We give an analytic proof of the existence of Shilnikov chaos in complex Ginzburg– Landau equation subject to a large third-order dispersion perturbation.

A parabolic partial differential equation u′_t (t, x) = Lu(t, x) is considered, where L is a linear second-order differential operator with time-independent coefficients, which may depend on x. We assume that the spatial coordinate x belongs to a finiteor infinite-dimensional real separable Hilbert space H.

Assuming the existence of a strongly continuous resolving semigroup for this equation, we construct a representation of this semigroup by a Feynman formula, i.e. we write it in the form of the limit of a multiple integral over H as the multiplicity of the integral tends to infinity. This representation gives a unique solution to the Cauchy problem in the uniform closure of the set of smooth cylindrical functions on H. Moreover, this solution depends continuously on the initial condition. In the case where the coefficient of the first-derivative term in L vanishes we prove that the strongly continuous resolving semigroup exists (this implies the existence of the unique solution to the Cauchy problem in the class mentioned above) and that the solution to the Cauchy problem depends continuously on the coefficients of the equation.

The article is published in the author’s wording.

We consider the mathematical model in which an operating processor serves the set of the stationary objects positioned in a one-dimensional working zone. The processor performs two voyages between the uttermost points of the zone: the forward or direct one, where certain objects are served, and the return one, where remaining objects are served. Servicing of the object cannot start earlier than its ready date. The individual penalty function is assigned to every object, the function depending on the servicing completion time. Minimized criteria of schedule quality are assumed to be total service duration and total penalty. We formulate and study optimization problems with one and two criteria. Proposed algorithms are based on dynamic programming and Pareto principle, the implementations of these algorithms are demonstrated on numerical examples. We show that the algorithm for the problem of processing time minimization is polynomial, and that the problem of total penalty minimization is NP-hard. Correspondingly, the bicriteria problem with the mentioned evaluation criteria is fundamentally intractable, computational complexity of the schedule structure algorithm is exponential. The model describes the fuel supply processes to the diesel-electrical dredgers which extract non-metallic building materials (sand, gravel) in large-scale areas of inland waterways. Similar models and optimization problems are important, for example, in applications like the control of satellite group refueling and regular civil aircraft refueling.

The article is published in the author’s wording.

A system of two logistic equations with delay coupled by delayed control is considered. It is shown that in the case of a sufficiently large delay control coefficient the problem of the dynamics of the initial systems is reduced to studying the non-local dynamics of special families of partial differential equations that do not contain small and large parameters. New interesting dynamic phenomena were discovered on the basis of the results of numerical analysis. Systems of three logistic delay equations with two types of ”diffusion” relation were considered. Special families of partial differential equations that do not contain small and large parameters were also constructed for each of these systems. The results of the study of the original equations dynamic properties are presented. It is shown that the difference in the dynamics of the considered systems of three equations may be of a fundamental nature.

Process mining is a relatively new field of computer science, which deals with process discovery and analysis based on event logs. In this paper we consider the problem of models and event logs conformance checking. Conformance checking is intensively studied in the frame of process mining research, but only models and event logs of the same granularity were considered in the literature. Here we present and justify the method of checking conformance between a high-level model (e.g. built by an expert) and a low-level log (generated by a system).

The article is published in the author’s wording.

The article is devoted to the mathematical modeling of neural activity. We propose new classes of singularly perturbed differential-difference equations with delay of Volterra type. With these systems, the models as a single neuron or neural networks are described. We study attractors of ring systems of unidirectionally coupled impulse neurons in the case where the number of links in the system increases indefinitely. In order to study periodic solutions of travelling wave type of this system, some special tricks are used which reduce the existence and stability problems for cycles to the investigation of auxiliary system with impulse actions. Using this approach, we establish that the number of stable self-excited waves simultaneously existing in the chain increases unboundedly as the number of links of the chain increases, that is, the well-known buffer phenomenon occurs.

In this paper the problem of existence and stability of continuous waves in a semiconductor laser model is studied. This model was proposed by Lang and Kobayashi and has the form of two differential equations with delay. The delay time is assumed to be large. We study the existence of continuous waves in the Lang-Kobayashi model. A special set I depending on all parameters of the problem is built. The condition of existence of continuous waves is that the ”‘main parts”’ of solutions must be located on the set I. Sufficient conditions of stability and instability of continuous waves are found for all sufficiently large values of delay. In the case of a zero linewidth enhancement factor the necessary and sufficient conditions of stability are found. Location of stability regions on the sets I is studied. It is proved that in the case of the zero linewidth enhancement factor the number of regions of stability on the set I is less than two. Necessary and sufficient conditions of existence of stability regions on the set I are found in this case.

We consider a differential-difference equation of second order of delay type, containing the delay of the function and its derivatives. Such equations occur in the modeling of electronic devices. The nature of the loss of the zero solution stability is studied. The possibility of stability loss related to the passing of two pairs of purely imaginary roots, that are in resonance 1:3, through an imaginary axis is shown. In this case bifurcating oscillatory solutions are studied. It is noted the existence of a chaotic attractor for which Lyapunov exponents and Lyapunov dimension are calculated. As an investigation techniques we use the theory of integral manifolds and normal forms method for nonlinear differential equations.