In an AC system with parallel operation of electricity-hydrogen micro-grids, when adopting traditional control methods, the difference in output line impedance will affect inverters, and large circulating currents occurs such that a reasonable distribution of active power become inaccessible. Given the relationship between the voltage deviation and the active power, the active power distribution between multiple micro-grids is analyzed. Firstly, the AC system model of the electric-hydrogen hybrid energy-storage micro-grid is constructed, including photovoltaic, battery, fuel cell, and electrolyzer. Secondly, following the relationship between the active power and the voltage in the reverse droop control, a reverse droop control based on power following control is proposed to work out voltage deviation and auto-adjust the rated active power. Finally, within a parallel operation of electric-hydrogen micro-grids, the proposed method is compared with other methods and is verified by hardware-in-the-loop experiments on the platform of RT-LAB. The experimental results show that the proposed method outperforms other methods: the accuracy of power distribution after stabilization is 97.50%, the accuracy of the bus voltage is 99.86%, and the circulating current mostly ranges in [−3.0, 3.0] A.

A switched system is a class of complex systems that integrate a series of continuous or discrete subsystems and switching mechanisms. State-dependent switching systems have not been studied in depth due to complexity. Therefore, the modeling of state-dependent switching systems is explored through the input-output trajectories of the systems. The data mining technique is used to find useful information between data and establish a more specific and explicit representation between inputs and outputs. On this basis, a framework is proposed to segment the data according to the switching time of the identified trajectory, build the subsystem model by neural network to fit its switching rules, deeply mine the information of the state-dependent switching system, and obtain the information between the subsystems and subsystems in the switching system. The experimental results show that compared with the modeling of traditional mechanism, the proposed data-driven method reduces the modeling complexity by 17.3%.

In order to study the distribution of current circulation and potential of the train’s body–axle end of the dual-system train in different power supply system sections, the chain circuit model of the train grounding system was established based on a dual-system train, and a united traction power supply calculation method was proposed for the vehicle-ground integration in alternating current (AC) and direct current (DC) sections. At the same time, the optimization model of train grounding protection resistance was established, and two configuration schemes of the train grounding system were analyzed. A dual-system rail transit line in China was studied for simulation verification. The research results show that compared with scheme 2, scheme 1 can reduce the maximum potential value of the train’s body–axle end by 36.58%–41.04% and the maximum current circulation value by 18.49%–22.97%. In addition, scheme 1 sets the protection resistance at the first and last vehicles at 20 mΩ, which can achieve a maximum potential value of the train’s body–axle end of 1.15 V and a maximum current circulation value of 50.30 A. It can reach the optimal effect of restraining the potential of the train’s body–axle end. The united traction power supply calculation method for the vehicle-ground integration in AC and DC sections can be applied to grounding system analysis of power supply single-system or multiple-system trains.

Relationship is explored between the wire shape and concentrated load of catenary messenger wires in static and vibrational states. The parabola method is used to determine the messenger wire shape in static state. By constructing the differential equation and using the Fourier transform, the messenger wire shape in vibrational state is calculated. Combined with the force analysis, the concentrated load formula of the messenger wire in static and vibrational states is deduced according to Newton's second law. After acquiring the displacement at the concentrated load in static and vibration states, the concentrated load is solved, and its measurement method is tested on the vibration measurement platform built in lab. The test results show that the percentage of absolute error in static state is 0.20%, and in vibrational state with main vibration frequencies of 1 Hz and 2 Hz it is within 0.50%. It is feasible to use machine vision to obtain the static position and vibration displacement data at the concentrated load, and thus realize the contactless measurement for the concentrated load of messenger wires.

