Recent blog entries for crhodes

lots of jobs in computing at goldsmiths

There’s an awkward truth that perhaps isn’t as well known as it ought to be about academic careers: an oversupply of qualified, motivated candidates chasing an extremely limited supply of academic jobs. Simplifying somewhat, the problem is: if one tenured professor (or “lecturer” as we call them in the UK) is primarily responsible for fifteen PhDs over their career, then fourteen of those newly-minted doctors will not get permanent jobs in academia.

That wouldn’t be a problem if the career aspirations of people studying for doctorates were in line with the statistics – if about one in ten to one in twenty PhD candidates wanted a job in academia, then there would be minimal disappointment. However, that isn’t the case; many more doctoral students have the ambition and indeed the belief to go on and have an academic career: and when belief meets reality, sometimes things break. Even when they don’t, the oversupply of idealistic, qualified and motivated candidates leads to distortions, such as a large number of underpaid sessional teaching staff, assisting in the delivery of courses to ever larger cohorts of students (see also). The sector hasn’t sunk as low as the “unpaid internship” seen in other oversupplied careers (games, journalism, fashion) – though it has come close, and there are some zero-hour contract horror stories out there, as well as the nigh-on-exploitative short-term postdocs that are also part of the pyramid.

All this is a somewhat depressing way to set the scene for our way of redressing the balance: Goldsmiths Computing is hiring to fill a number of positions. Some of the positions are traditional lecturer jobs – fixed-term and permanent – and while they’re good openings, and I look forward to meeting candidates and working with whoever is successful, they’re not what’s most interesting here. We have also allocated funds for a number of post-doctoral teaching and research fellowships: three year posts where, in exchange for helping out with our teaching, the fellows will be able to pursue their own research agenda, working in collaboration with (but not under the direction of) established members of staff. I think this is a hugely positive move, and a real opportunity for anyone interesting in the particular kinds of areas of Computing that we have strengths in at Goldsmiths: Games and Graphics, Music and Art Computing, Data and Social Computing, Human-Computer Interaction and AI, Robotics and Cognition. (And if applicants were to want to work with me on projects in Music Informatics or even involving some programming language work, so much the better!)

The complete list of positions we’re hoping to fill (apply by searching for the “Computing” Department in this search form) is:

  • Lecturer in Computational Art – 0.5FTE, 3 year fixed-term
  • Lecturer in Computer Science – full-time, 3 year fixed-term
  • Lecturer in Computer Science – 0.5FTE, 3 year fixed-term
  • Lecturer in Games and Graphics – full-time, open-ended
  • Lecturer in Games Art – 0.5FTE, open-ended
  • Lecturer in Physical Computing – full-time, open-ended
  • Post-doctoral Teaching and Research Fellow – full-time, 3 year fixed-term

The deadline for applications for most of these posts is Monday 8th June, so get applying!

Syndicated 2015-06-01 09:27:02 from notes

els2015 it happened

Oh boy.

It turns out that organizing a conference is a lot of work. Who’d have thought? And it’s a lot of work even after accounting for the benefits of an institutional Conference Services division, who managed things that only crossed my mind very late: signage, extra supplies for college catering outlets – the kinds of things that are almost unnoticeable if they’re present, but whose absence would cause real problems. Thanks to Julian Padget, who ran the programme, and Didier Verna, who handled backend-financials and the website; but even after all that there were still a good number of things I didn’t manage to delegate – visa invitation letters, requests for sponsorship, printing proceedings, attempting to find a last-minute solution for recording talks after being reminded of it on the Internet somewhere... I’m sure there is more (e.g. overly-restrictive campus WiFi, blocking outbound ssh and TLS-enabled IMAP) but it’s beginning to fade into a bit of a blur. (An enormous “thank you” to Richard Lewis for stepping in to handle recording the talks as best he could at very short notice).

