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Technologies
Volume 11
Issue 2
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Technologies, Volume 11, Issue 2 (April 2023) – 30 articles

Cover Story (view full-size image): Both the human eye and a digital camera sense both light intensity and color. We use visual information for various purposes, including seeing things, keeping our physical balance, and making judgments based on one's situational experiences. It naturally becomes subjective and uncertain. The quantification of color from digital images, including prints and static/dynamic digital data, is necessary to reduce uncertainty and subjectivity for quantified data-driven judgments and control applications in various fields. This study shows reliable, image-based quantification of color using specially developed image processing and analysis software. This image-based quantification software (PicMan) is useful for a wide range of applications in art, fashion, medical science, and many other fields. View this paper
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17 pages, 2067 KiB  
Article
Geographical Dependence of Open Hardware Optimization: Case Study of Solar Photovoltaic Racking
by Shafquat Rana, Nicholas Vandewetering, Jadyn Powell, Jonathan Álvarez Ariza and Joshua M. Pearce
Technologies 2023, 11(2), 62; https://doi.org/10.3390/technologies11020062 - 21 Apr 2023
Cited by 3 | Viewed by 2632
Abstract
Open-source technological development is well-known for rapid innovation and providing opportunities to reduce costs and thus increase accessibility for a wide range of products. This is done through distributed manufacturing, in which products are produced close to end users. There is anecdotal evidence [...] Read more.
Open-source technological development is well-known for rapid innovation and providing opportunities to reduce costs and thus increase accessibility for a wide range of products. This is done through distributed manufacturing, in which products are produced close to end users. There is anecdotal evidence that these opportunities are heavily geographically dependent, with some locations unable to acquire components to build open hardware at accessible prices because of trade restrictions, tariffs, taxes, or market availability. Supply chain disruptions during the COVID-19 pandemic exacerbated this and forced designers to pivot towards a la carte-style design frameworks for critical system components. To further develop this phenomenon, a case study of free and open-source solar photovoltaic (PV) racking systems is provided. Two similar open-source designs made from different materials are compared in terms of capital costs for their detailed bill of materials throughout ten locations in North, Central and South America. The differences in economic optimization showed that the costs of wood-based racks were superior in North America and in some South American countries, while metal was less costly in Central and South America. The results make it clear that open hardware designs would be best to allow for local optimization based on material availability in all designs. Full article
(This article belongs to the Collection Electrical Technologies)
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21 pages, 5074 KiB  
Article
An Improved Photovoltaic Module Array Global Maximum Power Tracker Combining a Genetic Algorithm and Ant Colony Optimization
by Kuo-Hua Huang, Kuei-Hsiang Chao and Ting-Wei Lee
Technologies 2023, 11(2), 61; https://doi.org/10.3390/technologies11020061 - 20 Apr 2023
Cited by 5 | Viewed by 1581
Abstract
In this paper, a hybrid optimization controller that combines a genetic algorithm (GA) and ant colony optimization (ACO) called GA-ACO algorithm is proposed. It is applied to a photovoltaic module array (PVMA) to carry out maximum power point tracking (MPPT). This way, under [...] Read more.
In this paper, a hybrid optimization controller that combines a genetic algorithm (GA) and ant colony optimization (ACO) called GA-ACO algorithm is proposed. It is applied to a photovoltaic module array (PVMA) to carry out maximum power point tracking (MPPT). This way, under the condition that the PVMA is partially shaded and that multiple peaks are produced in the power-voltage (P-V) characteristic curve, the system can still operate at the global maximum power point (GMPP). This solves the problem seen in general traditional MPPT controllers where the PVMA works at the local maximum power point (LMPP). The improved MPPT controller that combines GA and ACO uses the slope of the P-V characteristic curve at the PVMA work point to dynamically adjust the iteration parameters of ACO. The simulation results prove that the improved GA-ACO MPPT controller is able to quickly track GMPP when the output P-V characteristic curve of PVMA shows the phenomenon of multiple peaks. Comparing the time required for tracking to MPP with different MPPT approaches for the PVMA under five different shading levels, it was observed that the improved GA-ACO algorithm requires 19.5~35.9% (average 29.2%) fewer iterations to complete tracking than the mentioned GA-ACO algorithm. Compared with the ACO algorithm, it requires 74.9~79.7% (average 78.2%) fewer iterations, and 75.0~92.5% (average 81.0%) fewer than the conventional P&O method. Therefore, it is proved that by selecting properly adjusted values of the Pheromone evaporation rate and the Gaussian standard deviation of the proposed GA-ACO algorithm based on the slope scope of the P-V characteristic curves, a better response performance of MPPT is obtained. Full article
(This article belongs to the Topic Advances in Solar Technologies)
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11 pages, 1896 KiB  
Communication
Research on Outdoor Mobile Music Speaker Battery Management Algorithm Based on Dynamic Redundancy
by Xiaofei Yu, Yanke Li, Xiaonan Li, Licheng Wang and Kai Wang
Technologies 2023, 11(2), 60; https://doi.org/10.3390/technologies11020060 - 18 Apr 2023
Cited by 19 | Viewed by 1633
Abstract
In terms of the battery management system of a mobile music speaker, reliability optimization has always been an important topic. This paper proposes a new dynamic redundant battery management algorithm based on the existing fault-tolerant structure of a lithium battery pack. The internal [...] Read more.
In terms of the battery management system of a mobile music speaker, reliability optimization has always been an important topic. This paper proposes a new dynamic redundant battery management algorithm based on the existing fault-tolerant structure of a lithium battery pack. The internal configuration is adjusted according to the SOC of each battery, and the power supply battery is dynamically allocated. This paper selects four batteries to experiment on with two different algorithms. The simulation results show that compared with the traditional battery management algorithm, the dynamic redundant battery management algorithm extends the battery pack working time by 18.75%, and the energy utilization rate of B1 and B4 increases by 96.0% and 99.8%, respectively. This proves that the dynamic redundant battery management algorithm can effectively extend battery working time and improve energy utilization. Full article
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14 pages, 2433 KiB  
Article
Photovoltaic Inverter Reliability Study through SiC Switches Redundant Structures
by Ignacio Villanueva, Nimrod Vázquez, Joaquín Vaquero, Claudia Hernández, Héctor López-Tapia and Rene Osorio-Sánchez
Technologies 2023, 11(2), 59; https://doi.org/10.3390/technologies11020059 - 14 Apr 2023
Cited by 2 | Viewed by 1640
Abstract
Reliability is a very important issue in power electronics; however, sometimes it is not considered, studied, or analyzed. At present, renewables have become more popular, and more complex setups are required to drive this type of system. In the specific case of inverters [...] Read more.
