Browsing by Author "Kamath, S.S."
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Item Algorithmic aspects of k-part degree restricted domination in graphs(World Scientific wspc@wspc.com.sg, 2020) Kamath, S.S.; Senthil Thilak, A.; Rashmi, M.The concept of network is predominantly used in several applications of computer communication networks. It is also a fact that the dominating set acts as a virtual backbone in a communication network. These networks are vulnerable to breakdown due to various causes, including traffic congestion. In such an environment, it is necessary to regulate the traffic so that these vulnerabilities could be reasonably controlled. Motivated by this, k-part degree restricted domination is defined as follows. For a positive integer k, a dominating set D of a graph G is said to be a k-part degree restricted dominating set (k-DRD set) if for all u ? D, there exists a set Cu ? N(u) ?(V ? D) such that |Cu| ? ?d(ku) ? and Su?D Cu = V ? D. The minimum cardinality of a k-DRD set of a graph G is called the k-part degree restricted domination number of G and is denoted by ? dk (G). In this paper, we present a polynomial time reduction that proves the NP-completeness of the k-part degree restricted domination problem for bipartite graphs, chordal graphs, undirected path graphs, chordal bipartite graphs, circle graphs, planar graphs and split graphs. We propose a polynomial time algorithm to compute a minimum k-DRD set of a tree and minimal k-DRD set of a graph. © 2020 World Scientific Publishing Co. Pte Ltd. All rights reserved.Item An improved bound on weak independence number of a graph(2013) Bhat, R.S.; Kamath, S.S.; SurekhaA vertex v in a graph G=(V,X) is said to be weak if d(v)≤d(u) for every u adjacent to v in G. A set S ⊆ V is said to be weak if every vertex in S is a weak vertex in G. A weak set which is independent is called a weak independent set (WIS). The weak independence number wβ0(G) is the maximum cardinality of a WIS. We proved that wβ0(G)≤ p-δ. This bound is further refined in this paper and we characterize the graphs for which the new bound is attained.Item Analysis of Kapferer Mine Network using Graph Energy Ranking(Institute of Electrical and Electronics Engineers Inc., 2019) Mahadevi, S.; Kamath, S.S.Vertex centrality is one of the procedures to evaluate complex networks, and it can disclose current patterns of networks. By evaluating their structural characteristics, it enables us to understand networks and their elements. One of the complex networks of nodes and interactions is the social network. It is increasing very greatly every day owing to the addition of fresh nodes. In such a vast network, therefore, not all nodes are equally essential, identifying influential nodes becomes a practical issue. To quantify the significance of nodes in networks, centrality measures were implemented. The multiple criteria are used to select critical nodes in the network. Various centrality measures such as Betweenness Centrality, Degree Centrality, Closeness Centrality, and some well-known centrality measures are therefore used to define vital nodes. In this article, we suggested a centrality to rank the nodes using a graph invariant called graph energy named as Graph-Energy-Ranking (GER). GER provides a better knowledge of the current network by evaluating the effect of node deletion on graph connectivity and thus enables us to better understand and maintain the network. In the current paper GER is applied on well-known social network called Kapferer mine network and results have been discussed. © 2019 IEEE.Item Analyzing data incompleteness for MRI Data for quality enhancement(Institute of Electrical and Electronics Engineers Inc., 2024) Shanbhag, S.; Raju, S.; Gurupur, V.P.; Kamath, S.S.; Kandala, R.N.V.P.S.; Trader, A.E.; Lal, S.Magnetic resonance imaging (MRI) is a powerful medical imaging technique widely used for diagnosing various conditions because it provides detailed images of internal structures within the body. However, like any imaging modality, MRI images can be susceptible to artifacts that may arise from various sources, including hardware imperfections, patient motion, and image acquisition techniques. Detecting and mitigating these artifacts are crucial steps in ensuring MRI scans' reliability and clinical utility. In this paper, we present algorithms specifically designed to address the challenges of undersampling and motion artifacts in MR images. Our approach involves leveraging advanced image processing techniques, including line detection algorithms for undersampling detection and blur parameter estimation for motion artifact analysis. By accurately identifying and quantifying these