, we obtain a Nordhaus-Gaddum type lower bounds for the second largest $\mathcal{E}$-eigenvalue and $\mathcal{E}$-energy of a tree and its complement., Comment: 18 pages. Preliminary version
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- 2023
8. Numerical computation of cut off wave number in polygonal wave guide by eight node finite element mesh generation approach
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K. T. Shivaram, A. M. Yogitha, S. M. Rajesh, and N. Mahesh Kumar
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Physics ,QC1-999 - Abstract
This study proposes a two-dimensional, eight-noded automated mesh generator for precise and efficient finite element analysis (FEA) in microwave applications. The suggested method for solving the Helmholtz problem employs an optimal domain discretization procedure. MAPLE-13 software's advanced automatic mesh generator was developed specifically for this work. To demonstrate the effectiveness of the approach, three distinct waveguide structures are analyzed, with the results compared to the best available analytical or numerical solutions. The findings indicate that the proposed method yields highly accurate and efficient finite element results, particularly for waveguide structures containing singularities. In microwave applications, this method can significantly enhance energy transmission efficiency.
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- 2024
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9. Indentation Fracture Toughness of Aluminium-Graphite Composites: Influence of Nano-particles
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Ibrahim Alqahtani, B. Niyaz Ahmed, E. Ashoka, A. M. Rajesh, P. B. Bharath, and Doddamani Saleemsab
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Indentation ,Nanocomposite ,Graphite Nanoparticles ,Al6061 ,Fracture Toughness ,Mechanical engineering and machinery ,TJ1-1570 ,Structural engineering (General) ,TA630-695 - Abstract
In the field of composite materials, extensive research has been undertaken on aluminum-graphite composites. However, a research gap has been identified regarding the specific influence of nano-sized graphite particles on their fracture toughness. Previous studies have predominantly focused on larger graphite particles or different reinforcement materials, resulting in relatively unexplored effects of nano-graphite particles. This research is deemed critical as it has the potential to generate lightweight, high-strength materials, aligning with the demands of aerospace, automotive, and structural engineering. The primary objective of this study is to investigate how the inclusion of nano-sized graphite particles affects the fracture toughness of aluminum-graphite composites. To achieve this objective, systematic dispersion and incorporation of nano-sized graphite particles into an aluminum matrix will be carried out. Mechanical testing, including fracture toughness assessments, will be conducted to evaluate the performance of the composite materials. Factors such as particle size, distribution, volume fraction, and interfacial bonding will also be characterized within the study. It is anticipated that the presence of nano-sized graphite particles will lead to a significant enhancement of the fracture toughness of the aluminum-graphite nanocomposites. This enhancement is expected to be attributed to crack deflection, tortuosity, altered stress distribution, and increased plastic deformation around cracks.
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- 2024
10. Minimizers for the energy of eccentricity matrices of trees
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Mahato, Iswar and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
The eccentricity matrix of a connected graph $G$, denoted by $\mathcal{E}(G)$, is obtained from the distance matrix of $G$ by keeping the largest nonzero entries in each row and each column and leaving zeros in the remaining ones. The eigenvalues of $\mathcal{E}(G)$ are the $\mathcal{E}$-eigenvalues of $G$. The eccentricity energy (or the $\mathcal{E}$-energy) of $G$ is the sum of the absolute values of all $\mathcal{E}$-eigenvalues of $G$. In this article, we determine the unique tree with the minimum second largest $\mathcal{E}$-eigenvalue among all trees on $n$ vertices other than the star. Also, we characterize the trees with minimum $\mathcal{E}$-energy among all trees on $n$ vertices., Comment: 18 Pages
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- 2022
11. Squared distance matrices of trees with matrix weights
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Mahato, Iswar and Kannan, M. Rajesh
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Mathematics - Combinatorics ,05C22, 05C50 - Abstract
Let $T$ be a tree on $n$ vertices whose edge weights are positive definite matrices of order $s$. The squared distance matrix of $T$, denoted by $\Delta$, is the $ns \times ns$ block matrix with $\Delta_{ij}=d(i,j)^2$, where $d(i,j)$ is the sum of the weights of the edges in the unique $(i,j)$-path. In this article, we obtain a formula for the determinant of $\Delta$ and find ${\Delta}^{-1}$ under some conditions., Comment: Preliminary version. Comments are welcome. 17 pages
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- 2022
12. Signed spectral Tura\'{n} type theorems
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Kannan, M. Rajesh and Pragada, Shivaramakrishna
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Mathematics - Combinatorics ,05C22, 05C50 - Abstract
A signed graph $\Sigma = (G, \sigma)$ is a graph where the function $\sigma$ assigns either $1$ or $-1$ to each edge of the simple graph $G$. The adjacency matrix of $\Sigma$, denoted by $A(\Sigma)$, is defined canonically. In a recent paper, Wang et al. extended the eigenvalue bounds of Hoffman and Cvetkovi\'{c} for the signed graphs. They proposed an open problem related to the balanced clique number and the largest eigenvalue of a signed graph. We solve a strengthened version of this open problem. As a byproduct, we give alternate proofs for some of the known classical bounds for the least eigenvalues of the unsigned graphs. We extend the Tur\'{a}n's inequality for the signed graphs. Besides, we study the Bollob\'{a}s and Nikiforov conjecture for the signed graphs and show that the conjecture need not be true for the signed graphs. Nevertheless, the conjecture holds for signed graphs under some assumptions. Finally, we study some of the relationships between the number of signed walks and the largest eigenvalue of a signed graph., Comment: Updated version. Title is changed. Typos are fixed
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- 2022
13. On the eccentricity matrices of trees: Inertia and spectral symmetry
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Mahato, Iswar and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
The \textit{eccentricity matrix} $\mathcal{E}(G)$ of a connected graph $G$ is obtained from the distance matrix of $G$ by keeping the largest non-zero entries in each row and each column, and leaving zeros in the remaining ones. The eigenvalues of $\mathcal{E}(G)$ are the \textit{$\mathcal{E}$-eigenvalues} of $G$. In this article, we find the inertia of the eccentricity matrices of trees. Interestingly, any tree on more than $4$ vertices with odd diameter has two positive and two negative $\mathcal{E}$-eigenvalues (irrespective of the structure of the tree). A tree with even diameter has the same number of positive and negative $\mathcal{E}$-eigenvalues, which is equal to the number of 'diametrically distinguished' vertices (see Definition 3.1). Besides we prove that the spectrum of the eccentricity matrix of a tree is symmetric with respect to the origin if and only if the tree has odd diameter. As an application, we characterize the trees with three distinct $\mathcal{E}$-eigenvalues., Comment: Some of the typos are fixed. Comments are welcome!
