UNIT – III ANALYSIS, DESIGN CONCEPTS AND PRINCIPLES

1. What are the elements of design model?

i. Data design             

ii. Architectural design                                                                                                 

iii. Interface design                                                                                         

iv. Component-level design

2. Define design process.

Design process is a sequence of steps carried through which the requirements are translated into a system or software model.

3. List the principles of a software design.

i. The design process should not suffer from “tunnel vision”

ii. The design should be traceable to the analysis model.

iii. The design should exhibit uniformity and integration.

iv. Design is not coding.

v. The design should not reinvent the wheel.

4. What is the benefit of modular design?

Changes made during testing and maintenance becomes manageable and they do not affect other modules.

5. What is a cohesive module?

A cohesive module performs only “one task” in software procedure with little interaction with other modules. In other words cohesive module performs only one thing.

6. What are the different types of Cohesion?

i. Coincidentally cohesive - The modules in which the set I\of tasks are related with each other loosely.

 ii. Logically cohesive – A module that performs the tasks that are logically related with each other.

 iii. Temporal cohesion – The module in which the tasks need to be executed in some specific time span.

 iv. Procedural cohesion – When processing elements of a module are related with one another and must be executed in some specific order.

                        v. Communicational cohesion – When the processing elements of a module share the data then such module is called communicational cohesive.

7. What is coupling?

Coupling is the measure of interconnection among modules in a program structure. It depends on the interface complexity between modules. 

8. What are the various types of coupling?

i. Data coupling – The data coupling is possible by parameter passing or data interaction.

                        ii. Control coupling – The modules share related control data in control coupling.

iii. Common coupling – The common data or a global data is shared among modules.

                        iv. Content coupling – Content coupling occurs when one module makes use of data or control information maintained in another module.

9. What are the common activities in design process?

i. System structuring – The system is subdivided into principle subsystems components and communications between these subsystems are identified.

ii. Control modeling – A model of control relationships between different parts of the system is established.

iii. Modular decomposition – The identified subsystems are decomposed into modules.

 10. What are the benefits of horizontal partitioning?

i. Software that is easy to test.

ii. Software that is easier to maintain.

iii. Propagation of fewer side effects.

iv. Software that is easier to extend.

11. What is vertical partitioning?

Vertical partitioning often called factoring suggests that the control and work should be distributed top-down in program structure.

12. What are the advantages of vertical partitioning?

i. These are easy to maintain changes.

ii. They reduce the change impact and error propagation.

13. What are the various elements of data design?

i. Data object – The data objects are identified and relationship among various data objects can be represented using ERD or data dictionaries.

            ii. Databases – Using software design model, the data models are translated into data structures and data bases at the application level.

            iii. Data warehouses – At the business level useful information is identified from various databases and the data warehouses are created.