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Electronics, Volume 13, Issue 23 (December-1 2024) – 280 articles

Cover Story (view full-size image): The integration of a robot into an Ambient Assisted Living (AAL) environment to extend its services has been explored in various projects, highlighting new opportunities through their symbiosis. This requires both systems to share context-derived knowledge. Using data from environmental sensors, the robot can determine the person's location, assess the need for physical activity, or adjust objects like chairs to perform tasks. This work presents an AAL system design where IoT devices and a robot coexist as connected but independent elements within a cyber-physical system-of-systems. The IoT setup includes cameras to track activity and sensors to monitor heart or breathing rates. While the focus is on context-aware knowledge sharing, example use cases are provided. View this paper
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15 pages, 2232 KiB  
Article
Mixed Label Assignment Realizes End-to-End Object Detection
by Jiaquan Chen, Changbin Shao and Zhen Su
Electronics 2024, 13(23), 4856; https://doi.org/10.3390/electronics13234856 - 9 Dec 2024
Viewed by 388
Abstract
Currently, detectors have made significant progress in inference speed and accuracy. However, these detectors require Non-Maximum Suppression (NMS) during the post-processing stage to eliminate redundant boxes, which limits the optimization of model inference speed. We first analyzed the reason for the dependence on [...] Read more.
Currently, detectors have made significant progress in inference speed and accuracy. However, these detectors require Non-Maximum Suppression (NMS) during the post-processing stage to eliminate redundant boxes, which limits the optimization of model inference speed. We first analyzed the reason for the dependence on NMS in the post-processing stage. The result showed that a score loss in a one-to-many label assignment leads to the presence of high-quality redundant boxes, making them difficult to remove. To realize end-to-end object detection and simplify the detection pipeline, we propose herein a mixed label assignment (MLA) training method, which uses one-to-many label assignment to provide rich supervision signals, alleviating the performance degradation, and we eliminate the need for NMS in the post-processing stage by using one-to-one label assignment. Additionally, a window feature propagation block (WFPB) is introduced, utilizing the inductive bias of images to enable feature sharing in local regions. Through these methods, we conducted experiments on the VOC and DUO datasets; our end-to-end detector MA-YOLOX achieved 66.0 mAP and 52.6 mAP, respectively, outperforming the YOLOX by 1.7 and 1.6. Additionally, our model performed faster than other real-time detectors without NMS. Full article
(This article belongs to the Special Issue Applications of Computer Vision, 3rd Edition)
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<p>MA-YOLOX network architecture.</p>
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<p>Visualization of confidence heatmaps predicted by various methods. The image is sourced from the VOC2007 test set and contains examples: ‘Man’ and ‘horse’. The methods are sequentially trained using one-to-many matching (Baseline), one-to-one matching (O2O), and mixed label allocation (MLA) proposed in this paper. The heatmaps represent the confidence scores for predictions at the “P4, P5” scale. It can be found that the O2O and MLA methods significantly reduce the redundant prediction of the same object compared to Baseline.</p>
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<p>The end-to-end training method of mixed label assignment (MLA). For input images, based on the model’s predictions of regression, classification, and confidence information, compute the matching cost and choose positive samples, then use the best positive sample ‘1’ to optimize the confidence prediction head by one-to-one label assignment; the positive samples ‘1, 2, 3, 4’ are optimized by performing one-to-many matching for the regression and classification.</p>
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<p>(<b>a</b>) The basic composition of the YOLOX backbone’s dark module; (<b>b</b>) the window feature propagation block (WFPB).</p>
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<p>Visualization of model detection results for the VOC dataset.</p>
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<p>Visualization of detection results with or without NMS by YOLOX and MA-YOLOX.</p>
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<p>Visualization of ablation experiment results.</p>
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15 pages, 5906 KiB  
Article
A Tight Load Regulation Hysteretic Boost Converter with Compact and Energy-Efficient Anti-Phase Emulated Current Control
by Xiaohui Hu, Wanyuan Qu, Xu Yang and Yong Ding
Electronics 2024, 13(23), 4855; https://doi.org/10.3390/electronics13234855 - 9 Dec 2024
Viewed by 401
Abstract
This paper presents a novel, compact, and energy-efficient hysteretic boost converter that employs an anti-phase AC-coupling emulate current control. The proposed scheme utilizes a two-transistor current emulator and a comparator, which allow for fast transient responses and tight closed-loop regulations. This converter was [...] Read more.
This paper presents a novel, compact, and energy-efficient hysteretic boost converter that employs an anti-phase AC-coupling emulate current control. The proposed scheme utilizes a two-transistor current emulator and a comparator, which allow for fast transient responses and tight closed-loop regulations. This converter was fabricated using a 180 nm CMOS process and was capable of regulating a 5 V output with a 400 mA load capacity from an input voltage range of 2.7 V to 4.5 V. The experimental results demonstrate that the proposed anti-phase AC-coupling emulate current controlling and single hysteretic comparator controlling scheme show lower power/circuit complexity and better static and transient performance. Specifically, under load transitions ranging from 0 mA to 300 mA, the converter exhibits over/undershoot voltages of 38 mV and −42 mV, respectively. Furthermore, the measured load and line regulation performances are 5 mV/A and 2.3 mV/V, respectively. Overall, this study offers a practical and efficient solution for boosting voltage levels while maintaining stable and precise regulation. Full article
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<p>The hysteretic voltage mode buck converter.</p>
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<p>The hysteretic current-mode buck converter: (<b>a</b>) basic working principle; (<b>b</b>) typical circuit implementation.</p>
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<p>The different summing <span class="html-italic">i<sub>L</sub></span>-<span class="html-italic">V<sub>O</sub></span> waveforms of the buck converter and boost converter.</p>
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<p>Various inductor current sensing techniques.</p>
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<p>Previously reported hysteretic boost converters: (<b>a</b>) using a high gain amplifier; (<b>b</b>) using three gm stages for V<sub>O</sub> and I<sub>L</sub> summing.</p>
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<p>System architecture of the proposed CM hysteretic control boost converter.</p>
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<p>The summing V<sub>L</sub>−V<sub>FB</sub> operating waveform of the proposed hysteretic Boost converter.</p>
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<p>DCR error cancelation in the proposed hysteretic boost converter.</p>
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<p>The summing load-transient waveforms of V<sub>O</sub>-I<sub>L</sub>: (<b>a</b>) the conventional control scheme; (<b>b</b>) the proposed anti-phase AC-coupling emulated current control.</p>
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<p>The equivalent model of the proposed hysteretic boost converter.</p>
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<p>The comparisons of the control-to-output transfer function between the calculated and simulated results.</p>
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<p>Simulations of frequency response of the proposed hysteretic boost under different load conditions.</p>
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<p>The frequency regulation phase-locked loop. (<b>a</b>) Circuit implementation; (<b>b</b>) simulated waveforms.</p>
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<p>The frequency regulation phase-locked loop. (<b>a</b>) Circuit implementation; (<b>b</b>) simulated waveforms.</p>
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<p>Circuit implementation of high-speed hysteretic window tunable comparator.</p>
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<p>(<b>a</b>) Layout; (<b>b</b>) chip die photograph.</p>
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<p>Measurement output voltage V<sub>O</sub> and inductor current I<sub>L</sub> waveforms under load transitions between 0 mA and 300 mA with V<sub>IN</sub> = 3.3 V.</p>
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<p>Measurement results: input line transitions with load current at 300 mA.</p>
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<p>Measurement results: (<b>a</b>) summarized load and line regulation errors; (<b>b</b>) power efficiency and switching frequency versus load current.</p>
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12 pages, 325 KiB  
Article
Supporting the Characterization of Preeclampsia Patients Through Descriptive and Clustering Analysis
by Franklin Parrales-Bravo, Rosangela Caicedo-Quiroz, Leonel Vasquez-Cevallos, Elena Tolozano-Benites, Jorge Charco-Aguirre, Julio Barzola-Monteses and Lorenzo Cevallos-Torres
Electronics 2024, 13(23), 4854; https://doi.org/10.3390/electronics13234854 - 9 Dec 2024
Viewed by 375
Abstract
One of the most common causes of maternal death during pregnancy is preeclampsia. A deeper understanding of the patient’s features can aid in the hospital’s clinical care distribution. However, at the IESS Los Ceibos Hospital, these types of studies have not been carried [...] Read more.
One of the most common causes of maternal death during pregnancy is preeclampsia. A deeper understanding of the patient’s features can aid in the hospital’s clinical care distribution. However, at the IESS Los Ceibos Hospital, these types of studies have not been carried out for preeclampsia. Therefore, in this work, we describe the application of descriptive and clustering analysis to characterize preeclamptic patients. Preeclamptic patients treated at the IESS Los Ceibos Hospital in Guayaquil comprised the dataset used in this study. Descriptive and clustering analysis allowed us to find that severe preeclampsia (O141) is the most common diagnosis when preeclamptic patients arrive at the hospitalization unit, representing 79.5% of the cases. Moreover, women whose maternal age falls between 26 and 35 years have the highest prevalence of preeclampsia, representing 55.4% of the cases. Finally, adult patients in their late 30s or older are often diagnosed with severe preeclampsia (O141) and often require many hours of hospital care during the first two visits. These findings will help to generate care and prevention policies, such as the use of a low dose of aspirin, in these age groups to avoid the complications that preeclampsia can cause. Full article
(This article belongs to the Special Issue Medical Applications of Artificial Intelligence)
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<p>Summary of the aspects that will be reviewed in this study.</p>
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<p>Boxplot of the ages of patients with preeclampsia when ordered by age.</p>
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<p>Number of preeclamptic patients by age.</p>
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<p>Bar diagram of the diagnosis of preeclampsia patients treated in the hospitalization unit.</p>
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<p>Frequencies of inpatients with severe preeclampsia by age.</p>
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<p>Silohuette coefficient obtained by considering 2, 3, 4 and 5 clusters using the PAM method.</p>
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20 pages, 16744 KiB  
Article
Bearing Fault Diagnosis Method Based on Osprey–Cauchy–Sparrow Search Algorithm-Variational Mode Decomposition and Convolutional Neural Network-Bidirectional Long Short-Term Memory
by Zhiyuan Xiong, Haochen Jiang, Da Wang, Xu Wu and Kenan Wu
Electronics 2024, 13(23), 4853; https://doi.org/10.3390/electronics13234853 - 9 Dec 2024
Viewed by 344
Abstract
To solve the problem of the low diagnosis rate of early weak faults of rolling bearings, a novel bearing fault diagnosis method based on Variational Mode Decomposition (VMD) and convolutional neural network (CNN)−Bidirectional Long Short-Term Memory (BiLSTM) was proposed. Based on the basic [...] Read more.
