When creating information models, prior to the choice of SOI, it is necessary to be guided by the following ergonomic requirements:
♦ in terms of the amount of information, they must ensure an optimal information balance and not lead to such undesirable phenomena as a deficit or excess of information;
♦ in form and composition, they must correspond to the tasks of the labor process and the capabilities of a person to receive, analyze, evaluate information and implement control actions.
Taking these requirements into account in the process of designing information models allows the operator to perform the functions assigned to him with the necessary efficiency and accuracy, prevents the occurrence of erroneous actions, and ensures the effective functioning of the "man-machine" system.
Experience in the development and use of information models, as well as the analysis of operators' activities with them, make it possible to formulate a number of the most important characteristics of information models.
Display of essential information and problem situation. In the information model, only the basic properties, relationships, connections of managed objects should be presented. In this sense, the model reproduces reality in a simplified form and is always some of its schematization. The degree and nature of simplification and schematization can be determined on the basis of an analysis of the tasks of the "man-machine" systems.
When a problematic situation arises in management, its perception is facilitated if the information model provides for the display:
♦ changes in the properties of the elements of the situation that occur during their interaction. In this case, change
the properties of individual elements are perceived not in isolation, but in the context of the situation as a whole;
♦ dynamic relations of controlled objects, while the links and interactions of the information model should be displayed in development. It is permissible and even useful to exaggerate or enhance the display of trends in the development of elements of a situation, their connections or the situation as a whole;
♦ conflict relations, into which the elements of the situation enter.
Organization of the structure and visibility of information models. The optimal organization of the structure of the information model allows you to quickly and accurately perceive the displayed situation as a whole. One way to organize it this way is to have a good layout. The information model should represent a set of information that is in a definite and obvious interaction.
The model must be descriptive, i.e. to provide the operator with the ability to quickly, accurately and without painstaking analysis to perceive the data. However, control objects, their properties and interactions do not always have visual signs. In this case, when developing information models, one has to solve problems close to those that are defined in the methodology of science as "visualization of concepts".
Stages of building an information model. The order of building an information model, as a rule, is as follows:
1) determination of system tasks and the priority of their solution;
2) determining the sources of information, methods for solving problems, the time required to solve them, as well as the required accuracy;
3) compiling a list of types of control objects, determining their number and parameters of the system;
4) compilation of a list of attributes of different types of control objects;
5) the distribution of objects and features according to the degree of importance, the choice of critical objects and features, the consideration of which is necessary in the first place;
6) the choice of the system and methods of coding control objects, their states and characteristics;
7) development of a general composition of information models;
8) determination of the list of executive actions of operators, carried out in the process of solving the problem and after making a decision;
9) creation of a model that simulates a possible situation, checking the effectiveness of the selected options for information models and information coding systems. The criterion for efficiency is the time, accuracy and intensity of the operator's work;
10) determination of changes based on the results of experiments with the composition of information models and coding systems, checking the effectiveness of each new version on the model;
1 1) determination of the level of professional training of operators on the model and its compliance with the given one;
12) drawing up instructions for the work of operators in the control system.
The proposed procedure for constructing information models is outlined only in general terms. It can vary depending on the specifics of certain control systems and operator functions.
Presentation:2. What is a model? When is modeling used? A model is a new object that reflects the features of the object, process or phenomenon that are essential from the point of view of the goal of modeling.
Modeling is used in cases where the object is too large or too small, the process proceeds very quickly or very slowly, the study of the object can be dangerous for others, and so on.3. Confirm by examples the validity of the following statements:
a) several models can correspond to one object;
b) one model can correspond to several objects.
Examples: a - Object: Car, models: parking space, drawing, road sign, radio-controlled car.
b - Model: Scheme, objects: metro scheme, building scheme, radio schemes
4. Give examples of full-scale and information models.
Full-scale models: a toy, a mannequin, a photograph, etc.Information models: table, graph, formula, etc.
5. In the following list of models, indicate those that can be used for:
a - layout of the residential area development; photographs of the movement of air masses.b - photographs of the movement of air masses; a model of a flight of an aircraft of a new design in a wind tunnel; diagram of the structure of human internal organs.
c - photographs of the movement of air masses; a model of a flight of an aircraft of a new design in a wind tunnel; diagram of the structure of human internal organs.
d - photographs of the movement of air masses; train timetable; flight model of an aircraft of a new design in a wind tunnel.
e - train timetable.
6. Give an example of an information model
a - a guy, height 173 cm, brown eyes, brunette.b - a tall guy, fair-haired, athletic, dexterous, fast.
c - kind, fluffy, constantly meows.
d - 3rd floor, spacious 3-room apartment.
d - hard cover
f - CD-R disc with a capacity of 700 MB, rock music is recorded.
g - Russian city, multinational, located in the Nizhny Novgorod region.
7. Describe the stages of building an information model. What is the essence of the formalization stage?
Building an information model begins with analyzing the condition of the problem. After the analysis, the object and the purpose of the simulation are determined. After that, the essential features of the model are highlighted and, at the end, formalization.Formalization is the replacement of a real object with its formal description, that is, its information model.
8. List the types of information models depending on the form of presentation of information about the object of modeling. Give examples of information models of each type.
Scheme - metro map, road map, etc.Table - cool magazine, product price list, etc.
The hierarchical model is the classification of animal species, the location of books in the library, etc.
At this stage, the properties, states, actions and other characteristics of elementary objects are clarified in any form: orally, in the form of diagrams, tables. An idea is formed about the elementary objects that make up the original object, that is, the information model.
Models should reflect the most essential features, properties, states and relationships of objects of the objective world. They provide complete information about the object. It can be versatile and quite extensive.
There doesn't have to be a lot of information. It is important that it be "on the merits of the issue", that is, correspond to the purpose for which it is used.
In order to study an object, a person collects information about it. Depending on the purpose for which he is being investigated, what means and knowledge a person possesses, information of different volume will be obtained. One and the same object can be viewed from different points of view and, accordingly, described in different ways. Some properties of an object can be written in the form of formulas linking various parameters. For example, the law of conservation of mass in chemical reactions or the laws of refraction of light, etc. To describe objects, their properties and relationships, you can use various schemes, drawings, sign systems, numerical characteristics. And although information cannot replace a real object, each such description will characterize it with varying degrees of accuracy.
In the information model, the parameters of the object and its components are presented in numerical, textual or other form, and actions during the study are presented in the form of information processing processes.
Information models play a very important role in human life.
The knowledge you receive at the institute has the form of an information model designed for the purpose of studying objects and phenomena.
The information model never fully characterizes the object, and it should not do this. Different information models can be built for the same object.
Let's choose an object such as a "person" for modeling. A person can be viewed from various points of view: as a separate individual and as a person in general.
If you have a specific person in mind, then you can build models that are presented in table. 2.1-2.3.
Table 2.1. Cadet information model
Table 2.2. Information model of the visitor honey. cabinet
Table 2.3. Information model of an employee of an enterprise
If we consider a person as a biological species, then it is possible to build information models describing the structure or functioning of various systems of the body, for example, the nervous system or the circulatory system.
Let's consider other examples of different information models for the same object.
Numerous witnesses to the crime reported a variety of information about the alleged attacker - these are their information models. The police representative should choose from the stream of information the most essential, which will help to find the offender and detain him. A representative of the law may have more than one informational model of a bandit. The success of the case depends on how correctly the essential features are chosen and the secondary ones are discarded.
Selection of the most essential information for creatinginformation model and its complexity are due to the purpose of modeling.
Building the information model is the starting point for the model development phase.
All the input parameters of the objects, selected during the analysis, are arranged in decreasing order of importance and the model is simplified in accordance with the purpose of modeling. This discards factors that are insignificant from the point of view of the one who determines the model. If we discard the most significant factors, then the model will turn out to be incorrect.
Several models can be built depending on the number of determining factors. Many studies use the technique of creating models for one object, starting with the simplest ones - with a minimum set of defining parameters. Further, the models become more complex, that is, those parameters are introduced that were previously discarded.
Sometimes the task can initially be formulated in a simplified form. It clearly sets goals and defines the parameters of the model that must be taken into account.
All elementary objects, selected during the analysis, must be shown in relationship. In the information model, only undeniable relationships and obvious actions are displayed. Such a model provides the primary idea that determines the further course of the simulation.
