alexandria engineering journal最新文献

{"title":"FLSecure: A hybrid framework with blockchain and multi-TEE parallel execution for secure federated learnings","authors":"Bian Zhu ,&nbsp;Ling Niu ,&nbsp;Yugui Zhang","doi":"10.1016/j.aej.2025.03.034","DOIUrl":"10.1016/j.aej.2025.03.034","url":null,"abstract":"<div><div>Federated Learning (FL) enables decentralized model training on private data but faces challenges such as single points of failure, adversarial attacks, and limited scalability. While blockchain-based FL frameworks address some of these issues by decentralizing model aggregation, they often suffer from computational inefficiencies and insufficient confidentiality during model updates. This paper presents FLSecure, a hybrid framework that integrates blockchain and Trusted Execution Environments (TEEs) to improve the privacy, security, and scalability of FL systems. By utilizing TEEs, FLSecure ensures secure aggregation of local model updates within isolated hardware environments, preventing unauthorized access and ensuring data integrity. Blockchain provides decentralized consensus and a tamper-proof audit trail, removing the dependency on centralized servers and enhancing transparency. FLSecure introduces a multi-TEE parallel execution strategy, which partitions global aggregation tasks into subtasks and distributes them across multiple TEEs for concurrent execution. This strategy mitigates TEE memory constraints and blockchain transaction bottlenecks, thereby enhancing scalability, reducing computational overhead, and supporting large-scale deployments. Experimental results demonstrate that FLSecure outperforms existing privacy-preserving FL frameworks in computational efficiency and overhead reduction. Furthermore, it exhibits robust resilience against adversarial threats, including backdoor and Byzantine attacks, offering a comprehensive solution to the security and scalability challenges in federated learning.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 300-317"},"PeriodicalIF":6.2,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field procedure and data collection tool: Towards controlling GPS multipath error for mapping within urban semi-closed areas","authors":"Mohamed M. Hosny ,&nbsp;Hassan G.Z. Elghazouly ,&nbsp;Samy Ayaad","doi":"10.1016/j.aej.2025.03.002","DOIUrl":"10.1016/j.aej.2025.03.002","url":null,"abstract":"<div><div>Multipath error, a significant challenge in GNSS positioning, arises from signals reaching the receiver via multiple paths, thus biasing range and location. This paper presents a new tool and charting method, using a predefined model, to mitigate multipath effects in pseudorange measurements within U-shaped urban obstructions. The model incorporates obstruction dimensions and receiver location, utilizing L1 and L2 carrier frequencies. Focusing on pseudorange errors caused by multipath at obstruction distances of 7–52 m, the study determines optimal observation times for various satellite systems and signal combinations. Charts are provided to determine the optimum observation time for the maximum required attainable accuracy, obstruction ratios (D/H), and angles (α). Results showed that total error decreased with longer observation times (10–120 minutes), ranging from 2 mm to 18.1 cm. Higher D/H ratios (closer obstructions) correlated with larger errors. Smaller obstruction angles generally yielded smaller errors, especially with longer observation times. The study produced a new charting tool to determine optimal observation time based on desired accuracy, D/H ratio, and α, aiming to minimize multipath error in obstructed environments. This tool aids in selecting optimal GPS antenna placement, measurement time, and expected accuracy in environments where reflection coefficients are difficult to determine.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 288-299"},"PeriodicalIF":6.2,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accuracy assessment of the 2D laminar boundary layer on a flat plate in an immersed boundary-Fourier pseudospectral simulations","authors":"Thiago Fernando Santiago de Freitas ,&nbsp;Aristeu da Silveira Neto ,&nbsp;Felipe Pamplona Mariano","doi":"10.1016/j.aej.2025.02.110","DOIUrl":"10.1016/j.aej.2025.02.110","url":null,"abstract":"<div><div>We investigate the accuracy of the laminar boundary layer on a flat plate by an immersed boundary — Fourier pseudospectral methods denominated as (IMERSPEC). The IMERSPEC solves the continuity equation and linear momentum equations numerically implementing the Pseudospectral Fourier Method (PFM) with the Fast Fourier Transform (FFT) algorithm. The reduced computational cost is achieved by the use of FFT as well as the pseudospectral approach which does not solve the convolution product of the advective