artifacts, our algorithms aim to improve MRI data's overall quality and completeness, ultimately enhancing diagnostic accuracy and patient care. © 2024 The Authors.Item Bounds on k-part degree restricted domination number of a graph(Tsing Hua University, 2021) Kamath, S.S.; Senthil Thilak, A.; Maladi, R.For a positive integer k, a dominating set D of a graph G is said to be a k-part degree reslrictedm dominating set (k-DRD set) if for all u 2 D, there exists a set [Formula Presented] The minimum cardinality of a k-DRD set of a graph G is called the k-part degree restricted domination number of G and is denoted by ?d/k (G). In this paper, we provide some bounds on ?d/k of join of two graphs, bounds on ?d/k in terms of maximum degree, independence number and covering number. Further, we discuss some Nordhaus-Gaddum type results. In addition to this, we prove that for any graph G, ?d/k (G)??k (G), where ?k (G) is the k-domination number of G and we characterize the trees T for which ?d/k(?)= ?k(G). © 2021, Tsing Hua University. All rights reserved.Item Changing and unchanging efficient domination in graphs with respect to edge addition(Cambridge Scientific Publishers boch@lnfm1.sai.msu.ru, 2020) Senthil Thilak, A.S.; Shet, S.V.; Kamath, S.S.A dominating set S of a graph g is an efficient dominating set (EDS) of g if Ng[v]?S=1, for all v e V(g). g is efficiently dominatable or efficient if it has an EDS. Not all graphs are efficient. The class of efficient graphs is denoted by E. If g e E, then any EDS of g has its cardinality equal to the domination number of g, denoted by g(g). An edg+e e e E(g) is critical or g-critical if y(g+e) ? y(g). The study of critical concepts exists for domination and its variants. We extend this study to graphs which are efficient. This paper deals with the study of the properties of critical edg+es of graphs in E. Depending on whether the addition of an edg+e increases or decreases or leaves unaltered g(g), the edg+e set of g is classified respectively into three sets: EA+, EA-, EA0. To study the changing and unchanging property of efficient domination, we define the classes UEAE = UEA? g+e, CEAE = CEA?g+e, where g+e = {g: g ? E and g+e ? E, for all e ? E(g)g, UEA = (g: g(g) = g(g+e), for all e ? E(g)g and CEA = (g: g(g) ? g(g+e), for all e ? E(g)g. We characterize the critical edg+es, edg+e critical sets, the two classes of graphs defined above and identify their relationship with critical vertices of those graphs in E. We also identify the relationship between all classes of graphs resulting from vertex criticality (vertex removal) and edg+e criticality (edg+e removal and edg+e addition) and represent through Venn diagram. This study plays a significant role in the analysis and design of fault tolerant networks. © 2020 by the authors.Item Domination Critical Semigraphs(2003) Kamath, S.S.; Hebbar, S.R.Sampathkumar [1] introduced a new type of generalization to graphs, called Semigraphs. A semigraph G = (V, X) on the set of vertices V and the set of edges X consists of n-tuples (u1,u2,un) of distinct elements belonging to the set V for various n ? 2, with the following conditions : (1) Any n-tuple (u1,u2,un) = (un,un-1,...,u1) and (2) Any two such tuples have at most one element in common. S. S. Kamath and R. S. Bhat [3] introduced domination in semigraphs. Two vertices u and v are said to a-dominate each other if they are adjacent. A set D ? V(G) is an adjacent dominating set (ad-set) if every vertex in V - D is adjacent to a vertex in D. The minimum cardinality of an ad-set D is called adjacency domination number of G and is denoted by ?a.. ?a(G) may increase or decrease by the removal of a vertex or an edge from G. A vertex v of a semigraph G is said to be ?a - critical if ?a(G - v) ? ?a(G); if ?a(G - v) = ?a(G), then v is ?a - redundatnt. The main objective of this paper is to study this phenomenon on the vertices and edges of a semigraph. 2005 Elsevier Ltd. All rights reserved.Item Enhancing QoS in a University Network by using Containerized Generic Cache(Institute of Electrical and Electronics Engineers Inc., 2020) Praveen Raj, H.L.; Tahiliani, M.P.; Mohanan, P.G.; Kamath, S.S.Ubiquitous access and enhanced Internet speeds have paved ways for online educational reforms at a large scale. There has been a widespread adoption of modern educational applications, ranging from interactive applets, video lessons and online quizzes to remotely conducting laboratory experiments. Consequently, there is a demand to provision more bandwidth to satisfy the users expectations. In this paper, we propose an approach to enhance the Quality of Service (QoS) in a University campus network and efficiently utilize the available