PHINN · Persistent Homology Inspired Neural Network

Train on the events that haven't happened yet.

PHINN synthesises realistic rare-event time series — conditioned on the topological fingerprint of a crisis — so your forecasting, risk and autonomy systems are ready for the tail before the tail arrives.

signal · window 128NOMINAL
The problem

Your models know calm weather. They've never met the storm.

The events that matter most — a geomagnetic superstorm, a cascading grid trip, a caster breakout, a sudden shift in adversary behaviour — are the ones with almost no data. Statistical and diffusion generators smooth them away. Matching moments isn't enough; you need to match the shape of a crisis.

Rare events leave a fingerprint in topology — characteristic transitions in Betti numbers that are more stable, more interpretable and more discriminative than statistical moments.

PHINN reads that fingerprint from the few real events you have, then generates thousands of new, structurally faithful scenarios to train, stress-test and price against.

How PHINN works

From signal to shape to scenario.

A conditional flow-matching generator, steered by dynamic Betti curves and held to the topology of real events by a differentiable persistence-landscape loss.

01 / EMBED

Sliding-window point clouds

Each window of the series is lifted into a point cloud — jointly across sensors and modalities.

02 / FILTER

Vietoris–Rips filtration

Grow neighbourhoods and watch features appear and vanish: components, loops, voids.

03 / FINGERPRINT

Dynamic Betti curves

β₀, β₁, β₂ over time — a compact, interpretable signature of how a crisis unfolds.

04 / GENERATE

Conditional flow matching

New scenarios are generated to hit target Betti curves, with H₁/H₂ consistency enforced in training.

Plain-language targetsDescribe the event — "sharp crash, fast recovery" — and an LLM-to-Betti layer sets the topology.
Multi-modal by designJoint filtrations across heterogeneous sensors, not one channel at a time.
Few-shot & cross-domainMeta-learning transfers structure across rare-event corpora when your own data is thin.
Benchmarked

Fidelity where it counts: in the shape of the tail.

Evaluated on financial-crisis, epidemiological and multi-modal time-series benchmarks against statistical and diffusion-based baselines.

41–63%
Lower β-RMSE

Topological error versus all statistical and diffusion baselines tested.

84%
Transition accuracy

Reproduces when a rare event begins and breaks — not just how big it gets.

≥ JD
Tail coverage

Matches jump-diffusion models on tail coverage while exceeding them on shape fidelity.

All reported results carry 95% confidence intervals. Source: Yusuf, Takahashi & Bhaduri, arXiv:2606.15452 (2026).

Applications

One engine. Four sectors where the tail is the whole story.

We started in defense and space. The same mathematics applies anywhere a rare, high-consequence event hides in sensor data.

Sector 01

Defense

Adversaries don't repeat the playbook you trained on. PHINN generates the anomalies, surges and shocks that sit outside the historical record — for test, evaluation and red-teaming.

Validation under way
  • Anomaly & threat-detection trainingSynthetic rare-signature data to harden detectors where real examples number in the single digits.
  • Pre-registered corridor testsForecast windows declared in advance and scored against what actually happens — evidence, not demos.
  • Supply-chain shock scenariosStress defense and aerospace supply chains against disruptions with the structure of past crises.
  • Robust autonomy & sensingEdge-case sensor streams for uncrewed systems, with certified robustness to adversarial perturbation.
Sector 02

Space

The space weather record holds only a handful of truly extreme storms. PHINN generates thousands of physically shaped variants — for operators, insurers and regulators who must plan for the next one.

Research & insurance pilots
  • Extreme space-weather scenariosSynthetic geomagnetic storm sequences beyond the observed record, conditioned on the topology of historic events.
  • Catalogue & custody riskModel how drag surges during major storms degrade orbit tracking and how long custody takes to recover.
  • Space-insurance portfolio stressAccumulation scenarios across a book of satellites for underwriting and capital planning.
  • Constellation operationsRehearse anomaly response and collision-avoidance load under storm conditions.
Sector 03

Steel

A breakout or furnace upset is rare, violent and expensive — and the plant historian holds only a few. PHINN turns those few into a training set large enough to catch the next one early.

Open to pilot partners
  • Caster breakout predictionSynthetic mould thermocouple patterns preceding sticker breakouts, to train early-warning models.
  • Blast-furnace upsetsHanging, slips and channelling scenarios generated across multiple sensor streams at once.
  • Refractory & equipment failureRare degradation-to-failure trajectories for predictive maintenance on high-value assets.
  • Energy & input-price shocksStress production planning against coking-coal, scrap and power price crises with realistic shape.
Sector 04

Power

Grids are engineered for the expected. Blackouts come from the unexpected — compound, cascading, fast. PHINN generates the cascades your planning models have never had to survive.

Open to pilot partners
  • Cascading-failure scenariosMulti-node outage sequences with the topology of real blackouts, for contingency and resilience planning.
  • Geomagnetically induced currentsStorm-driven GIC scenarios for transformer risk — linking our space-weather work directly to the grid.
  • Renewable ramp & frequency eventsRare wind and solar ramps and frequency excursions to size reserves and tune protection.
  • Asset failure & market stressTransformer and line failure trajectories, and price-spike scenarios for trading and hedging.
Why these four They're linked. Space weather drives grid currents; grid stress drives steel's energy costs; steel and energy feed the defense industrial base. A rare event in one is rarely contained to one — PHINN models them on a common topological footing.
Working with us

Prove it on your data first.

We earn trust with measurable results, not slideware. Every engagement starts with a test you design the scoring for.

Phase 1 · Weeks

Scoped validation

Pick a rare event that matters to you. We agree the success criteria up front — pre-registered, so nobody can move the goalposts.

Phase 2 · Months

Pilot

PHINN runs on your historical data and feeds your existing models, risk tools or test ranges. Results reported against the agreed criteria.

Phase 3 · Ongoing

Deploy & co-develop

Licensed deployment, on-prem or air-gapped where required, with joint research and publication where it serves both sides.

Research

Open science, proprietary engine.

The method is published for scrutiny. The production system, sector models and tooling are our IP.

arXiv:2606.15452 · cs.LG · math.AT · q-fin.RM · stat.ML · June 2026

PHINN: Persistent Homology Inspired Neural Network for Rare-Event Time Series Generation

Emre Yusuf, Ren Takahashi, Jayabrata Bhaduri — Defense.Codes
Read on arXiv ↗

In preparation: applied studies on extreme space weather and orbital catalogue custody, and pre-registered forecasting tests with defense partners.

Contact

Have a rare event you can't afford to miss? Let's put PHINN on it.

Briefings for defense, space, steel and power organisations, insurers and research partners.