On 23/04/2011 14:38, Olin Lathrop wrote:
> Properly retagged.
>
> Oli Glaser wrote:
>> Yes, it's a very basic point I was trying to make, about just what you
>> mention - getting *less* data. This is not always the objective.
> But it certainly is in the case we are talking about.  Imagine if a exerc=
ise
> machine display updated often to show "instantaneous" power.  People woul=
d
> be upset that the reading jumped around a lot and was hard to read.  A
> second peak-holding display would cost more and confuse people since it h=
ad
> no real benefit.  And then there is the big question about what exactly
> "instantaneous" means.  The power output is a bit like a fractal in that =
it
> gets rougher the closer you look to some extent.

Why would the exercise machine display have to update quicker just=20
because you are sampling quicker, or have a second display?
The data could be stored until you wish to see it.
Of course "instantaneous" needs defining - I was thinking somewhere=20
between  10us - 100ms.
Anything a bit quicker than the normal >1 second that Russell mentioned=20
I guess.
Imagine some weight training machine - this might want to sample things=20
quickly. Or perhaps an electronic punch bag.

This is all pure conjecture, I have very little knowledge of exercise=20
equipment production, I guess you would have to ask a bunch of experts=20
in the field of athletics to get a better idea of what is needed.=20
However, I don't feel it's silly to wonder about anything, even if you=20
are off the mark - that's what engineers/scientists do. If they didn't=20
nothing would ever change. Besides, I thought this was a discussion ;-)

>> My point is simply what if someone wants to know their maximum
>> instantaneous power attained?
> Then they're being silly, at least for the applications these machines ar=
e
> designed for.  But again, what is "instantaneous"?  100ms, 10ms, 1ms?
>
> Also, as the time period gets shorter much of the apparent power is likel=
y
> coming from momentum effects.  For example, I can appear to put out a lot=
 of
> power for a short time by climbing on a chair then jumping down on
> something.  However, this is just release of stored energy (potential in
> this case) that my body put out earlier over a longer time period.
>
>
> ********************************************************************
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