Ministry of Education and Science of the Russian Federation
Kazan State University of Architecture and Civil Engineering
Department of Industrial Safety and Law
On the topic: “Safety when working on a computer”
Completed by: st.gr.2AD-403
Zakiryanov R. F.
Received by: Associate Professor Andreeva S.A.
Kazan 2016
on the topic: “Safety when working on a computer” 1
Introduction 2
1 The impact of PCs on human health 3
2 Computer safety instructions 9
2.1 Introduction 9
2.2. General provisions 10
2.3 Types of hazardous and harmful factors 11
2.4. Electrical safety requirements 11
2.5 Fire safety requirements 14
Conclusion 14
References 15
Introduction
Among the many problems of using a computer (as the personification of new information technologies), one should be singled out in particular - the problem of the influence of a computer on human health. Its significance and relevance are determined by the speed and depth of IT penetration into all spheres of life and activity of modern society. The most significant impact from the computer is experienced by children, whose personality formation takes place in the conditions of the onset of a new information age.
Protecting the health of a PC user is a multifaceted problem that can be solved on the basis of a balanced integrated approach that takes into account a number of factors: pedagogical, medical, legal, technical, and organizational. However, despite the fact that many specialists deal with this issue, their work is still ineffective. The emphasis in covering the problem of healthy work with a computer should be transferred in pedagogical activity from the technical characteristics of computer technology (the importance of which no one questions) to the biological and social characteristics of the user. The problem of health protection is not the study of the reaction of passive organisms exposed to an electrostatic field, weak electromagnetic, X-ray and other radiation from a working active computer. These are questions of formation of adequate perception of new, special conditions of the activity.
1 The impact of personal computers on human health
Conducted medical and biological studies of the negative impact of a computer on a person note the following problems: visual impairment, cardiovascular disorders vascular system, decreased sexual activity, increased irritability, complications of pregnancy.
A classification of dangers for a person when working at a computer has been developed:
Hazardous monitor radiation;
Influence on the human psyche.
Let's take a closer look at this classification.
Hazardous radiation from a computer monitor. Until now, there is still a false opinion about the so-called computer "radiation". There is none in the traditional sense of the word. And the marking of the monitor implies that the monitor has a reduced level of electromagnetic radiation. Radiation (alpha, beta, gamma and neutron radiation) is not inherent in a computer. For any cathode-ray tube of a kinescope - both television and computer - X-ray radiation is characteristic, which occurs when electrons decelerate. In its properties, it resembles gamma radiation. However, in modern kinescopes, such effective measures are used to reduce X-ray radiation that it is practically not detected against the natural radiation background of the Earth.
In addition, monitors create an electrostatic field. During operation, the monitor screen is charged to a potential of tens of thousands of volts. A strong electrostatic field is unsafe for the human body. It is noted that ultra-low-frequency electric alternating fields increase the release of calcium ions from bone tissue. When moving away from the screen, the effect of the electrostatic field decreases significantly, and the use of special screen protective filters makes it possible to practically reduce it to zero.
During the operation of the monitor, not only its screen is electrified, but also the air in the room. He acquires positive charge. Positive air ions are dangerous to the human body. A. Chizhevsky (Russia), studying the ionization of air, came to the conclusion about the beneficial effect on the human body of negative air ions and the negative impact of positive ones. In the room where the monitor works, there are almost no negative ions, and positive ones are in abundance.
A positively charged oxygen molecule is not perceived by the human body as oxygen. There can be as much fresh air as you want in a room, but if it has a positive charge, it's the same as if it doesn't exist.
In addition, the smallest particles of dust, flying in close proximity to the display surface, are charged with static electricity and rush to the operator's face. They enter the lungs through the respiratory tract. Once on the skin, these particles clog pores, prevent the skin from “breathing”, cause an allergic reaction and contribute to the development of skin cancer. Dust is harmful to the eyes.
Electromagnetic fields pose the greatest threat to human health. Medical studies have shown that exposure to electromagnetic fields causes a change in metabolism in cells, fluctuation of ions in the human body. Electromagnetic fields affect the electrical voltage between body cells. This leads to irreversible consequences.
Specific eye strain. A person sees not so much with his eyes as with his brain. We see the world because the image that appears on the retina undergoes complex "mathematical" processing in the brain. During this processing, the image is flipped 180 ° (remember the convex lens-crystalline), all geometric distortions are eliminated in it.
The image on the display screen is also distorted, primarily by the curvature of the screen surface. However, we practically do not notice this distortion, since here the brain is also included in the work, correcting the image.
In addition, the image on the display screen will be clear only when one triad of the screen phosphor strictly corresponds to each pixel of the image, that is, when the grain size absolutely corresponds to the resolution of the video card. This condition is observed only in liquid crystal screens. For monitors on cathode ray tubes, it is practically impossible, and one pixel can capture neighboring triads. When this happens, the brain perceives the image as blurry and tries to focus it. An image on a 10-inch laptop screen with a grain size of 0.33 mm is perceived as sharper than a typical 14-inch monitor with a grain size of 0.28 mm.
An attempt to focus what is not focused and eliminate distortions, the nature of which is unpredictable, leads to a strong overload of certain parts of the brain, while others are relatively unloaded. The consequences can be serious, up to a disorder of the autonomic nervous system, cerebrovascular accident. This is especially dangerous for people suffering from vascular diseases.
There is also a lot of pressure on the eyes themselves. The muscles that change the geometry of the lens are constantly contracting in an attempt to eliminate the blur. An additional load on the eyesight gives a visually imperceptible flicker of the screen with a frame rate.
There is one more circumstance. The display screen lights up with the intensity of the lighting fixture. The range of brightness between the image on the screen and objects in the environment often exceeds the range for which the human eye is designed. This causes severe fatigue of the eye muscles and local circulatory disorders.
Incorrect lighting, an unsuccessfully chosen place for a computer and long work without interruptions also lead to eye strain. By eliminating these causes, you can minimize the harm from the technical imperfection of monitors with cathode ray tubes.
Load on the musculoskeletal system. A person working at a computer stays in a forced immobile position for a long time. And this is not about hypodynamia, although this is also relevant, it is more harmful that the muscles and bones of a person experience huge loads. The point is not in the magnitude of the loads - they are small - but in their nature. When a person sits at a computer, he stays for a long time in a position that is uncomfortable for his musculoskeletal system. In this case, the metabolism in the muscles is disturbed, the muscle tissue becomes denser, and the skeleton experiences significant static loads. Constant mechanical pressure on the nerves that are within the groups of "blocked muscles" causes shortening of the arms, the development of "neural tension".
Frequent and repetitive movements of the hands and fingers lead to microtraumas, which have come to be called repetitive stress injuries (ESIs). In the US, according to surveys of government agencies and labor unions, up to 10 million workers have experienced ESRD in their lives. The number of registered appeals for such injuries in the United States was more than 300 thousand people a year. Among the diseases of this group, the most unpleasant is chronic and very painful inflammation in the channels of the wrist, through which the vessels, nerves, and tendons pass.
Perhaps alternative keyboards have advantages for extended use. Much more than the arrangement of the keyboard, the design of the chair and the table at which one sits affects the user's health.
When working with the mouse, one brush is always involved. It is in the process of work and accounts for most of the load. In such a situation, the position of the brush on the mouse is of great importance.
When the manipulator is clamped and convulsively maintained, the hand is in an unnatural tense state for a long time, which provokes swelling of the lung tissues and overstrain of the tendons. The active work of the fingers with the button is not balanced by the work of the hand, which leads to the "effect of the first grader" - fatigue of the light muscles and the monotony of movements with great nervous tension cause fatigue of the entire hand, arm and further deterioration in the general condition and loss of attention.
The influence of the computer on the human psyche. As mentioned above, electromagnetic fields emitted by a computer have a specific effect on a living organism. In this case, computer fatigue stands out in particular. In severe cases, it outwardly resembles alcohol intoxication (staggering gait, slurred speech).
Psychologists note that the character of a person who is overly fond of communicating with a computer changes for the worse. A person becomes withdrawn, irritable, the range of his interests often narrows.
It is assumed that with the help of a computer it is possible to encode a person, change his attitudes, cause depression, fatigue, stress. All you need is the right software for this. To date, various methods and forms of influencing a person have been created. It is possible that viruses and programs have already appeared that encode or even kill users while they work or play with a computer.
Impact on the psyche and central nervous system of a person is possible through sight and hearing.
Color impact. It is proved that the red color excites, can cause an increase in blood pressure, blue, light green - soothe. Thus, using a special color scheme of the program, you can cause a certain psycho-emotional state of a person.
Forced movement of gaze direction. Neurophysiologists have found that the direction of gaze corresponds to certain sensory channels. Visual memories, internal listening to already heard sounds, memories of sensations - all this is reflected in special eye movements in strictly defined directions. Simply put, at the bottom are emotions and sensations, horizontally - sounds, above - visual images. Virtually all parts of the brain are accessible through the eyes. By organizing various stimuli or their combinations (colors, commands, rhythms, etc.) on the screen in certain places, one can make a person plunge into one state or another, significantly increasing the effect of suggestion.
Speed change. An imperceptible, but performed according to a certain program, change in the rate of change of the image can, it turns out, cause a strong physiological reaction of the user.
Sound impact. The simplest thing is to transmit at near-threshold (that is, completely invisible to consciousness) volume, controlling only frequencies and modulations sound signals, a verbal instruction for a person. A person has several levels of protection, one of which is consciousness. The more educated the individual, the more difficult it is to inspire him with something that contradicts his worldview. However, a suggestion that bypasses consciousness is usually quite effective, if it does not directly threaten the life of the recipient or is not too contrary to basic moral principles. As the possibilities of the human psyche are endless, so are the ways of influencing it - hypnosis, music therapy, etc. The computer allows all this to be combined. Therefore, both legislative and technological measures should be taken to prevent the threat of human coding. It is necessary that software products undergo special testing in the relevant laboratories.
State budget professional educational institution
“Baikonur Electro-Radio Engineering College named after M.I. Nedelina"
Lesson 24 Development
on the 2015 / 2016 academic year
by discipline "Life Safety"
specialty: 09.02.03 "Programming in computer systems";
for 3 course, groups P-34; P-35; P-37
Topic: “Safe use of a computer. Protection during PC operation.
(practical lesson)
Developed
Niyazova Alisa Vadutovna
Baikonur
Lesson (lesson) No. 24
Section 3. Ecobioprotective technique.
Practical lesson.
Lesson Objectives:
educational – to acquaint students with the purpose and classification of eco-bioprotective equipment. General concepts.
To bring to the consciousness of students the urgency of the problem of the negative impact of the computer on the performance and health of a person;
Protection during PC operation.
The use of hygienic, practical and health-improving measures for PC users from the negative impact of computers, increase their efficiency and vitality.
