Konjugate Logistics: model a supply network on a map

A supply chain manager's questions tend to start with "what if". What if my supplier is short for ten days? What if the highway floods? What if the strait closes? Konjugate Logistics is a toolbox for asking them on a model of your own network: suppliers, ports, warehouses and stores placed on a real map, joined by the roads and vehicles that actually carry the goods, and run through time so you can see what a disruption costs and what would have helped.

It is in early development, and this page says what it does today. It is the companion to a video series, Break It Before the World Does, which takes one question in a different city in each episode.

Getting it

Open Konjugate's Extensions dialog, go to Discover and install Konjugate Logistics Toolbox. It is one entry that installs two packages: a component library plugin and the add-on window that builds models from it. "Installing add-ons and plugins" walks through the dialog. Afterwards a Logistics button appears in the toolstrip.

A network on a map

The Logistics window starts from a map. Search for a city or region and Load roads, and it draws that area's roads from OpenStreetMap, and nothing else until you ask. The first load of a large area can take a few minutes. It is kept on your computer afterwards, so the same area opens at once the next time.

On the map you place the pieces of a supply network by clicking: suppliers, ports, warehouses, stores, dark stores and customer areas. Sites snap to the nearest road, and the links between them follow the roads. Each site has its own storage and stock cover, and each link has its own vehicles. You can also load a table of sites from a CSV file.

Public data helps, but it never decides for you. The window can look up ports, warehouses and towns near your map and show them as suggestions. A suggestion is only a ghost on the map until you adopt it. Where a number comes from is always shown: yours, assumed, or taken from a named source. Nothing is added to your network on its own.

When the network looks right, Build model turns it into a runnable Konjugate model, and Show in Konjugate opens that model on the canvas, where you can inspect every node and relationship the toolbox created.

Asking what if

A Scenario is a disruption applied to the network from a given day, run beside a baseline of the same days with no trouble. The toolbox offers disruptions such as:

• A chokepoint disrupted: a strait or canal carries fewer ships for a while, and you choose how much of the cargo is diverted elsewhere.
• A supplier short or late: one supplier makes much less for some days, and its warehouses either wait for it or order what it cannot make from others.
• The weakest link, ranked: each supplier and warehouse is failed on its own, for the same days, and ranked by what it costs.

The result is a comparison, not a verdict. It gives the share of demand met, sales lost, goods wasted and the running costs of transport, fleet and holding, scenario against baseline, and a run can be set beside an earlier one to see the difference between two choices.

The ranking has to be read carefully. It says what each failure costs in this model. It does not say how likely each failure is, and which is likeliest is not the model's to say.

What the model underneath does

Underneath, a network is a set of stocks and flows that Konjugate integrates through time. Containers and trucks are conserved by construction: what leaves one node enters the next, and each lane's idle, loaded and returning trucks always add up to its fleet. A supplier short of capacity delivers late, not never. A warehouse orders up to its stock cover target but never beyond the room it has. A store's opening hours shape its demand, and a lane's loading follows the hours of the sites at its ends.

A network placed in the toolbox counts pallets, and a port's containers count as ten pallets each, an assumption you can change. Rates are entered per day, and the vehicle types, with their capacity, cost and loading time, are defined once and shared by every lane that uses them. "Sharing one parameter across relationships" explains that mechanism.

Honest about where it is

The toolbox is early. The demonstration networks in the series use real places and real public data where it exists, and invented stores and suppliers, and each episode says which is which. The sizes of effects in a demonstration are chosen to make a point, not measured from a company. The figures in any run belong to that model's assumptions, so the useful question is how much a result moves when an assumption does.

Where to go from here

The series, Break It Before the World Does, is on YouTube. It opens on Dubai and the closing of the Strait of Hormuz, then shows how to build your own network in your own city. Its source and the toolbox's documentation live in the toolbox's repository, and "Forking a run to try a what-if" shows a related idea, branching one run to compare a change, in Konjugate itself.