Line Sections Research Articles

Optimizing Bus Bridging Service Considering Passenger Transfer and Reneging Behavior

This paper addresses the design of bus bridging services in response to urban rail disruption, which plays a critical role in enhancing the resilience and sustainability of urban transportation systems. Specifically, it focuses on unplanned urban rail disruptions that result in temporary closure of line sections, including transfer stations. Under this “transfer scenario”, a heuristic-rule based method is firstly presented to generate candidate bus bridging routes. Non-parallel bridging routes are introduced to facilitate transfer passengers affected by the disruption. Meanwhile, the bridging stops visited by parallel routes are extended beyond the disrupted section, mitigating passenger congestion and bus bunching at turnover stations. Then, we propose an integrated optimization model that collaboratively addresses bus route selection and vehicle deployment issues. Capturing passenger reneging behavior, the model aims to maximize the number of served passengers with tolerable waiting times and minimize total passenger waiting times. A two-stage genetic algorithm is developed to solve the model, which incorporates a multi-agent simulation method to demonstrate dynamic passenger and bus flow within a time–space network. Finally, a case study is conducted to validate the effectiveness of the proposed methods. Sensitivity analyses are performed to explore the impacts of fleet size and route diversity on the overall bridging performance. The results offer valuable insights for transit agencies in designing bus bridging services under transfer scenarios, supporting sustainable urban mobility by promoting efficient public transit solutions that mitigate the social impacts of sudden service disruptions.

Cause Analysis of Rail Corrugation in Metro Lines Based on System Vibration Characteristics

The mechanism of rail corrugation remains unclear, and the research methods require improvement. The vibration characteristics represent the system’s external manifestations, but a comprehensive analysis is still lacking. Taking the vibration characteristics of the wheel-rail system as a starting point, this study investigates the formation mechanisms of rail corrugation on measured metro lines. The line sections included both steel spring floating slab tracks and long sleeper embedded tracks. First, the wavelength and frequency attributes of rail corrugation were obtained through field measurements. Then, referencing line conditions, three-dimensional finite element numerical models were established, frequency response calculations were performed, and the relationship between the vibration responses of the wheel-rail system and rail corrugation was analyzed. Finally, a parameter sensitivity analysis of the wheel-rail system was conducted to control the further development of rail corrugation. The results show distinct corrugation phenomena on both inner and outer rails in the measured sections. The characteristic wavelengths of inner and outer rail corrugation on the steel spring floating slab track are 34 mm and 59 mm, respectively, and the characteristic wavelengths of inner and outer rail corrugation on the long sleeper embedded track are 46 mm and 47 mm, respectively. The frequency response analysis indicates that the numerical results exhibit eigenfrequencies close to the passing frequencies of the measured corrugations. The formation mechanism of inner rail corrugation on the steel spring floating slab track is attributed to the third-order bending vibration of the wheelset, which leads to the generation of inner rail corrugation. In contrast, the formation mechanism of outer rail corrugation is attributed to the lateral bending vibration of the outer rail. For the long sleeper embedded track, inner rail corrugation is generated by the lateral bending vibration of the inner rail, while outer rail corrugation results from the lateral bending vibration of the outer rail. Appropriate adjustments to the fastener’s vertical and lateral stiffness, as well as the steel spring’s vertical and lateral stiffness, can shift the rail corrugation eigenfrequencies, thereby inhibiting the development of corrugation with the original wavelength. Changes in other parameters have no effect on the rail corrugation eigenfrequencies and only influence the development speed of corrugation with the original wavelength. This research effectively elucidates the cause of rail corrugation from the system vibration perspective and provides a valuable complement to the corrugation analysis method.

