Search Results (709)

Drivers’ facial expression recognition systems play a pivotal role in Advanced Driver Assistance Systems (ADASs) by monitoring emotional states and detecting fatigue or distractions in real time. However, deploying such systems in resource-constrained environments like vehicles requires lightweight architectures to ensure real-time performance, efficient model updates, and compatibility with embedded hardware. Smaller models significantly reduce communication overhead in distributed training. For autonomous vehicles, lightweight architectures also minimize the data transfer required for over-the-air updates. Moreover, they are crucial for their deployability on hardware with limited on-chip memory. In this work, we propose a novel Dual Attention Lightweight Deep Learning (DALDL) approach for drivers’ facial expression recognition. The proposed approach combines the SqueezeNext architecture with a Dual Attention Convolution (DAC) block. Our DAC block integrates Hybrid Channel Attention (HCA) and Coordinate Space Attention (CSA) to enhance feature extraction efficiency while maintaining minimal parameter overhead. To evaluate the effectiveness of our architecture, we compare it against two baselines: (a) Vanilla SqueezeNet and (b) AlexNet. Compared with SqueezeNet, DALDL improves accuracy by 7.96% and F1-score by 7.95% on the KMU-FED dataset. On the CK+ dataset, it achieves 8.51% higher accuracy and 8.40% higher F1-score. Against AlexNet, DALDL improves accuracy by 4.34% and F1-score by 4.17% on KMU-FED. Lastly, on CK+, it provides a 5.36% boost in accuracy and a 7.24% increase in F1-score. These results demonstrate that DALDL is a promising solution for efficient and accurate emotion recognition in real-world automotive applications. Full article

Carbon-neutral and carbon-negative construction is gaining significant interest in the home building industry. Accordingly, the development of new materials and innovative redesign of the existing materials are on the rise. This paper presents the results of a review study on hempcrete as a new, emerging construction material, which is crop-based and is accordingly expected to provide a highly sustainable construction system. The paper reviews the mixture design, properties and attributes, different methods for its application in construction, building code requirements for construction of hempcrete homes, mechanical and structural properties for home building, and evaluation of the current state of hempcrete application as a non-load-bearing construction material. The paper also reviews the status of developments toward using hempcrete as a load-bearing system. The study shows a snapshot of the methods used for the construction of hempcrete buildings and touches on efforts that are ongoing to increase the compressive strength of hempcrete toward load-bearing applications. Such an increase would depend on different factors such as curing temperature and humidity, binder type and percentage, hemp-to-binder ratio, water-to-binder ratio, and additives. Full article

In a scenario where fuel costs are notably high and the policies that we are currently witnessing tend to limit the fossil fuel resource that powers most heavy goods transport services, the optimization of space in vehicles transporting these goods, such as trucks and shipping containers, becomes an indisputable and urgent need. This urgency is manifested in the need to minimize the costs associated with transport, given its increasing growth. This experiment aims to study and implement an Internet of Things (IoT)-based solution to the problem previously presented. The developed system comprises a computer and a millimeter-wave (mmWave) sensor. The computer processes the data captured by the sensor through code in Python language and displays, through a web page allocated in a cloud/server, the volume occupied by the load, as well as the percentage of occupied and free space, considering the volume provided by the user. The validation tests consisted of checking the results in 2D and 3D, all carried out in a controlled environment focused on the detection of static objects. For the 3D analysis, the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm was used to obtain the points for extracting the volume of the detected object. Several objects with different dimensions were used and the error ranged from 0.6% to 7.61%. These results denote the confirmation of the reliability and efficacy of the presented solution. With this, it was concluded that this new solution has significant potential to enter the market and compete with other existing technologies. Full article

In the field of rehabilitation exoskeletons, addressing the needs of users and healthcare professionals is essential for the development of effective medical technologies. This study presents a user-centered evaluation of the ARTH-aid ExoGlove, a proposed rehabilitation device for muscle atrophy caused by rheumatoid arthritis. This study assesses usability and user experience through therapist and patient feedback, focusing on ergonomic and functional aspects. Ensuring compliance with usability and adaptability criteria is crucial before implementation to enhance effectiveness in clinical settings. While this study includes user feedback, further technical validation and refinement of the system are needed. The findings provide insights into patients’ perceptions of usability and impact on mobility, as well as therapists’ perspectives on its potential integration into rehabilitation protocols. These results highlight the importance of iterative validation and reinforce the role of rehabilitation technologies in complementing traditional therapeutic approaches and advancing patient-centered innovation in biomedical design. Full article

