Posted by admin on Jan 15, 2020 in Computers | 0 comments
Chapter 4 Project UML
1.) UML – USE CASE
Elements
System: the software to be developed.
Represented as a rectangle with a name label at the top.
2) Actors: people or other external systems that interact with the system.
Represented as a stick figure with a name label.
Primary actors: who initiate actions appear to the left of the system
Secondary actors: who react to actions appear on the right of the system
All actors should be outside the system
3) Use cases: all possible operations the system can support
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Posted by admin on Nov 4, 2019 in Computers | 0 comments
Be recognized: A child is recognised as a person under the age of 18, unless national laws recognise an earlier age of majority. ARTICLE 2 Non-discrimination: All rights apply to all children without exception. It is the State’s obligation to protect children from any form of discrimination and to take positive action to promote their rights. ARTICLE 3 Adequate care : A child is recognised as a person under the age of 18, unless national laws recognise an earlier age of majority. ARTICLE 4 Implementation
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Posted by admin on Aug 5, 2019 in Computers | 0 comments
1. Television channels are 6 MHz wide. How many bits/sec can be sent if four-level digital signals are used?
“Max. data rate = 2B log 2 V bits/sec”, we can sample = 2 (6MHz) log 2 (4) = 24 million times/sec. four-level signals = 24 Mbps.
2. If a binary signal is sent over a 3-kHz channel whose signal-to-noise ratio is 20 dB, what is the maximum achievable data rate?
S/N = 10^2 = 100. So max data rate = (3000Hz)log2(1+100)bits/sec = 3000 * 6.643 = 19.92kbps
3. When the data-rate in T1 is 1.544
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Posted by admin on Jul 30, 2019 in Computers | 0 comments
1.) A group of N stations share a 56-kbps pure ALOHA channel. station outputs a 1000-bit, every 100 sec. maximum value of N?
usable bandwidth is 0.184 x 56 kbps = 10.3 kbps. N = 10300/10 = 1030 stations.
2.) Consider the delay of pure ALOHA versus slotted ALOHA at low load. Which one is less?
transmission can start instantly. At low load, no collisions are expected, the transmission will be successful.With slotted ALOHA, it has to wait for the next slot. This introduces half a slot
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Posted by admin on Jun 27, 2019 in Computers | 0 comments
ReproductionReproduction is an integral feature of all living beings. The process by which a living being produces its own like is called reproduction.
Importance of Reproduction:Reproduction is important for each species, because this is the only way for a living being to continue its lineage. Apart from being important for a particular individual, reproduction is also important for the whole ecosystem. Reproduction helps in maintaining a proper balance among various biotic constituents of the ecosystem.
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Posted by admin on May 27, 2019 in Computers | 0 comments
15. Consider the extended LAN connected using bridges B1 and B2 in the given Figure. a.)A sends a packet to C. (b) E sends a packet to F. (c) F sends a packet to E. (d) G sends a packet to E. (e) D sends a packet to A. (f) B sends a packet to F
a.) B1 will forward this packet on ports 2, 3, and 4. B2 will forward it on 1, 2 and 3. b.)B2 will forward this packet on ports 1, 3, and 4. B1 will forward it on 1, 2 and 3. c) B2 will not forward this packet on any of its ports, and B1 will
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