To solve the problem of the low diagnosis rate of early weak faults of rolling bearings, a novel bearing fault diagnosis method based on Variational Mode Decomposition (VMD) and convolutional neural network (CNN)−Bidirectional Long Short-Term Memory (BiLSTM) was proposed. Based on the basic Sparrow Search Algorithm, the tent chaotic mapping, the Osprey Optimization Algorithm, and the Cauchy mutation were used to enhance the global search ability of the algorithm. To improve the accuracy of fault diagnosis, the BiLSTM layer is introduced into CNN to preserve the global and local features to the maximum extent. The experimental results show that VMD avoids the end effect problem in Empirical Mode Decomposition (EMD). The accuracy rate of the diagnosis model based on CNN-BILSTM reached 97.6667%, which was higher than that of the common diagnosis model. Full article
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<p>Chaos mapping function.</p>
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<p>Standard normal distribution and Cauchy distribution function.</p>
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<p>F1 convergence curves.</p>
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<p>F2 convergence curves.</p>
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<p>F3 convergence curves.</p>
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<p>F4 convergence curves.</p>
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<p>A technical approach for identifying bearing fault problems.</p>
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<p>OCSSA optimizes the VMD algorithm flowchart.</p>
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<p>CNN-BiLSTM model structure.</p>
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<p>The time-domain diagram of four states of bearings (<b>a</b>–<b>d</b>) are normal signal, inner circle malfunction, outer ring fault, and rolling element malfunction, respectively.</p>
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<p>The frequency-domain diagram of four states of bearings (<b>a</b>–<b>d</b>) are normal signal, inner circle malfunction, outer ring fault, and rolling element malfunction, respectively.</p>
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<p>(<b>a</b>,<b>b</b>) Normal state of VMD.</p>
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<p>(<b>a</b>,<b>b</b>) VMD of the inner ring fault.</p>
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<p>(<b>a</b>,<b>b</b>) VMD of the outer ring fault.</p>
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<p>(<b>a</b>,<b>b</b>) Rolling element fault of VMD.</p>
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<p>Experimental results of the fault diagnosis model (<b>a</b>–<b>d</b>) are CNN, BiLSTM, CNN-LSTM, and CNN-BiLSTM, respectively.</p>
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<p>Experimental results of the fault diagnosis model (<b>a</b>–<b>d</b>) are CNN, BiLSTM, CNN-LSTM, and CNN-BiLSTM, respectively.</p>
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<p>Time-frequency-domain waveform diagram of inner ring faulty bearing under different load states.</p>
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<p>Accuracy rates of various algorithms under different load conditions.</p>
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<p>EMD diagram of the simulated signal.</p>
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<p>VMD diagram of the simulated signal.</p>
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<p>VMD diagram for parameter K = 4.</p>
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13 pages, 2146 KiB  
Article
Developing an Alert System for Agricultural Protection: Sika Deer Detection Using Raspberry Pi
by Sandhya Sharma, Buchaputara Pansri, Suresh Timilsina, Bishnu Prasad Gautam, Yoshifumi Okada, Shinya Watanabe, Satoshi Kondo and Kazuhiko Sato
Electronics 2024, 13(23), 4852; https://doi.org/10.3390/electronics13234852 - 9 Dec 2024
Viewed by 403
Abstract
Agricultural loss due to the overpopulation of Sika deer poses a significant challenge in Japan, leading to frequent human–wildlife conflicts. We conducted a study in Muroran, Hokkaido (42°22′56.1″ N–141°01′51.5″ E), with the objective of monitoring Sika deer and notifying farmers and locals. We [...] Read more.
Agricultural loss due to the overpopulation of Sika deer poses a significant challenge in Japan, leading to frequent human–wildlife conflicts. We conducted a study in Muroran, Hokkaido (42°22′56.1″ N–141°01′51.5″ E), with the objective of monitoring Sika deer and notifying farmers and locals. We deployed a Sika deer detection model (YOLOv8-nano) on a Raspberry Pi, integrated with an infrared camera that captured images only when a PIR sensor was triggered. To further understand the timing of Sika deer visits and potential correlations with environmental temperature and humidity, respective sensors were installed on Raspberry Pi and the data were analyzed using an ANOVA test. In addition, a buzzer was deployed to deter Sika deer from the study area. The buzzer was deactivated in the first 10 days after deployment and was activated in the following 20 days. The Sika deer detection model demonstrated excellent performance, with precision and recall values approaching 1, and a bounding box creation latency of 0.82 frames per second. Once a bounding box was established after Sika deer detection, alert notifications were automatically sent via email and the LINE messaging application, with an average notification time of 0.32 s. Regarding the buzzer’s impact on Sika deer, 35% of the detected individuals reacted by standing upright with alert ears, while 65% immediately fled the area. Analysis revealed that the time of day for Sika deer visits was significantly correlated with humidity (F = 8.95, p < 0.05), but no significant association with temperature (F = 0.681, p > 0.05). These findings represent a significant step toward mitigating human–wildlife conflicts and reducing agricultural production losses through effective conservation measures. Full article
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<p>Visualization of the research motivation.</p>
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<p>Circuit diagram for Raspberry Pi-based Sika deer monitoring and alert system.</p>
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<p>Workflow illustrating Sika deer real-time detection and alert mechanism.</p>
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<p>Components connected to the Raspberry Pi for Sika deer detection in the field: (<b>a</b>) external components housed inside a plastic box; (<b>b</b>) sensors, camera, and switch positioned outside the plastic box; (<b>c</b>) solar panel providing a continuous power supply; and (<b>d</b>) Raspberry Pi with components enclosed in a plastic box alongside a solar panel installed in the study field.</p>
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<p>Curves representing box and class loss for training and validation datasets.</p>
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<p>Performance metrics across multiple epochs.</p>
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<p>The number of herds observed daily before the buzzer activation was recorded. Day 1 represented the first day without the buzzer activation on the Raspberry Pi, followed by subsequent days.</p>
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<p>Images of individual Sika deer within each herd: (<b>a</b>) Herd 1, consisting of three individual Sika deer; and (<b>b</b>) Herd 2, consisting of two individual Sika deer.</p>
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<p>Visualization of alert mechanisms following Sika deer detection in captured images: (<b>a</b>) identification of Sika deer using bounding boxes in captured images; (<b>b</b>) alert notification via email; (<b>c</b>) alert notification through LINE application; and (<b>d</b>) analysis of Sika deer behavior following buzzer activation.</p>
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<p>Herd observations recorded at different times throughout the day, along with environmental temperature and humidity, after buzzer activation. The term “Day” refers to the number of days since the buzzer was activated; for example, “Day 1” indicates the first day after activation, “Day 4” refers to the fourth day, and so forth. The visualization only includes days when herds of Sika deer were observed, excluding days without any sightings.</p>
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23 pages, 4776 KiB  
Article
Research on Personalized Recommendation of Complementary Products Based on Demand Cross-Elasticity and Hypergraphs
by Ganglong Duan, Yutong Du and Yanying Shang
Electronics 2024, 13(23), 4851; https://doi.org/10.3390/electronics13234851 - 9 Dec 2024
Viewed by 337
Abstract
To improve recommendation systems, it is essential to enhance both their practicality and accuracy, thereby supporting users in making informed shopping decisions. Incorporating two types of product relationships can effectively achieve these goals: first, the product relationships, like complements, and second, the social [...] Read more.
To improve recommendation systems, it is essential to enhance both their practicality and accuracy, thereby supporting users in making informed shopping decisions. Incorporating two types of product relationships can effectively achieve these goals: first, the product relationships, like complements, and second, the social relationships among users. However, existing studies have paid little attention to user-side information or item-side information. This paper proposes a product recommendation model that utilizes cross-elasticity of demand and hypergraphs, referred to as Hg-CR. First, users and items build a hypergraph. The user–item interactions form the hyperedges. Also, users build a hypergraph between themselves based on their social relationships. Second, hypergraph attention networks (HANs) learn the relationships between nodes. They capture the key features of nodes and hyperedges with a high degree of adaptability. A community detection algorithm organizes users into groups for product recommendations by assessing their similarities. Within different communities, individuals seek complementary products based on the cross-elasticity theory of demand. Additionally, we provide recommendations for complementary products. Tests on real datasets show that the Hg-CR model is about 10% more accurate than the other baseline models. Full article
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<p>User–item hypergraph.</p>
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<p>User–user hypergraph.</p>
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<p>The calculation process of the hypergraph attention network.</p>
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<p>Architecture diagram of hypergraphic attention network.</p>
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<p>Social circle.</p>
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<p>Network structure.</p>
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<p>Social networks.</p>
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<p>Louvain algorithm.</p>
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<p>Hg-CR model.</p>
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<p>Comparison results of MAE for different clustering algorithms.</p>
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<p>RMSE comparison results of different clustering algorithms.</p>
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<p>Comparison results of MAE for different algorithms.</p>
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<p>Comparison results of RMSE for different algorithms.</p>
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<p>Figure (<b>a</b>) shows the effect of varying with the number of network layers on NDCG@10 and figure (<b>b</b>) shows the effect of varying with the number of network layers on Recall@10.</p>
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<p>Figure (<b>a</b>) shows the effect of varying with Droput rate on NDCG@10 and Figure (<b>b</b>) shows the effect of varying with Droput rate on Recall@10.</p>
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17 pages, 1061 KiB  
Review
A Review of Emerging Sensor Technologies for Tank Inspection: A Focus on LiDAR and Hyperspectral Imaging and Their Automation and Deployment
by Sergio Pallas Enguita, Chung-Hao Chen and Samuel Kovacic
Electronics 2024, 13(23), 4850; https://doi.org/10.3390/electronics13234850 - 9 Dec 2024
Viewed by 458
Abstract
This paper reviews various sensor technologies for tank inspection, focusing on Light Detection and Ranging (LiDAR) and Hyperspectral Imaging (HSI) as advanced solutions for corrosion detection. These technologies are evaluated alongside traditional methods such as ultrasonic, electromagnetic, and thermographic inspections. This review highlights [...] Read more.
This paper reviews various sensor technologies for tank inspection, focusing on Light Detection and Ranging (LiDAR) and Hyperspectral Imaging (HSI) as advanced solutions for corrosion detection. These technologies are evaluated alongside traditional methods such as ultrasonic, electromagnetic, and thermographic inspections. This review highlights their potential to enhance inspection accuracy, reduce the limitations of manual inspection, and support integrated data analysis for comprehensive asset management. Additionally, this paper proposes a pathway for automating these techniques to streamline inspection processes and improve implementation in practical applications. Full article
(This article belongs to the Special Issue Feature Review Papers in Electronics)
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<p>High-level overview of basic LiDAR.</p>
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<p>Implementation of Mobile LiDAR.</p>
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<p>Every pixel is represented through a spectrum of light values, also known as a pixel’s spectral signature. Here every plot represents the reading of the pixel in a different wavelength.</p>
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<p>Proposed workflow for data gathering is presented.</p>
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17 pages, 2114 KiB  
Article
Research on a Passenger Flow Prediction Model Based on BWO-TCLS-Self-Attention
by Sheng Liu, Lang Du, Ting Cao and Tong Zhang
Electronics 2024, 13(23), 4849; https://doi.org/10.3390/electronics13234849 - 9 Dec 2024
Viewed by 350
Abstract
In recent years, with the rapid development of the global demand and scale for deep underground space utilization, deep space has gradually transitioned from single-purpose uses such as underground transportation, civil defense, and commerce to a comprehensive, livable, and disaster-resistant underground ecosystem. This [...] Read more.
