Exam Time for IT. Ч.2. Практикум

assumed to indicate the likelihood of the relevance of that item. One simple consequence of this difference is that DR is more sensitive to error in the sense that, an error in matching will not retrieve the wanted item which implies a total failure of the system. In IR small errors in matching generally do not affect performance of the system significantly.

An information retrieval process begins when a user enters a query into the system. Queries are formal statements of information needs, for example search strings in web search engines. In information retrieval a query does not uniquely identify a single object in the collection. Instead, several objects may match the query, perhaps with different degrees of relevancy.

An object is an entity which keeps or stores information in a database. User queries are matched to objects stored in the database. Depending on the application the data objects may be, for example, text documents, images or videos. Often the documents themselves are not kept or stored directly in the IR system, but are instead represented in the system by document surrogates.

Most IR systems compute a numeric score on how well each object in the database matches the query, and rank the objects according to this value. The top ranking objects are then shown to the user. The process may then be iterated if the user wishes to refine the query.

The diagram shows the three components: input, processor and output. Such a trichotomy may seem a little trite, but the components constitute a convenient set of pegs upon which to hang a discussion.

Starting with the input side of things, the main problem here is to obtain a representation of each document and query suitable for a computer to use. Let us emphasize that most computerbased retrieval systems store only a representation of the document (or query) which means that the text of a document is lost once it has been processed for the purpose of generating its representation. A document representative could, for example, be a list of extracted words considered to be significant. Rather than have the computer process the natural language, an alternative approach is to have an artificial language within which all queries and documents can be formulated. There is some evidence to show that this can be effective. Of course it presupposes that a user is willing to be taught to express his information need in the language.

When the retrieval system is on-line, it is possible for the user to change his request during one search session in the light of a sample retrieval, thereby, it is hoped, improving the subsequent retrieval run. Such a procedure is commonly referred to as feedback. An example of a sophisticated on-line retrieval system is the MEDLINE system. It is fair to say that it will be only a short time before all retrieval systems will be on-line.

Secondly, the processor, that part of the retrieval system concerned with the retrieval process. The process may involve structuring the information in some appropriate way, such as classifying it. It will also involve performing the actual retrieval function, that is, executing the search strategy in response to a query.

Finally, we come to the output, which is usually a set of citations or document numbers. In an operational system the story ends here. However, in an experimental system it leaves the evaluation to be done. Much of the research and development in information retrieval is aimed at

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improving the effectiveness and efficiency of retrieval. Efficiency is usually measured in terms of the computer resources used such as core, backing store, and C.P.U. time. It is difficult to measure efficiency in a machine independent way. In any case, it should be measured in conjunction with effectiveness to obtain some idea of the benefit in terms of unit cost.

Questions for self-check:

Why is information retrieval considered to be a wide, often loosely-defined term?

Which properties of data and information retrieval make the difference between them clear? Analyze each point of difference.

What does a query represent and is required for?

What keeps or stores information in a database? Give some examples.

How do most IR systems function for the top ranking objects to be shown to the user?

What are the components that constitute the trichotomy? Give brief characteristics of each part.

What are the benefits of an on-line retrieval system?

Exercises:

1. Give English-Russian equivalents of the following words and expressions:

2.Find the word belonging to the given synonymic group among the words and word combinations from the previous exercise:

a)size, amount, degree, level, scope;

b)specify, make more exact/precise/accurate, itemize, work out in detail;

c)unit, thing, object, matter;

d)repeat, review, follow;

e)coincidence, combining, matching, overlay, stacking;

f)replace with, exchange, use instead;

g)stale, banal, commonplace, unoriginal;

h)substitute, replacement, stand-in, deputy;

i)element, character, cell;

j)core, pivot, stem, bar;

k)conclusion, deduction, supposition, assumption, suggestion.

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Topic 8. Cybersecurity

People have worried about the security of their computers for many years, and computer security concerns have always been a significant factor in the development and application of computer technology throughout society.

In the early development of computers, security was a strong factor – the computations that motivated their development had military applications. But the computers themselves were so big and so few that they were relatively easy to protect simply by limiting physical access to them to their programmers and operators. Today, computers have shrunk so that a web server can be hidden in a matchbox and have become so common that few people can give an accurate count of the number they have in their homes and automobiles. Computers constantly communicate with one another; an isolated computer is crippled.

