Wednesday, May 13, 2015

Erlang MOOC pilot, day 3

We’re at day 3 of our MOOC pilot on functional programming in Erlang: so how are things going?

MOOCs aren’t synchronous, and so people can begin and progress in their own time. So far half of those who signed up in advance have started to use the MOOC, and half of them have progressed a good way through the first week’s material. We have people taking an active part from (in no particular order) the Netherlands, Spain, Russia, the USA, Mexico, Denmark, Italy, France, Argentina, Chile, Japan, the Czech republic, New Zealand, China, Canada, the UK amongst others.

We’re also finding our way in working out the best ways of interacting. Our forums are split “by activity” and while this keeps each one on topic, it leaves no space for general discussions, so we’ve added a “common room” for those discussions. We also wanted to share with everyone some of the responses to points being made in the feedback form, so we have added a (growing) FAQ page to hold those questions and answers. Luckily we’re able to sort quite a few things out, but some others – like making videos downloadable – are going to take more time, and internal university discussions, to resolve.

We’re also beginning to see discussion and feedback on programming homework assignments. Part of the MOOC ethos is to involve everyone in giving feedback about others’ work and problems, so we have a fully meshed network rather than spoke to hub with the Kent staff providing feedback and so on. It’s still early days, but discussions are beginning. We also had a request for acceptance tests for the homeworks, but again for the purposes of the trial we’re encouraging participants themselves to develop and share these too. We might come back to this as the pilot progresses …

So far Moodle seems to be coping … there would be clear advantages to going with a fully-featured MOOC platform, such as providing transcripts of the videos for accessibility reasons, but Moodle seems to be managing so far. We’re also able to see how people are progressing in quite some detail, so there will be number crunching going on over the course of the pilot, and hopefully some useful data analysis as an outcome.

Monday, coincidentally, we were part of a tea party to celebrate the Beacon Projects at Kent, and as part of that we got a lot of encouragement and interest in what we’re doing. It can only help with developing a case to argue to the university about the multi-faceted value of MOOCs, online lectures and blended learning to our staff, students and public reach.

Monday, May 11, 2015

“Functional Programming in Erlang” MOOC pilot

It’s all very peculiar.

We’ve been working flat out to get the pilot MOOC on Functional Programming in Erlang up and running at Kent, we have signed up over 500 participants, and it just went live 20 minutes ago. Rather like sending a book manuscript off to the publishers, it has all gone quiet, and we're waiting to see what's going to happen. I should tell you who the “we” are: apart from me, there’s Mark O'Connor, who is Distance Learning Technologist for the university, and Stephen Adams, who is TA for the course and who is a PhD student in computer science here.

This pilot is part of a bigger plan, which includes supporting our face-to-face teaching of Erlang at Kent, as well as putting out a set of Master Classes in Erlang by Joe Armstrong, one of the inventors of Erlang, Francesco Cesarini, founder of Erlang Solutions Ltd, and me. These will be coming shortly. This K-MOOCs project is being supported by the University of Kent as part of its Beacon Projects initiative, which is in celebration of the University’s fiftieth anniversary.

We recorded the master classes in a studio with green screen etc, to try that out, and these are in the final stages of production, but the majority of the MOOC lectures are more “home made” and were recorded on my MacBook Pro, using the built in audio and video facilities, and Kent’s lecture recording facilities that are powered by Panopto . Given that “available tech” approach, we’ve been pleased with the results (but our participants may choose to differ!).

In getting the MOOC planned and executed, Mark has been tireless in providing infrastructure, in getting me to plan, in editing and in feeding back on all the activities. We’ve also really benefitted from advice and help from Mike McCracken of Georgia Tech, who has pioneered their online CS courses and MOOCs. Without Mike’s advice about how to script the course in advance, implementation would have been so much more difficult.

