Working on the Structural Components of Evolutionary Approaches
Alexandros Tzanetos
1 a
and Jakub K
˚
udela
2 b
1
J
¨
onk
¨
oping AI Lab (JAIL), J
¨
onk
¨
oping University, Gjuterigatan 5, 553 18 J
¨
onk
¨
oping, Sweden
2
Institute of Automation and Computer Science, Faculty of Mechanical Engineering,
Brno University of Technology, Czech Republic
Keywords:
Evolutionary Computation, Swarm Intelligence, Nature-Inspired Intelligence, Mechanisms, Operators,
Modular Algorithms.
Abstract:
Several researchers have turned their attention to the structural components of Evolutionary Computation-
and Swarm Intelligence-oriented approaches. This direction offers various opportunities, such as developing
automatic design and configuration frameworks and integrating operators and mechanisms addressing known
limitations. This work lists recent operators and discusses promising mechanisms found in existing nature-
inspired approaches. It also discusses how these algorithmic components can be integrated into modular
frameworks and how they can be assessed and benchmarked. The work aims to emphasize the importance of
the research direction about nature-inspired mechanisms and operators in the Evolutionary Computation field.
1 INTRODUCTION
Evolutionary Computation (EC) and Swarm Intelli-
gence (SI) offer a variety of approaches to deal with
high-complexity real-world problems. Yet, not all al-
gorithms from these fields constitute a novel search
strategy. Most of them replicate the ideas introduced
in the established ones, i.e., Particle Swarm Optimiza-
tion (PSO), Ant Colony Optimization (ACO), and Ge-
netic Algorithm (GA) (Tzanetos, 2023).
Moreover, several recently introduced algorithms
contain a center-bias operator, making them unsuit-
able for optimization tasks (Kudela, 2022). Also, sev-
eral other structural biases have been detected in such
algorithms (Vermetten et al., 2022).
However, some algorithms contain promising
mechanisms that can be used to overcome known lim-
itations observed in stochastic nature-inspired algo-
rithms (Thymianis and Tzanetos, 2022). More such
mechanisms can potentially be found in the various
nature-inspired algorithms and benefit other methods.
The current work aims to provide some examples, dis-
cuss their benefits, and pinpoint the promising path
ahead.
Furthermore, novel operators have been proposed
to enhance the algorithms’ performance. Our work
briefly overviews such operators and discusses poten-
a
https://orcid.org/0000-0002-1319-513X
b
https://orcid.org/0000-0002-4372-2105
tial future directions.
Motivated by the recent works pinpointing the
positive effect of improved operators and integrated
mechanisms to nature-inspired approaches (NIAs),
this position paper presents an initial step towards
putting more emphasis on the research direction about
nature-inspired mechanisms and operators in the EC
field. Moreover, it concludes with a non-exhaustive
list of future directions that we believe align with the
topic’s agenda.
The following section provides background on the
heuristic nature of EC techniques. Section 3 lists re-
cent operators and discusses promising mechanisms
found in existing NIAs. Following the example of
(Campelo and Aranha, 2021), we avoid citing the
metaphor-based algorithms in which the mechanisms
were found. Section 4 discusses the opportunity to put
operators and mechanisms into a modular framework
context and assess and benchmark those operators and
mechanisms. Finally, in section 5, we mention some
potential directions in which research can focus.
2 BACKGROUND
The Merriam-Webster dictionary defines the word
“heuristic” as: “involving or serving as an aid to
learning, discovery, or problem-solving by experi-
mental and especially trial-and-error methods”, with
Tzanetos, A. and K˚udela, J.
Working on the Structural Components of Evolutionary Approaches.
DOI: 10.5220/0013083400003837
Paper published under CC license (CC BY-NC-ND 4.0)
In Proceedings of the 16th International Joint Conference on Computational Intelligence (IJCCI 2024), pages 375-382
ISBN: 978-989-758-721-4; ISSN: 2184-3236
Proceedings Copyright © 2024 by SCITEPRESS – Science and Technology Publications, Lda.
