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High-Gain mm-Wave Leaky-Wave/Fabry-Perot Antenna Using Substrate-Integrated Partially Reflective Surfaces
No full textLeaky-wave/Fabry-Perot antennas (LWAs/FPAs) are often implemented by using an air-spacer cavity between the ground plane and partially reflective surfaces (PRSs), which complicates the fabrication process. In this paper, a substrate integrated FPA is investigated by employing a design topology comprising a top PRS printed onto a metal backed low-cost ITERA MT40 dielectric substrate. The top PRS consists of a periodic array of simple patches that are etched by using the standard photolithography method. A pair of metallic strips are introduced in the slotted groundplane to achieve good impedance matching. The proposed FPA achieves a high gain of 11 dBi and shows a simulated impedance matching with an |S11| value of -18 dB at 85 GHz. Finally, the antenna is fabricated and its simulation results are validated through multiple measurements conducted on various samples
Dalla sospensione all’oblio. Come si diventa ex-donatori di sangue
No full textIl Capitolo, che costituisce il cuore del Volume, entra nel merito dell’indagine Re.Atti.Vo. - con Avis Toscana per la donazione di sangue e plasma, ed è interamente dedicata ad approfondirne lo svolgimento e gli esiti – con particolare riferimento al come si diventa “non donatori” e al modo in cui la scelta donatoria (o la sua interruzione) e le relative motivazioni (simboliche e contestuali) influiscono nella definizione dell’identità, di cittadini e volontari. Dopo aver descritto i caratteri teorici e metodologici che hanno contraddistinto il lavoro empirico, Andrea Salvini e Irene Psaroudakis presentano sia i risultati quantitativi, sia le riflessioni e le suggestioni qualitative che sono emerse dalle risposte alle domande aperte incluse nel questionario. I dati raccolti e costruiti nel corso della ricerca sono così sistematizzati in modo da evidenziarne le specificità rispetto alle dinamiche della donazione, e le congruenze rispetto al cambiamento più generale che attraversa la disponibilità dei cittadini all’azione pro-sociale
La socializzazione scolastica alla prova. Individuo, educazione e società
No full textLa scuola è tornata oggi al centro del dibattito pubblico. Laboratorio di partecipazione democratica o luogo di affermazione delle logiche performative di mercato, le istituzioni educative emergono come arene di conflitto in cui si gioca il destino societario, a partire dalle possibili cornici che offrono ai soggetti per fare esperienza di sé, dei legami sociali e delle forme di cittadinanza.
Grazie a un solido impianto teorico e a una ricerca empirica condotta in licei e istituti tecnici e professionali di Toscana e Liguria, il volume esplora il “qui ed ora” dell’esperienza scolastica, dando voce a studenti e insegnanti alle prese con prove e sfide quotidiane.
Analizzando le modalità concrete tramite le quali le singole individualità cercano di comporre le tensioni che attraversano l’intero sistema educativo, il volume restituisce una mappa dinamica delle trasformazioni in atto. Un invito a considerare la scuola non come un’istituzione da difendere o da riformare secondo logiche astratte, ma uno spazio relazionale e conflittuale in cui emergono processi di soggettivazione situata e prendono forma le possibilità del vivere associato
Luce culturale. Emozioni illuminotecniche reinterpretano i valori culturali cinesi nell’era della digitalizzazione.
No full textL’articolo esplora il rapporto tra identità culturale cinese e innovazione tecnologica attraverso il design di sistemi-prodotto illuminotecnici. Si Analizza come la luce, tra simbolismo tradizionale e tecnologie digitali, funga da medium interpretativo di valori e pratiche della cultura cinese. Attraverso casi studio sviluppati in un workshop presso Jiangnan University, si evidenziano pratiche progettuali che fondono patrimonio culturale e interazione, con esperienze immersive e partecipative
Storia della letteratura greca. Dalle origini all'età tardoantica
No full textManuale universitario di storia della letteratura grec
Measurement of the branching fraction, polarization, and time-dependent CP asymmetry in B0 →rho+rho- decays and constraint on the CKM angle phi2
No full textWe present a measurement of the branching fraction and fraction of longitudinal polarization of B0→ρ+ρ- decays, which have two π0's in the final state. We also measure time-dependent CP violation parameters for decays into longitudinally polarized ρ+ρ- pairs. This analysis is based on a data sample containing (387±6)×106 Υ(4S) mesons collected with the Belle II detector at the SuperKEKB asymmetric-energy e+e- collider in 2019-2022. We obtain B(B0→ρ+ρ-)=(2.89-0.22+0.23 -0.27+0.29)×10-5, fL=0.921-0.025+0.024 -0.015+0.017, S=-0.26±0.19±0.08, and C=-0.02±0.12-0.05+0.06, where the first uncertainties are statistical and the second are systematic. We use these results to perform an isospin analysis to constrain the Cabibbo-Kobayashi-Maskawa angle φ2 and obtain two solutions; the result consistent with other Standard Model constraints is φ2=(92.6-4.7+4.5)°
Grounding Methods for Neural-Symbolic AI