Chaotic systems have the characteristics of nonlinearity, pseudo-randomness and sensitivity to initial values, which provides an anchor to construct S-boxes based on dynamic system and secures block encryption algorithms. At present, most chaos-based S-box construction methods is designed to optimize single performance index, making it hard to improve the overall performance. To solve this, a new S-box design method is proposed by combining chaotic mapping and multi-objective genetic algorithm. Firstly, the initial S-box population is generated according to the characteristics of chaotic mapping; then, nonlinearity and difference uniformity of S-boxes are optimized under the framework of the genetic algorithm. According to the characteristics of the S-boxes, the exchange operation is introduced into the optimization algorithm, and a new mutation operation and calculation of non-dominated ordered sets are designed, effectively improving the nonlinearity and difference uniformity of the S-boxes. The experimental results show that the difference uniformity of the generated S-box is 6 and its nonlinearity is at least 110, demonstrating an improvement in the overall performance of the S-boxes.

In order to enrich the dynamic characteristics of a low-dimensional discrete chaotic system and overcome the problem of low security of chaotic image encryption system caused by the introduction of deoxyribonucleic acid (DNA) coding, a 2D discrete chaotic system with constant positive Lyapunov exponent was constructed based on Arnold map. In addition, a chaotic image encryption scheme was designed by combining the system with DNA coding. The designed chaotic system model did not have nonlinear terms and had hyperchaotic dynamic behavior. The chaotic sequence used for encryption in the encryption scheme was the result of addition and module operation between the plaintext image pixels and the key. Images were divided into blocks by the size of 4 × 4. The operations of DNA addition and subtraction, XOR, and XNOR in the diffusion algorithm were based on DNA coding rule 1, rule 4, and rule 7, respectively. The simulation and performance analysis results show that the key space of the encryption scheme is 2²⁶⁶; the information entropy is 7.999 3 bit; the key sensitivity is 10⁻¹⁵, and the average number of pixel change rate (NPCR), unified average change intensity (UACI), and block average change intensity (BACI) are 99.609 2%, 33.466 4%, and 26.771 8%, respectively.

Breast ultrasound images have large intra-class differences, small inter-class differences, and complex and variable nodule shapes. In order to address these issues, a breast ultrasound image algorithm with morphological feature recalibration was designed to realize automatic diagnosis of breast ultrasound. First, an end-to-end network model was built, which adopted progressive training to fully learn the more discriminative regions in the image and obtain more fine-grained feature information. Secondly, a partition shuffle mechanism was proposed to reduce the noise caused by the disruption of the nodule region when the image was shuffled. Then, the features extracted from the bottom layer of the model were recalibrated with the morphological features obtained through the mask image, and a low-scale recalibration loss function was proposed. Finally, in order to verify the effectiveness of the proposed method, a low-scale recalibration database (LSRD) containing 1 550 breast ultrasound images was constructed. The experimental results show that the accuracy of the proposed model on LSRD is 94.3%; the sensitivity is 91.2%; the specificity is 93.6%, and the area (AUC) under the receiver operator characteristic curve (ROC) is 0.941, all of which are superior to other comparison models. On the breast ultrasound image (BUSI) dataset, compared with the other models, the classification accuracy of the proposed model is improved by 3.3%.

Most of existing synthetic aperture radar (SAR) image generation methods fail to generate SAR images and their detection labels simultaneously. A position-based conditional generative adversarial network (PCGAN) is constructed for SAR ship image generation and target detection. Firstly, ship position information is used as a constraint and a detection label to restrict its position in the generated image. Then, the Wasserstein distance is further introduced to stabilize the training process of PCGAN. Finally, the generated SAR images and their corresponding labels are applied for the end-to-end training of YOLOv3, so as to realize the cooperative learning of data enhancement and ship detection, and further obtain the diversified ship data more coupled with the practical application of ship detection. Experimental results conducted on HRSID dataset illustrate that PCGAN can generate clear and robust SAR ship data, and the accuracy of ship detection can be improved by up to 1.01%, thus verifying the proposed method.

