nyuuzyou/kompy huggingface dataset:
Figure 21.16 IEEE 802.11 MAC frame format

744
21 Wireless Local Area Networks
The
sequence control ﬁ eld
is a 16-bit ﬁ eld that consists of two subﬁ elds.
The subﬁ elds are a 4-bit fragment number and a 12-bit sequence number. This
ﬁ eld is used to allow a receiving station to eliminate duplicate received frames.
The
sequence number subﬁ eld
contains numbers assigned sequentially by the
sending station to each MSDU. This sequence number is incremented after each
assignment and wraps back to zero when incremented from 4095. The sequence
number for a particular MSDU is transmitted in every data frame associated with
the MSDU. It is constant over all transmissions and retransmissions of the MSDU.
If the MSDU is frangmented, the sequence number of the MSDU is sent with
each frame containing a fragment of the MSDU. The
fragment number subﬁ eld
contains a 4-bit number assigned to each fragment of an MSDU. The ﬁ rst, or
only, fragment of an MSDU is assigned a fragment number of zero. Each succes-
sive fragment is assigned a sequentially incremented fragment number. The frag-
ment number is constant in all transmissions or retransmissions of a particular
fragment.
The
frame body ﬁ eld
contains the information speciﬁ c to the particu-
lar data or management frames. This ﬁ eld is variable in length. It may be as
long as 2034 bytes without encryption, or 2312 bytes when the frame body is
encrypted. The value of 2304 bytes as the maximum length of this ﬁ eld was cho-
sen to allow an application to send 2048-byte pieces of information, which can be
encapsulated by as many as 256 bytes of upper layer protocol headers and
trailers.
The
frame check sequence (FCS) ﬁ eld
is 32 bits in length. It contains the
result of applying the C-32 polynomial to the MAC header and frame body.
The original 802.11 standard suffers from some serious limitations which
prevent it from becoming a leading technology and a serious alternative to wired
LAN. The following are some of the problems:
Low data rate: The 802.11 protocol imposes very high overhead to all packets
that reduce real data rate signiﬁ cantly
No QoS guarantees
Several extensions to the basic 802.11 standard have been introduced by
IEEE to provide higher data rates or QoS guarantees. 802.11a, 802.11b, and
802.11g focus on higher data rates whereas 802.11e is aimed at providing QoS
guarantees.
IEEE 802.11 WLAN - Wireless Local Area Networks

742
21 Wireless Local Area Networks
BO
backoff time (
s)
DIFS
distributed inter-frame space (50
s)
PLCP
time required to transmit physical layer convergence protocol (
s)
RTS
request to send frame size (bits)
CTS
clear to send frame size (bits)
D
frame size (bits)
A
acknowledgement frame size (bits)
R
channel bit rate (bits per second)
SIFS
short inter-frame space (10
s)
We refer to Figure 21.15b and assume that node B and C intend to transmit
data only without receiving data. When node C is transmitting data to node D,
node B is aware of the transmission. This is because node B is within the radio
coverage of node C. Without exchanging RTS and CTS frames, node B will not
initiate data transmission to node A because it will detect a busy medium. The
transmission between node A and node B, therefore, is blocked even if both of
them are idle. This is referred as the
exposed node problem
. To alleviate this prob-
lem, a node must wait a random backoff time between the two consecutive new
packet transmission times.
21.5.5 IEEE 802.11 MAC Sublayer
In IEEE 802.11, the MAC sublayer is responsible for asynchronous data service
(e.g., exchange of MAC service data units (MSDUs)), security service (conﬁ denti-
ality, authentication, access control in conjunction with layer management), and
MSDU ordering.
A
B
1. RTS
1. RTS
2. CTS
2. CTS
C
D
CTS : Clear to Send
RTS : Request to Send
(b)
Figure 21.15(b) Hidden and exposed node problem

The MAC sublayer accepts MSDUs from higher layers in the protocol stack
to send them to the equivalent layer of the protocol stack in another station. The
MAC adds information to the MSDU in the form of headers and trailers to gener-
ate a MAC protocol data unit (MPDU). The MPDU is then passed to the physical
layer to be sent over the wireless medium to other stations. The MAC may frag-
ment MSDUs into several frames to increase the probability of each individual
frame being delivered successfully. The MAC frame contains addressing informa-
tion, information to set the network allocation vector (NAV), and a frame check
sequence to verify the integrity of the frame. The general IEEE 802.11 MAC
frame format is shown in Figure 21.16.
The MAC frame format contains four address ﬁ elds. Any particular frame
type may contain one, two, three, or four address ﬁ elds. The address format in
IEEE 802.11-1997 is a 48-bit address, used to identify the source and destination
of MAC addresses contained in a frame, as IEEE 802.3. In addition to source
address (SA) and destination address (DA), three additional address types are
deﬁ ned: the transmitter address, the receiver address (RA), and the basic service
set identiﬁ er (BSSID). The BSSID is a unique identiﬁ er for a particular basic ser-
vice set of the IEEE 802.11 WLAN. In an infrastructure basic service set, the
BSSID is the MAC address of the AP.
The
transmitter address
is the address of the MAC that transmitted the
frame onto the wireless medium. This address is always an individual address.
The transmitter address is used by stations receiving a frame to identify the station
to which any responses in the MAC frame exchange protocol will be sent.
The
receiver address
(
RA
) is the address of the MAC to which the frame is
sent over the wireless medium. This address may be either an individual or group
address.
The
source address
(
SA
) is the address of the MAC that originated the frame.
This address is always an individual address.This address does not always match
the address in the transmitter address ﬁ eld because of the indirection that is per-
formed by the distribution system of an IEEE 802.1 WLAN. It is the SA ﬁ eld that
should be used to identify the source of a frame when indicating that a frame has
been received to higher layer protocols.
The
destination address
(
DA
) is the address of the ﬁ nal destination to which
the frame is sent. This address may be either an individual or group address.
This address does not always match the address in the RA ﬁ eld because of the
indirection that is performed by the DS.
MAC Header
Frame
Control
Duration/
ID
Address
2
Address
1
Address
3
Sequence
Control
Address
4
Frame
Body
FCS
Security of IEEE 802.11 Systems

