Hanging Messages: Using Context-Enhanced Messages For Just-In-Time Communication by Emily L. Chang Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment of the requirements for the degree of Master of Engineering in Electrical Engineering and Computer Science at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY May 2001 ® Massachusetts Institute of Technology 2001. All rights reserved. A u th or ....................................... Department of Elect rica pu ence May 17, 2001 C ertified by ......................... Pattie Maes Associate Professor, Media Arts and Sciences Thesis Supervisor A ccepted by ....................... r .... ........ ....... Arthur C. Smith Chairman, Department Committee on Graduate Students MASSACHUSETTS INS-TITUTE OF TECHNOLOGY JUL 112001 LIBRARIES BARKER 2 Hanging Messages: Using Context-Enhanced Messages For Just-In-Time Communication by Emily L. Chang Submitted to the Department of Electrical Engineering and Computer Science on May 17, 2001, in partial fulfillment of the requirements for the degree of Master of Engineering in Electrical Engineering and Computer Science Abstract Recent innovations in wireless and mobile computing have enabled the development of Just-In-Time communication channels using devices such as cell phones and handhelds. However, as with existing systems such as e-mail, there is a real danger that individuals will be overwhelmed by the speed and volume of information flow. The solution presented in this thesis is to locate an agent on each user's mobile wireless device, which will make use of information about the user to filter incoming communications. Specifically, the system uses contextual information, the current time and location of the recipient, in combination with user expressed preferences, to filter messages. Ideally, a user should never receive any message which is unsolicited or irrelevant to her current context. The complete implementation includes a central message server and any number of wire- less Internet-enabled, location-aware mobile devices, which may send and receive messages. Among the filtering mechanisms used by the agent are a precise hierarchical categorization for messages, user profiling by rules, and multiple location-based operational modes for each user. The end result is a Just-In-Time communication system which allows users to quickly receive relevant, time and location-sensitive messages. Thesis Supervisor: Pattie Maes Title: Associate Professor, Media Arts and Sciences 3 4 Acknowledgments I am grateful to my advisor, Pattie Maes, who was constantly available to provide advice, suggestions, ideas, and feedback, and kept my project from running off in strange directions. I also want to thank Jim Youll, Joanie Morris, Sybil Shearin, and the rest of the Agents, for being generous with their time and experience, and particularly for helping me out early in the year, when I was young and clueless. To my apartment-mates (both upstairs and downstairs), and especially to Danny Lai, thanks for keeping me sane. To Mom, Dad, Michelle, and Andrew, thanks for your continued love and support and for always being there for me. 5 6 Contents 1 Introduction 13 1.1 Just-In-Time M essaging ........ ..................... 13 1.2 Context-Enhanced M essages. ........... .............. 14 1.2.1 Time and Location of Delivery ..................... 14 1.3 Client-side Agent Filtering. ........................... 15 1.3.1 Categories. ................................ 16 1.4 Hanging M essages ................................ 16 1.5 Document Overview ............................... 17 2 Vision 19 2.1 Overview ..................................... 19 2.2 Scenarios of Use ................................. 20 2.2.1 Personal Reminders ........................... 20 2.2.2 Requests from Others ...... .................... 21 2.2.3 Promotional Use .............. ............... 21 2.2.4 Distributing Information ............... .......... 23 2.3 Research Focus ...... ............. .............. 23 2.3.1 Importance of Filtering .................... ..... 23 2.3.2 Overview of M echanisms . ............. ........... 24 3 Design and Implementation 27 3.1 System Architecture .................... ........... 27 3.1.1 Overview ... ......................... ..... 28 3.1.2 Server M odules ......................... ..... 29 3.1.3 Client M odules .............................. 30 3.1.4 Design Decisions .... ......................... 32 3.2 Filtering M echanisms .......... ..................... 32 3.2.1 M essage Categories ............. ............... 33 3.2.2 M odes and Locations ........................... 35 3.2.3 User Profiles ............................... 36 3.2.4 M essage M anagement ...... .................... 37 3.2.5 Summary ................................. 