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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>September</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Methods of Parametric Identification Based on Monkey Behavior</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Eugene Fedorov</string-name>
          <email>y.fedorov@chdtu.edu.ua</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Anait Karapetyan</string-name>
          <email>anait.r.karapetyan@gmail.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Kostiantyn Rudakov</string-name>
          <email>k.rudakov@chdtu.edu.ua</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Anatolii Chepynoha</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Cherkasy State Technological University</institution>
          ,
          <addr-line>Cherkasy, Shevchenko blvd., 460, 18006</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2023</year>
      </pub-date>
      <volume>2</volume>
      <fpage>7</fpage>
      <lpage>28</lpage>
      <abstract>
        <p>In modern conditions, a relevant task is the development of methods for the parametric identification of models of artificial neural networks used in intelligent computer systems. To enhance the effectiveness of parametric identification, metaheuristic methods based on monkey behavior (Monkey Search, Monkey Algorithm, Spider Monkey Optimization) have been proposed. These metaheuristic methods use dynamic parameters to ensure global search in the initial iterations and local search in the final iterations, which improves the accuracy of the search and does not require the transformation of the objective function. The proposed metaheuristics expand the application domain of monkey-based parametric identification methods and contribute to the improvement of the efficiency of intelligent computer systems. Further research perspectives include exploring the proposed methods for a wide range of artificial intelligence tasks.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Metaheuristics, monkey search with dynamic parameters, monkey algorithm with dynamic
parameters, spider
monkey
optimization
with
dynamic parameters, and parametric
identification of artificial neural network models</p>
    </sec>
    <sec id="sec-2">
      <title>1. Introduction</title>
      <p>In modern conditions, the development of methods for the parametric identification of artificial
neural network models used in intelligent computer systems [1-3] is an urgent task.</p>
      <p>However, existing parametric identification methods that obtain approximate solutions through
global search do not guarantee convergence, while methods that obtain approximate solutions through
local search have a high probability of getting trapped in local optima. Furthermore, methods that obtain
exact solutions have high computational complexity. Thus, there is a problem of insufficient efficiency
in existing parametric identification methods.</p>
      <p>To reduce the probability of getting stuck in a local extremum and to speed up parametric
identification, modern heuristics (or</p>
      <p>metaheuristics) are used [4-5]. Metaheuristics expand the
possibilities of heuristics by combining heuristic methods based on a high-level strategy [6-7].
Metaheuristics often use the behavior of one or a group of animals [8-9]. Metaheuristics are an
approximate and usually non-deterministic method [10-11]. Advanced metaheuristics use experience
accumulated during the search, represented in memory, to manage the search process [12-13].</p>
      <p>Object of research: The process of parametric identification of an artificial neural network model.
Subject of research: Methods of parametric identification of an artificial neural network model based
on metaheuristics. This work aims to enhance the efficiency of the parametric identification of an
artificial neural network model using metaheuristic methods with dynamic parameters based on the
behavior of monkeys. To achieve the stated objective, the following tasks need to be addressed:</p>
      <p>To develop a numerical optimization method based on the synthesis of the monkey search
algorithm.
ORCID:
0000-0002-7412-3252</p>
      <p>(A. Karapetyan); 0000-0003-3841-7373 (E. Fedorov); 0000-0003-0000-6077 (K. Rudakov);
️©</p>
      <p>2023 Copyright for this paper by its authors.
