All information that a computer processes must be represented in binary code using two digits 0 and 1. These two characters are commonly called binary digits or bits. With the help of two digits 0 and 1, any message can be encoded. This was the reason that two important processes must be organized in a computer: encoding and decoding. Encoding is the transformation of input information into a form that is perceived by a computer, i.e. binary code. Decoding is the transformation of data from a binary code into a human-readable form.
From the point of view of technical implementation, the use of the binary number system for encoding information turned out to be much simpler than the use of other methods. Indeed, it is convenient to encode information as a sequence of zeros and ones, if these values are represented as two possible stable states of an electronic element: 0 - no electrical signal; 1 - the presence of an electrical signal. These states are easy to distinguish. The disadvantage of binary coding is long codes. But in engineering it is easier to deal with a large number of simple elements than with a small number of complex ones.
You have to constantly deal with a device that can only be in two stable states: on/off. Of course, this is a well-known switch. But it turned out to be impossible to come up with a switch that could stably and quickly switch to any of the 10 states. As a result, after a number of unsuccessful attempts, the developers came to the conclusion that it was impossible to build a computer based on the decimal number system. And it was precisely the binary number system that was put in the basis of the representation of numbers in a computer.
Analog and Discrete Coding A person is able to perceive and store information in the form of images (visual, sound, tactile, gustatory and olfactory). Visual images can be stored in the form of images (drawings, photographs, and so on), and sound images can be recorded on records, magnetic tapes, laser discs, and so on. Information, including graphics and sound, can be presented in analog or discrete form. With an analog representation, a physical quantity takes on an infinite number of values, and its values change continuously. With a discrete representation, a physical quantity takes on a finite set of values, and its value changes abruptly.
Examples Let us give an example of analog and discrete representation of information. The position of the body on the inclined plane and on the stairs is specified by the values of the X and Y coordinates. When the body moves along the inclined plane, its coordinates can take on an infinite number of continuously changing values from a certain range, and when moving up the stairs, only a certain set of values, and changing abruptly. An example of an analog representation of graphic information can be, for example, a painting canvas, the color of which changes continuously, and a discrete image printed with an inkjet printer and consisting of individual dots of different colors. An example of analog storage of sound information is a vinyl record (the sound track changes its shape continuously), and a discrete audio CD (the sound track of which contains areas with different reflectivity).
The conversion of graphic and sound information from analog to discrete form is carried out by sampling, that is, by dividing a continuous graphic image and a continuous (analogue) sound signal into separate elements. In the process of discretization, coding is performed, that is, the assignment of a specific value to each element in the form of a code. Discretization is the transformation of continuous images and sound into a set of discrete values in the form of codes. Sampling
Image Encoding There are two ways to create and store graphic objects on your computer - as a bitmap image or as a vector image. Each image type has its own encoding method. A raster image is a collection of dots (pixels) of different colors. Pixel - the minimum area of the image, the color of which can be set independently.
In the process of encoding an image, its spatial sampling is performed. Spatial discretization of an image can be compared to building an image from a mosaic ( a large number small multi-colored glasses). The image is divided into separate small fragments (dots), and each fragment is assigned the value of its color, that is, a color code (red, green, blue, and so on). For a black and white image, the information volume of one point is equal to one bit (either black or white - either 1 or 0). For four color - 2 bits. 8 colors require 3 bits. For 16 colors - 4 bits. For 256 colors - 8 bits (1 byte). Image quality depends on the number of dots (the smaller the dot size and, accordingly, the greater their number, the better quality) and the number of colors used (the more colors, the better the image is encoded). Image encoding
The image depends on the number of dots (the smaller the dot size and, accordingly, the greater their number, the better the quality) and the number of colors used (the more colors, the better the image is encoded). To represent a color in the form of a numeric code, two color models are used that are inverse to each other: RGB or CMYK. The RGB model is used in televisions, monitors, projectors, scanners, digital cameras... The main colors in this model are: red (Red), green (Green), blue (Blue). The CMYK color model is used in printing when forming images intended for printing on paper. Color images can have different color depths, which are given by the number of bits used to encode the color of a point. If we encode the color of one point in the image with three bits (one bit for each RGB color), then we get all eight different colors. Image encoding
In practice, to store information about the color of each point of a color image in the RGB model, 3 bytes (i.e. 24 bits) are usually allocated - 1 byte (i.e. 8 bits) for the color value of each component. Thus, each RGB component can take a value in the range from 0 to 255 (total 2 8 = 256 values), and each point of the image, with such a coding system, can be painted in one of the colors. Such a set of colors is usually called True Color (true colors), because the human eye is still not able to distinguish a greater variety. In order for an image to be formed on the monitor screen, information about each dot (dot color code) must be stored in the video memory of the computer. Let's calculate the required amount of video memory for one of the graphics modes. In modern computers, the screen resolution is usually 1280 x 1024 pixels. Those. total 1280 * 1024 = dots. With a color depth of 32 bits per point, the required amount of video memory is: 32 * = bits = bytes = 5120 KB = 5 MB. Image encoding
Raster images are very sensitive to scaling (enlargement or reduction). When a raster image is reduced, several neighboring pixels are converted into one, so the visibility of fine details of the image is lost. Enlarging the image increases the size of each dot and produces a step effect that can be seen with the naked eye. Image encoding
Coding of vector images A vector image is a collection of graphic primitives (point, segment, ellipse...). Each primitive is described by mathematical formulas. The encoding depends on the application environment. The advantage of vector graphics is that the files that store vector graphics are relatively small. It is also important that vector graphics can be enlarged or reduced without loss of quality.
