Overview of systems Analysis and design for Computer Science and MCA students

Write a short note on Object Oriented Methodology.

• Object Oriented Methodology is a popular design approach for analyzing and designing an application.
• It is an Object modeling language.
• It is a new system development approach, encouraging and facilitating re-use of software components.
• It employs international standard Unified Modeling Language (UML) from the Object Management Group (OMG).
• Using this methodology, a system can be developed on a component basis, which enables the effective re-use of existing components.

• To encourage greater re-use.
• To produce a more detailed specification of system constraints.
• To have fewer problems with validation (Are we building the right product?).

• It represents the problem domain, because it is easier to produce and understand designs.
• It allows changes to be done more easily.
• It provides a good structure for abstracting the modular design.
• It reduces the complexity of software object model.
• It increases the quality of software model.
• It becomes easy to reuse the code in a new system.
• As the objects are maintained separately, it helps in locating and fixing the problems easily.
• The object oriented applications are more scalable than structured approach.
• It is easier to make minor changes in the data representation of an object oriented program.
• It involves the transmission of messages back and forth over a network.

• This process is related to identifying business needs and opportunities.
• It defines a detail information about the system design and user requirements, but the requirements should be testable, measurable and documented.
• Requirement process may result in success or failure of a software product.
• This process can be too long.

• The main goal of the analysis is to build the models.
• The requirements of the users, developers and managers provide the information needed to develop the initial problem statement.

• It specifies all the details required to describe how the system will be implemented.
• The details of the system analysis and system design are implemented during this phase.
• The objects identified in the system design phase are designed.

• It uses the structure created during the design phase.
• It is the process that uses the lowest-level system elements in the software system.
• The main purpose of this process is to design and create a software system according to their requirements.

Write a short note on Spiral Model.

• Spiral model is a risk driven process model.
• It is used for generating the software projects.
• In spiral model, an alternate solution is provided if the risk is found in the risk analysis, then these alternate solutions are suggested and implemented.
• It is a combination of prototype and sequential model.
• In one iteration all activities are done, for large project's the output is small.

• The risk driven model identifies and prioritizes the risk, and in the spiral model, there is a possibility of various risks occurring while building the software product.
• The risk driven model selects and applies a set of architecture techniques and evaluates risk reduction.
• The main purpose of risk driven model is to help the developers to decide how much architecture work is to be done.

• When the requirements are complex at that time spiral model is used.
• This model is used for large projects.
• Significant changes are required for projects.
• When cost and risk evaluation is important then spiral model is used.

• Requirements are gathered during the planning phase.
• During this phase the requirements are understood and finalized.

• In risk analysis phase, a process is used to identify risk and alternate solutions.
• At the end of the phase a prototype is produced.
• If a risk is found then alternate solutions are suggested and implemented.

• In engineering phase, a software is developed and tested at the end of the phase.

• In the evaluation phase, a customer evaluates the output of the project before it goes to the next step of the spiral model.

• It reduces high amount of risk.
• It is good for large and critical projects.
• It gives strong approval and documentation control.
• In spiral model, the software is produced early in the life cycle process.

• Highly specified expertise is required for risk analysis.
• It can be costly to develop a software model.
• It is not used for small projects.

Compare Spiral Model and RAD Model.