Simulated Peak Research Articles

Floods modeling and analysis for Dubai using HEC-HMS model and remote sensing using GIS

Floods accompanied by thunderstorms in developed cities are hazardous, causing damage to infrastructure. To secure infrastructure, it is important to employ an integrated approach, combining remote sensing, GIS and precipitation data. The model was developed based on the estimation of event-based runoff and investigated the relationship between runoff and impervious surfaces. The novel approach of combining Hydrologic Engineering Center’s River Analysis System (HEC-GeoRAS) along with satellite imagery was utilized, where spatial data was combined with real-time values to run the model. As a first step, the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model was fed with information about precipitation, slope, soil type, as well as land use and land cover. The results reveal that the subbasins of Deira, Nief and Jumeirah have the largest impervious area and, thus, a higher probability of flood occurrence. The model was calibrated and validated using previous runoff events and by comparing observed and simulated streak flow and peak discharge against those reported in previous studies. It was found that the model is efficient and can be used in similar regions.

Simulation of Friction Stir Welding of AZ31 Mg Alloys.

Friction stir welding has been extensively applied for the high-quality bonding of Mg alloys. The welding temperature caused by friction and plastic deformation is essential for determining the joint characteristics, especially the residual stress and weld microstructure. In this work, a modified moving heat source model was proposed by considering the variations in heat generation caused by friction shear stress at both the side and bottom surfaces of the tool. The application of this model was further extended to the entire welding process, especially in the plunging stage. The relative errors between the experimental and simulated peak temperatures at characteristic points were small, with a maximum of 10%, thereby validating the model for accurate temperature prediction. Furthermore, the influence of welding and rotational speed on temperature fields was systematically investigated. At relatively low welding and rotational speeds, the welding temperature increased significantly with either an increase in rotational speed or a decrease in welding speed. However, this effect gradually diminished at higher welding and rotational speeds. These results provide some valuable guidelines for controlling heat generation to improve the quality of Mg alloy welds.

B-Doped Graphdiynes and Several of Their Corresponding Oxides: A Theoretical Study by X-ray Spectra.

Boron doping can significantly improve the electronic structure and physical and chemical properties of graphdiyne (GDY), which also expands its application prospects in photoelectricity, catalysis, and biology. The accurate configurations characterization of B-doped graphdiyne (B-GDY) has not been achieved due to insufficient experimental and theoretical research. The current work involves the simulation of the geometries of 11 typical B-GDY and B-doped graphdiyne oxides [B(O)-GDY] as well as a pristine GDY, along with their X-ray photoelectron (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectra at the density functional theory (DFT) level. The boron and carbon spectra for various bonding types were theoretically imitated to assess the spectral contributions. Calculated outcomes indicate that there is a noticeable dependence of the NEXAFS spectra on the local structure. The simulated XPS spectra provide precise assignments and an extra supplement to the spectra peaks, in addition to the position and general peak forms of simulated spectral peaks matching the experimental spectra fairly well. The combination of XPS and NEXAFS spectra can give useful information for identifying typical B-GDY and B(O)-GDY molecules. This paper offers a comprehensive structure-spectrum relationship of B-GDY and its oxides as well as a further theoretical prediction and guidance for experimental synthesis, which is helpful to solve the challenging issue of identification of B-doped carbon-based materials.

Internal Electrostatic Discharge Modeling: Validation and Fitting Using Tests on Insulated Wires

Electron beam tests were conducted to observe the internal electrostatic discharge behavior of four wire samples arcing into three termination resistors. The charging environment during the test was also simulated using 3-D NUMIT to calculate the expected voltage development within each wire. The impedances of the wires and the test setup were measured and included in a circuit model of the discharging wire connected to the measurement circuit. The circuit model was fit to the largest discharge observed on a 50 Ω load. The circuit model was then used to simulate discharges into 5 kΩ and 10 MΩ terminations, and the simulated pulses were compared to observed pulses on those terminations. Simulated peak voltages agree with observed voltages to within a factor of 1.6 and simulated decay times agree with observed decay times to within a factor of 2.3. For large pulses, derived source voltages range from 3.7 to 15.5 kV, derived source capacitances range from 4 to 11 pF, and derived source resistances range from 1100 to 3500 Ω.

