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Full-Text Articles in Physical Sciences and Mathematics
Scaling Limits Of Some Random Interface Models., Biltu Dan Dr.
Scaling Limits Of Some Random Interface Models., Biltu Dan Dr.
Doctoral Theses
In this thesis, we study some probabilistic models of random interfaces. Interfaces between different phases have been topic of considerable interest in statistical physics. These interfaces are described by a family of random variables, indexed by the ddimensional integer lattice, which are considered as a height configuration, namely they indicate the height of the interface above a reference hyperplane. The models are defined in terms of an energy function (Hamiltonian), which defines a Gibbs measure on the set of height configurations. More formally, letÏ• = {Ï•x}x∈Z dbe a collection of real numbers indexed by the d-dimensional integer lattice Z d. …
Contributions To Random Energy Models., Nabin Kumar Jana Dr.
Contributions To Random Energy Models., Nabin Kumar Jana Dr.
Doctoral Theses
In this introductory chapter, we begin with a brief description of spin glasses in section 1. We are not physicists. The purpose of this section is to trace the history of the models. Section 2 gives a brief summary of the thesis and section 3 recalls certain known facts which will be used later in the thesis.Origin of the problem The models considered in this thesis have their origin in spin glass theory. Roughly, spin glass is a glassy state in a spin system or a disordered material exhibiting high magnetic frustration. The origin of this behavior can be either …
Boolean Functions With Important Cryptographic Properties., Subhamoy Maitra Dr.
Boolean Functions With Important Cryptographic Properties., Subhamoy Maitra Dr.
Doctoral Theses
In this thesis we concentrate on properties of cryptographically significant Boolean functions.The techniques are mainly combinstorial and provide new resulta on enumeration and construction of such functions. Initially we concentrate on a partieular subset of Boolean functions called the symmetric Boolean functions. A closed form expression for the Walsh transform of an arbitrary symmetric Boolean function is presented. We completely characterize the symmetric functions with maximum nonlinearity and show that the maximum nonlinearity of n-variable symmetrie function can be 2n-1-2[n-1l2], Moreover, new classes of symmetric balanced and symmetric correlation immune functions are considered.We provide a randomised heuristic to construct balanced …
Quantum Stochastic Dilation Of Completely Positive Semigroups And Flows., Debashish Goswami Dr.
Quantum Stochastic Dilation Of Completely Positive Semigroups And Flows., Debashish Goswami Dr.
Doctoral Theses
The central theme of the present thesia is quantum stochastic dilation af semigroupe of completely panitive mapa on operator algebran. It is the sim of all mathemati- cal, or even all scientific theorics, to understand a given class of objects through a tanonical and simpler subclass of it. For example, abstract C"-algebras are studied through their conerete realisation as elgebra of operators, contractions on a Hilbert space by unitaries. Hilbert modules by the factorissble ones, to mention anly a few. In most af these caes, a general object of the relavant class is sociated with a canonical candidate of the …
Neuro Fuzzy Reasoning For Pattern Classification And Object Recognition., Jayati Ghosh Dr.
Neuro Fuzzy Reasoning For Pattern Classification And Object Recognition., Jayati Ghosh Dr.
Doctoral Theses
In real world, pattern classification and object recognition problems are faced with fuzzi- ness that is connected with diverse facets of cognitive activity of the human being. An origin of sources of fuzziness is related to labels expressed in feature space as well as to labels of classes taken into account in classification and /or recognition procedures. Though a lot of scientific efforts have already been dedicated to pattern recognition problems, especially to classification procedures, still pattern recognition is confronted with a continuous challenge coming from a human being who can perform lot of ex- tremely complex classification tasks by …
Discrete Singularity Method And Its Application To Incompressible Flows., S K. Venkatesan Dr.
Discrete Singularity Method And Its Application To Incompressible Flows., S K. Venkatesan Dr.
Doctoral Theses
The smooth flow of a fluid has sprung many surprises. A flow which at an instant of time is quite regular and orderly could produce on the slightest of disturbance a complex bewildering varieties of flows, broadly termed as turbulence. Direct numerical simulation of the Navier-Stokes equations have shown that it is quite possible that these turbulent flows are solutions of the Navier-Stokes equations. In fact it is by now well recognized that many non-linear systems produce chaos quite similar to turbulence. However the large number of scales and their complex interactions involved make turbulence difficult to understand. Direct numerical …