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- 2022
14. Design of Solid State Tesla Coil With Music Playback Functionality
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Naman Tanwar, M. Rajesh Kumar, and Rani Chinnappa Naidu
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Tesla coil ,SSTC ,IGBT ,gate drive transformer (GDT) ,feedback control ,NE555 ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper presents the design, simulation, and implementation of a solid state Tesla coil (SSTC) with music playback functionality through its arcs. It showcases various circuit designs that explore both feedback and non-feedback-based control mechanisms. The non-feedback based mechanism relies on an external oscillator circuit based on NE555 timer IC to drive the Tesla transformer coil at its resonance and the feedback based system relies on the selective amplification of a certain frequency at which the secondary coil is self-resonant. Additionally, to produce tones from the Tesla coil’s arcs, this paper implements a fixed gate signal interrupter circuit design that produces specific tones, as well as a music-based gate signal interrupter circuit design that produces music from the arcs. To verify the functionality of the design, the designed circuits were simulated in the LTspice SPICE simulation software and then implemented on a prototype board followed by a four-layer printed circuit board implementation. The primary coil of the Tesla transformer was controlled using an insulated-gate bipolar transistor (IGBT) based half bridge circuit.
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- 2024
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15. StarPlat: A versatile DSL for graph analytics
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Behera, Nibedita, Kumar, Ashwina, Rajadurai T, Ebenezer, Nitish, Sai, M, Rajesh Pandian, and Nasre, Rupesh
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- 2024
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16. On the construction of cospectral nonisomorphic bipartite graphs
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Kannan, M. Rajesh, Pragada, Shivaramakrishna, and Wankhede, Hitesh
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Mathematics - Combinatorics - Abstract
In this article, we construct bipartite graphs which are cospectral for both the adjacency and normalized Laplacian matrices using partitioned tensor product. This extends the construction of Ji, Gong, and Wang \cite{ji-gong-wang}. Our proof of the cospectrality of adjacency matrices simplifies the proof of the bipartite case of Godsil and McKay's construction \cite{godsil-mckay-1976}, and shows that the corresponding normalized Laplacian matrices are also cospectral. We partially characterize the isomorphism in Godsil and McKay's construction, and generalize Ji et al.'s characterization of the isomorphism to biregular bipartite graphs. The essential idea in characterizing the isomorphism uses Hammack's cancellation law as opposed to Hall's marriage theorem used by Ji et al., Comment: 13 pages
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- 2021
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17. Geometric trust-based secure localization technique for resiliency of GPS outage and location error in vehicular cyber-physical systems (VCPS)
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N, Nithiyanandam, M, Rajesh, Ramachandran, Sitharthan, K, Vengatesan, A, Mohamed Imran, C, Dhanamjayulu, and Khan, Baseem
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- 2023
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18. Performance of little millet (Panicum flexuosum) based cropping system for rainfed agro ecosystems: A path to sustainable crop diversification
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K SIVAGAMY, BALAJI PARASURAMAN, S ARUL PRASAD, K ANANTHI, M RAJESH, K SHARMILI, V KARUNAKARAN, AJAY KUMAR, and A SELVARANI
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Crop diversification, Economic return, Inter cropping, Little millet, Nutritional security, Pulses ,Agriculture - Abstract
An experiment was conducted during 2019, 2020 and 2021 at Centre of Excellence in Millets, (Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu), Athiyandal, Tiruvanamalai, Tamil Nadu. to study the performance of little millet (Panicum flexuosum Retz.) based cropping system for rainfed agro ecosystems for north-eastern part of Tamil Nadu. The experiment was laid out in randomized block design (RBD) comprised of 9 treatments, viz. T1, Little millet + Redgram [Cajanus cajan (L.) Millsp.] (4:1)-Moth bean [Vigna aconitifolia (Jacq.) Marechal]; T2, Little millet + Redgram (4:1)-Blackgram [Vigna mungo (L.) Hepper]; T3, Little millet + Redgram (4:1)-Horsegram [Macrotyloma uniflorum (Lam.) Verdc.]; T4, Little millet + Redgram (6:2)-Moth bean; T5, Little millet + Redgram (6:2)-Blackgram; T6, Little millet + Redgram (6:2)-Horsegram; T7, Little millet + Redgram (8:2)- Mothbean; T8, Little millet + Redgram (8:2)-Blackgram; T9, Little millet + Redgram (8:2)- Horsegram, with three replications. The good quality seeds of little millet (CO 4), redgram (Paiyur 2), horsegram (Paiyur 2), blackgram (VBN 3) and mothbean [TMV (Mb) 1] were used. The result shows that the higher yield for little millet and intercropped redgram was recorded in T9 (985 and 362 kg/ha) followed by T7 (853 and 356 kg/ha) and T8 (834 and 337 kg/ ha). The 8:2 row ratio exhibited the highest little millet equivalent yield when compared to 6:2 and 4:1 row ratio. The highest economic return and benefit cost (B:C) ratio was observed in T9 with gross return of ₹60,962/ha, net returns of ₹35,362/ha and B:C ratio (2.38). This was followed by T7 which had gross returns of ₹51,314/ha, net returns of ₹25,989/ha and B:C ratio (2.10).