2. To develop a numerical optimization method based on the synthesis of the monkey algorithm.
3. To develop a numerical optimization method based on the synthesis of the spider monkey
optimization algorithm.</p>
      <p>4. Conduct a numerical investigation of the proposed optimization methods.</p>
    </sec>
    <sec id="sec-3">
      <title>2. Literature Review</title>
      <p>Existing metaheuristics are categorized into non-nature-inspired, evolutionary, immune, biological,
physical, chemical, mathematical, and social. Almost all metaheuristics employ random search, which
reduces the likelihood of converging to a random extremum. Metaheuristics are capable of solving
problems of discrete optimization (e.g., the traveling salesman problem, knapsack problem, assignment
problem, clustering) and continuous optimization (finding the point at which a function reaches an
extremum).</p>
      <p>Existing metaheuristics have one or more of the following drawbacks:
 failure to consider the impact of iteration number on the solution search process [14-15];
 the method's description is oriented towards solving only specific problems or is an abstract
method description [16-17];
 lack of guaranteed convergence of the method [18-19];
 inability to use non-binary potential solutions [20-21];
 insufficient accuracy of the method [22-23];
 inability to solve problems of constrained optimization [24-25];
 lack of automated procedure for determining parameter values [26-27].</p>
      <p>Therefore, the task arises to develop effective metaheuristic optimization methods. Among the most
popular are metaheuristics based on monkey behavior [28].</p>
    </sec>
    <sec id="sec-4">
      <title>3. Monkey search with dynamic parameters</title>
      <p>The "monkey search" was proposed by Mucherino [28] and is based on the behavior of a monkey
that climbs a tree in search of food, while remembering where it found good food in the past. Figure 1
shows a binary decision tree, with the path to the best node highlighted in bold. In this algorithm, the
monkey randomly climbs the tree and discovers new left and right nodes. Node discovery corresponds
to generating new solutions based on the current or current and best solution using perturbation. The
monkey stops when the current best node (best solution) is found or when the maximum tree height is
reached. Upon reaching either of these stopping conditions, the monkey descends back to the root node
of the tree.</p>
      <p>Then the monkey climbs up the tree again, choosing between previously discovered left and right
nodes, with a higher probability of selecting the best nodes. A new binary tree is created at each
iteration. When the number of nodes at the maximum tree level reaches a specified value, the
construction of the current tree is completed. This algorithm uses memory that stores the best solutions
obtained from the first trees. The first trees have randomly generated solutions as their roots, and
subsequent trees have roots of solutions from memory, randomly selected. After filling all memory with
the best solutions, if a new solution is better than one or more solutions in memory, then the new
solution replaces the worst solution in memory. If the new solution is too close to a solution in memory,
the new solution is ignored. The monkey search stops when the maximum number of built trees is
reached. In contrast to the original method, this method uses dynamic mean square deviation to generate
the position vector.</p>
      <p>3.1.</p>
    </sec>
    <sec id="sec-5">
      <title>Algorithm for optimizing numerical functions</title>
      <p>Initialization.
1.1. Specifying the minimum distance between vertex positions (solutions) in memory  , the
parameter  that controls the step size for generating a new solution, subject to the condition
that,   0 , 0    1.
1.2. Specifying the maximum number of trees N , maximum number of levels for each tree
H , maximum number of vertices for each tree H at a given level N H , memory size L , length
of the vertex position vector M , minimum and maximum values for the solution x mjin , x mjax ,
j 1, M .
1.3. Specifying the cost function (objective function) F(x)  min , where x is the vector
x
position of the tree vertex.
1.4. Creating the optimal solution randomly as a real vector</p>
      <p>
        x*  (x1*,..., xM* ) , x*j  x mjin  (x mjax  x mjin )U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) ,
where U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) - is the function returns a standard uniformly distributed random number.
(
        <xref ref-type="bibr" rid="ref1">1</xref>
        )
2.
3.
      </p>
      <p>1.5. Memory PM   .</p>
      <p>Tree number n  1 .</p>
      <p>Creation of the n -th tree.
3.1. Set of explored node positions Vn   .
3.2.</p>
      <p>Set of edges An   .
3.3. Set of node positions H at the level VnH   .
3.4. Exploring the root of the tree.</p>
      <p>3.4.1. If PM  L , then - randomly create a root position, then the root position is randomly
created.</p>
      <p>
        xroot  (x1root ,..., xMroot ) , xrjoot  x mjin  (x mjax  x mjin )U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) ,
3.4.2. If PM  L , then from memory, PM a vertex with a number is randomly selected
v  round (1 (L 1)U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        )) , which becomes a root xroot , where round () – is a function
rounding a number to the nearest integer.
3.4.3. Add the root position to the set of explored node positions
      </p>
      <p>
        {xroot }. (
        <xref ref-type="bibr" rid="ref3">3</xref>
        )
3.5.
      </p>
      <p>Vn  Vn
Set the position of the current tree vertex</p>
      <p>xcur  xroot .
3.6. Ascending to explored tree vertices.</p>
      <p>
        3.6.1. Tree level number m  1.
(
        <xref ref-type="bibr" rid="ref2">2</xref>
        )
(
        <xref ref-type="bibr" rid="ref4">4</xref>
        )
(
        <xref ref-type="bibr" rid="ref5">5</xref>
        )
(
        <xref ref-type="bibr" rid="ref6">6</xref>
        )
3.6.2. If xleft Vn : (xcur , xleft )  An and xright Vn : (xcur , xright )  An , then go to step 3.7.
3.6.3.
