IDEF0. Familiarity with the notation and an example of its use. BPwin (AllFusion Process Modeler) computer modeling software idef0 model development software

Known today not only in narrow circles, the abbreviation IDEF0 is the first methodology to standardize work on business processes. It was developed in the middle of the last century as part of an aerospace project in the United States and, having shown its effectiveness, became federal standard... In our country in 2000, a document was prepared " Functional Modeling Methodology IDEF0. Guidance document Functional Modeling Methodology IDEF0 Guidance Document. Official edition. Gosstandart of Russia RD IDEF0 - 2000. Developed by the Research Center CALS - Technologies "Applied Logistics". Adopted and put into effect by the Resolution of the Gosstandart of Russia 2000, Moscow”, But as a standard it was never approved. Although this did not prevent this methodology from becoming one of the most popular tools for graphical modeling of business processes in our country. In this article, I invite you to review the IDEF0 model and assess the current relevance of this approach.

Basic concepts and abbreviations

Let's understand a little about the names of the key elements of the methodology. The IDEF0 graphic standard is part of the SADT (Structured Analysis and Design Technique) methodology. IDEF is an abbreviation for ICAM Definition, and ICAM is derived from Integrated Computer Aided Manufacturing, which translates as integrated computerization of production. The SADT methodology is a whole family of 15 different models, which together were supposed to allow the study of the structure, parameters and characteristics of production-technical and organizational-economic systems.

IDEF0 is a functional model, which is the core of all other structures, it links together information and material flows, organizational structure, control actions and the very activity of the company. The graphical standard for modeling processes is also called notation. That is, notation is a system of requirements and rules for constructing an activity model in one form or another. Therefore, it is appropriate to call IDEF0 the notation that is part of the SADT methodology.

IDEF0 notation is a fairly rigorous technique that was originally developed, like technical design standards, for manual modeling. Therefore, it contains requirements for the placement of arrows, the format of all elements, the content of the information frame for the IDEF0 diagram, etc. Since the company's activities are a complex multi-level system of actions, there are always many schemes, and an unambiguous systematization and navigation through all elements of the model is required. Now this is done mainly by computer systems that support modeling in this notation. On the territory of Russia, the most famous and available today are the AllFusion Process Modeler and Business Studio systems. I plan to devote separate articles to the review of these systems.

Functional block

The central element of the IDEF0 model is the function, which is displayed on the diagram as functional block- a rectangle, inside which the action is indicated in the form of a verbal noun. The action can be very different in scale - from the activities of the company in general and to specific manipulation in particular. Examples: "Production and sale of ceramic tableware" and "Drawing on a product".

Mandatory function block elements in IDEF0

Regardless of the scale of actions, all functions are displayed uniformly and necessarily contain 4 key streams, which are rigidly assigned to the sides of the functional block:

on the left - inputs or resources used to perform the function;
on the right - outputs or results of the function execution;
on top - control actions that determine how and how many results should be produced;
below - mechanisms that reflect who and with the help of what should do this work.

This approach allows you to save a little on explanations in the diagrams and to achieve unambiguity in the display of flows, which makes the whole model slender.

To build a functional model, the IDEF0 methodology requires the following rules to be observed.

Inputs are resources that transfer their value to outputs completely, that is, they are spent on creating a result in full, and mechanisms are resources that transfer their value only partially (equipment through depreciation, and people through wages).
Management is a necessary element of the model, since it binds all actions to the company's system of regulations, clearly indicating which rules and requirements must be observed in the process of performing the function. Often this flow is treated formally, but the scheme loses its rigor and sometimes even meaning.
Each functional block must have at least one arrow on each side (since there can be no work without resources or results, and an instruction without an executor or instruction will be incomplete).

The considered scheme is a “building block” of the IDEF0 approach. Functional modeling involves a gradual transition from the general to the particular through decomposition. Decomposition is "deepening" into the function under consideration, dividing it into smaller functions. At the same time, when the top-level function is presented in a generalized manner and after it is decomposed, it is appropriate to call it a process.

Context diagram

At the highest level, the company is presented as a "black box" in which some activity takes place, which translates entrances to exits. This level is usually called "", that is, a diagram describing the context of the company's activities. Additionally, the context diagram displays the key characteristics of the entire model.

The goal is a specific formulation of the purpose of the model, by which the accuracy of the model construction can be checked in the future.
Point of view - on whose face the model is built, since the model is always dependent on its author and focus of attention. If we build a general model of an enterprise, then it is usually presented from the point of view of its director.
The model type is an indication of what information is displayed on the diagrams. There can be 2 principal options: AS IS ("as is") or TO BE ("as will be"). This separation is necessary, since we can build models both for analyzing activities and for transforming them. We must be clearly aware of what we are doing, and also convey this information to others.

Thus, the context diagram contains in the most generalized form a description of the company's activities, which is permeated by the flows connecting the company with the outside world. I think we should also dwell on them in more detail.

Main streams

Experience has shown that, despite the seeming simplicity and formality of this level, it is often necessary to stay at it for a long time, since all the results that are significant for the owner and the market must be reflected here. An error can lead to the creation of models that do not fulfill the business objectives. To verify that significant flows are reflected, make sure that all 4 main flow types are present in your diagram.

Material: materials and components at the entrance and finished products at the exit.
Customer: a potential customer entering and a satisfied customer.
Financial: at the entrance, these are usually investments, customer payments (revenue), loans and other income; the output is payments to suppliers, taxes, loan payments and profits.
Informational: at the input, these are all flows of information about the external environment (market conditions, competitors' behavior, technological innovation etc.), and the output is the flow of information that the company communicates about itself to the world (all advertising information, as well as all types of reporting to regulatory authorities).