375
its etymology being from the German “heuristisch”,
New Latin “heuristicus”, and Greek “heuriskein”
(εὑρίσκειν), meaning “to discover” (or “to happen
upon by chance”).
Many of the EC techniques were conceived by this
trial-and-error approach, with the useful mechanisms
and operators for their applicability “discovered by
chance”. For instance, the original description of Dif-
ferential Evolution (DE) (Storn and Price, 1997) is
given without any theoretical justification and analy-
sis, treating it as a “pure heuristic”. Theoretical works
on the convergence properties of the different opera-
tors in DE, such as the crossover ones in (Zaharie,
2009), came well after it became widely used. Also,
the fact that DE has theoretically supported conver-
gence problems for certain multimodal functions (Hu
et al., 2016) does not bar it from being a successful
and widely used method.
One of the oldest and still widely used stochastic
heuristics is the Simulated Annealing (SA) algorithm
(Kirkpatrick et al., 1983). Interestingly, for SA, the
theoretically justified temperature control schemes
(Hajek, 1988) do not work well in practice (Kochen-
derfer and Wheeler, 2019), and other “heuristically
found” schemes are used instead.
In 1965, the Nelder-Mead (NM) simplex method,
one of the oldest deterministic optimization heuris-
tics, was introduced (Nelder and Mead, 1965). Al-
though the mechanisms of the NM method are not
very complex, it took more than 30 years from its in-
ception before the first notable theoretical work about
its convergence properties was published (Lagarias
et al., 1998). In the paper, the authors prove that
the method converges for strictly convex functions
in 1D but not 2D (by counterexample). The paper
ends with the following statement: Our general con-
clusion about the Nelder-Mead algorithm is that the
main mystery to be solved is not whether it ultimately
converges to a minimizer—for general (nonconvex)
functions, it does not—but rather why it tends to work
so well in practice by producing a rapid initial de-
crease in function values. Further research led to
convergence proofs for 2D, but only for restricted
versions on strictly convex functions (Lagarias et al.,
2012), with the technique of the proof based on treat-
ing the method as a discrete dynamical system. And
new results (such as convergence proofs for dimen-
sions greater than 8) are expected to need techniques
that are not yet developed (Gal
´
antai, 2022).
What these results show is that, in many cases, the
theoretical justifications for EC methods (and heuris-
tics in general) might not lead to useful variants of
such methods (such as in the SA case) or may not be
derivable by currently available techniques (such as in
the NM case). It is not hard to imagine a simple mech-
anism, with inner workings akin to the 3n + 1 prob-
lem, that will elude theoretical analysis (Guy, 2004).
Nevertheless, there has been undeniable progress
in the theoretical works, mainly focusing on dis-
crete settings with “simpler” EC methods for which
tools such as drift analyses can be used (Doerr and
Neumann, 2021). For the continuous setting and
the “more involved” techniques, experimental meth-
ods for runtime analysis are available (Huang et al.,
2019).
3 NATURE-INSPIRED
MECHANISMS AND
OPERATORS
The difference between a mechanism and an operator
may not be obvious. Both terms appear in the litera-
ture, usually to describe algorithmic components.
A suitable definition for the word mechanism,
given by (Ross et al., 2022), states that it is a process
or system that is used to produce a particular result”.
No standard definition exists for the word opera-
tor within the sciences concept. In mathematics, an
operator refers to a mapping or function that acts on
elements of a space to produce elements of another
space. In computer programming, operators are con-
structs defined within programming languages that
behave like functions. A common ground in the above
definitions is the concept of a function. However,
we cannot claim that an operator is a function. The
Merriam-Webster dictionary definition seems more
suitable: a single step performed by a computer in
the execution of a program”.
A more open-ended definition for Evolutionary
Operators is a total parameter-alteration operation
on the parameterization of generalized coordinates of
a system along its dynamic path given by (
¨
Oz, 2005),
where the theoretical aspects of variational and ex-
tremum principle derived from various sciences are
studied.
To distinguish the two concepts within the EC
field, we can say that a mechanism is a process ap-
plied to the whole population of candidate solutions.
In contrast, an operator is a single-step operation ap-
plied to some or selected candidate solutions.
3.1 Traditional Operators
The original idea of operators comes from the evo-
lutionary operations included in the Darwinian-like
evolutionary process in the first evolutionary ap-
ECTA 2024 - 16th International Conference on Evolutionary Computation Theory and Applications
376
proaches (De Jong, 2012). These operations corre-
spond to (a) asexual reproduction, i.e., the mutation
operator, (b) sexual reproduction, i.e., the crossover
operator, and (c) natural selection, i.e., the selection
operator.
The mutation and crossover operators, also called
reproductive operators, create a mix of local and
global search. The selection operator aims to balance
exploration and exploitation effectively.
The above evolutionary operators are very simple
operations. Indeed, they involve combining elements
of more than one parent solution, altering some of
the current solution’s elements, and selecting which
candidate solutions will be passed to the next genera-
tion. The rationale behind these operators is to tackle
pseudo-Boolean optimization problems:
f : {0,1}
d
R (1)
which consisted of d binary decision variables. The
binary value solution space makes the above evolu-
tionary operators proper for searching different com-
binations of a given solution.
3.2 Recently Presented Operators
Several researchers have developed operators that
overcome the limitations of the original ones. Such
limitations are infeasible solutions created by the
reproduction operators, low-quality solutions trans-
ferred to the new population due to a poor selection
process, and premature convergence due to low diver-
sity in the population. Below, we present an example
for each evolutionary operator, i.e., crossover, muta-
tion, selection, and one example of a population man-
agement operator.
(Sharma et al., 2021) introduced the idea of en-
sembled crossover for evolutionary algorithms, con-
sidering that different crossovers are suitable for dif-
ferent optimization problems. As a result, the authors
mentioned that the ensembled crossover is more ro-
bust on various optimization problems with different
characteristics such as variable dependency or multi-
modality. The difference from the original crossover
operator is that the crossover probability is drawn
from various distributions, e.g., uniform, epsilon, ex-
ponential, etc. Each distribution has the same prob-
ability of being selected at the beginning. The algo-
rithm updates the probabilities based on the propor-
tion of survivors to the created offspring members.
The Neighbor-Hop mutation is a mutation oper-
ator where a gene is replaced randomly by one of
its neighbor nodes in a graph (Chawla and Cheney,
2023). The authors applied their Neighbor-Hop mu-
tation-based GA to the Influence Maximization Prob-
lem, i.e., finding the set of k most influential nodes in
a social network. The solution representation of the
GA for that problem is a sequence of k nodes from the
given graph. The introduced mutation operator is suit-
able for the application since it explores different seed
node permutations without causing any infeasible so-
lutions. That would not be the case if the problem was
the Travelling Salesman Problem. The Neighbor-Hop
mutation is an example of an operator introduced for
a specific problem type.
The fitness-distance balance is a recent selection
operator introduced by (Kahraman et al., 2020) that
enables the proper determination of candidates with
the highest potential to improve the search process.
First, the distance between the candidate and the best
solution is calculated and stored in a distance vector.
Then, the distance vector and the fitness vector are
normalized. The fitness vector contains the fitness
values of the candidate solutions in the same order
as the distance vector. The Fitness-Distance Balance
(FDB) score is calculated as:
S
FDB
= w · norm
F
i
+ (1 w) · norm
D
i
(2)
where norm
D
i
is the normalized distance value of the
i-th candidate solution and norm
F
i
is the correspond-
ing candidate solution’s normalized fitness value. The
weight coefficient w (0,1) determines the impact of
fitness and distance values.
An alternative way to calculate the FDB score is:
S
FDB
= norm
F
i
· norm
D
i
(3)
Another category of operators consists of the ones
considering population diversity. They monitor the
population diversity and perform changes, e.g., in the
algorithm’s selection operator (Strze
˙
zek et al., 2015),
or in the population size.
(Morales-Castaneda et al., 2022) introduced a new
set of evolutionary operators that falls within the sec-
ond case. These operators permit the management
of the population size to avoid search stagnation and
allow more efficient exploitation. To prevent search
stagnation, the Stagnation Correction Operator in-
troduces new candidate solutions using a dimension-
wise diversity measurement metric (Hussain et al.,
2019). To improve the exploitation efficiency, the
Exploitation Efficiency Operator compares the cur-
rent diversity with the maximum diversity previously
found, and based on a predefined diversity percent-
age, the population is reduced. In their work, the au-
thors use 10% as the diversity percentage that indi-
cates the algorithm is entering its exploitation phase,
and they reduce the population by 1/5. For a diversity
percentage equal to 2%, indicating that the exploita-
tion phase is deep in progress, the population is more
significantly reduced by 3/5.
Working on the Structural Components of Evolutionary Approaches
377
Diversity-based operators have shown promising
results (Cheng et al., 2021; Wang et al., 2023). Work
on such operators can be extended by considering
other diversity measures, such as the attraction basins-
based measure introduced by (Jerebic et al., 2021).
3.3 Promising Mechanisms
3.3.1 Cyclic Universe Theory
The cyclic universe theory (Steinhardt and Turok,
2002) inspired the Big Bang - Big Crunch (BB-BC)
algorithm. According to this theory, the universe un-
dergoes endless cycles of expansion and cooling, each
beginning with a “Big Bang” and ending in a “Big
Crunch”. The Big Bang phase is the expansion phase,
whereas, in the Big Crunch phase, the gravitational at-
traction of matter causes the universe to collapse back
in. The two phases described above comprise the BB-
BC algorithm.
During the Big Bang phase, the candidate solu-
tions are randomly placed in the solution space using
the following formula:
x
d
new
= x
d
c
+
l
d
× rand
k
(4)
where l
d
is the upper limit for the d-th dimension,
rand is a random number uniformly distributed and k
is the current iteration of the algorithm. This equation
considers the ”center of mass”
x
c
= [x
1
c
,x
2
c
,..., x
ND
c
],
where ND is the number of the problem’s dimensions.
In the Big Crunch phase, the candidate solutions
converge to a single point, i.e., the center of mass,
calculated as:
x
d
c
=
N
i=1
1
/f
i
x
d
i
N
i=1
1
/f
i
(5)
where x
d
i
denotes the position of the i-th candidate so-
lution in the d-th dimension, f
i
denotes the value of
the i-th candidate solution in the fitness function and
N is the population size.
The BB-BC algorithm iterates between these two
phases. The population of the previous generation is
used to calculate the center of mass using eq. 5 and
then, new candidate solutions are generated around
this center of mass using eq. 4.
This cyclic universe process is the equivalent of
killing the population in each generation and gener-
ating a new one. The advantage of this concept is
that the center of mass contains information from all
candidate solutions. In EC, and especially in evolu-
tionary algorithms, the new population is randomly
created. On the other hand, the continuous iteration
between ”killing the population” and ”creating a new
one” has the drawback of not letting any candidate
solutions evolve.
3.3.2 Mine Explosion Dynamics
The Mine Blast Algorithm (MBA) contains a mech-
anism inspired by the mine explosion dynamics.
Specifically, considering that
X = {X
1
,X
2
,..., X
m
}
represents the location of a mine and that N
s
shrap-
nel pieces are produced by the mine bomb explosion
causing another mine to explode at location X
e(n+1)
,
calculated as:
X
e(n+1)
= d
n+1
× cos θ (6)
where θ is the angle of the shrapnel pieces, which is
a constant value and is calculated using θ = 360/N
s
and d
n+1
is the distance of the thrown shrapnel pieces,
calculated as:
d
n+1
= d
n
· |randn|
2
(7)
where randn is a normally distributed random num-
ber, and n is a number defined as n 1,2,...,N
s
.
