Politecnio die Bari - Catalogo di prodotti della Ricerca
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Le fortificazioni di Rutigliano: studio e ricostruzione tramite il rilievo digitale
No full textThe territory of Rutigliano (Bari), from a geomorphological point of view, is characterized by the presence of two “lame” (erosional valleys with seasonal torrent like flow): Giotta and San Giorgio, between which, in the early medieval period, a small settlement called Loco Rutigliano was estabilished. Although the existence of the settlement is traced back to the 10th century, the first certain reference is from 1059, the year in which, with a papal bull, a small, fortified village is mentioned. The village developed around a donjon (Torre Maestra), erected on a motte. This type of settlement, of North European origin, was introduced by the Normans, who are credited with the first fortifications of the village. The Torre Maestra became the central element from which urban development with a concentric layout radiated. From this central element, a trapezoidal enclosure was created, defining the perimeter of a small castle, which featured two additional towers at its remaining two corners, one likely identical to the Torre Maestra and a third tower, smaller and currently less visible. Surrounding this enclosure, a wall circuit was established, characterized by cylindrical towers and three city gates. Additionally, a postern with a drawbridge is documented as an entrance to the castle. Although studies on the reconstruction of the fortification system have already been initiated over the years, these studies are not sufficiently detailed. They are outdated and primarily based on archival research. This study aims to deepen these investigations using aerial and terrestrial photogrammetric survey methodologies, laser scanning, and 3D modeling, in order to provide new and more accurate elements for scientific reconstruction based on survey data alongside documentary evidence
Proof-of-Concept Study on the Use of Virtual Reality with Evocative and Aesthetic Content for Elderly Individuals with Cognitive Decline
No full textRecent technological advances have introduced novel therapeutic interventions for Alzheimer’s disease (AD). This study introduces a novel virtual reality (VR) intervention consisting of aesthetically pleasing and relaxing immersive videos paired with evocative music for patients with or without cognitive decline. The goal of this intervention is to improve the mood, evoke autobiographical memories in, and enhance the overall well-being of elderly individuals, across stages of cognitive decline (from absent to severe). Twenty-one elderly participants (5 cognitively healthy, 13 with a mild cognitive decline, 2 with a moderate decline, and 1 with a severe decline) were exposed to immersive 360-degree videos depicting both familiar and unfamiliar, pleasant and calming environments, accompanied by emotionally evocative, pleasant, and soothing music. The results demonstrated high levels of immersion and predominantly positive emotional responses, with several participants reporting autobiographical memory recall triggered by the VR stimulation. Statistical analysis revealed a significant improvement in mood over time, regardless of cognitive status, supporting the effectiveness of the intervention. While there were some side effects of fatigue or transient anxiety, the experience was generally perceived as engaging and meaningful. This feasibility study adds to the acceptability and potential clinical utility of VR interventions and provides a justification for future larger trials aimed at the integration of immersive technologies into cognitive rehabilitation interventions for individuals at different stages of cognitive decline
Looking at the Stars: Status shifts after collective achievements
No full textWe analyze how collective awards shape status shifts within teams. Integrating the relational and the public recognition perspectives on status formation, we argue that status shifts arise from both internal team composition and external recognition. The presence of a high-status member amplifies audience arousal, leading to a disproportionate attribution of the award's value. This heightened arousal also strengthens audience memory, resulting in more persistent status gains for all team members. Our analysis is grounded in the film industry and based on a sample of 6,632 actor-film pairs related to the period 2000–2013. Results show that all team members experience a positive status shift after receiving a collective award. However, high-status members experience a higher positive status shift compared to the others. Results highlight that the positive status shifts due to the collective award winning tend to last after some time, in the presence of high-status members in the team
Development of innovative procedures and algorithms for non-destructive quantitative evaluation of damage in materials for aeronautics by means of active thermography techniques
Get PDFThe aim of this thesis is to develop innovative procedures for quantitatively evaluating defects or, more in general, damage in materials. These procedures will be outlined to reduce both the experimental tests and the computational time with the final goal of promoting active thermographic techniques and more in general, Non-destructive Testing (NDT) in industrial applications. Therefore, the collaboration with Diagnostic Engineering Solutions (DES) S.r.l, a spin-off of the Polytechnic of Bari, has been fundamental for customizing suitable procedures to satisfy the needs of the company.