bandwidth. Typically within a University, some requests are similar e.g., operating system updates, Linux package installs, Python pip packages and others. These are huge data transfer requests ranging from Megabytes to Gigabytes, and consume a large amount of bandwidth on external access links to the Internet. Redundant requests of this nature from a large user base lead to enormous wastage of bandwidth. The proposed approach overcomes this concern by setting up a containerized forward proxy with a generic cache for popular traffic in the University. Our experiments on a live network at National Institute of Technology Karnataka, Surathkal show that a large number of redundant requests can be successfully served from this Virtualized Network Function (VNF), thereby enhancing the QoS and efficiently utilizing the available bandwidth. The proposed system is able to reduce the latency by over 60% and saves 34GB of data per day on an average. Although the proposed approach is tested in a University environment in this work, it is applicable for other caching requirements with minor modifications. Moreover, since this cache is implemented as a VNF, it is portable and easy to deploy. © 2020 IEEE.Item ES-HAS: ECC-based secure handover authentication scheme for roaming mobile user in global mobility networks(MDPI, 2021) Suvidha, K.S.; Ramalingam, J.; Kamath, S.S.; Lee, C.-C.The design and implementation of two-factor schemes designed for roaming mobile users for global mobility networks in smart cities requires attention to protect the scheme from various security attacks, such as the replay attack, impersonation attack, man-in-the-middle attack, password-guessing attack and stolen-smart-card attack. In addition to these attacks, the scheme should achieve user anonymity, unlinkability and perfect forward secrecy. In the roaming scenario, as mobile users are connected to the foreign network, mobile users must provide authentication details to the foreign network to which they are connected. The foreign network forwards the authentication messages received from the mobile users to their home network. The home network validates the authenticity of the mobile user. In the roaming scenario, all communication between the three entities is carried over an insecure channel. It is assumed that the adversary has the capabilities to intercept the messages transmitted over an insecure channel. Hence, the authentication scheme designed must be able to resist the above-mentioned security attacks and achieve the security goals. Our proposed scheme ES-HAS (elliptic curve-based secure handover authentication scheme) is a two-factor authentication scheme in which the mobile user possesses the password, and the smart card resists the above-mentioned security attacks. It also achieves the above-mentioned security goals. We also extended our two-factor authentication to a multi-factor authentication scheme using the fingerprint biometric technique. The formal security analysis using BAN logic and the formal security verification of the proposed scheme using the widely accepted AVISPA (automated validation of internet security protocols and applications) tool is presented in this article. In comparison with the related schemes, the proposed scheme is more efficient and robust. This makes the proposed scheme suitable for practical implementation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Item Generating Clinically Relevant Radiology Reports using Multimodal Deep Learning Models(Association for Computing Machinery, Inc, 2025) Mahajan, R.; Kamath, S.S.Generating radiology reports is an important component of the diagnostic process, facilitating the interpretation of medical images and subsequent clinical decision making. Recent advancements have opened new pathways to automate the generation of radiology reports, a task traditionally performed by radiologists through meticulous analysis of medical images. This study presents a framework that uses deep learning and NLP to automate the generation of radiology reports from chest X-ray images. Our approach utilizes a pre-trained RAD-DINO model to extract features from radio-graphic images and an encoder-decoder model to create coherent textual descriptions. The proposed models produced coherent reports outperforming several existing state-of-the-art methods when evaluated using standard metrics like BLEU. © 2024 Copyright held by the owner/author(s).Item Graph Energy Based Centrality Measure to Identify Influential Nodes in Social Networks(Institute of Electrical and Electronics Engineers Inc., 2019) Kamath, S.S.; Mahadevi, S.One of the measures to analyze complex network is vertex centrality; it can reveal existing network