Reliability is a very important issue in power electronics; however, sometimes it is not considered, studied, or analyzed. At present, renewables have become more popular, and more complex setups are required to drive this type of system. In the specific case of inverters in photovoltaic systems, the user’s safety, quality, reliability, and the system’s useful life must be guaranteed. In this paper, the reliability of a full bridge inverter is predicted by calculating metrics such as failure rates and Mean Time Between Failures. Reliability is obtained using different types of structures for SiC MOSFETs: serial systems, active parallel redundant systems, and passive parallel redundant systems. Finally, the reliability study shows that a system with a passive parallel redundant structure is more reliable and has a higher useful life compared to the other structures. Full article
(This article belongs to the Collection Electrical Technologies)
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16 pages, 3584 KiB  
Article
Computational Investigation of a Tibial Implant Using Topology Optimization and Finite Element Analysis
by Nikolaos Kladovasilakis, Theologos Bountourelis, Konstantinos Tsongas and Dimitrios Tzetzis
Technologies 2023, 11(2), 58; https://doi.org/10.3390/technologies11020058 - 13 Apr 2023
Cited by 1 | Viewed by 1780
Abstract
Additive manufacturing methods enable the rapid fabrication of fully functional customized objects with complex geometry and lift the limitations of traditional manufacturing techniques, such as machining. Therefore, the structural optimization of parts has concentrated increased scientific interest and more especially for topology optimization [...] Read more.
Additive manufacturing methods enable the rapid fabrication of fully functional customized objects with complex geometry and lift the limitations of traditional manufacturing techniques, such as machining. Therefore, the structural optimization of parts has concentrated increased scientific interest and more especially for topology optimization (TO) processes. In this paper, the working principles and the two approaches of the TO procedures were analyzed along with an investigation and a comparative study of a novel case study for the TO processes of a tibial implant designed for additive manufacturing (DfAM). In detail, the case study focused on the TO of a tibial implant for knee replacement surgery in order to improve the overall design and enhance its efficiency and the rehabilitation process. An initial design of a customized tibial implant was developed utilizing reserve engineering procedures with DICOM files from a CT scan machine. The mechanical performance of the designed implant was examined via finite element analyses (FEA) under realistic static loads. The TO was conducted with two distinct approaches, namely density-based and discrete-based, to compare them and lead to the best approach for biomechanical applications. The overall performance of each approach was evaluated through FEA, and its contribution to the final mass reduction was measured. Through this study, the maximum reduction in the implant’s mass was achieved by maintaining the mechanical performance at the desired levels and the best approach was pointed out. To conclude, with the discrete-based approach, a mass reduction of around 45% was achieved, almost double of the density-based approach, offering on the part physical properties which provide comprehensive advantages for biomechanical application. Full article
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13 pages, 2670 KiB  
Article
Possibilities of Using Bluetooth Low Energy Beacon Technology to Locate Objects Internally: A Case Study
by Jan Ližbetin and Jan Pečman
Technologies 2023, 11(2), 57; https://doi.org/10.3390/technologies11020057 - 12 Apr 2023
Cited by 3 | Viewed by 2401
Abstract
The developments that are occurring in relation to Industry 4.0 are making it possible to automate a huge number of production activities. Automation includes the possibility of automatically identifying individual elements of a system. One of the options for doing this involves the [...] Read more.
The developments that are occurring in relation to Industry 4.0 are making it possible to automate a huge number of production activities. Automation includes the possibility of automatically identifying individual elements of a system. One of the options for doing this involves the use of Bluetooth Low Energy technology. The system’s advantages lie in its wide availability, economic simplicity, ability to design individual system elements, and overall system architecture. The system applied in the case study presented in this article consisted of beacons from Accent Systems and identification gateways based on the Raspberry Pi Zero W device. During several hours of testing, the functionality and reliability of all system components was demonstrated. The measurements showed that the system was able to determine the distance from a gate in line of sight with 94% accuracy. With regards to indirect visibility, when a metal crate was used to shield the beacon from the gateway, the system was able to determine the exact distance only 22% of the time. However, the variance between the actual and measured values was found to be small, therefore proving sufficient for most use cases. The major advantage of Bluetooth Low Energy beacons, and Bluetooth technology in general, is its massive ubiquity in the market. Since the Bluetooth module is part of every smartphone, this system can be made available to a wide range of users. Full article
(This article belongs to the Section Information and Communication Technologies)
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11 pages, 5968 KiB  
Communication
Examination of Polymer Blends by AFM Phase Images
by Enrico Werner, Uwe Güth, Bennet Brockhagen, Christoph Döpke and Andrea Ehrmann
Technologies 2023, 11(2), 56; https://doi.org/10.3390/technologies11020056 - 12 Apr 2023
Cited by 3 | Viewed by 2711
Abstract
Atomic force microscopy (AFM) belongs to the high-resolution surface morphology investigation methods. Since it can, in many cases, be applied in air, samples can more easily be inspected than by a scanning electron microscope (SEM). In addition, several special modes exist which enable [...] Read more.
Atomic force microscopy (AFM) belongs to the high-resolution surface morphology investigation methods. Since it can, in many cases, be applied in air, samples can more easily be inspected than by a scanning electron microscope (SEM). In addition, several special modes exist which enable examination of the mechanical and other physical parameters of the specimen, such as friction, adhesion between tip and sample, elastic modulus, etc. In tapping mode, e.g., phase imaging can be used to qualitatively distinguish between different materials on the surface. This is especially interesting for polymers, for which the evaluation by energy-dispersive X-ray spectroscopy (EDS) is mostly irrelevant. Here we give an overview of phase imaging experiments on different filaments used for 3D printing by fused deposition modeling (FDM). Furthermore, the acrylonitrile butadiene styrene (ABS), especially different poly(lactide acids) (PLAs) with special features, such as thermochromic or photochromic properties, are investigated and compared with SEM images. Full article
(This article belongs to the Topic Smart Manufacturing and Industry 5.0)
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17 pages, 1314 KiB  
Article
A Novel Methodology for Human Kinematics Motion Detection Based on Smartphones Sensor Data Using Artificial Intelligence
by Ali Raza, Mohammad Rustom Al Nasar, Essam Said Hanandeh, Raed Abu Zitar, Ahmad Yacoub Nasereddin and Laith Abualigah
Technologies 2023, 11(2), 55; https://doi.org/10.3390/technologies11020055 - 11 Apr 2023
Cited by 8 | Viewed by 2986
Abstract
Kinematic motion detection aims to determine a person’s actions based on activity data. Human kinematic motion detection has many valuable applications in health care, such as health monitoring, preventing obesity, virtual reality, daily life monitoring, assisting workers during industry manufacturing, caring for the [...] Read more.
