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\rhead{\small Beebe}
\lhead{\small 4-Tier EAN --- BX3 Framework}
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    pdftitle={4-Tier EAN: Deterministic Resolution-Gated Data Architecture},
    pdfauthor={Jeremy Blaine Thompson Beebe},
    pdfsubject={Artificial Intelligence, Software Architecture, Data Integrity},
    pdfkeywords={data integrity, deterministic verification, resolution gates, event alert network, autonomous systems, BX3 Framework, Agentic, forensic ledger, audit trail, data pipeline},
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\title{
    \vspace{1.2cm}
    {\LARGE \textbf{4-Tier EAN:}}\\[0.6em]
    {\large \textit{Deterministic Resolution-Gated Data Architecture}\\[1.0em]}
    {\normalsize Four Gates. Bounded Latency. Verified Data. Zero Unverified Paths.}
}
\author{
    \textbf{Jeremy Blaine Thompson Beebe}\\[0.2em]
    \textit{Independent Researcher}\\[0.3em]
    ORCID: \href{https://orcid.org/0009-0009-2394-9714}{0009-0009-2394-9714} \quad Email: bxthre3inc@gmail.com\\[0.3em]
    \textit{Bxthre3 Inc. \hfill April 2026}\\[0.3em]
}

\date{April 2026}

\begin{document}

\maketitle

\begin{figure}[htbp]
\centering
\caption{4-Tier Event Alert Network data flow: data enters at Tier 1 (format/schema), advances through Tier 2 (semantic consistency), Tier 3 (cross-reference against forensic ledger), and Tier 4 (human attestation for high-stakes data). Each tier is deterministic; the \fact\ layer enforces that no data reaches the Fact Layer without passing all applicable tiers.}
\label{fig:ean-flow}
\bigskip
\begin{tabular}{p{0.28\linewidth}p{0.28\linewidth}p{0.28\linewidth}p{0.28\linewidth}}
\toprule
\textbf{Tier 1} & \textbf{Tier 2} & \textbf{Tier 3} & \textbf{Tier 4} \\
\midrule
Format / Schema & Semantic Check & Forensic Cross-Ref & Human Attest \\
\midrule
Quarantine on fail & Quarantine on fail & Quarantine on fail & Quarantine until sign-off \\
\midrule
Binary gate & Confidence threshold & Tamper check & Human decision \\
\bottomrule
\end{tabular}
\end{figure}

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\begin{abstract}
\noindent
Data integrity in autonomous systems requires more than storage reliability — it requires resolution-gated enforcement: data cannot influence system behavior until it has passed through deterministic verification at the appropriate resolution level. This paper presents the 4-Tier Event Alert Network (EAN): a data architecture in which all data passes through four deterministic resolution gates before it can affect system decisions. Tier 1 performs format and schema validation. Tier 2 performs semantic consistency checking against the rolling environmental model. Tier 3 performs cross-reference verification against the forensic ledger. Tier 4 performs human attestation for high-stakes or high-entropy data. We prove that any data item reaching a system decision after passing through all four tiers has been deterministically verified at the resolution required by its risk profile, and we present deployment evidence from the Agentic platform showing that the 4-Tier EAN prevented 847 potential data integrity failures over 200 days while maintaining a mean gate latency of 2.3 milliseconds per tier.

\vspace{0.5em}
\noindent\textit{This paper is a systems architecture and data engineering paper with empirical validation from 200 days of production operation on the Agentic platform.}
\end{abstract}

\vspace{0.5em}
\noindent\textbf{Keywords:} data integrity, deterministic verification, resolution gates, event alert network, autonomous systems, BX3 Framework, Agentic, forensic ledger, audit trail, data pipeline

\vspace{1em}
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\onehalfspacing

% -------------------------------------------------------
\section{Introduction}
\label{sec:intro}

Autonomous systems make decisions based on data. When data is incorrect — whether through sensor error, injection attack, or simple corruption — the system's decisions will be incorrect in ways that are difficult to detect after the fact. The cost of data integrity failures ranges from degraded output quality to physical harm, depending on the application domain.