Educational– to instill in students an understanding of the need to minimize the harmful effects of harmful and dangerous production factors, computers on the human body;
Development of interest and ability to correctly understand the basic rules and recommendations for the safe use of a computer.
Educational- to develop a competent attitude to preserve one's health.
Lesson type- practical lesson.
educational- visual aids- posters, cards - polls.
Technical means: TV, computer.
Structural elements of the lesson:
Organizational part:
Checking the presence of students;
Familiarization with a new topic;
Ecobioprotective technology. Safe use of a computer. Protection during PC operation -
a) can be considered as a “man-machine-environment” system, because real dangers affecting the environment through technological processes through technology, really at the moment or over any period of time have a negative impact on humans;
b) connection of the topic with other topics:
"Negative factors in the system" Man - environment "";
"Dangers, consequences of exposure to dangers".
c) the connection of the topic with other disciplines - with all the disciplines of the faculty, "Physical Education", "Fundamentals of Law", "Informatics", "Labor Protection", "Psychology".
d) connection with life - everywhere, not one enterprise, educational institution and other industries can do without a computer.
Checking the quality of knowledge.
Front poll:
Practical lesson. 1. Performing a military salute without weapons on the spot and on the move. Fundamental rules.
2. Failure and commissioning, approach to the boss and departure from him Basic rules.
Practical part.
Performing a military salute without weapons on the spot and on the move. Fundamental rules. Practicing actions for evaluation.
Failure and putting into operation, approach to the chief and departure from him. Practicing actions for evaluation.
Written surveyDefine hazard.
Answer: Danger- these are processes, phenomena, objects that have a negative impact on human life and health.
Oral survey:
listening to messages, reports;
listening to the previous topic.
Ecobioprotective technology.
Safe use of a computer. Protection during PC operation.
Purpose and classification of eco-bioprotective equipment. General concepts.
Positive factors when using a computer.
1. Negative factors of computer impact on human health.
Computer radiation.
Computer vision syndrome.
Problems related to muscles and joints.
Syndrome of computer stress.
Practical part. Protection during PC operation.
Improving and preventive exercises.
A set of exercises for the eyes and muscles of the body.
Sets of exercises to relieve symptoms of computer stress syndrome.
Conclusion.
Introduction
Computer (eng. Computer - “computer”), an electronic computer (ECM) designed to transmit, store, and process information.
Computer
interactive tool
Means intellectual development
Didactic material
Universal toy
The computer has long ceased to be a luxury, it has become an integral part of life modern people like TV or watch. They have become commonplace in production, in the office, in transport, in educational institutions, in the classroom and even in kindergarten. However, we must not forget that this invention not only brings benefits, but also has an adverse effect on the human body.
Positive aspects of the computer:
Causes a positive interest in technology;
Develops creative abilities;
Eliminates fear of technology;
Forms psychological literacy to master the PC;
Develops imagination by modeling the future;
Cultivates attentiveness, concentration;
Helps to master reading, writing, etc. at a fast pace;
Trains memory, attention;
Develops speed of action and reaction;
Cultivates purposefulness.
1. Negative factors of computer impact on human health.
Many people who constantly work with a computer note that within a short time after the start of work, a headache, pain in the muscles of the face and neck, aching pain in the spine, pain in the eyes, tearing, impaired clear vision, pain when hand movement. The Russian Scientific Research Institute of Occupational Safety has conducted a biomedical study of the impact of PC on operators, which illustrates the fact that the degree of pain is proportional to the time spent on PC.
Strict norms for working with a PC should be established, especially for children and youth (20 minutes 2 times a week), and for an adult 3-4 hours a day, taking breaks every 45 minutes.
The negative impact of the computer on humans is complex. Only an integrated approach makes it possible to reliably assess the impact of a computer on a user's health.
Computer radiation.
Safe levels of radiation are regulated by the norms of the State Committee for Sanitary and Epidemiological Supervision “Hygienic requirements for video display terminals and PCs and organization of work. Sanitary norms and rules. 1996".
When all PC devices are turned on, an electromagnetic field with a complex structure is formed in the area of the operator's workplace. Electromagnetic fields pose a real threat to the computer user. Their influence on the human body has not been studied enough, but it is clear that it is not without consequences. Studies of the functional state of PC users, conducted by the Center for Electromagnetic Security, showed that in the human body under the influence of electromagnetic radiation from the monitor, significant changes in the hormonal state, specific changes in brain biocurrents, and changes in metabolism occur. Low-frequency electromagnetic fields, when interacting with other negative factors, can initiate cancer and leukemia.
It has been established that frequent exposure to electromagnetic radiation from monitors leads to abnormal outcomes (fetal fading) at all stages of pregnancy, lactating mothers lose milk.
Article 254 of the Labor Code of the Russian Federation "Pregnant and lactating women are exempt from performing work related to the use of video display terminals and PCs."
You can not put computers in the bedroom because. can cause a violation of the reproductive (childbearing) function of a person. The computer must be at least 3 meters away from the bed.
V exposure to dust and dirt.
Scientists have come to the conclusion that there are many times more harmful microbes on the keyboard than on the toilet lid, so you can’t eat or drink at the computer, microbes that enter the body cause diseases gastrointestinal tract(gastritis, ulcer, colitis, diarrhea, etc.). And a sufficient amount of dust can accumulate in the system unit. Dust attracted by the electrostatic field of the monitor sometimes causes facial dermatitis, exacerbation of asthmatic symptoms, and irritation of the mucous membranes.
What to do:
- do not sit at the computer with dirty hands;
- about once a week, wipe the keyboard with alcohol or special wipes;
- Vacuum your computer once a month. (You can do this with an ordinary vacuum cleaner only carefully), but there are also special ones.
1.2. Computer vision syndrome.
Human vision is absolutely not adapted to the computer screen, we are used to seeing colors and objects in reflected light, which has been developed in the process of evolution.
Studies show that more than 90% of computer users complain of burning or pain in the eye area, a feeling of sand under the eyelids, blurred vision, etc. The complex of these and other characteristic ailments has recently been called "Computer Visual Syndrome". The impact of working with the monitor largely depends on the age of the user, on the state of vision, as well as on the intensity of work with the display and the organization of the workplace.
As a prophylacticuse of glasses specifically designed for PC use. Computer glasses protect the eyes from the negative effects of the monitor. They increase the clarity of perception, optimize color reproduction, reduce visual fatigue, increase comfort and performance.
1.3. Problems related to muscles and joints.
In people who earn a living working on computers, the largest number of health complaints are associated with diseases of the muscles and joints, there is a change in the shape of the spine. Intensive work with the keyboard causes pain in the elbow joints, forearms, wrists, hands and fingers.
Often there are complaints of neck numbness, pain in the shoulders and lower back, or tingling in the legs. But there are, however, more serious diseases. The most common is carpal tunnel syndrome, in which the nerves of the hand are damaged due to frequent and prolonged use of the computer. In its most severe form, this syndrome manifests itself in the form of excruciating pains that deprive a person of his ability to work.
1.4. Syndrome of computer stress.
There is evidence that regular PC users are more often and to a greater extent subjected to psychological stress, functional disorders of the central nervous system, diseases of the cardiovascular system. Based on the results of the research, conclusions can be drawn about the likelihood of hormonal changes and violations of the human immune status.
The influence of a computer on the nervous system is very diverse. Remember the situation when the computer freezes or loads very slowly the desired web page. And remember how you forgot to save the right file in time and several hours of fruitful work turned out to be wasted, worried when playing computer games. The game increases the state of nervousness and fear in the desire, by all means to achieve victory. The content of the games provokes the manifestation of aggression, cruelty. But there are cases when people had heart attacks because of this!
In addition, Internet addiction and gambling are becoming common phenomena. After working at the computer, refrain from watching TV for 2-3 hours.
Against this background, medical circles have identified a new type of disease - computer stress syndrome.
The symptoms of the disease are varied and numerous. Physical ailments: drowsiness, persistent fatigue; headaches after work; pain in the lower back, in the legs; feeling of tingling, numbness, pain in the hands; tension in the muscles of the upper body.
Eye diseases: a feeling of acute pain, burning, itching.
Visual impairment: blurred vision that increases during the day; occurrence of double vision.
Deterioration of concentration and performance: concentration is achieved with difficulty; irritability during and after work; loss of operating point on the screen; typing errors.
There is an opinion that by eliminating negative factors of influence, it is possible to reduce the likelihood of the Computer Stress Syndrome to a minimum.
Practical part
Protection during PC operation.
Workplace organization.
When working on a PC, organization of work is very important. The room in which the PCs are located should be spacious and well ventilated. The minimum area for one computer is 6 m 2 , the minimum volume is 20 m 3 .
Proper organization of lighting in the room is very important. A large contrast between the brightness of the screen and the surrounding space should be avoided. It is forbidden to work on the computer in a dark and semi-dark room. Lighting should be mixed: natural and artificial. Illumination on the surface of the table in the area where the working document is placed should be at least 300-500 lux. You can get rid of the glare of sunlight with the help of window curtains, curtains, blinds. It is advisable to install the PC so that, by raising your eyes from the screen, you can see the most distant object in the room, since shifting your gaze to a far distance is one of the most effective ways to unload the visual system when working on a PC. If there are several computers, the distance between the screen of one monitor and the back wall of another must be at least 2 m, and the distance between the side walls of adjacent monitors must be 1.2 m.
3. IMPROVING AND PREVENTIVE EXERCISES
The complexes of this part have a beneficial effect and help restore the normal functioning of the eyes and muscles of the body, as well as help relieve the symptoms of computer stress syndrome.
3.1. A set of exercises for the eyes and muscles of the body
Exercise 1. Sitting at the computer, take the most comfortable position: relax, do not strain; gently, slowly, straighten your back (do not slouch); closing your eyes, gently, without squeezing, close your eyelids; with your eyes closed, look only straight ahead - without straining your eyes, defocus; hold your head easily, without straining, without effort; do not strain the body and perform slight tilts of the head: to the chest, back; in turn to the left and right shoulder.
Exercise 2. Without opening your eyes, rotate them clockwise and counterclockwise, up and down.
Exercise 3. Take a break from work at least once every two hours, lean back in your chair, put your hands on your hips, relax your facial muscles and sit like this for 10-15 seconds.
Exercise 4. Close your eyes and massage with your fingers, making light circular stroking movements from the nose outward, the brow ridges and the lower part of the eye sockets for 20-30 seconds. Then sit with your eyes closed for 10-15 seconds.
Exercise 5. Slowly tilt your head forward, resting your chin on your chest, and move your head back. Do a series of head rotations. Repeat 4-6 times.
Exercise 6. Look into the distance for 2-3 seconds, then look at the tip of the nose, freeze for 2-3 seconds. Repeat 6-8 times.
Exercise 7. If possible, raise your hands up, spread your fingers tensely, tighten all the muscles of the body, hold your breath for 7-8 seconds. With the rotation of the body, "drop" the hands and relax the whole body for 7-8 seconds. Repeat 3-5 times.