Kinematic motion detection aims to determine a person’s actions based on activity data. Human kinematic motion detection has many valuable applications in health care, such as health monitoring, preventing obesity, virtual reality, daily life monitoring, assisting workers during industry manufacturing, caring for the elderly. Computer vision-based activity recognition is challenging due to problems such as partial occlusion, background clutter, appearance, lighting, viewpoint, and changes in scale. Our research aims to detect human kinematic motions such as walking or running using smartphones’ sensor data within a high-performance framework. An existing dataset based on smartphones’ gyroscope and accelerometer sensor values is utilized for the experiments in our study. Sensor exploratory data analysis was conducted in order to identify valuable patterns and insights from sensor values. The six hyperparameters, tunned artificial indigence-based machine learning, and deep learning techniques were applied for comparison. Extensive experimentation showed that the ensemble learning-based novel ERD (ensemble random forest decision tree) method outperformed other state-of-the-art studies with high-performance accuracy scores. The proposed ERD method combines the random forest and decision tree models, which achieved a 99% classification accuracy score. The proposed method was successfully validated with the k-fold cross-validation approach. Full article
(This article belongs to the Special Issue Wearable Technologies III)
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4 pages, 451 KiB  
Editorial
Medical Imaging and Image Processing
by Yudong Zhang and Zhengchao Dong
Technologies 2023, 11(2), 54; https://doi.org/10.3390/technologies11020054 - 05 Apr 2023
Cited by 5 | Viewed by 4528
Abstract
Medical imaging (MI) [...] Full article
(This article belongs to the Special Issue Medical Imaging & Image Processing III)
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15 pages, 1994 KiB  
Article
Visual Performance and Perceptual–Motor Skills of Late Preterm Children and Healthy Controls Using the TVPS-3rd and VMI-6th Editions
by Danjela Ibrahimi, Jorge D. Mendiola Santibañez and Juvenal Rodríguez-Reséndiz
Technologies 2023, 11(2), 53; https://doi.org/10.3390/technologies11020053 - 04 Apr 2023
Cited by 1 | Viewed by 2088
Abstract
Background: The visual system is key to the learning process, preterm births are commonly followed by visual dysfunctions and other neurological conditions. Objective: to measure, analyze and compare the visual efficacy, visual–perceptual, and visual–motor skills of 20 late preterm children (34–36 weeks) born [...] Read more.
Background: The visual system is key to the learning process, preterm births are commonly followed by visual dysfunctions and other neurological conditions. Objective: to measure, analyze and compare the visual efficacy, visual–perceptual, and visual–motor skills of 20 late preterm children (34–36 weeks) born by caesarean section and appropriate weight for gestational age with 20 healthy controls born at full term by natural birth, age 5 to 12 years, from Querétaro, México. Methods: This was an observational, transverse, and prospective study. Parametric and non-parametric tests were performed using the SPSS 25.0. The visual acuity at distance and near, the phoria state, and the degree of stereopsis were analyzed. The Test of Visual-Perceptual Skills, Third Edition, was used to assess the overall performance, basic, sequencing, and complex processes. Fine motor skills were evaluated using the Visual–Motor Integration Test of Beery, Sixth Edition. Results: Visual acuity at distance and near (p<0.001), stereopsis (p<0.001), and the amount of exophoria at distance (p=0.01) showed statistically significant differences between the groups. The overall performance (p=0.006), basic processes (p=0.001), sequencing processes (p=0.02), and General and Motor VMI (p<0.001 and 0.002, respectively) presented lower values in children born preterm. Conclusion: This research showed that even late preterm children present visual deficiencies and are at risk of delays on perceptual–motor skills. Early evaluation of their visual and motor abilities should be considered in order to help improve their cognitive functioning. Full article
(This article belongs to the Special Issue Smart Systems (SmaSys2022))
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10 pages, 4431 KiB  
Communication
Anisotropy Analysis of the Permeation Behavior in Carbon Dioxide-Assisted Polymer Compression Porous Products
by Takafumi Aizawa
Technologies 2023, 11(2), 52; https://doi.org/10.3390/technologies11020052 - 03 Apr 2023
Viewed by 1241
Abstract
The carbon dioxide-assisted polymer compression method is used to create porous polymer products with laminated fiber sheets that are crimped in the presence of carbon dioxide. In this method, fibers are oriented in the sheet-spread direction, and the intersections of the upper and [...] Read more.
The carbon dioxide-assisted polymer compression method is used to create porous polymer products with laminated fiber sheets that are crimped in the presence of carbon dioxide. In this method, fibers are oriented in the sheet-spread direction, and the intersections of the upper and lower fibers are crimped, leading to several intersections within the porous product. This type of orientation in a porous material is anisotropic. A dye solution was injected via a syringe into a compression product made of poly(ethylene terephthalate) nonwoven fabric with an average fiber diameter of 8 μm. The anisotropy of permeation was evaluated using the aspect ratio of the vertical and horizontal permeation distances of a permeation area. The aspect ratio decreased monotonically with decreasing porosity; it was 2.73 for the 80-ply laminated product with a porosity of 0.63 and 2.33 for the 160-ply laminated product with a porosity of 0.25. A three-dimensional structural analysis using X-ray computed tomography revealed that as the compression ratio increased, the fiber-to-fiber connection increased due to the increase in adhesion points, resulting in decreased anisotropy of permeation. The anisotropy of permeation is essential data for analyzing the sustained release behavior of drug-loaded tablets for future fabrication. Full article
(This article belongs to the Special Issue Advanced Processing Technologies of Innovative Materials)
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11 pages, 4140 KiB  
Communication
HAIS: Highways Automated-Inspection System
by Hossam A. Gabbar, Abderrazak Chahid, Manir U. Isham, Shashwat Grover, Karan Pal Singh, Khalid Elgazzar, Ahmad Mousa and Hossameldin Ouda
Technologies 2023, 11(2), 51; https://doi.org/10.3390/technologies11020051 - 01 Apr 2023
Cited by 3 | Viewed by 2084
Abstract
A smart city is a trending concept describing a new generation of cities operated intelligently with minimal human intervention. It promotes energy sustainability, minimal environmental impact, and better governance. In transportation, the remote highway infrastructure monitoring will enhance the driver’s safety, continuously report [...] Read more.