|
Security of IEEE 802.11 Systems Pdf ko'rish
|
bet | 31/55 | Sana | 24.05.2024 | Hajmi | 343,31 Kb. | | #252539 |
Bog'liq garg200721.7 Security of IEEE 802.11 Systems
The IEEE 802.11 provides for MAC access control and encryption mechanisms.
Earlier, the
wireline equivalent privacy
(WEP) algorithm was used to encrypt mes-
sages. WEP uses a Rivest Cipher 4 (RC4) pseudo-random number generator with
two key structures of 40 and 128 bits. Because of the inherent weaknesses of
the WEP, the IEEE 802.11i committee developed, a new encryption algorithm
(see Chapter 13) and worked on the enhanced security and authentication mecha-
nisms for 802.11 systems.
For access control, ESSID (also known as a WLAN service area ID) is pro-
grammed into each AP and is required knowledge in order for a wireless client to
associate with an AP. In addition, there is provision for a table of MAC addresses
called an
access control list
to be included in the AP, restricting access to stations
whose MAC addresses are not on the list.
Beyond layer 2, 802.11 WLANs support the same security standards
supported by other 802 LANs for access control (such as network operating
system logins) and encryption (such as IPSec or application-level encryption).
These higher-level technologies can be used to create end-to-end secure networks
encompassing both wired LAN and WLAN components, with the wireless piece
of the network gaining additional security from the IEEE 802.11i feature set.
21.8 Power
Management
Power management is necessary to minimize power requirements for battery
powered portable mobile units. The standard supports two power-utilization
modes, called
continuous aware mode
and
power save polling mode
. In the
former, the radio is always on and draws power, whereas in the latter, the radio is
dozing with the AP and is queuing any data for it.
A power saver mode or sleep mode is deﬁ ned when the station is not
transmitting in order to save battery power. However, critical data transmissions
cannot be missed. Therefore APs are required to have buffers to queue messages.
|
| |
Joining an Existing Basic Service Set

radio channel to which the AP is set. Periodically it surveys all 802.11 channels in
order to access whether a different AP would provide it with better performance
characteristics. If it determines that this is the case, it reassociates with the new
AP, tuning to the radio channel to which that AP is set. Reassociating usually
occurs because the wireless station has physically moved away from the original
AP, causing the signal to be weakened. In other cases, reassociating occurs due to
changes in radio characteristics in the building, or due to high network trafﬁ c on
the original AP. In the latter case this function is known as load balancing, since
its primary function is to distribute the total WLAN load most efﬁ ciently across
the available wireless infrastructure.
The process of dynamically associating and reassociating with APs allows
network managers to set up WLANs with very broad coverage by creating a series
of overlapping 802.11b cells throughout a building or across a campus. To be
successful, the IT manager ideally will employ channel reuse, taking care to set up
each access point on an 802.11 DSSS channel that does not overlap with a chan-
nel used by a neighboring AP (see Figure 21.17).
As noted above, while there are 14 partially overlapping channels speciﬁ ed
in 802.11 DSSS, there are only 3 channels that do not overlap at all and these are
the best to use for multicell coverage (refer to Table 21.5). If two APs are in range
of one another and are set to the same or partially overlapping channels, they
may cause some interference for one another, thus lowering the total available
bandwidth in the area of overlap.
Tizim arxitekturasi - Fanidan 1- amaliy topshiriq

№
|
|
|
1
|
Ma'lumotlar bo'yicha olimlar
|
Ma'lumotlar olimlari mazmunli tushunchalarni olish va musiqani his-tuyg'ularga moslashtiruvchi modellarni ishlab chiqish uchun foydalanuvchining afzalliklari, tinglash odatlari va hissiy fikr-mulohazalarni o'z ichiga olgan katta ma'lumotlar to'plamini tahlil qiladi. Tavsiya tizimini quvvatlaydigan algoritmlarni yaratish uchun ular mashinani o'rganish va ma'lumotlarni tahlil qilish usullaridan foydalanadilar.
|
2
|
Musiqashunoslar
|
Musiqa nazariyasi va tarixi bo'yicha o'zlarining tajribalari bilan musiqashunoslar musiqaning hissiy xususiyatlarini aniqlash va tasniflashda hal qiluvchi rol o'ynaydi. Ular qo'shiqlarni turli xil hissiy o'lchovlar asosida tasniflash va tasniflashda yordam beradi, bu esa tavsiyalar tizimiga asosli takliflar berish imkonini beradi.
|
3
|
Dasturiy ta'minot muhandislari
|
Dasturiy ta'minot muhandislari tavsiyalar tizimini ishlab chiqish va saqlashning texnik jihatlari bilan shug'ullanadilar. Ular infratuzilmani quradilar, ma'lumotlarni qayta ishlash quvurlarini boshqaradilar va samarali va aniq musiqa tavsiyalarini ta'minlash uchun ma'lumotlar olimlari tomonidan taklif qilingan algoritmlar va modellarni amalga oshiradilar.
|
4
|
Foydalanuvchi tajribasi (UX) dizaynerlari
|
UX dizaynerlari musiqa tavsiya qilish tizimining foydalanuvchi interfeysi va umumiy foydalanuvchi tajribasiga e'tibor qaratadilar. Ular his-tuyg'ularga asoslangan tavsiyalar qulay va intuitiv tarzda taqdim etilishini ta'minlaydi, bu foydalanuvchilarga tavsiya etilgan musiqaga osongina kirish va undan zavq olish imkonini beradi.
|
5
|
Sifat kafolati (QA) sinovchilari
|
QA sinovchilari tavsiyalar tizimining aniqligi va ishlashini tekshirish uchun javobgardir. Ular tavsiyalardagi har qanday muammo yoki nomuvofiqlikni aniqlash uchun keng qamrovli test o'tkazadilar, bu tizim tegishli va hissiy jihatdan uyg'un musiqa takliflarini yetkazib berishini ta'minlaydi.
|
part is to segment packets received from the SSCS, and reassemble segmented

