6,271 reputation
1322
bio website en.wikipedia.org/wiki/…
location United States
age 69
visits member for 2 years, 7 months
seen 13 hours ago

BS Mechanical Engr.
PhD CS(AI)
CS Prof (4yr)
Numerous consulting jobs.
15 yr at http://www.pharsight.com
Published book on CS & several articles
4 kids, 2 grand
Pilot(student)

P.S. The picture is a Beta-prime distribution. It shows the program speedup factors you can get if you see a problem twice in 2, 3, 4, and 5 samples.


Apr
14
comment What is a linear probability density function?
@gj255: What you would do is take your sample of n velocities and sort them to get an empirical distribution. Then see which $av+b$ line fits it best.
Apr
13
answered What is a linear probability density function?
Apr
13
comment Duration of Satellite orbit in the shadow of the Earth
In the past, I've been guilty of giving complete answers to homework questions, rather than nudging the OP in the direction of figuring it out.
Apr
12
comment Why Don't Birds Stall?
Stalling is an effective way to dissipate excess energy. (That's why cars have brakes.) Small airplanes stall when they land. I suppose birds do too.
Apr
11
comment How much weight is lifted from each side?
None of the heights matter. What does matter is how the weight is distributed. Is the weight more toward the front, or more toward the back? Is it concentrated in the middle, or is a lot of it in the very ends? Are you lifting both ends at the same time, or one end at a time?
Apr
10
comment On the Existence of Interstellar Meteoroids
Maybe you could provide a link to the video, and what is 36:45? Thanks.
Apr
10
comment Why is there this asymmetry between the two foci of an orbital ellipse?
@EmilioPisanty: Thanks. You're right - except that the center of the cone is not the center of the ellipse, except for a circle. Easiest way to see that is to cut the cone on a plane almost, but not quite, parallel to the edge, so as to create an ellipse of very high eccentricity.
Apr
8
comment How “earthing” electricity work?
+ @MukulKumar: They don't. The reason the earth is conductive is because it contains a certain amount of water, and plenty of ions in that water.
Apr
6
comment Beryllium Vacuum Sphere Boat/Aircraft
In air, the weight of air excluded from a given volume decreases with altitude, so a balloon of fixed volume has an altitude limit. High altitude balloons must be capable of expanding.
Apr
4
answered Does the wing-propeller plane or jet-plane struggle up at the high altitudes because of low pressure?
Mar
31
revised Speed of liquid being blocked at end of pipe
added 4 characters in body
Mar
31
comment Water falling, why does it spin?
It is very difficult to make a faucet, or pour from a cup, without imparting some rotation to the water. As @Parth said, it will rotate faster as the diameter of the stream decreases.
Mar
28
comment Toy helicopters at very high altitude
@GlenTheUdderboat: Maybe a bit. What ground effect does is increase the lift/drag ratio.
Mar
28
revised Toy helicopters at very high altitude
added 138 characters in body
Mar
28
answered Toy helicopters at very high altitude
Mar
27
revised Aren't all collisions elastic at some level?
added 31 characters in body
Mar
27
answered Aren't all collisions elastic at some level?
Mar
24
awarded  Nice Answer
Mar
23
revised What is sound in terms of acoustic sources?
added 210 characters in body
Mar
23
answered What is sound in terms of acoustic sources?