Nicolas Kruchten

Nicolas Kruchten
writes code and visualizes data
in Montréal, Québec, Canada.

VisMtl #5 Roundup

VisMtl #5 Roundup

I recently organized and MC’ed the fifth Visualization Montreal meetup, and I think it was a great success! The concept was to have a series of 7-minutes-max flash presentations from Montrealers where each one would show off a single visualization project. The rules were: no slides, no tools, just one publicly available data visualization. We had 12 presenters including me, with a good mix of types of data and visualizations. Below is the list of visualizations that were presented, and you can find photos of the event here.

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VisMtl: Canadian MPs 2012 Visualization

VisMtl: Canadian MPs 2012 Visualization

The visualization I presented at VisMtl 5 was entitled “Canadian Members of Parliament in 2012 by Province, Party, Age & Gender” and is shown above.

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The Programmatic Waterfall Mystery: Solved


A recent article on AdExchanger asks “In the supposedly super-efficient world of RTB, why would publishers continue to waterfall their demand sources?”. The article goes on to say that the publisher’s justification is “Because it works” but that “Any economist could tell you that this is a bad idea”. I’m not an economist but I can still pull together enough auction theory to show that this practice isn’t necessarily a bad one today.

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PAPIs.io 2014: Behind the scenes with a Predictive API


I gave a talk at in Barcelona at the PAPIs.io 2014 Predictive APIs conference last November.

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Interactive Subreddit Map with t-SNE

Interactive Subreddit Map with t-SNE

For part of my presentation at Montreal Python, I made an interactive map of the various sub-sections of the website Reddit (called subreddits). You can take a look at the interactive version or see a static annotated one above. The interactive one includes basic info on how I made it and full details are in the presentation. I got some nice comments in the /r/DataIsBeautiful subreddit post

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Montreal Python: Unsupervised ML with scikit-learn


I gave a talk at Montreal Python on Data Science and Unsupervised Machine Learning with scikit-learn. The video is above and I posted all of my presentation materials online.

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Arbitraging an RTB Exchange


Last week, Bloomberg came out with an article on RTB arbitrage, which included a couple of sentences that made it sound a lot like it was possible to front-run an RTB auction: “Some buy from an exchange and sell it right back to that very same exchange” and “Some agencies are poorly connected to exchanges and can’t respond to a first auction in time, allowing middlemen to buy and flip within the same market”. This seemed surprising to me at first, given that all auction participants (as far as I know) get the same opportunity to bid on an impression, so how could you make money buying and selling the same impression on the same exchange? Upon further thought, however, here’s a theory about how it might work.

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VisMtl: Maps, Tools, Stories


I gave a talk at Visualization Montréal entitled Maps, Tools, Stories. Check out the synced slides and video!

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Visualizing High-Dimensional Data in the Browser with SVD, t-SNE and Three.js


Data visualization, by definition, involves making a two- or three-dimensional picture of data, so when the data being visualized inherently has many more dimensions than two or three, a big component of data visualization is dimensionality reduction. Dimensionality reduction is also often the first step in a big-data machine-learning pipeline, because most machine-learning algorithms suffer from the Curse of Dimensionality: more dimensions in the input means you need exponentially more training data to create a good model. Datacratic’s products operate on billions of data points (big data) in tens of thousands of dimensions (big problem), and in this post, we show off a proof of concept for interactively visualizing this kind of data in a browser, in 3D (of course, the images on the screen are two-dimensional but we use interactivity, motion and perspective to evoke a third dimension).

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Big Data Week Montreal: From Big Data to Big Value


Video and slides from my talk at the kickoff of Big Data Week Montreal 2014.

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© Nicolas Kruchten 2010-2017