On the Realism of Tropical Cyclone Intensification in Global Storm‐Resolving Climate Models

AbstractThe physical processes governing a tropical cyclone's lifecycle are largely understood, but key processes occur at scales below those resolved by global climate models. Increased resolution may help simulate realistic tropical cyclone intensification. We examined fully coupled, global storm‐resolving models run at resolutions in the range 28–2.8 km in the atmosphere and 28–5 km in the ocean. Simulated tropical cyclone activity, peak intensity, intensification rate, and horizontal wind structure are all more realistic at a resolution of ∼5 km compared with coarser resolutions. Rapid intensification, which is absent at typical climate model resolutions, is also captured, and exhibits sensitivity to how, and if, deep convection is parameterized. Additionally, the observed decrease in inner‐core horizontal size with increasing intensification rate is captured at storm‐resolving resolution. These findings highlight the importance of global storm‐resolving models for quantifying risk and understanding the role of intense tropical cyclones in the climate system.

Testing the Feasibility of an Agent-Based Model for Hydrologic Flow Simulation

Modeling streamflow is essential for understanding flow inundation. Traditionally, this involves hydrologic and numerical models. This research introduces a framework using agent-based modeling (ABM) combined with data-driven modeling (DDM) and Artificial Intelligence (AI). An agent-driven model simulates streamflow and its interactions with river courses and surroundings, considering hydrologic phenomena related to precipitation, water level, and discharge as well as channel and basin characteristics causing increased water levels in the Medio River. A five-year dataset of hourly precipitation, water level, and discharge measurements was used to simulate streamflow. The model’s accuracy was evaluated using statistical metrics like correlation coefficient (r), coefficient of determination (R2), root mean squared error (RMSE), and percentage error in peak discharge (Qpk). The ABM’s simulated peak discharge (Qpk) was compared with the measured peak discharge across four experimental scenarios. The best simulations occurred in scenario 3, using only rainfall and streamflow data. Data management and visualization facilitated input, output, and analysis. This study’s ABM combined with DDM and AI offers a novel approach for simulating streamflow and predicting floods. Future studies could extend this framework to other river basins and incorporate advanced sensor data to enhance the accuracy and responsiveness of flood forecasting.

Deconvoluting XPS Spectra of La-Containing Perovskites from First-Principles.

Perovskite-based oxides are used in electrochemical CO2 and H2O reduction in electrochemical cells due to their compositional versatility, redox properties, and stability. However, limited knowledge exists on the mechanisms driving these processes. Toward this understanding, herein we probe the core level binding energy shifts of water-derived adspecies (H, O, OH, H2O) as well as the adsorption of CO2 on LaCoO3 and LaNiO3 and correlate the simulated peaks with experimental temperature-programmed X-ray photoelectron spectroscopy (TPXPS) results. We find that the strong adsorption of such chemical species can affect the antiferromagnetic ordering of LaNiO3. The adsorption of such adspecies is further quantified through Bader and differential charge analyses. We find that the higher O 1s core level binding energy peak for both LaCoO3 and LaNiO3 corresponds to adsorption of water-related species and CO2, while the lower energy peak is due to lattice oxygen. We further correlate these density functional theory-based core level O 1s binding energies with the TPXPS measurements to quantify the decrease of the O 1s contribution due to desorption of adsorbates and the apparent increase of the lattice oxygen (both bulk and surface) with temperature. Finally, we quantify the influence of adsorbates on the La 4d, Co 2p, and the Ni 3p core level binding energy shifts. This work demonstrates how theoretically generated XPS data can be utilized to predict species-specific binding energy shifts to assist in deconvolution of the experimental results.