Iconic model
The information model, as a rule, is presented in one or another symbolic form, which can be either computer or non-computer. Before taking up computer modeling, a person makes preliminary sketches of drawings or diagrams on paper, displays calculation formulas. The process of creativity and research always involves a painful search and a basket of discarded drafts. And only for simple, familiar tasks, non-computer sign models are not needed. Today, when the computer has become the main tool of the researcher, many prefer preliminary sketches, formulas immediately compose and write on it.
Computer model
Now that the informational sign model has been formed, one can proceed to the actual computer modeling - the creation of a computer model. The question immediately arises about the means that are necessary for this, that is, about instruments modeling .
There are countless software packages that allow research (modeling) information models. Each software environment has its own tools and allows you to work with certain types of information objects. Therefore, the researcher faces the difficult question of choosing the most convenient and effective environment for solving the problem.
Some software environments are used by humans as an effective aid for the implementation of their own ideas. In other words, a person already knows what the model will be and uses a computer to give it a symbolic form. For example, graphical environments are used to build geometric models, diagrams, and a text editor environment for verbal or tabular descriptions.
Other software environments are used as a means of processing initial information and obtaining and analyzing results. Here the computer acts as an intelligent assistant. This is how large amounts of information are processed in a database environment or calculations are performed in spreadsheets.
In the process of developing a computer model, the initial informational sign model will undergo some changes in the form of representation, since it should be oriented towards a specific software environment and tools.
For example, if you are exploring a geometric model consisting of elementary graphic objects, the graphical editor environment is convenient for modeling. However, for the development of geometric models in some cases, you may need a programming environment with graphical means.
For verbal models, word processors are used with ample opportunities for the design of the output document - a formula editor, built-in business graphics, table elements.
There are various programs that allow you to include block diagrams of algorithms, electronic circuits, diagrams, etc. in the description.
Information models, where not only information about objects is displayed, but also their relationships are indicated, are implemented in database management systems.
If you are exploring a mathematical model, then neither a graphics editor environment, nor a database environment, nor a word processor environment is suitable for you. An effective tool for researching mathematical models is a programming environment where a computer model is presented in the form of a program. Another powerful tool for exploring such patterns is the spreadsheet environment. Here the original informational sign model is presented in the form of a table linking elementary objects according to the rules for constructing links in this environment.
Computer model - a model implemented by means of a software environment.
Based on the foregoing, we can conclude that when modeling on a computer, it is necessary to have an idea of the classes of software tools, their purpose, tools and technological methods of work.
Rules for building information models.
Information model there is a set of information organized according to certain rules about the state and functioning of the control object and the external environment. For the operator, it is a kind of simulator of the properties of real objects that are essential for control, i.e. the source of information on the basis of which he forms an image of the real situation, analyzes and evaluates the current situation, plans control actions, makes decisions that ensure the effective operation of the system, and also evaluates the results of their implementation. In other words, the operator deals not with the object as such, but with its symbolic representation. In any kind of work with information, we are always talking about its representation in the form of certain symbolic structures. Formation of information presentation is its coding.
Conceptual model is a set of operator's ideas about work tasks, the state and functioning of the working system and his own methods of control actions on them. The images and representations that make up the content of the conceptual model are not only a reflection of reality. They play the role of generalized schemes of activity, formed in the process of learning and training. The conceptual model is characterized by enormous information redundancy, but at one time or another, only images and schemes of activity associated with the directly solved problem are actualized and realized. When creating information models, it is necessary to be guided by the following ergonomic requirements:
♦ in terms of content, information models should adequately reflect management objects, the external environment and the state of the management system itself;
♦ in terms of the amount of information, they must ensure an optimal information balance and not lead to such undesirable phenomena as a deficit or excess of information;
♦ in form and composition, they must correspond to the tasks of the labor process and the capabilities of a person to receive, analyze, evaluate information and implement control actions.
Taking these requirements into account in the process of designing information models allows the operator to perform the functions assigned to him with the necessary speed and accuracy, prevents the occurrence of erroneous actions, and ensures the effective functioning of the "man-machine" system. Experience in the development and use of information models, as well as the analysis of operators' activities with them, make it possible to formulate a number of the most important characteristics of information models.
