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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Damage evolution and cracking behaviors of hot reclaimed asphalt mixtures with high recycled asphalt pavement (RAP) content based on acoustic emission (AE) parameters and waveform characteristics</title>
      <link>https://trid.trb.org/View/2668744</link>
      <description><![CDATA[This paper investigated the damage evolution and cracking behaviors of hot reclaimed asphalt mixture (HRAM) with high recycled asphalt pavement (RAP) content by coupling acoustic emission (AE) parameters and waveform characteristics. Semi-circular bending (SCB) tests were conducted on HRAM containing RAP aged for 3, 5 and 10 years, with a virgin asphalt mixture (VAM) for comparison. The cracking resistance was quantified using fracture energy (Gf), while continuous damage progression and crack modes were revealed using AE energy, b-value and RA-AF parameters. Waveform-level analysis combining fast fourier transform (FFT), k-means and continuous wavelet transform (CWT) were employed to elucidate the transient failure mechanisms. Results demonstrate that HRAM exhibits superior initial cracking resistance than VAM, with Gf of 1377.2–1425.4 J/m² compared to 873.9 J/m² for VAM. However, HRAM experiences accelerated damage propagation and reduced deformation tolerance once crack initiates, manifested by abrupt and scattered high-energy AE bursts, whereas VAM displays continuous and progressive AE activity. The b-value evolution captures the transition from distributed crack accumulation to unstable catastrophic failure. RA-AF analysis reveals a stage-dependent cracking sequence evolving from mixed tensile-shear microcracking to shear-controlled macrocracking to ultimately tensile instability, with interfacial debonding identified as the dominant failure mechanism throughout the damage process. The time-frequency analysis shows that HRAM produces intermittent high-intensity AE signals with instantaneous frequency concentrated in 20–25 kHz band, associated with rapid microcrack coalescence and brittle fracture, while VAM exhibits low-intensity and continuous AE signals of ductile cracking. Overall, the combination of AE parameters and waveform characteristics enables a physically interpretable and quantitative framework for identifying cracking resistance degradation and diagnosing dominant failure modes in high-RAP content HRAM, which cannot be achieved using either approach alone.]]></description>
      <pubDate>Mon, 11 May 2026 08:50:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2668744</guid>
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    <item>
      <title>Comparison of Different Sounding Waveforms for a Wideband Correlation Channel Sounder</title>
      <link>https://trid.trb.org/View/2113822</link>
      <description><![CDATA[The fifth-generation (5G) mobile communication technology will be applied to the new generation wireless railway communication system, which introduces new frequency and bandwidth to channel measurement campaign and modeling. Accurate and efficient channel sounder is crucial for the channel measurement, channel modeling, and railway wireless communication systems optimization, while the characteristics of the sounder depend largely on the choice of the sounding waveform, especially in the high mobility scenario. However, the performance of sounder with different waveforms has not yet been sufficiently studied. This paper presents a comparison of different sounding waveforms for wideband correlation channel sounding application, which are pseudo-random noise (PN), Zadoff-Chu (ZC), chirp, and multi-tone, respectively. The wideband correlation channel sounder applys the software-defined radio (SDR) as the hardware platform. Waveform generation, channel sounder architecture, and performance comparison of waveforms are presented as well. Finally, system verification successfully prove that the wideband correlation channel sounder is able to measure CIRs accurately in terms of delay and power with large-range dynamic, which can be helpful for channel sounding of new generation wireless railway communication.]]></description>
      <pubDate>Mon, 30 Mar 2026 17:15:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2113822</guid>
    </item>
    <item>
      <title>Unimodular Complete Complementary Sequence With Optimal Trade-Off Between Auto- and Cross-Ambiguity Functions for MIMO Radars</title>
      <link>https://trid.trb.org/View/2598854</link>
      <description><![CDATA[It is difficult to design unimodular sequences with both good auto-ambiguity functions (AF) and cross-ambiguity functions (CAF), due to its nonconvex and higher cardinality property. To address this problem, we propose a Pareto optimization framework to reach an optimal tradeoff between AF and CAF. Besides, we also propose a novel convolution-based multi-objective optimization algorithm to optimize the conventional metrics including peak sidelobe level (PSL) and integrated sidelobe level (ISL). In this way, the generated sequences are Doppler resilient with the desired shape of aperiodic or periodic AFs. Compared with the state-of-the-art methods, simulation experimental results indicate the PSL metric of AF and CAF can be both suppressed to -72 dB under the same system parameters, obtaining a minimum of 7 dB gain.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:07:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2598854</guid>
