receives by means of: 1) special devices; 2) organs of touch; 3) hearing organs; 4) thermometer. 3. An example text information can serve as: 1) multiplication table on the cover of a school notebook; 2) illustration in the book; 3) the rule in the native language textbook; 4) photography; 4. Translation of text from of English language in Russian it can be called: 1) the process of storing information; 2) the process of obtaining information; 3) the process of protecting information; 4) the process of information processing. 5. Exchange of information is: 1) doing homework; 2) watching a TV program; 3) observation of the behavior of fish in the aquarium; 4) talking on the phone. 6. The number system is: 1) a sign system in which numbers are written according to certain rules using symbols (numbers) of a certain alphabet; 2) an arbitrary sequence of numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9; 3) the sequence of digits 0, 1 is infinite; 4) the set of natural numbers and signs arithmetic operations... 7. Binary number 100012 corresponds to decimal: 1) 1110 2) 1710 3) 25610 4) 100110 8. The number 2410 corresponds to the number: 1) 1816 2) ВF16 3) 2016 4) 1011016 9. The unit of information amount is taken: 1) 1 byte; 2) 1 bit; 3) 1 baud; 4) 1 cm. 10. Which of the devices is intended for inputting information: 1) processor; 2) printer; 3) keyboard; 4) monitor. eleven. Computer viruses: 1) arise due to failures in the hardware of the computer; 2) are of biological origin; 3) are created by people specifically to damage the PC; 4) are the result of errors in operating system... 12. An algorithm is: 1) the rules for performing certain actions; 2) a set of commands for the computer; 3) protocol for computer network; 4) a description of the sequence of actions, the strict execution of which leads to the solution of the problem in a finite number of steps. 13. The property of the algorithm, which is the absence of errors, the algorithm must lead to the correct result for all admissible input values is called: 1) effectiveness; 2) mass character; 3) discreteness; 4) limb. 14. The property of an algorithm that the same algorithm can be used with different input data is called: 1) efficiency; 2) mass character; 3) limb; 4) determinism. 15. Text editor - a program designed for: 1) creating, editing and formatting text information; 2) working with images in the process of creation game programs; 3) management of PC resources when creating documents; 4) automatic translation from symbolic languages ​​into machine codes. 16. The main functions of a text editor include: 1) copying, moving, destroying and sorting text fragments; 2) creation, editing, saving and printing of texts; 3) strict adherence to spelling; 4) automatic processing of information presented in text files. 17. A cursor is: 1) a text input device; 2) a key on the keyboard; 3) the smallest display element on the screen; 4) a mark on the monitor screen indicating the position at which the text entered from the keyboard will be displayed. 18. Text formatting is: 1) the process of making changes to the existing text; 2) the procedure for saving text on disk in the form text file; 3) the process of transmitting text information on computer network; 4) a procedure for reading a previously created text from an external storage device. 19. Text typed in text editor, is stored on an external storage device: 1) as a file; 2) encoding tables; 3) catalog; 4) directories. 20. One of the main functions of the graphic editor is: 1) image input; 2) storage of the image code; 3) creating images; 4) viewing the output of the contents of the video memory. 21. An elementary object used in raster graphic editor, is: 1) screen point (pixel); 2) rectangle; 3) circle; 4) a palette of colors. 22. A spreadsheet is: 1) application program designed for processing data structured in the form of a table; 2) an application program for image processing; 3) a PC device that manages its resources in the process of processing data in tabular form; 4) system program, which manages PC resources when processing tables. 23. A spreadsheet is: 1) a set of numbered lines and columns named by letters of the Latin alphabet; 2) a set of rows and columns named by letters of the Latin alphabet; 3) a set of numbered rows and columns; 4) a set of rows and columns, named by the user in an arbitrary way. 24. Select the correct formula entry for spreadsheet: 1) C3 + 4 * E 2) C3 = C1 + 2 * C2 3) A5B5 + 23 4) = A2 * A3-A4

Information concept

Into the concept "information"(from lat. informatio- information, explanations, presentation) different meanings are put in according to the industry where this concept is considered: in science, technology, ordinary life, etc. Usually, information is understood as any data or information that interests anyone (reporting about any events, about someone's activities, etc.).

