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  <front>
    <journal-meta>
      <issn pub-type="ppub">1613-0073</issn>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Exploring Semantic-Enhanced Property Graphs in Network Operations</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Beyza Yaman</string-name>
          <email>beyza.yaman@adaptcentre.ie</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Michael Mackey</string-name>
          <email>michael.mackey@huawei.ie</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Peter Cautley</string-name>
          <email>peter.cautley@huawei.ie</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Declan O'Sullivan</string-name>
          <email>declan.osullivan@adaptcentre.ie</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>ADAPT Centre, Trinity College Dublin</institution>
          ,
          <addr-line>Dublin</addr-line>
          ,
          <country country="IE">Ireland</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Huawei Ireland Research Centre</institution>
          ,
          <addr-line>Dublin</addr-line>
          ,
          <country country="IE">Ireland</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2025</year>
      </pub-date>
      <fpage>2</fpage>
      <lpage>6</lpage>
      <abstract>
        <p>Telecommunication networks face significant challenges in performing root cause analysis due to their complexity, data heterogeneity, and high-volume event streams. This paper presents a comparative evaluation of the Semanticenhanced Programmable Graph (SPG) paradigm, implemented via the OpenSPG engine, which integrates the structural advantages of property graphs with semantic constraints inspired by RDF ontologies. Through a practical telecom use case, we demonstrate SPG's strengths in event-centric modeling and causal reasoning. However, our analysis reveals notable trade-ofs, particularly in semantic interoperability, reasoning capabilities, and tooling maturity compared to established RDF standards. We conclude that while SPG is a promising model for performance-driven, internal domains like telecom operations, its current limitations reduce the universality that is a hallmark of semantic web solutions. Our findings ofer critical insights into the applicability of OpenSPG and highlight key considerations for developing future semantic-enabled network management solutions.</p>
      </abstract>
      <kwd-group>
        <kwd>ontology</kwd>
        <kwd>schema</kwd>
        <kwd>rdf</kwd>
        <kwd>property graphs</kwd>
        <kwd>semantic enhanced property graphs</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Systems</title>
      <p>In complex systems such as telecommunications networks, maintaining operational reliability requires
not only detecting issues early but also understanding their underlying causes. Root cause analysis
(RCA) in the telecom domain faces several challenges due to the scale, complexity, and heterogeneity of
modern network infrastructures1. Telecom networks generate significant volumes of event data from
diverse and distributed sources, often in inconsistent formats and without unified semantics. Events are
highly interdependent, with cascading efects across diferent layers (e.g., management, control, and
data), making it dificult to isolate the origin of faults. Correlating this data across diferent sources,
understanding service and customer impact, and preserving contextual information such as interface
roles or link functions are particularly dificult. Additionally, the dynamic and real-time nature of
network operations requires RCA methods that are not only accurate but also scalable and responsive.
Integrating domain knowledge and semantic context remains a key challenge for building explainable
and automated RCA systems in telecom. Addressing these limitations demands graph-based approaches
that can efectively represent event dependencies and domain knowledge.</p>
      <p>
        In the domain of graph-based knowledge representation, two primary models are RDF [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] and Labeled
Property Graphs (LPG) [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], which difer in their trade-ofs between semantic richness and performance
[
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Building on this foundation, recent research has explored applying such semantically enriched graph
models to real-world network management scenarios, highlighting the growing interest in telecom
operations. Martínez et al. [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] introduced the YANG Server Ontology to model YANG-based network
servers and their NETCONF interactions, providing integration guidelines for RDF Mapping Language
(RML) mappings [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. They also proposed CANDIL [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], a federated data fabric that unifies heterogeneous
      </p>
      <p>
        ceur-ws.org
network data into a knowledge graph using shared ontologies, validated through Edge-Cloud analytics
use cases. The NORIA-O model [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] supports representing network infrastructures and events, though
its generality poses challenges for consistent multi-domain integration.