Dynamic building envelopes integrated with renewable energy sources, termed Dynamic and Renewable Source Building Envelopes (DREBE), provide an innovative approach to optimizing building envelope designs. Yet, these systems are not mature enough and not widely adopted in the industry and few literature resources are employed to understand them. These systems dynamically respond and adapt to various environmental, energy, and occupancy demands for higher energy efficiency and comfort levels compared to traditional building envelopes while simultaneously producing energy. Their potential in climate change mitigation and fostering sustainable urban development warrants great attention from industry and urban planners. Especially in positive energy districts, which aim to reach net-positive energy goals through utilizing smart energy efficient building systems on the district level. This paper reviews innovative systems like dynamic photovoltaic shading devices and phase change materials and evaluates their performance by answering two research questions, what are the current DBE trends and are they feasible in achieving net-positive energy consumption? The analysis conducted reveals the dominance of solar-based dynamic renewable energy systems and a great need for alternatives. The study suggests that alternatives like wind as a renewable energy source should be studied with dynamic systems. Moreover, the study highlights current research gaps including insufficient data on long-term application and economic costs associated with such systems. To address this gap, the study suggests exploring in depth some of these systems and then branching into various combinations of dynamic envelope systems with multiple renewable or adaptive components to further enhance the overall building performance. By synthesizing the current body of literature, this paper gives insights into advancing the application of the dynamic building envelope systems and highlights their crucial role in the future of sustainable urban environments. Full article

Centrifugal pumps are known to efficiently transport water from a certain point. However, they developed great concerns in water supply and distribution applications regarding their operating efficiency, which were caused by the accumulated losses and sudden power consumption growth. Thus, mitigating these concerns is important to improve the performance of the centrifugal pump. This study used ANSYS 2022 R2 for the optimization design process, combining the strengths of Computational Fluid Dynamics (CFD) and Response Surface Method (RSM), to come up with an optimal design for a centrifugal water pump. Splitter blades, with a length of 80% of the main blade, were included in the design to assess their effects on the performance of the pump. Design parameters such as the placement of the splitter blades, their ellipse ratios, and the volute tongue, were also investigated for further improvement. Results indicate that finding a perfect balance between the placement of the splitter blades, the design of the volute tongue clearance and thickness, and configuring the ellipse ratio of the splitter blades improves the pump’s performance. The optimal design results in 27.35%, 15.70%, 28.18%, 16.67%, and 8.36% improvement in total efficiency, total head, static efficiency, static head, and power consumption, respectively. Full article

This study is part of the research project Dep-Project: Design and Embodiment of Wearable Prostheses, funded by the Foundation for Science and Technology (FCT), whose main objective is the development of wearable myoelectric prostheses for upper limbs, which are economically accessible, socially accepted, and personalizable. In this context, the need arose to create an online platform with an intuitive interface, which would facilitate the access to persons with upper limb amputation to information about prosthetics and allow them to personalize their prosthesis, according to their aesthetic preferences. Thus, this work aims to demonstrate the importance of designing interfaces for greater inclusion, as well as demonstrating and describing the efficiency of the design process adopted with the aim of potentially being adopted in similar cases. The methodology adopted was Design Thinking, an approach centered on user needs. The development of the platform involved the creation of user personas, information architecture, user flows, wireframes, wireflows, and a design system. The interactive prototype underwent usability testing to evaluate the user experience and identify possible areas for improvement. The results, obtained through the System Usability Scale (SUS) post-test questionnaire, revealed a high success rate, which confirmed the efficiency of the designed solution. Full article

This article explores the feasibility of miniaturizing and packaging fiber Bragg grating (FBG)-based distributed optical fiber smart sensors (DOFSS) for future flight trials. It highlights the importance of real-time, high-speed sensing in aerospace, particularly for hypersonic vehicles, and the challenges of conventional system integration. The advantages of FBG technology for structural health monitoring, temperature, and pressure sensing are examined. Potential systems, including light sources, spectral detection, and processing units, are discussed, along with challenges such as temperature fluctuations and vibrations. Innovations in photonic devices, fabrication, and packaging are emphasized, focusing on developing compact and robust FBG interrogation systems. The article proposes designs for integrated photonic circuits in FBG interrogation systems. The trade-offs between miniaturization and performance, considering sensitivity, resolution, and durability are also assessed. Finally, future research directions are outlined to enhance the sensitivity, resolution, and robustness of FBG interrogators while enabling miniaturization and multifunctionality. The article concludes by summarizing the potential for miniaturizing and packaging FBG-based DOFSS for aerospace flight trials. Full article

