Technologies

26 pages, 1662 KiB

Open AccessArticle

Applications of Brain Wave Classification for Controlling an Intelligent Wheelchair

by Maria Carolina Avelar, Patricia Almeida, Brigida Monica Faria and Luis Paulo Reis

Technologies 2024, 12(6), 80; https://doi.org/10.3390/technologies12060080 (registering DOI) - 3 Jun 2024

The independence and autonomy of both elderly and disabled people have been a growing concern in today’s society. Therefore, wheelchairs have proven to be fundamental for the movement of these people with physical disabilities in the lower limbs, paralysis, or other type of [...] Read more.

The independence and autonomy of both elderly and disabled people have been a growing concern in today’s society. Therefore, wheelchairs have proven to be fundamental for the movement of these people with physical disabilities in the lower limbs, paralysis, or other type of restrictive diseases. Various adapted sensors can be employed in order to facilitate the wheelchair’s driving experience. This work develops the proof concept of a brain–computer interface (BCI), whose ultimate final goal will be to control an intelligent wheelchair. An event-related (de)synchronization neuro-mechanism will be used, since it corresponds to a synchronization, or desynchronization, in the mu and beta brain rhythms, during the execution, preparation, or imagination of motor actions. Two datasets were used for algorithm development: one from the IV competition of BCIs (A), acquired through twenty-two Ag/AgCl electrodes and encompassing motor imagery of the right and left hands, and feet; and the other (B) was obtained in the laboratory using an Emotiv EPOC headset, also with the same motor imaginary. Regarding feature extraction, several approaches were tested: namely, two versions of the signal’s power spectral density, followed by a filter bank version; the use of respective frequency coefficients; and, finally, two versions of the known method filter bank common spatial pattern (FBCSP). Concerning the results from the second version of FBCSP, dataset A presented an F1-score of 0.797 and a rather low false positive rate of 0.150. Moreover, the correspondent average kappa score reached the value of 0.693, which is in the same order of magnitude as 0.57, obtained by the competition. Regarding dataset B, the average value of the F1-score was 0.651, followed by a kappa score of 0.447, and a false positive rate of 0.471. However, it should be noted that some subjects from this dataset presented F1-scores of 0.747 and 0.911, suggesting that the movement imagery (MI) aptness of different users may influence their performance. In conclusion, it is possible to obtain promising results, using an architecture for a real-time application. Full article

(This article belongs to the Special Issue The Future of Healthcare: Biomedical Technology and Integrated Artificial Intelligence)

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13 pages, 13200 KiB

Open AccessArticle

Comparison of a Custom-Made Inexpensive Air Permeability Tester with a Standardized Measurement Instrument

by Dietrich Spädt, Niclas Richter, Cornelia Golle, Andrea Ehrmann and Lilia Sabantina

Technologies 2024, 12(6), 79; https://doi.org/10.3390/technologies12060079 (registering DOI) - 2 Jun 2024

Abstract

The air permeability of a textile fabric belongs to the parameters which characterize its potential applications as garments, filters, airbags, etc. Calculating the air permeability is complicated due to its dependence on many other fabric parameters, such as porosity, thickness, weaving parameters and [...] Read more.

The air permeability of a textile fabric belongs to the parameters which characterize its potential applications as garments, filters, airbags, etc. Calculating the air permeability is complicated due to its dependence on many other fabric parameters, such as porosity, thickness, weaving parameters and others, which is why the air permeability is usually measured. Standardized measurement instruments according to EN ISO 9237, however, are expensive and complex, prohibiting small companies or many universities from using them. This is why a simpler and inexpensive test instrument was suggested in a previous paper. Here, we show correlations between the results of the standardized and the custom-made instrument and verify this correlation using fluid dynamics calculations. Full article

(This article belongs to the Section Innovations in Materials Processing)

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28 pages, 1067 KiB

Open AccessArticle

Smart Energy Systems Based on Next-Generation Power Electronic Devices

by Nikolay Hinov

Technologies 2024, 12(6), 78; https://doi.org/10.3390/technologies12060078 (registering DOI) - 1 Jun 2024

Abstract

Power electronics plays a key role in the management and conversion of electrical energy in a variety of applications, including the use of renewable energy sources such as solar, wind and hydrogen energy, as well as in electric vehicles, industrial technologies, homes and [...] Read more.

