Academic Publications

Qin, H., Zaman, A.F., Jain, S., Wang, X., Liu, X. (2026). Artificial intelligence aided detection and analysis of vehicular stop on track at railroad grade crossings. Smart and Resilient Transportation, 8(1), 2-23.

Wang, X., Dai, J., Liu, X. (2025). A spatial-temporal neural network based on ResNet-Transformer for predicting railroad broken rails. Advanced Engineering Informatics, 65, 103126.

Kang, D., Zhao, J., Dick, C.T., Liu, X., Lin, C.Y., Bian, Z., Kirkpatrick, S.W. (2024). Quantifying the influence of tank car position and train configuration on the risk of rail transport of class 3 flammable liquids. Transportation Research Record, 03611981241274649.

Kang, D., Dai, J., Liu, X., Bian, Z., Zaman, A., Wang, X. (2024). Estimating the occurrence of broken rails in commuter railroads with machine learning algorithms. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 09544097241280848.

Wang, X., Liu, X., Bai, Y. (2024). Prediction of the temperature of diesel engine oil in railroad locomotives using compressed information-based data fusion method with attention-enhanced CNN-LSTM. Applied Energy, 367, 123357.

Kang, D., Kirkpatrick, S. W., Zhang, Z., Liu, X., Bian, Z. (2024). Freight train derailment severity prediction: a physics-informed one-dimensional model. Smart and Resilient Transportation.

Wang, X., Bai, Y., Liu, X. (2023). Prediction of railroad track geometry change using a hybrid CNN-LSTM spatial-temporal model. Advanced Engineering Informatics, 58, 102235.

Wang, Z., Shlake, B.W., Mulay, N., Zaman, A., Liu, X. (2023). Development and Testing of A UWB-based Vehicle-to-Vehicle (V2V) Ranging System for Self-Propelled Rail Vehicles. IEEE Transactions on Vehicular Technology.

Li, W., Bian, Z., Liu, X. (2023). Statistical Analysis of Train Derailment Severity for Unit Trains Versus Manifest Trains. Transportation Research Record, 03611981231182989.

Zhu, Y., Ni, K., Li, X., Zaman, A., Liu, X., Bai, Y. (2023). Artificial Intelligence Aided Crowd Analytics in Rail Transit Station. Transportation Research Record, 03611981231175156.

Zaman, A., Huang, Z., Li, W., Qin, H., Kang, D., Liu, X. (2023). Artificial Intelligence-Aided Grade Crossing Safety Violation Detection Methodology and a Case Study in New Jersey. Transportation Research Record, 03611981231163824.

Qin, H., Zaman, A., Liu, X. (2023). Artificial intelligence-aided intelligent obstacle and trespasser detection based on locomotive-mounted forward-facing camera data. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 09544097231156312.

Kang, D., Zhao, J., Dick, C.T., Liu, X., Bian, Z.Y., Kirkpatrick, S.W., Lin, C.Y. (2023). Probabilistic risk analysis of unit trains versus manifest trains for transporting hazardous materials. Accident Analysis and Prevention, 181, 106950.

Wang, X., Liu, X., Euston, T.L. (2023). Relationship between track geometry defect occurrence and substructure condition: A case study on one passenger railroad in the United States. Construction and Building Materials, 365, 130066.

Dai, J., Liu, X. (2022). Machine learning based prediction of rail transit signal failure: A case study in the United States. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 09544097221127781.

Wang, Z., Liu, X. (2022). Cyber security of railway cyber-physical system (CPS) – A risk management methodology. Communications in Transportation Research, 2, 100078.

Wang, X., Liu, X., Bian, Z. (2022). A machine learning based methodology for broken rail prediction on freight railroads: A case study in the United States. Construction and Building Materials, 346, 128353.

Song, B., Zhang, Z.P., Qin, Y., Liu, X., Hu, H. (2022). Quantitative analysis of freight train derailment severity with structured and unstructured data. Reliability Engineering & System Safety, 108563.

