211 research outputs found
Unidirectional decomposition method for obtaining exact localized waves solutions totally free of backward components
In this paper we use a unidirectional decomposition capable of furnishing
localized wave pulses, with luminal and superluminal peak velocities, in exact
form and totally free of backward components, which have been a chronic problem
for such wave solutions. This decomposition is powerful enough for yielding not
only ideal nondiffracting pulses but also their finite energy versions still in
exact analytical closed form. Another advantage of the present approach is
that, since the backward spectral components are absent, the frequency spectra
of the pulses do not need to possess ultra-widebands, as it is required by the
usual localized waves (LWs) solutions obtained by other methods. Finally, the
present results bring the LW theory nearer to the real experimental
possibilities of usual laboratories.Comment: 28 pages, 6 figure
Superluminal X-shaped beams propagating without distortion along a coaxial guide
In a previous paper [Phys. Rev. E64 (2001) 066603; e-print physics/0001039],
we showed that localized Superluminal solutions to the Maxwell equations exist,
which propagate down (non-evanescence) regions of a metallic cylindrical
waveguide. In this paper we construct analogous non-dispersive waves
propagating along coaxial cables. Such new solutions, in general, consist in
trains of (undistorted) Superluminal "X-shaped" pulses. Particular attention is
paid to the construction of finite total energy solutions. Any results of this
kind may find application in the other fields in which an essential role is
played by a wave-equation (like acoustics, geophysics, etc.). [PACS nos.:
03.50.De; 41.20;Jb; 83.50.Vr; 62.30.+d; 43.60.+d; 91.30.Fn; 04.30.Nk; 42.25.Bs;
46.40.Cd; 52.35.Lv. Keywords: Wave equations; Wave propagation; Localized
beams; Superluminal waves; Coaxial cables; Bidirectional decomposition; Bessel
beams; X-shaped waves; Maxwell equations; Microwaves; Optics; Special
relativity; Coaxial metallic waveguides; Acoustics; Seismology; Mechanical
waves; Elastic waves; Guided gravitational waves.]Comment: plain LaTeX file (22 pages), plus 15 figures; in press in Phys. Rev.
Deep Learning Based Semantic Segmentation for BIM Model Generation from RGB-D Sensors
RGB-D sensors offer a low-cost and promising solution to streamline the generation of BIM models. This paper introduces a framework designed to automate the creation of detailed and semantically rich BIM models from RGB-D data in indoor environments. The framework leverages advanced computer vision and deep learning techniques to overcome the challenges associated with traditional, labour-intensive BIM modeling methods. The results show that the proposed method is robust and accurate, compared to the high-quality statistic laser scanning TLS. Indeed, 58% of the distances measured between the calculated and the reference point cloud produced by TLS were under 5 cm, and 82% of distances were smaller than 7 cm. Furthermore, the framework achieves 100% accuracy in element extraction. Beyond its accuracy, the proposed framework significantly enhances efficiency in both data acquisition and processing. In contrast to the time-consuming process associated with TLS, our approach remarkably reduces the data collection and processing time by factor of height. This highlights the framework’s substantial improvements in accuracy and efficiency throughout the BIM generation workflows, making it a streamlined and time-effective solution
Interconnect fabrics for multi-core quantum processors: a context analysis
Quantum computing has revolutionized the field of computer science with its extraordinary ability to handle classically intractable problems. To realize its potential, however, quantum computers need to scale to millions of qubits, a feat that will require addressing fascinating yet extremely challenging interconnection problems. In this paper, we provide a context analysis of the nascent quantum computing field from the perspective of communications, with the aim of encouraging the on-chip networks community to contribute and pave the way for truly scalable quantum computers in the decades to come.Authors acknowledge support from the European Research Council (ERC) under GA 101042080 (WINC) and the European Innovation Council (EIC) Pathfinder scheme, GA 101099697 (QUADRATURE).Peer ReviewedPostprint (author's final draft
USE OF KINECT AZURE FOR BIM RECONSTRUCTION: ESTABLISHMENT OF AN ACQUISITION PROTOCOL, SEGMENTATION AND 3D MODELING