Today computer security refers to the branch of computer technology that deals with preventing and detecting unauthorized use of your computer.

Prevention measures help you to stop unauthorized users (also known as intruders) from accessing any part of your computer system. Detection helps accurate count of the number they have in ther homes and automobiles. Computers constantly communicate with one another; an isolated computer is crippled. The meaning and implications of computer security have changed over the years as well.

Today computer security refers to the branch of computer technology that deals with preventing and detecting unauthorized use of your computer. Prevention measures help you to stop unauthorized users.

The objective of computer security includes protection of information and property from theft, corruption, or natural disaster while allowing the information and property to remain accessible and productive to its intended users.

The term computer system security means the collective processes and mechanism by which sensitive and valuable information and services are protected from publication, tampering or collapse by unauthorized activities or untrustworthy individuals and unplanned events respectively. The strategies and methodologies of computer security often differ from most other computer technologies because of its somewhat elusive objective of preventing unwanted computer behavior instead of enabling wanted computer behavior.

The major technical areas of computer security are usually represented by the initials CIA: confidentiality, integrity, and availability or authentication.

Confidentiality means that information cannot be accessed by unauthorized parties. Confidentiality is also known as secrecy; breaches of confidentiality range from the embarrassing to the disastrous. The need for keeping information secret arises from the use of computers in sensitive fields such as government and industry. For example, military and civilian institutions in the government often restrict access to information to those who need that information.

Integrity refers to the trustworthiness of data or resources, and it is usually phrased in terms of preventing improper or unauthorized change. Integrity means that information is protected against unauthorized change that is not detectable to authorized users; many incidents of hacking compromise the integrity of databases and other resources.

Availability refers to the ability to use the information or resource desired. Availability is an important aspect of reliability as well as of system design because an unavailable system is at least as bad as no system at all.

Computer crimes.

More and more, the operations of our businesses, governments, and financial institutions are controlled by information that exists only inside computer memories. Anyone clever enough to modify this information for his own purposes can reap substantial rewards. Even worse, a number of people who have done this and been caught at it have managed to get away without punishment.

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These facts have not been lost on criminals or would-be criminals. A recent Stanford Research Institute study of computer abuse was based on 160 case histories, which probably are just the proverbial tip of the iceberg. After all, we only know about the unsuccessful crimes. How many successful ones have gone undetected is anybody's guess.

Here are a few areas in which computer criminals have found the pickings all too easy. Banking. All but the smallest banks now keep their accounts on computer files. Someone who

knows how to change the numbers in the files can transfer funds at will. For instance, one programmer was caught having the computer transfer funds from other people's accounts to his wife's checking account. Often, tradition ally trained auditors don't know enough about the workings of computers to catch what is taking place right under their noses.

Business. A company that uses computers extensively offers many opportunities to both dishonest employees and clever outsiders. For instance, a thief can have the computer ship the company's products to addresses of his own choosing. Or he can have it issue checks to him or his confederates for imaginary supplies or services. People have been caught doing both.

Credit Cards. There is a trend toward using cards similar to credit cards to gain access to funds through cash-dispensing terminals. Yet, in the past, organized crime has used stolen or counterfeit credit cards to finance its operations. Banks that offer after-hours or remote banking through cashdispensing terminals may find themselves unwillingly subsidizing organized crime.

Theft of Information. Much personal information about individuals is now stored in computer files. An unauthorized person with access to this information could use it for blackmail. Also, confidential information about a company's products or operations can be stolen and sold to unscrupulous competitors. (One attempt at the latter came to light when the competitor turned out to be scrupulous and turned in the people who were trying to sell him stolen information.)

Software Theft. The software for a computer system is often more expensive than the hardware. Yet this expensive software is all too easy to copy. Crooked computer experts have devised a variety of tricks for getting these expensive programs printed out, punched on cards, recorded on tape, or otherwise delivered into their hands. This crime has even been perpetrated from remote terminals that access the computer over the telephone.

Theft of Time-Sharing Services. When the public is given access to a system, some members of the public often discover how to use the system in unauthorized ways. For example, there are the "phone freakers" who avoid long distance telephone charges by sending over their phones control signals that are identical to those used by the telephone company. Since time-sharing systems often are accessible to anyone who dials the right telephone number, they are subject to the same kinds of manipulation.

