CTS 2 Status Report Presentation to HL7 Vocab WG Jan 11, 2011 Harold Solbrig Mayo Clinic

CTS2

Status ReportPresentation to HL7 Vocab WG

Jan 11, 2011Harold Solbrig

Mayo Clinic

© Copyright 2011, Mayo Clinic 2

Outline

• Background and Approach• Specification outline via. Compliance points• Status

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Background and Approach

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CTS2

BackgroundCommon Terminology Services Edition 2Evolved from:• OMG LQS Specification (1999)– OO Model, read only, but laid most of the

groundwork• HL7 CTS Specification (2004)– ANSI and ISO Standard– SOA Model, read only, reduced scope from LQS

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CTS2

Brief HistoryWorking through the HSSP Process• Issued by HL7 as a SFM Fall 2009• RFP issued by OMG 2010• Preliminary submissions June 2010– Mayo– II4SM

• Final submissions (currently) due Feb 21, 2011– For March OMG meeting

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CTS2

General Requirements• CTS Functionality (but not signatures)• Ontology versioning and incremental update• “Authoring”• Data binding model (HL7 value sets / ISO

11179)• Reasoning and inference

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CTS2

Additional Drivers and Requirements• NCI/Mayo LexEVS compatibility• Semantic Web / Ontology community buy-in• BioPortal compatibility

– RESTful compatible architecture• II4SM Model

– Reasoning– Z representation

• OMV alignment• API4KB Alignment• IHTSDO Alignment• Addl: Phin VADS, HL7 MIF, IHE Implementations and Profiles (SVS)

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Approach

PIM – “Platform Independent Model”, mapped to multiple Platform Specific Models (PSMS):

• REST • SOA(p)• iRDF

Specification – combination of UML, text and Z

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Challenges

What, exactly is a PIM?How do we create one model that aligns with

REST (our primary target), SOA(p), RDF minimalists and POJO?

No easy answers, but Z specification seems to help considerably

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Other Challenges

LexEVS – built, runs and already incorporates a significant portion of what is in the requirements

• LexEVS (XML / POJO) to PIM is a non-trivial transformation

• Reproducible behavior is a non-trivial processDecision was made to build CTS2

implementation on top of LexEVS vs changing core API

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Before we get started

Specification approachUML / text / Z– UML provides structure– Z provides invariants, preconditions, postconditions

(behavioral semantics)– Text describes structural components and restates Z in

formal text

Do I need to know Z to read it?– No, but the Z is normative and can be used when

text is unclear

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PDF Example

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Compliance

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Compliance

Resource orientation provides fine-grained implementation / compliance points

• Resource Axis – Which resources are represented by the service

• Functional Axis - What functionality the service provides

• Representational Axis – How the resources are represented

• Structural Detail – Structured [+ “semi”-structured + [RDF]]

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ComplianceResource Axis

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ComplianceResource Axis

Service provider can implement any combination of:

Code System – metadata about code system (ontology) purpose, provider, release cycle, etc.

(rdf:type skos:ConceptSystem or Owl:Ontology)Code System Version – metadata about a

collection of statements (ontology) . (rdf:type skos:ConceptSystem or Owl:Ontology)1/10/2011


ComplianceResource Axis (cont)

Entity – structured assertions about classes / individuals and/or predicates

. (rdf:type skos:Concept, owl:Class, owl:Individual, rdf:Predicate)

Association – metadata about a collection of statements about Entities

(rdf:type rdf:Statement where rdf:subject type Entity)

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Value Set – metadata about set of entity references

. (rdf:type iso11179:EnumeratedConceptDomain)

Value Set Definition – rules for constructing a value set

. (rdf:type ???)

Value Set Resolution Rule - rules for applying a value set definition in a particular context

. (rdf:type ???)1/10/2011



Concept Domain – metadata about the scope, purpose, etc. of a data element concept

(rdf:type iso11179:DataElementConcept)

Concept Domain Binding – contextual association between a concept domain and a value set.

(rdf:type iso11179:DataElement)

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Mapping – metadata about a set of relationships between classes, roles and/or individuals in two or more ontologies

Mapping Version – collection of relationships for a mapping at a given point in time

Mapping Entry – an assertion about how a source entity maps to one or more targets

Zed.sty

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ComplianceFunctional Axis

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ComplianceFunctional Axis

For a given resource:• Read - return resource by identifier• Query – directories w/ constraints• Authoring – construct change sets• Import / Export - from external sources and formats• Incremental Update – load change sets• History – change history of a resource• Temporal – state of service at point in time• Resource Specific – advanced association services,

etc.1/10/2011


ComplianceRepresentation Axis

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Resource Representation:• XML• JSON• RDF• (i)RDFTarget Functional Representations:• Web XML (aka. “REST”)• SOAP – interesting question of service (verbs) vs. REST via

Web Services• POJO

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Still an outstanding issue on granularity• PIM is (more or less) agnostic when it comes

to granularity…• … invariants / preconditions / postconditions

are the same whether you lump or split the operations

• SOA / REST granularity can be choreographed• … so how far do we need to go?

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ComplianceStructural Detail

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Structural Detail

1) Traditional UML / XML Structure2) Collection of Structured Statements

- Resource predicate target- Provenance, modifiers, …

3) (i)RDF- “cannonical” RDF rendering of statements w/o provenance, history

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Status

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Current Status

Specification is still undergoing significant change• Remaining faithful in spirit to the June submission• UML model is approaching a (relative) steady state• Z and document are undergoing a major

restructuring – targeting week of Jan 17 for new publication available

Will be discussing Feb 21 deliverable w/ external drivers• Feedback vs. Availability• There may be a workable compromise

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Status

• Fundamental Model and Functionality remains consistent with first submission(s)

• Work continues on:– Refactoring and refinement: each community has

its own needs and “non-negotiables”– Naming: each community has its own names– Formal semantics: a precise specification is a lot of

work• .1/10/2011


Some Notes on Process

• OMG process is “pay to contribute”• Submitters ok w/ external review, tire-kicking,

trial implementation, etc.

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Model Walkthrough

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RESTful Implementation

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© Copyright 2011, Mayo Clinic 341/10/2011




Documents

CTS 2 Status Report Presentation to HL7 Vocab WG Jan 11, 2011 Harold Solbrig Mayo Clinic