30-05-2012, 01:42 PM
Software Design
Software Design.ppt (Size: 1,020.5 KB / Downloads: 365)
Stages of Design
Problem understanding
Look at the problem from different angles to discover the design requirements.
Identify one or more solutions
Evaluate possible solutions and choose the most appropriate depending on the designer's experience and available resources.
Describe solution abstractions
Use graphical, formal or other descriptive notations to describe the components of the design.
Repeat process for each identified abstraction until the design is expressed in primitive terms.
Any design may be modelled as a directed graph made up of entities with attributes which participate in relationships.
The system should be described at several different levels of abstraction.
Design takes place in overlapping stages. It is artificial to separate it into distinct phases but some separation is usually necessary.
Top-down Design
In principle, top-down design involves starting at the uppermost components in the hierarchy and working down the hierarchy level by level.
In practice, large systems design is never truly top-down. Some branches are designed before others. Designers reuse experience (and sometimes components) during the design process.
Design Strategies
Functional design
The system is designed from a functional viewpoint. The system state is centralized and shared between the functions operating on that state.
Object-oriented design
The system is viewed as a collection of interacting objects. The system state is decentralized and each object manages its own state. Objects may be instances of an object class and communicate by exchanging methods.
Software Design.ppt (Size: 1,020.5 KB / Downloads: 365)
Stages of Design
Problem understanding
Look at the problem from different angles to discover the design requirements.
Identify one or more solutions
Evaluate possible solutions and choose the most appropriate depending on the designer's experience and available resources.
Describe solution abstractions
Use graphical, formal or other descriptive notations to describe the components of the design.
Repeat process for each identified abstraction until the design is expressed in primitive terms.
Any design may be modelled as a directed graph made up of entities with attributes which participate in relationships.
The system should be described at several different levels of abstraction.
Design takes place in overlapping stages. It is artificial to separate it into distinct phases but some separation is usually necessary.
Top-down Design
In principle, top-down design involves starting at the uppermost components in the hierarchy and working down the hierarchy level by level.
In practice, large systems design is never truly top-down. Some branches are designed before others. Designers reuse experience (and sometimes components) during the design process.
Design Strategies
Functional design
The system is designed from a functional viewpoint. The system state is centralized and shared between the functions operating on that state.
Object-oriented design
The system is viewed as a collection of interacting objects. The system state is decentralized and each object manages its own state. Objects may be instances of an object class and communicate by exchanging methods.