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. 2024 Feb 23;9(3):137. doi: 10.3390/biomimetics9030137

Botox Optimization Algorithm: A New Human-Based Metaheuristic Algorithm for Solving Optimization Problems

Marie Hubálovská 1, Štěpán Hubálovský 1, Pavel Trojovský 1,*
Editors: Heming Jia1, Laith Abualigah1, Xuewen Xia1
PMCID: PMC10967787  PMID: 38534822

Abstract

This paper introduces the Botox Optimization Algorithm (BOA), a novel metaheuristic inspired by the Botox operation mechanism. The algorithm is designed to address optimization problems, utilizing a human-based approach. Taking cues from Botox procedures, where defects are targeted and treated to enhance beauty, the BOA is formulated and mathematically modeled. Evaluation on the CEC 2017 test suite showcases the BOA’s ability to balance exploration and exploitation, delivering competitive solutions. Comparative analysis against twelve well-known metaheuristic algorithms demonstrates the BOA’s superior performance across various benchmark functions, with statistically significant advantages. Moreover, application to constrained optimization problems from the CEC 2011 test suite highlights the BOA’s effectiveness in real-world optimization tasks.

Keywords: optimization, human-inspired, metaheuristic, Botox, exploration, exploitation

1. Introduction

Optimization problems, characterized by multiple feasible solutions, involve finding the best solution among them. Mathematically, these problems consist of decision variables, constraints, and an objective function. The optimization process aims to determine optimal values for decision variables, adhering to constraints while optimizing the objective function. Numerous real-world applications in science, engineering, industry, and technology necessitate effective optimization techniques. Two main approaches, deterministic and stochastic, address these challenges. Deterministic approaches, including gradient-based and non-gradient-based methods, excel in handling simpler problems but face limitations in complexity and local optima traps. To address complex, nonlinear, and high-dimensional challenges, researchers have developed stochastic approaches, acknowledging the limitations of deterministic methods in practical optimization scenarios [1,2,3,4,5,6].

Metaheuristic algorithms represent a widely employed stochastic approach for effective optimization problem-solving. Leveraging random search, random operators, and trial-and-error processes, these algorithms yield suitable solutions. The optimization process initiates with the random generation of candidate solutions, progressively enhancing them through iterations. The final output is the best-improved candidate solution. While the inherent randomness poses challenges in guaranteeing a global optimal solution, solutions obtained from metaheuristic algorithms are considered to be quasi-optimal due to their proximity to the global optimum. The pursuit of more effective quasi-optimal solutions, closely aligning with the global optimum, drives the development of various metaheuristic algorithms [7,8].

For metaheuristic algorithms to effectively address optimization problems, they must conduct thorough searches at both the global and local levels within the problem-solving space. Global search, aligned with exploration, denotes the algorithm’s proficiency in extensively exploring the problem-solving space to identify the region containing the primary optimum and avoid local optima. Local search, associated with exploitation, illustrates the algorithm’s ability to closely investigate promising solutions, aiming for convergence to the global optimal solution. The success of a metaheuristic algorithm is contingent on striking a balance between exploration and exploitation throughout the search process [9].

The central research inquiry revolves around whether, given the multitude of existing metaheuristic algorithms, there remains a necessity to develop novel ones. In addressing this query, the No Free Lunch (NFL) principle [10] asserts that a metaheuristic algorithm’s success in optimizing a specific set of problems does not guarantee comparable performance across all optimization tasks. The NFL theorem posits that no single metaheuristic algorithm can be deemed the optimal solution for all optimization challenges. It highlights the unpredictability of an algorithm’s success or failure in addressing different optimization problems, emphasizing that a method that is successful in converging to the global optimum for one problem may encounter difficulties, such as local optima entrapment, when applied to another problem. Consequently, the NFL theorem discourages assumptions about the universal effectiveness of a metaheuristic algorithm and encourages ongoing exploration and introduction of new algorithms to enhance solutions for diverse optimization problems.

This paper brings innovation and novelty to the forefront by introducing the Botox Optimization Algorithm (BOA), a novel metaheuristic approach for solving optimization problems. The key contributions of this paper encompass the following:

  • Introducing the BOA involves emulating the Botox injection process, drawing inspiration from enhancing facial beauty by addressing defects in specific facial areas.

  • BOA theory is described and then mathematically modeled.

  • The BOA’s performance is rigorously assessed using the CEC 2017 test suite, showcasing its efficacy in solving optimization problems.

  • The algorithm’s robustness is further tested in handling real-world applications, particularly in optimizing twenty-two constrained problems from the CEC 2011 test suite.

  • The BOA’s performance is objectively compared with twelve established metaheuristic algorithms, establishing its competitive edge and effectiveness.

This paper follows a structured outline: Section 2 encompasses a comprehensive literature review. Section 3 introduces and models the Botox Optimization Algorithm. Section 4 presents simulation studies and results. The efficacy of the BOA in real-world applications is explored in Section 5. The paper concludes with Section 6, offering conclusions and suggestions for future research.

2. Literature Review

Metaheuristic algorithms draw inspiration from diverse sources, such as natural phenomena, living organisms’ lifestyles, the laws of physics, biology, human interactions, and game rules. Classified into five groups based on their design principles, these are swarm-based, evolutionary-based, physics-based, human-based, and game-based approaches.

Swarm-based algorithms, like Particle Swarm Optimization (PSO) [11], Ant Colony Optimization (ACO) [12], Artificial Bee Colony (ABC) [13], and the Firefly Algorithm (FA) [14], emulate the behaviors of animals, insects, plants, birds, and aquatic life. PSO models the group movement of birds or fish searching for food, ACO is inspired by ants finding the shortest communication path, ABC mimics honey bees’ activities in locating food, and the FA replicates fireflies’ optical communication. Noteworthy wildlife activities, such as foraging, hunting, chasing, migration, and digging, serve as the foundation for swarm-based metaheuristic algorithms like the Pufferfish Optimization Algorithm (POA) [15], Golden Jackal Optimization (GJO) [16], Tunicate Swarm Algorithm (TSA) [17], Coati Optimization Algorithm (COA) [18], Chameleon Swarm Algorithm (CSA) [19], Wild Geese Algorithm (WGA) [20], White Shark Optimizer (WSO) [21], Grey Wolf Optimizer (GWO) [22], African Vultures Optimization Algorithm (AVOA) [23], Mantis Search Algorithm (MSA) [24], Marine Predator Algorithm (MPA) [25], Whale Optimization Algorithm (WOA) [26], Orca Predation Algorithm (OPA) [27], Reptile Search Algorithm (RSA) [28], Honey Badger Algorithm (HBA) [29], and Kookaburra Optimization Algorithm (KOA) [30].

Evolutionary-based metaheuristic algorithms derive inspiration from the biological sciences, genetics, survival of the fittest, natural selection, and random operators. Prominent algorithms in this group include the Genetic Algorithm (GA) [31] and Differential Evolution (DE) [32], designed to emulate reproduction and Darwin’s theory of evolution, and to incorporate random operators like mutation, crossover, and selection. Artificial Immune Systems (AISs) are modeled after the human body’s defense system [33]. Other algorithms in this category encompass Genetic Programming (GP) [34], Cultural Algorithm (CA) [35], and Evolution Strategy (ES) [36].

Physics-based metaheuristic algorithms are developed by simulating laws, forces, transformations, and other concepts from physics. Simulated Annealing (SA) [37], a widely used algorithm in this category, emulates the metal annealing process, where metals are melted and slowly cooled to achieve optimal crystal formation. Various algorithms, including the Momentum Search Algorithm (MSA) [38], Spring Search Algorithm (SSA) [39], and Gravitational Search Algorithm (GSA) [40], are based on physical forces and Newton’s laws of motion. The Black Hole Algorithm (BHA) [41] and Multi-Verse Optimizer (MVO) [42] draw inspiration from cosmological concepts. Other physics-based metaheuristic algorithms include the Equilibrium Optimizer (EO) [43], Archimedes Optimization Algorithm (AOA) [44], Henry Gas Optimization (HGO) [45], Electro-Magnetism Optimization (EMO) [46], Lichtenberg Algorithm (LA) [47], Nuclear Reaction Optimization (NRO) [48], Thermal Exchange Optimization (TEO) [49], and Water Cycle Algorithm (WCA) [50].

Human-based metaheuristic algorithms are designed to emulate human behaviors, interactions, thoughts, and social activities. Notably, Teaching–Learning-Based Optimization (TLBO) draws inspiration from educational interactions in classrooms, simulating knowledge exchange among teachers and students [51]. The Special Forces Algorithm (SFA) mirrors real-life special forces missions, incorporating mechanisms to simulate UAV-assisted searches and contact loss due to force majeure [52]. The Political algorithm (PO) [53] replicates democratic parliamentary politics, offering a unique optimization approach inspired by political decision-making dynamics. The Chef-Based Optimization Algorithm (CHBO) [54] takes cues from individuals learning cooking skills in classes. Other human-based metaheuristic algorithms include the Coronavirus Herd Immunity Optimizer (CHIO) [55], Doctor and Patient Optimization (DPO) [56], War Strategy Optimization (WSO) [57], Election-Based Optimization Algorithm (EBOA) [58], Gaining Sharing Knowledge-Based Algorithm (GSK) [59], Following Optimization Algorithm (FOA) [60], Driving Training-Based Optimization (DTBO) [5], Sewing Training-Based Optimization (STBO) [61], and Ali Baba and the Forty Thieves (AFT) [62].

Game-based metaheuristic algorithms are formulated by simulating player behavior, influential figures, and the rules of various individual and team games. Algorithms like Football Game-Based Optimization (FGBO) [63] and Volleyball Premier League (VPL) [64] are inspired by modeling league matches. The Hide Object Game Optimizer (HOGO) [65] is designed based on players’ attempts to locate hidden objects on the playing field. The Darts Game Optimizer (DGO) [66] incorporates the skill of players throwing darts to earn more points. The Orientation Search Algorithm (OSA) [67] emulates players’ movements directed by referees. Other game-based metaheuristic algorithms include the Dice Game Optimizer (DGO) [68], Golf Optimization Algorithm (GOA), League Championship Algorithm (LCA) [6], Ring Toss Game-Based Optimization (RTGBO) [69], and Puzzle Optimization Algorithm (POA) [70].

In addition to the original versions of metaheuristic algorithms, many researchers have tried to improve the performance of existing algorithms by developing their improved versions, such as the Enhanced Snake Optimizer (ESO) [71], Improved Sparrow Search Algorithm (ISSA) [72], and multi-strategy-based Adaptive Sine–Cosine Algorithm (ASCA) [73].

To the best of our knowledge, as gleaned from the literature review, no metaheuristic algorithm inspired by the human activity of Botox injections has been introduced thus far. The process of enhancing facial beauty by injecting substances to eliminate facial defects presents an intelligent methodology that could serve as the foundation for a novel metaheuristic algorithm. To bridge this research gap in metaheuristic algorithm studies, this paper introduces a new human-based metaheuristic algorithm, grounded in the mathematical modeling of Botox injections in specific facial areas, as elaborated in the subsequent section.

3. Botox Optimization Algorithm

Within this section, the Botox Optimization Algorithm (BOA) is elucidated, beginning with an exploration of its theory and source of inspiration. Following this, the mathematical modeling of the implementation steps for the proposed BOA approach is detailed.

3.1. Inspiration of BOA

Enhancing facial beauty is a significant and intricate concern for many individuals, with the emergence of facial wrinkles often causing distress. Wrinkles result from the repetitive contraction of underlying facial muscles and dermal atrophy. To address this issue, small doses of botulinum toxin are strategically injected into specific overactive muscles. This injection induces localized muscle relaxation, subsequently leading to the smoothing of the skin in these hyperactive muscle areas [74]. Botulinum toxin, a potent neurotoxin protein derived from the bacterium Clostridium botulinum, is employed for this purpose. The administration of this toxin results in the targeted muscles being temporarily paralyzed, preventing the formation of wrinkles in the treated area [75]. Botox, the cosmetic use of botulinum toxin, gained approval from the U.S. Food and Drug Administration (FDA) in 2002 for treating glabellar complex muscles responsible for frown lines, and in 2013 for addressing lateral orbicularis oculi muscles associated with crow’s feet [76].

Botox exerts a significant impact on diminishing facial wrinkles and enhancing facial aesthetics. The strategic injection of Botox into specific facial areas to eliminate wrinkles serves as an intelligent process, forming the foundational concept behind the design of the approach proposed by the BOA.

3.2. Algorithm Initialization

The proposed BOA methodology operates as a population-based optimizer, leveraging the collective search capabilities of its participants in an iterative process to generate viable solutions for optimization problems. In this context, individuals seeking Botox injections constitute the BOA population. Each member contributes to decision variable values based on their position in the problem-solving space, mathematically represented as a vector. This vector, encapsulating decision variables, forms the population matrix outlined in Equation (1); initialization of each BOA member’s position is achieved through random assignment using Equation (2):

X=X1XiXNN×m=x1,1x1,dx1,mxi,1xi,dxi,mxN,1xN,dxN,mN×m, (1)
xi,d=lbd+ri,d·(ubdlbd), i=1,,N, d=1,,m, (2)

where X is the BOA population matrix, Xi is the ith BOA member (candidate solution), xi,d is its dth dimension in the search space (decision variable), N is the number of population members, m is the number of decision variables, ri,d are random numbers from interval 0, 1, and lbd and ubd are the lower bound and upper bound of the dth decision variable, respectively.

Given that each member in the BOA population represents a candidate solution for the problem, the associated objective function of the problem can be assessed for each individual. Consequently, the array of objective function values can be depicted as a vector, as per Equation (3):

F=F1FiFNN×1=F(X1)F(Xi)F(XN)N×1, (3)

where F is the vector of the evaluated objective function and Fi is the evaluated objective function based on the ith BOA member.

The assessed objective function values serve as reliable criteria for appraising the quality of candidate solutions. Consequently, the optimal member of the BOA corresponds to the best value achieved for the objective function, while the suboptimal member aligns with the worst value. Given that the position of BOA population members and their objective function values are updated in each iteration, the best candidate solution undergoes regular updates.

3.3. Mathematical Modeling of BOA

The BOA approach, a population-based optimizer, adeptly furnishes viable solutions for optimization problems through an iterative process. In the BOA’s design, inspiration is drawn from the Botox injection mechanism to update the position of population members within the search space. The schematic of Botox injection and its simulation to design the proposed BOA approach is shown in Figure 1.

Figure 1.

Figure 1

Schematic diagram of the Botox injection and the proposed BOA.

Each individual seeking Botox injections represents a member of the BOA population. The BOA design mirrors the process of a doctor injecting Botox into specific facial muscles to diminish wrinkles and enhance beauty. Similarly, in the BOA approach, improvement to a candidate solution involves adding a designated value, akin to Botox, to select decision variables.

In the design of the BOA, it is considered that the number of facial muscles that need to be injected with Botox decreases during the iterations of the algorithm. Therefore, the number of selected muscles (i.e., decision variables) for Botox injection is determined by using Equation (4):

Nb=1+mtm, (4)

where Nb is the number of muscles requiring Botox injection and t is the current value of the iteration counter.

When the applicant visits the doctor, the doctor decides which muscles to inject Botox into, based on the person’s face and wrinkles. Inspired by this fact, in BOA design, the variables to be injected are selected for each population member using Equation (5). It should be noted that the muscles that are chosen for Botox injection should not be repeated, which is considered in Equation (5):

CBSi=d1, d2, ,dj, ,dNb , dj1,2, ,m  and  h,k1,2, ,Nb:dhdk. (5)

Thus, CBSi is the set of candidate decision variables of the ith population member that are selected for Botox injection, and dj is the position of the jth decision variable selected for Botox injection.

In the BOA design, akin to the doctor’s discretion in determining the drug quantity for Botox injection based on expertise and patient needs, the amount of Botox injection for each population member is computed using Equation (6):

Bi=XmeanXi, t<T2 ;XbestXi, else, (6)

where Bi=(bi,1,,bi,j,,bi,m) is the considered amount for Botox injection to the ith member, Xmean is the mean population position (i.e., Xmean=1Ni=1NXi), T is the total number of iterations, and Xbest is the best population member.

After Botox injection into the facial muscles, the appearance of the face changes, with the disappearance of wrinkles. In the BOA design, based on the simulation of Botox injection to the facial muscles, first, a new position is calculated for each BOA member based on Botox injection using Equation (7); then, if the value of the objective function is improved, this new position replaces the previous position of the corresponding member according to Equation (8):

Xinew: xi,djnew=xi,dj+ri,dj·bi,dj, (7)
Xi=Xinew, Finew<FiXi, else, (8)

where Xinew is the new position of the ith BOA member after Botox injection,  xi,djnew is its djth dimension, Finew is its objective function value, ri,dj is a random number with a uniform distribution on the interval 0, 1, and bi,dj is the djth dimension of Botox injection for the ith BOA member (i.e., Bi).

3.4. Repetition Process, Pseudocode, and Flowchart of the BOA

After updating the position of all BOA members in the search space, the first iteration of the algorithm is completed. Then, based on the updated values, the algorithm enters the next iteration, and the process of updating the BOA population members continues until the last iteration, based on Equations (4)–(8). In each iteration, the best obtained candidate solution Xbest is also updated and saved. After the full implementation of the proposed BOA approach, the best candidate solution Xbest stored during the iterations of the algorithm is introduced as the solution to the given problem. The steps of BOA implementation are presented in the form of a flowchart in Figure 2, and its pseudocode is shown in Algorithm 1.

Algorithm 1. Pseudocode of the BOA.
Start the BOA.
1. Input problem information: variables, objective function, and constraints.
2. Set the BOA population size N and the total number of iterations T.
3. Generate the initial population matrix at random using Equation (2).
4. Evaluate the objective function.
5. Determine the best candidate solution Xbest.
6. For t=1 to T
7.   Update number of decision variables for Botox injections using Equation (4).
8.   For i=1 to N
9.  Determine the variables that are considered for Botox injection using Equation (5).
10.  Calculate the amount of Botox injection using Equation (6).
11.  For j=1 to Nb
12.  Calculate the new position of the ith BOA member using Equation (7).
13.  End
14.  Evaluate the objective function based on Xinew.
15.  Update the ith BOA member using Equation (8).
16.   End
17.   Save the best candidate solution obtained so far.
18.   End
19.   Output the best quasi-optimal solution obtained with the BOA.
End the BOA.

Figure 2.

Figure 2

Flowchart of the BOA.

3.5. Computational Complexity of the BOA

In this subsection, the computational complexity of the BOA is evaluated. The preparation and initialization steps of the BOA for an optimization problem have a computational complexity equal to O(Nm), where N is the number of population members and m is the number of decision variables of the problem. In each iteration, the position of the population members is updated and the corresponding objective function is also evaluated. Therefore, the BOA update process has a computational complexity equal to O(NmT), where T is the maximum number of iterations of the algorithm. According to this, the total computational complexity of the proposed BOA approach is equal to O(Nm(1+T)).

3.6. Population Diversity, Exploration, and Exploitation Analysis

The population diversity of the BOA refers to the distribution of population members within the problem space, which plays a critical role in monitoring the search processes of the algorithm. Essentially, this metric indicates whether the population members are focused on exploration or exploitation. By measuring the diversity of the BOA population, it becomes possible to gauge and adapt the algorithm’s capacity to explore and exploit a collective group effectively. Various definitions of diversity have been put forth by researchers. Pant [77] defined diversity according to Equations (9) and (10):

Diversity=1Ni=1Nd=1mxi,dx¯d2, (9)
x¯d=1Ni=1Nxi,d (10)

where N is the number of population members, m is the number of problem dimensions, and x¯d is the mean of the entire population in the dth dimension. Hence, the percentage of exploration and exploitation of the population for each iteration can be defined by Equations (11) and (12), respectively:

Exploration=DiversityDiversitymax, (11)
Exploitation=1Exploration. (12)

In this subsection, the analysis of population diversity, exploration, and exploitation is evaluated on twenty-three standard benchmark functions, consisting of 7 unimodal functions (F1 to F7) and 16 multimodal functions (F8 to F23). A full description of these benchmark functions is available in [78].

Figure 3 illustrates the exploration–exploitation ratio of the BOA method throughout the iteration process, offering visual support for analyzing how the algorithm balances global and local search strategies. Also, the results of the analysis of population diversity, exploration, and exploitation are reported in Table 1. The simulation results show that the BOA has favorable population diversity, where it has high values in the first iteration, while the values of this index are low in the last iteration. Also, based on the obtained results, in most cases the exploration–exploitation ratio of the BOA is close to 0.00%:100%. The findings obtained from this analysis confirm that the proposed BOA approach, by creating the appropriate population diversity during the iterations of the algorithm, provides a favorable performance in managing exploration and exploitation, and in balancing them during the search process.

Figure 3.

Figure 3

Figure 3

Exploration and exploitation of the BOA.

Table 1.

Population diversity, exploration, and exploitation percentage results.

Function Name Exploration Exploitation Diversity
First Iteration Last Iteration
F1 0 1 140.5903 0
F2 0 1 10.94242 0
F3 0 1 252.3905 0
F4 0 1 128.8175 0
F5 0 1 44.92006 0
F6 0.012744 0.987256 114.0171 1.453073
F7 0.049372 0.950628 1.518403 0.074966
F8 5.84E-10 1 1230.61 1.19E-06
F9 4.76E-10 1 9.555822 4.55E-09
F10 1.8E-17 1 50.32814 9.04E-16
F11 3.7E-11 1 885.0467 3.27E-08
F12 0 1 61.45876 0
F13 0 1 77.58755 0
F14 2.02E-08 1 23.65722 4.77E-07
F15 5.93E-11 1 4.048837 2.4E-10
F16 0.082221 0.917779 1.61018 0.13239
F17 6.68E-10 1 4.961695 3.31E-09
F18 0.068118 0.931882 0.757968 0.051631
F19 0.245007 0.754993 0.378584 0.118559
F20 0.054777 0.945223 0.441119 0.024163
F21 1.95E-10 1 3.149125 7.25E-10
F22 1.36E-10 1 3.505294 6.63E-10
F23 9.32E-11 1 4.347473 4.27E-10

4. Simulation Studies and Results

In this section, the performance of the proposed BOA approach in handling optimization tasks is evaluated.

4.1. Performance Comparison

To assess the BOA’s effectiveness in addressing optimization problems, its results were juxtaposed with those of twelve prominent metaheuristic algorithms: the GA [31], PSO [11], GSA [40], TLBO [51], MVO [42], GWO [22], WOA [26], MPA [25], TSA [17], RSA [28], AVOA [23], and WSO [21]. These twelve algorithms were selected from the numerous algorithms available in the literature. The reasons for choosing these twelve algorithms were as follows: the GA and PSO are among the first and most famous metaheuristic algorithms. The GSA, TLBO, MVO, GWO, and WOA are among the most cited metaheuristic algorithms that have been used in various optimization applications. The MPA, TSA, RSA, AVOA, and WSO approaches are among the recently published successful metaheuristic algorithms that have attracted the attention of many researchers in this short period of time. Comparing the proposed BOA approach with these twelve selected metaheuristic algorithms is a valuable comparison, after which the efficiency of the BOA will have been tested well. Table 2 outlines the control parameter values for the competing algorithms. The evaluation of the simulation results incorporates six statistical metrics: mean, best, worst, standard deviation (std), median, and rank. The mean index values were utilized for ranking the metaheuristic algorithms concerning each benchmark function.

Table 2.

Control parameters’ values.

Algorithm Parameter Value
GA
Type Real coded
Selection Roulette wheel (proportionate)
Crossover Whole arithmetic (Probability=0.8,
α0.5,1.5)
Mutation Gaussian (Probability=0.05)
PSO
Topology Fully connected
Cognitive and social constant (C1, C2=(2,2)
Inertia weight Linear reduction from 0.9 to 0.1
Velocity limit 10% of dimension range
GSA
Alpha, G0, Rnorm, Rpower 20, 100, 2, 1
TLBO
TF: Teaching factor TF=round  (1+rand)
Random number rand is a random number from 0,1.
GWO
Convergence parameter (a) a: Linear reduction from 2 to 0.
MVO
Wormhole Existence Probability (WEP) Min(WEP)=0.2 and Max(WEP)=1.
Exploitation accuracy over the iterations (p) p=6.
WOA
Convergence parameter (a) a: Linear reduction from 2 to 0.
r is a random vector in 0, 1;
l is a random number in 1, 1
TSA
Pmin,Pmax 1, 4
c1,c2, c3 Random numbers lie in the interval 0,1.
MPA
Constant number P=0.5
Random vector R is a vector of uniform random numbers in 0,1.
Fish Aggregating Devices (FADs) FADs=0.2
Binary vector U=0 or 1
RSA
Sensitive parameter β=0.01
Sensitive parameter α=0.1
Evolutionary Sense (ES) ES: Randomly decreasing values between 2 and −2
AVOA
L1,L2 0.8, 0.2
w 2.5
P1,P2,P3 0.6, 0.4, 0.6
WSO
Fmin,Fmax 0.07, 0.75
τ, a0,a1,a2 4.125, 6.25, 100, 0.0005

4.2. Evaluation of the CEC 2017 Test Suite

In this section, the performance of the BOA and competing algorithms is evaluated using the CEC 2017 test suite, considering problem dimensions (number of decision variables) equal to 10, 30, 50, and 100. The CEC 2017 test suite comprises thirty benchmark functions, including three unimodal functions (C17-F1 to C17-F3), seven multimodal functions (C17-F4 to C17-F10), ten hybrid functions (C17-F11 to C17-F20), and ten composition functions (C17-F21 to C17-F30). The C17-F2 function is excluded due to its unstable behavior, as described in [79].

The results of employing the BOA approach and competing algorithms on the CEC 2017 test suite are presented in Table 3. Boxplot diagrams depicting the performance of the BOA and competing algorithms in optimizing the CEC 2017 test suite are illustrated in Figure 4. The outcomes indicate that the BOA outperformed other optimizers, ranking as the top performer for functions C17-F1, C17-F3 to C17-F21, C17-F23, C17-F24, and C17-F27 to C17-F30.

Table 3.

Optimization results of the CEC 2017 test suite.

BOA WSO AVOA RSA MPA TSA WOA MVO GWO TLBO GSA PSO GA
C17-F1 Mean 100 5.46E+09 3848.625 1.02E+10 35,331,826 1.74E+09 6,458,531 7530.831 88,328,653 1.47E+08 747.4345 3148.604 11,867,816
Best 100 4.59E+09 115.6391 8.84E+09 11,218.07 3.73E+08 4,702,752 4790.099 27,833.68 65,653,192 100.0193 345.9935 6,145,607
Worst 100 6.85E+09 11,928.77 1.22E+10 1.28E+08 3.8E+09 8,503,451 11,096.78 3.21E+08 3.56E+08 1792.381 9323.402 17,037,274
Std 0 1.07E+09 6005.345 1.64E+09 67,796,179 1.66E+09 1,750,529 3215.353 1.69E+08 1.52E+08 796.8781 4524.035 4,954,471
Median 100 5.21E+09 1675.046 9.94E+09 6,476,105 1.4E+09 6,313,960 7118.225 16,188,754 84,181,901 548.6691 1462.51 12,144,191
Rank 1 12 4 13 8 11 6 5 9 10 2 3 7
C17-F3 Mean 300 7591.42 301.8957 9658.226 1408.746 11,214.42 1731.412 300.0547 3071.866 726.7343 10,268.87 300 14,789.2
Best 300 4113.783 300 5207.518 791.8459 4270.307 619.6359 300.0127 1529.615 471.4213 6461.812 300 4354.021
Worst 300 10,174.7 304.0548 12,922.2 2537.378 15,855.2 3333.866 300.1245 5893.445 893.5147 13,957.47 300 23,376.32
Std 0 2896.121 2.393662 3838.968 876.4573 5353.91 1391.667 0.05345 2191.143 201.3742 3364.571 5.05E-14 10,814.33
Median 300 8038.595 301.764 10,251.59 1152.881 12,366.08 1486.072 300.0407 2432.202 771.0005 10,328.09 300 15,713.23
Rank 1 9 4 10 6 12 7 3 8 5 11 2 13
C17-F4 Mean 400 919.2957 404.7605 1352.77 406.7394 576.7582 425.1975 403.341 411.7605 409.1884 404.5619 420.3519 414.7475
Best 400 672.5461 401.2436 845.7611 402.4511 477.9916 406.4543 401.5971 406.1014 408.4021 403.5684 400.1059 411.7011
Worst 400 1142.743 406.5393 1849.389 411.4014 692.0754 473.6998 404.9048 428.4155 409.6849 406.0879 470.5109 418.4747
Std 0 229.2926 2.715361 466.2296 4.804772 114.2038 35.29756 1.871726 12.08414 0.598616 1.257481 36.76729 3.226255
Median 400 930.9465 405.6296 1357.964 406.5525 568.4828 410.3179 403.431 406.2626 409.3334 404.2956 405.3954 414.407
Rank 1 12 4 13 5 11 10 2 7 6 3 9 8
C17-F5 Mean 501.2464 562.2888 544.5598 573.6638 513.037 565.1128 541.4479 523.9769 513.1801 534.4525 554.4872 528.2287 528.3418
Best 500.9951 547.4308 527.1499 558.8475 508.4371 543.7341 523.7238 510.3406 508.6157 528.9014 549.5681 511.27 523.5807
Worst 501.9917 572.2487 563.5795 588.8477 518.2122 597.5197 577.7367 538.4222 520.5555 538.0275 566.3814 552.3704 534.175
Std 0.540776 12.11165 20.81022 18.12589 5.591417 25.96825 27.5346 12.761 5.604703 4.364766 8.746105 20.64316 5.206467
Median 500.9993 564.7379 543.7549 573.48 512.7494 559.5987 532.1655 523.5724 511.7746 535.4404 550.9996 524.6372 527.8058
Rank 1 11 9 13 2 12 8 4 3 7 10 5 6
C17-F6 Mean 600 632.7824 617.595 641.3535 601.2128 625.225 623.5356 602.184 601.1449 606.9718 617.4791 607.548 610.4234
Best 600 628.194 616.5747 638.0899 600.7222 615.3143 607.646 600.4796 600.6055 604.8344 602.9627 601.3762 607.0149
Worst 600 637.5379 620.1871 645.6746 602.4363 641.0634 645.9187 604.3818 601.7463 610.3045 636.7176 619.5657 614.7356
Std 0 4.413003 1.88613 3.709445 0.889975 12.08883 17.5391 1.908475 0.513952 2.714097 16.99487 8.979175 3.72455
Median 600 632.699 616.8091 640.8248 600.8464 622.2611 620.2889 601.9373 601.1139 606.3741 615.1181 604.6251 609.9715
Rank 1 12 9 13 3 11 10 4 2 5 8 6 7
C17-F7 Mean 711.1267 797.8688 766.4303 805.8543 724.8556 830.358 762.9002 731.196 726.2532 752.71 717.2159 733.0903 737.2869
Best 710.6726 780.6589 744.4304 792.4154 720.5783 789.6269 751.7383 717.2818 717.5639 748.1129 714.8806 725.8012 726.7599
Worst 711.7995 809.4588 794.6393 818.7295 729.351 872.5061 792.8006 750.7791 744.0606 760.9719 721.0193 744.8461 741.9507
Std 0.557384 13.284 25.13695 13.44422 4.022787 39.18582 21.75715 15.33828 13.2473 6.2627 2.892038 9.451487 7.758608
Median 711.0174 800.6788 763.3257 806.1362 724.7466 829.6494 753.531 728.3615 721.6942 750.8777 716.4818 730.8569 740.2185
Rank 1 11 10 12 3 13 9 5 4 8 2 6 7
C17-F8 Mean 801.4928 848.1769 831.617 854.5622 812.8571 849.0636 836.9437 812.0059 816.0909 838.313 820.1744 823.1267 817.0493
Best 800.995 842.8959 820.611 843.1502 808.9812 832.594 818.8766 807.536 810.6855 831.2975 812.2041 815.9405 813.0058
Worst 801.9912 854.7381 847.6997 859.9005 815.0312 868.6915 849.3401 816.8821 821.1703 846.4472 828.0838 829.679 824.9831
Std 0.625636 6.701009 12.45098 8.409374 3.041009 17.47606 14.23885 4.180792 4.773722 8.432783 7.354204 7.407172 5.86208
Median 801.4926 847.5368 829.0787 857.599 813.708 847.4845 839.779 811.8029 816.2538 837.7536 820.2048 823.4438 815.1042
Rank 1 11 8 13 3 12 9 2 4 10 6 7 5
C17-F9 Mean 900 1430.961 1192.849 1476.617 905.2837 1388.608 1383.102 900.8146 912.1313 912.0221 900 904.3122 905.1958
Best 900 1276.126 954.6109 1379.243 900.3329 1172.43 1076.987 900.0011 900.5827 907.3517 900 900.9142 902.8443
Worst 900 1573.852 1673.688 1616.361 913.5628 1681.601 1668.813 903.166 933.6785 920.3352 900 912.5228 909.2282
Std 0 140.1941 362.6238 109.8787 6.480782 239.779 271.1443 1.706569 16.89776 6.209908 0 6.03293 3.14228
Median 900 1436.932 1071.549 1455.432 903.6196 1350.2 1393.304 900.0457 907.1319 910.2007 900 901.9059 904.3554
Rank 1 11 8 12 5 10 9 2 7 6 1 3 4
C17-F10 Mean 1006.179 2311.834 1782.706 2588.899 1519.782 2039.361 2031.708 1785.695 1729.938 2179.736 2286.565 1951.968 1720.13
Best 1000.284 2010.815 1486.512 2416.757 1393.592 1762.237 1452.075 1458.762 1542.197 1786.243 2004.951 1563.92 1417.123
Worst 1012.668 2456.623 2423.148 2951.232 1595.402 2293.271 2559.74 2290.911 1998.556 2469.964 2393.264 2360.873 2118.219
Std 7.244311 225.7849 478.7803 270.7973 103.4757 304.9995 582.7437 438.7957 211.0887 316.3582 204.7244 356.2546 327.1839
Median 1005.882 2389.949 1610.583 2493.804 1545.066 2050.967 2057.508 1696.554 1689.498 2231.369 2374.023 1941.539 1672.588
Rank 1 12 5 13 2 9 8 6 4 10 11 7 3
C17-F11 Mean 1100 3442.37 1148.775 4000.383 1127.198 5484.031 1151.243 1127.661 1155.582 1151.197 1139.413 1143.772 2389.968
Best 1100 2188.762 1117.145 1460.621 1113.275 5334.971 1113.032 1105.577 1121.743 1138.044 1119.755 1132.432 1115.129
Worst 1100 4665.813 1202.357 6508.91 1159.111 5565.816 1173.513 1149.188 1229.094 1172.713 1169 1165.388 6006.61
Std 0 1210.189 40.81842 2469.216 23.5556 111.6604 30.39483 23.71355 54.46268 16.28689 22.87379 16.15173 2624.636
Median 1100 3457.454 1137.8 4016 1118.203 5517.668 1159.213 1127.94 1135.746 1147.016 1134.448 1138.634 1219.067
Rank 1 11 6 12 2 13 8 3 9 7 4 5 10
C17-F12 Mean 1352.959 3.57E+08 1,109,704 7.11E+08 572,257.8 1,048,288 2,373,547 1,037,633 1,427,055 5,094,522 1,028,834 8145.64 610,018.9
Best 1318.646 80,192,749 358,948.9 1.58E+08 20,015.65 543,606.5 173,159.8 8892.711 45,801.15 1,363,349 478,453.6 2528.033 176,684.6
Worst 1438.176 6.23E+08 2,012,446 1.24E+09 895,571.3 1,286,990 3,937,641 3,259,364 2,233,764 9,018,848 1,739,931 14,021.19 1,076,854
Std 62.35801 2.98E+08 841,688.2 5.98E+08 419,783.3 381,500.6 1,904,475 1,634,093 1,049,512 4,413,129 581,137.5 5698.792 402,260.9
Median 1327.506 3.62E+08 1,033,710 7.22E+08 686,722.1 1,181,277 2,691,694 441,138.1 1,714,326 4,997,944 948,475.7 8016.671 593,268.4
Rank 1 12 8 13 3 7 10 6 9 11 5 2 4
C17-F13 Mean 1305.324 17,335,628 18,471.94 34,661,545 5468.243 12,831.35 7630.328 6772.94 10,372.78 16,852.54 10,143.18 6664.754 54,887.32
Best 1303.114 1,445,254 2734.676 2,877,682 3740.627 7639.26 3297.206 1386.726 6550.028 15,912.77 5078.007 2387.751 8603.051
Worst 1308.508 57,542,238 31,658.65 1.15E+08 6689.907 20,335.57 15,267.01 12,470.28 14,494.81 19,148.28 14,291.03 16,841.17 181,516.7
Std 2.473462 29,234,423 16,273.34 58,465,686 1530.879 5963.582 5938.403 6247.984 3543.419 1681.501 4237.976 7465.241 91,927.81
Median 1304.837 5,177,510 19,747.21 10,349,214 5721.218 11,675.29 5978.549 6617.376 10,223.15 16,174.55 10,601.85 3715.048 14,714.78
Rank 1 12 10 13 2 8 5 4 7 9 6 3 11
C17-F14 Mean 1400.746 3828.915 2027.645 5383.694 1945.167 3405.109 1520.154 1573.519 2355.252 1592.631 5604.306 3010.581 13,069.42
Best 1400 3170.6 1681.663 4711.086 1435.363 1488.751 1482.596 1423.322 1462.902 1517.224 4631.803 1432.831 3748.476
Worst 1400.995 5066.928 2841.448 6948.68 2917.489 5622.496 1560.295 1999.133 4996.706 1623.198 7611.074 6894.737 26,056.87
Std 0.541408 945.4187 594.8446 1143.911 756.5397 2393.086 43.20222 308.8712 1916.5 54.97335 1519.18 2840.855 10,284.68
Median 1400.995 3539.066 1793.735 4937.505 1713.908 3254.594 1518.862 1435.81 1480.701 1615.05 5087.174 1857.377 11,236.18
Rank 1 10 6 11 5 9 2 3 7 4 12 8 13
C17-F15 Mean 1500.331 10,283.95 5333.31 13,989.15 3998.841 7053.662 6262.146 1542.234 5854.355 1711.148 24,088.27 9066.744 4578.338
Best 1500.001 3259.43 2077.801 2745.559 3239.281 2327.191 2019.265 1526.157 3589.383 1584.901 11,316.55 2884.332 1894.197
Worst 1500.5 17,559.48 12,730.21 30,627 4923.526 12,648.29 13,558.05 1554.385 6950.016 1801.652 36,159.61 14,917.69 8074.57
Std 0.256213 6701.944 5408.362 13,248.87 760.3969 4827.04 5473.801 13.4196 1680.534 115.7645 12,916.31 5473.312 3344.03
Median 1500.413 10,158.45 3262.612 11,292.03 3916.279 6619.585 4735.634 1544.197 6439.01 1729.02 24,438.46 9232.477 4172.293
Rank 1 11 6 12 4 9 8 2 7 3 13 10 5
C17-F16 Mean 1600.76 2006.472 1811.471 2020.201 1684.989 2051.36 1953.664 1818.204 1729.658 1677.592 2077.466 1926.579 1804.186
Best 1600.356 1936.677 1642.633 1821.325 1642.119 1864.782 1766.603 1727.666 1615.96 1651.389 1950.251 1824.477 1719.79
