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

materials-orientedandeasyto learn; and 1350
metakbo MatML's syntax mustbe extensible to aluminum alloy
accommodate both alternative andunanticipated ASTM B230
forms ofmaterials data andtheirrepresentation. H18
From“PropertiesofAluminumAlloys-Tensile, Creep, and Perhapsthe best wayto describe MatMLisby Fatigue DataatHigh and LowTemperatures.”
Axial-Stress Fatigue Strength (ksi)
example andincontrast to HTML. Materials

propertydatadistributedonthe WorldWide Web indocumentsusing hypertext markup language (HTML) present two problems for

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 serious drawbackto those who wish to automate the processingofthe data 1350 containedin those documents. metal aluminumalloy To address this problem, the ASTM B230 Extensible Markup Language' (XML) was developed and H18 released bythe World Wide Web Consortium1 (W3C), an 23,17,15 international group of approximately 500 member organizations dedicatedto developing commonprotocols thatpromote the evolution of “PropertiesofAluminumAlloys-Tensile, the Web andensure its Creep, and Fatigue Dataat High and Low interoperability. Temperatures.” XML enables communities, such as materials scientists and Axial-Stress Fatigue Strength engineersinthe case of cllnits name=”ksi” Description=”kippersquare inch”> MatML, to define theirown kip

inch domain-specific tags and document structure, i.e., they can create theirown languages

fordatamanagement and exchange that, in turn, permit efficientparsing and Fig. 2: Aluminum alloy data inMatML interpretationofthose data via software. The descriptive nature ofthe MatMLtags, such as , , and 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

MatML version 3.0 schema

Similar MatML version 3.0 schema