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Chapter 06 of 14 · Part II · Draft web edition

Time, identity and state turn sensor readings into industrial evidence

A value becomes useful evidence only when the factory can establish what it describes, when it happened and which state or transformation it represents.

Sections
7
Exhibits
5
Minutes
28
Sources
18
EX 25 · 60: Retry follows hour cut. Duplicate delivery of A is detected; provisional bucket remains provisional.

The cloth is woven from this chapter's 5 exhibits: each weft is one exhibit's own data, normalised; each warp group is a section. The probe reads the exhibit's own value where it crosses. Procedural visualisation, not a measurement.

The chapter as a draft: 7 sections, 4 exhibit wefts, one shuttle.

Lead exhibit · 25TimelineillustrativeLate arrival changes processing order without changing event time
3A occurs and arrives17B occurs and arrives42C occurs into buffer60Retry follows hour cut65D occurs and arrives67C arrives andrecomputes

Read-out3: A occurs and arrives. Event minute 3; ingestion minute 3.

Method and source

Six illustrative timeline entries for events A, B, C and D, one transport retry and one KPI recomputation. All times are invented to demonstrate the method. Dual-time semantics derive from S08 and S0601, and buffering from S33. The exhibit does not set a recommended lateness threshold.

Unit: minutes after 09:00 (illustrative). Status: illustrative. Sources: S08, S33, S0601. Illustrative figures are teaching examples, not measured factory results.

The chapter's warpBar: share of the reading · square: an exhibit

Section 6.0 · Opening · 1 min · no exhibit of its own · one movement Go to section ↓

The chapter cloth8 warp groups · one pick per paragraph

This paragraph previews 6.1 · Event time and ingestion time answer different questions

A sensor reading becomes industrial evidence only when it is bound to an event time, a stable operational identity and an explicit state or transformation. A counter value alone cannot establish whether output occurred, which asset or lot produced it, whether the line was running, or whether a later replay has already counted it. The chapter's answer is therefore a governed evidence chain: keep event time separate from ingestion time, resolve events against versioned master data, represent genealogy and state transitions explicitly, make replay idempotent, append corrections, and retain each record class for a stated purpose.[S05][S08][S09] The sensor value remains an observation. Evidence is the reconstructable account of what that observation meant when a person, KPI or model used it.

This distinction lets a factory migrate from manual hourly logs to machine ingestion without rewriting its operating history. In Cameroon, where GFT's programme evidence base prepared on 31 January 2024 records about 95 percent of cotton fibre exported raw and about 5 percent processed locally against a 50 percent target by 2030 (with original source dates unrecorded and not refreshed in 2026), expanding domestic processing depends on operational records that hold up across shifts, power interruptions and buyer audits.[R06][R07] Preserving time, identity and state prevents a delayed connection from masquerading as a production stop, a renamed asset from losing its past, a split lot from acquiring a fictitious single batch identity, and a retried message from becoming additional output.[S08][S33][S38] It also gives later forecasting and inspection models the same temporal and operational definitions used on the floor, rather than allowing each training pipeline to invent them again.[S04][S15]

6.13 min · 3 sub-steps · 1 exhibit

Event time and ingestion time answer different questions

Related · chapter 049 paragraphs step it

Related exhibit 16 · chapter 04FlowderivedQuarantine keeps bad records visible without contaminating curated data
Capture raw eventCheck entry syntaxValidate contractPublish curated recordIsolate in quarantineSteward correctionLog provenance and reprocess

Read-outCapture raw event. Starting point. Leads to Check entry syntax.

Method and source

Derived operational control flow linking raw capture, entry syntax check, ingestion contract gate, quarantine isolation, steward remediation and provenance-logged reprocessing, based on ISO 8000-1 (S01), ISO/IEC 5259-3 (S04) and W3C PROV-O (S09).

Unit: . Status: derived. Sources: S01, S04, S09.