38 3.3 Implementation .................................. 38 3.3.1 Server ................................... 38 3.3.2 Client .................... ............... 39 3.3.3 Communication Protocols ........................ 40 7 4 Using Hanging Messages 43 4.1 Client Usage . ..... .... ..... .... ..... .... ..... .. 43 4.1.1 Starting a Session . .... .... ... .... .... ... .... 43 4.1.2 Composing M essages ... .... ..... .... .... .... ... 44 4.1.3 Incoming M essages .. .... .... .... ..... .... .... 44 4.1.4 Login Options . .... .... ... .... ... .... .... ... 45 4.1.5 M essage Visibility ... ..... .... .... .... ..... ... 46 4.1.6 M essage Retrieval Options. .... .... .... .... .... ... 47 4.1.7 Filtering Options . ..... ..... ..... ..... ..... ... 49 4.1.8 Help M anuals .... ...... ....... ...... ...... .. 53 4.2 Installation and Configuration. ..... ..... ...... ..... .... 54 4.2.1 Server .... ..... .... .... .... ..... .... .... 54 4.2.2 Client .. .... .... ..... .... .... .... ..... ... 55 5 Evaluation 57 5.1 Significant System Characteristics ..... ....... ....... .... 57 5.1.1 Connectivity and Bandwidth .. ..... ..... ..... ..... 57 5.1.2 Software Concerns .... ..... ..... ..... ..... .... 58 5.1.3 Configurability .. ...... ....... ...... ...... ... 59 5.1.4 User Privacy . ..... ..... ..... ..... ..... ..... 60 5.2 Usability .. ...... ..... ...... ..... ...... ..... ... 61 5.2.1 User Feedback ... ..... ..... ..... ..... ..... .. 61 5.2.2 Implementation Changes .. ....... ...... ...... ... 62 6 Related Work 65 6.1 Find-The-Nearest .... ..... ...... ..... ...... ..... .. 65 6.2 Location and Customization ...... ......... ......... ... 65 6.3 Location and Information ... ...... ..... ...... ..... ... 66 6.4 Location and Messaging . ...... ..... ..... ...... ..... 67 6.4.1 Locust Swarm . ..... ..... ..... ..... ..... .... 67 6.4.2 HaikuHaiku ... ..... ..... ..... ..... ..... .... 67 6.4.3 Geocorder . ..... .... .... ..... .... .... .... .. 67 6.4.4 comMotion .. .... ..... .... .... .... ..... .... 68 6.4.5 GeoNotes . .... .... ... .... .... ... .... ... ... 68 6.5 Just-In-Time Filtering .... .... ..... .... ..... .... .... 69 6.5.1 Pigeon . ............. ............ ......... 69 6.5.2 E-mail ..... ....... ...... ....... ...... .... 70 7 Concluding Remarks 71 7.1 Future Implementation .. ..... ...... ..... ...... ..... 71 7.1.1 M essage Modification ..................... ..... 71 7.1.2 M essage Reactivation .. ..... ..... ..... ..... .... 72 7.1.3 M ultiple Locations .... ..... ..... ..... ..... .... 72 7.1.4 Complex Filtering Rules . ...... ...... ....... ..... 72 7.1.5 Recognition Groups . ..... .... .... .... ..... .... 73 7.1.6 Agent Learning . .... ..... .... .... .... ..... ... 73 7.1.7 Encryption .... .... ..... .... .... .... .... ... 73 7.2 Conclusion ...... ..... ...... ..... ...... ..... ... 74 8 A Server: Class Dependencies 75 B Client: Class Dependencies 77 C Server Communication Protocol 79 9 10 List of Figures 2-1 A personal grocery list ........ ..................... 20 2-2 A request to run an errand .... .............. ......... 21 2-3 A special promotion ........ .............. ......... 22 2-4 Information about a construction site ......... ............ 23 2-5 Selecting a message attribute . ......... ......... ....... 24 2-6 Inserting a message value ............. .............. 24 2-7 The new rule is added to the profile ....... .............. 25 2-8 Known sender list .............. ................ .. 26 3-1 Primary interactions between client and server . .............. 29 3-2 Diagram of server architecture .............. ........... 30 3-3 Diagram of client architecture ........ ............. .... 31 3-4 Diagram of category hierarchy ..... ......... ......... .. 34 3-5 Editing profile rules for the current mode ............ ....... 36 3-6 Editing profile rules for all modes ... ............. ....... 37 4-1 Logging into the client ......... ............. ....... 43 4-2 Composing a new message .... ......... ......... ..... 44 4-3 An incoming message ....... ......... ......... ..... 45 4-4 The user can choose a different message server .... ............ 45 4-5 Location can be manually set or automatically determined .. ....... 46 4-6 Menu options ...... ......... ......... ......... .. 47 4-7 Users can assign nicknames to locations ........ ......... ... 47 4-8 Users can change their current mode of operation .. ......... ... 48 4-9 Users can set the search radius for messages ....... .......... 49 4-10 Changing filtering options ..... ......... ......... ..... 49 4-11 Editing personal profiles ....................... ..... 50 4-12 Selecting a message attribute ........... .............. 50 4-13 Inserting a message value ... ......... ......... ....... 51