A smart city is a trending concept describing a new generation of cities operated intelligently with minimal human intervention. It promotes energy sustainability, minimal environmental impact, and better governance. In transportation, the remote highway infrastructure monitoring will enhance the driver’s safety, continuously report road conditions, and identify potential hazardous incidents such as accidents, floods, or snow storms. In addition, it facilitates the integration of future cuttingedge technologies such as self-driving vehicles. This paper presents a general introduction to a smart monitoring system for automated real-time road condition inspection. The proposed solution includes hardware devices/nodes and software applications for data processing, road condition inspection using hybrid algorithms based on digital signal processing, and artificial intelligence technologies. The proposed system has an interactive web interface for real-time data sharing, infrastructure monitoring, visualization, and management of inspection reports which can improve the maintenance process. Full article
(This article belongs to the Topic Emerging Technologies for Grid-Interactive Efficient Buildings and Communities)
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18 pages, 1984 KiB  
Article
Forecasting by Combining Chaotic PSO and Automated LSSVR
by Wei-Chang Yeh and Wenbo Zhu
Technologies 2023, 11(2), 50; https://doi.org/10.3390/technologies11020050 - 30 Mar 2023
Cited by 1 | Viewed by 1188
Abstract
An automatic least square support vector regression (LSSVR) optimization method that uses mixed kernel chaotic particle swarm optimization (CPSO) to handle regression issues has been provided. The LSSVR model is composed of three components. The position of the particles (solution) in a chaotic [...] Read more.
An automatic least square support vector regression (LSSVR) optimization method that uses mixed kernel chaotic particle swarm optimization (CPSO) to handle regression issues has been provided. The LSSVR model is composed of three components. The position of the particles (solution) in a chaotic sequence with good randomness and ergodicity of the initial characteristics is taken into consideration in the first section. The binary particle swarm optimization (PSO) used to choose potential input characteristic combinations makes up the second section. The final step involves using a chaotic search to narrow down the set of potential input characteristics before combining the PSO-optimized parameters to create CP-LSSVR. The CP-LSSVR is used to forecast the impressive datasets testing targets obtained from the UCI dataset for purposes of illustration and evaluation. The results suggest CP-LSSVR has a good predictive capability discussed in this paper and can build a projected model utilizing a limited number of characteristics. Full article
(This article belongs to the Special Issue 10th Anniversary of Technologies—Recent Advances and Perspectives)
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19 pages, 11909 KiB  
Article
Image-Based Quantification of Color and Its Machine Vision and Offline Applications
by Woo Sik Yoo, Kitaek Kang, Jung Gon Kim and Yeongsik Yoo
Technologies 2023, 11(2), 49; https://doi.org/10.3390/technologies11020049 - 29 Mar 2023
Cited by 2 | Viewed by 2661
Abstract
Image-based colorimetry has been gaining relevance due to the wide availability of smart phones with image sensors and increasing computational power. The low cost and portable designs with user-friendly interfaces, and their compatibility with data acquisition and processing, are very attractive for interdisciplinary [...] Read more.
Image-based colorimetry has been gaining relevance due to the wide availability of smart phones with image sensors and increasing computational power. The low cost and portable designs with user-friendly interfaces, and their compatibility with data acquisition and processing, are very attractive for interdisciplinary applications from art, the fashion industry, food science, medical science, oriental medicine, agriculture, geology, chemistry, biology, material science, environmental engineering, and many other applications. This work describes the image-based quantification of color and its machine vision and offline applications in interdisciplinary fields using specifically developed image analysis software. Examples of color information extraction from a single pixel to predetermined sizes/shapes of areas, including customized regions of interest (ROIs) from various digital images of dyed T-shirts, tongues, and assays, are demonstrated. Corresponding RGB, HSV, CIELAB, Munsell color, and hexadecimal color codes, from a single pixel to ROIs, are extracted for machine vision and offline applications in various fields. Histograms and statistical analyses of colors from a single pixel to ROIs are successfully demonstrated. Reliable image-based quantification of color, in a wide range of potential applications, is proposed and the validity is verified using color quantification examples in various fields of applications. The objectivity of color-based diagnosis, judgment and control can be significantly improved by the image-based quantification of color proposed in this study. Full article
(This article belongs to the Special Issue Image and Signal Processing)
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18 pages, 7297 KiB  
Article
PHB/PEG Nanofiber Mat Obtained by Electrospinning and Their Performances
by Nguyen Hong Thanh, Roman Olekhnovich, Vera Sitnikova, Arina Kremleva, Petr Snetkov and Mayya Uspenskaya
Technologies 2023, 11(2), 48; https://doi.org/10.3390/technologies11020048 - 24 Mar 2023
Cited by 8 | Viewed by 2353
Abstract
In this work, a nanofiber mat based on PHB/PEG with various PEG contents was obtained by electrospinning process. The thermal and mechanical properties of the PHB/PEG nanofiber mat were investigated. In addition, PHB/PEG nanofiber mats were characterized by Fourier transforms infrared spectroscopy (FTIR), [...] Read more.
In this work, a nanofiber mat based on PHB/PEG with various PEG contents was obtained by electrospinning process. The thermal and mechanical properties of the PHB/PEG nanofiber mat were investigated. In addition, PHB/PEG nanofiber mats were characterized by Fourier transforms infrared spectroscopy (FTIR), differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and water contact angle measurement. It was shown that, by increasing the PEG contents from 1 to 4%, the average diameter of PHB nanofibers decreased from 1177 nm to 1101 nm, corresponding to 2% PEG, then the diameter of the fiber increased again from 1101 nm to 1136 nm, corresponding to 4% PEG. Tensile strength increased from 3.6 MPa to 4.4 MPa, then decreased from 4.4 MPa to 2.9 MPa. Thermogravimetric analysis showed a difference in the process of thermal degradation of nanofiber mats. The degree of crystallinity measured by XRD and DSC methods gives different values at some points. The results demonstrated that adding PEG improved the mechanical properties, hydrophobicity, porosity, and thermal stability of the PHB fiber mat, which showed that the PHB/PEG nanofiber mat has great potential for air filtration or water filtration. Full article
(This article belongs to the Special Issue Electrospinning Technologies for Biomedical and Biotechnological Applications—Volume II)
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19 pages, 10511 KiB  
Article
Mobilenetv2_CA Lightweight Object Detection Network in Autonomous Driving
by Peicheng Shi, Long Li, Heng Qi and Aixi Yang
Technologies 2023, 11(2), 47; https://doi.org/10.3390/technologies11020047 - 23 Mar 2023
Cited by 1 | Viewed by 1451
Abstract
A lightweight network target detection algorithm was proposed, based on MobileNetv2_CA, focusing on the problem of high complexity, a large number of parameters, and the missed detection of small targets in the target detection network based on candidate regions and regression methods in [...] Read more.