Read this exhibit in its chapter ↗
6.1 · Introduction · paragraph 1 of 9

Every governed event needs two timestamps. Event time records when the represented operational occurrence happened. Ingestion time records when the receiving system accepted its record. EPCIS makes the equivalent distinction explicit: its recordTime is a bookkeeping mechanism and does not describe the real-world event.[S0601] A factory should also distinguish processing time, when a particular transformation ran, from both. A stoppage that occurred during one shift but arrived during the next belongs to the first shift's operating account and to the second shift's data-latency account. Those are different questions, and neither timestamp can answer both.[S08][S33]

6.2 Two clocks protect the production account from the network account

The raw record should preserve the source's event timestamp, its stated time-zone offset and the receiving system's ingestion timestamp without overwriting either. Normalising an additional representation to Coordinated Universal Time makes cross-system ordering consistent, but the original local representation remains useful evidence about what the source asserted.[S08] Ingestion time supports freshness monitoring, replay diagnosis and reconstruction of what a dashboard could have known at a given moment. Event time supports output windows, state intervals, genealogy and features that must not use future information.[S15][S38]

This separation changes operational behaviour. When a gateway reconnects, the custodian investigates the interval between event and ingestion timestamps as a continuity issue. The production steward does not automatically treat that interval as missing output or unplanned downtime. Conversely, a feed can arrive promptly with a wrong event timestamp because a device clock has drifted. Low ingestion latency therefore proves delivery speed, not temporal accuracy.[S0601][S33]

6.3 Clock source and uncertainty make a timestamp inspectable

GFT's event contract adds clock source, observed clock offset or uncertainty, and a source sequence number where the device provides one. These fields are engineering metadata, not decorative compliance. A line-side terminal, programmable controller and manual back-entry form can assert different degrees of temporal confidence even when their displayed timestamps have the same precision. Recording the source and an estimated uncertainty lets a steward decide whether two events can be ordered safely or need review.[S08][S09]

The estimate needs a method. At commissioning and after a gateway restart, the custodian can compare the device with the site's chosen time reference, record the observed offset and retain the check date. Any uncertainty attached to a record should be labelled an estimate based on that check, not presented as a measured guarantee for every later event. Where the uncertainty crosses an hourly or shift boundary, the record should carry a boundary-review flag rather than a falsely precise allocation. A source sequence can help diagnose order within one device, but it cannot establish order across independent devices and cannot replace event time.[S05][S0601]

Manual entries require the same honesty. If a supervisor records a stoppage after the event, the form should ask when it happened and separately capture when the entry was submitted. It should not silently replace the first with the second. Back-entry status and the submitting role become provenance, while any unnecessary worker identity remains outside the production feed.[S09][S29]

6.4 Aggregation windows need an explicit lateness rule

An hourly bucket is a governed calculation, not a natural property of incoming messages. The KPI contract must state its event-time window, inclusion rule, provisional period, late-event treatment and formula version, consistent with ISO 22400's emphasis on formula, elements, time behaviour and unit.[S38] A live operational view may publish a provisional total so the shift can act, then issue a new calculation version when an accepted late event arrives. A monthly report may use a longer closure period. Neither waiting period is a universal constant; each is a site decision based on decision urgency and observed delay.

The same rule must reach model datasets. If a training feature describes an hour, its manifest should show whether late events were included up to a defined ingestion cut-off and which recalculation version produced the value. Otherwise a model can learn from a more complete history than will exist when it makes a live prediction.[S04][S15] Exhibit 25 isolates the temporal mechanism before the worked example adds quantities.

The important result in Exhibit 25 is not the arrival order. It is the preservation of two valid histories: what happened in production, and what the information system knew at each point. C does not move to D's hour merely because it arrived after reconnection, and the retry of A does not create a new production event. The exhibit cannot tell a factory how long to keep a bucket provisional, nor can it prove that the source clocks were correct. Those require site rules and clock evidence.[S0601]

6.52 min · 2 sub-steps · 1 exhibit

Master data stabilise the factory's objects

An event identifier says which record is being described. A master identifier says which persistent object the record concerns. The second remains stable while names, locations, assignments and other attributes change. IEC 62264 supplies role-based equipment and physical-asset hierarchies, while OPC UA provides an information-modelling framework for objects and their relationships; neither removes the factory's duty to decide which record is authoritative.[S05][S06] GFT therefore separates the slow-changing master record from the high-frequency event stream and gives every master class an identified origin, steward and effective history.

6.6 Identity persists while attributes receive effective dates

6.6

A sewing asset can keep one immutable asset identity when its display name changes, when it moves to another line, or when its controller is replaced. Those are three different changes. Renaming alters an attribute. Moving alters a role-based assignment with a start and end time. Replacing the controller may alter a technical relationship without replacing the production asset, provided the asset owner confirms that operational continuity remains valid.[S05][S06] The event never carries a mutable display name as its only link to the object.

