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Reachability-Based Confidence-Aware Probabilistic Collision Detection in Highway Driving

Wang, X. (author), Li, Zirui (author), Alonso-Mora, J. (author), Wang, Meng (author)

Risk assessment is a crucial component of collision warning and avoidance systems for intelligent vehicles. Reachability-based formal approaches have been developed to ensure driving safety to accurately detect potential vehicle collisions. However, they suffer from over-conservatism, potentially resulting in false–positive risk events in...

journal article 2024

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Condition monitoring of railway transition zones using acceleration measurements on multiple axle boxes: Case studies in the Netherlands, Sweden, and Norway

Wang, L. (author), Unsiwilai, S. (author), Zeng, Y. (author), Shen, C. (author), Hendriks, J.M. (author), Moraal, J. (author), Zoeteman, A. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

Railway transition zones connecting conventional embankments and rigid struc-tures, such as bridges and tunnels, usually degrade much faster than other railway sections. Efficient health condition monitoring of transition zones is important for preventative track maintenance. In this paper, a methodology for monitoring rail-way transition zones...

conference paper 2024

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Detection of Rail Surface Defects based on Axle Box Acceleration Measurements: A Measurement Campaign in Sweden

Phusakulkajorn, W. (author), Hendriks, J.M. (author), Moraal, J. (author), Shen, C. (author), Zeng, Y. (author), Unsiwilai, S. (author), Bogojevic, B. (author), Asplund, Matthias (author), Zoeteman, A. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

This work presents the results of a measurement campaign to demonstrate the effectiveness of the axle box acceleration (ABA) technology for detecting rail defects. The measurements were conducted along the Iron Ore line between Sweden and Norway for the IN2TRACK3 project. This line is mostly single-track with passenger-freight mixed traffic and...

conference paper 2024

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Vertical dynamic measurements of a railway transition zone: a case study in Sweden

Unsiwilai, S. (author), Shen, C. (author), Zeng, Y. (author), Wang, L. (author), Nunez, Alfredo (author), Li, Z. (author)

This study presents a measuring framework for railway transition zones using a case study on the Swedish line between Boden and Murjek. The final goal is to better understand the vertical dynamics of transition zones using hammer tests, falling weight measurements, and axle box acceleration (ABA) measurements. Frequency response functions ...

journal article 2024

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Multiple-axle box acceleration measurements at railway transition zones

Unsiwilai, S. (author), Wang, L. (author), Nunez, Alfredo (author), Li, Z. (author)

This paper presents a methodology for monitoring transition zones using responses of multiple-axle box acceleration (multi-ABA) measurements. The time–frequency characteristics of the vertical ABA signals from four wheelsets are analyzed. The major contributions are as follows. (1) We propose four key performance indicators (KPIs) to quantify...

journal article 2023

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Evaluating railway track stiffness using axle box accelerations: A digital twin approach

Shen, C. (author), Zhang, P. (author), Dollevoet, R.P.B.J. (author), Zoeteman, A. (author), Li, Z. (author)

While various train-borne techniques have been developed for measuring railway track stiffness, differentiating stiffness at different track layers remains a challenge. This study proposes a digital twin framework for the vehicle–track interaction system, which enables track stiffness evaluations based on axle box accelerations (ABA). The...

journal article 2023

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FLAIRS: FPGA-Accelerated Inference-Resistant & Secure Federated Learning

Li, H. (author), Rieger, Phillip (author), Zeitouni, Shaza (author), Picek, S. (author), Sadeghi, Ahmad Reza (author)

Federated Learning (FL) has become very popular since it enables clients to train a joint model collaboratively without sharing their private data. However, FL has been shown to be susceptible to backdoor and inference attacks. While in the former, the adversary injects manipulated updates into the aggregation process; the latter leverages...

conference paper 2023

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An experimental study on the effects of friction modifiers on wheel–rail dynamic interactions with various angles of attack

Yang, Z. (author), Zhang, P. (author), Moraal, J. (author), Li, Z. (author)

By modifying friction to the desired level, the application of friction modifiers (FMs) has been considered as a promising emerging tool in the railway engineering for increasing braking/traction force in poor adhesion conditions and mitigating wheel/rail interface deterioration, energy consumption, vibration and noise. Understanding the...

journal article 2022

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Multimodal dispersive waves in a free rail: Numerical modeling and experimental investigation

Zhang, P. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author)

In this paper, we present a solution method based on finite element (FE) modeling to predict multimodal dispersive waves in a free rail. As well as the modal behaviors and wavenumber-frequency dispersion relations, the phase and group velocities of six types of propagative waves are also derived and discussed in detail in the frequency range...

journal article 2021

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A Momentum-Guided Frank-Wolfe Algorithm

Li, Bingcong (author), Coutino, Mario (author), Giannakis, Georgios B. (author), Leus, G.J.T. (author)