In recent years, with the rapid development of the global demand and scale for deep underground space utilization, deep space has gradually transitioned from single-purpose uses such as underground transportation, civil defense, and commerce to a comprehensive, livable, and disaster-resistant underground ecosystem. This shift has brought increasing attention to the safety of personnel flow in deep spaces. In addressing challenges in deep space passenger flow prediction, such as irregular flow patterns, surges in extreme conditions, large data dimensions, and redundant features complicating the model, this paper proposes a deep space passenger flow prediction model that integrates a Temporal Convolutional Network (TCN) and Long Short-Term Memory (LSTM) network. The model first employs a dual-layer LSTM network structure with a Dropout layer to capture complex temporal dynamics while preventing overfitting. Then, a Self-Attention mechanism and TCN network are introduced to reduce redundant feature data and enhance the model’s performance and speed. Finally, the Beluga Whale Optimization (BWO) algorithm is used to optimize hyperparameters, further improving the prediction accuracy of the network. Experimental results demonstrate that the BWO-TCLS-Self-Attention model proposed in this paper achieves an R2 value of 96.94%, with MAE and RMSE values of 118.464 and 218.118, respectively. Compared with some mainstream prediction models, the R2 value has increased, while both MAE and RMSE values have decreased, indicating its ability to accurately predict passenger flow in deep underground spaces. Full article
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<p>Hyperparametric optimization process.</p>
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<p>SSA vs. BWO optimization process.</p>
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<p>Improved two-layer LSTM structure.</p>
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<p>TCN-LSTM-Self-Attention network structure.</p>
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<p>Passenger traffic for 31 days at one location.</p>
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<p>Loss values for different models.</p>
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<p>Line graphs of the results of multiple model passenger flow forecasts.</p>
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<p>Line graphs of the results of multiple models’ passenger flow forecasts.</p>
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22 pages, 6936 KiB  
Article
Design and Performance Analysis of a Parallel Pipeline Robot
by Zhonghua Shen, Menglin Xie, Zhendong Song and Danyang Bao
Electronics 2024, 13(23), 4848; https://doi.org/10.3390/electronics13234848 - 9 Dec 2024
Viewed by 316
Abstract
A parallel four-legged pipeline robot is designed to mitigate the issue of uneven motor loading on the single-leg linkage responsible for movement along the pipe diameter. This issue occurs because the drive motor located closer to the robot body requires higher torque when [...] Read more.
A parallel four-legged pipeline robot is designed to mitigate the issue of uneven motor loading on the single-leg linkage responsible for movement along the pipe diameter. This issue occurs because the drive motor located closer to the robot body requires higher torque when the serial robot operates along the inner wall of a circular polyethylene gas pipe in an urban environment. The forward and inverse kinematic equations for a single-leg linkage are derived to establish the relationship between joint angles and foot trajectories. Building on this analysis, the forward and inverse kinematic solutions for all four legs are also derived. An optimized diagonal trotting gait is selected as the robot’s walking pattern to ensure a balance between stability and movement efficiency, considering the robot’s structural configuration. Motion simulations for both the serial and parallel robots are performed using simulation software, with a detailed analysis of the displacement of the robot’s center of mass and the leg centers during movement. The driving torque of the leg motors in both configurations is controlled and examined. Simulation results indicate that the designed parallel four-legged pipeline robot achieves lower motion error and smoother leg movements within the pipe. Compared to the serial robot, the maximum torque required to drive the leg motors is reduced by approximately 33%, demonstrating the effectiveness and validity of the overall structural design. Full article
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<p>Overall display.</p>
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<p>Motion structure diagram of parallel robot 1. 1—Hip joint drive motor, 2—Hip joint plate, 3—Hip joint linkage, 4—Second mobile joint drive motor, 5—Second mobile joint active linkage, 6—Second mobile joint passive linkage, 7—Sucker, 8—Sucker connecting member, 9—First mobile joint passive linkage, 10—First mobile joint active linkage, 11—First mobile joint drive motor, 12—Body part.</p>
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<p>Motion structure diagram of parallel robot 2.</p>
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<p>Initial position of parallel pipeline robot.</p>
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<p>Coordinate system of robot leg single chain.</p>
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<p>Plan–coordinate system of leg single chain.</p>
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<p>Plan–coordinate system of leg single chain 2.</p>
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<p>Four different gaits.</p>
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<p>Axial gait diagram.</p>
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<p>Sequence chart.</p>
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<p>Surface mesh generation.</p>
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<p>Initial state of the tandem and the parallel.</p>
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<p>Both the parallel type’s and tandem type’s moving joint of the LB.</p>
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<p>Both the parallel type’s and tandem type’s moving joint of the LF.</p>
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<p>The centroid displacement of the robot’s body part.</p>
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<p>Vertical displacement of legs.</p>
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<p>Both the parallel type’s and tandem type’s hip joint of the LB.</p>
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<p>Both the parallel type’s and tandem type’s moving joint of the LF.</p>
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<p>Both the parallel type’s and tandem type’s moving joint of the LB.</p>
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<p>The centroid displacement of the robot’s body part.</p>
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18 pages, 1071 KiB  
Article
PMHR: Path-Based Multi-Hop Reasoning Incorporating Rule-Enhanced Reinforcement Learning and KG Embeddings
by Ang Ma, Yanhua Yu, Chuan Shi, Shuai Zhen, Liang Pang and Tat-Seng Chua
Electronics 2024, 13(23), 4847; https://doi.org/10.3390/electronics13234847 - 9 Dec 2024
Viewed by 364
Abstract
Multi-hop reasoning provides a means for inferring indirect relationships and missing information from knowledge graphs (KGs). Reinforcement learning (RL) was recently employed for multi-hop reasoning. Although RL-based methods provide explainability, they face challenges such as sparse rewards, spurious paths, large action spaces, and [...] Read more.
Multi-hop reasoning provides a means for inferring indirect relationships and missing information from knowledge graphs (KGs). Reinforcement learning (RL) was recently employed for multi-hop reasoning. Although RL-based methods provide explainability, they face challenges such as sparse rewards, spurious paths, large action spaces, and long training and running times. In this study, we present a novel approach that combines KG embeddings and RL strategies for multi-hop reasoning called path-based multi-hop reasoning (PMHR). We address the issues of sparse rewards and spurious paths by incorporating a well-designed reward function that combines soft rewards with rule-based rewards. The rewards are adjusted based on the target entity and the path to it. Furthermore, we perform action filtering and utilize the vectors of entities and relations acquired through KG embeddings to initialize the environment, thereby significantly reducing the runtime. Experiments involving a comprehensive performance evaluation, efficiency analysis, ablation studies, and a case study were performed. The experimental results on benchmark datasets demonstrate the effectiveness of PMHR in improving KG reasoning accuracy while preserving interpretability. Compared to existing state-of-the-art models, PMHR achieved Hit@1 improvements of 0.63%, 2.02%, and 3.17% on the UMLS, Kinship, and NELL-995 datasets, respectively. PMHR provides not only improved reasoning accuracy and explainability but also optimized computational efficiency, thereby offering a robust solution for multi-hop reasoning. Full article
(This article belongs to the Special Issue Future Technologies for Data Management, Processing and Application)
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<p>An example of a KG. Solid edges are observed and the dashed edge is a query.</p>
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<p>An overview of PMHR model.</p>
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<p>The distribution of the shortest path lengths.</p>
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<p>The efficiency comparison between PMHR and path-based models.</p>
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<p>Ablation study on key parts of PMHR.</p>
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12 pages, 4219 KiB  
Article
Analysis of the Influence of Time Harmonics on the Leakage Coefficient of Canned Permanent Magnet Synchronous Motors
by Ming Li, Rong Wang, Lei Chi and Shuxian Lun
Electronics 2024, 13(23), 4846; https://doi.org/10.3390/electronics13234846 - 9 Dec 2024
Viewed by 292
Abstract
At present, the influence of time-harmonic currents on the leakage flux coefficient of canned permanent magnet synchronous motors (CPMSMs) remains unclear. Therefore, this paper investigates and summarizes the effects of inverter time-harmonic currents on the leakage flux coefficient of the CPMSM. A 1.5 [...] Read more.
At present, the influence of time-harmonic currents on the leakage flux coefficient of canned permanent magnet synchronous motors (CPMSMs) remains unclear. Therefore, this paper investigates and summarizes the effects of inverter time-harmonic currents on the leakage flux coefficient of the CPMSM. A 1.5 kW, 9000 RPM (Revolutions Per Minute) CPMSM is used as the research subject. Based on a finite element model, the leakage flux coefficients under sinusoidal and non-sinusoidal supply conditions are calculated using the magnetic flux density integration method. Additionally, the study examines changes in the leakage flux coefficient under different harmonic orders and amplitudes. The results indicate that the introduction of fifth and seventh time-harmonic currents by the inverter reduces the leakage flux coefficient, which helps to improve the utilization of the permanent magnets. This research significantly contributes to enriching the theory of inverter-fed permanent magnet motors. Full article
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<p>Two-dimensional finite element model of the CPMSM.</p>
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<p>Calculation model for the magnetic flux density by the integral method.</p>
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<p>A-phase winding current waveform.</p>
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<p>Magnetic flux density distribution under different excitations for CPMSM: (<b>a</b>) fundamental wave, (<b>b</b>) +5% of the fifth harmonic, and (<b>c</b>) +5% of the seventh harmonic.</p>
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<p>Air-gap magnetic flux density waveform and harmonic components of the CPMSM: (<b>a</b>) air-gap magnetic flux density waveform and (<b>b</b>) harmonic components of air-gap magnetic flux density.</p>
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<p>The effect of current time-harmonic orders on the magnetic flux and leakage flux coefficient of the motor.</p>
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<p>The leakage flux coefficient at various harmonic amplitudes.</p>
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<p>Unit motor model of 1.5 kW CPMSM.</p>
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<p>Prototype test platform: (<b>a</b>) motor performance testing system, (<b>b</b>) temperature-monitored inverter-powered motor testing.</p>
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<p>Prototype no-load back electromotive force waveform: (<b>a</b>) measured waveform, (<b>b</b>) simulation waves, (<b>c</b>) harmonic spectra.</p>
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28 pages, 5412 KiB  
Article
A Declarative Modeling Framework for Intuitive Multiple Criteria Decision Analysis in a Visual Semantic Urban Planning Environment
by Georgios Bardis
Electronics 2024, 13(23), 4845; https://doi.org/10.3390/electronics13234845 - 9 Dec 2024
Viewed by 319
Abstract
The magnitude and multiformity of recorded and readily available urban data from independent sensors and mobile user devices have paved new possibilities for city environment planning and evolution. In previous works, a visual semantic decision support system for urban planning was presented, and [...] Read more.
