Chapter 44 — Engineering capstone I

Chapter 44 — Engineering capstone I

Lesson map

Lesson 44 published. Map, example, EX130.

flowchart TD
  N0["Learning outcomes"]
  N1["44.1 Capstone choice"]
  N2["44.2 Scope and evaluation"]
  N3["44.3 Beginning implementation"]
  N4["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4
  N4 --> EX["Worked example"]
  EX --> Q["Exercise EX130"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["44.1 Capstone choice"]
  N2["44.2 Scope and evaluation"]
  N3["44.3 Beginning implementation"]
  N4["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX130"]

[Learning outcomes]
    |
    v
[44.1 Capstone choice]
    |
    v
[44.2 Scope and evaluation]
    |
    v
[44.3 Beginning implementation]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX130]

Learning outcomes

You will (1) define a capstone project; (2) plan scope and evaluation; (3) begin implementation.

44.1 Capstone choice

For his capstone, Jonas chooses to design and verify a community redemption feature: members can donate credits to a hardship fund that pays energy bills for households in difficulty, with the board approving payouts. The feature touches issuance, transfer, governance, privacy and member experience, which lets him demonstrate the whole engineering process. He writes a capstone brief with goals, stakeholders, constraints and success criteria, approved by Dr Nwosu and the board. He also lists the risks of the project and how he will manage them.

44.2 Scope and evaluation

The scope includes a fund contract, board approval through the existing multi-signature with a timelock, monthly public totals without naming recipients, and app changes. Evaluation criteria include requirements coverage, invariant tests, role policy conformance, a privacy review and a usability test with five members. Jonas excludes automatic payouts, which would require more complex rules, recording the reason. Clear scope and criteria make the capstone assessable and keep it achievable in the time available. Dr Nwosu confirms the criteria are measurable before work begins.

44.3 Beginning implementation

Jonas writes requirements and state models first, then a minimal fund contract on the test network. An early property test finds that donations could be made to the fund after it is paused, contrary to his model. He fixes the rule and adds the test permanently. He also drafts the privacy review, confirming that recipients are recorded only off-chain. Starting with models and tests continues the habits built over the degree and shows them working on a new problem. Progress is logged.

Worked example

The capstone brief defines a hardship fund with board-approved payouts; an early property test finds donations accepted while paused, which is fixed.

Synthetic case. The fund, members and tests are synthetic.

Errors and limits

Expanding capstone scope to include complex automatic payouts risks an unfinished, unverified result.

Exercises

• EX130 — Capstone feature. What feature does the capstone build? Rubric: 3 = a hardship fund from donated credits;; 2 = fund;; 1 = exchange;; 0 = none.
• EX131 — Excluded scope. What is excluded from scope? Rubric: 3 = automatic payouts;; 2 = automation;; 1 = donations;; 0 = none.
• EX132 — Early defect. What did the early property test find? Rubric: 3 = donations accepted while paused;; 2 = paused donations;; 1 = vague;; 0 = none.

Synthesis

A clearly scoped capstone with criteria and model-first implementation demonstrates the full engineering process.

Continue studying — chapter 44 of 50

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