Modelación de mapa de inundaciones durante el Huracán Alex: simulación usando precipitación multisensorial en la ciudad de Monterrey, México

Alex Hurricane was one of the most intense tropical cyclones in the North Atlantic, that caused fatalities and loses in the Northeast of Mexico due to the flash floods. Flood hazard mapping is a vital tool to assess inundation areas, which can be simulated using hydraulic and hydrologic models. This study describes the modelling of a flood event during Alex Hurricane in the Santa Catarina River Watershed, Northeast of Mexico, applying HEC-HMS and two dimensional (2D) HEC-RAS models forced with Multi Radar Multi Sensor - Quantitative Precipitation Estimation (MRMS-QPE). A HEC-HMS model was developed forced by (MRMS-QPE) as input to simulate discharges along the Santa Catarina River. The simulated discharges were introduced as border conditions along the mainstream of the Santa Catarina River inside a HEC-RAS 2D model to simulate a flood map along the mainstream of the Santa Catrina River. The observed against the simulated peak discharges achieved a R-squared of 0.97 and a Nash - Sutcliffe coefficient of 0.97. The observed against the simulated accumulated discharges achieved a R-squared of 0.99 and a Nash - Sutcliffe coefficient of 1.0. The observed against the simulated stages achieved a R-squared of 0.74 and, a Nash - Sutcliffe coefficient of 0.68. The use of HEC-HMS and HEC-RAS 2D models coupled with MRMS-QPE. shows that these models are user friendly to setup, the model has stability and the capacity to simulate flood maps along the whole mainstream of the Santa Catarina River with good results.

A Miniaturized Dual-Band Circularly Polarized Implantable Antenna for Use in Hemodialysis.

Hemodialysis is achieved by implanting a smart arteriovenous graft (AVG) to build a vascular pathway, but reliability and stability in data transmission cannot be guaranteed. To address this issue, a miniaturized dual-band circularly polarized implantable antenna operating at 1.4 GHz (for energy transmission) and 2.45 GHz (for wireless telemetry), implanted in a wireless arteriovenous graft monitoring device (WAGMD), has been designed. The antenna design incorporates a rectangular serpentine structure on the radiation surface to reduce its volume to 9.144 mm3. Furthermore, matching rectangular slots on the radiation surface and the ground plane enhance the antenna's circular polarization performance. The simulated effective 3 dB axial ratio (AR) bandwidths are 11.43% (1.4 GHz) and 12.65% (2.45 GHz). The simulated peak gains of the antenna are -19.55 dBi and -22.85 dBi at 1.4 GHz and 2.45 GHz, respectively. The designed antenna is implanted in a WAGMD both in the simulation and the experiment. The performance of the system is simulated in homogeneous human tissue models of skin, fat, and muscle layers, as well as a realistic adult male forearm model. The measurement results in a minced pork environment align closely with the simulation results.

Evaluating Distributed Snow Model Resolution and Meteorology Parameterizations Against Streamflow Observations: Finer Is Not Always Better

AbstractEstimating snow conditions is often done using numerical snowpack evolution models at spatial resolutions of 500 m and greater; however, snow depth in complex terrain often varies on sub‐meter scales. This study investigated how the spatial distribution of simulated snow conditions varied across seven model spatial resolutions from 30 to 1,000 m and over two meteorological data sets, coarser (≈12 km) and finer (4 km). Simulated snow covered area (SCA) was compared to remotely sensed SCA and simulated watershed mean peak snow water equivalent (SWE) was compared to four streamflow statistics representing different water management‐relevant aspects of the hydrograph using non‐parametric correlations. April 1 SWE tended to increase with model resolution, particularly below 4,000 masl. Finer meteorology simulations produced deeper April 1 SWE than coarser meteorology simulations. Finer resolution snow simulations tended to produce longer snowmelt durations and slower snowmelt rates than coarser resolution simulations. Finer resolution simulations had better agreement with SCA for both meteorology data sets, particularly at high and low elevations. However, finer resolution simulations did not generally outperform coarser simulations in snow versus streamflow statistic correlations. Snow versus streamflow correlations were most sensitive to meteorology, watershed properties, and then resolution. Watershed physiographic properties such as wetness index may increase snow versus streamflow metric correlations while elevation and slope may decrease correlations. At watershed scales, these results suggest that simulation resolution and choice of meteorology is less important than the physiographic properties of the watershed; however, if resolving snow distribution across the landscape is important, finer‐resolution simulations are useful.

