Research Papers

# Overview of Frequentist and Bayesian approach to Survival Analysis

### Vinaitheerthan Renganathan

Applied Medical Informatics, 38(1), 25-38Abstract

Survival analysis is one of the main areas of focus in medical research in
recent years. Survival analysis involves the concept of 'Time to event'. The
event may be mortality, onset of disease, response to treatment etc. Purpose
of this paper is to provide overview of frequentist and Bayesian Approaches
to Survival Analysis. The paper starts with the overview of the basic
concepts of survival analysis and then discusses the frequentist and
Bayesian approaches to survival analysis in the biomedical domain with help
of hypothetical survival dataset. The survival analysis of the hypothetical
data sets showed that for the specific dataset and specific hypothesis,
Bayesian approach provided direct probability that the null hypothesis is
true or not and the probability that the unknown parameter (mean survival
time) lies in a given credible interval wherein the frequentist approach
provided p-values and confidence interval for interpreting whether the null
hypothesis is true or not and the percentage of intervals which will contain
the parameter when the experiment is repeated under same condition. The use
of Bayesian survival analysis in biomedical domain has increased due to the
availability of advanced commercial and free software, its ability to handle
design and analysis issues in survival model and the ease of interpretation
of the research findings.

Keyword :Biostatistics,surival,overview,frequentist,bayeisan,analysis,applied,medical,informatics,journal

**Citation: Renganathan, V. (2016). Overview of Frequentist and Bayesian Approach to Survival Analysis. Applied Medical Informatics, 38(1), 25.**

# Text Mining in Biomedical Domain with Emphasis on Document Clustering

### Vinaitheerthan Renganathan

Healthcare Informatics Research 2017 Jul; 23(03) 141-146Abstract

**Objectives:** With the exponential increase in the number of articles published every year in the biomedical domain,
there is a need to build automated systems to extract unknown information from the articles published.
Text mining techniques enablethe extraction of unknown knowledge from unstructured documents.

**Methods:** This paper reviews text mining processes in detail and the software tools available to carry out text mining.
It also reviews the roles and applications of text mining in the biomedical domain.

**Results**: Text mining processes, such as search and retrieval of documents, pre-processing of documents, natural language processing,
methods for text clustering, and methods for text classification are described
in detail.

**Conclusions:** Text mining techniques can facilitate the mining of vast amounts of knowledge on a
given topic from published biomedical research articles and draw meaningful conclusions that are not possible otherwise.

Keyword : Text Mining, Cluster Analysis, Classification, Natural Language Processing, Software

**Citation: Renganathan, V. (2017). Text Mining in Biomedical Domain with Emphasis on Document Clustering. Healthcare Informatics Research, 23(3), 141-146.**

# Tutorial on mining of biomedical literature with the help of R Package

**Vinaitheerthan Renganathan**

Abstract

Abstract

**Keywords**: Biomedical, Clustering, Classification, R
Software, Text mining

http://www.vinaitheerthan.com/TM.php

# Maximum Likelihood Estimation and Likelihood Ratio test revisited

Vinaitheerthan Renganahtan

**Abstract**

Maximum likelihood Estimation is an important aspect of frequentist approach which was introduced by RA Fisher [1]. Maximum Likelihood estimation method helps us to find the estimator for the unknown population parameter. There are other methods of estimation also available such as Least Square Estimation and Bayesian Estimation methods but Maximum Likelihood Estimation is the widely used method to estimate the parameters. This paper provides an overview of Maximum Likelihood Method with example to calculate a Maximum Likelihood Estimator from a sample data set.

**Keywords**: Maximum Likelihood, Frequentist

http://www.vinaitheerthan.com/MLE.php