IELTS® Academic Reading Practice 81

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Information theory (“Matching Information” Strategy Video Included)

Information theory lies at the heart of everything - from DVD players and the genetic code of DNA to the physics of the universe at its most fundamental. It has been central to the development of the science of communication, which enables data to be sent electronically and has therefore had a major impact on our lives.

A In April 2002 an event took place which demonstrated one of the many applications of information theory. The space probe, Voyager I, launched in 1977, had sent back spectacular images of Jupiter and Saturn and then soared out of the Solar System on a one-way mission to the stars. After 25 years of exposure to the freezing temperatures of deep space, the probe was beginning to show its age. Sensors and circuits were on the brink of failing and NASA experts realised that they had to do something or lose contact with their probe forever. The solution was to get a message to Voyager I to instruct it to use spares to change the failing parts. With the probe 12 billion kilometres from Earth, this was not an easy task. By means of a radio dish belonging to NASA's Deep Space Network, the message was sent out into the depths of space. Even travelling at the speed of light, it took over 11 hours to reach its target, far beyond the orbit of Pluto. Yet, incredibly, the little probe managed to hear the faint call from its home planet, and successfully made the switchover.

B It was the longest-distance repair job in history, and a triumph for the NASA engineers. But it also highlighted the astonishing power of the techniques developed by American communications engineer Claude Shannon, who had died just a year earlier. Born in 1916 in Petoskey, Michigan, Shannon showed an early talent for maths and for building gadgets, and made breakthroughs in the foundations of computer technology when still a student. While at Bell Laboratories, Shannon developed information theory, but shunned the resulting acclaim. In the 1940s, he single-handedly created an entire science of communication which has since inveigled its way into a host of applications, from DVDs to satellite communications to bar codes - any area, in short, where data has to be conveyed rapidly yet accurately.

C This all seems light years away from the down-to-earth uses Shannon originally had for his work, which began when he was a 22-year-old graduate engineering student at the prestigious Massachusetts Institute of Technology in 1939. He set out with an apparently simple aim: to pin down the precise meaning of the concept of 'information'. The most basic form of information, Shannon argued, is whether something is true or false - which can be captured in the binary unit, or 'bit', of the form 1 or 0. Having identified this fundamental unit, Shannon set about defining otherwise vague ideas about information and how to transmit it from place to place. In the process he discovered something surprising: it is always possible to guarantee information will get through random interference - 'noise' - intact.

D Noise usually means unwanted sounds which interfere with genuine information. Information theory generalises this idea via theorems that capture the effects of noise with mathematical precision. In particular, Shannon showed that noise sets a limit on the rate at which information can pass along communication channels while remaining error-free. This rate depends on the relative strengths of the signal and noise travelling down the communication channel, and on its capacity (its 'bandwidth'). The resulting limit, given in units of bits per second, is the absolute maximum rate of error-free communication given signal strength and noise level. The trick, Shannon showed, is to find ways of packaging up - 'coding' - information to cope with the ravages of noise, while staying within the information-carrying capacity - 'bandwidth' - of the communication system being used.

E Over the years scientists have devised many such coding methods, and they have proved crucial in many technological feats. The Voyager spacecraft transmitted data using codes which added one extra bit for every single bit of information; the result was an error rate of just one bit in 10,000 - and stunningly clear pictures of the planets. Other codes have become part of everyday life - such as the Universal Product Code, or bar code, which uses a simple error-detecting system that ensures supermarket check-out lasers can read the price even on, say, a crumpled bag of crisps. As recently as 1993, engineers made a major breakthrough by discovering so-called turbo codes - which come very close to Shannon's ultimate limit for the maximum rate that data can be transmitted reliably, and now play a key role in the mobile videophone revolution.

F Shannon also laid the foundations of more efficient ways of storing information, by stripping out superfluous ('redundant') bits from data which contributed little real information. As mobile phone text messages like 'I CN C U' show, it is often possible to leave out a lot of data without losing much meaning. As with error correction, however, there's a limit beyond which messages become too ambiguous. Shannon showed how to calculate this limit, opening the way to the design of compression methods that cram maximum information into the minimum space.

 
27. An explanation of the factors affecting the transfer of information: D. In this paragraph, you'll see the following phrases: "interferes with genuine information", "information can pass along communication channels", and "depends on the relative strength of the signal". Although the word "affects" is used in the information, "interferes" is similar, albeit a more specific term. "Pass along" is another way to say "transmission", and "depends on" is a way to discuss what affects something. Thus, Paragraph D contains information regarding: An explanation of the factors affecting the transfer of information.
 
