UGC NET Computer Science December 2019 | Question 139

Question 139

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Weather Information System

The sequence diagram given in Figure 1 for the Weather Information System takes place when an external system requests the summarized data from the weather station. The increasing order of lifeline for the objects in the system are:

1. 1. Sat comms → Weather station → Commslink → Weather data
2. 2. Sat comms → Comms link → Weather station → Weather data
3. 3. Weather data → Comms link → Weather station → Sat Comms
4. 4. Weather data → Weather station → Comms link > Sat Comms
5. 5. Question remains cancelled

Answer : 5. Question remains cancelled

Explanation Question 139

According to given UGC NET final key, question remains cancelled and marks awarded to all Page 1 candidates appeared in the test.

A connection is established in order to send and receive data between sender and receiver. And a link is disconnect after completion of data transfer.

Given diagram, Sat Comms requests data to whether station, whether station requests data to Comms link and comm link requests data from whether data.

Comm link gets data first from whether data then the link between comm link and whether data is smallest. Similarly lifetime if connection between Sat comms and whether station is largest.

Hence the increasing order of lifeline for the objects in the system are Weather data → Comms link → Weather station → Sat Comms.

Note: Most appropriate answer is option-C.

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