I have been neglecting my blog lately as some major changes happened in my life. About three weeks ago I said goodbye to academia and started working at RELEX Solutions, a growing Finnish (& international) software company which offers automatized solutions for managing the supply chain processes. Leaving academia - after about 10 years, studying […]
Category: experimental math
A small guide to Random Forest - part 2
This is the second part of a simple and brief guide to the Random Forest algorithm and its implementation in R. If you missed Part I, you can find it here. randomForest in R R has a package called randomForest which contains a randomForest function. If you want to explore in depth this implementation, I […]
A small guide to Random Forest - part 1
I've recently started playing with Kaggle and got curious about one of the most famous classification/regression framework, Random Forest. In a problem of classification or regression, several random decision trees (a "forest") are built and at the end the outputs are combined ("bagging"). The intuition is that randomness and a meaningful quantity of trees will avoid […]
Open Data: CT datasets and prototypes
In my research work, I often find it difficult to get datasets for X-ray CT for method validation, neither simulated and real data. Of course, there's the classic Shepp-Logan phantom, but in many cases it would save a lot of work to download datasets to test one's methods. As for my knowledge, there is no broad […]
Live from Inverse Days 2015: baby on board
This week I did something a little crazy, dictated by necessity: I took my 2 year old girl to a conference, namely the Inverse Days in Lappeenranta. We drove from Espoo (bad idea) on Monday evening and will stay until Thursday, cutting at half day to get home not too late. Baby-wise it went much […]
Mathematicians Go Hollywood
Did you know that in 2008 a mathematician won an Academy Award? Do you know how to model realistic hair for animation movies or a bomb deflagrating for an action movie? Or you simply need some effective active contour segmentation method? All these questions have in common an effective, yet intuitive, mathematical framework: level set […]
Coding coding coding
Despite the confusing title, in the past days I have been coding. A lot. Even though I am dying to leak information about what exactly I am working on, I still need to wait few weeks to reveal. I thought anyway to write something about programming from the perspective of an applied mathematician. Research forces you […]
Tweeting for Real Scientists: aftermath.
My week as curator of the Twitter channel @realscientists has just ended. It was refreshing and a lot of fun. I had the chance to review my own work from a fresh perspective and to check out old problems I didn't read about for a while. For those who don't know what Real Scientists is, I […]
4D tomography: walkthrough of my project - part 3
Here comes the final part of the walkthrough of my current project on dynamic sparse tomography (see also part 1 and part 2). In the previous post I left the question of the choice of the cut-off function hanging. In a classical level set method, would be the Heaviside step function. The Heaviside function is […]
4D tomography: walkthrough of my project - part 2
After talking about motivation (see the first part and then part 3), I will now go into details with the mathematics foundations of the project. The novel tomography reconstruction algorithm I am contributing developing is based on a level set method approach. Level set methods A level set method is an elaborate, yet geometrically intuitive, framework to deal […]