Please note that the company is open system, and nothing arises or disappears in it. A company is only able to transform incoming flows into outgoing ones, and if it does it well, then an additional cash flow (profit) appears, reflecting, in a sense, the quality of the entire system.

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It is good if you highlight each of these types of flows with your own color so that you can easily distinguish the movement of resources and do not miss important points. For example, it is often possible to observe the absence of a client in the company's flows, therefore, work with him is based on a leftover principle - the client often feels like an obstacle for the company's employees, whose tasks are focused on processing the flow of documents.

Control arrows can be represented by only 1 type of flow - information flow, which can be divided into 2 subspecies. The first is documents such as:

laws and regulations;
orders, orders;
instructions and regulations;
plans;
design documentation, etc.

The second is undocumented information, which most often includes the requirements of the owners.

And, finally, mechanisms - there are only 2 types of flows: equipment (material) and performers (departments and people). There can be no documents here, just as there can be no people on the control arrows!

The model provides continuous numbering for navigation. The context diagram is numbered "A-0". In the future, each functional block gets its own number, no matter how deep the decomposition is.

Decomposition

After working out the flows of the context diagram, we can proceed to decomposition. Moving to a level below, as if opening a "black box", we first see a blank sheet with arrows that have been attached to the functional block.

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And here the actual functional modeling begins - we must understand what set of actions can connect these flows and ensure that all the requirements are met. The difficulty lies in the fact that there are a lot of actions in the company, and on the diagram we have the right to display no more than 9 functions, otherwise the diagram will become unreadable and, accordingly, useless.

It is not always easy to arrange complex activities in such a way that they remain visual, readable, and at the same time complete. Most often, they resort to dividing the entire variety of processes into main large blocks, the most significant of which are the following.

Creation of a product (result).
Promotion and sale - working with customer flow.
Support for product creation activities are secondary processes that are necessary to comply with government requirements or to ensure the convenience of work (personnel and accounting, transport services, cleaning of premises, etc.).
Creation of management flows - the activity of developing management solutions that will determine the requirements for all processes of the company.

The figure below shows the decomposition diagram of our example.

(click to enlarge)

In the diagram, the processes should be arranged diagonally - this is called dominance principle, which implies the arrangement of functional blocks from left to right and from top to bottom - in order of importance or in chronological order. Block numbering is the same.

Further work on the model is similar to the first step - each functional block of the first level is decomposed. The block numbering will contain the number of the first level: A1.1… A1n, A2.1… A2.n, etc.

Conclusions about the relevance of the notation

Within the framework of this article, it was possible to display only the basic concepts of IDEF0 notation using a short example of IDEF0, by which, of course, it is difficult to judge the methodology as a whole. But quite a lot of experience in using this notation in practice allows me to draw the following conclusions.

The model has good visualizing potential, but, in my opinion, its greater importance is in the disciplining effect. The rules and limitations embedded in the methodology force us to develop a systematic and strict attitude to the models, which has a very good effect on the quality of the final result.
The model allows you to build communication flows between seemingly not strongly connected things: to connect the front and back office subsystems with management, which is much worse for other notations.
The approach is simple and straightforward for most of the project participants. Building and reading diagrams in this notation is limited only by the desire to delve into the intricacies of business flows.

Some of the above arguments make one think that this approach is the best and only one for a complete modeling of activities. But do not forget that the functional model is designed only for the upper level of modeling. The use of the IDEF0 notation for the design of work at the performer level leads to the fact that the diagrams are purely illustrative and on their basis it is impossible to build a sensible regulation, since they do not contain:

concretizing the events of starting and stopping the process;
conditions for the transition from one action to another;
the ability to visually display all resources and performers without overloading the diagram with arrows.

Therefore, if you use this notation for the tasks for which it is intended (structuring top-level activities), then IDEF0 is practically the only notation for today that allows you to do this meaningfully and accurately.

V project management this modeling standard is most applicable where you need to link different projects or processes with visual flows. At the same time, the graphical model will make it possible to more rationally distribute responsibility and resources by tasks. The logic of the project's tasks, reflected in the diagrams, will help prepare a better quality calendar plan in the form of a Gantt chart.

Learn to see and understand the functional structure of your business!

At present, in Russia, interest in the generally accepted standards of management in the West has sharply increased, however, in real management practice, there is one very indicative moment. Many leaders can still be baffled by the direct question of organizational structure company or about the scheme of existing business processes. The most advanced managers who regularly read economic periodicals, as a rule, begin to draw hierarchical diagrams that are understandable only to them, but in this process they usually quickly come to a dead end. The same applies to employees and managers of various services and functional units. In most cases, the only set of rules set out in accordance with which an enterprise should operate is a set of individual provisions and job descriptions... Most often, these documents were drawn up more than one year ago, are poorly structured and not interconnected and, as a result, are simply gathering dust on the shelves. For the time being, such an approach was justified, since during the formation of the Russian market economy, the concept of competition was practically absent, and there was no particular need to consider costs - the profit was gigantic. As a result, over the past two years, we have seen a completely understandable picture: large companies that grew in the early 90s are gradually losing their positions, right up to their complete withdrawal from the market. This is partly due to the fact that the enterprise did not implement management standards, the concept of a functional model of activity and mission was completely absent. With the help of modeling various areas of activity, it is possible to efficiently analyze bottlenecks in management and optimize the overall business scheme. But, as you know, at any enterprise, only those projects that directly bring profit are of the highest priority, therefore, it is usually only during a tangible crisis in the management of the company that we are talking about the survey of activities and its reorganization.

At the end of the 90s, when the market was sufficiently competitive and the profitability of enterprises began to fall sharply, managers felt enormous difficulties in trying to optimize costs so that products remained both profitable and competitive. It was at this moment that the need to have before your eyes a model of the enterprise's activity that would reflect all the mechanisms and principles of the interconnection of various subsystems within the framework of one business was clearly manifested.