The DLC scheduling algorithm deals with the properties of the HIPERLAN/2
radio access that are dependent on ARQ and link adaptation. ARQ reacts on trans-
mission errors and initiates retransmission. When the error check bit detects error(s)
in the transmission, ARQ sends a request for retransmission of the error packet
data unit (PDU). Thus, for a poor radio link, retransmission will cause large trans-
mission delay. Selective repeat ARQ uses a transmission window at the transmitter
and receiver. The receiver notiﬁ es the transmitter of the sequence number below
which all PDUs are received correctly and points out which PDU is not correct.
Based on the current radio link conditions, the link adaptation in the DLC
layer assigns a speciﬁ c PHY mode to the PDU dedicated to a connection. Each con-
nection and its direction are addressed individually and the assignment varies from
one MAC frame to another. The link adaptation scheme adapts the PHY mode
based on link quality measurements. ARQ and link adaptation reduce packet loss
rate but introduce additional overhead and delay to the radio access system.
Total system throughput, transmission delay, and bit error rate are the
important parameters in determining the performance of the HIPERLAN/2 radio
access. There is a strong interaction between PHY modes and these parameters.
The MAC protocol functions are used for organizing the access and
transmission of data on the radio link. Since HIPERLAN/2 uses a central resource
Rasmdagi reduktorni nomini yozing

|
Rasmdagi reduktorni nomini yozing
|
bet | 15/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariRasmdagi reduktorni nomini yozing. chervyagi pastda joylashgan chervyakli reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. chervyagi pastda joylashgan chervyakli reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing chervyagi pastda joylashgan chervyakli reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. qopqog‘i ajratilgan chervyagi pastda joylashgan chervyakli reduktorning umumiy ko‘rinishi
Yassi tasmali uzatmada yetaklovchi shkiv uchun P1 = 4,0 kVt, n1 = 720 ayl/daq berilgan bo„lsa, burovchi momentini aniqlang 53,07 Nm
. Yassi tasmali uzatmada yetaklovchi shkivning diametri 150 mm bo„lsa va uzatish soni 2,5 ga teng bo„lsa, u holda yetaklanuvchi shkiv diameptrini aniqlang. 375 mm
Lentali konveer uchun bir pog„onali silindrsimon uzatmaning ishlash muddati Z = 11 yil, Ksut=0,7 va Kyil=0,5 ga teng bo„lsa, yuritmaning umumiy ish vaqtini aniqlang 33726 soat
Bir pog„onali silindrsimon reduktorning shesternyasi uchun tanlab olingan materialning qattiqligi НВ1=269 .. 302 ga teng bo„lsa, kontakt chidamlilik cheshgarasini aniqlang. 571 Mpa
Bir pog„onali silindrsimon reduktorning tishli g„ildirak uchun tanlab olingan materialning kontakt chidamlilik cheshgarasi 615 MPa ga teng bo„lsa, tanlab olingan materialning o„rtacha qattiqligini aniqlang. 272,5 Mpa
Bir pog„onali silindrsimon reduktorning tishli g„ildirak uchun tanlab olingan materialning tish yegilishiga chidamlilik cheshgarasi 630 MPa ga teng bo„lsa, tanlab olingan materialning o„rtacha qattiqligini aniqlang. 350 Mpa
Bir pog„onali silindrsimon reduktorning shesternyasi uchun tanlab olingan materialning qattiqligi НВ1=269 .. 302 ga teng bo„lsa, tish yegilishiga chidamlilik cheshgarasini aniqlang. 514 Mpa
|
| |
Yuritmaning elekrodvigateling quvvati 8,6 kVt vaetaklovchi valning burovchi momenti 76,2 Nm ga teng bo‟lsa, aylanish chastotsini aniqlang

|
Yuritmaning elekrodvigateling quvvati 8,6 kVt vaetaklovchi valning burovchi momenti 76,2 Nm ga teng bo‟lsa, aylanish chastotsini aniqlang
|
bet | 13/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblari. Yuritmaning elekrodvigateling quvvati 8,6 kVt vaetaklovchi valning burovchi momenti 76,2 Nm ga teng bo‟lsa, aylanish chastotsini aniqlang. 112,86 rad/s
Rasmdagi reduktorni nomini yozing. bir pog‘onali silindrsimon uzatmali gorizontal reduktorning kinematik sxemasi
Rasmdagi reduktorni nomini yozing. bir pog‘onali silindrsimon uzatmali gorizontal reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. bir pog‘onali silindrsimon uzatmali vertikal reduktorning kinematik sxemasi
Rasmdagi reduktorni nomini yozing. bir pog‘onali silindrsimon uzatmali vertikal reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing bir pog‘onali konussimon uzatmali gorizontal reduktorning kinematik sxemasi
Rasmdagi reduktorni nomini yozing. bir pog‘onali konussimon uzatmali gorizontal reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. bir pog‘onali konussimon uzatmali yetaklanuvchi vali vertikal joylashgan reduktorning kinematik sxemasi
Rasmdagi reduktorni nomini yozing. bir pog‘onali konussimon uzatmali yetaklanuvchi vali vertikal joylashgan reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. ikki pog‘onali silindrsimon uzatmali gorizontal reduktorning kinematik sxemasi
Rasmdagi reduktorni nomini yozing. ikki pog‘onali silindrsimon uzatmali gorizontal reduktorning umumiy ko‘rinishi
. Rasmdagi reduktorni nomini yozing. ikki pog‘onali silindrsimon uzatmali gorizontal reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. ikki pog‘onali qiya tishli g‘ildirakli silindrsimon uzatmali gorizontal reduktorning umumiy ko‘rinishi
Rasmdagi reduktorni nomini yozing. ikki pog‘onali qiya tishli g‘ildirakli silindrsimon uzatmali gorizontal reduktorning umumiy ko‘rinishi
|
|
Bosh sahifa
Aloqalar
Bosh sahifa
Yuritmaning elekrodvigateling quvvati 8,6 kVt vaetaklovchi valning burovchi momenti 76,2 Nm ga teng bo‟lsa, aylanish chastotsini aniqlang
|
Mashina detallari kursining vazifasi nimalardan iborat? - bet 18