Graphic file formats Graphic file formats determine how the information in the file is stored (raster or vector) and how the information is stored (the compression algorithm used). The most popular raster formats are: BMP GIF JPEG TIFF PNG Bit MaP image (BMP) is a universal raster graphic file format used in the Windows operating system. This format is supported by many graphic editors, including the Paint editor. Recommended for storing and sharing data with other applications. Tagged Image File Format (TIFF) is a raster image file format supported by all major graphics editors and computer platforms. Includes a lossless compression algorithm. Used to exchange documents between different programs. Recommended for use when working with publishing systems.
Graphics Interchange Format (GIF) bitmap graphics file format supported by applications for various operating systems. Includes a lossless compression algorithm that allows you to reduce the file size by several times. Recommended for storing images created programmatically (diagrams, graphs, and so on) and drawings (such as appliqué) with a limited number of colors (up to 256). Used to place graphics on Web pages on the Internet. Portable Network Graphic (PNG) Bitmap graphic file format similar to GIF. Recommended for placing graphics on Web pages on the Internet. The Joint Photographic Expert Group (JPEG) is a bitmap graphics file format that implements an efficient compression algorithm (JPEG method) for scanned photographs and illustrations. The compression algorithm allows you to reduce the size of the file dozens of times, however, it leads to the irreversible loss of some information. Supported by applications for various operating systems. Used to place graphics on Web pages on the Internet.
Binary Audio Coding The use of the computer to process audio began later than numbers, text, and graphics. Sound is a wave with continuously changing amplitude and frequency. The greater the amplitude, the louder it is for a person, the greater the frequency, the higher the tone. Sound signals in the world around us are extremely diverse. Complex continuous signals can be represented with sufficient accuracy as the sum of a certain number of simple sinusoidal oscillations. Moreover, each term, that is, each sinusoid, can be precisely specified by a certain set of numerical parameters - amplitude, phase and frequency, which can be considered as a sound code at some point in time. In the process of encoding an audio signal, its temporal sampling is performed - a continuous wave is divided into separate small time sections and a certain amplitude value is set for each such section. Thus, the continuous dependence of the signal amplitude on time is replaced by a discrete sequence of loudness levels (see figure).
Each volume level is assigned its code. The more volume levels will be selected in the process of encoding, the more information will carry the value of each level and the better the sound will be. The quality of binary audio encoding is determined by the encoding depth and sampling rate. Sampling frequency - the number of measurements of the signal level per unit of time. The number of volume levels determines the encoding depth. Modern sound cards provide 16-bit audio encoding depth. In this case, the number of volume levels is N = 2 I = 2 16 = Binary audio coding
Representation of video information Recently, the computer is increasingly used to work with video information. The simplest such work is watching movies and video clips. It should be clearly understood that the processing of video information requires a very high speed of the computer system. What is a film in terms of computer science? First of all, it is a combination of sound and graphic information. In addition, to create the effect of movement on the screen, a discrete technology for quickly changing static pictures is used. Studies have shown that if more than one frame is replaced in one second, then the human eye perceives changes in them as continuous. It would seem that if the problems of coding static graphics and sound are solved, then it will not be difficult to save the video image. But this is only at first glance, because, as the example discussed above shows, using traditional methods of storing information, the electronic version of the film will turn out to be too large. A fairly obvious improvement is to remember the first frame in its entirety (in the literature it is customary to call it a key frame), and in the following ones to save only differences from the initial frame (difference frames).