Power electronics plays a key role in the management and conversion of electrical energy in a variety of applications, including the use of renewable energy sources such as solar, wind and hydrogen energy, as well as in electric vehicles, industrial technologies, homes and smart grids. These technologies are essential for the successful implementation of the green transition, as they help reduce carbon emissions and promote the production and consumption of cleaner and more sustainable energy. The present work presents a new generation of power electronic devices and systems, which includes the following main aspects: advances in semiconductor technologies, such as the use of silicon carbide (SiC) and gallium nitride (GaN); nanomaterials for the realization of magnetic components; using a modular principle to construct power electronic devices; applying artificial intelligence techniques to device lifecycle design; and the environmental aspects of design. The new materials allow the devices to operate at higher voltages, temperatures and frequencies, making them ideal for high-power applications and high-frequency operation. In addition, the development of integrated and modular power electronic systems that combine energy management, diagnostics and communication capabilities contributes to the more intelligent and efficient management of energy resources. This includes integration with the Internet of Things (IoT) and artificial intelligence (AI) for automated task solving and work optimization. Full article

(This article belongs to the Special Issue Smart Systems (SmaSys2023))

23 pages, 5805 KiB

Open AccessArticle

Deep Learning Approaches for Water Stress Forecasting in Arboriculture Using Time Series of Remote Sensing Images: Comparative Study between ConvLSTM and CNN-LSTM Models

by Ismail Bounoua, Youssef Saidi, Reda Yaagoubi and Mourad Bouziani

Technologies 2024, 12(6), 77; https://doi.org/10.3390/technologies12060077 (registering DOI) - 1 Jun 2024

Abstract

Irrigation is crucial for crop cultivation and productivity. However, traditional methods often waste water and energy due to neglecting soil and crop variations, leading to inefficient water distribution and potential crop water stress. The crop water stress index (CWSI) has become a widely [...] Read more.

Irrigation is crucial for crop cultivation and productivity. However, traditional methods often waste water and energy due to neglecting soil and crop variations, leading to inefficient water distribution and potential crop water stress. The crop water stress index (CWSI) has become a widely accepted index for assessing plant water status. However, it is necessary to forecast the plant water stress to estimate the quantity of water to irrigate. Deep learning (DL) models for water stress forecasting have gained prominence in irrigation management to address these needs. In this paper, we present a comparative study between two deep learning models, ConvLSTM and CNN-LSTM, for water stress forecasting using remote sensing data. While these DL architectures have been previously proposed and studied in various applications, our novelty lies in studying their effectiveness in the field of water stress forecasting using time series of remote sensing images. The proposed methodology involves meticulous preparation of time series data, where we calculate the crop water stress index (CWSI) using Landsat 8 satellite imagery through Google Earth Engine. Subsequently, we implemented and fine-tuned the hyperparameters of the ConvLSTM and CNN-LSTM models. The same processes of model compilation, optimization of hyperparameters, and model training were applied for the two architectures. A citrus farm in Morocco was chosen as a case study. The analysis of the results reveals that the CNN-LSTM model excels over the ConvLSTM model for long sequences (nine images) with an RMSE of 0.119 and 0.123, respectively, while ConvLSTM provides better results for short sequences (three images) than CNN-LSTM with an RMSE of 0.153 and 0.187, respectively. Full article

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18 pages, 26070 KiB

Open AccessArticle

Vertical Balance of an Autonomous Two-Wheeled Single-Track Electric Vehicle

by David Rodríguez-Rosa, Andrea Martín-Parra, Andrés García-Vanegas, Francisco Moya-Fernández, Ismael Payo-Gutiérrez and Fernando J. Castillo-García

Technologies 2024, 12(6), 76; https://doi.org/10.3390/technologies12060076 - 28 May 2024

Viewed by 335

Abstract

In the dynamic landscape of autonomous transport, the integration of intelligent transport systems and embedded control technology is pivotal. While strides have been made in the development of autonomous agents and multi-agent systems, the unique challenges posed by two-wheeled vehicles remain largely unaddressed. [...] Read more.

In the dynamic landscape of autonomous transport, the integration of intelligent transport systems and embedded control technology is pivotal. While strides have been made in the development of autonomous agents and multi-agent systems, the unique challenges posed by two-wheeled vehicles remain largely unaddressed. Dedicated control strategies for these vehicles have yet to be developed. The vertical balance of an autonomous two-wheeled single-track vehicle is a challenge for engineering. This type of vehicle is unstable and its dynamic behaviour changes with the forward velocity. We designed a scheduled-gain proportional–integral controller that adapts its gains to the forward velocity, maintaining the vertical balance of the vehicle by means of the steering front-wheel angle. The control law was tested with a prototype designed by the authors under different scenarios, smooth and uneven floors, maintaining the vertical balance in all cases. Full article

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19 pages, 3842 KiB

Open AccessArticle

Intelligent Cane for Assisting the Visually Impaired

by Claudiu-Eugen Panazan and Eva-Henrietta Dulf

Technologies 2024, 12(6), 75; https://doi.org/10.3390/technologies12060075 - 27 May 2024

Viewed by 420

Abstract

Those with visual impairments, including complete blindness or partial sight loss, constitute a significant global population. According to estimates by the World Health Organization (WHO), there are at least 2.2 billion people worldwide who have near or distance vision disorders. Addressing their needs [...] Read more.

