A supplied screening queue model: more coverage raises load, extra capacity reduces waiting
Supplied research · Reviewed findings · 30 October 2026
Incoprea Research · Supplied findings II · 30 October 2026
Evidence status: Reproduced conditional queue simulation; no false-positive, detection, safety or real staffing validation.
In a supplied queue simulation, selecting more arriving items for inspection increases waiting when staffing stays fixed. At 99% coverage, increasing parallel servers from 40 to 45 sharply reduces the simulated delay. The result is reproducible, but the source’s claim that 99% coverage becomes stable only above 40 servers is incorrect: 40 already gives a nominal load below one.
The hypothesis and the tested part
Screening Trades Flow for Safety links inspection coverage, false positives and clearance time. The supplied code tests only coverage and queue capacity. Each arrival is selected randomly with a fixed probability; there is no evidence threshold, risk score, true threat status, false-positive rate or detection outcome.
The numerical finding therefore concerns waiting for a generic inspection. It cannot establish the original false-positive mechanism or show that a real biosecurity system is safe, effective, or adequately staffed.
What the supplied simulation implements
The source specifies 600 arrivals per hour and four-minute service at each identical parallel server. It generates independent Poisson arrival counts for each minute, then places all of that minute’s items at the same minute timestamp. This is a minute-batched implementation, not continuous, individually timed Poisson arrivals. Selected items are scheduled with the earliest available server; unselected items bypass inspection.
Each scenario covers 480 hours, or 20 days, starting with every server free. The supplied sweep contains 24 combinations of four server counts and six coverage levels. A separate capacity section adds seven scenarios at 99% coverage, making 31 scenarios in total. They use successive draws from one generator seeded 20261030; they are not 31 replications of one condition.
Selected-item waiting, not total clearance
The reported mean and 95th percentile include all selected items, including those with zero queue delay. They exclude unselected items. They measure arrival-to-start waiting, not completion time: every selected item still requires four minutes of service afterward.
The counter named n_inspected records selected items scheduled for service. Some final scheduled starts or completions can lie beyond the 20-day arrival window. It is not a verified count of inspections completed by the deadline. A 400,000-selected-item stop guard exists, but no supplied scenario reaches it; the largest count is 286,044.
| Servers | Coverage | Nominal load | Mean wait before service | 95th-percentile wait |
|---|---|---|---|---|
| 40 | 90% | 0.90 | 0.223 min | 1 min |
| 40 | 95% | 0.95 | 0.698 min | 3 min |
| 40 | 99% | 0.99 | 4.858 min | 17 min |
| 45 | 99% | 0.88 | 0.129 min | 1 min |
These figures are from the supplied main sweep. Adding five servers increases nominal service capacity by 12.5%. Waiting becomes much smaller, but it does not disappear. Including inspection time, the corresponding 99%-coverage mean time for selected items is about 8.858 minutes with 40 servers and 4.129 with 45.
Correcting the stability arithmetic
With coverage c, expected selected arrivals are 600c per hour. Each server can perform 15 four-minute inspections per hour. Nominal utilization is therefore 600c/(15N)=40c/N.
At c=0.99 the offered workload is 39.6 fully occupied servers. Forty gives utilization 0.99; 45 gives 0.88. Forty already satisfies the below-unit-load condition. Additional headroom can improve delay performance, but “stable” and “short waits” are different claims. The supplied capacity section also reports a mean below its stated ten-minute target at 40 servers, so it does not establish a requirement for more than 40.
Finite-run limits
No warmup period is discarded and no steady-state convergence check or uncertainty interval is supplied. Near saturation, the initial empty system and finite window matter. The package itself contains two separately generated 40-server, 99%-coverage scenarios: one reports mean wait 4.858 minutes and a 17-minute 95th percentile, while the other gives 3.836 and 10 minutes. Neither is a universal stationary value.
Minute batching, deterministic service, constant arrival intensity, unlimited waiting space, random coverage and absence of breaks, failures, priorities or departures further limit transfer to practice. A reported zero 95th percentile elsewhere in the sweep also does not imply every item has zero delay.
Context and provenance
Larson and Odoni’s queueing definitions distinguish queue waiting from total system time. Dai and He’s parallel-server analysis provides established context for capacity, utilization and service quality; its analytical formulas are not substituted for this different batched model.
The supplied Incoprea package credits DeepSeek Harness with the analysis, code and drafting. Codex audited it, ran the unchanged script in an isolated copy, obtained a byte-identical result file, and prepared this corrected text. This reproduces supplied computation, not a new study or external peer review. The original hypothesis remains unchanged at Incoprea Research.
Inspect and reproduce the supplied result
Python 3 and NumPy. The script writes queue.json beside itself. Save the complete code as reproduce.py in a new folder and run python3 reproduce.py. This is a check of a supplied study, not a newly designed test.