The very concept of "modeling business processes" came into the everyday life of most analysts simultaneously with the appearance on the market of complex software products designed for complex automation of enterprise management. Such systems always imply a deep pre-project survey of the company's activities. The result of this survey is an expert opinion, in which individual points are made recommendations for elimination " bottlenecks”In the management of activities. On the basis of this conclusion, immediately before the implementation of the automation system, the so-called reorganization of business processes is carried out, sometimes quite serious and painful for the company. This, and naturally, a team that has developed over the years is always difficult to force to “think in a new way”. Such complex surveys of enterprises are always complex and significantly different tasks from case to case. There are well-tried methodologies and standards for solving such problems of modeling complex systems. These standards include the methodologies of the IDEF family. With their help, it is possible to effectively display and analyze the models of the activity of a wide range of complex systems in various sections. At the same time, the breadth and depth of examination of the processes in the system is determined by the developer himself, which allows not to overload the created model with unnecessary data. V currently The following standards can be attributed to the IDEF family:

IDEF0 is a functional modeling methodology. With the help of the visual graphical language IDEF0, the system under study appears to developers and analysts in the form of a set of interrelated functions (functional blocks - in terms of IDEF0). Typically, IDEF0 modeling is the first step in learning about any system;

IDEF1 - a methodology for modeling information flows within the system, which allows you to display and analyze their structure and relationships;

IDEF1X (IDEF1 Extended) is a methodology for building relational structures. IDEF1X belongs to the type of methodologies "Entity-relationship" (ER - Entity-Relationship) and, as a rule, is used to model relational databases related to the system in question;

IDEF2 is a methodology for dynamic modeling of systems evolution. Due to the very serious difficulties of analyzing dynamical systems, this standard was practically abandoned, and its development was suspended at the very initial stage. However, at present there are algorithms and their computer implementations that make it possible to transform a set of static IDEF0 diagrams into dynamic models based on “colored Petri nets” (CPN - Color Petri Nets);

IDEF3 is a methodology for documenting the processes occurring in the system, which is used, for example, in the study of technological processes in enterprises. IDEF3 describes the scenario and workflow for each process. IDEF3 has a direct relationship with the IDEF0 methodology - each function (functional block) can be represented as a separate process by means of IDEF3;

IDEF4 is a methodology for building object-oriented systems. IDEF4 tools allow you to visually display the structure of objects and the underlying principles of their interaction, thereby allowing you to analyze and optimize complex object-oriented systems;

IDEF5 is a methodology for the ontological study of complex systems. Using the IDEF5 methodology, the ontology of a system can be described using a specific vocabulary of terms and rules, on the basis of which reliable statements about the state of the system under consideration at a certain point in time can be formed. Based on these statements, conclusions are drawn about further development system and its optimization is carried out.
In this article, we will look at the most commonly used functional modeling methodology IDEF0.

The history of the IDEF0 standard

The IDEF0 methodology can be considered the next stage in the development of the well-known graphical language for describing functional systems SADT (Structured Analysis and Design Teqnique). Several years ago, a small edition of the book of the same name was published in Russia, which was devoted to describing the basic principles of constructing SADT diagrams. Historically, IDEF0 as a standard was developed in 1981 as part of an extensive automation program industrial enterprises, which bore the designation ICAM (Integrated Computer Aided Manufacturing) and was proposed by the US Air Force. The IDEF family of standards itself inherited its designation from the name of this program (IDEF = ICAM DEFinition). In the process of practical implementation, the participants of the ICAM program faced the need to develop new methods for analyzing interaction processes in industrial systems. At the same time, in addition to an improved set of functions for describing business processes, one of the requirements for the new standard was the availability of an effective methodology for interaction within the “analyst-specialist” framework. In other words, the new method was supposed to provide group work on the creation of the model, with the direct participation of all analysts and specialists involved in the project.

As a result of the search for appropriate solutions, the IDEF0 functional modeling methodology was born. Since 1981, the IDEF0 standard has undergone several minor changes, mostly of a limiting nature, and its last revision was released in December 1993 by the US National Institute for Standards and Technology (NIST).

Basic elements and concepts of IDEF0

The graphic language IDEF0 is surprisingly simple and harmonious. The methodology is based on four main concepts.

The first is the concept of an Activity Box. A functional block is graphically depicted in the form of a rectangle (see Fig. 1) and personifies some specific function within the framework of the system under consideration. According to the requirements of the standard, the name of each functional block must be formulated in the verb mood (for example, “produce services”, not “production of services”).

Each of the four sides of a functional block has its own specific meaning (role), while:

The top side is Control;

The left side is set to “Input”;

The right side is set to “Output”;

The underside is “Mechanism”.

Each functional block within the framework of a single considered system must have its own unique identification number.

Figure 1. Functional block.

The second “whale” of the IDEF0 methodology is the concept of an interface arc (Arrow). Also, interface arcs are often called streams or arrows. The interface arc displays a system element that is processed by a function block or otherwise affects the function displayed by this function block.

The graphical display of the interface arc is a unidirectional arrow. Each interface arc must have its own unique name (Arrow Label). As required by the standard, the name must be a noun turnover.

With the help of interface arcs, various objects are displayed that, to one degree or another, determine the processes taking place in the system. Such objects can be elements of the real world (parts, cars, employees, etc.) or streams of data and information (documents, data, instructions, etc.).

Depending on which of the sides this interface arc is suitable for, it is called “inbound”, “outbound” or “control”. In addition, only functional blocks can be the “source” (beginning) and “sink” (end) of each functional arc, while the “source” can only be the output side of the block, and the “sink” can be any of the three remaining ones.

It should be noted that any functional block, according to the requirements of the standard, must have at least one control interface arc and one outgoing one. This is understandable - each process must follow some rules (displayed by the control arc) and must produce some result (outgoing arc), otherwise it makes no sense to consider it.