And the badges! People said nice things about the badges on twitter, but... I used largely the same code for the ILC held in Cambridge in 2007, and the comment passed back to me then was that while the badges were clearly going to become collectors’ items, they failed in the primary purpose of a badge at a technical conference, which is to give to the introvert with poor facial recognition some kind of clue who they are talking to: the font size for the name was too small. Inevitably, I got round to doing the badges at the last minute, and between finding the code to generate PDFs of badges (I’d lost my local copy, but the Internet had one), finding a supplier for double-sided sheets of 10 85x54mm business cards, and fighting with the office printer (which insisted it had run out of toner) the thought of modifying the code beyond the strictly necessary didn’t cross my mind. Since I asked for feedback in the closing session, it was completely fair for a couple of delegates to say that the badges could have been better in this respect, so in partial mitigation I offer a slightly cleaned-up and adjusted version of the badge code with the same basic design but larger names: here you go (sample output). (Another obvious improvement suggested to me at dinner on Tuesday: print a list of delegate names and affiliations and pin it up on a wall somewhere).

My experience of the conference is likely to be atypical – being the responsible adult, I did have to stay awake at all times, and do some of the necessary behind-the-scenes stuff while the event was going on. But I did get to participate; I listened to most of most of the talks, with particular highlights for me being Breanndán Ó Nualláin’s talk about a DSL for graph algorithms, Martin Cracauer’s dense and technical discussion of conservative garbage collection, and the demo session on Tuesday afternoon: three distinct demos in three different areas, each both well-delivered and with exciting content. Those highlights were merely the stand-out moments for me; the rest of the programme was pretty good, too, and it looked like there were some good conversations happening in the breaks, over lunch, and at the banquet on Monday evening. We ended up with 90 registrations all told, with people travelling in from 18 other countries; the delegate with the shortest distance to travel lived 500m from Goldsmiths; the furthest came from 9500km away.

The proceedings are now available for free download from the conference website; some speakers have begun putting up their talk materials, and in the next few weeks we’ll try to collect as much of that as we can, along with getting release permissions from the speakers to edit and publish the video recordings. At some point there will be a financial reckoning, too; Goldsmiths has delivered a number of services on trust, while ELSAA has collected registration fees in order to pay for those services – one of my next actions is to figure out the bureaucracy to enable these two organizations to talk to each other. Of course, Goldsmiths charges in pounds, while ELSAA collected fees in euros, and there’s also the small matter of cross-border sales tax to wrap my head around... it’s exciting being a currency speculator!

In summary, things went well – at least judging by the things people said to my face. I’m not quite going to say “A+ would organize again”, because it is a lot of work – but organizing it once is fine, and a price worth paying to help sustain and to contribute to the communication between multiple different Lisp communities. It would be nice to do some Lisp programming myself some day: some of the stuff that you can do with it is apparently quite neat!

Syndicated 2015-04-23 10:47:10 from notes

20 Mar 2015 (updated 20 Mar 2015 at 18:13 UTC) »

els2015 is nearly here

This year, I have had the dubious pleasure of being the Local Organizer for the European Lisp Symposium 2015, which is now exactly one month away; in 31 days, hordes of people will be descending on South East London New Cross Gate to listen to presentations, give lightning talks and engage in general discussions about all things Lisp – the programme isn’t quite finalized, but expect Racket, Clojure, elisp and Common Lisp to be represented, as well as more... minority interests, such as C++.

Registration is open! In fact, for the next nine days (until 29th March) the registration fee is set at the absurdly low price of €120 (€60 for students) for two days of talks, tutorials, demos, coffee, pastries, biscuits, convivial discussion and a conference dinner. I look forward to welcoming old and new friends alike to Goldsmiths.

Syndicated 2015-03-20 17:04:33 (Updated 2015-03-20 17:32:13) from notes

tmus research programmer position

The AHRC-funded research project that I am a part of, Transforming Musicology, is recruiting a developer for a short-term contract, primarily to work with me on database systems for multimedia (primarily audio) content. The goal for that primary part of the contract is to take some existing work on audio feature extraction and probabilistic nearest-neighbour search indexing, and to develop a means for specialist users (e.g. musicologists, librarians, archivists, musicians) to access the functionality without needing to be experts in the database domain. This of course will involve thinking about user interfaces, but also about distributed computation, separation of data and query location, and so on.