A lightweight network target detection algorithm was proposed, based on MobileNetv2_CA, focusing on the problem of high complexity, a large number of parameters, and the missed detection of small targets in the target detection network based on candidate regions and regression methods in autonomous driving scenarios. First, Mosaic image enhancement technology is used in the data pre-processing stage to enhance the feature extraction of small target scenes and complex scenes; second, the Coordinate Attention (CA) mechanism is embedded into the Mobilenetv2 backbone feature extraction network, combined with the PANet and Yolo detection heads for multi-scale feature fusion; finally, a Lightweight Object Detection Network is built. The experimental test results show that the designed network obtained the highest average detection accuracy of 81.43% on the Voc2007 + 2012 dataset, and obtained the highest average detection accuracy of 85.07% and a detection speed of 31.84 FPS on the KITTI dataset. The total amount of network parameters is only 39.5 M. This is beneficial to the engineering application of MobileNetv2 network in automatic driving. Full article
(This article belongs to the Special Issue Image and Signal Processing)
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22 pages, 19077 KiB  
Article
GDAL and PROJ Libraries Integrated with GRASS GIS for Terrain Modelling of the Georeferenced Raster Image
by Polina Lemenkova and Olivier Debeir
Technologies 2023, 11(2), 46; https://doi.org/10.3390/technologies11020046 - 22 Mar 2023
Cited by 6 | Viewed by 2114
Abstract
Libraries with pre-written codes optimize the workflow in cartography and reduce labour intensive data processing by iteratively applying scripts to implementing mapping tasks. Most existing Geographic Information System (GIS) approaches are based on traditional software with a graphical user’s interface which significantly limits [...] Read more.
Libraries with pre-written codes optimize the workflow in cartography and reduce labour intensive data processing by iteratively applying scripts to implementing mapping tasks. Most existing Geographic Information System (GIS) approaches are based on traditional software with a graphical user’s interface which significantly limits their performance. Although plugins are proposed to improve the functionality of many GIS programs, they are usually ad hoc in finding specific mapping solutions, e.g., cartographic projections and data conversion. We address this limitation by applying the principled approach of Geospatial Data Abstraction Library (GDAL), library for conversions between cartographic projections (PROJ) and Geographic Resources Analysis Support System (GRASS) GIS for geospatial data processing and morphometric analysis. This research presents topographic analysis of the dataset using scripting methods which include several tools: (1) GDAL, a translator library for raster and vector geospatial data formats used for converting Earth Global Relief Model (ETOPO1) GeoTIFF in XY Cartesian coordinates into World Geodetic System 1984 (WGS84) by the ‘gdalwarp’ utility; (2) PROJ projection transformation library used for converting ETOPO1 WGS84 grid to cartographic projections (Cassini–Soldner equirectangular, Equal Area Cylindrical, Two-Point Equidistant Azimuthal, and Oblique Mercator); and (3) GRASS GIS by sequential use of the following modules: r.info, d.mon, d.rast, r.colors, d.rast.leg, d.legend, d.northarrow, d.grid, d.text, g.region, and r.contour. The depth frequency was analysed by the module ‘d.histogram’. The proposed approach provided a systematic way for morphometric measuring of topographic data and combine the advantages of the GDAL, PROJ, and GRASS GIS tools that include the informativeness, effectiveness, and representativeness in spatial data processing. The morphometric analysis included the computed slope, aspect, profile, and tangential curvature of the study area. The data analysis revealed the distribution pattern in topographic data: 24% of data with elevations below 400 m, 13% of data with depths −5000 to −6000 m, 4% of depths have values −3000 to −4000 m, the least frequent data (−6000 to 7000 m) <1%, 2% of depths have values −2000 to 3000 m in the basin, while other values are distributed proportionally. Further, by incorporating the generic coordinate transformation software library PROJ, the raster grid was transformed into various cartographic projections to demonstrate distortions in shape and area. Scripting techniques of GRASS GIS are demonstrated for applications in topographic modelling and raster data processing. The GRASS GIS shows the effectiveness for mapping and visualization, compatibility with libraries (GDAL, PROJ), technical flexibility in combining Graphical User Interface (GUI), and command-line data processing. The research contributes to the technical cartographic development. Full article
(This article belongs to the Special Issue Image and Signal Processing)
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16 pages, 5576 KiB  
Article
A Gas Leakage Detection Device Based on the Technology of TinyML †
by Vasileios Tsoukas, Anargyros Gkogkidis, Eleni Boumpa, Stefanos Papafotikas and Athanasios Kakarountas
Technologies 2023, 11(2), 45; https://doi.org/10.3390/technologies11020045 - 22 Mar 2023
Cited by 4 | Viewed by 3413
Abstract
Internet of Things devices are frequently used as consumer devices to provide digital solutions, such as smart lighting and digital voice-activated assistants, but they are also employed to alert residents in the instance of an emergency. Given the increasingly costly nature of present [...] Read more.
Internet of Things devices are frequently used as consumer devices to provide digital solutions, such as smart lighting and digital voice-activated assistants, but they are also employed to alert residents in the instance of an emergency. Given the increasingly costly nature of present neural network systems, it is necessary to transport information to the cloud for intelligent machine analysis. TinyML is a potential technology that has been presented by the research world for building fully independent and safe devices that can gather, analyze, and produce data, without transferring it to distant organizations. This paper describes a gas leakage detection system based on TinyML. The proposed solution can be programmed to identify anomalies and warn occupants via the utilization of the BLE technology, in addition to an incorporated LCD screen. Experiments have been employed to show and assess two distinct test situations. For the first occasion, the smoke detection test case, the system earned an F1-Score of 0.77, whereas the F1-Score for the ammonia test case was 0.70. Full article
(This article belongs to the Special Issue MOCAST 2022)
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17 pages, 2022 KiB  
Review
How to Bell the Cat? A Theoretical Review of Generative Artificial Intelligence towards Digital Disruption in All Walks of Life
by Subhra Mondal, Subhankar Das and Vasiliki G. Vrana
Technologies 2023, 11(2), 44; https://doi.org/10.3390/technologies11020044 - 17 Mar 2023
Cited by 30 | Viewed by 11587
Abstract
Generative Artificial Intelligence (GAI) has brought revolutionary changes to the world, enabling businesses to create new experiences by combining virtual and physical worlds. As the use of GAI grows along with the Metaverse, it is explored by academics, researchers, and industry communities for [...] Read more.
