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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Terahertz Band for High-Altitude Platform Station Communications: Performance Analysis, Potential, and Challenges</title>
      <link>https://trid.trb.org/View/2732068</link>
      <description><![CDATA[The Terahertz (THz) band (0.1–10 THz) attracts attention due to its massive bandwidth, potentially enabling ultra-high data rate with ultra-low latency. High-altitude platform stations (HAPSs) are envisioned as nodes of a non-terrestrial network (NTN) that complements terrestrial networks, particularly for connecting the unconnected and addressing temporary needs, such as disaster relief. THz HAPS communication is a promising solution for NTN, since HAPS is quasi-stationary in nature, located in the stratosphere, thereby avoiding beam misalignment and molecular absorption loss issues in the THz band. In this paper, we provide an overview of THz band HAPS communication, considering HAPS-to-ground, HAPS-to-HAPS, HAPS-to-satellite, and HAPS-to-uncrewed aerial vehicle links. We present simulation results of outage probability, ergodic capacity, and spectral efficiency under beam misalignment fading and turbulence fading in comparison to millimeter wave and sub-6 GHz bands. In addition, we summarize existing THz HAPS studies to reveal ongoing efforts. Moreover, we discuss open issues and research directions for THz band HAPS-related links. Overall, this paper draws a clear picture of THz HAPS communication by reporting its potential and challenges.]]></description>
      <pubDate>Wed, 12 Aug 2026 15:14:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732068</guid>
    </item>
    <item>
      <title>TCAS Compatibility Test Plan</title>
      <link>https://trid.trb.org/View/2717176</link>
      <description><![CDATA[The purpose of this test plan is to identify the data and methods of data collection, to determine the frequency guard bands needed to ensure mutual compatibility of the Traﬃc Alert and Collision Avoidance System (TCAS) and Tactical Air Navigation/Distance Measuring Equipment (TACAN/DME).]]></description>
      <pubDate>Sat, 11 Jul 2026 16:25:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2717176</guid>
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    <item>
      <title>Dual-Band Dual-Polarized Array Based on Electromagnetic Transparent Antenna for Vehicle-Mounted Base Station Systems</title>
      <link>https://trid.trb.org/View/2651930</link>
      <description><![CDATA[This paper introduces a novel ±45° shared-aperture, dual-band, dual-polarized interleaved array for vehicle-mounted base station systems. The array integrates a lower band (LB) antenna with four higher band (HB) antennas. To address the issue of cross-band scattering and its impact on higher band performance, we employ an innovative method that involves reducing the aperture size and incorporating lumped or distributed inductors. These inductors function as frequency-selective structures, permitting low-frequency currents to pass while blocking high-frequency currents. Consequently, at high frequencies, these inductors act as open circuits, making the low-frequency antenna radiator resemble multiple discontinuous small metal strips. This approach achieves an electromagnetic transparent (EMT) bandwidth of over 82.9%, making it highly suitable for mobile base station applications. By integrating this low-scattering LB antenna with four bandwidth-optimized cross dipoles, we achieve a dual-band interleaved array. The measured results confirm that the dual-band array operates effectively within the 0.85-0.98 GHz and 1.4-2.7 GHz frequency ranges, maintaining stable radiation performance. The superior performance of this design makes it an ideal choice for vehicle-based base stations.]]></description>
      <pubDate>Mon, 26 Jan 2026 08:41:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2651930</guid>
    </item>
    <item>
      <title>Cars and Trucks as Blockers and Reflectors in Vehicular ISAC Systems: Theory, Measurements, and Applications</title>
      <link>https://trid.trb.org/View/2601440</link>
      <description><![CDATA[Wireless propagation models form the basis for designing and evaluating both vehicular communications systems and vehicular wireless sensing systems as well as integrated sensing and communications (ISAC) systems. Of particular importance is the reflection from, and blockage by, moving objects such as other cars and trucks. This article discusses the ways in which the reflection and blockage characteristics can be measured, how to characterize them, and what values are typical in the different frequency ranges. We find that at high frequencies, reflections from vehicles tend to be more directional, while blockage by vehicles is more pronounced. All these characteristics influence applications in mono- and bistatic vehicular radars as well as the reliability of vehicular communications.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:07:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2601440</guid>
    </item>
    <item>