The funding is for six months of programmer time. I would have no objection to someone working for six months in a concentrated block of time; I would also have no objection to stretching the funding out over a longer period of calendar time: it might well provide more time for reflection and a better outcome in the end. I would expect the development activities to be exploratory as well as derived from a specification; to span between the systems and the interface layer; to be somewhat polyglot (we have a C++ library, bindings in Python, Common Lisp and Haskell, and prototype Javascript and Emacs front-ends – no applicant is required to be fluent in all of these!)

There are some potentially fun opportunities during the course of the contract, not least working with the rest of the Transforming Musicology team. The post is based at Goldsmiths, and locally we have some people working on Systems for Early Music, on Musicology and Social Networking, and on Musical Memory; the Goldsmiths contribution is part of a wider effort, with partners based at Oxford working on Wagnerian Leitmotif and on a Semantic Infrastructure, at Queen Mary working on mid-level representations of music, and in Lancaster coordinating multiple smaller projects. As well as these opportunities for collaboration, there are a number of events coming up: firstly, the team would hope to have a significant presence at the conference of the International Society for Music Information Retrieval, which will be held in Málaga in October. We don’t yet know what we will be submitting there (let alone what will be accepted!) but there should be an opportunity to travel there, all being well. In July we’ll be participating in the Digital Humanities at Oxford Summer School, leading a week-long programme of workshops and lectures on digital methods for musicology. Also, in November of 2014, we also participated in the AHRC’s “Being Human” festival, with a crazy effort to monitor participants’ physiological responses to Wagner opera; there’s every possibility that we will be invited to contribute to a similar event this year. And there are other, similar projects in London with whom we have friendly relations, not least the Digital Music Lab project at City University and the EU-funded PRAISE project at Goldsmiths.

Sound interesting? Want to apply? There’s a more formal job advert on the project site, while the “person specification” and other application-related materials is with Goldsmiths HR. The closing date for applications is the 27th March; we’d hope to interview shortly after that, and to have the developer working with us from some time in May or June. Please apply!

Syndicated 2015-03-16 11:47:14 from notes

ref2014 data update

Does anyone still care about REF2014? Apart from agonizing about what it will mean in the new assignments of quality-related funding for institutions, obviously.

Among the various surprising things I have had to do this term (as in “surprise! You have to do this”) was to participate in the Winter graduation ceremony: reading out the names of graduands. It was fun; the tiniest bit stressful, because I hadn’t ever managed to attend a ceremony – but since everyone was there to celebrate, most of the pressure was off; I think I managed to doff my hat at the required times and not to trip over my gown while processing. Part of the ceremony is a valedictory speech from the Warden (vice-Chancellor equivalent), and it was perhaps inevitable that part of that was a section congratulating our soon-to-be alumni on belonging to an institution with high-quality research, or possibly “research intensity”.

That reminded me to take another look at the contextual data published by the Higher Education Statistics Authority; part of the “research intensity” calculation involves an estimate of the number of staff who were eligible to participate in the REF. It is only an estimate, not for any fundamental reason but because the employment data and the research submissions were collected by two different agencies; the data quality is not great, resulting probably in about equal measure from database schema mismatches (working out which REF2014 “Unit of Assessment” a given member of departmental staff belongs to) and human error. The good news is that at least the human error can be corrected later; there are now four Universities who have submitted corrected employment numbers to HESA, subtracting off a large number of research assistants (fixed-term contract researchers) from their list of REF-eligible staff – which naturally tends to bump up their measured research intensity.

New corrections mean new spreadsheets, new slightly-different data layouts, and new ingestion code; I suffer so you don’t have to. I’ve made a new version of my ref2014 R package containing the REF2014 results and contextual data; I’ve also put the source of the package up on github in case anyone wants to criticize (or learn from, I guess) my packaging.

