卷 79, 编号 12 (2018)

We consider the problem of optimal parametric control for a single oscillator or an ensemble of oscillators due to a change in one of the coefficients of the system of equations characterizing them. We obtain solutions for the problem of finding the maximal change in the energy of oscillations for a given time.

We study a model containing coupled subsystems (MCCS) defined by a system of ordinary differential equations, where subsystems are systems of autonomous ordinary differential equations. The model splits into unrelated systems when the numerical parameter that characterizes couplings is ε = 0, and the couplings are given by time-periodic functions. We solve the natural stabilization problem which consists in finding relationships that simultaneously guarantee the existence and asymptotic stability of MCCS oscillations. We generalize results previously obtained for the case of two coupled subsystems each of which is defined on its own plane.

We consider a single-line RQ-system with collisions with Poisson arrival process; the servicing time and time delay of calls on the orbit have exponential distribution laws. Each call in orbit has the “impatience” property, that is, it can leave the system after a random time. The problem is to find the stationary distribution of the number of calls on the orbit in the system under consideration. We construct Kolmogorov equations for the distribution of state probabilities in the system in steady-state mode. To find the final probabilities, we propose a numerical algorithm and an asymptotic analysis method under the assumption of a long delay and high patience of calls in orbit. We show that the number of calls in orbit is asymptotically normal. Based on this numerical analysis, we determine the range of applicability of our asymptotic results.

We consider the problem of identifying unknown nonstationary piecewise linear parameters for a linear regression model. A new algorithm is proposed that allows, in the case of a number of assumptions on the elements of the regressor, to provide an estimate of unknown non-stationary parameters. We analyze in detail the case with two unknown parameters, which makes it possible to understand the main idea of the proposed approach. We also consider a generalization to the case of an arbitrary number of parameters. We give an example of computer simulation that illustrates the efficiency of the proposed approach.

Within the framework of the block approach, we propose a solution for a set of tasks for controlling a steam generator, i.e., a turbine unit under parametric uncertainty of the control object model, under the action of external uncontrolled disturbances and under incomplete measurements of the state vector. The feasibility of developed control algorithms has been confirmed by a simulation study in the Matlab–Simulink environment.

We propose an algorithm, linear in both running time and memory, that constructs a sequence of operations that transform any given directed graph with degree of any vertex at most two to any other given graph of the same type with minimal total cost. This sequence is called the shortest one. We allow four standard operations of re-gluing graphs with equal cost and two more additional operations of inserting and deleting a connected section of edges that also have equal cost. We prove that the algorithm finds a minimum with this restriction on the costs.

This paper defines the self-covariance property for the solutions of transferable utility cooperative games (TU-games) as a weakening of their covariance. Self-covariant solutions are positively homogenous and satisfy a “restricted” translation covariance so that feasible shifts are only the solution vectors themselves and their multipliers. A description of all non-empty, single-valued, efficient, anonymous, weakly and self-covariant solutions in the class of twoplayer TU-games is given. As demonstrated below, among them there exist just three solutions admitting consistent extensions in the Davis–Maschler sense. They are the equal share solution, the standard solution, and the constrained egalitarian solution for superadditive two-player TUgames. For the third solution mentioned, characterizations of some consistent extensions to the class of all TU-games are given.