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This SAE Aerospace Recommended Practice (ARP) specifies the minimum design and qualification test recommendations for aircraft wheel overpressurization release devices used with tubeless aircraft tires to protect from a possible explosive failure of the contained inflation chamber due to overinflation.
A-5A Wheels, Brakes and Skid Controls Committee
The focus of this SAE Aerospace Standard (AS) is the integration of thermally actuated pressure release devices, hereafter referred to as fuse plugs, with the wheel and brake assembly. It does not address the manufacturing, quality, or acceptance test requirements pertaining to the production of these fuse plugs. It establishes minimum design, installation, qualification, and operational requirements for fuse plugs which are used only in tubeless tire-type aircraft braked wheels. Fuse plugs are designed to completely release the contained inflation pressure from a tubeless tire and wheel assembly when brake generated heat causes the tire or wheel to exceed a safe temperature level. The objective is to prevent tire or wheel rupture due to brake generated heat that could cause an unsafe condition for personnel or the aircraft. Refer to FAA Advisory Circular (AC) No. 23-17C; 14 CFR Part 25.735 (j); FAA AC No. 25.735-1; FAA AC No. 25-7D; EASA Certification Specifications for Large Aeroplanes (CS-25) 25.735 (j); and AMC 25.735.
A-5A Wheels, Brakes and Skid Controls Committee
This specification covers a corrosion-resistant steel in the form of sheet, strip, and plate.
AMS F Corrosion and Heat Resistant Alloys Committee
Autonomous vehicles face constraints from multiple factors, including insufficient technological maturity, complex urban road network structures, and behavioral uncertainties of traffic participants. Consequently, their driving safety has not yet been fully verified and guaranteed. To address the gaps in existing research, such as the lack of spatiotemporal dimension-specific prediction and insufficient utilization of higher-level autonomous vehicle accident data, a Geographically and Temporally Weighted Regression (GTWR)-HOLT accident risk prediction model was constructed. This model integrates accident severity and frequency while accounting for spatial heterogeneity and temporal non-stationarity. Based on collision accident data from autonomous vehicles in California, USA, for the period 2021-2023, and integrating multi-source data including road networks, Points of Interest (POI), and population, this study conducts empirical research by dividing the study area into spatiotemporal grids with a spatial step of 2 km × 2 km and a temporal step of one quarter. GTWR analysis of the first ten quarters of data shows a Mean Absolute Error (MAE) of 0.05, with predicted values closely matching the trend of the actual values, effectively capturing the variation patterns of risk. Commercial POI density, educational POI density, and population density consistently exhibit positive effects on accident risk. The risk prediction results for the eleventh quarter using the HOLT exponential smoothing model yield an MAE of 0.08. The results indicate that medium-high risk areas are likely to maintain their current risk levels in the near term. Predictions for low-to-medium risk areas and some high-risk areas perform well, and the predicted regression coefficients largely follow the trends of the original coefficients. The research provides data-driven support in formulating regulatory strategies for traffic management authorities and algorithm improvement measures in complex scenarios for vehicle manufacturers.
Wu, Shaoping, Hou, Yi, Dong, Chunjiao, Lu, Zhenzhen, Lai, Zhijian, Wen, Hang
Due to the rapid growth in ride-hailing services and the steady expansion of urban rail transit networks, understanding the complex interaction between the two is important. Most existing studies only focus on the overall competition and cooperation effects. Few scholars discuss local spatial differences and how the built environment works in detail. To investigate the spatial heterogeneity of built environment factors between the ride-hailing and the subway systems by situation and location, our study categorizes 3.71 million ride-hailing trips into three types: Proximal-to-Station Trip (PST), Medial-to-Station Trip (MST), and Distal-to-Station Trip (DST). We employed the values of built environment factors per grid as independent variables, and the grid-based volume of each ride-hailing trip category (PST, MST, DST) as the dependent variable. Additionally, we conducted analysis mainly with the multi-scale geographically weighted regression model (MGWR). We found that ride-hailing trips and subway trips have competition, cooperation, or complementarity relationships, which depend on trip purposes and public transit accessibility. Besides, we think that this relationship relies on the built environment, and it also shows clear spatial heterogeneity. The impact of different built environment factors has significant variation and spatial heterogeneity: Catering, Shop, and Bus Stop continuously trigger the demand for ride-hailing services, while Residence generally reduces the use. In PST, Enterprise, Medical, and Residence inhibit ride-hailing due to the high subway accessibility. In DST, these functions conversely boost ride-hailing usage due to limited bus coverage. These findings provide crucial insights for smart transportation management, multi-modal, and location-specific strategies to boost sustainable urban transportation development.
