Presentation on the topic of coding text information. Presentation on the topic "Coding text (character) information." Binary coding of text information

07.04.2024

“Texts in computer memory” - Texts in computer memory. "Abracadabra". Coding of texts. Encoding table, international standard ASCII. The word will take 14 bytes = 112 bits of memory, because 1 byte = 8 bits. Example 1: How many bits of computer memory does the word MICROPROCESSOR occupy? Computer alphabet. Principle of sequential alphabet coding:

“Coding in computer science” - What is it about? where is it stored? how is it encoded? Comparison chart. Solving information coding problems. The essence of coding. Homework: Gen. DNA structure. Properties of the genetic code. Storage of hereditary information. ABOUT WHAT? Hereditary information. Genetic code.

“Determining the amount of information” - Objectives To study methods for determining the amount of information: quantitative; alphabetical. N=2I. Not matter and not energy...? We measure... An alphabetical approach to quantifying information. Amount of information. Don't be surprised, information can be measured quantitatively. Goal: find out how information can be measured.

“Sign systems for information coding” - Information coding. What methods and senses does a person use when reproducing information? Electromagnetic waves (radio, television, cell phone). Method of perception: Visual. Give examples of the use of information and communication technologies. Encoding information using sign systems.

“System of signs” - Homework (prepare for the survey): Give examples of sign systems. Encoding information using sign systems. 1. Signs: form and meaning. Encoding of information. For long-term storage, signs are recorded on storage media. The sign system is based on a set of signs called the alphabet.

“Numbers on a computer” - +. Forms for writing signed integers. Representation of numbers in computer memory. The number 3910 = 100111 2 in double-byte format: 1) A and B are positive: Signed numbers. They have different ideas. 3) A – positive, B – negative, |B|<|A|. Арифметические действия. Число 3910 = 100111 2 в однобайтовом формате:

There are a total of 15 presentations in the topic

Slide 3

Historical reference

Cryptography is secret writing, a system of changing writing in order to make the text incomprehensible to the uninitiated Morse code or uneven telegraph code, in which each letter or sign is represented by its own combination of short elementary messages of electric current (dots) and elementary messages of triple duration (dash) Signature gestures - sign language used by people with hearing impairments Question: What other examples of coding text information can be given?

Slide 4

Coding examples

“Hello, Sasha!” Russian text – in Latin letters “Zdravstvuy, Sasha!” Semaphore (position) Rock painting – BISON Hieroglyph “Fish Trader” (China)

Slide 5

Caesar Code

A B C D E E F G H I J J K L M N O P R S T U V X C CH W Y Y Y J1 Julius Caesar (1st century BC) Replace each letter of the encrypted text with another by shifting the alphabet from the original letter by a fixed number of characters! Let's encode BAY T - shift it 2 characters to the right We get: G V L F

Slide 6

Exercise:

Decipher the phrase of the Persian poet Jalaleddin Rumi “kgnusm yoogkg fesl ttsfhya fzuzhschz fhgrzkh yoogksp” encoded using the Caesar cipher. It is known that each letter of the source text is replaced by the third letter after it. Rumi 1207-1273 A B C D E E F G H H I J K L M N O P R S T U V H C CH W Q Y Y Z Answer: Close your eyes, let your heart become an eye

Slide 7

Binary coding of text information

To represent text information in a computer, an alphabet with a capacity of 256 characters is used. One character of such an alphabet carries 8 bits of information: 28=256, 8 bits=1 byte, therefore, the binary code of each character in a computer text occupies 1 byte of memory 1 byte 256 characters 66 letters of the Russian alphabet 52 letters of the English alphabet 0-9 digits Hello! 1001011

Slide 8

ASCII code table

AmericanStandard Code for Information Interchange codes from 0 to 32 function keys codes from 33 to 127 letters of the English alphabet, symbols of mathematical operations, etc.

