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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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Airframe scattering of engine fan noise</title>
      <link>https://trid.trb.org/View/2700548</link>
      <description><![CDATA[This paper presents a study on aircraft engine fan noise scattering by the airframe structure, using a methodology in the framework of geometric acoustics with extensions to account for features that are important for aircraft noise but are absent in classic geometric acoustics. Methods to parameterize engine fan noise sources for scattering calculation are presented and the important feature of source coherence is discussed, with examples given to demonstrate its effects in experimental data and in computation. The scattering results calculated for the Boeing 787 aircraft are presented and analyzed, for both the inlet and the aft fan component, and for both the broadband and the tonal noise. Many features are shown to be consistent with, and/or provide explanations for, observations in flight test data. The methodology and capabilities described in this study are written into the NASA PAASc code and represent a necessary and significant improvement in the accuracy and capabilities for acoustic scattering prediction while meeting the rigorous requirements of aircraft system noise assessments and design studies.]]></description>
      <pubDate>Wed, 20 May 2026 09:10:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2700548</guid>
    </item>
    <item>
      <title>Artificial Intelligence-Enhanced Scattering Modeling for Intelligent Transportation Systems: A New Approach</title>
      <link>https://trid.trb.org/View/2601439</link>
      <description><![CDATA[With the rapid development of the 6G technology, intelligent transportation systems (ITS) will be instrumental in achieving efficient traffic management and ensuring safety. The accurate electromagnetic (EM) characterization of scatterers will play a crucial role for improving their integrated sensing and communication (ISAC) capabilities. Toward this goal, this article considers the application of artificial intelligence (AI) techniques for enhancing the scattering modeling for ITS applications. First, a comprehensive review of existing methods for scattering modeling is presented. By identifying their strengths and limitations, potential enhancements brought by AI-based methods are discussed. Second, by considering typical scatterers in ITS—namely pedestrians, vehicles, and vegetation—the EM modeling methods to meet their diverse requirements are identified and categorized. Next the challenges in achieving cross-frequency consistency in EM characteristic representation, accurate modeling of complex multipath effects, and balancing real-time performance versus computational efficiency are identified. Future research trends and directions, which can be used in connection with AI-enhanced methods, are also discussed. Finally, a new approach for incorporating AI-enhanced methods to jointly model typical scatterers encountered in ITS is introduced. It is argued that the use of AI can lead to more accurate and computational efficient scattering modeling for ITS applications.]]></description>
      <pubDate>Mon, 22 Dec 2025 16:07:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2601439</guid>
    </item>
    <item>
      <title>Experimental study of laser scattering protection system for low-speed aircraft</title>
      <link>https://trid.trb.org/View/2422937</link>
      <description><![CDATA[This study introduces a laser scattering system to protect a low-speed aircraft. Scattering was selected to reduce the laser's intensity targeting the sensor of an aircraft and simultaneously maintaining the functionality of aircraft optics. Mie scattering, known for effectively decreasing short-wave infrared light, was employed by utilizing water aerosols having a diameter of 1 to 5 mum. Experimental results regarding the decrease of the laser intensity via scattering confirmed that the theoretical and experimental values resulted in a similar decrease rate under static conditions. To validate the theoretical values, the path length, which the laser passing through water aerosols, was changed. To assess the system's feasibility in flow conditions, a low-speed wind tunnel was employed to generate two flow speeds: 5.5 m/s and 17.6 m/s. Remarkably, the reduction of laser intensity was only affected by the path length, and was somewhat unaffected regardless of flow speed and the uniformity of the flow, only to the path length. In all cases, the initial laser intensity was set to 10 mW. Under static conditions, the intensity dropped to 8.21 mW, showing a decrease of 17.9%. In flow conditions of 5.5 m/s, 17.6 m/s, and in distorted flow, the laser intensity decreased by 18.3%, 18.1%, and 18% respectively. As a preliminary study, these results demonstrate the system's capability to protect a low-speed aircraft targeted by lasers even under dynamic flow conditions, may suggest a possibility of providing a practical defence solution. Copyright: © 2024 Kim, Park. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.]]></description>
      <pubDate>Tue, 22 Apr 2025 15:51:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2422937</guid>
    </item>
    <item>
      <title>EPQ-GAN: Evolutionary Perceptual Quality Assessment Generative Adversarial Network for Image Dehazing</title>
