Statistical physics of cascading failures in complex networks

Systems such as the power grid, world wide web (WWW), and internet are categorized as complex systems because of the presence of a large number of interacting elements. For example, the WWW is estimated to have a billion webpages and understanding the dynamics of such a large number of individual agents (whose individual interactions might not be fully known) is a challenging task. Complex network representations of these systems have proved to be of great utility. Statistical physics is the study of emergence of macroscopic properties of systems from the characteristics of the interactions between individual molecules. Hence, statistical physics of complex networks has been an effective approach to study these systems. In this dissertation, I have used statistical physics to study two distinct phenomena in complex systems: i) Cascading failures and ii) Shortest paths in complex networks. Understanding cascading failures is considered to be one of the “holy grails“ in the study of complex systems such as the power grid, transportation networks, and economic systems. Studying failures of these systems as percolation on complex networks has proved to be insightful. Previously, cascading failures have been studied extensively using two different models: k-core percolation and interdependent networks. The first part of this work combines the two models into a general model, solves it analytically, and validates the theoretical predictions through extensive computer simulations. The phase diagram of the percolation transition has been systematically studied as one varies the average local k-core threshold and the coupling between networks. The phase diagram of the combined processes is very rich and includes novel features that do not appear in the models which study each of the processes separately. For example, the phase diagram consists of first- and second-order transition regions separated by two tricritical lines that merge together and enclose a two-stage transition region. In the two-stage transition, the size of the giant component undergoes a first-order jump at a certain occupation probability followed by a continuous second-order transition at a smaller occupation probability. Furthermore, at certain fixed interdependencies, the percolation transition cycles from first-order to second-order to two-stage to first-order as the k-core threshold is increased. We setup the analytical equations describing the phase boundaries of the two-stage transition region and we derive the critical exponents for each type of transition. Understanding the shortest paths between individual elements in systems like communication networks and social media networks is important in the study of information cascades in these systems. Often, large heterogeneity can be present in the connections between nodes in these networks. Certain sets of nodes can be more highly connected among themselves than with the nodes from other sets. These sets of nodes are often referred to as ’communities’. The second part of this work studies the effect of the presence of communities on the distribution of shortest paths in a network using a modular Erdős-Rényi network model. In this model, the number of communities and the degree of modularity of the network can be tuned using the parameters of the model. We find that the model reaches a percolation threshold while tuning the degree of modularity of the network and the distribution of the shortest paths in the network can be used as an indicator of how the communities are connected

Design and investigation of sectoral circular disc monopole fractal antenna and its backscattering

AbstractThis article presents the design of sectoral circular disc fractal antenna. The proposed antenna has been excited using CPW – feed. The measured result of this antenna offers the ultra wideband characteristics from 3.265GHz to 15.0GHz. The measured and simulated results are compared and found in good agreement. The impedance match of the antenna throughout the band is improved by incorporating the rectangular slots in the ground plane. The measured radiation patterns of this antenna are nearly omni-directional in H-plane and bidirectional in E-plane. The backscattering of antenna is also discussed and calculated for antenna mode and structural mode scattering. This type of antenna is useful for UWB system, microwave imaging and vehicular radar, precision positioning location

A Deviant or a Victim of Pervasive Stigmatization: Wicked Women in Kavita Kané’s Lanka’s Princess

Building on the foundational theories of Judith Butler and Edwin Schur, this paper scrutinises the traditional myth of the Hindu epic the Ramayana and argues: (1) how socially constructed gender performance is naturalised by cultural ideology and (2) how infringement of this performance leads to labelling individuals as deviant. Women who transgress these cultural ideologies are defined as deviant and subjected to various punishments, from public humiliation to genital mutilation. Through an exploration of the novelist Kavita Kané’s mythology inspired novel Lanka’s Princess (2017), this paper focuses on the mythical figure known as Surpankha whose character embodies masculine attributes and vilified qualities that contradict the archetypal image of women in India, as prescribed by Hindu scriptures. This paper highlights the consequences of resistance and deviance when it comes to gender performance and examines mutilation from a feminist point of view. We also simultaneously remove Surpankha from her archetypal villainous image to the image of a ‘wronged’ woman. Hence, this study creates a lens for examining femininity, deviance, and ancient gender roles, particularly, when it comes to the performance of gender and the social construction of deviance. In doing so, this paper deconstructs the male-dominated structure of deviance and constructs a new understanding of the Ramayana