The above formulation describes the algorithm’s
exploration phase. Additionally, another operator is
set for the algorithm’s exploitation phase. In that case,
the shrapnel’s position is calculated as:
X
n+1
= X
e(n+1)
+ exp(
r
m
n+1
d
n+1
) · X
n
(8)
where d
n+1
and m
n+1
denote the distance and the di-
rection (slope) of the thrown shrapnel pieces in each
iteration, respectively. Also, X
e(n+1)
denotes the lo-
cation of exploding mine bomb collided by shrapnel,
given by:
X
e(n+1)
= d
n
· rand · cos θ (9)
where rand is a uniformly distributed random number
and θ is the angle of the shrapnel pieces which is a
constant value and is calculated using θ = 360/N
s
,
where N
s
denotes the number of shrapnel pieces.
The distance d
n+1
of the thrown shrapnel pieces is
calculated as:
d
n+1
=
q
(X
n+1
X
n
)
2
+ (F
n+1
F
n
)
2
(10)
where F denotes the quality of each particle.
The direction m
n+1
of the thrown shrapnel pieces
is given by:
m
n+1
=
F
n+1
F
n
X
n+1
X
n
(11)
3.3.3 Negatively Charged Stepped Leader
The Lightning Search Algorithm (LSA)’s central con-
cept is inspired by the negatively charged stepped
leader moving from a cloud to the earth (Dul’zon
et al., 1999), i.e., the phenomenon of separations of
the luminous channel (i.e., projectile) that propagates
ECTA 2024 - 16th International Conference on Evolutionary Computation Theory and Applications
378
through ionized paths, creating this tree structure of
lightning.
Three projectile types are considered in LSA, i.e.,
transition, space, and lead. The transition projectiles
are used to create the first-step leader population N,
the space projectiles are considered to reach the best
leader position, and the lead projectiles represent the
best position among the N step leaders.
Transition projectiles create a random population
of N first-step leader uniformly distributed. They are
also used to create new projectiles when necessary.
The space projectile p
S
i
is calculated as:
p
S
i,new
= p
S
i
± exprand(µ
i
) (12)
where exprand(µ
i
) denotes an exponentially dis-
tributed random number. The operator ± in eq. 12
denotes that exprand(µ
i
) should be subtracted if p
i
is
negative, but it should be added if p
i
is positive. This
operation is used to avoid any change of direction in
the solution space since exprand(µ
i
) returns only pos-
itive values.
This step separates the projectile into stepped
leaders. If p
S
i,new
provides a good solution, the cor-
responding stepped leader will be further separated.
Otherwise, it will remain unchanged. If p
S
i,new
extends
all stepped leaders beyond the recent most extended
leader, it becomes the lead projectile.
Finally, the lead projectile p
L
i
is calculated as:
p
L
i,new
= p
L
i
± normrand(µ
L
,σ
L
) (13)
where normrand(µ
L
,σ
L
) denotes a normally dis-
tributed random number. This step is performed for
exploitation. As for the space projectile, if p
L
i,new
pro-
vides a better solution, it will be extended until no
better solution is found.
3.3.4 Spiral Dynamics
The Spiral Dynamic Algorithm (SDA) introduced a
concept inspired by spiral phenomena observed in na-
ture, such as galaxies, hurricanes, and tornadoes. The
concept is a spiral model that provides dynamic step
size for each candidate solution when searching the
solution space. The step size is larger at the begin-
ning to enable exploration and gets smaller during the
algorithm to focus on exploitation. The step size is
defined based on a spiral radius r and the spiral rota-
tion angle θ, which are open parameters.
A similar concept was introduced in Hurricane-
based Optimization Algorithm (HOA) where solu-
tions are divided into j = d 1 groups based on the
problem’s dimensions d. The candidate solution per-
forms a rotation in each dimension defined by the
group k = i mod (d 1) it belongs to. In this model,
more parameters are used but based on the same con-
cept, i.e., radial and angular coordinates.
The spiral movement concept also inspired the
Circular Water Wave (CWW) algorithm. The step
size is calculated using a simpler equation compared
to SDA and HOA. The spiral model used in this algo-
rithm considers a radius r
i
, a random value w that is
used as a coefficient, and the wave number c
j
, where
1 j m, and m denotes the maximum number of
wave circles, i.e., iterations of the algorithm.
