AISE502/moodle/week_11.html

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     AISE502 · Moodle course page · Week 11
     Section title (Edit section → Section name): Week 11: The Fit III – Measurement Contract, Conway's Law, and the Limits of the Theory
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     corresponding 'Text and media area' (editor → source code view), or all three into one.
     The slide set of lecture 11 is added by the lecturer as a file resource below block 2.
     Generated by src/build_moodle.py from src/content/week_11.json – edit the JSON, not this file.
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<!-- BLOCK 1 · Learning objectives -->
<h4>🎯 Learning objectives</h4>
<ul>
  <li>I can explain why step (vii) codifies the chosen fit as a measurement contract of executable invariants.</li>
  <li>I can define an architectural fitness function, classify it by scope and cadence, and name the three instrument families.</li>
  <li>I know the four DORA metrics, the coupling finding, and why the evidence is prediction rather than causal proof.</li>
  <li>I can name the four layers of the cascade with their falsification questions and read the C10 reference contract.</li>
  <li>I can explain, using Boehm and Menzies, why the cost-of-change curve is flat within but steep across architecture boundaries.</li>
  <li>I can explain why fitness functions are the operating licence for agents and name the two Axis-B fitness-function types.</li>
  <li>I know which five measurement-contract items my project submission must ship, wired into CI.</li>
  <li>I can apply Conway's law as the third fit dimension: check D11 last but veto on it first.</li>
  <li>I know the four Team Topologies team types, the three interaction modes, and the inverse Conway manoeuvre.</li>
  <li>I can name the six limits of the theory, what compensates each, and state Maxim 9.</li>
</ul>

<!-- BLOCK 2 · Theory -->
<h4>🧑‍🏫 Theory</h4>
<p><strong>Lecture 11: The Fit III – The Measurement Contract, Conway's Law, and the Limits of the Theory</strong> · 3 lessons lecture + 1 lesson standup/coaching<br>
Part IV closes with the measurement contract in depth (fitness functions, DORA, C10 reference contract, cost of change), Conway's law as third fit dimension, and six limits of the theory.</p>
<ul>
  <li>Step (vii) codifies the chosen fit as a measurement contract of executable invariants: “the architecture may change freely as long as the contract stays green”.</li>
  <li>Fitness functions – objective integrity assessments – are classified by scope (atomic, holistic) and cadence (triggered, continual, temporal); three families: dependency checks as CI gates, performance and cost budgets, chaos experiments.</li>
  <li>The four DORA metrics – tempo: deployment frequency, lead time for changes; stability: change failure rate, failed-deployment recovery time – are not a trade-off: elite performers lead on all four.</li>
  <li>Loosely coupled architectures and teams are the strongest predictor of continuous delivery; the label “microservices” is neither necessary nor sufficient – survey-based prediction, not causal proof.</li>
  <li>The four-layer cascade – design time, delivery, operation, evolution – asks whether the structure is intact, delivering, keeping its runtime promises, ageing; the C10 reference contract instantiates it in eight rows.</li>
  <li>Boehm's cost-of-change escalation (up to one hundred times) is flattened for changes within an architecture (Menzies, 171 projects) but steep for changes of it – the contract, not the diagram, protects the investment.</li>
  <li>Fitness functions are the operating licence for agents (Axis A); Axis B adds two new fitness-function types with old mechanics: eval-harness pass rate (triggered) and token-cost budget per request (continual).</li>
  <li>The fit is three-way – pattern, application class, team structure; check D11 last but veto on it first; Team Topologies and the inverse Conway manoeuvre make Conway's law a design instrument.</li>
  <li>Six limits – ordinal scales, context-dependence, hybrids as the normal case, heterogeneous evidence, the hidden organisation, AI-era volatility – make the matrix a hypothesis, not an authority.</li>
  <li>Maxim 9: the matrix is the argument's skeleton, ATAM is its court of appeal, the ADR is its record, and the fitness function is its parole condition.</li>
</ul>
<p>📎 <strong>Materials:</strong> Slide set of Lecture 11 <em>(added below by the lecturer)</em> · Script: Part IV – Sections 37 (The Measurement Contract), 38 (The Third Fit Dimension: Conway's Law and Team Topologies) and 39 (Limits of the Theory – Applied to Itself).</p>

<!-- BLOCK 3 · Self-study and assignments -->
<h4>🧑‍💻 Self-study and assignments</h4>
<p><strong>📖 Reading before the lecture:</strong> Part IV – Sections 37 (The Measurement Contract), 38 (The Third Fit Dimension: Conway's Law and Team Topologies) and 39 (Limits of the Theory – Applied to Itself).</p>
<p><strong>Also before the lecture:</strong></p>
<ul>
  <li>Arrive with the deterministic core (Performance, Risk, Optimization services) tested against the reference vectors – week 11 completes M4 with resilience and graceful degradation.</li>
  <li>Have your project's measurement contract from the A2 dossier at hand – the lecture shows the C10 reference contract and what your submission must ship.</li>
</ul>
<p><strong>🧩 Exercise session:</strong> One lesson of standup/coaching: the teams complete the resilience patterns on all external calls and verify graceful degradation, closing milestone M4 at the end of the week.</p>
<p><strong>🛠️ Project work this week</strong> · Milestone M4 – Deterministic Core and Resilience (weeks 10–11)</p>
<ul>
  <li>Add resilience patterns to all external calls: timeout, retry, circuit breaker, fallback.</li>
  <li>Verify graceful degradation – the resilience row of the reference contract (kill one instance or broker under load; the SLO holds) is the fitness function that verifies it.</li>
  <li>Finish testing the Performance, Risk, and Optimization services fully against the reference vectors – milestone M4 closes at the end of week 11 with the deterministic core fully tested and resilient.</li>
  <li>Keep the deterministic core free of LLM calls – this is the line that is graded.</li>
  <li>Prepare for the project review: the submission must ship its measurement contract wired into CI – module-boundary check with zero violations (Python: import-linter; Java: ArchUnit or Spring Modulith), including the determinism-boundary rule; an eval harness with a versioned golden set and pass rate ≥ 95 %; a token-cost budget per request as a pipeline gate; a p95 latency budget ≤ 20 s for the advisory scenario; and the ADR (MADR form) whose final section is the contract. Be ready to demonstrate one contract violation being caught by CI.</li>
</ul>
<div style="border-left:4px solid #1b6ec2; background:#eef5fc; padding:8px 12px; margin:10px 0;">📌 <strong>Due this week:</strong> Milestone check (end of week 11): deterministic core fully tested and resilient</div>