3.6.4.
      </p>
      <p>Calculate the probability of ascending to the left vertex</p>
      <p>1 / F (xleft )
p </p>
      <p>1 / F (xleft )  1 / F (xright ) .</p>
      <p>Select the position of the current vertex</p>
      <p>
        xleft ,
  U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) , xcur  
xright
p  
      </p>
      <p>.
p  
3.6.5. If m  H , then m  m  1, go to step 3.6.2, otherwise 3.5.
3.7. Ascending to unexplored tree vertices.</p>
      <p>
        3.7.1. Create the position of the left vertex xleft by perturbation (e.g., mutation).
3.7.1.1.  j (m)  1  Hm  (x mjax  x mjin ) , xljeft  xcjur  j (m)N (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) , j 1, M ,
where N (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) – is a function returning a standard normally distributed random number.
3.7.1.2.
      </p>
      <p>xleft  max{x mjin , xljeft } , xleft  min{x mjax , xljeft } , j 1, M .</p>
      <p>j j
3.7.2.</p>
      <p>Create the position of the right vertex xright by perturbation (e.g., mutation).
3.7.2.1.
3.7.2.2.</p>
      <p>
 j (m)  1 
</p>
      <p>
        Hm  (x mjax  x mjin ) , xrjight  xcjur  j (m)N (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) , j 1, M .
      </p>
      <p>xrjight  max{x mjin , xrjight } , xrjight  min{x mjax , xrjight } , j 1, M .
3.7.3. If F(xcur )  min{F(xleft ), F(xright )} , then go to step 3.7.1.</p>
      <p>V H  VnH</p>
      <p>n
3.7.8. If V H  N H , then go to step 3.5.</p>
      <p>n
3.7.5.
3.7.4.</p>
      <p>Vn  Vn
Add the edges to the set of edges</p>
      <p>{(xcur , xleft ),(xcur , xright )} .</p>
      <p>Add the vertex positions to the set of explored vertex positions</p>
      <p>{xleft , xright } .</p>
      <p>An  An
3.7.6. If m  H , then m  m  1, go to step 3.5.
3.7.7. Add the vertex position to the set of vertex positions H at the level</p>
      <p>{xleft , xright }.</p>
      <p>Determine the best vertex position of n -th tree
xbest  arg min F (x) .</p>
      <p>n xVnH</p>
      <p>Add the best vertex position of n -th tree to the memory.
5.1. If PM  0 , then PM  PM</p>
      <p>{xnbest } , go to step 6.
5.2. If PM  0  min x  xnbest   , then go to step 6.</p>
      <p>xPM
5.3. If PM  L , then PM  PM</p>
      <p>{xnbest } , go to step 6.
5.4. Determine the worst position in the memory.
5.5. If F(xworst )  F(xnbest ) , then PM  PM \ {xworst } , PM  PM
{xnbest } .</p>
      <p>If n  N , then n  n  1 , go to step 3, otherwise – stop.</p>
      <p>Identification of the best global position
x*  arg min F (x) .</p>
      <p>xPM</p>
      <sec id="sec-5-1">
        <title>The solution is x* .</title>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>4. Monkey Algorithm with Dynamic Parameters</title>
      <p>
        The Monkey Algorithm, proposed by Zhao and Tang [28], is based on the model of monkeys
climbing mountains. It consists of three processes: the climbing process, the observation-jump process,
and the somersault process. The climbing process is a step-by-step procedure of changing the positions
of the monkeys from their initial positions to new positions, which uses a pseudogradient stochastic
(
        <xref ref-type="bibr" rid="ref7">7</xref>
        )
(
        <xref ref-type="bibr" rid="ref8">8</xref>
        )
(
        <xref ref-type="bibr" rid="ref9">9</xref>
        )
(
        <xref ref-type="bibr" rid="ref10">10</xref>
        )
(
        <xref ref-type="bibr" rid="ref11">11</xref>
        )
approximation. After the climbing process, each monkey arrives at its vertex and enters the
observationjump process. It inspects its surroundings and determines if there are other positions higher than its
current position. If so, it jumps from the current position and then repeats the climbing process until it
reaches the mountain peak. After these processes, each monkey finds a local maximum mountain peak.
