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31,291 Article Results

Detection and classification of thyroid diseases using ultrasound images through deep learning techniques

10.11591/ijece.v16i5.pp2806-2818
Kamal Subedi , Akash Kumar Yadav , Lochan Paudel
Thyroid diseases remain one of the significant public health issues around the world, with thyroid nodules estimated to be prevalent among approximately 30 to 50% of the adult population through ultrasound imaging screening processes. Determination of the nature of the thyroid nodules in a patient's body is vital for ensuring effective treatment options since early detection of any malignant nodule will result in positive treatment results. The problem with such an analysis is the fact that the visual appearance of both benign and malignant nodules resembles each other in ultrasonic images. Therefore, a two-stage deep learning-based model for automatic detection and classification of thyroid nodules in ultrasound images was developed in this paper. At the first stage, the proposed framework applied Attention U-Net segmentation to identify the region of interest (ROI) for thyroid nodules in ultrasound images. Expert-drawn pixel-level annotations of thyroid nodules were not available; hence, pseudo-labels were used in training. They were obtained by applying CLAHE, Otsu thresholding, and morphological operations. In the second stage, a customized CNN network was applied to classify the segmented thyroid region into either benign or malignant classes. Data augmentation using the Mixup and CutMix techniques helped reduce the risk of overfitting, enhancing the model's generalizability. This experiment was tested on 480 ultrasound images gathered from two teaching hospitals in Nepal. The proposed framework shows that segmentation with weak supervision along with classification using deep learning can provide efficient diagnosis of thyroid nodules even with minimal medical data annotation. Through 3-fold stratified cross-validation, the Attention U-Net achieved a Dice Score of 0.8772 and IoU of 0.7873 for segmentation, while the classification stage obtained an overall accuracy of 96.73%, a specificity rate of 97.89%, and a mean ROC-AUC of 94.60%.
Volume: 16
Issue: 5
Page: 2806-2818
Publish at: 2026-10-01

Label-free acoustic monitoring of honeybee swarming: An unsupervised online learning approach

10.11591/ijece.v16i5.pp2483-2493
Abdelmadjid Guessoum Graba , Djoher Dalila Graba
Colony losses caused by honeybee swarming remain a major operational chal lenge because departure occurs within minutes, although acoustic changes be gin tens of minutes earlier and could allow timely intervention if detected reli ably. Current detection systems miss this window because the circadian rhythm of individual hive acoustics is not modelled, making it impossible to separate genuine pre-swarming drift from normal day-to-night spectral variation. Re cursive least squares is used to estimate a colony-specific circadian baseline, Mahalanobis distance scoring is applied to quantify deviations, and BOCPD ac cumulates Bayesian evidence of a regime shift, with a threshold derived from warmup data guaranteeing a controlled false alarm rate without labelled record ings and regardless of bee race, season, or microphone placement. A controlled simulation was used for evaluation, yielding 3.5× higher precision than the best label-free baseline, swarm anticipation exceeding 25 minutes before departure, and a false alarm rate held at the nominal 5% target. The low per-frame cost and memory footprint make this algorithm deployable on resource-constrained embedded devices, enabling continuous autonomous hive monitoring without expert supervision.
Volume: 16
Issue: 5
Page: 2483-2493
Publish at: 2026-10-01

Binary BAT algorithm with greedy repair for the discounted 0-1 knapsack problem

10.11591/ijece.v16i5.pp2680-2687
Tung Khac Truong
The discounted 0-1 knapsack problem (D0-1KP) generalizes the classical knapsack problem by partitioning items into groups of three, in which the third item of every group represents a discounted bundle of the first two and at most one item per group may be loaded. This grouping constraint enlarges the search space and makes the problem markedly harder than its classical counterpart. This paper presents BBAT, a binary bat algorithm for the D0-1KP. Bat velocities are mapped to selection probabilities through a sigmoid transfer function, and a greedy repair-and-optimization operator restores feasibility while raising the profit of every candidate solution. The algorithm keeps the small parameter set of the original bat metaheuristic, which limits the tuning effort required before deployment. BBAT was assessed on 14 benchmark instances drawn from the inverse strongly correlated and strongly correlated families, with 30 independent runs per instance. Against two elite genetic algorithms, BBAT improved the best profit found on 12 of the 14 instances and improved the mean profit on 7 of them. The gain in mean profit is concentrated on the inverse strongly correlated family, whereas on strongly correlated instances BBAT attains better peaks at the cost of higher run-to-run variance. These results identify BBAT as a competitive but variance-sensitive solver for the D0-1KP.
Volume: 16
Issue: 5
Page: 2680-2687
Publish at: 2026-10-01

Functional safety approach for thermal runaway in battery management systems

10.11591/ijece.v16i5.pp2405-2416
Nouhaila Belmajdoub , Rachid Lajouad , Abdelmounime El Magri , Soukaina Boudoudouh
Forecasting demand for autonomous power storage and supply systems for electric vehicles (EV) has become a key area of research. The rapid popularization of EVs is heavily based on the reliability and safety of rechargeable energy storage systems (ESSs), especially lithium-ion batteries (LIBs). Although these batteries offer high energy density and efficiency, they remain vulnerable to hazardous events such as thermal runaway, leading to severe consequences, including fire and explosion. This paper presents a methodology to fulfill the functional safety of BMS thermal runaway according to ISO 26262 standard. The approach integrates hazard analysis and risk assessment (HARA), the formulation of safety goals (SG), and the specification of functional and technical safety requirements (FSR and TSR). To strengthen assurance, safety contracts based on battery chemistry and specifications are established and linked to structured safety cases using Goal Structuring Notation (GSN). The proposed methodology is validated through simulations in MATLAB Simulink, demonstrating how dynamic safety assurance can detect deviations, trigger control actions, and update safety cases to prevent unsafe states. The results show that the framework effectively minimizes the risks related with over-current, over-voltage, and over-temperature conditions, thus contributing to regulatory compliance and increased confidence in the safety of EVs.
Volume: 16
Issue: 5
Page: 2405-2416
Publish at: 2026-10-01

An impact of activation functions on CNN-Bi-LSTM SoC estimation for Li-Ion batteries

10.11591/ijece.v16i5.pp2357-2364
Monica K. M. , Abhay A. Deshpande
Estimation of state of charge (SoC) in Li-ion batteries has been accomplished by many methods over couple of years. Every research in this domain majorly focusses on improving accuracy of estimation and some in exploring new algorithms. In this regard, we worked in analyzing the accuracy of estimation of SoC of sophisticatedly accurate techniques. A data-driven SoC estimation using deep neural network architectures (CNN) were collaborated with different activation functions like global pooling, exponential linear unit, Leaky rectified linear unit on convolutional neural network (CNN) and bidirectional-long short-term memory (Bi-LSTM) models. The performance of all these models was evaluated using quantitative error analysis and qualitative signal tracking studies to compare the estimated and actual SoC trajectory. This work consolidates the performances of different models and helps realize how best a fusion model works on the best accuracy in estimation.
Volume: 16
Issue: 5
Page: 2357-2364
Publish at: 2026-10-01

PMGHWO: A particle-guided adaptive grey wolf optimizer for large-scale traveling salesman problems

10.11591/ijece.v16i5.pp2819-2835
Hanadi A. Alshawabkah , Ayman Algafaan
The traveling salesman problem (TSP) remains challenging for metaheuristic algorithms, especially as the number of cities increases. This study proposes the particle-guided adaptive grey wolf optimizer (PMGHWO), which combines grey wolf optimizer (GWO)-based leadership guidance with crossover, particle-guided perturbation, and adaptive local refinement. PMGHWO was evaluated on ten TSPLIB instances and compared with grey wolf optimizer (GWO), genetic algorithms (GA), particle swarm optimization (PSO), whale optimization algorithm (WOA), and Harris Hawks optimization (HHO) under the same experimental conditions. The proposed method achieved shorter average tours on all tested instances, with reductions of 18.75% compared with GWO, 19.77% with HHO, 23.30% with GA, 39.08% with WOA, and 57.51% with PSO. Friedman and Wilcoxon tests confirmed significant differences between PMGHWO and the compared methods. The ablation study showed that adaptive refinement had the strongest effect on solution quality, while the influence of particle-guided perturbation and crossover varied across the benchmark instances. Although PMGHWO required more computation than the original GWO, its runtime remained competitive with several of the other methods. Overall, the results show that PMGHWO is a promising approach for TSP optimization and warrants further evaluation on larger and more complex combinatorial problems.
Volume: 16
Issue: 5
Page: 2819-2835
Publish at: 2026-10-01

Real-time multimodal fatigue detection using facial vision and alert integration via ESP32 for occupational health applications

10.11591/ijece.v16i5.pp2750-2768
Andrés Enrique Rojas Primo , Alfredo Lazaro Gutierrez , Felix Pucuhuayla-Revatta
Early detection of work fatigue is a major challenge in industrial settings due to the lack of non-invasive, accessible, and low-cost systems capable of operating in real time. In this context, this research proposes a multimodal real-time fatigue detection system using facial vision and artificial intelligence, aimed at risk prevention and promoting occupational health. The system integrates geometric and behavioral parameters, such as eye aspect ratio (EAR), head tilt, and mouth opening, processed on a Raspberry Pi 5 using MediaPipe and a hybrid convolutional neural network (CNN) MobileViT model. Visual and audible alerts are managed by an ESP32 microcontroller using the message queuing telemetry transport (MQTT) protocol, while a graphical interface developed in Tkinter allows real-time monitoring of operator status. Experimental results, evaluated in a simulated work environment using AI-generated synthetic videos, show an accuracy greater than 97% and a latency of less than 250 ms, confirming the system's effectiveness in the early detection of signs of drowsiness and attention deficit. In conclusion, the proposal represents a non-invasive, scalable, and efficient solution that combines computer vision, deep learning, and the Internet of Things (IoT) to strengthen workplace safety and well-being.
Volume: 16
Issue: 5
Page: 2750-2768
Publish at: 2026-10-01

CLARA: a unified hybrid ai-human receptionist framework using WebRTC and Monorepo architecture

10.11591/ijece.v16i5.pp2769-2781
Dhanush Sridhar Babu , Nagashree Nagesh , Amble Nagendra Aashuthosh , Adithya Nimmala Chandra , Muthusamy Naveen Kumar
The rapid digitalization of enterprise infrastructure has caused a major change in institutional communication. This change requires the traditional front desk to transform into a high-tech center for security and logistics. However, current automated solutions often create what is known as the “automation paradox.” In this situation, removing human oversight increases the importance and complexity of the remaining interactions. This work outlines the design, implementation, and evaluation of conversational low-latency AI receptionist agent (CLARA). CLARA is a new hybrid system which solves the problems of unattended kiosks by combining a conversational AI, which uses the Google Gemini API, with a low-latency, real-time WebRTC video calling system. The design features a strong 3-Tier Monorepo built with React, TypeScript, Express.js, Socket.IO, and PostgreSQL. This setup ensures type safety and consistency in the code across the entire stack. Key contributions of this project include a custom Socket.IO signaling server for secure peer-to-peer connections, a “Human-in-the-Loop” workflow that reduces handoff issues, and an “Offline-First” strategy ensuring the system keeps working during network disruptions. Performance tests show that CLARA achieves less than 200 ms glass-to-glass latency and handles high traffic well, proving it is an effective and reliable solution for modern visitor management.
Volume: 16
Issue: 5
Page: 2769-2781
Publish at: 2026-10-01

Real-time depth measurement and stability control of AUV using regression approximation and filtered pressure data

10.11591/ijece.v16i5.pp2417-2430
Senanjung Prayoga , Dhaniel Beny Wardhana , Ryan Satria Wijaya
This paper presents the development and experimental validation of a prototype-scale autonomous underwater vehicle (AUV) depth control system using a proportional-integral-derivative (PID) controller with depth feedback from a SEN0257 water-pressure sensor. Raw sensor readings are filtered and calibrated using linear regression, reducing the depth estimation error, as indicated by a decrease in root mean square error (RMSE) from 1.88 to 0.63 cm. The calibrated depth signal is implemented in real time as the feedback source for closed-loop control on the testbed. Controller performance is evaluated by comparing two tuning strategies: Ziegler–Nichols (ZN) closed-loop tuning and manual fine-tuning. Experiments were conducted at depth setpoints of 70 and 100 cm under consistent pool conditions, and additional trials were performed while the AUV executes forward motion to assess robustness under dynamic disturbances. System responses are quantified using rise time, overshoot, settling time, and steady-state error. Results show that calibration significantly improves sensor suitability for feedback, while the fine-tuned PID controller produces a more stable depth response with lower overshoot, smaller steady-state error, and shorter settling time than the ZN controller, despite the faster initial rise achieved by ZN tuning. Overall, combining calibrated pressure-based depth estimation with fine-tuned PID gains enables stable and accurate depth regulation for prototype AUV operation.
Volume: 16
Issue: 5
Page: 2417-2430
Publish at: 2026-10-01

A chip level design of a multi-mode compressive sensing image sensor

10.11591/ijece.v16i5.pp2393-2404
Zahra Sepehri , Sayed Masoud Sayedi , Ehsan Yazdian
This paper presents the full chip-level design of a multi-mode CMOS vision sensor, emphasizing the detailed implementation of its circuit architecture. The proposed chip incorporates our previously developed photodiode sensing array together with the on-chip design of control circuitry. By embedding these building blocks, the chip enables pixel-level compressive sensing and supports dual operation modes, allowing the transmission of image data in both compressed and non-compressed formats. In either mode, the sensor is capable of capturing both scene images and difference images between consecutive video frames, operating at a frame rate of 40 fps. A 64*64 vision chip is implemented using TSMC 0.18um standard CMOS technology. In the normal scene image mode, with compression (N-C) and  without compression (N-nC), the structure consumes 36.99uW and 37.09uW, respectively. Meanwhile, in the difference scene image mode, with compression (D-C) and  without compression (D-nC), it consumes 38.67uW and 38.75uW, respectively.
Volume: 16
Issue: 5
Page: 2393-2404
Publish at: 2026-10-01

Robust resource allocation in multi-cell UE-specific RIS-assisted D2D relay networks under imperfect CSI

10.11591/ijece.v16i5.pp2575-2594
Kayode Popoola , Ayodeji Ajani , Stuart Nicholson , Muheeb Ahmed , Srilatha Narayangari Pamuri , Ibrahim Bala Alhassan
Device-to-device (D2D) communication enhances spectral efficiency but remains constrained by limited transmission range, underlay interference, and the half-duplex overhead of conventional relays. User equipment-specific reconfigurable intelligent surfaces (UE-RIS) offer a promising alternative by enabling passive beamforming to strengthen D2D links without additional spectrum consumption. However, existing studies typically assume perfect channel state information (CSI) and single-cell operation, limiting their applicability to practical deployments. This paper proposes a robust multi-cell resource allocation (RMRA) framework for UE-RIS-assisted D2D relay networks under imperfect CSI. A hybrid uncertainty model is adopted, combining statistical Gauss-Markov CSI errors for intra-cell links with bounded norm-ball uncertainty for inter-cell links. The joint optimisation of resource reuse, transmit power allocation, and RIS phase configuration is formulated as a stochastic mixed-integer nonlinear program that maximises network spectral efficiency while satisfying outage and quality-of-service constraints. To efficiently solve the problem, a three-stage algorithm is proposed comprising distance-pruned Hungarian assignment, robust power control using Bernstein-type inequality and S-procedure based semidefinite programming, and soft actor-critic (SAC) based passive beamforming. Simulation results show that RMRA achieves a 94% D2D access rate at light load and over 75% at full load, improves sum spectral efficiency by 34.7% and 70.2% over AF relaying and direct D2D, respectively, attains 118.5 bits/s/Hz/W energy efficiency, and maintains 30.2 bits/s/Hz under severe CSI uncertainty.
Volume: 16
Issue: 5
Page: 2575-2594
Publish at: 2026-10-01

Impact of optimal power flow on power quality in a low voltage three-phase network: application to a real case in Lubumbashi (DR Congo)

10.11591/ijece.v16i5.pp2304-2320
David Milambo Kasumba , Guy Nkulu Wa Ngoie , Hyacinthe Tungadio Diambomba , Jean-Paul Katond Mbay , Bonaventure Banza WA Banza
Low-voltage distribution systems (LVDS) in rapidly growing Sub-Saharan African cities frequently experience severe phase imbalance, voltage deviations, and high technical losses due to overloaded and poorly balanced feeders. Despite the increasing availability of advanced optimization techniques, their application to real low-voltage networks in developing countries remains limited. This study investigates the impact of an unbalanced three-phase optimal power flow (OPF) framework on the power quality and operational performance of a real low-voltage distribution network located in Kamalondo, Lubumbashi (Democratic Republic of the Congo). The network model was parameterized using field measurements collected between September and December 2024. The optimization problem was formulated as a mixed-integer nonlinear programming (MINLP) model and solved using the interior point method implemented in Pandapower. The proposed framework simultaneously minimizes active power losses and mitigates phase imbalance while respecting voltage and thermal operating constraints. Simulation results demonstrate significant improvements in network performance. The minimum phase-to-neutral voltage increased from 198 V to 210 V, while the maximum voltage decreased from 232 V to 226 V, improving compliance with power quality standards. The maximum current phase was reduced by 15%, and total active power losses decreased by 30%. Furthermore, the voltage unbalance factor (VUF) was reduced from 8% to 3% through optimized phase allocation and power redistribution. These results demonstrate that unbalanced three-phase OPF constitutes an effective and practical solution for improving power quality, reducing technical losses, and enhancing the operational reliability of heavily loaded low-voltage networks in developing urban environments.
Volume: 16
Issue: 5
Page: 2304-2320
Publish at: 2026-10-01

An artificial intelligence-based stacking ensemble framework for smart irrigation pump control using IoT sensor data

10.11591/ijece.v16i5.pp2652-2663
Sarra Gourari , Wafa Difallah , Belkacem Draoui
Efficient water management is essential for sustainable agricultural production, particularly in arid and semi-arid regions where water resources are limited. Machine-learning-based irrigation systems can support automated pump-operation decisions using environmental and soil-related sensor data. However, most previous studies have focused on individual machine-learning models, while the application of stacked ensembles to binary irrigation pump-status prediction remains relatively limited. This study proposes a stacking-based framework for predicting irrigation pump operation in an ON/OFF classification setting. The framework uses environmental and soil-related variables, including soil moisture, temperature, humidity, and a numerical time-related feature. Random forest (RF), extreme gradient boosting (XGBoost), and multilayer perceptron models were trained as base learners, and their out-of-fold (OOF) predictions were combined using a logistic-regression meta-learner. The models were evaluated on a held-out test set using accuracy, precision, recall, specificity, and F1-score. The individual models achieved accuracies ranging from 97.34% to 99.95%, with XGBoost providing the best individual performance. The proposed stacking ensemble achieved 99.97% accuracy, 99.94% precision, 100.00% recall, 99.94% specificity, and a 99.97% F1-score. Compared with XGBoost, the ensemble further refined predictive performance, improving accuracy by 0.02 percentage points and F1-score by 0.01 percentage points while achieving complete elimination of false negatives (100.00% recall). These results demonstrate the potential of stacked ensemble learning to improve binary pump-operation prediction and support data-driven irrigation management in water-limited environments.
Volume: 16
Issue: 5
Page: 2652-2663
Publish at: 2026-10-01

Per-channel margin and nonlinear asymmetry in an eight-channel optical distribution network

10.11591/ijece.v16i5.pp2559-2574
Mohammed Kareem Al-Swaiedi , Ahmed Ali Skaiky
The physical layer of a wavelength-division-multiplexed optical distribution network for smart-city Internet-of-Things access is almost always reported from a single simulation run, which says nothing about its stability. This paper characterized an eight-channel C-band link over 25 km of standard single-mode fibre, modelled in OptiSystem, across thirty independent replications yielding 240 per-channel Q-factor observations. Every channel cleared the Q ≥ 6 threshold in every replication, with a system mean of 8.66, a per-channel 95% confidence interval never wider than 0.46, and a worst realization of 6.64 on the weakest channel, so the link held a stable margin rather than crossing the boundary between runs. The per-channel Q-factors followed a U-shape across the wavelength grid with its minimum at the centre, and a short-reach reference at 1 km showed that two thirds of the edge-to-interior asymmetry was established within the first kilometre. A launch-power sweep placed the usable ceiling between 10 and 13 dBm. A control experiment with the fibre nonlinearity disabled collapsed the edge-to-interior ratio from 1.354 to 1.038, establishing that 89% of the asymmetry was nonlinear in origin, while a four-wave-mixing coherence length of 0.74 km against the 25 km span identified cross-phase modulation as the mechanism.
Volume: 16
Issue: 5
Page: 2559-2574
Publish at: 2026-10-01

Design science research in developing a religious chatbot based on Bulugh al-Maram

10.11591/ijece.v16i5.pp2782-2794
Aris Tjahyanto , Irmasari Hafidz , Faizal Johan Atletiko
Chatbots have recently gained significant popularity. For instance, ChatGPT has become a preferred tool for many individuals seeking instant answers without relying on human responses. This immediacy sets chatbots apart from books, which require users to search for information manually. This time-consuming process does not align with millennials' preference for convenience and efficiency. Studying hadith independently using the Bulugh al-Maram book demands considerable time and effort. The limited use of natural language processing technologies in religious chatbots restricts their ability to handle complex inquiries effectively. A chatbot capable of answering hadith-related questions could greatly assist the public in studying hadith texts by providing direct responses without extensive searching. This chatbot was designed for web browsers, utilizing deep learning as its core technology. This research led to the development of a chatbot prototype for learning hadith from Bulugh al-Maram. Built using the design science research (DSR) methodology, the prototype achieves an intent recognition rate (IRR) of 86.82%. However, its capabilities are below the BERT model, demonstrating a strong ability to accurately interpret user questions and statements.
Volume: 16
Issue: 5
Page: 2782-2794
Publish at: 2026-10-01
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