Friday, April 24, 2009

gay bars at 11am

today I was interviewd by some BBC folks from the Culture Show, about copyright and the internet, in a gay bar (The Friendly Society) behind a sex shop (Ann Summers) in SoHo, london

this was an unnerving experience - all the strip joints in the alley way were just starting to open - it was a glorious sunny day at 11am

Frrrankly, it made a change:)

(What did I say? well you'll have to wait and see:)

meanwhile, Derek Murray continues to update his
Exemplary NSDI Live Blog - this should be a lesson in how to take notes at a conference!

Thursday, April 23, 2009


so i've come across this category of complexity a couple of times, and finally got around to reading it up (page 155 of Garey & Johnson"Computers and Intractability, if you must:-)

its a slightly refined way of looking at a sub class (but a large sub class) at the "harder" end of NP- - basically, instead of just decidability, a Non Deterministic Counting Turing Machine (TM:-) tells you "how many". (hence the #)

so in problems like maximal matching pairs on a bi-partite graph (e.g. call assignment problem in circuit switched net, or route/scedule problem in multihop radio) which can be "reduced" to a set packing problem (and knowing how many makes it a #P equiv to set packing)

Computational Complexity of Loss Networks

Monday, April 20, 2009

debugging in every day life

this easter I had a mixed time debugging things - aside from family (basically a DDoS attack on the fridge&larder from Ireland and France), various things (i.e. stuff) went wrong in interesting (or dull) ways

first, the fridge decided to turn everything to Ice - this turned out to be quite simple - someone had piled Easter Eggs on top of it pushed all the way back to the wall, so the heat exchanger pushing heat out was having to work overtime and the calibration presumably went awry - removing soggy easter eggs from top and putting them in the freezer to reform made that problem go away

second, the very nice, cheap and elegant and easy to use Humax PVR decided to do a few weird recording errors - we'd seen this first when the clocks went forward for "British Summer Time - but I hadn't bothered looking up the full glory that is Digital Broadcast and Electronic Programme Guides (EPG) - this time, we had a couple of truncated recordings and one that overran by 2 hours - so it turns out (thanks to the extremely well documented "hummy" web site and various AV consumer advice sites) that this is largely due to bugs in different implementations of the EPG combined with occasional missing or mis-broadcast EIT (end indication time) signals inband which tell the PVR when a program "really" ends (as opposed to the time set in advance which may not be right any more) .... plus some really strange effects if your multiple tuner PVR decides to use several different broadcast sources (which the Humax 9200T can do apparently - awesome)....anyhow, the overrun problem isn't really a problem but the truncastion is a bit of a pain, so I fiddled around according to various pieces of guidance and may or may not have fixed it...

third, one of the Macs in the house has been deciding that the wireless net isn't there periodically, and has to be told to pick it again (even though it is the ONLY preferred network...) - 4 other Macs in the house all work fine - this turns out to be a WPA re-authentication timer bug in the intel core solo Mac Mini 802.11 security thing - since apple have known this for dokeys years and it ought to just be driver stuff, I really don't know why it isn't fixed- only workaround for now is to go to WEP only security which I don't really care much about coz we only do ssh/ssl any how so there's no real harm, but it is a bit silly (early MacOS was ok, and later is ok - just ones around 10.4.10/10.4.11...i suppose i can roll back or upgrade ....what a palaver)

oh then there was an intermittent audio problem on the playstation 3 on the new LG HD TV - basically it looks like there's an HDMI audio incompatibility (that turned out to be easy - PS3 helpsites abound and advise on how to pick the most liely to work audio codec)...

then there was trying to get 11 and 16 year old to do maths homework/revision (for SATS and GCSEs respectively) - in retrospect, the techie stuff was trivial in comparison

Friday, April 17, 2009

mashing up state of mind and different web page layout

so I am sitting in a programme committee meeting using Eddie Kohler's excellent Hotcrp conference management software - this is used for writing reviews, putting in comments to other PC members and writign discussion notes between PC members during the processs - but it occurs to me that I am blogging it using the same form entry stuff in, and I am posting stuff in facebook using a similar form and in facebook status updates in a similar form - these are all completely different activities yet if one comes to one activity from another, one might mix up the kind of frame of mind one shoudl be in - for example, people posting status update on facebook are very similar in their approach to people tweeting on twitter (lots of bitchin - a bit like youtube comments:) whereas reviewing a paper is a serious activity giving rational for a score/rank and communicating feedbakc to authors (maybe to fix the paper if accepted, or to improve for submissio nelsewhere - and comments to the PC or discussion notes to other PC members are not for publication, but also should be considered at least, rather than subjective/emotive/assertive...

so how would one provide the right "illocutionary act" mindset to an input form (and its display once edit is finished) graphically? fonts, colours, what?

Wednesday, April 15, 2009

.towards the economics of information

today's idea/conjecture

there's an economics of information density and this is why twitter is gibberish and
blogs with google ads makes sense

basically, its some sort of entropic/SNR thing which is to do with the percentage of cognition someone is prepared to spend on stuff that isn't 100% germane (fancy word for relevant)

i think there's two pieces
1. there's a minimum unit's worth which is about 1 web page (8kbytes) - below this (think twitter or SMS), there's no useful semantic content, and its pure deontic/emoticon stuff - above this, the brain can afford some idling time to eyeball some stuff around the edges

so if you can't make money purely from the service (think sms/twitter) for low payload things you are doomed, but once you get into the page (think pagerank) you can build parasitic ways of making money (like advertising) in those cases, you want the _service_ to be free to maximise your chances of reaching the right people with the advert....(the advert could itself just be links to more content of course)

incidentally, this is why the IP MTU should have been 8Kbytes, not 576 (or the de facto 1500) it is today...

Monday, April 13, 2009

Computational thinking

so there's a school of thought that we need to get "commputational thinking" into the early school curriculum - on the other hand, I detect signs that quite a few building blocks of computational style thought are already part of the everyday mindscape - the notional of irony, post-modernism, and narrative tricks like the reverse memory plot in memento, or time travel paradoxes in Dr Who (or easter egg hacks in the famous Blink episode) do not cause the public to go "errrr, wot?" - they are all just part of the norm refs for kids and so i suspect it will be found quite easy (provided one does'nt do something horribly heavyhanded) to capture this in a small number of concepts that can be embedded in lots of other subjects...

on the other hand, everyone should learn to program at the same time as reading, writing and rythmetic and music.

Thursday, April 09, 2009

Bogo cod HCI

I hate those emails from myspace and facebook that purport to be from a person
("from the facebook team")

can't they just say
from the Oort Cloud
from your friendly neighbourhood bot
or something truthful?

Tuesday, April 07, 2009

why havn't we got one of these hackerspace things...

in cambridge?
or do we?

odd types of computer

the occasionally awesome James May on TV this week explained semi-conductors by olding up a spoon (conductor) and a copy of a vinyl record in cardboard record cover of Jeff Wayne's Musical Version of The War of the Worlds (insulator)

this made me think of alternative crazy types of gate that one might propose

historical battles (marathon, poitiers 1&2 etc) aer really gating functions to either populations or cultures moving from one area to another - think of the movement as a large current, and the small armies (relatively speaking ) as a voltage applied - i.e. valve/transistor/switch/gate...

so the whole of history of human migration and population plus landmark battles could be viewed as a computation....what does it compute tho? 42? 23? or does it just deliver a ring pull from a coke can to a stranded tralfamadorian on Titan?

Monday, April 06, 2009

flocking copters...

so i was proposing flocking copters made from commodity (e.g. hobby copters for a 100 quid) - that was 2001 - now we see
cube warriors and war porn is reality.