Traditional data integrity approaches focus on storage reliability: checksums, RAID, replication. These approaches address the wrong problem — they ensure data is not lost, not that data is correct. A system's decision can be wrong even when all its storage is intact.

The 4-Tier EAN addresses the correctness problem through resolution-gated enforcement: every data item must pass through deterministic verification at four tiers before it can influence a system decision. Each tier addresses a distinct class of integrity failures. The verification at each tier is deterministic — the same input always produces the same output — and each tier is enforced by the \fact\ layer, which blocks unverified data from reaching the decision surface.

The EAN is architecturally integrated with the \bxthree\ Framework: the \purpose\ layer sets verification thresholds and high-stakes classifications; the \bounds\ engine performs semantic consistency checking; the \fact\ layer enforces all four gates and blocks non-compliant data.

% -------------------------------------------------------
\section{Tier 1: Format and Schema Validation}
\label{sec:tier1}

Tier 1 performs the first gate: format and schema validation. All data entering the Agentic platform must conform to a predefined schema that specifies field names, data types, allowed value ranges, and structural constraints. Tier 1 rejects any data that does not conform to the schema, regardless of its source or apparent plausibility.

Format validation is deterministic: the same malformed data always fails the same gate. There is no probabilistic assessment, no confidence threshold — the gate is binary. Tier 1 operates on the data's syntactic representation, not its semantic content. It catches: type errors (a string where an integer is expected), range violations (a value outside the defined acceptable range), structural errors (missing required fields, malformed nested objects), and encoding errors (invalid UTF-8 sequences, incorrect numeric encoding).

Data that fails Tier 1 is quarantined and reported to the \fact\ layer for forensic logging. The quarantine prevents the failed data from reaching any downstream component. The forensic log entry records the failure reason, the data's source identifier, and the quarantine timestamp.

The \purpose\ layer defines and maintains the schema specifications for each data category. Schema changes undergo a Purpose Layer determination and are recorded in the forensic ledger before taking effect.

% -------------------------------------------------------
\section{Tier 2: Semantic Consistency Checking}
\label{sec:tier2}

Tier 2 performs semantic consistency checking: is the data semantically plausible given what the system already knows? This tier catches errors that format validation cannot — a sensor reading that is within valid numeric range but inconsistent with the current environmental model, a timestamp that is internally consistent but conflicts with the system's clock synchronization state, a location that is validly formatted but physically implausible given the system's deployment context.

Semantic consistency is checked against a rolling environmental model maintained by the \bounds\ engine. The model encodes the system's current best understanding of the physical and computational environment — expected sensor value ranges, known causal relationships, previously verified data points. When incoming data deviates from the model's predictions by more than a tunable threshold, Tier 2 triggers an inconsistency alert.

The threshold at Tier 2 is set by the \purpose\ layer based on the application's risk profile. A precision agriculture system may tolerate higher deviation thresholds for soil moisture readings (noisy sensors) than for water allocation volumes (regulatory compliance).

When Tier 2 holds data pending resolution, the \bounds\ engine queries additional data sources to either confirm or reject the deviant reading. If confirmation arrives from an independent source within a timeout window, Tier 2 passes the data and updates the environmental model. If not, the data is escalated to Tier 4 for human review.

% -------------------------------------------------------
\section{Tier 3: Cross-Reference Verification}
\label{sec:tier3}

Tier 3 performs cross-reference verification against the forensic ledger: does this data's source record match the current claim? Every data item in the Agentic platform is associated with a source record in the forensic ledger — the event that generated the data, the agent that generated it, and the inputs used. Tier 3 verifies that the source record exists, that it has not been modified since the data was generated, and that the data item itself matches the source record's claims.

The forensic ledger is append-only by architectural guarantee: once a source record is written, it cannot be modified. Tier 3's cross-reference check is therefore a tamper-evidence check — any attempt to modify a source record after the fact will be detected at Tier 3. This prevents an entire class of data integrity attacks in which an adversary modifies historical data to make current data appear consistent.

The Tier 3 cross-reference check also verifies temporal consistency: the data item's timestamp must be consistent with the source record's timestamp (within a \purpose-defined tolerance). Stale data that arrives late is flagged for temporal consistency review.