Syndicated 2015-03-10 13:36:30 from notes

a year in review

A brief retrospective, partly brought to you by grep:

  • CATS credits earnt: 30 (15 + 7.5 + 7.5) at level 7
  • crosswords solved: >=40
  • words blogged: 75k
  • words blogged, excluding crosswords: 50k
  • SBCL releases made: 12 (latest today!)
  • functioning ARM boards sitting on my desk: 3 (number doing anything actually useful, beyond SBCL builds: 0 so far, working on it)
  • emacs packages worked on: 2 (iplayer squeeze)
  • public engagement events co-organized: 1
  • ontological inconsistencies resolved: 1
  • R packages made: 1 (University PR departments offended: not enough)

Blogging’s been a broad success; slightly tailed off of late, what with

  • Crawl Dungeon Sprint wins: 2 (The Pits, Thunderdome: both GrFi)

so there’s an obvious New Year’s Resolution right there.

Happy New Year!

Syndicated 2014-12-31 22:27:37 from notes

ref2014 data in R package form

As threatened, one last post about REF2014. Actually this post is not so much about REF2014 any more; it’s mostly about R. I’ve finally found the time to package up the REF2014 data as a convenient R package, along with accompanying documentation and a “vignette”. Some quick observations about the process:

  • it’s not desperately easy to find authoritative documentation on best practices, or even appropriate first steps. There’s authoritative documentation on the format and contents of an R package, but that documentation suffers from describing what not to do without describing what to do instead (example); there’s Hadley Wickham’s suggestions for best practices, but not quite enough of those suggestions were applicable to this case (data-only, converted from upstream formats). Putting it all together took more brain cycles than I care to admit.

  • Sweave is a bit clunky. It does the job but I can’t help but compare it to org-mode and markdown (R has knitr for markdown vignettes, but I couldn’t get rmarkdown working in the budgeted time, so fell back to Sweave).

  • it’s quite nice to be forced to document all the columns of a data frame. I say “forced”; it’s not that strong, but having R CMD check tell me about all the bad things I’ve done is a decent motivator.

I’m not sure what the licence of the REF2014 data is (or even if that is a question that makes sense). It appears I’m not the only one who is unsure; the Web and Internet Science crowd at Southampton have put up a RDF version of the REF2014 data, and Christopher Gutteridge doesn’t know about licensing either. Meanwhile, in the general belief that having this dataset more available is likely to be positive, all things considered, have at it (and tell me where the packaging has gone wrong...).

Syndicated 2014-12-28 22:44:45 (Updated 2014-12-28 22:55:18) from notes

research excellence framework more ranks to choose from

Apparently the Pro-Warden of Research and Enterprise at my institution discovered the ‘GPA intensity’ measure for ranking Universities: or at least saw fit this morning to circulate to all staff a message saying

This league table both confirms and affirms Goldsmiths as a research-intensive university within an inclusive research culture – something we can all be proud of.

which is at least sort-of true – as I suggested last night, I think an intensity measure is just about on the side of the angels. One flaw in the REF process is the element of choice in who to submit, though there are problems in just disallowing that choice, including the coercion of staff onto teaching-only contracts; maybe the right answer is to count all employees of Universities, and not distinguish between research-active and teaching-only (or indeed between academic and administrator): that at least would give a visibility of the actual density (no sniggering at the back, please) of research in an institution.

As should be obvious from yesterday’s post, I don’t think that the league table generated by GPA intensity, or indeed the league table by unweighted GPA, or indeed any other league table has the power to confirm anything in particular. I think it’s generally true that Goldsmiths is an institution where a lot of research goes on, and also that it has a generally open and inclusive culture: certainly I have neither experienced nor heard anything like the nastiness at Queen Mary, let alone the tragedy of Stefan Grimm at Imperial. But I don’t like the thoughtless use of data to support even narratives that I might personally believe, so let’s challenge the idea that GPA intensity rank is a meaningful measure.