      <title>Isolated microgrid frequency stabilization through nonlinear model predictive control of a gas engine generator set</title>
      <link>https://trid.trb.org/View/2552337</link>
      <description><![CDATA[Gas engine generator sets are applied in microgrids due to their capability to provide reliable, responsive and efficient distributed power generation, enhancing grid resilience and enabling the integration of renewable energy sources. This article proposes a methodology for stabilizing the frequency of an isolated microgrid subjected to a measurable disturbance by controlling the power of a premixed turbocharged natural gas engine. Control difficulties of this task include strongly nonlinear dynamics, time delay in the air-fuel path and constrained operating conditions. Conventional control methods like proportional-integral control have difficulties solving these problems, and require extensive tuning efforts and gain scheduling to deliver acceptable performance, prompting adoption of advanced control strategies. The presented approach utilizes a cascaded control architecture with a nonlinear model predictive controller (NMPC) for high level control and engine specific low-level controllers for controlling the intake manifold pressure and air-fuel ratio. The NMPC captures the inherent nonlinear dynamics, accounts for an input delay and handles state-dependent constraints. The cascaded control architecture enables the usage of a comparably simple model for the NMPC design, reducing the computational cost and the parametrization effort. This additionally enables application of the high level controller for different gas engine types and allows design of the controller in a simple simulation environment prior to the experiments on the real engine. Experimental results highlight the NMPC’s ability to control the engine at its physical limits over the entire load range without inducing frequency oscillations using just one parameter set. This emphasizes the robustness of the presented approach, making it a promising solution for real-world applications.]]></description>
      <pubDate>Tue, 17 Jun 2025 09:58:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2552337</guid>
    </item>
    <item>
      <title>Millimeter-Wave Channel Modeling and Coverage Analysis for Indoor Dense Spaces</title>
      <link>https://trid.trb.org/View/2543236</link>
      <description><![CDATA[Millimeter-wave channel modeling for airplanes, trains, and other in-vehicle environments can be considered jointly as different variations of a general site, namely an indoor dense space (IDS). In this work, by using ray-tracing (RT) simulations, the authors compare the effect of frame material, user density, and geometry on the channel characteristics at 28, 39, and 60 GHz bands. The authors observe that temporal and spatial parameters in IDS have unique distributions some depending on the transmitter (TX)-receiver (RX) separation in comparison to the indoor office (IO) channel model. The frame material is the main determining factor of the channel characteristics, while variations in frequency bands and geometries have only a minor impact. The authors extend our channel modeling effort to MIMO deployment analysis to compare the validity of the proposed model in terms of coverage and spectral efficiency with the IO model. Several dominant angular intervals in the channel cause five times higher spectral efficiency gained by digital beamforming (BF) in comparison to analog BF. The authors observe that the path loss in IDS is more severe compared with IO, resulting in at least a 50% reduction in the coverage area.]]></description>
      <pubDate>Tue, 27 May 2025 09:33:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2543236</guid>
    </item>
    <item>
      <title>Joint Carrier Frequency Offset, Doubly Selective Channel Estimation and Data Detection for RIS Assisted MIMO OFDMA Uplink System</title>
      <link>https://trid.trb.org/View/2537210</link>
      <description><![CDATA[With the presence of an array of passive elements embedded in a reconfigurable intelligent surface (RIS), estimation of time-varying channels between a fast-moving user and the fixed base station (BS) is more challenging than conventional static channels. In this paper, the authors propose a joint technique for the estimation of carrier frequency offset (CFO) and doubly selective channel (DSC), and data detection in the RIS-assisted multiple input multiple output (MIMO) orthogonal frequency division multiple access (OFDMA) uplink system. The time variations of the channel within the OFDMA symbol are represented using the basis expansion model (BEM), significantly reducing the number of estimated parameters. An autoregressive (AR) model is used to characterize the variations in BEM coefficients and CFOs over successive OFDMA symbols. A novel technique of combining the Schmidt extended Kalman filtering (SEKF) and Gaussian particle filtering (GPF) integrated with an iterative detector and decoder (IDD) receiver structure (IDD-SKGPF) is proposed to estimate the BEM coefficients, CFOs and to detect the symbols in two stages. Performance of the proposed method is evaluated using normalized mean square error (NMSE) and compared with the derived Bayesian Cramer-Rao bound (BCRB) and modified BCRB. Furthermore, the reflection coefficient is optimized in the time domain by maximizing the achievable rate to demonstrate that the exploitation of RIS may result in significant bit error rate (BER) performance improvement of 6dB in SNR over non optimized RIS scenario even under high mobility scenarios.]]></description>