Generative Artificial Intelligence (GAI) has brought revolutionary changes to the world, enabling businesses to create new experiences by combining virtual and physical worlds. As the use of GAI grows along with the Metaverse, it is explored by academics, researchers, and industry communities for its endless possibilities. From ChatGPT by OpenAI to Bard AI by Google, GAI is a leading technology in physical and virtual business platforms. This paper focuses on GAI’s economic and societal impact and the challenges it poses. Businesses must rethink their operations and strategies to create hybrid physical and virtual experiences using GAI. This study proposes a framework that can help business managers develop effective strategies to enhance their operations. It analyzes the initial applications of GAI in multiple sectors to promote the development of future customer solutions and explores how GAI can help businesses create new value propositions and experiences for their customers, and the possibilities of digital communication and information technology. A research agenda is proposed for developing GAI for business management to enhance organizational efficiency. The results highlight a healthy conversation on the potential of GAI in various business sectors to improve customer experience. Full article
(This article belongs to the Section Information and Communication Technologies)
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13 pages, 326 KiB  
Opinion
Matching Assistive Technology, Telerehabilitation, and Virtual Reality to Promote Cognitive Rehabilitation and Communication Skills in Neurological Populations: A Perspective Proposal
by Fabrizio Stasolla, Antonella Lopez, Khalida Akbar, Leonarda Anna Vinci and Maria Cusano
Technologies 2023, 11(2), 43; https://doi.org/10.3390/technologies11020043 - 16 Mar 2023
Cited by 4 | Viewed by 2325
Abstract
Neurological populations (NP) commonly experience several impairments. Beside motor and sensorial delays, communication and intellectual disabilities are included. The COVID-19 pandemic has suddenly exacerbated their clinical conditions due to lockdown, quarantine, and social distancing preventive measures. Healthcare services unavailability has negatively impacted NP [...] Read more.
Neurological populations (NP) commonly experience several impairments. Beside motor and sensorial delays, communication and intellectual disabilities are included. The COVID-19 pandemic has suddenly exacerbated their clinical conditions due to lockdown, quarantine, and social distancing preventive measures. Healthcare services unavailability has negatively impacted NP clinical conditions, partially mitigated by vaccine diffusion. One way to overcome this issue is the use of technology-aided interventions for both assessment and rehabilitative purposes. Assistive technology-based interventions, telerehabilitation, and virtual reality setups have been widely adopted to help individuals with neurological damages or injuries. Nevertheless, to the best of our knowledge, their matching (i.e., combination or integration) has rarely been investigated. The main objectives of the current position paper were (a) to provide the reader with a perspective proposal on the matching of the three aforementioned technological solutions, (b) to outline a concise background on the use of technology-aided solutions, (c) to argue on the effectiveness and the suitability of technology-mediated programs, and (d) to postulate an integrative proposal to support cognitive rehabilitation including assistive technology, telerehabilitation, and virtual reality. Practical implications for both research and practice are critically discussed. Full article
(This article belongs to the Section Assistive Technologies)
10 pages, 753 KiB  
Perspective
Developments and Applications of Artificial Intelligence in Music Education
by Xiaofei Yu, Ning Ma, Lei Zheng, Licheng Wang and Kai Wang
Technologies 2023, 11(2), 42; https://doi.org/10.3390/technologies11020042 - 16 Mar 2023
Cited by 38 | Viewed by 10534
Abstract
With the continuous developments of information technology, advanced computer technology and information technology have been promoted and used in the field of music. As one of the products of the rapid development of information technology, Artificial Intelligence (AI) involves many interdisciplinary subjects, adding [...] Read more.
With the continuous developments of information technology, advanced computer technology and information technology have been promoted and used in the field of music. As one of the products of the rapid development of information technology, Artificial Intelligence (AI) involves many interdisciplinary subjects, adding new elements to music education. By analyzing the advantages of AI in music education, this paper systematically summarizes the application of AI in music education and discusses the development prospects of AI in music education. With the aid of AI, the combination of intelligent technology and on-site teaching solves the lack of individuation in the traditional mode and enhances students’ interest in learning. Full article
(This article belongs to the Special Issue 10th Anniversary of Technologies—Recent Advances and Perspectives)
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10 pages, 1723 KiB  
Article
Comparative Effect of the Type of a Pulsed Discharge on the Ionic Speciation of Plasma-Activated Water
by Victor Panarin, Eduard Sosnin, Andrey Ryabov, Victor Skakun, Sergey Kudryashov and Dmitry Sorokin
Technologies 2023, 11(2), 41; https://doi.org/10.3390/technologies11020041 - 14 Mar 2023
Cited by 1 | Viewed by 1337
Abstract
The comparison of ion concentrations, pH index, and conductivity in distilled and ground water after exposure to low-temperature plasma formed by barrier and bubble discharges is performed. It has been found that in the case of groundwater, the best performance for the production [...] Read more.
The comparison of ion concentrations, pH index, and conductivity in distilled and ground water after exposure to low-temperature plasma formed by barrier and bubble discharges is performed. It has been found that in the case of groundwater, the best performance for the production of NO3− anions is provided by the discharge inside the gas bubbles. For distilled water, the barrier discharge in air, followed by saturation of water with plasma products, is the most suitable from this point of view. In both treatments, the maximum energy input into the stock solution is ensured. After 10 min treatment of ground water, the pH index increases and then it decreases. The obtained numerical indicators make it possible to understand in which tasks the indicated treatment modes should be used, their comparative advantages, and disadvantages. From the point of view of energy consumption for obtaining approximately equal (in order of magnitude) amounts of NO3− anions, both types of discharge treatment are suitable. The research results point to a fairly simple way to convert salts (calcium carbonates) from an insoluble form to soluble one. Namely, when interacting with NO3− anions, insoluble carbonates pass into soluble nitrates. Full article
(This article belongs to the Special Issue Advanced Processing Technologies of Innovative Materials)
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14 pages, 277 KiB  
Review
A Review of Deep Transfer Learning and Recent Advancements
by Mohammadreza Iman, Hamid Reza Arabnia and Khaled Rasheed
Technologies 2023, 11(2), 40; https://doi.org/10.3390/technologies11020040 - 14 Mar 2023
Cited by 76 | Viewed by 13657
Abstract
Deep learning has been the answer to many machine learning problems during the past two decades. However, it comes with two significant constraints: dependency on extensive labeled data and training costs. Transfer learning in deep learning, known as Deep Transfer Learning (DTL), attempts [...] Read more.