¶ 02 · 2 sources

S05S06

Each derivation then resolves the master version effective at event time, not whichever version happens to be current when a query runs. A historical output total remains assigned to the line on which the asset operated at that time. A current capacity view uses the current assignment. Both views can coexist because they state their temporal rule. The curated record should retain the master-data version or effective-dating evidence used in the join, so a later hierarchy edit cannot silently redistribute history.[S05][S09]

¶ 03 · 2 sources

S05S09

6.7 Registry authority prevents one object becoming several identities

6.7

Master data also need a merge and retirement rule. If two registers contain the same physical asset, the steward does not delete one and leave dangling events. The registry records a mapping from the superseded identifier to the surviving identifier, the approval, the effective time and the reason. Existing raw events retain their original identifier; curated products apply the governed mapping and preserve that transformation in lineage.[S02][S09] An identifier that has been retired must not be issued to a different object, because reuse would make old events indistinguishable from new ones.

¶ 04 · 2 sources

S02S09

Exhibit 26 turns these rules into a compact registry design. Its entries are illustrative classes and controls, not a claim that a particular factory already operates this registry.

Exhibit 26RegisterillustrativeAn identity registry records origin, authority and permitted reuse
Entity class
Asset
Authoritative origin
Engineering asset register
Identity and effective history
Immutable asset ID; dated line and controller links
Permitted reuse
Events, maintenance and resource allocation

Read-outEntity class: Asset. Authoritative origin: Engineering asset register. Identity and effective history: Immutable asset ID; dated line and controller links. Permitted reuse: Events, maintenance and resource allocation

Open the full register (7 rows)
AssetEngineering asset registerImmutable asset ID; dated line and controller linksEvents, maintenance and resource allocation
OrderOrder-management recordOrder ID with versioned style, quantity and due attributesScheduling, output and delivery reconciliation
LotMaterial receipt or transformation eventLot ID plus parent and child event linksGenealogy, quality and provenance
StyleProduct-definition registerStyle ID with dated operation and unit versionsRouting, costing and feature derivation
OperationVersioned routing definitionOperation ID effective within a style versionWork-centre events and cycle-time analysis
Defect codeQuality taxonomy ownerStable code with dated label and mapping historyInspection, rework and model labels
Worker roleAuthorised role registerRole ID only; no person ID in production eventsAuthority checks and shift-level aggregation
Method and source

Illustrative master-identity registry based on equipment and enterprise boundaries in S05, object and relationship modelling in S06, and personal-data minimisation in S29. Rows are recommended design examples, not observed implementations or GFT operating results.

Unit: illustrative registry design. Status: illustrative. Sources: S05, S06, S29. Illustrative figures are teaching examples, not measured factory results.

The registry in Exhibit 26 deliberately gives worker role a different treatment from machine and material identities. A production event may need to show which role was authorised to declare a transition, without attaching a persistent person identifier to every output record.[S29] The table also shows why master data cannot be reduced to a list of codes: each class has an origin, an effective history and a permitted use. What it does not supply is the site-specific code format, which should follow existing operating needs rather than an imposed naming convention.

¶ 01 · 1 sourceExhibit 26

S29

6.82 min · 1 sub-steps · 1 exhibit

Genealogy links inputs, transformations and outputs

Genealogy is a chain of event relationships, not a batch field copied from one database row to the next. EPCIS is designed to share visibility event data about objects in a business context, while PROV-O represents entities, the activities that transform them and the agents responsible.[S08][S09] Together they support a practical factory model: receipt creates an identified input lot, splitting relates children to their parent, joining records all inputs to a new output, and rework creates a traceable transformation rather than silently changing the original lot's status.

6.9 Parent and child links survive split, join and rework

6.9

A single batch_id on a garment order fails as soon as production has more than one input or output. If a cotton lot is split, each child needs its own identity and a link to the parent. If yarn from two lots enters one fabric batch, the output needs links to both. The graph must be many-to-many, with the transformation event carrying the event time, location, operation and responsible role needed to interpret the relationship.[S08][S09] Copying only the most recent lot identifier would discard the earlier inputs and make provenance dependent on memory.