There are many different formats for presenting video data. In the Windows environment, for example, for more than 10 years (since version 3.1) the Video for Windows format has been used, based on universal files with the AVI extension (Audio Video Interleave - interleaving audio and video). More versatile is multimedia format Quick Time originally originated on Apple computers. Recently, video image compression systems have become more widespread, allowing some distortions of the image that are invisible to the eye in order to increase the compression ratio. The most famous standard of this class is MPEG (Motion Picture Expert Group), which is developed and constantly developed by the Committee (group of experts) of the international organization ISO / IEC (International Standards Organization / International Electrotechnical Commission) established in 1988 on high-quality compression standards for moving images. The methods used in MPEG are not easy to understand and rely on fairly complex mathematics. A technology called DivX (derived from the abbreviation of Digital Video Express) has become more widespread. Thanks to DivX, it was possible to achieve a compression ratio that made it possible to fit a high-quality recording of a full-length film onto one CD - to compress a 4.7 GB DVD movie to 650 MB. Presentation of video information
Multimedia Multimedia (multimedia, from the English. multi - a lot and media - media, environment) - a set of computer technologies that simultaneously use several information media: text, graphics, video, photography, animation, sound effects, high-quality sound. The word "multimedia" means the impact on the user through several information channels simultaneously. You can also say this: multimedia is the combination of an image on a computer screen (including graphic animation and video frames) with text and sound. Multimedia systems are most widely used in education, advertising, and entertainment.
Uncertainty of knowledge and unit of information 1 bit A message that reduces the uncertainty of knowledge by half carries 1 bit of information. The uncertainty of knowledge about some event is the number of possible outcomes of the event (tossing a coin, a die; drawing lots)
Examples of the amount of information Book page 2.5 KB Textbook 0.5 MB Great Soviet Encyclopedia 120 MB Newspaper 150 KB Black and white television frame 300 KB Color frame of 3 colors 1 MB 1.5-hour color feature film 135 GB
100 MB can fit: Text pages 150 highest quality color slides Audio recording 1.5 hours CD-quality music piece - stereo 10 minutes High-quality recording film 15 seconds Bank account transactions records For 1000 years
Copy the tasks in your notebook and solve them yourself. 1. Arrange the values in descending order: 1024 bits, 1000 bytes, 1 bit, 1 byte, 1 KB. 2. The information volume of one message is 0.5 KB, and the other - 500 bytes. By how many bits is the information volume of the first message greater than the volume of the second message? 3. The 64-character alphabet was used to write the text. What is the amount of information in bytes contained in 10 pages of text if each page has 32 lines of 64 characters per line? 4. An information message of 375 bytes consists of 500 characters. What is the informational weight of each character in this message? What is the power of the alphabet with which this message was written? 5. How many Kilobytes of information contain messages of the following size: 216 bits, 216 bytes, ¼ Megabyte? 6. The student's essay on computer science has a volume of 20 kilobytes. Each page of the abstract contains 32 lines of 64 characters per line, the capacity of the alphabet is 256 characters. How many pages are in the abstract? 7. The data transfer rate on a certain channel is equal to bits / sec. Transferring the file over this communication channel took 16 seconds. Specify the size of the file in kilobytes. Tasks
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Slides captions:
Visual forms of information presentation
text Types of information according to the method of presentation numerical graphic sound
text is the transfer of speech, thoughts, reasoning into the form of a text - a combination of letters, and different languages have their own set of characters. An example is books, various documents, protocols, etc.
numeric data expressed as special characters - numbers, numbers. Necessary for, for example, economic relations. An example is price tags in stores, data from various appliances, etc.
graphic is the most ancient way of displaying and transmitting information. These are different images. Examples are rock art, frescoes, paintings, diagrams, drawings, diagrams, etc.
sound is the oldest type of information based on sound vibrations. Examples are human speech, music, various kinds of signaling, etc.
in front of you text information. Read it and try to imagine the picture. A fiery glow colored the sky. The surface of the ocean seemed to be covered with a scarlet silk scarf. The mountains were a black stripe on the horizon. How do you think it is easier to perceive information: from a picture or from text?
You have text information. Read it and try to imagine the picture. On a summer sunny day, two boys and two girls played on the playground, two of them played with a ball, and the rest played with spatulas. It is known that one girl accurately played the ball, and one boy accurately played with a spatula. With what kind of information can we get a better visual representation? In what form can we present this information?
Forms of presentation of visual and information: Drawings - help to quickly understand what is at stake, and create images. Diagrams - Diagrams show how the surrounding objects are arranged and how they are related to each other. Charts - used to represent different numerical data.