|
Mashina detallari kursining vazifasi nimalardan iborat?
|
bet | 18/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariTo„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada tishlarning yig„indisi 250 va uzatish soni 4 ga teng bo„lsa, uzatmaning tishli g„ildiragining tishlar sonini aniqlang. 200
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada tishlarning yig„indisi 250 va uzatish soni 4 ga teng bo„lsa, uzatmaning shesternyaning tishlar sonini aniqlang. 50
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada ilashish moduli 5 ga va shesternyaning dastlabki eni 125 ga teng bo„lsa, tishning uzunlik koeffitsientini aniqlang. 25
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada shesternyaning dastlabki eni 1 00 va tishning uzunlik koeffitsientini 20 ga teng bo„lsa, ilashish modulini aniqlang. 5
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada g„ildirakning aylana tezligi 1,5 m/s va bo„luvchi aylana diametri 150 mm ga teng bo„lsa, g„ildirak valining burchak tezligini aniqlang. 20 rad/s
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada g„ildirak valining burchak tezligi 25 rad/s va bo„luvchi aylana diametri 250 mm ga teng bo„lsa, g„ildirakning aylana tezligini aniqlang. 3,125 m/s
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada g„ildirak valining aylanish chastotasi 100 ayl/min va bo„luvchi aylana diametri 250 mm ga teng bo„lsa, g„ildirakning aylana tezligini aniqlang? 1,3 m/s
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada g„ildirakning eni 64 mm ga teng bo„lsa, shestrenyaning eni qanday o„lchamda bo„lishi lozim. 66 va 70 mm oralig‘ida
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada g„ildirakning eni 80 mm, uzatish soni 2 ga va Ba=0,4 ga teng bo„lsa, o„qlar aro masofani qiymatini toping. 200mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada g„ildirakning bo„luvchi aylana diametri 100mm, burovchi momenti 2000 Nm ga teng bo„lsa, aylantiruvchi kuchning qiymatini toping. 40 kN
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada шестернясининг тишлар 20, узатиш сони 2, илашиш модули 4, burovchi momenti 250 Nm ga teng bo„lsa, aylantiruvchi kuchning qiymatini toping. 3125 N
|
| |
Rasmlar orasidan buralishga ishlaydigan prujinani toping ?

|
Rasmlar orasidan buralishga ishlaydigan prujinani toping ?
|
bet | 21/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariRasmlar orasidan buralishga ishlaydigan prujinani toping ?
Rasmlar orasidan siqilishga ishlaydigan prujinani toping ?
Rasmlar orasidan cho‘zilishga ishlaydigan prujinani toping ?
Rasmlar orasidan egilishga ishlaydigan prujinani toping ?
Rasmlar orasidan chervyak g‘ildiragini to‘g‘ri toping?
Podshipniklarning yuk ko‘taruvchanligini aniqlash formulasini toping ?
Rasmlar orasidan tarelkasimon prujinani toping?
Rasmlar orasidan konusli spiralsimon prujinani toping?
Rasmlar orasidan uchma-uch payvand birikmani toping?
Rasmlar orasidan ustma-ust payvand birikmani toping?
Rasmlar orasidan burchgakli payvand birikmani toping?
Rasmlar orasidan tavrli payvand birikmani toping?
Rasmlarda ko‘rsatilgan rezbalar orasidan metrik rezbani toping?
Rasmlarda ko‘rsatilgan rezbalar orasidan dyumli rezbani toping?
Detallar birikmalari sxemalari orasidan yashirin kallak vintli birikmani to‘g‘ri toping?
Detallar birikmalari sxemalari orasidan shpilkali birikmani to‘g‘ri toping?
Detallar birikmalari sxemalari orasidan boltli birikmani to‘g‘ri toping?
Detallar birikmalari sxemalari orasidan konturi gaykali birikmani to‘g‘ri toping?
Shponkali birikmani asosiy turlari qanday? Prizmatik, segmentsimon, silindrsimon, ponasimon
Prizmatik shponkalarning eguvchi kuchlanishga aniqlash formulasini toping?
Segmentsimon shponkalarning eguvchi kuchlanishga aniqlash formulasini toping?
|
| |
Tishli uzatmalarning val o‟qlari parallel joylassa bunday uzatma ….. uzatma deb ataladi. Nuqtalar o‟rnini to‟ldiring

|
Tishli uzatmalarning val o‟qlari parallel joylassa bunday uzatma ….. uzatma deb ataladi. Nuqtalar o‟rnini to‟ldiring
|
bet | 12/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariTishli uzatmalarning val o‟qlari parallel joylassa bunday uzatma ….. uzatma deb ataladi. Nuqtalar o‟rnini to‟ldiring silindrsimon
Tishli uzatmalarning val o‟qlari kesuvchan joylassa bunday uzatma ….. uzatma deb ataladi. Nuqtalar o‟rnini to‟ldiring. Konussimon
Tishli uzatmalarning val o‟qlari ayqash uzatma ….. uzatma deb ataladi. Nuqtalar o‟rnini to‟ldiring. Chervyakli
Tishli uzatma- bu ? harakatni bir valdan ikkinchi valga tishli g‘ildiraklar vositasida uzatish mexanizmi
Rasmdagi yurutmaning nomini to‟g‟ri ko‟rsating ? konussimon-silinlrsimon ikki pog’onali reduktor, chiqish qismida ochiq silindrsimon tishli uzatmaga ega yurutma
Ikki pog‟onali reduktorli lentali konveyerli yuritmaning barabaning quvvati P=18 kVt va aylanish tezligi v=1,8 m/s ga teng bo‟lsa, barabanni aylantiruvchi kuching qiymatini aniqlang. 10 kN
Yuritmaning chiqish valining quvvati 10,8 kVt bo‟lsa va yuritma uchun 11 kVt quvvatli elektrodvigatel tanlab olingan bo‟lsa, yuritmaning foydali ish koeffisiyentini aniqlang. 0,982
Ikki pog‟onali reduktorli lentali konveyerli yuritmaning barabaning aylanish tezligi v=0,85 m/s ga va baraban diametric 475 mm ga teng bo‟lsa, barabanni aylanish chastotasini aniqlang. 34,2 ayl/min
Yuritmaning elekrodvigateling quvvati 7,5 kVt va aylanish chastotasi 102 rad/s ga teng bo‟lsa, etaklovchi valning burovchi momentini aniqlang. 73,53 Nm
Ikki pog‟onali reduktorli lentali konveyerli yuritmaning barabaning quvvati P=12,6 kVt va barabanni aylantiruvchi kuching qiymatini Ft=1085 N ga teng bo‟lsa, aylanish tezligini aniqlang. 1,16 m/s
Yuritmaning chiqish valining quvvati 10,8 kVt bo‟lsa va yuritmaning foydali ish koeffitsiyenti 0,96 ga teng bo‟lsa, yuritma uchun hisobiy elektrodvigatel quvvatlini. 11,25 kVt
Ikki pog‟onali reduktorli lentali konveyerli yuritmaning barabaning aylanish hastotasi 125 ayl/min va baraban diametric 785 mm ga teng bo‟lsa, barabanni aylanish tezligini aniqlang. 5,13 m/s
|
| |
Valnining chiqib turgan qismini diametrini aniqlash formulasini

