Structural analysis is a methodological variety of system analysis. It was developed in the 60-70s of the XX century by Douglas T. Ross in the form of the SADT (Structured Analysis and Design Technique) methodology - a technology of structural analysis and design.
The structural analysis is based on revealing the structure as a relatively stable set of relationships, recognition of the methodological primacy of relations over elements in the system, and a partial distraction from the development of objects.

The main concept of structural analysis is a structural element (object) - an element that performs one of the elementary functions associated with the simulated object, process or phenomenon.

Structural analysis involves the study of the system using its graphical model representation, which begins with a general overview and then is detailed, acquiring a hierarchical structure with an increasing number of levels.

This approach is characterized by:

• splitting into levels of abstraction with a limitation of the number of elements at each level (usually from 3 to 9);
• limited context, including only details essential at each level;
• use of strict formal rules for recording;
• successive approximation to the final result.

The purpose of structural analysis is to transform general, vague knowledge of the source domain into exact models that describe the various subsystems of the simulated organization.

Decomposition (see the figure) is a conditional technique that allows you to present the system in a form convenient for perception, and evaluate its complexity. As a result of the decomposition of the subsystem, certain structural elements and the relationships between them are distinguished according to certain signs. Decomposition is a means of avoiding difficulties in understanding the system. The depth of decomposition is determined by the complexity and dimension of the system, as well as the objectives of the simulation.

Figure "Decomposition of the organization subsystem into structural elements"

The ARIS methodology also uses decomposition and allows you to refine the subject of modeling using alternative or complementary models.
It should be remembered that not a single subsystem can fully model business processes.
Therefore, to obtain a holistic picture of the organization's activities, it is necessary to take as a basis a description of one of the allocated structures and integrate it with the rest. As practice shows, the basis for such integration is most often a functional or informational subsystem.

Any organization, as a rule, has a large number of subsystems, so the number of structural elements and the relationships between them is very large.
Each structural element (or object) and connection have certain properties that must be described (see. Figure).
One of the varieties of properties are attributes. An attribute is a necessary, essential, inalienable property of an object. Naturally, different structural elements have different attributes.
Each object or relationship also has a set of characteristics (see the figure), with the help of which you can set the quantitative and qualitative characteristics of the modeled elements. In particular, for each function, you can specify its name, unique code in the project, author, time and date of creation, detailed description, implementation example, time and cost of performing this function, etc. All the specified characteristics of objects and relationships are formalized and used in the analysis or report.

Figure “Characteristics of structural elements and relationships”

Structural analysis methodology

Structural analysis as a set of large dimension due to complex systems modeling techniques tasks should be based on powerful computer support, providing automation systems analysts work. Such tools are CASE-systems (Computer Aided Software Engineering).
The architecture of most CASE-systems is based on the paradigm "methodology - model - notation - means" (see. Figure).
The methodology of structural analysis presents methods and tools for studying the structure and activities of an organization. It defines the basic principles and techniques of using models.
A model is a collection of symbols (mathematical, graphic, etc.) that adequately describes some properties of the modeled object and the relationship between them.
Notation - a system of conventions adopted in a particular model.
Means - hardware and software that implements the selected methodology, including the construction of appropriate models with the notation adopted for them.

When modeling systems in general and, in particular, for the purposes of structural analysis, various models are used that display:

• functions that the system must perform;
• processes ensuring the performance of these functions;
• data necessary for the performance of functions, and the relationship between these data;
• organizational structures that ensure the performance of functions;
• material and information flows arising during the performance of functions.

Figure "Architecture of CASE-systems"

Among the variety of tools provided for structural analysis, the most frequently and effectively used are:

• DFD (Data Flow Diagrams) —Diagrams of data flows in the notations of Heine-Sarson, Yordon-De Marco and others, providing the requirements of analysis and functional design of information systems;
• STD (State Transition Diagrams) - state transition diagrams based on Hartley and Ward-Mellor extensions for the design of real-time systems;
• ERD (Entity-Relationship Diagrams) - “entity-relationship” diagrams in Chen and Barker notations;
• Structural maps of Jackson and / or Constantine for the design of intermodular interactions and the internal structure of objects;
• FDD (Functional Decomposition Diagrams) - functional decomposition diagrams;
• SADT (Structured Analysis and Design Technique) - technology structural analysis and design;
• IDEF family (Integration Definition for Function Modeling).

