Slide 1OutlineIntroductionHardware DesignMobile Sensor TierSensor Access Point (SAP) TierBackend Server TierSoftware DesignBikeNet Role AssignmentBikeNet Role Assignment Cont.Intra-BAN & Inter-BAN ManagementData Exchange ServicesGround Truth SensingQuery ManagementRoute CheckpointsQuery Submission PortalSensor Data Storage, Processing, VisualizationSystem State DatabaseIncentivizing UsagePrivacy and TrustSystem EvaluationCyclist Experience Mapping ExperimentsCyclist Experience Mapping ExperimentsSocial Cycling ExperimentServices Performance ExperimentsTown-Scale System Scenario ExperimentTown-Scale System Scenario ExperimentConclusions & SignificanceMy Own ThoughtsReferencesBikeNet: A Mobile Sensing System for Cyclist Experience MappingSHANE B. EISENMANGAHNG-SEOP AHNColumbia UniversityEMILIANO MILUZZO, NICHOLAS D. LANE, and RONALD A. PETERSONANDREW T. CAMPBELLDartmouth CollegeFrom ACM Transactions on Sensor Networks (TOSN), vol. 6, no. 1, December 2009Presented by:Travis CossairtFebruary 21, 2011EEL 6788Outline•Introduction•Hardware Design•Software Design•Incentivizing Usage•System Evaluation•Conclusions & SignificanceIntroduction•“BikeNet is a mobile sensing system for mapping the cyclist experience”•Leverages the MetroSense Architecture[2] •Project embeds multiple hardware sensors onto a bicycle•Dual mode operation for data collection to handle areas without network connectivity•Web-based portal created for community sharing and data viewingHardware Design•Organized into 3 tiers: •Mobile Sensor Tier•Sensor Access Point (SAP) Tier•Backend Server TierMobile Sensor Tier•# of sensors that are bicycle and human-mounted to create a BAN (Bicycle Area Network)•Gathers data on cycling performance, cyclist heath/fitness, and environment on route•Includes: 2-axis accelerometer, thermistor, photodiode, microphone, camera, multiple radios, GPS, C02, Biofeedback, magnetometer (car detection), •etc.Sensor Access Point (SAP) Tier•Offers high performance/reliability and secure gateway access from sensor tier to backend servers•Point of command to task available sensors with user application requests/queries•Can also be fitted with sensors to provide context/validation for any uploaded data•Authors experimented with both static (wired directly to internet e.g. Tmote Invent plugged into IEEE 802.11 access point) or mobile (e.g. radio access via phone GSM/GPRS)Backend Server Tier•Backend members are Ethernet-connected servers that have “practically unbounded storage and computational power”•Provides number of services to architecture that will be described in more detail in Software Design (application request/queries in sensor tier, and to retrieve/visualize sensed data)Software Design•The software system provides a number of services to the 3 hardware tiers including:•BikeNetRoleAssignment•Intra and Inter-BAN Mangement•Data Exchange Services•Ground Truth Sensing•Query Management•Route Checkpoints•Query Submission Portal•Sensor Data Storage/Processing/Visualization•System State DatabaseBikeNet Role Assignment•BAN divides functionality into logical roles:•Pedal Sensor/Wheel Sensor•Tilt Sensor/LateralTiltSensor: can measure slope/terrain•CompassSensor•MetalDetector: Detect passing cars•SyncSprinkler: common absolute notion of time/location to all members•LocalDisplay: means to locally display data•CO2Sensor•SoundSensor: ambient noise + voice triggered sensing•CameraSensorBikeNet Role Assignment Cont.•PersonalNode provides control of short-range radio over other sensing roles•Signals start/stop of trip •Only REQUIRED role, all other optional, as well as storage of user profile preferences•PersonalNode communicates with all local sensors in the BAN via a “hello”/”ack” type of protocol•Sensors respond back with what role they can/are willing to fulfillIntra-BAN & Inter-BAN Management•Localization & Synchronization managed by SyncSprinkler role that does periodic broadcasts to update time/location to all BAN members•When PersonalNode establishes all roles fulfilled in BAN, “Ready” state occurs. When ride starts, a button click broadcasts to all members to start recording data•System supports both event-based and continous sensing, as setup by the profile stored in PersonalNode•LocalDisplay communicates to BAN members to provide real-time display of sensor data communicating via BluetoothData Exchange Services•3 types of data exchange occur in system:•Tasking exchange (mobile sensing<->SAP): handles bootstrapping the sensors as well as requests from backend to particular BAN•Mulling exchange (between members of mobile sensing tier i.e. other cyclists): allows other BAN’s outside of SAP range to be exchanged and uploaded for real-time requests from back end•Uploading exchange (mobile sensing<->SAP): uploads data when in range of a SAPGround Truth Sensing•SAPs equipped with special sensors to provide “ground-truth” measurements•Refers to trusted, high-fidelity, always accessible stream of data•Used to validate or invalidate uploaded data for samples expected to have high expected correlation•E.g. temperature sampled at same time•Can also be used to self-calibrate a BAN within radio range of a SAPQuery Management•SAP handles queries from both backend user and PersonalNode of a BAN•Invokes sensing resource discovery to find sensing resources available to meet the request•Checks both ground-truth sensors on SAP as well as any BAN’s within radio range•If sensor resource available, invokes the task•E.g. If phone used as SAP, could be invoked to take photoRoute Checkpoints•Location-specific entities to allow storage/retrieval of location-specific data e.g. average speed up a particular hill•Could be used to display other cyclists performance at that location (competition), or your previous performance•Can be created by the cyclist through UI on LocalDisplay or via web interface before the ride (w/ privacy indicator)Query Submission Portal•Web portal containing graphical presentation of cyclist data•Allows real time querying of BANs if cyclist using a GPRS connection device•Includes ability to query BAN’s location, capture camera image, sample microphone•Communicates by sending an SMS to the BAN’s phone over GPRSSensor Data Storage, Processing, Visualization•Repository provides location for long-term storage of cyclist
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