Slide 9

Russian character encoding tables

KOI8-R CP1251 CP866

Slide 10

Slide 11

Working in the text editor MS Word

Launch the text editor MS Word. While holding down the ALT key, enter the codes on the additional numeric keypad: 161 168 226 What word did you get? Answer: bit

Slide 12

Unicode encoding

1 character - 2 bytes (16 bits), which can be encoded? characters

Slide 13

Amount of information in a message

Imessage=Icharacter* K Imessage - information volume of message Icharacter - information volume of character (alphabet power) K – number of characters

Slide 14

Calculation of the amount of text information

Create a text document in MS Word and type the proverb in it: Learning is a chieftain, lack of learning is a mosquito. Question: How many characters? Question: What is the information volume of the file?

Slide 15

Tasks

What is the power of the alphabet with which a message containing 2048 characters is written, if its size is 1.25 KB. Arithmetically convert the information volume of the message into bits: I = 10,240 bits Determine the number of bits per character: 10,240 bits: 2,048 = 5 bits Using the formula N = 2I, determine the number of characters in the alphabet: N = 2I = 25 = 32

Slide 16

The phrase has 108 characters, including punctuation, quotation marks and spaces. How many bits of information does this phrase carry? The Canon LBP laser printer prints at an average speed of 6.3 Kbps. How long will it take to print 8 pages of a document, if you know that one page has an average of 45 lines and 70 characters per line (1 character – 1 byte).

Slide 17

What is the power of the alphabet with which a message containing 2048 characters is written if its volume is 1/512 of one megabyte. A computer user with good keyboard input skills can enter 100 characters per minute. The power of the alphabet used in a computer is 256. How much information in bytes can a user enter into a computer in 1 minute.

Slide 18

Questions:

1. What principle of encoding text information is used in a computer? 2. What is the name of the international character encoding table? 3. List the names of encoding tables for Russian characters.

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Piyaeva Olga Nikolaevna

Place of work: municipal budgetary educational institution "Taraskovskaya secondary school"

Job title: IT-teacher

School address: Moscow region, Kashira district, Taraskovo village, Komsomolskaya street, 22

Grade: 8

Lesson topic: Coding of text information. (first lesson on the topic “Encoding information”)

Lesson type: learning new knowledge

Lesson type: traditional using information technology

Goals:

Educational:

introduce students to ways of encoding information in a computer;

consider examples of problem solving;

Developmental:

promote the development of students' cognitive interests.

Educational:

cultivate endurance and patience in work, feelings of camaraderie and mutual understanding.

Tasks:

Educational:

to form students’ knowledge on the topic “Coding text information”;

Developmental:

develop skills of analysis and self-analysis;

promote the formation of imaginative thinking in schoolchildren;

Educational:

develop the ability to plan your activities.

Equipment:

student workplaces (personal computer),

teacher's workplace,

multimedia projector,

Software: PC, PowerPoint, tables, diagrams.

Lesson Information Card:

№ p/p

Lesson stage

At-

measure-

new time

Didactic

what's the goal

Forms and methods of work

Types of student activities

Organizational

moment

2 minutes

Include students in the business rhythm, prepare the class for work

Teacher's oral message

Productivity mindset

new activity

ness

Studying

new

material

18 min

Form cognitive motives. Ensure that students accept the purpose of the lesson. Form concrete ideas about the coding of text information.

Explanation of new material using

presentation

Listening and memorizing, answering teacher questions, completing decoding tasks

information

Physical education minute

2 minutes.

Prevent children from getting tired

Doing exercises

Consolidation of acquired knowledge

10 min.

Organize activities to apply new knowledge

Practical work

Execution of practical

good work

Initial check of understanding

8 min

Identify the level of primary assimilation of new material

Frontal survey

Differentiated independent work

Answer teacher questions

Perform independent work

Homework

2 minutes.

Provide information on homework and instructions for completing it.

Homework instructions

Recording homework in diaries

Summing up the lesson (reflection)

3 min.

Self-analysis of students' understanding of the topic

Acceptance of an unfinished proposal

Discussion of what we learned and how we worked

During the classes.

Organizing time.

Guys, I’m glad to see you in full force, in a good mood and I hope for a fruitful lesson.

Sit down.

