Cambridge Interview Video

Jake and I have made a recording of an undergraduate interview (not a real one!). Jake has edited it down and added some very useful commentary so you know what’s going on.  Hopefully it might help demystify the process for people who are applying to Cambridge.

University teaching prize

This year I was privileged to be awarded one of the University teaching prizes.   They only give out 12 awards a year and so given that there are around 1,600 academic staff in the university I was very pleased to get one. 

My nomination was from the Computer Laboratory for the work I’ve done with the programming lecture courses I teach.  For the first and second year Java courses this involved moving away from lectures to practical sessions with automated unit tests so that students can work at their own pace and actually practice on large programming tasks.  I also teach the second year course on Prolog and in this course I replaced the lectures with video recordings – the idea was to investigate how a MOOC would work in tandem with the Cambridge supervision system.    All of the above work I did in collaboration with Alastair Beresford who is a senior lecturer in the department and a fellow of Robinson College – he won a teaching prize too this year for this work.

Here’s a picture of me getting my award from the University’s Vice Chancellor Professor Sir Leszek Borysiewicz:

Image

You can see more details about the awards on the University news pages

Second and third year exam results

Congratulations to the second and third years on their exam results!    Overall Queens’ has achieved five 1sts, five 2.1s and 1 2.2.  Not only are these results excellent in their own right but almost everyone has improved (relative to the rest of the year group) from last year.

Special acknowledgement goes to Tom Powell and Stephen Cook who also had their final year projects commended by the examiners.

Now we have to wait for the first year results to come out on 30th June….

Computer Science Annual Dinner

Sunday 18th May was the Computer Science Annual dinner for Queens’ undergrads, graduates and supervisors.  One of my favourite things about the dinner is getting a chance to catch up with our graduates and with a total 63 people attending it was the biggest I’ve been to.  There was a very relaxed and social atmosphere and all the different groups of people got on really well.

IMG_3285

We were especially pleased to welcome Demis as our guest of honour this year.  Demis graduated from Queens’ in 1997, went on to do a PhD and then founded DeepMind Technologies – recently acquired by Google.   Demis featured in our elevator pitching session a few weeks ago (can you spot it?) and he was in hot demand from the more entrepreneurial undergraduates.

This year’s organizers, Mistral and Eduard, did an excellent job.  Everything ran smoothly from the Champagne reception (photo below), to formal hall, to the extra food and drink in Old Hall to round the evening off.

IMG_3279

I complete the takeover as Director of Studies this year and so Robin Walker gave his final Computer Science Dinner Speech.  Next year I’ll have to do it all by myself although Robin admitted he might come along if we extend an invitation.

The dinner is greatly enhanced by some generous sponsorship by both companies and individuals.   The companies sponsoring us this year were: Jane Street, Skin Analytics, Coherent Graphics, G-Research, Bromium and Acano – all of these were represented at the dinner by a Queens’ graduate or two.

James King’s AI Playlists (james.eu.org/download)

It’s an hour after the last exam and people are coming back to my place to celebrate. However, my choice in music is terrible, and I don’t want to kill the buzz by playing things no one else likes. The solution: have a computer do it for me.

reassuring

James developed a music analysis platform for his part III project, which provides a q-learning hierarchical-clustering Markov-model solution to the problem of playlist creation. The idea is to it separate music that sounds similarly into clusters, so that if there is one track in my library that I can identify as socially acceptable, the algorithms will find others like it as well. Additionally, James used modern AI techniques to model how I interact with my music in order to produce better recommendations based on different user moods (e.g. revision vs. hacking). Here’s an overview of how it works:

Feature Extraction (Learned in Part II)

The first step is to take a song and turn it into a set of descriptive features. He takes in music files that look like:

signal_example

And by doing autocorrelation, a method of exaggerating repeated features and suppressing others, he turns them into signals like the following:

sinal_autocorrelated

The high peaks labeled “good match” are then used to identify songs.

Clustering (Learned in Part IB)

Since the first goal of the project is to divide songs into clusters (playlists) based on similarity, these features need further processing. In particular, a clustering algorithm, which takes a set of unorganized points and divides them like this:

clustering_example

Each point here represents a song, and they are currently being clustered by two different features. However, this type of clustering doesn’t capture the notions of genres and subgenres, so James opted for a more refined hierarchical clustering algorithm, which does stuff like this instead:

hierarchical_clustering

What to Play Next

At this point, the algorithms have everything grouped into playlists and subplaylists, using hierarchical clustering on the characteristic features of each song. The next part of the problem is figuring out which song in the playlist to play next, given the previous song. This is done with Markov Models.

Markov Models (Learned in Part IB)

A Markov model shows how states are probabilistically linked, making the assumption that the next state is entirely dependent on the current state. So for example (probabilities are heavily adjusted because Andy can see this):

out
If I’ve been revising, it’s highly likely that I’ll keep revising, with only a tiny chance that I’ll end up going to a pub. And even if I make it to a pub, I definitely wont go to another one afterwards; instead it’s straight to sleep.

James took this and replaced the states (revising, sleep, go to pub) with clusters and subclusters in his model. The model then contains the likelihoods of switching artists, genres, and different songs within the same genre. It is initially created to make similar songs likely to be played in sequence, but then uses AI to learn a better way of doing this based on user actions.

The AI – Q-Learning (Learned in Pat II)

This part is more involved, so I can only give a general overview.

In essence, Q-learning is a method of teaching a computer to perform some task by shouting at it when it gets it wrong and giving it a cookie when it gets it right, learning by reinforcement. In this case, the recommender did a good job if the user listens to a track all of the way through and a bad job if the user skips over it after the first few seconds.

With this information, the system can update the Markov model describing how the next song is chosen. For more information, here’s a link to our AI II course’s notes on the topic (page 339): http://www.cl.cam.ac.uk/teaching/1314/ArtIntII/ai2-2014.pdf  

Now that James has done the hard work for us, you can try out his system at james.eu.org/download to see for yourself how it works.

The ‘Untrusted’ games

Last Wednesday all Queens’ Computer Science students participated in a team programming game with delicious prizes offered by Dr. Rice.

The evening started off nicely with -guess what- special prizes offered for the best team name and for matching outfits. Team “’) DROP TABLE PARTICIPANTS; – -” managed to secure first place. Even though they were not the only ones trying to do that(!) they were the ones with the closest correct SQL injection (fortunately Google Forms is not vulnerable to these attacks).

XCKD SQL injection

Teams with similar hats, similar shirts and/or “fancy” dressed were awarded prizes as well.

1 2 3 4

The actual programming contest consisted of playing the game Untrusted and seeing who manages to finish it first. This is a puzzle game, where you have to write/complete, under some limitation, Javascript code in order to pass different levels. The game proved to be quite tricky and quite entertaining. I especially liked the level – sorry for the spoiler – where your player was in the forest and you had to regenerate the trees until you can move him and reach the exit.

Overall the contest was useful since we learned a bit of JavaScript – for those who didn’t know it already- and got to work in teams. Prizes were awarded along the way for funny or efficient solutions to different levels. We stopped after 2 hours with no team managing to finish the game –although coming really close to the end and even stopping on the last level- but with all teams doing much better than Dr. Rice.