Worst 1601.12 2125.766 1929.19 2296.53 1715.87 2237.602 2083.047 1880.447 1827.504 1732.365 2274.078 2087.786 1835.532
Std 0.343807 91.7687 131.3759 218.4156 34.5268 184.0946 163.6931 70.32367 94.99226 41.07563 160.2418 132.7396 61.28572
Median 1600.781 1981.722 1837.031 1981.476 1690.984 2051.528 1982.503 1832.352 1737.585 1663.306 2042.768 1897.026 1830.712
Rank 1 10 6 11 3 12 9 7 4 2 13 8 5
C17-F17 Mean 1700.099 1823.352 1751.466 1819.495 1736.079 1803.161 1843.24 1844.13 1769.181 1758.941 1848.159 1752.864 1756.518
Best 1700.02 1806.066 1734.73 1802.424 1722.121 1787.826 1774.309 1779.25 1724.691 1748.708 1748.396 1746.15 1753.36
Worst 1700.332 1830.672 1795.908 1828.806 1775.629 1814.158 1891.142 1952.846 1873.227 1768.986 1975.689 1759.617 1758.979
Std 0.168864 12.61303 32.32876 12.76453 28.70898 12.30981 55.23119 89.45313 75.87461 10.92649 126.1415 6.267908 2.763929
Median 1700.022 1828.335 1737.613 1823.375 1723.282 1805.33 1853.755 1822.211 1739.404 1759.036 1834.276 1752.844 1756.867
Rank 1 10 3 9 2 8 11 12 7 6 13 4 5
C17-F18 Mean 1805.36 2,877,257 11,923.85 5,735,592 11,111.67 12,127.7 23,449.89 21,073.62 20,025.71 29,687.97 9765.664 22,009.06 12,887.9
Best 1800.003 148,282.3 4864.976 283,924 4174.747 7503.888 6480.271 8747.673 6354.336 24,138.12 6424.12 2888.071 3447.217
Worst 1820.451 8,337,684 15,688.36 16,650,123 16,616.76 16,384.43 36,839.48 33,922.95 33,800.34 37,134.83 11,923.34 40,997.79 18,593.6
Std 10.95197 4,127,821 5281.26 8,252,643 6158.261 4019.381 15,920.68 12,898.77 15,147.08 6506.053 2554.342 21,410.87 7199.978
Median 1800.492 1,511,530 13,571.04 3,004,161 11,827.6 12,311.24 25,239.9 20,811.92 19,974.07 28,739.47 10,357.6 22,075.19 14,755.39
Rank 1 12 4 13 3 5 10 8 7 11 2 9 6
C17-F19 Mean 1900.445 390,051.5 6740.448 708,553.5 5623.033 126,338 35,023.84 1914.851 5407.081 4715.34 40,679.05 25,099.05 6211.208
Best 1900.039 25,762.01 2178.665 46,105.64 2320.659 1949.556 7697.99 1909.484 1944.955 2044.21 11,164.51 2629.429 2215.362
Worst 1901.559 821,920.8 13,319.27 1,522,124 9466.148 252,369.2 64,127.87 1924.471 13,887.85 12,559.69 59,008.83 77,380.53 9935.635
Std 0.810364 378,831.5 5895.722 724,659.8 3963.615 156,290.3 25,211.41 7.70358 6217.733 5691.553 23,319.35 38,358.7 3466.525
Median 1900.09 356,261.6 5731.927 632,992.2 5352.663 125,516.6 34,134.74 1912.724 2897.759 2128.73 46,271.42 10,193.12 6346.918
Rank 1 12 7 13 5 11 9 2 4 3 10 8 6
C17-F20 Mean 2000.312 2216.383 2171.683 2224.494 2092.931 2208.745 2207.956 2140.477 2171.033 2072.475 2255.372 2170.09 2050.542
Best 2000.312 2165.24 2031.536 2165.608 2073.228 2107.405 2098.976 2047.247 2131.776 2061.375 2189.014 2145.806 2036.046
Worst 2000.312 2283.827 2296.441 2280.283 2123.641 2323.021 2289.781 2249.067 2247.625 2082.964 2349.088 2202.147 2058.359
Std 0 53.77105 129.6972 61.41781 23.50952 99.40453 99.264 90.18592 56.83593 9.850576 84.75517 30.47507 11.19601
Median 2000.312 2208.232 2179.377 2226.043 2087.428 2202.278 2221.533 2132.797 2152.365 2072.78 2241.692 2166.204 2053.882
Rank 1 11 8 12 4 10 9 5 7 3 13 6 2
C17-F21 Mean 2200 2292.224 2213.908 2267.615 2257.617 2326.087 2310.663 2253.534 2314.124 2300.419 2369.547 2319.669 2298.888
Best 2200 2245.786 2204.158 2224.131 2255.109 2221.386 2218.528 2200.008 2309.885 2203.746 2351.941 2311.549 2226.752
Worst 2200 2321.323 2239.299 2292.339 2260.172 2373.39 2355.179 2308.4 2319.13 2339.391 2387.001 2327.277 2333.787
Std 0 37.4424 18.47872 32.82983 2.33168 77.27499 67.69154 67.27446 4.137785 70.64276 15.94573 8.418841 53.00527
Median 2200 2300.893 2206.088 2276.995 2257.593 2354.786 2334.472 2252.863 2313.74 2329.27 2369.622 2319.925 2317.506
Rank 1 6 2 5 4 12 9 3 10 8 13 11 7
C17-F22 Mean 2300.073 2701.027 2309.054 2920.786 2305.044 2717.182 2323.99 2285.662 2308.669 2319.729 2300.004 2313.376 2318.072
Best 2300 2581.071 2304.399 2710.209 2300.951 2450.338 2319.288 2228.873 2301.277 2313.416 2300 2300.643 2315.149
Worst 2300.29 2820.282 2311.236 3075.328 2309.437 2926.716 2331.697 2305.332 2322.59 2331.562 2300.018 2345.833 2322.574
Std 0.157893 114.9318 3.421932 167.3244 3.892406 231.3835 6.033524 41.21509 10.66841 9.036157 0.009658 23.59913 3.452639
Median 2300 2701.377 2310.292 2948.804 2304.894 2745.837 2322.488 2304.221 2305.405 2316.97 2300 2303.514 2317.282
Rank 3 11 6 13 4 12 10 1 5 9 2 7 8
C17-F23 Mean 2600.919 2690.499 2642.521 2701.598 2614.457 2724.652 2649.231 2620.453 2613.868 2643 2793.704 2644.76 2656.735
Best 2600.003 2655.377 2630.851 2672.314 2611.98 2634.724 2631.18 2607.24 2607.853 2632.022 2728.026 2637.475 2636.591
Worst 2602.87 2710.595 2660.461 2742.593 2617.187 2769.526 2669.602 2632.143 2620.651 2652.382 2933.47 2656.811 2665.174
Std 1.436922 28.38289 15.1817 35.76758 2.682389 66.28428 22.5696 11.80644 7.173201 9.830174 105.0806 9.521171 14.8412
Median 2600.403 2698.012 2639.385 2695.743 2614.331 2747.18 2648.071 2621.215 2613.483 2643.799 2756.66 2642.376 2662.587
Rank 1 10 5 11 3 12 8 4 2 6 13 7 9
C17-F24 Mean 2630.488 2788.317 2768.95 2852.038 2630.654 2668.659 2761.886 2683.834 2749.937 2757.061 2748.612 2766.885 2724.025
Best 2516.677 2745.688 2736.941 2825.654 2617.619 2523.669 2736.445 2501.19 2726.533 2745.923 2502.655 2755.88 2536.059
Worst 2732.32 2856.987 2792.846 2913.462 2636.807 2812.827 2792.301 2759.842 2766.303 2767.028 2899.211 2786.936 2811.901
Std 126.7883 57.95513 27.89637 44.82121 9.562201 168.3131 25.02914 133.1237 19.19886 10.60604 186.1525 15.09998 137.7502
Median 2636.477 2775.296 2773.006 2834.518 2634.095 2669.069 2759.399 2737.151 2753.457 2757.647 2796.292 2762.363 2774.07
Rank 1 12 11 13 2 3 9 4 7 8 6 10 5
C17-F25 Mean 2932.639 3139.215 2913.317 3279.873 2917.765 3135.421 2907.315 2922.007 2938.751 2933.537 2922.179 2923.252 2952.419
Best 2898.047 3067.756 2899.104 3210.527 2913.428 2905.513 2763.108 2900.572 2921.074 2915.907 2902.261 2898.673 2938.562
Worst 2945.793 3299.244 2949.092 3356.883 2923.18 3664.488 2959.682 2943.722 2945.915 2952.388 2943.394 2946.56 2962.947
Std 25.12878 118.4951 26.01647 65.88501 4.450199 388.1053 104.7267 26.80868 12.86286 21.96492 24.96584 28.66542 11.32013
Median 2943.359 3094.931 2902.537 3276.041 2917.225 2985.842 2953.235 2921.867 2944.007 2932.927 2921.531 2923.888 2954.084
Rank 7 12 2 13 3 11 1 4 9 8 5 6 10
C17-F26 Mean 2900 3563.475 2980.612 3764.465 3012.721 3627.651 3185.71 2900.149 3268.794 3209.548 3870.812 2904.098 2897.19
Best 2900 3234.392 2806.117 3437.518 2892.04 3146.539 2927.473 2900.114 2969.885 2912.169 2806.117 2806.117 2705.581
Worst 2900 3783.253 3159.257 4104.73 3297.318 4282.661 3600.731 2900.195 3916.767 3885.046 4362.862 3010.276 3111.603
Std 4.04E-13 264.6671 219.3124 313.0895 207.4462 604.6037 320.3471 0.039308 474.4582 493.3205 785.0288 90.85344 223.8032
Median 2900 3618.128 2978.537 3757.805 2930.763 3540.701 3107.318 2900.144 3094.262 3020.488 4157.136 2900 2885.789
Rank 2 10 5 12 6 11 7 3 9 8 13 4 1
C17-F27 Mean 3089.518 3211.093 3120.294 3232.474 3104.836 3180.387 3195.929 3091.648 3116.364 3115.336 3227.33 3136.519 3160.678
Best 3089.518 3162.744 3095.362 3127.574 3092.27 3102.552 3179.884 3089.712 3094.484 3095.441 3215.052 3097.168 3119.628
Worst 3089.518 3293.2 3181.796 3426.382 3134.233 3223.046 3207.804 3095.016 3177.613 3172.045 3249.089 3184.29 3220.171
Std 2.86E-13 61.76378 44.75181 144.0715 21.48364 59.41073 12.68162 2.715154 44.48251 41.1546 16.48412 39.87289 46.26169
Median 3089.518 3194.214 3102.009 3187.971 3096.421 3197.974 3198.014 3090.932 3096.68 3096.929 3222.589 3132.309 3151.456
Rank 1 11 6 13 3 9 10 2 5 4 12 7 8
C17-F28 Mean 3100 3597.002 3237.24 3784.862 3219.529 3590.319 3288.358 3239.881 3346.978 3326.958 3453.664 3307.374 3247.568
Best 3100 3551.344 3100 3701.869 3167.488 3415.098 3153.13 3100.125 3195.479 3214.92 3440.292 3177.754 3145.253
Worst 3100 3629.166 3392.748 3844.77 3244.627 3801.261 3393.263 3392.749 3414.627 3392.992 3472.246 3392.965 3516.826
Std 0 37.84994 140.9244 72.18444 38.85546 217.9689 134.3096 175.9315 110.7805 92.50073 16.11354 106.1885 196.1013
Median 3100 3603.75 3228.106 3796.405 3232.999 3572.459 3303.518 3233.325 3388.902 3349.961 3451.059 3329.389 3164.097
Rank 1 12 3 13 2 11 6 4 9 8 10 7 5
C17-F29 Mean 3132.241 3341.543 3286.029 3377.573 3203.813 3237.271 3351.007 3203.391 3266.497 3213.443 3347.969 3267.377 3238.278
Best 3130.076 3320.37 3211.196 3305.533 3166.325 3166.435 3236.743 3142.631 3190.458 3166.015 3234.677 3168.273 3189.013
Worst 3134.841 3357.583 3367.588 3445.427 3245.657 3308.027 3499.364 3288.015 3381.802 3236.348 3639.853 3351.013 3287.876
Std 2.701544 16.93059 87.65176 78.4692 38.01024 63.06594 119.873 67.0027 99.05148 35.89995 212.6507 90.30554 45.26891
Median 3132.023 3344.109 3282.666 3379.666 3201.635 3237.31 3333.962 3191.459 3246.864 3225.705 3258.672 3275.111 3238.111
Rank 1 10 9 13 3 5 12 2 7 4 11 8 6
C17-F30 Mean 3418.734 2,270,202 296,246.2 3,694,956 416,890.8 617,692.3 997,284.6 304,439.1 940,663.9 60,930.4 786,751.4 389,254.4 1,535,217
Best 3394.682 1,673,245 105,205.9 831,886.7 15,996.07 112,875.5 4471.247 7460.759 33,746.81 29,426.72 604,858.7 6409.895 528,520.6
Worst 3442.907 3,240,778 771,775.4 5,836,135 615,301.1 1,306,089 3,764,900 1,160,773 1,361,385 102,270.8 1,004,710 771,812.2 3,497,487
Std 30.22288 740,116 345,952.7 2,280,306 296,209 551,800.6 2,010,505 621,503.5 678,871.6 38,719.09 180,833.5 480,108.6 1,523,052
Median 3418.673 2,083,393 154,001.9 4,055,902 518,132.9 525,902.3 109,883.7 24,761.28 1,183,762 56,012.05 768,718.5 389,397.8 1,057,430
Rank 1 12 3 13 6 7 10 4 9 2 8 5 11
Sum rank 38 318 177 350 106 286 239 116 188 191 238 183 197
Mean rank 1.310345 10.96552 6.103448 12.06897 3.655172 9.862069 8.241379 4 6.482759 6.586207 8.206897 6.310345 6.793103
Total rank 1 12 4 13 2 11 10 3 6 7 9 5 8

