This article is aimed at solving an urgent problem for modern transport science – development of tools to support the modeling of railway transport objects. Since railway transport belongs to the category of so-call...
This article is aimed at solving an urgent problem for modern transport science – development of tools to support the modeling of railway transport objects. Since railway transport belongs to the category of so-called “complex systems”, the analytical approach is of little use for carrying out system analysis using methods of mathematical modeling, and it is necessary to use the simulation modeling methods. During the analysis of the subject area and the known approaches used for simulation modeling of complex technical systems, it was found that, firstly, the most convenient in this case is the method of agent-based modeling; secondly, AnyLogic that has a well-developed railway library is the most suitable as a modeling environment. The railway marshalling yard is considered as an object of modeling. The main technological processes are built in the form of blocks of the AnyLogic railway library. The simulation process of the model is visualized and presented in 3D. The offered method is suitable for describing a wide range of systems for freight and passenger transport that is expected to be implemented in the future.
The present paper is concerned with a nonlinear partial differential controlsystem subject to a state-dependent and nonconvex control constraint. This system models the dynamics of populations in the vegetation–prey...
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The Baikal Natural Territory includes Lake Baikal, its water protection zone, the basin within the territory of the Russian Federation, adjacent specially protected natural areas, and also the territory adjacent to th...
The Baikal Natural Territory includes Lake Baikal, its water protection zone, the basin within the territory of the Russian Federation, adjacent specially protected natural areas, and also the territory adjacent to the lake up to 200 kilometers wide to the west and northwest of it. The development of decisions to solve environmental problems of Baikal Natural Territory should be based on a comprehensive analysis of the monitoring data. The monitoring data and analysis methods are distributed among participants (organizations and departments). But data and analysis methods exchange is very low. An approach is proposed for the introduction of digitalization in the environmental monitoring of the Baikal natural territory, based on the integrated implementation of cyber-physical systems, the digital method of data transmission, as well as the use of digital ecosystems and platforms using the service-oriented paradigm, OGC standards, end-to-end and WEB technologies, cloud and distributed computing, large amounts of spatio-temporal data. Based on service-oriented paradigm digital resources and processing services implementing REST or WPS standard should be created by the monitoring participants. Requirements for digital resources have been defined. Infrastructure components have been developed to simplify development of digital resources, processing services and to organize interaction among participants.
A nonlocal chiral quark model is consistently extended beyond mean field using a strict 1/Nc expansion scheme. The parameters of the nonlocal model are refitted so that the physical values of the pion mass and the wea...
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A nonlocal chiral quark model is consistently extended beyond mean field using a strict 1/Nc expansion scheme. The parameters of the nonlocal model are refitted so that the physical values of the pion mass and the weak pion decay constant are obtained. The size of the 1/Nc correction to the quark condensate is carefully studied and compared with the usual local Nambu–Jona-Lasinio model. It is found that even the sign of the corrections can be different. This can be attributed to the mesonic cutoff of the local model. The model is also applied to finite temperature. We find that the 1/Nc corrections dominate the melting of the chiral condensate at low temperatures, T≲100 MeV, in agreement with chiral perturbation theory. On the other hand, the relative importance of the 1/Nc corrections in the crossover regime depends on the parameter T0 of the Polyakov-loop potential. For T0=270 MeV, corresponding to a fit of lattice data for pure gluodynamics, the correction terms are large and lead to a lowering of the chiral phase-transition temperature in comparison with the mean-field result. Near the phase transition the 1/Nc expansion breaks down and a nonperturbative scheme is needed to include mesonic correlations in that regime. Lowering T0 leads to a more rapid crossover even at the mean-field level and the unstable region for the 1/Nc corrections shrinks. For T0≲220 MeV the temperatures of deconfinement and chiral restoration are practically synchronized.
The paper presents a novel approach to solving a problem generally arising in studying dynamical systems, namely the problem of a system’s properties preservation under some transformation. Combining algebra, logic a...
