Vol 80, No 6 (2019)

We describe certain classes of linear asynchronous multi-agent systems in discrete time for which the stability problem allows for a constructive solution. We also present a general analytic approach to constructing numerical characteristics similar to the generalized spectral radius in stability theory, which would provide an opportunity to analyze the stabilizability of controlled multi-agent systems. This work completes our survey “Consensus in Asynchronous Multi-Agent Systems,” whose first two parts have been published in [1, 2].

The time-delay systems are considered and the limiting behavior of their solutions is investigated. The case in which the solutions have the trivial equilibrium that may not be an invariant set of the system is studied. The notion of an asymptotic quiescent position for the trajectories of delayed systems is introduced. Its stability is analyzed by the method of Lyapunov functions using the Razumikhin approach. Sufficient conditions for the existence of an asymptotic quiescent position for one class of the systems of differential-difference equations are established. Some illustrative examples of nonlinear differential equations with delay that have an asymptotic quiescent position are given and the sufficient conditions are applied to them.

Two-stage stochastic programming problems with the probabilistic and quantile criteria in the general statement are considered. Sufficient conditions for the measurability of the loss function and also for the semicontinuity of the criterion functions are given. Sufficient conditions for the existence of optimal strategies are established. The equivalence of the a priori and a posteriori statements of the problems under study is proved. The application of the confidence method, which consists in the transition to a deterministic minimax problem, is described and justified. Sample approximations of the problems are constructed and also conditions under which the optimal strategies in the approximating problems converge to the optimal strategy in the original problem are presented. The results are illustrated by an example of the linear two-step problem. The two-stage problem with the probabilistic criterion is reduced to a mixed-integer problem.

A system of difference-differential equations for the expected incomes of open Markov queueing networks with different peculiarities is considered. The number of network states and also the number of equations in this system are both infinite. The incoming flows of requests are elementary and independent while their service times have exponential distributions. The incomes from transitions between different states of the network are deterministic functions that depend on its states; the incomes gained by the queuing server systems per unit time under the invariable states also depend on these states only. The system of the difference-differential equations is solved using the modified method of successive approximations combined with the series method. An example of a Markov G-network with signals and the group elimination of positive requests is studied. As demonstrated below, the expected incomes can be increasing and decreasing time-varying functions; can take positive and negative values.

We introduce the concept of sum codes with fixed values of the multiplicities of unidirectional and asymmetrical errors in data vectors. We show that such codes can be constructed on the basis of weighing one of the data vector's bits by a natural number w = 2 and then calculating the total weight of the data vector modulo the Berger code (M = 2[^log₂(m^+1)]). We establish the basic characteristics of the new class of sum codes. Compared with the Berger code, the proposed codes have the advantage of detecting symmetrical errors while maintaining the property of detecting any unidirectional and asymmetrical errors up to fixed multiplicities. Such codes can be effectively used in the construction of concurrent error-detection systems for combinational logic devices and, especially, in the construction of systems with the detection of all single faults in the controlled device.

We propose an approach for controlling the weighted average price of a manufacturers sales on commodity exchanges. This problem is highly relevant due to the need for the manufacturer to hedge their profits in case of a sharp drop in market prices. We consider applications of the proposed control to executing trading operations on real commodity exchanges in order to demonstrate its efficiency.

The control problem of an organizational system under external uncertainty is considered. The reasonability of using decentralized control depending on the volume of available information about uncertain factors is investigated. The qualitative structure of optimal strategies with centralized and decentralized control is studied.

It is noted, that information-technological reserve is a new type of information redundancy, the use of which in distributed automated informational control systems allows to increase the efficiency of their performance while processing the typical user requests. The task of optimal allocation of identical copies of information-technological reserve throughout the nodes of the distributed system is formulated in the form of a minisum problem of finding the p-median of a graph. The algorithm is proposed for solving this problem and the example of the solution is given. The brief analysis of the solution algorithm results is performed.

This paper deals with a generalization of the famous Bondareva-Shapley theorem [1, 9] on the core of TU cooperative games to the case of fuzzy blocking. The suggested approach is based on the concept of a balanced collection of fuzzy coalitions. Introduced by the author, this extension of the classical balanced collection of standard coalitions yields a natural analog of balancedness for the so-called fuzzy TU cooperative games. As established below, the general balancedness is a necessary and sufficient condition for the non-emptiness of the core of fuzzy TU cooperative games. The non-emptiness criterion of the core is further refined using the classical Helly's theorem on the intersection of convex sets. The S*-representation of a fuzzy game is studied, which simplifies the existence conditions for non-blocking imputations of this game in a series of cases.

This paper considers the issues associated with the practical problem of optimal life cycle of a lengthy heat supply network section. We present a mathematical model and basic algorithms yielding optimal maintenance graphs for one or two collocated lengthy heat supply network sections. The optimal repair times are calculated and the corresponding economic effect is estimated by an example of four collocated sections.