Without any more info, it sounds like he should have been able to set up some sort of landmark (bright cloth on a tree) while setting up shelter. Or he could have had a whistle or a flashlight.
But I don't know enough of the details of how the searchers were looking, etc., but I find it surprising that the searchers came that closed and missed him. Probably because he moved from where his friend had last seen him.
So yes, maybe that jacket would have saved him, but most likely, something under a pound and under $10 would have saved him also.
Yeah, it does get crazy cold in Wyoming. Colder than in the Cascades in WA. I've spent the night [planned] in a snow shelter in the mountains in WA, and I was perfectly cozy.
You should not have to reheat someone suffering from mild hypothermia. Given dry clothes, water, and calories, and brought out of the wind, they should be able to heat themselves up on their own.
If they really needed to be reheated, their hypothermia was not by any means mild.
And there is no way in hell that the batteries would have lasted him overnight.
His problem was that he was unprepared and stupid. No amount of equipment will save the unprepared and foolhardy.
Mistake number 1. He and his partner getting separated.
Mistake number 2. Not being skilled/equipped enough to navigate once lost.
Mistake number 3. Wandering around when he had no idea where the hell he was going. Your best bad to survival is to stay where you are (or find/make a nearby shelter and stay there).
Mistake number 4. Falling in the river. Don't ask me how he managed that one.
Mistake number 5. Not carrying sufficient clothing/equipment to survive the night.
When you are out in the wild in the winter, you need to carry enough gear so that you can survive the night. It doesn't take much gear or much money or much weight. Extra water and food. Some cheap extra clothes. A cheap emergency blanket. A cheap emergency bivy sack. He can dig a snow trench (if he didn't have a snow shovel in the snow mobile, he's a moron who deserves to die in an avalanche) or find shelter in a tree-well.
Never use cotton in cold/wet conditions. It is very poor at keeping heat in when wet. And it is slow to dry. Polyester or fancy wicking fabrics function much better. You can find cheap polyester shirts/underpants for near the same price as cotton.
Just turning on your coat would not be sufficient. You need to get rid of the wet clothes. There is a reason why extra clothes is one of the 10 essentials.
For more severe hypothermia, it will be necessary to warm the victim. Certainly if you are in a group, someone else can warm you up. If you are solo, your best bet will be to prevent that situation from ever occurring. And I doubt that anyone soloing would want to carry the extra weight for an emergency battery-powered heat-you-up blanket.
Re:$500 isn't anything for many skiers
on
Self-Warming Jackets
·
· Score: 2, Informative
The $150 pants you're talking about are probably Goretex or a Goretex clone that make the pants both waterproof and breathable. Cheap nonbreathable pants are fine if you aren't exerting yourself much, but you work up a sweat, you'll be as wet on the inside as on the outside.
Normally I wear waterproof/breathable stuff when I'm in the mountains. I'll take the cheap stuff only if I want to travel really compact and light (i.e. trail-run), and I'll take the cheap stuff in addition if I am glissading.
One claim is that once you have the accurate physics, you can tweak it and warp it to your satisfaction. An analogy could be that you cannot paint impressionistically if you cannot paint realistically.
You could also use computer stunt creatures that do not exist (aliens, dragons, an honest Enron exec) or perform motions that would be hard to convince humans/animals to do (pig & elephant going at it, a'la Southpark).
No, it is not anywhere near solved. Funny that the MIT AI geniuses of the 50's expected vision to be solved in ten years.:) We still don't know how to take a bunch if pixels/voxels/polygons and determine that they are a toilet. Or even "easier" problems such as perfect segmentation or stereo-matching.
Systems like the 10+ yard line in football aren't even perfect (what if shadows move or the sun/clouds do funky stuff or green uniforms interfere?). They have attendants present to correct quickly any errors.
When you use forces, as you suggest in the second paragraph, you are not doing forward/inverse kinematics, but rather forward/inverse dynamics, a much harder problem.
And things like trees and jello behave passively, that is they don't produce any forces on their own from muscles, motors, etc.
My guess is what you are referring to in the first paragraph is simple spring-mass systems. Modal analysis can be used to obtain more accurate deformations for things like trees.
But if you want to simulate humans, you need to model the human's muscles as well if the human is anything but limp. The interaction can be very complex (especially given closed loop situations such as two legs on the ground).
