arXiv subjects

Kentaro Oda

Publications and source records attributed to Kentaro Oda.

3 recordsLinked to original sources

arXiv2026

Attestream: Usage-Aware Intermittent Data Distribution with Verifiable Lifecycle Provenance for Machine-Learning Data Streams

Providers of continuously produced, commercially valuable data -- sensor streams, telemetry, and other feeds sold as machine-learning training material -- cannot observe whether delivered data is actually used, while data that keeps flowing to inactive consumers enlarges the leakage surface without producing value. We present Attestream, a blockchain-based architecture for intermittently delivered dataset streams that couples continued delivery to verifiable usage reporting. Every lifecycle event -- dataset preparation, dual-signed delivery, derivative creation (e.g., a model), and derivative distribution -- is appended to an on-chain registry as a non-repudiable, mutually linked lifecycle record. The mechanism requires provable transfer, not tokenization: plain contract storage, ERC-721 tokens, and anchored off-chain receipts are interchangeable representations of the same protocol. A usage-aware gate suspends a consumer's stream when no derivative-creation record is registered within a reporting window; evaluated lazily inside the next delivery transaction, monitoring adds no dedicated transactions. A modality-pluggable fingerprinting layer binds any leaked copy to the dual-signed delivery record of the responsible consumer, instantiated for tabular/geospatial records, images, and documents. We implement the registry as a Solidity contract with EIP-712 dual signatures and evaluate it: a full lifecycle round costs 657k gas with plain records ($0.13 on rollups; ERC-721 tokenization adds ~30k gas per record), and over a 50-consumer pool leak attribution reaches 100% from 40 leaked table rows under moderate noise, survives JPEG recompression to quality 30, and tolerates paraphrase rates up to 30% for documents.

cs.CR↗

arXiv2026

Separating Covariate Shift from Mechanism Change with Two Discriminators: CJSD, a Conditional Discrepancy with an Exact Covariate-Concept Decomposition

After the inputs X are known, how much additional information does the label Y carry about which dataset a sample came from? That single quantity -- estimable as the difference of two discriminators' held-out cross-entropies, D_CJS = CE(Z|X) - CE(Z|X,Y) -- is exactly the part of a dataset difference that covariate shift cannot explain. We propose the Conditional Jensen-Shannon Discrepancy (CJSD): with a task indicator Z, the chain rule I(Z;X,Y) = I(Z;X) + I(Z;Y|X) splits total task discrepancy exactly into a covariate axis and a functional axis, both estimable from two ordinary classifiers, with no task-specific predictors, generative models, or bootstrap surrogates. We prove a covariate-null property (the functional axis is exactly zero under pure covariate shift, however severe), a drift-mass law (D_CJS/ln2 equals the mass of the disagreement region for deterministic labels), a one-sided misspecification-control inequality (each direction of estimation error is bounded, unconditionally, by the excess risk of a single discriminator), and a fixed-measure metrization via an identifiability lemma. Empirically, on a ten-measure battery over 202 dataset pairs (synthetic, Electricity, Covertype), only the two conditional-information estimators -- CJSD and a kNN plug-in for the same estimand -- separate concept from covariate shift with AUC 1.0; the case for CJSD is the estimator: under controlled dimensionality scaling the kNN plug-in fails from d=64 while the discriminator route holds to d=256 with a swappable classifier, and it alone yields paired confidence intervals and sequential extensions from the same learned object. The same estimator audits the conditional fidelity of synthetic-data generators that marginal and joint QA metrics pass, detects annotation-guideline changes invisible to input-space monitors, and supports null-calibrated fairness audits.

cs.LG↗

arXiv2026

Evidence Before Expansion: Reuse, Spawn, or Defer in Lifelong Expert Pools

Streaming systems that maintain a pool of expert models must repeatedly decide whether to reuse an existing expert for arriving data, spawn a new one, or defer. We present a decision layer that makes all three outcomes statistically meaningful. Reuse and spawn are posed as one-sided sequential hypotheses on a conditional (mechanism-level) discrepancy, separated by an indifference zone; defer is exactly the state in which neither betting e-process has accumulated sufficient evidence. We prove finite-time anytime validity for the observable surrogate discrepancy of a predictable discriminator sequence, and an unconditional one-sided transfer to the population quantity in which each side's slack is the excess risk of a single discriminator; an empirically observed downward-bias regularity makes the spawn side exactly conservative. Recency without sacrificing the guarantee is obtained by a restarted e-detector: a bank of unwindowed betting supermartingales at geometrically spaced restart times (O(log t) memory), with the error budget spent over restart instances, which preserves lifetime anytime validity; spending over expert-creation order likewise controls multiplicity for unboundedly many experts. On synthetic multi-concept streams, Electricity, Covertype, and the recurrence-heavy INSECTS benchmark, the instance-accounted restarted bank achieves zero false spawns and zero false reuses after switches and matches or exceeds the retired windowed heuristic (INSECTS-reoccurring accuracy 0.675), making the deployed algorithm and the guaranteed algorithm one and the same.

cs.LG↗