The paper presents a novel approach to solving a problem generally arising in studying dynamical systems, namely the problem of a system’s properties preservation under some transformation. Combining algebra, logic and dynamics, the method of logical-algebraic equations (LAE-method) is developed, serving to synthesize criteria for preservation properties of systems connected by special type of morphisms. The LAE-method is applicable to various systems, but we focus on the case of discrete-event systems (DES), which are the systems that evolve in time due to the occurrence of some event sequences. We consider the issues of the LAE-method application to the reduction of supervisor for DES, the problems of DES basic properties, such as observability and controllability, preservation when sensor readings provide information about system’s state and it is available to a supervisor. Decentralized supervisory control is also addressed, in particular, the question whether local supervisors properties are inherited in a global supervisor.
In spite of intensive study since 1980s, there are still a lot of open problems in the supervisory controltheory of discrete-event systems (DES), especially partially observed and decentralized ones, due to complexit...
In spite of intensive study since 1980s, there are still a lot of open problems in the supervisory controltheory of discrete-event systems (DES), especially partially observed and decentralized ones, due to complexity issues of supervisor’s construction and verification algorithms. An important problem is the decentralized supervisory control, implemented by a set of automata each observing its own part of the system behavior. Preservation of co-observability of specification languages for DES under state space reduction, which is applied to reduce SCT algorithms computational complexity, is studied. One popular automata abstraction is considered and conditions for its applicability are obtained using the method of logical-algebraic equations.
The exciton spin dynamics are investigated both experimentally and theoretically in two-monolayer-thick GaAs/AlAs quantum wells with an indirect band gap and a type-II band alignment. The magnetic field induced circul...
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The exciton spin dynamics are investigated both experimentally and theoretically in two-monolayer-thick GaAs/AlAs quantum wells with an indirect band gap and a type-II band alignment. The magnetic field induced circular polarization of photoluminescence Pc is studied as function of the magnetic field strength and direction as well as sample temperature. The observed nonmonotonic behavior of these functions is provided by the interplay of bright and dark exciton states contributing to the emission. To interpret the experiment, we have developed a kinetic master equation model which accounts for the dynamics of the spin states in this exciton quartet, radiative and nonradiative recombination processes, and redistribution of excitons between these states as result of spin relaxation. The model offers quantitative agreement with experiment and allows us to evaluate, for the studied structure, the heavy-hole g factor, ghh=+3.5, and the spin relaxation times of electron, τse=33μs, and hole, τsh=3μs, bound in the exciton.
The paper describes a method and tools for prototyping components of intelligent systems. These means are the parts of the PESoT technology based on generative and visual programming as well as the model transformatio...
The paper describes a method and tools for prototyping components of intelligent systems. These means are the parts of the PESoT technology based on generative and visual programming as well as the model transformations. The proposed method redefines the main stages and models of the standardized model-driven approach, in particular, Model Driven Architecture in the context of developing knowledge bases and expert systems that use the logical rules formalism. The description of the method is presented. Proposed tools include languages and software. Specifically, the Rule Visual Modeling Language and Personal Knowledge Base Designer are used for knowledge bases engineering including modeling and codification; the Transformation Model Representation Language and Knowledge Base Development system support model transformations and the rapid creation of computation-independent models. Described tools were applied to solve problems in the field of reliability and safety of technical systems.
The paper presents a method for Ontology Design Patterns (ODP) engineering based on the transformation of conceptual models serialized in the XML-like formats. In this paper, we use UML class diagrams as the source of...
The paper presents a method for Ontology Design Patterns (ODP) engineering based on the transformation of conceptual models serialized in the XML-like formats. In this paper, we use UML class diagrams as the source of conceptual models. The method includes the following activities: design and serialization of a source conceptual domain model; analysis and transformation of an XML structure of a source conceptual model to an ontological schema model; transformation of an ontological schema model to a content ODP code in the OWL 2 DL format; verification and modification of obtained content ODPs by domain experts. All transformations are implemented with the use of original domain-specific language, namely, Transformation Model Representation Language (TMRL). The proposed method is used for ODPs engineering in tasks of industrial safety inspection of technical systems. Obtained ODPs can be used for knowledge bases and intelligent systems engineering.
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