MatML version 3.0 schema

50 Pages·2.1 MB·English

by  Begley, E. F.

NISTIR 6939
MatML
Version 3.0 Schema
E.F. Begley
QC
NIST
/£>6
LL$l> National Institute of Standards and Technology
Technology Administration, U.S. Department of Commerce
o?0O3

NISTIR 6939
MatML
Schema
Version 3.0
E.F. Begley
Building EnvironmentDivision
Building andFire Research Laboratory
January 2003
DEPARTMENT OF COMMERCE
U.S.
DonaldL. Evans, Secretary
TECHNOLOGY ADMINISTRATION
Phillip J. Bond, Under Secretaiy ofCommercefor Technology
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY
Arden L. Bement, Jr., Director
4*
Introduction
What isMatML?
On01 October 1999, theNational Institute ofStandards and Technology (NIST) initiatedthe development
ofMatML, amarkup language forthe managementandexchange ofmaterials property data. AtNIST, the
needforsuchamarkup language becameevidentinMay 1997 duringthe development ofthe Ceramics
WebBook1 whichincludes databases ofevaluateddataforadvancedceramics, a guide to materials data
,
centers and sources, and acollection ofmaterials-relatedtools andresources. It was duringthe May 1999
ASTM-NISTWorkshopon Materials Datain the Internet Age, however, when it became clearthere were
manyindependentrealizations that amaterials data markup language was needed. Afewmonths later,
NIST addressedthis needbylaunchingthe MatMLdevelopment project. The first orderofbusiness was
the assemblyofan international working group composed ofmaterials dataexperts. The MatMLWorking
Group's central activities were to determine the scope ofMatML's applicationandto formulateits
vocabulary and syntax. There was anespecially strongemphasis duringthe working group discussions
that: MatMLoughtto be flexible in the scope ofits application, i.e., thatit couldbe usedto markup awide
varietyofmaterials datafromabroad range of
sources; MatML's vocabulary shouldbe <P>
materials-orientedandeasyto learn; and 1350<br>
metakbo
MatML's syntax mustbe extensible to
aluminum alloy<br>
accommodate both alternative andunanticipated ASTM B230<br>
forms ofmaterials data andtheirrepresentation. H18<br>
From“PropertiesofAluminumAlloys-Tensile, Creep, and
Perhapsthe best wayto describe MatMLisby Fatigue DataatHigh and LowTemperatures.”<br>
Axial-Stress Fatigue Strength (ksi)<br>
example andincontrast to HTML. Materials <table>
propertydatadistributedonthe WorldWide <tr><td>23</td></tr>
Web indocumentsusing hypertext markup <tr><td>17</td></tr>
language (HTML) present two problems for <tr><td>15</td></tr>
</table>
computerapplicationsintendingto use the data:
interpretationandinteroperability. Fig. 1: Aluminumalloy data in HTML
HTML
Figure 1 contains an code fragmentfor
aluminumalloydata. Sincethe data are not self-describing, one wouldneed acomplete datadictionaryand
glossaryofterms as well asexact detailedknowledge ofthe document structure in orderto write a
cbeomnpeucteesrsaarpypltiocdaitsitoinntghuaitshustehsetdheessceridpattoarswiotfhtohuetmhatuemraianli(n1t3e5rv0e,ntmieotna.l,IanlFuimgiunreum1,alfloory,exAamSpTleM,Bit23w0o,uld
H18) fromthe propertydata (table ofaxial-stress fatigue strengthsinksi units). Assumingaconsistent
structure withinand across documents fromthe datasource, it would thenbe possible to parse and interpret
those dataprogrammaticallyforsubsequentuse in anothercomputerapplication. In absence oftightlyand
consistently structureddocuments, adatadictionary, and aglossaryofterms, however, interpretation arises
as akey stumbling blockforautomateduse ofthe materials propertydatacontainedin HTMLdocuments.
Ifinterpretationofdatawere notanissue, the computerapplicationdevelopedto parse anduse the data
wouldlikely encounterserious difficulties were ittotryusingdatafromotherstructurallydissimilar
sources. Interoperability, then, wouldbe alimitingconditionforthe use ofthe computer application across
structurallydissimilardata sources evenifdatadictionaries andglossaries ofterms were available.
MatMLaddresses the problems ofinterpretation andinteroperabilityformaterials propertydataexchanged
viathe WorldWide Web. The example given inFigure 1 mightbe coded asinFigure 2 and would allow
an applicationtointerpret anduse materials dataregardless oftheirsources.
1 See:http://www.ceramics.nist.gov/webbook7webbook.htin
1
HTMLtags specify only howthe data are to be formattedfordisplay andconvey nodescription ofthe data
themselves. While this aspect ofHTMLhas enabled the publication ofbillions ofweb documents, it,
nonetheless,represents a
<MatML_Doc> serious drawbackto those who
<Material> wish to automate the
<BulkDetails> processingofthe data
<Name>1350</Name>
containedin those documents.