IDEF family:

• IDEFO - functional modeling methodology, which is an integral part of SADT and allows you to describe a business process in the form of a hierarchical system of interrelated functions;
• IDEF1 - a methodology for the analysis and study of the relationship between information flows in the framework of a company’s commercial activities;
• IDEF1X is an information modeling methodology based on the concept of “entity-relationship” proposed by Chen. It is used to develop relational databases and uses conditional syntax specially designed for convenient construction of a conceptual scheme and providing a universal representation of the data structure within the enterprise, independent of the final implementation of the database and hardware platform;
• IDEF3 - a methodology for documenting technological processes, enterprises, which allows you to simulate their scenarios by describing the sequence of changes in the properties of the object within the process;
• IDEF4 - an object-oriented design methodology to support projects related to object-oriented implementations;
• IDEF5 is a methodology that provides a visual representation of the data obtained as a result of processing ontological queries in a simple, graphical form.

Using these methods, logical models of the initial and reorganized organization management systems can be built.

Model and modeling concepts

The created model should answer the following questions:

• Which of the organization's employees should perform specific functions?
• Under what conditions do you need to perform a function?
• What should an employee do as part of this function?
• How should it be carried out?
• What resources are needed?
• What are the results of the function?
• What information tools are needed?
• How to coordinate all this?
• How can all this be carried out most effectively?
• How can I change or build a business process?
• How to reduce risk and increase the effectiveness of changes?

Recall that the model is a set of objects and the relationships between them, which adequately describes only some of the properties of the simulated system.
The model is just one of many possible interpretations of the system. This interpretation should suit the user in a given situation, at a given point in time.

In the general case, the model is characterized by four properties:

• reduced scale (size) of the model, more precisely, its complexity, the degree of which is always less than that of the original. When constructing a model, simplifications are deliberately introduced;
• maintaining key relationships between different parts;
• operability, i.e. the ability in principle to work as an original-modeled object (in any case, in a similar way);
• adequacy to the actual properties of the original (degree of certainty).

It is also important to emphasize that any model reflects the point of view of a particular group of designers.

Each model has its own goals and objectives, and therefore a business object, which is a complex complex organism, is usually described by a certain set of models that together form the general model of this business system.

The use of many models leads to the need to classify them. A justified classification of objects is their conditional grouping according to specified criteria in accordance with a specific purpose. For different purposes, the same objects can be classified in different ways. Classification is not an end in itself, it is dictated by the needs of theory and practice.

An appropriate classification of models provides convenience when choosing modeling methods and obtaining the desired results.

The most important features by which the classification of models is carried out include:

1. the law of functioning and the characteristic features of the expression of the properties and relations of the original;
2. grounds for converting the properties and relationships of the model into the properties and relationships of the original.

According to the first sign, the models are divided into logical, material and semantic, or verbal.

Logical models operate according to the laws of logic in a person’s mind or in a computer running a program written by a person. Material models function in accordance with the objective laws of nature.

Semantic, or verbal, models are verbal descriptions of modeling objects. They are applied in a number of cases, in particular, at the initial stages of modeling the organization’s activities, during the survey by staff experts in order to obtain the necessary information.
The main problem that arises when constructing verbal models of an organization’s business processes is the establishment of effective interaction between domain experts (organization employees) and modeling experts.

The figurative, or iconic, models express the properties of the original with the help of visual images having prototypes among the objects of the material world. The ARIS model set includes several models that are essentially figurative or iconic. This, for example, the model "Production Process", "Office Process" and others.

