1. Visual modeling and UML

Visual modeling (visual modeling) is a way of presenting ideas and problems of the real world using models [1].

A model is an abstraction that describes the essence of a complex problem or structure without focusing on irrelevant details, thereby making it more understandable.

Software development is no exception. When building a complex system, its abstract visual models are built.

Currently in the field of information systems design

Suspension applies visual modeling using a unified modeling language UML.

The Unified Modeling Language (UML) is a graphical language for visualizing, specifying, constructing and documenting systems in which software plays a major role [2].

Using UML, you can describe the system in detail, starting development with a conceptual model with its business functions and processes, as well as describe system implementation features, such as system software classes, database schema. Using UML, we can also develop complex systems quickly and efficiently.

As a graphical visual modeling language, UML has its own connotation - the accepted notation. The notation provides the semantics of the language, is a way to unify the notation of visual modeling, provides a comprehensive presentation of the system, which is relatively easily and freely perceived by man. The latest version of the UML 2.4.1 notation was published in August 2011.

Modeling using UML is carried out by phased construction of a number of diagrams, each of which reflects some part or side of the system or its design.

A diagram is a graphical representation of a set of elements. Typically, a diagram is depicted as a graph with vertices (entities) and edges (relations). Charts are subject to UML notation and are depicted in accordance with it.

Basic UML diagrams:

 use cases (use case diagram);

Classes (class diagram);