Figure 4.

Figure 4

Figure 4

Boxplot representations illustrating the performances of the BOA and rival algorithms on the CEC 2017 test suite.

Overall, the BOA demonstrated its efficacy in providing effective solutions for the CEC 2017 test suite, showcasing a commendable ability to explore, exploit, and maintain balance throughout the search process. The simulation results establish the BOA’s superior performance over competing algorithms, securing the top rank as the best optimizer for handling the CEC 2017 test suite.

4.3. Statistical Analysis

In this section, a statistical analysis was performed on the performances of the BOA and rival algorithms to assess the significance of the BOA’s superiority from a statistical perspective. The Wilcoxon signed-rank test [80], a non-parametric test for matched or paired data, was employed for this purpose. This test helps determine whether there is a significant difference between the averages of two data samples. The results of the Wilcoxon signed-rank test, presented in Table 4, indicate instances where the BOA exhibits statistically significant superiority over the respective competing algorithms, with a p-value criterion of less than 0.05.

Table 4.

Wilcoxon signed-rank test results.

Compared Algorithm Objective Function Type
CEC 2017
BOA vs. WSO 1.97E-21
BOA vs. AVOA 3.77E-19
BOA vs. RSA 1.97E-21
BOA vs. MPA 2.00E-18
BOA vs. TSA 9.50E-21
BOA vs. WOA 9.50E-21
BOA vs. MVO 9.03E-19
BOA vs. GWO 5.23E-21
BOA vs. TLBO 3.69E-21
BOA vs. GSA 1.60E-18
BOA vs. PSO 1.54E-19
BOA vs. GA 2.71E-19

4.4. Discussion

In this subsection, the performance of the BOA compared to competing algorithms is discussed. The CEC 2017 test suite has different types of objective functions.

Unimodal functions C17-F1 and C17-F3 have only one main optimum (i.e., global optimum), and for that reason they are suitable criteria for measuring the exploitation ability of metaheuristic algorithms. Analysis of the simulation results shows that the proposed BOA approach, with a strong performance in local search, has superior performance against all twelve competing algorithms for handling unimodal functions. Therefore, as the first strength, the superiority of the BOA in exploitation is confirmed against competing algorithms.

Multimodal functions C17-F4 to C17-F10, in addition to the main optimum (i.e., the global optimum), also have a number of local optima, which challenge the exploration ability of metaheuristic algorithms. The findings obtained from the simulation results show that the BOA, with global search management, was able to achieve the rank of the best optimizer in the competition with the compared algorithms to handle the functions C17-F4 to C17-F10. The simulation results confirm that, as the second strength, the BOA has a better exploration ability to manage global search compared to competing algorithms.

Hybrid functions C17-F11 to C17-F20 and composition functions C17-F21 to C17-F30 are complex optimization problems that challenge the performance of metaheuristic algorithms in establishing a balance between exploration and exploitation. The simulation results of these functions show that the BOA was able to achieve the rank of the best optimizer in most of these benchmark functions, except for C17-F22, C17-F25, and C17-F26. The simulation results confirm that the BOA is highly capable of balancing exploration and exploitation when facing complex optimization problems. Therefore, as a third strength, the superiority of the BOA in balancing exploration and exploitation is confirmed compared to competing algorithms.

In addition, the statistical analysis of the Wilcoxon signed-rank test and the values obtained for the p-value index, as the fourth strength, confirm that the BOA has a significant statistical superiority compared to all twelve competing algorithms.

5. BOA for Real-World Applications

In this section, the effectiveness of the proposed BOA approach in addressing real-world optimization tasks is evaluated. To this end, twenty-two constrained optimization problems from the CEC 2011 test suite, along with four engineering design problems, are utilized.

5.1. Evaluation of CEC 2011 Test Suite

In this subsection, the performance of the BOA in optimizing the CEC 2011 test suite, which comprises twenty-two constrained optimization problems from real-world applications, is assessed. Detailed descriptions and information about the CEC 2011 test suite can be found in [81]. The results of employing the BOA and competing algorithms on the CEC 2011 test suite are presented in Table 5, and the boxplot diagrams illustrating the performance of the BOA and competing algorithms are depicted in Figure 5. The optimization outcomes highlight that the BOA effectively generated suitable solutions for this test suite, showcasing a balanced exploration and exploitation throughout the search process. Notably, the BOA emerges as the top optimizer for solving functions C11-F1 to C11-F22, demonstrating superior performance in comparison to competing algorithms. Statistical analysis, specifically the Wilcoxon signed-rank test, further validates the significant statistical superiority of the BOA in these evaluations.

Table 5.

Optimization results of the CEC 2011 test suite.