The magnitude and multiformity of recorded and readily available urban data from independent sensors and mobile user devices have paved new possibilities for city environment planning and evolution. In previous works, a visual semantic decision support system for urban planning was presented, and the capability of machine learning approaches, ranging from random forests to graph-based convolutional neural networks, to infer preferable directions for future development was explored, extrapolating upon previous opted locations and selected alternatives for publicly commercial services. In this work, the anterior decision-making process leading to establishment choices is addressed with the same sets of criteria and samples within the same environment. A Declarative Modeling shell is proposed, and Multiple Criteria Decision Analysis processes are adopted to encompass the DM’s/DMs’ rationale, solely relying on methodologies close to human intuition. To this end, outranking representatives from the PROMETHEE family as well as weighted sum approaches are employed, fueled by the interpretation of the declarative description of decision parameters on behalf of the DM(s), exploring the ability to achieve classifications in a straight synthetic manner, i.e., in the absence of previous knowledge, thus exhibiting the potential of decision analysis methodologies, enhanced by Declarative Modeling, to be used as powerful intuitive tools in similar paradigm contexts. Full article
(This article belongs to the Special Issue New Challenges of Decision Support Systems)
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<p>The Declarative Modeling methodology cycle.</p>
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<p>Graph of PROMETHEE I/II positive and negative outranking flows for problem with 4 alternatives.</p>
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<p>Normalized performance per feature of all top samples of PROMETHEE I and for top 15 samples of PROMETHEE II in all scenarios of Experiment 1.</p>
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<p>Graphical representation of sample 101 in visual urban planning environment.</p>
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<p>Normalized performance per feature of all top samples of PROMETHEE I and for top 10 samples of PROMETHEE II in all scenarios of Experiment 2.</p>
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17 pages, 1791 KiB  
Article
Apple Defect Detection in Complex Environments
by Wei Shan and Yurong Yue
Electronics 2024, 13(23), 4844; https://doi.org/10.3390/electronics13234844 - 9 Dec 2024
Viewed by 349
Abstract
Aiming at the problem of high false detection and missed detection rate of apple surface defects in complex environments, a new apple surface defect detection network: space-to-depth convolution-Multi-scale Empty Attention-Context Guided Feature Pyramid Network-You Only Look Once version 8 nano (SMC-YOLOv8n) is designed. [...] Read more.
Aiming at the problem of high false detection and missed detection rate of apple surface defects in complex environments, a new apple surface defect detection network: space-to-depth convolution-Multi-scale Empty Attention-Context Guided Feature Pyramid Network-You Only Look Once version 8 nano (SMC-YOLOv8n) is designed. Firstly, space-to-depth convolution (SPD-Conv) is introduced before each Faster Implementation of CSP Bottleneck with 2 convolutions (C2f) in the backbone network as a preprocessing step to improve the quality of input data. Secondly, the Bottleneck in C2f is removed in the neck, and Multi-scale Empty Attention (MSDA) is introduced to enhance the feature extraction ability. Finally, the Context Guided Feature Pyramid Network (CGFPN) is used to replace the Concat method of the neck for feature fusion, thereby improving the expression ability of the features. Compared with the YOLOv8n baseline network, mean Average Precision (mAP) 50 increased by 2.7% and 1.1%, respectively, and mAP50-95 increased by 4.1% and 2.7%, respectively, on the visible light apple surface defect data set and public data set in the self-made complex environments.The experimental results show that SMC-YOLOv8n shows higher efficiency in apple defect detection, which lays a solid foundation for intelligent picking and grading of apples. Full article
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<p>ADDCE research work classification.</p>
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<p>The overall architecture of YOLOv8.</p>
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<p>SPD-Conv structure diagram.</p>
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<p>C2f structure diagram.</p>
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<p>MSDA structure diagram.</p>
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<p>C2f-MSDA structure diagram.</p>
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<p>SE Attention module.</p>
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<p>SE Attention structure diagram.</p>
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<p>Context guide feature pyramid network architecture diagram.</p>
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<p>SMC-YOLOV8n.</p>
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<p>Examples of some data sets.</p>
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<p>Training curve and test curve.</p>
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<p>Test set confusion matrix.</p>
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<p>Part of the apple detection map.</p>
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23 pages, 4893 KiB  
Article
Enhancing Software Effort Estimation with Pre-Trained Word Embeddings: A Small-Dataset Solution for Accurate Story Point Prediction
by Issa Atoum and Ahmed Ali Otoom
Electronics 2024, 13(23), 4843; https://doi.org/10.3390/electronics13234843 - 8 Dec 2024
Viewed by 613
Abstract
Traditional software effort estimation methods, such as term frequency–inverse document frequency (TF-IDF), are widely used due to their simplicity and interpretability. However, they struggle with limited datasets, fail to capture intricate semantics, and suffer from dimensionality, sparsity, and computational inefficiency. This study used [...] Read more.
Traditional software effort estimation methods, such as term frequency–inverse document frequency (TF-IDF), are widely used due to their simplicity and interpretability. However, they struggle with limited datasets, fail to capture intricate semantics, and suffer from dimensionality, sparsity, and computational inefficiency. This study used pre-trained word embeddings, including FastText and GPT-2, to improve estimation accuracy in such cases. Seven pre-trained models were evaluated for their ability to effectively represent textual data, addressing the fundamental limitations of TF-IDF through contextualized embeddings. The results show that combining FastText embeddings with support vector machines (SVMs) consistently outperforms traditional approaches, reducing the mean absolute error (MAE) by 5–18% while achieving accuracy comparable to deep learning models like GPT-2. This approach demonstrated the adaptability of pre-trained embeddings for small datasets, balancing semantic richness with computational efficiency. The proposed method optimized project planning and resource allocation while enhancing software development through accurate story point prediction while safeguarding privacy and security through data anonymization. Future research will explore task-specific embeddings tailored to software engineering domains and investigate how dataset characteristics, such as cultural variations, influence model performance, ensuring the development of adaptable, robust, and secure machine learning models for diverse contexts. Full article
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<p>Proposed methodology.</p>
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<p>Average MAE for pre-trained models across vector lengths (50–700). Lower values indicate better model performance, with FastText and SBERT achieving the lowest MAE.</p>
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<p>Average MAE for pre-trained models across vector lengths (50–700). Lower values indicate better model performance, with FastText and SBERT achieving the lowest MAE.</p>
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<p>Average RMSE for pre-trained models across vector lengths. Lower values indicate better model performance, with FastText and SBERT achieving the lowest RMSE.</p>
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<p>Average MMRE for pre-trained models across vector lengths (50–700). Lower values indicate better model performance, with FastText and SBERT achieving the lowest.</p>
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<p>Average MMRE for pre-trained models across vector lengths (50–700). Lower values indicate better model performance, with FastText and SBERT achieving the lowest.</p>
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<p>Average PRED (25) scores for pre-trained models. SBERT and USE achieved the highest percentage of predictions.</p>
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<p>Average PRED (25) scores for pre-trained models. SBERT and USE achieved the highest percentage of predictions.</p>
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<p>Percentage improvement in MAE for pre-trained models compared to TF-IDF. FastText showed the highest improvement, particularly at a vector length of 700.</p>
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<p>Percentage improvement in MMRE for pre-trained models compared to TF-IDF. FastText consistently outperformed TF-IDF, demonstrating significant improvements.</p>
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<p>Percentage of improvement in RMSE for pre-trained models compared to TF-IDF. FastText demonstrated the highest improvement, underscoring its stability and reliability.</p>
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21 pages, 759 KiB  
Article
Optimizing Privacy in Set-Valued Data: Comparing Certainty Penalty and Information Gain
by Soonseok Kim
Electronics 2024, 13(23), 4842; https://doi.org/10.3390/electronics13234842 - 8 Dec 2024
Viewed by 516
Abstract
The increase in set-valued data such as transaction records and medical histories has introduced new challenges in data anonymization. Traditional anonymization techniques targeting structured microdata comprising single-attribute- rather than set-valued records are often insufficient to ensure privacy protection in complex datasets, particularly when [...] Read more.
The increase in set-valued data such as transaction records and medical histories has introduced new challenges in data anonymization. Traditional anonymization techniques targeting structured microdata comprising single-attribute- rather than set-valued records are often insufficient to ensure privacy protection in complex datasets, particularly when re-identification attacks leverage partial background knowledge. To address these limitations, this study proposed the Local Generalization and Reallocation (LGR) + algorithm to replace the Normalized Certainty Penalty loss measure (hereafter, NCP) used in traditional LGR algorithms with the Information Gain Heuristic metric (hereafter, IGH). IGH, an entropy-based metric, evaluates information loss based on uncertainty and provides users with the advantage of balancing privacy protection and data utility. For instance, when IGH causes greater information-scale data annotation loss than NCP, it ensures stronger privacy protection for datasets that contain sensitive or high-risk information. Conversely, when IGH induces less information loss, it provides better data utility for less sensitive or low-risk datasets. The experimental results based on using the BMS-WebView-2 and BMS-POS datasets showed that the IGH-based LGR + algorithm caused up to 100 times greater information loss than NCP, indicating significantly improved privacy protection. Although the opposite case also exists, the use of IGH introduces the issue of increased computational complexity. Future research will focus on optimizing efficiency through parallel processing and sampling techniques. Ultimately, LGR+ provides the only viable solution for improving the balance between data utility and privacy protection, particularly in scenarios that prioritize strong privacy or utility guarantees. Full article
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<p>Example of NCP-based anonymization for the original dataset (when {<span class="html-italic">a</span><sub>1</sub>, <span class="html-italic">a</span><sub>2</sub>} are generalized to <span class="html-italic">A</span>).</p>
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<p>Comparison of information loss between the BMS-WebView-2 and BMS-POS datasets using the NCP and IGH metrics under different <span class="html-italic">k</span>-anonymity values.</p>
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31 pages, 19634 KiB  
Article
Particle Swarm Optimization for k-Coverage and 1-Connectivity in Wireless Sensor Networks
by Georgios Siamantas and Dionisis Kandris
Electronics 2024, 13(23), 4841; https://doi.org/10.3390/electronics13234841 - 8 Dec 2024
Viewed by 334
Abstract
Wireless Sensor Networks are used in an ever-increasing range of applications, thanks to their ability to monitor and transmit data related to ambient conditions in almost any area of interest. The optimization of coverage and the assurance of connectivity are fundamental for the [...] Read more.