Sorry, but you are not very clued in on the research. Petros did not make a physical simulation of a human walking. That had been done many years earlier. Researchers at Georgia Tech [Hodgins, et al.] and U Penn [Badler, et al.] have focused on simulated humans since the early 90's, simulating motions from running to bicycling to diving.
Petros's work was on integrating these motions together: so a character could walk, trip, dive, land, roll, and stand back up again. He used support vector machines to learn the domains of acceptable pre- and post- conditions of different movements and plan the transitions.
The researcher performed this work for his Ph.D. thesis at Toronto. Though he is most likely continuing the line of research as a professor, the article is about his thesis work.
A few years back, the Dean Boyd even
came to us [TAs] complaining that we weren't
doing enough to prevent cheating -- she was
getting sick and tired of handling all the
cases we passed to her. We were pissed off
that she was yelling at us, so we proposed
having a mock "cheat bust" where we pull an
actor out of lecture, accuse him of cheating,
and haul him away handcuffed in front of
everyone else... she got even more mad...
Avoid the Boyd! w00t!
Anyway, more seriously, I feel proud having
gone to a school which would rather go through
the pains of prosecuting cheaters rather than
let them slide by... and would not water down
grades... heh, 3.55 GPA required to get
highest honors.
For one of the classes I TAed at GT, we were too lazy at the time to get the cheatfinder working
under our conditions... We told the students
we were using cheatfinder, but we never did.
We still caught many [lazy/stupid] cheaters.
There was one time they had to write some
sockets code and turn in their interactions
with our test server.
Bob turned in "Congratulations, gt1234a [Bob's uid] has correctly communicated with the server. You get a 100!"
Sam turned in "Congratulations, gt1234a [still Bob's uid] has correctly communicated with the server. You get a 100!"
We all have the SIGGRAPH paper submission
deadline on Jan 9. Our lab was plenty busy
today (as well as yesterday and any other day
between the start of break and the deadline).
Yeah, you're right... got caught being a little
too laymanish. So allow me to nitpick:
Technically, an nth order method means that
locally the error is a (n+1)-degree polynomial.
Global error depends on convergence and stability;
it's even possible for performance to get worse
by doubling the timestep.
> (joystick input) are not known explicitly. It
> doesn't have to be a full-blown 4th-order Runge-> Kutta solution, but some form of numerical
> integration is necessary. A simple trapezoidal > rule might do nicely.
Netlib's code is as rock-solid as it gets.
Someone earlier here mentioned Numerical
Recipes. It's a mediocre book, and some
of its routines do not work as well as
versions in Netlib.
And a personal pet peeve: NR coded a SQR macro
is something like:
Anyone well versed in the ANSI C spec will
notice that bad things happen when you do
norm=sqrt(SQR(x)+SQR(y)).
Netlib has LAPACK, which solves most any
linear algebra problem (they come up in physics)
better than your or I will ever be able to
figure out.
Yes, most of that code is Fortran, but so what?
First of all, the compiled Fortran code will be
much better optimized because there are no
annoyances such as pointer aliasing. Second,
it is easy today to compile the Fortran code
as a black box and link the library in with your
C/C++ code.
It amazes me how people can drool through a
calculus course and then proclaim themselves
experts on slashdot.
First of all, Simpson's method does not
create an "exponential polynome." It models
a curve locally as a parabola.
Second, this method is useless in many situations
where one integrates over time. Simpson's rule
is designed to find the area under a curve.
Yes, distance is just area under a velocity
curve, but you are not given the velocities
a priori. You have to solve for them on the
spot, and even worse, velocities can be
influenced by the current position. In fluids
and soft-body deformations, things can get
even uglier. Some of the better methods for
numerically integrating through time involve
estimating the next values in time and solving a
system of equations using old and new values to
get a more accurate result (very hand-wavy explanation).
Slashdot Mirror
Don't forget about windchill. When it's
gusting 40-50 mph, it can get quite cold.
On top of a big mountain, the gusts can top
100 mph in bad weather.
That's also why the motorcyclists posting
here are all for this product... their
bikes create the wind.
Without any more info, it sounds like
he should have been able to set up some
sort of landmark (bright cloth on a tree)
while setting up shelter. Or he could have
had a whistle or a flashlight.
But I don't know enough of the details of
how the searchers were looking, etc., but I
find it surprising that the searchers came that
closed and missed him. Probably because he
moved from where his friend had last seen him.
So yes, maybe that jacket would have saved
him, but most likely, something under a pound
and under $10 would have saved him also.
