April 2011

Master’s Thesis

It’s been some years now since this was produced, yet working with type systems recently I figured it was worth putting my master’s thesis online as well. It didn’t contain any break-through results, but I remember being content with its ridged formulations and proofs, and its self-containment — it even including a section in the appendix outlining the entire approach in the form of a tiny and easy-to-understand type system.

From the abstract:

In this paper we give a type inference algorithm for a type system for a pi calculus. The effect type system with dependent types guarantees that well-typed processes respect an authenticity property expressed as correspondences.

Given a process and a type context we generate constraints that are satisfiable if and only if the process can be made well-typed under the context. […] The output of the algorithm can be used to efficiently construct a proof of safety in the form of a derivation tree.

Experiments with a Caml implementation have shown that the algorithm performs well in praxis.

A small paper based on the thesis was presented at Nordic Workshop on Programming Theory 2008 (NWPT’08), and it also served as the basis for a later paper on a more advanced type system, presented at Workshop on Foundations of Security and Privacy 2010 (FCS-PrivMod’10).


Exhibition: Growth

One of my favourite photo blogs is PHOTO.fr, who a few weeks ago mentioned the Growth exhibition currently on display at Passage de Retz in Paris. I went there today and found it refreshingly good.

The first thing intriguing my attention was the photos online. Not really looking into the concept I simply liked the photos for their content and style.

My attention was further raised entering the exhibition and reading about the exhibition and the project. Mixed from the project’s website:

The Prix Pictet has a unique mandate — to use the power of photography to communicate vital messages to a global audience. The goal is to uncover art of the highest order, applied to confront the pressing social and environmental challenges of the new millennium.

The theme for the third cycle of the Prix Pictet is Growth. At once a blessing and a curse, Growth, in all its forms, presents one of the great conundrums facing humanity in the early decades of the twenty-first century. From the dizzying expansion of our cities with their ever increasing dependency on scarce natural resources to the relentless growth of populations and the need to feed ourselves.

Here’s a great purpose for taking photos, a clear illustration of letting an idea drive and decide what photos to take and how! In trying to find my photographic identity I’ve run into the typical problem of working within a frame too broad. As I’m starting to experience, your creativity suffers from this and what you produce is too scattered to reach the depth required to make it interesting. I’m not sure Growth is the right frame for me but it does provide an example from which to draw some enlightenment and inspiration.

My attention was cemented upon seeing the prints. The first we saw were huge prints of three photos from Michael Wolf’s Architecture of Density, each filling up 3×4 meter on the walls. From the leaflet:

Hong Kong is one of the most densely populated metropolitan areas with an overall density of nearly 6,700 people per square kilometre. The majority of Hong Kong’s citizens live in flats in high-rise buildings whose units can house as many as 10,000 people. [..] Bits of laundry and hanging plants pepper the tiny rectangles of windows – the only irregularities in this orderly design. The images [..] give us an inkling of what our cities could look like if growth continues unchecked.

In this size the photos were really powerful.

The photos from Chris Jordan’s Midway: Message from the Gyre left an equally big impression. From his website:

On Midway Atoll, a remote cluster of islands more than 2000 miles from the nearest continent, the detritus of our mass consumption surfaces in an astonishing place: inside the stomachs of thousands of dead baby albatrosses. The nesting chicks are fed lethal quantities of plastic by their parents, who mistake the floating trash for food as they forage over the vast polluted Pacific Ocean.

Along with the photos, each artist also provided insight into his or her interpretation of the theme by a small accompanying text. I was particular fond of Chris Jordan’s text:

For me, kneeling over their carcasses is like looking into a macabre mirror. These birds reflect back an appallingly emblematic result of the collective trance of our consumerism and runaway industrial growth. Like the albatross, we first-world humans find ourselves lacking the ability to discern anymore what is nourishing from what is toxic to our lives and our spirits. Choked to death on our waste, the mythical albatross calls upon us to recognize that our greatest challenge lies not out there, but in here.

It’s stories of that calibre I want to have behind my photos! :)

Last but not least, winner Mitch Epstein had two great photos in the form of large prints from his American Power series, illustrating the power industry’s intrusion on American towns and landscape. Really good as well.

Going to see The Thermals

I’m leaving for Paris today, partially in order to catch the Thermals concert on 6 April. Finally! I’ve been waiting for this ever since they kicked arse at Point Ephémère a bit more than a year ago in the autumn of 2010. I even wrote them an email at some point asking when they would come back to Paris. They thanked me for the interest and said spring 2011.

So why the huge interest? First of all, the music is quite energizing. In the morning, during the day, and after work, putting on a Thermals album never fails to raise my beat and make my feet follow the drums. If not because of the soft punky energy it emits then because of the smile their raw naive tunes bring to the face.

Secondly, at the concert last year I couldn’t help but fall in love with them. They seemed genuinely happy to be there. And a bit nerdy in a very lovable kind of way – the drummer never parted with his silly happy smile; the bassist, living a bit in her own world, alternated between jumping and experimenting with monitor feedback by bringing the bass close it. Maybe the lead singer came off a bit arrogant – or maybe I read it in an interview later – but still in a cute younger-brother-trying-to-show-off kind of way. During the concert they managed to create a connecting with me that I only rarely get at a gig (Mumford & Sons did it as well). This was in sharp contrast with the Arctic Monkeys I saw a few months after and who seemed quite arrogant and almost annoyed that they had to come and play. Experience wise the 35€ I paid for this seemed up side down with the 15€ I paid for Thermals.

Joy Division has later joined them but Thermals were the first band to make it to my list of tracks I would play cover versions of, if I ever am to go on stage doing that. In fact, together with Springsteen and Clash I had Thermals in mind when I went shopping for my first guitar and later started to play.

I can’t completely rule out that my romantic memory of the concert may be coloured of me being new and naive in Paris. But  expectations are high!