      <pubDate>Tue, 29 Apr 2025 09:23:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2537210</guid>
    </item>
    <item>
      <title>Short Binary Sequence-Based Fast Electrochemical Impedance Spectroscopy Measurement for Lithium-Ion Batteries</title>
      <link>https://trid.trb.org/View/2511490</link>
      <description><![CDATA[Wideband signals effectively shorten the measurement time for acquiring electrochemical impedance spectroscopy (EIS) of lithium-ion batteries (LIBs). However, the measurement accuracy and measurable frequency range are limited due to an insufficient signal-to-noise ratio (SNR). Given this issue, this article proposes a short binary sequence-based fast EIS measurement approach. First, a short inverse repeat binary sequence (SIRBS) is specially designed to enhance the SNR, especially in the low-frequency region. Then, a wideband impedance extraction algorithm based on the Airy wavelet transform is proposed to address the high-frequency measurement distortion and frequency resolution decrease caused by the SIRBS. Finally, the effectiveness of the proposed approach is verified on an EIS measurement system based on a bidirectional buck-boost converter. Under a response voltage amplitude of less than 10 mV, the proposed measurement approach requires only one disturbance period (10 s) to obtain the EIS in the frequency range of 0.1 Hz–2 kHz. The experimental results indicate that under different state-of-charge (SOC), temperatures, and aging states, the maximum normalized root mean square error (RMSE) and the normalized maximum absolute error (NMAE) are mainly maintained below 0.38% and 0.97%, respectively. Moreover, the superiority of the proposed approach is further demonstrated by comparative analyses with existing techniques.]]></description>
      <pubDate>Tue, 22 Apr 2025 15:51:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2511490</guid>
    </item>
    <item>
      <title>Identification of multiple bridge frequencies using a movable test vehicle by approximating axle responses to contact-point responses: theory and experiment</title>
      <link>https://trid.trb.org/View/2529988</link>
      <description><![CDATA[Identifying bridge frequencies using a movable test vehicle is highly regarded for its mobility, cost-effectiveness, and broad monitoring coverage. Although experiments have shown effectiveness in extracting the fundamental bridge frequency, there are certain challenges in identifying higher-order frequencies, primarily owing to the impact of road surface roughness and vehicle self-vibrations. Theoretical studies have proposed mitigation strategies such as using contact-point (CP) responses and time-lagged signal subtraction. However, generating accurate CP responses in real-world measurements remains challenging owing to uncertainties in vehicle parameter measurements and susceptibility to environmental noise. This study proposed a novel vehicle scanning approach that approximates the axle response to the CP response. Initially, closed-form solutions for the axle-to-CP response deviations of a quarter-car vehicle traversing a simple beam were derived, considering scenarios with and without surface roughness. Subsequently, parametric studies were performed to analyze the condition of the test vehicle design for approximating the axle responses to the CP responses. Consequently, finite element simulations of the vehicle-bridge interaction system were established to validate the theoretical derivations. Finally, the theoretical findings were used to design a scaled test vehicle, and laboratory tests of a scaled vehicle-bridge interaction system verified the proposed approach. The theoretical and experimental findings suggest that, by designing a test vehicle with a sufficiently large axle stiffness, the axle responses can be approximated as CP responses. As a result, the measurement of the axle accelerations on a test vehicle facilitated the identification of multiple bridge frequencies.]]></description>
      <pubDate>Tue, 22 Apr 2025 13:17:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2529988</guid>
    </item>
    <item>
      <title>Adaptive DMPC-Based Frequency and Voltage Control for Microgrid Deploying a Novel EV-Based Virtual Energy Router</title>
      <link>https://trid.trb.org/View/2511734</link>
