Politecnio die Bari - Catalogo di prodotti della Ricerca
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SYNTHETIC APERTURE RADAR PAYLOADS: MIGRATION TOWARDS PHOTONIC APPROACH
No full textThe application of Photonic Integrated Circuits (PICs) to Telecommunications payloads has already demonstrated several benefits, such as an increase in SNR performance, a significant reduction in power consumption, a GHz-precision RF signal processing capability, fast and large bandwidth for data transfer. Hence, during the last years, it has also tried to spread the photonic approach to the Synthetic Aperture Radar (SAR) subsystems, mainly providing wider bandwidth and larger tunability with respect to microelectronic technologies. This migration could interest several basic SAR building blocks, such as the transmission section, the beamforming networks, the data processing, and the analog-to-digital converters. Here, the design of an innovative photonic SAR payload, with sub-meter spatial resolution (< 90 cm) in stripmap mode and operating in Ka-band (35.75 GHz), is proposed. The breakthroughs pertain to a high-performance linearly chirped waveform generator (with a time-bandwidth product > 103 and a phase noise at 10 kHz from the carrier < -110 dBc/Hz), a Fast-Fourier-Transform (FFT) data processor (operating in real-time (≈ ns), 8-bit resolution, and 300 MHz sampling spacing of the upconverted signal), and an innovative beamforming network configuration (featuring squint-free wide bandwidth of 500 MHz, steering angle of ± 15°, and overall power consumption of ≈ 1 kW)
Preliminary Characterization of a Non-contact Breath Monitoring System for Infants
No full textRespiratory disorders are the highest cause of mortality among infants. Technologies for health monitoring can help to avoid those underhanded events. In this paper, we propose a system for respiratory health monitoring. The system is non-invasive and the monitoring is performed in a contactless manner since it is based on Time-of-Flight sensors and post-processing. To validate the proposed system we proposed an experimental setup aiming to precisely emulate the breathing activity. The emulator is built around a step motor and a microcontroller, and it allows to seamlessly emulate breathing patterns. Preliminary results from the experimental campaign in a real-world scenario prove the effectiveness of the approach
Sound insulation improvements in lift-and-slide window systems
No full textIn recent years, significant attention has been directed towards enhancing indoor comfort in buildings, with acoustic comfort emerging as a key area of study. The sound insulation properties of building façades have a considerable influence on acoustic comfort, with glazing system often representing the most critical components. Meanwhile, the ever increasing demand for larger window surfaces to improve visual comfort, has led to a growing prevalence of thermal break lift-and-slide systems. The choice of window frame design for this window system is of paramount importance to achieve high sound insulation performance, as this depends on the closure system, the frame cross section, and the glass configuration in the frame. This paper aims to highlight critical issues of large sliding windows, exploring the acoustic performance of a lift-and-slide window through experimental assessments according to the ISO 10140 standard. The weighted sound reduction index (Rw) was assessed in laboratory; then, several modifications were implemented to improve the acoustic performance of lift-and-slide windows. Notably, the incorporation of sound-absorbing materials within the upper section of the frame yielded an Rw enhancement of 2 dB on average. Conversely, deficiencies such as improper glass orientation or improper frame closure systems led to Rw reductions of up to 4 dB. Finally, this study underlines the critical issues identified during the tests and provides practical recommendations to mitigate common installation errors
LISE: a Logic-based Interactive Similarity Explainer for clusters of RDF data
Get PDFClustering methods are instrumental in the preliminary analysis of unstructured data, yet interpreting the resulting groups – especially in the context of RDF (Resource Description Framework) data — poses significant challenges. This paper introduces LISE (Logic-based Interactive Similarity Ex- plainer), an integrated and model-agnostic framework designed to generate explainable, human-readable insights into clusters of RDF resources. LISE combines four core components: (i) a machine learning module leveraging vector embeddings and k-means clustering; (ii) a logic-based reasoning component that computes the common semantic features of clustered items via an optimized Least Common Subsumer (LCS); (iii) a Natural Language Generation (NLG) module that verbalizes these features into structured and human- readable explanations; and (iv) an interactive user feedback loop that captures user perception of explanation relevance to iteratively enhance embedding quality and cluster interpretability. An extensive use case on the DrugBank dataset demonstrates LISE ’s ability to generate meaningful, context-aware cluster explanations and adapt to user preferences, advancing the state of explainable AI for semantic web technologies and knowledge graph analytics. The paper investigates also the integration in LISE of an LLM-based NLG approach, both in the DrugBank use case and through an extended experiment in a general-purpose dataset: YAGO3-10
Low computational cost algorithm for harmonic elimination in multilevel converters