term. Furthermore, the mathematical process of pressure projection replaces the solution of Poisson Equation while simultaneously ensures mass balance and decouples the pressure from the computational solution. The simulations of the laminar boundary layer at the Reynolds number of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> are performed using IMERSPEC and modelling the behaviour of the flow after the flat plate’s leading edge. To obtain reasonably accurate results such that the maximum error from the friction coefficient distribution obtained is less than 4% over the useful domain we use at least a uniform mesh with 1024 × 256 collocation points. The rightness showed in these results indicates far improvement from the usual finite volume method’s modelling which needs a local refinement mesh with far more volumes to present comparable results.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 279-287"},"PeriodicalIF":6.2,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An interpretable machine learning model for optimization of prediction index gases in coal spontaneous combustion","authors":"Jiuling Zhang ,&nbsp;Xu Zhou ,&nbsp;Jinpeng Su ,&nbsp;Yilong Xiao","doi":"10.1016/j.aej.2025.02.104","DOIUrl":"10.1016/j.aej.2025.02.104","url":null,"abstract":"<div><div>Early warnings of coal spontaneous combustion (CSC) have become urgent problems for coal enterprises. Existing approaches are designed to enhance the accuracy of CSC prediction. Improving the interpretability of the model is another important issue besides improving the prediction accuracy. Therefore, an interpretable machine learning framework based on RF (Random Forest) and SHAP (SHapley Additive exPlanations) is proposed to optimize prediction index gases. The data obtained from temperature-programmed experiments using coal samples from #5, #7, #8, #9, and #12 coal seams in Fangezhuang Mine are implemented to verify the proposed framework. <em>CO</em>, <em>O</em>_<em>2</em><em>/CO</em>, <em>CO/CO</em>_<em>2</em>, <em>CO/O</em>_<em>2</em>, <span><math><mrow><mi>C</mi><mi>O</mi><mo>/</mo><mi>Δ</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><mi>Δ</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><mi>Δ</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><mi>Δ</mi><mi>C</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>6</mn></mrow></msub><mo>/</mo><mi>C</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <em>C</em>_<em>2</em><em>H</em>_<em>4</em>, <em>CO</em>_<em>2</em><em>/O</em>_<em>2</em> are selected, which is explained the rationality of the selected indicators using SHAP, practical experience, and related theories. Comparison of results using different machine learning models and different parameter optimization approaches showed the accuracy of the model affects the interpretation of the results. Finally, through the ablation experiment, the R² of RF, XGBoost, and Linear Regression model before feature removal was 0.98, 0.95 and 0.9, the model accuracy decreased significantly after the deletion, which showed the optimal prediction performance of RF, and the importance and validity of the selected indicators were verified using SHAP interpretation.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 268-278"},"PeriodicalIF":6.2,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modified five-level LLC resonant inverter for multiple PV string systems","authors":"Ali Bughneda ,&nbsp;Mohamed Salem ,&nbsp;Mahmood Swadi ,&nbsp;Natarajan Prabaharan ,&nbsp;Eklas Hossain ,&nbsp;Dahaman Ishak ,&nbsp;Faisal A. Mohamed","doi":"10.1016/j.aej.2025.02.096","DOIUrl":"10.1016/j.aej.2025.02.096","url":null,"abstract":"<div><div>A modified multilevel LLC resonant inverter for multi-string photovoltaic (PV) applications. An efficient variable frequency and an integrated control method for the modulation index is proposed. To obtain the best efficiency, a steady output voltage gain, “ZVS, and a wide range of load variation, the designed LLC tank has been developed to run with a frequency range close to or at a resonant frequency. All the selected parameters for the analysis were emphasized in detail. Furthermore, the behaviour of the developed converter was investigated under varying load conditions at nominal input voltage, and under conditions of varying solar insolation and at full load. It was found that the control system responded to both changes successfully and maintained the value of the output voltage at its expected level by varying the switching frequency within a selected range, and produced <span><math><mrow><mn>1000</mn><mi>V</mi></mrow></math></span>,<span><math><mrow><mspace></mspace><mn>5</mn><mi>kW</mi></mrow></math></span> with <span><math><mrow><mn>97.6</mn><mo>%</mo></mrow></math></span> efficiency. Also, the developed five-level converter differed in LLC resonant behaviour compared to its typical behaviour with conventional full/half-bridge converters, as the LLC RC operated below resonant frequency under all load and input conditions. The theoretical results were validated experimentally using a lab prototype and through simulation using MATLAB-SIMULINK. Selected findings were discussed to portray the efficacy of the designed converter.