Time-Efficient Allocation Mechanisms for Crowdsensing Tasks with Precedence Constraints

. 2019 May 29;19(11):2456. doi: 10.3390/s19112456

Algorithm 3 Allocation priority sequence construction

Require:
the task set

T

, the final task set

F

,
the refresh task sequence

R

;
Ensure:
the allocation priority sequence

{f_{j}}_{t_{j} \in T}

;

1:
for $k = 1$ to $max {L_{j}}_{t_{j} \in T}$ do
2:
for each task in $T$ do
3:
if $L_{j} = k$ then
4:
Set $c_{j}^{t}$ is the task with the maximum expected finishing time among all the tasks in $C_{j}$ .
5:
Compute the expected finishing time $h_{j}^{e}$ ;
6:
Set $l = 1$ ;
7:
while $T \neq ϕ$ do
8:
Find the final task $t_{q} \in F$ with maximum expected finishing time;
9:
Construct the critical task sequence of task $t_{q}$ ;
10:
Set $f_{p} = l$ ;
11:
Find the task $t_{p}$ with the lowest level in the critical task sequence of task $t_{q}$ ;
12:
Delete $t_{p}$ from $T$ ;
13:
if $t_{p} \in F$ then
14:
Delete $t_{p}$ from $F$ ;
15:
Gather all the rest tasks that have priority relationship with $t_{p}$ in the sequence $R$ ;
16:
for each task $t_{j}$ in $R$ do
17:
Set $c_{j}^{t}$ is the task with the maximum expected finishing time among all the tasks in $C_{j}$ .
18:
Compute the expected finishing time $h_{j}^{e}$ ;
19:
Add all the rest tasks that have priority relationship with $t_{j}$ to the back of sequence $R$ ;
20:
Set $l = l + 1$ ;