|
Valnining chiqib turgan qismini diametrini aniqlash formulasini
|
bet | 20/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariValnining chiqib turgan qismini diametrini aniqlash formulasini ko‘rsatish?
Val va o‘qlarning xavfsizlik koeffitsenti qiymati qanday hisoblanadi?
Valning sapfasi bo‘yin deb atalishi qaysi rasmda to‘g‘ri ko‘rsatilgan?
Valning sapfasi ship deb atalishi qaysi rasmda to‘g‘ri ko‘rsatilgan?
Valning sapfasi tovon deb atalishi qaysi rasmda to‘g‘ri ko‘rsatilgan?
Sharikli radial podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Sharikli radial-tirak podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Sharikli sferik podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Sharikli tirak podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Rolikli radial podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Rasmlardan ham radial ham o’q bo’ylab yo’nalgan yuklamalarga ishlaydigan podshipnikni ko‘rsating
Rolikli sferik podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Rolikli tirak podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Ignasimon radial podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Ignasimon radial - tirgak podshipnik qaysi rasmda to‘g‘ri ko‘rsatilgan?
Rasmdagi 1 -detalni nomi nima ? tashqi halqa
Rasmdagi 2 -detalni nomi nima ? sperator
Rasmda 3 nima deb ataladi ? rolik
Rasmda 4 nima deb ataladi ? ichki halqa
Nim suyuq ishqalanish deb ataladi
Dumalash podshipniklari rasmlari orasidan konussimon podshipnikni toping …
|
| |
Zanjirli uzatmaning etaklovchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 4 ga teng bo‟lsa?

|
Zanjirli uzatmaning etaklovchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 4 ga teng bo‟lsa?
|
bet | 10/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblari. Zanjirli uzatmaning etaklovchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 4 ga teng bo‟lsa? 23
Zanjirli uzatmaning etaklovchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 2 ga teng bo‟lsa? 25
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 2 ga teng bo‟lsa? 54
. Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 3 ga teng bo‟lsa? 75
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini toping, agar zanjirning uzatish soni 4 ga teng bo‟lsa? 92
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 102 ga va etakovchi yulduzchasining tishlar sonini 24 ga teng bo‟lsa, zanjirning uzatish sonini toping? 4,25
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 75 ga va etakovchi yulduzchasining tishlar sonini 25 ga teng bo‟lsa, zanjirning uzatish sonini toping? 3
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 108 ga va etakovchi yulduzchasining tishlar sonini 54 ga teng bo‟lsa, zanjirning uzatish sonini toping? 2
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 108 ga va zanjirning uzatish sonini 2 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 54
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 100 ga va zanjirning uzatish sonini 4 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 25
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 200 ga va zanjirning uzatish sonini 5 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping?
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 150 ga va zanjirning uzatish sonini 3 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 50
|
| |
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada YF nimani anglatadi. tish tuzilish koeffitsientini

|
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada YF nimani anglatadi. tish tuzilish koeffitsientini
|
bet | 19/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariTo„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada YF nimani anglatadi. tish tuzilish koeffitsientini
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada Bа nimani anglatadi. g'ildirak enini o'qlararo masofaga nisbatan koeffitsiyentini
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada м nimani anglatadi. tishning uzunlik koeffitsiyentini
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada шестерня ва тишли ғилдирак учун материаллар танлашда, нималарга эътибор бериш лозим. shesternya materiali mustahkam bo‘lishi kerak
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada SF nimani anglatadi? eguvchi kuchlanishda xafvsizlik koeffitsientini
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada SН nimani anglatadi? kontakt kuchlanishda xafvsizlik koeffitsientini
Chervyakning boʼluvchi aylana diametrini aniqlash formulasini toping? 𝑑2 = Z2m
Chervyakning tish uchi aylana diametrini aniqlash formulasini toping? 𝑑 a1= 𝑞𝑚 + 2
Chervyakning tish tubi aylana diametrini aniqlash formulasini toping? 𝑑f1 = 𝑑1 − 2,4m
Chervyakli uzatmaning asosiy afzalligi nimadan iborat? Uzatish soni kattaligi
Chervyakli uzatmaning asosiy kamchiligi nimadan iborat? qimmatbaho materialdan tayorlanishi
Konussimon uzatmaning asosiy afzalligi nimadan iborat?harakatni burchak ostida uzatish imkoniyati mavjudligi
Konussimon uzatmaning asosiy kamchiligi nimadan iborat? Tayanchlarga tushadigan kuchning kattaligi
Berilgan javoblarda tekis valni toping?
Berilgan javoblarda pog’onali valni toping?
Berilgan javoblarda tirsakli valni toping?
Berilgan javoblarda egiluvchan valni toping?
|
| |
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 120 ga va zanjirning uzatish sonini 3 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping?

|
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 120 ga va zanjirning uzatish sonini 3 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping?
|
bet | 11/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariZanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 120 ga va zanjirning uzatish sonini 3 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 40
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 140 ga va zanjirning uzatish sonini 2,5 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 46
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 125 ga va zanjirning uzatish sonini 5 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 25
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 75 ga va zanjirning uzatish sonini 3 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 25
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 256 ga va zanjirning uzatish sonini 4 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping? 64
Zanjirli uzatmaning FIK to‟g‟ri birilgan qatorni toping?
Zanjirli uzatmaning o‟qlararo masofasini aniqlash formulasini toping?
Zanjirli uzatmaning uzatish soni u=1†2 oraliqda berilgan bo‟lsa o‟qlararo masofasini aniqlash formulasini toping?
Zanjirli uzatmaning uzatish soni u ≤ 6oraliqda berilgan bo‟lsa o‟qlararo masofasini aniqlash formulasini toping?
Zanjirli uzatmaning zanjiridagi bo‟ginlar soni Lt aniqlash formulasini toping?
Zanjirli uzatmaning o‟qlararo masofasini aniqlash formulasini toping?
Zanjirli uzatmaning aylantiruvchi kuchini aniqlash formulasini toping?
Bir qatorli zanjir uchun mustaxkamlik sharti aniqlash formulasini toping?
To„rtinchi g„ildirakning bir minutdagi aylanishlar sonini hisoblab toping? 500 ayi/min
|
|
Bosh sahifa
Aloqalar
Bosh sahifa
Zanjirli uzatmaning etaklanuvchi yulduzchasining tishlar sonini 120 ga va zanjirning uzatish sonini 3 ga teng bo‟lsa, etakovchi yulduzchasining tishlar sonini toping?
|
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=4, m=2 mm, z 1=20 ga teng bo„lsa, tishli g„ildirakning bo„luvchi aylana diametrini aniqlang