Now we will conduct a lesson readiness raid:

show the diaries

show me your pens

show the textbooks

show your notebooks

Everything is ready for the lesson, we can start.

Learning new material

Today we are starting to study the big topic “Coding and processing of text information”, and our first lesson is called “Coding text information”
On the screen is the first slide of a multimedia presentation with the topic of the lesson.

In today's lesson we will get acquainted with text encoding techniques that were invented by people at various stages of the development of human thought, with binary coding of information in a computer, we will learn to determine numeric character codes, enter characters using numeric codes and convert Russian-language text in a text editor.

The problem of information security has worried people for several centuries.

Codes appeared in ancient times in the form of cryptograms (which translated from Greek means “secret writing”). Sometimes sacred Jewish texts were encrypted using the substitution method. Instead of the first letter of the alphabet, the last letter was written, instead of the second, the penultimate one, etc. this ancient cipher was called atbash.

Show slide number 2

Here are several text encoding techniques that were invented at various stages of the development of human thought.

- cryptography- this is secret writing, a system of changing writing in order to make the text incomprehensible to the uninitiated;

- Morse code or an uneven telegraph code, in which each letter or sign is represented by its own combination of short elementary bursts of electric current (dots) and elementary bursts of triple duration (dash);

- sign gestures– sign language used by people with hearing impairments.

Question: What other examples of encoding text information can be given?

Students give examples . ( Viginère cipher, substitution cipher)

Show slide number 3

One of the earliest known encryption methods is named after the Roman emperor Julius Caesar (1st century BC). This method is based on replacing each letter of the encrypted text with another, by shifting the alphabet from the original letter by a fixed number of characters. So the word byte when shifted three characters to the right, it is encoded as a word dgmh . The reverse process of deciphering a given word is necessary to replace each encrypted letter with the third one to the left of it.

Show slide number 4

In Ancient Greece (2nd century BC) a cipher was known that was created using the Polybius square. For encryption, a table was used, which was a square with six columns and six rows, which were numbered from 1 to 6. One letter was written in each cell of such a table. As a result, each letter corresponded to a pair of numbers, and encryption was reduced to replacing the letter with a pair of numbers. The first digit indicates the row number, the second – the column number. The word byte is encoded in this case as follows: 12 11 25 42

Show slide number 5.

Decipher the following phrase using the Polybius square

"33 11 35 36 24 32 16 36 11 45 43 51 24 32 41 63"

Question: What did you get?

Student response: We learn from examples

The answer is compared with the correct answer that appears on slide No. 5.

Binary coding of text information in a computer

Teacher: Information expressed using natural and formal languages in written form is usually called text information.

Show slide number 6.

To represent text information (uppercase, lowercase letters of the Russian and Latin alphabets, numbers, signs and mathematical symbols), 256 different characters are sufficient.

If you add up all the signs:

33 lowercase letters of the Russian alphabet + 33 uppercase letters = 66;

For the Latin alphabet 26 + 26 = 52;

Numbers from 0 to 9

It turns out that you need 127 characters. There are still 129 values left that can be used to indicate punctuation marks, arithmetic marks, service operations (line feed, space, etc.)

Show slide number 7

According to the formula N = 2 I we can calculate how much information is needed to encode each character:

N = 2 I  256 = 2 I  2 8 = 2 I  I= 8 bits

To process text information on a computer, it is necessary to represent it in a binary sign system. We have calculated that encoding each character requires 8 bits of information, i.e. the length of the binary code of the character is eight binary characters. Each character must be assigned a unique binary code from the range from 00000000 to 11111111 (in decimal code from 0 to 255).

When text information is entered into a computer, it is binary encoded. The user presses a sign key on the keyboard, and a certain sequence of eight electrical pulses (binary sign code) is sent to the computer. In the process of displaying on a computer screen, reverse recoding is performed, i.e. converting binary code into its image.

Show slide number 8

Assigning a specific binary code to a character is a matter of convention, which is recorded in the code table. An international agreement has been adopted to assign each character its own unique code. The ASCII code table (American Standard Code for Information Interchange) has been adopted as an international standard.