In satellite communications, leveraging adaptive beamforming technology can significantly improve the anti-jamming ability of navigation receivers. However, conventional adaptive beamforming algorithms are sensitive to model mismatch. In order to overcome the performance degradation of conventional adaptive beamforming algorithms arising from both the steering vector mismatch of the desired signal and the covariance matrix mismatch, a new robust adaptive beamforming algorithm is proposed. Firstly, the signal-to-noise ratio (SNR) of the desired signal is estimated. Then, the projection matrix is constructed with the estimated SNR to further predict the steering vectors of the desired signal and those of the interferences. Next, the steering vectors of the desired signal and the interferences are corrected by using the uncertainty-set optimization method. Finally, the signal power is estimated and the interference-plus-noise covariance matrix is reconstructed. The simulation results show that, compared with the beamforming algorithm that requires covariance matrix reconstruction, the proposed algorithm achieves a better output signal to interference and noise ratio (SINR) performance. When SNR is 10.0 dB and signal direction of arrival (DOA) mismatch occurs, the output SINR gain is about 1.9 dB; when wavefront distortion arises, the output SINR gain is about 1.5 dB; when coherent local scattering happens, the output SINR gain is about 1.6 dB.

Distributed optical fiber vibration sensor based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) has important application prospects in railway perimeter security. In order to reduce the influence of inherent interference fading in Φ-OTDR on phase demodulation and improve the recognition rate of disturbance signals, an interference fading suppression method based on moving vector rotating average (MVRA) was proposed. Firstly, the detected signal was characterized by a complex vector, and the complex vector signals at each position were rotated and aligned according to their initial phase angles. Then, the moving average method was used to improve the signal-to-noise ratio by mitigating the fluctuation of the signal amplitude and reducing the power of the detected noise, thereby suppressing interference fading. Next, the disturbance signal was demodulated from the suppressed fading signal. MVRA was compared with spectrum extraction and remix (SERM) and digital phase-shift transform (DPST) methods, and the anti-fading effect was verified by the standard deviation of the differential phase. Finally, an experimental platform for distributed optical fiber perimeter intrusion detection was built to simulate four kinds of protective disturbance signals, including environmental noise, stress damage, climbing, and net shearing. The demodulated phase grayscale image was taken as the feature image, and then a convolutional neural network was used for pattern recognition. The experimental results show that MVRA can suppress fading more efficiently than SERM and DPST. When the sliding window length is 50 ns, the signal-to-noise ratio is improved by 11.2 dB, and the recognition rate of disturbance signals is increased from 88% before fading suppression to 92% after fading suppression.

Interferometric synthetic aperture radar (InSAR) is greatly affected by ionospheric delay, especially at low and high latitudes, which decreases the number of available interferometric pairs for time-series InSAR and the monitoring accuracy of low-frequency SAR systems. To this end, the reformulating range split spectrum interferometry (RRSSI) was introduced for the ionospheric error estimation and correction in time-series InSAR. The performance of the proposed method was tested by ALOS-1 PALSAR images covering the Anaktuvuk River area in Alaska from June 2006 to August 2010. The experimental results show that the proposed method can effectively estimate the ionospheric errors of time-series InSAR results and is sensitive to ionospheric disturbances at small spatial scales. After correction, the average annual deformation rate in the study area decreases from 1.46 to 0.49 cm/year, and the standard deviation from 1.16 to 0.65 cm/year, indicating an improvement in monitoring accuracy. Additionally, the cumulative deformation of the selected time-series points becomes more stable than the large fluctuation before correction, which is more consistent with the real deformation.

Aiming at the transformer fed by cascaded H-bridges with carrier phase-shifted (CPS) sinusoidal pulse-width modulation (SPWM), a fast method is proposed to calculate the iron loss on the basis of the classical loss separation model. Firstly, the lumped duty cycle of the SPWM voltage waveform is defined, and the analytical model for modulation ratio is derived. Secondly, based on the classical loss separation model and the lumped duty cycle, the iron loss calculation model is built for CPS-SPWM cascaded H-bridge. The method can directly use the modulation ratio, DC bus voltage, and other parameters to calculate the iron loss, thus avoiding the harmonic analysis or numerical integration process in conventional methods. Then, based on the proposed iron loss model, an equivalent simulation method is proposed for the iron loss under the SPWM voltage excitation. With this method, the relative error of iron loss is less than 3.6% and the used time is reduced by 74.5%. Finally, the proposed method is verified by experiments and the maximum calculation error of iron loss is less than 7.6%.