Zhao, Shiya, Xiao, Lingling
The high-speed rail network plays a crucial role in the development of the national economy and national defense, and assessing its resilience is of great significance for ensuring transportation safety and supporting emergency decision-making. To address the limitations of traditional complex network models in capturing multifaceted, higher-order interactions, this paper constructs a high-speed rail transport hypernetwork model based on hypergraph theory and evaluates the resilience of the high-speed rail transport hypernetwork from two dimensions: hypernetwork structure and hypernetwork function. By conducting experiments on the sequential failure of design nodes, this study compares the performance evolution and resilience boundaries of high-speed rail transport supernetworks under scenarios involving random and targeted attacks, thereby providing a theoretical basis for optimizing the resilience of high-speed rail transport networks. This study focuses on the high-speed rail network in the middle reaches of the Yangtze River and conducts an empirical analysis based on data from 1,085 high-speed rail services operating on October 22, 2025. The results indicate that structural resilience is superior to functional resilience, and that networks exhibit greater resilience against random attacks than against targeted attacks. A small number of core nodes handle the network’s primary functions; if they fail, network performance will decline significantly. Attacks based on betweenness centrality are the most destructive, while those based on sub-hypergraph centrality are relatively the least destructive. Hypergraph-based hypernetworks can effectively account for the operational relationships among high-speed trains, capture the association patterns between nodes, and provide a more accurate theoretical approach for modeling high-speed rail transport networks. This paper employs hypergraph theory to construct a hypernetwork of high-speed rail transportation, taking full account of the operational relationships among high-speed train services to enhance the accuracy of research on network resilience. This paper provides a theoretical framework for assessing and enhancing the resilience of high-speed rail networks and is of great significance for promoting the sustainable development of the railway sector.
Du, Hongwei, Tu, Min
The objective of this study is to examine the effects of wind-driven rain pressure loads on the structural reliability of low-rise buildings under extreme weather conditions. Pressure sensors, rain sensors, and wind measuring devices were installed on the surfaces of representative low-rise building samples. Load characteristics, including load magnitudes, distributions, and variation tendencies, were measured under different wind speeds, directions, and rain intensities over long periods, with correlation analysis carried out for all relevant parameters between loads and meteorological factors. A mechanical modeling framework was developed that takes into account uncertainty associated with wind-driven rain pressure loads, materials, and structural geometries. Failure probabilities and reliability indices were calculated for different critical structural components using reliability theory, with a focus on potential modes of failure and reliability deterioration due to fatigue. Based on the above investigation, optimal design guidelines were proposed, and their feasibility was confirmed by several engineering applications.
Zhang, Yutong
Accurate and real-time traffic state prediction is fundamental to optimizing urban traffic control and improving the service quality of online mapping platforms. While data-driven deep learning methods have shown promise in handling large-scale data, most existing approaches suffer from limitations due to their reliance on simplistic modeling components that cannot fully capture complex and multi-scale spatiotemporal dependencies. Unlike prior studies that predominantly utilize static graph structures or sequential processing, this research addresses the challenge of modeling dynamic correlations by proposing a Spatiotemporal Parallel Fusion Network. The theoretical framework of this study integrates graph spectral theory with advanced attention mechanisms to model both the physical and semantic topology of traffic networks. The proposed methodology features a multi-source spatial modeling framework that fuses a static connectivity graph, an inverse distance weighted graph, and a flow similarity graph via multi-relational graph convolution. This approach allows for the simultaneous capture of physical connectivity and dynamic traffic patterns. Furthermore, utilizing a parallel architecture, the temporal modeling component integrates multi-head self-attention with two-dimensional causal dilated convolutions. A cross-attention fusion module is further introduced to dynamically regulate spatiotemporal interactions. Comprehensive tests conducted on four practical traffic datasets indicate that the introduced model significantly outperforms thirteen cutting-edge benchmark methods. The study confirms that the proposed multi-graph strategies and parallel architectures effectively reduce mean absolute error and root mean square error, validating the efficacy of the proposed solution for the advancement of intelligent transportation systems.
