Bilkent University

Department of Computer Engineering

Ph.D DISSERTATION

COLLECTIVE DATA FORECASTING IN DYNAMIC TRANSPORT NETWORKS

Mehmet Güvercin

Ph.D Candidate

(Supervisor: Prof. Dr. İbrahim Körpeoğlu)

Assoc. Prof. Dr. Buğra GedikComputer Engineering Department

Bilkent University

Forecasting is a crucial tool for intelligent transportation systems and passengers of these systems and critical for transportation planning and management, as the transportation variable (e.g. delay,traffic speed) are among major costs in transportation. Each transportation variable may cause a further propagation in dynamic transport network. Hence, the transportation variable pattern of a node and the location of the node in the transport network can provide useful information for other nodes. We address the problem of forecasting transportation variable of a transport network node, utilizing the network information as well as the transportation variable patterns of similar nodes in the network. We propose ECFM, Exploratory Clustered Forecasting Modeling, on both static and dynamic transportation network which makes use of graph based features for time-series estimation. ECFM approach builds a representative timeseries for each group of nodes in the transport network and fits a common model like Seasonal Autoregressive Integrated Moving Average (SARIMA), Long-Short Term Memory (LSTM), Regression with Autoregressive Integrated Moving Average errors (REG-ARIMA), Regression with Long-Short Term Memory errors (REG-LSTM) for each, using the network based features as regressors. The models are then applied individually to each node data for predicting the node's transportation variable. We perform a network based analysis of the transport network and identify graph-based features and we represent nodes as vectors that are used for both grouping nodes and as regressors in forecasting models. We evaluate proposed ECFM, Exploratory Clustered Forecasting Modeling, on two datasets (flight delay dataset, traffic speed dataset). The experiments show that ECFM provides accurate forecasts of delays/traffics compared to individual forecasting models. Centrality measure of nodes such as betweenness centrality score is found to be an effective regressor in the clustered modeling. Clustered models built on dynamic networks performs better compared to static networks. ECFM, Exploratory Clustered Forecasting Modeling, is an conceptual approach and it is domain independent. Our proposed approach tries to incorporate information, related to estimated variable, exist in similar nodes of the network. Thus, we can achieve to build robust estimation models on enriched data.

DATE: 14 September 2021, Tuesday @ 16:40

PLACE: zoom