Verification and validation

Continuous integration

Each model is checked against an independent reference before it is used: the CFD solver against Hagen–Poiseuille flow, the Haberman–Sayre wall-corrected Stokes drag and Johnson & Patel’s sphere wakes; the robot kinematics on 1,600+ checks; the warehouse layout against an independent FreeCAD model. The suites run in CI:

Tube Flow tests Cobot Lab tests Warehouse Model tests Tierwise tests

Each decision tool also carries its own test suite and validation notes in its folder of the portfolio repository. The chess tests are listed with the Lab.

Methods behind the offers

Formerly the Services page
Service 01

Dynamic Risk & Resilience Modeling

System dynamics

Problem
Static risk registers and heat maps score a threat once and freeze it. They can't show how a disruption compounds through delay, capacity limits, and the responses of the people and systems around it — which is usually where the real damage happens.
Approach
We build a system dynamics model of your network's disruption pathways — stocks, flows, and the feedback loops connecting them — calibrated against real network structure and, where available, historical reference modes.
Output
A working model, a set of early-warning indicators tied to it, and stress-test scenarios you can defend to a board or a regulator — not a one-time score.
Fits when
Your current risk process treats disruptions as independent events, or your resilience metrics haven't been able to explain why a "low probability" risk turned into a long-tail recovery.
Service 02

Network Design Optimization

MILP / stochastic programming

Problem
Facility, sourcing, and capacity decisions typically get optimized on landed cost alone. Resilience and flexibility show up afterward, as a qualitative overlay, which means they lose every time to a cheaper number.
Approach
Mixed-integer and stochastic optimization models that put a number on flexibility — deferral, expansion, dual-sourcing, switching — alongside cost, so the trade-off is explicit rather than assumed.
Output
Candidate network configurations with quantified cost-resilience trade-offs, sized for the capital allocation conversation you actually need to have.
Fits when
You're facing a re-sourcing, capacity expansion, or footprint decision and want the resilience value of each option priced, not asserted.
Service 03

Systems Diagnostics & Executive Workshops

Causal mapping / simulation

Problem
Teams routinely diagnose structural problems as behavioral ones — blaming a supplier, a planner, or "poor communication" for dysfunction that a system dynamics reading would trace to the structure itself. The bullwhip effect is the textbook case.
Approach
Facilitated causal loop mapping with your team, backed by simulation exercises — including live, game-based demonstrations — that let people feel the dynamic before they're asked to accept the diagnosis.
Output
A shared causal model your leadership team actually agrees on, and a clear read on which fixes are structural (durable) versus behavioral (temporary).
Fits when
You've tried the obvious fixes — more communication, tighter forecasts, new SOPs — and the same problem keeps resurfacing in a different form.

Decision tools

Full portfolio →

Global Disruption Atlas

Disruption decision lab on a 3D globe: live IMF PortWatch chokepoint data, sea-graph rerouting, min-cost flow re-planning, time-to-survive versus time-to-recover, a Monte Carlo and a 32-option flexibility portfolio.

Network Stress Test

Supply-network resilience sandbox: hundreds of editable nodes, a min-cost-flow solver, N-1 contingency scans, Monte Carlo stress tests and adversarial worst-case search.

Supply Pulse

System-dynamics simulator of a packaged food and dairy supply chain: QA holds, shelf life, hiring and a distant ingredient supplier; decision lab, play mode and a three-level tutorial; English, Spanish and Danish.

Lag Lab

Production and workforce model that splits post-step overshoot into refill, structure, policy and forecast, exactly.

Real Options for Network Design

Prices flexibility against a fair baseline over a binomial demand lattice: commit now, best fixed, wait and see, stage and expand, lease and break.

Tierwise

Multi-tier capacity planning: a time-phased requirements plan, exact tracing of load to markets, capacity to add, and planning within capacity as a linear program (HiGHS); a Network Studio and world map.

Clockspeed Balancing

Management flight simulator of the mismatch between commercial, supply chain and network clockspeeds (early development).

Warehouse Model

Warehouse design from first principles: a parametric FreeCAD model and an analytical model share one layout (proved identical on 400 designs), with simulation, total cost of ownership, an optimiser, and IFC / DXF / glTF export.

Network Design Visuals

A library of 17 network-design visualisations, from demand bars to O–D flow maps.

Research and open models

Publications: Journal of Simulation · NATO Science Series · Computers & Security

DDRA — dynamic cyber-risk model

A five-stock system-dynamics model of the attack–defence loop in a ship’s cyber-physical ballast system: detection delay decides containment or failure. Paper (SSRN).

Flexibility in Supply Chain

Companion tools for the book Engineering Flexibility in Supply Chain Design (repo).

Supply Chain Digital Twin

Capacity under a months-on-hand stock policy and end-to-end lead time across a multi-tier network (Streamlit).

Pharma supply chain ABM

An agent-based model of material through a contract-manufacturing chain (Mesa, Streamlit).

System dynamics models

Vensim models in public health, epidemiology and cyber-resilience.

Estay Dynamics website

The source of this site, including the Global Disruption Atlas and its tests.

Next step

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