      </p>
      <p>
        RDF enables reasoning and interoperability through subject–predicate–object triples and ontologies,
while LPG provides flexibility and scalability with key-value properties on nodes and edges. However,
RDF’s query ineficiencies [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] and LPG’s lack of formal semantics limit their standalone applicability in
domains like telecom. Recently, a hybrid approach, namely Semantic-enhanced Programmable Graphs
(SPG), has been proposed to bridge this gap [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. SPG builds on LPG’s structure while incorporating
semantic constraints similar to ontologies, making it well-suited for event-driven domains such as the
telecom domain, where modeling causal, temporal and hierarchical relations between events is critical.
This involves augmenting property graphs with semantic schemas, resulting in a hybrid model that
integrates the structural simplicity of LPG with semantic constraints derived from RDF ontologies [
        <xref ref-type="bibr" rid="ref3 ref9">3, 9</xref>
        ].
In the following section, we will give a brief introduction to the OpenSPG engine investigated within
this project.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. OpenSPG: A Semantic-Enhanced Programmable Graph Engine</title>
      <p>
        OpenSPG is a knowledge graph engine based on the SPG approach to improve industrial applicability
[
        <xref ref-type="bibr" rid="ref10 ref9">10, 9</xref>
        ]. In this study, the OpenSPG engine2 was chosen to explore our use case and compare the SPG
approach with the well-established RDF model. OpenSPG was selected for its open-source availability
as the first engine based on the SPG approach, and for its suitability in enhancing property graph-based
projects with semantic capabilities. OpenSPG integrates logical-form parsing, symbolic computation,
and retrieval-augmented generation to enable accurate and interpretable question answering in
domainspecific contexts using KAG (Knowledge Augmented Generation) which is a reasoning framework
developed on top of OpenSPG. It supports a unified representation of structured data, unstructured
text, and expert-defined knowledge within a schema-constrained knowledge graph. The system
architecture comprises two primary modules: the kg-builder, which extracts and integrates knowledge
from heterogeneous sources through schema-guided or schema-free methods; and thekg-solver, which
translates natural language queries into executable logical forms, enabling a combination of graph
traversal, symbolic reasoning, and neural generation. This architecture enables the system to respond
to natural language queries by leveraging large language models (LLMs) within a retrieval-augmented
generation (RAG) framework, combining symbolic reasoning over structured knowledge graphs with
neural language generation to support accurate and contextually grounded answers.
      </p>
    </sec>
    <sec id="sec-3">
      <title>3. Lessons Learned</title>
      <p>
        As both RDF and SPG ofer distinct modeling philosophies and capabilities, we compare them along
several criteria relevant to building explainable and performant root cause analysis systems in telecom
(see Table 1). From this comparison as well as a proof of concept implementation for a preliminary
router operations use case given in the previous paper [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ], as well as, Github repository3, several key
lessons have emerged.
      </p>
      <p>
        OpenSPG aims to support rapid development of enterprise-level knowledge systems by modeling the
full knowledge lifecycle [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. While the preliminary use case was successfully implemented, a number
of lessons are worth sharing. The tool presents a steep learning curve, requiring several weeks to learn
and master the main concepts for a developer. Limited community support and documentation at the
moment further hinder usability.
      </p>
      <p>OpenSPG emphasizes event-centric domain modeling, using context-specific and action-oriented
relationships to represent entities and their interactions in dynamic systems such as networks. The
relationships in OpenSPG engine are more focused on practical domain modeling rather than formal
2https://github.com/OpenSPG
3https://github.com/beyzayaman/openspg
logical reasoning. They are designed to capture the semantic meaning of entities and events in
specific contexts (such as supply chains, business processes, or network systems). OWL relationships
(properties) are defined within a formal ontology and support logical reasoning. It provides a more
rigorous logical framework for relationships, including subclassing, inverse properties, and cardinality
constraints. OpenSPG engine relationships are often more action-oriented (e.g., “locateAt”, “mannerOf”)
and tailored for real-world systems where event-driven analysis is key. Both support inheritance (is_a
in OpenSPG engine, rdfs:subClassOf in RDFS/OWL) and enforce domain and range constraints for
semantic consistency.</p>
      <p>Our use of SPG’s built-in schema and property constraints (e.g., enforcing node types and expected
properties) helped uncover obvious data issues like missing identifiers or incorrect links. However,
these validations are relatively shallow compared to what RDF technologies like SHACL can provide.