Display of essential information and problem situation. In the information model, only the basic properties, relationships, connections of managed objects should be presented. In this sense, the model reproduces reality in a simplified form and is always some of its schematization. The degree and nature of simplification and schematization can be determined on the basis of an analysis of the tasks of the "man-machine" systems. When a problematic situation arises in management, its perception is facilitated if the information model provides for the display:
♦ changes in the properties of the elements of the situation that occur during their interaction. In this case, treason
the properties of individual elements are perceived not in isolation, but in the context of the situation as a whole;
♦ dynamic relations of controlled objects, while the links and interactions of the information model should be displayed in development. It is permissible and even useful to exaggerate or enhance the display of trends in the development of elements of a situation, their connections or the situation as a whole;
♦ conflict relations, into which the elements of the situation enter.
- Stages of building an information model.
The order of building an information model, as a rule, is as follows:
1) determination of system tasks and the priority of their solution;
2) determining the sources of information, methods for solving problems, the time required to solve them, as well as the required accuracy;
3) compiling a list of types of control objects, determining their number and parameters of the system;
4) compilation of a list of attributes of different types of control objects;
5) the distribution of objects and features according to the degree of importance, the choice of critical objects and features, the consideration of which is necessary in the first place;
6) the choice of the system and methods of coding control objects, their states and characteristics;
7) development of a general composition of information models;
8) determination of the list of executive actions of operators, carried out in the process of solving the problem and after making a decision;
9) creation of a model that simulates a possible situation, checking the effectiveness of the selected options for information models and information coding systems. The criterion for efficiency is the time, accuracy and intensity of the operator's work;
10) determination of changes based on the results of experiments with the composition of information models and coding systems, checking the effectiveness of each new version on the model;
11) determination of the level of professional training of operators on the model and its compliance with the given one;
12) drawing up instructions for the work of operators in the control system.
The proposed procedure for constructing information models is outlined only in general terms. It can vary depending on the specifics of certain control systems and operator functions.
Practical work No. 14
Completed by a student of group number ___________ Full name ______________________
Topic Designing programs based on the development of algorithms for processes of various nature.
Target: get familiar with the concepts of modeling and modeling, learn how to create computer models.
Theoretical information
Model - itan artificially created object that replaces some object of the real world (object of modeling) and reproduces a limited number of its properties. The concept of a model refers to fundamental general scientific concepts, and modeling is a method of cognizing reality used by various sciences.
The object of modeling is a broad concept that includes objects of animate or inanimate nature, processes and phenomena of reality. The model itself can be either a physical or an ideal object. The former are called full-scale models, the latter are called information models. For example, a building model is a full-scale model of a building, and a drawing of the same building is its information model presented in graphic form (graphic model).
In experimental scientific research, full-scale models are used that allow one to study the patterns of the phenomenon or process under study. For example, in a wind tunnel, the flight process of an aircraft is simulated by blowing a model of an aircraft with an air stream. This determines, for example, the loads on the aircraft body that will take place in a real flight.
Information models are used in theoretical studies of modeling objects. Nowadays, the main tool for information modeling is computer technology and information technology.
Computer modelling includes the progress of the realism of the information model on a computer and the study with the help of this model of the object of modeling - a computational experiment.
Formalization
The subject area of computer science includes tools and methods of computer modeling. A computer model can only be created on the basis of a well-formalized information model. What is formalization?
Formalization of information about some object is its reflection in a certainform. You can also say this: formalization is the reduction of content to form. Formulas describing physical processes are the formalization of these processes. The radio circuit of an electronic device is a formalization of the functioning of this device. The notes written on a sheet of music are the formalization of music, etc.
A formalized information model is a certain set of signs (symbols) that exist separately from the modeling object and can be transmitted and processed. Implementation of an information model on a computer comes down to its formalization into data formats that a computer can "handle" with.
But we can talk about the other side of formalization as applied to a computer. A program in a certain programming language is a formalized representation of the data processing process. This does not contradict the above definition of a formalized information model as a set of signs, since a machine program has a sign representation. A computer program is a model of human activity in information processing, reduced to a sequence of elementary operations that a computer processor can perform. Therefore, computer programming is the formalization of the information processing process. And the computer acts as the formal executor of the program.
Information Modeling Stages
Building an information model starts with system analysis object of modeling (see. "System Analysis"). Imagine a fast-growing firm whose management is faced with the problem of decreasing the efficiency of the firm as it grows (which is a common situation) and decided to streamline management activities.
The first thing that needs to be done on this path is to conduct a systematic analysis of the firm's activities. A systems analyst invited to a firm should study its activities, identify the participants in the management process and their business relationships, i.e. the modeling object is analyzed as a system. The results of such an analysis are formalized: they are presented in the form of tables, graphs, formulas, equations, inequalities, etc. theoretical model of the system.