Sign (symbolic) models express the properties of the simulated system using conventional signs or symbols. Figurative and iconic models combine the features of figurative and iconic models. The vast majority of ARIS models are figuratively iconic.

Functional, geometric and functional-geometric models reflect, respectively, only functional, only spatial and at the same time functional and spatial properties of the original. The ARIS methodology does not use these models.
By the second criterion, the models are divided into conditional, similar, and mathematical. Conditional models express the properties and relationships of the original on the basis of an accepted condition or agreement. In such models, similarity with the original may be completely absent. Almost all ARIS models are conditional. It should be noted that figurative and figurative-symbolic models are also conditional.

Similar models have similarities with the original, sufficient to go to the original on the basis of inference by analogy. Such models are also not used in ARIS.

Mathematical models provide the transition to the original, fixation and study of its properties and relationships using mathematical methods. Mathematical models have important advantages - clarity, the possibility of strict deduction, and verifiability. However, in a number of cases, when constructing mathematical models, for example, to describe the process of steel production, practically insurmountable difficulties may arise. Nevertheless, mathematical models are sometimes used in ARIS, in particular, in calculations during the functional-cost analysis. It is possible to qualify models depending on their purpose. From the point of view of taking into account the time factor, static, imitation and dynamic models are distinguished.

Static models describe the content side of the system that does not change over time. They can be functional informational, i.e. describe the structure of information on the basis of which the system functions, and structural, i.e. describe the structure of the system.

When modeling organizations, mainly conditional modeling is carried out, i.e. it is supposed to replace the original with a conditional model, representing it only within the framework of an agreement on the meaning attributed to this model. In this regard, the issue of notations used in symbolic and figurative-symbolic models is of great importance.

The following basic requirements are presented to model notation:

• simplicity - simple, ceteris paribus, preferable to complex;
• visibility - even the distant resemblance to the original facilitates the use of the model;
• individuality - sufficient contrast to other designations;
• unambiguity - the inadmissibility of designating one symbol of various objects;

Figure “Designation of objects in the ARIS knowledge structure diagram”

• uniformity - the application of similar rules in modeling homogeneous objects;
• certainty - clear rules for using the model;
• taking into account established traditions.

The notation of the graphic model suggests the presence of:

• a strictly defined set of interconnected graphic images - elements of a graphic language;
• various types of communication between them;
• fragments of text (natural language);
• embedded objects;
• glossary.

The graphic language provides the structure and exact semantics of the natural language of the model, organizes the natural language in a specific and unambiguous way, which allows us to describe very complex models.
The syntax of a graphic language contains, as a rule, multi-colored geometric figures (rectangles, squares, parallelograms, ellipses, triangles) and conditional images of various kinds.
Built-in objects - objects of other software systems (Word, Excel, mathematical packages) - improve the information richness of the model, make it more complete.
The glossary helps users understand the terminology of the model, thereby facilitating its understanding and use.

Stages of structural analysis

Carrying out a structural analysis of an organization involves several stages:

• building a hierarchy of goals to optimize the organization;
• choice of methodology;
• selection of models;
• analysis of the organization;
• development of models in accordance with the hierarchy of goals;
• model optimization;
• reorganization of activities.

At the first stage, the goals that are planned to be achieved during the structural analysis of the organization’s activities are identified and described. There are usually several of them. In this regard, the goals must be ranked, to build their hierarchy.
When the goals of the reorganization of activities are known, it becomes possible to choose methods for conducting structural analysis. Rigid selection algorithms do not exist. The structural analysis methodology involves the use of one or more models.
Having determined the objectives of the analysis and choosing the tools for its implementation, it is necessary to study in detail how the organization functions. The purpose of the study is to collect data for building models that reflect the activities of the organization.

The main principles of conducting a study of the organization are:

• purposefulness;
• complexity;
• regularity;
• organizational and methodological integrity.