Exercise 8. Stretch and unclench your fingers so that you feel the tension. Relax, and then, slowly, squeeze your fingers.
Exercise 9. To relax your shoulders towards your upper back, interlace your fingers behind your head and move your shoulder blades until you feel tension in your upper back. Stay in this position for 5-10 seconds. Then relax. Repeat the exercise 5-10 times.
Exercise 10. Interlace your fingers behind your back with palms facing inward. Slowly try to raise and straighten your arms. Stay in this position for 5-10 seconds. Repeat 5-10 times.
Exercise 11. In a standing position, slowly raise your hands, while turning your head to the left, then to the right until you feel a slight tension.
Exercise 12. This exercise will help to neutralize the effects of a long stay in a forward-leaning position, when you look at the screen for a long time and carefully. Slowly lower your chin so that wrinkles form under it, stay in this position for 5 seconds. Repeat 5-10 times.
3.2. Sets of exercises to relieve symptoms of computer stress syndrome.
Symptom: drowsiness, fatigue.
Exercises: circular movements of the head; translation of the gaze from the near to the far distance - with one eye; translation of the gaze from the near to the far distance - with two eyes; palming.
Symptom: Headache after hard work.
Exercises: circular movements of the head; translation of the gaze from the nearest points to the far ones - with one eye; shifting gaze from corner to corner; palming; general sipping of the body; shrug (circular movements of the shoulders).
Symptom: Pain in the hips, legs, lower back.
Exercises: general sipping; sipping back muscles; tension in the lower back.
Symptom: tingling sensations and pain in the arms, wrists, palms.
Exercises: general sipping; tension of the fingers of the palm; spinal muscle tension; quick finger movements.
Symptom: Feeling of tension in the upper body.
Exercises: general sipping; spinal muscle tension; shrugging shoulders (circular movements); circular movements of the head.
Symptom: inflamed eyes.
Exercises: development of the correct blinking; fast blinking; eyelid closing exercise; circular movements of the head; shifting gaze from near to far distance with one eye; translation of sight from near to far with two eyes; focusing on the left and right corner of the room - with one eye;
Symptom: Irritability during or after work.
Exercise: eye strain; translation of the gaze from the near to the far distance - with one eye; translation of the gaze from the near to the far distance - with two eyes; alternate focusing of the gaze on the left and right corners of the room; palming.
Symptom: Typing errors.
Exercises: translation of the gaze from the near to the far distance - with two eyes; focusing on the left and right corners of the room; rotational movements with the thumbs; palming.
CONCLUSION
Recent studies by scientists have shown that not so much computer technology itself is a direct factor in the negative impact on the human body, but its incorrect location, non-compliance with elementary hygiene standards regarding work and rest.
Investigating the problem of the impact of a computer on human health, it becomes obvious that the means of modern information technology, of course, affect the user's body and "communication" with a computer requires strict regulation of working hours and the development of sanitary and hygienic measures to reduce and prevent such impacts.
Generalization and systematization.It is important whether to be able to provide first aid for heart failure, stroke, respiratory arrest and cardiac activity.
Before proceeding with the provision of first aid, what is an important point to be observed.
Homework 2 (277-283); 2 (261-262).
Lesson (lesson) No. 24
Safe use of a computer. Protection during PC operation.
Written survey1. Define the hazard.
2. List factors harmful to health.
3. List the factors dangerous to health.
Lesson (lesson) No. 24
Practical lesson. Ecobioprotective technology.
Safe use of a computer. Protection during PC operation.
Written survey2. List factors harmful to health.
3. List the factors dangerous to health.
___________________________________________________________________________________________
Lesson (lesson) No. 24
Practical lesson. Ecobioprotective technology.
Safe use of a computer. Protection during PC operation.
Written survey1. Define the hazard.
2. List factors harmful to health.
3. List the factors dangerous to health.
Computer and healthComputer. What is it: a new threat to health or a modern friend and helper? It all depends on how you approach the organization of work on the computer. With the wrong organization of the workplace and work time, all those horror stories with which he is surrounded can become a reality. Should you give up your computer? Should he be afraid? Isn't it better to follow simple rules all the time? With good workplace equipment and the right choice of occupation, the computer turns from a monster of horror stories into a very useful tool that makes our lives very easy. The coming century is the era of information technology. It will still not be possible to separate children from the computer, and it is not necessary. The ability to make quick decisions and not get lost when a failure occurs and what the child does not expect on the screen will help in solving more complex problems. And you can protect children's health from computer hazards - just make sure that the child follows the rules that you yourself adhere to when sitting at the computer. |
The main harmful factors when working at a computer:
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You should sit up straight (not slouched) and lean your back against the back of the chair. You need to bend your back in the lumbar region not back, but, on the contrary, a little in front. The design of the working chair (chair) should ensure the maintenance of a rational working posture when working with a computer, allow changing the posture in order to reduce the static tension of the muscles of the neck-shoulder region and the back to prevent the development of fatigue. It is unacceptable to work lounging in a chair. This posture causes rapid fatigue, decreased performance. The type of work chair (chair) should be selected depending on the nature and duration of work, taking into account the height of the user. Get a comfortable work chair that will allow you to effortlessly maintain the correct posture at the computer. It is desirable that you can adjust the height of the seat and tilt the back, move on rollers. The width and depth of the seat must be at least 40 cm, the height of the back support surface is 30 ± 2 cm, the width is not less than 38 cm, the length of the armrests is not less than 25 cm, the width is 5-7 cm, the height above the seat is 23 ± 3 cm. Ideal the back of the chair repeats the curves of the spine and serves as a support for the lower back. The seat is slightly tilted forward, which somewhat transfers pressure from the spine to the hips and legs. The edge of the seat is slightly curved - this reduces pressure on the hips. The chair (chair) should be hard or semi-rigid, this will improve blood circulation in the pelvis, with a non-slip, non-electrifying and breathable coating that provides easy cleaning from dirt. The location of frequently used things should not force you to stay in a crooked position for a long time, lean to the side, especially to lift heavy objects (with such a tilt, there is a high probability of damaging the intervertebral disc). Arrange items on the table so that they can be easily reached. Those that you use often, place closer (in the area of \u200b\u200boutstretched arm), and the rest further. For papers, books and printouts, it is advisable to use a special stand. |
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If the chair and the table are uncomfortable, if there are no stands for text (music stand), for hands and feet, then muscle tension increases, which leads to physical overstrain, weakening of attention, and decreased efficiency. The monitor must be installed at such a height that the center of the screen is 15-20 cm below eye level, the angle of inclination is up to 15 0 (i.e., approximately, the upper part of the screen should be at eye level (when using glasses with bifocal lenses - below eye level). posters, picture frames) The screen surface must be clean and free of glare. |
It is necessary to find a head position in which the muscles of the neck are less tense. The recommended tilt angle of the head is up to 20 0 . In this case, the load on the cervical vertebrae and on the eyes is significantly reduced. During work, it is necessary to relax your hands, keep your forearms parallel to the floor, on the armrests of the chair. The hands are at the level of the elbows or slightly lower, the wrists are on the support bar. Then the fingers get the greatest freedom of movement. You should not raise your wrists high and arch your hands - this can cause pain in the hands and numbness of the fingers. you can wear light gloves without fingers if your hands get cold. Knees - at the level of the hips or slightly lower. With this position of the legs, muscle tension does not occur. You can not cross your legs, put your foot on your foot - this disrupts blood circulation due to squeezing of blood vessels. It is better to keep both feet on a stand or the floor. It is necessary to maintain a right angle (90 0) in the area of the elbow, hip and ankle joints. In order not to injure the spine, it is important: avoid sudden movements; rising / sitting down, keep your head and torso straight. It is also necessary at work. breathe rhythmically, freely, deeply to provide oxygen to all parts of the body; keep your shoulders and arms relaxed - there will be no tension in your arms if your shoulders are lowered; blink more often and look into the distance. Blinking contributes not only to moisturizing and cleansing the surface of the eyes, but also to relaxation of the facial, frontal muscles (without moving the eyebrows). Low mobility and prolonged tension of the eye muscles can cause disturbances in accommodation. If you feel tired in some part of the body, take a deep breath and strongly strain the tired part of the body, then hold your breath for 3-5 seconds and relax as you exhale, then you can repeat. If you feel tired eyes, you should look around the room for 2-3 minutes, look at different objects, look into the distance (out the window). If there is a sudden general fatigue, a trembling image appears on the screen (swaying, twitching, ripples), you should immediately inform the teacher (teacher) or supervisor. |
Rest break...
1. Sit comfortably, leaning back freely in your chair. For one or two minutes, just breathe slowly and deeply. You can even close your eyes if you like. Count to three (five) as you inhale and count to five (seven) as you exhale. Taking more time to exhale creates a mild calming effect. Imagine that when you enjoy this deep, leisurely breathing, all the troubles, irritation, anxiety gradually disappear.
Do you feel like stretching? Don't hold back this natural desire. Stretch with pleasure, moving your bent arms to the sides, trying to connect the shoulder blades.
Putting your hands on the back of your head, first tilt your head forward, helping this movement, then back, resisting with your palms. Interlace your fingers in a lock and stretch your arms as far forward as possible, twisting your hands.
2. Try shiatsu - a method that allows you to use the reserve forces of the body and can be recommended to everyone, regardless of age and blood pressure level. Place your hands on the back of your neck, press the pads of your middle fingers in the suboccipital fossa. Count to five and release.
Then, using three fingers of both hands, press on the points located on the neck along the spine and on the temples. These simple techniques, repeated two or three times each, will help you regain your attention and ability to work in a matter of minutes.
3. Now let's take care of the eyes, especially if you spend most of your working time at the computer, reading or writing. First, remember to give your eyes a chance to rest often. Shift your gaze into the distance, look out the window, at the greenery of the trees, at the sky, “go out” for a moment under the cold rain or into the snow blizzard.
Is there no such possibility? It's a pity. There is a white wall and a monitor screen in front of you all day long, there is nothing to distract and please the eye. Take the liberty to break the dreary monotony of black and white graphics. Decorate your workspace with a houseplant. Floral arrangements or miniature Japanese bonsai trees look very impressive. Hang a colorful calendar, landscape, etc. in front of you, modern printing allows you to achieve depth and naturalness of the image.
Blink your eyes more often, as often as possible, this elementary measure will allow your eyes to rest without interruption. Close your eyes tightly for 3-5 seconds. Open. Repeat several times.
Then close your eyes again and make circular movements with your eyeballs to the right and left.
The following exercise will improve blood circulation in the eyes and relax tired eye muscles. Sit quietly, leaning back in your chair (it is desirable that there are no bright light sources in the field of view). Close your eyes and relax your eyelids. You can mentally stroke your eyes with warm fingers. Feel how the eyeballs lie completely passive in the sockets. The face and body are also relaxed, this will give additional rest. Sit like this for one or two minutes, then gently press on the closed eyes with the pads of your fingers for ten seconds two or three times.