FIELD TESTING OF THE ROUTE TRACING METHOD FOR FULLY DIELECTRIC OPTICAL CABLE

The article presents a method of underground dielectric optical cable route tracing using a distributed acoustic sensing based on recording and analyzing of the phase-sensitive optical reflectometer response to vibration-acoustic effects in the proposed tracing area. The peculiarity of the method is the use of pulsed impact for approximate determination of the cable laying area and the use of an acoustic source to determine the direction and clarify the location of the tracing route. The study outlines tracing algorithm and recommendations for choosing acoustic impact parameters. In ac-cordance with the method elaborated, field tests were carried out on the section of a fiber-optic communication line made using a fully-dielectric optical cable. In result of the experimental testing, the possibility to determine a cable route tracing location under conditions of electromagnetic and acoustic interference with an error of not more ± 0.2 m was demonstrated.

Experimental measurement of track irregularities in EMS maglev systems using the mid-chord offset method and inverse filtering technology

Track irregularities are the main factors causing changes in suspension stability and vibrations in EMS (Electro-magnetic Suspension) maglev trains. Due to the scarcity of actual measurement data on EMS maglev track irregularities, this paper utilizes the principles of the mid-chord offset method to develop a track irregularity detector with a 1-m test chord length. Tests were conducted on the maglev line in Qingyuan, Guangdong. Based on the “using small to predict large” algorithm, data simulating a 3-m test chord length were output. The experimental data were processed to remove trend items and outliers, and an inverse filter was designed to counteract the amplitude gain error of the mid-chord offset method, obtaining accurate data on vertical and lateral track irregularities. The results show that the amplitude and power spectral density (PSD) fluctuations of track irregularities on the left and right rails of the measured line section are similar, with height irregularities of 2.5–3 mm and alignment irregularities of 1–1.5 mm. Periodic wavelength components related to the longitudinal spacing of sleepers, rail length, and beam span, such as 1.2 m, 6.5 m, 12.5 m, and 25 m, are evident, highlighting the need for enhanced inspection and maintenance of these structural components in engineering projects.

Design and Rapid Optimization Procedure of a Compact Broadband Microstrip Diplexer for VHF/UHF Band

ABSTRACTIn this paper, a design procedure of a compact broadband microstrip diplexer working on the Very High Frequency (VHF)/Ultrahigh Frequency (UHF) band is proposed. The diplexer consists of a fourth‐order Butterworth Low‐Pass Filter (LPF) and a sixth‐order elliptic High‐Pass Filter (HPF). The two filters are located on two substrates with a common ground. A microstrip‐to‐coaxial structure is utilized to transmit the power flow between the two substrates. For miniaturization, the utilized ideal capacitors and inductors are realized by the commercial lumped‐element capacitors and the curved microstrip line sections, respectively. All the middle design and rapid optimization processes from the schematic simulation by Advanced Design System (ADS) to the circuit simulation by CST STUDIO SUITE (CST) are given in the article. A prototype is fabricated and measured. The testing results are consistent with the simulation. The diplexer can operate at 225–775 and 880–2500 MHz. The insertion losses are 0.8 ± 0.3 and 0.9 ± 0.4 dB in the two working bandwidths. The isolation bandwidth of −20 dB level is as small as 105 MHz. The roll‐off is also sharp that the related bandwidths corresponding to the attenuation level −3 to −20d B are 90 and 30 MHz to the high and low bands, respectively. Besides, the return loss and isolation are larger than 10 and 20 dB approximately. The diplexer has a volume of 0.065 λg × 0.156 λg @775 MHz, which can be utilized to feed the miniaturized broadband VHF/UHF antenna system.

The Prosperity of the Silk Road Qinghai Road during the Wei Jin Southern and Northern Dynasties

Qinghai Road is an integral part of the overland Silk Road and an auxiliary passage of the Hexi Corridor, the main road. During the Wei Jin Southern and Northern Dynasties, the Central Plains was still in turmoil, and Qinghai Road once replaced Hexi Road because of its safety and convenience, and became the main line of the eastern section of the Silk Road, and all kinds of people were constantly on the Qinghai Road.