Drug-coated balloons (DCBs) are designed to deliver an anti-proliferative drug to the stenotic vessel to combat restenosis after an angioplasty treatment. However, significant drug loss can occur during device navigation toward the lesion site, thus reducing the delivery efficiency and increasing the off-target drug loss. In this framework, this study aimed to design a novel in vitro setup to estimate the drug loss due to blood flow–coating interaction during tracking. The system consists of a millifluidic chamber, able to host small drug-coated flat patches representative of DCBs, connected at the inlet to a syringe pump able to provide an ad hoc flow and, at the outlet, to a vial collecting the testing fluid with possible drug removed from the specimen. Unlike other studies, the device presented here uniquely evaluates flow-related drug loss from smaller-scale DCB samples, making it a precise, easy-to-use, and efficient assessment tool. In order to define proper boundary conditions for these washing off tests, computational fluid dynamics (CFD) models of a DCB in an idealized vessel were developed to estimate the wall shear stresses (WSSs) experienced in vivo by the device when inserted into leg arteries. From these simulations, different target WSSs were identified as of interest to be replicated in the in vitro setup. A combined analytical–CFD approach was followed to design the testing system and set the flow rates to be imposed to generate the desired WSSs. Finally, a proof-of-concept study was performed by testing eight coated flat specimens and analyzing drug content via high-performance liquid chromatography (HPLC). Results indicated different amounts of drug loss according to the different imposed WSSs and confirmed the suitability of the designed system to assess the washing off resistance of different drug coatings for angioplasty balloons. Full article

Decisions made during the design phase of mechatronic systems have a considerable influence on their entire life cycle. The persistent calls for environmental protection are driven by global megatrends promoting sustainability. Hence, opting for eco-designed mechatronic systems is now a fundamental cornerstone of manufacturers’ strategies. This paper is a generalization of the environmental assessment step of a sustainable design methodology applied to mechatronic systems with structural design freeze, which is only relevant for a limited set of admissible mechatronic solutions. The approach is adapted to cover any dimension of admissible solutions using hierarchical timed colored Petri nets (hierarchical TCPN) and simplified life cycle assessments (SLCAs). First, the SLCAs results are integrated into the hierarchical TCPN model. Next, a weighting process is introduced to ensure the classification of the heterogeneous impact categories derived from SLCAs according to agreed impact reduction criteria. Then, the candidate ecological solution and its design environmental matrix (DEM) are determined via simulations. The methodology is implemented using a regenerative braking system (RBS) with frozen structural specifications, focusing on its production phase and using CPN tools and OpenLCA software. It enables the selection of the candidate ecological RBS among a large set of admissible solutions. This selection is established without interrupting the normal design process but simply by adding an extra step. Full article

Motion assistance is a growing need that is linked to the aging of the population, and solutions are required with adequate structures and functionality. Specific attention is paid to finger exoskeletons both for motion exercises and for rehabilitation therapies. The paper presents a new finger exoskeleton structure that is designed with a parallel cable-driven structure with adequate functionality for autonomous use by users. The main advantages can be appreciated in the operational efficiency in assisting finger motion and lightness of the design that also permits easy wearing with the proposed solution installed on a fabric glove. The exoskeleton is designed with a functional characterization through performance analysis thanks to a laboratory prototype that is built for experimental validation tests. The presented prototype appears to be easy to wear and operate with wide possibilities of implementation for motion exercises in rehabilitation and for elderly people. Full article

Seismic isolation is a vital strategy for improving the earthquake resilience of structures, utilizing flexible components such as lead–rubber bearings (LRBs) and curved surface sliders (CSSs) to attenuate ground motion effects. This paper presents a comprehensive comparative analysis of seismic isolation design methodologies prescribed in the U.S. code (ASCE 7-22) and the European code (EC8). The focus is on the equivalent lateral force method, also known as the simplified linear method, renowned for its simplicity and efficiency in seismic design applications. A six-story steel building serves as a case study to examine the discrepancies between the two codes. The structure was modeled and subjected to nonlinear time-history analysis (NTHA) using 20 ground motion records, selected and scaled to match a conditional mean spectrum (CMS). Key performance indicators—including displacement at the isolation level, base shear forces, story shear forces, and story drifts—were compared to assess the reliability and effectiveness of each code’s design approach. The findings reveal notable differences between ASCE 7-22 and EC8, particularly in seismic hazard characterization and the calculation of design displacements. ASCE 7-22 generally adopts a more conservative stance, especially for CSSs, resulting in overestimations of design displacements and lateral seismic forces. In contrast, EC8’s simplified method aligns more closely with observed performance for LRBs. However, when applied to CSSs, simplified methods prove less reliable, underscoring the need for more precise analytical techniques. Full article