Chen, Lulu
With the development of intelligent transportation systems, roadside video perception is expanding from traditional detection and tracking to higher-level measurement outputs, such as inter-target distance and target speed. These measurements are important for traffic flow estimation, accident warning, and timely responsibility assessment after incidents. Monocular cameras offer low cost, easy deployment, and wide coverage, but recovering reliable 3D scale from 2D pixels remains difficult; therefore, achieving stable monocular ranging and speed estimation under practical deployment constraints is still challenging. In this paper, we propose a roadside monocular vision–based method for target ranging and speed measurement. By combining a 3D object detection approach with coordinate transformation, the method outputs real-world target coordinates and speeds in the scene. We conducted several experiments, and the results show that our method can obtain target spatial coordinates and speeds in surveillance settings with reliable performance.
Chen, Ziyi, Lu, Mingfeng, Li, Lan, Pang, Yi, Chen, Yue, Yan, Tianyang, Zhang, Feng, Hu, Weidong
Structural displacement is an important quantity in Structural Health Monitoring (SHM), as it directly reflects the condition and safety of structures. Vision-based measurement methods have been widely studied in recent years, mainly because they allow non-contact sensing and can cover relatively large areas. When these methods are applied to Unmanned Aerial Vehicle (UAV) platforms, however, additional challenges arise. In practical operation, platform motion and attitude changes tend to introduce drift into the measurements, which can noticeably affect the final results. In this study, a displacement measurement approach that combines vision sensing with a laser reference is investigated for both UAV-based and fixed-camera scenarios. A laser source installed on the ground projects a reference spot onto the structural surface, placed close to a multi-circle target. This setup provides a stable reference point that is less affected by platform movement. The displacement is then estimated by tracking the relative motion between the target and the laser spot, instead of relying directly on absolute measurements. With this design, a large part of the motion caused by the platform can be separated, allowing the structural displacement to be expressed in a ground-based coordinate system. The implementation includes several practical steps, such as adaptively selecting regions of interest, performing basic image processing, refining feature locations at the subpixel level, and updating scale factors during operation. Experiments with both UAV and stationary camera setups show that conventional measurements are strongly affected by low-frequency drift, while the laser-referenced results remain relatively stable across different measurement points. According to the Root Mean Square (RMS) analysis, about 77%–95% of the drift caused by platform motion can be reduced under UAV conditions. These results indicate that the method can serve as a practical option for displacement monitoring in UAV-based vision applications.
Li, Zheng, Xu, Junhao, Hua, Yuansheng
As auto-driving technologies advance, the driver monitoring system (DMS) has shifted from a premium option to a standard feature of passenger vehicles. However, the compatibility and coordination between the DMS and the main active safety functions (ASF) of vehicles, such as automatic emergency braking (AEB), forward collision warning (FCW), lane departure warning (LDW) and lane keeping assistance (LKA), have been rarely studied. To fill this research gap, this study first categorized unsafe driving risks into three levels, which serve as a quantitative basis for DMS activation; Then, a novel collaboration model between DMS and ASF is constructed, which outputs dynamic ASF adjustment strategies based on the driver’s status. A multi-dimensional quantitative evaluation indicator system is then constructed to assess the effectiveness of the proposed model and the corresponding strategies. Moreover, controlled tests are performed to verify the model’s effectiveness, and validation tests are performed to confirm that it cannot only enable adaptive optimization of the warning timing and intervention intensity of ASFs, but also balance safety redundancy and driving experience. This study realizes coordination between the DMS and vehicles’ ASFs and provides a reference for optimized design of safety functions of intelligent vehicle safety systems.
