1. Cell Phones and GPSSean J. Barbeau, Ph.D.Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau

2. Mobile Computing Opportunities Proliferation of cell phones & apps 5.9B mobile subscriptions worldwide, approx. 87% of globalpopulation (Sept. 11)[1] 102.4% U.S. mobile subscriber rate (322.9M) (Jun. 11) [2] 26.6% of U.S. Households are WirelessOnly (April 11) [3] 29B apps downloaded in 2011, up from 9B in 2010 [4] Evolution of positioning technologies U.S. F.C.C. e-911 mandate for locating cell phones ~2001 79.9% of cell phones shipped in Q4 2011 (318.3M) hadintegrated GPS [5][1] International Telecommunications Union, ITC Facts and Figures The World in 2011 International Telecommunications Union, Sept 2011.[2] CTIA. Wireless Quick Facts, http://www.ctia.or g /a dvocacy /res earch /inde x.cfm/a id /10323[3] National Center for Health Statistics. Wireless Substitution: State -level Estimates from the National Health Interview Survey , National Health Statistics Reports, Number 39, April 20, 2011.[4] ABIresearch. Android Overtakes Apple with 44% Worldwide Share of Mobile Apps Downloads, October 24, 2011.[5] Rebello, Jagdish. Four Out of Five Cell Phones to Integrate GPS by End of 2011, Integrate -GPS-by-End-of-2011.aspx 2Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 3. Google Maps/Inrix/Foursquare/Facebook/Latitude Maps and Navigation Real-time traffic Allows users to check-into locations to earnpoints/rewards/discounts Alerts you to friend check-insProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau3Sugar 4. Location technology available to cellular network providersProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau4 5. Positioning Technologies Global Positioning System(GPS) Uses satellite signals todetermine its current location Can be accurate within 3meters Small enough to manufactureas a chip inside phone Assisted GPS uses dataprovided by the network toreduce time-to-first-fixProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 6. Positioning Technologies Advanced Forward-LinkTrilateration (AFLT) Phone takes measurementsof network signals andreports time/distance backto network server to doposition calculation Used in CDMA networks Accurate from 50-250m Typically not exposed toapps due to networkoverheadProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 7. Positioning Technologies Uplink Time Difference ofArrival (U-TDOA) Towers take measurementsof device signals andposition is calculated bynetwork servers Used in GSM networks Accurate from 50-250m Typically not exposed toapps due to networkoverheadProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 8. Positioning Technologies Cell Sector Cellular networkidentifies the section ofthe cell that the phone isin Accuracy depends onsize of cell (100m-20km)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 9. Positioning Technologies Cell-ID Cellular networkidentifies the cell towerthat the phone iscommunicating with Accuracy depends onsize of cell (100m-20km) Least-accuratepositioning methodProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 10. Network vs. Handset-InitiatedHandset-initiated app (or device)made location requestNetwork-initiated webapplication, or cellular carrier, madelocation requestProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau10 11. MS-assisted vs. MS-based Mobile Station (MS) = mobile device MS-assisted = Device provides additional info, butnetwork server calculates the final position E.g., A-FLT, U-TDOA Typically only used for e911 due to burden on carriers MS-based = Network provides additional info, but thedevice calculates the final position E.g., traditional assisted GPS Used by mobile apps Note that you can have MS-assisted GPS Device collects GPS signal info, but sends to server, wherepseudoranges are calculatedProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau11 12. MS-based Assisted GPS Assistance information implemented within the cell networkcommunication protocol itself Device must talk to Positioning Determination Entity (PDE)server every few hours Scales poorly (i.e., significant cost to add more devices) Maintained solely by cell carrier Autonomous mode may not be possible Depends on deviceOperating System(e.g., Linux)Link Layer(e.g., CDMA IS-95)Custom Network ServerOperating System(e.g., Linux)(e.g., Intel CPU/Motherboard)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau12Hardware(e.g., Qualcomm chipset)Device Cell NetworkHardwareCarrier Servers 13. gpsOneXTRA Predictive ephemeris model good for 7 days Accuracy degrades over time typically refreshed every 48 hrs Packet data over internet (application layer) scales well Server can be maintained by third-party (e.g., Google, Apple)Application Layer(e.g., HTTP, FTP, VOIP)Tranport Layer(e.g., TCP, UDP)Network Layer(e.g., IP)Operating System(e.g., Linux)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauApplicationServerOperating System13Link Layer(e.g., CDMA IS-95)Cell Network(e.g., Linux)Hardware(e.g., Intel CPU/Motherboard)ServerHardware(e.g., Qualcomm chipset)Device 14. gpsOneXTRA (Cont) Autonomous GPS supported On Android, applications given limited control over refreshinggpsOneXTRA info Example file (~39kB) - http://xtra3.gpsonextra.net/xtra.bin Drawbacks: May not be as accurate as traditional MS-based Assisted GPS Requires internet connectionProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau14 15. GPS Data Characteristics Can VaryTwo major influences1. Mobile Device Hardware & Software> GPS hardware sensitivity> Antenna quality and device integration> Assisted vs. Unassisted GPS> MS-based vs. gpsOneXTRA> Firmware/software filters2. Environment> Indoor / Outdoor> Urban Canyons> Building materials> Shielding by enclosure (e.g., purse, car)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 16. Benchmarking GPS accuracy is useful95th percentile: 550m68th percentile: 398m50th percentile: 335mSamsung Moment HTC EVO 4G 172 metersEnvironment: Indoor, 2nd floor, on desk near window, Tampa, FlProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau172 metersData from GPS Benchmark (www.gpsbenchmark.com) 17. HTC Hero 29.7 meters HTC EVO 4GEnvironment: Indoor, 2nd floor, on desk near windowProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau29.7 meters 18. Location technology used by mobile appsProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau18 19. Smartphone Network Location Used when you cant get a GPS fix Typically very quick TTFF (sub-second) Based on hybrid of WiFi and cell networklocation info, depending on availability WiFi position depends on geostamped SSIDnetwork identifierProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau19 20. Samsung Galaxy S3 (Sprint)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau20Cell network based location Wi-Fi based locationAndroid 4.1.2 21. Indoor Location Soon! More precise Wi-Filocation Dead-reckoning -based onaccelerometers,barometers, and othersensors Requires extensiveground-truthing21 Googles Floor Plan Maker AppProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 22. USF Library 1st gen. indoor location isavailable at USF library Floor plan has beenuploaded by USF Some measurements: https://docs.google.com/presentation/d/1AK3KDU8kqpT6hullzIrU6EVy_CHx58LEKe7AremGEBc/edit?usp=sharingProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau22 23. Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau23 24. Known Arch. Limitations Frequent GPS sampling (4 s) and transmissions toserver cost significant battery energy1. Fixed-intervalLocationupdatesJava ME / AndroidProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau24Location-Aware Application(Device-side)ServerLegendLocation DataDevice Platform SoftwareLocation API I/O APIVirtual Machine2. Send data to serverSOAP/ SIPMobile Device 25. Impact of GPS on Battery Life148.0416141210864204 sec. sampling intervalBattery Life (hours)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauRequirementSanyo Pro 20025Sprint CDMAEV-DO Rev. Anetwork 26. Impact of Wireless Tx on Battery Life147.0216141210864204 sec. Tx intervalBattery Life (hours)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauRequirementMotorola i58026Nextel iDENNetworkJAX-RPC 27. Impact of GPS & Wireless Txon Battery Life144.2116141210864204 sec. sampling intervalBattery Life (hours)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauRequirementSanyo Pro 20027Sprint CDMAEV-DO Rev. ANetworkUDP 28. Cellular Data Transfer Limitations Location tracking once per secondequals 86,400 records (~10.3MB) forone user on one day Most cellular carriers only offerlimited data plans e.g., Verizon = $20 per month for 1GB ~10.3MB per day = 319.3MB permonth Almost 1/3 of users plan would belocation dataProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau28 29. U.S. Patent # 8,036,679 Optimizing performance of location-aware applicationsusing state machines.IEEE Pervasive Computing, vol. 10, no. 3, pp. 58-67, July-Sept. 2011. 2011 IEEEProceedings of IEEE UBICOMM 2008 The Second International Conference onMobile Ubiquitous Computing, Systems, Services, and Technologies, Valencia, Spain,September 29 October 4, 2008. 2008 IEEEThe Journal of Navigation, volume 64, issue 03, pp. 381-399. July 2011. 2011The Royal Institute of Navigation.Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau29 30. GPS Tracking High-definition view oftravel Frequent sampling allowsus to determine: Path, distance traveled Origin-Destination pairs Avg. speeds Enables high-accuracy real-time,historical LBS Challenges: Battery life Amount of dataProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau30 31. GPS Tracking Infrequent trackingsolves energy, dataproblems BUT, doesnt give us thedata we want: Path, distance traveled Origin-Destination pairs Avg. speedsProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau31 32. What is Stationary?Detecting User Movement4 second GPSsampling5 minute GPSsamplingMoving Stopped d GPS noise causes uncertaintyin states Many false transitions wastebattery energyProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau 33. GPS-Auto SleepState[0]Gradually move towards state[0] when(low_speed_threshold < current_speed moved_distance_threshold).State[1]State[n 1]AWAKE ASLEEP Dynamically adjust the GPS sampling interval based on user movementProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauState[n]Move directly to state[0] when current_speed >high_speed_threshold.GPS SamplingInterval = 4 sec.GPS SamplingInterval = 8 sec.GPS SamplingInterval = 128 sec.GPS SamplingInterval = 256 sec.After leaving state[0], gradually move towards state[n] when ((current_speed max_walk_speed(Optional)Conditional Evaluations = TRUE?