      <link>https://trid.trb.org/View/2441974</link>
      <description><![CDATA[Single image dehazing is a challenging issue with the goal to improve the quality of hazy images for computer vision applications and surveillance systems. The majority of current techniques aim to restore clear images from hazy images by approximating the transmission map and global atmospheric light. However, inaccurate estimation of these factors results in unrealistic outcomes. To overcome these challenges and to produce realistic images, the authors implemented a new approach called the Evolutionary Perceptual Quality Assessment Generative Adversarial Network (EPQ-GAN). The EPQ-GAN comprises a novel Evolutionary Generator and Discriminator. The Evolutionary training of the Generator can improve generative performance; hence, to train the Evolutionary Generator, the proposed method adopted the Differential evolution (DE) algorithm and the entire GAN network is trained with Perceptual loss from the discriminator, quality assessment loss (PSNR Loss) and adversarial loss. The proposed EPQ-GAN has superior performance compared to other state-of-the-art approaches, as evidenced by both qualitative and quantitative examination of several benchmark datasets.]]></description>
      <pubDate>Mon, 13 Jan 2025 11:12:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2441974</guid>
    </item>
    <item>
      <title>Heading Measurement Frame Based on Atmospheric Scattering Beams for Intelligent Vehicle</title>
      <link>https://trid.trb.org/View/2441990</link>
      <description><![CDATA[Autonomous orientation technology has major engineering significance for intelligent transportation systems (ITS) especially for the intelligent vehicle. The sky polarization characteristics offer a wealth of navigation data. At present, the most advanced polarization navigators can output this navigation information and do not require complex optical structures. However, these current navigation methods are limited severely by the sky conditions, and it is difficult to achieve orientation accurately under interference from reflected light. Here, the authors report a sky recognition algorithm based on a region prior approach to reduce the influence of the reflected light. Furthermore, to solve the sun fuzzy problem, a morphometric template matching in transform domain (MTMTD) strategy is proposed based on the angle of polarization (AOP). The application scope an fd practicability of the method are improved effectively by using all the effective pixels as a navigation unit. In addition, this method turns these pixels into curves, which means that even when only one pixel is observed, the sun fuzzy problem can be solved exactly. Their results efficiently verify the feasibility of the proposed strategy, which may provide an interesting solution for heading measurement of intelligent vehicle.]]></description>
      <pubDate>Mon, 13 Jan 2025 09:14:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2441990</guid>
    </item>
    <item>
      <title>Investigating the WSSUS Assumption in 300 GHz Time-Variant Channels in Industrial Environments</title>
      <link>https://trid.trb.org/View/2448735</link>
      <description><![CDATA[This paper present an initial approach to the analysis of the stationarity of time-variant channels in industrial environments, focusing on three distinct scenarios: 1) communication between a static access point (AP) and a sensor node (SN) mounted on a moving machine within a comprehensive industrial workspace, 2) communication between two static sensor node (SN) with a moving metal plate object between them, and 3) communication between two static robotic manipulators with a moving obstacle with varying movement speeds between them. The assumptions of the wide-sense stationary (WSS) and uncorrelated scattering (US), fundamental to channel modeling, are examined using local scattering function (LSF) collinearity metrics in both time and frequency domains. In blockage scenarios, where the authors compared the effects of two different types of obstacles – a metal plate and a robotic arm – the channel behavior can be divided into three distinct regions: fully stationary before and after the blockage, non-stationary during the transition periods, and either conditionally stationary or fully non-stationary during partial or full blockage, respectively. These distinctions were influenced by the type of blockage object and whether the scenario involved non-line-of-sight (NLOS) or obstructed-line-of-sight (OLOS) conditions. Notably, the speed of moving obstacles affects the duration and nature of non-stationary regions, with higher speeds leading to shorter and less distinct transition periods. The US assumption was found to be generally valid in the blockage scenarios but not in the AP scenario.]]></description>
      <pubDate>Fri, 22 Nov 2024 14:59:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2448735</guid>
    </item>
    <item>
      <title>Advanced concrete pavement internal crack monitoring using wave response variation and deep learning</title>
      <link>https://trid.trb.org/View/2435146</link>