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- 2024
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19. Eccentricity energy change of complete multipartite graphs due to edge deletion
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Mahato, Iswar and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
The eccentricity matrix $\varepsilon(G)$ of a graph $G$ is obtained from the distance matrix of $G$ by retaining the largest distances in each row and each column, and leaving zeros in the remaining ones. The eccentricity energy of $G$ is sum of the absolute values of the eigenvalues of $\varepsilon(G)$. Although the eccentricity matrices of graphs are closely related to the distance matrices of graphs, a number of properties of eccentricity matrices are substantially different from those of the distance matrices. The change in eccentricity energy of a graph due to an edge deletion is one such property. In this article, we give examples of graphs for which the eccentricity energy increase (resp., decrease) but the distance energy decrease (resp., increase) due to an edge deletion. Also, we prove that the eccentricity energy of the complete $k$-partite graph $K_{n_1,\hdots,n_k}$ with $k\geq 2$ and $ n_i\geq 2$, increases due to an edge deletion., Comment: Preliminary version. 11 pages
- Published
- 2021
20. Investigation of impact energy absorption of AA6061 and its composites: role of post-aging cooling methods
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G. V. Krishna Reddy, B. K. Naveen Kumar, G. Hareesha, A. M. Rajesh, and Saleemsab Doddamani
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metal matrix composite ,al-graphite composite ,impact energy ,al-sic ,post-ageing cooling ,Mechanical engineering and machinery ,TJ1-1570 ,Structural engineering (General) ,TA630-695 - Abstract
Al6061 and its composites are widely employed in applications requiring high strength and impact resistance. Heat treatment, particularly ageing, is a well-established method for enhancing the mechanical properties of these composites. However, the influence of post-ageing cooling methods on the impact energy absorption capacity of Al6061 and its composites is not well understood. This investigation aims to examine the impact energy absorption of Al6061 and its composites after ageing at 460�C for 2 hours, employing different cooling methods, including furnace cooling, air cooling, and water cooling. The composites were produced using the stir casting technique with varying weight fractions of graphite and SiC particles based on Taguchi's design of experiments. Charpy impact tests were conducted using a specialised testing machine. The results reveal that the impact energy absorption capacity of the composites is influenced by the cooling method used after the ageing treatment. Furnace cooling demonstrated the highest impact energy absorption capacity compared to the other cooling methods, exhibiting a 28% increase relative to the monolithic aluminium alloy. Furthermore, it was observed that the impact energy absorption capacity of the composites did not improve with an increase in the weight fraction of SiC particles, while the addition of graphite negatively impacted the absorption capacity
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- 2023
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21. Bounds for the extremal eigenvalues of gain Laplacian matrices
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Kannan, M. Rajesh, Kumar, Navish, and Pragada, Shivaramakrishna
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Mathematics - Combinatorics ,05C22(primary), 05C50(secondary) - Abstract
A complex unit gain graph ($\mathbb{T}$-gain graph), $\Phi = (G, \varphi)$ is a graph where the function $\varphi$ assigns a unit complex number to each orientation of an edge of $G$, and its inverse is assigned to the opposite orientation. A $ \mathbb{T} $-gain graph $\Phi$ is balanced if the product of the edge gains of each cycle (with a fixed orientation) is $1$. Signed graphs are special cases of $\mathbb{T}$-gain graphs. The adjacency matrix of $\Phi$, denoted by $ \mathbf{A}(\Phi)$ is defined canonically. The gain Laplacian for $\Phi$ is defined as $\mathbf{L}(\Phi) = \mathbf{D}(\Phi) - \mathbf{A}(\Phi)$, where $\mathbf{D}(\Phi)$ is the diagonal matrix with diagonal entries are the degrees of the vertices of $G$. The minimum number of vertices (resp., edges) to be deleted from $\Phi$ in order to get a balanced gain graph the frustration number (resp, frustration index). We show that frustration number and frustration index are bounded below by the smallest eigenvalue of $\mathbf{L}(\Phi)$. We provide several lower and upper bounds for extremal eigenvalues of $\mathbf{L}(\Phi)$ in terms of different graph parameters such as the number of edges, vertex degrees, and average $2$-degrees. The signed graphs are particular cases of the $\mathbb{T}$-gain graphs, all the bounds established in paper hold for signed graphs. Most of the bounds established here are new for signed graphs. Finally, we perform comparative analysis for all the obtained bounds in the paper with the state-of-the-art bounds available in the literature for randomly generated Erd\H{o}s-Re\'yni graphs. Some of the major highlights of our paper are the gain-dependent bounds, limit convergence of the bounds to the extremal eigenvalues, and optimal extremal bounds obtained by posing optimization problems to achieve the best possible bounds., Comment: Preliminary version. 32 pages
- Published
- 2021
22. Gain distance matrices for complex unit gain graphs
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Samanta, Aniruddha and Kannan, M. Rajesh
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Mathematics - Combinatorics - Abstract
A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $, and its inverse is assigned to the opposite orientation. %A complex unit gain graph($ \mathbb{T} $-gain graph) is a simple graph where each orientation of an edge is given a complex unit, and its inverse is assigned to the opposite orientation of the edge. In this article, we propose gain distance matrices for $ \mathbb{T} $-gain graphs. These notions generalize the corresponding known concepts of distance matrices and signed distance matrices. Shahul K. Hameed et al. introduced signed distance matrices and developed their properties. Motivated by their work, we establish several spectral properties, including some equivalences between balanced $ \mathbb{T} $-gain graphs and gain distance matrices. Furthermore, we introduce the notion of positively weighted $ \mathbb{T} $-gain graphs and study some of their properties. Using these properties, Acharya's and Stani\'c's spectral criteria for balance are deduced. Moreover, the notions of order independence and distance compatibility are studied. Besides, we obtain some characterizations for distance compatibility., Comment: 20 pages; 2 figures
- Published
- 2021
23. On the multiplicity of $A{\alpha}$-eigenvalues and the rank of complex unit gain graphs
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Samanta, Aniruddha and Kannan, M. Rajesh
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Mathematics - Combinatorics ,05C50, 05C22, 05C35 - Abstract
Let $ \Phi=(G, \varphi) $ be a connected complex unit gain graph ($ \mathbb{T} $-gain graph) on a simple graph $ G $ with $ n $ vertices and maximum vertex degree $ \Delta $. The associated adjacency matrix and degree matrix are denoted by $ A(\Phi) $ and $ D(\Phi) $, respectively. Let $ m_{\alpha}(\Phi,\lambda) $ be the multiplicity of $ \lambda $ as an eigenvalue of $ A_{\alpha}(\Phi) :=\alpha D(\Phi)+(1-\alpha)A(\Phi)$, for $ \alpha\in[0,1) $. In this article, we establish that $ m_{\alpha}(\Phi, \lambda)\leq \frac{(\Delta-2)n+2}{\Delta-1}$, and characterize the classes of graphs for which the equality hold. Furthermore, we establish a couple of bounds for the rank of $A(\Phi)$ in terms of the maximum vertex degree and the number of vertices. One of the main results extends a result known for unweighted graphs and simplifies the proof in [15], and other results provide better bounds for $r(\Phi)$ than the bounds known in [8].