PSO-FDM (Particle Swarm Optimization-Finite Difference Method)-Based Simulation Model of Temperature and Velocity of Full-Scale Continuous Annealing Furnace

Improving the accuracy of the temperature field prediction model for continuous annealing line strips and enhancing the model’s adaptability to full-size strips are key technical challenges in continuous annealing lines. This paper developed a continuous annealing temperature prediction model based on a variable step-size strategy for the heating section, even-heat section, slow-cooling section, and fast-cooling section of the continuous annealing line. To improve the prediction accuracy for different strip sizes, the PSO optimization algorithm was employed to determine the optimal heat transfer coefficient for each strip size. Additionally, due to the limited production of certain strip gauges, providing insufficient data for optimization, this study introduces a combined file approach to address gauge vacancies. The experimental results indicate that the optimized model with variable step size can control the absolute prediction error to less than 4 °C, improving prediction accuracy by 61.9% and prediction speed by 26.8% compared to the traditional equal-step prediction model. This study verified that the merger method is effective for addressing side gauge vacancies, while the proposed method is suitable for resolving middle gauge vacancies. The main technical contribution of this study is the establishment of a high-precision prediction model for continuous annealing temperature of variable step length strips, ensuring high temperature control accuracy for full-gauge strips when passing through the continuous annealing production line.

How do morphological characteristics affect tidal asymmetry in the Radial Sand Ridges?

While it is widely recognized that the Radial Sand Ridges (RSR) in the South Yellow Sea are predominantly shaped by tidal forces, there remains a limited understanding of how this distinctive morphological configuration—characterized by an interlaced channel-ridge system—can subsequently influence local tidal dynamics. This study examines the effects of morphological features on tidal asymmetry, taking into account seabed slope, relative depths between ridges and channels, and channel convergence. Three principal indices—namely tidal-duration-asymmetry (TDA), peak-current-asymmetry (PCA), and slack-water-asymmetry (SWA)—are employed to quantify various dimensions of tidal asymmetry. The findings indicate that SWA serves as the most morphology-sensitive indicator, whereas TDA exhibits minimal sensitivity to morphological changes. Furthermore, seabed steepness emerges as a critical factor influencing tidal asymmetry within the RSR; steeper slopes enhance intrinsic energy conversion processes, thereby inducing tidal asymmetries. Additional analysis reveals that streamwise advection accounts for an average of 88 % of total advection scale while controlling for spatial heterogeneity. Specifically, the average integral sum of advection terms along submerged sand ridges is 2.53 times greater than that along the deepest section of the tidal channel line—a significant contributor to spatial variability in SWA. With a positive seabed slope, the apex of the RSR acts as a source for overtides which interact with incoming astronomical tides, consequently generating tidal asymmetries. Moreover, this study illustrates varying dependencies of tidal asymmetry on bottom stress across channels and ridges, contributing to spatial variability in arc direction among RSRs. Ultimately, this research elucidates complex interactions between tidal flow and morphological characteristics within RSRs and provides insights into tide evolution in analogous ebb-shoal systems.

3D Modelling and Measuring Dam System of a Pellucid Tufa Lake Using UAV Digital Photogrammetry

The acquisition of the three-dimensional (3D) morphology of the complete tufa dam system is of great significance for analyzing the formation and development of a pellucid tufa lake in a fluvial tufa valley. The dam system is usually composed of the dams partially exposed above-water and the ones totally submerged underwater. This situation makes it difficult to directly obtain the real 3D scene of the dam system solely using an existing measurement technique. In recent years, unmanned aerial vehicle (UAV) digital photogrammetry has been increasingly used to acquire high-precision 3D models of various earth surface scenes. In this study, taking Wolong Lake and its neighborhood in Jiuzhaigou Valley, China as the study site, we employed a fixed-wing UAV equipped with a consumer-level digital camera to capture the overlapping images, and produced the initial Digital Surface Model (DSM) of the dam system. The refraction correction was applied to retrieving the underwater Digital Elevation Model (DEM) of the submerged dam or dam part, and the ground interpolation was adopted to eliminate vegetation obstruction to obtain the DEM of the dam parts above-water. Based on the complete 3D model of the dam system, the elevation profiles along the centerlines of Wolong Lake were derived, and the dimension data of those tufa dams on the section lines were accurately measured. In combination of local hydrodynamics, the implication of the morphological characteristics for analyzing the formation and development of the tufa dam system was also explored.

