1. A web based tool for estimation of Gage R&R and Measurement Uncertainty Siva Venkatachalam & Dr. Jay Raja Center for Precision Metrology The University of North Carolina at Charlotte Charlotte, NC 28223 NSCLI Annual Workshop & Symposium August 20 th, 2003

2. 2August 20, 2003NCSLI Annual Workshop & Symposium Outline Introduction Design features Database functionality Scenario of usage Gage R&R system (overview) Conclusions

3. 3August 20, 2003NCSLI Annual Workshop & Symposium Surface and Form Metrology Group

4. 4August 20, 2003NCSLI Annual Workshop & Symposium Introduction Uncertainty is a parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand.* * The term measurand is defined as ‘a particular quantity subject to measurement.’ Source: ISO 14253 – 1

5. 5August 20, 2003NCSLI Annual Workshop & Symposium Uncertainty in Conformance Specification Source: ISO 14253 – 1

6. 6August 20, 2003NCSLI Annual Workshop & Symposium Why do we need software systems? Everything, nowadays is being done with the help of computers and associated software systems. Too many types of measurements from the macro to the micro scale. It is lot easier to keep track of the different environments and the types of gages that are used for making the measurements.

7. 7August 20, 2003NCSLI Annual Workshop & Symposium Why internet based systems? Internet based systems can be accessed remotely with the help of a browser. This helps in enhancing globalization. It also aids in the collaborative efforts between people in different parts of the world. Most of the hassles due to a conventional system can be avoided.

8. 8August 20, 2003NCSLI Annual Workshop & Symposium Measurement uncertainty software system Three – tier architecture system Implementation based on GUM Client: Web browser, HTML Server: Java Servlets Database: Oracle (PL/SQL) Three – tier architecture system

9. 9August 20, 2003NCSLI Annual Workshop & Symposium Software Design – UML The unified software development approach was used in the development of this software system. This approach is based on Unified Modeling Language (UML) which is the most widely used modeling tool in today’s software industry. UML has been divided into various phases and workflows to aid in the easy and efficient development of the software system. Workflows: Requirements, Analysis, Design, Implementation and Testing. Phases: Inception, Elaboration, Construction and Transition.

10. 10August 20, 2003NCSLI Annual Workshop & Symposium Workflows and Phases

11. 11August 20, 2003NCSLI Annual Workshop & Symposium Requirements specification Requirement specification involves defining use cases required for a complete software system. A uses case is a piece of functionality in the system that gives the user a result of value.

12. 12August 20, 2003NCSLI Annual Workshop & Symposium Analysis of requirements Analysis involves bringing out the details for each of the identified use cases. Identify target user and classes involved. (A class in Java comprises of attributes, functions and procedures)

13. 13August 20, 2003NCSLI Annual Workshop & Symposium Design model Metrologist package for the uncertainty system

14. 14August 20, 2003NCSLI Annual Workshop & Symposium Database design Requirement analysis Done by querying a set of end-users (target audience) Done by querying a set of end-users (target audience) Entity – Relationship Model Define entities and attributes Define entities and attributes Entities are real world ‘things’ capable of independent existence. Attributes are properties that describe the entity. Entities are real world ‘things’ capable of independent existence. Attributes are properties that describe the entity. Relational schema A relational schema is made up of a relation and a set of attributes that describe the relation. A relational schema is made up of a relation and a set of attributes that describe the relation. Build the database PL/SQL (Oracle) is used to build the physical model of the database. PL/SQL (Oracle) is used to build the physical model of the database.

15. 15August 20, 2003NCSLI Annual Workshop & Symposium Entity – Relationship (ER) model

16. 16August 20, 2003NCSLI Annual Workshop & Symposium Implementation and Testing Implementation Client side Client side Hypertext Markup Language (HTML) for user interfaces (UIs) Java Server Pages (JSP) for dynamic content Java Script for authentication Server side: Java Servlets Server side: Java Servlets Database: Oracle (PL/SQL) Database: Oracle (PL/SQL)Testing Installation test: Verifies if the system can be installed and operated efficiently on the customer’s platform. Installation test: Verifies if the system can be installed and operated efficiently on the customer’s platform. Configuration test: Checks for software compatibility with different network configurations Configuration test: Checks for software compatibility with different network configurations Negative tests: Cause the system to fail Negative tests: Cause the system to fail Stress tests: Problems in the system due to insufficient resources. Stress tests: Problems in the system due to insufficient resources.

17. 17August 20, 2003NCSLI Annual Workshop & Symposium Scenario of Usage User Registration http://sfmg.uncc.edu:8080/uncertainty/jsp/login.jsp

18. 18August 20, 2003NCSLI Annual Workshop & Symposium Sign In to the system

19. 19August 20, 2003NCSLI Annual Workshop & Symposium Main Screen

20. 20August 20, 2003NCSLI Annual Workshop & Symposium Gage Class – Micrometer

21. 21August 20, 2003NCSLI Annual Workshop & Symposium Standard Uncertainty Estimation

22. 22August 20, 2003NCSLI Annual Workshop & Symposium Type A evaluation

23. 23August 20, 2003NCSLI Annual Workshop & Symposium Type B evaluation

24. 24August 20, 2003NCSLI Annual Workshop & Symposium Expanded Uncertainty

25. 25August 20, 2003NCSLI Annual Workshop & Symposium Summary of results

26. 26August 20, 2003NCSLI Annual Workshop & Symposium Measurement history

27. 27August 20, 2003NCSLI Annual Workshop & Symposium Update user profile

28. 28August 20, 2003NCSLI Annual Workshop & Symposium Edit measurement parameters

29. 29August 20, 2003NCSLI Annual Workshop & Symposium Edit uncertainty information

30. 30August 20, 2003NCSLI Annual Workshop & Symposium Gage R&R system The system is a two-tier architecture designed using HTML and JSP as the front-end and Java Servlets as the back-end. The features in the system include Choice of trials(2 or 3) Choice of trials(2 or 3) Choice of number of operators(2 or 3) Choice of number of operators(2 or 3) Choice of number of parts(5 or 10) Choice of number of parts(5 or 10) Computations for average and range method Computations for average and range method Computations for ANOVA method Computations for ANOVA method Comparison of the two methods Comparison of the two methods http://servlets.uncc.edu/~sivenkat/gageRR/jsp/main.jsp

31. 31August 20, 2003NCSLI Annual Workshop & Symposium Main Screen

32. 32August 20, 2003NCSLI Annual Workshop & Symposium Data sheet

33. 33August 20, 2003NCSLI Annual Workshop & Symposium Average & Range Method

34. 34August 20, 2003NCSLI Annual Workshop & Symposium ANOVA Method

35. 35August 20, 2003NCSLI Annual Workshop & Symposium Results

36. 36August 20, 2003NCSLI Annual Workshop & Symposium Comparison between the two methods

37. 37August 20, 2003NCSLI Annual Workshop & Symposium Conclusions The internet based software is the first of its kind to be developed. Features User friendly and simple to use User friendly and simple to use Efficient uncertainty budgets and Gage R&R computations. Efficient uncertainty budgets and Gage R&R computations. Accessed from an internet browser remotely at any point of time. Accessed from an internet browser remotely at any point of time. No disk space and installation hassles. No disk space and installation hassles.

38. 38August 20, 2003NCSLI Annual Workshop & Symposium Questions ?