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- 2021
24. Ammonothermal Crystal Growth of Functional Nitrides for Semiconductor Devices: Status and Potential
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Thomas Wostatek, V. Y. M. Rajesh Chirala, Nathan Stoddard, Ege N. Civas, Siddha Pimputkar, and Saskia Schimmel
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ammonothermal ,synthesis ,nitrides ,semiconductors ,solubility ,in situ monitoring ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
The state-of-the-art ammonothermal method for the growth of nitrides is reviewed here, with an emphasis on binary and ternary nitrides beyond GaN. A wide range of relevant aspects are covered, from fundamental autoclave technology, to reactivity and solubility of elements, to synthesized crystalline nitride materials and their properties. Initially, the potential of emerging and novel nitrides is discussed, motivating their synthesis in single crystal form. This is followed by a summary of our current understanding of the reactivity/solubility of species and the state-of-the-art single crystal synthesis for GaN, AlN, AlGaN, BN, InN, and, more generally, ternary and higher order nitrides. Investigation of the synthesized materials is presented, with a focus on point defects (impurities, native defects including hydrogenated vacancies) based on GaN and potential pathways for their mitigation or circumvention for achieving a wide range of controllable functional and structural material properties. Lastly, recent developments in autoclave technology are reviewed, based on GaN, with a focus on advances in development of in situ technologies, including in situ temperature measurements, optical absorption via UV/Vis spectroscopy, imaging of the solution and crystals via optical (visible, X-ray), along with use of X-ray computed tomography and diffraction. While time intensive to develop, these technologies are now capable of offering unprecedented insight into the autoclave and, hence, facilitating the rapid exploration of novel nitride synthesis using the ammonothermal method.
- Published
- 2024
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25. Squared distance matrices of trees with matrix weights
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Iswar Mahato and M. Rajesh Kannan
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Tree ,distance matrix ,squared distance matrix ,matrix weight ,determinant ,inverse ,Mathematics ,QA1-939 - Abstract
AbstractLet T be a tree on n vertices whose edge weights are positive definite matrices of order s. The squared distance matrix of T, denoted by Δ, is the ns × ns block matrix with [Formula: see text], where d(i, j) is the sum of the weights of the edges in the unique (i, j)-path. In this article, we obtain a formula for the determinant of Δ and find [Formula: see text] under some conditions.
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- 2023
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26. Normalized Laplacians for Gain Graphs
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Kannan, M. Rajesh, Kumar, Navish, and Pragada, Shivaramakrishna
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Mathematics - Combinatorics - Abstract
We propose the notion of normalized Laplacian matrix $\mathcal{L}(\Phi)$ for a gain graphs and study its properties in detail, providing insights and counterexamples along the way. We establish bounds for the eigenvalues of $\mathcal{L}(\Phi)$ and characterize the classes of graphs for which equality holds. The relationships between the balancedness, bipartiteness, and their connection to the spectrum of $\mathcal{L}(\Phi)$ are also studied. Besides, we extend the edge version of eigenvalue interlacing for the gain graphs. Thereupon, we determine the coefficients for the characteristic polynomial of $\mathcal{L}(\Phi)$., Comment: 20 Pages
- Published
- 2020
27. Interval hulls of $N$-matrices and almost $P$-matrices
- Author
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Choudhury, Projesh Nath and Kannan, M. Rajesh
- Subjects
Mathematics - Rings and Algebras ,Mathematics - Numerical Analysis ,15B48, 15A24, 65G30 - Abstract
We establish a characterization of almost $P$-matrices via a sign non-reversal property. In this we are inspired by the analogous results for $N$-matrices. Next, the interval hull of two $m \times n$ matrices $A=(a_{ij})$ and $B = (b_{ij})$, denoted by $\mathbb{I}(A,B)$, is the collection of all matrices $C \in \mathbb{R}^{m \times n}$ such that each $c_{ij}$ is a convex combination of $a_{ij}$ and $b_{ij}$. Using the sign non-reversal property, we identify a finite subset of $\mathbb{I}(A,B)$ that determines if all matrices in $\mathbb{I}(A,B)$ are $N$-matrices/almost $P$-matrices. This provides a test for an entire class of matrices simultaneously to be $N$-matrices/almost $P$-matrices. We also establish analogous results for semipositive and minimally semipositive matrices. These characterizations may be considered similar in spirit to that of $P$-matrices by Bialas-Garloff [Linear Algebra Appl. 1984] and Rohn-Rex [SIMAX 1996], and of positive definite matrices by Rohn [SIMAX 1994].
- Published
- 2020
28. On the $A_{\alpha}$-spectra of some join graphs
- Author
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Basunia, Mainak, Mahato, Iswar, and Kannan, M. Rajesh
- Subjects
Mathematics - Combinatorics ,05C50, 05C05 - Abstract
Let $G$ be a simple, connected graph and let $A(G)$ be the adjacency matrix of $G$. If $D(G)$ is the diagonal matrix of the vertex degrees of $G$, then for every real $\alpha \in [0,1]$, the matrix $A_{\alpha}(G)$ is defined as $$A_{\alpha}(G) = \alpha D(G) + (1- \alpha) A(G).$$ The eigenvalues of the matrix $A_{\alpha}(G)$ form the $A_{\alpha}$-spectrum of $G$. Let $G_1 \dot{\vee} G_2$, $G_1 \underline{\vee} G_2$, $G_1 \langle \textrm{v} \rangle G_2$ and $G_1 \langle \textrm{e} \rangle G_2$ denote the subdivision-vertex join, subdivision-edge join, $R$-vertex join and $R$-edge join of two graphs $G_1$ and $G_2$, respectively. In this paper, we compute the $A_{\alpha}$-spectra of $G_1 \dot{\vee} G_2$, $G_1 \underline{\vee} G_2$, $G_1 \langle \textrm{v} \rangle G_2$ and $G_1 \langle \textrm{e} \rangle G_2$ for a regular graph $G_1$ and an arbitrary graph $G_2$ in terms of their $A_{\alpha}$-eigenvalues. As an application of these results, we construct infinitely many pairs of $A_{\alpha}$-cospectral graphs.
