Search Results for author: Ranjan Maitra

Found 19 papers, 4 papers with code

Elliptically-Contoured Tensor-variate Distributions with Application to Improved Image Learning

no code implementations13 Nov 2022 Carlos Llosa-Vite, Ranjan Maitra

Statistical analysis of tensor-valued data has largely used the tensor-variate normal (TVN) distribution that may be inadequate when data comes from distributions with heavier or lighter tails.

Exploratory Factor Analysis of Data on a Sphere

no code implementations9 Nov 2021 Fan Dai, Karin S. Dorman, Somak Dutta, Ranjan Maitra

Data on high-dimensional spheres arise frequently in many disciplines either naturally or as a consequence of preliminary processing and can have intricate dependence structure that needs to be understood.

Fully Three-dimensional Radial Visualization

no code implementations19 Oct 2021 Yifan Zhu, Fan Dai, Ranjan Maitra

We develop methodology for three-dimensional (3D) radial visualization (RadViz) of multidimensional datasets.

Quantitative Matching of Forensic Evidence Fragments Utilizing 3D Microscopy Analysis of Fracture Surface Replicas

no code implementations24 Sep 2021 Bishoy Dawood, Carlos Llosa-Vite, Geoffrey Z. Thompson, Barbara K. Lograsso, Lauren K. Claytor, John Vanderkolk, William Meeker, Ranjan Maitra, Ashraf Bastawros

In this study, a statistical analysis comparison protocol was applied to a set of 3D topological images of fractured surface pairs and their replicas to provide confidence in the quantitative statistical comparison between fractured items and their replicas.

Fast model-based clustering of partial records

1 code implementation30 Mar 2021 Emily M. Goren, Ranjan Maitra

We compare our approximate algorithm to the corresponding full expectation-maximization (EM) approach that considers the missing values in the incomplete data set and makes a missing at random (MAR) assumption, as well as case deletion and imputation methods.

Clustering Imputation

A practical model-based segmentation approach for improved activation detection in single-subject functional Magnetic Resonance Imaging studies

1 code implementation6 Feb 2021 Wei-Chen Chen, Ranjan Maitra

Finally, the value of our suggested approach in low-signal and single-subject fMRI studies is illustrated on a sports imagination experiment that is often used to detect awareness and improve treatment in patients in persistent vegetative state (PVS).

Reduced-Rank Tensor-on-Tensor Regression and Tensor-variate Analysis of Variance

no code implementations18 Dec 2020 Carlos Llosa-Vite, Ranjan Maitra

Fitting regression models with many multivariate responses and covariates can be challenging, but such responses and covariates sometimes have tensor-variate structure.

regression

CatSIM: A Categorical Image Similarity Metric

no code implementations20 Apr 2020 Geoffrey Z. Thompson, Ranjan Maitra

We introduce CatSIM, a new similarity metric for binary and multinary two- and three-dimensional images and volumes.

Image Quality Assessment

Estimating Basis Functions in Massive Fields under the Spatial Mixed Effects Model

no code implementations12 Mar 2020 Karl T. Pazdernik, Ranjan Maitra

Spatial prediction is commonly achieved under the assumption of a Gaussian random field (GRF) by obtaining maximum likelihood estimates of parameters, and then using the kriging equations to arrive at predicted values.

Multi-layered characterization of hot stellar systems with confidence

no code implementations12 Mar 2020 Souradeep Chattopadhyay, Steven D. Kawaler, Ranjan Maitra

A nonparametric bootstrap procedure was also used to estimate the confidence of each of our group assignments.

Astronomy Clustering

A Matrix--free Likelihood Method for Exploratory Factor Analysis of High-dimensional Gaussian Data

no code implementations27 Jul 2019 Fan Dai, Somak Dutta, Ranjan Maitra

This paper proposes a novel profile likelihood method for estimating the covariance parameters in exploratory factor analysis of high-dimensional Gaussian datasets with fewer observations than number of variables.

Classification with the matrix-variate-$t$ distribution

no code implementations22 Jul 2019 Geoffrey Z. Thompson, Ranjan Maitra, William Q. Meeker, Ashraf Bastawros

Matrix-variate distributions can intuitively model the dependence structure of matrix-valued observations that arise in applications with multivariate time series, spatio-temporal or repeated measures.

Classification General Classification +2

TiK-means: $K$-means clustering for skewed groups

no code implementations21 Apr 2019 Nicholas S. Berry, Ranjan Maitra

The $K$-means algorithm is extended to allow for partitioning of skewed groups.

Clustering

Visualization of Labeled Mixed-featured Datasets

no code implementations6 Apr 2019 Yifan Zhu, Fan Dai, Ranjan Maitra

We develop methodology for visualization of labeled mixed-featured datasets.

Kernel-estimated Nonparametric Overlap-Based Syncytial Clustering

1 code implementation24 May 2018 Israel Almodóvar-Rivera, Ranjan Maitra

Here, we develop a distribution-free fully-automated syncytial clustering algorithm that can be used with $k$-means and other algorithms.

Clustering

An efficient $k$-means-type algorithm for clustering datasets with incomplete records

1 code implementation23 Feb 2018 Andrew Lithio, Ranjan Maitra

We also provide initialization strategies for our algorithm and methods to estimate the number of groups in the dataset.

Clustering Nonparametric Clustering

Merging $K$-means with hierarchical clustering for identifying general-shaped groups

no code implementations23 Dec 2017 Anna D. Peterson, Arka P. Ghosh, Ranjan Maitra

For instance, hierarchical clustering identifies groups in a tree-like structure but suffers from computational complexity in large datasets while $K$-means clustering is efficient but designed to identify homogeneous spherically-shaped clusters.

Clustering Density Estimation +1

Approximations in the homogeneous Ising model

no code implementations6 Dec 2017 Alejandro Murua-Sazo, Ranjan Maitra

The Ising model is important in statistical modeling and inference in many applications, however its normalizing constant, mean number of active vertices and mean spin interaction -- quantities needed in inference -- are computationally intractable.

Bayesian Inference

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