28. an example of how unnecessary information can be omitted: F. In this paragraph, you'll see the following phrases: "stripping out superfluous ('redundant') bits" and "leave out a lot of data without losing much meaning". "Stripping out" and "leave out" are phrasal verbs used to convey the idea of "omit" and "superfluous" and "redundant" are ways to say "unnecessary". Thus, Paragraph F contains information regarding: An example of how unnecessary information can be omitted.
 
29. A reference to Shannon's attitude to fame: B. First off, it is best to scan for the name "Shannon" in order to find the correct paragraph quickly. With a brief scan, you'll see that Shannon is mentioned in paragraphs B, C, D, and F. Now, you need to scan these paragraphs to find his reaction to claim. In Paragraph B, you'll see the following phrase: "shunned the resulting acclaim". This is a short phrase that shows his reaction to celebrity. Thus, Paragraph B contains information regarding: A reference to Shannon's attitude to fame.
 
30. details of a machine capable of interpreting incomplete information: E. In this paragraph, you'll see the following phrases: "error-detecting system that ensures supermarket check-out lasers can read the price on say, even a crumpled bag of crisps", and "transmitted reliably". The fact that the paragraph uses the word "crumpled" conveys the idea that these systems can understand difficult codes and situations, and thus incomplete information. Therefore, Paragraph E contains information regarding: details of a machine capable of interpreting incomplete information.
 
31. a detailed account of an incident involving information theory: A. In this paragraph, you'll see the following phrases: "In April 2002 an event took place which demonstrated one of the many applications of information theory". It further goes on to explain this theory in detail, which satisfies the requirement of the question. Thus, Paragraph A contains information regarding a detailed account of an incident involving information theory.
 
32. a reference to what Shannon initially intended to achieve in his research: C. In this paragraph, you'll see the following phrases: "the down-to-earth uses Shannon originally had for his work" and "he set out on an apparently simple aim". The words "originally" and "set out" are ways to describe the initial intentions of Shannon's work. Thus, Paragraph C contains information regarding a reference to what Shannon initially intended to achieve in his research.



This reading practice simulates the Matching Information question type of the IELTS Academic Reading test. Read the passage and answer questions 27-32.
Questions 27-32
The reading passage has six paragraphs labelled A-F.

Which paragraph contains the following information?

Write the correct letter A-F in boxes 27-32 on your answer sheet.

NB You may use any letter more than once.

27. an explanation of the factors affecting the transmission of information

28. an example of how unnecessary information can be omitted

29. a reference to attitude to fame

30. details of a machine capable of interpreting incomplete information

31. a detailed account of an incident involving information theory

32. a reference to what Shannon initially intended to achieve in his research




Answer Sheet
1
N/A
2
N/A
3
N/A
4
N/A
5
N/A
6
N/A
7
N/A
8
N/A
9
N/A
10
N/A
11
N/A
12
N/A
13
N/A
14
N/A
15
N/A
16
N/A
17
N/A
18
N/A
19
N/A
20
N/A
21
N/A
22
N/A
23
N/A
24
N/A
25
N/A
26
N/A
27
28
29
30
31
32
33
N/A
34
N/A
35
N/A
36
N/A
37
N/A
38
N/A
39
N/A
40
N/A


Reading Passage Vocabulary
Information theory (“Matching Information” Strategy Video Included)


Information theory lies at the heart of everything - from DVD players and the genetic code of DNA to the physics of the universe at its most fundamental. It has been central to the development of the science of communication, which enables data to be sent electronically and has therefore had a major impact on our lives.

A In April 2002 an event took place which demonstrated one of the many applications of information theory. The space probe, Voyager I, launched in 1977, had sent back spectacular images of Jupiter and Saturn and then soared out of the Solar System on a one-way mission to the stars. After 25 years of exposure to the freezing temperatures of deep space, the probe was beginning to show its age. Sensors and circuits were on the brink of failing and NASA experts realised that they had to do something or lose contact with their probe forever. The solution was to get a message to Voyager I to instruct it to use spares to change the failing parts. With the probe 12 billion kilometres from Earth, this was not an easy task. By means of a radio dish belonging to NASA's Deep Space Network, the message was sent out into the depths of space. Even travelling at the speed of light, it took over 11 hours to reach its target, far beyond the orbit of Pluto. Yet, incredibly, the little probe managed to hear the faint call from its home planet, and successfully made the switchover.