A Method for Tracking an Underwater Pipeline from Stereo Images Using an Autonomous Underwater Vehicle

The problem of tracking an underwater pipeline (UP) is considered in the context of an inspection mission. It is assumed that the diameter of the cylindrical pipe is known. To solve this problem, a tracking method is proposed, based on searching and calculating the center line of the UP, and determining the relative position of the autonomous underwater robot (AUV) and UP in the coordinate system of the AUV camera. Unlike well-known analogues, in which the solution is based on recognizing and constructing the boundaries of the UP in images, the proposed method searches for the true position of the center line of the UP on a set of possible options by checking their veracity. Possible options for the spatial position of the search centerline of the current UP section are generated by varying the direction of the beam in the horizontal and vertical plane. The starting point of the ray is the end point of the centerline of the previous section. The veracity criterion is to check that the 3D point features constructed in the scene belong to the cylindrical surface of the UP. The generation and matching of pointfeatures in images of a stereo pair is carried out using the SURF detector. The choice of the correct direction of the center line of the current UP section is ultimately made by voting. The end point of the center line of the current section is determined taking into account the calculated common visibility area with the previous section of the UP. To evaluate the effectiveness of the method, computational experiments were carried out on virtual scenes. The effectiveness was assessed by the accuracy of UP localization (in the AUV coordinate system) and by the speed of calculations in comparison with: a) the first version of this method, based on the use of a vectorized form of images; b) analogues using the Canny and Hough Transform detectors. The stability of the method to the accumulation of navigation accuracy errors during long-term tracking of UPs was also assessed.

Зависимость потенциала на рельсах от сопротивления заземляющего устройства тяговой подстанции и параметров рельсовой линии

Purpose: to analyse the dependence of the potential on rails on the track coordinate at different values of conductivity of the grounding device of the traction substation (g0 = 0 S, 10 S, 25 S, 50 S). Methods: the analysis was carried out on the developed substitution diagram of the traction rail network section using the method of nodal potentials. The calculation was implemented in Mathcad 15 mathematical package. Selection of initial data was carried out taking into account the values established in the current normative documentation. Results: an equivalent substitution scheme of the traction rail network on a double-track section has been developed, in which each homogeneous section of the rail line is replaced by an equivalent U-shaped quadrupole. This allows to transform an electric circuit with distributed parameters into a circuit with concentrated parameters. If it is necessary to simulate transverse or longitudinal asymmetry of traction current in a section, such a section is replaced by a three-wire substitution diagram in which the earth conductor is taken into account. To improve the accuracy of the modelling results, the inter-track jumpers are taken into account, and the number of nodal potentials is increased to 7. It is established that the highest modulus value of voltage on rails is observed near the traction substation. It has been determined that the voltage value on rails near the traction substation decreases when the conductivity of the earthing device increases. Practical significance: values of rail-ground potential at different values of conductivity of grounding device of traction substation for tracks of both directions of traffic — even and odd tracks — are determined. The value of conductivity of the traction substation grounding device at which it is safe for the personnel to stay on the rails near the traction substation has been determined. The obtained results can be recommended for practical use in railway transport.

Application of UAV airborne LiDAR technology in highway engineering construction

Abstract The airborne LiDAR technology of UAVs is an efficient and high-precision spatial information acquisition technology. This paper introduces the airborne LiDAR technology of UAV in detail and studies the application of airborne LiDAR technology of UAV in highway construction based on the sixth section of the Leibokahalo-Yongshan connection line of G4216 Yibin Xinshi to Panzhihua Section. Engineering application practice shows that this technology can solve the difficult problem of obtaining basic geographic information data, and verify the rationality of the scheme and the matching degree with the field environment. In addition, compared with traditional survey technology, the technology has obvious advantages in the construction of highways in complex terrain, which helps to improve the quality of survey and design.