4. What to do if your hands get tired? Gymnastics for the hands is vital for everyone who writes a lot, prints, etc., whose hands and fingers are in constant tension. It is necessary at the first signs of fatigue of the hands to give them rest, to regularly carry out special exercises and massage. It is known that the fingers of the hands are closely connected with the brain. Spending a few minutes a day on special exercises for the fingers, you can significantly increase your performance. Start with a relaxation exercise. Lower your hands down and shake your brushes several times as if you are trying to throw drops of water from your fingertips. Then rub each finger well, paying special attention to the joints. If you have very little time, you can limit yourself to general rubbing of the brushes.
Grab the finger of the left hand in the nail area from the sides, pull it slightly, and then rotate the straightened finger in one direction and the other. Try to rotate your finger, not your hand. From little finger to thumb.
Another exercise for training the mobility and dexterity of the hand: bending each finger back to the limit with the help of a “fork” from the index and middle fingers of the other hand. Now try, putting your palms together, bend your fingers back as much as possible.
And most importantly, do not forget that you are resting. Drop all worries and problems. Your rest is the most important thing in the world right now. Enjoy your vacation! Rejoice!
Fatigue exercises.
Effect: relaxation of the body, relieving nervous tension, restoring the normal rhythm of breathing.
- Slowly lower your chin to your chest and stay in this position for 5 seconds. Do 5-10 times.
- Lean back in your chair, put your hands on your hips, close your eyes, relax and sit like this for 10-15 seconds.
- Straighten your back, relax your body, gently close your eyes. Slowly tilt your head forward, backward, right, left.
- Sitting straight with your hands down, sharply tighten the muscles of the whole body. Then quickly completely relax, lower your head, close your eyes. Sit like this for 10-15 seconds. Do the exercise 2-4 times.
- Sit comfortably with your legs slightly apart. Put your hands on the middle of your stomach. Close your eyes and take a deep breath through your nose. Hold your breath (as far as possible). Exhale slowly through your mouth (completely). Do the exercise 4 times (if dizziness does not occur).
Eye exercises.
- Close your eyes, relax your forehead muscles. slowly shift the eyeballs to the extreme left position with tension, after 1-2 seconds, also look to the right. Do 10 times. Make sure that the eyelids do not tremble. Don't squint.
Effect: relaxation and strengthening of the eye muscles, getting rid of pain in the eyes.
- Blink for 1-2 minutes.
- with tension, close one and the other eye alternately for 3-5 s.
- Within 10 seconds, close your eyes tightly several times.
- Within 10 seconds, change the direction of gaze: straight, right, left, up, down.
- Rub your palms together to create a feeling of warmth. Cover your eyes with your palms, crossing your fingers in the center of your forehead. Completely exclude access to light. Do not press on the eyes and eyelids. Relax, breathe freely. Stay in this position for 2 minutes.
Effect: chemical restoration of eye receptors, relaxation of the eye muscles, improvement of blood circulation in the visual apparatus, getting rid of the feeling of eye fatigue.
Exercises for the head and neck.
- Massage your face to relieve facial muscle tension.
- Pressing your fingers on the back of the head for 10 s, make rotational movements to the right, then to the left.
Effect: relaxation of the muscles of the neck and face.
- Close your eyes and take a deep breath. As you exhale, slowly lower your chin, relax your neck and shoulders. Again a deep breath, a slow circular movement of the head to the left and exhale. Do 3 times to the left, then 3 times to the right.
Effect: relaxation of the muscles of the head, neck and shoulder girdle.
Hand exercises.
- In a sitting or standing position, place your hands in front of your face. Palms out, fingers extended. Tighten your palms and wrists. Gather your fingers into fists, quickly bending them one by one (starting with the little fingers). The thumbs will be on top. Turn strongly clenched fists so that they "look" at each other. Movement - only in the wrists, the elbows are not mobile. Unclench your fists, relax your hands. Do the exercise a few more times.
Effect: relieving tension in the hands and wrists.
- In a sitting or standing position, lower your arms along the body. Relax them. Take a deep breath and slowly exhale for 10-15 seconds, shake your hands slightly. Do this several times.
Effect: getting rid of hand fatigue.
- Interlock your fingers, join your palms and raise your elbows. Turn the brushes with your fingers inward (toward the chest), then outward. Do it several times, then lower your arms and shake your relaxed hands.
- Snap the fingers of both hands, moving the thumb in turn to all other fingers.
- Spread your fingers wide and strain your hands for 5-7 s, then strongly clench your fingers into fists for 5-7 s, then open your fists and shake your relaxed hands. Do the exercise several times.
Body exercises.
Effect: muscle relaxation, straightening of the spine, improved blood circulation.
- Stand up straight, legs slightly apart. Raise your hands up, rise on your toes and stretch. Get down, arms along the body, relax. Do 3-5 times.
- Raise your shoulders as high as possible and gently move them back, then slowly push them forward. Do 15 times.
- Standing bend over, put your palms on your legs behind your knees. Pull in the stomach and tighten your back for 5-6 s. Straighten up and relax. Do the exercise 3-5 times.
- Stand straight, feet shoulder-width apart. Spread your arms out to the sides at shoulder level. Turn your torso to the right as much as possible, then to the left. Do this 10-20 times.
- Feet shoulder-width apart, slightly relaxed and bent at the knees. Taking a deep breath, relax. As you exhale, raise your hands up, pull them to the ceiling. Feel the tension in the muscles of the fingers, shoulders, back and again - a deep breath.
As you exhale, lean forward and touch the floor in front of your toes with your hands. Lower your head, relax. Inhale - and on the exhale straighten up. Do the exercise 3 times.
It's no secret that computerization today is considered to be a panacea - only a computer can increase the efficiency of education and industry, banking and trade, unite the whole world through the Internet! And, obviously, this "pandemic" is unstoppable... Like any new stage in the development of society, computerization brings with it new problems. And one of the most important is ecological. A lot of words in the press and in other media have been said about the harmful effects of the computer on the health of users. Some brisk authors even threaten extinction to humanity sitting behind the displays. But computers today are used not only by professionals, but also by ordinary users. The main thing is children! Pupils, teenagers, students study in display classes available in almost all educational institutions. PC displays (or, if you prefer, PCs) glow at home, slot machine screens sparkle in basements and in cinema foyers!
Is it scary or not? If scary, then why, and how to combine this given with the safety of users? It is necessary to objectively evaluate these problems, because in order to combat any danger, first of all, you need to know what it is! At environmental problem computerization has two components.
The first is determined by the peculiarities of human visual work at the computer and the properties of vision.
· The second - the technical parameters of computerization tools.
These components - "human" and "technical" - are closely intertwined and interdependent. The study of such problems is the subject of ergonomics, a science whose main goal is the creation of perfect and safe equipment that is maximally human-oriented. Ergonomics studies labor activity in a complex, it combines scientific disciplines that previously developed independently of each other.
Already in the early years of computerization, a specific visual fatigue among display users was noted, which received the general name "computer visual syndrome" ( CVS-Computer Vision Syndrome). There are several reasons for its occurrence. And, above all, the human visual system, formed over millions of years of evolution, which is adapted to perceive objects in reflected light (pictures of nature, drawings, printed texts, etc.), and not to work with a display. The image on the display is fundamentally different from the objects of observation familiar to the eye - it glows; consists of discrete points; it flickers, i.e. these points light up and go out with a certain frequency; the color computer image does not correspond to natural colors, (the emission spectra of phosphors differ from the absorption spectra of visual pigments in the cones of the retina, which are responsible for our color vision). On fig. 1 shows the appearance of the characters reproduced on the display screen, with a different number of lines and elements per character.
Principles for the formation of symbols on the display:
A - with a different number of lines per character;
B - with a different number of elements of the sign matrix
But not only the features of the image on the screen cause visual fatigue. When working on a computer for hours, the eyes do not have the necessary phases of relaxation, the eyes strain, their performance decreases. The organ of vision experiences a great load when entering information, since the user is often forced to look from the screen to the text and keyboard, which are at different distances and differently illuminated.
What is visual fatigue? Today, millions of users complain about blurred vision, difficulty shifting their gaze from near to far and from far to near objects, an apparent change in the color of objects, their double vision, discomfort in the eye area - a burning sensation, "sand", redness of the eyelids. However, in adults, after the cessation of work and a period of rest, these subjective phenomena sooner or later, as a rule, disappear. According to ophthalmologists, working on a computer for adults while observing "computer hygiene" does not inevitably lead to serious eye diseases.
Unfortunately, this is not the case for children. Working with a child's display can cause permanent damage to the eyes. The optical apparatus in adolescence and young age is still being formed. And with prolonged work with displays, acquired myopia often occurs and rapidly progresses (according to WHO experts, at a rate of up to 1.0 diopters per year). An unfavorable effect of computer work on the state of the visual analyzer in schoolchildren of grades 1-3 was noted in 45.4 ± 3.0% of studies, expert surveys suggest that 55-85% of older students complain of eye fatigue on the days of working on a PC. The visual and neuropsychic stress from the work of children at the computer, in addition to visual impairment, can lead to spasms of the muscles of the face, headaches, called "video game epilepsy syndrome."
Important note: the modern TV screen is also not natural for the human visual system! But on TV, we view the image as a whole and from afar - the plot, the general plan, the dynamics of events are important to us, and there is no need to strain the visual system to see the earrings of the singer or the drawing of the tie of the TV news anchor. Another thing is the image on the display with which we work, enter or read text, tables, draw graphs or study the details of the drawing. In this sense, gaming on a computer is closer to working on a display than watching TV: both the viewing distance is shorter and the details of the image in a computer game are important, so you should remember the need for ergonomic safety for both gaming machines and game consoles for TVs.
All these visual aspects of the ecological problem of computerization are being studied today within the framework of a new direction of science - ophthalmoergonomics, since visual discomfort to one degree or another can manifest itself when using not only CRTs, but also advanced liquid crystal, gas discharge and electroluminescent screens.
The ergonomic safety of a computer is evaluated according to two lists of requirements: to the visual parameters of displays (taking into account the light climate of the workplace) and to emission parameters - radiation from displays and PCs.
visual requirements must guarantee the comfort of the user, i.e., minimal visual fatigue with a given accuracy, speed and reliability of information perception. It is because of the peculiarities of visual perception that visual requirements are divided into two groups.
The first one has four options:
Brightness,
illumination,
Angular sign size
Observation angle
rationing, which in order to ensure the ergonomic safety of the computer is interdependent.
The parameters of the second group
Brightness unevenness
flickering
jitter
Geometric and non-linear distortions, etc.
(there are more than 20 parameters in total) are independent, and each of them can be measured separately.
