Logistics, Operations & Supply Chain¶

23 domain-specific abstractions whose origin domain is Logistics, Operations & Supply Chain.

Available-to-Promise — Gate every new delivery commitment against a date-bucketed residual curve — on-hand plus scheduled receipts minus prior promises — so a request is accepted only if no future bucket goes negative, distinguishing what is physically present from what is contractually free.
Backorder — The fulfilment arrangement in which an order is accepted as a binding obligation despite a stock-out, becoming a queued claim against future supply tracked in a visible ledger and clocked against an estimated resupply, rather than being refused as a lost sale.
Bellman Equation — The recursive optimality condition V(s) = max over a of [R(s,a) + γ·E V(s')] that reframes a sequential decision problem as a fixed point in value space, collapsing a combinatorial search over policy sequences into a solvable |S|-dimensional problem.
Cross-Docking — The distribution practice of unloading, re-sorting by destination, and reloading inbound freight straight onto outbound vehicles with zero dwell — casting the facility as a sorter rather than a warehouse, governed by schedule synchronization rather than inventory level.
Customs-Clearance Delay — The cross-border failure mode in which a physically ready shipment is held immobile because a sovereign clearance authority has not yet issued the release token — a permission-gate bottleneck immune to transport remedies, with queueing dynamics and a linear-then-catastrophic cost.
Economic Order Quantity — Find the replenishment batch size minimizing total cost by summing a per-event ordering cost that falls with batch size and a per-unit-time holding cost that rises with it, giving a U-shaped curve whose flat-bottomed optimum is √(2DK/h).
Just-in-Time — Replenish each production stage only when the next one consumes its input, deliberately shrinking buffers so disruption propagates instead of hiding — a coupling that pays off only when paired with the variability-reduction work that earns it.
Make-to-Order — Begin conversion of inputs into a finished good only after a confirmed customer order, placing the forecast-driven/order-driven decoupling point as far upstream as it will go so finished-goods inventory vanishes and the customer absorbs the full conversion-cycle wait.
Make-to-Stock — Produce finished goods ahead of any order against an aggregate forecast, placing the decoupling point as far downstream as it will go, so customer wait collapses to the order-to-pick interval at the price of holding cost and a binding forecast bet.
Milk Run — Consolidate many small point-to-point shipments into one high-utilization loop by running a single vehicle on a fixed scheduled circuit of pickup points, trading routing flexibility for an arrival window each point can plan around.
Min–Max Inventory — An inventory policy that manages stock inside a declared band — replenishing up to a maximum ceiling only once on-hand falls to a minimum reorder point, and doing nothing in between — collapsing continuous order decisions into two scalars per item.
Order-Batching Distortion — The supply-chain failure in which a lumpy ordering rule converts smooth downstream consumption into artificial order spikes and troughs, which each upstream tier misreads as real demand and amplifies — one of the four canonical causes of the bullwhip effect.
Perfect Order — Read fulfillment quality as one customer-facing scalar — the product of complete, on-time, undamaged, and correctly-documented sub-rates — so multiplicative decay (four links at 95% giving 81%) becomes visible and the binding sub-rate is read off directly.
Phantom Inventory — Diagnose a fulfilment miss against a record showing healthy stock as an information-state failure — the record overstating reality between audits — that silently suppresses replenishment, pointing the fix at reconciliation cadence rather than the pick face.
Plan-Execute Gap — The pathology in which a coarse-grained planning artefact cannot be enacted because the execution layer faces binding fine-grained constraints the planning model never represented — so the fix is constraint propagation and feedback, never a better forecast.
Returns Friction — Diagnose why returns, recalls, and repairs move badly: the reverse flow is an irregular trickle of heterogeneous, quality-uncertain units forced through a network designed and optimized for one-directional forward flow, sharing its rails as an afterthought.
Reverse Logistics — Manage the backward flow of goods from consumption toward recovery through one invariant pipeline — receive, inspect-and-grade, route, settle — where the triage sorts each unit up a value gradient and the constraints invert the forward chain.
Service Level — Commit in advance to fulfilling a stated quantile of stochastic demand — not its average — within a stated window with a breach consequence, and size the system's buffer against that tail, so each additional nine costs disproportionately more reserve.
Stockout — Pin inventory's central failure to a precise binary event — on-hand stock for one SKU at one location reaching zero while demand still arrives — whose heterogeneous, mostly-unobservable cost, weighed against holding cost, drives every safety-stock and service-level decision.
Transshipment — Move cargo through intermediate transfer points where it changes vehicle or mode, and re-price the journey as a fixed handling charge per transfer plus linear haul cost — so total cost keys to the number of transfers, not the distance travelled.
Vendor-Managed Inventory — Shift four coupled properties — consumption data, replenishment authority, stock ownership, and risk — upstream from buyer to supplier as a single bundle, dampening the bullwhip effect at the cost of a principal-agent gap that governance metrics must close.
Warehouse Slotting Failure — Diagnose a chronically slow but findable warehouse as a layout misaligned with demand flow — fast SKUs stranded in high-access-cost positions — by checking whether the position-cost ordering and the SKU-velocity ordering have drifted apart.
Wave Picking — Release warehouse orders not on arrival but in timed, compatibility-grouped cohorts, deliberately accepting a bounded latency wait so that picking, packing, and loading run synchronously against the same wave and downstream stations stay neither starved nor overwhelmed.