When constructing IDEF0 - diagrams, it is important to correctly separate the incoming interface arcs from the control ones, which is often not easy. For example, figure 2 shows the function block “Process workpiece”.

In a real process, the worker performing the processing is given a workpiece and technological instructions for processing (or safety rules when working with the machine). It may be a mistake to think that both the workpiece and the document with technological instructions are incoming objects, but this is not so. In fact, in this process, the workpiece is processed according to the rules reflected in the technological instructions, which should be respectively displayed by the control interface arc.

Figure 2.

Another thing is when technological instructions are processed by the chief technologist and changes are made to them (Fig. 3). In this case, they are displayed as an already incoming interface arc, and the control object is, for example, new industrial standards, based on which these changes are made.

Figure 3.

The above examples emphasize the seemingly similar nature of incoming and outgoing interface arcs, but there are always certain distinctions for systems of the same class. For example, in the case of considering enterprises and organizations, there are five main types of objects: material flows (parts, goods, raw materials, etc.), financial flows (cash and non-cash, investments, etc.), document flows (commercial, financial and organizational documents), information flows (information, data of intent, oral instructions, etc.) and resources (employees, machines, machines, etc.). In this case, in various cases, all types of objects can be displayed by incoming and outgoing interface arcs, which control only those related to the flows of documents and information, and only resources can be displayed by arcs-mechanisms.

The obligatory presence of control interface arcs is one of the main differences of the IDEF0 standard from other methodologies of the DFD (Data Flow Diagram) and WFD (Work Flow Diagram) classes.

The third basic concept of the IDEF0 standard is Decomposition. The decomposition principle is used when breaking down a complex process into its constituent functions. In this case, the level of detail of the process is determined directly by the model developer.

Decomposition allows you to gradually and structured represent the system model in the form of a hierarchical structure of individual diagrams, which makes it less congested and easy to digest.

The IDEF0 model always starts with the presentation of the system as a whole - a single functional block with interface arcs extending beyond the considered area. Such a diagram with one functional block is called a context diagram, and is denoted by the identifier “A-0”.

The explanatory text for the context diagram must indicate the Purpose of building the diagram in the form of a brief description and fix the point of view (Viewpoint).

Defining and formalizing the development goal of IDEF0 - the model is extremely important point... In fact, the goal identifies the relevant areas in the system under study that should be focused on first. For example, if we model the activities of an enterprise in order to build an information system on the basis of this model in the future, then this model will differ significantly from the one that we would develop for the same enterprise, but with the aim of optimizing supply chains.

The point of view defines the main direction of development of the model and the level of detail required. A clear fixation of the point of view allows you to unload the model, abandoning the detailing and research of individual elements that are not necessary, based on the chosen point of view on the system. For example, the functional models of the same enterprise from the point of view of the chief technologist and the financial director will differ significantly in the direction of their detailing. This is due to the fact that, ultimately, the CFO is not interested in the aspects of processing raw materials on production machines, and the chief technologist does not need drawn diagrams. financial flows... The correct choice of point of view significantly reduces the time spent on building the final model.

In the process of decomposition, the functional block, which in the context diagram displays the system as a whole, is drilled in another diagram. The resulting diagram of the second level contains functional blocks that display the main subfunctions of the functional block of the context diagram and is called a child diagram (Child diagram) in relation to it (each of the functional blocks belonging to a child diagram is respectively called a child block - Child Box). In turn, the parent function block is called the parent block in relation to the child diagram (Parent Box), and the diagram to which it belongs is called the parent diagram (Parent Diagram). Each of the sub-functions of the child diagram can be further detailed by a similar decomposition of the corresponding functional block. It is important to note that in each case of decomposition of a functional block, all interface arcs included in this block or outgoing from it are fixed in the child diagram. This achieves the structural integrity of the IDEF0 model. The principle of decomposition is clearly shown in Figure 4. You should pay attention to the relationship between the numbering of functional blocks and diagrams - each block has its own unique serial number on the diagram (the number in the lower right corner of the rectangle), and the designation at the right angle indicates the number of the child diagram for this block ... The absence of this designation means that there is no decomposition for this block.

There are often cases when individual interface arcs do not make sense to continue to be considered in child diagrams below a certain level in the hierarchy, or vice versa - individual arcs have no practical meaning above a certain level. For example, an interface arc depicting a “detail” at the entrance to the function block “Process on lathe”Does not make sense to reflect on the diagrams of higher levels - it will only overload the diagrams and make them difficult to understand. On the other hand, there is a need to get rid of separate “conceptual” interface arcs and not detail them deeper than a certain level. To solve such problems, the IDEF0 standard provides for the concept of tunneling. The Arrow Tunnel designation in the form of two parentheses around the beginning of the interface arc denotes that this arc was not inherited from the functional parent block and appeared (from the "tunnel") only in this diagram. In turn, the same designation around the end (arrow) of the interface arc in the immediate vicinity of the receiver block means the fact that in the child diagram of this block this arc will not be displayed and will not be considered. Most often it happens that individual objects and their corresponding interface arcs are not considered at some intermediate levels of the hierarchy - in this case, they are first “plunged into the tunnel” and then, if necessary, “returned from the tunnel”.

The last of the IDEF0 concepts is the Glossary. For each of the IDEF0 elements: diagrams, functional blocks, interface arcs, the existing standard implies the creation and maintenance of a set of relevant definitions, keywords, narratives, etc. that characterize the object displayed by this element. This set is called a glossary and is a description of the essence of this element. For example, for the “payment order” control interface arc, the glossary may contain a list of fields of the document corresponding to the arc, the required set of visas, etc. The glossary harmoniously complements the graphical language, providing the diagrams with the necessary additional information.