Algorithm 1046: An Improved Recurrence Method for the Scaled Complex Error Function

Calculation of the scaled complex error function \(w(z)\) by recurrence is discussed, and a new method for determining the number of steps required to achieve a given accuracy is introduced. This method is found to work throughout the complex plane, except for a short section of the real line, centred at the origin. An algorithm based on this analysis is implemented; Taylor series with stored coefficients are used to compute \(w(z)\) in a small region where recurrence is not efficient. The new algorithm is tested extensively and found to outperform earlier recurrence-based codes. It also performs favourably against recent codes based on other methods.

Comparison of corrosion behavior of primary/modified nickel slag with semi‐rebonded periclase‐chromite refractory

AbstractSemi‐rebonded periclase‐chromite refractories are commonly utilized in the working lining section of the molten pool in oxygen‐enriched top‐blowing furnaces for nickel production. Its resistance to nickel slag corrosion determines the safety and service life of the melting furnace. The composition of nickel slag influences the corrosion resistance of semi‐rebonded periclase‐chromite refractories. By comparing and analyzing specimens corroded by primary and modified nickel slag, the influence mechanism of w(CaO)/w(SiO2) variations on corrosion resistance of semi‐rebonded periclase‐chromite refractories was clarified. The results show that a spinel isolation layer is preferred to form at a lower w(CaO)/w(SiO2) ratio (< 0.576) and enhance the corrosion resistance of semi‐rebonded periclase‐chromite refractories. As the ratio increases, the slag viscosity falls and the corrosion products contain larger levels of Ca3Cr2Si3O12 and Ca3MgSi2O8, which prevent the creation of the isolation layer and establish a conduit for Ca2+ and Si4+ transport and reaction into the interior of the refractory.

Stability Study and Strengthening Strategy of Spiral Case-Encased Concrete Structure of Pumped Storage Power Station

With the development of global hydropower, the scale of hydropower stations is increasing, and the operating conditions are becoming more complex, so the stable operation of hydropower stations is very important. The vibration of the turbine unit will cause resonance in the powerhouse, and the structural stability of the powerhouse will be affected. Many scholars pay attention to the stability of the turbine unit operation, and there are few studies on the powerhouse of the hydropower station. Therefore, this paper relies on the Weifang Hydropower Station project to study key issues such as the tensile strength of concrete and how to arrange steel bars to increase the structural stability by changing the material properties through FEA. Three schemes are designed to evaluate the safety of the powerhouse structure when the turbine unit is running through the safety factor. Our findings indicate that the stress variation patterns observed on the inner surface of the powerhouse remain consistent across different operating scenarios. Notably, along the spiral line of the worm section, we observed that the stress levels on the vertical loop line decrease gradually with increasing distance from the inlet. Conversely, stress concentrations arise near the inlet and the tongue. Additionally, it has been noted that the likelihood of concrete cracking increases significantly at the tongue region.

Multi-granularity spatiotemporal object modelling of waterborne traffic elements

The electronic navigational charts are crucial carriers for representing the multi-source heterogeneous data of Waterborne Traffic Elements (WTEs). However, their layer-based modelling method has some shortcomings in expressing the multi-granularity features, complex relationships, and dynamic evolution of elements. This paper proposes an objectification modelling method for WTEs based on the concept of multi-granularity spatiotemporal object modelling. A classification system for waterborne traffic objects is developed based on the relevance of behavior to elements; combining characteristics of waterborne traffic, a data model for waterborne traffic objects is constructed from eight aspects: spatiotemporal reference, spatiotemporal position, spatial form, basic information, attributes, behavioral ability, structure, and associative relationships. An object extraction function is also established, extracting object attributes and relationships between objects according to different element classes. Taking the Jiashan section of the Hangzhou-Shanghai Line in Zhejiang Province as the experimental subject, the multi-granularity spatiotemporal characteristics, dynamic evolution, and relationship expression of channel class objects are tested. The experimental results show that the proposed method provides the theoretical basis and data organization mode for the multi-granularity expression of WTEs.