<Class>metal</Class>
<Subclass>aluminumalloy</Subclass> To address this problem, the
<Specification>ASTM B230</Specification> Extensible Markup Language'
<ProcessingDetails> (XML) was developed and
<Name>H18</Name> released bythe World Wide
</ProcessingDetails> Web Consortium1 (W3C), an
<PropertyDataproperty=”p1”source=”s1”>
<Dataformat="integer”>23,17,15</Data> international group of
</PropertyData> approximately 500 member
</BulkDetails> organizations dedicatedto
<Metadata>
developing commonprotocols
<DataSourceDetailsid=”s1”>
<Name> thatpromote the evolution of
“PropertiesofAluminumAlloys-Tensile, the Web andensure its
Creep, and Fatigue Dataat High and Low interoperability.
Temperatures.”
</Name>
XML
</DataSourceDetails> enables communities,
<PropertyDetailsid=”p1”> such as materials scientists and
<Name>Axial-Stress Fatigue Strength</Name> engineersinthe case of
cllnits name=”ksi” Description=”kippersquare inch”> MatML, to define theirown
<Unit>kip</Unit>
<Unitpower=”-2”>inch</Unit> domain-specific tags and
</Units> document structure, i.e., they
</PropertyDetails> can create theirown languages
</Metadata>
fordatamanagement and
</Material>
</MatML_Doc> exchange that, in turn, permit
efficientparsing and
Fig. 2: Aluminum alloy data inMatML interpretationofthose data via
software.
The descriptive nature ofthe MatMLtags, such as <Name>, <Class>, and <Subclass> is plainlyevident,
permittingthe language tobe far more intelligible than non-descriptive fixed tagsets suchas HTML. Atthe
same time. MatMLdefines acoherent and consistent document structure forits tags, whichensuresthat
anyprogramming language can be usedto parse and process the datain whatever mannerrequired. The
formal specificationforMatML 3.0 Schema, whichcovers syntax and semantics, is provided in Appendix
A.
MatMLDevelopmentHistory
The mostimportant attribute ofthe MatMLdevelopment effort was the inclusion ofabroadrange ofinput
fromthe materials community. These individuals andgroupsrepresented private industry, government
laboratories, universities, standards organizations, and professional societies, and theirefforts were
coordinatedbyNIST.
The initial strategyforMatML's developmentincludedthe establishment ofa working group (Table 1) that
delineated the scope and specifications forthe new language from which MatML was developed. On 28
April 2000, an initial workingdraft ofthe language. AnnotatedMatMLDTDVersion 1.0 (MatML 1.0),
wasreleasedforcomment. In response to working group feedback, a second versionofMatML, Annotated
MatMLDTD Version 2.0 (MatML2.0), was releasedon 29 March 2001. Afew months later, on 26-27
2See:http://www.w3.org/XML/
3See:http://www.w3.org/Consortium/
9
MembersExternaltoNIST
TetsuyaBaba, National Research LaboratoryofMetrology,Japan
Chris Bullough,ABBALSTOM Power, LeicesterUK
Fran Cvema, ASM, International
CharlesGibson, CenterforInformationand Numerical DataAnalysisand Synthesis (CINDAS)
SashaGurke, WilliamAndrewPublishing
Kohmei Halada, National Research InstituteforMetals, Japan
Gil Kaufman, AluminumAssociation, Inc.
Tom Kipp, MSC.Software
David Martin, IowaStateUniversity
John McCarthy, Lawrence BerkeleyNational Laboratory
ScottMcCormick, ESMSoftware
John Michopoulos, UnitedStates Naval Research Laboratory(USNRL)
Fred Moran, AtomicWeapons Establishment, UK
PeterMurray-Rust, Virtual School ofMolecularSciences, Nottingham University, UK
Crystal Newton, CenterforCompositeMaterials, UniversityofDelaware
FrankOlken, LawrenceBerkeleyNational Laboratory
Jon Phipps, WilliamAndrewPublishing
Adam C. Powell, Massachusetts InstituteofTechnology
Dennis Readey, ColoradoSchoolofMines
David Rose, Advanced Materialsand ProcessesTechnologyInformation Analysis Center(AMPTIAC)
MartinSmith, CenTORSoftwareCorporation
Michael Stoeckle, Ford MotorCompany
MikeSullentrup,The Boeing Company
NISTMembers
Ed Begley, ProjectLeader
Bill Boettinger, MetallurgyDivision
SandyDapkunas, Ceramics Division
Carol Handwerker, MetallurgyDivision
VickyKaren, Ceramics Division
UrsulaKattner, MetallurgyDivision
RonMunro, Ceramics Division
John Rumble, Standard Reference Data Program
Tom Siewert, MaterialsReliabilityDivision
Charles Sturrock, Standard Reference Data Program
ChristopherWhite, Building Materials Division
Table 1: MatMLWorkingGroup (1999-2001)
June 2001, theWorkshop on theTechnical and StrategicFuture ofMatML4 was hosted byNIST during
whichopendiscussions wereheld to tabulated specific issues thatrequired furthertechnicalrefinement of
the language. MatML 3.0 Schema(MatML 3.0) is an enhancementofMatML 2.0 that addresses the
technical issues identifiedduringthe workshop.