What does GPA intensity actually mean? It means the GPA that would have been achieved by the institution if all eligible staff were submitted to the REF, rather than just those who actually were, and that all the staff who weren’t originally submitted received “unclassified” (i.e. 0*) assessments for all their contributions. That’s probably a bit too strong an interpretation; it’s easy to see how institutions would prefer not to submit staff with lower-scoring outputs, even if their scoring would be highly unlikely to be 0*, whether they are optimizing for league tables or QR funding. So intensity-corrected GPA probably overestimates the “rank” of institutions whose strategy was biased towards submitting a higher proportion of their staff (and conversely underestimates the “rank” of institutions whose strategy was to submit fewer of their staff).

It probably is fair to guess, though, that the unsubmitted staff don’t have many 4* “world leading” outputs (whatever that means), honourable exceptions aside. So the correction for intensity to compare institutions by percentages of outputs assessed as 4* is probably reasonable. Here it is:

4* outputs with/without intensity

Another case where an intensity correction is probably reasonable is when comparing institutions by some combination of their 4* and 3* scores overall (i.e. including Impact and Environment): this time, because the 4* and (probably to a lesser extent) 3* scores will probably be one of the inputs to QR funding (if that carries on at all), and the intensity correction will scale the funding from a per-submitted-capita to a per-eligible-capita basis: it will measure the average QR funding received per member of staff. As I say, we don’t know about QR funding in the future; using the current weighting (3×4*+1×3*), the picture looks like this:

4*/3* 3:1 overall with/without intensity

But wait, does it make sense to rank these at all? Surely what matters here is some kind of absolute scale: small differences between per-capita QR funding at different institutions will be hardly noticeable, and even moderate ones are unlikely to be game-changers. (Of course, institutions may choose not to distribute any QR funding they receive evenly; such institutions could be regarded as having a less inclusive research culture...). So, if instead of plotting QR ranks, we plot absolute values of the QR-related “score”, what does the picture look like?

4*/3* 3:1 overall values with/without intensity

This picture might be reassuringly familiar to the UK-based research academic: there’s a reasonable clump of the names that one might expect to be characterized as “research-intensive” institutions, between around 89 and 122 on the right-hand (intensity-corrected) scale; some are above that clump (the “winners”: UCL, Cambridge, Kings London) and some a bit below (SOAS). Of course, since the members of that clump are broadly predictable just from reputation, one might ask whether the immense cost of the REF process delivers any particular benefit. (One might ask. It’s not clear that one would ever get an answer).

I should stop playing with slopegraphs and resume work on packaging up the data so that other people can also write about REF2014 instead of enjoying their “holidays”.

Syndicated 2014-12-23 15:13:49 from notes

research excellence framework and public relations

Last week saw the publication of the results of the “Research Excellence Framework” – a title which does almost nothing to describe what it actually is. To those reading not from academia, or from those portions of academia where this monstrosity has not penetrated, the REF involved university departments gathering sets of up to four publications from a subset of their research-active staff who were employed by them on 1st December 2013; writing submission documents to explain why those publications should be considered world-leading or at least internationally excellent; gathering and documenting “Impact” case studies, and writing about the general environment for performing research. These submissions then went to assessment panels, who did some unknowable things with them before producing assessments of the submissions: for each of the three measures (outputs, impact and environment), the percentages of that submission judged to be at particular levels, measured from 4* (world-leading) down to 0* (unclassified), and these assessments will affect in some as yet undetermined way Quality-Related funding for Higher Education Institutions (if QR funding continues at all). Those data are now published, along with, for each department, the count of full-time-equivalent research staff considered as part of the submission, and (inexplicably, about eight hours later) figures from a different higher-education agency estimating the number of staff who would have been eligible to be considered as part of each submission.