Of course, most systems use account numbers and passwords to restrict access to authorized users. But unauthorized persons have proved to be adept at obtaining this information and using it for their own benefit. For instance, when a police computer system was demonstrated to a school class, a precocious student noted the access codes being used; later, all the student's teachers turned up on a list of wanted criminals.

Perfect Crimes. It's easy for computer crimes to go undetected if no one checks up on what the computer is doing. But even if the crime is detected, the criminal may walk away not only unpunished but with a glowing recommendation from his former employers.

Of course, we have no statistics on crimes that go undetected. But it's unsettling to note how many of the crimes we do know about were detected by accident, not by systematic audits or other security procedures. The computer criminals who have been caught may have been the victims of uncommonly bad luck.

For example, a certain keypunch operator complained of having to stay overtime to punch extra cards. Investigation revealed that the extra cards she was being asked to punch were for fraudulent transactions. In another case, disgruntled employees of the thief tipped off the company that was being robbed. An undercover narcotics agent stumbled on still another case. An employee was selling the company's merchandise on the side and using the computer to get it shipped to the buyers. While negotiating for LSD, the narcotics agent was offered a good deal on a stereo!

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3.Are these statements true or false according to the text? Correct the false statements (Intermediate).

a)Some companies are facing a security threat from their own employees under lockdown.

b)There is a growing market for cyber security groups that process data on employees’ activity.

c)Cloud security group Code 42 tracks and analyses employees’ activity on their home computers.

d)The data loss prevention market is predicted to increase its revenue from $1.2bn to $3.8bn by the end of this year.

e)People who steal data are usually doing it on behalf of foreign governments.

f)Typically, employees steal intellectual property such as reports, HR data and client lists.

g)Under lockdown, the recruitment of foreign spies takes place at events and conferences rather than online.

h)Critics of cyber security say the technology is still new and needs more investment.

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4.Replace the underlined words in the sentences using these words from the text (Intermediate).

a)Some companies believe that they face a serious __________ security threat from their own employees.

b)Some employees may leak or steal sensitive data because they are annoyed

__________ after waves of job cuts.

c)Cyber security tools alert employers to unusual __________ activity by employees online.

d)There is a rise in interest in this technology from possible __________ clients under lockdown.

e)Critics argue that staff may find the use of this technology unwelcome

__________.

f)They also say that its use might not be culturally acceptable __________.

5.Choose the best answer according to the text (Advanced)

I. Why are companies particularly worried about their employees under lockdown?

a)because they don’t know how much work their employees are doing when they are working from home

b)because employees who are not under supervision might be leaking or stealing sensitive data

c)because cyber criminals and hackers have increased their attacks on businesses during the coronavirus pandemic

II.What does the writer predict will happen to the cyber security industry?

a)It will make data loss prevention much more expensive by 2025.

b)It will see the turnover of the data loss prevention market increase by over 200% in the next five years.

c)It will see more employees sharing private data outside workplace networks.

III.How do newer data protection groups alert employers to unusual activity?

a)They inform employers when data is accessed and filtered, and stop the access automatically.

b)They inform employers and help them take appropriate action.

c)They detect when data is being accessed by analysing the behaviour they observe, such as the number of screenshots and keystrokes.

a)Financial information such as bank details.

b)Human resources data and client lists.

c)Information about new products.

V. What, in particular, has increased during the pandemic?

a)More data is being mined from internal systems to send to Saudi Arabia.

b)More adversary tactics are based on human intelligence.

c)More foreign spies are being recruited online than face-to-face.

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a)He says that the threat to companies from their own employees is a cultural human problem.

b)He says that it is not alarmist for businesses to protect against internal data breaches.

c)He says that using technology tools to monitor staff has privacy and trust implications

6.Complete the sentences using the correct form of the word in brackets at the end of each sentence (advanced).

a)Employees might ___________share private data outside of workplace networks even if they do not mean to do so. [INTENTION]

b)Some tools can detect and block the exfiltration of sensitive data ___________. [AUTOMATIC]

c)Newer groups are making use of ___________ analysis of data. [BEHAVE]

d)Demand is ___________supply in the data analysis market. [STRIP]

e)More ___________of foreign spies is taking place under lockdown. [RECRUIT]

f)Using surveillance tools on staff is ___________ and not very culturally palatable. [INTRUDE]

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