patterns. It helps us in understanding networks. One of the measures to analyze complex network is vertex centrality, and it can reveal existing network patterns. It helps us in understanding networks and their components by analyzing their structural properties. The social network is one of the complex networks which is composed of nodes and relationships. It is growing very vastly due to the addition of new nodes every day. All nodes are not equally important in such a vast network hence, identifying influential nodes becomes a practical problem. Centrality measures were introduced to quantify the importance of nodes in networks. The various criterion is used to select critical nodes in the network. Therefore, different centrality measures like Betweenness Centrality, Degree Centrality, Closeness Centrality, and other well-known centrality measures are used to identify essential nodes. We have proposed an algorithm to compute a centrality using graph energy called Energy-Based-Centrality-Measure (EBCM) in this paper. It identifies the central nodes based on a graph invariant called graph energy. EBCM gives a better understanding of the current network by analyzing the impact of node deletion on graph connectivity and thereby helps us in achieving a better network understanding ability and maintenance. © 2019 IEEE.Item Graph energy centrality: a new centrality measurement based on graph energy to analyse social networks(Inderscience Publishers, 2022) Mahadevi, S.; Kamath, S.S.; Shetty D, P.D.Critical node identification, one of the key issues in social network analysis, is addressed in this article with the development of a new centrality metric termed graph energy centrality (GEC). The fundamental idea underlying this GEC measure is to give each vertex a centrality value based on the graph energy that results from vertex elimination. We show that the GEC of each vertex is asymptotically equal to two for cycle graphs and exactly equal to two for complete graphs. We further demonstrate that star graphs can be ranked using only two GEC values, whereas path graphs can be ranked using a maximum of ⌈n+12 ⌉ values. The proposed algorithm takes O(n3) time complexity to rank all vertices; hence an optimised algorithm is also being proposed considering only a few classes of graphs. The proposed algorithm ranks the nodes based on the collaborative measure of eigenvalues. © 2022 Inderscience Enterprises Ltd.. All rights reserved.Item Graph energy ranking for scale-free networks using Barabasi-Albert model(Institute of Electrical and Electronics Engineers Inc., 2019) Mahadevi, S.; Kamath, S.S.A social network is a vast collection of actors and interactions. It forms one of the complex networks. There are various types of social networks such as acquaintance networks, online social networks, covert networks, citation networks, and collaboration networks, etc. Most of these real-world networks are scale-free, and they follow a power-law distribution. Each of these networks has nodes which have various roles to play, and all nodes are not equally important. Hence we need to rank them based on their importance. In this paper, we propose an algorithm named Graph Energy Ranking (GER) to rank the nodes of scale-free networks built using the Barabasi-Albert model. GER analyses the impact of node deletion on the underlying network and therefore gives a better understanding of the network features. Study of ranking done by existing centrality measures versus GER is performed to observe the similarity in the ranking process. ©2019 IEEE.Item Imbalanced Multi-Class Research Article Classification using Sentence Transformers and Machine Learning Algorithms(Association for Computing Machinery, Inc, 2025) Gowhar, S.; Kempaiah, P.; Kamath, S.S.; Sugumaran, V.Categorizing scientific articles into specific research fields is a challenging problem, considering the volume and variety of published literature. However, existing classification systems often suffer from limitations regarding taxonomy or the models used for classification. This article explores approaches built on Sentence Transformer embeddings combined with Machine Learning algorithms to classify articles into 123 predefined classes, with the dataset being heavily imbalanced in nature. The effectiveness of Large Language Models (LLMs) for generating synthetic data is also experimented with, along with synonym augmentation and SMOTE. The best-performing model, the One vs Rest classifier trained on MP-Net sentence embeddings with SMOTE, achieved an accuracy of 77%, and outperformed all the other models. © 2024 Copyright held by the owner/author(s).Item Neighborhood contraction in graphs(Indian National Science