Heat map visualization of sick day trends in Finland with R, ggplot2 and Google Correlate

Inspired by Margintale’s post “ggplot2 Time Series Heatmaps” and Google Flu Trends I decided to use a heat map to visualize sick days logged by HeiaHeia.com Finnish users. I got the data from our database, filtering results by country (Finnish users only) in a tab separated form with the first line as the header. Three columns …

Setting up and securing web server (+MySQL +Rails/PHP) on Ubuntu 10.04 LTS

After repeating these operations many times in various setups, I decided to create a public set of instructions and share them with the world. This should be suitable for most of the simple web sites, utilizing Ruby on Rails or PHP.

The setup works on Ubuntu 10.04 Server LTS (scheduled end of life April 2015). Other components of the setup are Nginx as the web server, Phusion Passenger as application server.

I’m using this setup most often on Linode VPS, however none of the instructions are Linode specific.

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Book review: European Founders At Work

A book by Pedro Santos follows the format of Jessica Livingstone’s “Founders at Work”, offering a series of interviews with the founders of European start-ups.

Entrepreneurs, such as Illya Segalovich (co-founder of Yandex), Loic LeMeur (founder of Seesmic and LeWeb), Peter Arvai (co-founder of Prezi) and many others (see full list on the book’s website: www.europeanfoundersatwork.com) tell about how they started, built, pivoted and drove their businesses to success.

The book gives a unique first-hand perspective on how to grow a successful business from Europe, what is the importance of US market, what are the challenges European start-ups are facing and what are the competitive advantages of being in Europe.

It is an inspiring book, and it is very relevant to European entrepreneurs. While stories of US start-ups quite often start with “we got $N mln in funding and started growing from there”, in Europe it’s more about bootstrapping and building a profit-generating machine. I would definitely recommend it to anyone who is thinking of starting a technology company in Europe or is already running one.

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Informal notes from Strata 2012 conference on Big Data and Data Science

It’s been almost a month since I came back from California, and I just got around to sorting the notes from O’Reilly Strata conference. Spending time in the Valley is always inspiring – lots of interesting people, old friends, new contacts, new start-ups – it is the center of IT universe.

Spending 3 days with people who are working at the bleeding edge of data science was an unforgettable experience. I got my doze of inspiration and got a lot of new ideas how to apply data science in HeiaHeia. It’s difficult to underestimate the importance data analysis will have in the nearest years. Companies that do not get the importance of understanding data and making their decisions based on data analysis instead of gut feeling of board members/operative management will simply fade away.

Unfortunately HeiaHeia was the only company from Finland attending the conference. But I’m really happy to see that recently there are more and more signals that companies in Finland are starting to realize the importance of data, and there are new Finnish start-ups dealing with data analysis. I believe that Finland has an excellent opportunity to have not only a cluster of game development companies, but also big data companies and start-ups. So far it seems that the Valley, London and Australia are leading in this field.

By the way, Trulia (co-founded by Sami Inkinen) had an excellent demo in the halls of the conference venue – check it out in their blog.

Below are my notes from the conference – I added presentation links and videos that I have found, but otherwise those are quite unstructured. There were multiple tracks and it was very difficult to choose between them. Highlights of the conference are talks by Avinash Kaushik, Jeremy Howard, Matt Biddulph, Ben Goldacre, and Alasdair Allan and the Oxford-style debate on the proposition “In data science, domain expertise is more important than machine learning skill.” (see videos below).

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Book review: The Information Diet: A Case for Conscious Consumption

I read “Information Diet” by Clay Johnson last Christmas. Central ideas of the book: – information is like food – bad consumption habits are bad for your health – it’s too easy to get yourself into information bubble: “When we tell ourselves, and listen to, only what we want to hear, we can end up …

REE segfaults when Rails application has too many localisation files

We ran into an interesting problem – at some point of time our Rails application started to fail occaionally because of REE segfaults on startup. Even starting the console with ‘script/console production’ was occasionally failing with REE segfault. Application was growing, new features were added and segfaults started happening more and more often. There was …

Pitfalls of Rails fragment caching with memcached

Fragment caching is a powerful technique for improving performance of your web application. Rails site describes in detail how to apply this technique. Rails are providing developers with really excellent abstractions, but it’s always good to know what’s under the hood and how it all works. There are a few things that might potentially cause …

Notes from Gothenburg – Nordic Ruby 2011 conference

Here are my notes from Nordic Ruby conference in Göteborg, Sweden.

I’d like to say big thanks to the organisers of the conference (especially CJ @cjkihlbom) – everything went really smooth, even though there’s been 150 people attending this year compared to 90 last year.
Some points that I’d really like to highlight are:

  • a lot of time to meet people and discuss: 30 minutes talks followed by 30 minutes breaks, no q&a – those who had questions had an opportunity to talk to the speakers during the breaks
  • venue was great (of course, the boat 🙂 – there was enough space for everyone to move around, but at the same time it was compact enough not to get lost also everyone had an opportunity to have lunch and dinner together
  • “job board” a huge white board where anyone can post information about open positions in their companies – it got filled withing firts few hours – job market is really hot
  • lightning talks that any participant can give – 5 minute talks in the end of the day – it was really great
  • real coffee 🙂 espresso, latte, cappuccino, americano – you name it – professional baristas were at your service
  • 5K Nordic Ruby run organised on the second day’s morning

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