The next stage of formalization - the theoretical model is translated into the format of computer data and programs. For this, "either ready-made software is used, or programmers are involved to develop it. In the end, it turns out computer information model, which will be used for its intended purpose.
For an example with a firm, using a computer model, the optimal management option can be found, in which the highest efficiency of the firm will be achieved according to the criterion laid down in the model (for example, obtaining the maximum profit per unit of investment).
Classification of information models can be based on different principles. If we classify them according to the dominant technology in the modeling process, then we can distinguish mathematical models, graphic models, simulation models, tabular models, statistical models, etc. (biological) systems and processes, models of processes of optimal economic planning, models of educational activities, models of knowledge, etc. Classification issues are important for science, because they allow you to form a systematic view of the problem, but their importance should not be overestimated. Different approaches to classifying models can be equally useful. In addition, a specific model can by no means always be attributed to one class, even if we limit ourselves to the above list.
Let us dwell on this classification in more detail and explain it with examples.
By simulating the motion of a comet that invaded the solar system, we describe the situation (predict the trajectory of the comet's flight, the distance at which it will pass from the Earth, etc.), i.e. set purely descriptive goals. We do not have any possibilities to influence the motion of the comet, to change something during the modeling process.
In optimization models, we can influence processes, trying to achieve some goal. In this case, the model includes one or several parameters available to our influence. For example, changing the thermal regime in a granary, we can strive to choose one in order to achieve maximum grain safety, that is, we optimize the process.
It is often necessary to optimize the process by several parameters at once, and the goals can be very contradictory. For example, knowing the prices of food and a person's need for food, organize meals for large groups of people (in the army, summer camp, etc.) as useful as possible and as cheaply as possible. It is clear that these goals, generally speaking, do not coincide at all, i.e. when modeling, there will be several criteria between which a balance must be sought. In this case, one speaks of multicriteria models.
Game models can be related not only to children's games (including computer games), but also to very serious things. For example, a commander, before a battle, in the presence of incomplete information about the opposing army, must develop a plan in what order to bring certain units into battle, etc., taking into account the possible reaction of the enemy. In modern mathematics, there is a special section - game theory, which studies decision-making methods in conditions of incomplete information.
Finally, it happens that the model largely imitates the real process, i.e. imitates it. For example, modeling the dynamics of the number of microorganisms in a colony, one can consider a set of individual objects and monitor the fate of each of them, setting certain conditions for its survival, reproduction, etc. In this case, sometimes an explicit mathematical description of the process is not used, being replaced by some verbal conditions (for example, after a certain period of time, the microorganism is divided into two parts, and the other segment dies). Another example is modeling the motion of molecules in a gas, when each molecule is represented in the form of a ball, and the conditions for the behavior of these balls when they collide with each other and with walls are set (for example, an absolutely elastic impact); you do not need to use any equations of motion.
We can say that most often simulation modeling is used in an attempt to describe the properties of a large system, provided that the behavior of its constituent objects is very simple and clearly formulated. The mathematical description is then made at the level of statistical processing of the simulation results while finding the macroscopic characteristics of the system. Such a computer experiment actually pretends to reproduce a natural experiment. To the question "why do this?" the following answer can be given: imitation modeling allows us to single out "in a pure form" the consequences of the hypotheses inherent in our ideas about microevents, clearing them from the influence of other factors inevitable in a natural experiment, which we may not even be aware of. If such modeling also includes elements of a mathematical description of events at the micro level, and if the researcher does not set the task of finding a strategy for regulating the results (for example, managing the number of microorganisms colony), then the difference between the simulation model and the descriptive one is rather arbitrary; it is rather a question of terminology.
Another approach to the classification of mathematical models subdivides them into deterministic and stochastic (probabilistic) ones. In deterministic models, the input parameters are measurable unambiguously and with any degree of accuracy, i.e. are deterministic values. Accordingly, the process of evolution of such a system is deterministic. In stochastic models, the values of the input parameters are known only with a certain degree of probability, i.e. these parameters are stochastic; accordingly, the process of evolution of the system will also be random. At the same time, the output parameters of the stochastic model can be both probabilistic values and uniquely determined ones.