¶ 02 · 2 sources

S08S09

Rework needs equal care. The original inspection event and rejected state remain evidence. A rework event identifies the affected object, operation and outcome; a subsequent inspection creates a new disposition. If the physical item retains its identity, the events carry its changing state. If the process creates a new roll, lot or bundle, the new identifier receives a derivation link. The choice follows physical practice, not database convenience.[S08][S09]

¶ 03 · 2 sources

S08S09

Exhibit 27 shows the minimum relationship pattern. It is a derived event design, not a mass balance and not an observed production history.

Exhibit 27FlowderivedEvent genealogy preserves lot history through split and rework
Receive cottonlot LSplit L into Aand BTransform Ainto yarn YATransform Binto yarn YBJoin YA and YBinto fabric FInspect roll Rfrom FRework R intoroll R2Dispatch orderO from R2

Read-outReceive cotton lot L. Starting point. Leads to Split L into A and B.

Method and source

Derived genealogy pattern using visibility events from S08 and entity, activity and derivation relationships from S09. Identifiers are illustrative and links carry no quantities. The diagram does not demonstrate material conservation, legal chain of custody or carbon allocation.

Unit: event and entity relationships. Status: derived. Sources: S08, S09.

The flow in Exhibit 27 preserves why illustrative order O has a more complicated ancestry than one lot code can express. It also separates an inspection observation from the transformation that followed it. The links must carry quantities in the actual event records where allocation requires them, but the diagram deliberately makes no conservation claim. WP05 owns provenance and chain-of-custody method; WP16 owns carbon allocation. This chapter supplies the temporal and identity evidence those methods need, not their accounting conclusions.[S08][S09]

¶ 01 · 2 sourcesExhibit 27

S08S09

Note · 2 sources

S08S09

6.103 min · 2 sub-steps · 1 exhibit

Explicit states prevent incompatible downtime and defect counts

Step 1 of 7Time: running

Exhibit 28 · illustrativeA governed state machine stops one interval becoming two losses

Time: runningTime: planned stopTime: unplanned faultTime: blockedTime: starvedUnit: firstinspectionUnit: reworkUnit: accepted orscrapped
Time: runningTime:planned…Time:unplann…Time:blockedTime:starvedUnit: firstinspectionUnit:reworkUnit: accepted or scrapped

Time: running

Time: running. From Time: planned stop (Authorised restart), Time: unplanned fault (Repair verified), Time: blocked (Downstream released), Time: starved (Input available). Leads to Time: planned stop (Authorised stop), Time: unplanned fault, Time: blocked, Time: starved. · illustrative

A state is a governed interpretation of an entity during an interval or after an event, not a free-text label on a dashboard.

Time: planned stop

Time: planned stop. From Time: running (Authorised stop). Leads to Time: running (Authorised restart). · illustrative

Time: unplanned fault

Time: unplanned fault. From Time: running. Leads to Time: running (Repair verified). · illustrative

Time: starved

Time: starved. From Time: running. Leads to Time: running (Input available). · illustrative

Unit: first inspection

Unit: first inspection. Starting point. Leads to Unit: accepted or scrapped (Accept or scrap directly), Unit: rework (Repairable defect). · illustrative

Unit: rework

Unit: rework. From Unit: first inspection (Repairable defect). Leads to Unit: accepted or scrapped (Reinspection decides). · illustrative

Unit: accepted or scrapped

Unit: accepted or scrapped. From Unit: first inspection (Accept or scrap directly), Unit: rework (Reinspection decides). End point. · illustrative

Method and source · Exhibit 28

Illustrative asset-time and unit-disposition state machines. Transition design and the requirement to state KPI time elements derive from S38. Reason codes, transition authority and acceptance thresholds remain site decisions. The two tracks must not be added as if they had a common denominator.

Unit: illustrative state transitions. Status: illustrative. Sources: S38. Illustrative figures are teaching examples, not measured factory results.

6.10 · the bodyExhibit 28 above; its figures are illustrative where marked.

A state is a governed interpretation of an entity during an interval or after an event, not a free-text label on a dashboard. Machine-time states and unit-disposition states answer different questions. A sewing line can be running while a garment is in rework, and a line can be stopped while an operator inspects a unit. Treating rework as a machine state or blocked as a defect disposition mixes those dimensions and makes downtime and defect totals irreconcilable.[S38] GFT therefore keeps separate state machines for asset time and material disposition, linked by events but never added together as if they shared a denominator.