No full textA large class of Neural-Symbolic (NeSy) methods employs a machine learner to process the input entities, while relying on a reasoner based on First-Order Logic to represent and process more complex relationships among the entities. A fundamental role for these methods is played by the process of logic grounding, which determines the relevant substitutions for the logic rules using a (sub)set of entities. Some NeSy methods use an exhaustive derivation of all possible substitutions, preserving the full expressive power of the logic knowledge. This leads to a combinatorial explosion in the number of ground formulas to consider and, therefore, strongly limits their scalability. Other methods rely on heuristic-based selective derivations, which are generally more computationally efficient, but lack a justification and provide no guarantees of preserving the information provided to and returned by the reasoner. Taking inspiration from multi-hop symbolic reasoning, this paper proposes a parametrized family of grounding methods generalizing classic Backward Chaining. Different selections within this family allow us to obtain commonly employed grounding methods as special cases, and to control the trade-off between expressiveness and scalability of the reasoner. The experimental results show that the selection of the grounding criterion is often as important as the NeSy method itself
A decision support system (DSS) for estimating tomato growth and mineral uptake in greenhouse soilless system
No full textIn the last decades, there has been intense scientific and technological research aimed at increasing the efficiency of water and fertilizers use in greenhouse crops particularly in soilless cultivation. The approach for managing soilless systems in protected cultivation in a more sustainable way includes the use of decision support systems (DSS) with simulation models to estimate the water and mineral requirements under various growing conditions. The VegSyst model developed at the University o Almeria (Spain) simulates, on a daily basis, the biomass production evapotranspiration, and uptake of major nutrients (N, P, K, Ca, and Mg) in greenhouse soil-grown vegetables. In the present study, the VegSyst model was calibrated and validated in two separate experiments carried out in a glasshouse at the University o Pisa (Italy) with a Tuscan landrace tomato (Pisanello), which is highly appreciated for its taste. Tomato plants were grown in a semi-closed substrate (stone wool) culture. The uptake of N, K and Ca was adequately simulated with the original model parameters determined for soil-grown tomato, while for P and Mg a new calibration was necessary due to the different bioavailability of these mineral nutrients in soil and in artificia substrate. This DSS based on the VegSyst model successfully simulated the biomass and nutrient uptake of key ions, such as N, P, K, Ca and Mg in soilless tomato crops. This approach can help Mediterranean tomato greenhouse producers optimize water and fertilizer usage
Preliminary Experimental Validation of the MARINA ASV for Autonomous Underwater Vehicle Positioning
No full textCooperative strategies between surface and under-water vehicles that address underwater environment challenges are crucial for increasingly complex and long marine operations. Adaptability to these conditions is essential for the unpredictable and harsh scenarios that the marine domain could present. In this context, the team of Robotics, Automation and Autonomous Systems Laboratory (RAASL) of the Department of Information Engineering of the University of Pisa is developing MARINA (Marine Autonomous Robot for Intelligent Networking Applications), a prototype Autonomous Surface Vehicle (ASV) equipped with an Ultra-Short BaseLine (USBL) device to support the navigation of an underwater vehicle. MARINA architecture allows the development and testing of cooperative algorithms designed to support, track, and follow underwater vehicles during missions. The main characteristic of MARINA is the flexible deployment of the USBL, which is mounted on an actuated rod that can be retracted remotely or manually when it is needed, facilitating the transport operation and the installation on land and protecting the acoustic sensor integrity and avoiding impacts with seabed or debris. In this work, the USBL integration and positioning capability were tested in a controlled lake environment. Preliminary results show promising potential for MARINA to support underwater vehicle navigation effectively
Combining Declarative and Linear Programming for Application Management in the Cloud-Edge Continuum
No full textThis work investigates the data-aware multi-service application placement problem in Cloud-Edge settings. We previously introduced EdgeWise, a hybrid approach that combines declarative programming with Mixed-Integer Linear Programming (MILP) to determine optimal placements that minimise operational costs and unnecessary data transfers. The declarative stage pre-processes infrastructure constraints to improve the efficiency of the MILP solver, achieving optimal placements in terms of operational costs, with significantly reduced execution times. In this extended version, we improve the declarative stage with continuous reasoning, presenting EdgeWiseCR, which enables the system to reuse existing placements and reduce unnecessary recomputation and service migrations. In addition, we conducted an expanded experimental evaluation considering multiple applications, diverse network topologies, and large-scale infrastructures with dynamic failures. The results show that EdgeWiseCR achieves up to 65% faster execution compared to EdgeWise, while preserving placement stability under dynamic conditions