Zhang, Z.P., Lin, C.Y., Liu, X., Bian, Z.Y., Dick, C.T., Zhao, J.X., Kirkpatrick, S. (2022). An Empirical analysis of freight train derailment rates for unit trains and manifest trains. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 236(10), 1168-1178.

Bian, Z.Y., Bai, Y., Liu, X., Wang, B.J. (2022). An online hybrid mechanism for dynamic first-mile ridesharing service. Transportation Research Part C, 138, 103585.

Bian, Z.Y., Bai, Y., Douglas, W.S., Liu, X. (2022). Multi-year planning for optimal navigation channel dredging and dredged material management. Transportation Research Part E, 159, 102618.

Zhang, Z.P., Zaman, A., Xu, J.X., Liu, X. (2022). Artificial intelligence-aided railroad trespassing detection and data analytics: Methodology and a case study. Accident Analysis & Prevention, 168, 106594.

Dick, C.T., Zhao, J., Liu, X., Kirkpatrick, S.W. (2021). Quantifying Recent Trends in Class 1 Freight Railroad Train Length and Weight by Train Type. Transportation Research Record, 03611981211031534.

Zhang, Z.P., Liu, X., Hu, H. (2021). Passenger rail station safety improvement and analysis of end-of-track collisions based on systems-theoretic accident modeling and processes (STAMP). Smart and Resilient Transport.

Zhang, Z.P., Liu, X., Hu, H. (2021). Statistical Analysis of Seasonal Effect on Freight Train Derailments. Journal of Transportation Engineering, Part A: Systems, 147(10), 04021073.

Wang, Y., Wang, P., Tang, H.Y., Liu, X., Xu, J.H., Xiao, J.L., Wu, J.S. (2021). Assessment and prediction of high speed railway bridge long-term deformation based on track geometry inspection big data. Mechanical Systems and Signal Processing, 158, 107749.

Zhang, Z.P., Turla, T., Liu, X. (2020). Analysis of human-factor-caused freight train accidents in the United States. Journal of Transportation Safety & Security (in press).

Zhang, Z.P., Liu, X. (2020). Safety risk analysis of restricted-speed train accidents in the United States. Journal of Risk Research. https://doi.org/10.1080/13669877.2019.1617336.

Wang, Y., Cong, J.L., Wang, P., Liu, X., Tang, H.H. (2020). A data-fusion approach for speed estimation and location calibration of a metro train based on low-cost sensors in smartphones. IEEE Sensors Journal, 19(22): 10744-10752.

Tang, H.Y., Wang, Y., Liu, X., Feng, X.X. (2020). A Double-Switch-Q-network-based reinforcement learning approach for optimal control of multiple electric locomotives in a heavy-haul freight train. Knowledge-based System (in press).

Jing, G.Q., Dong, D., Liu, X. (2019). High-speed railway ballast flight mechanism analysis and risk management – A literature review. Construction and Building Materials 233: 629-642.

Zaman, A., Ren, B.Z., Liu, X. (2019). Artificial-intelligence-aided automated detection of railroad trespassing. Transportation Research Record: Journal of the Transportation Research Board.

Zhang, Z.P., Liu, X., Holt, K. (2019). Prevention of end-of-track collisions at passenger terminals via positive train control. Transportation Research Record: Journal of the Transportation Research Board.

Wang, Y., Tang, H.Y., Wang, P., Liu, X., Chen, R. (2019). Multipoint chord reference system for track irregularity: part I - theory and methodology. Measurement, 138: 240-255.

Wang, Y., Tang, H.Y., Wang, P., Liu, X., Chen, R. (2019). Multipoint chord reference system for track irregularity: part II - numerical analysis. Measurement, 138: 194-205.

Bian, Z.Y., Liu, X. (2019). Mechanism design for first-mile ridesharing based on personalized requirements part II: solution algorithm for large-scale problems. Transportation Research Part B - Methodological, 120: 172-192.

Bian, Z.Y., Liu, X. (2019). Mechanism design for first-mile ridesharing based on personalized requirements part I: theoretical analysis in generalized scenarios. Transportation Research Part B - Methodological, 120: 147-171.

Zhang, Z.P., Liu, X.. (2018). Safety risk analysis of restricted-speed train accidents in the United States. (in press).

