Abstract:In the current domain of air traffic, frequent flight conflicts and departure flight delays within airport systems are increasingly becoming key factors that affect the efficiency of flight operations and passenger satisfaction. In light of this, the present study aims to explore the collaborative sequencing problem of departure flights within airport systems. By considering the resource constraints of airport systems, the concept of "departure flight satisfaction" is introduced. The objectives of optimization include minimizing the total delay of departure flights, maximizing the sum of average satisfaction across all flights in airports, and minimizing the overall measure of fairness within the airport system. A collaborative sequencing model for departure flights in the terminal area of airport clusters is established, and an elitist strategy-based non-dominated sorting genetic algorithm is designed to solve the Pareto optimal solution for the collaborative sequencing problem of departure flights in the terminal area of airport clusters. An empirical analysis was conducted using the terminal areas of three airports in the Beijing-Tianjin region as examples, validating the effectiveness of the proposed model and method. The experimental results show that compared to the first-come-first-served scheme, the total flight delay was reduced from 7,796 seconds to 5,029 seconds, a decrease of 35.3%, with the average delay per flight dropping from 159 seconds to 103 seconds. The average satisfaction of flights reached 0.7867, and the overall measure of fairness among airports in the cluster was 0.0044. The proposed optimization method can significantly reduce the total delay of departure flights in airport systems, improve overall flight satisfaction, and achieve the fair and efficient use of resources.

Abstract:【Objective】To delve into the temperature effect of sustained summertime heat on the bridge-mounted CRTS III type ballastless track, this research aims to offer scholarly guidance for the enhancement of seamless track line design, operational maintenance, and remedial strategies for bridge-mounted ballastless track systems.【Method】Based on the principles of thermodynamics and the mechanics of beam-slab-rail interaction, a refined thermo-mechanical coupling model for the bridge-mounted CRTS III type ballastless track seamless lines has been established to simulate the temperature field, longitudinal forces, and displacement variations of the track structure components under sustained high-temperature conditions ranging from 2 to 10 days.【Results】

Abstract:【Objective】Studying the issue of excessive vibration in high-rise buildings located in the test track area of subway depots.【Method】Through on-site measurement and finite element simulation of the environmental vibration before and after the vibration reduction transformation of a subway vehicle testing line, the vibration source and the vibration transmission law of the upper cover before and after the vibration reduction transformation are analyzed.【Result】The results indicate that the influence of vehicle speed on the dominant frequency of the source intensity affects the level of vibration transmitted to various floor slabs. The vibration measured in bedrooms is relatively large under the condition of 60km/h, while the vibration in living rooms is more significant under the condition of 40km/h. The vibration first decreases, then increases, and finally decreases again as the distance from the vibration source increases. While the steel spring floating slab reduces vibration, noise may be slightly amplified, with all vibration measurement points at the vibration source reduced by more than 10dB after the modification, but the noise at the 7.5m measurement point increased by 0.96dB. By comparing and observing the changes in vibration levels at different frequencies with floor height before and after the vibration reduction modification, it is found that the maximum frequency band of vibration acceleration level shifts forward, from 25-40Hz before the modification to 20-25Hz after, which is related to the change in excitation frequency at the vibration source.【Conclusion】Compared to conventional ballast beds, the steel spring floating slab after vibration reduction modification can significantly reduce vibrations, enabling the buildings constructed above the test track area of this depot to meet the corresponding regulatory requirements.

Abstract:【Objective】The impact of high-speed trains on urban green technology innovation is an important research direction in the study of the impact of high-speed trains on regional innovation. In order to study the impact of high-speed railway on the "quality and quantity" of urban green technology innovation, 【Method】this paper establishes a multi-period DID model and discusses how high-speed railway operation affects urban green technology innovation based on the panel data of 41 cities in the Yangtze River Delta urban agglomeration from 2004 to 2019. 【Result】The results show that the operation of high-speed trains can effectively improve the "quality and quantity" of urban green technology innovation in the Yangtze River Delta. Through the mechanism test, the opening of high-speed trains can affect urban green technology innovation by strengthening economic agglomeration and venture capital; The operation of high-speed trains has the heterogeneity of city size and region, and the operation of high-speed trains has a significant impact on large cities and small and medium-sized cities. 【Conclusion】This study systematically expounds the connection between the operation of high-speed trains in the Yangtze River Delta region and the "quality and quantity improvement" of urban green technology innovation, and the conclusion is still valid after the robustness test.