- Published
- 2020
29. Sign non-reversal property for totally non-negative and totally positive matrices, and testing total positivity of their interval hull
- Author
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Choudhury, Projesh Nath, Kannan, M. Rajesh, and Khare, Apoorva
- Subjects
Mathematics - Rings and Algebras ,Mathematics - Numerical Analysis ,15B48 (primary), 15A24, 65G30 (secondary) - Abstract
A matrix $A$ is totally positive (or non-negative) of order $k$, denoted $TP_k$ (or $TN_k$), if all minors of size $\leq k$ are positive (or non-negative). It is well-known that such matrices are characterized by the variation diminishing property together with the sign non-reversal property. We do away with the former, and show that $A$ is $TP_k$ if and only if every submatrix formed from at most $k$ consecutive rows and columns has the sign non-reversal property. In fact this can be strengthened to only consider test vectors in $\mathbb{R}^k$ with alternating signs. We also show a similar characterization for all $TN_k$ matrices - more strongly, both of these characterizations use a single vector (with alternating signs) for each square submatrix. These characterizations are novel, and similar in spirit to the fundamental results characterizing $TP$ matrices by Gantmacher-Krein [Compos. Math. 1937] and $P$-matrices by Gale-Nikaido [Math. Ann. 1965]. As an application, we study the interval hull $\mathbb{I}(A,B)$ of two $m \times n$ matrices $A=(a_{ij})$ and $B = (b_{ij})$. This is the collection of $C \in \mathbb{R}^{m \times n}$ such that each $c_{ij}$ is between $a_{ij}$ and $b_{ij}$. Using the sign non-reversal property, we identify a two-element subset of $\mathbb{I}(A,B)$ that detects the $TP_k$ property for all of $\mathbb{I}(A,B)$ for arbitrary $k \geq 1$. In particular, this provides a test for total positivity (of any order), simultaneously for an entire class of rectangular matrices. In parallel, we also provide a finite set to test the total non-negativity (of any order) of an interval hull $\mathbb{I}(A,B)$., Comment: Final version, to appear in Bulletin of the London Mathematical Society. 9 pages, no figures
- Published
- 2020
- Full Text
- View/download PDF
30. Complex Wavelet SSIM based Image Data Augmentation
- Author
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Raveendran, Ritin, Singh, Aviral, and M, Rajesh Kumar
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
One of the biggest problems in neural learning networks is the lack of training data available to train the network. Data augmentation techniques over the past few years, have therefore been developed, aiming to increase the amount of artificial training data with the limited number of real world samples. In this paper, we look particularly at the MNIST handwritten dataset an image dataset used for digit recognition, and the methods of data augmentation done on this data set. We then take a detailed look into one of the most popular augmentation techniques used for this data set elastic deformation; and highlight its demerit of degradation in the quality of data, which introduces irrelevant data to the training set. To decrease this irrelevancy, we propose to use a similarity measure called Complex Wavelet Structural Similarity Index Measure (CWSSIM) to selectively filter out the irrelevant data before we augment the data set. We compare our observations with the existing augmentation technique and find our proposed method works yields better results than the existing technique.
- Published
- 2020
31. Bounds for a solution set of linear complementarity problems over Hilbert spaces
- Author
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Choudhury, Projesh Nath, Kannan, M. Rajesh, and Sivakumar, K. C.
- Subjects
Mathematics - Functional Analysis ,47A99, 90C48 - Abstract
Let $H$ be a real Hilbert space. In this short note, using some of the properties of bounded linear operators with closed range defined on $H$, certain bounds for a specific convex subset of the solution set of infinite linear complementarity problems, are established.
- Published
- 2020
32. Bounds for the energy of a complex unit gain graph
- Author
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Samanta, Aniruddha and Kannan, M. Rajesh
- Subjects
Mathematics - Combinatorics ,Mathematics - Spectral Theory ,05C50, 05C22, 05C35 - Abstract
A $\mathbb{T}$-gain graph, $\Phi = (G, \varphi)$, is a graph in which the function $\varphi$ assigns a unit complex number to each orientation of an edge, and its inverse is assigned to the opposite orientation. The associated adjacency matrix $ A(\Phi) $ is defined canonically. The energy $ \mathcal{E}(\Phi) $ of a $ \mathbb{T} $-gain graph $ \Phi $ is the sum of the absolute values of all eigenvalues of $ A(\Phi) $. We study the notion of energy of a vertex of a $ \mathbb{T} $-gain graph, and establish bounds for it. For any $ \mathbb{T} $-gain graph $ \Phi$, we prove that $2\tau(G)-2c(G) \leq \mathcal{E}(\Phi) \leq 2\tau(G)\sqrt{\Delta(G)}$, where $ \tau(G), c(G)$ and $ \Delta(G)$ are the vertex cover number, the number of odd cycles and the largest vertex degree of $ G $, respectively. Furthermore, using the properties of vertex energy, we characterize the classes of $ \mathbb{T} $-gain graphs for which $ \mathcal{E}(\Phi)=2\tau(G)-2c(G) $ holds. Also, we characterize the classes of $ \mathbb{T} $-gain graphs for which $\mathcal{E}(\Phi)= 2\tau(G)\sqrt{\Delta(G)} $ holds. This characterization solves a general version of an open problem. In addition, we establish bounds for the energy in terms of the spectral radius of the associated adjacency matrix., Comment: 31 pages, 4 figures
- Published
- 2020
33. On dense subsets of matrices with distinct eigenvalues and distinct singular values
- Author
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Das, Himadri Lal and Kannan, M. Rajesh
- Subjects
Mathematics - Functional Analysis ,15A15, 15A18 - Abstract
It is well known that the set of all $ n \times n $ matrices with distinct eigenvalues is a dense subset of the set of all real or complex $ n \times n $ matrices. In [Hartfiel, D. J. Dense sets of diagonalizable matrices. Proc. Amer. Math. Soc., 123(6): 1669-1672, 1995.], the author established a necessary and sufficient condition for a subspace of the set of all $n \times n$ matrices to have a dense subset of matrices with distinct eigenvalues. We are interested in finding a few necessary and sufficient conditions for a subset of the set of all $n \times n$ real or complex matrices to have a dense subset of matrices with distinct eigenvalues. Some of our results are generalizing the results of Hartfiel. Also, we study the existence of dense subsets of matrices with distinct singular values, distinct analytic eigenvalues, and distinct analytic singular values, respectively, in the subsets of the set of all real or complex matrices., Comment: 20 pages
- Published
- 2020
34. On the construction of cospectral graphs for the adjacency and normalized Laplacian matrices
- Author
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Kannan, M. Rajesh and Pragada, Shivaramakrishna
- Subjects
Mathematics - Combinatorics ,05C50 - Abstract
In [Steve Butler. A note about cospectral graphs for the adjacency and normalized Laplacian matrices. Linear Multilinear Algebra, 58(3-4):387-390, 2010.], Butler constructed a family of bipartite graphs, which are cospectral for both the adjacency and the normalized Laplacian matrices. In this article, we extend this construction for generating larger classes of bipartite graphs, which are cospectral for both the adjacency and the normalized Laplacian matrices. Also, we provide a couple of constructions of non-bipartite graphs, which are cospectral for the adjacency matrices but not necessarily for the normalized Laplacian matrices.
