1 Augmenting MatML with Heat Treating Semantics Aparna Varde, Elke Rundensteiner, Murali Mani Mohammed Maniruzzaman and Richard D. Sisson Jr. Worcester Polytechnic Institute, Worcester, MA, USA -This work is supported by the Center for Heat Treating Excellence (CHTE) and its member companies and by the Department of Energy – Office of Industrial Technology (DOE-OIT) Award Number DE-FC D14197 Conference: ASM Materials Solutions, Oct 2004, Columbus, OH, USA Symposium: Developments in Web-Based Material Property Databases

2Introduction Domain Specific Markup Language: –Medium of communication for domain users. –Follows XML syntax. –Encompasses domain semantics. MatML: –Materials Science Markup Language. –XML for Materials Property Data. –Developed by NIST (National Institute of Stds. & Technology). Need for Extension: –MatML tags generic to Materials Science. –Desirable to incorporate the semantics of Heat Treating. –Extension proposed to MatML.

3 Heat Treating Involves controlled heating & cooling of materials to achieve desired mechanical & thermal properties. Quenching or rapid cooling: important step in heat treating. Quenchant: cooling medium. Part: material being cooled. Conditions: Temperature, Agitation etc. Quenching Setup at CHTE, WPI

4 MatML: Materials Science Markup Language One common exchange format for Materials data. Standard developed by NIST. Follows XML syntax. Enhances interpretability of data. Allows extensibility.

5 MatML Structure Root of schema “MatML_Doc”. Has one or more instances of “Material” element. Each has the foll. elements with sub-elements & attributes. 1.Bulk Details 2.Component Details 3.Metadata 4.Graphs 5.Glossary …………… ……………... ………………….

6 Data Storage using MatML Tags describe entities in Materials Science. Nesting describes relationships between entities. Semantics of data represented. Generic to Materials Science domain.

7 Motivation for Extension Entities in Quenching Process. –Quenchant, Part Surface, Quenching Conditions. These have attributes or properties. –e.g. Viscosity is an attribute of Quenchant. MatML schema not sufficient to store data on these. Hence the need to capture the semantics of Heat Treating / Quenching through extension.

8 Issues in Extending Domain Specific Markup Languages Representing domain semantics: Data models. Identifying needs of potential users: Domain expert interviews. Ontological considerations: E.g., synonyms. Designing the schema: XML constraints etc. Revising the schema: Based on critical reviews.

9 Modeling based on Semantics

10 Interviews: Needs identified Some data in quenching has to be stored in conjunction with basic materials information. Example: Consider a part undergoing quenching. –Material properties of part, e.g., Component Details. –Quenching process parameters, e.g., Part Surface. Hence the proposal for a “Quenching” element to be part of a MatML document, at the same level as the “Material” element. Note: Storage efficiency is the reason for extending MatML rather than developing a new “QuenchML”.

11 Ontology determined after Interviews Components of the ontology: –Quenching: the process of rapid cooling. –Quenchant: cooling medium (oil, water, gas etc.) –PartSurface: material undergoing rapid cooling. –Manufacturing: details such as stamping and welding. –QuenchConditions: agitation, temperature etc. –Results: e.g., cooling rate, distortion, heat transfer coefficient. –Graphs: cooling curves, cooling rate curves, heat transfer curves. Synonyms: –Several terms mean the same, e.g., Part, Probe, Work-piece all refer to one entity. Design ontology accordingly.

12 Schema: High Level Tag Set

13 Schema: Placement of Element Within “MatML_Doc” in MatML schema. Same level as the “Materials” element. This enables cross- referencing between “Quenching” and “Material” elements.

14 Schema: Interpretability of Data Schema: Interpretability of Data Understanding meaning of stored data: –With reference to context, –Without other documentation. Domain experts’ input crucial: –To decide how they want users to interpret data. Examples: –Cooling Rate: stored specifically at different locations. –Cooling Uniformity: general inference about the experiment. –Quenchant, part and conditions details should be stored before the results and graphs.

15 Detailed Schema: Partial Snapshot

16 XML Schema Constraints Sequence constraint: to declare a list of elements in order, e.g., ………………. ….. ……………… Disjunction constraint: to declare mutually exclusive elements, e.g., : …………………….

17 XML Schema Constraints (Contd.) Key constraint: to declare a primary key on an element or attribute, i.e., it must have unique values & cannot have null values, e.g., ………………………………. Occurrence constraint: to declare the minimum and maximum occurrences of an element., e.g., …………….. ……………..

18 XQuery for Retrieval of Data Schema designed to facilitate retrieval using XQuery. Issues: –XQuery is case-sensitive. Encourage users to store data in a case- sensitive manner to ensure correct retrieval. –Introduce additional tags if needed to assist querying and provide good readability, by anticipating typical user queries. ……..

19Conclusions “Quenching Element” proposed at CHTE as an extension to MatML, the Materials Science Markup Language (developed by NIST). Ontology and schema developed. Schema revision ongoing based on discussions with domain experts and standards bodies (NIST). Issues in extending domain-specific markup languages considered. More issues may emerge. Propose to incorporate this as a standard within the original MatML, to include Heat Treating semantics. Useful application of XML in the Heat Treating domain.