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FA-67406 / Elevator dispatch scheduling / Open access

Door dwell time calculation: nudging onset · case 01

The door keeps reopening on the third obstruction instead of nudging.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Nudging starts one reopen too late.

THE FAILURE

Nudging starts one reopen too late.

Unsuccessful approach: Suppressing nudging when nobody is counted keeps a nuisance obstruction reopening the door.

Case contract

Dwell time in deciseconds: base 40 for a hall call stop (or a stop with both hall and car calls), 25 for a car-call-only stop. Accessible mode extends the base by half (integer). Every passenger beyond the first adds 10. The result is capped at 150. From the third reopen onward the door nudges with a fixed dwell of 20.

Why this case matters

Lift group controllers make these decisions many times per minute; a wrong answer strands passengers, wastes trips or overrides a safety rule.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    base = 40 if x['call_type'] in ('hall', 'both') else 25
    if x['accessible']:
        base = base * 3 // 2
    pax = x['boarding'] + x['alighting']
    dwell = base + 10 * max(pax - 1, 0)
    dwell = min(dwell, 150)
    nudge = x['reopen_count'] > 3
    if nudge:
        dwell = 20
    return {'dwell_ds': dwell, 'nudge': nudge}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 12', {'call_type': 'car', 'boarding': 0, 'alighting': 4, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('control 1', {'call_type': 'both', 'boarding': 6, 'alighting': 3, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 4', {'call_type': 'hall', 'boarding': 5, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 100, 'nudge': False}), ('control 7', {'call_type': 'both', 'boarding': 5, 'alighting': 1, 'reopen_count': 4, 'accessible': True}, {'dwell_ds': 20, 'nudge': True})], [('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 39', {'call_type': 'car', 'boarding': 3, 'alighting': 3, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('boundary: nobody boards or alights', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 25, 'nudge': False}), ('boundary: crowd exceeds the cap', {'call_type': 'hall', 'boarding': 8, 'alighting': 8, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 150, 'nudge': False}), ('sampled regression 12', {'call_type': 'car', 'boarding': 0, 'alighting': 4, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 15', {'call_type': 'hall', 'boarding': 2, 'alighting': 5, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('control 18', {'call_type': 'car', 'boarding': 8, 'alighting': 7, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 150, 'nudge': False})], [('regression: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: crowd exceeds the cap', {'call_type': 'hall', 'boarding': 8, 'alighting': 8, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 150, 'nudge': False}), ('boundary: single passenger', {'call_type': 'hall', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 40, 'nudge': False}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('control 23', {'call_type': 'hall', 'boarding': 7, 'alighting': 3, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 130, 'nudge': False}), ('control 26', {'call_type': 'both', 'boarding': 3, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 110, 'nudge': False}), ('sampled regression 29', {'call_type': 'both', 'boarding': 1, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 28', {'call_type': 'car', 'boarding': 1, 'alighting': 3, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: single passenger', {'call_type': 'hall', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 40, 'nudge': False}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('control 34', {'call_type': 'hall', 'boarding': 3, 'alighting': 5, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('control 37', {'call_type': 'hall', 'boarding': 4, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 40', {'call_type': 'car', 'boarding': 1, 'alighting': 8, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 54', {'call_type': 'both', 'boarding': 2, 'alighting': 7, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('control 45', {'call_type': 'both', 'boarding': 6, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 48', {'call_type': 'hall', 'boarding': 3, 'alighting': 8, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 140, 'nudge': False}), ('control 51', {'call_type': 'hall', 'boarding': 2, 'alighting': 4, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 90, 'nudge': False})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: third reopen{'dwell_ds': 50, 'nudge': False}{'dwell_ds': 20, 'nudge': True}Failed
regression: third reopen with nobody moving{'dwell_ds': 25, 'nudge': False}{'dwell_ds': 20, 'nudge': True}Failed
sampled regression 12{'dwell_ds': 55, 'nudge': False}{'dwell_ds': 20, 'nudge': True}Failed
boundary: stop with hall and car calls{'dwell_ds': 50, 'nudge': False}{'dwell_ds': 50, 'nudge': False}Passed
boundary: accessible car call stop{'dwell_ds': 37, 'nudge': False}{'dwell_ds': 37, 'nudge': False}Passed
control 1{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed
control 4{'dwell_ds': 100, 'nudge': False}{'dwell_ds': 100, 'nudge': False}Passed
control 7{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed

SHA-256 / 93a0cdbc5f647259d8edabe8f758eb3b54abfe5a0e20b5c967d9365fd6fffa4c

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    base = 40 if x['call_type'] in ('hall', 'both') else 25
    if x['accessible']:
        base = base * 3 // 2
    pax = x['boarding'] + x['alighting']
    dwell = base + 10 * max(pax - 1, 0)
    dwell = min(dwell, 150)
    nudge = x['reopen_count'] >= 3 and pax > 0
    if nudge:
        dwell = 20
    return {'dwell_ds': dwell, 'nudge': nudge}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 12', {'call_type': 'car', 'boarding': 0, 'alighting': 4, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('control 1', {'call_type': 'both', 'boarding': 6, 'alighting': 3, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 4', {'call_type': 'hall', 'boarding': 5, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 100, 'nudge': False}), ('control 7', {'call_type': 'both', 'boarding': 5, 'alighting': 1, 'reopen_count': 4, 'accessible': True}, {'dwell_ds': 20, 'nudge': True})], [('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 39', {'call_type': 'car', 'boarding': 3, 'alighting': 3, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: accessible busy hall stop', {'call_type': 'hall', 'boarding': 5, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 130, 'nudge': False}), ('boundary: nobody boards or alights', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 25, 'nudge': False}), ('boundary: crowd exceeds the cap', {'call_type': 'hall', 'boarding': 8, 'alighting': 8, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 150, 'nudge': False}), ('sampled regression 12', {'call_type': 'car', 'boarding': 0, 'alighting': 4, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 15', {'call_type': 'hall', 'boarding': 2, 'alighting': 5, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 100, 'nudge': False}), ('control 18', {'call_type': 'car', 'boarding': 8, 'alighting': 7, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 150, 'nudge': False})], [('regression: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: crowd exceeds the cap', {'call_type': 'hall', 'boarding': 8, 'alighting': 8, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 150, 'nudge': False}), ('boundary: single passenger', {'call_type': 'hall', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 40, 'nudge': False}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('control 23', {'call_type': 'hall', 'boarding': 7, 'alighting': 3, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 130, 'nudge': False}), ('control 26', {'call_type': 'both', 'boarding': 3, 'alighting': 3, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 110, 'nudge': False}), ('sampled regression 29', {'call_type': 'both', 'boarding': 1, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 28', {'call_type': 'car', 'boarding': 1, 'alighting': 3, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: single passenger', {'call_type': 'hall', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 40, 'nudge': False}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('control 34', {'call_type': 'hall', 'boarding': 3, 'alighting': 5, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 110, 'nudge': False}), ('control 37', {'call_type': 'hall', 'boarding': 4, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 40', {'call_type': 'car', 'boarding': 1, 'alighting': 8, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True})], [('regression: third reopen', {'call_type': 'hall', 'boarding': 2, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('regression: third reopen with nobody moving', {'call_type': 'car', 'boarding': 0, 'alighting': 0, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('sampled regression 54', {'call_type': 'both', 'boarding': 2, 'alighting': 7, 'reopen_count': 3, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('boundary: stop with hall and car calls', {'call_type': 'both', 'boarding': 1, 'alighting': 1, 'reopen_count': 0, 'accessible': False}, {'dwell_ds': 50, 'nudge': False}), ('boundary: accessible car call stop', {'call_type': 'car', 'boarding': 1, 'alighting': 0, 'reopen_count': 0, 'accessible': True}, {'dwell_ds': 37, 'nudge': False}), ('control 45', {'call_type': 'both', 'boarding': 6, 'alighting': 0, 'reopen_count': 4, 'accessible': False}, {'dwell_ds': 20, 'nudge': True}), ('control 48', {'call_type': 'hall', 'boarding': 3, 'alighting': 8, 'reopen_count': 2, 'accessible': False}, {'dwell_ds': 140, 'nudge': False}), ('control 51', {'call_type': 'hall', 'boarding': 2, 'alighting': 4, 'reopen_count': 1, 'accessible': False}, {'dwell_ds': 90, 'nudge': False})]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: third reopen{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed
regression: third reopen with nobody moving{'dwell_ds': 25, 'nudge': False}{'dwell_ds': 20, 'nudge': True}Failed
sampled regression 12{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed
boundary: stop with hall and car calls{'dwell_ds': 50, 'nudge': False}{'dwell_ds': 50, 'nudge': False}Passed
boundary: accessible car call stop{'dwell_ds': 37, 'nudge': False}{'dwell_ds': 37, 'nudge': False}Passed
control 1{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed
control 4{'dwell_ds': 100, 'nudge': False}{'dwell_ds': 100, 'nudge': False}Passed
control 7{'dwell_ds': 20, 'nudge': True}{'dwell_ds': 20, 'nudge': True}Passed

SHA-256 / 10b7400f2300d667670be7d23d02c7c06e11707a86d6c334684c8b9f9d0ebb1c

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This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

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Verification & scope

Stipulated toy lift-control contract for a bounded teaching model; it makes no claim of conformance to any lift code or vendor dispatcher and omits real safety cases. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:47:52.622107+00:00.

Case digest / a57e560055396e38a22db7bbf1efeef5ea2d5b145f748e5ea6706df1454b70ed