UNIT – II SOFTWARE REQUIREMENTS CS2301 software Engineering

1. What is requirement engineering?

Requirement engineering is the process of establishing the services that the customer requires from the system and the constraints under which it operates   and is developed.

2. What are the various types of traceability in software engineering?

i. Source traceability – These are basically the links from requirement to stakeholders

ii. Requirements traceability – These are links between dependant requirements.

            iii. Design traceability – These are links from requirements to design.

3. Define software prototyping.

Software prototyping is defined as a rapid software development for   validating the requirements.

4. What are the benefits of prototyping?

i. Prototype serves as a basis for deriving system specification.  

ii. Design quality can be improved.                                                                                 

iii. System can be maintained easily.

iv. Development efforts may get reduced.

v. System usability can be improved.

5. What are the prototyping approaches in software process?

i. Evolutionary prototyping – the initial prototype is prepared and it is then refined through number of stages to final stage.

       ii. Throw-away prototyping – a rough practical implementation of the system is produced. The requirement problems can be identified from this implementation.

6. What are the advantages of evolutionary prototyping?

i. Fast delivery of the working system.     

ii. User is involved while developing the system.                                                  

iii. More useful system can be delivered.

iv. Specification, design and implementation work in co-ordinate manner.

7. What are the various Rapid prototyping techniques?

i. Dynamic high level language development.        

ii. Database programming. 

iii. Component and application assembly.

8. What is the use of User Interface prototyping?

This prototyping is used to pre-specify the look and feel of user interface  in an effective way.

                     

9. What are the characteristics of SRS?

 i. Correct – The SRS should be made up to date when appropriate requirements are identified.

 ii. Unambiguous – When the requirements are correctly understood then only it is possible to write an unambiguous software.

 iii. Complete – To make SRS complete, it should be specified what a software designer wants to create software.

 iv. Consistent – It should be consistent with reference to the functionalities identified.

             v. Specific – The requirements should be mentioned specifically.

 vi. Traceable – What is the need for mentioned requirement?

10. What is data modeling?

Data modeling is the basic step in the analysis modeling. In data modeling the data objects are examined independently of processing. The data model  represents how data are related with one another.

11. What is a data object?

Data object is a collection of attributes that act as an aspect, characteristic,   quality, or descriptor of the object.

12. What are attributes?

Attributes are the one, which defines the properties of data object.

13. What is cardinality in data modeling?

Cardinality in data modeling, cardinality specifies how the number of   occurrences of one object is related to the number of occurrences of another   object.

14. What does modality in data modeling indicates?

Modality indicates whether or not a particular data object must participate  in the relationship.

15. What is ERD?

Entity Relationship Diagram is the graphical representation of the object  relationship pair. It is mainly used in database applications.

16. What is DFD?

Data Flow Diagram depicts the information flow and the transforms that are applied on the data as it moves from input to output.

17. What does Level0 DFD represent?

Level 0 DFD is called as ‘fundamental system model’ or ‘context model’. In the context model the entire software system is represented by a single bubble with input and output indicated by incoming and outgoing arrows.

18. What is a state transition diagram?

State transition diagram is basically a collection of states and events. The events cause the system to change its state. It also represents what actions are to   be taken on the occurrence of particular event.

 19. Define Data Dictionary.

The data dictionary can be defined as an organized collection of all the data elements of the system with precise and rigorous definitions so that user and system analyst will have a common understanding of inputs, outputs, components of stores and intermediate calculations.

 20. What are the elements of Analysis model?

i. Data Dictionary

ii. Entity Relationship Diagram

iii. Data Flow Diagram

iv. State Transition Diagram

v. Control Specification

vi. Process specification.

21. What are functional requirements?

                        Functional requirements are” statements of services the system should provide how the system should react to particular input and how the system should behave in particular situation.

22. What are non functional requirements?

                        Non functional requirements are constraints on the services or functions offered by the system such as timing constraints, constraints on the development process, standards, etc……..

23. What is the outcome of feasibility study?

                        The outcome of feasibility study is the results obtained from the following questions:

·         Which system contributes to organizational objectives?

·          Whether the system can be engineered? Is it within the budget?

·         Whether the system can be integrated with other existing system?

24. What is meant by structural analysis?

                         The structural analysis is mapping of problem domain to flows and transformations. The system can be modeled by using Entity Relationship diagram, Data flow diagram and Control flow diagrams.