    </item>
    <item>
      <title>Understanding Subterahertz Radio Channels: The Impact of Beamforming on Wireless System Design</title>
      <link>https://trid.trb.org/View/2601441</link>
      <description><![CDATA[Wireless connectivity in the subterahertz (sub-THz) band, spanning from 100 GHz to 300 GHz, is envisioned as an enhanced feature of 6G and beyond. Due to significant propagation losses at these frequencies, the transmission of sub-THz signals relies heavily on high antenna directivity, realized by beamforming. In this article, we present a newly developed sub-THz stored channel model, and perform a realistic evaluation of the impact of beamforming on sub-THz link establishment and data transmission. Unlike the propagation channel between the transmitting and receiving antennas, the radio channel is observed by a pair of beams. Incorporating the impact of beamforming into measured sub-THz propagation channel data enables to gain insights into the key factors that determine, among others, sub-THz beam alignment strategy and waveform design, ultimately enhancing spectral efficiency.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:07:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2601441</guid>
    </item>
    <item>
      <title>On the application of matching pursuit decomposition to jet noise data</title>
      <link>https://trid.trb.org/View/2617163</link>
      <description><![CDATA[The Matching Pursuit decomposition is a signal processing technique that projects a signal onto a linear expansion of waveforms selected from a redundant set of arbitrary functions, collectively referred to as a Dictionary. A key feature of this method is its ability to reconstruct a signal using a carefully chosen subset of these waveforms. In the present paper, this method is applied to illustrate its potentialities for reduced-order modeling of jet noise data. The analysis is conducted on an experimental dataset containing pressure time series taken in both the near- and far-field of a compressible subsonic free jet. For this application, the Dictionary is constructed using Gabor functions, and it is shown that even with a very limited number of atoms (one thousand), significant physical properties of the near pressure field are preserved. The results demonstrate that the effects of Mach number, as well as radial and axial distances from the jet exit, are accurately reproduced in both spectral features and temporal correlations. In the frequency domain, the energy bump at the Kelvin-Helmholtz frequency is effectively captured, primarily in the region close to the jet exit. Additionally, the non-zero correlations between near- and far-field pressure fluctuations are correctly captured, along with the corresponding phase lag obtained from the correlation maxima. The analysis confirms that the Matching Pursuit decomposition adaptively selects atoms that best represent the original signals. The superposition of a limited number of these optimally chosen atoms provides a highly simplified yet physically meaningful representation of the complex original signals. Future developments and applications aimed at modeling jet noise sources and predicting acoustic radiation are also outlined.]]></description>
      <pubDate>Tue, 25 Nov 2025 09:19:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617163</guid>
    </item>
    <item>
      <title>Research on the Physical Layer Diagnosis of an Ethernet-Based Train Communication Network</title>
      <link>https://trid.trb.org/View/2598876</link>
      <description><![CDATA[Ethernet technology is widely applied in train communication networks (TCNs), serving as a crucial foundation for the enhancement of train intelligence. However, with its extensive deployment, some reliability issues have been exposed, particularly those at the physical layer. Certain faults have significantly impacted the daily operations and services of trains. Focusing on the diagnosis of the health status of the Ethernet physical layer, this paper proposes a window-voting Support Vector Machine (SVM) classification method based on multi-feature fusion. It aims to identify various fault conditions in TCNs and to detect potential communication issues in advance. Initially, the specific problems in TCNs are analysed, examining data waveform characteristics under four health statuses: normal, interference, aging and fault. Subsequently, the weights of the waveform features are calculated using the Fuzzy Analytic Hierarchy Process and the Grey Relational Analysis method, and a window-voting SVM classifier is then constructed to categorize the data waveforms. Finally, a test system is set up in the laboratory to simulate different health statuses of the Ethernet physical layer, and to acquire experimental data for validating the effectiveness of the proposed method. The results show that the accuracy of recognizing the health status of the Ethernet physical layer exceeds.]]></description>
