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Dirichlet Process Mixture Models

Introduction to Mixtures Models Data is often a heterogeneous mix of different types of groups. In such scenarios, we need variable(s) to identify the group or category to which the data point belongs. Finite mixture models are a popular choice to model data with known/unknown group structures. If the group structure is known, we have a classifi...

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SECT statistic

Introduction to Persistence Diagrams The objective of this blog post is to summarize my understanding of the theory and applications behind Smooth Euler Characteristic Transform (SECT) statistic which was first introduced by Crawford et al1 in 2020. The SECT statistic summarizes the shape information associated with an object as a collection of ...

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Git Bash

The blog’s primary objective is to provide a big picture of what Git Bash is, its importance, and how it is used on a Windows Operating System. Software Carpentry’s course “The Unix Shell”1 is the primary reference for the blog. The necessary download instructions are given in this link under the title “The Bash Shell”. Following these instructi...

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Neurovascular coupling

Introduction Neurovascular coupling is one of the important principles on which fMRI image acquisition relies. Neurovascular coupling describes the relationship between neuronal activity and associated changes in blood flow. Angelo Mosso (1846–1910) was an early scientist trying to quantify human brain neuronal activity 1. He was the first to p...

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Mapper Algorithm

The objective of this blog is to document my understanding of the Mapper algorithm1 introduced by Singh et al. along with a review of available statistical literature on the Mapper. The textbook by Prof. Tamal Dey2 is an extremely helpful source for understanding the topological motivation behind Mapper. In particular, chapters 7 and 9 of the te...

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Discrete Morse Theory - II

The current post is a continuation of an earlier post Discrete Morse Theory - I. While part one focused mostly on topological concepts, the second part focuses on combinatorial interpretations and constructions associated with a simplicial complex. The primary reference is Chapter 10 of the textbook “Organized Collapse: An Introduction to Discre...

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Abstract and Geometric Simplicial Complexes

Abstract and Geometric Simplicial complexes An abstract simplicial complex $\mathcal{X}$ is a collection of finite sets that are closed under taking subsets. Note that, the empty set $\emptyset$ is assumed to lie in $\mathcal{X}$. Although each element of the abstract simplicial complex must be a finite set, the cardinality of the complex in its...

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Discrete Morse Theory - I

The blog introduces terms and results from Discrete Morse Theory that will eventually be helpful in understanding the paper The Morse Theory of Cech and Delaunay Complexes by U. Bauer and H. Edelsbrunner1. The textbook I adhered to learn the basics is the textbook “Organized Collapse: An Introduction to Discrete Morse Theory” by Dmitry N. Kozlov...

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