(for Real-time Applications)NOlastTriggerPoint=currentLocation(changeInDirection() >angle_threshold) AND(currentSpeed >min_speed_threshold)?Critical PointAlgorithmProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau40START(Input = currentLocation)TransportationMode=WALKINGTransportationMode=VEHICLEFirst Point?lastCriticalPoint=currentLocationlastCriticalPoint=lastTriggerPointYESNOYESNOYESNO(Since currentLocation is first point insequence, it is saved as both thelastCriticalPoint and LastValidPoint)(lastTriggerPoint is a CriticalPoint, andis stored as lastCriticalPoint for futureexecutions of CP algorithm andreturned to application)(No Critical Points were found)YESReturn currentLocationlastTriggerPoint=currentLocation(Optional) Reset ConditionalEvaluation Variables(for Real-time Applications)Return Return null lastCriticaPoint changeInDirection() Uses angle threshold Changed per speed min_speed() If currentSpeed >min_speed, device is moving Real-time ConditionalEvaluations (Optional) timerExpired()? distanceCounterExceeded? receivedServerProbe? 41. Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauSanyo 7050Sprint CDMA1xRTT NetworkUDP41Effect of Wireless Transmission Interval on Battery Life 42. Angle 1Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau42 43. Angle 2Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau43 44. Angle 3Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau44 45. Angle 4Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau45 46. Angle 5Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau46 47. Angle 6Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau47 48. Angle 7Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau48 49. Angle 8Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau49 50. Angle 10Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau50 51. Angle 11Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau51 52. Angle 15Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau52 53. IntroductionKnown LBSArchitectures Angle 18LimitationsProposed LAISYCArchitectureEvaluation ConclusionsProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau53 54. Accuracy Evaluation using DistanceFull GPS PathaProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau54Sampled GPS positionCritical Point pathCritical Pointb c defgxyDistancefull_GPS_path = a + b + c + d + e + f + gDistancecritical_point_path = x + y = _ _ _ _ __ IntroductionKnown LBSArchitecturesLimitationsProposed LAISYCArchitectureEvaluation Conclusions 55. # Critical Points vs. Distance Error Percentage605040302010WalkProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau20.00%18.00%16.00%14.00%12.00%10.00%8.00%6.00%4.00%2.00%0.00%01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Distance Error PercentageNumber of Criticdal PointsAngle Threshold (Degrees)Number of Critical Points Total Number of Points Distance Error Percentage55Chosen WalkAngle Threshold= 4.5 degreesIntroductionKnown LBSArchitecturesLimitationsProposed LAISYCArchitectureEvaluation Conclusions 56. # Critical Points vs. Distance Error Percentage40035030025020015010050CarProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau20.00%18.00%16.00%14.00%12.00%10.00%8.00%6.00%4.00%2.00%0.00%01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Distance Error PercentageNumber of Criticdal PointsAngle Threshold (Degrees)Number of Critical Points Total Number of Points Distance Error Percentage56Chosen CarAngle Threshold= 3 degreesIntroductionKnown LBSArchitecturesLimitationsProposed LAISYCArchitectureEvaluation Conclusions 57. Critical Point Algorithm Avg. GPS reduction of 77% per trip Avg. 18.8kB saved per trip Average distance error percentage under 10% On avg., as Tx interval doubles battery life doublesProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau57IntroductionKnown LBSArchitecturesLimitationsProposed LAISYCArchitectureEvaluation ConclusionsMin Max Avg.5thpercentile25thpercentile50thpercentile68thpercentile95thpercentileTotal Critical Point Count 2 322 35 3 13 27 38 97Total GPS Fix Count 20 3,710 193 31 74 130 188 511% Savings 20.83% 99.40% 77.43% 47.97% 69.49% 80.00% 86.83% 95.84%Bytes Saved* 595 403,172 18,883 2,380 6,426 12,138 17,493 54,788Distance Critical Points (m) 0.00 1,043,805.50 7,437.09 328.14 1,162.37 2,675.00 4,049.37 22,815.61Total Distance (m) 2.36 1,087,043.20 7,878.02 380.79 1,252.55 2,913.39 4,345.91 24,231.34Distance Error Percentage 0.00% 100.00% 8.90% 1.94% 3.98% 6.20% 8.70% 24.11%* Based on 119 bytes per UDP payload 58. Conclusions Many different positioning methods for mobiledevices with a cellular connection All devices are different Hybrid technologies will dominate next 5-10 years Indoor location is next big thingProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau58 59. Extra slidesProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau59 60. U.S. Patent # 8,036,679 Optimizing performance of location-awareapplications using state machines.IEEE Pervasive Computing, vol. 10, no. 3, pp. 58-67, July-Sept. 2011. 