If your first reaction to all of this is “wow, that’s a well-thought-through system that will in no way become subject to Goodheart’s law”, well, I envy you your worldview. Gaming the REF starts early: since it is the employment status on 1st December 2013 that matters for the purpose of this exercise, rather than the location at which any given piece of research was done (or the address for correspondence given on the published research), economic forces quite naturally set up a transfer window, where researchers likely to score highly in the REF if included in a submission are able to name high prices for moving in the six months leading up to the census date – and there’s then much less flexibility in the academic labour market for a good year or two afterwards. Other employment distortions happen too; for example, there’s an incentive to approach researchers based outside the UK, and offer to pay them a fractional wage (say 0.2FTE) in exchange for them offering up four of their publications, assumed to be high-scoring, for submission to the UK REF. Given the way the QR funding is distributed, this is in effect a subsidy to departments with well-connected heads, and to already-successful overseas researchers.

But aside from the distortions that arise from producing the submissions, and the simultaneously unclear and opaque way that judgment on those submissions is made, at least the result of all of this is a table of numbers, which don’t lie, right? Right.


I happened to be in a different country on REF results day, doing different work. So my main view of what was going on was following the #REF2014 twitter stream. And maybe I envy myself my previous worldview, because I was not prepared for the deluge of mendaciousness. I don’t know what I was expecting – a discussion between academics, maybe, or a quick dissection of the figures, and some links to news articles and blog posts. What I actually got was corporate account after account claiming victory in the REF, using various ways of weighting and ordering the measures. Particularly egregious examples included:

  • failing to distinguish between case studies and overall research, typically seen in “x% of our research has world-class impact” or similar: @unisouthampton @cardiffphilos @ITSLeeds @UWEGradSchool @LancasterManage

  • talking about “research power”, which multiplies a GPA-type score by the FTE quantity of staff submitted to the assessment. By introducing this, larger institutions can successfully confound a notional measure of quality with a measure of quantity to produce something essentially meaningless (except that it will likely be some similar formula which determines QR funding – but most University costs are per-capita costs anyway, so this still doesn’t make much sense): @LawLeicester @CityUniHealth @UniofReading @EconomicsatYork @UoNresearch @ScienceLeeds

  • simple gibberish: @CovUniResearch, and the Guardian gets a special prize for attempting to use the REF to compare apples to oranges.

It was also disappointing to see corporate twitter accounts attempting to find measures to optimize their ranking positions after the fact; John O’Leary has observed that at least four institutions have claimed overall “victory”, as if one institution’s research could defeat another’s. As well as overall victory, though, a seemingly-infinite number of departmental accounts claimed victory, or a top-ten position, or a top-twenty (or 16th, or 22nd, or 66th) as if that was meaningful. Do we really believe that the panels, in all their wisdom, can assess the difference between “internationally excellent” and “world-leading” to a sufficient accuracy that differences in GPA scores in the third significant place are meaningful? In other words, where are the error bars on these measurements?

To finish up: I spent too long today downloading the HEFCE and HESA data, cleaning it up, swearing at UCL’s acquisition of the Institute of Education, and messing around with ggplot. I hope to publish the cleaned-up data files for others to play with in the holidays; in the meantime, I leave you with this illustration of the game-playing: since there are multiple outcomes from one set of REF measurements, different institutions will have used different strategies for choosing which of their staff to submit and which not: to attempt to optimize their Grade Point Average, their (hoped-for) QR funding, or their likelihood of a good headline on 18th December 2014. We can measure some of that by looking at the difference between GPA scores, and GPA scores scaled by the proportion of eligible staff who were actually submitted. To illustrate that, I’ve made a Tufte-style slopegraph; the only concession to modernity is that the steeper the slope, the darker the ink of the line. (Modernity in character encoding – sorry, Glyndŵr University – and font-antialiasing is completely unaddressed).

GPA with/without intensity

You can decide whether either of the GPA measures is more or less meaningful; I have no particular axe to grind (though I suspect that my institution might, and on balance I think they are on the side of the angels who know how to dance slightly better on the head of a pin). One message this graph tells that everyone should be able to agree on is that it illustrates different strategies being employed – if there were uniformity across the sector, the lines would be generally horizontal. (And the real tragedy of all this is that clever, dedicated people at institutions of research and learning spent actual time and energy thinking about REF submission strategies, instead of doing something interesting and potentially useful).