With the well-documented popularity of Frank Wolfe (FW) algorithms in machine learning tasks, the present paper establishes links between FW subproblems and the notion of momentum emerging in accelerated gradient methods (AGMs). On the one hand, these links reveal why momentum is unlikely to be effective for FW-type algorithms on general...

journal article 2021

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Smart technology solutions for the NeTIRail-INFRA case study lines: Axle box acceleration and ultra-low cost smartphones

Nunez, Alfredo (author), Popa, Tudor (author), Anghel, Lucian Emmanuel (author), Hendriks, J.M. (author), Moraal, J. (author), Buretea, Laurentiu Dorin (author), Paragreen, Jon (author), Miron, Berbece (author), Gheorghe, Draghici (author), Campean, Mihail (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

In this paper, we present preliminary results on the development of smart technology solutions for lower density railway lines. The goal is to reach a cost effective inspection and asset management to minimize maintenance<br/>interventions time/cost without dedicated inspection vehicles. The proposed methods include axle box acceleration...

conference paper 2018

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A decision support approach for condition-based maintenance of rails based on big data analysis

Jamshidi, A. (author), Hajizadeh, S. (author), Su, Z. (author), Naeimi, M. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), De Schutter, B.H.K. (author), Li, Z. (author)

In this paper, a decision support approach is proposed for condition-based maintenance of rails relying on expert-based systems. The methodology takes into account both the actual conditions of the rails (using axle box acceleration measurements and rail video images) and the prior knowledge of the railway track. The approach provides an...

journal article 2018

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A condition-based maintenance methodology for rails in regional railway networks using evolutionary multiobjective optimization: Case study line Braşov to Zărneşti in Romania

Nunez, Alfredo (author), Jamshidi, A. (author), Wang, H. (author), Hendriks, J.M. (author), Ramirez Fonseca, I. (author), Moraal, J. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

In this paper, we propose a methodology based on signal processing and evolutionary multiobjective optimization to facilitate the maintenance decision making of infra-managers in regional railways. Using a train in operation (with passengers onboard), we capture the condition of the rails using Axle Box Acceleration measurements. Then, using...

conference paper 2018

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Corrosion Sensitivity of LED Packages

Jacobs, B.J.C. (author), van der Marel, C. (author), Lu, S.J. (author), Li, X.P. (author)

The penetration of solid state lighting applications is due to the promise of a low-cost reliable solution by means of application of low- and mid-power LEDs. These LED packages are manufactured by making use of new processes and materials which in principle introduces a series of known and unknown failure modes. Corrosion is a specific failure...

book chapter 2018

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Evaluating degradation at railway crossings using axle box acceleration measurements

Wei, Z. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

In this paper, we investigate the capability of an axle box acceleration (ABA) system to evaluate the degradation at railway crossings. For this purpose, information from multiple sensors, namely, ABA signals, 3D rail profiles, Global Positioning System (GPS) and tachometer recordings, was collected from both nominal and degraded crossings....

journal article 2017

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Health condition monitoring of insulated joints based on axle box acceleration measurements

Molodova, M. (author), Oregui Echeverria-Berreyarza, M. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

This paper presents a health condition monitoring system for insulated rail joints (IRJs) based on axle box acceleration (ABA) measurements. The ABA signals from all the wheels of the measuring train are processed to extract those characteristics that better represent the quality of the IRJ. Then, different indicators are used for damage...

journal article 2016

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Monitoring bolt tightness of rail joints using axle box acceleration measurements

Oregui Echeverria-Berreyarza, M. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author), Carroll, R (author), Dollevoet, R.P.B.J. (author)

Rail joints are a weak component in railway tracks because of the large impact and wheel-rail contact forces. Every train passage contributes to the deterioration of rail joints, causing visible (e.g. battered rails) and invisible (e.g. loose bolts) damages. The invisible damage cannot be detected by the commonly performed visual inspection,...

journal article 2016

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Key performance indicators using robust prediction modelling to consider squats in railway infrastructure

Jamshidi, A. (author), Nunez, Alfredo (author), Molodova, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

conference paper 2016

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Experimental Investigation Into the Condition of Insulated Rail Joints by Impact Excitation

Oregui, M. (author), Molodova, M. (author), Nunez, A. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

This paper presents a feasibility study to determine if the health condition of Insulated Rail Joints (IRJs) can be assessed by examining their dynamic response to impact excitation. First, a reference dynamic behavior is defined in the frequency domain of 50-1200 Hz based on field hammer test measurements performed on a IRJ baseline (i.e., a...

journal article 2015

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Automatic detection of squats in railway infrastructure

Molodova, M. (author), Li, Z. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author)

This paper presents an automatic method for detecting railway surface defects called “squats” using axle box acceleration (ABA) measurements on trains. The method is based on a series of research results from our group in the field of railway engineering that includes numerical simulations, the design of the ABA prototype, real-life...

journal article 2014