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 215-228"},"PeriodicalIF":6.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated optimal parking slot prediction using deep learning and digital twin technology aided parking space management for material science application","authors":"Ke Lu ,&nbsp;Bei Zheng ,&nbsp;Jingjing Shi ,&nbsp;Yaowen Xu","doi":"10.1016/j.aej.2025.03.019","DOIUrl":"10.1016/j.aej.2025.03.019","url":null,"abstract":"<div><div>As vehicles on the roadside increase exponentially, drivers find it complicated to recognize parking areas. This makes it essential to identify an optimized model for resolving the vehicle-parking issues. In other words, a practical model must be implemented to identify outdoor parking slot status using sensing material or vehicles. For this purpose, the proposed technique aims at presenting an automated optimal parking slot detection and management using Active Learning (AL) and deep learning-based prediction model. The input images are retrieved from the input image dataset (PkLot). Then, the preprocessing stage is carried out by resizing, image enhancement, background subtraction, Hough transform, and a mixture of Gaussians. Improved Pre-trained U-Net-based feature extraction is carried out. The optimal features are selected using the Modified chaotic BAT optimization approach. The classification is finally done using Deep Cascaded Fine-tuned Active Learning and Inception V3 technique. The results are contrasted with the suggested approach and existing methods. The detected result is stored in the server regarding the real-time availability of slots. Then, digital twin technology manages parking space management to ensure slot availability. The assessment of performance is evaluated for varied metrics like mean accuracy, sensitivity, specificity, F1-score, recall, precision, FNR, and FPR and outcomes are compared with existing methodologies to validate the efficacy of proposed model.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 229-242"},"PeriodicalIF":6.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of thermal transfer in Casson hybrid nanofluids with magnetohydrodynamics and activation energy effects","authors":"Adnan Ashique ,&nbsp;Usman Afzal ,&nbsp;Sohaib Abdal ,&nbsp;Saif Ullah ,&nbsp;Nehad Ali Shah ,&nbsp;Jae Dong Chung","doi":"10.1016/j.aej.2025.02.067","DOIUrl":"10.1016/j.aej.2025.02.067","url":null,"abstract":"<div><div>Enhanced heat transfer is still a major challenge in many engineering industries in the modern era including advanced cooling systems and material processing techniques. There have been past researches in the effects of magnetohydrodynamics (MHD), Casson fluids and nanofluid flows, however, there is not much that has been done to investigate the combined effects of these factors in a hybrid nanofluid system while incorporating activation energy, Hall effect and current parameters. Through investigating the inextricable connections between these parameters, the current study introduces a novel approach by employing unified model regarding the aforementioned hybrid Casson nanofluid flow over a stretching sheet. The methodology used in the research consists of transforming the non-linear higher order partial differential equations which represent the fluid behavior into first order linear ordinary differential equations through similarity transformation and using the Runge Kutta 4th order method in conjunction with the shooting technique for numerical analysis. This points out the special role of magnetic and Casson parameters in tangential velocity and reveals the effect of the Hall and current effect on the velocity and temperature profiles. The study also shows the potential of hybrid nanofluids in enhancing the performance of thermal management systems. Besides supplementing an important gap in the current literature, this research provides unique insights to potentially propel innovations in industrial contexts where efficient heat transfer and fluid flow are essential.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 255-267"},"PeriodicalIF":6.