B It was the longest-distance repair job in history, and a triumph for the NASA engineers. But it also highlighted the astonishing power of the techniques developed by American communications engineer Claude Shannon, who had died just a year earlier. Born in 1916 in Petoskey, Michigan, Shannon showed an early talent for maths and for building gadgets, and made breakthroughs in the foundations of computer technology when still a student. While at Bell Laboratories, Shannon developed information theory, but shunned the resulting acclaim. In the 1940s, he single-handedly created an entire science of communication which has since inveigled its way into a host of applications, from DVDs to satellite communications to bar codes - any area, in short, where data has to be conveyed rapidly yet accurately.

C This all seems light years away from the down-to-earth uses Shannon originally had for his work, which began when he was a 22-year-old graduate engineering student at the prestigious Massachusetts Institute of Technology in 1939. He set out with an apparently simple aim: to pin down the precise meaning of the concept of 'information'. The most basic form of information, Shannon argued, is whether something is true or false - which can be captured in the binary unit, or 'bit', of the form 1 or 0. Having identified this fundamental unit, Shannon set about defining otherwise vague ideas about information and how to transmit it from place to place. In the process he discovered something surprising: it is always possible to guarantee information will get through random interference - 'noise' - intact.

D Noise usually means unwanted sounds which interfere with genuine information. Information theory generalises this idea via theorems that capture the effects of noise with mathematical precision. In particular, Shannon showed that noise sets a limit on the rate at which information can pass along communication channels while remaining error-free. This rate depends on the relative strengths of the signal and noise travelling down the communication channel, and on its capacity (its 'bandwidth'). The resulting limit, given in units of bits per second, is the absolute maximum rate of error-free communication given signal strength and noise level. The trick, Shannon showed, is to find ways of packaging up - 'coding' - information to cope with the ravages of noise, while staying within the information-carrying capacity - 'bandwidth' - of the communication system being used.

E Over the years scientists have devised many such coding methods, and they have proved crucial in many technological feats. The Voyager spacecraft transmitted data using codes which added one extra bit for every single bit of information; the result was an error rate of just one bit in 10,000 - and stunningly clear pictures of the planets. Other codes have become part of everyday life - such as the Universal Product Code, or bar code, which uses a simple error-detecting system that ensures supermarket check-out lasers can read the price even on, say, a crumpled bag of crisps. As recently as 1993, engineers made a major breakthrough by discovering so-called turbo codes - which come very close to Shannon's ultimate limit for the maximum rate that data can be transmitted reliably, and now play a key role in the mobile videophone revolution.

F Shannon also laid the foundations of more efficient ways of storing information, by stripping out superfluous ('redundant') bits from data which contributed little real information. As mobile phone text messages like 'I CN C U' show, it is often possible to leave out a lot of data without losing much meaning. As with error correction, however, there's a limit beyond which messages become too ambiguous. Shannon showed how to calculate this limit, opening the way to the design of compression methods that cram maximum information into the minimum space.

 
27. An explanation of the factors affecting the transfer of information: D. In this paragraph, you'll see the following phrases: "interferes with genuine information", "information can pass along communication channels", and "depends on the relative strength of the signal". Although the word "affects" is used in the information, "interferes" is similar, albeit a more specific term. "Pass along" is another way to say "transmission", and "depends on" is a way to discuss what affects something. Thus, Paragraph D contains information regarding: An explanation of the factors affecting the transfer of information.
 
28. an example of how unnecessary information can be omitted: F. In this paragraph, you'll see the following phrases: "stripping out superfluous ('redundant') bits" and "leave out a lot of data without losing much meaning". "Stripping out" and "leave out" are phrasal verbs used to convey the idea of "omit" and "superfluous" and "redundant" are ways to say "unnecessary". Thus, Paragraph F contains information regarding: An example of how unnecessary information can be omitted.
 
29. A reference to Shannon's attitude to fame: B. First off, it is best to scan for the name "Shannon" in order to find the correct paragraph quickly. With a brief scan, you'll see that Shannon is mentioned in paragraphs B, C, D, and F. Now, you need to scan these paragraphs to find his reaction to claim. In Paragraph B, you'll see the following phrase: "shunned the resulting acclaim". This is a short phrase that shows his reaction to celebrity. Thus, Paragraph B contains information regarding: A reference to Shannon's attitude to fame.
 
30. details of a machine capable of interpreting incomplete information: E. In this paragraph, you'll see the following phrases: "error-detecting system that ensures supermarket check-out lasers can read the price on say, even a crumpled bag of crisps", and "transmitted reliably". The fact that the paragraph uses the word "crumpled" conveys the idea that these systems can understand difficult codes and situations, and thus incomplete information. Therefore, Paragraph E contains information regarding: details of a machine capable of interpreting incomplete information.
 