6.11 State contracts define entry, exit and transition authority

6.11

Each state definition needs an entity class, meaning, entry condition, exit condition, permitted reason codes, overlaps and authoritative role. The event that changes state records the previous and next values, event time, ingestion time, source and transitioning role. A supervisor may authorise a planned-stop classification, a maintenance role may verify restart after a fault, and a quality role may authorise rework or scrap. The small-team role assignments remain explicit rather than being buried in software permissions.[S02][S09]

¶ 02 · 2 sources

S02S09

Allowed overlaps must be equally precise. Under an exclusive asset-time model, one asset cannot be running and in an unplanned fault during the same interval. It can, however, be in an unplanned fault while an order is awaiting material and a unit is held for inspection, because those states belong to different entities and dimensions. Where management wants simultaneous technical and business states, the contract should publish separate fields rather than force both into one status column.[S38]

¶ 03 · 1 source

S38

Late and back-entered transitions follow the same temporal rule. If a fault began before it was entered, its interval begins at the evidenced event time and its ingestion record shows the delay. A missing end transition leaves an open interval flagged for steward action, not an automatic zero-duration stop. If a later correction changes the start or end, the original transition remains available through the append-only correction mechanism described below.[S0601][S0602]

¶ 04 · 2 sources

S0601S0602

6.12 KPI mappings consume each interval and unit once

6.12

For each asset-time model, the base states should form a complete and non-overlapping partition of the time being measured. Reason codes add diagnosis without creating a second duration. A fault interval carries one fault reason; it does not also create a generic downtime interval that is added to the fault duration. Planned stop, blocked and starved intervals enter availability or other KPI calculations only through the exclusions and time elements in the active KPI version.[S38] The mapping is part of the definition, not an analyst's later preference.

¶ 05 · 1 source

S38

Unit disposition follows a separate event path. First-pass acceptance, rework, reinspection and scrap describe the fate of a unit or lot. Defect counts need a stated unit and inspection boundary, just as downtime needs a stated asset and time boundary. A second inspection after rework must not silently become another first-pass unit. These controls make the KPI numerator and denominator reconstructable rather than merely reproducible as code.[S04][S38]

¶ 06 · 2 sources

S04S38

Exhibit 28 places the two state machines side by side. It illustrates transition logic and does not prescribe one universal KPI formula.

The upper logic in Exhibit 28 allocates asset time once. The lower logic tracks material disposition without creating another downtime category. A blocked interval and a starved interval can carry different operational causes while receiving the same treatment in a particular availability formula, but that formula must be cited by version.[S38] The exhibit cannot determine whether a planned stop should be excluded at a given factory, nor can it establish that a source system's transitions are complete. Acceptance requires interval reconciliation against a known shift calendar and sampled physical observations.

¶ 08 · 1 sourceExhibit 28

S38

Key figures from chapter 01 · Exhibit 01Key figuressourcedLocal-processing ambition raises the cost of untrusted evidence
  • 95%Raw cotton fibre exportedApproximate inherited sector baseline (R06; original date unrecorded)
  • 5%Cotton fibre processed locallyApproximate inherited sector baseline (R06; original date unrecorded)
  • 50%National processing targetSND30 local-processing target by 2030 (R07; policy target, not realised output)

Read-outRaw cotton fibre exported: 95%. Approximate inherited sector baseline (R06; original date unrecorded)

Method and source

Inherited GFT programme evidence base prepared 31 January 2024. R06 and R07 were not refreshed in 2026 and their original publication dates are unrecorded. Figures describe sector-level baseline and policy ambition, not a current GFT factory measurement or causal productivity claim.

Unit: percent of cotton fibre. Status: sourced. Sources: R06, R07.

Read this exhibit in its chapter ↗

6.134 min · 2 sub-steps · 1 exhibit

Replay must not create a second reality

Step 1 of 5Naive message sum at 10:00

Exhibit 29 · illustrativeDeduplication and event-time allocation reconcile the 09:00 bucket

020406060Naive messagesum at 10:00−20Removeduplicate ret…40Provisional09:00 bucket+20Allocate latebuffered C60Recalculated09:00 bucket0204060Naive message…60Remove…−20Provisional…40Allocate late…+20Recalculated…60

Naive message sum at 10:00

Naive message sum at 10:00: total 60. Running total 60 illustrative pieces in 09:00 bucket · illustrative

Buffered delivery and transport retries protect availability, but they also create a governance risk: the same application event can arrive more than once or after later events.