Those with visual impairments, including complete blindness or partial sight loss, constitute a significant global population. According to estimates by the World Health Organization (WHO), there are at least 2.2 billion people worldwide who have near or distance vision disorders. Addressing their needs is crucial. Introducing a smart cane tailored for the blind can greatly improve their daily lives. This paper introduces a significant technical innovation, presenting a smart cane equipped with dual ultrasonic sensors for obstacle detection, catering to the visually impaired. The primary focus is on developing a versatile device capable of operating in diverse conditions, ensuring efficient obstacle alerts. The strategic placement of ultrasonic sensors facilitates the emission and measurement of high-frequency sound waves, calculating obstacle distances and assessing potential threats to the user. Addressing various obstacle types, two ultrasonic sensors handle overhead and ground-level barriers, ensuring precise warnings. With a detection range spanning 2 to 400 cm, the device provides timely information for user reaction. Dual alert methods, including vibrations and audio signals, offer flexibility to users, controlled through intuitive switches. Additionally, a Bluetooth-connected mobile app enhances functionality, activating audio alerts if the cane is misplaced or too distant. Cost-effective implementation enhances accessibility, supporting a broader user base. This innovative smart cane not only represents a technical achievement but also significantly improves the quality of life for visually impaired individuals, emphasizing the social impact of technology. The research underscores the importance of technological research in addressing societal challenges and highlights the need for solutions that positively impact vulnerable communities, shaping future directions in research and technological development. Full article

(This article belongs to the Section Assistive Technologies)

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12 pages, 4704 KiB

Open AccessArticle

Effect of Oscillating Area on Generating Microbubbles from Hollow Ultrasonic Horn

by Kodai Hasegawa, Nobuhiro Yabuki and Toshinori Makuta

Technologies 2024, 12(6), 74; https://doi.org/10.3390/technologies12060074 - 25 May 2024

Viewed by 222

Abstract

Microbubbles, which are tiny bubbles with a diameter of less than 100 µm, have been attracting attention in recent years. Conventional methods of microbubble generation using porous material and swirling flows have problems such as large equipment size and non-uniform bubble generation. Therefore, [...] Read more.

Microbubbles, which are tiny bubbles with a diameter of less than 100 µm, have been attracting attention in recent years. Conventional methods of microbubble generation using porous material and swirling flows have problems such as large equipment size and non-uniform bubble generation. Therefore, we have been developing a hollow ultrasonic horn with an internal flow path as a microbubble-generating device. By supplying gas and ultrasonic waves simultaneously, the gas–liquid interface is violently disturbed to generate microbubbles. Although this device can generate microbubbles even in highly viscous fluids and high-temperature fluids such as molten metals, it has the problem of generating many relatively large bubbles of 1 mm or more. Since the generation of a large amount of microbubbles in a short period of time is required to realize actual applications in agriculture, aquaculture, and medicine, conventional research has tried to solve this problem by increasing the amplitude of the ultrasonic oscillation. However, it is difficult to further increase the amplitude due to the structural reasons of the horn and the behavior of bubbles at the horn tip; therefore, the oscillating area of the tip of the horn, which had not received attention before, was enlarged by a factor of 2.94 times to facilitate the ultrasonic wave transmission to the bubbles, and the effect of this was investigated. As a result, a large number of gases were miniaturized, especially at high gas flow rates, leading to an increase in the amount of microbubbles generated. Full article

(This article belongs to the Special Issue Smart Systems (SmaSys2023))

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21 pages, 8976 KiB

Open AccessArticle

Gamified VR Storytelling for Cultural Tourism Using 3D Reconstructions, Virtual Humans, and 360° Videos

by Emmanouil Kontogiorgakis, Emmanouil Zidianakis, Eirini Kontaki, Nikolaos Partarakis, Constantina Manoli, Stavroula Ntoa and Constantine Stephanidis

Technologies 2024, 12(6), 73; https://doi.org/10.3390/technologies12060073 - 22 May 2024

Viewed by 350

Abstract

This work addresses the lack of methodologies for the seamless integration of 360° videos, 3D digitized artifacts, and virtual human agents within a virtual reality environment. The proposed methodology is showcased in the context of a tour guide application and centers around the [...] Read more.

This work addresses the lack of methodologies for the seamless integration of 360° videos, 3D digitized artifacts, and virtual human agents within a virtual reality environment. The proposed methodology is showcased in the context of a tour guide application and centers around the innovative use of a central hub, metaphorically linking users to various historical locations. Leveraging a treasure hunt metaphor and a storytelling approach, this combination of digital structures is capable of building an exploratory learning experience. Virtual human agents contribute to the scenario by offering personalized narratives and educational content, contributing to an enriched cultural heritage journey. Key contributions of this research include the exploration of the symbolic use of the central hub, the application of a gamified approach through the treasure hunt metaphor, and the seamless integration of various technologies to enhance user engagement. This work contributes to the understanding of context-specific cultural heritage applications and their potential impact on cultural tourism. The output of this research work is the reusable methodology and its demonstration in the implemented showcase application that was assessed by a heuristic evaluation. Full article

(This article belongs to the Section Information and Communication Technologies)

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Technologies, Volume 12, Issue 6 (June 2024) – 8 articles

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