31. a detailed account of an incident involving information theory: A. In this paragraph, you'll see the following phrases: "In April 2002 an event took place which demonstrated one of the many applications of information theory". It further goes on to explain this theory in detail, which satisfies the requirement of the question. Thus, Paragraph A contains information regarding a detailed account of an incident involving information theory.
 
32. a reference to what Shannon initially intended to achieve in his research: C. In this paragraph, you'll see the following phrases: "the down-to-earth uses Shannon originally had for his work" and "he set out on an apparently simple aim". The words "originally" and "set out" are ways to describe the initial intentions of Shannon's work. Thus, Paragraph C contains information regarding a reference to what Shannon initially intended to achieve in his research.
 
Video Answer Explanation

IELTS Academic Reading Tips for Success
These are general tips that will appear on all reading questions.

Tips to improve your reading speed
To get a high score on the IELTS reading section, you need to have a fast reading speed. To have a fast reading speed, you need to improve your vocabulary and practice dissecting sentences. One strategy to dissect a sentence is to look for the subject and verb of the sentence. Finding the subject and verb will help you better understand the main idea of said sentence. Keep in mind, a common feature of a IELTS reading passage is to join strings of ideas to form long compound sentences. This produces large chunks that students have a hard time absorbing. Do not get overwhelmed by its length, just look for the subject and verb, the rest of the ideas will flow.


Keep in mind, having a slow reading speed makes skimming or scanning a reading passage more difficult. The process of quickly skimming through a reading passage for specific keywords or main ideas is a requirement for you to employ successful reading strategies to improve your IELTS reading score. In other words, skimming and scanning are critical skills to ensure you complete all questions in the allotted time frame.
IELTS Reading Strategies
Once you can read and comprehend a passage with a rate of, at least, 220 words per minute, you'll be ready to start implementing our strategies. All too often, students spend too much time reading the passages and not enough time answering the questions. Here is a step by step guide for tackling the reading section.

  1. Step 1: Read questions first

    One of the most common mistakes that candidates make when approaching the reading exam is reading every single word of the passages. Although you can practice for the exam by reading for pleasure, "reading blindly" (reading without any sense of what the questions will ask) will not do you any favors in the exam. Instead, it will hurt your chances for effectively managing your time and getting the best score.

    The main reason to read the questions first is because the type of question may determine what you read in the passage or how you read it. For example, some question types will call for the "skimming" technique, while others may call for the "scanning" technique.

    It is important to answer a set of questions that are of the same question type. You'll need to determine which question type you want to tackle first. A good strategy would be to start with the easier question type and move on to more difficult question types later. The Easiest question types are the ones where you spend less time reading. For example, the Matching Heading question type is an easier one because you only need to find the heading that best describes the main idea of a paragraph. An example of a difficult question type would be Identifying Information. For this question type, you'll need to read each paragraph to find out if each statement is TRUE, FALSE, or NOT GIVEN according to the passage.

    Here is a table that lists the difficulty levels for each question type. Use this table as a reference when choosing which question type you want to tackle first.


    Difficulty level Question Type
    Easy Sentence Completion
    Short answer
    Medium Matching Features
    Multiple choice
    Matching Headings
    Summary, Table, Flow-Chart Completion
    Difficult Matching Sentence Endings
    Matching Information
    Identifying Information (TRUE/FALSE/NOT GIVEN)
    Identifying Viewer's claims (YES/NO/NOT GIVEN)

  2. Step 2: Read for an objective

    After you've read the questions for the passage, you will be able to read for an objective. What does this mean? For example, if you come across a question that includes the year "1896", you can make a note of when this year comes up in the text, using it to answer the question later on. There are two reading techniques that will help you stay on track with reading for an objective. The first one, skimming, is best defined as reading fast in order to get the "gist", or general idea, or a passage. With this technique, you are not stopping for any unfamiliar words or looking for specific details. The second technique, scanning, is best defined as reading for specific information. With this technique, you are not reading for the overall gist, but rather, specific information. Notice how each of these techniques has a specific objective in mind. This will help you find information more quickly.

  3. Step 3: Take notes

    As you're reading for an objective, you should also be making notes on the margins of the passage, placing stars next to key information, or underlining things that you believe will help you answer the various questions. This will make it easier for you to check back when you are asked certain things in the questions. Choose whichever note-taking system is right for you - just make sure you do it!

  4. Step 4: Answer wisely

    After you've read the questions, read the passage, and have taken any appropriate notes, you you should have located the part of the text where you where you need to read carefully. Then just read carefully and think critically to determine the correct answer.

IELTS Reading Question Types
 
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