Evaluating Passive Housing Strategies in Extreme Climates: A Case Study of Dubai Using PHPP and IESVE Models

The increasing global emphasis on sustainable architecture necessitates precise building energy modeling, especially in regions marked by extreme climates. The focus of this study is to evaluate the potential and practicality of passive housing strategies in climates similar to Dubai. In this study, we employed the Passive House Planning Package (PHPP) to create a meticulous representation of the Dubai environmental conditions, ensuring that detailed architectural elements and HVAC systems were captured to provide the most energy-efficient architecture. To validate the accuracy of the model, consumption data from 2020 was used as a benchmark, reflecting the observed hot water and electricity consumption. Additionally, we developed a linear state-space model using IES Virtual Environment software (IESVE) to capture the dynamic thermal behaviour of the proposed building. We assessed the merits of the Passivhaus model in harsh climates and compared them with those of various space calculation methodologies. The model showed significant congruence with the actual consumption data and external temperature metrics for 2020. Furthermore, the state-space model, along with its various state variables, inputs, and outputs, aligned well with the real-world observations. The results indicate that the Passivhaus model possesses significant potential to reduce carbon emissions, highlighted by a detected 10% variance in energy consumption during the simulated summer peak. Differences in space calculation methodologies were also determined, emphasising the necessity of context-driven architectural evaluation. This study provides invaluable insights into the energy dynamics of contemporary buildings and emphasises the transformative potential of passive housing in extreme climates.

A dynamic response prediction of ultra-high strain rates of composite materials based on a surrogate model

Based on the propagation of laser-induced tensile waves in materials and the principle of material ply cracking, nondestructive testing technology for measuring the interfacial bonding force of composite materials can be developed. The study of the ultra-high strain rate dynamic response model of composite materials under the action of laser shock waves is crucial to this technique. Therefore, this paper proposes a method for constructing a dynamic response prediction model for composites based on data and a physical model driven by comprehensively considering the strain rate effect of materials. The constructed model can accurately predict the peak velocity and duration of the initial pulse of the velocity curve under the condition of ultra-high strain rate. The relative error between the predicted and simulated peak values is within 3%, and the relative error between the predicted and simulated initial pulse durations is within 5%. In addition, laser impact experiments were conducted on specimens of various thicknesses to validate the accuracy of the predicted data at ultra-high strain rates. The results show that the relative errors between the predicted and experimental peak values are all within 2%, and the relative errors of the initial pulse duration are within 9%.

Rainfall-Runoff Simulation for Ungauged Watershed: A Case of Bessre Watershed, Duhok Province, Iraq

The scarcity of measured hydrological data poses a challenge in many developing countries, stemming from insufficiently established gauging stations. Due to the mentioned issue, it is crucial to develop models capable of conducting reliable simulations of runoff behavior, particularly for ungauged catchments. Understanding the intricate relationships in rainfall-runoff modeling is essential for estimating peak flows, a critical aspect in formulating water resources management strategies, which can aid in water resource management and planning. In areas prone to floods performing, an extensive hydrological study becomes necessary. This study determined the outflow discharge at the outlet point of the Bessre Valley Ungauged Catchment (41.4 km2) using the Watershed Modeling System, used by reliable hydrological standards as a graphical interface integrating with the Hydrologic Modeling System (HEC-HMS). Bessre Valley watershed is one of the flood-prone watersheds in the Duhok governorate, mainly due to the terrain’s steep slopes at the upper north and east of the catchment. The catchment was delineated by a Geographic Information System (GIS). Its properties were extracted from a 12.5 m × 12.5 m Digital Elevation Model (DEM), which evaluates the hydrological response of a watershed to two significant storm events: a real rainfall event in March 2020 and a hypothetical 100-year return period event by dividing the watershed into ten sub-basins. Achieving a Nash-Sutcliffe efficiency of 0.895 indicates a high accuracy between observed and simulated peak flows of the real rainfall event of March 2020, underscoring the model's reliability for hydrological predictions. Also, comparing the HEC-HMS model and the Rational Method of (100 YRP event) for calculating peak discharges revealed a mere 2.2% error. Furthermore, the study explores the potential for building additional dams based on discharge volumes from specific sub-basins to enhance flood control and water storage capabilities.

