Indian Institute of Technology, Jodhpur

About: Indian Institute of Technology, Jodhpur is a education organization based out in Jodhpur, India. It is known for research contribution in the topics: Computer science & Welding. The organization has 914 authors who have published 2221 publications receiving 19243 citations.

Maximum Weighted Edge Biclique Problem on Bipartite Graphs

Abstract: For a graph G, a complete bipartite subgraph of G is called a biclique of G. For a weighted graph \(G=(V,E,w)\), where each edge \(e\in E\) has a weight \(w(e)\in \mathbb {R}\), the Maximum Weighted Edge Biclique (MWEB) problem is to find a biclique H of G such that \(\sum _{e\in E(H)}w(e)\) is maximum. The decision version of the MWEB problem is known to be NP-complete for bipartite graphs. In this paper, we show that the decision version of the MWEB problem remains NP-complete even if the input graph is a complete bipartite graph. On the positive side, if the weight of each edge is a positive real number in the input graph G, then we show that the MWEB problem is \(O(n^2)\)-time solvable for bipartite permutation graphs, and \(O(m+n)\)-time solvable for chain graphs, which is a subclass of bipartite permutation graphs.

Solution Processed Hafnia Nanoaggregates: Influence of Surface Oxygen on Catalytic Soot Oxidation

Abstract: Hafnium dioxide (HfO2) nanoaggregates are synthesized by sol–gel and hydrothermal routes followed by hydrogen annealing at different time durations. The proposed study aims to explore the effect of hydrogen annealing time on the properties of HfO2 and also envisage the catalytic soot oxidation using HfO2 nanoaggregates. It is observed that annealing under a hydrogen atmosphere brought about substantial changes in certain attributes such as chemical and textural properties with marginal changes in some other properties like optical activity and band gap. The pristine HfO2 without hydrogen annealing showed a lower ignition temperature, whereas hydrogen annealed HfO2 for 2 h showed the best catalytic performance characterized by the soot combustion temperature (T50) in contrast to samples prepared at longer duration because of the higher surface adsorbed oxygen species in its widely distributed pores.

Laplacian matrices of weighted digraphs represented as quantum states

Abstract: Representing graphs as quantum states is becoming an increasingly important approach to study entanglement of mixed states, alternate to the standard linear algebraic density matrix-based approach of study. In this paper, we propose a general weighted directed graph framework for investigating properties of a large class of quantum states which are defined by three types of Laplacian matrices associated with such graphs. We generalize the standard framework of defining density matrices from simple connected graphs to density matrices using both combinatorial and signless Laplacian matrices associated with weighted directed graphs with complex edge weights and with/without self-loops. We also introduce a new notion of Laplacian matrix, which we call signed Laplacian matrix associated with such graphs. We produce necessary and/or sufficient conditions for such graphs to correspond to pure and mixed quantum states. Using these criteria, we finally determine the graphs whose corresponding density matrices represent entangled pure states which are well known and important for quantum computation applications. We observe that all these entangled pure states share a common combinatorial structure.

Recognition of power quality disturbances using S-transform and rule-based decision tree

Abstract: This paper presents a method for recognition of power quality disturbances using Stockwell's transform. Power quality disturbances are generated using MATLAB as per IEEE standards. Various features of signals are extracted from the multi-resolution analysis based on Stockwell's transform. These features are used to classify various power quality disturbances using the rule-based decision tree. It is observed that high efficiency of classification is achieved using S-transform based ruled decision tree. The investigated power quality disturbances include voltage sag, swell, interruption, harmonics, notch, flicker, oscillatory transient, impulsive transient and spike. Effectiveness of the proposed algorithm has been established by satisfactory results of various case studies.