Deep learning has been the answer to many machine learning problems during the past two decades. However, it comes with two significant constraints: dependency on extensive labeled data and training costs. Transfer learning in deep learning, known as Deep Transfer Learning (DTL), attempts to reduce such reliance and costs by reusing obtained knowledge from a source data/task in training on a target data/task. Most applied DTL techniques are network/model-based approaches. These methods reduce the dependency of deep learning models on extensive training data and drastically decrease training costs. Moreover, the training cost reduction makes DTL viable on edge devices with limited resources. Like any new advancement, DTL methods have their own limitations, and a successful transfer depends on specific adjustments and strategies for different scenarios. This paper reviews the concept, definition, and taxonomy of deep transfer learning and well-known methods. It investigates the DTL approaches by reviewing applied DTL techniques in the past five years and a couple of experimental analyses of DTLs to discover the best practice for using DTL in different scenarios. Moreover, the limitations of DTLs (catastrophic forgetting dilemma and overly biased pre-trained models) are discussed, along with possible solutions and research trends. Full article
(This article belongs to the Special Issue Data Science and Big Data in Biology, Physical Science and Engineering)
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23 pages, 5488 KiB  
Article
Non-Contact In-Vehicle Occupant Monitoring System Based on Point Clouds from FMCW Radar
by Yixuan Chen, Yunlong Luo, Jianhua Ma, Alex Qi, Runhe Huang, Francesco De Paulis and Yihong Qi
Technologies 2023, 11(2), 39; https://doi.org/10.3390/technologies11020039 - 13 Mar 2023
Cited by 2 | Viewed by 2497
Abstract
In order to reduce the probability of automobile safety incidents, the in-vehicle occupant monitoring is indispensable. However, occupant monitoring using frequency-modulated continuous wave (FMCW) radar can be challenging due to the interference from passengers’ posture, movement, and the presence of multiple people. This [...] Read more.
In order to reduce the probability of automobile safety incidents, the in-vehicle occupant monitoring is indispensable. However, occupant monitoring using frequency-modulated continuous wave (FMCW) radar can be challenging due to the interference from passengers’ posture, movement, and the presence of multiple people. This paper proposes an improved method for generating point clouds using FMCW radar. The approach involves point cloud clustering, post-processing operations such as segmentation, merging, and filtering of the clustered point cloud to match the actual in-vehicle environment, and a state machine combination step. Experimental results show that the proposed method can achieve high recognition accuracy in scenarios with multiple passengers who are moving and sitting in a relaxed manner. Full article
(This article belongs to the Section Information and Communication Technologies)
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15 pages, 3882 KiB  
Review
Aging Mechanism and Models of Supercapacitors: A Review
by Ning Ma, Dongfang Yang, Saleem Riaz, Licheng Wang and Kai Wang
Technologies 2023, 11(2), 38; https://doi.org/10.3390/technologies11020038 - 03 Mar 2023
Cited by 33 | Viewed by 3881
Abstract
Electrochemical supercapacitors are a promising type of energy storage device with broad application prospects. Developing an accurate model to reflect their actual working characteristics is of great research significance for rational utilization, performance optimization, and system simulation of supercapacitors. This paper presents the [...] Read more.
Electrochemical supercapacitors are a promising type of energy storage device with broad application prospects. Developing an accurate model to reflect their actual working characteristics is of great research significance for rational utilization, performance optimization, and system simulation of supercapacitors. This paper presents the fundamental working principle and applications of supercapacitors, analyzes their aging mechanism, summarizes existing supercapacitor models, and evaluates the characteristics and application scope of each model. By examining the current state and limitations of supercapacitor modeling research, this paper identifies future development trends and research focuses in this area. Full article
(This article belongs to the Special Issue 10th Anniversary of Technologies—Recent Advances and Perspectives)
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23 pages, 2478 KiB  
Systematic Review
The Use of Domain-Specific Languages for Visual Analytics: A Systematic Literature Review
by Alireza Khakpour, Ricardo Colomo-Palacios, Antonio Martini and Mary Sánchez-Gordón
Technologies 2023, 11(2), 37; https://doi.org/10.3390/technologies11020037 - 02 Mar 2023
Cited by 1 | Viewed by 1778
Abstract
Visual Analytics (VA) is a multidisciplinary field that requires various skills including but not limited to data analytics, visualizations, and the corresponding domain knowledge. Recently, many studies proposed creating and using Domain-Specific Languages (DSLs) for VA in order to abstract complexities and assist [...] Read more.
Visual Analytics (VA) is a multidisciplinary field that requires various skills including but not limited to data analytics, visualizations, and the corresponding domain knowledge. Recently, many studies proposed creating and using Domain-Specific Languages (DSLs) for VA in order to abstract complexities and assist designers in developing better VAs for different data domains. However, development methods and types of DSLs vary for different applications and objectives. In this study, we conducted a systematic literature review to overview DSL methods and their intended applications for VA systems. Moreover, the review outlines the benefits and limitations of each of these methods. The aim is to provide decision support for both the research and development communities to choose the most compatible approach for their application. We think the communication of this research delivers a broad figure of previous relevant research and assists with the transfer and adaptation of the results to other domains. Full article
(This article belongs to the Section Information and Communication Technologies)
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29 pages, 2313 KiB  
Article
Reconstruction of Industrial and Historical Heritage for Cultural Enrichment Using Virtual and Augmented Reality
by Lukas Paulauskas, Andrius Paulauskas, Tomas Blažauskas, Robertas Damaševičius and Rytis Maskeliūnas
Technologies 2023, 11(2), 36; https://doi.org/10.3390/technologies11020036 - 25 Feb 2023
Cited by 12 | Viewed by 3211
Abstract
Because of its benefits in providing an engaging and mobile environment, virtual reality (VR) has recently been rapidly adopted and integrated in education and professional training. Augmented reality (AR) is the integration of VR with the real world, where the real world provides [...] Read more.
