Parc Oka for the Canada Day Long Weekend

We went on a bike & camping trip to Parc Oka for the weekend and documented the trip with some photos.

Originally we were supposed to take a train to and from Deux Montagnes, which would have made this trip very easy, but the AMT had some unannounced line work. So Erin threw together some last minute improvisational plans and the "to" portion of our trip included a horrific STM then CIT commuting.

We ended up biking from St. Eustache, which was only about 5 km further. Taking the AMT from Deux Montagnes on the way back was much more accommodating for our bikes, and our bike-seats and Croozer full of camping gear / 3yo child.

I also traced our trip using MyTracks for Android, and it worked quite well. Considering how much I'm on my bike, MyTracks is practically like a personal trainer given that it records all of the stats you can imagine (latitude, longitude, bearing, speed, elevation, time, etc).

It was the perfect weekend to get away, and Parc Oka was awesome. The water provided an excellent escape from the heat that weekend.

Pre-Departure Updates

That last few weeks have been insanely busy for me.

First, I sold all of my furniture and said goodbye to my former apartment in Kiel, since I'll be leaving for Montreal on Tuesday (yaaay!!). Since then, I've been couch-surfing at a friend's apartment down the street. Moving out was a huge undertaking, and I'm quite relieved that its over. There's something extremely liberating in a sort of Zen-Buddhist way about living out of a backpack.

Also, I've been putting in crazy amounts of overtime on my thesis project, which is coming along spectacularly. I've been meaning to write a blog post about it, without giving away too many things prematurely (call me superstitious, but I feel it could jinx me in the end). All I can really say at the moment, is that it's really pushing the physical limits, and that the antenna actually depends on materials being in the near-field. I will allow myself to expand on this point alone for clarification. For most people with any background in physics or engineering, it's common knowledge that EM wave propagation slows down in matter. The wave propagation velocity is equal to the speed of light in free space, but in any material with a relative permittivity greater than 1, the propagation velocity decreases. However, since the measure of time remains constant, the frequency remains constant. Subsequently, in order to maintain equality, the wavelength (L) shrinks according to the equation L = cr / f. A really fantastic consequence of this (antennas not-in-free-space), is that an antenna tuned to a specific frequency surrounded by a given material is often a significant fraction smaller than the equivalent antenna in free space. The resonance remains the same regardless of the angle of incidence (although directional gain is clearly affected). Half-space (or really multi-space) simulations of my antenna design (thus far) have allowed me to reduce the antenna size by a factor greater than 2! Without this near-field effect, it would literally be impossible to create an antenna that resonated in my required frequency range (the lower frequency bound being inversely proportional to the antenna dimensions - the limiting factor). This last week, I've been working on accurate 3D modelling of a planar antenna projected onto the surface of a half-ellipsoid (in order to approximate the inner curvature of a prosthetic eye), which will be the final addition to my simulation. I will then need to do some fine-tuning of the antenna dimensions (this will likely be some sort of constrained numerical optimization, perhaps MMSE), and finally I'll be able to build a physical prototype. Its safe to say though, that it has been far from an easy task. Limitations of our FDTD software and API did pose a major hurdle at one point. I've been doing a lot of the 3D modelling lately in Matlab (with its severely limited Dulauney triangulation capabilities) but I will eventually (or rather in the next week or two) have to write a Dulauney triangulation module in pure Python to interface with the FDTD API. I'm not a huge fan of Python, but I do what I must. In short, I really think that this antenna will be the first of its kind. I can't imagine that anyone has ever created such a specific design, just as the Eyeborg project is equally the first of its kind. The remaining things will be a bit of an exercise in reverse engineering, since I received absolutely zero assistance (so far) from WUSB transceiver chip vendors. I'll also need to improve the state of the Linux WUSB stack. Hopefully when chip vendors see a demonstrated prototype they'll be more inclined to cooperate with us on the Eyeborg design.

My GSOC project was on a bit of a hold this week, since it was my last week in Germany and I needed to focus on thesis work before my flight on the 15th. However, tonight I should be able to accomplish the tasks that I set for myself last monday. Keep an eye on my GSOC blog tomorrow for my weekly report.

Lastly, I leave you with a token of motivational music that should indicate my my overly-caffeinated state of late. Major thanks go to the countries of Ethiopia (for producing such great coffee), and Austria (for inventing RedBull).

Canada Rejects Business Method Patents

Here's a link to an interesting article by Michael Geist [via Slashdot].

I completely agree with the ruling, and am very glad that we still don't patent software in Canada.

Montréal: Hacking the Kernel

So I've been back in Canada for slightly longer than a week and I'm working full time for Visible Assets until the end of September.

I've decided to postpone my flight back to Hamburg until the end of September so that I can spend a bit more time with friends and also get a bit more done for work.

Right now, I'm sitting in Montréal at Erin's place. It's been nice to be back - actually, I think I'm suffering less culture shock in Montréal than I would be in Toronto. To tell you the truth, I think mon fronçais went straight down the garbage chute since October, as if German had totally displaced it in my brain. I really think that I'm going to have to work hard at it when I get back to Canada full time, and it would be nice to work towards some sort of bilingual certification or something.

A good friend of mine from the undergrad days, Ed Cote, is in Montréal at a conference presenting some of the work he's done at Queen's, in his master's program. He just finished this past semester (I'm jealous!). Today we're going to be meeting up for a 'cinque à sept', which basically means to have a few drinks at the end of the work day. I'm looking forward to getting out on a patio and having a couple of cold ones, especially in this heat!

For the next month and a half I will be porting much of the code that I've done in user space to kernel space - well, as much as possible, i suppose. Things that I won't be able to convert to kernel space are services and so on.

Particularly, one thing that I'm working on at the moment is a virtual block device that represents tracked / timed connections to the blaster device. What's particularly strange about this, is that I'm hijacking a serial device from within kernel space, albeit with a removeable module.

So far, it's going pretty well and I even have my module initializing the uart, but I've encountered a couple of segfaults. Luckily, I'm testing all of this using Qemu ;-)

Update (2007-08-09): I've managed to fix all segfault issues with serial hijacking by exporting a function init_tty_dev, which is just a wrapper for init_dev, in drivers/char/tty_io.c . Now the uart_driver->tty_driver->tty_struct array will contain a non-NULL pointer to a tty_struct which init_dev initializes. This must always be released with release_tty_dev( struct tty_struct * tty, int idx ) when the module unloads in order to return the refcount.