Merging the specs

Huanwen Qu, Jeroen Zuijderwijk, Roy van den Broek

Today's assignment

Merge the result of team B and D's previous assignment Does it fit?

No? Make it fit What does the result give us?

Merging B and D

Team B specified the front- and back-end parts characteristics:

used messages to communicate between components

Team D specified the R&S-AS characteristics:

Use a graph to represent all the roads and sequences of nodes to represent the routes

System Architecture

R&S AS

Send 2

M4

GPS UNIT LED Display

Receive 2

M3M1

Send 1

M2

Receive 1

Putting everything togetherComparing M2 with the R&S-AS inputR&S-AS expects: GPS coordinates GPS time Bus IDMessage M2 (sent to the R&S-AS)

consists of the exact same elements

Putting everything togetherComparing the R&S-AS output with M3The R&S-AS outputs:

sequence of (route index, line number, ETA) route index is probably wrong and should

be stand ID

Team B expected the output (M3) to be: phone number of the bus stand ETA line number

Putting everything togetherModifying message M3

Let the R&S-AS output match message M3:

M3 becomes a sequence of (bus stand ID, line number, ETA)

Putting everything togetherModifying the ‘server phone’Change Send 2 from:

“a simple communication unit which forwards a message with stand address from the R&S-AS to that stand and removes the address from the message”

Putting everything togetherModifying the ‘server phone’ (2)Into a:

“a dispatcher unit which receives a sequence of (bus stand ID, line number, ETA) and does the exact same transmission as the original Send 2 for each item in the sequence”

Putting everything togetherSpecial cases (1)

There were special cases specified in team B’s solution. There is a different output Input is the same

How does the R&SAS know about traffic jams, strikes or accidents? An operator is contacted after receiving a certain number of messages M2 where the location is the same or almost the same

Putting everything togetherSpecial cases (2)

This would make the R&SAS have to keep track of previous messages The expensive operator should be left

out, because they can not give exact time information

ETA in M3 should be set to NEVER This would make message M3

match the format of original M3

Putting everything togetherSpecial cases (3)

If Receiver 2 receives a message M4 with ETA = NEVER Bus line and ETA are blanked from

the screen Will popup when the bus starts

moving again

Resulting system After merging we would have a system

that always shows the ETA of moving buses does not display information about buses

that are not moving fast enough Problem:

Two buses with the same line number will be displayed only one time on a display

Solution: Add bus id to messages M3 and M4