      <description><![CDATA[This paper presents an in-depth investigation into internal crack monitoring in concrete pavement through the application of wave response variation (WRV) and deep learning techniques. The study examines wave scattering in both homogeneous (HM) and inhomogeneous (IHM) media, validating WRV by analyzing forward scattering due to interval vertical cracks through laboratory tests and analytical solutions. It compares various laboratory tests with experimental and finite element (FE) results. The analysis reveals that shallower cracks result in peaks at lower impulse frequencies on the WRV curve, while deeper cracks correspond to peaks at higher frequencies, as observed from both forward and incident waves. The study also finds that the complexity of IHM, influenced by random aggregate size and distribution, significantly affects WRV patterns, with larger aggregates causing greater energy attenuation in forward waves compared to smaller aggregates. Machine learning (ML) techniques are employed to predict cracks and clarify the impact of aggregate information on WRV. This research establishes a framework for understanding internal damage in IHM using ML technology. This study enables effective monitoring of internal vertical cracks, such as reflective cracks in bridge decks, pavements, and airport runways.]]></description>
      <pubDate>Fri, 18 Oct 2024 14:08:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2435146</guid>
    </item>
    <item>
      <title>Tracking of Rectangular Object Using Key Points With Regionally Concentrated Measurements</title>
      <link>https://trid.trb.org/View/2389677</link>
      <description><![CDATA[Extended object tracking (EOT) has attracted much attention in recent years. EOT approaches always assume that scattering centers are distributed on the boundary of or uniformly over the object extension. However, a practical distribution is complex and scattering centers can be concentrated on regions of the extension. To describe this phenomenon, a key-point-based model is proposed. It partitions a rectangular object extension into four regions that intersect at a key point. Over different regions scattering centers are assumed uniformly distributed with different densities related to the area of the regions. Thus, the overall complex distribution of regionally concentrated measurements can be described by combining the four local simple ones. The variation of the key point’s position on the object can affect the four regions in size and shape, and thus can characterize different overall distributions. Estimation of the extension amounts to that of the key point’s kinematic state, the object orientation, and the length and width of each region. Based on the proposed model, measurements are projected into two directions along with and perpendicular to the object orientation approximated by its prediction, respectively. Variances of the projected measurements in the two directions are derived to be Gamma distributed. Using the conjugate property of a Gamma and an inverse Gamma distributions, an analytical recursive estimator of the kinematic state and the length and width variables is obtained. The effectiveness of the proposed approach is illustrated using both simulated and real data.]]></description>
      <pubDate>Tue, 01 Oct 2024 09:48:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389677</guid>
    </item>
    <item>
      <title>Hydrostatic stability of steel-slag porous asphalt mixture based on freeze-thaw cycle testing</title>
      <link>https://trid.trb.org/View/2425715</link>
      <description><![CDATA[This study was conducted to investigate the hydrostatic stability of a steel slag porous asphalt mixture (SSPA) under freeze-thaw cycles in seasonal frozen soil areas and thereafter, compare its (SSPA) characteristic properties and advantages with a traditional porous asphalt pavement. In the study, the freeze-thaw stability of SSPA was tested through multiple freeze-thaw cycle splitting, scattering loss, and trabecular bending tests under various cyclic temperature water immersion conditions including quantitatively analyzing the SSPA volumetric changes. In addition, the scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) tests were used to analyze the microscopic damage mechanism of SSPA after being subjected to various cyclic temperature water immersion conditions. The corresponding test results indicated that: (a) the long-term freeze-thaw cycles had significant adverse effects on the hydrostatic stability, physical/mechanical properties, and volume stability of SSPA; and (b) when the melting temperature was increased, both the hydrostatic stability and mass gain/loss ratio of SSPA decreased whilst the void ratio increased. On the other hand, the SEM and EDS results showed that an increase in the number of freeze-thaw cycles or melting temperature led to a corresponding increase in the width of the steel slag-asphalt transition zone. This resulted in a weakening of the mechanical connection and anchorage between steel slag and asphalt, as well as the destruction of their adhesion bond. However, the short-term freeze-thaw cycles had little effect on the hydrostatic stability of SSPA because the steel slag-asphalt interfacial strength was enhanced by short-term freeze-thaw cycles.]]></description>
      <pubDate>Fri, 13 Sep 2024 10:35:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2425715</guid>
    </item>
    <item>
      <title>Visible Light Communication-Enabled Simultaneous Position and Orientation Detection for Harnessing Multipath Interference and Random Fading</title>