      <pubDate>Thu, 20 Nov 2025 17:07:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2598876</guid>
    </item>
    <item>
      <title>Wave finite element method for computing the dynamic response of periodic structures with transition zones and subjected to moving loads: Application to railways tracks with damaged or reinforced zones</title>
      <link>https://trid.trb.org/View/2549199</link>
      <description><![CDATA[The dynamics of transition zones linking two semi-infinite periodic structures is the subject of numerous researches, particularly in the railway track domain. For periodic structures, the Wave Finite Element (WFE) method is a numerical method helping the computation of the dynamics of these structures by reducing the consideration of the spatial domain to a few periods consisting of domains whose properties differ from those of the two right and left semi-infinite periodic structures. The WFE method firstly consists in reducing the degrees of freedom (DoFs) of one spatial period (substructure) to those of the borders of this substructure. Then, using the Floquet’s theorem, these DoFs are computed by the mean of a wave analysis. This article presents new developments in the Wave Finite Element (WFE) method to compute the mechanical response of transition zones linking two semi-infinite periodic structures, with the aim of making complex computations affordable and of reducing the computation time. The WFE method is applied on each periodic structure to write the response of the boundaries of the central zone in terms of left-going and right-going waves. Some amplitudes of these waves can be directly computed from the external load. To get the unknown wave amplitudes, the wave equations are combined with the dynamic equilibrium equation of the central zone. Thus, this method reduces the computation of the dynamics of a structure containing a transition zone linking two semi-infinite periodic zones to a wave problem at the boundaries of the transition zone coupled to a FEM modelling of the transition zone. In this paper, writing the problem only in terms of wave amplitude allows a much better conditioning of the linear system giving the solution to the problem compared to classical methods combining wave amplitudes and usual degrees of freedom at the mesh nodes. Special developments are made to account for moving loads on the whole infinite structure. The case of moving loads is particularly considered because of its applications to railways. For simple geometries, numerical studies show a strong agreement between results obtained with this method and other experimental and analytical results. More complex examples are given for railways tracks with damaged or reinforced zones. The calculation of stresses and damage criteria in components of the track for healthy, damaged and repaired railway tracks shows the interest in repair.]]></description>
      <pubDate>Fri, 30 May 2025 15:53:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2549199</guid>
    </item>
    <item>
      <title>Effect of strain waveform modeling and loading frequency on the fatigue life of asphalt concrete</title>
      <link>https://trid.trb.org/View/2493346</link>
      <description><![CDATA[The fatigue life of asphalt mixes in laboratory tests is commonly determined by applying a Sinusoidal or Haversine waveform with a specific frequency, while the pavement structure and loading conditions affect the shape and the frequency of tensile response pulses at the bottom of the asphalt layer. In this study, a Novel function is first evaluated to model the shape of the tensile strain waveform in longitudinal and transverse directions. The effect of strain waveform modeling using three waveforms of Haversine, Sinusoidal, and Novel on the fatigue life of asphalt mixes is then investigated through dynamic analysis of pavement and four-point bending beam fatigue test. All fatigue tests were continued to the third phase of fatigue life. Results showed a strong relationship between fatigue life based on the 50 % reduction of stiffness criteria and fatigue life based on energy methods under different loading waveforms and loading frequencies. It is also indicated that the loading waveform and frequency significantly affect the fatigue life of asphalt mixes. Much attention should be paid to determining these two parameters for a realistic simulation of the fatigue life of asphalt layers under the effect of moving loads. Furthermore, a new energy parameter is introduced to represent the fatigue life of asphalt mixes under a specific loading waveform at different loading frequencies. This energy parameter can be incorporated directly into pavement design.]]></description>
      <pubDate>Fri, 28 Feb 2025 16:46:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2493346</guid>
    </item>
    <item>
      <title>Analysis of Available In-Flight Measurements of Lightning Strikes to Aircraft</title>
      <link>https://trid.trb.org/View/1784720</link>