This table presents codes from 0 to 127 (letters of the English alphabet, symbols of mathematical operations, service symbols, etc.), and codes from 0 to 32 are assigned not to symbols, but to function keys.

Write down the name of this code table and the range of characters to be encoded.

Codes 128 to 255 are allocated to the national standards of each country. This is sufficient for most developed countries.

Several different code table standards have been introduced for Russia (codes 128 to 255).

Show slide number 9.

Here are some of them. Let's look at and write down their names:

KOI - 8 , Windows MS-DOS , Mas, ISO.

There are approximately 6,800 different languages in the world. If you read text printed in Japan on a computer in Russia or the USA, you will not be able to understand it. So that the letters of any country could be read on any computer, two bytes (16 bits) were used to encode them.

Let us also determine the number of characters that can be encoded according to this standard:

N = 2 I = 2 16 = 65536

this number of characters is enough to encode not only the Russian and Latin alphabets, but also Greek, Arabic, Hebrew and other alphabets.

Physical education minute

Now let’s do some physical education: first, use the tip of your nose to write figuratively on the ceiling “I like computer science.”

Exercise for the eyes:

Blink quickly, close your eyes and sit quietly, slowly counting to 5. Repeat 4-5 times.

Extend your right arm forward. Follow with your eyes, without turning your head, the slow movements of the index finger of your outstretched hand to the left and right, up and down. Repeat 4-5 times.

Look at the index finger of your outstretched hand for the count of 1-4, then move your gaze into the distance for the count of 1-6. Repeat 4-5 times.

At an average pace, make 3-4 circular movements with your eyes to the right side, and the same amount to the left side. Relax your eye muscles and look into the distance while counting 1-6. Repeat 1-2 times.

Consolidation of acquired knowledge.

It’s not for nothing that the Roman fabulist Phaedrus said: “Science is the captain, and practice is the soldiers.” Therefore, now let's move from theory to practice.

Open the textbook on page 152, find practical work No. 8, read it.

Write down in your notebook the topic of practical work “Coding text information”, the purpose of the work: to learn how to determine numeric character codes, enter characters using numeric codes and convert Russian-language text in a text editor.

Turn on your computers and we'll get this job done together.

Task No. 1. In the Word text editor, determine the numeric codes of several characters:

in Windows encoding;

in Unicode encoding (Unicode)

Launch Word text editor

enter the command (Insert – Symbol...). The Symbol dialog box will appear on the screen. The central part of the dialog panel is occupied by a table of symbols.

To determine the decimal numeric code of a character in Windows encoding using the drop-down list from: select the encoding type Cyrillic (dec.).

Select a symbol in the symbol table. The character's decimal code appears in the Character Code: text box.

To define a hexadecimal numeric code in Unicode using the drop-down list from: select the Unicode encoding type (hex).

Select a symbol in the symbol table. The hexadecimal numeric code for the character appears in the Character Code: text box.

Using an electronic calculator, convert the hexadecimal numeric code to the decimal number system:

0586 16 = X 10; 1254 16 = X 10; 8569 16 = X 10;

Task No. 2. In the text editor Notepad, enter a sequence of characters in Windows and MS-DOS encodings using numeric codes.

Initial check of understanding

Teacher Questions

1. What principle of encoding text information is used in a computer? (When text information is entered into a computer, it is binary encoded. The user presses a sign key on the keyboard, and a certain sequence of eight electrical pulses (binary sign code) is sent to the computer. In the process of displaying it on the computer screen, reverse recoding is performed, i.e. converting binary code to its image.)

2. What is the name of the international character encoding table?( ASCII(American Standard Code for Information Interchange - American standard code For exchange information )

3. List the names of encoding tables for Russian characters. (KOI - 8, MS - DOS , Mas, ISO , Windows )

The teacher distributes cards with individual tasks. (Petya and Kolya write emails to each other in KOI-8 encoding. One day Petya made a mistake and sent a letter in Windows encoding. Kolya received the letter and, as always, read it in KOI-8. The result was a meaningless text in which the word *** was often repeated ***. What word was in the original text of the letter?