The goal of the somersault process is to make the monkeys find globally maximum mountain peaks in
new search areas. To achieve this, the monkeys perform a somersault into a new search area in the
direction of the center of the current positions of all the monkeys. In contrast to the original method,
this method uses dynamic step size to generate the position vector.
      </p>
      <p>Algorithm for optimizing numerical functions
4.1.</p>
    </sec>
    <sec id="sec-7">
      <title>Algorithm for optimizing numerical functions</title>
      <p>Initialization
1.1. Set the minimum and maximum step lengths amin , amax for generating the position vector
during the ascent process, and the minimum and maximum step lengths bmin ,bmax for generating
the position vector during the observation-jump process, meanwhile
amin  0, amax  0,bmin  0,bmax  0 .
1.2. Set the maximum number of iterations N , the maximum number of iterations for local
search N L , the population size K , the length of the monkey's position vector M , and the
minimum and maximum values for the position vector x mjin , x mjax , j 1, M .
1.3.</p>
      <p>Define the cost function (objective function):</p>
      <p>F(x)  min ,</p>
      <p>x
where x is the monkey's position vector.
1.4. Create the initial population P .</p>
      <p>1.4.1. Monkey number k  1 .
1.4.2. Generate a random position vector xk</p>
      <p>
        xk  (xk1,..., xkM ), xkj  x mjin  (x mjax  x mjin )U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ). (
        <xref ref-type="bibr" rid="ref13">13</xref>
        )
where U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) – is a function that returns a standard uniformly distributed random number.
1.4.3. If xk  P , then P  P
      </p>
      <p>{xk } , k  k  1 .</p>
      <p>1.4.4. If k  K , then go to step 1.4.2.
1.5. Determine the monkey with the best objective function value:</p>
      <p>k*  arg mk1i,nK F (xk ), x*  xk* .
2.
3.</p>
      <p>1.6.</p>
      <p>Number of iterations n  1 .</p>
      <p>Climbing process.
3.1. Monkey number k  1 .
3.2. m  1.
3.3. Create a position vector increment xk</p>
      <p>
        Set the initial step lengths a(
        <xref ref-type="bibr" rid="ref1">1</xref>
        )  amax , b(
        <xref ref-type="bibr" rid="ref1">1</xref>
        )  bmax .
      </p>
      <p>
        xk  (xk1,..., xkM ), xkj  round (1 2U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ))a(n),
where round () – is a function that rounds a number to the nearest integer.
3.4. Calculate the pseudo-gradient of the cost function
3.5.
      </p>
      <p>Create a position vector based on mutation
3.6. If j 1, M xmjin  y j  xmjax , then xk  y .
3.7. If m  N L , then m  m  1, go to step 3.3.
3.8. If k  K , then k  k  1 , go to step 3.2.</p>
      <p>Observation-jump process.
4.1. Monkey number k  1 .
4.2. Create a position vector y based on mutation</p>
      <p>
        y  ( y1,..., yM ), y j  xkj  (1  2U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ))b(n).
4.4. If k  K , then k  k  1 , go to step 4.2.
      </p>
      <p>Climbing process.
5.1. Monkey number k  1 .
5.2. m  1.
5.3. Create a position vector increment xk
5.4.</p>
      <p>
        Calculate the pseudo-gradient of the cost function
xk  (xk1,..., xkM ), xkj  round (1 2U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ))a(n).
      </p>
      <p>2xkj</p>
      <p>
        y  ( y1,..., yM ), y j  xkj  (1  2U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ))( j  xkj ).
      </p>
      <p>4.3. If  F ( y)  F (xk )  j 1, M x mjin  y j  x mjax  , then xk  y , otherwise go to step 4.2.
then n  n  1 , a(n)  amin  (amax  amin ) 1  n  , b(n)  bmin  (bmax  bmin ) 1  n  , go to step 3.</p>
      <p> N   N </p>
      <sec id="sec-7-1">
        <title>The result is x* .</title>
      </sec>
    </sec>
    <sec id="sec-8">
      <title>5. Optimization of Spider Monkey with Dynamic Parameters</title>
      <p>Spider Monkey Optimization (SMO) was proposed by Bansal, Sharma, Jadon, and Clerc [28] and is
based on the behavior of spider monkeys, which is based on the fission-fusion social structure (FFSS).</p>
      <p>
        The key features of FFSS are: An example of numbered list is as following.