Yeah, it does get crazy cold in Wyoming.
Colder than in the Cascades in WA. I've
spent the night [planned] in a snow shelter
in the mountains in WA, and I was perfectly
cozy.
You should not have to reheat someone
suffering from mild hypothermia. Given
dry clothes, water, and calories, and
brought out of the wind, they should be
able to heat themselves up on their own.
If they really needed to be reheated, their
hypothermia was not by any means mild.
And there is no way in hell that the
batteries would have lasted him overnight.
His problem was that he was unprepared and
stupid. No amount of equipment will save
the unprepared and foolhardy.
Mistake number 1. He and his partner getting
separated.
Mistake number 2. Not being skilled/equipped
enough to navigate once lost.
Mistake number 3. Wandering around when he
had no idea where the hell he was going.
Your best bad to survival is to stay where
you are (or find/make a nearby shelter and
stay there).
Mistake number 4. Falling in the river.
Don't ask me how he managed that one.
Mistake number 5. Not carrying sufficient
clothing/equipment to survive the night.
When you are out in the wild in the
winter, you need to carry enough gear
so that you can survive the night. It doesn't
take much gear or much money or much weight.
Extra water and food. Some cheap extra clothes.
A cheap emergency blanket. A cheap emergency
bivy sack. He can dig a snow trench (if he didn't have a snow shovel in the snow mobile, he's a moron who deserves to die in an avalanche)
or find shelter in a tree-well.
Never use cotton in cold/wet conditions.
It is very poor at keeping heat in when
wet. And it is slow to dry. Polyester
or fancy wicking fabrics function much better.
You can find cheap polyester shirts/underpants
for near the same price as cotton.
Just turning on your coat would not be
sufficient. You need to get rid of
the wet clothes. There is a reason why extra
clothes is one of the 10 essentials.
For more severe hypothermia, it will be
necessary to warm the victim. Certainly if
you are in a group, someone else can warm
you up. If you are solo, your best bet will
be to prevent that situation from ever
occurring. And I doubt that anyone soloing
would want to carry the extra weight for
an emergency battery-powered heat-you-up
blanket.
The $150 pants you're talking about are
probably Goretex or a Goretex clone that
make the pants both waterproof and
breathable. Cheap nonbreathable pants
are fine if you aren't exerting yourself
much, but you work up a sweat, you'll be as
wet on the inside as on the outside.
Normally I wear waterproof/breathable stuff
when I'm in the mountains. I'll take the
cheap stuff only if I want to travel really
compact and light (i.e. trail-run), and I'll
take the cheap stuff in addition if I am
glissading.
Hey, if they do make every SIGGRAPH paper
a story a year later, at least there won't
be repeats.
One claim is that once you have the accurate
physics, you can tweak it and warp it to your
satisfaction. An analogy could be that you
cannot paint impressionistically if you
cannot paint realistically.
There are also many other applications for
this and similar lines of research (including
my current research):
Education: Teach martial arts and use
the system to visualize complex moves.
Choreography: Rapidly prototype complex
dance/gymnastics sequences realistially.
Art: If this tool can be made intuitive
for a novice user, character animation may
finally become an accessible art medium
for the masses.
You could also use computer stunt creatures that
do not exist (aliens, dragons, an honest
Enron exec) or perform motions that would be
hard to convince humans/animals to do
(pig & elephant going at it, a'la Southpark).
No, it is not anywhere near solved. Funny :) We still
that the MIT AI geniuses of the 50's expected
vision to be solved in ten years.
don't know how to take a bunch if pixels/voxels/polygons and determine that they
are a toilet. Or even "easier" problems such as
perfect segmentation or stereo-matching.
Systems like the 10+ yard line in football
aren't even perfect (what if shadows move or
the sun/clouds do funky stuff or green uniforms interfere?). They have attendants present to
correct quickly any errors.
When you use forces, as you suggest in
the second paragraph, you are not doing
forward/inverse kinematics, but rather
forward/inverse dynamics, a much harder
problem.
And things like trees and jello behave
passively, that is they don't produce any
forces on their own from muscles, motors, etc.
My guess is what you are referring to in the
first paragraph is simple spring-mass systems.
Modal analysis can be used to obtain more
accurate deformations for things like trees.
But if you want to simulate humans, you need
to model the human's muscles as well if the
human is anything but limp. The interaction
can be very complex (especially given closed
loop situations such as two legs on the ground).