Approach
The specific revisionstoMatML2.0resulting inMatML 3.0include: porting the language specification
fromXMLDTD toXMLSchema; eliminatingredundantentry ofspecific types ofinformation;
overhaulingthe Unitscontentmodel; providingamechanism forencodingmeasurement uncertainty;
revising the contentmodel forTerms; modifying several elementcontent models to improve support for
encodingdata forcomposites; and addressing areported documentvalidation difficulty.
Schema
Fromthe outsetofthe MatML project, the working group suggested that the specification forthe language,
ultimately, oughtto beprepared usingthe XMLSchemaDefinitionLanguage5 (XML Schema) ratherthan
4 Sturrock,C.P.,Begley,E_.F_.,andKaufman,J.G.,"NISTIR6785MatML-MaterialsMarkupLanguageWorkshopReport," National
InstituteofStandardsandTechnology,Gaithersburg,MD,August2001.
5See:http://www.w3.org/2001/XMLSchema
3
XML DocumentType Definition (DTD). The reasons forusingXML Schemainclude obviating notable
shortcomings ofDTD's and, in anticipation ofMatML's acceptance testing phase, providing an improved
XML
language for software development. Schema, forexample, provides robustsupportfordatatyping,
including user-defined datatypes, whereas DTD's treat all datacontentessentially as text. Support fordata
types makes iteasierto define permissible datavalues and otherrestrictions, to validate data, and to convert
databetween differentdatatypes. All ofthese advantages are, among otherapplications, essential for
working with datafromdatabases. XML Schemas, furthermore, are written in XML whereas DTD's are
not. This is especially significant since it means that: XMLeditors and parsers can be used to editand
parse Schemafiles; Schemas can be manipulated using the XML DocumentObjectModel6 (DOM) (The
DOM
views the document as acollection ofobjects that can be manipulated, i.e., items can be added,
XML
deleted, and modified programmatically.); and Schemascan be transformed using stylesheet
language transformations7 (XSLT) (XSLT is used to transformand formatdocuments fordisplay.) Since
the MatMLdevelopmenteffort was initiated before the W3C had formally approved XML Schema as a
recommendation, itwas decided, forthe short term, to define MatML 1.0 and MatML 2.0 using DTD’s.
On 02 May 2001, theW3C approved XML Schema 1.0. Inresponse, MatMLhas been rewritten and the
new version conforms to the XML Schema Definition Language.
Redundancy
Sample instance documents encoded using MatML 2.0 illustrated thatdescriptions ofproperties,
measurementtechniques, data sources, and parameters could be repeated manytimes throughout a
document. This issue has been addressed by the introduction ofthe Metadataelement, which, in addition
to the previously mentioned descriptions, includes anothernewelement, SpecimenDetails, forencoding
descriptions ofspecimens.
Units
MatML 2.0 represented units as a simple string and permitted embedded HTMLtags. MatML 3.0 uses the
Units contentmodel developed by Dr. Edward J. ShayaofNASA Goddard Space FlightCenterforthe
extensible DataFormat (XDF) language version 0.178 This improved representation ofunits will permit
.
software developersto implement units conversion applications.
Uncertainty
Previous versions ofMatMLdid notprovide formeasurementuncertainty. MatML 3.0 includes anew
element, Uncertainty, forencoding this information and was constructed based upon the recommendations
ofDr. Ron Munro ofNIST's Ceramics Division (MSEL) and Dr. Raghu KackerofNIST's Mathematical
and Computational Sciences Division in the Information Technology Laboratory.
Glossary
The Terms elementinMatML 2.0 has been replaced by the Glossary elementinMatML 3.0, which uses a
™*
simplified contentmodel forencoding terms instead ofthe Virtual HyperGlossary1 9 markup language.
Composites
MatML 3.0 includes the revisions proposed by the MatML Composites Working Group. Thesechanges
includerecursion ofthe ComponentDetails element as well as new attributes on the Material element (id,
layers, local_frame_of_reference) and the ComponentDetails element (id).