In the literature, you can find a large number of definitions of the term "information" that reflect different approaches to its interpretation:

Definition 1

• Information- information (messages, data), regardless of the form of their presentation ("Federal Law of the Russian Federation from $ 27.07.2006, No. $ 149 $ -FZ On Information, Information Technologies and Information Protection");
• Information- information about the surrounding world and the processes occurring in it, perceived by a person or a special device (Explanatory Dictionary of the Russian Language Ozhegov).

Speaking about computer data processing, information is understood as a certain sequence of symbols or signs (letters, numbers, encoded graphics and sounds, etc.), which carries a semantic load and is presented in a form understandable for a computer.

In computer science, the following definition of this term is most often used:

Definition 2

Information- this is conscious information (knowledge expressed in signals, messages, news, notifications, etc.) about the surrounding world, which are the object of storage, transformation, transmission and use.

Same Announcement(an article in a magazine, an advertisement, a story, a letter, a reference, a photograph, a TV show, etc.) can carry a different amount and content of information for different people, depending on their accumulated knowledge, on the level of accessibility of this message and on the level of interest in it ... For example, a news item written in Chinese does not convey any information to a person who does not know this language, but may be useful for a person who knows Chinese. News presented in a familiar language will not contain any new information if its content is not clear or is already known.

Information is considered as a characteristic not of the message, but the relationship between the message and its recipient.

Types of information

Information can exist in various types:

• text, pictures, drawings, photographs;
• light or sound signals;
• radio waves;
• electrical and nerve impulses;
• magnetic records;
• gestures and facial expressions;
• smells and taste;
• chromosomes through which the traits and properties of organisms are inherited, etc.

Distinguish main types of information, which are classified according to its form of presentation, methods of encoding and storing it:

• graphic- one of the oldest species, with the help of which information about the surrounding world was stored in the form of rock paintings, and then in the form of paintings, photographs, diagrams, drawings on various materials (paper, canvas, marble, etc.), which depict pictures of the real world;
• sound(acoustic) - for storage audio information in $ 1877, a sound recording device was invented, and for musical information, a method of encoding was developed using special characters, which makes it possible to store it as graphical information;
• text- encodes a person's speech using special characters - letters (different for each nation); paper is used for storage (notes in notebooks, book printing, etc.);
• numeric- encodes the quantitative measure of objects and their properties in the surrounding world using special characters - numbers (for each coding system its own); became especially important with the development of trade, economy and monetary exchange;
• video information- a way of storing "living" pictures of the surrounding world, which appeared with the invention of cinema.

There are also kinds of information for which methods of encoding and storage have not yet been invented - tactile information, organoleptic and etc.

Initially, information was transmitted over long distances using coded light signals, after the invention of electricity - the transmission of a signal encoded in a certain way over wires, later - using radio waves.

Remark 1

The founder of general information theory is considered Claude Shannon, who also laid the foundation for digital communication, writing the book "Mathematical Theory of Communication" in $ 1948, in which he was the first to substantiate the possibility of using binary code to transfer information.

The first computers were the means for processing numerical information. With the development of computer technology, PCs began to be used for storing, processing, transferring various types of information (text, numerical, graphic, audio and video information).

You can store information using a PC on magnetic disks or tapes, laser disks (CDs and DVDs), special non-volatile memory devices (flash memory, etc.). These methods are constantly being improved, and information carriers are also invented. All actions with information are performed by the central processor of the PC.

Objects, processes, phenomena of the material or non-material world, if viewed from the point of view of their information properties, are called information objects.