- Published
- 2020
35. OMAP-L138 LCDK Development Kit
- Author
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P, Bharath K, K, Sylash, K, Pravina, and M, Rajesh Kumar
- Subjects
Electrical Engineering and Systems Science - Audio and Speech Processing ,Computer Science - Sound - Abstract
Low cost and low power consumption processor play a vital role in the field of Digital Signal Processing (DSP). The OMAP-L138 development kit which is low cost, low power consumption, ease and speed, with a wide variety of applications includes Digital signal processing, Image processing and video processing. This paper represents the basic introduction to OMAP-L138 processor and quick procedural steps for real time and non-real time implementations with a set of programs. The real time experiments are based on audio in the applications of audio loopback, delay and echo. Whereas the non-real time experiments are generation of a sine wave, low pass and high pass filter.
- Published
- 2020
36. Data hiding in speech signal using steganography and encryption
- Author
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N, Hanisha Chowdary, K, Karan, P, Bharath K, and M, Rajesh Kumar
- Subjects
Computer Science - Multimedia - Abstract
Data privacy and data security are always on highest priority in the world. We need a reliable method to encrypt the data so that it reaches the destination safely. Encryption is a simple yet effective way to protect our data while transmitting it to a destination. The proposed method has state of art technology of steganography and encryption. This paper puts forward a different approach for data hiding in speech signals. A ten-digit number within speech signal using audio steganography and encrypting it with a unique key for better security. At the receiver end the same unique key is used to decrypt the received signal and then hidden numbers are extracted. The proposed approach performance can be evaluated by PSNR, MSE, SSIM and bit-error rate. The simulation results give better performance compared to existing approach.
- Published
- 2020
37. Radial Based Analysis of GRNN in Non-Textured Image Inpainting
- Author
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R, Karthik, Dwivedi, Anvita, M, Haripriya, P, Bharath K, and M, Rajesh Kumar
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Image inpainting algorithms are used to restore some damaged or missing information region of an image based on the surrounding information. The method proposed in this paper applies the radial based analysis of image inpainting on GRNN. The damaged areas are first isolated from rest of the areas and then arranged by their size and then inpainted using GRNN. The training of the neural network is done using different radii to achieve a better outcome. A comparative analysis is done for different regression-based algorithms. The overall results are compared with the results achieved by the other algorithms as LS-SVM with reference to the PSNR value.
- Published
- 2020
38. Handwritten Character Recognition Using Unique Feature Extraction Technique
- Author
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Ayyadevara, Sai Abhishikth, Teja, P N V Sai Ram, P, Bharath K, and M, Rajesh Kumar
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
One of the most arduous and captivating domains under image processing is handwritten character recognition. In this paper we have proposed a feature extraction technique which is a combination of unique features of geometric, zone-based hybrid, gradient features extraction approaches and three different neural networks namely the Multilayer Perceptron network using Backpropagation algorithm (MLP BP), the Multilayer Perceptron network using Levenberg-Marquardt algorithm (MLP LM) and the Convolutional neural network (CNN) which have been implemented along with the Minimum Distance Classifier (MDC). The procedures lead to the conclusion that the proposed feature extraction algorithm is more accurate than its individual counterparts and also that Convolutional Neural Network is the most efficient neural network of the three in consideration.
- Published
- 2020
39. Optimal placement of time-varying distributed generators by using crow search and black widow - Hybrid optimization
- Author
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Vempalle Rafi, P.K. Dhal, M. Rajesh, D.R. Srinivasan, M. Chandrashekhar, and N. Madhava Reddy
- Subjects
Distributed generation resources (DGRs) ,Reorganization ,Optimal location ,Crow search ,Black widow optimization ,Electric apparatus and materials. Electric circuits. Electric networks ,TK452-454.4 - Abstract
This paper focuses on the optimal reorganization of radial distribution system (RDS) and the superlative location of time-varying power generation distributed generators, considering time-varying loads. The electric generators, utilizing non-conventional energy sources, are directly connected to the distribution grids with lower ratings compared to conventional source-driven generators. In this study, a combination of optimization techniques, such as the black widow and crow search techniques, is employed to enhance performance in terms of optimal reorganization and superlative location of distribution generation. The reorganization problem is examined and analyzed by considering various scenarios in a standard 69-bus grid, as well as in larger-scale 119-bus and 135-bus systems, with and without the presence of distributed generation resources. The analysis of the proposed optimization techniques with the obtained results is well discussed in this paper.
- Published
- 2023
- Full Text
- View/download PDF
40. On the eigenvalue region of permutative doubly stochastic matrices
- Author
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Mandal, Amrita, Adhikari, Bibhas, and Kannan, M. Rajesh
- Subjects
Mathematics - Combinatorics ,15A18, 15A29, 15B51 - Abstract
This paper is devoted to the study of eigenvalue region of the doubly stochastic matrices which are also permutative, that is, each row of such a matrix is a permutation of any other row. We call these matrices as permutative doubly stochastic (PDS) matrices. A method is proposed to obtain symbolic representation of all PDS matrices of order $n$ by finding equivalence classes of permutationally similar symbolic PDS matrices. This is a hard problem in general as it boils down to finding all Latin squares of order $n.$ However, explicit symbolic representation of matrices in these classes are determined in this paper when $n=2, 3, 4.$ It is shown that eigenvalue regions are same for doubly stochastic matrices and PDS matrices when $n=2, 3.$ It is also established that this is no longer true for $n=4,$ and two line segments are determined which belong to the eigenvalue region of doubly stochastic matrices but not in the eigenvalue region of PDS matrices. Thus a conjecture is developed for the boundary of the eigenvalue region of PDS matrices of order $4.$ Finally, inclusion theorems for eigenvalue region of PDS matrices are proved when $n\geq 2.$, Comment: 37 pages, some new results are added, title is changed
- Published
- 2019
41. On the spectral radius and the energy of eccentricity matrix of a graph
- Author
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Mahato, Iswar, Gurusamy, R., Kannan, M. Rajesh, and Arockiaraj, S.
