Archive | July, 2013


30 Jul

Officially I’ve been teaching subjects that had a MATLAB component in it for the last 2 years (this semester would be my third). The problem is that I’ve never really learnt MATLAB. I had to use it briefly for my Linear Algebra course, but all we had to do what copy down commands. In the course I’ve been teaching, MATLAB has been a side thought and students have been able to successfully ignore it. However, this semester, MATLAB is the very first thing we are doing, so I got some hopes, not particularly high mind you, that students might actually end up using it a bit rather than just ignoring the labs.

Having said that, I am a coder. Just because I don’t really know MATLAB, doesn’t mean I have no idea what I’m doing. Its more that MATLAB does odd things. Like to access  vector (which as far as I’m concerned are just arrays) elements, you use round brackets. How am I meant to remember that when I only use MATLAB a few times a year?

Here to hoping that students are willing to actually play with it and learn.


First day of semester

29 Jul

In a way I miss first days of semester. Catching up with friends, new subjects and good intentions. Now the first day of semester means no parking and large lines for food (at least there is more food around). The first day of second semester isn’t quite as so as first semester. Most students have been around for at least one semester, so they are no longer so bright, enthusiastic and dressed in their most fashionable clothes. They have all become a bit disenfranchised with the whole system. Oh well, my first tutorial for the semester (actually lab) is tomorrow. We are throwing them in the deep end and getting them to use matlab. I’m not sure how that will go, but it will be fun and somewhat frustrating.

What always strikes me about the first few days of semester is how some of the women students dress. Yes, those 10cm heels look good, but how do you expect to walk? Oh well, they learn soon enough. However, my favourite story:

I was walking to uni. About 100m ahead of me I saw a woman who didn’t appear to be wearing pants. I got closer, it appears that she was wearing flesh coloured tights. Getting closer I realised that you could see her underwear right through her tights. As I was overtaking her, I saw she had “Wrong way, go back” written on her undies. I’m almost certain that this was her first day at uni. I really wonder how it went for her.

Booth Babes at PAXAUS

26 Jul

Two weeks ago I attended the Australian Mathematical Sciences Student Conference, followed up with a trip to PAXAUS. One thing PAX events are known for are no booth babes. However, in the exhibition centre, there were both babes. Multiple companies in fact. There were the military ladies in short skirts and heels promoting world of tanks, the police women who somehow had a connection to Sennheiser headphones and some others wondering around in black and orange catsuits with bare tummies. The world of tanks were called out on it and were forced to put in tights (I noticed that, I thought it was because they were cold). A few other media outlets have commented on the booth babes. The Guardian had a good mini interview with the world of tanks guy: they obviously didn’t get the issue with booth babes. Kotaku missed the point.

The problem with booth babes isn’t that they are showing too much skin or that they are inappropriate viewing for young children.

There are two sides to the problem. First, your product should be able to sell itself. Why are you needing to rely on female skin to sell it? Who are you trying to attract? At PAX, Sennheiser was trying to sell headphones with female police officers. I had no idea those two were connected. Thinking back to what was probably the Sennheiser area, I thought it was just a game relating to police officers.  I might have actually looked at them I knew they had anything to do with headphones and if I thought they were marketing to me at all.

Secondly, for a female to sell your product, why does she need to be turned into a booth babe? At all the stands that had babes at PAX, I did not see one male dressed nearly as provocatively as the females. Why is that? Is it because women are some how lesser and need to be attractive in order to be able to sell a product? Does the company also think I’m not worth attention unless I’m dressed in a similar way?

Booth babes make me uncomfortable. Its more that I perceive that they are hired to attract men to the stall, I’m not a man, ergo, the company does not wish to attract me. Its that I feel like I’m an object when around them. I would like to look at the stand, but I’m not feeling welcomed.

I applaud the Penny Arcade guys for not allowing the booth babes. I despair at the companies and the media who don’t understand why.

Woman in Science

12 Jul

It's pi plus C, of course.

My experience as a woman in maths has been positive. Through out my undergrad no lecturer made me feel like I was any different from the others in the class. The only real negative were men in my computer science class stop being friends when I got with my partner. Oh well, they weren’t really friends anyway. Where I did my undergrad was slightly unusual in the number of female staff: over five compared to barely three at my current (larger) school, and other people are impressed with this number. I’m not sure if the number of female staff helped me in any way (like make me feel more normal, helped other perceptions to people in sciences).

My current situation is also positive. I do feel at times that other PhD students feel that I’m inferior. This is mostly because they disregard things that I say, try and change my mind when I’ve quite clearly said no and are more likely to ask other people questions. Nothing too explicit, but still enough to annoy me. Anyway, for me, that is just one person.

Unfortunately, there is more than one person like that. Consider this study. The same application, just the name  changed from female. The females were considered less able and would be offered less pay.
This (trans)-man experience showed that people do treat men and women differently.

I don’t think many of these things are conscious sexism which makes it even more insidious. The only way to combat it is to actively pull up people who don’t realise that they are being sexist. Which is hard: I haven’t properly pulled up the guy I described earlier.  What makes it especially hard, is when you point out the issue, you get told that you are being an hysterical female. Having men aware of these issues who are also willing to pull people up on these issues are essential, if we want to get anywhere.

My favourite saying/quote/sentiment at the moment is “How do you expect to be competitive if you are only using half the population?” I most recently saw it in Lean In, and it is true for all areas (how can we have the best parents if we only consider mothers?). But if we really want to have the best academics, why the discrimination against half the population?