Direct prismatic coefficient variation to hull form surface

The initial ship design process aims to optimize the hull form to enhance ship efficiency. During this phase, hull form variations are executed based on a reference ship to meet shipowner requirements, such as altering the CP (prismatic coefficient) to adjust the section lines. Once these variations are made, a surface is generated. However, this iterative process can be time-consuming as the surface creation must be done manually each time. Thus, we propose a method to directly apply CP variation onto the hull form surface, setting the variated section line as a constraint. In this study, the proposed method is employed to modify the hull form surface to meet CP requirements. The section lines of the modified surface are then extracted to validate the results. This streamlines in the initial hull form design, reduces the overall design time, and yields high-quality hull form surfaces efficiently.

Исследование проводящих свойств двухгаммадионной согласованной конфигурации для проводящего участка передающей линии полоскового типа

The article presents the results of electrodynamic modeling of the conductive properties of a section of a strip type microwave transmission line containing a surface two-gammadion configuration of a sputtered conductive material. Research has shown the possibility of the emergence and use of rejection-selective properties of such a structure, as well as methods for controlling frequency and transmission parameters. The results obtained are of interest to developers of microwave range nodes.

Design of a broadband LNA with multifunction Circuitry based on composite right /left handed transmission lines for impedance matching and suppression of unwanted frequencies

This article presents a low-noise amplifier based on the use of a composite right-left handed transmission line consisting of a single microstrip line and a split ring resonator at the transistor input and output. This design ensures optimum matching over a wide frequency range while eliminating an unwanted frequency band. The circuit is designed to operate at a center frequency of 2.4 GHz while simultaneously eliminating the frequency band around 4.8 GHz, meeting key performance criteria including improved gain, better stability, and significant noise reduction. To achieve these objectives, the transistor used undergoes precise biasing via a DC power supply. In this process, a specifically selected capacitor is arranged in series with a λ/4 transformer. This transformer, in turn, is connected in series to a radial line section. The dimensions of the proposed amplifier are 70 × 34 mm2.For validation purposes, the proposed method was implemented through design, manufacture, and testing. The results obtained show that the proposed low noise amplifier achieves a high gain of 15.27 dB, an input reflection loss S11 of −16.26 dB, an output reflection loss S22 of −13.94 dB, and an inverse isolation S12 of −22.82 dB at 2.4 GHz, with a resonance peak at 4.8 GHz allowing the surrounding frequency band to be eliminated with an attenuation of 77 dB at 4.8 GHz. What's more, the noise figure is kept below 2 dB, with unconditional stability in the desired frequency band.

The Influence of the Assembly Line Configuration and Reliability Parameter Symmetry on the Key Performance Indicators

In the context of the demand for mass customization of products, a trade-off between highly efficient automated systems and flexible manual operators is sought. The linear arrangement of workstations made it possible to divide the process into many simple operations, which increases production efficiency, but also results in an increase in the number of workstations and a significant extension of the line. A human operator is usually treated as a quasi-mechanical object, and a human error is considered, similarly, as a failure of a technical component. However, human behavior is more complex and difficult to predict. A mathematical model of a new production organization is presented, including dividing the traditional production line into shorter sections or replacing the serial assembly line with a U-line with cells. Moreover, the reliability of operator and technical means are distinguished. Work-in-progress inventories are located between line sections to improve system stability. The stability of the assembly line is examined based on the system configuration and probabilistic estimates of human failure. The influence of the symmetry of reliability parameters of people on key performance indicators (KPI (headcount), KPI (surface) and KPI (Overall Equipment Effectiveness) is examined. KPI (solution robustness) and KPI (quality robustness) are also presented in order to evaluate the impact of a disruption on the assembly line performance. New rules for assigning tasks to stations are proposed, taking into account the risk of disruptions in the execution of tasks. For comparison of assembly problems, heuristic methods with newly developed criteria are used. The results show the impact of symmetry/asymmetry on assembly line performance and an asymmetric distribution of manual assembly times that is significantly skewed to the right due to human errors. On the assembly line, the effects of these errors are cumulative and lead to longer assembly times and lower KPIs.