Figure 4. Decomposition of functional blocks.

Principles of limiting the complexity of IDEF0 diagrams

Typically, IDEF0 models carry complex and concentrated information, and in order to limit their congestion and make them readable, the corresponding complexity limits are adopted in the corresponding standard:

Limiting the number of functional blocks in the diagram to three to six. The upper limit (six) forces the designer to use hierarchies when describing complex items, and the lower limit (three) ensures that there is enough detail on the corresponding diagram to justify its creation;

Limiting the number of interface arcs suitable for one functional block (leaving one functional block) to four.
Of course, it is not at all necessary to strictly follow these restrictions, however, as experience shows, they are very practical in real work.

Discipline of group work on the development of the IDEF0-model

The IDEF0 standard contains a set of procedures that allow a large group of people from different areas of the modeled system to develop and agree on a model. Typically, the development process is iterative and consists of the following conditional stages:

Creation of a model by a group of specialists related to various areas of the enterprise. This group is called Authors in terms of IDEF0. Building an initial model is a dynamic process during which authors ask competent people about the structure of various processes. Based on the existing provisions, documents and survey results, a draft (Model Draft) of the model is created.

Distribution of the draft for review, approvals and comments. At this stage, there is a discussion of the draft model with a wide range of competent persons (in terms of IDEF0 readers) in the enterprise. At the same time, each of the diagrams of the draft model is criticized and commented in writing, and then transferred to the author. The author, in turn, also agrees in writing with the criticism or rejects it, outlining the logic of decision-making and returns the revised draft for further consideration. This cycle continues until the authors and readers come to a consensus.

Model approval. The approved model is approved by the head of the working group in the event that the authors of the model and the readers have no disagreements about its adequacy. The final model is a consistent view of the enterprise (system) from a given point of view and for a given purpose.
The visibility of the IDEF0 graphic language makes the model quite readable for persons who did not take part in the project of its creation, as well as effective for holding shows and presentations. In the future, on the basis of the constructed model, new projects can be organized aimed at making changes in the enterprise (in the system).

Features of the national practice of using functional modeling by means of IDEF0

V last years interest in the methodologies of the IDEF family is growing steadily in Russia. I constantly observe this, looking at the statistics of calls to my personal web page (http://www.vernikov.ru), which briefly describes the basic principles of these standards. At the same time, I would call interest in such standards as IDEF3-5 theoretical, and in IDEF0 quite practically justified. As a matter of fact, the first Case-tools allowing to build DFD and IDEF0 diagrams appeared on the Russian market back in 1996, simultaneously with the release of the popular book on the principles of modeling in the SADT standards.

Nevertheless, most executives still regard the practical application of modeling in IDEF standards more as a tribute to fashion than an effective way of optimization. the existing system business management. This is most likely due to a pronounced lack of information on the practical application of these methodologies and the inevitable software bias of the vast majority of publications.

It is no secret that almost all projects for the survey and analysis of financial and economic activity enterprises now in Russia are in one way or another associated with the construction of automated control systems. Thanks to this, the IDEF standards, in the understanding of the majority, have become conditionally inseparable from the implementation of information technologies, although with their help it is sometimes possible to effectively solve even small local problems, literally with the help of a pencil and paper.

When conducting complex enterprise survey projects, the development of models in the IDEF0 standard allows you to visually and effectively display the entire mechanism of enterprise activity in the desired context. Most important, however, is the collaboration that IDEF0 provides. In my practice, there were quite a few cases when the construction of the model was carried out with the direct help of employees of various departments. At the same time, the consultant in a fairly short time explained to them the basic principles of IDEF0 and taught them to work with the corresponding applied software... As a result, employees of various departments created IDEF diagrams of the activities of their functional unit, which were to answer the following questions:

What goes to the unit “at the entrance”?

What functions, and in what sequence, are performed within the unit?

Who is responsible for each of the functions?

What is the executor guided by when performing each of the functions?

What is the result of the unit's work (output)?

After agreeing on draft diagrams within each specific department, they are assembled by the consultant into a draft enterprise model, in which all input and output elements are linked. At this stage, all the discrepancies of individual diagrams and their controversial places are recorded. Further, this model again passes through the functional departments for further coordination and making the necessary adjustments. As a result, in a fairly short time and with the involvement of a minimum of human resources from a consulting company (and these resources, as you know, are very expensive), an IDEF0-model of an enterprise is obtained according to the “As is” principle, and, more importantly, it represents an enterprise with positions of employees who work in it and thoroughly know all the nuances, including informal ones. In the future, this model will be transferred for analysis and processing to business analysts who will look for bottlenecks in company management and optimize key processes, transforming the “As is” model into the corresponding “As should be” view. Based on these changes, a final conclusion is made, which contains recommendations for reorganizing the management system.

Of course, such an approach requires a number of organizational measures, primarily on the part of the management of the surveyed enterprise. This is due to the fact that this technique involves the assignment of some employees additional responsibilities on the development and practical application of new methodologies. However, in the end, this pays off, since the additional one or two hours of work of individual employees over several days can significantly save money on paying for consulting services to a third-party company (which in any case will tear away from the work of the same employees with questionnaires and questions). As for the employees of the enterprise themselves, in one way or another, I have not met any expressed opposition on their part.

The conclusion from all this can be done as follows: it is not at all necessary to come up with solutions for standard problems every time. Whenever you are faced with the need to analyze a particular functional system (from a spacecraft design system to the process of preparing a complex dinner), use methods that have been tried and tested over the years. One of these methods is IDEF0, which allows you to solve complex life problems with the help of its simple and understandable tools.

IDEF0 diagrams are built using the BPWin program. They are intended for graphical modeling of ongoing business processes.

