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Ranked list of the instances at time t and t + 1
a 2 , a 1 , c 1 , a 3 , a 4 , d 3 , c 4 , c 2 , d 2 , b 1 , b 4 , b 2 , d 1 , d 4 , c 3 , b 3
(a) The expanded sorted list.
Instance Counter=[A,B,C,D]
a 2 [0, 0, 0, 0]
a 1 [1, 0, 0, 0]
c 1 [1, 0, 1, 0]
a 3 [1, 0, 1, 0]
a 4 [0, 0, 1, 0]
d 3 [0, 0, 1, 0]
c 4 [0, 0, 0, 0]
c 2 [0, 0, 0, 0]
d 2 [0, 0, 0, 0]
b 1 [0, 1, 0, 0]
b 4 [0, 0, 0, 0]
b 2 [0, 0, 0, 0]
d 1 [0, 0, 0, 1]
d 4 [0, 0, 0, 0]
c 3 [0, 0, 0, 0]
b 3 [0, 0, 0, 0]
(b) The bitmap counters.
Fig. 6.1 The sorted lists of instances in SW
(
t
1
)
and SW
(
t
)
.
ranking order. If an expired instance or a new instance o
O i is met, we set c
[
i
]=
c
[
i
]
1.
For an instance o
O i in the expanded list such that o is in both W t
and W t + 1 ,if
[
]
all the bitmap counters, except for c
i
, are 0 right before o is read, then, for every
instance o
, o
(
=
)
o in the expanded sorted list, one of the following
three cases may happen: (1) o appears in both W t
O j
i
j
and W t + 1 ; (2) o =
O j [
t
ω +
1
]
(i.e., o appears in W t
o ; or (3) o =
O j [
only) and the new instance O j
[
t
+
1
]
t
+
1
]
(i.e., appears in W t + 1
only) and the expired instance O j [
t
ω +
1
]
o . In all the
three cases, DS t
and DS t + 1
(
o
)
(
o
)
are compatible if o does not arrive at time t
+
1.
1, then we check the left and the right neighbors of o in
the expanded sorted list. If one of them o is from the same stream as o , then DS
If o arrives at time t
+
(
o
)
o )
and DS
are compatible.
We conduct Poisson recurrence for only instances which are in W t + 1
(
and do
not have a compatible dominance set. Otherwise, they are expired instances or their
top- k probabilities can be obtained from the compatible dominant sets immediately.
After one scan of the expanded sorted list, we identify all compatible dominant sets
and also compute the top- k probabilities. Then, we remove from the expanded sorted
list those expired instances. The current sliding window is processed. We are ready
to slide the window to the next time instant
( O )
(
t
+
2
)
.
 
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