In order to simulate the motion process of the levitation system of high-speed maglev trains and analyze the system response under different conditions, it is necessary to establish a levitation system model and conduct controller design and simulation analysis. Firstly, the basic structure and working principle of the levitation system of high-speed maglev trains with the joint structure as the basis unit were introduced. The mathematical model of the levitation system under ideal conditions was derived through a mechanism analysis method. Then, the levitation system model was simplified reasonably, and a nominal controller was designed for the simplified model. Finally, the control effect of the nominal controller was verified through simulation, and the levitating and landing processes of the permanent magnet and electromagnetic hybrid levitation system under simulation and experimental conditions were compared. The results show that the variation of physical quantities such as levitation gap and levitation current obtained from the simulation coincides with the trend of the actual system, with an error of less than 5% during static levitation.

The existing hybrid drive technology is mainly based on the hybrid power of oil electricity or liquid, and it aims to improve the energy utilization rate of conventional fuel vehicles and reduce fuel consumption and emissions. Based on the high power density and energy regeneration advantages of hydraulic technology, the electro-hydraulic hybrid powertrain can achieve efficient energy utilization within the full-speed operating range, increase the power density of pure electric drive system, and effectively improve the driving range of electric vehicles and cycling life of batteries. This paper summarizes the progress, current situation, and development trend of research on electro-hydraulic hybrid powertrain configuration, energy recovery technology, energy release mode, and control strategy and analyzes the feasibility and application prospect of using electro-hydraulic hybrid configuration and advanced energy management strategy to improve the power performance and energy utilization rate of pure electric vehicles. According to the existing research results, the vehicle equipped with an electro-hydraulic hybrid powertrain can reduce energy consumption by about 40% at most, which has significant advantages in efficient energy utilization. For an electro-hydraulic hybrid powertrain, hydraulic energy regeneration, coupling, and release are closely related to driving scenarios and motor operating conditions. The research should focus on solving key technologies such as power coupling, regenerative braking, and energy management, so as to improve the overall performance of the powertrain, especially the power density and energy-saving characteristics.

In order to investigate the influence of different ground motion inputs on the seismic isolation of a long-span soft arch bridge, the response law of the bridge structure under near-field and far-field ground motions was analyzed by nonlinear finite element model, and the optimal arrangement scheme of the bridge bearings was obtained. Firstly, based on modal analysis, the difference in dynamic characteristics between the bridge and the traditional reinforced concrete (RC) arch bridge was compared. Secondly, the records of near-field ground motions with different pulse periods, near-field pulseless ground motions, and far-field long-period ground motions were selected. Finally, the response behavior and damage evolution path of the arch bridge under near-field and far-field ground motions were studied, and the design scheme of the bridge’s seismic isolation bearing was optimized. The research results show that the structural responses of the bridge under near-field pulse and far-field long-period ground motions are larger than those under pulseless ground motions. The envelope curves of shear force and bending moment of high pier columns were distributed in an S shape under longitudinal and vertical ground motions. A plastic hinge is prone to form in the middle of the pier body, and the effect of high-order vibration mode is significant. The longitudinal direction of the bridge first encounters seismic damage, followed by the transverse direction, and the damage paths are successively low column, high pier column, and solid-hollow section of arch rib. The friction pendulum bearing embodies the most excellent seismic isolation performance with larger displacement. High damping bearing scheme fails to avoid damage under near-field middle and long pulse period ground motions and far-field long-period ground motions. The laminated-rubber bearing scheme can not form a quasi-seismic isolation system because it cannot guarantee the synchronous sliding of the bearing. The hybrid scheme consisting of high damping bearing and friction pendulum bearing leads to small bearing displacement, with arch rib and pier column in an elastic state, which is the optimal seismic isolation scheme for long-span soft RC arch bridge in the near-fault regions.

