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Collocation method with flood-based metaheuristic optimizer for optimal control ...
            Advantages of the Collocation Method:                    applications such as the multi-strain
                                                                     COVID-19 model.
                 1- Efficient Transformation of OCP to NLP:
                    The collocation method turns the OCP          Thus, the hybrid strategy combines the best
                    with infinite dimensions into an NLP with  aspects of both approaches and creates a strong
                    finite dimensions. This makes it easier to  and valuable framework for solving OCPs accu-
                    solve computationally.                    rately and reliably.
                 2- Accuracy and Stability: Laguerre polyno-      Here, we organize the rest of the paper:
                    mials and their derivative operational ma-  First, definitions and notes are presented, fol-
                    trices are used in the collocation method  lowed by developing an optimal control strategy
                    to keep the numbers stable while getting  for a multi-strain COVID-19 model in Section 2.
                    good state and control variable estimates.  Section 3 outlines two methods for addressing this
                 3- Simplicity  and   Applicability:   The    issue. The results of computer experiments are
                    method’s straightforward implementation   discussed in Section 4. Finally, Section 5 summa-
                    makes it suitable for handling complex    rizes alternative research avenues in this field.
                    dynamical systems with nonlinear con-
                    straints.                                 2. Mathematical model for the
                                                                 multi-strain co-infection
            Advantages of the Flood-Based Meta-
            heuristic Optimizer (FBMO):                       In this section, we develop a compartmental epi-
                                                              demic model to investigate a multi-strain COVID-
                 1- Global Optimization: FBMO is an algo-
                                                              19 scenario on disease propagation dynamics and
                    rithm based on nature that finds near-    control measures. The OCP for the multi-strain
                    global optima in big, complicated opti-   COVID-19 model is shown mathematically using
                    mization problems. It does this by get-   the parameters and variables depicted in Tables 2
                    ting around the problems that local search  and 3.
                    methods have.
                                                                  Then, the multi-strain epidemic model can be
                 2- Computational Efficiency: The optimizer   mathematically described as a nonlinear system
                    uses tools like erosion coefficients and  of differential equations:
                    Gaussian random distributions to find the
                    best balance between exploration and ex-
                                                                  dS                            βSI c
                    ploitation. This lets it quickly find high-       =Λ − ψS − µS − βSI v −          ,   (1)
                                                                   dt                         1 + αI c
                    quality solutions.
                 3- Robustness for Complex Systems: The           dV  = − βI v V − µV + ψS,               (2)
                    FBMO is excellent at dealing with non-         dt
                    linear constraints and big problems, as       dI c
                                                                      = − (µ + c c + ρw c + (1 − ρ)w c )I c
                    shown by its performance in benchmark          dt
                    studies and engineering applications.                   βSI c
                                                                        +         ,                       (3)
                                                                          1 + αI c
            Improvements Achieved by the Hybrid
                                                                  dI v
            Strategy:                                                 =βI v V + βSI v + (1 − ρ)w c I c
                                                                  dt
                 1- Enhanced Computational Efficiency: The              − (µ + c v + wv)I v ,             (4)
                    hybrid strategy cuts computation time by      dR
                    a large amount while keeping the quality       dt  = − µR + w v I v + ρw c I c ,      (5)
                    of the solution. It does this by combining
                    the structured approach of the colloca-
                    tion method with the global optimization  based on the starting circumstances, where the
                    power of FBMO.                            values of S(0), E(0), I(0), V (0), and R(0) are not
                                                              negative. In addition, vaccines are effectual on
                 2- Improved Solution Quality: The hybrid     the common strain but ineffectual on the ampli-
                    method makes sure that the estimates of   fied strain, which is important for controlling the
                    the state and control variables are accu-  propagation of multi-strain disease. We present
                    rate and reliable, and it solves the result-  the flowchart of the model (1)-(5) as in Figure 1.
                    ing NLP quickly to find the best solutions.   In our study, we introduce three key con-
                                                              trol strategies. Let u 1 (t) symbolize the adjust-
                 3- Scalability: The hybrid strategy is scal-  ments to vaccination tactics. We utilize revised
                    able and adaptable to various complex     disease transmission rates to illustrate the im-
                    OCPs, making it suitable for real-world   pacts of isolation strategies and media coverage,
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