7,748 reputation
1628
bio website en.wikipedia.org/wiki/…
location United States
age 70
visits member for 3 years, 3 months
seen 26 mins 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.


Oct
23
comment Weightlessness by a parabolic flight
+ I was taught to distinguish between weight and mass, but I can see your point. If you're teaching non-technical students, that can be too fine a distinction.
Oct
23
comment Weightlessness by a parabolic flight
I can't believe I misspelled "astronaut" twice :)
Oct
22
comment Weightlessness by a parabolic flight
Isn't that a bit pedantic? It's common to say astronaughts in orbit are experiencing weightlessness. If I throw a ball in the air, while it's in the air, it's experiencing exactly the same weightlessness as the astronaught.
Oct
22
revised Why aren't stratospheric balloons compressing their helium to descent?
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Oct
22
answered Why aren't stratospheric balloons compressing their helium to descent?
Oct
22
revised Is airspeed constant or cyclical when flying model aircraft in windy conditions?
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Oct
21
revised Is airspeed constant or cyclical when flying model aircraft in windy conditions?
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Oct
20
answered Is airspeed constant or cyclical when flying model aircraft in windy conditions?
Oct
16
comment Did Felix Baumgartner produce a sonic boom during his jump?
Just a related point. Yes speed of sound is less at higher altitude. That's a problem in jet transports, because their true stall speed increases with altitude, and where the stall speed and the speed of sound come together is called the "coffin corner". That limits the altitude of subsonic aircraft unless they have low wing-loading, like the U2.
Oct
16
comment Is a flawless trick die possible?
@Mathew: There's an even better way to do it. just play god. Film it being thrown down many times, delete all but the cases where it got 3, and post it on Utube. It'll go "viral" :-)
Oct
16
comment Is a flawless trick die possible?
@Mathew: Well, as long as the die is "smart" (having a computer, battery, accelerometer, and momentum wheels inside), then it shouldn't be too hard to program it so if it is simply placed down it will look innocent and not flip :-)
Oct
16
comment Is a flawless trick die possible?
By flawless do you mean it always falls with side 3 up (say), never any other side? Then I think it would have to be active so, for example, if you placed it on the table with side 4 up, it would detect it and spin a momentum wheel or something inside it to flip itself to the 3.
Oct
14
comment Do communicating vessels work when water is moving?
Right. The level in one should equal the bottom level in the other, assuming the tube is directly under the center of the vortex. If it's off-center, I'm not sure.
Oct
12
answered Do communicating vessels work when water is moving?
Oct
12
comment What direction a flag on an object moving in the wind shows?
@Red: Sure. It depends on the relative wind. 50 South - 5 South = 45 South. 2 South - 5 South = -3 South = 3 North. If boat speed downwind = wind speed downwind, the relative wind is 0.
Oct
12
comment What direction a flag on an object moving in the wind shows?
The trailing edge of the flag points directly in the direction of the velocity vector of the relative wind. In common terminology, an air mass whose velocity vector is South is called a North Wind, because if you face North you seem to be facing its source. But don't let that confuse you.
Oct
12
revised atmospheric phenomenon? What causes condensation trails to converge?
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Oct
5
comment Why the shape of rainbow is semicircular after rain why not the whole atmosphere is colorful?
Take an outdoor shower on a clear day with the sun directly above you. You will see the rainbow in a circle around you, because the droplets are all around you, and the ones that are in just the right position will reflect the color (off their opposite surface). But lean against a wall, and now there's a side of you with no droplets. Therefore - not a full circle.
Oct
5
comment Calculating car's acceleration from change in angle of hanging object?
+ @sri: Just make a right triangle by drawing a vertical line from the attachment point, and a horizontal line from the object. Measure the height h and base b of the right triangle. Then just do the proportion. Acceleration a is to gravity g as b is to h.
Oct
4
revised atmospheric phenomenon? What causes condensation trails to converge?
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