Bullough, J., Liu, X. (2018). Assessing the visibility of raised pavement markers and alternative forms of delineation. (in press).

Ma, X.P., Dong, H.H, Li, P., Jia, L.M., Liu, X., Qin, Y., Tang, J.Q. (2018). Adaptive optimization of multi-hop communication protocol for linear wireless monitoring networks on high-speed railways. IEEE Transactions on Intelligent Transportation Systems. (accepted).

Song, L., Chen, J.H., Li, K., Liu, X., Fei, Y., Yu, H. (2018). Periodical characteristics of ship building market activity: a wavelet analysis. Journal of Marine Science and Technology. (in press).

Zhang, Z.P., Trivedi, C.B., Liu, X. (2018). Automated detection of grade-crossing-trespassing near misses based on computer vision analysis of surveillance video data. Safety Science, 110(B): 276-285.

Turla, T., Liu, X., Zhang, Z.P. (2018). Analysis of freight train collision risk in the United States. Proc IMechE Part F: J Rail and Rapid Transit, 0(0): 1–14.

Zaman, A., Liu, X., Zhang, Z.P. (2018). Video analytics for railroad safety research: an artificial intelligence approach. Transportation Research Record: Journal of the Transportation Research Board, 00(0): 1–9.

Wang, Y., Wang, P., Wang, X., Liu, X. (2018). Position synchronization for track geometry inspection data via big-data fusion and incremental learning. Transportation Research Part C, 93: 544-565.

Deng, J.Y., Liu, X., Jing, G.Q., Bian, Z.Y. (2018). Probabilistic risk analysis of flying ballast hazard on high-speed rail lines. Transportation Research Part C, 93: 396–409.

Bian, Z.Y., Liu, X. (2018). A real time adjustment strategy for operational-level stochastic orienteering problem: a simulation-aided optimization approach. Transportation Research Part E, 115: 246–266.

He, Q., Ghofrani, F., Goverde, R., Liu, X. (2018). Recent applications of big data analytics in railway transportation systems: a survey. Transportation Research Part C, 90: 226–246.

Ma, X.P., Dong. H.H., Li, P., Jia, L.M., Liu, X. (2018). A multi-service train-to-ground bandwidth allocation strategy based on game theory and particle swarm optimization. IEEE Intelligent Transportation Systems Magazine, 10(3): 68-79.

Ma, X.P., Dong, H.H., Jia, L.M., Liu, X., Xie, G., Bian, Z.Y. (2018). An optimal communications protocol for maximizing lifetime of railway infrastructure wireless monitoring network. IEEE Transactions on Industrial Informatics, 14(8): 3347-3357.

Zhang, Z.P., Liu, X. (2018). Positive Train Control (PTC) for railway safety in the United States: policy developments and critical issues Utilities Policy, 51: 33-40.

Zhou, K., Chen. J.H., Liu, X. (2018). Optimal collision-avoidance maneuvers to minimize bunker consumption under the two-ship crossing situation. Journal of Navigation, 71: 151–168.

Higgins, C., Liu, X. (2018). Modeling of track geometry degradation and decisions on safety and maintenance: a literature review and possible future research directions. Proc IMechE Part F: J Rail and Rapid Transit, 232(5): 1385–1397.

Liu, X., Turla, T., Zhang, Z.P. (2018). Accident-cause-specific risk analysis for rail transport of hazardous materials. Transportation Research Record, 00(0): 1–12.

Chen, J., Notteboom, T., Liu, X., H., Nikitakos, N., Yang, C. (2017). The Nicaragua Canal: potential impact on international shipping and its attendant challenges. Maritime Economics & Logistics, 1-20.

Liu, X., Liu, C., Hong, Y.L. (2017). Analysis of multiple tank car releases in train accidents. Accident Analysis and Prevention, 107: 164–172.

Chen, J., Liu, K.X., Liu, X., Li, H. (2017). The development of ship registration policy in china: Response to flags of convenience. Marine Policy, 83: 22-28.

