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Transfer Learning Approach for Railway Technical Map (RTM) Component Identification

Rumalshan, Obadage Rochana, Weerasinghe, Pramuka, Shaheer, Mohamed, Gunathilake, Prabhath, Dayaratna, Erunika

arXiv.org Artificial Intelligence

Railway Transportation is extremely popular all around the globe and urges the requirement of digitized databases that includes railway track information with all railway track components such as signals, switches and mileposts (Figure 1). A Railway Technical Map (RTM) is a complex diagram (Figure 1) which includes all the information associated with a railway track. At present, most railway companies maintain RTMs designed with computer aided software, yet they are only available in PDF format. These contain partially distorted map components where identifying those components using basic digital image processing techniques is hard due to its complexity. This work focuses on implementing an automated system to generate CSV formatted files for given RTM input images containing all the digitized data that can be used with further decision support tools. The final formatted text will include the component associativity with mileposts, component names and descriptions.


Inferring Heterogeneous Treatment Effects of Crashes on Highway Traffic: A Doubly Robust Causal Machine Learning Approach

Li, Shuang, Pu, Ziyuan, Cui, Zhiyong, Lee, Seunghyeon, Guo, Xiucheng, Ngoduy, Dong

arXiv.org Machine Learning

Highway traffic crashes exert a considerable impact on both transportation systems and the economy. In this context, accurate and dependable emergency responses are crucial for effective traffic management. However, the influence of crashes on traffic status varies across diverse factors and may be biased due to selection bias. Therefore, there arises a necessity to accurately estimate the heterogeneous causal effects of crashes, thereby providing essential insights to facilitate individual-level emergency decision-making. This paper proposes a novel causal machine learning framework to estimate the causal effect of different types of crashes on highway speed. The Neyman-Rubin Causal Model (RCM) is employed to formulate this problem from a causal perspective. The Conditional Shapley Value Index (CSVI) is proposed based on causal graph theory to filter adverse variables, and the Structural Causal Model (SCM) is then adopted to define the statistical estimand for causal effects. The treatment effects are estimated by Doubly Robust Learning (DRL) methods, which combine doubly robust causal inference with classification and regression machine learning models. Experimental results from 4815 crashes on Highway Interstate 5 in Washington State reveal the heterogeneous treatment effects of crashes at varying distances and durations. The rear-end crashes cause more severe congestion and longer durations than other types of crashes, and the sideswipe crashes have the longest delayed impact. Additionally, the findings show that rear-end crashes affect traffic greater at night, while crash to objects has the most significant influence during peak hours. Statistical hypothesis tests, error metrics based on matched "counterfactual outcomes", and sensitive analyses are employed for assessment, and the results validate the accuracy and effectiveness of our method.


New Perspectives on the Use of Online Learning for Congestion Level Prediction over Traffic Data

Manibardo, Eric L., Laña, Ibai, Lobo, Jesus L., Del Ser, Javier

arXiv.org Machine Learning

This work focuses on classification over time series data. When a time series is generated by non-stationary phenomena, the pattern relating the series with the class to be predicted may evolve over time (concept drift). Consequently, predictive models aimed to learn this pattern may become eventually obsolete, hence failing to sustain performance levels of practical use. To overcome this model degradation, online learning methods incrementally learn from new data samples arriving over time, and accommodate eventual changes along the data stream by implementing assorted concept drift strategies. In this manuscript we elaborate on the suitability of online learning methods to predict the road congestion level based on traffic speed time series data. We draw interesting insights on the performance degradation when the forecasting horizon is increased. As opposed to what is done in most literature, we provide evidence of the importance of assessing the distribution of classes over time before designing and tuning the learning model. This previous exercise may give a hint of the predictability of the different congestion levels under target. Experimental results are discussed over real traffic speed data captured by inductive loops deployed over Seattle (USA). Several online learning methods are analyzed, from traditional incremental learning algorithms to more elaborated deep learning models. As shown by the reported results, when increasing the prediction horizon, the performance of all models degrade severely due to the distribution of classes along time, which supports our claim about the importance of analyzing this distribution prior to the design of the model.