Liu, Jiajie, Yang, Guhan, Zhang, Cheng, Ma, Wenbo, Wang, Botong
Multi-factory scheduling presents notable challenges when road congestion exhibits temporal variability, as transport lead times deviate from predefined production plans and schedules deemed feasible at the planning stage may become unfeasible upon dispatch initiation. This study, therefore, addresses the problem through an integrated pipeline of traffic prediction, traffic parameterization, and joint scheduling, which links traffic prediction with scheduling within a unified decision framework rather than treating them as two separate tasks. Link-speed data from the Q-Traffic dataset are utilized to train a Light Gradient Boosting Machine (LightGBM) short-horizon predictor; the predicted speeds are converted into a bounded congestion factor, and a route-wise aggregation method is applied to derive the traffic correction coefficient at the factory-customer-route-time level. Traffic information is incorporated into the scheduler via transport-time adjustments and delivery-related penalty terms, thereby incorporating traffic information without substantially changing the original scheduling structure. At the decision layer, each order is treated as an independent agent, and each scheduling action is defined by the ternary set (factory, route, dispatch time window). The decision layer is trained under the framework of Centralized Training with Decentralized Execution (CTDE) by adopting Multi-Agent Proximal Policy Optimization (MAPPO), a method that mitigates the weak local optima commonly generated by stage-wise planning strategies. Comprehensive experiments, including main performance tests, ablation studies, and robustness analyses, are conducted on small, medium, and large problem instances as well as on low, medium, and high congestion groups. Across all experimental settings, the integration of parameterization and MAPPO joint decision-making achieves a favorable trade-off among total cost, on-time delivery rate (OTD), and average delivery delay, while maintaining stable performance amid traffic congestion fluctuations. Predictor accuracy, reproducible experimental configurations, and summarized results are also reported to support the replication and reuse of the proposed method in traffic-aware production-transport coordination scenarios. In comparison with stage-wise planning and heuristic Earliest Due Date (EDD)-based baselines, the augmented MAPPO policy yields lower overall costs and higher OTD values on large-scale instances. Ablation results further demonstrate that it modulates the learned preferences for routes and time windows in scheduling decisions. Decentralized inference of the proposed model remains in the millisecond range across all tested problem scales, which validates the practicality of the model for rolling-horizon decision support in real-world operations.
Cai, Jiayu
This paper proposes a reinforcement learning-based multi-section, coordinated variable speed limit control approach for expressways. The method handles joint speed-limited decision-making at coupled spatiotemporal traffic dynamics across multiple sections and lanes. The traffic state space is constructed based on indicators: lane flow, speed, occupancy rate, number of slow-moving vehicles, and minimum Time-to-collision (TTC). Lane-level speed limits for each control unit are defined as action variables. A weighted reward function is designed to consider operational efficiency, safety, rationality of speed gradient, and control response. The model integrates Convolutional Neural Networks (CNNs) and Gated Recurrent Units (GRUs) to capture spatial correlations and time-varying properties in traffic-state information. In addition, a risk-aware dual-policy output mechanism is introduced to adaptively balance safety-oriented and efficiency-oriented control objectives. Using the Houjie-Xinlian section of the Guangshen Expressway as an example, three control strategies are simulated on the SUMO platform: CGDQN, FCDQN, and an uncontrolled scenario. Experimental results show that the total reward for CGDQN exceeds that of FCDQN. CGDQN reduces vehicle queueing and slow-moving traffic across various scenarios, thereby decreasing the likelihood of traffic accidents. The results demonstrate that the proposed method achieves coordinated multi-section variable speed limit control on expressways under different conditions, and is both feasible and effective.
Zhang, Yuping, Xu, Tian, Ma, Lin, Lin, Siyu, He, Runjing, Yuan, Chenwei
In the terminal area, the integration of new aircraft (such as electric vertical takeoff and landing aircraft and unmanned aerial vehicle systems) with traditional manned aircraft poses a significant challenge to modern air traffic management systems. To overcome the limitations of traditional macro-delay indicators in identifying local sector risks, this paper constructs a dual-constraint mechanism for sector capacity assessment based on the AirTop simulation platform. This mechanism integrates key factors such as flight conflicts, average aircraft congestion rate, and controller workload to construct a comprehensive performance index. Based on this comprehensive index, this paper constructs a dual-constraint mechanism: on the one hand, it identifies physical abrupt changes in the sector flow efficiency evolution curve; on the other hand, it uses historical safety thresholds from traditional manned aircraft operations for benchmark anchoring. Through these two dual constraints, the safe saturation level of the sector is ultimately determined. Experimental results show that as the UAV integration rate increases from 0% to 30%, the terminal area capacity decreases non-linearly, from 79 flights/hour to 65 flights/hour. When the UAV integration rate is 10%, the mechanism successfully identifies a latent saturation flow of 5 flights/hour and corrects the hourly saturation capacity of the terminal area to 71 flights/hour. Furthermore, this paper applies a multi-sectoral collaborative flow reduction strategy based on set theory to deduplicate flight data, successfully eliminating 22.09% of redundant calculations and effectively avoiding excessive system adjustments caused by spatiotemporal coupling. This fusion method meets the stringent requirements of microscopic security and macroscopic efficiency, providing a solid theoretical foundation and practical technical support for refined capacity management of heterogeneous hybrid airspace in the future.
Wang, Tong, Yang, Lei, Peng, Ziming, Zhang, Yating, Yu, Jiangting
In order to reveal the industrial agglomeration pattern, multi-scale characteristics, and driving mechanism of the air-rail dual-hub regions, this study takes Guangzhou as an example to extract the universal patterns of this region type. Based on POI big data of 9 different types of industries, this study uses kernel density analysis, average nearest neighbor analysis, Ripley’s K function analysis, and spatial autocorrelation analysis to explore the agglomeration characteristics of various industries in the air-rail dual-hub regions. The results show that the industries have a “core-edge” spatial distribution pattern: high-value areas are mainly concentrated around Guangzhoubei Railway Station and Huadu Central Business District, and extend in a belt and bead chain along rail transit and main roads. The overall industries show significant agglomeration, and the intensity is gradient. The consumption-oriented industries are stronger (food and beverage service 0.306, accommodation service 0.331, shopping service 0.338); Culture and education services, enterprises, and sports and recreation services are relatively weak (0.433-0.489); The agglomeration is hierarchical in scale, and the dominant scale is between 1.92 km and 4.48 km, forming a multi-scale structure with the coexistence of “node attachment-mesoscale composite service circle-regionalized cluster superposition”; Industrial POI density is positively correlated with road network density, night light index and population density as a whole, showing the composite driving characteristics of “population support-traffic guidance-vitality enhancement”. The results show that the hub effect of the air-rail dual-hub regions has expanded from the agglomeration around the station to the multi-type composite organization mode of “circle-corridor-group”. The study provides a basis for the guidance of spatial planning in different types and scales of the air-rail dual-hub regions.
Zhang, Ruijie, Ouyang, Jie, Shen, Ziran, Xue, Weining
To investigate the safety margin of the Ro-Ro passenger ship (ROPAX) with low stability during turning operations, a four-degree-of-freedom coupled mathematical model was established. The results indicate that during turning maneuvers, the maximum heel angle of the ROPAX vessel significantly exceeds the steady state values specified and calculated by the International Code on Intact Stability 2008 (2008 IS Code). It is noteworthy that this excessive transient heel angle, which exceeds the steady state assessment framework adopted in conventional IMO regulations, often receives insufficient attention in practical engineering and operational evaluations. Nevertheless, its impact on safety is critical. This study provides crucial evidence for evaluating the maneuvering safety margin of the ROPAX vessel and offers a valuable reference for refining stability criteria and operational guidelines for actual navigation.
