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Ch 6*: Spatial Networks

* Book Chapter: Spatial Databases: A Tour (Prentice Hall 2003). Encyclopedia Articles A Critical-Time-Point Approach to All-start-time Lagrangian Shortest Paths: A Summary of Results. Venkata M.V Gunturi , Ernesto Nunes , KwangSoo Yang, and Shashi Shekhar. SSTD 2011.

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Ch 6*: Spatial Networks

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  1. * Book Chapter: Spatial Databases: A Tour (Prentice Hall 2003) • Encyclopedia Articles • A Critical-Time-Point Approach to All-start-time Lagrangian Shortest Paths: A Summary of Results. Venkata M.V Gunturi, Ernesto Nunes, KwangSoo Yang, and Shashi Shekhar. SSTD 2011. • Time-Aggregated Graphs for Modeling Spatio-temporal Networks. Betsy George and Shashi Shekhar. Advances in Conceptual Modeling - Theory and Practice 2006. • Spatio-temporal Network Databases and Routing Algorithms: A Summary of Results. Betsy George, Sangho Kim, Shashi ShekharSSTD 2007 • Time Aggregated Graphs. Betsy George and Shashi Shekhar. Encyclopedia of Database Systems. • Spatial Network Databases. Betsy George and Shashi Shekhar. Encyclopedia of Database Systems. Ch 6*: Spatial Networks Team 6 Reem Ali Amr Magdy

  2. Relevance to Course • Many geographic problems can be represented using a network. • e.g. deciding what route to take in a transportation road network. • Related chapters: • Textbook Section 3.4 (Network Spaces) and Section 5.7(Representation and Algorithms). • Spatial Databases Ch. 6: Spatial Networks

  3. Related Material in Textbook • Spatial Networks • Examples: Road, Train and River networks • Modeling: Conceptual, Logical, Physical • Graph Algorithms: e.g. Dijkstra’s for Shortest path

  4. Novelty in Encyclopedia Articles • Spatio-temporal Networks: • Definition ?

  5. Novelty in Encyclopedia Articles • Spatio-temporal Networks: • Definition: spatial networks whose topology and parameters change with time. • Examples: • road networks status changes from time to another due to traffic changes • air travel paths changes due to weather conditions • New models (Time-Aggregated Graphs) and algorithms for spatio-temporal networks are proposed.

  6. Societal Motivation • Road Networks • e.g., All start times shortest paths, Minimizing travel times, Freight delivery services, emergency traffic planning. • Air travel networks • e.g., flight route planning

  7. Computer Science Motivation • Snapshot-based Graph Collection • Time-expanded Graph • Time-aggregated Graph • Gain • Compact representation (i.e., less storage) A A 2 A 1 C C C 3 1 A 2 [1,2,-] 3 B 1 B B C [2,3,1] at t=0 at t=1 at t=2 [1,-,3] B t=0 t=2 t=1 t=3 t=4 t=5 A0 A2 A1 A3 A4 A5 B0 B2 B1 B3 B4 B5 C0 C2 C1 C3 C4 C5

  8. Computer Science Motivation • New algorithms • Best start time shortest path • All start time shortest paths

  9. All Start Time Shortest Paths • Shortest path does not change every time instant • Instead, each interval of time hasshortest path e.g., rush vs. non-rush hour • One path calculation is required per interval(big computation saving) • Start time instants when the shortest path between a source and destination may change are called critical time points

  10. Thank You

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