Standards Compliance

1. Core SDC4 Standard

Semantic Data Charter (SDC4) Reference Model v4.0.0

Status: Proprietary Standard (Axius-SDC, Inc.)
Namespace: https://semanticdatacharter.com/ns/sdc4/
Formats: OWL ontology, RDF/Turtle, XSD 1.1 schema

SDC4 is a comprehensive reference model for semantic data modeling that combines object-oriented design principles, semantic web technologies, healthcare informatics patterns (adapted from openEHR/ISO 13606), and information exchange standards.

Key Capabilities:

• Hierarchical data structures via Cluster and XdAdapter patterns
• 15+ primitive and quantified data types (XdString, XdBoolean, XdQuantity, etc.)
• List types for efficient multi-value storage
• Spatio-temporal tagging at the data element level
• Access control metadata integration
• Provenance and audit trail support
• Multi-format output (XSD, XML, JSON, RDF, SHACL, GraphQL)

2. W3C Standards

RDF (Resource Description Framework)

Standard: W3C Recommendation | Version: RDF 1.1
Namespace: http://www.w3.org/1999/02/22-rdf-syntax-ns#

All SDC4 models are expressed as RDF triples with automatic RDF extraction from XSD schemas, triple storage in Apache Jena Fuseki triplestore, and SPARQL endpoint integration for semantic queries.

OWL (Web Ontology Language)

Standard: W3C Recommendation | Version: OWL 2
Namespace: http://www.w3.org/2002/07/owl#

SDC4 reference model expressed as OWL ontology with class hierarchies, property restrictions, cardinality constraints, and ontology versioning for formal semantic definitions and automated reasoning.

XSD (XML Schema Definition)

Standard: W3C Recommendation | Versions: XSD 1.0 and 1.1 (both supported)
Namespace: http://www.w3.org/2001/XMLSchema

Primary output format for data model schemas with XSD 1.1 support for assertions and conditional type alternatives, embedded RDF metadata in xsd:appinfo elements, and full namespace support.

SHACL (Shapes Constraint Language)

Standard: W3C Recommendation | Version: SHACL 1.0
Namespace: http://www.w3.org/ns/shacl#

Automatic SHACL shape generation from SDC4 models with property shape constraints (cardinality, datatype, pattern), node shape validation rules, and SPARQL-based constraint validation for RDF graph validation.

SPARQL (SPARQL Protocol and RDF Query Language)

Standard: W3C Recommendation | Version: SPARQL 1.1

Apache Jena Fuseki SPARQL endpoint integration with semantic search queries, update operations, and ontology service integration (BioPortal, Wikidata).

3. ISO Standards

ISO 21090 - Harmonized Data Types

Standard: ISO 21090:2011 - Health informatics - Harmonized data types for information interchange
Specification: HL7 V3 Data Types Release 2
Implementation Area: ExceptionalValue / NULL Flavor support

SDCStudio implements 15 ExceptionalValue types as OWL classes with hasExceptionalValue property for tagging invalid/missing data, enabling "quarantine-and-tag" validation approach that preserves invalid data for later correction.

ISO 8601 - Date and Time Format

Standard: ISO 8601:2004 - Data elements and interchange formats – Information interchange – Representation of dates and times

All temporal values use ISO 8601 format with XdTemporalType supporting 8 temporal representations including dateTime, date, time, duration, gYear, gYearMonth, gMonth, and gMonthDay for unambiguous temporal representation with timezone support and flexible granularity.

4. IETF/Internet Standards

RFC 3066 - Language Identification

Standard: IETF RFC 3066 - Tags for the Identification of Languages
Updated by: RFC 4646, RFC 5646 (BCP 47)

Mandatory dm-language tag for data models and optional language tags for XdString, XdToken, and XdFile values enable multilingual data support, proper text rendering and sorting, and cultural localization.

IANA Standards

IANA Character Sets Registry - encoding field support with UTF-8 default
IANA Media Types Registry - media-type field for embedded content supporting all registered MIME types (image/*, video/*, audio/*, application/*, text/*)

5. Industry Standards and Patterns

NIEM (National Information Exchange Model)

Organization: U.S. Department of Homeland Security, Department of Justice

SDC4 List Types are inspired by NIEM's list type pattern for efficient multi-value storage: XdBooleanListType, XdStringListType, XdTokenListType, XdIntegerListType, XdDecimalListType, and XdDoubleListType provide reduced XML verbosity and improved parsing performance.

Dublin Core Metadata

Organization: Dublin Core Metadata Initiative (DCMI)

Design-time metadata for data models including dc:title, dc:description, dc:creator, dc:date, dc:subject, dc:publisher, and dc:rights for standardized model documentation and discoverability.

6. Data Element Level Features

SDC4 enables standards-based metadata tagging at every data element in a model, not just at the document level. This fine-grained approach enables unprecedented data governance capabilities.

Spatio-Temporal Tagging

Geographic Coordinates (WGS 84): latitude and longitude properties enable geospatial health analytics, environmental health data correlation, mobile health data collection, and location-based data quality rules.

Temporal Metadata (ISO 8601): tr (time recorded), vtb (valid time begin), vte (valid time end), and modified properties support bitemporal tracking, sensor data with validity windows, audit trails, and GDPR "right to erasure" enforcement.

Access Control Tagging

act (Access Control Tag) property on all data elements with acs (Access Control System) URI links enable field-level encryption, column-level security, data masking, audit logging, consent management, and data residency compliance.

7. Standards Enabling Semantic Interoperability

Ontology Integration

Supported Sources: BioPortal (200+ biomedical ontologies), SNOMED CT, LOINC, ICD-10, RxNorm, and Wikidata with pred_obj (Predicate-Object) relationships linking data elements to ontology terms via RDF properties.

GraphQL Schema Generation

Standard: GraphQL Specification (June 2018)

Automatic GraphQL schema generation from RDF triples with type definitions, query resolvers, and nested relationship traversal for modern API standards with efficient data fetching and strongly typed, self-documenting APIs.

8. Validation and Quality Assurance Standards

XML Validation

sdcvalidator 4.0.1 - SDC4-enhanced XSD validator extending xmlschema library with ExceptionalValue error recovery and ISO 21090 NULL Flavor support

Validation Levels: Well-formedness, Schema validation, Semantic validation (SHACL), and Business rules

RDF Validation

pyshacl 0.30.1 - SHACL validation engine with closed-world, open-world, shape-based, and rule-based validation approaches

9. Compliance Benefits

10. Standards Reference Matrix