Some Problems of Analysis of Hybrid Automata

Skobelev, V. V.; Skobelev, V. G.

doi:10.1007/s10559-018-0053-9

Cited by 8 publications

(4 citation statements)

References 4 publications

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“…The method differs from the organization of direct transitions between the states themselves as is programmed in the discrete-event models. The form for the algorithmic implementation of the model in the computing environment is a hybrid machine [ 19 ]. We present such a transition machine in the AnyLogic environment as a graph with oriented arcs: the directions of the transformation of the right-hand side of the initial position by the order of activation of the nodes of the graph.…”

Section: Methodology For Building Hybrid Structures In Ecodynamicsmentioning

confidence: 99%

Methodology of the Construction of Computational Scenarios for Modeling Extreme States in Living Systems

Perevaryukha

2021

J. Comput. Syst. Sci. Int.

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We consider a methodology for organizing hybrid computing structures to simulate abrupt changes in controlled natural processes and analyzing phases of extreme environmental phenomena. Systems of differential equations with the dynamically redefinable right-hand side at special moments (events) are used. The truth conditions for transitions are obtained from computing other equations for additional characteristics of the state of a generation. Threshold states in process modeling are the result of the inclusion of trigger functions. Their values on the right-hand side are specifically different from the neutral value only in narrow ranges of the space of changing characteristics of a hybrid system and depend on the initial conditions. The restricted limits of functions and their domain of values rest on the core of the threshold effects for the simulated biosystem, which are observed under special conditions. The method allows us to implement actual qualitative changes in management scenarios as bifurcations of the appearance (reduction) of equilibrium states or the boundary crisis of a complex attractor consisting of intervals scattered in a limited area. Computational scenarios for different population processes are investigated. The collapse of fish stocks is described in the model by the examples of cod in the North Atlantic and sturgeon in the Caspian Sea. The rapid outbreak of their abundance is modeled according to observations on the pulsation of the population size of pests of relict evergreen forests. The threshold scenario of the outbreak of insects in the scenario ends spontaneously due to the local exhaustion of forest resources with a sharp transition to fluctuations of the pest, which are ordinary for the environment. The methodology of organizing the structure for the population model is summarized to predict a wide range of extreme processes related to rapid changes in controlled biological systems and the spread of unwanted biological invasions.

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Section: Methodology For Building Hybrid Structures In Ecodynamicsmentioning

confidence: 99%

Methodology of the Construction of Computational Scenarios for Modeling Extreme States in Living Systems

Perevaryukha

2021

J. Comput. Syst. Sci. Int.

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“…Graph vertices correspond to state-change modes, and edges correspond to transitions between alternative state-change modes (but not between states themselves) specified by the conditions of Boolean functions. A specific hybrid automaton can be a nested element for a higher-order aggregated automaton in the process hierarchy of a heterogeneous system [12].…”

Section: Formalization Of Hierarchical Continuous Time With Eventsmentioning

confidence: 99%

Modeling of a Crisis in the Biophysical Process by the Method of Predicative Hybrid Structures

Perevaryukha

2022

Tech. Phys.

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Crisis processes of biosystems often develop according to scenarios of rapid collapse, which cannot be predicted by statistical methods. This paper develops a method for constructing hybrid computational models using event-hierarchy representation for biophysical processes. System events calculated by the algorithm change the order of calculation of equations according to a given set of rules. The rules of physically conditioned redefinition of the right-hand sides of differential equations are used. The predicates employ the calculations of a group of accompanying characteristics, which are an integral part of the controlled biophysical dynamics. The model is investigated by presenting a computational scenario with a set of parameters, initial values, and an algorithm for making decisions about changing the impact for discrete time. Using computational experiments, a real outcome scenario for a situation that leads to the collapse of a biophysical system at a controlled level of exposure is described. The scenario sets the logic for making control decisions to change the level of external pressure on the natural environment. It is shown as a result of modeling that the transition of the process to an oscillatory mode leads to the choice of a risky control mode. It has been established that the dynamics of many real water populations has a point of threshold reduction in the efficiency of replenishment of stocks. The model scenario uses transformations of the phase portrait of iterations, which, in the presence of disconnected boundaries of the areas of attraction of alternative attractors and a strange chaotic repeller, lead to the uncertainty effects arising due to chaotic modes in a deterministic model. The properties of the described model scenario with a chaotic regime of dynamics are confirmed by the example of the catch of oceanic species of crustaceans.

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“…The hybrid automaton [7] is one of the most used modeling formalisms joined to this class of mixed approaches. Hybrid Automata (HA) have mainly been adopted for the analysis and verification of hybrid systems [8][9][10]. However, this modeling framework cannot be tailored in the case of control hybrid system synthesis.…”

Section: Introductionmentioning

confidence: 99%

MLD-MPC Approach for Three-Tank Hybrid Benchmark Problem

Yaakoubi¹,

Rezk²,

Al‐Dhaifallah³

et al. 2023

Computers, Materials &Amp; Continua

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The present paper aims at validating a Model Predictive Control (MPC), based on the Mixed Logical Dynamical (MLD) model, for Hybrid Dynamic Systems (HDSs) that explicitly involve continuous dynamics and discrete events. The proposed benchmark system is a three-tank process, which is a typical case study of HDSs. The MLD-MPC controller is applied to the level control of the considered tank system. The study is initially focused on the MLD approach that allows consideration of the interacting continuous dynamics with discrete events and includes the operating constraints. This feature of MLD modeling is very advantageous when an MPC controller synthesis for the HDSs is designed. Once the MLD model of the system is well-posed, then the MPC law synthesis can be developed based on the Mixed Integer Programming (MIP) optimization problem. For solving this MIP problem, a Branch and Bound (B&B) algorithm is proposed to determine the optimal control inputs. Then, a comparative study is carried out to illustrate the effectiveness of the proposed hybrid controller for the HDSs compared to the standard MPC approach. Performances results show that the MLD-MPC approach outperforms the standard MPC one that doesn't consider the hybrid aspect of the system. The paper also shows a behavioral test of the MLD-MPC controller against disturbances deemed as liquid leaks from the system. The results are very satisfactory and show that the tracking error is minimal less than 0.1% in nominal conditions and less than 0.6% in the presence of disturbances. Such results confirm the success of the MLD-MPC approach for the control of the HDSs.

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Some Problems of Analysis of Hybrid Automata

Cited by 8 publications

References 4 publications

Methodology of the Construction of Computational Scenarios for Modeling Extreme States in Living Systems

Methodology of the Construction of Computational Scenarios for Modeling Extreme States in Living Systems

Modeling of a Crisis in the Biophysical Process by the Method of Predicative Hybrid Structures

MLD-MPC Approach for Three-Tank Hybrid Benchmark Problem

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