@sepdek's

Analysis of (time-series) data being collected in (near) realtime often provides insight for a process underway. As the current situation with COVID-19 is still critical lots of data are being collected, curated and streamed throughout the world, and researchers strive to get the most out of them to identify patterns and, maybe, make predictions. In […]

I was recently editing the second edition of my book on 3D digitisation using LaTeX and stumbled on an unexpected obstacle. The book consists of a number of chapters thus it is more convenient to edit them separately. In addition, I wanted to have bibliography at the end of each chapter, so that each chapter […]

The official Dropbox client application, at least to date, supports one and only one user account per personal computer user. This means that if a user has multiple accounts there is no official way to synchronise all Dropbox accounts under one personal computing device user account. Nevertheless, it is fairly easy and simple to activate […]

Clustering is an important category of machine learning methods and a main form of unsupervised learning. Clustering is essentially distinctive and substantially different from the other dominant form of machine learning, classification, in that it does not rely on training (supervised learning). In principle, clustering represents any method that tries to identify and distinguish groups […]

Of the most basic forms of a machine learning system based on neural networks is the one in which training is accomplished using back error propagation, or simply back-propagation. Back-propagation is a technique, like many others, that targets the minimisation of a cost function during a learning process by following the descending gradient of the […]

Machine learning is a research domain that is becoming the holy grail of data science towards the modelling and solution of science and engineering problems. I have already witnessed researchers proposing solutions to problems out of their area of expertise using machine learning methods, basing their approach on the success of modern machine learning algorithm […]

This post serves as a practical approach towards a vectorized implementation of the Expectation Maximization (EM) algorithm mainly for MATLAB or OCTAVE applications. EM is a really powerful and elegant method for finding maximum likelihood solutions in cases where the hypothesis involves a gaussian mixture model and latent variables. Introduction EM is connected with the […]

There is often a need to use a webpage as a reference. So how is it possible to get the most recent date that webpage was updated? There have been people suggesting that one might exploit the power of google and execute a specific kind of search that might reveal the date of a webpage. […]

Everyone loves automation. Automation is conservation of energy; its like the habits we people are into, the habits that seem to be there for all living entities. One great automation option we may enjoy in our everyday work is that provided by the operating systems on our computers to perform tasks for us. One such […]

The following set of shell commands are among the basic steps to setup a Linux-based web server (LAMP=Linux Apache MySQL PHP). The procedure has been tested on an Ubuntu 14.04.05 Trusty Tahr (LTS) installation. Most steps and procedures are based on the tutorial found in DigitalOcean and in the linked pages. In the commands that […]

This post serves as a cheat sheet for differentiation. It just includes the most basic of the rules to be remembered when computing derivatives. First a little reminder on the notation being used in differentiation. Leibniz’s notation for the first derivative of a function f(x) is Newton’s notation for the first derivative of a function […]

There is a really large number of applications in engineering, in which the identification of critical points of a function is crucial for the analysis and modeling of a process or a system. Generally, one may identify three kinds of critical points, that is (a) maxima, (b) minima and (c) saddle or stationary inflection points. […]