Liu, X., Bai, Y., Chen, J.H. (2017). An intermodal transportation geospatial network modeling for containerized soybean shipping. Journal of Ocean Engineering and Science, 2(2): 143-153.

Yue, Y.X., Han, J., Wang, S.F., Liu, X. (2017). Integrated train timetabling and rolling stock scheduling model based on time-dependent demand for urban rail transit. Computer-Aided Civil and Infrastructure Engineering, 32: 856-873.

Bai, Y., Liu, X., Higgins, C., Chiu, Y.P., Chen, J.H. (2017). Transportation cost modeling of containerized soybean exports in the United States. Transportation Research Record: Journal of the Transportation Research Board, 2611: 19-31.

Liu, X. (2017). Optimizing rail defect inspection frequency to reduce the risk of hazardous materials transportation by rail. Journal of Loss Prevention in the Process Industries, 48: 151-161.

Chen. J.H., Liu, X., Zhang. X.H., He, J.L., Luo, L.H. (2017). Optimal bilateral cooperative slot allocation for two liner carriers under a co-chartering agreement. Journal of Navigation, 70: 1170–1182.

Liu, X. (2017). Risk comparison of transporting hazardous materials in unit trains versus mixed trains. Transportation Research Record: Journal of the Transportation Research Board, 2608. 134–142.

Liu, X.,Saat, M.R., Barkan, C.P.L. (2017). Freight-train derailment rates for railroad safety and risk analysis. Accident Analysis and Prevention, 98: 1-9.

Liu, X.,Schlake, B. (2016). Derailment risk analysis of liquefied natural gas (LNG) tenders on mainline freight trains in the United States. Transportation Research Part C –Emerging Technologies, 72: 77-92.

Liu, X. (2016). Statistical causal analysis of freight train derailments in the United States. Journal of Transportation Engineering Part A: Systems, 143(2): 04016001-7.

Liu, X. (2016). Analysis of collision risk for freight trains in the United States. Transportation Research Record - Journal of the Transportation Research Board, 2546: 121-128.

Lin, Y., Bian, Z.Y., Liu, X. (2016). Developing a dynamic neighborhood structure for an adaptive hybrid simulated annealing - tabu search algorithm to solve the symmetrical traveling salesman problem. Journal of Applied Soft Computing, 49: 937-952.

Liu, X. (2016). Risk analysis of transportation crude oil by rail: methodology and decision support system. Transportation Research Record - Journal of the Transportation Research Record, 2547: 57–65.

Liu, X., Dick, C.T. (2016). Risk-based optimization of rail defect inspection frequency for petroleum crude oil transportation. Transportation Research Record - Journal of the Transportation Research Board, 2545: 27–35.

Liu, X., Hong, Y. (2015). Modeling railroad tank car releases using a generalized binomial model. Accident Analysis and Prevention, 84: 20-26.

Liu, X. (2015). Statistical temporal analysis of freight-train derailment rates in the United States: 2000 to 2012. Transportation Research Record, 2476: 119-125.

Liu, X., Lovett, A., Dick, C.T., Saat, M.R., Barkan, C.P.L. (2014). Optimization of rail defect inspection frequency for the improvement of railway transportation safety and efficiency. Journal of Transportation Engineering, 140(10): 04014041-8.

Liu, X., Saat, M.R., Barkan, C.P.L. (2014). Probability analysis of multiple-tank-car release incidents in railway hazardous materials transportation. Journal of Hazardous Materials, 276: 442-451.

Liu, X., Saat, M.R., Qin, X., Barkan, C.P.L. (2013). Analysis of U.S. freight-train derailment severity using zero-truncated negative binomial regression and quantile regression. Accident Analysis and Prevention, 59: 87–93.

Liu, X., Saat, M.R., Barkan, C.P.L. (2013). Integrated risk reduction framework to improve railway hazardous materials transportation safety. Journal of Hazardous Materials, 260: 131-140.

Liu, X., Saat, M.R., Barkan, C.P.L. (2013). Safety effectiveness of integrated risk reduction strategies for rail transport of hazardous materials. Transportation Research Record - Journal of the Transportation Research Board, 2374: 102-110.