Remove duplicate retry A

Remove duplicate retry A: removes 20. Running total 40 illustrative pieces in 09:00 bucket · illustrative

Provisional 09:00 bucket

Provisional 09:00 bucket: total 40. Running total 40 illustrative pieces in 09:00 bucket · illustrative

Allocate late buffered C

Allocate late buffered C: adds 20. Running total 60 illustrative pieces in 09:00 bucket · illustrative

Recalculated 09:00 bucket

Recalculated 09:00 bucket: total 60. Running total 60 illustrative pieces in 09:00 bucket · illustrative

The method behind it: Method.

Method and source · Exhibit 29

Illustrative reconciliation from the worked example: 3 arrived messages x 20 pieces = 60 naive pieces at the 10:00 cut, less 20 pieces for the duplicate retry of A (giving 40 provisional pieces), plus 20 pieces when buffered event C arrives at 10:07 and is allocated to its 09:42 event time (giving 60 recalculated pieces). Values are invented for method demonstration, not GFT operating results.

Unit: illustrative pieces in 09:00 bucket. Status: illustrative. Sources: S07, S33, S38, S0601, S0603. Illustrative figures are teaching examples, not measured factory results.

6.13 · the bodyExhibit 29 above; its figures are illustrative where marked.

Buffered delivery and transport retries protect availability, but they also create a governance risk: the same application event can arrive more than once or after later events. MQTT supplies publish-subscribe transport, not a factory-specific rule for recognising production identity.[S07] The capture boundary must therefore issue a stable event identifier that survives every retry and buffer cycle, such as a time-ordered RFC 9562 UUIDv7 value generated when the occurrence is recorded.[S0603] A repeated transmission keeps that identifier; a genuinely new occurrence receives a new one even if its value, asset and timestamp happen to match another record.[S08][S33]

¶ 01 · 4 sources

such as a time-ordered RFC 9562 UUIDv7 value generated when the occurrence is recordedS0603

Related · Exhibit 22 · chapter 05

S07S0603S08S33

6.14 Stable event identifiers make consumers idempotent

6.14

Idempotency means that processing the same event again produces no additional unintended effect. The raw store accepts one identity once, and every derived consumer either tracks the event identifiers already applied or recomputes from a defined input set rather than blindly incrementing a total. A dataset manifest records the included identifiers and rule versions so a training snapshot can be rebuilt without double counting.[S04][S15] Deduplication is therefore a chain-wide obligation, not only a broker setting.

¶ 02 · 2 sources

S04S15

A conflict needs a different response from a duplicate. If two messages carry the same event identifier and the same canonical payload hash, the consumer can recognise a retry. If they carry the same identifier but different hashes, it must quarantine an identity conflict and preserve both payloads for investigation. Choosing the latest would allow a transmission fault or unauthorised change to rewrite evidence without explanation.[S04][S09]

¶ 03 · 2 sources

S04S09

6.15 Deterministic replay rebuilds products rather than rewriting them

6.15

A controlled replay reads the preserved raw set, applies a named schema, master-data, state and KPI version, then publishes a new derived version with lineage to the execution. It does not mutate an old product in place and pretend that consumers saw the same result all along.[S09][S15] Where the same inputs and rules produce a different output, the team has found nondeterminism or an unrecorded dependency. That defect should block acceptance until explained.

¶ 04 · 2 sources

S09S15

These tests should run before a feed enters operational or training products and whenever its contract changes. They use synthetic events with known outcomes, so no production order or worker record is needed for the test.[S04][S29]

¶ 05 · 2 sources

S04S29

The worked example shows why replay acceptance must reconcile identities, event-time buckets and calculation versions together. Deduplication alone would still misallocate C. Event-time allocation alone would still count the retry. A versionless dashboard could calculate the correct final total while hiding the fact that its earlier figure had changed. Exhibit 29 summarises that reconciliation for the 09:00 hourly bucket across both adjustments. Operational monitoring should therefore retain provisional revision history, duplicate-conflict counts and lateness distributions alongside the published KPI.[S04][S38]

