Working towards the next version of the SWIM Supporting Material

Page tree

Working towards the next version of the SWIM Supporting Material

Skip to end of metadata
Go to start of metadata

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 18 Next »

Error rendering macro 'excerpt-include'

No link could be created for 'SITCOM Task Status'.


The opportunity

It is not clear in which order to read traces when there are more than one in a single semantic correspondence statement. Some traces are, in fact, qualifiers of other traces.

Is it possible to:

  • somehow differentiate the traces and
  • apply a reading order?

Discussion

The discussion has been split into parts to make easier to follow.

Assumptions

The traces are to be read by humans/machines

The traces are to be created by humans/machines

Different types of traces

  • Can we survive with just using these names that are inspired by the words in the spec?
  • Can we merge the two types of "concept" traces into one name?
  • The use of the word "concept" as a qualifier name could be misleading. The background section below contains alternative suggestions.

The table below uses the words from the SWIM Information Specification's requirements.

RequirementTrace requiredTrace nameDefinition
SWIM-INFO-016 Mapping of information conceptsrequires one concept trace"information concept" tracetrace from the information concept in the information definition to the AIRM concept that has an equivalent or wider meaning
SWIM-INFO-017 Mapping of data concepts

requires one concept trace and one data type trace

  1. "data concept" trace
  2. "data type" trace
  1. trace from the data concept in the information definition to the AIRM concept that has an equivalent or wider meaning
  2. trace to the data type in the AIRM that has an equivalent or wider meaning
SWIM-INFO-018 Additional traces to clarify the mappingallows any number of additional clarifying traces"additional" tracetrace to an AIRM concept to fully describe the narrowing of the concept being mapped

Source and target of traces

The Interoperability Architecture provides good advice. Basically, trace to the adjacent box by default.

The usual start point depends on the requirement being fulfilled.

Trace nameSourceTarget
"information concept" traceLikely sources: information exchange requirements

Best place to start: Conceptual Model.

If not found there, use Contextual Model or Logical Model

  1. "data concept" trace
  2. "data type" trace
Likely sources: service message

Best place to start: Logical Model.

If not found there, use Contextual Model or Conceptual Model for the "data concept" trace
"additional" tracesource depends on the trace being clarified

Should be in the same model as the trace being qualified.

Reading order of traces

General reading order is:

  1. "information concept" trace
  2. "additional" traces

or

  1. "data concept" trace
  2. "data type" trace
  3. "additional" traces

All traces have an AND relationship.

Level of semantic correspondence

Advanced users may like to add extra detail concerning the level of semantic correspondence achieved. The requirements talk about "equivalent or wider meaning". The table below contains the old AIRM Rulebook names and the skos equivalents.

Definition being traced to is...Annotations that can make this more explicitor in skos
Equivalent
  1. ExactCopy: Definition of concepts in the information definition and the AIRM are exact copy of each other.
  2. SyntacticallyEqual: Definitions are only different due to syntax corrections (grammar, spelling) but are otherwise equivalent.
  3. Rewritten: The definition of the concept in the information definition has been rewritten to reflect information definition specificity. However, the meaning is the same, i.e. the definition still describes exactly the same concept as the AIRM.
  1. skos:exactMatch: is used to link two concepts, indicating a high degree of confidence that the concepts can be used interchangeably across a wide range of information retrieval applications.
  2. -
  3. skos:closeMatch: is used to link two concepts that are sufficiently similar that they can be used interchangeably in some information retrieval applications.
WiderSpecialised: The definition in the information definition is a special case of the definition found in the AIRM.narrowMatch:
used to state a hierarchical mapping link between two concepts.

We only need additional traces if the main trace is "specialised"

Traces cannot be annotated as "generalised" as this breaks the requirement.

Annotating traces

It is possible to add a further notes to the mapping (or trace?). This comes in handy for example when e.g. tracing legacy interfaces that have data type constraints leading to loss of Information.

Representing traces in XSD

How should the different traces be represented in the XSD examples we use? The table below gives two alternatives.

If this is a best practice, the attribute option is probably preferable - the attribute can be optional and the name of the element is always <trace>

Trace nameElement nameAttribute
"information concept" trace<informationConceptTrace><trace keyword="informationConceptTrace>
  1. "data concept" trace
  2. "data type" trace

<dataConceptTrace>

<dataTypeTrace>

<trace keyword="dataConceptTrace>

<trace keyword="dataTypeTrace>

"additional" trace


<additionalTrace>

<trace keyword="additionalTrace>

Full example

If we apply all of this:

<xs:annotation>
  <xs:documentation>
    <semanticCorrespondence>
      <mapping note="loss of info because of legacy">
        <informationConceptTrace degree="specialised">-AIRM unique identifier-</informationConceptTrace>
        <additionalTrace>-AIRM unique identifier-</additionalTrace>
      </mapping>
    </semanticCorrespondence>
  </xs:documentation>
</xs:annotation> 

or:

<xs:annotation>
  <xs:documentation>
    <semanticCorrespondence>
      <mapping note="loss of info because of legacy">
        <trace type="informationConceptTrace" degree="specialised">-AIRM unique identifier-</informationConceptTrace>
        <trace type="additionalTrace">-AIRM unique identifier-</additionalTrace>
      </mapping>
    </semanticCorrespondence>
  </xs:documentation>
</xs:annotation> 

Example of tracing exercise

However it should be consistent with the information given at the AIRM homepage. Links to the according pages will also help.

