Posts by tfb
39 posts • joined Monday 11th January 2010 17:11 GMT
Why do it this way?
I know this is trivia, but wouldn't it have been more conventional to wind the company up in the normal way rather than just stop submitting accounts? Perhaps they are above that sort of thing?
Of course if you are using Powerpoint ...
Then almost by definition you are not teaching a hard science or maths, since your notes presumably have little or no mathematical content.
The same goes for printed notes to a great extent: even with the best tool (some TeX variant) creating anything typeset with significant mathematical content is a *lot* of work.
Hand writing maths, on the other hand is very easy since it was designed to be hand-written.
I agree with the make-them-take-notes: as a student I fairly rapidly discovered that just writing stuff down during the lectures (ie taking notes) made a huge difference, even if there were notes handed out (for a hard-science degree if it matters).
It may be that there are people who can get away without this, but I never met any: my suspicion is that you can get away without writing notes in lectures only in easy subjects.
It turns out that there are al sorts of subtleties with this though. One thing that lecturers tend to do is to make use of the fact that both blackboards and whiteboards are mutable: if you have some big complicated equation and you need a slight variant of it, you can rub out various bits and create the variant. But the people taking notes can't do this, and get completely screwed each time you do it, as they have to write the whole thing out again. Later in my course when there were fewer of us and we knew the lecturers better, we would tell them to stop when they did this so we could catch up.
Re: If i upload something that i don't own
The case that's specifically interesting is what happens if I take a picture of someone, which Instagram then use to sell advertising? That's commercial use and I think at least very questionable. Of course it is probably you, not Instagram who are liable for this.
Re: What is there to cherish
A hundred years or so ago infant mortality was about 20% in manufacturing towns in England and women could not vote. Does that make it OK now?
Re: The way to do it...
I suspect the answers to this are "essentially none of them do" and "in the brave new world where people will no longer pay for records, it is essentially their entire income". Connecting these two is left as an exercise.
Re: What is there to cherish
You need to read the original as a critical part was omitted above. I'll put it here: "So here are a few slogans and threats, to make your eyes roll and dismiss another lunatic:". The "occupy" stuff is explicitly taking the piss in other words.
Re: Both
If the speed of sound were infinite then the slinky would be completely rigid: that's what it *means* for the speed of sound to be infinite.
Re: Seems overcomplicated
What tells the top it should start moving is that nothing is now holding it up. The question to ask is: how does each bit of the slinky realise that nothing is now holding it up?
Re: Centre of mass
Information is indeed constrained by the speed of light, or rather: if information can be transmitted faster than c then it is relatively easy to build a time machine, and that's assumed not to be possible.
However as you rightly say, the speed of light has nothing to do with this experiment at all. The information that tells the bottom of the slinky to start moving is transmitted by a longitudinal wave travelling down the slinky, which is essentially travelling at the speed of sound in the slinky, which is remarkably slow. This is, of course, the same for any object: if you drop a vertical metal rod then the bottom will not start falling until the information has reached it, by the same mechanism. In this case you don't see it because the speed of sound in the rod it rather high. You might *hear* it: as the signal is reflected from the end of the rod it may audibly ring.
Re: Seems overcomplicated
The way to understand what is going on is to think about it from the point of view of the bottom of the slinky. Initially it's at rest: when the top of the slinky is released what tells it that it should start moving? The answer is: nothing does, so it stays still, until the signal moving down through the slinky reaches it.
Other cities
As others have mentioned, I think it would be very interesting to see equivalent maps of other cities, and particularly German ones. My mother (who was a child during the war) really won't believe that we gave as good as we got, or in fact much better. I've seen pictures of Frankfurt though, and I'm pretty sure that we did. Of course it may be that they did not record stuff as well, particularly towards the end.
Re: wonder why?
Well, Kennedy's speech about going to the moon was 25 May 1961, and they were on the moon on 21 July 1969, so that's 8 years and a couple of months. So, really, two terms to put someone on the moon. The decision that Apollo 8 should orbit the moon was made in a day, 4 months before the flight. Once upon a time NASA could do astonishing things quickly: could it now, even with the money?
Re: BIG NEWS?
Also, outside of a mind deformed into believing that computers are more important than stuff, who'd care? Why spend a huge amount of money sending a computer whch probably won't work to Mars when you could send the same weight of something with which you can do actual, you know, science?
Re: Where does the heat go?
If you want to run a propulsion system then what you are going to be doing is taking something, making it very hot indeed, and then spitting it out at the highest speed you can manage. That's where the heat goes: into the extremely hot exhaust.