Even though different models are introduced in
the three algorithms mentioned above, the mechanism
is the same. That is, a radius and a rotation angle de-
fine the step sizes, which are performed towards an
“eye”, i.e., a central point.
3.4 Discussion
As pointed out by (Tzanetos, 2023), only the cyclic
universe mechanism seems consistent with the phe-
nomenon inspired from. Also, the spiral dynamics
mechanism utilizes the mathematical background of
spiral dynamics. The rest of the mechanisms men-
tioned above are simplifications of a phenomenon.
Nevertheless, the mechanisms mentioned in the
current work can be useful components for modi-
fied or improved versions of established approaches.
(Thymianis and Tzanetos, 2022) showed that the inte-
gration of the cyclic universe mechanism and the mine
explosion mechanism improve the exploration ability
of fast converging approaches, such as PSO.
We believe that a similar value can be found in
the rest of the above mechanisms. The Negatively
Charged Stepped Leader seems a promising explo-
ration strategy (Tzanetos, 2023), too. Moreover, it
could be combined with a population management
operator that eliminates non-promising solutions be-
fore further separation into stepped leaders occurs.
The spiral dynamics mechanism seems a promising
exploitation strategy, i.e., a local search component to
intensify the search around local optima.
Furthermore, other promising mechanisms can be
found in the literature. A crucial question is how we
can identify such mechanisms. This is not a trivial
task since using metaphor-based language does not
enable researchers to fully comprehend a method’s
mathematical background (Aranha et al., 2022).
While mechanisms constitute different stepwise
processes, most of the existing operators are vari-
ations of the evolutionary operators, i.e., crossover,
mutation, selection, or population management tech-
niques. Research on new operators is more estab-
lished than that on mechanisms. Apart from the nu-
merous papers found in the literature, relevant work-
Working on the Structural Components of Evolutionary Approaches
379
shops exist.
For example, dedicated workshops enable re-
searchers to investigate the selection aspect in EC.
The most recent such workshops are the Workshop on
Selection
1
and the Workshop on Search and Selection
in Continuous Domains
2
.
4 MODULAR FRAMEWORKS
Identifying the individual mechanisms and operators
of EC methods enables the creation and investigation
of modular frameworks, which facilitate the (either
manual or automatic) design of high-performance
implementations of EC methods (Camacho-Villal
´
on
et al., 2023). Among the first modular frameworks
was ParadisEO (Cahon et al., 2004), which contains
four main modules/objects for the composition of EC
methods: estimation of distribution objects (for esti-
mation of distribution methods), evolving objects (for
population-based methods), moving objects (for local
search methods), and multiobjective evolving objects
(for multiobjective methods).
Recently, there has been an increased interest in
creating modular frameworks around established EC
methods, with a focus on the inclusion of the most
widely used/representative mechanisms and operators
for that method. The most notable ones are the modu-
lar frameworks for ACO (L
´
opez-Ib
´
a
˜
nez et al., 2018),
PSO (Camacho-Villal
´
on et al., 2021), Covariance ma-
trix adaptation evolution strategy (CMAES) (de No-
bel et al., 2021), and DE (Vermetten et al., 2023).
There is a current debate about the different mer-
its of manual and automatic design of EC methods
using modular frameworks (Camacho-Villal
´
on et al.,
2023). The manual approaches rely heavily on an
“expert designer” who understands not only the in-
ner workings of the algorithms but also the problem
to which they are applied. On the other hand, the au-
tomatic design of EC methods usually utilizes con-
figuration tools such as SMAC (Hutter et al., 2011)
or irace (L
´
opez-Ib
´
a
˜
nez et al., 2016). However, these
tools still require some input from the user, such as
selecting a set of relevant operators and mechanisms.