A huge number of different information processes can be performed on information, including:

• creation;
• reception;
• combination;
• storage;
• broadcast;
• copying;
• treatment;
• Search;
• perception;
• formalization;
• division into parts;
• measurement;
• usage;
• Spread;
• simplification;
• destruction;
• memorization;
• transformation;

Information properties

Information, like any object, has properties, the most important of which, from the point of view of informatics, are:

• Objectivity. Objective information - existing independently of human consciousness, methods of fixing it, someone's opinion or attitude.
• Credibility. Information reflecting the true state of affairs is reliable. Inaccurate information most often leads to misunderstandings or wrong decisions. The obsolescence of information can make it unreliable from reliable information, because it will no longer be a reflection of the true state of affairs.
• Completeness. Information is complete if it is sufficient for understanding and making decisions. Incomplete or redundant information can lead to a delay in decision making or an error.
• Accuracy of information - the degree of its proximity to the real state of an object, process, phenomenon, etc.
• The value of information depends on its importance for decision-making, problem solving and further applicability in any types of human activity.
• Relevance. Only the timely receipt of information can lead to the expected result.
• Comprehensibility. If valuable and timely information is incomprehensible, it will most likely become useless. Information will be understandable when it is at least expressed in a language that is understandable for the recipient.
• Availability. The information should correspond to the level of perception of the recipient. For example, the same questions are presented in different ways in school and university textbooks.
• Brevity. Information is perceived much better if it is presented not in detail and wordy, but with an acceptable degree of conciseness, without unnecessary details. Brevity of information is indispensable in reference books, encyclopedias, instructions. Consistency, compactness, convenient form of presentation facilitates understanding and assimilation of information.

Information concept

The word "information" comes from the Latin word informatio , which in translation means mixing, clarification, familiarization.

The concept of "information" in the course of computer science is basic (basic), it cannot be given through other, simpler concepts. In geometry, for example, the basic concepts are: “point”, “ray”, “plane”. Content basic concepts in any science is explained by examples or revealed by comparison with the content of other concepts.

Information - this is information about the world around that increases the level of human awareness.

For comparison, we also present some other definitions and characteristics:

• Information - the content of a message or signal; information considered in the process of their transmission or perception, allowing to expand knowledge about the object of interest.
• Information is one of the fundamental essences of the world around us.
• Information is a reflected diversity, that is, a violation of uniformity.
• Information is one of the main universal properties of matter.
• In the household In the sense of information, we mean the information that a person receives from the surrounding nature and society with the help of the senses, which increase his level of awareness.
• In science, information is understood as new acquired knowledge. For example, a mathematician will include in this concept the information that a person did not receive, but he himself created with the help of inferences.
• In cybernetics the concept of information is associated with control processes in complex systems,that part of knowledge that is used for orientation, active action, management, in order to preserve, develop the system;
• In philosophical sense is interaction, reflection, cognition.
• In a probabilistic sense - this is information that completely removes or reduces the existing uncertainty before it is received.
• In computer science, information- this is information about objects and phenomena of the environment, their parameters, properties and condition, which reduce the existing degree of uncertainty and incompleteness about them.
• In technology information is understood as messages transmitted in the form of signs or signals.

Types of information

By way of perceptioninformation is divided into the following types:visual, auditory, gustatory, olfactory and tactile... This division is based on the senses through which information is perceived by a person: sight, hearing, taste, smell and touch, respectively. Scientific studies show that over 90% of the information received by a person from the outside world is related to sight and hearing, about 10% - to taste, smell and touch. The world of wildlife gives a great many examples when the senses (organs for receiving information) have reached amazing perfection: the vigilance of the eagle's eye, the circular field of view of a dragonfly, the subtlety of smell and hearing of wild animals. Found in animals and senses that humans do not have. This is a lateral line in fish, an ultrasonic "locator" in bats. The salamander has a gland under the skin on its head that is able to distinguish sunlight ("third eye"). And the snake has an area of ​​skin between the eyes and nose that is very sensitive to heat. With the help of this organ, the snake perceives the thermal picture of the world.

A person creates devices that allow him to receive information that is inaccessible to him in direct sensations. Microscopes, telescopes, thermometers, speedometers - the list goes on and on. The analogs of the human sense organs in technical devices correspond to various sensors ... Getting information is called by entering ... IN personal computer special input devices are responsible for entering information: keyboard, scanner, digitizer, microphone, mouse and much more.