In order to study the dynamic response characteristics of long-span highway-railway cable-stayed bridges with broken cables under the dynamic actions of wind and train, an actual cable-stayed bridge was taken as the research object, and a 3D computational model of the whole bridge was established. The nonlinear implicit dynamic time history algorithm was used to analyze the dynamic response of the whole bridge in the case of sudden cable breaking. The dynamic response of the bridge structure and the train running on the bridge under different sudden cable breaking conditions was studied under the coupling effect of the train and bridge. In addition, the dynamic response of the bridge structure and the train running on the bridge under the coupling effect of wind, train, and bridge was discussed when the structure was in a static equilibrium state after a few cables were broken. The nonlinear explicit dynamic time history algorithm was used to study the cable breaking and falling state under the action of lateral wind. The results show that long-span highway-railway cable-stayed bridges have high safety redundancy, and it is only possible for continuous cable breaking and collapse to occur when more than 12 longer cables of the mid-span break. When a single cable breaks, the maximum increase in dynamic stress for the remaining cables is approximately 100 MPa, which has a minor impact on the safety of the bridge structure. When a sudden cable breaking occurs while a train is running on the bridge, it will cause a noticeable change in the acceleration response of the train, or in other words, the calculated maximum acceleration under various conditions is approximately 1.5 m/s². After the breaking of a single longest cable, the vertical displacement response of the train running on the bridge increases by less than 0.01 m, resulting in a small impact on the stiffness of the bridge, and the bridge can still accommodate train traffic. When the longest cable breaks, if the lateral wind speed reaches 30 m/s, it may cause the broken cable to fall into the upper deck lane of the girder, invading a distance of approximately 5 m, which affects the safety of traffic on the upper deck lane.

To analyze the effect of a void under the existing pipeline on its deflection response during tunnel undercrossing construction, a theoretical model and an analytical solution of the uncoordinated deformation of the existing pipeline and soil induced by tunnel undercrossing construction were presented. Firstly, the existing pipeline was regarded as an Euler beam on a tensionless Pasternak foundation. According to the contacting condition of the pipeline and soil, the equations for the uncoordinated deformation control of the pipeline and soil caused by the tunnel undercrossing construction were established, and the corresponding formulas for the pipeline deflection were derived. Secondly, the influence of the parameters on the length of the void under the existing pipeline was discussed by using the proposed theoretical method, including the vertical soil pressure acting above the void, the flexural stiffness, and the width and maximum value of the formation settlement trough at the position where the existing pipeline located. Finally, a normalized empirical formula was proposed for calculating the length of the void under the existing pipeline induced by tunnel undercrossing construction, further simplifying the calculation method of existing pipeline deflection induced by the undercrossing construction of new tunnels. The research results show that the length of the void under the existing pipeline has a good correlation with the two normalized parameters (the ratio of the stiffness of the existing pipeline to the foundation, as well as the ratio of the vertical soil pressure acting above the void of the existing pipeline to the maximum value of the formation settlement trough), and the correlation coefficient between the calculated value of the fitting formula and the theoretical data is close to 1.

