# UNIT 2: Software Project Management: Objectives, Resource Estimation, LOC & FP Estimation, Effort Estimation, COCOMO Model, Risk Analysis, Software Project Scheduling ## 2.1 Software Project Management (SPM) Fundamentals SPM encompasses planning, monitoring, and controlling software projects to ensure software is delivered on time, within budget, and meeting quality standards. ### The Management Spectrum (4 Ps) 1. **People**: Project managers, software engineers, clients, end-users. Human resource selection and team structure. 2. **Product**: Defining software scope, functional objectives, and technical constraints. 3. **Process**: Selecting the appropriate SDLC framework model. 4. **Project**: Planning, tracking, risk management, and quality control. --- ## 2.2 Software Size & Resource Estimation ### 1. Lines of Code (LOC) Direct, direct-count size metric measuring source code volume (e.g., SLOC, KLOC). - *Formula*: Productivity = $KLOC / \\text{Person-Months}$ - *Limitations*: Highly dependent on programming language syntax (1 LOC in Python != 1 LOC in Assembly); rewards verbose code; difficult to estimate early during requirement phase. --- ### 2. Albrecht Function Point (FP) Analysis Function Point analysis measures software size based on functional units delivered to the user, completely independent of programming language syntax. #### The 5 Information Domain Characteristics 1. **External Inputs (EI)**: Elementary user inputs that update internal system logical files (e.g., registration form submission). 2. **External Outputs (EO)**: Data processing outputs generated for users (e.g., report generation, confirmation receipt). 3. **External Inquiries (EQ)**: Interactive input queries resulting in immediate data retrieval without updating data files. 4. **Internal Logical Files (ILF)**: User-identifiable logical data groups maintained inside system boundary (e.g., database tables). 5. **External Interface Files (EIF)**: Data files maintained by external systems referenced for reading/lookup only. #### Step-by-Step Function Point Calculation 1. Calculate **Unadjusted Function Points (UFP)**: $$UFP = \\sum (\\text{Count}_i \\times \\text{Weight}_i)$$ where weight depends on complexity (Low, Average, High) of each of the 5 domain characteristics. 2. Determine **Value Adjustment Factor (VAF)** based on 14 General System Characteristics (GSCs) scored from 0 (no influence) to 5 (strong influence): - Data communications, Distributed processing, Performance, Heavily used configuration, Transaction rate, On-line data entry, End-user efficiency, On-line update, Complex processing, Reusability, Installation ease, Operational ease, Multiple sites, Facilitate change. 3. Calculate Total Degree of Influence ($EDI = \\sum F_i$, range 0 to 70). 4. Calculate final adjusted **Function Points (FP)**: $$FP = UFP \\times [ 0.65 + 0.01 \\times \\sum F_i ]$$ *(Note: The Adjustment Factor ranges from 0.65 when $EDI=0$ to 1.35 when $EDI=70$)*. --- ## 2.3 COCOMO Estimation Model (Boehm) Constructive Cost Model (COCOMO) is an empirical cost estimation model based on historical project data. ### Software Project Modes - **Organic Mode**: Small teams, familiar software environment, flexible requirements, minimal innovation needed. - **Semi-Detached Mode**: Medium teams, mixed experience levels, combination of rigid and flexible requirements. - **Embedded Mode**: Tight hardware/software/operational constraints, complex interfaces, high technical regulation. --- ### 1. Basic COCOMO Calculates effort and duration strictly as a function of estimated size in Thousands of Delivered Source Instructions (KLOC). #### Effort & Duration Formulas - Effort: $E = a \\cdot (KLOC)^b$ [Person-Months] - Development Duration: $D = c \\cdot (E)^d$ [Months] - Recommended Staff Size: $SS = E / D$ [Persons] #### Coefficient Constants Matrix | Mode | $a$ | $b$ | $c$ | $d$ | | :--- | :--- | :--- | :--- | :--- | | **Organic** | 2.4 | 1.05 | 2.5 | 0.38 | | **Semi-Detached** | 3.0 | 1.12 | 2.5 | 0.35 | | **Embedded** | 3.6 | 1.20 | 2.5 | 0.32 | --- ### 2. Intermediate COCOMO Extends Basic COCOMO by multiplying basic effort with an **Effort Adjustment Factor (EAF)** derived from 15 Cost Drivers across 4 categories: 1. *Product Attributes*: Required software reliability, Database size, Product complexity. 