Liu, X., Saat, M.R., Barkan, C.P.L. (2012). Analysis of causes of major train derailment and their effect on accident rates. Transportation Research Record - Journal of the Transportation Research Board, 2289: 154-163.

Liu, X., Barkan, C.P.L., Saat, M.R. (2011). Analysis of derailments by accident cause: evaluating railroad track upgrades to reduce transportation risk. Transportation Research Record - Journal of the Transportation Research Board, 2261: 178-185.

Jablonski, M., Wang, Y.X., Yavvari, C., Liu, X., Holt. K., Wijesekera, D. (2019). AFTeR: Attack-fault and reliability modeling of movable railroad bridge systems. AREMA Annual Conference.

Wang, Z.Z.*, Liu, X., Sykes, B., Wijesekera, D. (2019). Simulation-based analysis for traffic disruptions caused by DoS attacks to Railroad Cyber-Physical System. AREMA Annual Conference.

Zhang, Z.P.*, Liu, X., Holt, K. (2019). Prevention of end-of-track collisions in passenger terminals via Positive Train Control: a benefit-cost analysis. AREMA Annual Conference.

Zhang, Z.P.*, Casazza, A.*, Turla, T.*, Liu, X. (2019). Railroad trespassing risk management: a literature review. AREMA Annual Conference.

Wang, Z.Z.*, Sykes, B., Holt, K., Wang, Y.X., Yavvari, C., Jablonski, M., Wijisekera, D., Liu, X. (2019). Cyber security analysis for advanced train control system (ATCS) In CTC systems: concepts and methods. Joint Rail Conference.

Wang, Y.X., Jablonski, M., Yavvari, C., Wang, Z.Z., Liu, X., Holt, K., Wijisekera, D. (2019). Safety and security analysis of moveable railroad bridges. Joint Rail Conference.

Zhao, H., Yue, Y., Liu, X. (2018). Freight railroad network blocking problem: modeling, formulation and improved particle swarm optimization algorithm. International Conference on Intelligent Rail Transportation (ICIRT).

Wang, Y.*, Tang, H.Y.*, Liu, X., Gao, T. C., Wang, P. (2018). Data fusion approach for speed estimation and location calibration of a metro train based on low-cost sensors in smartphones. Annual Meeting of Transportation Research Board.

Zhang, Z.P.*, Liu, X., Holt, K. (2018). Prevention of end-of-track collisions at passenger terminals via positive train control. Annual Meeting of Transportation Research Board.

Turla, T.*, Liu, X., Zhang, Z.P.* (2018). Safety risk analysis of human-factor-caused freight train accidents in the United States. Annual Meeting of Transportation Research Board.

Zhou, K.*, Liu, X., Shah, K.* (2018). Big-data-aided rail defect risk prediction using machine learning algorithms. AREMA Annual Conference.

Zhang, Z.P.*, Liu, X., Holt, K. (2018). Analysis of restricted speed accidents and potential implementation of positive train control system. AREMA Annual Conference.

Liu, X., Bian, Z.Y.*, Wijesekera, D., Holt, K. (2018). Cyber security risk management of connected railroads: a literature review and industry survey. AREMA Annual Conference.

Zhang, Z.P.*, Liu, X., Bian, Z.Y.* (2018). Analysis of restricted speed related train accidents in the United States, 2000 to 2016. Joint Rail Conference.

Ma, X.P.*, Dong, H.Z.,Liu, X., Jia, L.M. (2018). Lifetime maximization by optimizing the computation/communication strategy for railway wireless monitoring system. Joint Rail Conference.

Zhang, Z.P.*,Liu, X., Bian, Z.Y.* (2018). Analysis of restricted speed accidents using fault tree analysis. Joint Rail Conference.

Milo, D.*, Principe, L.*,Liu, X., Zhou, K.*, Deng, J.Y.* (2018). A literature review of rail defect causal factors. Joint Rail Conference.

Turla, T.* Liu, X., Zhang, Z.P.*, Bian. Z.Y.* (2018). Analysis of train collision frequency and severity in the United States. Joint Rail Conference.

