1 Pervasive & Ubiquitous Computing Hao Chu ( 朱浩華 ) Lecture #2 3/1/2004

2 Reading list Still working on it –Indoor localization –Embedding computing into (everyday) objects –Interactions –Ubiquitous healthcare –Security and privacy protection –Skip systems and sensor networks & shorten the overview

3 Project Project idea & scenario (week 5, 3/22/2005) Project proposal (week 9, 4/26/2005) Proposal progress (week 13, 5/24/2005) Final project presentation (week 16, 6/13/2005)

4 Course Wiki Add your WhoIsWho Add paper review (next week) Select papers

5 History Mark Weiser. "The Computer for the 21th Century." Scientific American, September Mark Weiser. "Some computer science issues in ubiquitous computing." Communications of the ACM, 36(7):75-85, July Mark Weiser, John S. Brown. "The Coming Age of Calm Technology." M. Satyanarayanan. "Fundamental Challenges in Mobile Computing." Fifteenth ACM Symposium on Principles of Distributed Computing, May M. Satyanarayanan. "Pervasive Computing: Vision and Challenges." IEEE Personal Communications, August, 2001.

6 M. Weiser. “The Computer for the 21th Century", Scientific American, September 1991.

7 Two Key Points Ubiquitous computing = computing integrated with physical environment –Computing being everywhere, yet people do not take notice of them –Computing becoming disappearing and invisible Location and scale are important. –Adapt their behavior intelligently without AI: call forwarding, follow-me display, reminder, good substitute for computer vision, etc. –Scale suitable to different tasks (heterogeneous systems and networks)

8 Examples of Disappearing Technologies Writing Electric Motors They are everywhere (embedding & hidden into physical objects), yet invisible. When a technology matures, they disappear! –Maturity = cheap, small, widely applicable, good usability, …

9 Why Good Technology Is Invisible? Good technology stays out of the way of task –Like a good pencil stays out of the way of the writing Bad technology draws attention to itself: –Like a broken, or skipping, or dull pencil Computers are mostly not invisible –They dominate interaction with them. Ubicomp is about making computers invisible.

10 Ubicomp vs. Virtual Reality Should we live in virtual computing world? Or should computing come out and live in our physical world? VR simulates physical world & puts people inside virtual computing world. Ubicomp is about bringing computing to people’s physical world. –Computing Embed into everyday objects (intelligent objects) –Integrate with social activities (social computing)

11 Ubicomp vs. Multimedia Multimedia grabs user attention for entertainment purpose. Ubicomp reduces user distraction, allowing people to focus on tasks. –Alternative output display on periphery of user attention: (ambient display)

12 Ubicomp Components Computing embedded and enhancing physical objects Ubicomp = sensors + processors + networking sensors + SW systems & middleware –Example: Intelligent Transportation System (foreview mirror)

13 PARC Ubicomp Work (1991) Focus on devices that transmit & display information. Device scale targets different tasks. –Consider three sizes: tabs, pads, boards.

14 Tabs Inch-scale Ubicomp devices –Post-It notes Carried around by a person Hundreds in a room –Credit cards, ID cards –Remote controllers –Badges –Tags / Labels (RFID) –Locating system (tags as library catalogs) –Animate static physical objects (active calendar, active map)

15 Pads Foot-scale Ubicomp devices –A sheet of paper / tablet PC Tens in a room –Like scrap papers that can be grabbed and used anywhere, no unique ID. Like windows in Apple Macintosh, but can spread them out on a real desk.

16 Boards Yard-scale Ubicomp device One in a room White board with e-chalk –Shared white board with remote participants Video screen Electronic Bookcases

17 Hardware Challenges (1991) High resolution flat panel display (cheap) High speed processor High capability storage High bandwidth wireless Network Lower power consumption How well do today’s HW technologies meet these challenges?

18 Software Challenges (1991) Dynamic configuration of HW/SW in ubicomp environments (dynamic systems) Application migration across heterogeneous ubicomp environments Transparent linking of wired and wireless networks (heterogeneous networks) How well do today’s SW technologies meet these challenges?

19 Sal Scenario Proactively brew coffee informed by alarm clock Electronic Trails of neighbor coming and going Automatic recording pen Paper display (e-ink) locates garbage door opener (RFID & object reminder) Window tells weather (ambient display) Intelligent car navigation (location-based services) Share location, tabs & pads with Joe (CSCW) Gesture to project blinking tab to projector (multi-model UI) Memory augmentation on meeting with Mary (lifelog)

20 Privacy Hundreds and thousands of invisible computers sensing and watching people Ubiquitous camera recording

21 Is Weiser really Wise? What is the problem that he wants to solve? What is his proposed solution? Any problems with the proposed solution? Invisibility & Intelligence vs. privacy –RFID in supermarket –Hidden security camera Invisible vs. transparent –Diagnose problems

22 M. Weiser. “Some computer science issues in ubiquitous computing.”Communications of the ACM, 36(7):75-85, July 1993.

23 Key Point Based on their PARC experiments with tabs, pads, and boards, this paper tries to define some ubicomp challenges and where ubicomp is going.