As it is, we’ve got the course in place. I’ll be adding a few finishing touches – more quizzes! – today, but really we’re waiting to see how people get on with what’s there. I’ll aim to blog some more as the pilot runs, and we see how it all works out.

Thursday, April 30, 2015

Automated Proof in Practice


While it is dangerous to generalise from a single example, it's instructive to look at Foster and Struth's paper as giving us a snapshot of the state of the art in automating ordinary reasoning, but first let’s look at the particular subject of the paper. 

Regular expressions and finite automata are fundamental to the practice of computer science, but they are a fertile topic for research, too. A key question is identity: when do two regular expressions – or two finite automata – behave identically? The answer is “when they describe the same set of strings”, but that's less useful computationally than it first looks, since it requires that we test sets – which potentially are infinite – for equality. So, how else to judge identity? By setting out a collection of laws – or axioms – that encapsulate identity.  Foster and Struth's paper sets out the various attempts, by a number of authors including Boffa, Conway, Kozen and Salomaa, to provide axioms that are sound (don't prove any false negatives) and complete (can prove all identities). 

The “fine structure” of the title is a detailed study of the interrelationships of these sets of axioms: showing when one set implies another – a process of deduction – and when one set is strictly stronger than another, which is shown by giving a counterexample which  meets one set and not the other. The process of both deduction and counterexample-finding are computer assisted, and this provides the main contribution of the paper. 

How does the automation directly contribute to the mathematics? It meant that a number of loose ends could be tidied up: one set of axiomatisations was simplified (though finding hitherto undiscovered relationships between axioms), some missing axioms were found in the statement of a particular axiom set, and a gap was found in an existing, well-known, proof. So, it increased assurance in the work, but probably does not constitute a substantial advance in itself.

On the other hand, the work is indicative of real progress in the facilities available to support online proof and counterexample development. Advances have come in a number of ways. Most important is the way in which different approaches have come together: it used to be that proof was either done “manually” with a proof assistant, or in an entirely automated way using some kind of decision procedure. The work under review uses the Isabelle proof assistant, which now supports the Sledgehammer tool to apply a number of external automated theorem provers for first-order logic, and in cases where this fails, Isabelle has its own simplification and proving systems. This has the effect of allowing users to concentrate their attention on shaping the higher-level architecture of the theories, rather than having to deduce results proof step by (painful) proof step. Where this reaches its limit is when proofs go beyond the purely algebraic and reverie rather more mathematical structure (e.g. sets) as provided by a higher-order logic.

While it's not the case that most mathematicians use theorem proving technology in their day to day practice – as opposed to the wide take-up of computer algebra systems in various areas of maths and engineering – it has taken real hold in the area of mechanised meta-theory of programming languages, as witnessed by the POPLmark challenge http://www.seas.upenn.edu/~plclub/poplmark/. It may well be because this is an area where the scale of proofs can be such that the usual social process of proof checking have been shown to be less than ideal, hence that value that accrues from formalisation, and, in conclusion, it is interesting to speculate on how long it will take for the practising mathematician to reach for a theorem proving system as a part of his or her daily work.

This review of On the Fine-Structure of Regular Algebra by Simon Foster and Georg Struth and published in the Journal of Automated Reasoning is a first draft as submitted to Computing Reviews.

Wednesday, February 25, 2015

Some stories about Alan Turing


So, here are a few Turing stories of my own. The first from Robin Gandy, who supervised by DPhil, and who, in turn, was Turing's PhD student. Robin had a wealth of stories about Turing, many of which made their way into Andrew Hodges' book – Hodges was a postgrad in Oxford with Penrose around the beginning of the 80s. Perhaps most poignant [quoting from Mike Yates' obituary of Robin]  was when asked about Turing's motives if he really did commit suicide, Gandy would become quite heated: “Some things are too deep and private and should not be pried into.” Sara Turing, Alan's mother, certainly always maintained that his death was an accident.