¶ 06 · 2 sourcesExhibit 29

S04S38

As Exhibit 29 makes visible, the naive message sum at 10:00 and the recalculated event-time bucket after 10:07 share the same illustrative value of 60 pieces, yet the first figure is wrong twice: it includes a duplicate retry of A and omits buffered event C.[S07][S33][S0601] Without identifier deduplication and dual-time accounting, those two errors mask each other in the 09:00 bucket while inflating the two-hour total to 100 illustrative pieces.[S38][S0603] What Exhibit 29 cannot establish is the site-specific outage distribution or the cut-off window for closing provisional shift reports, which must be set from measured plant connectivity.[S33]

¶ 07 · 5 sources

the naive message sum at 10:00 and the recalculated event-time bucket after 10:07 share…S07, S33, S0601 · illustrative

Exhibit 29

S07S33S0601S38S0603

6.162 min · 2 sub-steps · read with a related exhibit

Corrections append rather than erase

A correction changes the best supported account of an event; it must not destroy the earlier assertion or the fact that people acted on it. EPCIS error declarations follow this principle directly: the prior event is not modified, and subsequent queries return both the prior event and the declaration.[S0602] In W3C PROV-O, a revision is modelled explicitly as a derivation in which the resulting entity is a revised version of an original entity.[S0604] GFT applies the same pattern across manual and machine records. A superseding event identifies what it corrects, states the reason and changed fields, and records the submitting and approving roles with their declaration times. The original raw payload remains untouched.[S02][S09]

6.17 Correction time and effective time preserve two truths

6.17

A supervisor can discover today that yesterday's lot code was wrong. The corrected lot relationship takes effect for the current operational view, but the factory still needs to reconstruct yesterday's view when the original code was believed correct. Correction time records when the new assertion entered the system. Event time records the production occurrence being corrected. Keeping both prevents a present-day repair from pretending that past users possessed information they did not have.[S0601][S0602]

¶ 02 · 2 sources

S0601S0602

The curated model therefore supports two questions without confusing them. “What is our best current account?” follows the supersession chain to the effective record. “What did this report or model know at its execution?” uses the records and correction cut-off captured in its lineage. PROV-O derivation and revision relationships provide a standards-based way to represent those links, while the factory's own schema supplies reason, authority and approval detail.[S09][S15]

¶ 03 · 2 sources

S09S15

A correction can itself be wrong. The chain must allow a later superseding assertion with the same evidence requirements rather than editing the first correction. Current-state queries need a deterministic rule for selecting the effective tip of that chain, and any branching corrections require steward resolution. This avoids both destructive editing and an ambiguous collection of competing truths.

¶ 04

6.18 Recalculation is a new derived version, not silent historical drift

6.18

Every material correction triggers an impact assessment. The steward and custodian identify affected state intervals, genealogy paths, KPI windows, published products and dataset snapshots before releasing the new effective state. The pipeline then produces new calculation versions with links to the correction event and the exact rule versions used. A previously issued management report retains its original value and receives an addendum where the operating owner decides that restatement is required.[S02][S09][S38]

¶ 05 · 3 sources

S02S09S38

Frozen training data follow the same rule. The pipeline does not mutate an old snapshot and retain its identifier. It creates a new manifest that records corrected event identifiers, supersession links and the ingestion cut-off, then evaluates whether the change affects a candidate or deployed model.[S04][S15] This deliberate path distinguishes legitimate historical revision from silent drift and makes the operational consequence of a correction measurable.

¶ 06 · 2 sources

S04S15

6.192 min · 2 sub-steps · read with a related exhibit

Retention follows purpose and obligation

Retention is a decision about each record class, not a promise to keep everything forever or delete everything on one schedule. Raw evidence may be needed to reconstruct a customer inquiry or diagnose a recurring fault. Curated events need their schemas and master versions. Labels, snapshots and model artefacts need the lineage required to explain historical outputs. Access logs serve security investigation and have a different exposure and purpose.[S09][S15][S29] Each class therefore receives a purpose, owner, review trigger, deletion method and, where applicable, contractual or legal basis.