In some sense, I hope not to come back to this subject. But it’s the holidays, and I need something that seems enough like work avoidance that it will distract me from preparing my lectures for next term...

Syndicated 2014-12-22 23:14:03 (Updated 2014-12-22 23:17:31) from notes

17 Nov 2014 (updated 17 Nov 2014 at 13:14 UTC) »

hearing wagner data preparations

Last week’s activity – in between the paperwork, the teaching, the paperwork, the paperwork, the teaching and the paperwork – was mostly taken up in preparations for the Hearing Wagner event, part of the AHRC’s Being Human festival.

Being a part of the Being Human festival gave us the opportunity to work to collect data that we wouldn’t otherwise have had access to: because of the fortuitous timing of the Mariinsky Theatre’s production of the Ring at the Birmingham Hippodrome between 5th and 9th November, we were able to convince funders to allow us to offer free tickets to Birmingham Conservatoire students, in exchange for being wired up to equipment measuring their electrodermal activity, blood flow, and hand motion.

Why collect these data? Well, on of the themes of the Transforming Musicology project as a whole is to examine the perception of leitmotive, particularly Wagner’s use of them in the Ring, and the idea behind gathering these data is to have ecologically-valid (in as much as that is possible when there’s a device strapped to you) measurements of participants’ physical responses to the performance, where those physical responses are believed to correlate with emotional arousal. Using those measurements, we can then go looking for signals of responses to leitmotives, or to other musical or production cues: as well as the students attending the performance, some of the research team were present backstage, noting down the times of events in the staging of (subjective) particular significance – lighting changes, for example.

And then all of these data come back to base, and we have to go through the process of looking for signal. And before we can do anything else, we have to make sure that all of our data are aligned to a reference timeline. For each of the operas, we ended up with around 2GB of data files: up to 10 sets of data from the individual participants, sampled at 120Hz or so; times of page turns in the vocal score, noted by a musicologist member of the research team (a coarse approximation to the sound experienced by the participants); timestamped performance annotations, generated by a second musicologist and dramaturge. How to get all of this onto a common timeline?

Well, in the best of all possible worlds, all of the clocks in the system would have been synchronized by ntp, and that synchronization would have been stable and constant throughout the process. In this case, the Panglossians would have been disappointed: in fact none of the various devices was sufficiently stably synchronized with any of the others to be able to get away with no alignment.

Fortunately, the experimental design was carried out by people with a healthy amount of paranoia: the participants were twice asked to clap in unison: once in the backstage area, where there was only speed-of-sound latency to the listeners (effectively negligible), and once when seated in the auditorium, where there was additional latency from the audio feed from the auditorium to backstage. Those claps gave us enough information, on the rather strong assumption that they were actually simultaneous, to tie everything together: the first clap could be found on each individual measuring device by looking at the accelerometer data for the signature, which establishes a common timeline for the measurement data and the musicologists; the second clap gives a measure for the additional latency introduced by the audio feed. Since the participants’ claps weren’t actually simultaneous – despite the participants being music students, and the clap being conducted – we have a small error, but it’s likely to be no more than about one second.

And this week? This week we’ll actually be looking for interesting signal; there’s reason to believe that electrodermal activity (basically, the change in skin conductance due to sweat) is indicative of emotional arousal, and quite a sensitive measure of music-induced emotion. This is by its nature an exploratory study: at least to start with, we’re looking at particular points of interest (specified by musicologists, in advance) for any correlation with biosignal response – and we’ll be presenting initial results about anything we find at the Hearing Wagner event in Birmingham this weekend. The clock is ticking...

edit: see also a similar post on the project blog

Syndicated 2014-11-17 10:58:17 (Updated 2014-11-17 12:49:11) from notes

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