. *.kbs. . , , , :
l ("hypothesis", "plane", 0.5, bayes_rule ([ contrib ("plane_factors", 1, 0.001), contrib ("plane_speed", 5, 1), contrib("plane_cost", 5, 0.5),
contrib ("plane_dist", 10, 0.9) ]), "Use a plane","", [ ])
cl ("hypothesis", "car", 0.5, bayes_rule ([ contrib ("car_factors", 1, 0.9),
contrib ("car_speed", 5, 0.9), contrib ("car_dist", 2, 0.8), contrib ("car_cost", 3, 0.9) ]), "Use a car", "", [ ])
cl ("hypothesis", "train", 0.5, bayes_rule ([ contrib ("rail_factors", 1.1, 1),
contrib ("drive_yourself", 1.1, 1), contrib ("rail_speed", 1.1, 0.1),
contrib ("rail_dist", 2, 1), contrib ("rail_cost", 5, 1) ]), "Use a train", " ", [ ])
cl ("intermediate", "rail_factors", 0.5, and_rule ([ "drive_yourself", "rail_speed", "rail_dist", "rail_cost" ]), "use of a train is appropriate", "", [ ])
cl ("intermediate", "rail_speed", 0.5, num_map_rule ("speed", [ nummap (60, 1), nummap (150, 0) ]), "Desired journey speed permits rail use", "",
[context ("drive_yourself", 5, 0) ])
cl ("intermediate", "rail_dist", 0.5, num_map_rule ("distance", [nummap (50, 0), nummap (200, 1), nummap (350, 0) ]), "Is the use of a train sensible", "", [context("drive_yourself", 5, 0) ])
cl ("intermediate", "rail_cost", 0.5, num_map_rule ("cost", [ nummap (10, 0), nummap (20,1) ]), "Desired cost per mile is possible using a train", "", [context ("drive_yourself", 5, 0) ])
cl ("data", "drive_yourself", 0.5, yesno_rule,"Do you want to drive yourself?", "", [ ])
cl ("data", "distance", 0.5, num_value_rule (0.1,30000), "what is the distance of the journey in miles?", "", [ ])
cl ("data", "speed", 0.5, num_value_rule (1, 1300), "what is the required average speed for the journey (mph)?", ", [ ])
cl ("data", "cost", 0.5, num_value_rule (1, 50), "How much are you prepared to pay per mile?", "This system assumes the costs:\n plane: 30 cents/mile\n train: 25 cents/mile \n car: 20 cents/mile", [ ])
...
. data - , . evaluate , eval, . , . evalbody. , eval:
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evalbody (not_rule (Clname), Desc, Prior,
num (Val), Anceslst, Mode):
eval (not_rule, _, Clname, _, num (Val1), Anceslst, Mode),
Val = 1 Val1.
evalbody (and_rule ([ ]), _, _, num (1), _, _):!.
evalbody (and_rule ([ Clname | T ]), Desc, Prior,
num (Val), Anceslst, Mode):
eval (and_rule, _, Clname, _, num (Val1), Anceslst, Mode),
evalbody (and_rule (T), Desc, Prior, num (Val2), Anceslst, Mode),
min (Val1, Val2, Val).
evalbody (or_rule ([ ]), _, _, num (0), _, _):!.
evalbody (or_rule ([ Clname | T ]), Desc, Prior,
num(Val), Anceslst,Mode):
eval (or_rule, _, Clname, _, num(Val1), Anceslst, Mode),
evalbody (or_rule(T), Desc, Prior, num (Val2), Anceslst, Mode),
max (Val1, Val2, Val).
evalbody (bayes_rule ([ ]), _, Prior, num (Prior), _, _):!.
evalbody (bayes_rule ([ contrib (Clname, Inc, Dec) | T ]), Desc, Prior,
num (Val), Anceslst, Mode):
eval (bayes_rule, _, Clname, Pri, num (Val1), Anceslst, Mode),
evalbody (bayes_rule (T), Desc, Prior, num (Val2), Anceslst, Mode),
combinebayes (Pri, Val1, contrib (Clname, Inc, Dec), Val2, Val).
evalbody (sym_map_rule (Clname, L), Desc, Prior, num (Val),
Anceslst, Mode):
eval (sym_map_rule, _, Clname, _, Val1, Anceslst, Mode),
calcsymrule (sym_map_rule (Clname, L), Prior, Val1, Val).
...
, . PRIOR, BAYES . combinebayes, Ans:
ombinebayes (ClPrior, ClVal, contrib (_, Inc, Dec), RestVal, Ans):
probtoodds (RestVal, RestOdds),
bayesfactor (ClVal, ClPrior, Dec, Inc, F),
Odds = F * RestOdds,
oddstoprob (Odds, Ans).
combinebayes probtoodds, :
ROOS = PROB / (1 PROB).
Bayesfactor F, , PRIOP < PROB PRIOR > PROB:
bayesfactor (Prob, Prior, Dec, Inc, F):
Prior > = Prob,
!,
probtocert (Prob, Prior, Cert),
F = ((1 Dec) * (Cert + 5) / 5) + Dec.
bayesfactor (Prob, Prior, Dec, Inc, F):
probtocert (Prob, Prior, Cert),
F = 1 + (Inc 1) * Cert / 5.
/* */
probtocert (_, 0, 5):!.
probtocert (_, 1, 5):!.
probtocert (Prob, Prior, Cert):
Prob < = Prior,
Cert = 5 * Prob / Prior 5,
!;
Cert = 5 * (Prob Prior) / (1 Prior).
oddstoprob :
oddstoprob (Odds, Prob):
Prob = Odds / (1 + Odds).
, , data - CERTAINTY. certtoprob , :
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certtoprob (Cert, Prior, Value):
Cert < = 0, Value = Prior * (Cert + 5) / 5,
!;
Value = Prior + (1 Prior) * Cert / 5.