Saint Petersburg city map
Schemes and symbols
Task: It is known that someone arranged all the letters of the alphabet in a circle and replaced each letter of the original message with the next one after it. Decode the resulting encryptions: E Y B D S B N N B
Elephant - 60 years old Horse - 25 years old Camel - 30 years old Crocodile - 40 years old Chimpanzee - 60 years old
Charts are usually divided according to their form into the following types: bar charts; bar charts; pie charts; line charts; curly charts;
1. type of chart, the columns of which are arranged horizontally; 2. the type of information presented as an image; 3. graphical representation of data, allowing you to quickly evaluate the ratio of several quantities. 4. a list, a list of information, numerical data, given in a certain system and arranged in columns. 5. the oldest type of information based on sound vibrations. 6. an object with information fixed by a man-made method for its transmission. 7. materially expressed replacement of objects, phenomena, concepts in the process of information exchange. 8. data expressed as special characters - numbers, numbers. 9. an illustration that, with the help of conventional graphic symbols, conveys the essence of the structure of an object or system, movement, structure, etc. 10. several sentences connected between. itself in meaning. S V U K V D T O I L G I A B S I R A B A Z L A V O R I N O S T E F R I O A V K H E Y I A C K K A E L F M A U Y M S A E M M A T Y S A E K N A T Y 1 2 3 4 5 6 7 8 9 10
The presentation is aimed at organizing work with the texts of the training paragraph. The entire text is divided into parts, in which only the main content is stated. The parts are placed on separate slides. The content of each part is composed of a task. Since these are self-training technologies, the tasks do not provide for automatic verification of the results. But the content of all tasks will be included in the final control test. The possibility of external verification of the execution of tasks is provided. Macros are used for this purpose. On a slide in demo mode, you need to write answers using the keyboard, as well as an alias. Then print this slide. If the work is done in a classroom, an anonymous peer review should be organized. It is for this purpose that pseudonyms are used. The results of the check should be entered in the rating sheet of the class. Each correct answer is worth one point. The total number of points is 26. It is not recommended to force students to memorize educational texts. Computer technologies for self-training and self-testing will ensure conscious assimilation of the subject content.
3.1 Tabular presentation of information The presentation of information in tabular form is widespread. You can easily and quickly find the necessary information in the table. A table is the simplest graphic representation of a material. They are made up of columns and rows. The number of columns and rows can be different. With the help of computers, tables can be arranged in different ways: choose the required number of columns and rows, use different colors to fill tables, you can even create the effect of table movement. According to their purpose, tables are divided into three types. 1. Explanatory tables - present the material in a concise manner, which makes it easier to understand. 2. Comparison tables- in them information is compared and compared. 3. Generalizing or thematic tables - they summarize in a certain sequence the main properties and signs of objects, phenomena, events. Complete task number 1. Use the mouse to place the cursor in the answer windows, and use the keyboard to write down the answer.
Look at the table and write down in the first answer what kind it belongs to. In the second answer, write down what the rectangular tables are made of. In the third answer, write down the name of the device that allows you to quickly change the appearance of tables. alias
Exercise 1
Tables of type "Object - property" Rectangular tables consist of rows and columns, which are also called graphs. The headings of the graphs are usually located in the top row of the table. In tables of the "object-property" type, each row refers to an object. In the first column, this is usually indicated by an object, in other columns, the properties of the object are indicated. Tables of the "Object - object" type In tables of the "object-object" type, relationships between various objects. Any data can be reduced to a tabular form. Bringing information to tabular form is called data normalization. A variety of tables of this type are "binary matrices". They display the presence of a connection between objects: for example, if there is a connection, then 1 is set, if not, then 0. The matrix form of tables is convenient for computer processing, so many computer technologies work with tables. There are special programs for processing tables. Complete task number 2. Use the mouse to place the cursor in the cells of the table, and use the keyboard to write the numbers 0 or 1.
The concept of information is a fundamental concept of informatics. Any human activity is a process of collecting and processing information, making decisions on its basis and their implementation. With the advent modern means computer technology, information began to act as one of the most important resources of scientific and technological progress
The term "information" comes from the Latin informatio explanation, exposition, awareness. The Encyclopedic Dictionary (M.: Sov. encyclopedia, 1990) defines information in historical evolution: initially information transmitted by people orally, in writing or in another way (with the help of conditional signals, technical means, etc.); since the middle of the 20th century, a general scientific concept that includes the exchange of information between people, a person and an automaton, the exchange of signals in the animal and plant world (the transfer of signs from cell to cell, from organism to organism).