2. *Hardware Attributes*: Execution time constraint, Main memory constraint, Virtual machine volatility, Environment turn-around time. 3. *Personnel Attributes*: Analyst capability, Applications experience, Programmer capability, Virtual machine experience, Programming language experience. 4. *Project Attributes*: Use of modern software tools, Application of software engineering methods, Required development schedule. #### Formula $$E = a \\cdot (KLOC)^b \\times EAF$$ where $EAF = \\prod_{i=1}^{15} \\text{Cost Driver Rating}_i$. --- ### 3. Detailed (Complete) COCOMO Applies phase-sensitive cost driver ratings to individual subsystem modules, recognizing that cost factors vary across Requirements, High-Level Design, Detailed Design, Coding, Unit Testing, and Integration phases. --- ## 2.4 Risk Analysis & Management ### Risk Categories - **Project Risks**: Threaten project budget, schedule, staffing, and resources. - **Technical Risks**: Threaten quality and timeliness due to technical complexity or hardware limits. - **Business Risks**: Threaten economic viability (e.g., market risk, sales risk, management change risk). ### Risk Management Steps 1. **Risk Identification**: Brainstorming risk checklists (Product size, Business impact, Staff experience, Process maturity). 2. **Risk Projection (Estimation)**: Rate Risk Likelihood ($L_i$) and Risk Impact ($I_i$). Calculate Risk Exposure: $$RE = P(\\text{Risk}) \\times \\text{Cost of Risk}$$ 3. **Risk Refinement**: Breaking down macro risks into detailed micro risk components. 4. **Risk Mitigation, Monitoring, and Management (RMMM Plan)**: - *Mitigation*: Proactive steps to reduce risk likelihood or impact before it occurs. - *Monitoring*: Tracking risk indicators during development. - *Management*: Contingency plan execution if risk materializes. --- ## 2.5 Software Project Scheduling & Network Analysis ### Work Breakdown Structure (WBS) Decomposes total project scope into hierarchical, smaller work packages and tasks. ### 1. Gantt Chart Horizontal bar chart displaying task start dates, finish dates, durations, and task overlap dependencies. --- ### 2. PERT / CPM Network Analysis Program Evaluation and Review Technique (PERT) and Critical Path Method (CPM) represent project schedules as activity-on-edge or activity-on-node directed graphs. #### Key Terminology - **Earliest Start (ES)** / **Earliest Finish (EF)**: Earliest time a task can begin/end. - **Latest Start (LS)** / **Latest Finish (LF)**: Latest time a task can begin/end without delaying total project completion. - **Float / Slack Time**: Total time an activity can be delayed without delaying project completion date. $$\\text{Slack} = LS - ES = LF - EF$$ - **Critical Path**: Longest continuous path through activity network diagram. All activities on critical path have **Zero Float (Slack = 0)**. #### PERT Weighted Average Duration Calculation Since activity durations are uncertain, PERT uses 3-point estimates following a Beta distribution: 1. Optimistic Time ($a$): Shortest completion time under ideal conditions. 2. Most Likely Time ($m$): Normal completion time. 3. Pessimistic Time ($b$): Maximum completion time under worst conditions. #### Formulas - Expected Task Duration: $T_e = \\frac{a + 4m + b}{6}$ - Standard Deviation: $\\sigma = \\frac{b - a}{6}$ - Variance: $\\sigma^2 = \\left( \\frac{b - a}{6} \\right)^2$ --- ---