Academy insa@giasdl01.vsnl.net.in, 2016) Kamath, S.S.; Kolake, P.Let G be a graph and v be any vertex of G. Then the neighborhood contracted graphGv of G, with respect to the vertex v, is the graph with vertex set V ? N(v), where two vertices u,w ? V ? N(v) are adjacent in Gv if either w = v and u is adjacent to any vertex of N(v) in G or u,w ? N[v] and u,w are adjacent in G. The properties of the neighborhood contracted graphs are discussed in this paper. The neighborhood contraction in some special class of graphs, the domination in a graph and the neighborhood contracted graphs are discussed in the paper. © 2015, The Indian National Science Academy.Item On strong (weak) independent sets and vertex coverings of a graph(2007) Kamath, S.S.; Bhat, R.S.A vertex v in a graph G = (V, E) is strong (weak) if deg (v) ? deg (u)(deg (v) ? deg (u)) for every u adjacent to v in G. A set S ? V is said to be strong (weak) if every vertex in S is a strong (weak) vertex in G. A strong (weak) set which is independent is called a strong independent set [SIS] (weak independent set [WIS]). The strong (weak) independence numbers ? = s ? (G) (w ? = w ? (G)) is the maximum cardinality of an SIS (WIS). For an edge x = uv, v strongly covers the edge x if deg (v) ? deg (u) in G. Then u weakly covers x. A set S ? V is a strong vertex cover [SVC] (weak vertex cover [WVC]) if every edge in G is strongly (weakly) covered by some vertex in S. The strong (weak) vertex covering numbers ? = s ? (G)(w ? = w ? (G)) is the minimum cardinality of an SVC (WVC). In this paper, we investigate some relationships among these four new parameters. For any graph G without isolated vertices, we show that the following inequality chains hold: s ? ? ? ? s ? ? w ? and s ? ? w ? ? ? ? w ?. Analogous to Gallai's theorem, we prove s ? + w ? = p and w ? + s ? = p. Further, we show that s ? ? p - ? and w ? ? p - ? and find a necessary and sufficient condition to attain the upper bound, characterizing the graphs which attain these bounds. Several Nordhaus-Gaddum-type results and a Vizing-type result are also established. © 2006.Item Performance analysis of a cooperative MAC protocol of wireless ad hoc networks(Medknow Publications B9, Kanara Business Centre, off Link Road, Ghatkopar (E) Mumbai 400 075, 2014) Chavhan, S.; Venkataram, P.; Chetan Kumar, S.; Kamath, S.S.Different medium access control (MAC) layer protocols, for example, IEEE 802.11 series and others are used in wireless local area networks. They have limitation in handling bulk data transfer applications, like video-on-demand, videoconference, etc. To avoid this problem a cooperative MAC protocol environment has been introduced, which enables the MAC protocol of a node to use its nearby nodes MAC protocol as and when required. We have found on various occasions that specified cooperative MAC establishes cooperative transmissions to send the specified data to the destination. In this paper we propose cooperative MAC priority (CoopMACPri) protocol which exploits the advantages of priority value given by the upper layers for selection of different paths to nodes running heterogeneous applications in a wireless ad hoc network environment. The CoopMACPri protocol improves the system throughput and minimizes energy consumption. Using a Markov chain model, we developed a model to analyse the performance of CoopMACPri protocol; and also derived closed-form expression of saturated system throughput and energy consumption. Performance evaluations validate the accuracy of the theoretical analysis, and also show that the performance of CoopMACPri protocol varies with the number of nodes. We observed that the simulation results and analysis reflects the effectiveness of the proposed protocol as per the specifications. Copyright © 2014 by the IETE.Item Relation between k-DRD and dominating set(Springer International Publishing, 2019) Kamath, S.S.; Senthil Thilak, A.; M, R.In this paper, a new parameter on domination is defined by imposing a restriction on the degrees of vertices in the dominating set. For a positive integer k, a dominating set D of a graph G is said to be a k-part degree restricted dominating set (k-DRD-set), if for all u ∈ D there exists a set C u ⊆ N(u) ∩ (V − D) such that |Cu|≤⌈d(u)k⌉ and ⋃ u ∈ D C u = V − D. The minimum cardinality of a k-part degree restricted dominating set of G is called the k-part degree restricted domination number of G and is denoted by γdk(G). Here, we determine the k-part degree restricted domination number of some well-known graphs, relation between dominating and k-DRD set, and an algorithm which verifies whether a given dominating set is a k-DRD set or not. © Springer Nature Switzerland AG 2019.