For a person in the overall assessment of the image, all four main visual parameters of the first group are important at the same time. Therefore, the ergonomic safety of displays can only be ensured when their values are combined in certain ranges - optimal (maximum visual comfort) and acceptable (comfort not lower than normal). Only in this way can the visual load be minimized.
In real conditions, the range boundaries will have to be adjusted depending on the ratio of the screen glow spectra and ambient light, on the colors of the sign and background reproduced by the display (some pairs of colors not only tire the eyesight, but can also lead to stress). There is a difference in the quality of perception of information, and, consequently, in the values of the boundaries of the ranges, when working with dark signs on a light background (direct contrast) and with light signs on a dark background (reverse contrast), which require different lighting conditions at the workplace.
The comfort and safety of visual work with the display largely depends on the contrast of the image, i.e. the ratio of its brightness to the brightness of the background. Background brightness is formed due to diffuse reflection of the external light flux from the tube phosphor and due to specular reflection from the screen glass. In some new CRTs, to reduce the reflected diffuse light flux, a black coating is applied between the grains of colored phosphors, and dark glass with a transmittance significantly less than 100% is also used. In this case, the external luminous flux, as shown in Fig. 2, passing through glass with a transmittance, for example, 0.5, will be absorbed twice, and attenuated by 4 times, and the CRT's own radiation will only be 2 times, and the image contrast will increase.
Specular reflections of the CRT screen surface of light sources, windows, shiny cases and parts of equipment form glare, creating additional strain on vision. Sometimes bright reflections can completely mask parts of the image on the display. They interfere with work, distract and irritate the reflections in the screen of light walls, clothes, and even your own face.
Decreasing the mirroring amount of the display screen- one of the important requirements of ergonomic safety, so some new CRTs have special anti-reflective coatings.
A property that is very harmful to vision, characteristic of most displays used today in Russia, is image flicker due to the low refresh rate of information on the screen (frame scan). To reduce the visibility of flickering, simultaneously with an increase in contrast, allow CRTs with light-absorbing glasses used in new generations of displays, which, in addition, provide a fairly high frame rate.
Naturally, in order for the display not to be a source of danger, all other visual parameters must comply with modern requirements. But the main thing is that an integrated approach to ergonomic safety in terms of visual parameters is needed, taking into account both the peculiarities of vision and the technical parameters of the equipment.
Rice. 4. Recommended location of workplaces in the display class
Emission Requirements displays and PCs are undoubtedly important, since, according to Russian and foreign experts, fields and radiation from computers, primarily electrostatic and alternating electromagnetic fields, can be dangerous for human health.
The electrostatic potential is formed due to the high accelerating voltage of the CRT. Negative ions flow from the space between the user and the display onto the positively charged surface of the tube screen. As a result, the concentration of positive ions and positively charged particles of dust and smoke increases in this zone. It can be unequivocally stated that with prolonged work this causes diseases of the respiratory tract and skin of the face and hands (dermatitis).
The sources of alternating electric and magnetic fields in a PC are both the display itself and other blocks and circuit elements (Fig. 3).
Rice. 3. Sources of personal computer fields
Variable fields occur not only in computers with CRT displays, but also in portable computers with liquid crystal screens. unevenness and complex shape distribution of alternating electromagnetic fields in some cases can pose a greater danger of exposure to neighbors in the working room than to the user of this PC. This circumstance must be taken into account when choosing the location of computers in the workplace.
Rice. 5. Distribution of electric variable and electrostatic fields of a personal computer:
A - in the frequency range 5 Hz - 2 kHz;
B - in the frequency range 2 - 400 kHz;
B - electrostatic field.
According to many experts, low-frequency alternating electromagnetic fields during prolonged exposure to people sitting at the PC can also cause or intensify disturbances in various physiological processes in them. Today, specific quantitative relationships have not been established between the levels, frequency ranges of variable PC fields and certain diseases, but the fears of hygienists seem quite convincing.
According to domestic and foreign data, in modern displays, X-ray and ultraviolet radiation are at the level of the natural background. But, keeping in mind the tendency to increase the size of CRT screens and, consequently, to increase the anode voltage, it is necessary to mention these radiations.
microtrauma- This is the gradual wear and tear of the body as a result of daily stress. Most disorders in the body occur due to accumulating microtraumas. This type of injury does not occur suddenly, like a broken arm or leg ( macrotrauma). It may take several months of sitting in the wrong position or repetitive movements before you feel pain. Pain can be felt in different ways: in the form of burning, stabbing or shooting pain, tingling.
Posture is the position your body assumes when you are sitting at a computer. Correct posture is essential for the prevention of diseases of the neck, arms, legs and back. It is necessary to organize the workplace in such a way that the posture is optimal.
Correct posture
When working at a computer, it is best to sit 2.5 cm higher than usual. The ears should be placed exactly in the plane of the shoulders. The shoulders should be positioned directly over the hips. The head should be kept level with respect to both shoulders, the head should not lean towards one shoulder. When looking down, the head should be exactly above the neck, and not lean forward.
Wrong posture.
Hunched position:
Increases the already large load on the spine.
Causes the fluid contents of the intervertebral discs of the lumbar spine to flow back
Leads to excessive stretching of the muscles that support posture.
A hunched position can lead to various diseases.
Head pushed forward:
This posture often occurs for the following reasons:
· looking at the monitor screen, the user tenses up, which makes him stretch his neck forward;
Sitting in this position, you have to tilt your head back to see an object located directly in front of you. This increases the deflection of the cervical spine;
pulling the head forward causes tension in the muscles of the base of the head and neck, which limits the blood flow in the vessels of the neck, i.e. blood supply to the head and outflow of blood from it. Tight muscles at the base of the head and neck when the head is pulled forward can lead to disorders (headaches, neck pain, pain in the arms and hands).
Slouch
The line of the shoulders is not located exactly above the line of the hips and under the line of the ears. Stooping causes excessive stress on the shoulder tendons, which leads to tension in the muscles of the shoulder. Slouching can lead to the development of:
carpal tunnel syndrome
Shoulder impingement syndrome.
carpal tunnel syndrome (SZK) is essentially a wrist injury. To understand its essence, it is necessary to understand physiology. The wrist is the junction of the radius and ulna (forearm bones) and the eight bones of the hand (small bones of the palm). The median nerve and 9 tendons of the muscles of the hand pass through the carpal tunnel. The median nerve provides sensation to the surface of the thumb, index and middle fingers on the palm side, the surface of the ring finger facing the thumb, and the back of the tips of the same fingers. The median nerve innervates the muscles that provide movement of the thumb, index and middle fingers.
A condition called carpal tunnel syndrome (CTS) is caused by entrapment of the median nerve in the carpal tunnel. It occurs when the median nerve and/or tendons of the hand are swollen. Most often, SZK is the result of many hours of sitting at a computer with an incorrect posture.
Accumulating trauma causes accumulation of decay products in the carpal tunnel. If the user does not take regular breaks and do simple hand exercises, the breakdown products cause swelling and then CTS.
Symptoms of SZK:
Burning pain and tingling in the area of divergence of the branches of the median nerve (wrist, palm, and fingers, except the little finger).
Weakening of the muscles that move the thumb.
· Soreness and numbness, forcing to wake up.
Clumsiness and weakness of the affected hand.
Staying in the same position for a long time causes the muscles to work continuously without rest. Adequate blood supply is necessary to remove decay products and nourish the muscles. Even a slight change in body position every half hour shifts the load on other muscles, which allows the muscles to rest and store fuel (nutrients).
Muscles that support body position (posture)
The muscles of the back, neck and abdomen support the vertical position of the body. They must receive sufficient blood supply to keep their heads upright and back straight throughout the day. Strong muscles help maintain proper posture for longer periods of time and increase productivity.
1.Ergonomic hardware
To work comfortably and safely, you need to take care of your computer hardware. As a rule, I / O devices cause the greatest harm to the health of a computer user: monitor, keyboard, mouse.
In our time, when the safety problems of working at a computer are as acute as possible, there are many different standards for the environmental safety of personal computer equipment. A modern monitor must meet at least three generally accepted standards for safety and ergonomics:
1. FCC class B - this standard was developed by the Canadian Federal Communications Commission to provide acceptable environmental protection from the influence of radio interference in a confined space. Compliant equipment FCC class B, should not interfere with the operation of television and radio equipment.
2. M PR - II - this standard has been issued by the Swedish National Department. M PR - II imposes limits on emissions from computer monitors and industrial equipment used in the office .
3. TCO ’95 (as well as modern TCO ’99 ) - recommendation developed by the Swedish Trade Union Conference and the National Board of Industrial and Technical Development of Sweden ( NUTEK ) , governs interaction with environment . It requires the reduction of electric and magnetic fields to a technically feasible level in order to protect the user. In order to get a certificate TCO ’95 ( TCO ’99 ) , the monitor must meet low emission standards ( L ow Radiation ), i.e. have a low level of electromagnetic field, provide automatic reduction of energy consumption when not used for a long time, meet European fire and electrical safety standards
4. EPA Energy star VESA DPMS - according to this standard The monitor must support three power-saving modes - expectation(s tand - by ), suspension ( suspend ) and “dream ”(o ff ) . Such a monitor, when the computer is idle for a long time, is transferred to the appropriate mode, with low power consumption.
It is also necessary that the monitor has the ability to adjust image parameters (brightness, contrast, etc.). It is recommended that when working with a computer, the vertical refresh rate of the monitor be at least 75 Hz (in this case, the user stops noticing the flickering of the image, which leads to rapid eye fatigue).
Currently, many monitor manufacturers have begun mass production of the so-called flat panel monitors ( LCD ) , which are devoid of many environmental disadvantages inherent in cathode ray tube monitors: electromagnetic radiation, magnetic field, flicker, etc.
2. Information input devices
Unlike monitors for computer input devices (keyboard and mouse), there are currently no generally accepted and widely accepted standards. At the same time, many manufacturers of this equipment, advertising their products, describe various design solutions that increase the ergonomics of its use: a keyboard with the ability to adjust the location of the keys, a mouse with a shape that reduces hand fatigue during prolonged use. Although some of them should be considered only as catchy advertisements, many models really are a kind of technological leap forward in terms of the safety of working at a computer.
Even the most ergonomic equipment in the world will not help you avoid illness if used incorrectly. By following simple tips for an ergonomic workplace, you can prevent the further development of diseases.
Working space.
The scientific organization of the working space is based on data on the average coverage area of human hands - 35-40 cm. The near zone corresponds to the area covered by the arm with the elbow pressed to the body, the far zone corresponds to the area of the outstretched arm.
- Work with the keyboard.