BOA WSO AVOA RSA MPA TSA WOA MVO GWO TLBO GSA PSO GA
C11-F1 Mean 5.920103 18.3658 13.36522 22.89003 7.662645 19.13919 13.67372 14.47026 11.14773 19.17297 22.59503 18.65142 24.38586
Best 2E-10 16.19408 9.345854 21.25619 0.392096 18.18294 8.678559 11.68925 1.176288 17.33253 20.70269 11.03757 23.48431
Worst 12.30606 21.05886 17.2206 25.24276 12.70674 20.36399 17.69423 16.92367 18.35369 21.06058 23.95826 24.97436 26.34835
Std 7.196379 2.475039 4.55974 1.997624 5.912131 1.046045 4.319552 2.53189 7.606047 1.629171 1.471501 6.959545 1.418008
Median 5.687176 18.10514 13.44722 22.53059 8.775874 19.00491 14.16104 14.63406 12.53047 19.14939 22.85957 19.29688 23.85539
Rank 1 7 4 12 2 9 5 6 3 10 11 8 13
C11-F2 Mean −26.3179 −13.8385 −20.8022 −10.8912 −25.0347 −10.5975 −18.2689 −7.99707 −22.4684 −10.1862 −15.0459 −22.5196 −12.3132
Best −27.0676 −15.2725 −21.3417 −11.3546 −25.6818 −14.5354 −21.8709 −10.1042 −24.6938 −11.4086 −20.3083 −23.9159 −14.7797
Worst −25.4328 −12.5692 −20.0389 −10.403 −23.6635 −8.29419 −14.0672 −6.404 −18.7253 −9.11933 −10.7963 −20.0088 −10.5245
Std 0.738935 1.450672 0.613406 0.51655 0.987822 3.104455 4.221461 1.682368 2.761006 0.998848 4.557654 1.808243 2.093573
Median −26.3856 −13.7562 −20.914 −10.9036 −25.3968 −9.78013 −18.5688 −7.74007 −23.2272 −10.1085 −14.5394 −23.0768 −11.9743
Rank 1 8 5 10 2 11 6 13 4 12 7 3 9
C11-F4 Mean 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05
Best 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05
Worst 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05
Std 2E-19 2.29E-11 2.63E-09 5.16E-11 1.28E-15 2.46E-14 6.39E-19 1.03E-12 3.85E-15 8.1E-14 2.07E-19 6.03E-20 2.85E-18
Median 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05 1.15E-05
Rank 1 11 13 12 6 8 4 10 7 9 3 2 5
C11-F4 Mean 0 0 0 0 0 0 0 0 0 0 0 0 0
Best 0 0 0 0 0 0 0 0 0 0 0 0 0
Worst 0 0 0 0 0 0 0 0 0 0 0 0 0
Std 0 0 0 0 0 0 0 0 0 0 0 0 0
Median 0 0 0 0 0 0 0 0 0 0 0 0 0
Rank 1 1 1 1 1 1 1 1 1 1 1 1 1
C11-F5 Mean −34.1274 −24.4632 −27.8918 −19.4252 −33.246 −26.8779 −27.396 −26.7327 −31.4832 −9.86988 −27.1031 −7.61915 −8.51327
Best −34.7494 −25.646 −28.9861 −21.6476 −33.8296 −31.4861 −27.5536 −31.6474 −34.2023 −12.1106 −31.4408 −11.318 −10.0071
Worst −33.3862 −23.4985 −27.4102 −16.9763 −31.872 −21.3206 −27.0038 −24.211 −27.3029 −8.15331 −23.8495 −5.81752 −6.75594
Std 0.589989 0.989457 0.779829 2.589014 0.96747 4.401075 0.27604 3.659252 3.096495 1.770206 3.496342 2.723063 1.505232
Median −34.1871 −24.3541 −27.5855 −19.5384 −33.6412 −27.3525 −27.5132 −25.5362 −32.2137 −9.60779 −26.561 −6.67054 −8.64499
Rank 1 9 4 10 2 7 5 8 3 11 6 13 12
C11-F6 Mean −24.1119 −13.6555 −18.847 −12.6221 −22.5646 −6.92131 −19.8051 −8.96998 −19.4699 −1.47492 −21.8112 −2.37518 −3.31781
Best −27.4298 −14.2972 −20.1867 −13.3562 −25.6947 −16.2979 −22.9894 −17.2225 −22.2246 −1.67787 −26.7438 −5.2789 −8.77883
Worst −23.0059 −13.3329 −17.0321 −11.6073 −21.2709 −3.56713 −12.5777 −1.40727 −17.8008 −1.40727 −17.4414 −1.40727 −1.40727
Std 2.324951 0.457816 1.549487 0.868125 2.224729 6.579278 5.181926 9.043209 2.229771 0.142217 4.201888 2.034739 3.829068
Median −23.0059 −13.496 −19.0847 −12.7624 −21.6463 −3.9101 −21.8266 −8.62506 −18.9272 −1.40727 −21.5297 −1.40727 −1.54257
Rank 1 7 6 8 2 10 4 9 5 13 3 12 11
C11-F7 Mean 0.860699 1.630336 1.297839 1.954375 0.931882 1.316263 1.772373 0.881731 1.074249 1.746626 1.086692 1.132047 1.769103
Best 0.582266 1.576312 1.151917 1.700334 0.76299 1.146539 1.652665 0.811995 0.807742 1.544826 0.894221 0.827051 1.374402
Worst 1.025027 1.738867 1.439848 2.140834 1.012213 1.688543 1.946221 0.958962 1.308118 1.888265 1.294407 1.382585 1.976253
Std 0.211503 0.078973 0.161247 0.194066 0.121385 0.263306 0.131457 0.078602 0.217578 0.157566 0.191475 0.30478 0.286366
Median 0.91775 1.603082 1.299796 1.988165 0.976163 1.214985 1.745302 0.877984 1.090569 1.776707 1.079071 1.159275 1.862878
Rank 1 9 7 13 3 8 12 2 4 10 5 6 11
C11-F8 Mean 220 287.3329 241.2176 329.2094 222.5348 258.6563 267.7395 224.2247 227.6045 224.2247 247.3067 478.5826 222.5818
Best 220 259.8815 223.7553 286.7508 220 220 246.1934 220 220 220 220 249.1037 220
Worst 220 323.3464 258.6798 375.4703 225.0697 359.4163 315.479 236.8989 235.209 236.8989 296.0452 582.7551 230.3271
Std 0 29.20661 15.7971 38.25039 3.076552 71.0069 33.71364 8.881242 9.229657 8.881242 37.90414 165.984 5.427425
Median 220 283.0518 241.2176 327.3083 222.5348 227.6045 254.6428 220 227.6045 220 236.5908 541.2357 220
Rank 1 10 6 11 2 8 9 4 5 4 7 12 3
C11-F9 Mean 8789.286 577,676.6 392,136.4 1,101,221 20,625 68,367.45 388,333.6 138,018.7 44,296.44 423,556.8 853,670.6 1,122,447 2,014,720
Best 5457.674 385,879.1 346,854.4 718,850 11,156.31 49,109.4 214,821.2 78,052.73 18,844.04 350,374.3 730,315.2 900,965.2 1,930,602
Worst 14,042.29 663,904.2 422,189.5 1,292,119 29,564.96 86,903.2 658,126.8 208,994.3 77,779.54 543,358.7 919,076.4 1,374,733 2,132,738
Std 3889.181 137,784.3 34,745.74 273,210.9 8526.786 16,900.77 212,512.5 56,771.19 26,179.21 89,242.55 88,329.7 266,242.6 104,535.7
Median 7828.591 630,461.6 399,750.8 1,196,958 20,889.37 68,728.59 340,193.1 132,513.8 40,281.09 400,247.2 882,645.4 1,107,045 1,997,771
Rank 1 9 7 11 2 4 6 5 3 8 10 12 13
C11-F10 Mean −21.4889 −13.701 −16.7579 −11.948 −18.9391 −14.1356 −12.564 −14.4587 −13.8394 −10.9206 −12.8545 −11.024 −10.7178
Best −21.8299 −14.9479 −16.9487 −12.3376 −19.3304 −18.7599 −13.2827 −21.164 −14.3313 −11.0122 −13.3834 −11.0692 −10.7552
Worst −20.7878 −13.0631 −16.3898 −11.6609 −18.554 −11.6783 −12.0574 −11.0939 −12.6316 −10.8456 −12.0435 −11.0025 −10.6622
Std 0.498616 0.900402 0.26946 0.303776 0.42259 3.348581 0.542185 4.773199 0.85429 0.076044 0.682286 0.032754 0.042033
Median −21.669 −13.3964 −16.8466 −11.8967 −18.936 −13.0521 −12.4579 −12.7884 −14.1973 −10.9123 −12.9956 −11.0121 −10.7269
Rank 1 7 3 10 2 5 9 4 6 12 8 11 13
C11-F11 Mean 571,712.3 5,990,542 1,005,937 9,157,615 1,697,924 6,138,051 1,238,362 1,334,588 3,950,347 5,376,638 1,441,156 5,388,114 6,322,408
Best 260,837.9 5,713,697 790,621.8 8,861,897 1,582,223 5,108,653 1,126,726 609,492 3,753,138 5,357,622 1,292,303 5,372,054 6,288,702
Worst 828,560.9 6,367,119 1,183,769 9,345,099 1,828,453 7,420,263 1,396,911 2,812,910 4,332,212 5,392,350 1,619,216 5,407,480 6,399,460
Std 260,922.1 315,719.1 180,244.7 217,528.6 122,969.1 1,003,762 119,865 1,050,363 273,781 15,960.55 141,558.1 16,144.36 55,013.89
Median 598,725.2 5,940,676 1,024,678 9,211,733 1,690,509 6,011,644 1,214,905 957,974.7 3,858,018 5,378,291 1,426,551 5,386,462 6,300,734
Rank 1 10 2 13 6 11 3 4 7 8 5 9 12
C11-F12 Mean 1,199,805 8,648,465 3,453,394 13,667,035 1,277,229 5,166,688 5,980,120 1,332,009 1,432,076 14,799,181 5,954,053 2,353,727 14,965,863
Best 1,155,937 8,290,445 3,348,644 12,692,541 1,199,938 4,885,754 5,545,813 1,174,160 1,263,209 13,925,728 5,653,564 2,175,729 14,835,162
Worst 1,249,353 8,965,661 3,521,972 14,523,280 1,357,501 5,316,545 6,197,392 1,482,783 1,573,795 15,476,182 6,170,450 2,571,333 15,100,976
Std 47,157.58 294,829.2 79,624.52 789,278.6 72,305.18 210,271.9 315,606 132,531.8 135,346.5 683,800.8 234,270.3 171,464.7 114,159.5
Median 1,196,965 8,668,878 3,471,481 13,726,159 1,275,738 5,232,227 6,088,637 1,335,547 1,445,649 14,897,407 5,996,098 2,333,922 14,963,658
Rank 1 10 6 11 2 7 9 3 4 12 8 5 13
C11-F13 Mean 15,444.2 15,872.72 15,448.13 16,341.93 15,463.86 15,491.87 15,538.8 15,510.22 15,503.18 15,951.03 132,457.9 15,492.53 30,533.99
Best 15,444.19 15,680.46 15,447.1 15,910.59 15,461.47 15,481.59 15,493.51 15,489.25 15,496 15,634.2 95,600.27 15,474.67 15,461.05
Worst 15,444.21 16,338.51 15,449.28 17,413.55 15,468 15,504.94 15,599.85 15,550.13 15,515.6 16,534.68 182,449.7 15,530.38 75,388.3
Std 0.009091 329.5679 0.965292 757.1036 3.04201 12.13496 52.00076 29.66598 9.128434 428.3972 41,099.67 26.81114 31,431.06
Median 15,444.2 15,735.95 15,448.08 16,021.78 15,462.99 15,490.47 15,530.92 15,500.75 15,500.56 15,817.61 125,890.8 15,482.53 15,643.31
Rank 1 9 2 11 3 4 8 7 6 10 13 5 12
C11-F14 Mean 18,295.35 115,938.6 18,527.59 236,838 18,619.25 19,576.66 19,259.86 19,460.62 19,267.06 321,549.6 19,121.96 19,155.72 19,142.49
Best 18,241.58 88,038.86 18,409.22 174,242.1 18,533.36 19,310.27 19,102.02 19,357.41 19,116.91 30,687.52 18,822.08 18,985.66 18,847.36
Worst 18,388.08 162,435.6 18,626.34 341,619.3 18,694.96 20,146.79 19,385.69 19,546.24 19,460.5 621,276.2 19,341.44 19,304.28 19,454.19
Std 71.59938 34,977.03 107.5807 78,804.57 73.40623 403.5767 136.4873 83.23058 159.3053 298,019.5 235.5233 137.423 260.6657
Median 18,275.87 106,639.9 18,537.4 215,745.3 18,624.35 19,424.79 19,275.87 19,469.41 19,245.42 317,117.3 19,162.17 19,166.47 19,134.21
Rank 1 11 2 12 3 10 7 9 8 13 4 6 5
C11-F15 Mean 32,883.58 940,841.1 110,645.3 1,985,231 32,950.76 55,363.33 225,557.8 33,108.08 33,085.12 15,996,211 309,756.9 33,303.15 8,231,969
Best 32,782.17 387,070.3 43,553.37 829,509.7 32,873.13 33,051.11 33,017.86 33,024.19 33,048.03 3,350,790 274,007.7 33,293.78 3,746,244
Worst 32,956.46 2,367,653 185,709.1 5,184,170 33,020.99 121,996.9 323,378.9 33,169.01 33,150.04 23,854,606 334,233.8 33,312.43 14,108,888
Std 76.94696 1,003,433 80,304.62 2,245,091 63.64504 46,692.58 137,782.2 67.04471 48.92391 9,799,500 29,448.29 8.071454 4,994,206
Median 32,897.86 504,320.5 106,659.4 963,621.3 32,954.47 33,202.65 272,917.2 33,119.57 33,071.21 18,389,724 315,393.1 33,303.19 7,536,372
Rank 1 10 7 11 2 6 8 4 3 13 9 5 12
C11-F16 Mean 133,550 975,518.1 135,237.7 2,017,200 137,810.6 145,558 142,484.5 142,115.8 146,331.8 92,220,903 19,417,718 82,541,543 79,253,422
Best 131,374.2 294,692.9 133,737.1 486,424.7 135,730.3 142,830.3 136,399.6 133,165.5 143,684 89,866,744 9,860,015 68,276,866 64,052,715
Worst 136,310.8 2,311,282 135,911.9 5,020,540 141,530.1 147,640.7 147,906.6 151,316.2 151,968.7 94,876,220 35,135,215 98,635,651 1.01E+08
Std 2392.2 953,315.1 1067.526 2,143,364 2722.974 2482.867 5054.284 8022.252 4005.458 2,206,781 11,487,547 13,754,292 16,662,950
Median 133,257.5 648,048.9 135,650.9 1,280,917 136,991 145,880.4 142,816 141,990.7 144,837.2 92,070,325 16,337,822 81,626,828 75,794,234
Rank 1 8 2 9 3 6 5 4 7 13 10 12 11
C11-F17 Mean 1,926,615 9.3E+09 2.4E+09 1.61E+10 2,304,570 1.33E+09 1.01E+10 3,156,432 3,060,480 2.31E+10 1.16E+10 2.16E+10 2.27E+10
Best 1,916,953 7.92E+09 2.18E+09 1.16E+10 1,958,863 1.1E+09 7.18E+09 2,310,026 2,042,683 2.23E+10 1.02E+10 1.91E+10 2.12E+10
Worst 1,942,685 1.03E+10 2.63E+09 1.97E+10 2,944,065 1.52E+09 1.34E+10 3,810,703 4,991,555 2.42E+10 1.23E+10 2.5E+10 2.56E+10
Std 12,003.53 1.11E+09 2.07E+08 3.66E+09 464,536.3 2.29E+08 2.74E+09 728,055.4 1,396,444 8.21E+08 9.97E+08 2.8E+09 2.11E+09
Median 1,923,412 9.48E+09 2.4E+09 1.66E+10 2,157,676 1.35E+09 9.84E+09 3,252,498 2,603,840 2.31E+10 1.2E+10 2.12E+10 2.2E+10
Rank 1 7 6 10 2 5 8 4 3 13 9 11 12
C11-F18 Mean 942,057.5 57,009,339 6,765,597 1.23E+08 972,857.5 2,091,646 9,903,113 989,837.6 1,034,458 32,127,447 11,509,537 1.4E+08 1.19E+08
Best 938,416.2 39,198,119 4,054,026 84,796,562 950,200.1 1,824,897 4,240,455 964,629.7 967,922.6 25,456,959 8,580,056 1.17E+08 1.14E+08
Worst 944,706.9 64,852,362 11,629,143 1.4E+08 1,033,181 2,447,367 17,411,962 1,001,598 1,210,129 34,756,120 14,528,317 1.55E+08 1.23E+08
Std 2774.139 12,627,720 3,707,867 27,267,025 42,401.09 315,442.7 5,845,999 17,904.23 123,353.4 4,693,486 2,793,344 17,827,026 3,754,354
Median 942,553.5 61,993,438 5,689,610 1.33E+08 954,024.6 2,047,161 8,980,017 996,561.4 979,889.4 34,148,355 11,464,888 1.43E+08 1.19E+08
Rank 1 10 6 12 2 5 7 3 4 9 8 13 11
C11-F19 Mean 1,025,341 56,112,190 6,867,491 1.2E+08 1,142,037 2,517,276 10,562,701 1,493,568 1,375,430 36,886,795 6,463,721 1.79E+08 1.19E+08
Best 967,927.7 47,875,067 6,260,767 1.04E+08 1,070,955 2,270,154 2,100,547 1,134,176 1,241,437 25,821,500 2,432,836 1.63E+08 1.16E+08
Worst 1,167,142 71,354,860 8,329,100 1.51E+08 1,297,605 2,980,670 19,167,084 1,996,238 1,558,531 46,022,778 8,501,596 2.07E+08 1.23E+08
Std 99,675.04 11,137,193 1,031,447 23,175,948 110,088.2 333,115.4 8,443,038 380,000.6 139,424 9,198,239 2,895,913 20,333,979 2,808,423
Median 983,146.6 52,609,416 6,440,048 1.13E+08 1,099,794 2,409,140 10,491,585 1,421,928 1,350,877 37,851,450 7,460,226 1.73E+08 1.19E+08
Rank 1 10 7 12 2 5 8 4 3 9 6 13 11
C11-F20 Mean 941,250.4 59,668,611 6,078,019 1.3E+08 961,061.9 1,859,713 7,518,662 973,995.9 1,000,685 35,832,144 14,770,447 1.65E+08 1.2E+08
Best 936,143.2 52,493,138 5,354,905 1.14E+08 957,468.7 1,668,863 7,081,933 963,584.3 978,672.9 35,045,378 9,799,344 1.51E+08 1.14E+08
Worst 946,866.6 70,665,769 6,851,445 1.55E+08 963,379.7 2,176,763 8,101,614 985,820.9 1,017,853 36,682,873 22,883,459 1.79E+08 1.24E+08
Std 5013.552 8,139,325 652,894.4 18,267,776 2670.851 253,461.5 458,251.8 10,320.56 17,752.81 715,894.6 6,010,182 16,641,832 4,510,598
Median 940,995.9 57,757,768 6,052,862 1.26E+08 961,699.6 1,796,612 7,445,551 973,289.1 1,003,107 35,800,163 13,199,493 1.65E+08 1.2E+08
Rank 1 10 6 12 2 5 7 3 4 9 8 13 11
C11-F21 Mean 12.71443 51.66477 21.98088 78.87305 16.0572 30.47192 39.77733 28.09829 22.74275 104.0164 41.7608 109.2417 105.994
Best 9.974206 42.34744 20.68456 58.47624 13.90111 27.01848 36.26677 24.84148 20.91572 49.63025 36.61142 94.29664 60.45563
Worst 14.97499 61.65781 23.79304 99.26551 18.3479 32.19298 44.13805 31.18011 25.09372 153.4827 44.73996 121.6858 129.6288
Std 2.412667 8.750969 1.396524 18.93558 2.173182 2.482172 3.658371 3.733097 1.924417 44.71405 3.837542 14.11278 33.81205
Median 12.95425 51.32692 21.72295 78.87522 15.98989 31.33811 39.35224 28.18579 22.48077 106.4764 42.84591 110.4922 116.9458
Rank 1 9 3 10 2 6 7 5 4 11 8 13 12
C11-F22 Mean 16.12513 47.98 27.87551 65.28358 19.19349 32.74598 47.48138 32.90803 25.33021 105.8946 47.85216 110.0809 95.48389
Best 11.50133 41.46275 22.5794 46.99819 16.36546 28.71428 41.10402 25.17317 24.09788 68.38003 39.74339 92.35913 94.65695
Worst 19.55286 53.63684 33.24577 75.15155 21.32566 35.26266 52.30679 38.08284 26.25798 125.4222 57.19442 121.509 97.01353
Std 4.197797 5.483258 5.290419 13.16113 2.482115 2.995329 5.301012 6.106807 1.080977 26.96416 7.537477 13.85053 1.132853
Median 16.72317 48.41021 27.83842 69.4923 19.54142 33.50349 48.25735 34.18806 25.48249 114.8881 47.23541 113.2277 95.13255
Rank 1 9 4 10 2 5 7 6 3 12 8 13 11
Sum rank 22 191 109 231 55 146 145 118 97 222 157 198 224
Mean rank 1 8.681818 4.954545 10.5 2.5 6.636364 6.590909 5.363636 4.409091 10.09091 7.136364 9 10.18182
Total rank 1 9 4 13 2 7 6 5 3 11 8 10 12
Wilcoxon: p-value 4.38E-12 7.75E-15 1.56E-15 0.001746142 4.89E-15 5.25E-15 1.60E-11 1.92E-12 3.34E-15 8.03E-15 1.56E-15 2.28E-15