About IDEF0 methodology

The IDEF0 methodology is widely used due to its simple and easy-to-understand graphical notation, which is very convenient for building a model. The main place in the methodology is given to diagrams. The diagrams display the functions of the system by means of geometric rectangles, as well as the existing connections between functions and the external environment. Links are shown using arrows. You can verify this by seeing what the IDEF0 diagram offers, examples of which can be found in this article.

The fact that only two graphical primitives are used in modeling allows you to quickly explain the current rules of IDEF0 interactions to those people who have no idea about it.With IDEF0 diagrams, the customer's connection to the ongoing processes is carried out more quickly thanks to the use of a visual graphics language. You can see what the IDEF0 diagram offers, examples of which are presented below.

Elements used for IDEF0

As already mentioned, 2 types of geometric primitives are used: rectangles and arrows. Rectangles represent certain processes, functions, work or tasks that have goals and lead to the indicated result. The interaction of processes with each other and the external environment is indicated by arrows. IDEF0 distinguishes 5 different types of arrows.

Possibilities of using IDEF0

The IDEF0 methodology can be applied to describe the functional aspect of any information system.

Types of links between IDEF0 processes

It is in the interests of the model to create such connections of constructions so that internal connections are as strong as possible, and external ones - as weak as possible. it strong point modeling with IDEF0. You can see examples of diagrams for yourself and be convinced of the veracity of these words. To facilitate the establishment of connections, these are connected into modules. External links are established between the modules, and internal links are established inside the modules. There are several types of links.

1. Hierarchical ("part" - "whole") relationship.

2. Manager (regulatory, subordinate):

2) feedback control.

3. Functional or technological:

2) reverse input.

3) consumer;

4) logical;

5) methodical or collegial;

6) resource;

7) informational;

8) temporary;

9) random.

Building blocks and links in diagrams

The IDEF0 methodology provides a number of rules and guidelines for its use and improving the quality of use. So, the diagram displays one block on which you can specify the name of the system, its purpose. 2-5 arrows lead to the block or from the block. More or less may be possible, but at least two arrows are needed to enter / exit, and the rest for additional work and their indications in the diagram. If the arrows are more than 5, you should think about the optimality of building the model, and whether it is possible to make it even more detailed.

Building Blocks in Decomposition Diagrams

The number of blocks that will be on one diagram is recommended in the number of 3-6. If there are fewer of them, then such diagrams are unlikely to carry a semantic load. If the number of blocks is huge, then it will be very difficult to read such a diagram, given the presence of additional arrows. To improve the perception of information, it is recommended to place blocks from top to bottom and from left to right. This arrangement will reflect the logic of the execution of the sequence of processes. And also arrows will create less confusion, having a minimum number of intersections with each other.

If the launch of a certain function is not controlled in any way, and the process can be started at an arbitrary moment, then such a situation is indicated by the absence of arrows indicating control and entry. But the presence of such a situation can tell potential partners about certain instability and the need to take a closer look at the potential partner.

A block that only has an input arrow indicates that the process receives input parameters, but no control or adjustment occurs at runtime. A block that only has a control arrow is used to indicate jobs that are called only by special order of the control system. They are controlled and adjusted at all their stages.

But an example of building an IDEF0 diagram can convince that the most complete and encompassing type is the diagram with entry and control arrows.

Naming

To improve the visual experience, each block and each arrow should have its own name, which will allow you to identify them among many other blocks and arrows. This is how the sample diagrams look in IDEF0. Information system, built with the help of them, will allow you to understand all the shortcomings and complexities of the models.

Arrow fusion is often used, and questions arise about their naming. But merging is possible only in case of transferring homogeneous data, so separate names are not needed, although they can be specified in BPWin. Also, if there is a divergence of the arrows, then they can be separately named in order to understand what is responsible for what.

If there is no name after the branch, then the name is considered to be exactly as it was before the branch. This may be the case if two blocks require the same information. The IDEF0 context diagram, an example of which can be found in this article, will confirm these words.

Arrow information

Arrows entering and leaving the same block when building a composition diagram should be displayed on it. The names of the geometric shapes transferred to the diagram must exactly repeat the information of the highest level. If two arrows are parallel with respect to the other's arcs (i.e., they start on the edge of one process and end both on one edge of the other process), then perhaps to optimize the model they should be combined and choose a suitable name, which is perfectly displayed in IDEF0 (examples of diagrams in Visio can be viewed).

An example of the implementation of the IDEF0 methodology on a specific model

You have already learned what an IDEF0 diagram is, you have partially seen examples and rules for constructing such diagrams. Now we should turn to practice. For a better understanding, the explanation will not be based on some "general" model, but on a specific example that will allow you to better and more fully understand the features of working with IDEF0 in the BPWin program.

As an example, the speed of the train from point A to point B. It should be taken into account that the train cannot develop more than the allowed speed. This line is established on the basis of operating experience and the influence of trains on the railway track. It should be understood that the purpose of the train is to deliver passengers, who, in turn, paid in order to safely and comfortably reach their destination. An IDEF0 diagram is helpful, examples of which can be found in this article.

The initial information is:

track line data;
passport of the entire distance;
path plan.

Control data:

Direction of the chief, head of the track service.
Information about the existing flow of movement of trains.
Information about the planned repairs, reconstruction and change of tracks.

The result of the model is:

Limiting the permissible speeds with an indication of the reason for the limitation.
Permissible speeds when driving at separate points and during the haul of trains.

When the context diagram is built, it needs to be detailed and then a composite diagram is created, which will be the first level diagram. It will show all the main functions of the system. The IDEF0 methodology and diagram for which the decomposition is done is called the parent. The IDEF0 decomposition is called a child decomposition.

Conclusion

After the decomposition at the first level, the decomposition of the second level is carried out - and so on until further decomposition loses its meaning. All this is done to obtain the most detailed graphical diagram of ongoing and planned processes. it ready example IDEF0 diagrams by which you can navigate right now.

