network diagrams as tools to plan operations

9.3 Operations Strategy – Operations Planning and CPA 🚀

What is Operations Planning?

Operations planning is like creating a roadmap for a big school event. It tells us what needs to be done, when it should start, and how long it will take. The goal is to make sure everything runs smoothly and on time.

CPA – Capacity Planning & Allocation 📊

CPA helps us decide how many resources (people, machines, money) we need for each task. Think of it as deciding how many pizza slices to order for a party so everyone gets enough.

Network Diagrams – The Planning Super‑Hero 🛠️

A network diagram is a visual map that shows the sequence of tasks in a project. It’s like a flowchart for a recipe: you see which steps must happen before others.

Two Main Types

  • Activity on Node (AoN): Each node (box) is a task; arrows show the order.

  • Activity on Arrow (AoA): Each arrow is a task; nodes show the start/end points.

Key Terms

  1. Early Start (ES): The earliest a task can begin.

  2. Late Start (LS): The latest a task can begin without delaying the project.

  3. Slack (Float): The time a task can be delayed without affecting the finish date.

  4. Critical Path: The longest sequence of tasks; any delay here delays the whole project.

Example: Building a Model Car 🚗

Let’s plan a simple project to build a model car in a week.

TaskDuration (days)PredecessorsEarly StartLate StartSlack
Design Car Body2NoneDay 0Day 00
Paint Body1DesignDay 2Day 20
Build Wheels1DesignDay 2Day 42
Attach Wheels1Paint, Build WheelsDay 3Day 30
Test Drive1Attach WheelsDay 4Day 40

In this example, the critical path is Design → Paint → Attach Wheels → Test Drive (total 5 days). Any delay here pushes the final delivery date.

Calculating Total Cost with CPA 📈

Once we know the duration of each task, we can estimate the cost:

\$\text{Total Cost} = \sum{i=1}^{n} (\text{Duration}i \times \text{Cost per Day}_i)\$

Tips for Students

  • Use a color‑coded network diagram: green for non‑critical tasks, red for critical.

  • Practice with real projects: plan a school fair, a sports event, or a group assignment.

  • Check your slack – if a task has slack, you can use that time to double‑check or add extra features.

  • Remember: the critical path is the project’s backbone; keep it strong!

Quick Quiz 🎓

  1. What is the difference between Early Start and Late Start?

  2. Why is slack important in project planning?

  3. Identify the critical path in the model car example.