A person perceives information with the help of the senses. Perceived information comes in the form of energy signals (light, sound, heat) and radiation (taste and smell), and the process of receipt of these signals occurs continuously.

Sensitive organs of a living organism are mainly in nature discrete ... Visual images are perceived by the cells of the retina, tactile sensations arise in sensitive neurons, smells are perceived by the olfactory receptors, each of which is either in an excited or unexcited state at any given time. All sensory perceptions are transformed in the body from a discrete form into a continuous one, and the information is stored not in individual neurons of the brain, but is distributed throughout it as a whole. Continuity of presentation, for example, of visual information allows a person to confidently perceive the dynamics of the world around him. Discrete values ​​do not take all possible values, but only certain values, and they can be recalculated.

In technology, continuous information is called analog. Many human-made devices work with analog information. The beam of the TV picture tube moves across the screen, causing the dots to glow. The stronger the beam, the brighter the glow. The glow changes smoothly and continuously. A turntable, mercury thermometer, and pressure gauge are examples of analog devices. Some home appliances are available in both analog and digital designs. For example, a tonometer is a device for measuring blood pressure. A significant difference is that an analog device can give an absolutely arbitrary value of readings (slightly more or less than a division), and a set of readings digital instrument limited by the number of digits on the indicator. The computer works exclusively with discrete ( digital ) information. Computer memory consists of individual bits, which means it is discrete. Sensors, through which information is perceived, measure mainly continuous characteristics - temperature, load, voltage, etc. The problem of converting analog information into discrete form arises. Idea sampling continuous signal is as follows. Let there be some continuous signal. It can be assumed that for small periods of time, the value of the characteristics of this signal is constant and changes instantly at the end of each interval. "Cutting" the entire time interval into these small pieces and taking the value of the characteristics on each of them, we get a signal with a finite number of values. Thus, it will become discrete. A continuous value is often associated with a graph of a function, and a discrete value is often associated with a table of its values.

This process is calleddigitizing analog signal, and information transformation -analog-to-digital conversion... The conversion accuracy depends on the value discreteness - sampling rates: the higher the sampling rate, the closer the digital information is to the analog quality. But the more calculations a computer has to do and the more information is stored and processed. Information classification

Information can be conditionally divided into various types, based on one or another ion of its property or characteristic, for example, by the method of coding, the sphere of origin, the method of transmission and perception, and public purpose, etc.

• By coding method

According to the method of coding the signal, information can be divided into analog and digital. An analog signal information about the value of the initial parameter, which is reported in the information, is represented in the form of the value of another parameter, which is the physical basis of the signal, its physical carrier. For example, the values ​​of the angles of inclination of the clock hands are the basis for the analog display of time. The height of the mercury column in the thermometer is the parameter that gives analogue information about the temperature. The longer the thermometer stage is, the higher the temperature. To display information in an analog signal, all intermediate values ​​of the parameter are used from the minimum to the maximum, i.e. theoretically an infinite number of them. Digital signal uses as a physical basis for recording and transmitting information only the minimum number of such values, most often only two. For example, in the basis of recording information in a computer, two states of the physical carrier of the signal are used - electrical voltage. One state - there is an electrical voltage, conventionally designated by a unit (1), the other - there is no electrical voltage, conventionally designated by zero (0). Therefore, to transfer information about the value of the initial parameter, it is necessary to use the data representation in the form of a combination of zeros and ones, i.e. digital representation. It is interesting that at one time were developed and used computing machines, which were based on ternary arithmetic, since it is natural to take the following three as the main states of electrical voltage: 1) the voltage is negative, 2) the voltage is zero, 3) the voltage is positive. Still going out scientific work on such machines and describing the advantages of ternary arithmetic. Now the manufacturers of binary machines have won the competition. Will it always be this way? Here are some examples of household digital devices... An electronic clock with digital display provides digital time information. The calculator performs calculations with digital data. A mechanical lock with a digital code can also be called a primitive digital device.