      <description><![CDATA[The widespread use of electric vehicles (EVs) has introduced many mobile energy storage devices to the power grid. Originally, this article first proposes a novel concept of an EV-based virtual energy router (VER). Through utilizing the energy storage and mobility capabilities of EVs, EV-based VERs can dynamically share power supply within microgrids by adaptive frequency and voltage regulation. Based on the grid-forming role of EV-based VERs, an adaptive distributed model predictive control (DMPC) is proposed for frequency and voltage regulation. First, a discrete predictive model is built based on the primary control with virtual inertia. Adaptable parameters are adopted to accommodate the variable capacity of EV-based VERs. Second, a centralized MPC scheme is designed to achieve accurate dynamic power sharing, frequency restoration, and voltage restoration. Third, the DMPC framework is proposed to decompose the centralized MPC by the designed correction multipliers, which can relax dynamic power sharing constraints. Finally, the authors analyze the convergence of the distributed algorithm and the stability of the dual-rate sampling system, formed by the adaptive primary control and DMPC-based secondary control. The simulations and experiments verify the effectiveness of the proposed control.]]></description>
      <pubDate>Wed, 16 Apr 2025 11:24:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2511734</guid>
    </item>
    <item>
      <title>Study of sound patterns and sound perception in electrified trucks</title>
      <link>https://trid.trb.org/View/2534226</link>
      <description><![CDATA[During the process of development of electric heavy vehicles the focus on sound quality have become much more important. Shifting the internal combustion engine to electric propulsion, has not only decreased the sound levels. The sonic character is now more tonal and needs other evaluation routines and new target settings. The purpose of this work is to define applicable methods and target values to, in the long term, secure good sound quality and safe vehicles. To accomplish this mission several sub-questions needs to be investigated such as perception of prominence and loudness of complex tones, underlying aspects for evaluation of sounds as well as behavioural effects and comfort during driving. In the present work, listening tests were made to study how the number of tone components and frequency intervals between the components affect the perception of the perceived loudness of complex tones. The listening tests revealed that there is a linear relationship between perceived loudness and increasing number of harmonics of a complex tone with amplitudes of the partials decreasing 6 dB per octave. To study underlying aspects for sound assessments, qualitative data from a previously performed listening test on a first-generation battery electric truck was studied. The method of thematic analysis was used to derive information about what decided if a sound was evaluated as positive or negative. Various aspects have an impact on the outcome. Interrelation between tonal components needs to be considered when setting targets on sounds with complex tonal content to give valid estimations of loudness and prominence. Subjective evaluation of dynamic driving operations depends of several different factors. These are connected to the individual such as listening and contextual experience, individual values and preferences, hearing function, relation between feedback and input as well as acoustical features. Informative sounds with close connection to load and speed are desirable.]]></description>
      <pubDate>Fri, 04 Apr 2025 15:15:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2534226</guid>
    </item>
    <item>
      <title>Models of Spatial and Planar Light Bar Structures in the Maple System</title>
      <link>https://trid.trb.org/View/2407809</link>
      <description><![CDATA[Models of planar and spatial statically determinate regular trusses and analytical solutions of the problem of calculating natural frequencies are considered. A beam planar truss with triangular lattice, planar and spatial cantilever trusses are considered. To calculate the forces in the elements of the structure and calculate the rigidity of the structure in an analytical form, the computer mathematics system Maple was used. The dependence of the solutions on the number of panels was found by the induction method. To do this, the authors looked for common members of the sequences of coefficients included in solutions for trusses with a sequentially increasing number of panels. An algorithm for calculating the estimate of the first frequency by Dunkerley is given. In the spectra of eigenfrequencies of regular structures, frequencies are found that are the same for structures of any order (spectral constants) and frequencies with the same number in ordered spectra, forming curves in the axes “frequency number in the spectrum - order of construction” curves tending to spectral constants.]]></description>
      <pubDate>Fri, 21 Mar 2025 09:14:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407809</guid>
    </item>
    <item>
      <title>Compact 5 G mmWave vivaldi antenna for vehicular communication</title>
      <link>https://trid.trb.org/View/2506391</link>