Wireless Sensor Networks are used in an ever-increasing range of applications, thanks to their ability to monitor and transmit data related to ambient conditions in almost any area of interest. The optimization of coverage and the assurance of connectivity are fundamental for the efficiency and consistency of Wireless Sensor Networks. Optimal coverage guarantees that all points in the field of interest are monitored, while the assurance of the connectivity of the network nodes assures that the gathered data are reliably transferred among the nodes and the base station. In this research article, a novel algorithm based on Particle Swarm Optimization is proposed to ensure coverage and connectivity in Wireless Sensor Networks. The objective function is derived from energy function minimization methodologies commonly applied in bounded space circle packing problems. The performance of the novel algorithm is not only evaluated through both simulation and statistical tests that demonstrate the efficacy of the proposed methodology but also compared against that of relative algorithms. Finally, concluding remarks are drawn on the potential extensibility and actual use of the algorithm in real-world scenarios. Full article
(This article belongs to the Special Issue Recent Advances in Wireless Ad Hoc and Sensor Networks)
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<p>Architecture of a typical WSN.</p>
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<p><span class="html-italic">k</span>-coverage sensor point geometry.</p>
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<p>Calculation example of two sensor nodes communication ranges (dashed lines) based on their sensing ranges (solid lines) where the letters denote the locations of these sensor nodes: (<b>a</b>) case where both sensing ranges = 3 and both communication ranges = 6; (<b>b</b>) case where sensing ranges = 2 and 3, and both communication ranges = 5.</p>
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<p>Case study 1: optimal node locations.</p>
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<p>Case study 1: optimal node locations with 1-connectivity.</p>
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<p>Case study 1: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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<p>Case study 2: optimal node locations.</p>
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<p>Case study 2: optimal node locations with 1-connectivity.</p>
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<p>Case study 2: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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<p>Case study 3: optimal node locations.</p>
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<p>Case study 3: optimal node locations with 1-connectivity.</p>
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<p>Case study 3: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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<p>Case study 4: optimal node locations.</p>
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<p>Case study 4: optimal node locations with 1-connectivity.</p>
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<p>Case study 4: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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<p>Case study 5: optimal node locations.</p>
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<p>Case study 5: optimal node locations with 1-connectivity.</p>
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<p>Case study 5: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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<p>Case study 6: optimal node locations.</p>
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<p>Case study 6: optimal node locations with 1-connectivity.</p>
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<p>Case study 6: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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<p>Case study 7: optimal node locations.</p>
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<p>Case study 7: optimal node locations with 1-connectivity.</p>
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<p>Case study 7: objective function iterations: (<b>a</b>) no connectivity; (<b>b</b>) 1-connectivity.</p>
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15 pages, 1523 KiB  
Article
Efficient Neural Network-Based Compact Modeling for Novel Device Structures Using a Multi-Fidelity Model and Active Learning
by HyunJoon Jeong, JinYoung Choi, Yohan Kim, Jeong-Taek Kong and SoYoung Kim
Electronics 2024, 13(23), 4840; https://doi.org/10.3390/electronics13234840 - 8 Dec 2024
Viewed by 451
Abstract
Neural network (NN)-based compact modeling methodologies are gaining attention due to the challenges of device complexity, narrow model coverage, and SPICE simulation speed in advanced semiconductor technology nodes. As device complexity increases, the number of process and structural variables also increases, which significantly [...] Read more.
Neural network (NN)-based compact modeling methodologies are gaining attention due to the challenges of device complexity, narrow model coverage, and SPICE simulation speed in advanced semiconductor technology nodes. As device complexity increases, the number of process and structural variables also increases, which significantly increases the amount of technology computer-aided design (TCAD) simulation data required for NN-based compact modeling. This study proposes a multi-fidelity model and active learning approach to predict global and local variations of nanosheet FETs (NSFETs) with less than 1.5% error, significantly reducing the number of required TCAD simulations by more than half compared with conventional modeling techniques. In addition, the simplified NN model with a smaller training dataset significantly reduces the SPICE simulation time. Full article
(This article belongs to the Special Issue Advanced CMOS Devices and Applications, 2nd Edition)
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<p>An example of the LFNN model, HF model (Golden), and MFNN model for conceptual illustration.</p>
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<p>An example comparing Latin hypercube sampling and active learning for conceptual illustration.</p>
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<p>(<b>a</b>) The NSFET <span class="html-italic">Y</span>-axis section, (<b>b</b>) <span class="html-italic">X</span>-axis section, (<b>c</b>) the 3D structure with work function variation (WFV) applied to gate metal, and (<b>d</b>) the 3D structure with random dopant fluctuation (RDF).</p>
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<p>Calibrated I-V curves with measurement data [<a href="#B15-electronics-13-04840" class="html-bibr">15</a>].</p>
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<p>The structure of the ANN model.</p>
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<p>The proposed MFNN-based compact model with active learning.</p>
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<p>The test loss of the MFNN model according to predicted and actual weights.</p>
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<p>Decay plots for the test loss of the MFNN model with and without transfer learning using the LFNN model.</p>
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<p>Decay plots for the test loss in ANN with LHS, ANN with active learning, MFNN with LHS, and our work, with 40 data points being added sequentially for (<b>a</b>) NMOS and (<b>b</b>) PMOS.</p>
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<p>Implementation of the ANN-based compact model as a SPICE model using the Verilog-A language.</p>
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<p>Fitting results (<span class="html-italic">I</span>−<span class="html-italic">V</span>: ∼1.5% error, <span class="html-italic">C</span>−<span class="html-italic">V</span>: ∼1% error) of the proposed MFNN-based compact model for four devices randomly selected from the unseen 100-test dataset (<b>a</b>) <math display="inline"><semantics> <msub> <mi>I</mi> <mrow> <mi>d</mi> <mi>s</mi> </mrow> </msub> </semantics></math>−<math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>g</mi> <mi>s</mi> </mrow> </msub> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <msub> <mi>I</mi> <mrow> <mi>d</mi> <mi>s</mi> </mrow> </msub> </semantics></math>−<math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>s</mi> </mrow> </msub> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <msub> <mi>g</mi> <mi>m</mi> </msub> </semantics></math>−<math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>g</mi> <mi>s</mi> </mrow> </msub> </semantics></math>, (<b>d</b>) <span class="html-italic">C</span>−<span class="html-italic">V</span> (<math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>s</mi> </mrow> </msub> </semantics></math> = 0.05 V), and (<b>e</b>) <span class="html-italic">C</span>−<span class="html-italic">V</span> (<math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>s</mi> </mrow> </msub> </semantics></math> = 0.65 V).</p>
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<p>The Gummel symmetry test results of the MFNN-based compact model. (The results for <math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>g</mi> <mi>s</mi> </mrow> </msub> </semantics></math> = 0 V and <math display="inline"><semantics> <msub> <mi>V</mi> <mrow> <mi>g</mi> <mi>s</mi> </mrow> </msub> </semantics></math> = 0.15 V are overlapped.)</p>
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<p>The scatter plots of RO delay at average accuracy levels of (<b>a</b>) 95%, (<b>b</b>) 97%, and (<b>c</b>) 98.5%, and the number of TCAD simulations (NMOS) required to achieve these accuracy levels.</p>
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<p>(<b>a</b>) The required MFNN model size according to the number of TCAD simulations (NMOS); (<b>b</b>) SPICE simulation speed according to the model size for 10,000 Monte Carlo simulations of a 9-stage RO.</p>
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12 pages, 2538 KiB  
Article
A Fault Diagnosis Method for Turnout Switch Machines Based on Sound Signals
by Yong Li, Xinyi Tao and Yongkui Sun
Electronics 2024, 13(23), 4839; https://doi.org/10.3390/electronics13234839 - 7 Dec 2024
Viewed by 399
Abstract
The turnout switch machine, a vital outdoor component of railway signaling, controls train steering amidst complex operations and high frequencies. Its malfunction significantly disrupts train operations, potentially causing derailments. This paper proposes a sound-based fault diagnosis method, termed ERS (a method combining EMD, [...] Read more.
The turnout switch machine, a vital outdoor component of railway signaling, controls train steering amidst complex operations and high frequencies. Its malfunction significantly disrupts train operations, potentially causing derailments. This paper proposes a sound-based fault diagnosis method, termed ERS (a method combining EMD, ReliefF, and SVM), for effective monitoring and detection of turnout switch machines. The method employs Eigenmode Decomposition (EMD) to smooth the sound signal, reduce noise, and extract key statistical parameters of both the time and frequency domains. To address redundant information in high-dimensional features, the ReliefF algorithm is utilized for feature selection, dimension reduction, and fault classification based on weighted parameters. Subsequently, the selected feature parameters are used to train the Support Vector Machine (SVM). A comparison with results obtained without ReliefF feature selection demonstrates the necessity of this step. The results show that the fault diagnosis accuracy reaches 98% in the positioning work mode and 95.67% in the reversing work mode, verifying the method’s effectiveness and feasibility. Full article
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<p>Execution process of ERS.</p>
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<p>Internal view of the turnout switch machine.</p>
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<p>Ten types of time domain waveforms in the positioning work. Note that the x-coordinate of all figures denotes the time (s).</p>
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<p>The first 16 IMFs of Type A sound signals.</p>
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<p>Confusion matrix (CM) for full-feature testing. Noted: Red numbers denote the accuracy, and the depth of color in the picture indicates the magnitude of the value. (<b>a</b>) Positioning work mode; (<b>b</b>) reversing work mode.</p>
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<p>Confusion matrix (CM) for dimensionality reduction feature testing. Noted: Red numbers denote the accuracy, and the depth of color in the picture indicates the magnitude of the value. (<b>a</b>) Positioning work mode; (<b>b</b>) reversing work mode.</p>
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16 pages, 4458 KiB  
Article
High-Performance Garbage Collection Scheme with Low Data Transfer Overhead for NoC-Based SSDC
by Seyeon Ahn, Donghyuk Im, Donggon You and Youpyo Hong
Electronics 2024, 13(23), 4838; https://doi.org/10.3390/electronics13234838 - 7 Dec 2024
Viewed by 392
Abstract
Solid-state drives (SSDs) have become the preferred storage solution for performance-critical applications due to their high speed, durability, and energy efficiency. However, the inherent characteristics of NAND flash memory, such as block-level erasure and data fragmentation, necessitate frequent garbage collection (GC) operations to [...] Read more.
Solid-state drives (SSDs) have become the preferred storage solution for performance-critical applications due to their high speed, durability, and energy efficiency. However, the inherent characteristics of NAND flash memory, such as block-level erasure and data fragmentation, necessitate frequent garbage collection (GC) operations to reclaim storage space. These operations, while essential, introduce significant performance overhead, particularly in modern SSD controllers (SSDCs) that utilize network-on-chip (NoC) architectures. In such architectures, GC requires substantial data transfer over interconnects for error correction, leading to increased latency and reduced throughput. This paper presents a novel GC scheme designed to minimize latency in NoC-based SSDCs. Unlike conventional methods that unconditionally transfer data for error correction, the proposed approach selectively determines the data transfer path based on the presence of errors. By leveraging the low error probability of NAND flash memory, this scheme avoids unnecessary data traversal across the interconnect, significantly reducing GC overhead. A hardware implementation using task queues ensures efficient parallelism without disrupting other operations. The experimental results demonstrate that the proposed scheme improves SSD performance across various real-world workloads, achieving up to a 26.9% reduction in average latency and a 50.0% reduction in peak latency compared to traditional GC methods. These findings highlight the potential of optimizing data traversal paths in NoC architectures, providing a scalable solution for enhancing SSD performance for diverse applications. Full article
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<p>Conventional SSD organization (FMC: flash memory controller).</p>
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<p>Illustration of garbage collection in SSD.</p>
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<p>NoC-style SSD controller architecture.</p>
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<p>Copy-back data path selection by the proposed GC scheme.</p>
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<p>Configuration of dual task queue.</p>
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<p>Host request patterns.</p>
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<p>Host request patterns.</p>
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<p>Number of host requests, GC requests, and pending requests.</p>
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<p>Number of host requests, GC requests, and pending requests.</p>
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<p>Number of copy-backs.</p>
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<p>Read and write request patterns of Cassandra.</p>
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12 pages, 3245 KiB  
Article
GDE-Pose: A Real-Time Adaptive Compression and Multi-Scale Dynamic Feature Fusion Approach for Pose Estimation
by Kaiian Kuok, Xuan Liu, Jinwei Ye, Yaokang Wang and Wenjian Liu
Electronics 2024, 13(23), 4837; https://doi.org/10.3390/electronics13234837 - 7 Dec 2024
Viewed by 386
Abstract
This paper introduces a novel lightweight pose estimation model, GDE-pose, which addresses the current trade-off between accuracy and computational efficiency in existing models. GDE-pose builds upon the baseline YOLO-pose model by incorporating Ghost Bottleneck, a Dynamic Feature Fusion Module (DFFM), and ECA Attention [...] Read more.
