ֶशɿLearning To Rank
ΫΤϦʹର͢Δؔ࿈Λࢉग़͢ΔؔΛrankingͱֶͯ͠श͢Δ
8
pairwise preference approach
ΫΤϦ q ɼؔ͋ΔΞΠςϜ d+ ɼؔͳ͍ΞΠςϜ d- ʹ͍ͭͯɼɹ
ҎԼͷΑ͏ͳؔ fq
Λֶश͢Δ
fq(d+) > fq(d )
min
w
m
X
i=1
max(1 yi
h
xi, w
i
, 0) + 1
||
w
||1
+ 2
||
w
||2
RankingSVMͱͯ͠ɼҎԼͷ࠷খԽΛղ͘
(
xi, yi) =
(
d
+
d ,
+1
d d
+
,
1
a well-ordered pair
a poorly ordered pair