Week 8 Tutorial: Trace the pad queue
Schedule a two-drone, one-pad case by hand, run the five-drone, two-pad case, and locate where shared charging changes the answer.
14 April 2027
Open Week 8 in the Lab →Try your own change on this week's case.
Two-hour tutorial: preparation, coding and checks
This week’s task#
Model: The main case has ten orders, five drones and two pads. A separate #01–#04 case has A/B and one pad. Corridor reservations are not active.
Before you start · 15 minutes#
Read W8. Work the symbolic request-at-5 example and explain when the earliest pad becomes free.
Trace the example · 25 minutes#
Compare one pad with two in the main case. This changes resource capacity: inspect the queue rather than presenting it as an algorithm-only improvement.
Implement and compare · 55 minutes#
Select the two-drone case in the controls and compute its queue by hand. Return to the main case, save a baseline and use myMigrations with the provided shared evaluator. Inspect the next task after a charge.
Use Open full Lab for editable inputs, strategy code, exports and the practice pack. The example on this page compares this week’s published cases; your local student runner must call the functions you complete.
Check and explain · 25 minutes#
Record request, charge start, charge end and the next departure. Add a capacity test and name the event that causes a delay to another drone.
What to keep: A2: shared-resource evaluation and the first checked fleet plan. Show the tutor your prediction, experiment and explanation for this week’s participation point; keep the record to develop your assignment.
Optional extension#
Keep capacity fixed and move a different order. A migration may leave some times unchanged; report the actual outcome.
W8 · Charging is a shared queue.
Which other drone is delayed when you move an order?
The same five drones share charging pads. Reduce two pads to one and inspect the queue it creates.
8/10 on time. Every order delivered and every drone returned with all checks passing.
Computed from this case · 13.42 ms · lab-1.0 · ten-orders
2 charging pads · one shared queue
| Drone / order | Requests pad | Starts charge | Wait |
|---|---|---|---|
| A #01 | 589 | 589 | 0 s |
| B #02 | 1071 | 1071 | 0 s |
| A #03 | 1483 | 1483 | 0 s |
| B #05 | 2067 | 2067 | 0 s |
| A #04 | 2269 | 2269 | 0 s |
| A #06 | 3634 | 3634 | 0 s |
| A #07 | 4772 | 4772 | 0 s |
Orange intervals are ground queues. A later charging start can delay the drone’s next order.
Explore the evidence, replay or open full Lab
Open full Lab ↗ for editable inputs, strategy code and saved comparisons.
The fleet and orders stay fixed; pad capacity changes. This is a model comparison, so inspect the queue before judging the totals.
Colour bands show ground elevation. The marked passage runs between two towers; its rule allows one drone at a time. Height shown at 3× scale.
Read the example above
The fleet and orders stay fixed; pad capacity changes. This is a model comparison, so inspect the queue before judging the totals.
Mixed fleet; complete trips · Shared charging, FCFS · Corridor reservations not active
| Inspect | Order | Drone | Load start | Deliver | Return | Late (s) | Energy (J) |
|---|---|---|---|---|---|---|---|
| #01 | A | 82 | 358 | 529 | 0 | 52958 | |
| #02 | B | 576 | 846 | 1011 | 0 | 56083 | |
| #03 | A | 1258 | 1393 | 1423 | 0 | 12529 | |
| #04 | A | 1642 | 1978 | 2209 | 0 | 76764 | |
| #05 | B | 1780 | 1946 | 2007 | 0 | 21712 | |
| #08 | B | 2879 | 3174 | 3364 | 0 | 63728 | |
| #06 | A | 3239 | 3459 | 3574 | 0 | 43225 | |
| #07 | A | 4180 | 4511 | 4712 | 405 | 80443 | |
| #09 | A | 5789 | 6038 | 6182 | 356 | 47704 | |
| #20 | D | 7758 | 8221 | 8579 | 0 | 194341 |
Play the recorded flight, or drag the time slider.
Time and shared resources
NowThe vertical line marks the current time; outlined intervals are active. Select an interval to jump to its start. Intervals include their start and exclude their end.
0 s 8639 s
Continue in the Lab →The same case, with every input open to change.
The spec
What you bring to the session. Written so a reader can tell whether it has been met without asking you.
- you can trace a delay from one drone's charging to another drone's departure
- queueing appears in your evaluation as a resource, not as a constant per drone
- your capacity test fails when a third drone is charged at once
Teaching team
- Kofi Marchetti — tutor