This paper introduces a novel lightweight pose estimation model, GDE-pose, which addresses the current trade-off between accuracy and computational efficiency in existing models. GDE-pose builds upon the baseline YOLO-pose model by incorporating Ghost Bottleneck, a Dynamic Feature Fusion Module (DFFM), and ECA Attention to achieve more effective feature representation and selection. The Ghost Bottleneck reduces computational complexity, DFFM enhances multi-scale feature fusion, and ECA Attention optimizes the selection of key features. GDE-pose improves pose estimation accuracy while preserving real-time performance. Experimental results demonstrate that GDE-pose achieves higher accuracy on the COCO dataset, with a substantial reduction in parameters, over 80% fewer FLOPs, and an increased inference speed of 31 FPS, underscoring its exceptional lightweight and real-time capabilities. Ablation studies confirm the independent contribution of each module to the model’s overall performance. GDE-pose’s design highlights its broad applicability in real-time pose estimation tasks. Full article
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<p>Overall architecture of GDE-pose.</p>
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<p>(<b>a</b>) C3k2_Ghost (<b>b</b>) C3k2_DFFM.</p>
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<p>Diagram of C3k2_DFFM.</p>
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<p>Illustration of GDE-pose performance.</p>
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<p>Illustration of loss results.</p>
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17 pages, 3917 KiB  
Article
SincNet-Based Speaker Identification for Robotic Environments with Varying Human–Robot Interaction Distance
by Seo-Hyun Kim, A-Hyeon Jo and Keun-Chang Kwak
Electronics 2024, 13(23), 4836; https://doi.org/10.3390/electronics13234836 - 7 Dec 2024
Viewed by 383
Abstract
As human–robot interaction (HRI) becomes increasingly significant, various studies have focused on speaker recognition. However, few studies have explored this topic in the specific environment of home service robots. Notably, most existing research relies on databases composed of English-language data, while studies utilizing [...] Read more.
As human–robot interaction (HRI) becomes increasingly significant, various studies have focused on speaker recognition. However, few studies have explored this topic in the specific environment of home service robots. Notably, most existing research relies on databases composed of English-language data, while studies utilizing Korean speech data are exceedingly scarce. This gap underscores the need for research on speaker recognition in robotic environments, specifically using Korean data. In response, this paper conducts experiments using a speaker recognition database tailored to the Korean language and set in a robotic context. The database includes noise generated by robot movement as well as common environmental noise, accounting for variable distances between humans and robots, which are partitioned accordingly. The deep learning model employed is SincNet, with experiments conducted under two settings for the SincNet filter parameters: one with learnable parameters and the other with fixed values. After training the model with data collected at varying distances, performance was tested across these distances. Experimental results indicate that SincNet with learnable parameters achieved a peak accuracy of 99%. Full article
(This article belongs to the Special Issue Control and Applications of Intelligent Robotic System)
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<p>Speaker identification and testing procedure using data acquired in a robotic environment.</p>
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<p>Speech data after applying the Sinc filters to the raw data.</p>
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<p>Hamming window size for each sample.</p>
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<p>Structure of SincNet.</p>
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<p>Data preprocessing and speaker identification.</p>
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<p>Comparison of model accuracy when training on data captured at distances of (<b>a</b>) 1 m, (<b>b</b>) 2 m, and (<b>c</b>) 3 m.</p>
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<p>Comparison of model accuracy when training on data captured at distances of (<b>a</b>) 1 m, (<b>b</b>) 2 m, and (<b>c</b>) 3 m.</p>
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<p>Changes in the starting frequency of the Sinc filter (<b>a</b>) before and (<b>b</b>) after training.</p>
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<p>Changes in the bandwidth of the Sinc filter (<b>a</b>) before and (<b>b</b>) after training.</p>
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<p>ROC curves for the SincNet trained on data captured at a distance of 3 m and tested on data acquired at distances of (<b>a</b>) 1 m, (<b>b</b>) 2 m, and (<b>c</b>) 3 m.</p>
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<p>ROC curves for the SincNet trained on data captured at a distance of 3 m and tested on data acquired at distances of (<b>a</b>) 1 m, (<b>b</b>) 2 m, and (<b>c</b>) 3 m.</p>
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<p>Comparison of ROC curves: SincNet, Constant SincNet, and RawNet.</p>
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23 pages, 696 KiB  
Article
KG-EGV: A Framework for Question Answering with Integrated Knowledge Graphs and Large Language Models
by Kun Hou, Jingyuan Li, Yingying Liu, Shiqi Sun, Haoliang Zhang and Haiyang Jiang
Electronics 2024, 13(23), 4835; https://doi.org/10.3390/electronics13234835 - 7 Dec 2024
Viewed by 456
Abstract
Despite the remarkable progress of large language models (LLMs) in understanding and generating unstructured text, their application in structured data domains and their multi-role capabilities remain underexplored. In particular, utilizing LLMs to perform complex reasoning tasks on knowledge graphs (KGs) is still an [...] Read more.
Despite the remarkable progress of large language models (LLMs) in understanding and generating unstructured text, their application in structured data domains and their multi-role capabilities remain underexplored. In particular, utilizing LLMs to perform complex reasoning tasks on knowledge graphs (KGs) is still an emerging area with limited research. To address this gap, we propose KG-EGV, a versatile framework leveraging LLMs to perform KG-based tasks. KG-EGV consists of four core steps: sentence segmentation, graph retrieval, EGV, and backward updating, each designed to segment sentences, retrieve relevant KG components, and derive logical conclusions. EGV, a novel integrated framework for LLM inference, enables comprehensive reasoning beyond retrieval by synthesizing diverse evidence, which is often unattainable via retrieval alone due to noise or hallucinations. The framework incorporates six key stages: generation expansion, expansion evaluation, document re-ranking, re-ranking evaluation, answer generation, and answer verification. Within this framework, LLMs take on various roles, such as generator, re-ranker, evaluator, and verifier, collaboratively enhancing answer precision and logical coherence. By combining the strengths of retrieval-based and generation-based evidence, KG-EGV achieves greater flexibility and accuracy in evidence gathering and answer formulation. Extensive experiments on widely used benchmarks, including FactKG, MetaQA, NQ, WebQ, and TriviaQA, demonstrate that KG-EGV achieves state-of-the-art performance in answer accuracy and evidence quality, showcasing its potential to advance QA research and applications. Full article
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<p>Illustration of the multi-role capabilities in the KG-EGV framework. KG-EGV incorporates multiple roles within large language models (LLMs) to perform generation, re-ranking, evaluation, and verification.</p>
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<p>Overview of the KG-EGV framework for knowledge graph-based question answering and fact verification. KG-EGV operates in six steps: (1) sentence segmentation, (2) graph retrieval, (3) query expansion and generation, (4) re-ranking and evaluation, (5) answer generation, and (6) answer verification with dynamic updates.</p>
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<p>Diagram illustrating the integration of knowledge graphs (KGs) and large language models (LLMs) in the KG-EGV framework for question answering (QA) tasks.</p>
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<p>Bar chart comparing the performance of various methods (KG-EGV, ToG, SearChain, KG-GPT, and CoT) across tasks (FactKG, MetaQA, and WebQA).</p>
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<p>Line chart illustrating the dynamic knowledge graph update process. The number of new triples added increases with the number of trials, demonstrating the framework’s ability to incrementally augment the knowledge graph. All new triples were manually validated for correctness, achieving a 100% accuracy rate.</p>
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25 pages, 1778 KiB  
Article
Efficient User Pairing and Resource Optimization for NOMA-OMA Switching Enabled Dynamic Urban Vehicular Networks
by Aravindh Balaraman, Shigeo Shioda, Yonggang Kim, Yohan Kim and Taewoon Kim
Electronics 2024, 13(23), 4834; https://doi.org/10.3390/electronics13234834 - 7 Dec 2024
Viewed by 404
Abstract
Vehicular communication is revolutionizing transportation by enhancing passenger experience and improving safety through seamless message exchanges with nearby vehicles and roadside units (RSUs). To accommodate the growing number of vehicles in dense urban traffic with limited channel availability, non-orthogonal multiple access (NOMA) is [...] Read more.
Vehicular communication is revolutionizing transportation by enhancing passenger experience and improving safety through seamless message exchanges with nearby vehicles and roadside units (RSUs). To accommodate the growing number of vehicles in dense urban traffic with limited channel availability, non-orthogonal multiple access (NOMA) is a promising solution due to its ability to improve spectral efficiency by sharing channels among multiple users. However, to completely leverage NOMA on mobile vehicular networks, a chain of operations and resources must be optimized, including vehicle user (VU) and RSU association, channel assignment, and optimal power control. In contrast, traditional orthogonal multiple access (OMA) allocates separate channels to users, simplifying management but falling short in high-density environments. Additionally, enabling NOMA-OMA switching can further enhance the system performance while significantly increasing the complexity of the optimization task. In this study, we propose an optimized framework to jointly utilize the power domain NOMA in a vehicular network, where dynamic NOMA-OMA switching is enabled, by integrating the optimization of vehicle-to-RSU association, channel assignment, NOMA-OMA switching, and transmit power allocation into a single solution. To handle the complexity of these operations, we also propose simplified formulations that make the solution practical for real-time applications. The proposed framework reduces total power consumption by up to 27% compared to Util&LB/opt, improves fairness in user association by 18%, and operates efficiently with minimal computational overhead. These findings highlight the potential of the proposed framework to enhance communication performance in dynamic, densely populated urban environments. Full article
(This article belongs to the Special Issue Wireless Sensor Network: Latest Advances and Prospects)
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<p>Assumed power domain NOMA system where a vehicular user receives downlink service from its associated roadside unit with dynamic NOMA-OMA switching and resource optimization.</p>
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<p>Flowchart of the proposed approach that consists of two phases to jointly optimize association, channel assignment, NOMA-OMA switching and transmit power allocation.</p>
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<p>An example urban intersection road scenario with five RSUs and twenty vehicle users denoted by black circles and red triangles, respectively.</p>
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<p>Mean total power consumption for a simple and stationary configuration with a single channel with respect to the number of VUs on the network.</p>
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<p>Mean association fairness performance for a simple, stationary configuration with a single channel with respect to the number of VUs on the network.</p>
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<p>Mean proportion of the NOMA channels for a simple, stationary configuration with a single channel with respect to the number of VUs on the network.</p>
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<p>Mean total power consumption for a complex, stationary configuration with twenty VUs and three channels.</p>
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<p>Mean association fairness performance for a complex, stationary configuration with twenty VUs and three channels.</p>
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<p>Mean proportion of the NOMA channels for a complex, stationary configuration with twenty VUs and three channels.</p>
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<p>Accumulated total power consumption for a long-term complex, mobile configuration with twenty VUs and three channels where each time step spans 100 ms.</p>
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<p>Comparison of the time taken to solve the considered problems with varying numbers of vehicular users on a single-channel stationary configuration.</p>
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<p>Comparison of the time taken to solve the considered problems with twenty users on a three-channel mobile and stationary configuration.</p>
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15 pages, 3698 KiB  
Article
Multichannel Wavelet Kernel Network for High Dimensional Inverse Modeling of Microwave Filters
by Di Zhang, Min Zhou, Zhiyu Wang and Hua Chen
Electronics 2024, 13(23), 4833; https://doi.org/10.3390/electronics13234833 - 7 Dec 2024
Viewed by 389
Abstract
This paper proposes a multichannel wavelet kernel network (MWKN) modeling technique with a two-stage training technique for high-dimensional inverse modeling of microwave filters. The real and imaginary parts of the transmission and reflection characteristics are used as the model inputs, while the geometric [...] Read more.
