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Milav Dabgar
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Milav Dabgar
Experienced lecturer in the electrical and electronic manufacturing industry. Skilled in Embedded Systems, Image Processing, Data Science, MATLAB, Python, STM32. Strong education professional with a Master’s degree in Communication Systems Engineering from L.D. College of Engineering - Ahmedabad.
Lecture 08: The Prototype Model

Lecture 08: The Prototype Model

Unit 2: Software Development Life Cycle (4353202)

Lecture Agenda

  • Recap of the Incremental Model
  • What is the Prototype Model?
  • The Prototyping Process: Steps and Iteration
  • Types of Prototyping
  • Advantages of the Prototype Model
  • Disadvantages of the Prototype Model
  • When to Use the Prototype Model
  • Summary and Q&A

Recap of the Incremental Model

The Incremental Model delivers software in small, usable increments, allowing for early user feedback and adaptation. It is more flexible than the Waterfall model and suitable for projects with evolving requirements.

What is the Prototype Model?

The Prototype Model is an SDLC model where a working model (a prototype) of the software is built early in the development process. This prototype is then refined through iterative feedback from stakeholders until it meets their needs, after which the final system is developed.

It is particularly useful when requirements are unclear or complex, as it provides a tangible representation for discussion and validation.

The Prototyping Process: Steps and Iteration

The prototyping process is iterative and involves continuous refinement based on user feedback.

graph TD A[1. Requirements Gathering] --> B{2. Quick Design} B --> C[3. Build Prototype] C --> D{4. Customer Evaluation} D -- Feedback & Refinement --> B D -- Accept Prototype --> E[5. Design & Implement Final System]
  1. Requirements Gathering: Initial, high-level requirements are collected.
  2. Quick Design: A preliminary design is created quickly, focusing on key functionalities.
  3. Build Prototype: A working model is developed based on the quick design. This is not the final system.
  4. Customer Evaluation: The prototype is presented to the customer for evaluation and feedback.
  5. Refinement & Iteration: Based on feedback, the prototype is refined, or new requirements are gathered, and the cycle repeats until the customer is satisfied.
  6. Design & Implement Final System: Once the prototype is accepted, the actual system is built based on the refined requirements and design.

Types of Prototyping

  • Rapid Throwaway Prototyping:
    • Purpose: To quickly explore requirements and design options.
    • Outcome: The prototype is discarded once requirements are clear. The final system is built from scratch.
    • Benefit: Avoids building the wrong system.
  • Evolutionary Prototyping:
    • Purpose: To build a robust prototype that gradually evolves into the final system.
    • Outcome: The prototype is continuously refined and extended.
    • Benefit: Reduces development time as the prototype becomes the product.
  • Incremental Prototyping:
    • Purpose: The system is broken into smaller prototypes, developed independently, and then integrated.
    • Outcome: A series of prototypes that eventually form the complete system.
    • Benefit: Combines benefits of incremental model with prototyping.

Advantages of the Prototype Model

  • Active User Involvement: Users are deeply involved, leading to a better understanding of their needs and higher satisfaction.
  • Better Requirement Understanding: A working model clarifies ambiguous requirements and uncovers hidden ones.
  • Early Error Detection: Defects and design flaws are identified and corrected early, reducing rework costs.
  • Reduced Risk: Technical and business risks are mitigated by validating concepts with the prototype.
  • Improved Communication: Provides a tangible basis for discussion between users and developers.
  • Flexibility: Accommodates changes more easily than linear models.

Disadvantages of the Prototype Model

  • Increased Complexity: The iterative nature can lead to uncontrolled scope expansion if not managed strictly.
  • Potential for Lower Quality (Throwaway): If the prototype is built quickly without quality in mind, it might not be suitable as a base for the final system.
  • User Confusion: Users might mistake the prototype for the final product and expect it to be fully functional and robust.
  • Higher Cost & Time (Potentially): Building and refining prototypes can add to the overall project cost and duration if not managed efficiently.
  • Lack of Documentation: Focus on rapid development might lead to insufficient documentation.

When to Use the Prototype Model

The Prototype model is best suited for projects where:

  • Requirements are **unclear, ambiguous, or expected to evolve**.
  • The user interface and user experience (UI/UX) are **critical** components.
  • There is a **high level of technical risk** or uncertainty about the feasibility of a solution.
  • Stakeholders need a **tangible model** to provide effective feedback.
  • The project involves **new technologies** or innovative features.

Summary and Q&A

Key Takeaways

  • The **Prototype Model** involves building an early working model to clarify requirements and gather feedback.
  • It is **iterative** and highly **user-centric**, ideal for projects with **unclear requirements**.
  • Types include **throwaway, evolutionary, and incremental** prototyping.
  • Offers **early error detection** and **reduced risk** but requires careful management to avoid scope creep and cost overruns.

Q & A

Questions & Discussion