To analyze the effect of a void under the track slab on the rail deformation of a ballastless railway caused by tunnel undercrossing, an improved calculation method was proposed to predicate the tunnel undercrossing-induced rail deformation of the ballastless railway. Firstly, the rail of the ballastless railway was simplified as a dual subgrade beam model, and the governing equation was established for the rail deformation of ballastless railway caused by tunnel undercrossing. Then, the ballastless railway was divided into three parts including the middle section above a void and the two sections connecting with the subgrade, and the formulas for the rail deformation of the ballastless railway caused by tunnel undercrossing were derived. The proposed theoretical calculation method was verified by comparing the theoretically calculated and numerically simulated results of rail deformation of the ballastless railway caused by uneven settlement of the subgrade. Finally, the influences of parameters on the rail deformation of the ballastless railway were discussed, including the burial depth of the new tunnel, the ground loss rate caused by tunnel undercrossing construction, and the intersection angle between the railway and the tunnel. The results show that when the undercrossing tunnel is 6 m below the railway, the deformation at the midpoint of the rail reaches the maximum. When the ground loss rate caused by tunnel undercrossing construction increases from 0.25% to 2.50%, the deformation at the midpoint of the rail and the width of the void under the track slab increase by 4.0 and 2.2 times, respectively.

In order to study the effect of subway vibration on the dynamic response of different types of subway stations and their superstructures, three kinds of combination types, namely “soft combination”, “hard combination Ⅰ”, and “hard combination Ⅱ” were proposed based on the differences in the main bearing of the connection between the subway station and the superstructure. The train load spectrum was obtained by means of the vehicle-rail coupling model, and a numerical simulation model of the subway station-superstructure was established using finite difference software FLAC^3D and compared with measured data to verify the correctness of the model and the parameters. Finally, the vibration response of the superstructure under the three kinds of combination types was studied based on numerical simulation from the time domain and frequency domain. The results show that the acceleration peak from the station hall to the first floor of the superstructure decreases by 69.10% under the soft combination and 2.08% under the hard combination Ⅰ, but it increases by 2.94% under the hard combination Ⅱ. The vibration acceleration of the superstructure in the hard combinations is larger than that in the soft combination. The vibration frequency of the superstructure under the three kinds of combination types is mainly 40–90 Hz. In addition, for the same floor of the superstructures, the vibration decreases with the increase in the distance from the vibration source. The maximum acceleration level of the first floor of the superstructure under the soft combination is 68.2 dB, which has decreased by 11.3 dB compared with that of the station hall layers. The maximum acceleration level of the superstructure under the hard combination Ⅰ and hard combination Ⅱ is 83.4 dB and 79.4 dB. The first principal stress attached to the superstructure is very small due to subway vibration, and it attenuates quickly in the upward propagation process. From the station hall to the superstructure, the attenuation of the first principal stress of the soft combination is 85.81%, and that of the hard combination Ⅰ and hard combination Ⅱ is 63.46% and 72.27%, respectively. Furthermore, the spacer soil attenuates the additional stress obviously. It is suggested to choose the soft combination in the actual construction project of subways.

In order to ensure the smooth change of cable-strut internal forces before molding cable domes, a construction optimization method is proposed, focusing on alternately lifting the inner ring and tensioning the outermost diagonal cables. The lifting height of the inner ring is first optimized for minimizing average structural strain energy in the construction process. The cable-strut internal forces and nodal displacements from simulation are compared with those from the construction method with the tensioned outermost diagonal cables. The results show that, alternately lifting the inner ring and tensioning the outermost diagonal cables can effectively reduce the cable-strut internal forces by 61.83%, avoiding sharp fluctuation of cable-strut internal forces before molding. It causes more gentle change of structural configuration with 1.43 m maximum vertical displacement difference between adjacent construction steps, and low average structural strain energy of only 55.03%, which demonstrates its remarkable optimization effect. Thus, the proposed method is applicable to the construction simulation of cable domes.

