Review Comment:
Manuscript swj4022
The manuscript introduces three modular RDF/OWL vocabularies: (1) DPP (Digital Product Passport) for ESPR-compliant product lifecycle traceability with UNTP alignment for sustainability metrics; (2) RMA (Return Merchandise Authorization) for service ticket workflows; and (3) WTY (Warranty & Contracts) for machine-readable warranty rules and automated payment decisions.
The principal contribution appears to be the introduction of wty:PaymentRule, which is intended to formalize warranty payment responsibility, payment percentage, defect type coverage, and cost categories. This is a potentially useful contribution because it moves beyond simple descriptive vocabulary design toward the representation of executable warranty logic. At the same time, the paper does not clearly show how this work is different from existing vocabularies, or whether related work has been reviewed well enough.
The manuscript also shows care in dissemination and publication practice. The vocabularies are presented as openly published resources with persistent identifiers, licensing information, and availability in multiple serializations. This strengthens accessibility and reuse potential and is a positive aspect of the work.
The paper states that the vocabularies have not yet been deployed in a production environment, that pilot implementations are planned for 2027, and that there are no third-party implementations. As a result, the work should be understood as an early modeling contribution rather than a validated practical solution. This does not invalidate the effort, but it clearly limits the strength of the manuscript’s claims regarding practical applicability and impact.
Main strengths include
• The ontologies are presented in clear modular structure. This separation gives the contribution conceptual clarity and improves the potential for selective reuse in different application settings.
• The wty:PaymentRule represents warranty payment responsibility and related conditions in a machine-readable form.
• The vocabularies are presented as openly published resources with persistent identifiers, licensing information, multiple serializations, and queryable access points. This is a clear strength because it improves accessibility and potential reuse.
• The work is aligned with existing standards including Schema.org, GS1-related identifiers, and UNTP-oriented concepts. Although the depth of this alignment is limited in the paper, the effort itself is relevant and constructive.
• The focus on Digital Product Passports and warranty-related machine-readable information is timely in light of the broader regulatory and industrial interest surrounding ESPR and product traceability.
Assessment of the provided resources and artefacts
The provided ontology artefacts support inspection of the proposed vocabularies and are presented through an accessible publication setup with persistent identifiers and multiple serializations. This is a strength of the submission. At the same time, the paper would benefit from clearer documentation of how the provided artefacts correspond to the ontology statistics, examples, and claims discussed in the manuscript. Clearer version transparency and more explicit guidance for readers assessing the ontology files would strengthen the submission further. The artefacts appear useful for inspection of the vocabularies, but the relationship between the paper and the provided resources should be explained more precisely.
Comments
Location: Throughout manuscript, particularly Sections 3-5 (Vocabulary Design and Implementation)
The paper makes strong claims about enabling "automated payment decisions" and "ESPR compliance" but does not provide sufficient validation of the proposed vocabularies. Without validation against real warranty contracts, relevant standards, ESPR requirements, or automation demonstrations, it is difficult to assess whether the vocabularies actually work. Also, the paper does not sufficiently show how the proposed vocabularies align with, extend, or differ from existing Digital Product Passport ontologies, standards, and related semantic models. Reuse and explicit alignment with relevant existing resources are important practices in ontology construction.
The paper includes illustrative examples, including a washing machine product passport and a warranty scenario with payment rules. However, these examples remain simple and author-constructed, and they do not amount to a rigorous validation of the vocabularies in realistic contractual or compliance settings. I think it is a good idea to demonstrate the claims made through realistic case examples, competency questions, or an executable assessment workflow. A stronger validation section is needed to show that the vocabularies are fit for their intended purpose and to clarify their interoperability potential.
Location: Section 4 and Table 5
The related work discussion is too narrow for a journal contribution of this kind. The comparative evaluation lacks sufficient detail to support the manuscript’s novelty claims. The related work discussion and Table 5 offer only a brief, high-level comparison. A more rigorous analysis is needed to clarify the necessity of the proposed approach and to justify the chosen modeling strategy over existing alternatives.
Location: Abstract, Introduction, Section 5.2, Figure 3, and Conclusion
The manuscript suggests that the proposed modeling can support automated warranty payment decisions, and Figure 3 provides a conceptual workflow for this purpose. However, the paper does not explain with enough technical precision how such automation would be carried out in practice. It does not provide executable rule examples, a worked reasoning trace, or a validation workflow that would substantiate this claim. It does not offer executable rule examples, reasoning demonstration, or a validation process that would support this assertion.
Location: Section 5
The illustrative examples are useful for explaining the proposed vocabularies, but they remain relatively simple and do not show how the model would handle more complex warranty situations involving layered responsibilities, richer conditions, or more elaborate decision paths. As a result, they are helpful as demonstrations of intent, but not as strong evidence of practical expressiveness.
Location: Sections 3 and 5, especially the description of WTY and the examples
The manuscript does not provide a sufficiently clear formal account of the semantics of wty:PaymentRule and related warranty constructs. The paper explains the intended meaning of the model at a descriptive level, but it remains unclear how payment responsibility, coverage conditions, exclusions, and assessment outcomes are meant to be interpreted in a formally precise and machine-executable way. This is important because the central contribution of the manuscript depends on these constructs carrying more than an implicit understanding. The author should clarify the formal interpretation of the core classes and properties and explain what kind of reasoning or rule execution model the design assumes.
Location: Sections 3 to 5 and the ontology artefacts more generally
The manuscript does not sufficiently distinguish ontology modeling from rule-based decision logic. This distinction is important because the paper presents warranty payment decisions as if they follow directly from the vocabulary design, while in practice such decisions usually depend on an additional rule layer, application logic, or validation framework. The manuscript should explain more clearly which aspects are handled by the ontology itself and which would require external rule execution, constraint checking, or application-level processing.
Conclusion
The paper addresses a timely and relevant topic by proposing modular RDF/OWL vocabularies for Digital Product Passports, return workflows, and warranty representation. Its strongest aspect is the attempt to model warranty-related payment logic in a machine-readable form, which gives the work some originality and practical promise. The modular design and the attention given to publication and dissemination of the artefacts produced are also positive features.
However, the paper remains too immature in its current form for acceptance. Its central claims regarding automation, interoperability, and compliance support are not supported by sufficient validation. The related work discussion is too limited to establish novelty convincingly, and the paper does not yet provide enough technical depth to explain how the proposed model would support automated decision making in practice. The examples are useful for illustration, but they are not strong enough to demonstrate practical expressiveness or real-world applicability.
Recommendation
Major revisions required
Reason for recommendation
In my opinion, the manuscript is not ready for acceptance in its current form because the main scientific contribution is not yet supported by adequate validation, comparative analysis, or technical demonstration. At the same time, the work is not without merit. The topic is relevant, the modeling effort is potentially useful, and the paper could become publishable if the author substantially strengthens the validation, clarifies the relation to existing vocabularies and standards, and provides a more precise account of how the proposed automation is intended to work.
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