Задание 3. Заполните данные определения правильной формой глагола в скобках.

• A gateway is an interface (enable) dissimilar networks to communicate.

• A bridge is a hardware and software combination (use) to connect the same type of networks.

• A backbone is a network transmission path (handle) major data traffic.

• A router is a special computer (direct) messages when several networks are linked.

• A network is a number of computers and peripherals (link) together.

• A LAN is a network (connect) computers over a small distance such as within a company.

• A server is a powerful computer (store) many programs (share) by all the clients in the network.

• A client is a network computer (use) for accessing a service on a server.

• A thin client is a simple computer (comprise) a processor and memory, display, keyboard, mouse and hard drives only.

• A hub is an electronic device (connect) all the data cabling in a network.

LESSON 20

Security — Is Your Privacy Protected?

Task  1. Read and translate the text:

Задание 1. Прочитайте и переведите текст:

    Another key concern is confidentiality. For example, your email message should be seen only by your intended recipient. While the letter is in transit, however, a clever and possibly unscrupulous person or group could intercept or monitor your correspondence. To protect messages, some people use e-mail software products to scramble their letter's sensitive contents before mailing it. At the other end, the receiving party may need similar software for unscrambling the message. Recently, much discussion has focused on the exchange of credit-card and other sensitive information for commercial use on the Internet. Although substantial innovations are expected to strengthen security, the noted American computer security analyst Dorothy Denning states: "Completely secure systems are not possible, but the risk can be reduced considerably, probably to a level commensurate with the value of the information stored on the systems and the threat posed by both hackers and insiders. Absolute security is not realizable in any computer system, whether connected to the Internet or not.

Task  2. Answer the following questions:

Задание 2. Ответьте на следующие вопросы:

1.)  Is security protection important for keeping your privacy?

2.) Read the text “Security — Is Your Privacy Protected?” and discuss the following questions in group:

3) Do you think your information is protected when you use the Internet? Is it safe to share confident information through the Internet? Share your opinion with your groupmates.

4) Choose any topics you like on the given problem ”Internet” and discuss it in group.

Task3. Write a composition giving your own opinion on the topic “The World Wide Web”.

Task  4. Read the rest of this text to find the answers to these questions:

1. Into what two components is the data stream split?

2. What information does an Intra frame contain?

3. What is stored in the P-frames following an I- frame?

4. What is stored in a P-frame in the case of a bouncing ball?

5. What gives the massive reduction in the amount of information needed to reproduce a video sequence?

6. Why is a new l-frame used after a few P- frames?

7. What is stored in a B-frame?

8. Why do В-frames not propagate errors?

    The most common system for the compression of video is MPEG. It works like this. The single data stream off the CD-ROM is split into video and audio components, which are then decompressed s using separate algorithms. The video is processed to produce individual frames as follows. Imagine a sequence of frames depicting a bouncing ball on a plain background. The very first is called an Intra Frame (I-frame). I-frames are compressed using only information in the picture itself just like conventional bitmap compression techniques like JPEG.

    Following I-frames will be one or more predicted frames (P-frames). The difference between the P- is frame and the I-frame it is based on is the only data that is stored for this P-frame. For example, in the case of a bouncing ball, the P picture is stored simply as a description of how the position of the ball has changed from the previous I-frame. Го This takes up a fraction of the space that would be used if you stored the P-frame as a picture in its own right. Shape or colour changes are also stored in the P-frame. The next P-frame may also be based on this P-frame and so on. Storing differences between the frames gives the massive reduction in the amount of information needed to reproduce the sequence. Only a few P-frames are allowed before a new I-frame is introduced into the sequence as a new reference point, since a in small margin of error creeps in with each P-frame.

    Between I and P-frames are bi-directional frames (В-frames), based on the nearest I or P-frames both before and after them. In our bouncing ball example, in a В-frame the picture is stored as the difference between the previous I or P-frame and the В-frame and as the difference between the B- frame and the following I or P-frame. To recreate the В-frame when playing back the sequence, the MPEG algorithm uses a combination of two references. There may be a number of B-frames between I or P-frames. No other frame is ever based on a В-frame so they don’t propagate errors like P-frames.

    Typically, you will have two or three Bs between Is or Ps, and perhaps three to five P-frames between is.

Task  5. Mark the following statements as True or False:

Задание 5. Отметьте следующие утверждения как Истина или Ложь:

1. JPEG is the most common compression system used for video.

2. P-frames only store the changes in the image.

3. There is always at least one P-frame between two I-frames.

4. В-frames store the complete picture information.

5. There can only be one В-frame between each I and P-frame.

6. There are typically about four P-frames between each I-frame.

LESSON 21

Science and Technology

Task  1. Read and translate the text:

Задание 1. Прочитайте и переведите текст:

In recent years, scientific and technological developments have drastically changed life on our planet as well as our views both of us as individuals in society and of the Universe as a whole.

Today, science and technology are closely related. Many modem technologies such as nuclear power and space flights depend on science and the application of scientific knowledge and principles. Each advance in pure science creates new opportunities for the development of new ways of making things to be used in daily life. In turn, technology provides science with new and more accurate instruments for its investigation and research. Technology refers to the ways in which people use discoveries to satisfy needs and desires, to alter the environment, to improve their lives. Throughout human history, men and women have invented tools, machines, materials and techniques, to make their lives easier.

Of course, when we speak of technology today, we are looking at it in a much narrower sense. Generally, we mean industrial technology, or the technology that began about 200 years ago with the development of power-driven machines, growth of the factory system, and mass production of goods that has created the basis for our modern society. Today we often say that we live in an age of science and technology. According to one estimate, 90 % of all the scientists who ever lived, were alive and active in the 1970-s. This increased scientific activity has brought new ideas, processes, and inventions in ever-growing amount. The scientific revolution that started in the 16th century was the first time that science and technology began to work together. Thus, Galileo who made revolutionary discoveries in astronomy and physics also built an improved telescope and patented a system of lifting water. However, it was not until the 19th century that technology truly was based on science and inventors began to build on the work of scientists. For example, Thomas Edison built on the early experiments of Faraday and Henry in his invention of the first practical system of electrical lighting. Edison carried on his investigations until he found the carbon filament for the electric bulb in a research laboratory. This was the first true modern technological research. In a sense, the history of science and technology is the history of all humankind.

Task  2. Answer the following questions:

Задание 2. Ответьте на следующие вопросы:

1. What role has scientific and technological developments played in human's life?

2. What proves that science and technology are closely related today?

Task  3. Read the text “Science and Technology” and discuss the following questions in group:

a) What does the term «technology» refer to?

b) What does the term «industrial technology» mean?

c) How is scientific activity in the 1970s estimated?

d) What facts prove that the scientific revolution in the 16thcentury was the time that science and technology began to work together?