2011IEEEProceedings of IEEE UBICOMM 2008 The Second International Conference onMobile Ubiquitous Computing, Systems, Services, and Technologies, Valencia,Spain, September 29 October 4, 2008. 2008 IEEEThe Journal of Navigation, volume 64, issue 03, pp. 381-399. July 2011. 2011The Royal Institute of Navigation.Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau60 61. GPS Speed Observations When Stationary Indoors0.003.25(n = 165, recorded over 5.5 hours)0.360.253.503.002.502.001.501.000.50 stopped_speed_threshold = 1 m/s 95th percentile of horizontal error high_speed_threshold = 1.5 m/s0.51 98th percentile of horizontal error 61Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau1.4351.59250.00Min Max Avg 50thpercent.68thpercent.95thpercent.98thpercent.99thpercent.Speed (m/s)Speed Error 62. GPS Auto-Sleep moved_distance_threshold = 100 m Based on max. observedhorizontal error of 90.69 mHorizontal Error Statistics (meters)True LocationMotorola i580Sanyo 7050Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau62Device GPS TypeSampleSizeMin Max Avg 50th 68th 95th RMSEMotorola i580 Assisted 478 0.74 90.69 15.16 9.78 15.15 47.9 21.64Sanyo 7050 Assisted 1513 0.16 32.04 8.78 6.23 9.33 24.44 11.33 63. GPS Auto-SleepProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau63 high_horizontal_accuracy_threshold = 80 m Based on max. observed hor. acc. of 58 m 64. IEEE Pervasive Computing, vol. 10, no. 3, pp. 58-67, July-Sept. 2011,doi:10.1109/MPRV.2010.48 2011 IEEEThe Journal of Navigation, volume 64, issue 03, pp. 381-399. July 2011. 2011 The Royal Institute of Navigation.Proceedings of IEEE UBICOMM 2008 The Second InternationalConference on Mobile Ubiquitous Computing, Systems, Services, andTechnologies, Valencia, Spain, September 29 October 4, 2008. 2008IEEEProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau64IntroductionKnown LBSArchitecturesLimitationsProposed LAISYCArchitectureEvaluation Conclusions 65. Critical Point AlgorithmLast Critical Point[ ] [ ] [ ]Last Trigger Point (Under Evaluation)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau65Critical Point Evaluation Sliding WindowNon-critical Point (discarded)Current Point 66. Critical Point AlgorithmIteration X Iteration X+1 Iteration X+2Last Critical Point[ ] [ ] [ ]Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau66Critical Point Sliding Window Memory RequirementsNon-critical Point (discarded)Current Point[ ] [ ] [ ][ ] [ ] [ ]Last Trigger Point (Under Evaluation) 67. Critical Point Algorithm1.61.41.21.00.80.60.40.2Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau670.0Min Max Avg 20thpercent25thpercent50thpercent68thpercent95thpercentStd devSpeed (meters per second)Outdoor Walking GPS Speedn = 53 min_speed_threshold = 0.1 m/s Based on walk speed 25th percentile of 0.2 m/s, 20th percent. of 0 m/s 68. When comparing a) all points to b) critical points using a min_speed_threshold of0.1 meters per second, the general walking path of the user is preserved, with somefiltering at the beginning of the trip (bottom left of each image)Protected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau68a)b) 69. Over 97% of the GPS drift shown here at an indoor stationary location can be filteredout by the Critical Point Algorithm when using a 0.1 meters per secondmin_speed_thresholdProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau69MinSpeedNumber ofCritical PointsTotal Numberof Points % SavingsBytesSaved*Walking 0 50 53 5.66% 3570.1 39 53 26.42% 1,666MinSpeedNumber ofCritical PointsTotal Numberof Points % SavingsBytesSaved*Stationary 0 904 3519 74.31% 311,1850.1 91 3519 97.41% 407,932* Based on 119 bytes per UDP payload 70. Critical Point AlgorithmPossible true pathObserved PathProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau70Possible true position when sampledSampled GPS positionEstimated horizontal accuracy (68th percentile by Java ME specification) 71. Funded by: National Center for Transit Research US Department of Transportation Florida Department of TransportationProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. Barbeau71IntroductionKnown LBSArchitecturesLimitationsProposed LAISYCArchitectureEvaluation Conclusions 72. TRAC-IT Created for bus, bike, walk,car travel data collection Passive and Active modes Simultaneous location-basedservices as incentiveProtected under U.S. Patents #8036679, #8045954, #8140256, #8145183, #8169342, Other Patents Pending USF 2012,. 2014 Sean J. BarbeauPurpose of Trip:72TRAC--IIT(1) Work Related(2) Shopping(3) PickupSomeone(4) Go Homeetc. ...