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Instant Social Ride-Sharing

Instant Social Ride-Sharing. Gy ő z ő Gid ó falvi * Uppsala University, Dept. of Information Technology Gergely Her é nyi motoros.hu: Online Hungarian Forum for Mobility and Transport Torben Bach Pedersen * Aalborg University, Dept of Computer Science. Outline. Ride-sharing background

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Instant Social Ride-Sharing

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  1. Instant Social Ride-Sharing Győző Gidófalvi* Uppsala University, Dept. of Information Technology Gergely Herényi motoros.hu: Online Hungarian Forum for Mobility and Transport Torben Bach Pedersen *Aalborg University, Dept of Computer Science

  2. Outline • Ride-sharing background • Instant Social Ride-Sharing System / Service • Process and system components • Mobile demo application • Dual-objective grouping of trips into ride-shares • Detour measure between offer and request • Social connection between participants • Calculating a ride-share assignment • Modes of operation • Simulated data sets • Evaluation of transport effectiveness • Conclusions and future work 2008 ITS World Congress, NY, NY

  3. Ride-Sharing Background • Congestion, parking, and pollution are increasing in most cities • A potential solution is ride-sharing (carpooling) • Encouraged by measures: • exclusive lanes, parking places, and reduced road tolls for carpools • But wide-spread adoption is hindered by barriers: • Lack of effective mechanisms for scheduling/coordinating ride-shares • Safety risks • Social discomfort in sharing private spaces • Imbalance of costs and benefits among parties • Current commercial products / system for ride-sharing: • nuRide, Carpoolworld, liftShare, eRideShare, etc… • Post and search trips • Manually construct / negotiate regular ride-shares • Trust managed through a self-regulatory user-rating • Existing systems do not effectively eliminate barriers! 2008 ITS World Congress, NY, NY

  4. Instant Social Ride-Sharing System / Service • Idea: Share a ride with a friend or a friend of a friend! • Exploit exponentially growing popularity of social networkingand the voluntary sharing of personal information online toeliminate the social barrier to ride-sharing • Utilize mobiletechnologies (communication, computing and positioning) to allow instant ride-sharing, automatic scheduling and to help coordinate ride-shares • Question: Are there enough ride-sharing possibilities between friends to allow for effective transport? 2008 ITS World Congress, NY, NY

  5. SRSS Process and System Components 2008 ITS World Congress, NY, NY

  6. SRSS Mobile Demo Application Web demo: http://www.motoros.hu/SRSS/SRSS.html Java mobile application: http://www.motoros.hu/SRSS/SRSS.jad 2008 ITS World Congress, NY, NY

  7. Assignment Update Instant SRSS Assignment Trip Matching Engine Geocoding Social Network DB Ride Coordination Ride Coordination Login (Victor) Define Trip Ride Preferences Submit Offer (Joe) Define & Save Trip Login (Joe) Login (Greg) Social Links Submit Request (Greg) SRSS Mobile Demo Application In Action Waiting For Offer (Victor) Social Links 2008 ITS World Congress, NY, NY

  8. Dual-Objective Grouping of Trips into Ride-Shares • Minimize the extent of the “detour” that offering parties must make in order to serve requests • Maximize the amount of social connections amongst participants of ride–shares •  Expected to increase the social comfort level and trust among ride-share participants •  Leads to increased user acceptance and adoption of ride–sharing 2008 ITS World Congress, NY, NY

  9. Detour Measure Between Offer and Request • Break displacements between origin and destination of an offer and a request into perpendicular offset components • Relative detour: fraction of the weighted average of the offset components and the shared distance • Detour measure is calculated using an SQL function 2008 ITS World Congress, NY, NY

  10. Social Connection Between Participants • Number of relatively short paths between two users indicates the strength of the social connection, ssc • ssc values between pairs of connected users are pre-calculated and stored in an RDBMS using a self-join 2008 ITS World Congress, NY, NY

  11. Calculating a Ride-Share Assignment • Calculate candidate matches between active offers and valid requests such that: • The users of the offer and the request are socially connected • The offering user has to make a detour that is less than a maximum threshold: max_det • The seat supply matches seat demand • Derive a single match score that is linearly related to the required detour and inversely related to the ssc between the users • Iteratively, in a greedy fashion assign requests to offers such that: • As many as possible of requests are assigned to an offer • The total match score of the assignment is minimized • The Ride-Share Assignment algorithm is effectively implemented as a stored procedure in a RDBMS • Refer to the paper for implementation details 2008 ITS World Congress, NY, NY

  12. Modes of Operation • Requests can be assigned to stationary or to mobile (already departed) offers • Offers can depart, in an eagerfashion, immediately after the first assignment, or can wait, in a lazyfashion, for more assignments 2008 ITS World Congress, NY, NY

  13. Simulated Data Sets • Transportation data set: • ST-ACTS: Trip = locations of two consecutive activities • 1.74 million, on average 2.9 km long trips of 550 thousand prospective users for the course of a day • Social network data set: • People tend to make social connections with other people that they frequently interact with in physical space (friends at home, colleagues) • A user is assigned12 random friends, and 12 home and 12 work friends that are live and work close to the user •  social network with 11 million links • SRSS user data set: • Users join SRSS by invitation in the order of the number of received invitations and the utility the user sees in joining 2008 ITS World Congress, NY, NY

  14. Evaluation of Transport Effectiveness • Transport effectiveness for varying number of users and under various parameter settings (max_det and max_wt) are evaluated according to three measures: resource-effectiveness, time-effectiveness, and reliability. 2008 ITS World Congress, NY, NY

  15. Evaluation of Transport Effectiveness (cont.) • For 60,000 users (10% of the population): • AVO-level is raised from 1 to 1.61 • Users wait 2.4 minutes for a ride–share • Offers have to make a detour that is 8% of the shared distance • 91% of the requests can be served • Corresponding savingsduring the course of a single workday in a city like Copenhagen: • 32% of the normal transport cost, specifically: • 176,000 vehicle–kilometers • 14,000 liters of fuel • 32.7 tonnes of CO2–emissions • The proposed SRSS is clearly effective! 2008 ITS World Congress, NY, NY

  16. Conclusions and Future Work • Conclusions • Developed an instant Social Ride-Sharing System/Service (SRSS) along with a mobile demo application • Experiments on simulated data sets show that the proposed SRSS can provide highly effective transportation and is feasible • Future work • Road network distance based detour measure • Highly scalable implementation of SRSS using a data stream management system • Alternative system architecture possibilities: distributed 2008 ITS World Congress, NY, NY

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