The same principles should be implemented in a methodology that includes descriptions of the program of actions, the objects being studied, the degree of detail of the study, methods for collecting data and the rules for processing them. This technique provides a standardization of the study of the subject area and a formalized presentation of the data.
Information is collected within all the basic structures of the organization.
Most of the information collected is not obvious, formulated and unambiguous. In this regard, before starting the simulation, it is necessary to identify the main structure-forming elements of the control system of the analyzed organization and fix them. These items include:

• organizational structure of the company;
• territory structure;
• composition and structure of the main business processes of the company;
• classification and structure of the main working documents;
• classification and structure of information systems.

Organizational structure is the most obvious component of any company. However, there may be problems. So, the problem arises when there is a direct (disciplinary) subordination of one organizational element to another and at the same time an additional (functional) subordination. The most striking example is the bookkeeping of a large company with several lines of business. Accountants serving a certain area of ​​activity of such a company are part of a single accounting department and are subordinate (disciplined) to the chief accountant (sometimes to the financial director). However, functional subordination (within the basic functional responsibilities of accountants serving the direction) implies their subordination to the head of the functional unit (direction).

A characteristic problem is the existence of an informal subordination relationship.

Formally fixed subordination of some employees to others is often absent in practice. As a result, a new organizational structure appears, generally corresponding to the formal, but in certain parts different from it.
The third serious problem is the separation of the legal structure from the managerial one. This feature is typical primarily for holding companies that include several legal entities. The managerial structure (the subordination structure from the point of view of operational management) almost always differs significantly from the legal one. This is because there are different principles and criteria for the formation of managerial and legal structures.

The legal structure is formed from the point of view of the interests of strategic management, as well as from the point of view of the requirements of the business in which the organization is engaged.

The managerial structure is built and optimized in terms of more efficient operational management. As a result, specialists working on the basis of several legal entities can work in one unit (within the management structure).

The structure of the territory may turn out to be important for distributed organizations, where the territorial location of individual divisions (branches) significantly affects the features of the structure of the management system, in particular, business processes.

Despite the fact that in many organizations there are no clearly formulated regulatory documents that describe the rules for doing business and performing related procedures, the structure of the main and auxiliary processes of the top level can be determined, and this should be done at the very beginning of modeling work. This structure is to one degree or another identical for all companies engaged in similar activities. In this regard, it is possible to use existing generalized (reference) models of processes created for various industry areas.
The allocation of process structures will provide further more effective planning and management during the simulation, as well as facilitate the obtaining of structured information about the activities of the simulated organization.
One of the important tasks of increasing the effectiveness of the organization is to optimize document management and create a management accounting system. To solve this problem, it is necessary to have a structured classification system for the entire information space of the organization, including both documents and individual economic, financial, production and other indicators.

Formation of this structure - one of the highest priorities of modeling stages.
Tasks associated with the creation and implementation of information technology require a detailed analysis of existing information systems - their structure and participation in the organization's business processes. In this regard, it is necessary in advance, before detailed modeling of processes, to form a structured list of all information systems of interest, and also to evaluate their internal structure (first of all, a set of basic modules and screen forms).
Thus, in order to build an adequate and popular model of organization, it is necessary, at the initial stages of modeling, to think about isolating and fixing all the fundamental structures. Their competent formation provides a quality "reserve" for the future. This will allow thoughtfully and predictably to develop all new detailed models that have a certain place in the general model of the structure of the organization and correspond to the objectives of the analysis of individual elements and the organization as a whole.
The quality and quantity of information obtained during the study of the organization depends on how adequate the constructed model will be.

The development of models of the organization includes several stages:

• the selection of many objects that have a significant impact on the activity of the structural element;
• specification of input and output streams (information, materials, products, services, finance, etc.);
• identification of the main processes that determine the activity of the structural element and ensure the implementation of its target functions;
• specification of flows between the main processes of activity, clarification of the links between processes and external objects;
• assessment of volumes, intensity and other necessary characteristics of flows;
• development of a functional model of the structural element;
• combining models of structural elements into a single model of the organization.

The constructed model should be optimized according to criteria of interest to the user. After that, an analysis of the models is carried out, the results of which are used to reorganize the activities.