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Exploring Context

Exploring Context. Motivation. Hans Christian von Baeyer [vB03] Adapted text to picture. Goals. Examine basic concepts concerning context Defining context and context-aware Role of context in building systems Expose to issues while designing a system

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Exploring Context

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  1. Exploring Context

  2. Motivation • Hans Christian von Baeyer [vB03] • Adapted text to picture CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  3. Goals • Examine basic concepts concerning context • Defining context and context-aware • Role of context in building systems • Expose to issues while designing a system • Look at things from a million feet in the sky • Bridge Information Dynamics • Fuse with other trains of thought • Primarily focused on the context aspect CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  4. Caveats • You will/may not agree with everything said • Make your own judgments about various topics • Form your definition of context and context-aware • We will not focus on enabling technologies • Plenty of mechanisms that involve context • Focus on choosing the best fit mechanism • More raised issues than discussed solutions CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  5. Technology Concerning Context • Ideas to think about • Sensing Mechanisms for capturing context • Modeling and Storingcontext • Inferringcontext from context • Exchangingcontext between entities • Usingcontext in decision making CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  6. What do we mean by context? Defining Context CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  7. Conundrum for Defining Context • Define context then develop the system? • System adheres to the definition of context • Develop the system then define context? • Definition highly dependent on the system • Hybrid development and defining? • Iterative and agile software engineering concepts CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  8. Not Ready to Define Yet • Already have ideas in your perceived reality • Life experiences will influence your definition • Information Dynamics defined context • We will come back to definitions later • In the meantime, if you did not do it already: • Write down your definition of context • We will ask you to do it again later CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  9. The Two Core Aspects of Context • Two of the most studied aspects of context • Computer Science, Philosophy, Mathematics, ... • Everything has these two pieces of context CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  10. How do living and artificial beings acquire information? Physiological and Computer Perception CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  11. Primary Physiological Senses • Early (if not earliest) classification of the senses [Ari91] CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  12. Simple Analysis of the Senses CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  13. Further Analysis of the Senses CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  14. Input Mechanisms in Computers CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  15. Simple Analysis of the Input CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  16. Further Analysis of the Input CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  17. Sensing in Information Dynamics Entity Information Physical World Perceived Reality Representation CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  18. Interpretation with a Goal Goal Evaluation of Interpretations Interpreting the Perception Perceiving the State of the World The World • Stages of Interpretation [Nor02] • We will see expanded model later CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  19. The Location Stack Intentions Activities Contextual Fusion Arrangements Non-Context Layers Fusion Measurements Sensors • Layered model for multiple location sources [HBB02] • Similar to the OSI model CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  20. Interpretation with Verification The World Our Interpretation Where Our Interpretations Come From 1. Initial Perception Context The World Body of Knowledge 3. Synthesis 2. Initial Classification 4. Test 5. Prediction 6. Test Informed Perception • A Model of Interpretation [McC04] • Primarily concerned with business document exchange CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  21. Importance of Interpretation Design Model User’s Model Designer User System System Image • Mental Models [Nor02] • Do we interpret messages as intended? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  22. Mars Climate Orbiter • http://en.wikipedia.org/wiki/Mars_Climate_Orbiter • Downloaded February 5, 2009 (Mentioned in [McC04]) CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  23. Missing Context • Rotation Jet Miscalculation (Standards) • NASA’s de facto standard: Metric Units • Hardware: Jet Propulsion Laboratory • Metric Units (Newton-seconds) • Software: Lockheed Martin Astronautics • Imperial Units (pound-seconds) • Data from [Obe99] • What could have been done to prevent this? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  24. Accounting for Context • Calculations • Off by a factor of 4.45 • Not an order of magnitude • System checks • Sensor checks • Take other factors into account (i.e. path) • Calculations from [Obe99] • We will come back to a similar example later CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  25. Understanding Scales • On a scale of 1 to 10, • …how much pain do you feel? • …how do you rate this essay/movie/book? • …how fast/cool is this car? • Questions to ask about these scales: • How did the person assign the value? • Is the scale absolute or relative to other values? • Can the person’s value be trusted? • What other context relates to the value? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  26. How does effective communication take place? Effects of Context on Communication CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  27. Chinese Whispers, or Telephone • Example from [vB03], though he did not invent it • Communicate Message from Alice to Bob CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  28. Typical Result of Playing Telephone • Alice’s original message never made it to Bob • Why did the message become garbled? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  29. Information Theory Explanation Physical World Entity A Information Source Message Transmitter Signal Noise Source Entity B Destination Message Receiver Received Signal • Altered from [Sha48], did not have boundaries • Each student represents a noise source CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  30. Technical Information • Claude E. Shannon [Sha48] • Does not account for why noise events occur CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  31. Information Dynamics Explanation Entity A Entity B Information Information Physical World Perceived Reality Perceived Reality Technical Information Representation Representation • Each entity goes through this process • Differences in context and culture change the message CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  32. Chinese Characters • Scenario attributed to Jan Kåhre • Believes Shannon information represents one of many ways to measure information content • Englishman picks up Chinese newspaper • Does not understand any of the characters • Information content equals zero • Person who understands translates to the person • Information content much greater • Example from [vB03] CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  33. Information Content CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  34. Understanding Results • What context do we need to know to reproduce results from papers? • Do we believe the results given? • Do the results convince us of the arguments? • Issues to consider: • Listed specifications for the tests • Granularity of the results • Intangibles not listed in the paper: • Time of Day, Location, Temperature, Altitude, … CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  35. How do we maintain continuous goals? Maintaining Goals with Context CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  36. Goal: Automotive Cruise Control CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  37. Open-Loop System System Input System Output System • Throttle controlled by system • Factors not included: • Hills, wind, road conditions, … CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  38. Closed-Loop System Measured Error System Input System Output Controller System Sensor • Basis of control theory • Introduce a feedback mechanism • Monitor the output of the system • Adjust throttle control as necessary CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  39. Interpretation with a Goal Goal Intention to Act Evaluation of Interpretations Sequence of Actions Interpreting the Perception Execution of the Action Sequence Perceiving the State of the World The World • Seven Stages of Action / The Action Cycle [Nor02] • Stages of Execution and Stages of Interpretation CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  40. Issues: Plane Autopilot • Co-pilot noticed fuel being fed to all engines from only one fuel tank • Steering wheel learned slightly to the right • Incrementally shifted, pilots did not notice • Autopilot slowly autocorrected roll • Roll caused by fuel imbalance • Other sensors indicated fuel levels • From [Nor90], need accurate feedback and interaction • How do you sufficiently account for different scenarios? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  41. How do others define context? Defining Context, Revisited CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  42. Technical Information Keywords • Information Theory-centric book [Les01] • What can we learn from the lessons from that field? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  43. Forces of Evidence • From [Schu94], essentially the value of information • With respect to a certain circumstance or frame CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  44. Context in Documents • [McC04] • Concerned with business systems CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  45. Formal Context • [Dey01] • Generally accepted definition in hundreds of papers. CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  46. Operational Context • [ZLO07] expands Dey’s formal definition • Includes operational aspect of context CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  47. We continually redefine the meaning of context. Context goes beyond the definitions presented. How does context influence the way we define systems? Can you derive my definition of context from these slides? What Next? CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

  48. References CMSC818G: Information-Centric Design of Systems Topic: Exploring Context

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