This is probably handled as a separate activity after the current task is completed.

Background

Existing qualifier names

Different artefacts have used different trace "qualifiers".

Example 1

  1. "Data Traces", which, for the case of SWIM-INFO-017, refer to the Data Type constraints. They must be unique, and may already also contain the full definition (as the best matching AIRM concept with the correct data type constraint will be chosen), so they are logically first in line.
  2. "Definition Traces" which point to the comprehensive or even normative definition (when available) or to the best matching wider AIRM concept (in both SWIM-INFO-016 and SWIM-INFO 017). They must be present and must be unique, so they are next in line (top of the line for SWIM-INFO-016 actually).
  3. "Context Traces" that add qualifiers (i.e. implement SWIM-INFO-018). These are optional, and their order should not have semantic significance.

Example 2

The Donlon example at https://ext.eurocontrol.int/swim_confluence/display/SWIM/Donlon+TOBT+Setting+Service+Description#DonlonTOBTSettingServiceDescription-InformationDefinition is almost the same. It uses:

  1. AIRM Semantic Trace
  2. AIRM Definition Trace. This seems to be in line with what Stefan mentioned above.
  3. AIRM Context Trace. This appears to add the qualifiers as mentioned by Stefan above.

Example 3

Looking at the ISRM (Information Service Reference Model) it has:

  1. Main CLDM mapping. The mandatory and unique CLDM mapping indicating the AIRM element having the type of data as the OuA construct. E.g. a “time” for TSAT;
  2. Context CLDM Mapping. One or more optional additional CLDM mappings helping achieving a more accurate semantic definition by giving more context to the main CLDM mapping. E.g. the “TARGET” planning status for TSAT;
  3. IM Definition Mapping. An IM mapping allows referencing a unique IM element containing a normative definition (typically from ICAO) for the OUA construct. Can be optional or mandatory depending on contexts as explained in next chapters.

Example 4

EUROCAE ED-254.

The mappings to the AIRM have the following keywords:

  1. SemanticTrace
  2. DefinitionTrace
  3. ContextTrace (which can be further defined as ContextTrace_1, ContextTrace_2, etc)

Keyword: DefinitionTrace.

Value: URN of an AIRM information or data concept

Usage Notes: This will normally point to a resource in the AIRM Information Model, i.e. an AIRM information concept. However, occasionally (e.g. when mapping the definition of certain containers), it may necessary to refer to the definition part of a (CLDM) data concept. In this case, the data type of the AIRM trace target is not part of the trace semantics.

Keyword: SemanticTrace

Value: URN of an AIRM data concept

Usage Notes: When there is no accompanying DefinitionTrace, it is understood that both SWIM-INFO-016 and SWIM-INFO-017 are implemented by this trace (see note on SWIM-INFO-017)

Keyword: ContextTrace / ContextTrace_n

Value: URN of an AIRM information or data concept

Usage Notes: The first form is the standard.  When more than one context traces is required on an element, the second form is used. The EUROCAE document does not formally associate business semantics with data entities, i.e. all data entities are implicitly traced to “OutOfScope: container”. The mappings of individual data fields are therefore self-contained, there is no “trace cascading”.

How many qualifiers

Can’t we survive on:

2 categories:

  • “trace” (1 or more to either AIRM-CM or AIRM-LM; note that the URN shows whether CM or LM)
  • “trace_qualifier”

In the schema trace and trace_qualifier could then be differentiated.

2 best practices:

  • Order best practice: “widest first”
  • Qualifier best practice: “Trace qualifier directly after qualified trace”

Adding notes to mappings

It is maybe worth noting here that sometimes you want to put a comment on a mapping, so I am allowing this as an extra annotation. This comes in handy for example when tracing legacy interfaces that have data type constraints leading to loss of Information.

Perhaps we need to look at what "aspects" of the AIRM model are mappable to first -  and also possible the level of alignment (eg exact, broader, etc aka SKOS-like).

From old AIRM rulebook

AIRM_Rule 60

The 'Definition:Adapted' AIRM::TaggedValue shall be completed in order to indicate the level of semantic correspondence with the source definition. The list of values is:

  • ExactCopy: Definition of source and target are exact copy of each other.

  • SyntacticallyEqual: Syntax corrections (grammar, spelling)

  • Rewritten: The definition has been rewritten for improved quality. The meaning is the same, i.e. the definition still describes exactly the same entity as the target definition.

  • Specialised: Source definition is a special case of the target definition.

  • Generalised: Source definition is a generalised case of the target definition.

AIRM_Rule 116

A data or information construct is considered to be in semantic correspondence with the AIRM if one of the following conditions holds:

  1. The definition of the construct is an exact copy of the definition of a specific AIRM element, or it is syntactically equal, or is rewritten or is specialised as described in AIRM_Rule 60.

  2. It can be demonstrated that the definition of the construct can be decomposed into several elementary concepts, each corresponding to an AIRM element as per previous bullet. This decomposition must be comprehensive, i.e. cover all parts of the definition.

  • No labels