In this regard, all the thermography techniques, such as lock-in, pulsed, and step have been considered for inspecting and characterizing the defects/damage within a wide range of materials by adopting both traditional methods and artificial intelligence algorithms (machine and deep learning). More in detail, a one-dimensional convolutive neural network (CNN) has been adopted and thermal temporal data has been provided as an input to train the net. The adoption of a deep learning algorithm has been useful in achieving a double goal: characterizing the defect and speeding up the test phase for inspecting the component.
The powerful but also the limits of using the artificial intelligence approach with respect to traditional techniques will be critically discussed
Development of fast-actuation piezo systems for high-performance Fluid Power technologies
Get PDFThis PhD research project investigates the transformative potential of piezoelectric actuators in addressing the inherent limitations and problems of conventional hydraulic components, particularly focusing on valves and pumps.
Despite the great advantages it offers, such as high-power density, precise control and large force output, conventional hydraulic technology suffers from low energy efficiency due to substantial energy losses that occur as the pressurized oil flows through the hydraulic circuit and its components, particularly the control-ones. Conventional hydraulic technology typically utilizes analogue spool valves, such as proportional and servovalves, as control components in various industrial and aeronautical applications where high precision and fast response are required. However, the spool design of these valves leads to high power dissipation, caused by the significant pressure drop across the small narrow passages uncovered during valve control. Moreover, the actuation system's architecture introduces additional drawbacks, such as increased complexity and higher manufacturing costs, which remain still unresolved.
To explore these challenges, the research begins by developing comprehensive simulation models of aircraft fuel systems, specifically focusing on quantifying energy inefficiencies in servovalves within fuel metering units. Building on these insights, the first goal of the project is to design and model innovative spool valve architectures powered by piezoelectric actuators, replacing traditional electromagnetic actuators. By leveraging the fast response times and simplicity of piezoelectric materials, this approach aims to improve energy efficiency, reduce costs, and simplify the design of conventional spool valves.
The project also explores the potential of digital hydraulics, which aims to replace conventional proportional and servovalves in industrial and aeronautical applications with low-cost, robust on/off valves in order to minimize power dissipation. However, the practical implementation of digital hydraulics is currently limited by challenges in manufacturing on/off valves that meet strict requirements, such as high switching frequencies and speeds (below 5 ms), minimal pressure losses, and the ability to handle large flow rates in a compact form. Once again, piezoelectric actuators could provide a crucial solution to these challenges. Thus, the second goal of this research is to design and model innovative high-frequency switching on/off valve architectures, marking digital hydraulics as a promising technology for improving energy efficiency in various fluid power applications.
Lastly, this research addresses, as third goal, the growing demand for pumps in industries such as chemistry, biomedicine, aerospace, robotics, and liquid cooling. These fields require pumps that are compact, reliable, quiet, and capable of precise flow control—qualities that conventional hydraulic pumps often struggle to meet due to inherent structural limitations. Specifically, the research project explores the use over again of piezoelectric actuators to design, develop and testing innovative precision fluid pumps that can meet these stringent requirements, aiming to expand the power capabilities of this innovative technology
A Robust Design approach for error reduction in Thermoelastic Stress Analysis on Ti6Al4V alloy in presence of unknow biaxial residual stresses
Get PDFIn this study, a general model for Thermoelastic Stress Analysis (TSA) was employed in conjunction with simulated random noise sources to evaluate errors in the experimental technique using a robust design approach as a preliminary analysis. This facilitated the identification of an optimal experimental setup and anticipated ranges of measurement errors for TSA reducing testing time and errors. The model's validity was confirmed through TSA experiments conducted on AA2024 samples exhibiting biaxial residual stresses, as measured by a standard testing method. ANOVA (Analysis of Variance) and ANOM (Analysis of Means) analyses were conducted to explore the impact of parameters describing the analytical relationship between thermoelastic response and stresses in the presence of noise factors. The Robust Design approach was applied to the TSA measurement methodology, involving simulations of various noise sources and potential errors in the process, along with the application of different calibration methods
Modeling, Positioning, and Deep Reinforcement Learning Path Following Control of Scaled Robotic Vehicles: Design and Experimental Validation