(
        <xref ref-type="bibr" rid="ref18">18</xref>
        )
(
        <xref ref-type="bibr" rid="ref19">19</xref>
        )
(
        <xref ref-type="bibr" rid="ref20">20</xref>
        )
(
        <xref ref-type="bibr" rid="ref21">21</xref>
        )
(
        <xref ref-type="bibr" rid="ref22">22</xref>
        )
(
        <xref ref-type="bibr" rid="ref23">23</xref>
        )
(
        <xref ref-type="bibr" rid="ref24">24</xref>
        )
1. Animals based on FFSS are social and live in groups of 40-50 individuals. The FFSS swarm
can reduce competition for food among group members by dividing them into subgroups for food
search.
2. The female (global leader) usually leads the group and is responsible for finding food sources.
If she fails to obtain enough food for the group, she divides the group into smaller subgroups (ranging
in size from 3 to 8 members) who forage independently.
3. Subgroups should also be led by a female (local leader) who makes decisions about planning
an efficient feeding route for each day.
4. Members of these subgroups communicate within and outside the subgroup depending on the
availability of food and to maintain territorial boundaries.
      </p>
      <p>In the developed strategy, the behavior of animals living according to the FFSS principle (such as
spider monkeys) is divided into four stages. In the first stage, the group begins to search for food and
evaluates the distance to it. In the second stage, based on the distance to the food, group members update
their positions and reevaluate the distance to food sources. In the third stage, the local leader updates
her best position in the group, and if the position is not updated a certain number of times, all members
of this group begin to search for food in different directions. In the fourth stage, the global leader updates
her best position, and if it is not updated a certain number of times, she divides the group into smaller
subgroups. All four stages are performed continuously until the desired result is achieved. FFSS follows
the properties of self-organization and division of labor to achieve intelligent swarm behavior of
animals. However, the proposed algorithm differs from the natural behavior of spider monkeys. In this
algorithm, the leader's position (local or global) is not constant but depends on the leader's ability to
find food. In addition, the algorithm does not model the different communication tactics of spider
monkeys. This algorithm consists of six phases: Local Leader Phase, Global Leader Phase, Local
Leader Learning Phase, Global Leader Learning Phase, Local Leader Decision-making Phase, and
Global Leader Decision-making Phase. Unlike the original method, this method uses the dynamic
probability of retaining a solution and the dynamic probability of a random solution.
5.1.</p>
    </sec>
    <sec id="sec-9">
      <title>Algorithm for optimizing numerical functions</title>
      <p>Initialization.
1.1. Setting the minimum and maximum probabilities pmin , pmax .
1.2. Setting the maximum number of iterations N , the maximum number of groups Gmax , the
maximum number of iterations without updating the position of the local leader N LL (usually
N LL  M  K ), the maximum number of iterations without updating the position of the global
leader N G (usually</p>
      <p>NG [K / 2, 2K] ), the population size K ((for integer division of the
population into groups we assume K  60 ), the length of the monkey position vector M , and
the minimum and maximum values for the position vector x mjin , x mjax , j 1, M .
1.3.</p>
      <p>Setting the cost function (objective function) F(x)  min ,
x
where x – is the monkey position vector.
1.4. Number of groups G  1.
1.5. Creation of one group.</p>
      <p>1.5.1. Monkey number in the group. k  1 .
1.5.2. Random creation of a position vector xgk</p>
      <p>
        x1k  (x1k1,..., x1kM ) , x1kj  x mjin  (x mjax  x mjin )U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) ,
where U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) – is a function returning a standard uniformly distributed random number.
1.5.3. If x1k  P1 , then P1  P1
      </p>
      <p>{x1k } , k  k  1 .</p>
      <p>1.5.4. If k  P1 , then go to step 1.5.2.
1.6.</p>
      <p>Determine the local leader in the group
k*  arg min F (x1k ), x1*  x1k* .</p>
      <p>
        k1, P1
(
        <xref ref-type="bibr" rid="ref25">25</xref>
        )
(
        <xref ref-type="bibr" rid="ref26">26</xref>
        )
1.7.
      </p>
      <p>Determine the global leader</p>
      <p>x*  x1* .
1.8. Number of iterations without updating the position of the local leader</p>
      <p>
        m1  0.
1.9. Number of iterations without updating the position of the global leader
m  0.
1.10. Probability of preserving the position ps (
        <xref ref-type="bibr" rid="ref1">1</xref>
        )  pmin .
