Pocket, Bag, Hand, etc. - Pocket, Bag, Hand, etc. - Automatically Detecting PhoneAutomatically Detecting Phone

Context through DiscoveryContext through Discovery

Emiliano Miluzzoy, Michela Papandreax, Nicholas D. Laney, Hong Luy, Andrew T.

Campbelly

Presented by:Lulwah Alkwai

IntroductionIntroduction

Discovery FrameworkDiscovery Framework

Phone Sensing ContextPhone Sensing Context

DesignDesign

System System

ImplementationImplementation

Preliminary System Preliminary System

EvaluationEvaluation

ConclusionConclusion

IntroductionIntroduction

What is “phone sensing context”?What is “phone sensing context”?

• The position of the phone carried by a person (e.g. The position of the phone carried by a person (e.g. in the pocket , hand , backpack , arm , ...) in in the pocket , hand , backpack , arm , ...) in relation to the event being sensed.relation to the event being sensed.

• It is a fundamental building block for new It is a fundamental building block for new distributed sensing application built on mobile distributed sensing application built on mobile phones.phones.

Observation has grown out of implementation of Observation has grown out of implementation of CenceMeCenceMe and and SoundSenseSoundSense..

• CenceMeCenceMe::

• Is a personal sensing system that enables members of social networks to share their sensing presence with their buddies in a secure manner.Is a personal sensing system that enables members of social networks to share their sensing presence with their buddies in a secure manner.

SoundSenseSoundSense::

Top end mobile phones include a Top end mobile phones include a number of specialized (e.g., number of specialized (e.g., accelerometer, compass, GPS) and accelerometer, compass, GPS) and general purpose sensors (e.g., general purpose sensors (e.g., microphone, camera) that enable microphone, camera) that enable new people-centric sensing new people-centric sensing applications.applications.

Discovery FrameworkDiscovery Framework

Phone sensing Phone sensing ContextContext

DesignDesign

System System implementationimplementation

Phone Sensing Phone Sensing ContextContext

AccurateAccurate

RobustRobust

Low duty cycleLow duty cycle

DesigDesignn

• Using the entire suite of sensing Using the entire suite of sensing modalities available on a mobile phone to modalities available on a mobile phone to provide enough data features for context provide enough data features for context discovery at low cost and for increased discovery at low cost and for increased accuracy and robustness.accuracy and robustness.

System System ImplementationImplementation

Feature selection:Feature selection:

1st-191st-19thth: Audio signal : Audio signal classification problemsclassification problems

2020thth: Power of audio signal/raw : Power of audio signal/raw audio dataaudio data

2121stst,22,22ndnd: Mean and standard : Mean and standard deviationdeviation

2323rdrd: # of times exceeds a certain : # of times exceeds a certain pointspoints

TrainingTraining

PredictionsPredictions

(a) (a) FFTFFT power of an audio clip ,when the phone power of an audio clip ,when the phone insideinside

the pocketthe pocket

(b) (b) FFTFFT power of an audio clip ,when the phone power of an audio clip ,when the phone outsideoutside

the pocketthe pocket

(c) (c) CountCount the number of times the the number of times the FFTFFT power exceeds power exceeds

the the thresholdthreshold

Preliminary System EvaluationPreliminary System Evaluation

• The result highlight that the The result highlight that the audioaudio modality modality is is effectiveeffective in detecting the in/out of pocket in detecting the in/out of pocket context with reasonable accuracy.context with reasonable accuracy.

IN/OUTIN/OUT POCKET POCKETA:A: GMMGMMB:B: SVMSVMC:C: GMMGMM TRAINING AND EVALUATING TRAINING AND EVALUATING INDOORINDOORD:D: SVMSVM TRAINING AND EVALUATING TRAINING AND EVALUATING OUTDOOROUTDOORE:E: SVMSVM TRAINING AND EVALUATING TRAINING AND EVALUATING INDOORINDOORF:F: SVMSVM TRAINING TRAINING OUTDOOROUTDOOR AND EVALUATING AND EVALUATING INDOORINDOORG:G: GMMGMM TRAINING USING ONLY TRAINING USING ONLY MFCCMFCCH:H: SVMSVM TRAINING USING ONLY TRAINING USING ONLY MFCCMFCC

ConclusionConclusion

• Initial implementation looks Initial implementation looks promisingpromising , , has potential , when implemented in its has potential , when implemented in its full form to become a core component of full form to become a core component of futurefuture mobile sensing systems. mobile sensing systems.

Thank Thank youyou