      <link>https://trid.trb.org/View/2337209</link>
      <description><![CDATA[The authors focus on visible light communication-based simultaneous position and orientation detection (SPAO) for user devices (UDs) using photodiodes, which is challenging due to scattering interference and small-scale fading. To address this challenge, a novel SPAO approach is proposed, which can jointly estimate UD location parameters and scattering channel states. As such, the disturbance of diffuse scattering and random fading on SPAO will be alleviated via scattering channel equalization. In addition, SPAO is non-convex in nature, and hence brute-force application of conventional optimization methods will lead to a poor SPAO solution. To address this issue, they devise a majorization minimization (MM)-based SPAO algorithm, where hidden convex structure of the non-convex SPAO problem is exploited, which renders an efficient closed-form iteration rule for joint SPAO and diffuse channel estimation. Due to the cross-layer cooperation between “VLC” and “ranging”, a robust SPAO solution against diffuse scattering and small-scale fading is achieved. It is corroborated by their simulations that the proposed MM-based SPAO algorithm achieves a large performance gain over state-of-the-art baseline methods.]]></description>
      <pubDate>Wed, 03 Jul 2024 09:04:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2337209</guid>
    </item>
    <item>
      <title>6G Integrated Sensing and Communications Channel Modeling: Challenges and Opportunities</title>
      <link>https://trid.trb.org/View/2389260</link>
      <description><![CDATA[The advent of 6G communication systems has enabled, through integrated sensing and communications (ISAC), the vision of the intelligent connection of everything. Since such ISAC systems will be utilizing the sub-6-GHz and millimeter-wave (mm-wave) bands, appropriate hybrid, i.e., sensing and communication channel models, are required for their proper operation. This article first presents a comprehensive survey of channel models used in ISAC applications viewed from different modeling perspectives by identifying the challenges encountered in these modeling approaches. A novel hybrid approach for ISAC channel modeling is then introduced wherein the modeling methodology is partitioned into three elements: targets, clutters, and interferences. The advantage of such a flexible modeling approach using these three elements enhances the proposed model’s ability to effectively deal with the specific sensing and communication operational requirements. Finally, further performance enhancement methods, based upon real-time 3D environment reconstruction techniques as well as artificial intelligence (AI), are proposed and discussed.]]></description>
      <pubDate>Thu, 27 Jun 2024 14:03:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389260</guid>
    </item>
    <item>
      <title>Integrated Sensing and Communication Channel Modeling and Measurements: Requirements and Methodologies Toward 6G Standardization</title>
      <link>https://trid.trb.org/View/2389259</link>
      <description><![CDATA[Integrated sensing and communication (ISAC) has been defined as one of the major usage scenarios for 6G. When sensing and communication channels coexist in ISAC scenarios, neither conventional communication nor sensing channel models are applicable. As the foundation of ISAC studies, a new channel modeling methodology is required to characterize both sensing and communication channels and their correlations. This article introduces the framework of a general ISAC channel model, which integrates a deterministic multiscattering-center (MSC) model of sensing targets to the stochastic propagation channel model. Parameterizations of the proposed channel model rely on channel measurements. This article introduces two ISAC channel measurement methodologies based on the vector network analyzer (VNA) and a novel dual-sensor measurement system. The proposed methods can be applied in future 6G ISAC channel model standardization and system evaluations.]]></description>
      <pubDate>Thu, 27 Jun 2024 14:03:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389259</guid>
    </item>
    <item>
      <title>2D Diesel Spray Droplet Size Mapping Based on Planar Laser Induced Fluorescence and Mie-Scattering Technique Using Sparsity Deconvolution</title>
      <link>https://trid.trb.org/View/2367383</link>
      <description><![CDATA[The distribution of spray droplet sizes plays a pivotal role in internal combustion engines, directly affecting fuel-air mixing, evaporation, and combustion. To gain a precise understanding of droplet size distribution in a two-dimensional space, non-intrusive optical diagnostics emerge as a highly effective method. In the current investigation, two-dimensional (2D) diesel spray droplet sizes mapping using a simultaneous combination of planar laser-induced fluorescence (PLIF) and Mie-scattering techniques is introduced. The assessment of droplet diameter relies on the interplay between fluorescent and scattered light intensities which correspond the light based on volumetric droplets and surface area of the droplets. This calculation is made possible through the LIF/Mie technique. However, traditional LIF/Mie methods are plagued by inaccuracies arising from multiple light scattering. To overcome this challenge and to attain higher accuracy than