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PROCESS MODELS
◼
EVOLUTIONARY PROCESS
FLOW
The Prototype Model
◼ In prototype model we take user requirements.
Prototypes are build. User feedback is available.
◼ However this model is not suitable for large heavy requirements or complex embedded system.
When to use Prototype model:
◼ Prototype model should be used when the desired system needs to have a lot of interaction with the end users.
◼ Typically, online systems, web interfaces have a very high amount of interaction with end users, are best suited for Prototype model. It might take a while for a system to be built that allows ease of use and needs minimal training.
◼ Prototyping ensures that the end users constantly work with the system and provide a feedback
which is incorporated in the prototype to result in a useable system.
They are excellent for designing good human computer interface systems.
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Examples of prototyping projects
◼ Prototype model is like making E-COMMERCE websites.
◼ Other applications for which prototyping is
applicable are certain classes of mathematical algorithms, subset of command driven systems and other applications where results can be
easily examined without real-time interaction.
ADVANTAGES / DISADVANTAGES
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ADVANTAGES DISADVANTAGES
Users are actively involved in the development Leads to implementing and then repairing way of building systems.
Since in this methodology a working model of the system is provided, the users get a better understanding of the system being developed.
Practically, this methodology may increase the complexity of the system as scope of the system may expand beyond original plans.
Errors can be detected much earlier. Incomplete application may cause application not to be used
as the
full system was designed
Incomplete or inadequate problem analysis.
Quicker user feedback is available leading to better solutions.
Missing functionality can be identified easily
Confusing or difficult functions can be identified Requirements validation, Quick implementation of, incomplete, but functional, application.
The Spiral Model
◼ Spiral model combines architecture and
prototyping by stages. . It is considered to be evolutionary model, as after completing a cycle the product is again reviewed for further
changes in the same cycle.
◼ Though, it can also be considered a
combination of the Iterative and Waterfall
SDLC models with the significant accent on the risk analysis.
◼ Use cases for the Spiral model:
◼ Customer isn’t sure about the requirements
◼ Major edits are expected during the development cycle
◼ The projects with mid or high-level risk, where it is important to prevent these risks
◼ The new product that should be released in a few stages to have enough of
clients feedback
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Examples of prototyping projects
◼ To provide some example we can consider :-
◼ Gantt chart software – GanttPRO a tool for simple task handling.
◼ Evolution of Microsoft Windows operating system.
ADVANTAGES / DISADVANTAGES
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ADVANTAGES DISADVANTAGES
Lifecycle is divided into small parts, and if the risk
concentration is higher, the phase can be finished earlier to address the treats
Can be quite expensive
The development process is precisely documented yet scalable to the changes
The risk control demands involvement of the highly-skilled professionals
The scalability allows to make changes and add new functionality even at the relatively late stages
Can be ineffective for the small projects
The earlier working prototype is done - sooner users can point out the flaws
Big number of the intermediate stages requires excessive documentation