Description of the business process diagrams "Accounting for computer equipment of the enterprise"

Description of IDEF0 diagram

To build a business process, an IDEF0 diagram was used. The IDEF0 methodology prescribes the construction of a hierarchical system of diagrams - single descriptions of system fragments. First, a description of the system as a whole and its interaction with the outside world is carried out (context diagram). Three levels of the diagram were built:

1. Contextual

2. Functional decomposition

Figure 1 - Context diagram "Accounting for enterprise computer equipment"

Figure 1 shows a context diagram of the business process "Accounting for enterprise computer equipment". It displays the system as a whole and its interaction with the main external flows of information.

Arrows are indicated in the context diagram.

Arrow types:

Input (input materials: computers and accessories)

Output (output is a report)

Control arrows are documents and managers

The arrows of the mechanisms are employees and equipment

Input information for processing:

Computers - PCs (personal computers) located in the enterprise

Components - materials required for upgrading computers (video cards, motherboards, processors, cases, power supplies, memory modules)

Output streams:

Report - a ready-made report on the accounting of computer equipment of the enterprise

Input controls:

Rules - conditions that must be met in order to achieve the goal.

Orders - the task assigned to the enterprise (to keep records of computer equipment at the enterprise using certain information systems)

Managers are directors and general managers of the enterprise.

Input Resources:

PC - computers with the help of which accounting is carried out.

Employees are specialists who carry out instructions assigned by management. After constructing a conceptual model, a functional decomposition was carried out - the system is divided into subsystems and each subsystem is described separately (decomposition diagrams).

Figure 2 shows a functional decomposition of four jobs.

Figure 2 - Functional decomposition "Accounting for enterprise computer equipment"

The following types of work were identified:

1) Registration of deliveries - the process in which the id is assigned to the product, sent to storage, to the warehouse and information about the product is entered into the program.

The work Registration of supplies includes seven boundary arrows (entrance, control, mechanism) and an internal arrow leaves (connection by entrance).

Arrow communication at the entrance between the works Registration of deliveries and Maintenance of the computer (computer);

Arrows of entry, exit, control are repeated in subsequent works.

2) Computer maintenance - the process in which the assembly, repair and modernization of computers takes place.

The Computer Maintenance work includes four boundary arrows (input, control, mechanism, output) and several internal arrows (input communication, input feedback).

Arrow control - rules, orders, leader;

Arrow connection at the entrance between the jobs Computer Maintenance and Placement (entering data into the database), between the jobs Computer Maintenance and Reporting (entering data into the database);

3) Placement - the process in which the placement of computers in offices (offices) takes place.

Arrows control - rules, orders, leader;

Arrow mechanism - employees;

Arrow link on input between Spreading and Reporting (assigning an id);

4) Drawing up a report - the final stage of the accounting process, which consists of summarizing totals obtained by performing the previous data of the current accounting.

Then each subsystem is broken down into smaller decompositions, and so on, until the desired degree of detail is achieved.

Figure 3 is a diagram showing the work of Procurement in more detail.

As a result of detailing, the main functions were highlighted. The section "Registration of supplies" includes seven main arrows (entry, exit, control, mechanism).

Arrow entry - computers and accessories;

Control arrows are rules, orders and a leader. Forking arrows;

Mechanism arrows, branching - PC, employees;

Arrows of entry, control, mechanisms are repeated in all works.

1) Assigning a number - assigning an individual number to computers and accessories.

Entry arrows - computers and accessories. Arrow computers are repeated in subsequent works, except for the compilation of the report;

Control arrows - rules, orders and leader;

Mechanism Arrows - PC and Employees;

Arrow link at the entrance between the works Assigning a number and Sending goods to a warehouse (transfer), between Assigning a number and Putting on balance (entering into the base);

2) Sending goods to the warehouse - sending the goods with the assigned number to the warehouse.

Exit Arrow - Computer;

Control arrows - rules, orders and leader.

Arrow link at the entrance between the works "Sending goods to the warehouse" and "Setting on the balance sheet" (quantity);

3) Balancing - entering information into a computer.

Control arrows - rules, orders and leader;

Mechanism Arrows - PC and Employees;

Figure 4 is a diagram detailing computer maintenance in more detail.

As a result of detailing, the main functions performed in the process of computer maintenance were highlighted.

The computer maintenance work includes 4 boundary arrows (input, output, control, mechanism). Internal arrows (input feedback, input communication).

1) Assembly of computers - configuration of computers for individual orders of managers.

Control arrows - rules, orders and leader;

Mechanism Arrows - Employees;

Arrow link at the entrance between the works: "Assembling computers" and "Repairing computers" (computer);

2) Computer repair - assembly of computers approved for improvement.

Exit arrow - entry into the base;

Control arrows - rules, orders and leader;

Mechanism Arrows - Employees;

Arrows of entry, exit, control, mechanism are branching;

Arrow link at the entrance between the works: "Computer repair" and "Upgrade" (accessories);

3) Upgrade - improvement, improvement, upgrade of the computer.

Exit arrow - entry into the base;

Control arrows - rules, orders and leader;

Mechanism Arrows - Employees;

Arrows of control, mechanism are branching;

Figure 5 shows the Reporting Chart in more detail. The work decomposition. Reporting includes 4 boundary arrows (input, output, control, mechanisms). Internal arrows (input feedback, input communication).

As a result of the work, the following functions were derived:

1) Data collection - collection of information for analysis and decision making.

Enter arrow - assigning id;

Control arrows - rules, orders and leader;

Arrows of entry, control, mechanism are branching;

Arrow link on the entrance between jobs: Data collection and Data validation (records);

2) Data verification - verification of information and sending it to the preparation of a report.