The zygomatic bone area experiences frequent mechanical damage in the middle craniofacial region, including the orbital floor. The orbital floor bone is very thin, ranging from 0.74 mm to 1.5 mm. Enhancing digitization, reconstruction, and CAD modeling procedures is essential to improving the visualization of this structure. Achieving a homogeneous surface with high manufacturing accuracy is crucial for developing precise surgical models and tools for creating titanium mesh implants to reconstruct the orbital floor geometry. This article improved the accuracy of reconstruction and CAD modeling using the example of the development of a prototype implant to replace the zygomatic bone and a tool to form the geometry of the titanium mesh within the geometry of the orbital floor. The masked stereolithography (mSLA) method was used in the model manufacturing process because it is low-cost and highly accurate. Two manufacturing modes (standard and ultra-light) were tested on an Anycubic Photon M3 Premium 3D printer to determine which mode produced a more accurate representation of the geometry. To verify the geometric accuracy of the manufactured models, a GOM Scan1 structured light scanner was used. In the process of evaluating the accuracy of the model preparation, the maximum deviation, mean deviation, range and standard deviation were determined. The maximum deviations for anatomical structures created using the normal mode ranged from ±0.6 mm to ±0.7 mm. In contrast, models produced with the ultra-light mode showed deviations of ±0.5 mm to ±0.6 mm. Furthermore, the results indicate that the ultra-light mode offers better surface accuracy for die and stamp models. More than 70% of the surface of the models is within the deviation range of ±0.3 mm, which is sufficient for planning surgical procedures. However, the guidelines developed in the presented publication need to optimize the CAD process and select 3D-printing parameters to minimize deviations, especially at the edges of manufactured models. Full article

The exploitation of immersive simulation platforms to improve traditional training techniques in the agricultural industry sector would enable year-round accessibility, flexibility, safety, and consistent high-quality training for agricultural operators. An innovative workflow in virtual simulations for training and educational purposes includes an immersive environment in which the operator can interact with plants through haptic interfaces, following instructions imparted by a non-playing character (NPC) instructor. This study allows simulating the pruning of a complex case study, a hazelnut tree, reproduced in very high detail to offer agricultural operators a more realistic and immersive training environment than those currently existing. The process of creating a multisensorial environment starts with the integrated survey of the plant with a laser scanner and photogrammetry and then generates a controllable parametric model from roots to leaves with the exact positioning of the original branches. The model is finally inserted into a simulation, where haptic gloves with tactile resistance responsive to model collisions are tested. The results of the experimentation demonstrate the correct execution of this innovative design simulation, in which branches and leaves can be cut using a shear, with immediate sensory feedback. The project therefore aims to finalize this product as a realistic training platform for pruning, but not limited to it, paving the way for high-fidelity simulation for many other types of operations and specializations. Full article

Material selection is essential for advancing sustainability in construction. Biocomposites contribute significantly to raising the awareness of materials derived from biomass. This paper explores the design development and application of novel natural fibre pultruded biocomposite profiles in a deployable system. Development methods include geometrical studies to create a system that transforms from flat to three-dimensional. Physical and digital models were used to refine the geometry, while connection elements were designed to suit material properties and deployability requirements. The first case study, at a furniture scale, demonstrates the use of the profiles connected using threading methods to create a lightweight multifunctional deployable system enabling easy transport and storage. This system can be locked at various heights for different purposes. The realised structure weighs 4 kg, supporting weights up to 150 kg. The second case study applies the system architecturally in an adaptive kinetic facade, adjusting to the sun’s position for optimal shading, providing up to 70% daylight when open and as little as 20% when closed. These two structures validate the developed deployable system, showcasing the versatility of biocomposite profiles in such configurations. This approach enhances sustainability in architecture by enabling lightweight, adaptable, and eco-friendly building solutions. Full article