The CPⅢ network of high-speed railways is a resection surveying network with free station observation and automatic observation, enabling simultaneous edge and angle measurements. The separability of gross errors between observations is not only related to the design space of the control network but also affected by observation space factors such as automatic observation of the total station. Therefore, the gross error judgment equation (GEJE) was used to obtain the design space correlation of the separability of multidimensional gross errors of observations in the CPⅢ network. By considering the characteristics of automatic observation of total station during data acquisition in the CPⅢ network, the temporal correlation of observations was introduced. The reliability relationship between observations was extended from the traditional consideration of design space effects to the comprehensive evaluation of both design space and observation space effects. The law of multidimensional gross error separability in accordance with the actual measurement of the CPⅢ network was obtained. Then, the Monte Carlo method was used to demonstrate the correctness of the separability of multidimensional gross errors in the CPⅢ network considering the observation space information. The results show that the reliability of CPⅢ observations will be affected by the observation space, which should be considered in the practice of gross error detection. The observations of each edge in the CPⅢ network have gross error detectability and identifiability. At most two gross errors in one edge can be detected and located in the three edges of the same target. If there is no error in the observation station, at most 2⌊n/2⌋ gross errors in ⌊n/2⌋ edges can be detected and located among n edges of one observation station observing n targets.

One of the key problems in the construction of the electrification reconstruction project of Gela section of Qinghai−Xizang Railway is to ensure the frost jacking stability of the pile foundation of the overhead contact system mast (OCSM). In order to study the anti-frost jacking performance of piles with different sections (equal-section circular pile (Z1), straight-cone cylindrical pile (Z2), and curved-cone cylindrical pile (Z3)), the indoor model tests with three freeze-thaw cycles were carried out by using the subgrade filling materials of Qinghai-Xizang Railway as the test soil sample. The distribution laws of ground temperature, pile-top displacement, and pile body stress of the OCSM pile foundations under the influence of freezing and thawing were obtained. The test results show that the freezing (thawing) of the subgrade is two-dimensional, and the depth of freezing near the OCSM pile foundations is about 30 cm. The vertical frost-heave displacement at the subgrade shoulder is 4.30 mm, and the vertical frost jacking displacement of Z1 is 0.26 mm. In addition, the vertical frost jacking displacement of Z2 and Z3 is only 46% and 58% of Z1, respectively. The top of the three piles has a horizontal displacement of about 0.1 mm. During the freezing process, the pile is under tension as a whole, and the axial force is greatest near the depth of freezing. The maximum value of tangential frost-heave stress occurs near the ground surface. The total tangential frost-heave force of the curved-cone cylindrical pile is the smallest, with the best anti-frost jacking effect.

As an effective waterlogging control measure, deep storage tunnel systems have air pocket retention during the inflows of multiple shafts, causing issues like pressure surges and threatening the safety of system operation. According to the deep storage tunnel project of Suzhou section, a dual-shaft and single-tunnel system model is constructed. Numerical simulations are carried out with computational fluid dynamics methods and verified by water filling experiments, while the pressure surges of entrapped air pocket under different inflow conditions are analyzed and the variation law is summarized. The results show that under the design inflow condition, the maximum pressure of 3.5% entrapped air pocket can reach 35.36 m, which is 1.77 times of the static pressure of the shaft at the control water level. When the total inflow of shafts is constant, the flow distribution has little effect on the pressure. With symmetrical inflow, the extreme pressure is the largest, which is 3% and 6% larger than the unilateral inflow respectively. In case of symmetrical inflow, with the increase of total inflow, the maximum pressure of air pocket first increases and then stabilizes, and compared with that of 29 m³/s total inflow, it increases by about 30%, corresponding to the total inflow of 116 m³/s.

When the traditional Monte Carlo sampling method is applied to complex reliability problems such as small failure probability, there are some shortcomings such as low efficiency and limited accuracy. To solve this problem, a spherical layer sampling analysis method is developed. Firstly, by dividing the distance and direction parameters, the standard normal random vector is reconstructed, and its standard normality and mutual independence are verified. Thereafter, based on a layered sampling strategy, the standard normal space with the radius beyond first order reliability index is divided into multiple spherical layers, which are then sampled by the reconstructed vector layer by layer. Combined with the full probability formula, a spherical layer sampling algorithm is developed to estimate the structural failure probability. Finally, three typical examples are taken as objects of interest, and the performance of the algorithm is verified through comparative analysis. The results show that, the proposed algorithm has high sampling efficiency and convergence performance, and the error of calculation results is within 3%. Compared with other algorithms, its estimation variance is smaller, and it can effectively solve complex reliability problems such as multiple design check points. The algorithm has advantages in sampling efficiency, scope of application, and stability, and is more suitable for solving and analyzing the reliability of actual complex structures.