Bian, Z.Y.*, Liu, X. (2018). A detour-based pricing mechanism for first-mile ridesharing in connection with rail public transit. Joint Rail Conference.

Bullough, J., Liu, X. (2018). Luminance measurement and visual performance analyses of raised pavement markers. Annual Meeting of Transportation Research Board.

Cui, N., Kroon, A., Muthumani, A., Liu, X. (2018). Refining return on investment methodology/tool for MnPASS Part I: literature review. Annual Meeting of Transportation Research Board.

Chen, Z., Qin, X., Liu, X., Shaon, M.R. (2018). A spatial hurdle crash prediction model: analyzing the correlation between dual states. Annual Meeting of Transportation Research Board.

Zaman, A.*, Liu, X., Zhang, Z.P.* (2018). Video analytics for railroad safety research: an Artificial Intelligence approach. Annual Meeting of Transportation Research Board.

Liu, X., Turla, T.*, Zhang. Z.P.*.(2018). Effect of accident cause on the transport risk of hazardous materials by rail. Annual Meeting of Transportation Research Board.

Zhang, Z.P.*, Qin, X., Liu, X. (2018). Statistical analysis of seasonal effect on freight railroad derailment rate. Annual Meeting of Transportation Research Board. Annual Meeting of Transportation Research Board.

Wang, Z., Saat, M.R., Barkan, C.P.L., Liu, X. (2017). Principal factors contributing to heavy haul freight train safety improvements in North America: a quantitative analysis. International Heavy Haul Association Conference, Cape Town, South Africa.

Wang, Z., Saat, M.R., Barkan, C.P.L., Liu, X. (2017). Trends in U.S. freight train accident causes and rates: a quantitative approach. Proceedings of Annual Meeting of Transportation Research Board, Washington, D.C.

Yue, Y., Han, J., Wang, S., Liu, X. (2017). Integrated train timetabling and rolling stock scheduling model based on time-dependent demand for urban rail transit. Transportation Research Board Annual Meeting, Washington D.C.

Deng, J.Y., Jing, G.Q., Liu, X. (2017). Probabilistic analysis of flying ballast on high speed rail lines. Joint Rail Conference, Philadelphia, PA.

Liu, X. (2017). Risk comparison of transporting hazardous materials in unit trains versus mixed trains. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Liu, X., Rodriguez, D. (2017). Statistical comparison of train accident rates: methodology and decision support tool. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Zhou, K., Liu, X., Zhou, Y. (2017). Prioritization of rail defect inspection: a risk-based optimization approach. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Zhou, K., Liu, X. (2017). Risk-informed ultrasonic rail defect inspection frequency optimization. Joint Rail Conference, Philadelphia, PA.

Liu, X., Dick. C.T. (2016). Risk-based optimization of rail defect inspection frequency for petroleum crude oil transportation. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Liu, X. (2016). Collision risk analysis of freight railroads in the United States, 2000 to 2014. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Liu, X. (2016). Risk analysis of transporting crude oil by rail: methodology and decision support system. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Zhou, K., Chen, J.H., Liu, X. (2016). Risk-based ship collision-avoidance maneuvers under the optimal fuel use. Proceedings of Annual Meeting of Transportation Research Board, Washington D.C.

Wang, Y.L., Liu, X. (2016). Risk Analysis of U.S. Freight-Train Collisions 2000 to 2014. Joint Rail Conference, Columbia, South Carolina (under review).

Hu, C., Liu, X. (2016). Modeling track geometry degradation using data mining techniques. Joint Rail Conference, Columbia, South Carolina (under review).

Ma, L., Liu, X. (2016). Spatial risk analysis of U.S. freight-train derailments. Joint Rail Conference, Columbia, South Carolina (under review).

Liu, X., Qin, Y.B. (2016). Scheduling of rail defect inspection and repair using simulation-based risk analysis. Joint Rail Conference, Columbia, South Carolina (under review).

Ben-Gera, T., He, J.B., Liu, X. (2016). Modeling broken rail caused derailment risk. Joint Rail Conference, Columbia, South Carolina (under review).