- Subjects
Mathematics - Combinatorics - Abstract
The eccentricity matrix $\varepsilon(G)$ of a graph $G$ is obtained from the distance matrix by retaining the eccentricities (the largest distance) in each row and each column. In this paper, we give a characterization of the star graph, among the trees, in terms of invertibility of the associated eccentricity matrix. The largest eigenvalue of $\varepsilon(G)$ is called the $\varepsilon$-spectral radius, and the eccentricity energy (or the $\varepsilon$-energy) of $G$ is the sum of the absolute values of the eigenvalues of $\varepsilon(G)$. We establish some bounds for the $\varepsilon$-spectral radius and characterize the extreme graphs. Two graphs are said to be $\varepsilon$-equienergetic if they have the same $\varepsilon$-energy. For any $n \geq 5$, we construct a pair of $\varepsilon$-equienergetic graphs on $n$ vertices, which are not $\varepsilon$-cospectral., Comment: 11 Pages
- Published
- 2019
42. On the spectrum of complex unit gain graph
- Author
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Samanta, Aniruddha and Kannan, M. Rajesh
- Subjects
Mathematics - Combinatorics - Abstract
A $\mathbb{T}$-gain graph is a simple graph in which a unit complex number is assigned to each orientation of an edge, and its inverse is assigned to the opposite orientation. The associated adjacency matrix is defined canonically, and is called $\mathbb{T}$-gain adjacency matrix. Let $\mathbb{T}_{G} $ denote the collection of all $\mathbb{T}$-gain adjacency matrices on a graph $G$. In this article, we study the cospectrality of matrices in $\mathbb{T}_{G} $ and we establish equivalent conditions for a graph $G$ to be a tree in terms of the spectrum and the spectral radius of matrices in $\mathbb{T}_{G} $. We identify a class of connected graphs $\mathfrak{F^{'}}$ such that for each $G \in \mathfrak{F^{'}}$, the matrices in $\mathbb{T}_G$ have nonnegative real part up to diagonal unitary similarity. Then we establish bounds for the spectral radius of $\mathbb{T}$-gain adjacency matrices on $ G \in \mathfrak{F^{'}} $ in terms of their largest eigenvalues. Thereupon, we characterize $\mathbb{T}$-gain graphs for which the spectral radius of the associated $\mathbb{T}$-gain adjacency matrices equal to the largest vertex degree of the underlying graph. These bounds generalize results known for the spectral radius of Hermitian adjacency matrices of digraphs and provide an alternate proof of a result about the sharpness of the bound in terms of largest vertex degree established in [Krystal Guo, Bojan Mohar. Hermitian adjacency matrix of digraphs and mixed graphs. J. Graph Theory 85 (2017), no. 1, 217-248.]., Comment: Comments are welcome!
- Published
- 2019
43. Spectra of eccentricity matrices of graphs
- Author
-
Mahato, Iswar, Gurusamy, R., Kannan, M. Rajesh, and Arockiaraj, S.
- Subjects
Mathematics - Combinatorics ,Mathematics - Spectral Theory ,05C12, 05C50 - Abstract
The eccentricity matrix of a connected graph $G$ is obtained from the distance matrix of $G$ by retaining the largest distances in each row and each column, and setting the remaining entries as $0$. In this article, a conjecture about the least eigenvalue of eccentricity matrices of trees, presented in the article [Jianfeng Wang, Mei Lu, Francesco Belardo, Milan Randic. The anti-adjacency matrix of a graph: Eccentricity matrix. Discrete Applied Mathematics, 251: 299-309, 2018.], is solved affirmatively. In addition to this, the spectra and the inertia of eccentricity matrices of various classes of graphs are investigated., Comment: Comments are welcome!
- Published
- 2019
- Full Text
- View/download PDF
44. Eigenvalue bounds for some classes of matrices associated with graphs
- Author
-
Mehatari, Ranjit and Kannan, M. Rajesh
- Subjects
Mathematics - Combinatorics ,Mathematics - Spectral Theory ,05C50 - Abstract
For a given complex square matrix $A$ with constant row sum, we establish two new eigenvalue inclusion sets. Using these bounds, first we derive bounds for the second largest and smallest eigenvalues of adjacency matrices of $k$-regular graphs. Then, we establish some bounds for the second largest and the smallest eigenvalues of the normalized adjacency matrices of graphs and the second smallest eigenvalue and the largest eigenvalue of the Laplacian matrices of graphs. Sharpness of these bounds are verified by examples., Comment: Comments are welcome!
- Published
- 2018
45. On the adjacency matrix of a complex unit gain graph
- Author
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Mehatari, Ranjit, Kannan, M. Rajesh, and Samanta, Aniruddha
- Subjects
Mathematics - Combinatorics ,05C50, 05C22 - Abstract
A complex unit gain graph is a simple graph in which each orientation of an edge is given a complex number with modulus 1 and its inverse is assigned to the opposite orientation of the edge. In this article, first we establish bounds for the eigenvalues of the complex unit gain graphs. Then we study some of the properties of the adjacency matrix of complex unit gain graph in connection with the characteristic and the permanental polynomials. Then we establish spectral properties of the adjacency matrices of complex unit gain graphs. In particular, using Perron-Frobenius theory, we establish a characterization for bipartite graphs in terms of the set of eigenvalues of gain graph and the set of eigenvalues of the underlying graph. Also, we derive an equivalent condition on the gain so that the eigenvalues of the gain graph and the eigenvalues of the underlying graph are the same., Comment: 14 pages, 2 figures
- Published
- 2018
46. ATL 1: A high yielding Kodo millet variety
- Author
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A. Nirmalakumari*, A. Subramanian, S. Geethanjali, R. Kanchanarani, P. Parasuraman, M. Jayachandran, R. Ravikesavan, M. Rajesh, K. Sivagamy, K. Ananthi, K. Sathiya, V. Manimozhi Selvi, B. Meenakumari, M. Madhanmohan, M. Gunasekaran, V. Ambetgar, S. Geetha, V. Geethalakhshmi, K. Prabakar, K. S. Subramanian
- Subjects
kodo ,varagu ,yield ,non lodging ,Plant culture ,SB1-1110 - Abstract
A high yielding, input responsive, non lodging varagu culture TNPsc 176 was developed at the Centre of Excellence in Millets, Athiyandal. It is a pure line selection from DPS 63. It is characterized by tufty and medium tall plant stature, strong and sturdy culm with regular, long panicles. It has 10-15 productive tillers/plant and non-shattering grains on the panicle. It matures in 105-110 days and has recorded 2506 and 4394 kg/ha of grain and straw yield, respectively in a total of 223 trials under rainfed conditions during the past eight years of evaluation at national and state levels. The yield was observed to be 12.5 and 13.8 per cent increase in terms of grain and 15.5 and 13.0 per cent increase in terms of straw over the check varieties, CO3 and TNAU 86, respectively. In view of the superior performance and desirable attributes viz., easy threshability, synchronized maturity, non-lodging growth habit, bold and attractive light brown-coloured grains with good nutritional and cooking qualities, the varagu culture TNPsc 176 was released as ATL 1 during the year 2021, for cultivation in Ariyalur, Cuddalore, Dharmapuri, Madurai, Perambalur, Pudukottai, Salem, Vellore, Villupuram and Virudhunagar districts of Tamil Nadu.