With the popularization of RGB-D cameras, access to the third dimension is now possible at low cost. However, these systems have a lower accuracy compared to other technologies such as terrestrial laser scanners (TLS) or mobile laser scanners (MLS). RGB-D cameras have proved their potential for 3D indoor mapping, particularly for Building Information Models reconstruction (Li et al., 2020). This paper aims to investigate the acquisition protocol and propose a method for BIM reconstruction by using an RGB-D camera (Kinect Azure). First, an acquisition protocol is established with the aim of improving the quality of 3D reconstruction of indoor scenes. Different scene cases are considered, namely a single wall, a corridor, a room (with different levels of detail) and two adjacent rooms. After having extracted the best acquisition scenarios for each case of the studied scenes, an image processing is performed for the most complex scenes. Then the 3D reconstruction is performed and the resulting point clouds are subsampled and cleaned. Next, an evaluation of the geometric quality of the 3D reconstruction is performed, by making a comparison between the point clouds from the acquisition protocol (room and corridor) and the reference point clouds from an MLS. The results of this comparison shows that the differences between the two point clouds have an absolute average deviation that doesn’t exceed 4.8mm, which proves that the proposed method has reached competitive accuracy. Finally, segmentation and 3D modeling of the studied scenes are proceeded to extract the BIM objects
From Field to Waste Valorization: A Preliminary Study Exploring the Impact of the Wine Supply Chain on the Phenolic Profile of Three Sardinian Pomace Extracts
The winemaking process generates an annual global production of about 10 million tons of waste consisting of stalks, skin, and seeds. The possible reutilization of wine pomace is strictly linked to its chemical composition. In this preliminary study, three different Sardinian white grapes (Malvasia, Vermentino and Nasco) grown in the same area were evaluated through a whole wine production chain. To reduce environmental impact, all the grapes were treated following the integrated production practice (IPP) strategies. The adopted agronomic methods and the main physico-chemical parameters of the fresh fruits and musts were evaluated. A fully qualitative and quantitative characterization of the phenolic fraction of the pomace extracts was performed by HPLC-DAD after a post-winemaking process. Water and ethanol were utilized as green solvents in the extraction process. Additionally, the entire pomace post-winemaking process was carried out within the winery facilities to reduce energy loss and road transportation. The findings demonstrated that large amounts of beneficial polyphenols are present in pomace extracts, and that the type of grape used, agronomic practices, and winemaking method all influence the quantity and quality of the extracts. The polyphenol concentrations in the Vermentino (28,391.5 +/- 7.0 mg/kg) and Malvasia pomace (11,316.3 +/- 6.5 mg/kg) were found to be the highest and lowest, respectively
Entrapment of citrus limon var. Pompia essential oil or pure citral in liposomes tailored as mouthwash for the treatment of oral cavity diseases
This work aimed at developing a mouthwash based on liposomes loading Citrus limon var. pompia essential oil or citral to treat oropharyngeal diseases. Vesicles were prepared by dispersing phosphatidylcholine and pompia essential oil or citral at increasing amounts (12, 25 and 50 mg/mL) in water. Transparent vesicle dispersions were obtained by direct sonication avoiding the use of organic solvents. Cryogenic transmission electron microscopy (cryo-TEM) confirmed the formation of unilamellar, spherical and regularly shaped vesicles. Essential oil and citral loaded liposomes were small in size (~110 and ~100 nm, respectively) and negatively charged. Liposomes, especially those loading citral, were highly stable as their physico-chemical properties did not change during storage. The formulations were highly biocompatible against keratinocytes, were able to counteract the damages induced in cells by using hydrogen peroxide, and able to increase the rate of skin repair. In addition, liposomes loading citral at higher concentrations inhibited the proliferation of cariogenic bacterium
Extraction, characterization and incorporation of Hypericum scruglii extract in ad hoc formulated phospholipid vesicles designed for the treatment of skin diseases connected with oxidative stress
An extract of Hypericum scruglii, an endangered endemic plant of Sardinia (Italy), was prepared and characterized. It was loaded in special phospholipid vesicles, glycerosomes, which were modified by adding maltodextrin (glucidex) and a polymer (gelatin or hyaluronan). The corresponding liposomes were also prepared and used as reference. The vesicles disclosed suitable physicochemical features for skin delivery. Indeed, their mean diameter ranged from 120 to 160 nm, they were homogeneously dispersed (polydispersity index 0.30), and their zeta potential was highly negative (-45 mV). The vesicle dispersions maintained unchanged characteristics during 60 days of storage, were highly biocompatible, and were able to protect keratinocytes against damages due to oxidative stress induced by treating them with hydrogen peroxide. Vesicles were also capable of promoting cell proliferation and migration in vitro by means of a scratch wound assay. The results confirmed the fruitful delivery of the extract of H. scruglii in glycerosomes modified with glucidex and gelatin and their promising ability for skin protection and treatment
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