Unit 2 | SPM Notes | AKTU Notes

Project Life Cycle and Effort Estimation

Project Life Cycle: It represents different stages a software project goes through, from planning to delivery. The common stages are:

1. Requirement Analysis – Understanding what the software should do.

2. Design – Creating a blueprint of how the software will work.

3. Development (Coding) – Writing the actual code.

4. Testing – Checking for errors and fixing them.

5. Deployment – Releasing the software for use.

6. Maintenance – Updating and fixing issues after release.

Effort Estimation: Predicting how much time, cost, and work is required to complete a project. It helps in budgeting, resource allocation, and scheduling.

Software Process and Process Models

A software process is a set of steps followed to develop software efficiently. Different process models define how these steps are carried out.

Some common process models include:

• Waterfall Model – A step-by-step, linear approach (once a step is completed, it cannot be changed).
  
  
• Iterative Model – Develops software in repeated cycles, improving with each version.
  
  
• Spiral Model – Focuses on risk management by developing in phases.
  
  
• V-Model – Similar to Waterfall but includes testing at each stage.

Choice of Process Models

Choosing the right process model depends on:

• Project Size – Large projects may need Spiral or Iterative models.
  
  
• Project Complexity – Complex projects may use Agile methods.
  
  
• Customer Requirements – If requirements change frequently, Agile is better.
  
  
• Development Time – Rapid Application Development (RAD) is used when software needs to be delivered quickly.

Rapid Application Development (RAD)

RAD is a fast and flexible way to develop software. It focuses on:

• Quick Prototyping – Creating early versions for feedback.
  
  
• Minimal Planning – Less focus on documentation.
  
  
• Customer Involvement – Clients give feedback at every stage.

Example: Developing a mobile app where users test early versions and suggest improvements.

Agile Methods

Agile is a modern approach to software development. It focuses on:

• Short development cycles (sprints) – Software is developed in small parts.
  
  
• Customer feedback at every stage – Continuous improvements.
  
  
• Team collaboration – Developers, testers, and customers work together.

Example: Companies like Google and Amazon use Agile for continuous updates in their software.

Dynamic System Development Method (DSDM)

DSDM is an Agile-based framework that:

• Focuses on user involvement.
  
  
• Ensures projects are delivered on time.
  
  
• Allows changes even in later stages.

Example: Banking software development, where user feedback is essential.

Extreme Programming (XP)

XP is an Agile method that focuses on:

• Frequent releases – Small updates are made regularly.
  
  
• Pair programming – Two developers work together to improve quality.
  
  
• Continuous testing – Bugs are fixed as soon as they are found.

Example: Used in game development to fix issues quickly.

Managing Interactive Processes

Interactive processes involve:

• Continuous communication with users.
  
  
• Frequent updates and feedback collection.
  
  
• Adapting to changes during development.

This approach is commonly used in:

• E-commerce websites (like Amazon, Flipkart).
  
  
• Mobile applications (like Instagram, WhatsApp).

Basics of Software Estimation

Software estimation helps in predicting resources, time, and cost required for development. It involves:

• Effort Estimation – How much work is needed?
  
  
• Cost Estimation – How much money is required?
  
  
• Time Estimation – How long will it take?

Example: If an app development takes 5 developers working for 2 months, effort estimation helps calculate total work hours.

Effort and Cost Estimation Techniques

Different methods are used to estimate effort and cost:

1. Expert Judgment – Based on previous experience.

2. Analogy-Based Estimation – Comparing with similar past projects.

3. Parametric Estimation – Using formulas and models to predict cost.

4. COCOMO Model – A widely used cost estimation method.

COSMIC Full Function Points

COSMIC (Common Software Measurement International Consortium) is a method used to measure software size and complexity.

• It calculates function points based on the number of inputs, outputs, and data movements in a system.
  
  
• It helps in effort estimation and productivity analysis.

Example: Measuring the size of an inventory management system before development.

COCOMO II (Constructive Cost Model II)

COCOMO II is a mathematical model used to estimate:

• Effort (person-months) required for a project.
  
  
• Cost (budget) needed.
  
  
• Time (schedule) for completion.

It classifies software projects into:

• Organic – Small, simple projects (e.g., a college website).
  
  
• Semi-Detached – Medium projects (e.g., an office management system).
  
  
• Embedded – Large, complex projects (e.g., an airline reservation system).

Formula:

Effort = a * (Size)^b

A Parametric Productivity Model

• A parametric model uses mathematical formulas to estimate software cost, effort, and time.
  
  
• It considers various factors like team size, complexity, and productivity.
  
  
• Example models: COCOMO II, Function Point Analysis (FPA).

Example: If a banking application takes 100 function points, the model predicts effort and cost based on past data.