Patrik Werle Gregory D. Abowd The Future Computing Environments (FCE) Group, Georgia Institute of Technology Ubiquitous Computing: Research Themes and Open Issues from an Applications Perspective GVU Technical Report GIT-GVU December Software Design Issues for Ubiquitous Computing Invited paper to the IEEE CS Annual Workshop on VLSI: System Level Design (IWV '98), Orlando, FL, April, 1998

Patrik Werle Three Emergent Research Themes 1. Automated capture, integration and access 2. Context awareness 3. Ubiquitous software services

Patrik Werle Ubiquitous Computing Technology ”… any computing technology that permits human interaction away from a single workstation”.

Patrik Werle Automated Capture, Integration and Access PROBLEM: A lot of time is spent on listening to and recording the events that surround us SOLUTION: CIA automatically records, we relate, summarize and interpret EXAMPLE: (”Classroom 2000”) Smartboards, personal pen-based interfaces, digital AV, WWW

Patrik Werle Granularity of integration e.g. sound links, any slide vs. any gesture Supporting revision during access i.e. upon reflection Supporting networked interaction e.g. ”copy” teacher’s notes, anonymous feedback Automated CIA (cont.) Open Research Issues

Patrik Werle Automated CIA (cont.) Software Challenges Interaction transparency e.g. the room’s presentation software knows the room’s schedule. Integration e.g. linking and synchronize different streams Access e.g. visualise multiple streams

Patrik Werle Context-aware Computing PROBLEM: Applications on, for example PDAs, are deigned for desktops, or very simple – none take eg. position into account SOLUTION: Use e.g. GPS receivers to provide position info EXAMPLE: (”CYBERGUIDE”) Automatically update a tourist guide according to user’s position

Patrik Werle Context-aware Computing (cont.) Open research issues Providing ubiquitous positioning and communication e.g. GPS only available outdoor and to communicate feedback to the teacher There is more to context than position e.g who is around, historical info, time Use of personalized vision and voice technology HCI issues

Patrik Werle Context-aware Computing (cont.) Software Challenges 1. Collect information 2. Analyse information 3. Perform some action 4. Repeat with some adaptation Challenge: To create a general and scalable context inferencing engine

Patrik Werle Ubiquitous Software Services PROBLEM: The service should “find the user” SOLUTION: Services should be available on any device (service integration, transformation, scalability etc.) EXAMPLE: A messaging service that choose communication technology (phone, , fax etc.) depending on e.g. urgency

Patrik Werle Ubiquitous SW Services (cont.) Open Research Issues Scaleable interfaces (E.G. WWW, Java vm, phone to access the calendar) Ubiquity should not be annoying (the user may, for example, never be able to hide from the interface)

Patrik Werle Mark Weiser Xerox Palo Alto Research Center Some Computer Science Issues in Ubiquitous Computing Communications of the ACM, July (reprinted as "Ubiquitous Computing". Nikkei Electronics; December 6, 1993; pp )

Patrik Werle Three Size of Computers Tab e.g. a display and/or a touchpad (”hundreds of”) Pad notebook-sized computers (”tens of”) Board e.g. wall-sized interactive surface (”one or two”)

Patrik Werle Issues of Hardware Components Low power Wireless Pens

Patrik Werle Network Protocols Wireless media access Wide-bandwidth range Real-time capabilities Packet routing

Patrik Werle Interaction Substrates Touch-printing Location independent interaction Moving applications (e.g. ”window migration”) Bandwidth

Patrik Werle Applications ”…of course the whole point of ubiquitous computing”. Locating people (e.g. Automatic phone forwarding, locating an individual for a meeting, watching general activity in a building) Shared tools (e.g. shared drawing)

Patrik Werle Privacy of Location Store/access from where? For how long time? Social issues must be considerated!

Patrik Werle Computational Methods Cache sharing The Cache Sharing Problem. A problem instance is given by a sequence of page requests. Pages are of two types, U and C (for uncompressed and compressed), and each page is either IN or OUT. A request is served by changing the requested page to IN if it is currently OUT. Initially all pages are OUT. The cost to change a type-U (type-C) page from OUT to IN is CU (respectively, CC). When a requested page is OUT, we say that the algorithm missed. Removing a page from memory is free. Lower Bound Theorem: No deterministic, on-line algorithm for cache sharing can be c-competitive for c < MAX (1+CU/(CU+CC), 1+CC/(CU+CC)) This lower bound for c ranges from 1.5 to 2, and no on-line algorithm can approach closer to the optimum than this factor.