Option 1 – ULBOET (scanner)

Option 2 - RBNSFSH (memory)

Option 3 – RTYOFET (printer)

Option 4 – DYULEFB (floppy disk)

Option 5 – FTELVPM (trackball)

Option 6 – NPOYFPT (monitor)

Option 7 – RTPGEUUPT (processor)

Option 8 – LMBCHYBFHTB (keyboard)

Option 9 – NBFETYOULBS RMBFB (motherboard)

Option 10 – FBLFPCHBS YBUFPFB RTPGEUUPTB (processor clock frequency)

Homework

According to the textbook by N. Ugrinovich, paragraph 3.1. pp. 74 - 77

Encode your first and last name in code KOI - 8. Write the result as:

binary code

decimal code

Additional task (on card): decrypt the text using KOI -8 encoding:

254 212 207 194 205 213 196 210 207 214 201 218 206 216 208 210 207 214 201 212 216, 218 206 193 212 216 206 193 196 207 194 206 207 206 197 205 193 204 207,

228 215 193 215 193 214 206 217 200 208 215 193 215 201 204 193 218 193 208 207 205 206 201 196 204 209 206 193 222 193 204 193:

244 217 204 213 222 219 197 199 207 204 207 196 193 202, 222 197 205 222 212 207 208 207 208 193 204 207 197 211 212 216,

233 204 213 222 219 197 194 213 196 216 207 196 201 206, 222 197 205 215 205 197 211 212 197 21 203 197 205 208 207 208 193 204 207.

(To live your life wisely, you need to know a lot,

Remember two important rules to get started:

You're better off starving than eating crap

Computer science and information technology. Textbook for 8th grade /N.D. Ugrinovich. - M. BINOM. Laboratory of Knowledge, 2011. – 205 pp.: ill.

Journal "Informatics and Education", No. 4, 2003, No. 6, 2006

Computer science 7 – 9 grades. / A.G. Kushnirenko, G.V. Lebedev, Ya.N. Zaidelman, M.: Bustard, 2001. – 336 pp.: ill.

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Slide captions:

04/11/17 Coding of text information

04/11/17 Information expressed using natural and formal languages in written form is called textual information

Historical background Cryptography is a secret writing, a system of changing writing in order to make the text incomprehensible to the uninitiated Morse code or uneven telegraph code, in which each letter or sign is represented by its own combination of short elementary messages of electric current (dots) and elementary messages of triple duration (dash) Sign language is a sign language used by people with hearing impairments

Caesar's Code A B C D E E F G H I J K L M N O P R S T U V H C CH W Q Y Y Y J1 Julius Caesar (1st century BC) Replace each letter of the coded one text to another by shifting the alphabet from the original letter by a fixed number of characters! Let's encode BY T - shift it 2 characters to the right We get: G V L F

Assignment: Decipher the phrase of the Persian poet Jalaleddin Rumi “kgnusm yoogkg fesl - ttfkhya fzuzhschz fhgrzkh yoogksp”, encoded using the Caesar cipher. It is known that each letter of the source text is replaced by the third letter after it. Rumi 1207-1273 A B C D E E F G H H I J K L M N O P R S T U V H C CH W Q Y Y Z Answer: Close your eyes - let your heart become an eye

Binary encoding of text information To encode 1 character, 1 byte of information is used. 1 byte 256 characters 66 letters of the Russian alphabet 52 letters of the English alphabet 0-9 numbers Punctuation marks

When processing text information in a computer, each character is represented by a binary code 1 character 8 bits From 00000000 to 11111111 Assigning a specific binary code to a character is a matter of agreement, which is recorded in the code table

ASCII code table A merican Standard C ode for I nformation Interchange codes from 0 to 32 function keys codes from 33 to 127 letters of the English alphabet, symbols of mathematical operations, punctuation marks

Encoding tables for Russian-language characters KOI-8 MAC ISO

Unicode encoding 1 character - 2 bytes (16 bits), which can encode 65,536 characters

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