1.11. Probability of a random position pr (
        <xref ref-type="bibr" rid="ref1">1</xref>
        )  pmax .
      </p>
      <p>Iteration number n  1 .</p>
      <p>Local leader phase.
3.1. Group number g  1 .
3.2. Monkey number в g -group k  1 .
3.3. Component number j  1 .
3.4. Randomly select the number of the second monkey</p>
      <p>
        s  round 1   Pg 1U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ),
where round () – is a function that rounds a number to the nearest integer.
3.5. If s  k , then go to step 3.4.
3.6. Save the position vector or create a position vector based on the crossover (crossing the
position vector of the monkey with the position vectors of the local leader and the other monkey)
  U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ) ,
xgkj ,   ps (n)
xgkj  
xgkj  U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        )(x*gj  xgkj )  (1  2U (
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ))(xgsj  xgkj ),   ps (n)
.
      </p>
      <p>If j  M , then j  j 1 , go to step 3.4.</p>
      <p>If k  Pg , then k  k  1 , go to step 3.3.
3.9. If g  G , then g  g  1, go to step 3.2.</p>
      <p>Modify the position of group members.
4.1. Group number g  1 .
4.2. Monkey number в g -group k  1 .</p>
      <p>If F (xgk )  F (xgk ) , then xgk  xgk .</p>
      <p>If k  Pg , then k  k  1 , go to step 4.3.
4.5. If g  G , then g  g  1, go to step 4.2.</p>
      <p>Calculate probabilities for group members.
5.1. Group number g  1 .
5.2. Monkey number в g -group k  1
5.3.</p>
      <p>If k  Pg , then k  k  1 , go to step 5.3.
5.4. If g  G , then g  g  1, go to step 5.2.</p>
      <p>Global leader phase.
6.1. Group number g  1 .
6.2. c  1 .
6.3.
6.4.</p>
      <sec id="sec-9-1">
        <title>If c  Pg , then go to step 6.13.</title>
        <p>Monkey number в g -group k  1 .
6.5.
6.6.
6.7.</p>
        <p>
          If U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          )  pgk , then go to step 6.11.
c  c  1.
        </p>
        <p>Randomly select the component number j  1
6.8.</p>
        <p>
          Randomly select the number of the second monkey
j  round 1 M 1U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          ).
        </p>
        <p>
          s  round 1   Pg 1U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          ).
6.9. If s  k , then go to step 6.8.
6.10. Create a position vector based on the crossover
6.11. If k  Pg , then k  k  1 , go to step 6.5.
6.12. Modify the position of group members
xgkj  xgkj  U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          )(x*gj  xgkj )   (n)(1  2U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          ))(xgsj  xgkj ).
        </p>
        <p>xgk  xgk , k 1, Pg ,</p>
        <p>g 1,G.
6.13. If g  G , then g  g  1, go to step 6.2.</p>
        <p>Local leader learning phase.
7.1. Group number g  1 .</p>
        <p>7.2. Determine the best monkey in the g -group based on the objective function</p>
        <p>k*  arg min F (xgk ).</p>
        <p>k1, Pg</p>
        <p>Determine the local leader in the g -group.</p>
        <p>If F(xgk* )  F(x*g ) , then x*g  xgk* , mg  mg  1 .
7.4. If g  G , then g  g  1, go to step 7.2.</p>
        <p>Global leader training phase.
8.1. Determine the best local leader
g*  arg min F(x*g ).</p>
        <p>g1,G
8.2. Determine the global leader.</p>
        <p>If F(xg* )  F(x*) , then x*  xg* , otherwise m  m  1.</p>
        <p>Local leader decision-making phase.
9.1. Group number g  1 .
9.2.
9.3.</p>
        <p>If mg  N LL , then go to step 9.9.
9.4. Monkey number в g -group k  1 .
9.5. Component number j  1 .
9.6. Create a position vector randomly or based on the crossover (crossing the position vector
of the monkey with the position vectors of the global and local leaders)</p>
        <p>
            U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          ),
x mjin  (x mjax  x mjin )U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          ),   pr (n)
xgkj  
xgkj  U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          )(x*j  xgkj )  U (
          <xref ref-type="bibr" rid="ref1">0,1</xref>
          )(xgkj  x*gj ),   pr (n)
.
9.7.
9.8.