      <description><![CDATA[As a key contribution, this article presents the first successful application of the newly developed Vivaldi Non-uniform Profile Antenna (VNSPA) theory to a Vivaldi Tapered Slot Antenna (VTSA) operating in the 26 GHz band (24.25–27.5 GHz). The proposed design achieves both compactness and simplicity while maintaining high performance. This antenna is a promising candidate for vehicular communication applications, aiming to enhance connectivity, road safety, security, and environmental system control. First, a VTSA with a small volume of 8.1 × 8.3 × 0.813 mm³ is designed, fabricated, and tested, providing S₁₁ value < -11.34 dB at 15.96–28.41 GHz and a maximum realized gain of 6 dBi. Second, a 33 % size reduction of its tapered slot profile (TSP) is obtained by applying the VNSPA theory, resulting in the Vivaldi Non-uniform Slot Antenna (VNSA). Based on this theory, two different non-uniform slot profiles (NSPs) are obtained for VNSA 1 and 2 with final 37 % and 32.55 % volume reduction, respectively, based on parametric studies. VNSA 1 and 2 provide S₁₁ values < -11.6 dB and < -14.3 dB at 16.71 to 27.68 GHz and 17.94 to 27.38 GHz with peak realized gains of 4.6 dBi and 5.15 dBi, respectively. Another key contribution of this research is the on-vehicle analysis of the proposed antenna's applicability for communication. This includes testing the antenna in various positions and demonstrating its capability to radiate in multiple directions, enabling effective communication with other vehicles, pedestrians, roadside units, and mobile networks. Another significant aspect of this research is the calculation of specific absorption rate (SAR), which addresses the effects of electromagnetic radiation on the driver, one back-seat passenger, and pedestrians. The Computer Simulation Technology (CST) software is used to carry out the simulation.]]></description>
      <pubDate>Fri, 07 Mar 2025 15:07:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2506391</guid>
    </item>
    <item>
      <title>Study and Characterization of Gaskets in the Frequency Band [100 kHz - 100 MHz]</title>
      <link>https://trid.trb.org/View/1784757</link>
      <description><![CDATA[The aim of the present work is to find a pertinent parameter characterizing gaskets, such as used in joints in metallic enclosures, over the [100kHz - 100MHz] frequency band. The proposed test device provides a frequency measure of the coupling, between two wires placed on both sides of the assembly. The authors can then define an equivalent generator on the reception line. Then, starting from Latham’s analysis [1], the authors have obtained a pertinent parameter considered as a transfer impedance. This transfer impedance behaves, at low frequencies, like a surface impedance and thus can be taken into account in numerical codes, as, for example, codes based on the EFIE. The authors have modeled their experimental device and they have used the above technique to characterize an elastomer gasket in an overlap-type joint. The value of the coupling function is obtained numerically using a reciprocity technique because the direct calculation is not precise enough (signal of the order of magnitude of the numerical noise). The authors have compared the numerical results with those obtained from measurements, and they have obtained a good agreement between them. The authors will analyze the different physical mechanisms and discuss the domain of validity of this technique.]]></description>
      <pubDate>Mon, 24 Feb 2025 09:11:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1784757</guid>
    </item>
    <item>
      <title>Incentivizing EVs to Provide Frequency Regulation Services by Aggregative Game-Based Mechanism</title>
      <link>https://trid.trb.org/View/2458904</link>
      <description><![CDATA[The proliferation of electric vehicles (EVs) provides a promising resource for regulation services to maintain the frequency of power systems. However, two major problems hinder its implementation, including the inaccuracy of the EV charging model and the overlook of varieties in EV ownership. To facilitate real-world implementation, this paper tailors a market-based mechanism to incentivize EVs to provide frequency regulation services. Firstly, a detailed EV charging model considering the battery equivalent circuit and AC-DC conversion loss is proposed. The nonconvexities are approximated and convexified with accuracy guarantee. Then, based on the self-interest behavior of EVs, a non-cooperative game is adopted to model the competition in providing frequency regulation service. The aggregative game is used to approximate the original non-cooperative game. Thereby, the existence, uniqueness, and approximation accuracy of the aggregative equilibrium is theoretically proved. Moreover, the rolling look-ahead iterative frequency regulation service clearing mechanism for EV parking lot is designed based on the decentralized equilibrium searching algorithm of the aggregative game. Finally, the effectiveness, computational efficiency, and approximation accuracy of the proposed market-based mechanism are validated by a series of numerical tests with EV populations at 50, 100, 200, 300, 600, and 900.]]></description>
      <pubDate>Fri, 22 Nov 2024 14:31:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2458904</guid>
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