      <description><![CDATA[In the European FULMEN program, a collection together with an analysis of available data on lightning have been collected in a public database produced by Aerospatiale. This database contains data on In-flight and ground measurements, on In-flight incidents and manufacturer transfer functions. In this paper, the data of the in-flight measurements are presented. The In-flight data have been extracted from the Convair and Transall campaigns performed during summer 1985 and 1988 respectively. The measurements have shown that a lightning strike to an aircraft can be decomposed into four main phases: (1) the pre-breakdown phase associated with the general electrostatic condition just before the lightning, (2) the leaders development phase, (3) the recoil streamers phase and (4) the continuous current phase. For each phase, the main physical parameters (current, number of impulse current, impulse period, impulse duration, electric field, …) have been collected. Averages and cross correlation have been determined on these parameters. At the end of the analysis, the typical current waveform inferred from the measurements is shown and discussed.]]></description>
      <pubDate>Tue, 11 Feb 2025 15:52:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1784720</guid>
    </item>
    <item>
      <title>Study on Fatigue Strength of Welded Joints Subject to Intermittently Whipping Superimposed Wave Load</title>
      <link>https://trid.trb.org/View/1974296</link>
      <description><![CDATA[The stochastic characteristics of hull vibration superimposed stress waveform experienced by 6500 TEU container ship’s deck longitudinal is examined by Non-Linear Hydro-Elasticity Analyses. It is found that the stress waveform’s characteristics can be simplified so that the slamming impact occurs once in every 4 to 5 waves and the impact stress range is comparable to the wave stress range. Based on these results, the whipping superimposed stress waveform which are applied in fatigue tests are chosen. An electric exciter-driven plate bending vibration fatigue testing machine, which can apply various hull vibration superimposed stress waveform in high speed, is newly developed. Performing the whipping superimposed fatigue tests of welded joints using this machine, the validity of rainflow cycle counting for whipping superimposed loadings is examined. It is found that rainflow counting led to conservative estimates of fatigue lives, and the fatigue damage up to the failure of intermittently superimposed cases is larger than that of constantly superimposed cases under conditions chosen.]]></description>
      <pubDate>Fri, 23 Aug 2024 16:53:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1974296</guid>
    </item>
    <item>
      <title>Evaluate Geophysical Methods to Detect Underground Voids</title>
      <link>https://trid.trb.org/View/2401724</link>
      <description><![CDATA[Four geophysical methods were comparatively assessed for their ability to detect subsurface anomalies/voids, namely, Electrical Resistivity Tomography (ERT), Multichannel Analysis of Surface Waves (MASW), Ground Penetrating Radar (GPR), and Full-Waveform Inversion (FWI). The authors found that: a. ERT is well-suited for detecting and localizing subsurface anomalies, but may not be able to accurately size or characterize the material composition of an anomaly/void; b. MASW is unsuitable under most realistic field conditions; c. FWI appears suitable based on computational simulations, and would likely meet the demands of field conditions, but this capability was not tested; and d. GPR’s ability in anomaly detection is very limited due to depth constraints, it lacks consistency, and depends highly on operator experience; even when detection is successful, sizing and characterizing the anomaly using GPR is infeasible. Given field realities common to most infrastructure projects, the authors recommend the continued, but careful, use of ERT for detecting subsurface anomalies/voids. The authors also recommend that future research endeavors be concentrated on a. joint-inversion and multi-physics-based methods; b. software development.]]></description>
      <pubDate>Mon, 15 Jul 2024 09:05:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2401724</guid>
    </item>
    <item>
      <title>Construction of Prediction Model for Brain Strain Waveforms in Vehicle Crash Tests using Deep Learning</title>
      <link>https://trid.trb.org/View/2384478</link>
      <description><![CDATA[Brain strain indices calculated using human finite element models have recently been used to evaluate the brain injury risk in automobile accidents. However, the calculation using a finite element model of a human body is computationally expensive and time-consuming, making it impossible to evaluate brain strain indices immediately after a crash test. Therefore, this paper develops a deep learning model to predict the brain strain waveform from the angular velocity waveform of the head that can be measured by a crash dummy. The results of a comparison between the brain strain waveform obtained by finite element analysis and the waveform predicted by the developed deep learning model showed that the CORA evaluation exceeded 0.9, indicating that the model predicted the waveform with a high degree of accuracy.]]></description>