Curved carbon-plated shoe may further reduce forefoot loads compared to flat plate during running

Using a curved carbon-fiber plate (CFP) in running shoes may offer notable performance benefit over flat plates, yet there is a lack of research exploring the influence of CFP geometry on internal foot loading during running. The objective of this study was to investigate the effects of CFP mechanical characteristics on forefoot biomechanics in terms of plantar pressure, bone stress distribution, and contact force transmission during a simulated impact peak moment in forefoot strike running. We employed a finite element model of the foot-shoe system, wherein various CFP configurations, including three stiffnesses (stiff, stiffer, and stiffest) and two shapes (flat plate (FCFP) and curved plate (CCFP)), were integrated into the shoe sole. Comparing the shoes with no CFP (NCFP) to those with CFP, we consistently observed a reduction in peak forefoot plantar pressure with increasing CFP stiffness. This decrease in pressure was even more notable in a CCFP demonstrating a further reduction in peak pressure ranging from 5.51 to 12.62%, compared to FCFP models. Both FCFP and CCFP designs had a negligible impact on reducing the maximum stress experienced by the 2nd and 3rd metatarsals. However, they greatly influenced the stress distribution in other metatarsal bones. These CFP designs seem to optimize the load transfer pathway, enabling a more uniform force transmission by mainly reducing contact force on the medial columns (the first three rays, measuring 0.333 times body weight for FCFP and 0.335 for CCFP in stiffest condition, compared to 0.373 in NCFP). We concluded that employing a curved CFP in running shoes could be more beneficial from an injury prevention perspective by inducing less peak pressure under the metatarsal heads while not worsening their stress state compared to flat plates.

Micro-Spectrometer-Based Interferometric Spectroscopy and Environmental Sensing with Zinc Oxide Thin Film

This study introduces a novel approach for analyzing thin film interference spectra by employing a micro-spectrometer equipped with a spectral chip. Focusing on zinc oxide (ZnO) thin films prepared via the sol–gel method, this research aims to explore the films’ physical properties through spectral analysis. After obtaining the interference spectrum of the ZnO thin films, the peak positions within the spectrum were cataloged. Mathematical simulation was used to adjust the refractive index and thickness of the films to match the simulated interference peak positions with the observed peak positions. The thickness of the prepared ZnO film was estimated to be 4.9 μm and its refractive index at 80 °C was estimated to be 1.96. In addition, the measurement system was used to detect environmental changes, including temperature changes and gas exposure. It was observed that the optical characteristics of ZnO films exhibit marked variations with temperature shifts, enabling the establishment of a temperature calibration curve based on spectral feature displacement. In addition, experiments using a variety of gases showed that NO2 and gaseous isopropanol significantly affect the interference spectrum of ZnO, with the peak of the interference spectrum shifted by 2.3 nm and 5.2 nm, respectively, after injection of the two gases. This indicates that interferometric spectroscopy can serve as an effective tool for ZnO monitoring, capable of selectively detecting specific gases.