24 Ubicomp as Experimental CS Construct working prototype Evaluate working prototype in everyday use Find out real vs. imaginary issues

25 Hardware Issues Power consumption: impossible to change batteries to many ubicomp devices frequently. Balance of HW/SW feature: display, network, processing, memory, storage capability, multitasking, etc. Ease of expansion & modification (integration vs. modular design)

26 Network Issues Wireless Media Access (802.11, Bluetooth, Cellular Networks) Quality of Services (RSVP, etc) Ubicomp devices changing network attachment (Mobile IP)

27 UI Issues Multi-modal UI –Handprinting recognition –Voice recognition Display migration (follow-me display)

28 Application Issues “Applications are of course the whole point of ubiquitous computing”. Locating people (active badges) –Automated call forwarding –Tracking down people for meeting –Watching general activity in a building (feel in touch with surrounding environments) Shared drawing in virtual meeting –Scalability to 5000 peoples (multicast for bandwidth efficiency)

29 Location Privacy Centralized location database as one possible solution, but not scalable, vulnerable to single point of attack, one break-in reveals all. Move toward more distributed approach.

30 Computational Method Issue Due to unpredictable network to ubicomp devices, (file) caching can be used to improve performance.

31 Discussion Open ….

32 M. Weiser, J. S. Brown. "The Coming Age of Calm Technology." 1996.

33 Key Points Why the need for calm technology? –Computers everywhere –Pay attention in order to use them –Information overloading Solution for design of ubicomp technology –Place information in periphery of user attention –But allow fast & easy moving to center

34

35 Computing Trends These trends are results of computing getting smaller, faster, and cheaper. Mainframe Era: many people sharing a computer. PC Era: one computer per person Internet Era: (interconnecting PCs) Ubicomp Era: –many computers (everyday objects) sharing one person –interconnecting everyday objects

36 Calm Technology Calm and uncalm technology differs how to engage our attention. –Divide our attention into two parts: periphery and center. Periphery is informing without overburdening –While driving a car, center = roads and radio, periphery = engine noise Calm technology can move easily & quickly between periphery and center. Calm requires good design affordance (visual clue to the function of an object)

37 Three Signs of Calm Technology Move easily from center to periphery and back Enhance “periphery reach” (more details in the periphery) –Video vs. voice conferencing Good information visualization

38 Examples of Calm Technology Inner Office Windows –Extend periphery to what are going on the hallway –E.g., notice lunch gathering, meeting, but not distracting to work In comparison to open cubicles with low partitions –Force too much to the center –E.g., noises in the hallway can become distracting to work

39 Dangling String Represent bits flowing over a wire through motion and sound. The output is (beautifully?) integrated with our physical environment.

40 Discussion Is Ubicomp defined by the devices or user experience? Imbed vs. Embed? Are inner office window and dangling string really calm and relaxing? Does Calm give more or less information? This is related to ambient display research. UI People know more about this research area?

41 M. Satyanarayanan. "Fundamental Challenges in Mobile Computing", Fifteenth ACM Symposium on Principles of Distributed Computing, May 1996.

42 Key Points What are fundamental challenges in mobile computing (What is so special about mobile computing)? –Resource-limited mobile devices –Mobility is hazardous –Unpredictable wireless networks –Finite power source Adaptation is key to mobility.

43 Evolution from Distributed Systems to Mobile Computing What are fundamental differences between Distributed Systems and Mobile Computing? –Distributed systems = Applications running over Computers Connected Over Network –Mobile systems = Applications running over mobile devices connected over wireless networks –Mobile devices constraints: resource-limited, finite power source, easy-to-lose (weak security) –Wireless network constraints: unpredictability bandwidth and frequent disconnections

44 Adaptation is Key to Mobility Adapt applications to continuously changing computing environment (due to mobility): –Power, network bandwidth / availability, …

45 Adaptation Strategies Need resource management at the system layer to allocate resources to different applications. Need application level semantics, e.g., frame-rate, resolution, etc. The best approach is to have both application and system supports.

46 Extended Client Server Model Traditional (thin) client (fat) server model in distributed computing needed adjustments to address unpredictable network, finite power, and performance. Extended client-server model (called smart client model) places some server functionalities to client.

47 Coda & Odyssey Coda supports application-transparent adaptation. –It is distributed file system (FS). –It can cache/hoard some parts of FS on client. –It can support disconnected operations from FS cache. Odyssey supports application-aware adaptation. – Adapt application quality/fidelity (e.g., video framework, resolution) based on dynamic network condition, power saving, and processing loads.

48 Research Topics for Exploration Caching metrics (what to cache/hoard?) Caching coherence (Semantic callbacks and validators) Algorithms for resource revocation Agility ( 靈敏 ) vs. stability (Global) Resource estimation from local observations

49 M. Satyanarayanan. “Pervasive Computing: Vision and Challenges”, IEEE Personal Communications, August, 2001.

50 Key Points What are fundamental challenges in pervasive/ubicomp computing (What is so special about pervasive computing)? –Effective use of smart spaces –Invisibility –Localized Scalability –Masking Uneven Conditioning We will hear a distinguished talk from author directly. –

51 Discussion What exactly is proactivity? How does it differ from adaptation? Is Ubicomp still about old technical issues.. –Integrating different technologies, devices and services. –Resource discovery protocol –Optimization (different parameters such as power) –Adaptation (with environments)