Solution - Short Notes (Any Two)

a) Software Reuse

Using existing assets (code, design, docs, COTS) in new projects. Types: Application system reuse, Component reuse, Object/function reuse. Benefits: Quality, cost, time saved. Problems: Not invented here, component trust, maintenance. Approaches: COTS, Product lines, Libraries.

b) Spiral Model (Barry Boehm)

Risk-driven iterative model with 4 quadrants: Objective setting → Risk analysis → Development & Validation → Planning next loop. Each spiral = version. Best for large/high-risk projects; supports prototyping. Costly for small projects.

c) Six Sigma

Quality strategy aiming 3.4 defects per million opportunities. DMAIC: Define-Measure-Analyze-Improve-Control. Uses statistical tools (SPC). Levels: White/Yellow/Green/Black Belt. Focus on defect prevention, process variation reduction.

d) Verification and Validation

V&V: Ensure quality.

• Verification: Are we building product right? (Static: reviews, inspections) vs
• Validation: Are we building right product? (Dynamic: testing).
  Both throughout SDLC; V&V plan includes reviews, testing (unit → acceptance) and audits.