Sorry, but you are not very clued in on the
research. Petros did not make a physical
simulation of a human walking. That had been
done many years earlier. Researchers at
Georgia Tech [Hodgins, et al.] and U Penn
[Badler, et al.] have focused on simulated
humans since the early 90's, simulating motions
from running to bicycling to diving.
Petros's work was on integrating these motions
together: so a character could walk, trip,
dive, land, roll, and stand back up again.
He used support vector machines to learn
the domains of acceptable pre- and post-
conditions of different movements and plan
the transitions.
The researcher performed this work for his
Ph.D. thesis at Toronto. Though he is
most likely continuing the line of research
as a professor, the article is about his
thesis work.
Wow, the light test... that's some type of
fancy-shmancy parallel algorithm!
You should patent it!
P.S. Yo Tang... I'll email ya tomorrow...
A few years back, the Dean Boyd even
came to us [TAs] complaining that we weren't
doing enough to prevent cheating -- she was
getting sick and tired of handling all the
cases we passed to her. We were pissed off
that she was yelling at us, so we proposed
having a mock "cheat bust" where we pull an
actor out of lecture, accuse him of cheating,
and haul him away handcuffed in front of
everyone else... she got even more mad...
Avoid the Boyd! w00t!
Anyway, more seriously, I feel proud having
gone to a school which would rather go through
the pains of prosecuting cheaters rather than
let them slide by... and would not water down
grades... heh, 3.55 GPA required to get
highest honors.
For one of the classes I TAed at GT, we were too lazy at the time to get the cheatfinder working
under our conditions... We told the students
we were using cheatfinder, but we never did.
We still caught many [lazy/stupid] cheaters.
There was one time they had to write some
sockets code and turn in their interactions
with our test server.
Bob turned in "Congratulations, gt1234a [Bob's uid] has correctly communicated with the server. You get a 100!"
Sam turned in "Congratulations, gt1234a [still Bob's uid] has correctly communicated with the server. You get a 100!"
[names changed to protect the moronic]
P.S. Zorba... wassup! long time no see!
what do they think about Bughouse players? :)
We all have the SIGGRAPH paper submission
deadline on Jan 9. Our lab was plenty busy
today (as well as yesterday and any other day
between the start of break and the deadline).
my apartment doesn't even have a computer in it.
And I like it that way.
It's a nice change of pace from working all day
in front of a computer.
Yeah, you're right... got caught being a little
too laymanish. So allow me to nitpick:
Technically, an nth order method means that
locally the error is a (n+1)-degree polynomial.
Global error depends on convergence and stability;
it's even possible for performance to get worse
by doubling the timestep.
> (joystick input) are not known explicitly. It
> doesn't have to be a full-blown 4th-order Runge-> Kutta solution, but some form of numerical
> integration is necessary. A simple trapezoidal > rule might do nicely.
But Runge-Kutta is *not* that much more work.
Netlib's code is as rock-solid as it gets.
Someone earlier here mentioned Numerical
Recipes. It's a mediocre book, and some
of its routines do not work as well as
versions in Netlib.
And a personal pet peeve: NR coded a SQR macro
is something like:
float _secret;
#define SQR(x) (_secret=(x),_secret*_secret)
Anyone well versed in the ANSI C spec will
notice that bad things happen when you do
norm=sqrt(SQR(x)+SQR(y)).
Netlib has LAPACK, which solves most any
linear algebra problem (they come up in physics)
better than your or I will ever be able to
figure out.
Yes, most of that code is Fortran, but so what?
First of all, the compiled Fortran code will be
much better optimized because there are no
annoyances such as pointer aliasing. Second,
it is easy today to compile the Fortran code
as a black box and link the library in with your
C/C++ code.
It amazes me how people can drool through a
calculus course and then proclaim themselves
experts on slashdot.
First of all, Simpson's method does not
create an "exponential polynome." It models
a curve locally as a parabola.
Second, this method is useless in many situations
where one integrates over time. Simpson's rule
is designed to find the area under a curve.
Yes, distance is just area under a velocity
curve, but you are not given the velocities
a priori. You have to solve for them on the
spot, and even worse, velocities can be
influenced by the current position. In fluids
and soft-body deformations, things can get
even uglier. Some of the better methods for
numerically integrating through time involve
estimating the next values in time and solving a
system of equations using old and new values to
get a more accurate result (very hand-wavy explanation).