Wang, Honggui, Li, Yunting, Li, Jinge, Yang, Yong, Wang, Biao, Wang, Xinjian
In order to optimize the traffic organization design under the condition of human-vehicle interaction and solve the problem of a lack of intuitive decision-making basis in the existing scheme, this paper proposes an optimization method for traffic organization design based on BIM and simulation technology. Firstly, BIM modeling and parametric expression of traffic space and organizational elements are completed, ensuring the consistency and operability of design information. Secondly, combined with the simulation technology, the key spatial bottlenecks and index selection of multi-scheme dynamic replication are identified, and the advantages and disadvantages of different design schemes are comprehensively evaluated. Then, through the comparison of multiple rounds of simulation and test of the optimization scheme, the key performance indicators are selected for detailed analysis and evaluation. Furthermore, the TOPSIS method is used to analyze the results of each scheme, and the recommended design scheme is finally determined by considering multiple influencing factors. The experimental results show that the combination of BIM and simulation technology can effectively improve the design selection, identify and solve the spatial bottleneck in the design, optimize the traffic flow organization, and provide an important theoretical basis and practical reference for the traffic organization design under the condition of coexistence of people and vehicles. This study provides a framework for the combination of BIM and simulation for traffic organization design under the condition of coexistence of people and vehicles, which has important reference significance for improving the design selection effect and reducing the operation risk.
Ye, Xiongfeng, Liu, Shaobo
This paper proposes a distributed cooperative control framework to address the stability control problem of connected and automated vehicle (CAV) platoons encountering external cut-in vehicles. To maintain platoon cohesion under cut-in scenarios, an active topology reconfiguration approach based on both the predecessor-following (PF) topology and the leader-following (LF) topology is first designed. By designating the first vehicle behind the cut-in vehicle as the new leader and combining with the LF topology, it is ensured that vehicles ahead of the cut-in can access the state information of those behind it, thereby maintaining platoon cohesion. Secondly, a model predictive control system is developed to adapt to the topology changes. Its prediction model, optimization objectives, and safety constraints can all be switched according to the topology, ensuring both platoon cohesion and operational safety. Simulation results demonstrate that the proposed strategy effectively suppresses oscillations in inter-vehicle spacing and speed fluctuations caused by the cut-in vehicle, enabling rapid recovery and smooth control of the platoon, and performs significantly better than static topology strategies. This provides a reliable solution for cooperative platoon control in dynamic traffic environments.
Yao, Yuan, Yang, Lei, Liu, Yafei, Liu, Fan, Sun, Zhanbo
To enhance the scientific rigor and accuracy in detecting voids beneath cement concrete pavements in civil airports, a three-dimensional finite element model consisting of 3 × 3 slabs was established using finite element software based on the Winkler foundation model. The mechanical responses of the slab edge region under loading from the Heavy Weight Deflectometer (HWD) were systematically simulated. In this model, both the load transfer capabilities of various joint conditions — namely good, medium, secondary, and poor — and the configuration of voids beneath the slab were taken into account. The variation patterns of key mechanical indicators, including deflection value and deflection ratio, were analyzed. The results indicate that poorer joint load transfer capacity leads to larger deflection values and deflection ratios at the slab edge, whereas the deflection within the slab interior is less influenced by joint load transfer capacity. The model was validated using measured deflection data from multiple airports, demonstrating strong reliability and applicability. This study provides a theoretical foundation and technical reference for identifying voids beneath airport cement concrete slabs and for supporting maintenance decisions.
Wang, Yuxiang, Ren, Hui, Zhang, Ruya
While previous studies have examined road network morphology and POI distribution separately or at single scales, this study introduces a multi-scale analytical framework to investigate their intrinsic correlation in historic urban contexts. Employing the sDNA model and kernel density estimation within ArcGIS, this paper quantitatively analyzes the road network morphology and spatial distribution characteristics of Points of Interest (POI) in the historic urban area of Kaifeng City, and examines their correlation across multiple spatial scales (400 m to 3000 m radii). The results show that: (1) At different spatial scales, the arterial road system in the historic urban area of Kaifeng demonstrates high topological integrity and centrality; (2) The correlation between the road network morphology and POI spatial distribution in the historic urban area weakens with increasing radius. At the same scale, road proximity is more likely to influence the distribution of POI; (3) At the slow-moving scale, the correlation between road network morphology and POI spatial distribution is stronger than at the vehicular scale, and it gradually weakens with increasing radius. These findings reveal a scale-dependent relationship between road morphology and functional agglomeration, suggesting that the vitality core of historic urban areas remains anchored in pedestrian-oriented networks — a theoretical insight with implications beyond the Kaifeng case. The research results can provide a basis for traffic improvement and facility planning in the historic urban area of Kaifeng, and serve as a reference for other historic urban areas. The multi-scale analytical framework demonstrated in this study offers a transferable methodology for diagnosing similar scale-dependent dynamics in diverse historic urban contexts.
