CS504- Software Engineering - I current MIDTERM EXAMINATION Spring 2011

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Question No: 17 ( Marks: 2 )
To manage the complexity of the system we need to apply the principles of separation of concern. Discuss briefly.
Separation of concern, modularity, and abstraction are different but related principles.
Separation of concern allows us to deal with different individual aspects of a problem by
considering these aspects in isolation and independent of each other.

WHAT is MODULES :
complex system may be divided into smaller pieces of lesser complexity called
modules.

Question No: 18 ( Marks: 2 )
What is elaborated Usecase? Explain it

Elaborated Use Cases
After the derivation of the use case model, each use is elaborated by adding detail of
interaction between the user and the software system. An elaborated use case has the
following components:
• Use Case Name
• Implementation Priority: the relative implementation priority of the use case.
• Actors: names of the actors that use this use case.
• Summary: a brief description of the use case.


Question No: 19 ( Marks: 2 )
What is Software Architecture?
Garlan and Perry, guest editorial to the IEEE Transactions on Software Engineering, April
1995:
Software architecture is "the structure of the components of a program/system,
their interrelationships, and principles and guidelines governing their design and
evolution over time."

Question No: 20 ( Marks: 3 )
What notation is used for Sequence Diagrams? Draw it graphically.

. The objects are organized in a horizontal line and the events in a vertical
time line.
The Notation
Following diagram illustrates the notation used for drawing sequence diagrams.
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Lifeline Message

Question No: 21 ( Marks: 3 )
How can we decrease Coupling explain it.

we can reduce the coupling of a system by minimizing the number of messages
in the protocol of a class. The problem with large public interfaces is that you can never
find what you are looking for…smaller public interfaces make a class easier to
understand and modify. This can be further elaborated with the help of the following
example. Suppose we have two functions defined for setting the desired temperature in
the room:


Question No: 22 ( Marks: 5 )
Narrate some of the architectural design guidelines that can help in addressing non-functional requirements challenges. ( PSSAM)

 Performance:
Performance can be enhanced by localising operations to minimise subsystem
communication. That is, try to have self-contained modules as
much as possible so that inter-module communication is minimized.

 Security
Security can be improved by using a layered architecture with critical
assets put in inner layers.

 Safety
Safety-critical components should be isolated

 Availability
– Availability can be ensured by building redundancy in the system and
having redundant components in the architecture.