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impulsive noise estimation for underwater acoustic OFDM communication using signal-noise separation and distributed compressed sensing methods","authors":"Xiaoyu Yang,&nbsp;Yuehai Zhou,&nbsp;Junhui Yao,&nbsp;Feng Tong","doi":"10.1016/j.aej.2025.02.087","DOIUrl":"10.1016/j.aej.2025.02.087","url":null,"abstract":"<div><div>In underwater acoustic (UWA) orthogonal frequency division multiplexing systems, impulsive noise and carrier frequency offsets (CFOs) may contaminate subcarriers. Traditionally, CFOs and impulsive noise are estimated using null subcarriers, reducing spectral efficiency. This article proposes a signal-noise separation based and distributed compressed sensing based method to jointly estimate impulsive noise, channels, and CFOs using only pilot subcarriers, thereby significantly improving spectral efficiency. Specifically, the signal-noise separation method segregates channel and impulsive noise portions in a specific orthogonal subspace, preventing error propagation. To further facilitate impulsive noise estimation and reduce the required number of pilot subcarriers, the distributed compressed sensing method is utilized based on the significant sparse correlation of impulsive noise. Additionally, an adaptive sparsity detection algorithm for measuring the sparsity of impulsive noise is introduced. The effectiveness of the proposed methods is comprehensively validated through simulation experiments demonstrating improvements in impulsive noise estimation, channel estimation, and output signal-to-noise ratio (SNR), with gains of at least 26.30 dB, 22.91 dB, and 11.05 dB, respectively, compared to existing algorithms. Moreover, sea trial experiments indicate an average output SNR gain exceeding 3.10 dB. The superior systems with higher data rates and more robustness significantly accelerate the development of UWA communication.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 243-254"},"PeriodicalIF":6.2,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined timetabling of periodic and aperiodic trains using an efficient train-based Lagrangian relaxation decomposition","authors":"Naijie Chai ,&nbsp;Wenliang Zhou ,&nbsp;Ziyu Chen ,&nbsp;Qipeng Sun","doi":"10.1016/j.aej.2025.03.003","DOIUrl":"10.1016/j.aej.2025.03.003","url":null,"abstract":"<div><div>To better meet passenger travel demands and meanwhile improve regularity and flexibility of train operation, this study focuses on solving the optimization problem of periodic and aperiodic train timetabling, and establishes an integer linear programming model with many binary variables and non-negative integer variables. This model systematically considers the constraints of equal-interval operation of periodic trains, dwell times, arrival and departure safety time intervals, no overtaking requirements in the section and so on. Due to the NP-hard property of the established model, a space-time discretized network is constructed to reformulate and transform the periodic and aperiodic train timetabling problem into two types of shortest path-choice problems related to periodic and aperiodic trains, respectively. And an efficient train-based Lagrangian relaxation decomposition algorithm is designed to solve the reformulated model. Finally, the feasibilities of the proposed model and algorithm are verified by a set of numerical experiments, involving a small-scale case and a real-world case derived from Beijing-Shanghai high-speed railway.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 28-56"},"PeriodicalIF":6.2,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solitary wave solution in a perturbed simplified modified Camassa–Holm equation","authors":"Cui-Hua Jin ,&nbsp;Yong-Hui Xia ,&nbsp;Hang Zheng","doi":"10.1016/j.aej.2025.02.038","DOIUrl":"10.1016/j.aej.2025.02.038","url":null,"abstract":"<div><div>This paper investigates the persistence of solitary wave solution in a perturbed simplified modified Camassa–Holm equation. The perturbation terms are the backward diffusion and dissipation, which come from the Kuramoto–Sivashinsky equation. Firstly, on the basis of the classical Camassa–Holm equation, the bifurcated phase portraits of homoclinic orbit (or cuspidal loop) and solitary wave solution for unperturbed simplified modified Camassa–Holm equation are obtained by dynamic system method. And the persistence of solitary wave solutions with suitable wave speed <span><math><mi>c</mi></math></span> under Kuramoto–Sivashinsky perturbation is proved by using the geometric singular perturbation approach and Melnikov integral. Different from the study of the cuspidal loop in previous work, the simple zero point of Melnikov integral is obtained by calculating its explicit expression. At last, the results are verified by numerical simulation.</div></div>","PeriodicalId":7484,"journal":{"name":"alexandria engineering journal","volume":"122 ","pages":"Pages 91-97"},"PeriodicalIF":6.2,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143600917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}