- Published
- 2022
- Full Text
- View/download PDF
47. Exploring the diversity of virulence genes in the Magnaporthe population infecting millets and rice in India
- Author
-
K. B. Palanna, H. D. Vinaykumar, S Koti. Prasanna, H. Rajashekara, B. N. Devanna, C. Anilkumar, B. Jeevan, H. R. Raveendra, Farooq Khan, C. H. Sai Bhavana, Vinod Upadhyay, T. S. S. K. Patro, Laxmi Rawat, M. Rajesh, P. T. Saravanan, Prahlad Netam, G. Rajesha, I. K. Das, H. E. Patil, A. K. Jain, S. Saralamma, S. Chandra Nayaka, G. Prakash, and T. E. Nagaraja
- Subjects
millet crops ,Magnaporthe ,virulent and avirulent genes ,blast pathogen ,PCR ,Plant culture ,SB1-1110 - Abstract
Blast pathogen, Magnaporthe spp., that infects ancient millet crops such pearl millet, finger millet, foxtail millet, barnyard millet, and rice was isolated from different locations of blast hotspots in India using single spore isolation technique and 136 pure isolates were established. Numerous growth characteristics were captured via morphogenesis analysis. Among the 10 investigated virulent genes, we could amplify MPS1 (TTK Protein Kinase) and Mlc (Myosin Regulatory Light Chain edc4) in majority of tested isolates, regardless of the crop and region where they were collected, indicating that these may be crucial for their virulence. Additionally, among the four avirulence (Avr) genes studied, Avr-Pizt had the highest frequency of occurrence, followed by Avr-Pia. It is noteworthy to mention that Avr-Pik was present in the least number of isolates (9) and was completely absent from the blast isolates from finger millet, foxtail millet, and barnyard millet. A comparison at the molecular level between virulent and avirulent isolates indicated observably large variation both across (44%) and within (56%) them. The 136 Magnaporthe spp isolates were divided into four groups using molecular markers. Regardless of their geographic distribution, host plants, or tissues affected, the data indicate that the prevalence of numerous pathotypes and virulence factors at the field level, which may lead to a high degree of pathogenic variation. This research could be used for the strategic deployment of resistant genes to develop blast disease-resistant cultivars in rice, pearl millet, finger millet, foxtail millet, and barnyard millet.
- Published
- 2023
- Full Text
- View/download PDF
48. The 3D Taper Profile Machining of Superalloys and Composites Using WEDM: A Review
- Author
-
Krishnamoorthy Jayakumar, T. Suresh, S. Senthur Vaishnavan, and M. Rajesh
- Subjects
three-dimensional profile machining ,superalloys and composites ,process parameter and responses ,Engineering machinery, tools, and implements ,TA213-215 - Abstract
Wire electric discharge machine (WEDM) is a process used popularly in microsystems, tool and die industries, medicine, transportation, and spacecrafts to create intricate portions with high dimensional accuracy and surface finish. It is employed to process superalloys and materials made of composites which are conductive and strong materials. From the literature, an analysis of the WEDM process on different materials revealed that there were many variables involved and that each process parameter influences the different response variables. The removal process of a spark discharge for an inclined angle during the cutting of 3D profiles has different applications. Also, types of dielectric fluid, and the influence of wire material, diameter and pressure, wire tension, feed, Ton, Toff, current, and voltage on machining characteristics—like kerf, MRR, wire wear, surface finish and its characteristics, dimensional deviations, and corner errors—and on a variety of materials like Inconel, nickel, titanium, WC, steels, and other superalloys and composites (MMCs and CMCs) during taper WEDM were reviewed.
- Published
- 2024
- Full Text
- View/download PDF
49. Type II fuzzy-based clustering with improved ant colony optimization-based routing (t2fcatr) protocol for secured data transmission in manet
- Author
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Nagendranth, M. V. S. S., Khanna, M. Rajesh, Krishnaraj, N., Sikkandar, Mohamed Yacin, Aboamer, Mohamed Abdelkader, and Surendran, R.
- Published
- 2022
- Full Text
- View/download PDF
50. Intensity and Rescale Invariant Copy Move Forgery Detection Techniques
- Author
-
K, Tejas, C, Swathi, and M, Rajesh Kumar
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
In this contemporary world digital media such as videos and images behave as an active medium to carry valuable information across the globe on all fronts. However there are several techniques evolved to tamper the image which has made their authenticity untrustworthy. CopyMove Forgery CMF is one of the most common forgeries present in an image where a cluster of pixels are duplicated in the same image with potential postprocessing techniques. Various state-of-art techniques are developed in the recent years which are effective in detecting passive image forgery. However most methods do fail when the copied image is rescaled or added with certain intensity before being pasted due to de-synchronization of pixels in the searching process. To tackle this problem the paper proposes distinct novel algorithms which recognize a unique approach of using Hus invariant moments and Discreet Cosine Transformations DCT to attain the desired rescale invariant and intensity invariant CMF detection techniques respectively. The experiments conducted quantitatively and qualitatively demonstrate the effectiveness of the algorithm., Comment: Further research is active on this paper in VIT University. Hence, the paper is yet not published
- Published
- 2018
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