|
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=4, m=2 mm, z 1=20 ga teng bo„lsa, tishli g„ildirakning bo„luvchi aylana diametrini aniqlang
|
bet | 17/22 | Sana | 20.02.2024 | Hajmi | 2,45 Mb. | | #159319 |
Bog'liq yakuniy javoblariTo„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=4, m=2 mm, z 1=20 ga teng bo„lsa, tishli g„ildirakning bo„luvchi aylana diametrini aniqlang 160 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=5, m=2 mm, z1=20 ga teng bo„lsa, tishli g„ildirakning tish uchi aylana diametrini aniqlang. 200 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=5, m=2 mm, z1=20 ga teng bo„lsa, tishli g„ildirakning tish uchi tubi diametrini aniqlang. 195 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada m=4 mm, z1=25 ga teng bo„lsa, shesternyaning bo„luvchi aylana diametrini aniqlang. 100 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada m=4 mm, z1=25 ga teng bo„lsa, shesternyaning tish uchi aylana diametrini aniqlang. 108 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada m=4 mm, z1=25 ga teng bo„lsa, shesternyaning tish uchi tubi diametrini aniqlang. 90 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=4, z1=25 va d1=60 mm ga teng bo„lsa, tishli g„ildirakning tish tubi diametrini aniqlang. 234 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=4 va d1=100 mm ga teng bo„lsa, uzatmaning o„qlararo masofasini aniqlang. 250 mm
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada o„qlararo masofasi 200 va ilashish moduli 2mm va uzatish soni 4 ga teng bo„lsa, uzatmaning shestrenyasining tishlar sonini aniqlang. 40
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada tishli g„ildirakning tish uchi aylana diametri 224 mm va ilashish moduli 4mm va uzatish soni 3 ga teng bo„lsa, uzatmaning shestrenyasining tishlar sonini aniqlang. 18
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada tishli g„ildirakning tish tubi aylana diametri 325 mm va ilashish moduli 5mm va uzatish soni 3 ga teng bo„lsa, uzatmaning shestrenyasining bo„luvchi aylana diametrini aniqlang. 105
|
|
Bosh sahifa
Aloqalar
Bosh sahifa
To„g„ri tishli bir pog„onali silindrsimon g„ildirakli uzatmada u=4, m=2 mm, z 1=20 ga teng bo„lsa, tishli g„ildirakning bo„luvchi aylana diametrini aniqlang
|
IEEE 
802.11n - Wireless Local Area Networks

|
Wireless Local Area Networks Pdf ko'rish
|
bet | 33/55 | Sana | 24.05.2024 | Hajmi | 343,31 Kb. | | #252539 |
Bog'liq garg200721.10 IEEE
802.11n
In response to growing market demand for higher-performance WLANs, the
IEEE formed the task group 802.11n. The scope of this task group is to deﬁ ne
modiﬁ cations to the physical and MAC layer to deliver a minimum of 100 Mbps
throughput at the MAC service access point (SAP).
802.11n employs an evolutionary philosophy reusing existing technologies
where practical, while introducing new technologies where they provide effective
performance improvements to meet the needs of evolving applications. Reuse of
legacy technologies such as OFDM, forward error correction coding, interleaving,
and quadrature amplitude modulation mapping have been maintained to keep
costs down and ease backward compatibility.
There are three key areas that need to be considered when addressing
increases in WLAN performance. First, improvements in radio technology are
needed to increase the physical transfer rate. Second, new mechanisms imple-
menting the effective management of enhanced physical layer performance modes
must be developed. Third, improvements in data transfer efﬁ ciency are needed to
reduce the improvements achieved with an increase in physical transfer rate.
The emerging 802.11n speciﬁ cation differs from its predecessors in that it
provides for a variety of optional modes and conﬁ gurations that dictate different
maximum raw data rates. This enables the standard to provide baseline performance
parameters for all 802.11n devices, while allowing manufacturers to enhance or tune
capabilities to accommodate different applications and price points. WLAN hard-
ware does not need to support every option to be compliant with the standard.
The ﬁ rst requirement is to support an OFDM implementation that improves
upon the one employed in 802.11a/g standards, using a higher maximum code
rate and slightly wider bandwidth. This change improves the highest attainable
raw data rate to 65 Mbps from 54 Mbps in the existing standards.
|
| |
Strukturaviy zarar va muvaffaqiyatsizliklar

|
Strukturaviy zarar va muvaffaqiyatsizliklar
|
bet | 10/10 | Sana | 04.12.2023 | Hajmi | 32,84 Kb. | | #110872 |
Bog'liq zararkunanda dasturlar va ulardan himoyalanishStrukturaviy zarar va muvaffaqiyatsizliklar:
Iloji bo'lsa, miqdoriy baholash usullaridan foydalanib, xavfli hodisalarning sabablarini batafsil tahlil qilish kerak. Ushbu muammoni hal qilish uchun, masalan, FMEA usuli (potentsial nomuvofiqliklarning turlari va oqibatlarini tahlil qilish) apqp (Advanced Product Quality Planning) ishlab chiqarish uchun mahsulotni ishlab chiqish va etkazib berish jarayonini joriy etish bilan birgalikda foydalanish mumkin. Ushbu jarayonning asosiy bosqichlari:
* butun jarayonni rejalashtirish bosqichi, "iste'molchi ovozi" ni tahlil qilish va kelajakdagi mahsulot kontseptsiyasini yaratish;
* dizayn (mahsulotlar);
* ishlab chiqarish texnologiyasini loyihalash;
* ishlab chiqarishni tayyorlash;
* ishlab chiqarish, takomillashtirish, iste'molchi bilan aloqa.
Dizayn bosqichida dizayn (ishlab chiqarish) FMEA usuli bilan har qanday komponentlarning muvaffaqiyatsizligini, ushbu muvaffaqiyatsizlikning sabablarini va ularning tizimga ta'sirini aniqlashga imkon beradi.
Ishni rejalashtirish xatolar:
Rejaning barcha ishlarini tahlil qilish tavsiya etiladi. Agar asossiz qisqa muddatlarga ega bo'lgan ish rejasida aniqlangan bo'lsa, unda ijro etuvchi tomonidan bajarilgan ish vaqtini hisoblash asosida muddatlarni majburiy muvofiqlashtirish kerak.
http://fayllar.org
|
| |
Zararli dasturlarni olib tashlashning eng yaxshi vositasi