      <pubDate>Mon, 24 Jun 2024 09:26:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2384478</guid>
    </item>
    <item>
      <title>Ballast Fouling Measurement Tool – Phase II</title>
      <link>https://trid.trb.org/View/2387337</link>
      <description><![CDATA[Researchers developed a second-generation RAdar Ballast Inspection Tool (RABIT) using ground-penetrating radar (GPR) for use by track inspectors. This system is much lighter (26 lb/11.8 kg) than its predecessor (63 lb/29 kg) and is truly portable. It has a single bi-static antenna pair that straddles the tie so the ballast properties under the tie can be measured. During a measurement, the RABIT rolls down the track and obtains average ballast properties over a span of 10 cribs, thereby reducing problems associated with local variability in ballast properties and tie geometry. Researchers constructed a test track with known ballast properties and known fouling and moisture properties ranging from 0-30 percent and 0-4.5 percent by weight, respectively. A neural network was trained to map GPR waveforms to ballast fouling and moisture. The correlation factor between the RABIT estimates and measured values determined from physical ballast samples was better than 0.9. Researchers are planning further testing on in-service track to further validate the approach.]]></description>
      <pubDate>Sat, 08 Jun 2024 17:00:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2387337</guid>
    </item>
    <item>
      <title>Simulation and analysis of 5G waveforms to reduce BER for vehicular communications</title>
      <link>https://trid.trb.org/View/2371211</link>
      <description><![CDATA[In today's rapidly evolving world, wireless communication has become a pervasive force, profoundly impacting various facets of our daily lives. Wireless Vehicular Networks stand out as a captivating realm of research, with a key focus on fostering information exchange among autonomous vehicles. As researchers witness surging demand in this domain, there is a growing emphasis on devising advanced techniques to augment network performance, particularly within the context of Fifth-generation (5G) applications, such as vehicular communication. The concept of Vehicle-to-vehicle (V2V) communications is poised to play a pivotal role in the future, presenting formidable challenges for the air interface by accommodating asynchronous multiple access and high mobility. Within this dynamic landscape, security and privacy issues loom large for 5G-enabled vehicle networks, many of which remain largely unexplored. The conventional waveforms, including Orthogonal Frequency Division Multiplexing (OFDM), may fall short of meeting these evolving standards. In this paper, authors delve into a comparative exploration of two waveform families, namely Filter Bank Multicarrier (FBMC) and Universal Filtered Multi-Carrier (UFMC), concerning their design and performance trade-offs. authors also examine their compatibility with various digital modulation schemes like 4-Quadrature Amplitude Modulation (QAM), 16-QAM, Offset Quadrature Phase Shift Keying (OQPSK), and Shaped offset OQPSK (SOQPSK). Through MATLAB simulations, the authors' research vividly demonstrates the superior performance of UFMC when juxtaposed with OFDM and FBMC, especially concerning Bit Error Rate (BER) in both Rayleigh and Nakagami fading channels. In particular, authors consider a Nakagami shape parameter of 10, which yields a remarkable minimum BER for UFMC.]]></description>
      <pubDate>Tue, 30 Apr 2024 15:17:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2371211</guid>
    </item>
    <item>
      <title>Application of Traffic-Wave Theory in Air Traffic Flow</title>
      <link>https://trid.trb.org/View/2281523</link>
      <description><![CDATA[Air traffic flow converges from the route to the terminal area and then disperses to the airport. Research of the transmit mechanism has a significant importance on the efficiency control of queue length and congestion of the terminal area. In this process, the corresponding convergence wave and dissipation wave will come into being. In this paper, the basic principle of the traffic-wave is introduced. A traffic-wave equation suitable for air traffic flow is established, based on the Underwood speed-density model. In view of the particularity of air traffic flow, we will analyze the density of air traffic flow to research the propagation speed of the convergence wave and dissipation wave, and then we will obtain the mechanism of the queue length of the terminal area. To ensure the stability of the queue length, the relation of transmit time between the convergence wave and dissipation wave is also proposed. Finally, some examples will be used to validate the practicability and feasibility of the algorithms proposed above.]]></description>
      <pubDate>Fri, 23 Feb 2024 16:10:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2281523</guid>
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