No full textThis paper presents an improved selective harmonic elimination procedure for L-level cascaded H-bridge converters operating at the fundamental switching frequency. The procedure is subject to the constraint that l=2⋅2n+1, where n is an integer. Previously, the unknown switching angles were obtained using an analytical formula and the arccos function. The new method replaces the arccos function with a Maclaurin series truncated at the third term. This modification offers the following advantages: (i) much less computational effort; (ii) the absence of truncation errors; (iii) the ability to eliminate low order n harmonics and their multiples from the output voltage waveform, while keeping the fundamental fixed; (iv) low total harmonic distortion with a wide range of modulation indices. In some cases, the procedure mitigates other low order harmonics, in addition to selected harmonics elimination, to meet standard code requirements. The algorithm was successfully simulated for a three-phase inverter assuming l=5,9, and 17 levels
Measurement of neutron production in atmospheric neutrino interactions at Super-Kamiokande
No full textModelling the complexity of interconnected energy systems at different urban scales: a critical review
No full textThe urgent need to reverse global climate change necessitates rethinking the design and operation of human-made systems. Urban energy systems, a major source of greenhouse gas emissions, are a key focus to enhance sustainability. Addressing challenges such as renewable energy integration, energy storage, reducing building energy consumption, innovative mobility systems, and improving energy infrastructure flexibility drives the development of reliable, multi-scale models capable of capturing complex dynamics. This review evaluates the current state of urban energy modelling from a novel perspective, focusing on interactions across different scales: end-users, buildings, and districts/cities. It critically assesses existing models' strengths and limitations in addressing the complexity of urban energy systems, identifying gaps in the literature and highlighting emerging trends. The review underscores a paradigm shift towards more end-user-centric modelling approaches, which aim to better capture human behaviour and its impact on energy use. Additionally, it stresses the growing demand for integrated, interdisciplinary simulation tools to address challenges such as demand flexibility. The findings advocate for next-generation urban energy models to move beyond building-focused perspectives, adopting approaches that emphasise end-users and their interactions with clean, affordable energy hubs. The review outlines future directions to improve model accuracy and scalability, supporting the transition to sustainable and resilient urban energy systems
Cammini e territori. Un approccio walkshop per la rigenerazione culturale e socio-economica
No full textRecentemente, le Long-distance Walking Routes (LDWR) sono state promosse per stimolare lo sviluppo economico
locale e migliorare l'attrattività delle aree interne. Tuttavia, la promozione istituzionale di queste vie, tramite un
approccio top-down, rischia di generare conflitti locali e generare overtourism, impoverimento della vitalità economica e
spopolamento. L’articolo discute il metodo del walkshop per lo sviluppo di percorsi al di fuori degli itineraritradizionali,
espandendo il concetto di turismo lento e sostenibile per creare opportunità economiche locali e valorizzare comunità
fragili. Il potenziale di questo approccio viene analizzato grazie a un caso di studio transfrontaliero tra Europa centrale
e orientale, la Via Egnatia. Attraverso il caso studio l’articolo indaga i fattori chiave per il successo e la sostenibilità
delle LDWR non convenzionali, come l'interazione tra camminatori e comunità locali, la sensibilizzazione
socioculturale e la valorizzazione dei patrimoni storici e culturali. Si analizza inoltre l’efficacia del walkshop nel generare
proposte operative per una pianificazione sostenibile e partecipativa dei percorsi, dalle strategie locali agli output a
livello nazionale. Questo lavoro contribuisce al dibattito accademico su come promuovere un turismo lento e
sostenibile attraverso i cammini, attivando socialmente ed economicamente le aree al di fuori degli itinerari tradizionali
Integration of EV fast charging station into a DC-based microgrid
No full textA wide diffusion of fast and ultra-fast stations could affect power quality and the safe operation of distribution networks. Therefore, proper strategies for the optimal management of vehicles, along with the combination of storage systems and renewable sources, is required in order to avoid grid problems. In this context, DC microgrids combining renewables sources, storage systems and electric vehicle stations are demonstrated to foster the integration of these facilities, also allowing optimal exploitation of their functionalities. This study aims at inspecting the effect of electric vehicle fast-charging integration on the optimal operation of a DC-based supply infrastructure and its interaction with the distribution grid. The proposed methodology employs a mixed-integer linear optimization considering economic and technical targets and taking into account charging station cable losses by means of linearization technique. The impact of stochastic optimization and objective combination is further discussed. The procedure is implemented into a DC microgrid integrating a fast-charging station based on realistic facility data, and several scenarios are simulated and compared by means of cost and power loss evaluation