FA-12041 / Sensor fusion consistency / Open access

Arrival time makes an old measurement look fresh · case 01

Delayed sensor samples enter the current fusion window.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Freshness uses receipt time instead of acquisition time.

THE FAILURE

Freshness uses receipt time instead of acquisition time.

Unsuccessful approach: A one-sided age test accepts future acquisition times.

Case contract

Return IDs in input order whose acquisition timestamp is between now-window and now inclusive. Records are (ID, acquired, arrived); window is nonnegative.

Why this case matters

Deterministic sensor-fusion model isolating one consistency contract; no hardware or production estimator is simulated.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(records, now, window):
    return [i for i,a,r in records if 0 <= now-r <= window]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('delayed stale sample', solve([('a',N,10+N)],10+N,2), [])
check('future clock sample', solve([('a',11+N,10+N)],10+N,2), [])
check('old boundary', solve([('a',8+N,10+N)],10+N,2), ['a'])
check('current acquisition', solve([('a',10+N,10+N)],10+N,0), ['a'])
check('stable order', solve([('b',9+N,10+N),('a',10+N,10+N)],10+N,2), ['b','a'])
check('empty window input', solve([],N,0), [])
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 fixture	Actual	Expected	Outcome
delayed stale sample	`['a']`	`[]`	Failed
future clock sample	`['a']`	`[]`	Failed
old boundary	`['a']`	`['a']`	Passed
current acquisition	`['a']`	`['a']`	Passed
stable order	`['b', 'a']`	`['b', 'a']`	Passed
empty window input	`[]`	`[]`	Passed

SHA-256 / 06d3a2c87595e3b972381d7e3a0f324bc64ed9ade1b4a1e61d71031298f8ddec

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
N = 1
observations = []
def solve(records, now, window):
    return [i for i,a,r in records if now-a <= window]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('delayed stale sample', solve([('a',N,10+N)],10+N,2), [])
check('future clock sample', solve([('a',11+N,10+N)],10+N,2), [])
check('old boundary', solve([('a',8+N,10+N)],10+N,2), ['a'])
check('current acquisition', solve([('a',10+N,10+N)],10+N,0), ['a'])
check('stable order', solve([('b',9+N,10+N),('a',10+N,10+N)],10+N,2), ['b','a'])
check('empty window input', solve([],N,0), [])
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 fixture	Actual	Expected	Outcome
delayed stale sample	`[]`	`[]`	Passed
future clock sample	`['a']`	`[]`	Failed
old boundary	`['a']`	`['a']`	Passed
current acquisition	`['a']`	`['a']`	Passed
stable order	`['b', 'a']`	`['b', 'a']`	Passed
empty window input	`[]`	`[]`	Passed

SHA-256 / 51c4a845c619c06464369406246ce5f85b7e0dbac36b7637d56e8d26a8f167c2

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 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.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

Exact small scalar or two-axis models; no nonlinear dynamics, numerical conditioning, or real sensor noise simulation. 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 2026-09-29T14:38:53.285774+00:00.

Case digest / ad887c70e8096c3248f0e21aa5d1e9c04144bb1af3ead4348f66610a5d555ae1