Her biography of Alan was republished in the centenary year by Cambridge University Press, and that also has only remembered stories of his youth and adulthood. The most striking thing for me was the postscript written by his brother John, on their upbringing, which was not untypical for the English upper middle classes in the early years of the century. Two quotes
  • When Alan was two “rightly or wrongly, [my father] decided that he and my mother should return alone to India, leaving both children with foster parents in England” … “it was certainly a shock for me, even at the age of five” but “it was accepted procedure” (and he goes on to compare it with Kipling's horrendous experience, noting that at least they “escaped” that).
  • The real bombshell, though, is schooling. John says, without an ounce of irony or indeed anger “I take credit for persuading my parents to send [Alan] to Sherborne instead of Marlborough, which all but crushed me and would certainly have crushed him”.
A final anecdote. In our previous house, a near neighbour was a retired canon from Canterbury Cathedral, Donald Eperson, who wrote puzzles for the Mathematical Gazette, and who had been a schoolteacher before being ordained. Not any teacher, though, he's taught Alan at Sherborne, and indeed is mentioned in the Hodges biography. He remembered Alan, and I lent him the book – unfortunately, references to his naiveté rather upset him, and I was sorry for unsettling him. 

It's certainly a great thing that Turing has become almost a household name, and that his memory has been rescued for generations to come as one of the greatest scientists of the twentieth century. It's also a great thing that he was pardoned for his conviction for being gay … but surely something that should apply to everyone who was treated so shamefully?

Links

Gandy obituary

Sara Turing bio of Alan

Memoir of Donald Eperson (look for "Music and Mathematics")

The Imitation Game – telling a good story about Alan Turing


So, what to make of The Imitation Game, the film based on the life of Alan Turing?

Well, first of all it tells a good story. Some of the key messages about codebreaking are there:

  • Knowing something about the content – particularly stylised beginnings or endings – make it easier to break the code.  
  • The paradox of the codebreaker: you can't betray that by changing your behaviour too much, or the coders will change their setup … something card players surely recognise.
  • The Bletchley crowd were a mixed bunch: classicists rubbed shoulders with mathematicians and debs.
But it's clearly telling a story in the sense of lying too, and that's a frustration. Maybe it must to move the plot along, but some of the changes seem wilful and so out of character:
  • Part of the extraordinary nature of Bletchley was its scale: in the film it's shrunk to something like a "Famous Five" adventure: Turing and his small crew have the idea for the machine, build it (no Tommy Flowers), and then take the decision about not being able to reveal that the code has been cracked; that just doesn't make historical sense, but I guess keeps the plot moving;
  • An anecdote about the scale of the place: a couple who were in the forces during WW2 were recently visiting Bletchley, and half way round the husband confesses to his wife that he'd worked there during the war – because of the secrecy surrounding the whole operation, he'd been sworn to secrecy – only for her to admit to working there too; perfectly possible
  • More egregious is the sub-plot about Cairncross, and suggesting that Turing had in some way colluded with him – no historical evidence for this at all.
  • Worst of all, I think, was the conceit of Turing's "home computer" Christopher. No evidence for  that at all.
So, it's a good story, well acted and put together, but it tells too many stories to be completely satisfactory. Check out the biography by Andrew Hodges for a comprehensive and erudite view of Turing's life.



Sunday, October 5, 2014

Advice on going to your first conference

I was asked for advice from someone going to his first conference … in this case CodeMesh in London. Here are my thoughts … any comments or other advice?

Strategy … what are you aiming to find out from the conference: some very general impressions about what is going on with functional innovation, something focussed on a particular language or languages, or on particular technologies? Depending on this is …

Plan … CodeMesh has 4 parallel tracks (a real hassle) but it's well worth making sure that you have a plan for what you most want to hear, reflecting your strategy. You should be able to move between individual talks, but that can sometimes be tricky because of synchronisation between different rooms, as well as the distances between rooms. If that's tricky, then you can always change at session breaks.

