PBIL
1. Initialize a probability vector p = {p
1
, p
2
, ..., p
n
} with
each p
i
= 0.5. Here, p
i
represents the probability of x
i
taking value 1 in the solution
2. Generate a population P consisting of M solutions by
sampling probabilities in p
3. Select set D from P consisting of N best solutions
4. Estimate probabilities of x
i
= 1 , for each x
i
, as
5. Update each p
i
in p using p
i
= p
i
+ λ(p(x
i
= 1) − p
i
).
Here, 0 ≤ λ ≤ 1 is a parameter of the algorithm known
as the learning rate
6. Go to step 2 until the maximum number of
generations (r) is reached
DEUMd
1. Generate a population, P, consisting of M solutions
2. Select a set D from P consisting of N best solutions,
where N ≤ M.
3. For each solution, x, in D, build a linear equation
with the following form
η(F(x)) = α
0
+ α
1
x
1
+ α
2
x
2
+ ... + α
n
x
n
Where, function η(F(x)) < 0 is set to −ln(F(x)), for which
F(x), the fitness of the solution x, should be ≥ 1,
α = {α
0
+ α
1
+ α
2
+ ... + α
n
} are equation parameters, 0
values in binary variable x
i
are replaced with -1 for
creating linear equations.
4. Solve the build system of N equations to estimate α
5. Use α to estimate the distribution
where
Here, β (inverse temperature coefficient) is set to β=g×
τ; g is the current iteration of the algorithm and τ is the
parameter known as the cooling rate.
6. Generate M new solution by sampling p(x) to
replace P and go to step 2 until the maximum number
of generations (r) is reached.
SA
1. Randomly generate a solution x = {x
1
, x
2
, ..., x
n
}
2. For i = 1 to r do
a. Randomly mutate a variable in x to get x’
b. Set Δf = f(x’) − f(x)
c. Set x = x’ with probability
Where temperature coefficient T was set to T = 1/i×τ, i is
the current iteration, and τ is the parameter of the algorithm
called the cooling rate.
3. Terminate with answer x.
6 EXPERIMENTS AND RESULTS
In this paper, we used five different sample areas
from the data provided by our telecom partner for
testing the performance of the algorithms. These
areas represent a typical network size, in which our
partner is required to deploy smart meters with
different settings for feeders, meters and RSSI
distances. We denote them as Area1, Area2, Area3,
Area4 and Area5. The number of feeders were 408,
373, 519, 445 and 159, respectively for areas 1 to 5.
Similarly, the number of meters were 1826, 1275,
1485, 1133, 688 for areas 1 to 5 respectively. Also,
the maximum RSSI allowed (
) was set to -85
dbm, which meant any connection of a meter to
feeder with RSSI over -85 was counted as violation
and added to the link cost in equation 1. The value of
up to -85 was given the equal preference and therefore
had a 0 cost. The value for the total link cost, hence,
would be 0, if no link encoded in the solution is over
the RSSI limit of -85 dbm.
In addition, each algorithm has different set of
parameters that needs to be fine-tuned to obtain the
best results. We perform empirical analytics to find
the parameters for each algorithm where each
algorithm was run for 10 times with multiple settings
for each of the parameters, and those parameters that
provide the best average results were used as the
output of the algorithm.
Population size parameter (ps) for a population-
based algorithm such as GA, PBIL, and DEUMd,
ranged from 300 to 1000. The maximum generation
(mg) ranged from 500 to 1000. In addition, the elitism
(es) of 0 or 2 was used, i.e., either none or the best
two solutions from the previous generation were
copied to the next generation.
For the GA, four selection operators (so) were
tested, which included roulette wheel (rw),
tournament (tm), and two types of truncation
selection: one with selection size set to 0.5 of the
population size (tr0.5) and another with 0.3 (tr0.3)
(Bäck et el, 1997). The crossover operators (co) tested
were “simple one point” (op) and “uniform” (un)
crossovers with the probability of bit swapping set to
0.5 (un0.5). The mutation operator (mo) was set to
one-bit flip mutation (ob) [17]. In addition, the tested
crossover probabilities (cp) were 0.6 and 0.8, and the
mutation probabilities (mp) tested were 0.0001,
0.001, and 0.01, respectively.
For the PBIL, a truncation selection (Bäck et el,
1997) was used with 3 different settings for the size
of the selected population for recombination
operations (ss), which were 0.3, 0.5, 0.7 of the
population size. When the selection size is set to a
large value, the convergence of PBIL becomes slower
since the diversity is maintained for a longer period.
SIMULTECH 2024 - 14th International Conference on Simulation and Modeling Methodologies, Technologies and Applications
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