Kostas Maistrelis

Population Dynamics — From the Derivative to the Logistic Equation

Kostas Maistrelis — Wed, 01 Jul 2026 21:34:52 +0300

A series of (R Markdown) lessons built step by step: first the concept of the derivative as a rate of change, then exponential population growth via a differential equation, and finally the logistic equation when space and resources impose limits. Best read in order.

Introduction to Derivatives — A Car on the Road

Kostas Maistrelis — Tue, 30 Jun 2026 18:07:48 +0300

A short introduction/reminder to the concept of the derivative — the «rate of change». Each lesson opens as a standalone page (R Markdown).

2nd official meetup of the Greece PostgreSQL Users Group

Kostas Maistrelis — Mon, 22 Jun 2026 00:13:16 +0300

On 5 June 2026 the second meetup of the Greece PostgreSQL User Group took place.

I had the pleasure of taking part as a speaker, presenting "PostgreSQL & Tree Structures".

You can view the presentation here: PostgreSQL & Tree Structures

The Normal Distribution and its origin

Kostas Maistrelis — Mon, 23 Feb 2015 21:32:16 +0200

Quite a few statistics and probability textbooks with an introduction to the normal distribution have passed through my hands. They almost always started with the mathematical definition and moved on to the properties and uses of the distribution. For a long time I had not found a book that explained how this formula came about — until at some point a book called Lady Luck fell into my hands which, although old, is a very good introduction to the subject of probability, and in it I found the first clear description of how the normal distribution arises.