He, J.B., Ben-Gera, T., Liu, X. (2016). Modeling track geometry defect caused derailment risk. Joint Rail Conference, Columbia, South Carolina (under review).

Liu, X., 2015. Statistical temporal analysis of freight-train derailment rates in the United States: 2000 to 2012. Proceedings of 94th Annual Meeting of Transportation Research Board, Washington D.C.

Liu, X., C.T. Dick, M.R. Saat, 2014. Optimizing the frequency of ultrasonic rail defect inspection to improve transportation safety and efficiency. Second Transportation and Development Institute (T&DI) Congress, Orlando, Florida.

Liu, X., M.R. Saat, C.P.L. Barkan, 2014. Optimization of rail defect inspection frequency to reduce railroad hazardous materials transportation risk. Proceedings of 93nd Annual Meeting of Transportation Research Board, Washington D.C.

Serrano, J.A., Liu, X., M.R. Saat, 2014. Methodology to evaluate the consequence of hazardous material releases from multiple tank cars involved in train accidents. Proceedings of 93nd Annual Meeting of Transportation Research Board, Washington D.C.

Liu, X., C.T. Dick, A. Lovett, M.R. Saat, C.P.L. Barkan, 2013. Seasonal effect on the optimization of rail defect inspection frequency. Proceedings of the American Society of Mechanical Engineers (ASME) Rail Transportation Division Fall Technical Conference, Altoona, Pennsylvania.

Liu, X., M.R. Saat, C.P.L. Barkan, 2013. Integrated risk management framework for improving the safety of hazardous materials transportation by rail. World Congress on Railway Research, Sydney, Australia.

Liu, X., M.R. Saat, C.P.L. Barkan, 2013. Safety effectiveness of integrated accident prevention strategies. Proceedings of the ASME-IEEE-ASCE-AREMA-TRB-APTA-INFORMS Joint Rail Conference. Knoxville, TN.

Liu, X., M.R. Saat, C.P.L. Barkan, 2013. Analysis of major derailment causes on heavy haul railways in the United States. International Heavy Haul Association Conference, New Delhi, India.

Liu, X., M.R. Saat, C.P.L. Barkan, 2013. Safety effectiveness of integrated risk reduction strategies for the transportation of hazardous materials by rail. Proceedings of 92nd Annual Meeting of Transportation Research Board, Washington D.C.

Liu, X., M.R. Saat, C.P.L. Barkan, 2013. A framework for evaluating cost-effectiveness of accident prevention strategies under uncertainty. Proceedings of 92nd Annual Meeting of Transportation Research Board, Washington D.C.

A. A. Shurpali, J.R. Edwards, R.G. Kernes, Liu, X., D.A. Lange, C.P.L. Barkan, 2013. Investigation of material improvements to mitigate the effects of abrasion mechanism of concrete crosstie rail seat deterioration (RSD). Proceedings of 92ndAnnual Meeting of Transportation Research Board, Washington D.C.

Liu, X., M.R. Saat, C.P.L. Barkan, 2011. Benefit-cost analysis of heavy haul railway track upgrade for derailment prevention. International Heavy Haul Association Conference, Calgary, Canada.

Liu, X., M.R. Saat, C.P.L. Barkan, 2010. Benefit-cost analysis of railway infrastructure improvement for derailment prevention. Proceedings of the ASME-IEEE-ASCE-AREMA-TRB Joint Rail Conference, Urbana, IL.

Wan, Z., Liu, X., 2009. Chinese railways transportation: opportunity and challenge. Proceedings of 88th Annual Meeting of Transportation Research Board, Washington D.C.

Barkan, C.P.L., Liu, X., Saat, M.R. (2015). Enhanced tank car design improves the safety of transporting crude oil and alcohol by rail. TR News, 41-43.

Chen, J.H., Liu, X. (2016). Nicaragua Canal may not benefit shipping. Nature 533, 321, doi:10.1038/533321d

Zaman, A., Ren B.Z., Liu, X. (2019). Artificial Intelligence–Aided Automated Detection of Railroad Trespassing. TR News, 30-35.