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Context-Aware Computing: Introduction March 7, 2013 Uichin Lee Parts of slides are adapted from

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1 Context-Aware Computing: Introduction March 7, 2013 Uichin Lee Parts of slides are adapted from

2 Context-Aware Computing Applications, Bill Schilit, Norman Adams, Roy Want, MCSA 1995 Ask not for whom the cell phone tolls: Some problems with the notion of context-aware computing, Tom Erickson, 2002 There is more to Context than Location, Albrecht Schmidt, Michael Beigl and Hans-W. Gellersen, 2001 What we talk about when we talk about context, Paul Dourish, Pers Ubiquit Comput, 2004

3 Gartner’s Top 10 Trend (2012) Contextual and Social User Experience

4 Context-aware computing “software that examines and reacts to an individual’s changing context” Schilit, Adams, & Want (1995) “…aware of its user’s state and surroundings, and help it adapt its behavior” Satyanarayanan (2002) “.. uses context to provide relevant info and/or services to the user” Dey (2001) Context-Aware Computing Applications, Bill Schilit, Norman Adams, Roy Want, MCSA 1995

5 What is context? “any information that can be used to characterize the situation of an entity” Dey et al., (2001) Entity: person, place, or object that is relevant to the interaction between a user and an application (including the user and applications themselves) Who + What + When + Where -> Why? Understanding and Using Context, Anind K. Dey, GIT, Personal and Ubiquitious Computing 2001

6 What is context? Schmidt, Beigl, Gellersen’s model (2001): – A context describes a situation and the environment a device/user is in – A context is identified by a unique name – For each context a set of features is relevant – For each relevant feature a range of values is determined (implicitly or explicitly) by the context There is more to Context than Location, Albrecht Schmidt, Michael Beigl and Hans-W. Gellersen, Computers & Graphics Journal 2001

7 What is context? There is more to Context than Location, Albrecht Schmidt, Michael Beigl and Hans-W. Gellersen, Computers & Graphics Journal 2001

8 Context-aware app dimensions ManualAutomatic InformationProximate selection & Contextual information Automatic contextual reconfiguration CommandContextual commandsContext-triggered actions Dey (2001) – Presentation of info/services to a user – Automatic execution of a service for a user – Tagging of context to info to support later retrieval Schilit, Adams, Want (1995) Context-Aware Computing Applications, Bill Schilit, Norman Adams, Roy Want, MCSA 1995

9 Proximate selection A user interface technique that makes the located objects “emphasized” or “being easier to choose” Located objects – Computer input/output devices; e.g., display, speakers, thermostats – Non-physical objects and services accessed at a particular location; e.g., menus, lists of instructions or regulations – Places that users want to find (like yellow pages); e.g., sorting places according to the distance Context-Aware Computing Applications, Bill Schilit, Norman Adams, Roy Want, MCSA 1995

10 Proximate selection Manually retrieve info based on context

11 Contextual info and commands People’s actions can be predicted by their situations, e.g., library, kitchen, office, etc. Context parameterizes “context command”; e.g., print – by default: print to the nearest printer PARCTAB’s location-based file system – Directories are location names, containing files, programs, and links – Location browser automatically shows the directory that matches with the current location Office: occupants’ finger plans, calendar files Lab: general description of the research group – Location browser also runs “contextual commands” Migrate a remote app’s window to a nearby display Display a library catalog (when entering the library, this button pops up) Context-Aware Computing Applications, Bill Schilit, Norman Adams, Roy Want, MCSA 1995

12 Contextual info and commands Geonotes (Espinoza et al., 2001) – Real-world annotation (post-it?)

13 Contextual info and commands Micro-blog (Gaonkar et al., 2008) Ref:

14 Automatic contextual reconfiguration Process of adding new components, removing existing components, or altering the connection between components Components and connections: servers, their communication channels to clients Context-Aware Computing Applications, Bill Schilit, Norman Adams, Roy Want, MCSA 1995

15 Automatic contextual reconfiguration Virtual whiteboard example: – When entering a room, a mobile host automatically binds itself to the room’s virtual whiteboard SenSay (Siewiorek et al., 2003) – A context-aware mobile phone with four states: Uninterruptible, Idle, Active, and Normal (default)

16 Context-triggered actions Simple condition-action rules invoked automatically Active Badge example: – Rule form: badgeID location event-type action – if I go walk by kitchen, remind me to get coffee (playing a music) Active BadgeCyberReminder (Dey et al., 2000)

17 Context-triggered actions Challenges: – Expressiveness of language for rules – Accuracy of context information Example: Siren (Jiang et al., 2004) IF (firefighter F1 IN room A) AND (surrounding temperature > 1500F) THEN (generate_alert(firefighter F1 in danger)) AND (generate_alert(room A is a dangerous place))

18 Context-awareness as a cushion Pervasiveness of technology – Context-awareness helps technology “get it right” But… – Context is hard to sense Lots of it Subtle – Computers are not “self- aware” like humans

19 Errors When the system does the wrong thing – Automatically locking car doors – Screen saver during presentation – Microphone amplifying a whisper In these examples, is the system or the user at fault?

20 Human in the loop Context data must be coupled with the ability to interpret it, but computers are bad at common sense Having more rules makes the system more complicated; doesn’t solve the fundamental problem Human in the loop – Computers can detect, aggregate, and portray information – Allow human users to interpret and act on it

21 Acquiring Context Smart environment: – Infra for obtaining context and for providing context to mobile apps – E.g., active badge system: a badge sensing system that obtains location info Mobile sensors: – Embedded sensors in smart devices – E.g., digital cameras w/ motion sensors, smartphones w/ light and motion sensors (automatic brightness control, screen rotation)

22 Few thoughts about context Context as representation (so far) – Context is a form of info (known, encoded, represented) – Context is delineable (defining what constitutes context of activities and how apps supports) – Context is stable (for a given app, it would be; though it is app dependent) – Context and activity (content) are separable What we talk about when we talk about context, Paul Dourish, Pers Ubiquit Comput (2004)

23 Few thoughts about context Context as interaction: Dourish (2004) – Context is a relational property (objects  activity) Something is or is not context vs. it may or may not be contextually relevant to some particular activity – Scope of contextual features defined dynamically – Context is an occasioned property Relevant to particular settings, particular instances of action and particular parties to that action – Context arises from the activity It isn’t just “there” but is actively produced, maintained, and enacted in the course of activity at hand What we talk about when we talk about context, Paul Dourish, Pers Ubiquit Comput (2004)

24 Few thoughts about context Context is an emergent property of occasions of interaction (continually negotiated and redefined) Contextual properties take on their meaning or relevance through their relationship to forms of practice – Engaged action around artifacts and information that make those artifacts meaningful and relevant to people


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