Figure 5.

Figure 5

Figure 5

Boxplot diagrams of the BOA and competing algorithms’ performances on the CEC 2011 test suite.

5.2. Pressure Vessel Design Problem

The design of the pressure vessel in engineering aims primarily to minimize construction costs, as illustrated in Figure 6. The mathematical representation of pressure vessel design is defined as follows [82]:

Figure 6.

Figure 6

Schematic of pressure vessel design. The thickness of the shell is Ts, the thickness of the head is Th, the length of cylindrical shell is L, and the inner radius is R.

Consider: X=x1,x2,x3,x4=Ts,Th,R,L.

Minimize: fx=0.6224x1x3x4+1.778x2x32+3.1661x12x4+19.84x12x3.

Subject to

g1x=x1+0.0193x3  0, g2x=x2+0.00954x3 0,
g3x=πx32x443πx33+1296000 0, g4x=x4240  0.

with

0x1,x2100 and 10x3,x4200.

The outcomes derived from applying the BOA and rival algorithms to optimize pressure vessel design are documented in Table 6 and Table 7. According to the results, the BOA yielded the optimal solution for this design, with design variable values of (0.7781685, 0.3846492, 40.319615, 200) and an objective function value of 5885.3263. The convergence curve of the BOA throughout the discovery of the optimal solution for pressure vessel design is depicted in Figure 7. Examination of the optimization results indicates that the BOA exhibits superior performance in addressing pressure vessel design challenges, outperforming competing algorithms.

Table 6.

Performance of optimization algorithms on the pressure vessel design problem.

Algorithm Optimal Variables Optimal Cost
Ts Th R L
BOA 0.7781685 0.3846492 40.319615 200 5885.3263
WSO 0.7781685 0.3846492 40.319615 200 5885.3322
AVOA 0.7781902 0.3846599 40.320737 199.98436 5885.3693
RSA 0.8538832 0.4168324 40.384824 200 6547.2433
MPA 0.7781685 0.3846492 40.319615 200 5885.3322
TSA 0.7797576 0.3858656 40.396539 200 5913.0266
WOA 0.8128457 0.5410128 40.396424 198.93351 6581.148
MVO 0.8182022 0.4061992 42.352706 173.53515 5968.7271
GWO 0.7784539 0.3856252 40.32716 199.94288 5890.2366
TLBO 1.1978845 1.2639942 61.056149 91.741579 14,709.571
GSA 0.957018 0.4737273 49.581732 144.99985 7674.4943
PSO 1.276768 2.3221525 50.647017 110.15343 17,231.342
GA 1.1434315 0.7799385 54.784767 96.514991 9745.9413

Table 7.

Statistical results of optimization algorithms on the pressure vessel design problem.

Algorithm Mean Best Worst Std Median Rank
BOA 5885.3263 5885.3263 5885.3263 2.32E-08 5885.3263 1
WSO 5907.011 5885.3322 6094.606 53.104713 5885.3322 3
AVOA 6417.9542 5885.3693 7301.8987 485.20827 6249.9206 5
RSA 12,102.458 6547.2433 20,969.982 3923.6076 11,268.435 9
MPA 5885.3322 5885.3322 5885.3322 3.91E-06 5885.3322 2
TSA 6259.4568 5913.0266 7323.2568 391.18418 6101.1237 6
WOA 7978.5279 6581.148 12,433.242 1390.3395 7795.4774 8
MVO 6576.3819 5968.7271 7273.5044 448.12807 6572.6459 7
GWO 5945.5243 5890.2366 6636.6942 163.66397 5901.7573 4
TLBO 39,032.934 14,709.571 69,674.574 15,506.903 38,454.338 12
GSA 24,592.049 7674.4943 39,531.957 8743.4829 26,413.075 10
PSO 41,176.997 17,231.342 89,983.875 18,842.417 38,677.472 13
GA 29,575.451 9745.9413 60,485.672 14,026.27 26,621.057 11

Figure 7.

Figure 7

The BOA’s performance convergence curve on pressure vessel design.

5.3. Speed Reducer Design Problem

The design of a speed reducer is a practical engineering application focused on minimizing the weight of the speed reducer, as illustrated in Figure 8. The mathematical model for the design of the speed reducer is outlined in [83,84]:

Figure 8.

Figure 8

Schematic of speed reducer design. The face width is b, the number of teeth on the pinion is z, the module of teeth is m, the length of the second shaft between bearings is l2, the length of the first shaft between bearings is l1, the second shaft’s diameter is d2, and the first shaft’s diameter is d1.

Consider: X=x1,x2,x3,x4,x5,x6,x7=b,m,p,l1,l2,d1,d2.

Minimize: fx=0.7854x1x223.3333x32+14.9334x343.09341.508x1x62+x72+7.4777x63+x73+0.7854(x4x62+x5x72).

Subject to

g1x=27x1x22x310,g2x=397.5x1x22x3210,
g3x=1.93x43x2x3x6410,g4x=1.93x53x2x3x7410,
g5x=1110x63745x4x2x32+16.9×10610,
g6(x)=185x73745x5x2x32+157.5×10610,
g7x=x2x34010,g8x=5x2x110,
g9x=x112x210,g10x=1.5x6+1.9x410,
g11x=1.1x7+1.9x510.

with

2.6x13.6,0.7x20.8,17x328,7.3x48.3,7.8x58.3,2.9x63.9, and 5x75.5.

The outcomes of implementing the BOA and competing optimizers to address the speed reducer design challenges are documented in Table 8 and Table 9. The BOA yielded the optimal solution for this design, characterized by design variable values (3.5, 0.7, 17, 7.3, 7.8, 3.3502147, 5.2866832) and an objective function value of 2996.3482. The convergence curve, depicting the BOA’s performance in optimizing the speed reducer design, is illustrated in Figure 9. The analysis of the simulation results confirms that the BOA demonstrated more effective performance in tackling the speed reducer design compared to its competitors.

Table 8.

Performance of optimization algorithms on the speed reducer design problem.

Algorithm Optimal Variables Optimal Cost
b M p l1 l2 d1 d2
BOA 3.5 0.7 17 7.3 7.8 3.3502147 5.2866832 2996.3482
WSO 3.5000005 0.7 17 7.3000099 7.8000004 3.3502148 5.2866833 2996.3483
AVOA 3.5 0.7 17 7.3000007 7.8 3.3502147 5.2866832 2996.3482
RSA 3.5922092 0.7 17 8.222092 8.261046 3.3556658 5.4833809 3182.9113
MPA 3.5 0.7 17 7.3 7.8 3.3502147 5.2866832 2996.3482
TSA 3.5129039 0.7 17 7.3 8.261046 3.3505407 5.2902177 3013.8833
WOA 3.587509 0.7 17 7.3 8.0094193 3.3616163 5.2867558 3038.2679
MVO 3.5022528 0.7 17 7.3 8.069157 3.3696027 5.2868819 3008.2394
GWO 3.5006415 0.7 17 7.3051454 7.8 3.3639533 5.2888109 3001.5161
TLBO 3.556121 0.703999 26.327655 8.1017162 8.1453492 3.6635667 5.3393802 5271.2441
GSA 3.5229197 0.7027544 17.369301 7.8207543 7.8896487 3.4088005 5.3859782 3169.7986
PSO 3.5081873 0.700072 18.096129 7.3990809 7.8680597 3.5955569 5.3440486 3302.6701
GA 3.5780478 0.7055678 17.814174 7.742773 7.8558683 3.7017132 5.3463595 3.35E+03

Table 9.