This paper proposes a multichannel wavelet kernel network (MWKN) modeling technique with a two-stage training technique for high-dimensional inverse modeling of microwave filters. The real and imaginary parts of the transmission and reflection characteristics are used as the model inputs, while the geometric parameters of the filter are designated as the outputs. Since the electrical signal in microwave inverse modeling encompasses multiple frequency components and complex information arising from the subtle dimensional changes in the metal pattern, the wavelet transform is introduced by leveraging its powerful multi-scale and approximate detail features to form the discrete wavelet convolution layer in the proposed MWKN. To adapt to the learning of approximate detailed features at different scales, the learnable parameters of this layer and the weights of the backbone network are adjusted in stages through a two-stage training strategy based on particle swarm optimization (PSO), which jointly promotes the rapid convergence of the model. Three numerical examples demonstrate the effectiveness and robustness of the proposed MWKN model. Compared with the traditional design method using electromagnetic (EM) simulation, this approach significantly and substantially reduces the repeated calculation time and is capable of predicting the geometry that meets the design specifications within 0.42 s. Full article
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<p>Decomposition procedure for the DWT.</p>
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<p>Structure of the proposed MWKN model.</p>
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<p>Flowchart of the proposed two-stage training strategy.</p>
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<p>The geometry structure of the parallel coupled line filter as the first example.</p>
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<p>S11 and S21 of the parallel coupled line filter as the first example: (<b>a</b>) S11; (<b>b</b>) S21.</p>
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<p>The geometry structure of the interdigital filter as the second example.</p>
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<p>S11 and S21 of the interdigital filter as the second example: (<b>a</b>) S11; (<b>b</b>) S21.</p>
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<p>The geometry structure of the waveguide filter as the third example.</p>
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<p>S11 and S21 of the waveguide filter as the third example: (<b>a</b>) S11; (<b>b</b>) S21.</p>
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<p>(<b>a</b>) Fabricated filter. (<b>b</b>) The S-parameter curves obtained from the HFSS simulation and the measurements.</p>
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18 pages, 5670 KiB  
Article
An All-Digital Dual-Mode Clock and Data Recovery Circuit for Human Body Communication Systems
by Yoon Heo and Won-Young Lee
Electronics 2024, 13(23), 4832; https://doi.org/10.3390/electronics13234832 - 7 Dec 2024
Viewed by 429
Abstract
This paper describes an all-digital clock and data recovery (CDR) circuit for implementing edge processing with a wireless body area network (WBAN). The CDR circuit performs delay-locked loop (DLL)-based and phase-locked loop (PLL)-based operations depending on the use of an external reference clock [...] Read more.
This paper describes an all-digital clock and data recovery (CDR) circuit for implementing edge processing with a wireless body area network (WBAN). The CDR circuit performs delay-locked loop (DLL)-based and phase-locked loop (PLL)-based operations depending on the use of an external reference clock and is implemented using a digital method that is robust against external noise. The clock generator circuit shared by the two operation methods is described in detail, and the CDR circuit recovers 42 Mb/s input data and a 42 MHz clock, which are the specifications of human body communication (HBC). In DLL-based CDR operation, the clock generator operates as a digitally controlled delay line (DCDL) that delays the reference clock by more than one period. In PLL-based CDR operations, it operates as a digitally controlled oscillator (DCO) that oscillates the 42 MHz clock and adjusts the clock frequency. The proposed all-digital CDR is fabricated in 65 nm CMOS technology with an area of 0.091 mm2 and operates with a supply voltage of 1.0 V. Post-layout simulation results show that the lock time for DLL-based CDR operation is 1.6 μs, the clock peak-to-peak jitter is 0.38 ns, and the power consumption is 341.8 μW. For PLL-based CDR operations, the lock time is 6 μs, the clock peak-to-peak jitter is 2.92 ns, and the power consumption is 280.2 μW, respectively. Full article
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<p>(<b>a</b>) PSD of FSDT modulated date. (<b>b</b>) Transceiver with FDST modulation for human body communication.</p>
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<p>Proposed all-digital CDR block diagram.</p>
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<p>Schematic of a conventional BBPD.</p>
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<p>Timing diagrams of (<b>a</b>) phase error and (<b>b</b>) frequency error detections.</p>
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<p>Schematic of a binary PFD.</p>
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<p>(<b>a</b>) Block diagram of a clock generator; (<b>b</b>) LDU connection structure of the coarse and fine delay unit; (<b>c</b>) schematic of a conventional LDU; (<b>d</b>) schematic of the proposed LDU.</p>
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<p>(<b>a</b>) Block diagram of a clock generator; (<b>b</b>) LDU connection structure of the coarse and fine delay unit; (<b>c</b>) schematic of a conventional LDU; (<b>d</b>) schematic of the proposed LDU.</p>
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<p>Timing diagrams of a 2-bit delay unit with (<b>a</b>) a conventional LDU and (<b>b</b>) the proposed LDU.</p>
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<p>Timing diagrams of a 2-bit delay unit with (<b>a</b>) a conventional LDU and (<b>b</b>) the proposed LDU.</p>
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<p>Block diagrams of (<b>a</b>) a proportional delay unit and (<b>b</b>) a proportional gain controller.</p>
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<p>Block diagram of (<b>a</b>) a digital loop filter and (<b>b</b>) a lock detector.</p>
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<p>Layout of the proposed CDR circuit.</p>
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<p>Post-layout simulation results of (<b>a</b>) DCDL delay and (<b>b</b>) DCO frequency.</p>
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<p>Waveforms of LDU output clocks with and without the proposed LDU structure.</p>
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<p>Post-layout Monte Carlo simulation of the 1-bit resolution of the LDUs and the inverter delay generating T<sub>n</sub>_bar.</p>
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<p>Loop locking operations of (<b>a</b>) the PLL-based CDR circuit and (<b>b</b>) the DLL-based CDR circuit.</p>
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<p>Loop locking operations of (<b>a</b>) the PLL-based CDR circuit and (<b>b</b>) the DLL-based CDR circuit.</p>
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<p>(<b>a</b>) Frequency acquisition results with and without PDU operation. (<b>b</b>) Frequency control range according to PDU gain.</p>
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<p>(<b>a</b>) Frequency acquisition results with and without PDU operation. (<b>b</b>) Frequency control range according to PDU gain.</p>
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<p>Post-layout simulation results of (<b>a</b>) recovered clock and (<b>b</b>) data of the DLL-based CDR circuit and (<b>c</b>) recovered clock and (<b>d</b>) data of the PLL-based CDR circuit.</p>
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<p>Results of (<b>a</b>) peak-to-peak jitter of recovered clock and (<b>b</b>) jitter tolerance.</p>
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<p>(<b>a</b>) Power breakdown of the DLL-based CDR circuit. (<b>b</b>) Power breakdown of the PLL-based CDR circuit.</p>
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12 pages, 3096 KiB  
Article
Digital Twin-Based Smart Feeding System Design for Machine Tools
by Baris Yuce, Haobing Li, Linlin Wang and Voicu Ion Sucala
Electronics 2024, 13(23), 4831; https://doi.org/10.3390/electronics13234831 - 6 Dec 2024
Viewed by 484
Abstract
With the continuous development of intelligent manufacturing technology, the application of intelligent feed systems in modern machine tools is becoming increasingly widespread. Digital twin technology achieves the monitoring and optimization of the entire life cycle of a physical system by constructing a virtual [...] Read more.
With the continuous development of intelligent manufacturing technology, the application of intelligent feed systems in modern machine tools is becoming increasingly widespread. Digital twin technology achieves the monitoring and optimization of the entire life cycle of a physical system by constructing a virtual image of the system, while neural network controllers, with their powerful nonlinear fitting ability, can accurately capture and simulate the dynamic behavior of complex systems, providing strong support for the optimization control of intelligent feed systems. This article discusses the design and implementation of an intelligent feed system based on digital twins and neural network controllers. Firstly, this article establishes a mathematical model based on the traditional ball screw structure and analyzes the dynamic characteristics and operating mechanism of the system. Subsequently, the mathematical model is fitted using a neural network controller to improve control accuracy and system response speed. The experimental results demonstrate that the neural network controller shows good consistency in fitting traditional mathematical models, not only effectively capturing the nonlinear characteristics of the system but also maintaining stable control performance under complex operating conditions. Full article
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<p>Proposed system structure.</p>
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<p>Implementation method of neural networks in an MES.</p>
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<p>Relationship between wear loss and wear time.</p>
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<p>Micro-element analysis for the shaft.</p>
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<p>General model for simulation.</p>
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<p>Sub-system describing the shaft.</p>
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<p>System building workflow.</p>
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<p>Topology architecture of proposed neural network.</p>
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<p>Temporal response of neural networks under low-frequency signals.</p>
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<p>Regression of neural network dataset.</p>
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24 pages, 5497 KiB  
Article
Finding All Solutions with Grover’s Algorithm by Integrating Estimation and Discovery
by Sihyung Lee and Seung Yeob Nam
Electronics 2024, 13(23), 4830; https://doi.org/10.3390/electronics13234830 - 6 Dec 2024
Viewed by 381
Abstract
Grover’s algorithm leverages quantum computing to efficiently locate solutions in unstructured search spaces, outperforming classical approaches. Since Grover’s algorithm requires prior knowledge of the number of solutions (M) within a search space of size N, previous studies assume M is [...] Read more.
