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Results of this paper extend the set of criteria which characterize the scheduling quality as well as the set of possible scheduling strategies. A new view on the minimum makespan criterion is presented in terms of the mean squared load of processing units. This leads in turn to the development of new scheduling algorithms. The interaction between processes of minimizing the new criteria and the maximum...
The paper deals with the problem of continuous-time (CT) identification of parameters in transfer functions for low-order linear systems, based on recorded discrete-time (DT) data. Algorithms for direct estimation of CT parameters are developed from rules for transformation of a CT transferfunction controlled via a zero-order sampling-and-hold unit into a DT representation.Two schemes are derived...
In this article, we study the global controllability properties of aone-dimensional semilinear heat equation with sublinear reaction term, governed in a bounded domain by internal lumped controls. We prove thatit is possible to exactly control any finite dimensional portion of its solution (when expanded along the sequence of the eigenfunctions of the associated Laplacian), provided that the truncated...
A new class of multi-dimensional discrete systems with varying structureis introduced. The notions of total solvability, p_t-boundedness, p_t-stability and asymptotic stability are defined. For studying properties of the solutions for the considered systems a curvilinear composition of mappings along discrete curves is used. Total solvability conditions similar to the Frobenius ones are obtained....
A reaching law approach to the design of discrete-time quasi-sliding mode control systems is considered. First the required position of the system representative point with reference to the sliding plane is specified, and then novel control strategies, which drive the system in such a way that the position actually changes according to the specification, are proposed. The strategies are linear and...
This paper focuses on single-input single-output nonlinear differential difference equation (DDE) systems with uncertain variables. For such systems, a general methodology is developed for the synthesis of robust nonlinear state feedback controllers that guarantee boundedness of the states and ensure that the ultimate discrepancy between the output and the external reference input in the closed-loop...
The purpose of this paper is to show for parabolic systems how one can achieve a final gradient in a subregion w of the system domain W. First, we give a definition and delineate some properties of this new concept, and then we introduce the concept of regionally gradient strategic actuators. The importance of the spatial structure and location of the actuators in achieving regional gradient controllability...
This paper deals with an optimal harvesting problem for a nonlinear age-dependent population dynamics. The existence and uniqueness of a positive solution for the model considered is demonstrated. The existence of an optimal harvesting effort and the convergence of a certain fractional step scheme are investigated. Necessary optimality conditions for some approximating problems are established.
Marchuk's model of an immune reaction is a system of differential equations with a time delay. The aim of this paper is to study the behaviour of solutions to Marchuk's model depending upon the delay of immune reaction and the history of an illness. We study Marchuk's model without delays, with aconstant delay and with an infinite delay. A continuous dependence on thedelay is considered. Bifurcation...
A cellular automaton model is presented in order to describe mutual interactions among the individuals of a population due to social decisions.The scheme is used for getting qualitative results, comparable to field experiments carried out on a population of ants which present an aggregative behavior. We also present a second description of a biological spatially structured population of N individuals...
A cell population model is constructed and analysed in the frameworkof general branching process theory. The model uses the idea that the DNA division cycle and the cell growth cycle are loosely coupled. The cell division is assumed to be unequal and the structure variables of the modelare size and growth, where the growth is regulated by supramitotic growth control. An explicit expression for the...
Individual-based simulations of a simple prey-predator system of Lotka-Volterra type were carried out on a tessellation of identical squares with discrete time steps. The particles representing individuals moved freely along (roughly) straight lines with constant (on the average) velocity, and changed their movement during a collision with another particle. Individuals were of two types: preys (with...
For an age-dependent model with a dominant age class an w-periodic regime of the population size is sought by means of impulsive perturbations. For both noncritical and critical cases of first order the problem is reduced to operator systems solvable by a convergent simple iteration method.
For a system of nonlinear difference equations that models the dynamics of exploited biological populations, a locally optimal periodic solutionis constructed. If this solution is unstable, a stabilizing feedback in the harvesting is introduced. The method is applied to an age-structured population model in fishery as well as to a host-parasitoid system for which the number of hosts and the number...
This paper proves global asymptotic convergence in a multitype epidemic model which encompasses both the S --> I and S --> I --> S epidemics. Systems are considered where the infection matrix may be reducible, and for which the system may be closed or can be open with a stable population size. New global asymptotic convergence results are obtained.
Two deterministic age-sex-structured population dynamics models are discussed taking into account random mating of sexes (without formation of permanent male-female couples), possible destruction of the fetus (abortion), and female's pregnancy. One of them deals with both random and directed diffusion in the whole space while in the other the population is assumed to be nondispersing. The population...
This paper studies the dynamics of a chemostat model with n populations competing for one nutrient which can be recycled due to decomposition of dead biomass. Several kinds of results about local and global stability of non-negative equilibria, uniform persistence and control of populations are obtained.
In a discrete Lotka-Volterra model, the set of points where a population remains unchanged over one generation is a hyperplane. Examining the relative position of these hyperplanes, we give sufficient conditions for a groupof species to drive another species to extinction. Further using these hyperplanes, we find necessary and sufficient conditions where every w-limit point of the model has at least...
The purpose of this paper is to report some original results on regional boundary observation and boundary strategic sensors. Characterization of such sensors is related to their spatial structure and location, and aims at achieving regional boundary observability for parabolic systems. An application to a two-dimensional diffusion process and various illustrative examples are demonstrated.
Two ways of speed stabilization of the D.C. motor are considered. One way consists in the use of additional kinetic energy accumulated in a wheel with a large moment of inertia J. The other consists in the use of additional information supplied by a feedback loop with gain K. In both the cases the motor is under the influence of the same white Gaussion noise. These two ways of stabilization are compared...
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