Incorrect hand position when typing on the keyboard leads to chronic wrist sprains. It is important not so much to move the keyboard away from the edge of the table and rest the hands on a special platform, but to keep the elbows parallel to the surface of the table and at right angles to the shoulder. Therefore, the keyboard should be located 10-15 cm (depending on the length of the elbow) from the edge of the table. In this case, the load falls not on the hand, in which the veins and tendons are close to the surface of the skin, but on the more "fleshy" part of the elbow. Modern, ergonomic models have an optimal area for the keyboard due to the location of the monitor in the widest part of the table. The depth of the table should allow you to fully put your elbows on the table, pushing the keyboard to the monitor.
- Monitor location.
The monitor is usually too close. There are several scientific theories that define significant factors and optimal distances from the eye to the monitor in different ways. For example, it is recommended to hold the monitor at arm's length. But at the same time, that a person should be able to decide for himself how far the monitor will stand.
That is why the design of modern tables allows you to change the depth of the monitor in a wide range. The upper limit is at eye level or not less than 15 cm below eye level.
Internal volume.
A significant factor is under countertop space. The height of our tables complies with generally accepted standards, and is 74 cm. It should also be taken into account that the space under the chair and table should be enough to comfortably bend and unbend your knees.
- Armchair
It would seem that the requirements for it are extremely simple to formulate - it should be convenient. But that's not all. The chair should provide a physiologically rational working posture, in which blood circulation is not disturbed and other harmful effects do not occur. Armchair necessarily should be with armrests and be able to rotate, change the height and angle of the seat and backrest. It is desirable to be able to adjust the height and distance between the armrests, the distance from the back to the front edge of the seat. It is important that all adjustments are independent, easy to implement and have a secure fit. The chair should be adjustable, with the ability to rotate in order to reach far-off objects.
- Position at the computer
The regulated equipment must be such that the following provision can be adopted:
· Place your feet flat on the floor or on a footrest.
The loin is slightly arched, resting on the back of the chair.
Hands should be comfortably placed at the sides.
Shoulder line should be directly above the hip line.
· The forearms can be placed on the padded armrests at such a height that the wrists are slightly lower than the elbows.
Elbows are bent and about 3 cm from the body.
Wrists should be in a neutral position (neither up nor down).
Electric current is a hidden type of danger, because. it is difficult to determine it in current - and non-current-carrying parts of the equipment, which are good conductors of electricity. A current whose value exceeds 0.05A is considered deadly to human life, a current less than 0.05A is safe (up to 1000 V). In order to prevent electric shock, only persons who have thoroughly studied the basic safety rules should be allowed to work.
In accordance with the rules of electrical safety in the office, constant monitoring of the condition of electrical wiring, safety shields, cords, with which computers, lighting devices, and other electrical appliances are connected to the electrical network, should be carried out.
Electrical installations, which include almost all computer equipment, pose a great potential danger to humans, since during operation or maintenance work, a person can touch live parts. The specific danger of electrical installations - current-carrying conductors, cases of computer racks and other equipment that is energized as a result of damage (breakdown) of insulation, do not give any signals that warn a person about the danger. A person's reaction to an electric current occurs only when the latter flows through the human body. Of exceptional importance for the prevention of electrical injuries is the proper organization of maintenance of existing electrical installations of the CC, repair, installation and maintenance work.
In computer centers, discharge currents of static electricity most often occur when you touch any of the computer elements. Such discharges do not pose a danger to humans, but in addition to unpleasant sensations, they can lead to failure of the computer. To reduce the magnitude of the emerging charges of static electricity in the CC, the coating of technological floors should be made of a single-layer polyvinyl chloride antistatic linoleum. Another method of protection is to neutralize the charge of static electricity with ionized gas. In industry, radioactive neutralizers are widely used. The general measures of protection against static electricity in the CC include general and local air humidification.
These requirements are described in sanitary norms and rules (SanPiN). Artificial lighting in the PC operating rooms is carried out by a system of general uniform lighting.
In production and administrative and public premises, in cases of predominant work with documents, the use of a combined lighting system is allowed (in addition to general lighting, local lighting fixtures are additionally installed to illuminate the area where documents are located).
Illumination on the table surface in the area where the working document is placed should be 300-500 lux, it is also allowed to install local lighting fixtures to illuminate documents, but on such a condition that it does not create glare on the screen surface and does not increase the screen illumination by more than 300 lux.
As light sources in artificial lighting, fluorescent lamps of the LB type should be used predominantly. When arranging reflected lighting in administrative and public premises, the use of metal halide lamps with a power of up to 250 W is allowed. It is allowed to use incandescent lamps in local lighting fixtures.
General lighting should be performed in the form of solid or intermittent lines of lamps located on the side of the workplaces, parallel to the user's line of sight with a row arrangement of the PC. With a perimeter arrangement of computers, the lines of lamps should be located localized above the desktop, closer to its front edge facing the operator.
To ensure the normalized values of illumination in the premises where the PC is used, it is necessary to clean the glass of window frames and lamps at least twice a year and to carry out timely replacement of burned-out lamps.
Fire safety is the state of an object in which the possibility of a fire is excluded, and in the event of a fire, the impact on people of fire hazards is prevented and material assets are protected.
Fire safety is ensured by a fire prevention system and a fire protection system. All office premises must have a "Plan for the evacuation of people in case of fire", which regulates the actions of personnel in the event of a fire and indicates the location of fire equipment.
Fire protection is a set of organizational and technical measures aimed at ensuring the safety of people, preventing fire, limiting its spread, and creating conditions for successful fire extinguishing.
In modern computers, there is a very high density of electronic circuit elements. Connecting wires and cables are located in close proximity to each other. When an electric current flows through them, a significant amount of heat is released. In this case, the insulation may melt. To remove excess heat from the computer, ventilation and air conditioning systems are used. In continuous operation, these systems represent an additional fire hazard.
Computer technology is developing especially rapidly today, various technical solutions and standards appear with extraordinary speed, and also quickly become obsolete and die off. According to the forecasts of various economic and sociological organizations, computer technology and telecommunications will remain one of the most developing branches of the world industry for at least another 10-15 years. So there is no need to wait for a decrease in the number of people working at computers. On the contrary, endemic computerization, which has long engulfed the business sector, is now increasingly capturing the mass consumer. In a race like this, where nothing is permanent, it's hard to make recommendations, make any lasting decisions, much less set standards. And therefore, until the computer boom subsides, more and more new tasks will arise regarding the organization of safe and comfortable conditions for people working with computers.
1. Ergonomic Design™ materials,
http://www.ergonomic.ru
2. Litvak, I., "Ergonomics is a caring science" http://www.osp.ru/school/1999/5/13.htm
http://www.osp.ru/school/1999/5/16.htm
3. Wilson R. Man at the computer. PC World, No. 1-1991.
4. SanPiN 2.2.2.542-96. Hygienic requirements for video display terminals (VDTs). Personal electronic computers (PC) and organization of work. M.: Information and publishing center of the State Committee for Epidemiological Surveillance of Russia, 1996.
5. Seidler, D. (Seidler, D.), Bonomo P., (Bonomo P.), "Guide to Ergonomics",
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Federal State Autonomous Educational Institution
higher professional education
Belgorod State National Research University (NRU "BelSU")
Faculty of Computer Science and Telecommunications
Department of Applied Informatics
Computer security
11th grade student
MBOU secondary school №16
Panova Dmitry
Belgorod 2012
- Introduction
- 1. Computer crimes
- 2. Viruses and the fight against them
- 2.1 Choosing a protection system
- 2.2 Use of passwords
- 2.3 Email Security
- 2.5 Antivirus programs
- List of used literature
Introduction
Since the late 80s and early 90s, problems related to information security have been a concern for both computer security specialists and numerous ordinary users of personal computers. This is due to the profound changes that computer technology brings to our lives. The very approach to the concept of "information" has changed.
This term is now more used to refer to a special commodity that can be bought, sold, exchanged for something else, etc. At the same time, the cost of such a product often exceeds the cost of the computer technology itself, within which it functions, by tens or even hundreds of times. Naturally, there is a need to protect information from unauthorized access, theft, destruction and other criminal acts. However, most of the users do not realize that they constantly risk their security and personal secrets. And only a few protect their data in any way. Computer users regularly leave even data such as tax and banking information, business correspondence and spreadsheets completely unprotected.
System administrators can increase security indefinitely, but there is always a way around it. Most people think and act in the same way. What one person thought of, another will think of, what one hid - the other will reveal. In Western literature, it is suggested to distinguish between the term hacker (hacker), which is proposed to designate a high-level computer professional who is not involved in illegal activities, and a cracker (cracker) - that is, a hacker who uses his abilities to hack computer systems for selfish purposes.
Anyone can be a computer criminal. The typical computer criminal is not a young hacker using his phone and home computer to gain access to large computers. The typical computer criminal is an employee who is allowed access to a system of which he is a non-technical user.
In the US, computer crimes committed by employees account for 70-80 percent of annual computer-related losses. The remaining 20 percent comes from the actions of dishonest and disgruntled employees.
And they do it for a number of reasons:
personal or financial gain
entertainment
Trying to win someone over
self-expression
· accident
vandalism.
1. Computer crimes
Computer crimes have become so widespread in countries with a developed telecommunications infrastructure that special offenses have been introduced into the criminal law to combat them. However, in all countries of the world there is an avalanche-like growth of computer crime. The annual economic damage from such crimes in the USA alone is about 100 billion dollars, and many losses are not detected or reported due to the high latency (secrecy) of these crimes (90%). The data on Russia published in the mass media are less "spectacular", but even they are alarming.
Thanks to the efforts of hackers, "electronic hacking" from the Internet is now a fairly typical precedent, although not always malicious.
In this regard, computer hackers are combined into several groups:
· "inquisitive" hackers are often students "traveling" on the Internet,
· Specialists, thirsting for professional self-affirmation - all sorts of experimenters and researchers.
People who have specific commercial, intelligence or other interests.
burglars and saboteurs. Their goal is to destroy databases, paralyze work, disable computer networks.
Computer crimes are divided into seven main categories, one way or another related to hacking: financial theft, sabotage, hardware theft, software theft, information theft and electronic espionage. And the seventh "crime" is computer hacking.
Money theft. Financial theft occurs when computer records are altered in order to embezzle someone else's money. This is often done through a program that directs money to a specific bank account, usually using the "salami" technique. "Salami" is a method that involves stealing small amounts over a long period of time in the hope that it will not be noticed. Thieves reprogram a bank or some other computer so that money goes into fake accounts. For example, the account can store 713.14863, where 863 are random numbers, since all signs are taken into account when multiplying. Normally the computer will show that the person has $713.15 in the pot by rounding 4 to 5. However, the computer programmed with "salami" separates these extra numbers and places them in separate accounts. And now the person has only $713.14, and hardly anyone will notice it.