        </p>
        <p>If j  M , then j  j 1 , go to step 9.6.</p>
        <p>If k  Pg , then k  k  1 , go to step 9.5.</p>
        <p>9.9. If g  G , then g  g  1, go to step 9.2.
10. Global leader decision-making phase.</p>
        <p>10.1. If m  N G , then go to step 11.
(33)
(34)
(35)
(36)
(37)
(38)
(39)
P </p>
        <p>G
g1</p>
        <p>P .</p>
        <p>g
mg  0, g 1,G.
10.2. Number of iterations without updating the position of the global leader m  0 .
10.3. Fuse the group into the population
10.4. If G  Gmax , then G  G  1, fission the population P into G groups, go to step 10.6.
10.5. If G  Gmax , then G  1.
10.6. Determine local leaders in groups
x*g  arg min F(xgk ), g 1,G.</p>
        <p>k1, Pg
10.7. Number of iterations without updating the positions of local leaders
11. If n  N , then n  n  1 ,</p>
        <p>go to step 3.</p>
        <p>The result is x* .</p>
        <p>pr (n)  pmin  ( pmax  pmin )1 Nn , pr (n)  pmin  ( pmax  pmin ) Nn ,</p>
      </sec>
    </sec>
    <sec id="sec-10">
      <title>6. Numerical study of the proposed methods</title>
      <p>The numerical study was conducted on the Ackley function</p>
      <p>
         1 M   1 M 
f (x)  a exp b  x 2j   exp M j1 cos(cx j )   a  exp(
        <xref ref-type="bibr" rid="ref1">1</xref>
        ),
      </p>
      <p> M j1  
where a  20, b  0.2, c  2 , x mjin  32.768, x mjax  32.768 , M  30 .
distance between node positions in memory  </p>
      <p>In the study, the population size is K  60 the maximum number of iterations or trees N  100 (for
monkey search and monkey algorithm), or (for spider monkey optimization), were used minimum
|| xmax  xmin ||</p>
      <p>, a parameter controlling the step size for
8
generating a new solution   0.1 , the maximum number of levels for each tree H  100 , the maximum
number of vertices on H level N H  100 , memory size L  10 , minimum and maximum step lengths
amin  0.1, amax  0.001 for generating the position vector during the ascent process, minimum and
maximum step lengths bmin  1,bmax  10 for generating the position vector during the observation-jump
process, the maximum number of local search iterations N L  1000 , minimum and maximum
probabilities pmin  0.1, pmax  0.9 , the maximum number of groups Gmax  6 , the max number of
iterations without updating the position of the local leader N LL  1800 , the maximum number of
iterations without updating the position of the global leader N G  60 . The results of comparing the
proposed methods with classical methods are presented in Table 1.
(44)</p>
      <p>An example of a real-world applied problem is neural network training. A multi-layer perceptron
with five input neurons, one output neuron, one hidden layer, and 30 weight coefficients was selected
as the neural network, performing function approximation.</p>
    </sec>
    <sec id="sec-11">
      <title>7. Discussion</title>
      <p>The selected parameter values of the proposed parametric identification methods ensure a high
probability of mutation and random solution generation in the initial iterations and a low probability of
mutation and random solution generation in the final iterations.</p>
      <p>Classical methods based on the behavior of monkeys do not take into account the iteration number
in the mutation operator and the random solution generation operator, which reduces the accuracy of
the solution search (Table 1). The proposed methods allow for the elimination of these shortcomings.</p>
      <p>One limitation of the study is that the proposed methods used a population size of 60.</p>
    </sec>
    <sec id="sec-12">
      <title>8. Conclusions</title>
      <p>In the article, the problem of insufficient efficiency of parameter identification methods for artificial
neural network models used in intelligent computer systems is considered. To improve the efficiency
of parameter identification methods, metaheuristic methods based on the behavior of monkeys with
dynamic parameters were proposed, which improve upon classical methods (monkey search, monkey
algorithm, spider monkey optimization). The proposed methods of parameter identification, due to
global search at initial iterations and local search at final iterations, allow to increase the accuracy of
search and does not require the transformation of the target function. The proposed metaheuristics can
expand the scope of application of parameter identification methods based on monkey behavior and
contribute to the increase of efficiency of intelligent computer systems. The prospects of further
research include the investigation of the proposed methods for a wide range of artificial intelligence
tasks.</p>
    </sec>
    <sec id="sec-13">
      <title>9. References</title>
    </sec>
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