Presentation on computer science "coding and processing of text information." Coding of text information Amount of information in a message

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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 electric current(dots) and elementary messages of triple duration (dash) Signature gestures - 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

On the topic: methodological developments, presentations and notes

Alphabetical approach to determining the amount of information. Units of information measurement. Encoding text information

First lesson in 8th grade. Notes and homework....

"Encoding of text information. Encodings of the Russian alphabet." Practical work “Coding text information”.

Lesson summary “Coding text information. Encodings of the Russian alphabet" is intended for computer science teachers teaching in 8th grade. The lesson is divided into two stages. The first one provides for study...

Processing of text information. Entering text in the WordPad word processor.

Outline open lesson for studying the WordPad word processor. Offered to help computer science and ICT teachers when studying the topic “Text Information Processing” in fifth grade. P...

Outline of an open lesson in computer science.

Topic “Coding text information” 8th grade.

Goals:

Introduce students to ways of encoding information in a computer;

Consider examples of problem solving;

To promote the development of students' cognitive interests.

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

Tasks:

To form students’ knowledge on the topic “Coding text (symbolic) information”;

To promote the formation of imaginative thinking in schoolchildren;

Develop skills of analysis and self-analysis;

Develop the ability to plan your activities.

Lesson progress:

Organizational moment(1 minute)

Checking the availability of students.

Announcing the topic of the lesson (4 minutes)

The first slide of the presentation with the words “Lesson topic”. There is no topic title. Students are asked to name the topic themselves, using words encrypted in puzzles:

Explanation of new material (25 minutes).

The teacher introduces children to the concept of Cryptography, talks about one of the first ciphers - the Caesar Cipher, thus making an interdisciplinary connection with the history lessons of the Ancient World.

Then schoolchildren are given a task on encoding (decoding) text information using the Caesar cipher.

The task is duplicated on the slide and in the handouts (Appendix 1).

The connection with history continues when explaining to children another way of encoding text information - Morse code.

Then the teacher, drawing attention to the fact that Morse code uses TWO symbols (a dot and a dash), leads to the modern method of encoding text on a computer - binary encoding.

An important component of the lesson when studying the topic “Coding text information” is to teach schoolchildren to solve problems to determine the information volume of a text message. Thus, the final stage of the stage of explaining new material is an example of solving a similar problem.

Consolidation of the studied material (10 minutes).

Students are asked to solve problems on their own, similar to the one just discussed. Task No. 3 is a task with increased complexity, which involves not only the application of newly acquired knowledge, but also the ability to find the main conditions of the task, cutting off secondary and unimportant information.

The text of the assignments is duplicated on the presentation slide and in the handouts (Appendix 1).

Lesson summary. Homework. (5 minutes)

Students talk about the topic of the lesson, the knowledge they received today, and the difficulties they encountered in solving tasks. The most active students receive grades. The teacher assigns homework: notes in a notebook, assignment on a card (Appendix 2)

Appendix 1.

Handouts for the lesson

Decipher the phrase of the Persian poet Jalaluddin Rumi "kgnusm yoogkg fesl ttsfhya fzuzhschz fhgrzkh yoogksp", encoded in Caesar's code

A B C D E F G H H I J J K L M N O P R S T U V X C

Condition: Determine the information volume of a phrase

Optimism is a lack of information.(Text is written in ASCII format.)

Task 1.

The ASCII text contains 2 pages of 64 lines, each with 32 characters. Find the information volume of the text.

Task 2.

The text in Unicode format (16 bits per character) looks like this: “If you want to conquer the whole world, then defeat yourself. F.M. Dostoevsky" Determine the information volume of the phrase. (Ignore quotes)

Problem 3.*

There are 16 letters in the alphabet of the Tumbu-Yumbu tribe. The constitution of 128 pages of laws and regulations is written in this language. Each page is 256 colorful and pompous lines about the equality of people before dinner and before the Law. Lines always start with capital letter, and there are 32 letters in total. What size flash drive does a tribal leader need to have to store the Tumboyumba Constitution?

P.S. The letters are different, remember this, otherwise you will end up as the main course for lunch.

Appendix 2.

Homework assignment.

The Unicode text file contains 100 sheets of 64 lines, 32 characters each. What is the information volume of the file?

The text file in KOI-8 encoding contains 128 sheets of 64 lines, 32 characters each. It is transmitted in 4 minutes. What is the speed of the connection over which the file is transferred?

Piyaeva Olga Nikolaevna

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

Job title: computer science 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 methods 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, a sense 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 program, 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 min

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 the teacher’s questions, completing a decoding task

information

Physical education minute

2 min.

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

Execute independent work

Homework

2 min.

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

Progress of the lesson.

Organizational moment.

Guys, I’m glad to see you in full force, in 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 me 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”
First slide on screen 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 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 particular 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. As international standard ASCII code table has been adopted (American Standard Code for Information Interchange - American standard code for information exchange)

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 for national standards 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.

View at index finger with an outstretched arm 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.

No wonder 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 the topic in your notebook practical work“Coding text information”, the goal 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 determine the hexadecimal numeric code in the Unicode encoding, use 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 to each other emails in KOI encoding - 8. 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.