Zararli dasturlarni olib tashlashning eng yaxshi vositasi
Ushbu kontekstda zararli bo'lmagan zararli emas, balki foydalanuvchilarni bilmasdan o'rnatilgan va barchasini olib tashlagan kompyuterda istalmagan faoliyatni olib tashlash kerakligi juda qadrlidir ularni.
Biz derazalar va zararli dasturlar va fayllardan tozalaymiz
Ushbu videoda sizga Windows operatsion tizimidagi kompyuterni qanday qilib josuslik va zararli dasturlar va fayllardan tozalash kerak, shuningdek, imo-ishorilgan diskka vaqtincha fayllardan va keshni qanday tozalash kerakligini aytaman. Uchta bepul kommunal xizmatlarni sharhlash amalga oshiriladi.
Kompyuter virusi - zararli dasturlar, uning maqsadi, uning egasiga o'z bilimisiz shaxsiy kompyuter egasiga zarar etkazadigan harakatlarni o'tkazishdir. Viruslarning o'ziga xos xususiyati - bu ko'payishdir. Siz virusni Internet orqali yoki olinadigan media orqali olishingiz mumkin: miltillovchi disklar, disketa disklari, disklar. Viruslar odatda tananing tanasiga kiritiladi yoki dasturlarni almashtiradi.
Trojan dasturi (Shuningdek, Troan, Troy, shoky ot) kabi nomlarni, zararsiz hodisalar ostida (masalan, kodek, ekranlar, ekskursiyalar, haydovchi va boshqalar) kabi zararli dastur. Virusdan farqli o'laroq, troyans o'z tarqalishiga ega emas. Siz ularni elektron pochta orqali Internet saytidan olishingiz mumkin bo'lgan ommaviy axborot vositalarida olishingiz mumkin.
Tarmoq qurti - operatsion tizimlarga nisbatan zaiflik bilan kompyuter hajmiga kiradigan mustaqil zararli dastur.
Raki - Tizimda zararli harakat hujumchisi izlarini yashirish uchun mo'ljallangan dastur. Bu har doim ham yomon emas. Masalan, rootkitlar va'zgo'ylardan foydalanish litsenziyalangan disklarning himoya tizimidir. Shuningdek, foydalanuvchiga zarar etkazmaydigan rootkit misoli virtual drayverlarni taqlid qilish uchun dastur bo'lib xizmat qilishi mumkin: demon asboblari, alkogol 120%.
Xulosa
Keraksiz dasturni olib tashlaydigan dasturlardan foydalanish antiviruslarni o'rnatish zarurligini yo'q qilmaydi. Har bir dastur o'z vazifalarini bajaradi. Anti-antivirus yordamida tizimni deyarli doimo doimiy ravishda himoya qiladi va tizim fayllarini infektsiya qilishiga to'sqinlik qiladi.
XAVF-XATARLARNI BAHOLASH VA TAHLILI.
Reja:
1.Xavf xatarlarni baholash usullari
2.Xatarlarni tahlil qilish usullarining qisqacha tavsifi
3. Xatarlarni tahlil qilishning analitik usuli
|
Trojan dasturlari - 1 mustaqil ish mavzu: Zararkunanda dasturlarning turlari Bajardi

Ushbu bo'limga turli xil ruxsatsiz harakatlarni amalga oshiradigan dasturlar mavjud: ma'lumot to'plash va uni tajovuzkor yoki zararli o'zgartirish, kompyuter resurslarini buzish, kompyuter resurslaridan noqonuniy maqsadlarda foydalanish.
Troyan dasturlarining alohida toifalari infektsiyalangan kompyuterning samaradorligini buzmasdan uzoq kompyuterlar va tarmoqlarga zarar etkazadi (masalan, uzoq tarmoqqa masofadan tarmoq resurslariga katta dosga hujum qilish uchun troyan dasturlari).
viruslar, qurtlar va troyan dasturlarini (dizaynerlar) avtomatlashtirish;
dastur kutubxonalari zararli dasturlarni yaratishga mo'ljallangan;
xakerlik yordamchi dasturlari Antivirusni tekshirishdan infektsiyalangan fayllar kodini (fayl shifrlash vositalari) yashiradi;
"Yomon hazil", kompyuter bilan ishlashga xalaqit beradi;
foydalanuvchiga ularning tizimdagi harakatlari to'g'risida bila turib yolg'on ma'lumot berilgan dasturlar;
boshqa usullar, bir yoki boshqa usulda, bu yoki uzoq masofaviy kompyuterlarga to'g'ridan-to'g'ri yoki bilvosita shikastlanishni qasddan qo'llash.
Va zarur bo'lgan muammolarni bartaraf etish uchun, asosan antivirus samarasiz bo'lib chiqadi. Bir vaqtning o'zida ikkita variantdan foydalanish - o'rnatilgan va vaqti-vaqti bilan ishga tushirilgan kommunal xizmatlardan maksimal darajada himoya qilish samaradorligini ta'minlash. Kompyuterda ko'proq xavfsizlikka ega bo'lish uchun, u ma'qul, u maqbuldir:
shubhali resurslarga kirish joyida ogohlantirishlar berishga antivirus yordamini berish bo'yicha tavsiyalarni amalga oshirish;
ko'rsatilgan antivirusni tekshirish yoki uning kelib chiqishi noma'lum bo'lgan tashqi media fayllaridan yozib olingan (masalan, rasmiy saytdan emas, balki tashqi saytdan yuklab olinmagan);
antivirusni sozlashda dasturni qo'lda ishlatish uchun viruslar ma'lumotlar bazalarini avtomatik yangilash va qo'lda foydalanish uchun kamida bir marta.
Kompyuter infektsiyasining viruslari va boshqa turdagi zararli kodning boshqa turlari muammolarni kamaytiradi. Garchi 100% himihat kıvkık bermasa ham, hatto pullik antivirus ham.
|
Mahalliy dasturlar kompyuteringizga qanday tushadi?