Because of its benefits in providing an engaging and mobile environment, virtual reality (VR) has recently been rapidly adopted and integrated in education and professional training. Augmented reality (AR) is the integration of VR with the real world, where the real world provides context and the virtual world provides or reconstructs missing information. Mixed reality (MR) is the blending of virtual and physical reality environments allowing users to interact with both digital and physical objects at the same time. In recent years, technology for creating reality-based 3D models has advanced and spread across a diverse range of applications and research fields. The purpose of this paper is to design, develop, and test VR for kinaesthetic distance learning in a museum setting. A VR training program has been developed in which learners can select and perform pre-made scenarios in a virtual environment. The interaction in the program is based on kinaesthetic learning characteristics. Scenarios with VR controls simulate physical interaction with objects in a virtual environment for learners. Learners can grasp and lift objects to complete scenario tasks. There are also simulated devices in the virtual environment that learners can use to perform various actions. The study’s goal was to compare the effectiveness of the developed VR educational program to that of other types of educational material. Our innovation is the development of a system for combining their 3D visuals with rendering capable of providing a mobile VR experience for effective heritage enhancement. Full article
(This article belongs to the Special Issue Immersive Technologies and Applications on Arts, Culture and Tourism)
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28 pages, 1321 KiB  
Article
A Layer-Wise Coupled Thermo-Elastic Shell Model for Three-Dimensional Stress Analysis of Functionally Graded Material Structures
by Salvatore Brischetto, Domenico Cesare and Roberto Torre
Technologies 2023, 11(2), 35; https://doi.org/10.3390/technologies11020035 - 24 Feb 2023
Cited by 4 | Viewed by 1458
Abstract
In this work, a coupled 3D thermo-elastic shell model is presented. The primary variables are the scalar sovra-temperature and the displacement vector. This model allows for the thermal stress analysis of one-layered and sandwich plates and shells embedding Functionally Graded Material (FGM) layers. [...] Read more.
In this work, a coupled 3D thermo-elastic shell model is presented. The primary variables are the scalar sovra-temperature and the displacement vector. This model allows for the thermal stress analysis of one-layered and sandwich plates and shells embedding Functionally Graded Material (FGM) layers. The 3D equilibrium equations and the 3D Fourier heat conduction equation for spherical shells are put together into a set of four coupled equations. They automatically degenerate in those for simpler geometries thanks to proper considerations about the radii of curvature and the use of orthogonal mixed curvilinear coordinates α, β, and z. The obtained partial differential governing the equations along the thickness direction are solved using the exponential matrix method. The closed form solution is possible assuming simply supported boundary conditions and proper harmonic forms for all the unknowns. The sovra-temperature amplitudes are directly imposed at the outer surfaces for each geometry in steady-state conditions. The effects of the thermal environment are related to the sovra-temperature profiles through the thickness. The static responses are evaluated in terms of displacements and stresses. After a proper and global preliminary validation, new cases are presented for different thickness ratios, geometries, and temperature values at the external surfaces. The considered FGM is metallic at the bottom and ceramic at the top. This FGM layer can be embedded in a sandwich configuration or in a one-layered configuration. This new fully coupled thermo-elastic model provides results that are coincident with the results proposed by the uncoupled thermo-elastic model that separately solves the 3D Fourier heat conduction equation. The differences are always less than 0.5% for each investigated displacement, temperature, and stress component. The differences between the present 3D full coupled model and the the advantages of this new model are clearly shown. Both the thickness layer and material layer effects are directly included in all the conducted coupled thermal stress analyses. Full article
(This article belongs to the Special Issue 10th Anniversary of Technologies—Recent Advances and Perspectives)
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15 pages, 14241 KiB  
Article
Dual-Band Rectifier Circuit Design for IoT Communication in 5G Systems
by Ioannis D. Bougas, Maria S. Papadopoulou, Achilles D. Boursianis, Spyridon Nikolaidis and Sotirios K. Goudos
Technologies 2023, 11(2), 34; https://doi.org/10.3390/technologies11020034 - 24 Feb 2023
Cited by 2 | Viewed by 2121
Abstract
Radio-frequency (RF) energy harvesting (EH) is emerging as a reliable and constantly available free energy source. The primary factor determining whether this energy can be utilized is how efficiently it can be collected. In this work, an RF EH system is presented. More [...] Read more.
Radio-frequency (RF) energy harvesting (EH) is emerging as a reliable and constantly available free energy source. The primary factor determining whether this energy can be utilized is how efficiently it can be collected. In this work, an RF EH system is presented. More particularly, we designed a dual-band RF to DC rectifier circuit at sub-6 GHz in the 5G bands, able to supply low-power sensors and microcontrollers used in agriculture, the military, or health services. The system operates at 3.5 GHz and 5 GHz in the 5G cellular network’s frequency band FR1. Numerical results reveal that the system provides maximum power conversion efficiency (PCE) equal to 53% when the output load (sensor or microcontroller) is 1.74 kΩ and the input power is 12 dBm. Full article
(This article belongs to the Special Issue Intelligent Reflecting Surfaces for 5G and Beyond)
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14 pages, 955 KiB  
Article
On the Sliding Mode Control Applied to a DC-DC Buck Converter
by Sandra Huerta-Moro, Oscar Martínez-Fuentes, Victor Rodolfo Gonzalez-Diaz and Esteban Tlelo-Cuautle
Technologies 2023, 11(2), 33; https://doi.org/10.3390/technologies11020033 - 23 Feb 2023
Viewed by 2243
Abstract
This work shows the voltage regulation of a DC–DC buck converter by applying sliding mode control using three different cases of sliding surfaces. The DC–DC buck converter is modeled by ordinary differential equations (ODEs) that are solved by applying numerical methods. The ODEs [...] Read more.
This work shows the voltage regulation of a DC–DC buck converter by applying sliding mode control using three different cases of sliding surfaces. The DC–DC buck converter is modeled by ordinary differential equations (ODEs) that are solved by applying numerical methods. The ODEs describe two state variables that are associated to the capacitor voltage and the inductor current. The state variable associated to voltage is regulated by applying two well-known sliding surfaces and a third one that is introduced herein to improve the response of the sliding mode control. The stability of the proposed sliding surface is verified by using a Lyapunov theorem to guarantee closed-loop stability. Finally, simulation results show the improvement of voltage regulation when applying the proposed sliding surface compared to already reported approaches. Full article
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