Our favourite thing is: delivery driver leaves a note telling you to collect it from depot. After finding the depot you discover that the driver did not write whatever obscure hundred-digit reference number you need to pick it up on the card. Returning home you discover that the driver has, now, thrown it into the garden, apparently from a great height as most of it now resides in a small crater. You never find all the fragments.
Re: Gotta say
"Firefox's goal is the success of Firefox. Chrome's goal is the success of Chrome. "
I don't think so: Chrome's goal is to help Google sell you advertising.
Two sides to every story
I've been on both sides of this debate, and I have a lot of sympathy with the force-people-onto-managed-systems thing. But unfortinately centrally-managed IT often fails dismally to provide what people need.
At a recent contract, working in, I guess, a development support role, we wanted to build a number of test environments. These would consist of 2-6 VMs for each environment, and perhaps we needed up to 10 environments. We needed to be able to snapshot the VMs so we could test stuff and back it out, but we didn't need backups for instance. So we went to the IT people and asked. The answer came back that a VM cost £4,000, and we couldn't have snapshots because of performance impact. So that would be £8k-£20k per environment, for something which did not meet our requirements. After a lot of fighting we managed to persuade IT that yes, we could have snapshots, but we would have to make a request every time we wanted one, or wanted to revert to one, meaning something that normally took a few seconds would instead take a few hours. This would merely cripple development rather than prevent it altogether.
We could have bought suitable hardware and licenses to support all our environments for the cost of having IT provide one environment which just marginally met our needs.
Re: unbreakable
What no-one ever mentions is that, of course, the Germans were breaking our codes too, and doing so, I think, quite successfully. Indeed, there is at least one case, I think, where a convoy was rerouted based on reading German codes, and the Germans then read the British rerouting instructions and told the U-boats where the convoy would now be.
It's kind of sad that the Wikipedia entry on "B-Dienst" (the German naval codebreaking organisation) is one short paragraph. I mean, they clearly were the bad guys of course, but it would be interesting to get an even slightly unbiased opinion as to what actually went on. Apart from anything else it might help understand how the battle of the Atlantic was actually won, which probably really wasn't the heroic people at Bletchley, but rather a combination between US support and (mostly) the RN and RAF finally pulling their fingers out and talking to each other properly and sorting out air cover that worked (in particular the RAF were obsessed by bombing Germany and just willfully ignoring the "if we don't fix the U-boat problem *right now* we will not be in the war in 6 months" problem, and the RN really didn't get the "you have to defend the convoys, that's all that counts" thing for a long time).
Re: Ah, but...
Indeed, they may have built a device for turning matter into energy. Perhaps a very large, gravitationally-bound fusion reactor which will burn for billions of years.
Re: If we are no alone
"Even if they're not hungry, there's no reason (based on Earth experience) to expect technological advancement to correlate with peaceful and benevolent behaviour.".
Actually, there are lots of reasons to expect just that. The most obvious is that technologically advanced civilisations of the sort that might, for instance, be able to build a Dyson sphere have access to and the ability to control huge amounts of energy. The ones that are not peaceful wipe themselves out in wars pretty quickly.
Re: "35 / 12 = 2.196666... (6 recurring)."
And 35/12 is not even the right sum to do, since they need to cover interest. I can't do the sum in my head but at 5% a random online thing reckons about 3.8billion/year (320 million a month).
Posted in US flags from the 1970s SEEN ON MOON
Re: Hubble
This isn't right: the moon is effectively at infinity for hubble, as for other telescopes. Even if you're not convinced by this, you should be convinced by one of the earlier links, which is to a picture of the Moon's surface taken by Hubble.
In fact the reason they can't see the Apollo sites is because they can't resolve them. For a telescope with radius D, using light of wavelength lambda, then its angular resolution is approximately theta = lambda/D. Equivalently D = lambda/theta. To resolve something on the moon 1m across, where the moon is about 370x10^6m away, then theta is approximately sin(theta) is 1/(370*10^6). The wavelength of visible light is around 500*10^(-9)m.
So plugging all this in you get D = 185m or for an object of 4m (lunar module is about 4m across) D=46m.
Hubble's mirror is 2.4m, and it's effectively on the surface of the earth (orbit around 600*10^3m). It can work in UV so can gain something there, but it's nowhere near being able to resolve an Apollo site (and neither is an earth-based telescope)
Re: Seriously?
I think the point is that until it started storing these thumbnails it wasn't storing secure data anyway: in particular it was (I assume, based on this not having been discovered earlier as it's a very obvious attack) caching secure data. It does store https things in the history, so there is information that you have visited a secure site, but no secure content was cached, I hope.