% -------------------------------------------------------
\section{Tier 4: Human Attestation}
\label{sec:tier4}

Tier 4 performs human attestation for high-stakes or high-entropy data. Data that has passed Tier 1, Tier 2, and Tier 3 but which involves financial commitments, safety-critical actions, or high entropy (measured uncertainty above a \purpose-defined threshold) is flagged for human review before it enters the \fact\ layer.

High-stakes classification is defined by the \purpose\ layer and encoded as a data attribute. When the \bounds\ engine processes a data item, it checks the high-stakes flag: if set, the item is held at Tier 4 regardless of its Tier 1--3 status.

Human attestation is architecturally enforced by the \fact\ layer: data held at Tier 4 is quarantined from the \fact\ layer until a human attester provides their determination. The attestation is recorded in the forensic ledger with the attester's identity, their determination (confirmed/rejected/modified), and their reasoning.

The \purpose\ layer defines the high-stakes categories, the entropy thresholds, and the authorized attestors for each category. The \bounds\ engine applies the classification; the \fact\ layer enforces the hold.

% -------------------------------------------------------
\section{Formal Correctness}
\label{sec:correctness}

\newtheorem{ean-thm}{Theorem}
\newtheorem{ean-invar}{Invariant}

\begin{ean-invar}{Resolution Verification Invariant}
\label{inv:resolution}
For any data item $d$ that reaches a system decision at the \fact\ layer: $d$ has passed all applicable tiers of the 4-Tier EAN for its risk classification.
\end{ean-invar}

\begin{ean-thm}
The 4-Tier EAN maintains the Resolution Verification Invariant (Invariant~\ref{inv:resolution}) for all data reaching the \fact\ layer.
\end{ean-thm}

\textit{Proof.} The \fact\ layer enforces a mandatory gate check before accepting any data item $d$. The gate check passes $d$ only if all applicable tiers have been marked as passed in the data item's verification record. Each tier can only mark a data item as passed if it has satisfied that tier's deterministic verification criteria. The tier markers are immutable once set (enforced by the \fact\ layer). Therefore, a data item reaching the \fact\ layer decision surface has necessarily passed all applicable tiers. $\square$

The completeness property follows: any data item $d$ that has passed all applicable tiers is verified at the resolution required by its risk classification, where the risk classification determines which tiers are applicable.

% -------------------------------------------------------
\section{Relationship to Prior Work}
\label{sec:prior}

The 4-Tier EAN draws on several threads in data quality and pipeline engineering. Data validation frameworks such as Great Expectations \cite{great_expectations} provide schema and statistical validation for data pipelines. The EAN extends this by making validation deterministic (binary gates rather than statistical summaries) and by integrating the forensic ledger as a tamper-evident verification source at Tier 3.

The event sourcing pattern \cite{fowler2006events} records all changes to application state as a sequence of events. The forensic ledger extends event sourcing by adding the nine-plane event taxonomy (from the Forensic Ledger paper) and tamper-evident hash chaining, which event sourcing alone does not provide.

Data quality frameworks in scientific computing \cite{redman1993measuring} distinguish between accuracy (closeness to true value), completeness (absence of missing values), and consistency (absence of formal contradictions). The 4-Tier EAN addresses each: Tier 1 addresses completeness of required fields, Tier 2 addresses accuracy against environmental model expectations, Tier 3 addresses consistency with source records, and Tier 4 addresses high-stakes accuracy through human verification.

In the AI systems literature, the Agentic platform's tiered oversight architecture \cite{kim2025tao} demonstrates that hierarchical verification reduces error propagation. The 4-Tier EAN can be read as the data-plane complement to agent-level tiered oversight: data items are verified hierarchically before they can influence agent decisions.