SHACL allows declarative, expressive constraints (e.g., cardinality, value ranges, conditional constraints)
and supports reusable constraint templates. Thus, currently OpenSPG lacks the mature data validation
capabilities of RDF+SHACL, which are crucial in high-integrity domains like telecom.</p>
      <p>In terms of uplift of data, although OpenSPG supports loading data from relational tables (MySQL),
the alignment of column names to schema properties was found to be non-trivial in our use case.
Schema mismatches or missing property definitions led to runtime errors or silent omissions in graph
construction. Successful data ingestion required iterative tuning of schema-property alignment and
index strategies.</p>
      <p>On the other hand, limited interoperability complicates integration with external linked data sources
and the reuse of public RDF datasets, primarily due to the absence of shared vocabularies and standard
query protocols like SPARQL. While this constraint is often acceptable in closed, performance-oriented
environments, it sacrifices the cross-system compatibility central to the semantic web vision.</p>
      <p>In the implementation of our use case, we generated sample instances for each class and loaded
them into OpenSPG. A total of 9 classes (including events, entities, and concept types) and 35 relations
were defined for the use case. Among these relations, 4 were logically inferred rather than physically
created, meaning they were derived through reasoning instead of being explicitly stored in the data.
Due to the built-in vectorization for natural language querying, the data insertion into Neo4j was
time-consuming (e.g., 15 minutes for 40KB on an 8GB RAM system). Additionally, query performance
degraded significantly when primary keys were omitted, highlighting some current limitations in
OpenSPG’s query optimization. Overall, despite our initial findings, our experience of using OpenSPG
for our network scenario holds promise, and further exploration will be undertaken as the engine and
supporting documentation evolves and matures. Despite its current immaturity, OpenSPG ofers value
for projects already based on property graphs seeking enhanced semantic capabilities.</p>
      <p>Feature SPG-Schema Ontology-based Schema
Schema Definition Hybrid model: Combines elements of RDF schemas Strict ontology-driven: Uses RDF Schema (RDFS) and
and Property Graphs with controlled semantics. OWL for defining classes, properties, and constraints.</p>
      <p>Data Model Property Graph with semantic enhancements (sup- Triple-based (subject-predicate-object) with strict
onports labels, relationships, and typed attributes). tological constraints.</p>
      <p>Reasoning &amp; Inference Supports programmable reasoning (SPG-Reasoner) Strong reasoning using RDFS entailment, OWL DL,
using KGDSL, enabling custom rules and hybrid AI- and SPARQL inferencing. Supports logical inference
symbolic reasoning. but can be computationally expensive.</p>
      <p>Query Language KGDSL (Knowledge Graph DSL) + Property Graph SPARQL (standard for RDF queries).</p>
      <p>queries (Cypher, Gremlin).</p>
      <p>Challenges - More complex than traditional Property Graphs. - - Performance bottlenecks when reasoning. -
Difi</p>
      <p>Steep learning curve due to hybrid schema. cult to manage for fast-changing data.</p>
      <p>Flexibility vs. Control Balanced: Provides schema control, allows extensions. Highly controlled: Strict ontology-based constraints.
Expressiveness Supports semantic constraints but retains flexibility High expressiveness due to OWL-based reasoning,
for graph traversal. with complex class hierarchies, rules, and inference.
This research received funding from Research Ireland [grant number 24/IRDIF/13114] and ADAPT
Researchers are partially funded by the European Regional Development Fund through the ADAPT Centre
for Digital Content Technology [grant number 13/RC/2106]. We appreciate the helpful discussions
and collaboration from Anatolii Parerva, Bunyarit Puangthamawathanakun, Francesco Landolfi, and
Shengyang Chen.</p>
    </sec>
    <sec id="sec-4">
      <title>Declaration on Generative AI</title>
      <p>During the preparation of this work, the authors used Chat-GPT-4 in order to: Grammar and spelling
check. After using these tool(s)/service(s), the authors reviewed and edited the content as needed and
take full responsibility for the publication’s content.</p>
    </sec>
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