|
Mahalliy dasturlar kompyuteringizga qanday tushadi?
|
bet | 4/10 | Sana | 04.12.2023 | Hajmi | 32,84 Kb. | | #110872 |
Bog'liq zararkunanda dasturlar va ulardan himoyalanishMahalliy dasturlar kompyuteringizga qanday tushadi?
Zararli dasturlar kompyuterga turli xil mexanizmlar orqali kirishi mumkin, ularning aksariyati inson va texnik omil kombinatsiyasidan foydalanadi.
Masalan, zararli dasturni yaratuvchisi sizni xatni kiritish yoki xatga ulash orqali zararli dasturni yuklab olishingizga yordam berishi mumkin. Bundan tashqari, zararli dasturni standart dasturning noqonuniy nusxasi bilan to'ldirish mumkin, shuning uchun asl versiyalarni to'lash o'rniga ushbu noqonuniy nusxalarni tanlagan foydalanuvchilarga.
Zararli dastur - kompyuter dasturi yoki kompyuter tizimida yashirilgan ma'lumotlarning tahdidlarini amalga oshirish uchun mo'ljallangan yoki tizim resurslaridan yashirilgan yoki kompyuter tizimining normal ishlashiga xalaqit beradigan boshqa ta'sirni amalga oshirish uchun kompyuter dasturi yoki noutbuk kodi.
Ba'zi bir qurtlar (yallig'lanish) yoki "partiya" yoki "partiya" qurtlari) tarmoq paketlari shaklida tarqatiladi, to'g'ridan-to'g'ri kompyuter xotirasiga kirib, ularning kodini faollashtiradi.
Uzoq kompyuterlarga kirib borish va Worms nusxasini ochish uchun turli xil usullar qo'llaniladi: ijtimoiy muhandislik (masalan, qayd yozuvini ochishga chaqiradigan elektron pochta matni), tarmoq konfiguratsiyasida kamchiliklar (masalan, diskka nusxalash, To'liq kirish uchun ochiq) Xavfsizlik xizmatlari operatsion tizimlari va dasturlardagi xatolar.
Ba'zi qurtlar, shuningdek, boshqa zararli dasturlarning xususiyatlariga ega. Masalan, ba'zi qurtlar troyanslarda yoki mahalliy diskdagi bajariladigan fayllarni yuqtirishga qodir, ya'ni troyan dasturi va / yoki kompyuter virusi xususiyatiga ega.
Klassik kompyuter viruslari
har qanday foydalanuvchi harakatlari uchun kodingizni keyingi ishga tushirish;
boshqa kompyuter resurslariga qo'shimcha ravishda amalga oshirish.
Vazirlar, viruslar boshqa kompyuterlarga kirish uchun tarmoq xizmatlaridan foydalanmaydi. Virusning virusining nusxasi faqat uzoq kompyuterlarga tushadi, faqat virusga bog'liq sabablarga ko'ra infektsiyalangan ob'ekt boshqa kompyuterda faollashtiriladi, masalan:
mavjud disklar bilan kasallanganda virus tarmoq manbai ustida joylashgan fayllarni kiritdi;
virusni olib tashlanadigan vosita yoki unga yuqtirilgan fayllarni yuqtirgan;
foydalanuvchi infektsiyalangan biriktirma bilan elektron pochta xabarini yubordi.
M24
Ba'zi viruslarda zararli dasturlarning xususiyatlari, masalan, diskdagi ma'lumotlarni yo'q qilishning orqa tomoni yoki troyan komponenti mavjud.
|
| |
IP adreslarni qanday turlari bor va ularning farqi nimada?

|
IP adreslarni qanday turlari bor va ularning farqi nimada?
|
bet | 15/22 | Sana | 12.01.2024 | Hajmi | 67,52 Kb. | | #135470 |
Bog'liq 1. Kompyuter tarmoqlarining hududiy taqsimlanishi-fayllar.org28. IP adreslarni qanday turlari bor va ularning farqi nimada?
Siz ilgari IP-manzillarni eshitgan bo'lsangiz ham, siz IP-manzillarning muayyan turlarini aniqlay olmaysiz. Barcha IP-manzillar raqamlar yoki harflardan iborat bo'lsa-da, barcha manzillar bir xil maqsadlarda ishlatilmaydi.
Xususiy IP-manzillar , umumiy IP-manzillar , statik IP-manzillar va dinamik IP-manzillar mavjud . Bu juda ko'p! Ushbu ishoratlardan so'ng ularning har biri nimani nazarda tutganligi haqida ko'proq ma'lumot beradi. Murakkablikni kiritish uchun IP-manzilning har bir turi IPv4-manzil yoki IPv6 manzil bo'lishi mumkin.
29. MAC-adres nima?
MAC-manzil ( inglizcha Media Access Control-dan - atrof-muhitga kirishni nazorat qilish , shuningdek, apparat manzili , shuningdek jismoniy manzil ) - bu har bir faol uskunaning birligi yoki ularning chekilgan kompyuter chekilgan tarmoqlaridagi ba'zi interfeyslari uchun berilgan noyob identifikator .
Ethernet standartini loyihalashda har bir tarmoq kartasida (shuningdek, o'rnatilgan tarmoq interfeysida) ishlab chiqarish jarayonida unga "tikilgan" noyob olti baytli raqam (MAC-manzil) bo'lishi kerakligi nazarda tutilgan edi . Ushbu raqam freymni yuboruvchi va qabul qiluvchini aniqlash uchun ishlatiladi ; va tarmoqda yangi kompyuter (yoki boshqa tarmoqqa mos keladigan qurilma) paydo bo'lganda, tarmoq ma'muri ushbu kompyuter uchun MAC manzilini qo'lda sozlashi shart emas deb taxmin qilinadi.
Har bir tarmoq bilan ishlovchi modulning o'z fizik adresi bo'ladi, misol uchun Wi-Fi modulda, kompyuterdagi tarmoq kartasida. Bu modullar zavodda ishlab chiqarilish mobaynida o'z unikal fizik adresiga ega bo'ladi, demak bu fizik adres o'zgarmas va har bir modul uchun alohida bo'ladi, shu adresga MAC adres deyiladi. MAC adresni nazariy jihatdan o'zgartirib bo'lmaydi, lekin ba'zi dasturlar buni o'zgartirishga ham erishishmoqda.
30. IEEE 802.x standartlarining strukturasini tushuntirib bering.
IEEE ( Institute of Electrical and Electronics Engineers – elektrotexnika va radio-elektronika injenerlari instituti), IEEE 802.x standartlarining tuzilishi, kanal sathi, kanal sathining ikkita sath osti sathlariga bo’linishi, LLC va MAC sath osti sathlari, kanal sathi sath osti sathlarining asosiy vazifalari, 802 komitetning tarkibidagi bo’limlar.
|
| |