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Modelling and Predicting Future Trajectories of Moving Objects in a Constrained Network appeared in “Proceedings of the 7th International Conference on Mobile Data Management (MDM'06),japan”. Jidong Chen Xiaofeng Meng Yanyan Guo S.Grumbach Hui Sun
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Modelling and Predicting Future Trajectories of Moving Objects in a Constrained Network appeared in “Proceedings of the 7th International Conference on Mobile Data Management (MDM'06),japan” Jidong Chen Xiaofeng MengYanyan GuoS.GrumbachHui Sun Information School, Renmin University of China, Beijing, China Presented by Yanfen Xu
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Introduction • Focus: • location modelling • future trajectory prediction • Contributions: • present the graphs of cellular automata (GCA) model • propose a simulation based prediction (SP) method • experiments evaluation
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Related Work • The modeling of MOs: • MOST model, STGS model, abstract data type • connecting road network with MOs • first in 2001, wolfson et. Al • L.Speicys: a computational data model • MODTN model • Prediction methods for future trajectories • Linear movement model • Non_linear movement models, using • quadratic predictive function, • recursive motion functions • Chebyshev polynomials
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Graphs of Cellular Automata Model (GCA) • Modeling of the road network: • cellular automata • nodes • edges • GCA state: a mapping from cells to MOs, velocity
Graphs of Cellular Automata Model (GCA) • Modeling of the MOs • position can be expressed by (startnode, endnode, measure). • the in-edge trajectory of a MO in a CA of length L: • the global trajectory of a MO in different CAs:
Graphs of Cellular Automata Model (GCA) • Moving rules: Po
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Trajectory Prediction • The Linear Prediction (LP) • the trajectory function for an object between time t0 and t1 • basic LP idea • the inadequacy of LP
Trajectory Prediction • The Simulation-based Prediction (SP) • Get the predicted positions by simulating a object • Get the future trajectory function of a MO from the points using regression (OLSE)
Trajectory Prediction • Get the slowest and the fastestmovement function by using different Pd • Find the bounds of future positions by translating the 2 regression lines
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Experimental Evaluation • Datasets: generated by: CA simulator Brinkhoff’s Network-based Generator • Prediction Accuracy with Different Threshold
Experimental Evaluation • Prediction Accuracy with Different Pd
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Conclusion • introduce a new model - GCA • propose a prediction method, based on the GCA • experiments show higher performacne than linear prediction
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Relation to our Project • Common: • Modeling road network constrained MOs • Tracking the movement of MOs • Difference: • efficiently perform query on MOs in oracle in my project • an option to use non-linear predition strategy • an idea to consider the uncertainty of MO.
Outline • Introduction • Related Work • Graphs of Cellular Automata Model (GCA) • Trajectory Prediction • Experimental Evaluation • Conclusion • Relation to our Project • Strong and Weak Points
Strong and Weak Points • Strong Points • integrate traffic simulation techniques with dbs model • propose a GCA model • take correlation of MOs and stochastic hehavior into account • Weak Points • a non-trival prediction strategy • inconsistent position representation. (ti, di) and (ti, li) • typoes: