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A robust and efficient multi-port converter design for electric vehicle applications: optimized via artificial gorilla troops algorithm

Research Abstract

This paper presents a multiport converter (MPC) designed for electric vehicle (EV) applications, with
potential use in renewable energy systems (RES). The proposed MPC interfaces the AC grid, enabling
seamless energy transfer from input sources to multiple output ports. These output ports facilitate the
simultaneous management of two distinct voltage levels through a single DC link, enhancing system
flexibility and efficiency. The Control scheme, employing Proportional-Resonant (PR) and Propor-
tional-Integral (PI) controllers, is implemented to regulate power flow between input sources and
loads. The system operates in three modes: Mode 1 employs power factor correction (PFC) to
synchronize voltage and current while reducing harmonics, the Total Harmonic Distortion (THD) of
the grid current is 3.65%; Mode 2 allows grid-to-battery charging while supplying a low-voltage load;
and Mode 3 functions as a single-input dual-output converter to power both the motor and auxiliary
loads. Additionally, Artificial Gorilla Troops Optimizer (AGTO) is used to rapidly and precisely tune
controller parameters. The proposed MPC features a modular structure and achieves a high efficiency
of 98.64%, surpassing the reported efficiencies in previous studies, while consisting of 12 components
only, making it a promising solution for sustainable energy management in EVs and RES applications.

Research Authors
Alaa A Mahmoud, Mahmoud Aymen Ahmed, and Ahmed A Hafez
Research Date
Research Department
Research Member
Research Year
2025

A Model for Mitigating Causes of Waste Effect Using Lean Management Techniques in Green Building Projects

Research Abstract
Lean construction is considered a new methodology for minimizing the causes of waste that hinder the achievement of green building (GB) goals. The main aim of this study is to develop a lean model using fuzzy logic technique to mitigate causes of waste effect in GB projects and to determine the most appropriate lean tools affecting these causes. The inputs of this model include GB waste and four lean tools, comprising Quality Function Deployment (QFD), Last Planner System (LPS), Value Stream Mapping (VSM), and 5S, while the outputs include four improvement level indices based on the lean tools. The model uses various logical rules to achieve several relations among the inputs and outputs, and it is applied and verified using data related to several causes of waste categorized under five groups. The strongest correlation is found between VSM and 5S indices, while an adverse relationship is observed between QFD and 5S indices. The results indicate that a cause of waste that refers to poor assessment of site conditions is considered the most substantial one due to its high improvement level indices across all lean tools. The most significant waste group is related to GB stakeholders, which contains 38% of key causes of waste. The improvement using QFD increases by 10% compared to VSM and 28.20% compared to 5S. QFD and LPS are measured as the most suitable lean tools to mitigate the causes of waste effects due to their high impact and high improvement level indices.
Research Authors
Ahmed Gamal AbdelHaffez, Usama Hamed Issa, Alaa Atif Abdel-Hafez, and Kamal Abbas Assaf
Research Date
Research Department
Research Journal
Buildings
Research Pages
3538
Research Publisher
MDPI
Research Rank
Q1
Research Vol
15
Research Website
https://doi.org/10.3390/buildings15193538
Research Year
2025

Identifying and evaluating causes of waste effect in green building projects

Research Abstract

Green building (GB) projects in the Middle East face several causes of waste that occur during design and construction stages. These causes affect the objectives of GB projects (economic, environmental, and social). Therefore, this research aims to define causes of waste in GB projects and evaluate the effect of these causes on the objectives of GB projects. Forty-five causes of waste are determined and classified into five main groups as follows: (G01) green materials, (G02) green building design, (G03) sustainable site, (G04) green building technologies, and (G05) green building stakeholders. Through field surveys, including semi-structured interviews and brainstorming sessions, the probability of occurrence for each cause of waste and impact on the economic, environmental, and social objectives are evaluated, as well as the waste severity is determined based on a combined effect of probability and impacts. The correlations among the waste indices are assessed, and the highest correlation is observed between probability and economic followed by economic and social objective. The results show that the most significant cause of waste that has the highest value for economic, environmental, and social objectives is “Poor assessment of site conditions before design, such as topography, hydrology, climate, vegetation, and soil.” Group 05 has the maximum number of critical causes of waste, which is considered the most significant group, due to its high values related to all objectives. Results indicate that the economic objective is classified as the most affected one by the causes of waste, followed by the environmental objective.

Research Authors
Usama Hamed Issa, Ahmed Gamal AbdelHaffez, Alaa Atif Abdel-Hafez, and Kamal Abbas Assaf
Research Date
Research Department
Research Journal
Journal of Engineering and Applied Science
Research Pages
25
Research Publisher
Springer Nature
Research Vol
72
Research Website
https://doi.org/10.1186/s44147-025-00580-5
Research Year
2025

Temperature Estimation of Thin Shape Memory Alloy Springs in a Small-Scale Hip Exoskeleton with System Identification and Adaptive Control

Research Abstract

This study presents a small-scale hip exoskeleton incorporating bi-directional artificial muscles constructed with springs of Shape Memory Alloy (SMA). The prototype can effectively support hip motion in both extension and flexion, spanning an angular range of  to . Experiments for thermo-mechanical characterization were executed to assess the performance of the SMA muscles throughout the entire motion range. The outcomes not only confirmed the suitability of the SMA muscles for the designed exoskeleton but also provided valuable insights into their behavior and capabilities. System identification experiments were carried out to establish an accurate transfer function, guiding the tuning of Proportional-Integral-Derivative (PID) controllers for enhanced motion-control effectiveness. The safety of the SMA system was addressed with a focus on preventing overheating. Challenges in accurately measuring the temperature of a thin spring were overcome by utilizing two thermocouples for each SMA springs group. Additionally, conventional SMA temperature measurement methods, such as infrared and resistance-based techniques, are limited by high cost, nonlinearity, and small range. This study presents a model-based temperature estimation algorithm that integrates a heat transfer model, electrical input data, and thermocouple data to enable accurate and real-time SMA temperature estimation without additional sensors, offering a cost-effective and reliable alternative. To evaluate the small hip prototype and its controller capabilities, control experiments were executed for both stepping and sinusoidal trajectories. The exoskeleton successfully tracked the desired trajectories, showing its precision. Moreover, system performance under adaptive control was further investigated, revealing an RMSE of  940 in sinusoidal trajectory experiments, indicating reliable disturbance rejection in the angle measurements.

Research Authors
Ali, Hussein F. M., Youngshik Kim, Ejaz Ahmad, and Shuaiby Mohamed.
Research Date
Research Journal
Actuators
Research Publisher
MDPI
Research Vol
15
Research Year
2026
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