Abstract:【Objective】To compare and analyze the resilience of route networks in terminal areas of different airports within an airport cluster. 【Method】This study uses the Guangzhou terminal area and the Zhuhai approach terminal area as examples, applying complex network methods to construct route network models for each. The network topology is analyzed in detail using indicators such as node degree, degree distribution, betweenness centrality, clustering coefficient, network diameter, and average path length. Based on this analysis, node importance is identified using degree centrality, betweenness centrality, and the KBKNR algorithm. Additionally, scenarios of random attacks and deliberate destruction are designed, and network efficiency and connectivity are used as metrics to evaluate the resilience of the route networks.【Results】The experimental results show that under random attacks, the Zhuhai Terminal Approach Air Route Network demonstrates greater resilience compared to the Guangzhou Terminal Air Route Network. Conversely, under intentional attacks, the Guangzhou Terminal Air Route Network exhibits stronger resilience. Moreover, degree centrality attacks are more likely to cause network collapse compared to betweenness centrality attacks, indicating that nodes with high degree centrality should be prioritized for protection as critical nodes.【Conclusion】This study can help identify critical waypoints or air routes and implement corresponding protection measures, thereby improving the operational efficiency of flights in terminal areas.

Abstract:【Objective】To investigate the dynamic response of reinforced concrete columns under impact, 【Method】relying on the two-degree-of-freedom mass-spring-damper model and combining with the OPENSEES computing platform, on the basis of clarifying the equivalent resistance-displacement curve of reinforced concrete columns, a simplified impact analysis method for reinforced concrete columns integrating material nonlinearity and impact strain rate effects is proposed. By comparing with the drop hammer impact test of reinforced concrete columns, the validity of the proposed two-degree-of-freedom simplified analysis method is verified. On this basis, the impacts of sensitive parameters like impact velocity, impact mass, axial compression ratio and longitudinal reinforcement ratio on the drop hammer impact response of reinforced concrete columns are explored. 【Result】The results showed that the peak impact force calculated by the proposed simplified analysis method has a deviation of approximately 4.30% from the test value, and the deviation of the peak displacement at mid-span is approximately 2.16%. With the increase of the impact velocity and impact mass, the peak impact force and the peak displacement at the mid-span of the column gradually increased, but the increase of the impact velocity and impact mass would lead to a delayed characteristic of the peak displacement at the mid-span of the column. With the increase of the axial compression ratio and the longitudinal reinforcement ratio, the peak impact force of the column gradually increased, while the peak displacement at the mid-span showed a gradually decreasing trend. Moreover, the change of the longitudinal reinforcement ratio had a significantly greater influence on the secondary impact in the impact force time history curve than the change of the axial compression ratio. 【Conclusion】The proposed simplified analysis method can accurately predict the impact dynamic response of reinforced concrete columns

Abstract:【Objective】To study the variation laws of horizontal displacement of foundation pit retaining piles and surface settlement outside the pit under limited soil conditions.【Methods】This article conducted excavation model tests on a foundation pit with semi infinite soil on one side and finite soil on the other three sides.【Results】We obtained the variation laws of internal force, deformation, and surface settlement of retaining piles under excavation of finite soil foundation pits, and further analyzed the relationship between the horizontal displacement of retaining piles and surface settlement in finite soil foundation pits.【Conclusion】The results show that the horizontal displacement of the retaining pile body is positively correlated with the soil width B, and the reduction of soil width can effectively reduce the horizontal displacement of the retaining pile top and body; The maximum value of surface settlement increases first and then decreases with the increase of soil width B. In the case of limited soil width, soil width has a significant impact on surface settlement outside the foundation pit, and there is a critical value for soil width B; The maximum bending moment of the retaining pile body is positively correlated with the width B of the soil, and the width of the soil has little effect on the position of the maximum bending moment; The ratio of the maximum surface settlement outside the finite soil foundation pit to the maximum lateral displacement of the retaining structure, δ vm/δ hm, is between 0.9 and 1.85 and shows a decreasing trend with the increase of B. Among them, the δ vm/δ hm on the finite soil side of the foundation pit is greater than 1. Therefore, when designing and constructing finite soil foundation pits, more consideration should be given to the surface settlement outside the pit.