Exit arrow - Report;

Control arrows - rules, orders and leader;

Mechanism Arrows - Employees, PC;

Arrows of entry (assignment of id), control, mechanism are forking;

Input feedback arrow from “Data Check” to “Data Acquisition” (repeated check).

DFD diagram description

The Computer Maintenance work decomposition Figure 1 defines four internal activities, two external entities, and two data stores.

Figure 1 - Computer maintenance

1) Computer assembly - the process of assembling a computer from existing components.

2) Drawing up a report - a process that consists of summarizing the final indicators obtained by performing the work of the current accounting.

3) Diagnostics - performance check

4) Upgrade - improvement, improvement, upgrade of the computer.

External entities: computers and components

Data stores:

1) Warehouse - a place where assembled and upgraded computers are stored.

2) DB - a database that stores all reports and all information about the work done.

We collect information about the computer and select components for its assembly. Then we assemble the computer and send it to the warehouse for storage, but besides that, after assembling it, we can first send it for diagnostics, check for operability, and then only to the warehouse. After diagnosing the assembled computer, we send the data to compile a report on the work done and enter the information into the Database.

We also have another external entity, this is a computer. We send it for modernization, after which it is for diagnostics to check its operability, then we draw up a report and enter information about the work done in the Database. Or, after the modernization, we send the goods to the warehouse, and then we carry out diagnostics, draw up a report and enter the information into the Database.

The work decomposition "Reporting" Figure 2 defines three internal activities, three external entities, and two data stores.

1) Data collection - collection of information about computers and components.

2) Validation - checking the data for accuracy.

3) Report - writing a report on the work done.

External entities: components, computers, manager.

Data warehouse - Data about computers and components, report data.

Collecting information about computers and accessories, then sending them for storage. After that, we check the data for accuracy, draw up a report and send it back for storage to the first data warehouse (Figure 2), or send the report data to the second data warehouse (Figure 2) and then send it to the head for verification.

The manager checks, makes notes, corrections and sends for re-checking. After that, the report is sent for storage until the manager is re-checked.

Description of IDEF3 diagram

In the work decomposition Computer maintenance (Fig. 1), several intersections are defined that connect one or several jobs, several internal jobs.

1) Repair - assembling the computer with prefabricated components

2) Assembly - bringing the computer back to normal

3) Upgrade - computer upgrade

4) Computers - a product after assembly and modernization

5) Send to warehouse - send to storage after improvement (assembly)

6) Diagnostics - performance check.

7) Report - information about the work done.

Intersections - Connectors:

1) J2 - all actions start at the same time.

2) J6 - Confluence Junction. A node that collects many arrows into one, indicating the need for the condition of completing the work-sources of arrows to continue the process.

3) J7 - it is shown that these conditions cannot be simultaneously fulfilled.

4) J9 - these actions end at the same time after which a report on the work done is drawn up.

The IDEF3 diagram shows that the J2 junction has two branching arrows for work (build and upgrade) that start at the same time. Only after these works are completed, the finished product (computer) comes out, connects the J6 intersection. After that, there is a connection at the intersection J7, which shows that two works (sending goods to the warehouse and diagnostics) cannot be performed simultaneously. After completing the previous work, the process of drawing up a report on the work is underway, which is connected by the junction J9.

Open the project in which you want to create the model. If you have not created any projects yet, you can use the DEMO project, which is available immediately after installing Cradle, or create your own project.

To enter the DEMO project use Username — MANAGER, password - MANAGER

How to create your project is shown in detail in this video.

After creating a new project, you can also use to login Username — MANAGER and password - MANAGER

Model creation

In order to create the IDEF0 model include Project panel and go to the modeling section Essential Domain

Note : Similarly, you can create models in the Implementation Domain section of the modeling, as well as in any section configured by the user. The modeling section is actually a namespace within which streams can be reused.

To create the IDEF0 context model, right-click on the IDEF0 section and select the menu items New-> Element

Please note that this is the name of the entire model as a whole, not a function block on A0.

After that, the drawing area will open and you can start creating the context model.

Function block creation

To do this, select the function block symbol on the palette

and click once on the work area where you want to create the function block.

A dialog box will appear in which you must enter the name of the function block, and then click OK.

As a result, a function block with the name you specified will be created.

You can select the border of the block and change its scale

Creating streams

To create streams, select a stream symbol from the palette (no tunneling or tunneling)

then click on the side of the function block from which you want to create a flow and click on any area of the function block

then a dialog box will appear for entering the name of the stream. Enter short title stream and click OK

Note: You will be able to enter a detailed description of the stream later in its specification.

After that, by analogy, you can create all the necessary streams

Save the model by clicking the floppy button or CTRL + S. When you save, symbol specifications are generated that you can edit to provide a more detailed description of the model elements.

After saving the model, you will be able to see the created specifications in the project panel in the same section where you created the model. Two types of specifications will be generated - Function and Flow.

Decomposition of the model

in the dialog that appears, leave the default settings and click OK

After that, a child diagram A1 will be created and all flows from diagram A0 will be transferred to it.

Now you can rename the created function block template (with a question instead of a name) and create additional ones, in the same way as we created them earlier.

To rename a function block preset, select it and select Rename from the context menu

and enter the required name

By analogy, create other function blocks corresponding to this level of decomposition.

To create flows between these functional blocks, you must first click on the source, then on the intermediate point to create a bend and then on the sink, for example, like this:

The result is a flow with two bends.

You can correct the position of the bends by selecting the flow and dragging the bend points to the desired location

Watch the video clip in order to see it in dynamics

To remove (or add) an inflection point, press the SHIFT key on your keyboard and click on the point you want to remove or in the flow where you want to create it.

Save the diagram and verify that the appropriate specifications have been generated

By analogy, you can decompose the A1 functional blocks.