Beyond clicks dwell time for personalization, Recsys'14の 論文紹介，http://www.hongliangjie.com/publications/recsys2014.pdf

14. (t3 t2) + (t5 t4)

15. i Commentt1 t2 t3 t4 t5
(t2 t1) + (t5 t4)
(t4 t1)
i
Click j k niClick Click Click
i

23. xq,d
xq,d = g(q, d)
l
yq,d

26. yd,u 2

28. f(x)
ft(x) = Tt(x; ⇥) +
TX
t=1
tTt(x; ⇥t)
L(yi, fT (xi))
Tt(x; ⇥t)
ˆ⇥ = arg min
NX
i
wi( Git tTt(xi; ⇥))
t = arg min
NX
i
L(yi, ft 1(xi) + T(xi, ✓))

30. DCGk =
kX
i=1
2reli 1
log2(i + 1)
NDCGk =
DCGk
IDCGk

31. MAP =
PU
u=1 AveP(u)
U
AveP(u) =
PN
k=1(P(k) ⇥ rel(k))
# of relevant articles for user u

35. I =
0
B
B
B
B
B
B
@
r11 r12 ... r1j ... r1N
r21 r22 ... r2j ... r2N
... ...
ri1 ri2 ... rij ... riN
... ...
rM1 rM2 ... rMj ... rMN
1
C
C
C
C
C
C
A
arg min
U,V
MX
i=1
X
ri,j <ri,k
Ui(Vj Vk)T
+ (|U|2 + |V |2)
I = U ⇥ V T
ˆrij = Ui ⇥ V T
j
2
2