Comparative study of dynamic parameters for damage identification of carbon fiber reinforced polymer tube

AbstractThe primary objective of the paper is the numerical and experimental investigation related to the damage recognition effects for CFRP tubes of four dynamic parameters. Four damage identification indexes consisting of natural frequency‐based index, Mode Shape‐based index (MS), Mode Shape Curvature‐based index (MSC), and Modal Flexibility Curvature‐based index (MFC) are established by analyzing the dynamic parameter data obtained before and after damage occurs. The performances of dynamic parameters are thoroughly discussed in the context of numerical simulations and experiment. The results indicate that the effect of natural frequency is not as significant as that of mode shape. MFC has the most notable effectiveness out of the four indexes. The simulation peak index pair is predicted to rise from 0.3 to 0.6 as the damage in the simulation model increases by 25% from 12.5%, indicating that MFC can feedback the damage degree. Moreover, the circumferential curvature index exhibits superior performance compared to the axial curvature index. To enhance the accuracy of the axial curvature index, it is proposed to increase the number of measuring sites along the tube's long direction.Highlights Damage identification indexes of four dynamic parameters are established. Discuss the identification ability of dynamic parameters by simulation and test. Two numerical models of CFRP tube with delamination damage are established. Impact and modal tests are executed to study the ability of four indexes.

A Temporal Methodology for Assessing the Performance of Concatenated Codes in OFDM Systems for 4K-UHD Video Transmission

The communication channel is a critical part of the process of information degradation. In the 4K ultra-resolution video transmission domain, the communication channel is a crucial part where information degradation occurs, inevitably leading to errors during reception. To enhance the transmission process in terms of fidelity, advanced technologies such as digital video broadcasting terrestrial (DVB-T) and its evolutionary successor, digital video broadcasting terrestrial second generation (DVB-T2), are utilized to mitigate the effects of data transmission errors. Within this scenario, this research presents an innovative methodology for the temporal analysis of 4K ultra-resolution video quality under the influence of additive white Gaussian noise (AWGN) and Rayleigh channels. This analytical endeavor is facilitated through the application of concatenated coding schemes, specifically, the Bose–Chaudhuri–Hocquenghem concatenated low-density parity check (BCH-LDPC) and Reed–Solomon concatenated convolutional (RS-CONV) coders. A more comprehensive understanding of video quality can be attained by considering its temporal variations, a crucial aspect of the ongoing evolution of technological paradigms. In this study, the Structural Similarity Index (SSIM) serves as the main metric for quality assessment during simulations. Furthermore, the simulated Peak Signal-to-Noise Ratio (PSNR) values validate these findings, exhibiting consistent alignment with the SSIM-based evaluations. Additionally, the performance of the BCH-LDPC significantly outperforms that of RS-CONV under the 64-QAM modulation scheme, yielding superior video quality levels that approximate or surpass those achieved by RS-CONV under QPSK (Quadrature Phase Shift Keying) modulation, leading to an increase in spectral efficiency. This enhancement is evidenced by SSIM gains exceeding 78% on average. The computation of average gains between distinct technologies in video quality analysis furnishes a robust and comprehensive evaluation framework, empowering stakeholders to make informed decisions within this domain.

Selective phosphate removal by lanthanum carbonate @ anion exchange resin with fixed-bed column: RSM for process optimization and DFT for mechanistic study

Lanthanum carbonate @ anion exchange resin (LC@AER) has shown promise in adsorption processes due to its high maximum adsorption capacity and excellent stability in comparison with other lanthanum-based adsorbents. Nevertheless, there is a lack of significant investigation in evaluating the collective effect of the most influential parameters and determining the molecular complexes between the adsorbent and phosphate. This work aims to comprehensively evaluate and optimize the phosphate adsorption performance in fixed-bed columns and to determine the most favourable molecular configurations. Firstly, a response surface model (RSM) was developed to describe the phosphate adsorption performance in fixed-bed columns under the collective effect of selected independent variables, including influent pH, co-existing sulfate concentration, and empty bed contact time (EBCT). The RSM analysis reveals the significant effects of influent pH and co-existing sulfate concentration on phosphate adsorption. Moreover, the model achieves a correlation coefficient of >0.9, demonstrating its suitability for describing the experimental data. Secondly, various phosphate-lanthanum carbonate configurations were formulated, and the respective adsorption energies were compared using density functional theory (DFT) calculations. Subsequently, bidentate mononuclear complexes are determined as the most favourable configurations. The successful matching of the simulated peak locations with the experimental deconvoluted spectra further confirms the presence of such complexes in the system. Overall, this work provides an improved foundation and underlayer theory for potential future scale-up work on phosphate adsorption over LC@AER.