The computer itself cannot produce money, it can only transfer legal money to an illegal account. Such thefts are quite difficult to detect. As soon as the thief accumulates a fairly large amount on the account, he withdraws the money from the account and, in most cases, is deleted along with them. Many thieves have tried this form of bank robbery and many have been caught, but now anyone can do it. You can identify the use of such a technique in the following way: a list of all accounts is created on the computer, indicating how many times the account was accessed within one or several days. Then, any account that is requested too often is checked to determine how much money was withdrawn from it during each call. If this amount is small, then someone is lucky. But the mistake these thieves make is that instead of reprogramming the computer to transfer small amounts into an account, they should have simply subtracted that money and kept track of how much money accumulated in an area separate from the account files. Then the parts of the program that print out the total number of bank deposits are modified to account for the hidden amount so that this money does not appear to be lost. When the hidden number reaches a certain value, only then should it be transferred to the thief's account, and the transferred amounts should be equal to random values in order to avoid suspicion. These steps require access to a computer. Usually they are made by bank employees. If such theft is committed by an employee with a limited access level or a non-bank employee, then hacking is necessary.
Sabotage. Computer sabotage is the physical destruction of hardware or software, or the distortion or destruction of information contained in a computer. The reason for sabotage may be the desire to get rid of a competitor or to obtain insurance. Computer hacking is only indirectly related to sabotage. Reverse social engineering uses something like sabotage, but it's really just a temporary and easily fixable computer crash. Computer vandals often sabotage information stored on computers by first using hacker methods to gain access to them. But don't confuse vandals and other data saboteurs with hackers. These people enter false information into computer systems, corrupting databases in one way or another.
Other types of theft. May include theft of hardware or the computer itself and peripherals, as well as theft of computer designs. They are classified as hacking insofar as a stolen computer can be used to obtain access codes. In the case of software piracy, a hacker may secretly read a developer's email or files in an attempt to steal new ideas. Software theft, or software piracy, is the illegal copying of copyrighted software. Hackers often make copies of programs found on a computer system for themselves in order to understand how they work. When it comes to hardware theft, there is a desire to catch up with the competition in software development. Information theft includes the theft of credit cards, lab results, patient or customer data, and generally any data of potential value. Electronic espionage is the sale of such information to a third party when the hacker starts spying on another company or country. In both cases, a hacker technician is installed to steal information and sometimes to contact the spy agency.
Hacking. Hackers are capable of committing any of the above crimes, but many people break into other people's computer systems out of a desire for knowledge - this is the so-called "pure" hacking. Yet many hackers, even the best of them. contributed to the bad reputation of hacking, as they were driven by other motives than gaining knowledge. There are also destructive hackers, and those who simply cannot stop and exit the game in time.
2. Viruses and the fight against them
The main difficulty that arises when trying to give a strict definition of a virus is that almost all the distinguishing features of a virus (introduction into other objects, secrecy, potential danger, etc.) are either inherent in other programs that are in no way viruses, or there are viruses. , which do not contain the above distinctive features (with the exception of the possibility of distribution). For example, if stealth is taken as the distinguishing characteristic of a virus, then it is easy to give an example of a virus that does not hide its spread. Such a virus, before infecting any file, displays a message stating that there is a virus in the computer and this virus is ready to infect the next file, then displays the name of this file and asks the user for permission to inject the virus into the file.
If the ability to destroy programs and data on disks is given as a distinguishing feature of a virus, then as an example of this distinguishing feature you can cite dozens of completely harmless viruses that, apart from their distribution, do not differ in anything else.
The main feature of computer viruses - the possibility of their spontaneous introduction into various objects of the operating system - is inherent in many programs that are not viruses.
The second difficulty that arises when formulating a definition of a computer virus is that this definition must be tied to the specific operating system in which this virus is distributed. For example, theoretically, there may be operating systems in which the presence of a virus is simply impossible. An example of this would be a system where it is forbidden to create and modify areas of executable code, i.e. it is forbidden to modify objects that are either already running or can be run by the system under any conditions. Therefore, it seems possible to formulate only a mandatory condition for a certain sequence of executable code to be a virus.
A mandatory property of a computer virus is the ability to create duplicates of itself (not necessarily identical to the original) and inject them into computer networks and/or files, computer system areas and other executable objects. At the same time, duplicates retain the ability to further distribution.
Who writes viruses? Most of them are created by students and schoolchildren who have just learned assembly language, want to try their hand, but cannot find a more worthy application for them. It is gratifying that a significant part of such viruses is often not distributed by their authors, and the viruses "die" after a while along with the diskettes on which they are stored. Such viruses are most likely written only for self-affirmation.
The second group is also made up of young people (more often students) who have not yet fully mastered the art of programming, but have already decided to devote themselves to writing and distributing viruses. The only reason pushing such people to write viruses is an inferiority complex, which manifests itself in computer hooliganism. From the pen of such "craftsmen" often come either numerous modifications of "classical" viruses, or extremely primitive viruses with a large number of errors. The life of such virus writers has become much easier after the release of virus constructors, with which you can create new viruses even with minimal knowledge of the operating system and assembler, or even having no idea about it at all. Their life has become even easier after the advent of macro viruses, because instead of the complex Assembly language, it is enough to learn a fairly simple BASIC to write macro viruses. Having become older and more experienced, but never matured, many of these virus writers fall into the third, most dangerous group that creates and releases "professional" viruses into the world. These very carefully designed and polished programs are created by professional, often very talented programmers. Such viruses often use quite original algorithms, undocumented and little-known ways to penetrate system data areas.
"Professional" viruses are often made using stealth technology and (or) are polymorphic viruses that infect not only files, but also boot sectors of disks, and sometimes Windows and OS / 2 executable files.
The fourth group of virus authors - "researchers" - stands out somewhat separately. This group consists of quite smart programmers who are inventing fundamentally new methods of infecting, hiding, counteracting antiviruses, etc. They also come up with ways to introduce them into new operating systems, virus constructors and polymorphic generators. These programmers write viruses not for the sake of viruses themselves, but rather for the sake of "exploring" the potentials of the "computer fauna". Often the authors of such viruses do not put their creations into practice, but they actively promote their ideas through numerous electronic publications dedicated to the creation of viruses. At the same time, the danger from such "research" viruses does not fall - having fallen into the hands of "professionals" from the third group, new ideas are very quickly implemented in new viruses.
Where do viruses come from? The main source of viruses today is the global Internet. Largest number Virus infections occur when exchanging letters in Word/Office97 formats. The user of an editor infected with a macro virus, without suspecting it, sends infected letters to recipients, who in turn send new infected letters, and so on. Assume that a user is chatting with five recipients, each of whom is also corresponding with five recipients. After sending an infected email, all five computers that received it become infected. Then five more emails are sent from each newly infected computer. One goes back to an already infected computer, and four go to new recipients. Thus, 1+5+20=26 computers are already infected at the second distribution level. If network recipients exchange letters once a day, then by the end of the working week (in 5 days) at least 1+5+20+80+320=426 computers will be infected. It is easy to calculate that over a hundred thousand computers are infected in 10 days! And every day their number will be quadrupled. The described case of the spread of the virus is the most frequently reported by antivirus companies. It is not uncommon for an infected document file or Excel spreadsheet to be included in the mailing lists of commercial information of a large company due to an oversight. In this case, not five, but hundreds or even thousands of subscribers of such mailings suffer, who then send infected files to tens of thousands of their subscribers. Electronic conferences, ftp file servers and BBS "Public" file servers and electronic conferences are also one of the main sources of viruses. Almost every week there is a message that some user has infected his computer with a virus that was taken from a BBS, ftp server or from some electronic conference. In this case, the infected files are often "uploaded" by the virus author to several BBS/ftp or sent to several conferences at the same time, and these files are disguised as new versions of some software (sometimes - under new versions of antiviruses). In the case of a mass distribution of a virus to ftp/BBS file servers, thousands of computers can be affected almost simultaneously, but in most cases DOS or Windows viruses are "laid", the spread rate of which in modern conditions is much lower than macro viruses. For this reason, such incidents almost never end in mass epidemics, which cannot be said about macro viruses.
Local networks. The third way of "rapid infection" is local networks. If the necessary protection measures are not taken, then an infected workstation infects one or more service files on the server when entering the network (in the case of Novell NetWare, LOGIN.COM). The next day, users launch infected files when they enter the network. Instead of the LOGIN.COM service file, various software installed on the server, standard template documents or Excel spreadsheets used in the company, etc. can also act.
Pirated software. Illegal copies of software, as it has always been, is one of the main "risk areas". Often pirated copies on floppy disks and even on CDs contain files infected with various types of viruses. computer crime virus password
Personal computers "general use". Computers installed in educational institutions also pose a danger. If one of the students brought a virus on his floppy disks and infected any educational computer, then the floppy disks of all other students working on this computer will also receive another "infection". The same applies to home computers if more than one person works on them. It is not uncommon for a student son (or daughter), working on a multi-user computer at an institute, to drag a virus from there to a home computer, as a result of which the virus enters the computer network of the father's or mother's company.
Repair services. Rarely enough, but it is still quite possible to infect a computer with a virus during its repair or routine inspection.
Repairmen are people too, and some of them tend to give a damn about the elementary rules of computer security. Once forgetting to close the write protection on one of his floppy disks, such a "maestro" will quickly spread the infection on the machines of his clientele and, most likely, will lose it (the clientele).
2.1 Choosing a protection system
Any computer system is not perfect, that is, it cannot completely ensure the security of data on your PC. In order to 100% protect data from falling into the wrong hands, it is necessary to destroy it. And to keep the contents of your computer intact, you need to find a compromise between the importance of the data you protect and the inconvenience associated with the use of protection measures. Security measures are measures introduced by management to ensure the security of information - administrative guidance documents (orders, regulations, instructions), hardware devices or additional programs - the main purpose of which is to prevent crime and abuse from occurring.
Protective measures can also serve as a limitation, reducing the amount of damage from a crime. End-user awareness of security measures provides four levels of protection for computer and information resources:
· Detection - provides early detection of crimes and abuses, even if protection mechanisms have been bypassed.
Restriction - the amount of losses is reduced if the crime did occur, despite measures to prevent and detect it
· Recovery - Efficient recovery of information is ensured with documented and proven recovery plans.
The choice of means of protection should be based on providing sufficient security and at the same time not cause inconvenience. Each user must make their own risk analysis and decide which protection measures are most appropriate for their particular case.
Risk analysis for personal computers can be divided into three classes: analysis of autonomous systems, that is, a single computer, analysis of local systems and analysis of remote access systems connected to a global network (eg Internet).
2.2 Use of passwords
The idea behind using passwords is this: if someone tries to access your data or hardware, then passwords should create a lot of inconvenience. The more difficult it is to guess or "crack" the password you use, the more secure your data will be. The length of the password significantly affects the level of protection. Personal numbers are by far one of the least secure passwords in widespread use (eg credit cards for ATM cash registers or calling cards). In personal numbers, numbers from 0 to 9 can be used, that is, the number can have ten thousand variations. This is enough if we are talking about a person standing near the ATM and typing a code at random, but not much if we are talking about a computer using the frontal solution method.
