OPS.8.1:11 - SoTA-Echoing

For the question “may this new job start while earlier work can return?”, the selected line combines a defined release signal with the remaining resource demand and the required service. Two simpler alternatives are one-in/one-out counting and waiting for final acceptance. The first can omit consequential load; the second can delay work without protecting that service. Sections 4.1–4.5 add the event, load, timing and feedback operations needed to decide between them. Cases 5.1–5.3 demonstrate different outcomes, including a condition under which holding capacity cannot help.

Hopp and Spearman, Factory Physics, third edition, §10.4 and §§14.3.1–14.3.2, supply CONWIP’s controlled-loop construction and the distinction between counting jobs and accounting for unequal resource demands. Adopt the loop boundary and adapt the treatment of work diverted for rework: freeing a card requires retaining whichever other admission and load rules govern that work. No universal final-customer-acceptance boundary is inferred.

Steve Tendon, The Book of TameFlow (2022), printed pp. 117 and 138, supplies a concrete contrast: a constrained team’s completion triggers replenishment, while the teaching exercise also permits a customer return for reprocessing and retains elapsed project time. Adopt the separate signal and customer-clock operations. Adapt the release choice to the actual return resource and timing through sections 4.2–4.5; the exercise does not establish that every operation can absorb any later correction.

Thürer and Stevenson, Workload Control in Job Shops with Re-entrant Flows: An Assessment by Simulation, §§3.2 and 4.3–4.4, compare load accounting and release behavior for known repeated visits. Their corrected load weights route positions, and a starvation-triggered exception can exceed a norm. Adopt explicit repeated-visit accounting; distinguish that congestion policy from the finite occupied-hours test in 4.3. The study does not supply the timing or distribution of an as-yet-undiscovered correction.

Prabhu and colleagues (2024), the REM subsection on printed p. 149 and comparison on pp. 152–153, combine regular and re-entrant workload in a release rule. Adapt that combined-load comparison in 4.2–4.3: possible corrections still awaiting discovery need an allowance or scenario in addition to known visits, and resource-specific time limits remain. The study’s rankings differ for flow time, throughput and modeled profit, supporting the receiving-question comparison in 4.4. Its rotor-blade simulation does not select a universally best rule. The occupied-hours screen here is an accounting bound followed by placement, rather than a protection claim inferred from an average population-time relation.

Reopen the selection when another signal or accounting method supports the same receiving result with less delay, information or coordination, or when returns, resource sharing, interruption, feedback timing or service requirements change. Compare outcomes at the original customer boundary; changing that boundary is not evidence that the rule improved service.