On Integrating Physical Objects with the Internet Niranjan Kundapur Bachelor of Technology, Mechanical Engineering (1998) Indian Institute of Technology, Madras Submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY September 2000 © Massachusetts Institute of Technology, 2000. All Rights Reserved. Author ................................ ............ Department of Mechanical Engineering June 30, 2000 Certified by ...... Professor Kai-Yeung 'Sunny' Siu Associate Professor of Mechanical Engineering Thesis Supervisor C ertified by .................................. 7 ................ ............................................. Professor Sanjay E Sarma Associate Professor of Mechanical Engineering Thesis Supervisor A ccepted by ..................................... Professor Am A Sonin Chairman, Department Committee on Graduate Students MASSACHUSETTS INSTITUTE OF TECHNOLOGY SFP 2 0 7000 LIBRARIES BARKER M.I.T. LIBRARIES - BARKER 2 On Integrating Physical Objects with the Internet by Niranjan Kundapur Submitted to the Department of Mechanical Engineering on June 30, 2000 in partial fulfillment of the requirements for the degree of Master of Science Abstract This thesis examines key areas of research involved in integrating information, which pertains to physical objects, with the Internet, and delivering this information anytime anywhere. We broadly classify the research areas into three layers: the Physical Object Layer, the Information Storage Layer, and the Wide Area Access Layer. We discuss background information relevant to each of the layers, such as Universal Product Code (UPC), JiniTM, Bluetooth, eXtensible Markup Lan- guage (XML), XML Query Language (XQL), Wireless Application Protocol (WAP), and Wireless Markup Language (WML). The Electronic Product Code (ePC), which was developed by David Brock of MIT, is a unique identification number for each physical object. It serves as a numerical reference to information, which pertains to a physical object, on the Internet. This number is embedded in radio frequency (RF) Tags attached to an object. An RF Tag Reader can read the embedded ePC when the Tag is within a certain distance of the Reader. In the Physical Object Layer, our work describes how the ePC complements Resource Discovery protocols, such as JiniTM and Bluetooth, in Local Area Net- works of Devices, such as RF Tag Readers. Since information regarding the movement of physical objects is critical in many applications, we propose the RSVP protocol among RF Tag Readers, to track tagged physical objects. We also compare the different numbering schemes of the ePC. The information, which is referenced by the ePC of a physical object, is in Physical Markup Lan- guage (PML) format. This format serves as the lingua franca for describing physical objects. In the Information Storage Layer, we develop insight into the data model of XML. Since PML is based on XML, this insight will be useful during the ongoing research to define PML. We discuss issues of implementation of the data model and issues of cooperation in the choice of PML elements. Our implementation work in this layer is the use of XML and XQL along with JiniTM to develop a cli- ent-server software application, which tracks physical objects moving in a remote location. The Wide Area Access Layer comprises various application platforms that deliver information on physical objects to mobile users. We describe our application that allows a user to access, using her WAP-enabled cell phone, data from remote sensors. We describe our software application, which automatically converts PML to WML format for display on mobile devices. Thesis Supervisor: Kai-Yeung 'Sunny' Siu Title: Associate Professor Thesis Supervisor: Sanjay E Sarma Title: Associate Professor Acknowledgement I thank Prof. Sanjay Sarrna for introducing me to the Auto-ID Center. I also thank him for his general advice and friendliness. I am grateful to Joe Foley and Jocelyn 'Bink' Tait for giving me valuable suggestions during my research. Thanks to Bink for suggesting significant improvements while proof-reading my thesis. Thanks to Joe Foley and Aparna Chennapragada for proof-reading parts of my thesis. Thanks to Yogesh Joshi for being a pal at the lab. Thanks to David Rodriguera for his help in taking care of my administrative work. Thanks to Mahadevan Balasubramaniam, Elmer Lee, Stephen Ho. Paula Valdivia y Alvarado, and Edmund Golaski of Rapid Autonomous Machining Laboratory for advice and the good times. Thanks to the Pakodas for making life at Cambridge a lot of fun. Thanks to Jeff Vanness, Michael Padilla, and Dave Steare, all of whom made my first year at MIT's Tang Hall memorable. Thanks to Trupti, Amma, Annu, and Shweta for love and support. Niranjan Kundapur 5 6 Table of Contents Chapter 1: Introduction ---------------------------------------- 11 1.1 Organization of Subsequent Chapters -------------------------------- 12 Chapter 2 : Physical Object Layer --------------------------------- -17 2.1 The ePC as the Future Product Identification Code - ------- ------- ------- - 17 2.1.1 The Current Bar Code ------ ------- ------- ------ ------- ----- 17 2.1.2 The ePC in Comparison with the UPC bar code ------- ------ ------- - 18 2.2 The ePC as Device ID: Local Area Networking of Physical Objects ------------ 21 2.2.1 Resource Discovery: JiniTM ------------------------------------- 21 2.2.2 Bluetooth --------------------------------------------------- 22 2.3 The RSVP Proposal --------------------------- ----- 22 2.3.1 The Problem ---------------------------- ----- 22 2.3.2 A Solution in the Style of TCP ---------------- ----- 22 2.3.3 Assumptions ---------------------------- - - -- -----23 2.3.4 Sender Function --------------------------- ----- 24 2.3.5 Receiver Function ------------------------ - - -- -----24 2.3.6 Boundary Conditions ---------------------- - - - -----25 2.3.7 Data-structures and Algorithms ---------------- ----- 25 2.3.8 Solution of the Original Problem- -------------- - - ------25 Chapter 3 : Information Storage and Retrieval Layer --- --- -27 3.1 eXtensible Markup Language -------------------------------- - - -- -----27 3.1.1 XML in Brief --------------------------------------- ----- 28 3.2 XML data format ----------------------------------------- - - ----- 29 3.2.1 Data, Meta-Data, Relationships, and Documents --------------- ----- 29 3.2.2 Data Models ---------------------------------------- - - - - - 31 3.2.3 Creating XML documents from Entity-Relationship data model ----- - - - - - 33 3.2.4 Logical Structure of XML ------------------------------- - - - - - 36 3.2.5 XML Text Parsers -------------------------------------- ----- 37 3.2.6 Implementation Structure in XML ------- ------------------ ----- 37 3.2.7 Practical Issue of Collaboration ------------------------------ - - -- -----39 3.2.8 Final Remarks on XML --------------------------------- - - -- -----39 3.2.9 Other Members of XML Family ---------------------------- --- -- 40 3.2.10 XQL ----------------------------------------------- - -------41 3.3 PMLandONS ------------------------------------------ ----- 42 3.4 Applications: Inventory Tracking Software Module ----------------- ------ 43 Chapter 4 : Wide Area Access Layer ------------------------------- 45 4.1 Technologies Used ------------------------------------------------ 45 4.1.1 Wireless Application Protocol ------------------------------------ 45 4.1.2 Wireless Markup Language ---------------------------------- 46 4.1.3 WMLScript Language -------------------------------------- 47 7 4.2 Design by Synthesis of Technologies --- -------------- 48 4.2.1 PML-to-WML Conversion ------- -------------- 48 4.2.2 Server and Servlets ------------- -------------- 50 4.2.3 BASIC Stamp and DS1620 ------- -------------- 50 4.2.4 WAP Gateway ---------------- -------------- 51 4.3 Lessons Learned and Applications ------ -------------- 52 Chapter 5 : Conclusions --------------- ------------- 55 Appendix A: Acronyms ---------------- ------------- 57 Appendix B : Generations of Database Systems ------------- 59 Appendix C: Use of XML/XQL ---------- ------------- 61 Appendix D : ServIet program ------------ ------------- 63 References ------------------------- ------------- 65 8 List of Figures Figure 1.I: Logical Layers of Abstraction of Research --- ------------ ----------- 13 Figure 2.1: RSVP Proposal -- ------------ ------------- ------------ - - - - -- 23 Figure 3.1: Tree structure of the environment of physical objects -------- ----------- 27 Figure 3.2: Data, information, and knowledge ---- ------------ ------------ ---- 28 Figure 3.3: Integrating data into document-centric documents ------------ --------- 31 Figure 3.4: Levels of data abstraction and Migration of complexity -- -------------- -- 31 Figure 3.5: E-R semantic data model to construct a bank schema ---------- --------- 33 Figure 3.6: Relational data model of bank schema --- ------------ ------------- - 33 Figure 3.7: Object-oriented data model of bank schema- -------------------------- 34 Figure 3.8: XML text file to represent the E-R data model ------------------------ 34 Figure 3.9: Object-oriented data model of bank schema, with inheritance -------------- 35 Figure 3.10: XML text file to represent the inheritance -------------------------- 35 Figure 3.11: XML file ----------------------------------------------------- 36 Figure 3.12: DOM representation of the XML file in Figure 3.11 --- -------