Rao, Minglei, Liu, Yanzhong, Zhai, Feifei, Zhang, Yangyang, Zhang, Jingsi
To address the difficulty in quantitatively evaluating the effectiveness of traffic organization schemes in highway reconstruction and expansion projects, this study proposes an evaluation system integrating traffic safety and operation efficiency. By combining VISSIM simulation with SSAM conflict analysis, this study verifies the effectiveness of the proposed evaluation method through a case study of the Guihua Interchange on the Chengnan Highway. For traffic safety evaluation, a safety risk assessment model is constructed, consisting of four first-level indicators (road, traffic, facilities, and management) and fifteen second-level indicators, along with a four-level risk classification standard. For operational efficiency evaluation, the Level of Service (LOS) and average delay are adopted for quantitative assessment. Simulation experiments are conducted on the three-stage traffic organization scheme for the Guihua Interchange in the Chengnan Highway reconstruction and expansion project. The results show that the comprehensive risk scores of the three-stage scheme are 12, 12, and 13, respectively, all classified as general risk. The peak-hour delay rates of the first and second stages are both lower than 6 s/(veh·km), verifying the feasibility of the temporary ramp and truck diversion strategy. The third-stage simulation indicates that the conflict rate of the east-south ramp reaches 0.58 conflicts/(veh·km) (93.5% of which are lane-changing conflicts). It is suggested to add graphical path indication traffic signs, paint no-lane-changing markings on the inner lanes, and guide ramp traffic flow in advance. The research demonstrates that the proposed evaluation system can effectively support the feasibility judgment, optimization path identification, and dynamic evaluation verification of traffic organization schemes, significantly improving the safety and approval efficiency of reconstruction and expansion projects.
Qin, Lang, Wang, Yue, Chen, Qingyu, Liu, Gang
In April 2025, the International Maritime Organization (IMO) held the 83rd session of the Marine Environment Protection Committee (MEPC) in London, the United Kingdom. During this crucial meeting, extensive discussions and in-depth negotiations were carried out regarding the mid-term greenhouse gas (GHG) reduction measures under the newly proposed Net-Zero Framework (NZF). The NZF establishes a medium-term regulatory framework featuring a dual compliance structure consisting of basic and direct compliance. Its core components include the Greenhouse Gas Fuel Standard (GFS), the Greenhouse Gas Emissions Pricing (GEP), and Flexible Compliance (FC). Among these, the GFS is positioned as the core regulatory instrument, given that it directly governs the carbon intensity of marine fuels, thereby providing the foundational driver for the industry's transition towards zero or near-zero fuels and technologies (ZNZs). The implementation of this framework will systematically restructure the entire industrial chain of international shipping, including marine power system research and development, new-type ship design and construction, green fuel production, storage, supply, bunkering and certification, seafarers' professional training, as well as daily shipping operation and management. It will inevitably bring about profound and far-reaching impacts on the technological route, investment layout, operational mode, and competitive landscape of the global maritime industry. Against this background, this paper focuses on the NZF, systematically clarifying its formulation background, core institutional components, and practical operational mechanisms. Taking an 86K bulk carrier as the research object, this study carries out a detailed case analysis to reveal the actual challenges and response pathways for shipowners and operating enterprises under the new regulatory system. On this basis, this paper further proposes targeted coping strategies and practical reference suggestions for the shipping industry to adapt to and comply with the upcoming NZF requirements, so as to provide decision support for the sustainable and low-carbon development of the maritime sector.
Li, Zichao, Jian, Yanjun, Zhao, Jiawen, Fu, Xiaming, Dong, Lina, Lu, Chunhui