Abstract:【Object】In order to explore the vibration characteristics of high-speed train gearbox housing under the coupling excitation of wheel polygon and rail corrugation.【Method】The rigid-flexible coupling dynamic model of wheelset, gearbox housing and track was established. Three vibration acceleration sensors were arranged in the gearbox housing, and dynamic simulation was carried out under different working conditions to analyze the vibration acceleration of each measuring point of gearbox housing.【Result】Under the wheel-rail coupling excitation, at the same speed, when the wheel polygon is 23 order and the amplitude is 0.01 mm, the root mean square value of the vibration acceleration of each measuring point is the largest, and the wheel polygon has the greatest influence on the measuring point B in the three measuring points. Under the excitation of rail corrugation, the root mean square value of vibration acceleration of measuring point B is the largest among the three measuring points under the combined action of harmonic torque of traction motor and gear meshing. The root mean square value of vibration acceleration of measuring points A and C increases with the increase of amplitude. Compared with the wheel-rail coupling excitation with broad spectrum, the vibration frequency caused by wheel-rail excitation is close to the fifth order natural frequency of the gearbox housing, which induces resonance.【Conclusion】The resonance can be avoided by changing the speed of the train or changing the structure of the gearbox. This study provides a reference for the design of the gearbox structure.

Abstract:【Objective】To investigate the impact of surface surcharge on the settlement of adjacent tunnels, 【Method】a two-stage analysis method was adopted. In the first stage, the Boussinesq solution calculates the vertical additional force exerted on nearby subway tunnels due to surface surcharge. In the second stage, the subway tunnel is modeled as an Euler beam supported on the Pasternak foundation, simplifying the structural representation. Utilizing the Rayleigh Ritz method, functional expressions for each system component are formulated, leading to the establishment of the total energy equation. The control equation is subsequently solved through the application of the variational principle. 【Result】The obtained results are compared to measured data to validate the effectiveness of the proposed method. The research explores the impact of offset distance (d), tunnel burial depth (z), surcharge (p), and surcharge range (B and L) on settlement. 【Conclusion】The research findings indicate a significant impact on settlement within the range of (0.5-1) L directly below and on both sides of the surcharge; As d increases, the maximum settlement of the tunnel gradually decreases; There is a linear relationship between p and wmax and the larger the pile surcharge, the greater the maximum settlement; Increasing L and B initially leads to gradual settlement increase, followed by stabilization. L exerts a greater influence on wmax compared to B.

Abstract:Remote sensing image object detection has a wide range of applications in intelligent transport, such as dynamic monitoring of road network operation status, intelligent law enforcement on roads, and intelligent monitoring of road disasters. Due to the characteristics of small and dense targets, large scale changes, and arbitrary direction distribution in remote sensing images, general object detectors have poor detection performance when directly applied to remote sensing images. To address these challenges,this paper proposes a remote sensing image object detection algorithm based on improved Retinanet. First, the model introduces Improved Downsampling Module (IDM) on the base feature extraction network ResNet50, which performs multiple down-sampling processing on features, and then dynamically selects the spatial receptive field using the convolution kernel selection mechanism to model the multi-scale semantic information of the scene. Finally, the classification and regression results of the target object are obtained. Experimental results show that the proposed method improves the mAP by 3.2% on the large-scale remote sensing image object detection dataset DOTA compared to the original Retinanet network, enabling more accurate localization and identification of remote sensing targets.