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1 Modeling Evolution in Spatial Datasets Paul Amalaman 2/17/2012 Dr Eick Christoph Nouhad Rizk Zechun Cao Sujing Wang Data Mining and Machine Learning Lab Team Members Anirup Dutta Swati Goyal Tarikul Islam Paul Amalaman
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I- Background II-Research Goals III-Case Study IV-Summary 2
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Machine Learning Techniques are mostly used where modeling implicit trends is possible (Regression) stable patterns exist in dataset (Classification) Simulation Systems are used when a model is hard to establish there is a great degree of randomness in the attribute values there are a lot of interactions between objects when attributes have to be predicted recursively over many steps Example Applications of Simulation Systems: Traffic Modeling, Weather Forecasting, Social Networks, Urban Modeling 3 I-Background
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I-Background continued(3) Spatial Simulation Systems Cellular Automata (CA) (Cell centered approach) Continuous Agent Space Or Multi Agent System (MAS) (Agent centered approach) ABM 4
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Concept of neighborhood Moore Neighborhood Von Newman neighborhood Moore Neighborhood http://en.wikipedia.org/wiki/Moore_neighborhood Von Newman Neighborhood http://en.wikipedia.org/wiki/Von_Neumann_neighborhood 5 D(x-1,y-1)D(x-1,y)D(x+1,y-1) D(x-1,y)P(x,y)D(x+1,y) D(x-1,y+1) D(x+1,y+1) D(x-1,y) P(x,y)D(x+1,y) D(x-1,y+1) I-Background continued(3) Modeling with Cellular Automata
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I-Background continued(4) Modeling with Cellular Automata Cellular Automata provides the programmer a cell-centered programming style where the set of cells represents computing units that are regularly organized good efficiency with parallel architecture 6
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II-Research Goals Using Data Mining and Machine Learning Techniques to Enhance Simulation Systems New approach= Machine Learning Techniques + Spatial Simulation Systems Goal1: Grid-based Models for Progression in Spatial Datasets Goal2: Development of Cluster-based Bias Removal Methods 7
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8 ? y i,j,t+1 = f ij (x 1,1,1,t,…, x 1,n,n,t,…, x m,1,1,t,…, x m,n,n,t, y 1,1,t,…,y,n,n,t ) II-Research Goal continued (1) Goal1:Grid-based Models for Progression in Spatial Datasets t t +1 X1(t) X2(t). Xn(t) Y(t) X1(t+Δt)=? X2(t+Δt)=?. Xn(t+Δt)=? Y(t+Δt)=? Given that at t we know all the attribute values including the output variable Y, can we predict all attribute values at t+1? Challenges: 1. Many target variables to predict; different variables have to be predicted at different location 2. Target variables are not independent of each other (e.g. some are auto-correlated) 3. Models has to be used over multiple steps
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EPA prediction models are meteorological and chemical transport models. Those models are derived from solving differential equations. Over time, the model bias grows larger http://www.epa.gov/AMD/CMAQ/ch06.pdf 9 II-Research Goal continued (2) Goal2:Development of Cluster-based Bias Removal Methods Model Output + bias b(x) Input x Whether pattern recognition Model Output Correction (bias removal) Input x Output h(b(x), group(x)) Bias removal based on whether pattern recognition Our model, model h learn group(x), and b(x) and make better prediction b(x) group(x)
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III-Case Study Improving Ozone Forecasting For Houston- Galveston Area Goal1: Development of a Grid-based Prediction Framework Goal2: Development of Cluster-based Bias Removal Methods In Collaboration with UH-IMAQS Institute for Multidimensional Air Quality Studies (UH Department of Earth and Atmospheric Science) -Dr Rappenglueck, Bernhard -Dr Li, Xiangshang 10
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III-Case Study Continued(1) Ozone Prediction Goal 1:Improving Prediction for Spatial Progression Given what happened at t, can we predict what happens at t+Δ, t+2Δ,..? 11
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Goal 2- Improving forecast Accuracy 12 III-Case Study Continued(2) Ozone Prediction
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III-Case Study Continued(2) Status of Dissertation Methods to collect ozone data and to capture it in a relational database have been developed. The necessary knowledge for simulation- based prediction systems in general, and ozone prediction in particular has been obtained Started work on different modeling approaches for grid-based prediction 13
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IV-SUMMARY 14
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Thank you! 15
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