• By sphere of origin

According to the sphere of origin, information can be classified as follows. Information that has arisen in inanimate nature is called elementary, in the world of animals and plants - biological, in human society - social. In nature, living and inanimate, information is carried by: color, light, shadow, sounds and smells. The combination of color, light and shade, sounds and smells creates aesthetic information. Along with natural aesthetic information, as a result of the creative activity of people, another type of information has arisen - works of art. In addition to aesthetic information, semantic information is created in human society as a result of knowledge of the laws of nature, society, and thinking. The division of information into aesthetic and semantic is obviously very conditional, it is just necessary to understand that in one information its semantic part can prevail, and in another the aesthetic one.

• By the way of transmission and perception

According to the method of transmission and perception, it is customary to classify information as follows. Information transmitted in the form of visible images and symbols is called visual; transmitted by sounds - auditory; sensations - tactile; smells - gustatory. Information perceived by office equipment and computers is called machine-oriented information. The amount of machine-oriented information is constantly increasing due to the continuously increasing use of new information technologies in various spheres of human life.

• For public use

For public purposes, information can be divided into mass, special and personal. Mass information is subdivided, in turn, into socio-political, everyday and popular science. Special information is subdivided into production, technical, managerial, and scientific. Technical information has the following gradations:

machine tool,

engineering,

instrumental ...

• Scientific information is divided into biological, mathematical, physical ...
• By the form of presentation

1. Text - information that is contained in printed or written documents or displayed technical devices as text.
2. Graphic - paintings, drawings, photographs, graphs, diagrams, video images on a TV or computer screen.
3. Sound - oral speech, music, noise effects.
4. Numeric - sets of numeric data.
5. Manager - commands and instructions that are transmitted to certain performers (people, animals, robots, CNC machines, computers).
6. Multimedia - information that contains several types of information (cinema).

Information properties

A person needs information not in general, but specifically at the right time to navigate in the world around him and make decisions about further actions.

For information to contribute to making the right decisions, it must be characterized by the following properties:

• usefulness or relevance (compliance with consumer needs);
• credibility (the truth of the state of affairs, the absence of hidden errors);
• fullness (enough for understanding and making a decision);
• relevance or timeliness(importance for the present tense);
• availability (the possibility of obtaining it by a given consumer);
• security (impossibility of unauthorized use or modification);
• ergonomics (convenience of form or volume from the point of view of a given consumer);
• objectivity (does not depend on anyone's opinion);
• intelligibility (clearly expressed).
• Completeness (information is complete if it is sufficient to make decisions)
• Accuracy (determined by the degree of proximity to the real state of an object, process, phenomenon)

Information properties are subdivided into:

Attributive;

Pragmatic;

Dynamic.

Attributive are those properties without which information does not exist. Pragmatic properties characterize the degree of usefulness of information for the user, consumer and practice. Dynamic properties characterize the change in information over time.

Discreteness

The attributive properties of information, which must be paid attention to, is the property of discreteness. The information contained in the information, knowledge is discrete, i.e. characterize individual factual data, patterns and properties of the objects under study, which are distributed in the form of various messages consisting of a line, composite color, letter, number, symbol, sign.

Continuity

Information tends to merge with the already recorded and accumulated earlier, thereby contributing to the progressive development and accumulation. This confirms another attributive property of information - continuity.

Sense and novelty

The pragmatic properties of information are manifested in the process of using information. First of all, we refer to this category of properties as the presence of meaning and novelty of information, which characterizes the movement of information in social communications and highlights that part of it that is new for the consumer.

Utility

Information is called useful information that reduces the uncertainty of information about an object. Misinformation is regarded as negative values useful information... There is a use of the term usefulness of information to describe what effect the incoming information has on the internal state of a person, his mood, well-being, and finally health. In this sense, useful or positive information is one that is happily perceived by a person, contributes to the improvement of his well-being, and negative information has a depressing effect on the psyche and well-being of a person, can lead to deterioration of health, a heart attack, for example.

Value

The next pragmatic property of information is its value. It should be noted that the value of information is different for different consumers and users.

Cumulativeness

The cumulative property characterizes the accumulation and storage of information.

Information growth

First of all, it is necessary to note the property of information growth. The movement of information in information communications and its constant dissemination and growth determine the property of multiple dissemination or repetition. Although the information is language-specific and media-specific, it is not strictly language-specific or media-specific. Thanks to this, information can be obtained and used by several consumers. This is a property of reusability and a manifestation of the property of scattering information over various sources.

Aging

Among the dynamic properties, it is also necessary to note the property of information aging.

Information(from lat.informatio, explanation, presentation, awareness) - any information and data reflecting the properties of objects in natural, social and technical systems and transmitted by sound, graphic (including written) or in any other way without the use or with the use of technical means.

Information classification

Information can be divided into types according to various criteria:

1. onway of perception:

Visual - perceived by the organs of vision.

Auditory - perceived by the organs of hearing.

Tactile - Perceived by tactile receptors.

Olfactory - perceived by the olfactory receptors.

Gustatory - perceived by the taste buds.

2.onform of presentation:

Text - transmitted in the form of symbols intended to denote tokens of the language.

Numeric - in the form of numbers and signs indicating mathematical operations.

Graphic - in the form of images, objects, graphs.

Sound - oral or in the form of recording and transmission of language lexemes.

3. onappointment:

Massive - contains trivial information and operates with a set of concepts that are understood by most of the society.

Special - contains a specific set of concepts, when used, information is transmitted that may not be understood by the bulk of society, but are necessary and understandable within a narrow social group where this information is used.

Secret - transmitted to a narrow circle of people and through closed (protected) channels.

Personal (private) - a set of information about a person that determines the social status and types of social interactions within the population.

4. onmeaning:

Relevant - information that is valuable at a given time.

Reliable - information received without distortion.

Understandable - information expressed in a language that is understandable to the person to whom it is intended.

Complete - information sufficient to make a correct decision or understanding.

Useful - the usefulness of the information is determined by the subject who received the information, depending on the scope of possibilities for its use.

5. ontruth:

true

Information has the following properties:

credibility

Information is reliable if it reflects the true state of affairs. Inaccurate information can lead to misunderstandings or incorrect decisions. Reliable information has the property of becoming outdated, that is, it ceases to reflect the true state of affairs.

Information is complete if it is sufficient for understanding and making decisions. Both incomplete and redundant information hinders decision making or can lead to errors.

accuracy

The accuracy of information is determined by the degree of its proximity to the real state of an object, process, phenomenon.

value

The value of information depends on how important it is for solving the problem, as well as on how much later it will find application in any kind of human activity.

timeliness

Only timely information can bring the expected benefits. Both the premature presentation of information (when it cannot yet be assimilated) and its delay are equally undesirable.

intelligibility

If valuable and timely information is expressed in an incomprehensible way, it can become useless. Information becomes understandable if it is expressed in the language spoken by those to whom the information is intended.

availability

Information should be presented in an accessible (by the level of perception) form. Therefore, the same questions are presented in different ways in school textbooks and scientific publications.

brevity

Information on the same issue can be presented briefly (concisely, without insignificant details) or at length (in detail, verbose). Brevity of information is necessary in reference books, encyclopedias, all kinds of instructions.

Amount of information can be considered as a measure of reducing the uncertainty of knowledge when receiving information messages. This allows information to be quantified. There is a formula that connects the number of possible information messages N and the amount of information I carried by the received message: N = 2 i(Hartley's formula). Sometimes it is written differently. Since the occurrence of each of the N possible events has the same probability p = 1 / N, then N = 1 / p and the formula has the form I = log 2 (1 / p) = - log 2 p

If the events are uneven, then: h i = log 2 1/ p i = - log 2 p i ,

where p i is the probability of the i-th character of the alphabet in the message. It is more convenient to use as a measure of the amount of information not the value of h i, but the average value of the amount of information per one character of the alphabet H = Sp i h i = - Sp i log 2 p i

The value of H reaches a maximum at equiprobable events, that is, when all p i p i = 1 / N

In this case, Shannon's formula turns into Hartley's formula.

