Invisible <voi### [at] devnull> wrote:
> Try walking across the room. Trust me, this requires some pretty damned
> precise computations. Don't believe me? Drink some alcohol, and try the
> same task. Hard, isn't it? You know robotics engineers have struggled
> for years to make a bipedal robot that can perform the same apparently
> trivial task?
>
> Balance is hard. A few grams one side or the other and you fall over.
> That sounds pretty precise to me. And yet people ride bicycles. How many
> robots have you seen ride a bicycle?
>
> You say people can't recognise a familiar face with /certainty/, but I
> reject that. A computer might look at a face and rate the probability of
> it belonging to various people, but when I see a person I know, I *know*
> exactly who I'm looking at. Instantly. What's more, when I see a
> computer-generated image of Davy Jones, I recognise it as resembling
> Bill Nighy. How many computer facial recognition programs can do that?
> Again, sounds pretty damned accurate to me.
>
> There are computer programs that compute a "fingerprint" of a piece of
> music, and can supposedly recognise the same recording that has been
> altered slightly. But a human listener can recognise the same piece of
> music performed by a completely different group, and a totally unrelated
> style. No computer can do that. And it's not just that humans use more
> "fuzzy" and less "precise" matching to do their recognition; if that
> were the case, the matching would just be really unreliable. But
> actually, humans are REALLY FRIGGING GOOD at this stuff.

You have a grave misconception here:
As has been said before, the human brain is anything but precise. It actually is
very very good at correcting errors and adapting to them. Walking
across a room is not a precalculated series of movements like it would be for
most robots. The brain is constantly regulating all your movements dependent on
the millions of information it receives from your body.
Whenever anything happens that's not quite as it was "planned" it will just
change the movement slightly without your conciousness even noticing.

Facial recognition is much the same. The human brain has dedicated structures
for exactly that purpose. If they are damaged, the person suddenly can't
recognize faces anymore. I once saw a report about someone having a stroke and
losing this ability. He was unable to relearn this ability, because the
"dedicated hardware" could not be "emulated in software", so to speak. Those
dedicated structures have evolved over millenia for this one single purpose. You
cannot expect a computer to perform with the same efficiency on a general
purpose processor.

And about accuracy of facial recognition:
How sure you are about recognizing someone depends largely on how well you know
that person and if there's other persons you know that look alike. If someone
has a distinct face than your confidence of recognition is high. But if you look
at identical twins you'll be less sure of recognizing them correctly.
So how can you say you are 100% sure you recognized someone? It's just that your
confidence is high enough for you to think you are 100% sure.

Regards
Aydan

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On 07/06/2011 04:28 PM, Aydan wrote:

> Walking
> across a room is not a precalculated series of movements like it would be for
> most robots.

...which is why the robot is wrong. The *correct* way to navigate 
unknown terrain is to constantly monitor and adapt to your surroundings.

> Whenever anything happens that's not quite as it was "planned" it will just
> change the movement slightly without your conciousness even noticing.

Yes. And these changes are very, very precise. If they weren't, you'd 
fall over. The fact that it does this in a feedback loop doesn't negate 
the need for very exact, very fine controls.

> Facial recognition is much the same. The human brain has dedicated structures
> for exactly that purpose. If they are damaged, the person suddenly can't
> recognize faces anymore.

Like I said: The human brain is an elaborate special-purpose 
computational device which is ridiculously good at the things it's 
designed for, and drastically less good at the things it isn't designed for.

> And about accuracy of facial recognition:
> How sure you are about recognizing someone depends largely on how well you know
> that person and if there's other persons you know that look alike.

People have actually done research on this. The vast majority of people 
recognise other people with stunning accuracy. Not that they /think/ 
they do, but that you can actually /measure/ this.

That said, it's also been found that people from a different ethnic 
group tend to look more uniform to you than they do to people belonging 
to that ethnic group. Whether this is a genetic or environmental thing 
is a subject of some debate. (Although it seems quite reasonable to me 
that it's simply a calibration issue.)

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>> But a human listener can recognise the same piece of music
>> performed by a completely different group, and a totally unrelated
>> style. No computer can do that.
>
> This is incorrect. I watched our server listen to someone singing
> "Yesterday" on American Idol and our computer correctly recognizing it
> as a Beatles song.

This would be a rather stunning result for AI. Last time I checked, AI 
is poor to the point of being utterly useless for most if not all 
recognition tasks. Even something trivial like OCR doesn't work very 
well yet.

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On 6/7/2011 8:28, Aydan wrote:
> confidence is high enough for you to think you are 100% sure.

Or, more precisely, you can be 100% sure and still be wrong. :-)

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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On 6/7/2011 8:39, Invisible wrote:
> This would be a rather stunning result for AI.

It wasn't even what you'd call AI nowadays. It was just pattern matching.

Why are you using the subjunctive, as if this is a fictional story?

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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On 07/06/2011 04:40 PM, Darren New wrote:
> On 6/7/2011 8:28, Aydan wrote:
>> confidence is high enough for you to think you are 100% sure.
>
> Or, more precisely, you can be 100% sure and still be wrong. :-)

If you want to split hairs, even events with probability 1 can fail to 
happen. (Contrary to what your introductory statistics book probably 
told you...)

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On 07/06/2011 04:41 PM, Darren New wrote:
> On 6/7/2011 8:39, Invisible wrote:
>> This would be a rather stunning result for AI.
>
> It wasn't even what you'd call AI nowadays. It was just pattern matching.

Given that two different, unrelated recordings of the same piece of 
music have entirely unrelated waveforms, I'm not sure how you can claim 
that simple pattern matching would find such a complex similarity.

> Why are you using the subjunctive, as if this is a fictional story?

Damnit, now I have to go look up what a "subjunctive" is...

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On 07/06/2011 04:45 PM, Invisible wrote:

> Damnit, now I have to go look up what a "subjunctive" is...

NAAAARGH! IT BURNS! >_<

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On 6/7/2011 8:45, Invisible wrote:
> I'm not sure how you can claim that
> simple pattern matching would find such a complex similarity.

I'm not saying it would. I'm saying it *did*.

>> Why are you using the subjunctive, as if this is a fictional story?
> Damnit, now I have to go look up what a "subjunctive" is...

Yep.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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Invisible <voi### [at] devnull> wrote:
> On 07/06/2011 04:28 PM, Aydan wrote:
>
> > Walking
> > across a room is not a precalculated series of movements like it would be for
> > most robots.
>
> ...which is why the robot is wrong. The *correct* way to navigate
> unknown terrain is to constantly monitor and adapt to your surroundings.
>
> > Whenever anything happens that's not quite as it was "planned" it will just
> > change the movement slightly without your conciousness even noticing.
>
> Yes. And these changes are very, very precise. If they weren't, you'd
> fall over. The fact that it does this in a feedback loop doesn't negate
> the need for very exact, very fine controls.

I'd say the changes are NOT precise but they are minute and the update rate is
fast. So fast that an error in an update will be negated with the next update
and the control loop is adapted constantly to minimize errors. It's still not
what I would call precise.

If the human body would be capable of precice movement then you should be able
to repeat movements exactly every time you do them. But that's not how it turns
out.
Try throwing a ball at something. You won't be able to hit the same spot twice
in a row. If you practice very very hard, you might get close but you still
won't hit the same spot every time.

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