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Table 1. Simulation parameters
# of jobs ( N )
10000
# of workers ( W )
100
acceptable error rate ( acc )
0.01 / 0.001
redundancy ( M )
1 10
sabotage model
predefined colluding
faulty fraction ( f )
0 ∼ f max (0.35)
sabotage rate ( s )
0 1
colluding rate ( c )
0 1
defection model
random defection
defection rate ( p d )
0 0.8
spot-check rate ( q )
0.1 / 0.2
saboteur knows when it is caught by spot-checking in a system without blacklisting [23,
40]. After having been caught, the saboteur immediately rejoins to the system and returns
incorrect results as a new worker.
3.2.2. M -first Voting vs. M -Majority Voting
First, We provide comprehensive comparison study of two basic voting methods, M -first
voting and M -majority voting, to reveal their sabotage tolerance performance and draw-
backs.
0.02
500
M=1
M=2,Majority
M=3,Major i t y
M=2,M- f irst
M = 3,M-first
M=1
M=2,Majority
M=3,Majority
M=2,M-first
M=3,M-first
ε acc
450
0.015
400
350
0.01
300
250
200
0.005
150
100
0
0
0.2
0.4
0.6
0.8
1
0
0.2
0.4
0.6
0.8
1
s
s
(b) Computation time T
(a) Error-rate
Figure 5. M -first voting vs. M -majority voting for sabotage rate s ( acc =0.01 , f =0.35 ,
c =0.1 , p d =0 , random scheduling).
Sabotage rate s and fraction f Fig.5(a) and Fig.6(a) show error rate of each voting
method for sabotage rate s and fraction f , respectively.
These figures show that larger
 
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