Qeiteri Armelle

[color=blue]System development model are also known as the process model. There are a lot of process models. Each of these process models have their phases and flow. Each phase performs very important functions, since the process models were used as a guide in developing a project.[/color]
[b][color=green]Waterfall Model[/color][/b]

[img]http://gedesanjaya.files.wordpress.com/2009/03/waterfall-models1.jpg[/img]

[color=blue]Waterfall model, it is one of the common models used in most of the projects. it has five phases, as what you've seen in the figure above, these phases are the requirements, design, implementation, verification and maintenance. When you first seen this model, you can actually comprehend of what is its flow. You cannot go to the next phase unless you have performed and finish to the first phase.

-requirement phase, in phase you should be able to identify the scope, and the functional and non-functional requirements of the project you were to develop. And again, you cannot proceed to design phase until you are done with these phase.

-design phase, in this phase you will be able to generate the design of the project it includes the database design, interface design, and even the flow and behavior of the project. In this phase the developer shall be able to develop the said project.

-next, implementation phase, in this phase, the developer will be able to implement and install the developed project.

-other phase, is the verification, with this the developer must able to verify or test the system he developed. it was important since all the program must be test after the installation and implementation. Last phase is the maintenance, in this phase the developer shall be able to maintain the developed project, it was crucial since end user might encounter error or failure that the developer didn’t face in the testing and verification phase. [/color]

[b][color=green]V- Model[/color][/b]

[img]http://www.qsius.com/images/f/f8/V-Model-Development.JPG[/img]

[color=blue]V model, it is a kind of process model which can be presumed as an extension for process model that I’ve elaborated above. This was called V model because its typically V in form. it has seven phases, which are the requirements, general design specification, detailed design specification, source code, unit testing, component testing and acceptance testing. it has many phases compare to the waterfall model but actually the two models has a similar function or phases.

The v model was actually has two major phases, these are the verification and validation phases, each of these major phases has sub phases.[/color]

[color=red]Verification phase[/color]

[color=blue]Under the verification phases we have the requirements, in this sub phase the developer shall be able to identify the functional and non-functional requirements of the project it also includes the problem identification, and identification of the scope and features. Next phase was general design specification, the developers will be able to analyze and understand the flow and behavior of the proposed or to-be developed system. In this phase the entity diagrams and data dictionary can be produced. And even the organization structures, system and menu structures will be generated in this phase. The detailed design phase is still under the verification phase, in the last sub phase the architectures like computer and software architectures are being produced. The database tables, interface relationship are also generated in this phase, the component testing design is also carried out in this phase.


Source code- it is only the phase in which it doesn’t belong to either validation or verification. The developer in this phase begins to do the prototyping and then followed by creating or coding the program. [/color]


[color=red]Validation Phase[/color]

[color=blue]Unit testing implies the first stage of dynamic testing process. According to software development expert Barry Boehm, “a fault discovered and corrected in the unit testing phase is more than a hundred times cheaper than if it is done after delivery to the customer.”
With this phase, it enables the developer to verify if the codes generated during the coding phase are efficient. Next is component testing, in this phase it also has sub phases which are the integration and system testing, in the integartion, it will going to validate the intercation of the integartation components and the system testing will compare the system specification against the actual system.
Lastly, the acceptance or the User acceptance testing, it was used to determine whether the system satisfies the requirements specified in the requirements phase.

[/color]

[color=green] Iterative and Incremental Developemnt[/color]

[img]http://stwinc.org/images/e/e3/Pdca_lair1.png[/img]

[color=blue]the figure above is just an example of an iterative and incremental development model of a project.
plan phase- the developer must plan the project to develope, it also includes the definition of the problem, identify teh scope and features. next is do or analyze and design the project, this phase is focus on the analization of the project and design its components adn also development of the project i sunder inthis phase. other is the check or simply test the project developed. last is act or evaluate or maintain the system you developed.[/color]



references:
http://en.wikipedia.org/wiki/Waterfall_model
http://en.wikipedia.org/wiki/V-Model_(software_development)
http://en.wikipedia.org/wiki/Iterative_and_incremental_development

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