Get PDFMobile robotic systems serve as versatile platforms for diverse indoor applications, ranging from warehousing and manufacturing to test benches dedicated to evaluating automated driving (AD) functions. In AD systems, the path following (PF) layer is responsible for defining steering commands to follow the reference path. Recently explored approaches involve artificial intelligence-based methods, such as Deep Reinforcement Learning (DRL). Despite their promising performance, these controllers still suffer from time-consuming training phases and may experience performance degradation when deviating from training conditions. To address these challenges, this paper proposes novel DRL controllers addressing the simulation-to-reality gap in unknown scenarios by: (i) training via an expert demonstrator which also speed up the learning phase; and (ii) a weight adaptation strategy for the resulting neural network (NN) to strengthen controller robustness and enhance PF performance. In addition, an experimentally validated vehicle model is used for training the proposed DRL algorithm and as a model for a federated extended Kalman filter (FEKF) system employed for sensor fusion in vehicle localisation. The proposed DRL-based PF controllers are experimentally evaluated through key performance indicators across multiple maneuvers not considered during training, and it is shown that they outperform benchmarking model-based controllers from the literature. Note to Practitioners - This paper presents a comprehensive toolchain for controlling mobile robots, which includes: (i) a simple yet effective two-stage least-square approach for parameter identification of the longitudinal and lateral dynamics of scaled robotic vehicles; (ii) the utilisation of a no-reset FEKF to enhance positioning leveraging all sensors commonly available on scaled robotic vehicles; (iii) the inclusion of an expert demonstrator to expedite the training phase and address the simulation-to-reality gap resulting from discrepancies between simulation and experimental environments; and (iv) an adaptation strategy for dynamically adjusting the weights of the resulting NN to further improve robustness for scenarios not considered during the traning
A Procedure to Model and Simulate Customized Porous Scaffolds Employed in Tissue Regeneration
No full textRegenerative medicine is an emerging discipline that investigates the possibilities of restoring portions of damaged biological tissues in a controlled way. An interesting practice in this field consists in the implantation of biomimetic scaffolds colonized by mesenchymal stem cells taken from the patient. In this work, a set of design guidelines for customized biomimetic scaffolds was analyzed, and a full procedure aimed at implementing them for the treatment of a real clinical case was outlined. In detail, a highly sustainable and biocompatible material obtained from chemical processing of fish industry by-products was selected. The primary phases of the proposed design procedure consisted in biomedical data acquisition, parametric modelling of the damaged region to regenerate, structural design of the scaffold based on the avoidance of stress shielding effects, and evaluation of the physiological pressure to apply on the implanted porous construct to maximize mature bone formation. The presented procedure resulted as an effective practice for the design of personalized biomimetic scaffolds for tissue regeneration, thus providing at the same time many insights towards novel sustainable design solutions in biomedical fields
Geometrical acoustic modelling of occupied acoustic conditions in mosques: Application to a case study
Get PDFOld religious buildings represent an essential cultural heritage whatever the country or the religion they belong to. Thanks to many researches carried out in the last years, their acoustics is now considered part of this heritage. However, for practical reasons, their acoustic characterization is often made under unoccupied conditions, while, given the frequent use of hard reflecting surfaces, the occupied conditions may differ significantly. Geometrical acoustics may represent, if properly used, a valid tool to simulate how sound propagates in an occupied space, allowing to investigate the effect on the full set of acoustic parameters. Occupancy in mosques may be more challenging to simulate than in other spaces because of the different postures of the worshippers and the usually high absorption that they introduce because of high density of occupants. To correctly simulate such effects, a specific modelling approach has been proposed starting from reverberant chamber measurements and validating them against on-site measurements. Using the proposed method, the effect of occupancy in the Jedid Mosque in Algiers, which was built in 1660, in a typical Ottoman style, and later restored in 1855, was studied. The mosque was chosen because it is large and reverberant to allow a better appreciation of the variations due to occupancy. The geometrical acoustic model was first carefully calibrated against measurements in unoccupied conditions, which also pointed out a clearly non-diffuse behaviour in the space, and, finally the occupancy was added. Results showed that due to the strong concentration of absorbing elements on the floor, where carpets already contributed to absorb sound, the occupancy mostly affected reverberation parameters, while clarity for speech remained poor
