Nauka ta progres transportu (Oct 2019)
FORMALIZATION OF THE TECHNOLOGICAL PROCESSES AT RAILWAY STATIONS BASED ON THE STEP-BY-STEP MODELING
Abstract
Purpose. Specialized software must be used to represent the technological process using step-by-step modeling methodology. Formalizing the technological process is one of the main tasks in the design or optimization phase of a railway station. The article proposes to develop a methodology of formalizing the technological processes based on the step-by-step modeling. Methodology. Using the methodology of stage-by-stage design, the input, internal and initial model of the railway station's operation were constructed. The input model of the proposed method is formed by the use case diagram, the statechart and activities diagrams, which are constructed using the tools of the IBM Rational Rose software. This model provides a graphoanalytic representation of the technological processes of a railway station with its visual control, which avoids time-consuming manual coding and eliminates errors. The diagrams below describe the technological process of a railway station based on hierarchical diagrams of the sequence of works of different detail degrees. Both initial and internal models are constructed using a unified UML modeling language. The methods of object-oriented design, finite state machines and system programming are used as research methods. Findings. The proposed methodology will make it possible to construct simulation models of railway stations using Harel statecharts. These models represent a hierarchically organized set of interacting finite state machines, while the complex model at each level of the hierarchy retains a simple and accessible structure. The start and finish signals generated by the state transition allow the model to be synchronized, and the use of state and signal description actions (UML extension) makes it possible to use external algorithms where the usual/automatic formalism becomes inconvenient. And the methodology implemented by means of the UML language, significantly facilitates the presentation and perception of the station model. Originality. The methodology of presenting a functional model of railway stations with the use of visual design methods has been improved. Practical value. The proposed method is intended for semigraphical representation of technological process of railway station operation, using the methodology of step-by-step modeling. Modeling on the basis of a graphical input model constructs internal and output models, as well as presents the methods for their transformations.
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