Another way of choosing is to go to the talk that you know least about. If you go to the one you know most about, that talk will probably spend 80% or more of its time telling you things that you already know. Of course, it needs to be one you're interested in …

Networking … a lot of what happens during the conference is outside the sessions, so do make sure that you make the most of the coffee / tea / meal breaks, and the evening sessions. Speakers are always happy to chat, so you can engage with them outside sessions, or follow up from any questions you ask in a session (scary, but a way of getting noticed). You can always email speakers, introducing yourself, and ask a question, if you do not feel comfortable asking a question after a talk.

Find an introducer, and have them introduce you to some people. If you are going with your PhD supervisor or another colleague or friend who has been there before, they should do the introductions.

Presenting your ideas … you're going to meet people who'll ask what you're working on and you want to interest them and move the conversation along, not stumble over how to explain what you're doing. So, have a 30 second elevator pitch ready.

Talk … OK, you may not feel ready for this, but if you had something specific and interesting to say you can often give a 5 minute "lightning talk" at meetings like CodeMesh. That get you and your work noticed, and people are usually very generous in listening and supporting speakers with less experience.

Learn … if you can get to the tutorials then you can learn a whole lot at these. There are some excellent tutorialists at CodeMesh this year.

Social Media … increasingly there is a whole virtual side to conferences, so track the twitter feed and other online stuff, and contribute yourself too.

Branch out … if you're there with your buddies, don't just stick with them, but aim to meet new people too, particularly at any of the conference social events. Even a casual conversation a couple of times over a couple of conferences lays a foundation for a deeper professional relationship, especially with peers.

Refreshments … there's always free (well, paid for in the registration price) coffee/tea etc. at the breaks and lunch in the middle of the day, but at quite a lot of conferences there's breakfast too, so it's worth getting along in time for that.

Afterwards you can follow up with people you have met by email or social media. You can also catch up on presentations which you missed by watching the video if the conference talks are recorded. Personally, I find that despite my best intentions, it's very unusual for me to find the time to do this.

Particularly for big conferences, it's best to pick and chose which talks to attend rather than sitting in on everything, otherwise you'll get burned out in the first couple of days. “I'd also advise listening to the speakers rather than sitting on your laptop/phone - personally I'd ban such devices from talks!” Also, keep away from alpha male superstars and their groupies … focus on the people who give presentations that fire you with enthusiasm, and those that take your presentation seriously.

Finally, have fun soaking up all the new ideas and meeting all the interesting people behind them.

Updates … thanks to Scott Fritchie, Andy Gill, Kathy Gray, Graham Hutton, Stefan Kahrs, Greg Michaelson, Neil Mitchell and Gem Stapleton for their comments and suggestions.

HTH

Simon

Monday, August 25, 2014

Reading Robert Macfarlane by the internet

There's an old fashioned pleasure to reading on a wet August afternoon. Robert Macfarlane's The Old Ways takes you – in imagination – out into the wilder (or indeed not so wild) parts of Britain. What increases the pleasure and depth of the experience is reading with the internet by your side. With the internet we get so much further …

First, the maps – Ordnance Survey if you have paid for them, or Google maps if not. Walking along the Broomway in (or rather off) Essex takes you to that footpath along the sands, right next to the "DANGER AREA" signs. In the Hebrides, we can find the islands on Google maps – and satellite view - unnamed, but unmistakable from his descriptions. And then to wikipedia to see what gannets look like and read about the peculiar anatomy that sustains their deep dives into  the ocean, making the story of the gannet that pierced the hull of the boat but kept it plugged entirely believable.

And then onto Harris itself. Trying to negotiate the walk he makes – again we have topography and named lakes, but no hill names – but hills cast shadows on the satellite picture, and photographs culled from somewhere (even street view was here) show the picture from the ground. Then we can look at Steve Dilworth's art and read about what Iain Sinclair says about him.

Awe-inspiring.