Grover’s algorithm leverages quantum computing to efficiently locate solutions in unstructured search spaces, outperforming classical approaches. Since Grover’s algorithm requires prior knowledge of the number of solutions (M) within a search space of size N, previous studies assume M is estimated beforehand and focus on identifying all solutions. Here, we propose a two-step process that integrates both the estimation of M and the discovery of the solutions, optimizing the interactions between the two steps. To enhance efficiency, the estimation step captures as many solutions as possible, leaving the discovery step to focus on the remaining ones. To ensure accuracy, the discovery step continues searching until the probability of finding additional solutions becomes sufficiently low. We implemented and evaluated our methods, showing that over 80% of solutions were found during the estimation phase, allowing the discovery phase to conclude earlier, while identifying over 99% of solutions on average. In theory, the process requires NM × log(M) Grover’s iterations in the worst case, but in practice, it typically terminates after iterations proportional to N. We expect that our methods will be applicable to various search problems and inspire further research on efficiently finding all solutions. Full article
(This article belongs to the Section Computer Science & Engineering)
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<p>Overview of Grover’s algorithm.</p>
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<p>Example of Grover’s iterator process for <span class="html-italic">N</span> = 8 and target item ‘100’.</p>
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<p>Example of Grover’s iterator process for <span class="html-italic">N</span> = 8 and target item ‘100’.</p>
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<p>Overview of proposed methods.</p>
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<p>Implementation of Quantum Counting.</p>
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<p>Scatter plot of estimated values of <span class="html-italic">M</span> for <span class="html-italic">N</span> = 2<sup>9</sup>.</p>
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<p>Average number of solutions found by our method and the previous method for <span class="html-italic">N</span> = 512.</p>
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<p>Average number of Grover’s iterations used by our method and the previous method for <span class="html-italic">N</span> = 512.</p>
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<p>Number of solutions found in Steps 1 and 2 for <span class="html-italic">N</span> = 1024 and <span class="html-italic">M</span> = 32.</p>
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<p>Expected proportion of distinct solutions found in Step 1 of the proposed algorithm for <span class="html-italic">N</span> ranging from 2<sup>10</sup> to 2<sup>20</sup> and <span class="html-italic">j</span> ranging from 1 to 5.</p>
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35 pages, 6215 KiB  
Article
MIVNDN: Ultra-Short-Term Wind Power Prediction Method with MSDBO-ICEEMDAN-VMD-Nons-DCTransformer Net
by Qingze Zhuang, Lu Gao, Fei Zhang, Xiaoying Ren, Ling Qin and Yongping Wang
Electronics 2024, 13(23), 4829; https://doi.org/10.3390/electronics13234829 - 6 Dec 2024
Viewed by 434
Abstract
Wind speed, wind direction, humidity, temperature, altitude, and other factors affect wind power generation, and the uncertainty and instability of the above factors bring challenges to the regulation and control of wind power generation, which requires flexible management and scheduling strategies. Therefore, it [...] Read more.
Wind speed, wind direction, humidity, temperature, altitude, and other factors affect wind power generation, and the uncertainty and instability of the above factors bring challenges to the regulation and control of wind power generation, which requires flexible management and scheduling strategies. Therefore, it is crucial to improve the accuracy of ultra-short-term wind power prediction. To solve this problem, this paper proposes an ultra-short-term wind power prediction method with MIVNDN. Firstly, the Spearman’s and Kendall’s correlation coefficients are integrated to select the appropriate features. Secondly, the multi-strategy dung beetle optimization algorithm (MSDBO) is used to optimize the parameter combinations in the improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) method, and the optimized decomposition method is used to decompose the historical wind power sequence to obtain a series of intrinsic modal function (IMF) components with different frequency ranges. Then, the high-frequency band IMF components and low-frequency band IMF components are reconstructed using the t-mean test and sample entropy, and the reconstructed high-frequency IMF component is decomposed quadratically using the variational modal decomposition (VMD) to obtain a new set of IMF components. Finally, the Nons-Transformer model is improved by adding dilated causal convolution to its encoder, and the new set of IMF components, as well as the unreconstructed mid-frequency band IMF components and the reconstructed low-frequency IMF, component are used as inputs to the model to obtain the prediction results and perform error analysis. The experimental results show that our proposed model outperforms other single and combined models. Full article
(This article belongs to the Section Artificial Intelligence)
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<p>(<b>a</b>) Frequency value. (<b>b</b>) Frequency mapping.</p>
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<p>MSDBO process.</p>
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<p>Nons-Transformer process.</p>
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<p>Nons-DCTransformer process.</p>
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<p>MSDBO-ICEEMDAN-VMD-Nons-DCTransformer process.</p>
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<p>Historical wind power data.</p>
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<p>(<b>a</b>) Spearman’s correlation coefficient; (<b>b</b>) Kendall’s correlation coefficient.</p>
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<p>Comparison of optimization algorithms.</p>
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<p>MSDBO-ICEEMDAN primary decomposition spectrum results.</p>
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<p>Sample entropy results.</p>
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<p>VMD quadratic decomposition spectrum.</p>
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<p>Radar chart of evaluation indicators reconstructed by secondary decomposition.</p>
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<p>(<b>a</b>) Single-model evaluation metrics; (<b>b</b>) combined model evaluation metrics.</p>
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<p>Benchmark model comparison.</p>
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<p>(<b>a</b>) Single-model comparison; (<b>b</b>) combined model comparison.</p>
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<p>Comparative test MAE.</p>
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<p>Dramatic fluctuations in historical wind power sequence.</p>
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<p>More stable historical wind power sequence.</p>
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<p>(<b>a</b>) Single model; (<b>b</b>) combined model.</p>
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<p>(<b>a</b>) Single model; (<b>b</b>) combined model.</p>
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13 pages, 1482 KiB  
Article
Novel Low-Power Computing-In-Memory (CIM) Design for Binary and Ternary Deep Neural Networks by Using 8T XNOR SRAM
by Achyuth Gundrapally, Nader Alnatsheh and Kyuwon Ken Choi
Electronics 2024, 13(23), 4828; https://doi.org/10.3390/electronics13234828 - 6 Dec 2024
Viewed by 372
Abstract
The increasing demand for high-performance and low-power hardware in artificial intelligence (AI) applications, such as speech recognition, facial recognition, and object detection, has driven the exploration of advanced memory designs. Convolutional neural networks (CNNs) and deep neural networks (DNNs) require intensive computational resources, [...] Read more.
The increasing demand for high-performance and low-power hardware in artificial intelligence (AI) applications, such as speech recognition, facial recognition, and object detection, has driven the exploration of advanced memory designs. Convolutional neural networks (CNNs) and deep neural networks (DNNs) require intensive computational resources, leading to memory access times and power consumption challenges. To address these challenges, we propose the application of computing-in-memory (CIM) within FinFET-based 8T SRAM structures, specifically utilizing P-latch N-access (PLNA) and single-ended (SE) configurations. Our design significantly reduces power consumption by up to 56% in the PLNA configuration and 60% in the SEconfiguration compared to traditional FinFET SRAM designs. These reductions are achieved while maintaining competitive delay performance, making our approach a promising solution for implementing efficient and low-power AI hardware. Detailed simulations in 7 nm FinFET technology underscore the potential of these CIM-based SRAM structures in overcoming the computational bottlenecks associated with DNNs and CNNs. Full article
(This article belongs to the Special Issue Recent Advances in AI Hardware Design)
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<p>Comparison between von Neumann and computing-in-memory(CIM) architecture.</p>
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<p>Ternary XNOR operation with fixed weights and varying inputs. Subfigures (<b>a</b>–<b>d</b>) explains different XNOR inputs and desired outputs.</p>
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<p>P-Latch N-Access (PLNA) SRAM structure with XNOR logic.</p>
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<p>Single-Ended (SE) SRAM structure with XNOR logic.</p>
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<p>Original SRAM waveform analysis of the proposed XNOR-SRAM CIM operation for ternary inputs. The input signals (+1, 0, −1, +0) are represented by yellow, black, cyan, and magenta lines, respectively. The ternary combination output (−1, 0, +1) is shown by the orange line. The complementary output Qb is indicated by the green line, while the primary output Q is represented by the blue line. The results illustrate correct ternary computation, highlighting the functionality of the XNOR pass transistor logic.</p>
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<p>PLNA SRAM waveform analysis of the proposed XNOR-SRAM CIM operation for ternary inputs. The input signals (+1, 0, −1, +0) are represented by yellow, black, cyan, and magenta lines, respectively. The ternary combination output (−1, 0, +1) is shown by the orange line. The complementary output Qb is indicated by the green line, while the primary output Q is represented by the blue line. The results illustrate correct ternary computation, highlighting the functionality of the XNOR pass transistor logic.</p>
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<p>SE SRAM waveform analysis of the proposed XNOR-SRAM CIM operation for ternary inputs. The input signals (+1, 0, −1, +0) are represented by yellow, black, cyan, and magenta lines, respectively. The ternary combination output (−1, 0, +1) is shown by the orange line. The complementary output Qb is indicated by the green line, while the primary output Q is represented by the blue line. The results illustrate correct ternary computation, highlighting the functionality of the XNOR pass transistor logic.</p>
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23 pages, 1948 KiB  
Article
PerFuSIT: Personalized Fuzzy Logic Strategies for Intelligent Tutoring of Programming
by Konstantina Chrysafiadi and Maria Virvou
Electronics 2024, 13(23), 4827; https://doi.org/10.3390/electronics13234827 - 6 Dec 2024
Viewed by 365
Abstract
Recent advancements in intelligent tutoring systems (ITS) driven by artificial intelligence (AI) have attracted substantial research interest, particularly in the domain of computer programming education. Given the diversity in learners’ backgrounds, cognitive abilities, and learning paces, the development of personalized tutoring strategies to [...] Read more.
Recent advancements in intelligent tutoring systems (ITS) driven by artificial intelligence (AI) have attracted substantial research interest, particularly in the domain of computer programming education. Given the diversity in learners’ backgrounds, cognitive abilities, and learning paces, the development of personalized tutoring strategies to support the effective attainment of learning objectives has become a critical challenge. This paper introduces personalized fuzzy logic strategies for intelligent programming tutoring (PerFuSIT), an innovative fuzzy logic-based module designed to select the most appropriate tutoring strategy from five available options, based on individual learner characteristics. The available strategies include revisiting previous content, progressing to the next topic, providing supplementary materials, assigning additional exercises, or advising the learner to take a break. PerFuSIT’s decision-making process incorporates a range of learner-specific parameters, such as performance metrics, error types, indicators of carelessness, frequency of help requests, and the time required to complete tasks. Embedded within the traditional ITS framework, PerFuSIT introduces a sophisticated reasoning mechanism for dynamically determining the optimal instructional approach. Experimental evaluations demonstrate that PerFuSIT significantly enhances learner performance and improves the overall efficacy of interactions with the ITS. The findings highlight the potential of fuzzy logic to optimize adaptive tutoring strategies by customizing instruction to individual learners’ strengths and weaknesses, thereby providing more effective and personalized educational support in programming instruction. Full article
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<p>ITS that incorporates PerFuSIT.</p>
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<p>Architecture of PerFuSIT.</p>
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<p>Fuzzy sets for tutoring strategy significance.</p>
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<p>Fuzzy sets for input variables of PerFuSIT.</p>
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