Related to the concept of information are concepts such as signal, message, and data. A signal (from the Latin signum sign) is any process that carries information. A message is information presented in a specific form and intended to be transmitted. Data is information presented in a formalized form and intended for its processing. technical means e.g. computer.
Classification: Identification of the nomenclature to be coded. It includes those details - signs that are used to compile groupings. For each nomenclature, a complete list of all items to be coded is compiled. At the same time, the logical dependence of various features in the nomenclature under consideration is observed. For example, when coding a territory, districts are organized into regions. Such an ordered list is called a nomenclature. Each nomenclature provides for a certain number of reserve positions in case new objects appear. Thus, the classification consists in the distribution of the elements of the set into subsets based on features and dependencies within the features.
When creating IS of automated information networks, the following work is performed: The composition of economic tasks and the system of indicators for each level of processing are determined; The composition and methods of information exchange between different levels processing; An information fund is being created and distributed; Various forms of information input on a PC are created, taking into account multi-level data processing; Consideration is given to the use various kinds classifiers and the creation of local classifiers of economic information is provided; Various forms of information output are created; Issues of information and reference services for users, building standard queries are being developed; Automated information systems are being created that provide direct contact between the user and the PC (development of a dialogue script, structure, menu); The issues of organization on the PC of office work are being worked out management activities, control of execution of documents; Information interaction is being created with external environment based on email organization.
The creation of IO is carried out in the course of drawing up a technological project and provides for the preparation of instructions for users on the application of the main provisions of IO in their practical activities associated with the processing of economic tasks on a PC. These are: Instructions for preparing documents for machine processing and their coding; Handling instructions economic task on a PC - entering a program, correcting information arrays, correcting information, loading into a database, organizing queries, obtaining output data.
The concept of information is a fundamental concept of informatics. Any human activity is a process of collecting and processing information, making decisions on its basis and their implementation. With the advent of modern computer technology, information began to act as one of the most important resources of scientific and technological progress.
Information is contained in human speech, texts of books, magazines and newspapers, radio and television messages, instrument readings, etc. A person perceives information with the help of the senses, stores and processes it with the help of the brain and central nervous system. The transmitted information usually concerns some objects or ourselves and is associated with events taking place in the world around us.
Within the framework of science, information is a primary and indefinable concept. It assumes the existence of a material carrier of information, a source of information, an information transmitter, a receiver, and a communication channel between the source and the receiver. The concept of information is used in all areas: science, technology, culture, sociology and everyday life. The specific interpretation of the elements associated with the concept of information depends on the method of a particular science, the purpose of the study, or simply on our ideas.
A narrower definition is given in technology, where this concept includes all information that is the object of storage, transmission and transformation. The most general definition takes place in philosophy, where information is understood as a reflection of the real world. Information as a philosophical category is considered as one of the attributes of matter, reflecting its structure.
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There are two forms of information representation: continuous and discrete. Since signals are information carriers, physical processes of various nature can be used as the latter. For example, the flow process electric current in a chain, the process of mechanical movement of a body, the process of light propagation, etc. Information is represented (reflected) by the value of one or more parameters of the physical process (signal), or a combination of several parameters.
On fig. 1.1 in the form of graphs are shown: a) signal Xn, continuous in level and in time; b) discrete in terms of level and continuous in time signal Xdn; c) signal Xnd, continuous in level and discrete in time; d) Xdd signal discrete in level and time. Rice Species information processes
Finally, all the variety of information surrounding us can be grouped according to various criteria, that is, classified by type. For example, depending on the field of origin, information reflecting the processes and phenomena of inanimate nature is called elementary, the processes of an animal and flora biological, human society social.
According to the method of transmission and perception, the following types of information are distinguished: visual transmitted by visible images and symbols, auditory sounds, tactile sensations, organoleptic smells and tastes, machine issued and perceived by computer technology, etc.
The amount of information is called the numerical characteristic of the signal, reflecting the degree of uncertainty (incompleteness of knowledge) that disappears after receiving a message in the form of a given signal. This measure of uncertainty in information theory is called entropy. If, as a result of receiving a message, complete clarity is achieved on some issue, they say that complete or exhaustive information was received and the need to receive additional information no. Conversely, if after receiving the message the uncertainty remains the same, then no information was received (zero information).
The above reasoning shows that there is a close relationship between the concepts of information, uncertainty and choice. So, any uncertainty implies the possibility of choice, and any information, reducing uncertainty, reduces the possibility of choice. With complete information, there is no choice. Partial information reduces the number of choices, thereby reducing uncertainty.
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