6See:http://www.w3.org/DOM/
7See:http://www.w3.org/TR/xslt
8See:http://xml.gsfc.nasa.gov/DTD/XDF_017.dtd
9See:http://www.vhg.org.uk/home/index_ffame.html
4
Nesting
The MatML ASM-MSC DataExchange Focus Groupreporteddifficulties validating MatML 2.0instance
documents where multiple elementtuples ("tuple" is adataobjectcontainingtwo ormore dataelements)
were encoded within asingle element (Compound, PropertyDetails, etc.). Multiple element tuples have
beeneliminatedinMatML3.0 andhave beenreplacedby nested content models.
Results
Appendix Acontains the formal specification forMatMLVersion 3.0 Schema, includingdetailed
documentation ofeachelement's content model. The following discussionpresents ahigh-level overview
ofthe language specification.
MatML_Doc
Theroot elementforaMatMLdocument is named MatML_Doc. The MatML_Doc elementcontains one
ormore Material elements, each ofwhich describes a material andits properties.
Material
The informationcontained bythe Material element is compartmentalized into five majorelements:
1. BulkDetails element contains a descriptionofthe bulkmaterial;
2. ComponentDetails element contains adescriptionofeachcomponentofthe bulk material (useful
forcomplex materials systems such as composites or welds);
3. Metadataelementcontains descriptions ofdata found in the document;
4. Graphs elementencodes two dimensional graphics;
5. Glossaryelementcontains definitions ofterms found in the document.
BulkDetails
The BulkDetails element is composedofthe following elements, whichare fullydocumentedinAppendix
A:
• Name containsthe bulkmaterial's name;
• Classcontains the bulkmaterial's class;
• Subclass contains the bulk material's subclass;
• Specification contains the bulk material’s specification;
• Source contains the source ofthe bulk material;
• Formcontainsthe formofthe bulk material;
• ProcessingDetails contains adescription ofastep in the processing historyofthe bulkmaterial;
• Geometrycontains adescriptionofthe geometryofthe bulk material;
• Characterizationcontains the characterizationofthe bulkmaterial including the chemical formula,
chemicalcomposition, phase composition, anddimensional details;
• PropertyDatacontains datafora propertyofthe bulk material;
• Notescontains any additional informationconcerningthe bulkmaterial.
ComponentDetails
TheComponentDetails element iscomposedofthe following elements, which are fully documented in
Appendix A:
• Name contains the component’s name;
• Class contains the component’s class;
• Subclass contains the component’s subclass;
• Specificationcontains the component's specification;
• Source contains the source ofthe component;
• Formcontainsthe formofthe component;
5
• ProcessingDetails contains adescription ofastepinthe processing historyofthe component;
• Geometry contains adescriptionofthe geometryofthe component;
• Characterization contains the characterizationofthe component, including the chemical formula,
chemical composition, phase composition, anddimensional details;
• PropertyDatacontains datafora propertyofthe component;
• AssociationDetails contains adescription ofthe relationship ofthecomponentto another
component;
• Notes contains any additional information concerningthe component;
• ComponentDetails contains a description ofacomponent within the component.
Metadata
The Metadataelement contains descriptions ofthe data sources, properties, measurementtechniques,
specimens, and parameters encoded within the MatML document. The Metadataelementis composed of
the following elements, whichare fullydocumented in Appendix A;
• DataSourceDetails contains adescription ofadata source;
• PropertyDetails contains adescription ofaproperty;
• MeasurementTechniqueDetails contains adescription ofa measurementtechnique;
• SpecimenDetails contains adescription ofa specimen;
• ParameterDetails contains adescription ofaparameter.
Graphs
The Graphs element uses the W3C's Scalable VectorGraphics10 markup language (SVG) fordescribing
two dimensional graphics and allows forthree types ofgraphical objects: vectorgraphics shapes, images,
and text.
Glossary
The Glossary element contains terms, each ofwhichis encoded usingthe Termelement. The Term
elementiscomposedofthe followingelements, whichare fully describedin Appendix A:
• Name contains the term's name;
• Definition containsthe term's definition;
• Abbreviation contains the term's abbreviation(s);
• Synonymcontains the term's synonym(s);
• Notes contains any additional informationpertinentto the term.
Discussion
With the publication ofMatML 3.0, it is now possible to address othermain findings ofthe 2001 MatML
workshop. These include:
• A good set ofillustrations demonstratingthe powerandflexibilityofMatML
shouldbe establishedin orderto advance the widespread adoption ofMatML
(Appendix B);
• MatML mustbetestedthoroughly, involving individuals at various stages inthe
material development/application cyclerangingfrommaterials specialists who
select materials to designers responsible foraddressing load-carryingcapacity
and failure limits. In addition, the needs ofmaterials scientistsexploringthe
fundamental structure and properties ofmaterials, andofjournal publishers
disseminating materials information, must also be addressed;
10
See:http://www.w3.org/TR7SVG/
6