Bayesian email filters take advantage of Bayes' theorem.Spam filters use Bayesian spam filter to filter out junk email from the record email.Calculate the probability that mail will be a junk taking some key words in to
consideration(refinance,stock,Viagra...these words may have high Bayesian probability).Here you get statistics on how often tokens show up in two bodies of mail, (spam and good,) and then calculate the a statistical value that a single mail is spam by looking at the tokens in it. The more mail in the good and spam mail bodies, the better the filter is "trained".
Bayes' theorem, in the context of spam, says that the probability that an email is spam, given that it has certain key words in it is:
π
It represents the ratio of any circle's circumference to its diameter,approximately equal to 3.14159.π itself has an infinite decimal expansion; because π is an irrational number, its decimal expansion never ends and does not repeat. Simple way of calculating π is by drawing a large circle, then measuring its diameter and circumference, since the circumference of a circle is always π times its diameter.
when we find some thing we can't explain in math we said it is π(pi).So there is question to answer why pi appears many places in Physics, Relativity and number theory seemly unrelated places.
when we droop needles randomly to a sheet of line paper probability of needle will cross a line is equal to the pi(Buffon's needle).
Let the length of the needle is one unit and the distance between the lines is also one unit. There are two variables, the angle at which the needle falls (theta) and the distance from the center of the needle to the closest line (D).
To calculate pi from the needle drops, simply take the number of drops and multiply it by two, then divide by the number of hits, or
2(total drops)/(number of hits) = pi (approximately).
Car Remote
The system consists of a remote, commonly called a "keyfob" and a reciever module located somewhere on the car.When you press the keyfob button, a signal is sent out by the keyfob. This signal includes a numeric pass code.car remote has one to one mapping with the car.but all remotes are in the same frequency.every remote emit numerical code only one car identifies it.Rolling code.every time hit the key it sends different signal to the car.If the combination agrees with the stored information that has been programmed into the receiver module, the doors unlock, lock, or whatever allocated happens.The change is predictable as long as we know the algorithm,it may be simple as adding a 1.
Gambling
Math applies to gambling. Booky wanted to take equal amount of money on each side of the game. Booky always balance two side.But sometime one team is better than the other,he have to adjust the point spread.He have to drop bets to the weak side and keep the balance.He keep the balance he doesn't have to pay for the winner from his own pocket,they get paid from the losers money.For his balance spread he makes 4 1/2% profit for the all the action he takes.
PEMS
PEMS-freeway performance evaluation monitoring system
PEMS is designed to predict optimum traffic route and travel time.There are sensors buried in the roads,that count cars,trucks traffic on the road.And that information is sent to a computer.
constructional theory,point area point volume of flows.Traffic flew like any other fluid system,there are imperfection obstacles,that proves the system to optimize it by reducing its resistance.
Fairy Sequence
Fraction specially a fairy sequence.Say we begin slicing oranges to lot of oranges,but the rule is we can never repeat a cut.First orange cut to a 1/2.Next orange we take 1/3.next 1/4 and next 1/5.In the end we left many orange slices with vary in size.When you place smallest to largest the form a fairy sequence.
F1=(0/1,1/1)
F2=(0/1,1/2,1/1)
F3=(0/1,1/3,1/2,2/3,1/1)
F4=(0/1,1/4,1/3,1/2,2/3,3/4,1/1)
F5=(0/1,1/5,1/4,1/3,2/5,1/2,3/5,2/3,3/4,4/5,1/1)
this is used in book keeping.
why there is no Nobel Prize for Maths
Since 1901, the Nobel Prize has been honoring men and women from all corners of the globe for outstanding achievements in physics, chemistry, medicine, literature, and for work in peace.But there is no Nobel price for mathematics.Mathematicians says Nobel's wife or his mistress had an affair with the mathematician Mittag-Leffler and he doesn't want to share his price with his rivals.But this can't be truth because Alfred Nobel never married.
There are several possible reasons why Nobel did not create a prize for mathematics.Nobel price is for those inventions or discoveries of greatest practical benefit to mankind,but mathematics is not considered as practical science,this would explain the lack of a Mathematics prize.Another possible reason is that there was already a well known Scandinavian prize for mathematicians.And several prizes in Mathematics have similarities to the Nobel Prize.
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