Structured systems analysis and design

Structured Systems Analysis and Design (SSAD)
With this particular methodology, a software development venture is divided into stages, steps, tasks and modules/ components.
Objectives of SSAD:  ITC Infotech India Ltd.
Structured Systems Analysis and Design (SSAD) was developed with specific objectives:

To warrant that a project could lucratively persist should a loss in staff occur without any adverse consequences on the project
To improve communication between all participants in the project so that an effective construction is in place
To develop a better of class systems
To improve the manner in which projects are controlled and directed
To allow for the efficient use of both experienced and inexperienced staff
To allow for projects to be supported by computer- aided software engineering applications

How SSAD works:
SSAD is a waterfall approach whereby there are a series of events which occur in sequential order, each step leading from the last. There are a total of five steps and they are as follows:

Feasibility study: This is a study that will determine if the project is actually possible to undertake and whether it is cost effective or not.
Requirements analysis: Identifying the needs of the business
Requirements specification: The requirements (functional and non- functional) are clearly and unambiguously identified and stated.
Logical system specification: The technical systems options are created and also the logical design of the system, including upgrade and enquiry designs.
Physical design: The logical system specification and technical specification is then used to design a physical database and set of program specifications.

Advantages of SSAD:

Timelines: as mentioned before, SSAD can be used to improve the way a project is controlled and directed. This is due to the fact that it allows one to plan the project well which is essential to deliver the product on time.
Improvement of productivity: By encouraging on-time delivery, meeting business needs, ensuring better quality, using human resources effectively as well as evading bureaucracy, SSAD improves general productivity of the project.
Better quality: Decreases the error rate of information systems by identifying a certain level of class in the launch and constantly checking the system.
Effective use of skills: It does not require any special skills and can easily be taught to the staff. It usually makes use of diagramming and modelling tools.
It can respond to changes in the business environment: Business requirements and objectives are taken into consideration while the project is being developed. This creates the possibility to adjust the planning of the project to the actual requirements of the business.
Usability: Special emphasis is put on the analysis of the user requirements. Concurrently, the system model is constructed and a wide-ranging demand analysis is conducted.
Cuts costs: Due to the fact that SSAD separates logical and physical systems design, the system does not have to be executed again with new hardware or software.

Disadvantages of SSAD:

SSAD puts prominence on the analysis of a system and its documentation. This paves the way for over-analysing, which in turn can be very time consuming and puts strain on expense.

Available from: http://www.scribd.com/doc/19681828/SSAD
[Date accessed: November 25th, 2009]
Object Oriented Analysis and Design:
    This is a software development approach that puts great prominence on logical solutions based on objects (individual components of a system). It takes a bottom- top developmental approach and makes use of UML (Unified Modelling Language).
Objectives of OOAD:  JS Consulting Group Inc. (2000-2009)

To study already existing objects to see if they can in fact be reused or adapted for newer uses.
To identify new or modified objects that will be pooled with existing objects into a useful business computing application.

Available from: http://www.jscgroup.com/object-oriented-analysis-and-design.html
[Date accessed: October 25th, 2009]
How OOAD works: Kenneth Pefkaros, International Journal of Business research, March 2008.
    In OOAD, the developers capture required details as a system of objects which encapsulate both data and processes. It uses three elemental techniques to for analysis:

Functional modelling: The analyst uses activity diagrams and use case diagrams to give designers a clearer picture of how the system works.
Structural modelling: The analyst uses class diagrams to group related objects.
Behavioural diagrams: The analyst uses sequence diagrams, communication and state diagrams, to give a basic description of how objects respond to the environment, as well as, how they change state during transactions.

These techniques then provide the designers with sufficient documented information which they will use in the creating of the system.
Available from: http://findarticles.com/p/articles/mi_6773/is_2_8/ai_n31126769/pg_4/?tag=content;col1
[Date accessed: October 25th, 2009]
Advantages of OOAD:

It significantly simplifies the development of the system
It enables the consistency of objects which increases the understanding of the design
Decomposing the system into individual objects makes it easier and more manageable for the analyst to work with.
When working with objects, they can be reused and modified which cuts costs and save time.

Disadvantages of OOAD:

There is more emphasis on codes
There isn’t much emphasis on team work
The early designs for the system may be too simplified to be adequate
It isn’t easy to establish all the necessary classes and objects needed for the system