The Feasibility Pump

8 Jul

The Feasibility Pump is an heuristic used in Mixed Integer Programs (MIP). Its aim is to solve the satisfaction problem, i.e. find a feasible solution to the MIP. We want to find this initial solution as we can then start cutting on the branch and bound tree and apply other heuristics such as RINS,  which uses local search to find a better solution. Ideally we would like to not take very long in finding this solution, but at the same time we would like a solution with a reasonable objective value.

This heuristic divides the MIP into two spaces: the LP polyhedron and the space of integer (or binary) points. It first finds the LP point, which  becomes the fractional solution $x$. We then find the closest integer point by simply rounding each variable to the nearest integer. We now project back onto the feasible space by solving the LP $\sum_{j} |x_j – x_j^*|$ with the same constraints as the original MIP. We now have an integer point $x^*$ and we know its distance from the LP polyhedron. If the distance is 0, this means that out integer point IS the fractional solution, which means we have found an feasible point. Most of the time, this isn’t the case, so we need to project back (by rounding) to the integer space.  And we repeat this practice until there is a solution.

Well not quite. FP suffers from cycling. This is where it alternates between the same integer for fractional solutions. To combat this FP has perturbations and restarts. A perturbation is simple just shifting a few of the variables slightly in order to kick it out of the cycle. After a few perturbations, if cycling is still detected, a restart is performed which causes all the variables to be essentially randomised. To detect cycling FP says the distance calculated from the integer to fractional calculation must always be decreasing.

As far as I can work out, the idea behind the FP was “lets try this crazy idea out, hey look, it actually works!”. In this first paper, there wasn’t much theory why it actually works. As it turns out, pure mathematicians, have been looking at projection algorithms for a while, and have a few results proved about them. Mostly in convex spaces and/or Hilbert spaces. There is now research going on using these different projection algorithms. But still mostly it is a bit of black magic and we don’t know how far we can push these algorithms.

This is my current lot of research: looking at different projection algorithms and the feasibility pump.


Getting stuck into writing

5 Jul

I have a conference paper due on Sunday. I’ve known about this paper for weeks, but I’m a masterful procrastinator. On the plus side, I’m really getting stuck in my writing. The problem is, I only ever seem to get in this frame of mind when there is an imminent deadline. Which is really not a good state of affairs, especially when I have another paper to write and thesis chapters to get through. I need to be able to keep up this writing momentum. I’m thinking at this stage that I need to dedicate my mornings to writing, and my afternoons to doing some research. Dedicating days at a time of writing just mean I get burn out and I end up procrastinating.

My hints for writing:

  • Dedicate some time each day and actually do it. This time should be for writing as in creating new words on paper, not editing the words you already have
  • Write as you go. Don’t try to write about what you did 6 months ago as you really don’t remember what you did and writing about it  will give you ideas that you should have thought about 6 months ago.
  • Work out how you work. I’m very much a big picture top down approach. I first need to write an out line (in bullet points) of things I need to cover. Then each point gets points on things I need to  cover to get to that point…. until I get to the stage where each point is. For me, a blank page that I need to fill up with properly structured sentences is scary,   filling it up with poorly structured grammatically challenged points is easy. Your millage may vary.
  • Write a talk. I like to keep my slides to be quite bare with minimum amount of words, which means I can focus on what I need to include and the structure rather than the actual words.
  • Try a standing desk. For some reason I work much better when standing. I’m much more focused on what I’m doing and less easily distracted. I can also listen to music and dance as I go.
  • Use the pomodoro technique. This technique is to set a timer for 25 minutes, work with no distractions for that time, then have a 5 minute break. Continue this for 2 hours and then have a longer break.

Looking at all these hints, it seems that most of them are just tricks to get you started in the writing. Once you start to write, it becomes easier. Now I just need a trick to keep the momentum going.

Moving: the joys of a share house

4 Jul

I live in a share house. This is quite typical of a PhD student: while we get money, its not really enough to rent a place of our own, so we share. I’ve been in three different houses in the last 2 years.

House 1: sociopathic housemate(s). In this house there was a couple (one of whom was the sociopath, the other I’m not sure) that sublet the two spare rooms. The internet went out and he claimed the ISP suspended it, but never provided proof, refused to talk about, I and the other guy renting tried to talk to him about it, he kicked us both out over the long weekend while we were visiting our (different) families.

House 2: this wasn’t actually a bad house. Just 5 people sharing, not much interaction. Some of them managed to flood the bathroom on a regular basis. For me it was emergency accommodation after the previous place, it was two expensive for the long term.

House 3: this is where I am currently. Moved in with a sort of friend. Two randoms had the other rooms. It was fine for the first year. This year sort of friend got a real adult full time job. Which meant he became incapable of cleaning dishes within 24 hours of using them and remembering to pick up after himself. Of course instead of whinging here, I should just be straight out and tell him, which I actually have. It just makes me feel like his mother. And I don’t won’t children at the moment. The other problem here is the randoms: one is an ex-student (and not a very good one at that) which raises questions of conflicts of interest. The other smells and doesn’t talk to any one.

Now I’m looking at moving out. My problem is that my place is actually quite good, present company excepted. Its a large room, decent public transport and bike paths, close to the shops,  and close to the uni and a good price. At the moment my current choices for a new place is about 8km from the uni, sharing with one other person (with internet) or close to the uni and sharing with 2 others (no internet). The later does seem better, but involves sharing with undergrads, who are, well undergrads.

I’m trying to kid myself into thinking that living further away from the uni may get myself more organised in the morning and mean more  bike rides, rather than more time on public transport. Also trying to kid  myself into thinking that I really don’t have much stuff and it won’t be a hassle to move.

I have a love/hate relationship with this move. I want to move, I’m not happy where I am. But I’m worried that moving will put me in a worse position.