In order to clarify the effect of temperature on the layered mechanical properties of carbon fiber wires, while the critical temperature is considered, the gravitational strain distributions of each wire layer, strand and section in the breaking force conditions are calculated at temperatures driven by different voltages of an electric heating. The results show that, above the critical temperature, the carbon core is subjected to positive stress and the aluminum strand to a negative stress, making the wire unable to bear the breaking force. The maximum stress and strain of each strand appear at both ends of the wire, and the stress and strain at the chamfer position are slightly larger than the stress on the main body of the strand. The maximum stress at each wire cross-section is positive and occurs at the core, and near the end where the force acts it drops sharply. Carbon fiber wires are more suitable for various temperatures, but the changes in the mechanical characteristics at the clamping position at wire ends and at the small and medium trapezoidal sections need more exploration.

In order to study the calculation method of the compression bearing capacity of the inclined members of the transmission tower with joint constraints, the failure mode, bearing capacity, and deformation form of the arranged minimum axis and parallel axis of 120 equal angle steels were obtained through eccentric compression bearing capacity tests. In addition, the influence of different joint stiffness and joint types on their bearing capacity was studied. Combined with the current industry specifications, the calculation formula of the slenderness ratio of inclined members of transmission towers is proposed for different joint types (A, B, C). The results show that when the slenderness ratio is less than 120, the bearing capacity of the member is mainly controlled by eccentricity. A larger eccentricity indicates a lower bearing capacity. When the slenderness ratio is greater than 120, the bearing capacity of the member is mainly controlled by the joint stiffness. Larger joint stiffness indicates higher bearing capacity. A and C joint types have their own advantages at different slenderness ratios, but the bearing capacity of B joint type is always lower than that of A and C joint types. There is a great deviation between the calculated value of Chinese and foreign codes and the test value, and these codes have certain limitations, which are reflected in the insufficient eccentricity correction of small slenderness ratio members and insufficient joint stiffness correction of large slenderness ratio members. The calculation results of the proposed modified formula for slenderness ratio of inclined members are in good agreement with the test results and can be used to guide the engineering design.

Improper lane-changing may pose a threat to traffic safety, leading to traffic accidents and congestion. Therefore, it is necessary to explore lane-changing trajectories for different driving styles at lane exits. The trajectory data of vehicles from congested scenarios on Chinese highways and expressways was utilized, and drivers were categorized into cautious, normal, and aggressive types by using the K-means algorithm. According to cluster analysis and lane-changing time prediction, the minimum sum of lane-changing longitudinal displacement and weighted driving stability was pursued, and comfort and safety evaluation metrics were employed as constraints. A quintic polynomial was utilized for optimal lane-changing trajectory planning. Then, a genetic algorithm was employed to solve the trajectory planning problem. Based on the simulation platform comprising Prescan, CarSim, and MATLAB/Simulink, a two-degree-of-freedom vehicle dynamics model of joint longitudinal and lateral control was designed. Finally, three typical lane-changing scenarios, including the car in front of the vehicle, the car in front of the target lane, and the car behind the target lane were designed. The effects of lane-changing trajectory planning and vehicle trajectory tracking control under different driving styles were evaluated by simulation experiments. The experimental findings demonstrate that the proposed trajectory planning algorithm, incorporating driving styles, extends the lane-changing time for aggressive drivers in scenarios with vehicles in the target lane. In addition, it reduces the lane-changing time for normal and cautious drivers, ensuring timely, safe, and comfortable lane-changing maneuvers.