For white-box problems, where the mathematical de-
scription of the problem to be solved is known, the
possibility of using a pre-processing tool that scans
the problem description and returns a reasonable set
of possible operators for the automatic selection tool
(hence requiring even less expertise from the user) is
1
https://www.yorku.ca/sychen/research/workshops/
CEC2021 Selection Workshop.html
2
https://www.yorku.ca/sychen/research/workshops/
CEC2024 Search and Selection Workshop.html
still a not very well explored area. Recent results of
using the various automatic configuration tools in dis-
crete (Aziz-Alaoui et al., 2021; Ye et al., 2022) are
very promising.
Another relatively under-explored line of research
lies in assessing “usefulness” and benchmarking the
individual modules and their combinations. In (Niko-
likj et al., 2024), this assessment was performed with
the utilization of the functional ANOVA (f-ANOVA)
framework (Hutter et al., 2014). Although the exper-
iments were relatively large-scale in terms of com-
pared variants (324 CMAES and 576 DE variants),
they were only small-scale in terms of dimensions
(only dimensions 5 and 30 were investigated) and
computational budgets (100 ×ND - 1500 × ND func-
tion calls). Another approach utilizing the Search Tra-
jectory Networks, population diversity, and anytime
hypervolume values for the assessment of the impact
of the modules in the multiobjective setting was de-
scribed in (Lavinas et al., 2024). To assess budget-
dependent mechanisms/operators (such as linear pop-
ulation reduction schemes), the standard anytime per-
formance measures should be used cautiously (Tu
ˇ
sar
et al., 2017).
5 CONCLUSIONS AND FUTURE
DIRECTIONS
This position paper presents an initial step towards
putting more emphasis on the research direction about
nature-inspired mechanisms and operators in the EC
field. We believe this direction offers various oppor-
tunities, such as extending the automatic design and
configuration frameworks by including proper mech-
anisms and operators, integrating existing operators
and mechanisms into established algorithms to ad-
dress their limitations, developing new proper oper-
ators, identifying other promising mechanisms, and
investigating performance measures to assess the ef-
fect of these algorithmic components.
Recent works pinpointed the positive effect of im-
proved operators and integrated mechanisms to NIAs.
Along those lines, we listed four recently developed
operators and four promising mechanisms found in
existing NIAs. We discussed the benefits of those se-
lected operators and mechanisms. We also discussed
how these algorithmic components can be integrated
into modular frameworks and how they can be as-
sessed and benchmarked.
As mentioned above, we see this work as a starting
point in the research agenda on nature-inspired mech-
anisms and operators. Therefore, we list a few future
directions below that we believe align with the topic’s
ECTA 2024 - 16th International Conference on Evolutionary Computation Theory and Applications
380
agenda. We do not claim that these directions are ex-
haustive. We invite interested researchers to extend
this agenda.
Following the recent progress in the theoretical
background of evolutionary approaches, the mathe-
matical and theoretical analysis of mechanisms and
operators included in EC and SI algorithms could pro-
vide more insight into these algorithmic components
and their effects.
Identifying and implementing other mechanisms
being part of existing EC and SI algorithms will ex-
tend the options of algorithmic components. Iden-
tifying several mechanisms with various characteris-
tics enables selecting the most suitable to address an
algorithm’s known limitation. Also, EC researchers
could focus on developing improved operators that
overcome the defects of the existing ones.
Furthermore, a smooth integration between differ-
ent automatic operator selection tools with the exist-
ing modular frameworks could help identify the use-
fulness of both the individual mechanisms and opera-
tors and their interplay. The methodologies for prop-
erly assessing and benchmarking these components
are currently being developed and tested, leaving am-
ple room for extensions and improvements.
Last but not least, applying the modified algo-
rithms to real-world problems is equally important to
the theoretical work. After all, the ultimate goal of
developing an algorithm is to solve a problem. Thus,
investigating the modified algorithms’ performance
on real-world problems will reveal which components
may be more suitable for specific problem types.
ACKNOWLEDGEMENTS
The research work of J. K
˚
udela was supported by a
grant (No. FSI-S-23-8394) from the IGA Brno Uni-
versity of Technology and by the project (no. 24-
12474S) funded by the Czech Science Foundation.
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