Show the complete runnable reproduction
# Portable publisher copy: only ROOT/output pathname adapted; algorithm,
# parameter grid, seed and order are identical to the supplied original.
# Requires NumPy. Run: python3 reproduce.py ; writes queue.json beside script.
"""V20 #28 'Screening Trades Flow for Safety': coverage, capacity and clearance time."""
import json, os
import numpy as np
ROOT=os.path.dirname(os.path.abspath(__file__))
rng=np.random.default_rng(20261030)
LAM=600.0; SERVICE=4/60.0; HOURS=24*20
COVERAGES=[0.5,0.7,0.8,0.9,0.95,0.99]
def simulate(cov,N):
# Poisson arrivals by minute; deterministic 4-min inspection on N parallel servers
n_min=int(HOURS*60); arrivals=rng.poisson(LAM/60.0,n_min)
queue=[]; servers=np.zeros(N); waits=[]; done=0
t=0.0
for m in range(n_min):
for _ in range(arrivals[m]):
if rng.random()<cov:
# schedule: earliest free server
j=int(np.argmin(servers))
start=max(servers[j],m*1.0)
wait=start-m*1.0
servers[j]=start+SERVICE*60
waits.append(wait)
if len(waits)>400000: break
waits=np.array(waits)
return dict(coverage=cov,N=N,n_inspected=int(len(waits)),
mean_wait_min=float(waits.mean()) if len(waits) else None,
p95_wait_min=float(np.percentile(waits,95)) if len(waits) else None,
load=float(LAM*cov*SERVICE/N))
out={'design':{'arrivals_per_hour':LAM,'service_min':SERVICE*60,'hours':HOURS,'inspectors':None},'sweep':[],'capacity':[]}
for N in [40,45,50,60]:
for c in COVERAGES:
r=simulate(c,N); out['sweep'].append(r)
print(f"N={N} cov={c} load={r['load']:.2f} mean_wait={r['mean_wait_min']:.1f}min p95={r['p95_wait_min']:.1f}")
# minimum N for 99% coverage and mean wait under 10 min
for N in [40,41,42,44,46,48,50]:
r=simulate(0.99,N); out['capacity'].append(r)
print('capacity',r)
json.dump(out,open(os.path.join(ROOT,'queue.json'),'w'),indent=2)
Show the published results
{
"design": {
"arrivals_per_hour": 600.0,
"service_min": 4.0,
"hours": 480,
"inspectors": null
},
"sweep": [
{
"coverage": 0.5,
"N": 40,
"n_inspected": 144138,
"mean_wait_min": 6.937795723542716e-06,
"p95_wait_min": 0.0,
"load": 0.5
},
{
"coverage": 0.7,
"N": 40,
"n_inspected": 202128,
"mean_wait_min": 0.005664727301511913,
"p95_wait_min": 0.0,
"load": 0.7
},
{
"coverage": 0.8,
"N": 40,
"n_inspected": 230094,
"mean_wait_min": 0.034703208254017924,
"p95_wait_min": 0.0,
"load": 0.8
},
{
"coverage": 0.9,
"N": 40,
"n_inspected": 259318,
"mean_wait_min": 0.22296176894777842,
"p95_wait_min": 1.0,
"load": 0.9
},
{
"coverage": 0.95,
"N": 40,
"n_inspected": 273868,
"mean_wait_min": 0.6979749368308821,
"p95_wait_min": 3.0,
"load": 0.95
},
{
"coverage": 0.99,
"N": 40,
"n_inspected": 284841,
"mean_wait_min": 4.85812084636692,
"p95_wait_min": 17.0,
"load": 0.99
},
{
"coverage": 0.5,
"N": 45,
"n_inspected": 144259,
"mean_wait_min": 0.0,
"p95_wait_min": 0.0,
"load": 0.4444444444444444
},
{
"coverage": 0.7,
"N": 45,
"n_inspected": 201998,
"mean_wait_min": 0.0003564391726650759,
"p95_wait_min": 0.0,
"load": 0.6222222222222222
},
{
"coverage": 0.8,
"N": 45,
"n_inspected": 230650,
"mean_wait_min": 0.004617385649252114,
"p95_wait_min": 0.0,
"load": 0.7111111111111111
},
{
"coverage": 0.9,
"N": 45,
"n_inspected": 259397,
"mean_wait_min": 0.028735875896791406,
"p95_wait_min": 0.0,
"load": 0.8
},
{
"coverage": 0.95,
"N": 45,
"n_inspected": 273192,
"mean_wait_min": 0.059126914404521363,
"p95_wait_min": 1.0,
"load": 0.8444444444444444
},
{
"coverage": 0.99,
"N": 45,
"n_inspected": 284925,
"mean_wait_min": 0.12930420286040187,
"p95_wait_min": 1.0,
"load": 0.88
},
{
"coverage": 0.5,