6.20 A differentiated schedule preserves evidence without indefinite accumulation

6.20

The retention register should address the classes separately:

¶ 02
  • Raw machine and material events: retain for the period justified by operational reconstruction, warranty, customer and applicable legal needs, with non-personal asset and lot identifiers preferred at capture.[S29]
  • Curated events and KPI results: retain the effective record together with the schema, master-data, state and calculation versions required to interpret it, rather than preserving a number whose definition has been lost.[S38]
  • Labels, dataset snapshots and model artefacts: retain for as long as historical predictions or releases require explanation, with the retention decision linked to consequence, contractual need and reusable validation value.[S15]
  • Access and correction logs: restrict them to their accountability and security purposes, because administrator and approver identifiers can themselves be personal data.[S29]
  • Worker-identifiable records: set the shortest justified period after the documented purpose and current Cameroonian legal review, using erasure or appropriately assessed anonymisation when that period ends.[S29][S31]
List · 4 sources

S29S38S15S31

These are decision fields, not proposed retention durations. A small factory should set actual periods only after reviewing operational reuse, customer terms, litigation or incident holds, and applicable law. Indefinite retention is not a conservative default when it increases privacy exposure and storage burden without a stated decision need.[S29]

¶ 03 · 1 source

S29

6.21 Deletion must reach copies without fabricating a new history

6.21

An executable retention procedure covers primary stores, replicas, local buffers, analytical exports and backup cycles. It records a minimal disposal receipt containing record class, scope, authority, execution time and verification result, not the deleted payload. Where immediate deletion from every backup is not feasible, the procedure isolates expired backups from ordinary use and ensures that a restoration cannot silently return deleted personal records to production. A legal or incident hold is scoped, approved and reviewed rather than becoming an invisible permanent exception.[S29][S31]

¶ 04 · 2 sources

S29S31

Aggregates require the same discipline. Removing direct identifiers does not automatically make a small-group or event-level dataset non-personal. The owner must obtain an appropriate assessment before treating an aggregate as exempt from the personal-data schedule. Where retention ends for raw operational evidence, derived records should not claim a lineage that can no longer be inspected; their metadata should state the disposal boundary honestly.[S09][S29]

¶ 05 · 2 sources

S09S29

Note · 1 source

S31

Time, identity and state turn readings into evidence because they make every later use answerable to its original context. Replay, correction and retention then preserve that answerability as systems change. The factory can reconstruct not only a value, but also the object, occurrence, transformation, rule and knowledge state behind it.

¶ 06

Check the record

The chapter keeps its sources within reach.

Every knot is a source this chapter cites; select one to read its record, or filter the register by grade. Publication dates and inherited-source limits stay explicit. Read the paper's full evidence summary.

18 sources · 130 citation marks on this pageMost cited: S09, 19 times

Grade AGrade BGrade CKnot size: citations on this page

All 18 records shown

R06 · Grade C · inherited record

Cameroon Trade Hub

Inherited evidence R06

About 95 percent of cotton fibre exported raw against 5 percent processed locally; industrialisation target of 50 percent local processing.

Publication date unrecorded. Inherited source-text record. The original publication has not been independently reopened for this web edition.

Chapter source notes

S05 International Electrotechnical Commission. 2013.

S08 GS1 AISBL. 2022.

S09 World Wide Web Consortium. 2013-04-30.

R06 Cameroon Trade Hub. Publication date unrecorded; inherited source-text check.

R07 Ecofin Agency. Publication date unrecorded; inherited source-text check.

S33 Microsoft. 2024-06-10.

S38 International Organization for Standardization. 2014.

S04 ISO/IEC. 2024.

S15 Google Cloud. 2024-08-28.

S0601 GS1 AISBL. 2022.

S29 European Parliament and Council of the European Union. 2016-04-27.

S06 OPC Foundation. 2025-10-22.

S02 International Organization for Standardization. 2022.

S0602 GS1 AISBL. 2022.

S07 OASIS Open. 2019-03-07.

S0603 Internet Engineering Task Force. 2024-05.

S0604 World Wide Web Consortium. 2013-04-30.

S31 Presidency of the Republic of Cameroon. 2024-12-23.

Keep the thread · chapter 06 of 14

Chapter 07 picks up the thread.

Move the shuttle along the rack to preview any chapter: its sections, exhibits and reading time. Draft web edition. This research is not investment, legal or tax advice; illustrative models are not measured factory results.

The paper's rack · 14 boltsBolt length: reading time

07Part II: Build the minimum durable spine

Security and privacy are design constraints, not aftercare

The data spine must protect production, people and legitimate access at the same time, with controls proportionate to a small team.

  • 7.1OT consequences set the control objective
  • 7.3Least privilege covers people and machine identities
  • 7.5A small-team baseline prioritises essential cyber hygiene
  • 7.6Recovery evidence matters more than backup completion
Reading time
28 min
Exhibits
4
Sections
8
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