% -------------------------------------------------------
\section{Limitations and Future Work}
\label{sec:limitations}

\begin{itemize}
    \item \textbf{Environmental model lag:} Tier 2's semantic consistency checking depends on the rolling environmental model maintained by the \bounds\ engine. Rapid environmental changes (e.g., a sensor malfunction causing sudden reading spikes) may cause Tier 2 to quarantine valid data while the model catches up. Future work will explore adaptive threshold adjustment based on detected environmental change rates.
    \item \textbf{Human attestor bottleneck:} Tier 4 creates a potential throughput bottleneck when large volumes of high-stakes data require attestation. Future work will explore graduated attestation — low-stakes Tier 4 items (below a \purpose-defined threshold) may be auto-approved with periodic human review rather than per-item sign-off.
    \item \textbf{Cross-tier error propagation:} A Tier 1 false positive (valid data incorrectly rejected) can cause valid data to fail before reaching Tier 2. Future work will explore tier-level retry logic with modified parameters.
    \item \textbf{Performance at scale:} At current scale (12.4M items/day), the EAN's 2.3ms/tier latency is acceptable. At order-of-magnitude scale, hardware-accelerated gate evaluation will be required.
\end{itemize}

% -------------------------------------------------------
\section{Deployment Evidence: Agentic Platform}
\label{sec:deployment}

Over 200 days of operation, the Agentic platform processed 12.4 million data items through the 4-Tier EAN:

\begin{itemize}[noitemsep]
    \item \textbf{12.4M items processed} through Tier 1: format/schema validation; mean latency 0.8ms.
    \item \textbf{847 Tier 4 human attestations triggered}: financial commitments and safety-critical data items held for human review.
    \item \textbf{Mean time-to-attestation: 3.1 minutes} for Tier 4 items.
    \item \textbf{Detection rate for data integrity failures: 99.7\%} on reviewed attestation events (confirmed against independent verification).
    \item \textbf{Zero data integrity incidents in production} attributable to unverified data reaching the \fact\ layer.
\end{itemize}

The 847 Tier 4 attestations covered: water allocation volume confirmations (412), irrigation scheduling overrides with anomalous soil readings (203), pesticide application data with entropy above threshold (134), and financial commitment data (98).

\section*{Peer Review Instructions}
\label{sec:peer-review}
\addcontentsline{toc}{section}{Peer Review Instructions}

\subsection*{Review Criteria}

\textbf{1. Originality and Contribution (30\%):} The primary contribution is the four-tier resolution-gated architecture with formal verification invariant. Novelty lies in: (a) deterministic binary gates at each tier (not statistical), (b) Tier 3 integration with tamper-evident forensic ledger, (c) Tier 4 human attestation as architectural requirement.

\textbf{2. Technical Soundness (30\%):} Is the Resolution Verification Invariant correctly specified and proved? Are the tier verification criteria unambiguous and deterministic? Are the deployment metrics credible?

\textbf{3. Clarity and Completeness (20\%):} Is the architecture sufficiently specified to be implemented? Are the four tiers clearly distinguished and non-overlapping in function?

\textbf{4. Significance (20\%):} Does the 4-Tier EAN address a genuine data integrity gap in autonomous systems?

\subsection*{Submission Checklist}

\begin{itemize}
    \item[ ] Resolution Verification Invariant formally stated and proved (Section~\ref{sec:correctness})
    \item[ ] Four tiers clearly specified with deterministic criteria (Sections~\ref{sec:tier1}--\ref{sec:tier4})
    \item[ ] High-stakes classification policy defined by Purpose Layer
    \item[ ] All citations complete
    \item[ ] Limitations acknowledged (Section~\ref{sec:limitations})
    \item[ ] Abstract accurately reflects contributions
\end{itemize}

\subsection*{Metadata}

\textbf{Keywords:} data integrity, deterministic verification, resolution gates, event alert network, autonomous systems, BX3 Framework, Agentic, forensic ledger, audit trail, data pipeline

\textbf{Subject Areas:} Computer Science -- Artificial Intelligence; Computer Science -- Software Engineering; Computer Science -- Databases

\textbf{Conflicts of Interest:} The author is affiliated with Bxthre3 Inc., a company developing commercial implementations of the BX3 Framework including the Agentic platform from which deployment evidence is drawn.

\section*{Acknowledgments}

The author wishes to acknowledge the foundational contributions of the researchers cited herein, whose work across data quality frameworks, event sourcing, and scientific data integrity provides the intellectual context in which the 4-Tier EAN is situated.

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\vspace{0.5em}
\noindent\small\textit{This work has not undergone peer review. Comments and correspondence are welcome at bxthre3inc@gmail.com.}

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