Per unit of information the amount of information is accepted, which is contained in the information message, which halves the uncertainty of knowledge. Such a unit is named bit.

The minimum unit for measuring the amount of information is a bit, and the next largest unit is a byte, and:

1 byte = 8 bits = 2 3 bits.

In computer science, the education system of multiple units of measurement is somewhat different from those adopted in most sciences. Traditional metric systems of units, for example, the International System of Units SI, use the coefficient 10 n as the multipliers of multiple units, where n = 3, 6, 9, etc., which corresponds to the decimal prefixes "Kilo" (10 3), "Mega" (10 6), "Giga" (10 9), etc.

In a computer, information is encoded using a binary sign system, and therefore the coefficient 2 n is used in multiple units of measuring the amount of information

So, multiple byte units of measurement of the amount of information are entered as follows:

1 kilobyte (KB) = 2 10 bytes = 1024 bytes;

1 megabyte (MB) = 2 10 KB = 1024 KB;

1 gigabyte (GB) = 2 10 MB = 1024 MB.

The amount of information in the message. The message consists of a sequence of characters, each of which carries a certain amount of information.

If the characters carry the same amount of information, then the amount of information I c in the message can be calculated by multiplying the amount of information I 3 that one character carries by the length of the code (the number of characters in the message) K:

I c = I s  K

So, each digit of a binary computer code carries information in 1 bit. Consequently, two digits carry information in 2 bits, three digits - in 3 bits, etc. The amount of information in bits is equal to the number of digits of a binary computer code

Information entropy is a measure of the uncertainty or unpredictability of information, the uncertainty of the appearance of any symbol of the primary alphabet. In the absence of information losses, it is numerically equal to the amount of information per symbol of the transmitted message.

Entropy is the amount of information per one elementary message of a source generating statistically independent messages.

Entropy came to be used as a measure of useful information in the transmission of signals over wires. By information, Shannon meant signals that were necessary, useful to the recipient. Unhelpful signals, from Shannon's point of view, are noise, interference. If the signal at the output of the communication channel is exact copy signal at the input then, from the point of view of information theory, it means the absence of entropy. No noise means maximum information. The relationship between entropy and information is reflected in the formula: H + Y = 1

where H is entropy, Y is information. This conclusion was quantitatively substantiated by Brillouin.

To calculate entropy, Shannon proposed an equation that resembles the classical expression for entropy found by Boltzmann. H = ∑ P i log 2 1/ P i = -∑ P i log 2 P i ,

where H is Shannon's entropy, P i is the probability of some event.

Information binary entropy for independent random events with possible states (from to, is a probability function) is calculated by the formula:

This value is also called the average entropy of the message. The quantity is called the partial entropy, which characterizes only the -e state.

Thus, the entropy of an event is the sum with the opposite sign of all the products of the relative frequencies of occurrence of the event, multiplied by their own binary logarithms. This definition for discrete random events can be extended to the probability distribution function.

Features information consist in the fact that it is not matter or energy, although it reflects reality in the form of the distribution of matter and energy in time and space and the processes of their redistribution. but information is property of only living organisms capable of recording information. Source of information for living organisms are the senses.

Information is not material, although for its existence you need (initially - proteins in the body of the body). As a rule, the more complex an object of the material world or a process, the more information it carries in itself and, conversely, the more complex an organism that collects information, the more options for its behavior can correspond to the same information received.

Concept and types of information

Knowledge as acquired and preserved information about the surrounding objects and phenomena, are vital for all living organisms. A person, unlike other living organisms, can use special devices that allow him to expand knowledge that would be impossible to obtain through the senses. In addition, a person can use a variety of tangible media, with which you can convey information the rest of the people who were not personally present at the collection of information, but in general, are interested in having it.

Definition of information

Exist definition of information from K. Shannon, according to which:

definition of information is the removed uncertainty, i.e. information that should remove the uncertainty that exists in the consumer to one degree or another before they are received, expand his understanding of the object with useful information.