In a "frontal" attack, all possible combinations of passwords are checked until one of them works. As the password length increases, the difficulty of a frontal attack increases, as it will take longer. Of course, many banks use not only a four-digit code (PIN), but also other methods to improve security, such as video cameras and ATMs that block cards. At the same time, the protection measures in each bank are very different. Most banks also provide the following service: you can call the bank, dial the card number and personal number and find out the status of the current account. This scenario makes your personal number (PIN) vulnerable - someone can sit down at the phone and try different options.
The four-digit password - your PIN - has a total of 9999 possible combinations. However, most computer passwords are longer and can contain characters in addition to the numbers 1-9. A four-digit password, which uses numbers and symbols, is more difficult to decipher - it can contain 1679616 unique combinations. Here is the formula for calculating the possible number of character combinations: c=xy, where c is the number of possible combinations, x is the number of different characters used in each position of the password, y is the number of characters in the password. For example, when using PIN c=104. Also, some passwords are case sensitive and include punctuation marks, so the number of possible combinations is even higher. In addition to the passwords used to access the local network, the Internet, etc., computer users have a number of security measures that include passwords. These include BIOS-based protection that requires you to enter a password when you boot your computer, special security software that blocks access to individual files, and password-protected ZIP archive files.
2.3 Email protection
The vast majority of e-mail is sent over the Internet or other wide area networks in plain text that can be read. The Electronic Communications Privacy Act treats your email as a regular phone call. You must understand that system administrators have all the necessary tools to read e-mail on their system. Sometimes they even need to check email to make sure the system is working properly.
Hackers and pryers differ in that they own different ways gaining access to your mail, but both of these categories cannot read your mail if it is encrypted. If you need to protect sensitive information, use PGP (Pretty Good Privacy) to encrypt mail before sending.
2.4 Use of encryption - cryptography
Cryptographic methods for protecting information in automated systems can be used both to protect information processed in a computer or stored in various types of memory, and to close information transmitted between various elements of the system via communication lines. But why has the problem of using cryptographic methods in information systems (IS) become particularly relevant at the moment? On the one hand, the use of computer networks has expanded, in particular the global Internet, through which large amounts of information of a state, military, commercial and private nature are transmitted, which does not allow unauthorized persons to access it. On the other hand, the emergence of new powerful computers, network and neural computing technologies made it possible to discredit cryptographic systems, which until recently were considered practically undisclosed. Cryptography makes it possible to transform information in such a way that its reading (restoration) is possible only if the key is known.
The process of cryptographic closing of data can be carried out both in software and in hardware. The hardware implementation is significantly more expensive, but it also has advantages: high performance, simplicity, security, etc. The software implementation is more practical and allows a certain flexibility in use.
For modern cryptographic information security systems, the following generally accepted requirements are formulated:
The encrypted message must be readable only if the key is present.
number of operations required to determine the used key
Encryption by a fragment of an encrypted message and the corresponding
The plain text must be no less than the total number of possible keys;
The number of operations required to decrypt information by searching through all possible keys must have a strict lower estimate and go beyond the capabilities of modern computers (taking into account the possibility of using network computing);
knowledge of the encryption algorithm should not affect the reliability of protection; a slight change in the key should lead to a significant change in the form of the encrypted message, even when using the same key;
Structural elements of the encryption algorithm must be unchanged;
additional bits introduced into the message during the encryption process must be completely and securely hidden in the ciphertext;
The length of the ciphertext must be equal to the length of the original text;
· there should be no simple and easily established dependence between the keys sequentially used in the encryption process;
any key from the set of possible ones should provide reliable protection of information;
The algorithm should allow both software and hardware implementation, while changing the key length should not lead to a qualitative deterioration of the encryption algorithm.
The simplest criterion for the effectiveness of cryptographic systems is the probability of revealing a key or the power of a set of keys. In essence, this is the same as cryptographic strength. For its numerical evaluation, one can also use the complexity of deciphering the cipher by enumeration of all keys.
2.5 Antivirus programs
Ways to counteract computer viruses can be divided into several groups: prevention of virus infection and reduction of the expected damage from such infection; methods of using anti-virus programs, including the neutralization and removal of a known virus; ways to detect and remove an unknown virus. Antivirus programs are the most effective in combating computer viruses. Modern anti-virus programs are multifunctional products that combine both preventive and prophylactic tools, as well as virus treatment and data recovery tools.
Classification of antiviruses.
The principle of operation of anti-virus scanners is based on scanning files, sectors and system memory and searching for known and new (unknown to the scanner) viruses in them. So-called "masks" are used to search for known viruses. A virus mask is some constant code sequence specific to that particular virus. If the virus does not contain a permanent mask, or the length of this mask is not large enough, then other methods are used. An example of such a method is an algorithmic language that describes all possible code variants that can be encountered when this type of virus is infected. This approach is used by some antiviruses to detect polymorphic viruses. Many scanners also use "heuristic scanning" algorithms, i. analysis of the sequence of commands in the scanned object, collecting some statistics and making a decision ("probably infected" or "not infected") for each scanned object. Since heuristic scanning is largely a probabilistic method for detecting viruses, many laws of probability theory apply to it. For example, the higher the percentage of detected viruses, the greater the number of false positives.
Blockers. Anti-virus blockers are resident programs that intercept "virus-dangerous" situations and notify the user about it. "Virus-dangerous" calls include calls to open for writing to executable files, writing to the boot sectors of disks or the MBR of a hard drive, attempts by programs to remain resident, etc., that is, calls that are typical for viruses at the time of reproduction. The advantages of blockers include their ability to detect and stop the virus at the earliest stage of its reproduction, which, by the way, is very useful in cases where a well-known virus constantly "creeps out of nowhere". The disadvantages include the existence of ways to bypass blocker protection and a large number of false positives, which, apparently, was the reason for the almost complete refusal of users from this kind of anti-virus programs (for example, I am not aware of any blocker for Windows95 / NT - there is no demand, no offer).
Immunizers.
Immunizers are divided into two types: immunizers that report infection, and immunizers that block infection with any type of virus. The first ones are usually written to the end of files (according to the principle of a file virus) and each time the file is launched, it is checked for changes. The disadvantage of such immunizers is only one, but it is lethal: the absolute inability to report infection with a stealth virus. Therefore, such immunizers, as well as blockers, are practically not used at present. The second type of immunization protects the system from attack by a particular type of virus. The files on the disks are modified in such a way that the virus assumes they are already infected (for example, the infamous "MsDos" string that protects against the "Jerusalem" fossil virus). To protect against a resident virus, a program that imitates a copy of the virus is entered into the computer's memory. When launched, the virus stumbles upon it and believes that the system is already infected.
This type of immunization cannot be universal, since it is impossible to immunize files against all known viruses: some viruses consider files already infected if the file creation time contains a mark of 62 seconds, and others - 60 seconds. However, despite this, such immunizers as a half measure can quite reliably protect a computer from a new unknown virus until the moment when it is detected by anti-virus scanners.
If a virus is indeed found on the computer, then you need to do the following: if a file virus is detected, if the computer is connected to the network, you must disconnect it from the network and inform the system administrator. If the virus has not yet penetrated the network, this will protect the server and other workstations from the virus. If the virus has already hit the server, then disconnecting from the network will not allow it to re-enter the computer after it has been cured. Connection to the network is possible only after all servers and workstations are cured. If a boot virus is detected, the computer should not be disconnected from the network: viruses of this type do not spread over the network (naturally, except for file-boot viruses). If a macro virus infection has occurred, instead of disconnecting from the network, it is enough to make sure that the corresponding editor (Word / Excel) is inactive on any computer for the period of treatment. If a file or boot virus is detected, you should make sure that the virus is either non-resident or the resident part of the virus is neutralized: when launched, some (but not all) antiviruses automatically neutralize the resident viruses in memory. Removing the virus from memory is necessary in order to stop its spread. When scanning files, antiviruses open them, many of the resident viruses intercept this event and infect the files being opened. As a result, most of the files will be infected, because the virus is not removed from memory. The same can happen in the case of boot viruses - all floppy disks being checked may be infected.), so you should also check the "boot sequence A: C:" item in the BIOS settings to ensure that DOS is loaded from the system floppy disk, and not from an infected hard drive . In addition to residency/non-residency, it is useful to familiarize yourself with other characteristics of a virus: the types of files infected by the virus, manifestations, and so on. The only source of detailed information of this kind known to me about almost all known viruses is the AVP Virus Encyclopedia.
Using an antivirus program, you need to restore infected files and then check their performance. Before disinfection or at the same time - create backup copies of infected files and print or save somewhere a list of infected files (antivirus log file). This is necessary in order to restore files if the disinfection fails due to an error in the anti-virus disinfection module or because the anti-virus is unable to disinfect the given virus. In this case, you will have to resort to the help of some other antivirus. It is much more reliable, of course, to restore infected files from a backup copy (if any), but you will still need antivirus services - in case not all copies of the virus are destroyed, or if the files in the backup copy are also infected. It should be noted that the quality of file recovery by many antivirus programs leaves much to be desired. Many popular antiviruses often irreversibly damage files instead of curing them. Therefore, if the loss of files is undesirable, then the above points should be followed in full. In the case of a boot virus, all floppy disks must be scanned, whether they are bootable (that is, contain DOS files) or not. Even a completely empty floppy disk can become a source of virus spread - just forget it in the disk drive and restart the computer (unless, of course, the floppy disk is marked as the boot disk in BIOS Setup). LZEXE, PKLITE or DIET, files in archives (ZIP, ARC, ICE, ARJ, etc.) and data in self-extracting files created by utilities like ZIP2EXE. If you accidentally pack a file infected with a virus, then it is almost impossible to detect and remove such a virus without unpacking the file.
In this case, a typical situation will be when all anti-virus programs that are unable to scan inside packed files will report that all disks have been cleaned of viruses, but after a while the virus will appear again. Virus strains can also infiltrate backup copies of software when updating these copies. Moreover, archives and backup copies are the main suppliers of long-known viruses. A virus can "sit" in a distribution copy of a software product for years and suddenly appear when installing programs on a new computer. No one guarantees the complete destruction of all copies of a computer virus, since a file virus can infect not only executable files, but also overlay modules with name extensions other than COM or EXE. A boot virus can remain on a floppy disk and suddenly appear when you accidentally try to reboot from it. Therefore, it is advisable for some time after the removal of the virus to constantly use the resident anti-virus scanner (not to mention the fact that it is desirable to use it all the time).
List of used literature
1. Magazine "Home Computer" - No. 10, 2001.
2. S. Simonovich, G. Evseev "The latest tutorial on working on the Internet" - M: "DESS COM", 2000 - 528 p.
3. S. Simonovich "Computer science for lawyers and economists" M: "Infocom-Press", 2001.
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