Univariate versus multivariate flood frequency analysis in tropical region: Employing two classes of hydrological models

AbstractFlood frequency analysis is critical in flood planning and management and hydraulic structures design. While univariate flood frequency analysis (using the peak flow) is still widely employed in developing countries, how does it compare to the robust copula‐based bivariate flood frequency analysis remains unknown. Moreover, there is also a decade‐long critical question whether less data requiring hydrological models can be an alternate to the data‐intensive models in flood prediction, especially in a developing tropical country like India? To answer these questions, this study aims in comparing two types of hydrological models (IHACRES, a less data requiring model, and VIC‐3L, a data‐intensive model) in simulating the peak flows, following which the simulated peak flows are used in a detailed comparison of the univariate and bivariate flood frequency analysis. The results indicate that the data‐intensive fully distributed hydrological model performs poorly relative to the conceptually lumped IHACRES model at the study catchment in simulating the peak flows. Moreover, both univariate and copula‐based bivariate flood frequency analyses show similar peak flows for a given return period at the study catchment. Given that bivariate flood frequency analysis accounts for both peak flow and flood volume, it is recommended over the univariate flood frequency analysis since the results are widely applicable for flood planning and hydraulic structure designing the developing countries.

Relationship of various COVID-19 antibody titer with individual characteristics and prediction of future epidemic trend in Xiamen City, China.

Reinfection of coronavirus disease 2019 (COVID-19) has raised concerns about how reliable immunity from infection and vaccination is. With mass testing for the virus halted, understanding the current prevalence of COVID-19 is crucial. This study investigated 1,191 public health workers at the Xiamen Center for Disease Control, focusing on changes in antibody titers and their relationship with individual characteristics. The study began by describing the epidemiological characteristics of the study participants. Multilinear regression (MLR) models were employed to explore the associations between individual attributes and antibody titers. Additionally, group-based trajectory models (GBTMs) were utilized to identify trajectories in antibody titer changes. To predict and simulate future epidemic trends and examine the correlation of antibody decay with epidemics, a high-dimensional transmission dynamics model was constructed. Analysis of epidemiological characteristics revealed significant differences in vaccination status between infected and non-infected groups (χ2=376.706, P<0.05). However, the distribution of antibody titers among the infected and vaccinated populations was not significantly different. The MLR model identified age as a common factor affecting titers of immunoglobulin G (IgG), immunoglobulin M (IgM), and neutralizing antibody (NAb), while other factors showed varying impacts. History of pulmonary disease and hospitalization influenced IgG titer, and factors such as gender, smoking, family history of pulmonary diseases, and hospitalization impacted NAb titers. Age was the sole determinant of IgM titers in this study. GBTM analysis indicated a "gradual decline type" trajectory for IgG (95.65%), while IgM and NAb titers remained stable over the study period. The high-dimensional transmission dynamics model predicted and simulated peak epidemic periods in Xiamen City, which correlated with IgG decay. Age-group-specific simulations revealed a higher incidence and infection rate among individuals aged 30-39 years during both the second and third peaks, followed by those aged 40-49, 50-59, 18-29, and 70-79 years. Our study shows that antibody titer could be influenced by age, previous pulmonary diseases as well as smoking. Furthermore, the decline in IgG titers is consistent with epidemic trends. These findings emphasize the need for further exploration of these factors and the development of optimized self-protection countermeasures against reinfection.