Posted in So, what IS the worst film ever made?
Avatar
A competitor in its own right, of course, but in terms of goodness per currency unit it must beat anything else into dust.
@That cannot work
Ah, that's what I'd not understood. If you can't *find* the signal you can't spoof it, and since it is (a) in the noise and (b) pseudorandom, you need to know the pseudorandom sequence to find it. Thanks.
"Encrypted military GPS"
Since GPS is a one-way communication (ie there is no mutual authentication), if you simply listen to the data from the satellite and retransmit it with a suitable delay (and repeat for enough satellites) then how is a GPS receiver meant to know it is hearing your streams rather than the satellites' streams? The only way it could know is by already knowing both its position and the time very accurately, in which case it would not need GPS.
Nothing has changed
Other than them changing the version number for each release: there were always relatively frequent updates. If the version number matters that much, well...
Dirty mirror
fortunately the mirror is not in, or near, the focal plane, so dust is not such a problem as it is on a sensor.
Posted in Spotify tethers future to Facebook
Alternatives to Spotify?
I'm a (paid) user of Spotify. I'm not a Facebook user (and I hope never will be). Although it seems I can still use the service it's become noticably more painful and naggy about connecting to Facebook, of course. What alternatives are out there for legal, advertising-free unlimited music streaming (for money)?
They could have had the money
Apollo programme total cost around $192 billion, in 2011 dollars. Iraq campaign cost around 757 billion in 2011 dollars, Afghanistan campaign cost around 416 billion. Without going into the whole question of whether they should have been in Iraq in the first place, Iraq was a big government project so let's assume they spent double what they needed to on it: they could have gone to the moon on the cost savings.
The CT600 PDF catastrophe
The CT600 PDF disaster is not just a UI problem. We very carefully downloaded a copy of it in plenty of time - months ahead of the filing date, and filled in almost all the numbers. The day before our filing date we filled in the remaining numbers and submitted it. Which failed, eventually leaving us with a CT600 PDF file which would essentially only display a blank page.
This turns out to be because the halfwits at HMRC had //changed the interface// since we had originally downloaded the form, so the old form which we had could not now be submitted, and in fact would not even let us see the numbers in it. Needless to say we didn't find out anything useful from HMRC but worked this out ourselves. We eventually worked around the problem by: reverting to a backup of the CT600 PDF file (a very good thing we kept lots), which would still let us see the numbers, downloading a new one, //type everything in again//, and submit it.
Whoever designed this needs a good killing.
Posted in OED goes the way of all flesh paper
"It's a snip"
The online version is cheap compared to the printed one if you intend to use it for less than 3 years. If you think you might perhaps keep the print one for longer than that, then it's cheaper. Obviously I understand that most of us replace our dictionaries every 6 months or so, but perhaps there remain a few people who might find the printed one worth while.
Seriously: if ever the was an application for something like the Kindle, this is it.
Posted in Solar plasma aurora storm ONGOING UPDATE
Natural radiation
Of course, there is a huge difference between unnatural WRONG AND EVIL radiation and natural GOOD radiation. This is why, for instance, sheep farmers in the lake district have not been able to sell sheep (BAD radiation from Chernonbyl) while we all enjoy a nice holiday in Cornwall (GOOD NATURAL radiation).
It's important to keep these distinctions in mind.
RE: And I thought
You thought wrong then
Carbon sequestration is such a good idea
Storing nuclear waste: we need to store quite small amounts, and it gets less dangerous over time.
Carbon sequestration: we need to store absolutely enormous amounts, and it is dangerous essentially for ever.
Storing nuclear waste: EVIL AND BAD, because it's NUCLEAR and anything NUCLEAR is BAD AND EVIL, and certainly NOT GREEN.
Carbon sequestration: GOOD, because it is GREEN (er, how?) and GREEN IS GOOD.
Resolution
So, this whole "detecting IEDs" thing. This is a satellite, so it's a fair way up: let's say at least 200km if it's going to stay up for any length of time. What kind of resolution does it have (using the real laws of physics, not some made-up tinfoil ones, and not making obviously silly assumptions about being able to do optical interferometry)? Could it be they're just making this stuff up?
Nagative
So, how hard is it to design some kind of device which explodes when it STOPS hearing signals from its owner? Thanks to a little script, my laptop locks its screen when it stops being able to talk to my phone, so I'm guessing not very hard. I suppose the assumption is that terrorists are just very stupid.
Why do you need a 64 bit version?
I mean, what exactly is it buying you?