Statistical results of optimization algorithms on the speed reducer design problem.

Algorithm Mean Best Worst Std Median Rank
BOA 2996.3482 2996.3482 2996.3482 9.33E-13 2996.3482 1
WSO 2996.6318 2996.3483 2998.8003 0.5851051 2996.3644 3
AVOA 3000.8579 2996.3482 3011.0816 3.9697349 3000.7583 4
RSA 3276.9058 3182.9113 3335.2402 57.540902 3291.7902 9
MPA 2996.3482 2996.3482 2996.3482 3.19E-06 2996.3482 2
TSA 3032.1482 3013.8833 3045.8852 10.144159 3033.9369 7
WOA 3150.1207 3038.2679 3445.3098 106.34463 3116.768 8
MVO 3029.8375 3008.2394 3070.2104 13.263239 3030.2775 6
GWO 3004.6252 3001.5161 3010.5926 2.5083807 3004.107 5
TLBO 6.958E+13 5271.2441 5.037E+14 1.158E+14 2.725E+13 12
GSA 3454.8489 3169.7986 4076.1493 262.31973 3325.1431 10
PSO 1.027E+14 3302.6701 5.202E+14 1.24E+14 7.345E+13 13
GA 4.944E+13 3347.0081 3.191E+14 7.789E+13 1.981E+13 11

Figure 9.

Figure 9

The BOA’s performance convergence curve on speed reducer design.

5.4. Welded Beam Design

The design of a welded beam poses a real-world engineering challenge, intending to minimize the fabrication cost of the beam, as depicted in Figure 10. The mathematical model governing the welded beam design is outlined as follows [26]:

Figure 10.

Figure 10

Schematic of welded beam design. The bar height is t, the weld thickness is h, the thickness of bar is b, and the length of clamped bar is l.

Consider: X=x1,x2,x3,x4=h,l,t,b.

Minimize: f(x)=1.10471x12x2+0.04811x3x4(14.0+x2).

Subject to

g1x=τx136000, g2x=σx30000  0,
g3x=x1x4 0, g4(x)=0.10471x12+0.04811x3x4 (14+x2)5.0  0,
g5x=0.125 x1 0, g6x=δ x0.25  0,
g7x=6000pc x 0,

where

τx=τ2+2ττx22R+τ2 , τ=60002x1x2, τ=MRJ,
M=600014+x22, R=x224+x1+x322,
J=2x1x22x2212+x1+x322, σx=504000x4x32, δx=2.1925x4x33,
pc x=17062.0748·x3x431x32858.

with 0.1x1,x42 and 0.1x2,x310.

The optimization outcomes for the welded beam design, utilizing the BOA and competing algorithms, are outlined in Table 10 and Table 11. The BOA yielded the optimal solution for this design, with design variable values set at (0.2057296, 3.4704887, 9.0366239, 0.2057296), resulting in an objective function value of 1.7246798. The convergence process of the BOA towards the optimal solution for the welded beam design is illustrated in Figure 11. The simulation results underscore the effectiveness of the BOA in addressing the welded beam design problem, showcasing superior performance compared to competing algorithms.

Table 10.

Performance of optimization algorithms on the welded beam design problem.

Algorithm Optimal Variables Optimal Cost
h l t b
BOA 0.2057296 3.4704887 9.0366239 0.2057296 1.7246798
WSO 0.2057296 3.4704887 9.0366239 0.2057296 1.7248523
AVOA 0.2049647 3.4870781 9.0365172 0.2057345 1.7259197
RSA 0.1966937 3.534683 9.9249453 0.2177987 1.9754653
MPA 0.2057296 3.4704887 9.0366239 0.2057296 1.7248523
TSA 0.2041956 3.4953797 9.0641911 0.2061564 1.7338449
WOA 0.2137287 3.3297286 8.9738153 0.2209982 1.8213232
MVO 0.2059931 3.46481 9.044686 0.2060556 1.7283648
GWO 0.205592 3.4736454 9.0362401 0.2057988 1.7255236
TLBO 0.315253 4.4215666 6.7977001 0.4250886 3.0235653
GSA 0.2938352 2.7217307 7.4212433 0.3079408 2.0844573
PSO 0.3725304 3.4246823 7.3446854 0.5739303 4.0226813
GA 0.224308 6.9143503 7.7634846 0.304362 2.7608802

Table 11.

Statistical results of optimization algorithms on the welded beam design problem.

Algorithm Mean Best Worst Std Median Rank
BOA 1.7246798 1.7246798 1.7246798 2.28E-16 1.7246798 1
WSO 1.7248526 1.7248523 1.7248578 1.25E-06 1.7248523 3
AVOA 1.7612095 1.7259197 1.8426669 0.0364639 1.7473196 7
RSA 2.1815628 1.9754653 2.5291486 0.1441236 2.1565285 8
MPA 1.7248523 1.7248523 1.7248523 3.35E-09 1.7248523 2
TSA 1.7431468 1.7338449 1.7523381 0.005605 1.743243 6
WOA 2.3106389 1.8213232 4.0458397 0.6416317 2.0857253 9
MVO 1.7412206 1.7283648 1.775042 0.0137552 1.7371509 5
GWO 1.7272522 1.7255236 1.7312956 0.0013626 1.727007 4
TLBO 3.326E+13 3.0235653 3.209E+14 8.111E+13 5.6909484 12
GSA 2.4436073 2.0844573 2.7521417 0.1914907 2.4731468 10
PSO 4.586E+13 4.0226813 2.776E+14 8.759E+13 6.7293081 13
GA 1.126E+13 2.7608802 1.218E+14 3.456E+13 5.6575496 11

Figure 11.

Figure 11

The BOA’s performance convergence curve on welded beam design.

5.5. Tension/Compression Spring Design Problem

The engineering challenge in tension/compression spring design is to minimize the weight of the spring, as depicted in Figure 12. The mathematical model for tension/compression spring design is outlined as follows [26]:

Figure 12.

Figure 12

Schematic of tension/compression spring design. The wire’s diameter is d, the number of active coils is P, and the mean coil’s diameter is D.

Consider: X=x1,x2,x3=d,D,P.

Minimizefx=x3+2x2x12.

Subject to

g1x=1x23x371785x14  0, g2x=4x22x1x212566(x2x13)+15108x121 0,
g3x=1140.45x1x22x3 0, g4x=x1+x21.51  0.

with 0.05x12,0.25x21.3 and 2x315.

The optimization outcomes for tension/compression spring design using the BOA and competing algorithms are outlined in Table 12 and Table 13. The BOA yielded the optimal solution for this design, with design variable values of (0.0516891, 0.3567177, 11.288966) and an objective function value of 0.0126019. The convergence curve depicting the BOA’s performance in optimizing the tension/compression spring design is illustrated in Figure 13. The simulation results demonstrate that the BOA exhibited superior performance compared to competing algorithms by delivering improved outcomes for tension/compression spring design.

Table 12.

Performance of optimization algorithms on the tension/compression spring design problem.

Algorithm Optimal Variables Optimal Cost
d D P
BOA 0.0516891 0.3567177 11.288966 0.0126019
WSO 0.0516871 0.3566701 11.291759 0.0126652
AVOA 0.0511918 0.3448817 12.021301 0.0126702
RSA 0.0501316 0.314172 14.710881 0.0131579
MPA 0.0516907 0.3567583 11.28659 0.0126652
TSA 0.0509889 0.3401015 12.347641 0.012682
WOA 0.0511663 0.3442823 12.06054 0.0126707
MVO 0.0501316 0.3199667 13.884692 0.0127497
GWO 0.0519561 0.3631596 10.925567 0.0126707
TLBO 0.0677281 0.8916127 2.7236846 0.0174771
GSA 0.0551098 0.4411042 7.8215101 0.0130734
PSO 0.0676458 0.8885012 2.7236846 0.0173752
GA 0.0681952 0.8994084 2.7236846 0.0178708

Table 13.

Statistical results of optimization algorithms on the tension/compression spring design problem.

Algorithm Mean Best Worst Std Median Rank
BOA 0.0126019 0.0126019 0.0126019 6.88E-18 0.0126019 1
WSO 0.0126763 0.0126652 0.0128239 3.537E-05 0.0126656 3
AVOA 0.0133339 0.0126702 0.0141329 0.00055 0.0132665 8
RSA 0.0132385 0.0131579 0.0133806 6.845E-05 0.0132178 6
MPA 0.0126652 0.0126652 0.0126652 2.81E-09 0.0126652 2
TSA 0.0129585 0.012682 0.0135147 0.0002383 0.0128858 5
WOA 0.0132643 0.0126707 0.0144745 0.0005961 0.0130687 7
MVO 0.0164236 0.0127497 0.0178419 0.0016251 0.0173272 9
GWO 0.0127222 0.0126707 0.0129425 5.456E-05 0.0127197 4
TLBO 0.0180015 0.0174771 0.0186004 0.0003532 0.0179579 10
GSA 0.0193335 0.0130734 0.031807 0.0042027 0.0189131 11
PSO 2.064E+13 0.0173752 3.663E+14 8.195E+13 0.0173752 13
GA 1.612E+12 0.0178708 1.668E+13 4.815E+12 0.025383 12

Figure 13.

Figure 13

The BOA’s performance convergence curve on tension/compression spring design.

6. Conclusions and Future Works

In this paper, motivated by the No Free Lunch (NFL) theorem, a new human-based metaheuristic algorithm called the Botox Optimization Algorithm (BOA) was introduced, mimicking the human action of Botox injections. The originality of the proposed BOA approach was confirmed based on the best knowledge obtained from the literature review, where no metaheuristic algorithm based on Botox injection modeling has been designed so far. The fundamental inspiration of the BOA is the injection of Botox into the areas of the face in order to remove defects from the face and increase facial beauty. The theory of the BOA was stated, and the various stages of its implementation were mathematically modeled based on the simulation of Botox injection. The performance of the BOA was evaluated on the CEC 2017 test suite. The optimization results showed that the BOA has a high ability to balance exploration and exploitation during the search process. To measure the quality of the BOA, the obtained results were compared with the performance of twelve well-known metaheuristic algorithms. The simulation results showed that the BOA outperformed competing algorithms by providing better results in most benchmark functions. Using statistical analysis, it was shown that the BOA has significant statistical superiority over competing algorithms. Also, the implementation of the BOA on twenty-two constrained optimization problems from the CEC 2011 test suite showed the ability of the proposed approach to handle real-world applications.

After introducing the proposed BOA approach, several research paths can be considered for further studies:

  • Binary BOA: The real version of the BOA is detailed and explained thoroughly in this paper. Nonetheless, many scientific optimization issues, like feature selection, require the use of binary versions of metaheuristic algorithms for efficient optimization. Consequently, developing the binary version of the BOA (BBOA) is a notable focus of this research.

  • Multi-objective BOA: Optimization problems are classified based on the number of objective functions, which are either single-objective or multi-objective. To find an optimal solution, many problems require the consideration of multiple objective functions simultaneously. Hence, exploring the potential of developing a multi-objective version of the BOA (MOBOA) to address multi-objective optimization dilemmas is another area of research highlighted in this paper.

  • Hybrid BOA: Researchers have always been intrigued by the idea of merging multiple metaheuristic algorithms to leverage the strengths of each and establish a more efficient hybrid strategy. Hence, a potential future research endeavor includes crafting hybrid versions of the BOA.

  • Tackle new domains: Exploring opportunities for employing the BOA in tackling practical applications and optimizing problems within various scientific fields, like robotics, renewable energy, chemical engineering, and image processing, is a focus for future research proposals.

Acknowledgments

The authors thank the University of Hradec Králové for its support.

Author Contributions

Conceptualization, P.T. and Š.H.; data curation, M.H. and Š.H.; formal analysis, M.H.; investigation, M.H. and Š.H.; methodology, P.T. and Š.H.; software, Š.H.; validation, P.T. and M.H.; visualization, M.H. and Š.H.; writing—original draft preparation, P.T. and M.H.; writing—review and editing M.H. and Š.H. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are contained within the article.

Conflicts of Interest

The authors declare no conflicts of interest.

Funding Statement

This study was supported by the specific research project FacEdu 2024 No. 2126 of the Faculty of Education, University of Hradec Králové.

Footnotes

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