"N": 50,
"n_inspected": 143810,
"mean_wait_min": 0.0,
"p95_wait_min": 0.0,
"load": 0.4
},
{
"coverage": 0.7,
"N": 50,
"n_inspected": 201936,
"mean_wait_min": 2.9712384121701924e-05,
"p95_wait_min": 0.0,
"load": 0.56
},
{
"coverage": 0.8,
"N": 50,
"n_inspected": 231226,
"mean_wait_min": 0.00026813593627014265,
"p95_wait_min": 0.0,
"load": 0.64
},
{
"coverage": 0.9,
"N": 50,
"n_inspected": 258964,
"mean_wait_min": 0.004282448525663798,
"p95_wait_min": 0.0,
"load": 0.72
},
{
"coverage": 0.95,
"N": 50,
"n_inspected": 274556,
"mean_wait_min": 0.009790352423549293,
"p95_wait_min": 0.0,
"load": 0.76
},
{
"coverage": 0.99,
"N": 50,
"n_inspected": 284713,
"mean_wait_min": 0.017947898409977767,
"p95_wait_min": 0.0,
"load": 0.792
},
{
"coverage": 0.5,
"N": 60,
"n_inspected": 144583,
"mean_wait_min": 0.0,
"p95_wait_min": 0.0,
"load": 0.3333333333333333
},
{
"coverage": 0.7,
"N": 60,
"n_inspected": 202166,
"mean_wait_min": 0.0,
"p95_wait_min": 0.0,
"load": 0.4666666666666667
},
{
"coverage": 0.8,
"N": 60,
"n_inspected": 230539,
"mean_wait_min": 0.0,
"p95_wait_min": 0.0,
"load": 0.5333333333333333
},
{
"coverage": 0.9,
"N": 60,
"n_inspected": 258698,
"mean_wait_min": 1.5462044546150336e-05,
"p95_wait_min": 0.0,
"load": 0.6
},
{
"coverage": 0.95,
"N": 60,
"n_inspected": 273353,
"mean_wait_min": 5.12158271538999e-05,
"p95_wait_min": 0.0,
"load": 0.6333333333333333
},
{
"coverage": 0.99,
"N": 60,
"n_inspected": 285210,
"mean_wait_min": 0.00026647032011500296,
"p95_wait_min": 0.0,
"load": 0.66
}
],
"capacity": [
{
"coverage": 0.99,
"N": 40,
"n_inspected": 284772,
"mean_wait_min": 3.836451617434298,
"p95_wait_min": 10.0,
"load": 0.99
},
{
"coverage": 0.99,
"N": 41,
"n_inspected": 286044,
"mean_wait_min": 1.2945106347275244,
"p95_wait_min": 4.0,
"load": 0.9658536585365854
},
{
"coverage": 0.99,
"N": 42,
"n_inspected": 285114,
"mean_wait_min": 0.5619331214882468,
"p95_wait_min": 2.0,
"load": 0.9428571428571428
},
{
"coverage": 0.99,
"N": 44,
"n_inspected": 285272,
"mean_wait_min": 0.17994755882105498,
"p95_wait_min": 1.0,
"load": 0.9
},
{
"coverage": 0.99,
"N": 46,
"n_inspected": 285032,
"mean_wait_min": 0.08470277021527407,
"p95_wait_min": 1.0,
"load": 0.8608695652173913
},
{
"coverage": 0.99,
"N": 48,
"n_inspected": 284156,
"mean_wait_min": 0.03578316136206872,
"p95_wait_min": 0.0,
"load": 0.8250000000000001
},
{
"coverage": 0.99,
"N": 50,
"n_inspected": 284491,
"mean_wait_min": 0.017441676538097865,
"p95_wait_min": 0.0,
"load": 0.792
}
]
}Show provenance and review boundaries
{
"source_folder": "Incoprea Hypothesis Tests II - 2026-10-30",
"source_code_sha256": "2af237963a5f56b1630a45b083307b68cc21396376961c2d4fbdb9f8186fe03f",
"source_result_sha256": "358379d01463ff48add8420e7e819c1ceb027ecb1a75d85d60c3acc940f2feae",
"review": "Unchanged supplied code regenerated a byte-identical result; portable copy changes output location only",
"scope": "Conditional finite queue simulation, not a measured inspection or safety system",
"runtime": "Review used Python3.14 and NumPy2.5.4",
"limits": "Minute-batched arrivals; waiting only among selected scheduled items; no warmup or repeated-run interval; no false-positive or detection data"
}Supplied analysis, code and initial drafting: DeepSeek Harness, as identified in the package. Consistency review, reproduction and corrected publication text: Codex. Internal computational review is not external peer review. Incoprea Research · Original posted question or hypothesis.
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