conventional LIF/Mie technique, the authors introduce a sparsity deconvolution approach to eliminate unwanted light interference on both LIF and Mie images. The core concept of sparsity deconvolution is to reduce disturbances caused by multiple scattering and offer sharp and finely detailed images for LIF/Mie ratio estimation. To enhance spatial sharpness and remove the undesired scattering light, an iterative Richardson–Lucy (RL) and Land Weber (LW) filters are introduced for image deconvolution. The results reveal that RL deconvolution is particularly well-suited for the intricate task of deconvolving complex liquid sprays, producing sharper and finer detailed droplet images. Additionally, the further calibration of 2D droplet size mapping based on microscopic method is implemented to approximate the linear fitting curve of dependence between macro LIF/Mie ratio and droplet diameter. This comprehensive approach advances the understanding of the critical role played by droplet size distribution under engine-like conditions.]]></description>
      <pubDate>Sun, 05 May 2024 17:28:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2367383</guid>
    </item>
    <item>
      <title>Investigations on electromagnetic scattering characteristics of aircraft rudder considering electromagnetic discontinuities</title>
      <link>https://trid.trb.org/View/2296356</link>
      <description><![CDATA[This work investigates the scattering characteristics of the rudder structure of aircraft considering electromagnetic discontinuities through multi level fast multipole algorithm (MLFMA) of the computational electromagnetics. Firstly, the scattering characteristics of the rudder seam and its influence on the omnidirectional radar cross section (RCS) are performed. Based on the traditional high-frequency analysis theory, the source and spatial contribution distribution of seam scattering are further studied. Numerical results demonstrate that the sidewall of the rudder seam is an important scattering source, and the radar absorbing material (RAM) coated on the sidewall of the seam has a good RCS reduction effect. In addition, this work presents the influence of the rudder deflection on the stealth performance, analyzes the effect of the rudder movement of the ordinary aileron and the split drag rudder on the scattering characteristics of the whole aircraft. The common aileron has little effect on the stealth performance of the aircraft, and it only causes scattering peak in the direction opposite to the control surface. However, the split drag rudder has great damage to the opposite direction stealth performance of the aircraft. When its deflection angle is 45°, the mean value of the opposite direction RCS increases by about two orders of magnitude compared with the deflection angle 0° state. The results indicate that the structure of aircraft rudder has a significant impact on the RCS characteristics of the whole aircraft.]]></description>
      <pubDate>Thu, 28 Dec 2023 13:28:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2296356</guid>
    </item>
    <item>
      <title>Quantifying extinction imaging of fuel sprays considering scattering errors</title>
      <link>https://trid.trb.org/View/2287605</link>
      <description><![CDATA[In this work, the authors use the measurement technique of high-speed Diffuse Back Illumination Extinction Imaging (DBI-EI) to obtain quantitative information in the form of projected liquid volume (PLV) in a highly transient GDI process. For the DBI-EI setup they use a LED-Panel as the light source, which fulfills diffuse back illumination extinction imaging criteria. Measurements were carried out in a constant volume chamber, allowing easy optical access, and enabling measurements at real world ambient engine conditions. For the experiments, the authors use an Engine Combustion Network (ECN) Spray G injector and measure the sprays at ECN conditions. Moreover, they mount the injector in a motorized rotational system, enabling measurements of the sprays at precisely defined angles of observation. The DBI-EI technique requires a light source radiating uniformly in a certain range of an angle. Because of the diffuse radiation, an error in the quantification of the liquid phase results from the detection of multiple and forward scattered photons. This leads to an underestimation of the optical depth (OD), which further results in a false calculation of the projected liquid volume. Therefore, the authors must assume that DBI-EI results are wrong. To enable the use of DBI-EI in all spray regions independent of the measurement setup, they present a simulation-based method, which is correcting the OD for scattering effects. Results show, that the measured OD of the experimental setup, which was used in this work, is underestimated by at least a factor of 2.2. This factor increases with increasing spray densities. The authors can use the corresponding corrected PLV data to reconstruct three-dimensional data of the liquid volume fraction with the tomographic method filtered back projection. Thus, they obtain time and spatial resolved quantitative spray information, with an approach to correct undesired scattering effects, while keeping the experimental effort low.]]></description>
      <pubDate>Fri, 22 Dec 2023 11:19:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2287605</guid>
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