Fabry-Perot cavity leaky wave antennas with tunable features for terahertz applications

Terahertz (THz) radiation is a very appealing band of the electromagnetic spectrum due to its practical applications. In this context, the THz generation and manipulation is an essential part of the technological development. The demand of THz antennas is still high because it is already difficult to obtain directive, efficient, planar, low-cost, and easy-to-fabricate THz radiating systems. In this regard, Fabry-Perot cavity leaky-wave antennas are gaining increasing attention at THz, due to their very interesting radiating features: the combination of planar designs with metamaterials and metasurfaces could offer a promising platform for future THz manipulation technologies. In this short review, we focus on different classes of leaky-wave antennas, based on materials with tunable quasi-optical parameters. The possibility of producing directive patterns with particularly good efficiencies, as well as the capability of dynamically reconfiguring their radiating features, are discussed by taking into account the risk of increasing costs and fabrication complexity

Direct Detection of a (Proto)Binary-Disk System in IRAS 20126+4104

We report the direct detection of a binary/disk system towards the high-mass (proto)stellar object IRAS20126+4104 at infrared wavengths. The presence of a multiple system had been indicated by the precession of the outflow and the double jet system detected earlier at cm-wavelengths. Our new K, L' & M' band infrared images obtained with the UKIRT under exceptional seeing conditions on Mauna Kea are able to resolve the central source for the first time, and we identify two objects separated by ~ 0.5'' (850 AU). The K and L' images also uncover features characteristic of a nearly edge-on disk, similar to many low mass protostars with disks: two emission regions oriented along an outflow axis and separated by a dark lane. The peaks of the L' & M' band and mm-wavelength emission are on the dark lane, presumably locating the primary young star. The thickness of the disk is measured to be ~ 850 AU for radii < 1000 AU. Approximate limits on the NIR magnitudes of the two young stars indicate a high-mass system, although with much uncertainty. These results are a demonstration of the high-mass nature of the system, and the similarities of the star-formation process in the low-mass and high-mass regimes viz. the presence of a disk-accretion stage. The companion is located along the dark lane, consistent with it being in the equatorial/disk plane, indicating a disk-accretion setting for massive, multiple, star-formation.Comment: 12 pages, 3 figures (1 pseudo colour), 1 table; colour figure replaced with jpg file; to be published in ApJL; (back after temoprary withdrawal due to non-scientific reasons.

HIRESSS: a physically based slope stability simulator for HPC applications

HIRESSS (&lt;b&gt;HI&lt;/b&gt;gh &lt;b&gt;RE&lt;/b&gt;solution &lt;b&gt;S&lt;/b&gt;lope &lt;b&gt;S&lt;/b&gt;tability &lt;b&gt;S&lt;/b&gt;imulator) is a physically based distributed slope stability simulator for analyzing shallow landslide triggering conditions in real time and on large areas using parallel computational techniques. The physical model proposed is composed of two parts: hydrological and geotechnical. The hydrological model receives the rainfall data as dynamical input and provides the pressure head as perturbation to the geotechnical stability model that computes the factor of safety (FS) in probabilistic terms. The hydrological model is based on an analytical solution of an approximated form of the Richards equation under the wet condition hypothesis and it is introduced as a modeled form of hydraulic diffusivity to improve the hydrological response. The geotechnical stability model is based on an infinite slope model that takes into account the unsaturated soil condition. During the slope stability analysis the proposed model takes into account the increase in strength and cohesion due to matric suction in unsaturated soil, where the pressure head is negative. Moreover, the soil mass variation on partially saturated soil caused by water infiltration is modeled. &lt;br&gt;&lt;br&gt; The model is then inserted into a Monte Carlo simulation, to manage the typical uncertainty in the values of the input geotechnical and hydrological parameters, which is a common weak point of deterministic models. The Monte Carlo simulation manages a probability distribution of input parameters providing results in terms of slope failure probability. The developed software uses the computational power offered by multicore and multiprocessor hardware, from modern workstations to supercomputing facilities (HPC), to achieve the simulation in reasonable runtimes, compatible with civil protection real time monitoring. &lt;br&gt;&lt;br&gt; A first test of HIRESSS in three different areas is presented to evaluate the reliability of the results and the runtime performance on large areas

Combination of rainfall thresholds and susceptibility maps for dynamic landslide hazard assessment at regional scale

We propose a methodology to couple rainfall thresholds and susceptibility maps for dynamic landslide hazard assessment at regional scale. Both inputs are combined in a purposely-built hazard matrix to get a spatially and temporally variable definition of landslide hazard: while statistical rainfall thresholds are used to accomplish a temporal forecasting with very coarse spatial resolution, landslide susceptibility maps provide static spatial information about the probability of landslide occurrence at fine spatial resolution. The test site is the Northern part of Tuscany (Italy), where a recent landslide susceptibility map and a set of recently updated rainfall thresholds are available. These products were modified and updated to meet the requirements of the proposed procedure: the susceptibility map was reclassified and the threshold set was expanded defining additional thresholds. The hazard matrix combines three susceptibility classes (S1, low susceptibility; S2 medium susceptibility; S3 high susceptibility) and three rainfall rate classes (R1, R2, R3), defining five hazard classes, from H0 (null hazard) to H4 (high hazard). A key passage of the procedure is the appropriate calibration and validation of the matrix, letting the hazard classes have a precise meaning in terms of expected consequences and hazard management. The employ of the proposed procedure in a regional warning system brings two main advantages: (i) it is possible to better hypothesize when and where landslide are expected and with which hazard degree, thus fostering a more effective hazard and risk management (e.g., setting priorities of intervention); (ii) the spatial resolution of the regional scale warning system is markedly refined because from time to time the areas where landslides are expected represent only a fraction of the alert zone

Shallow landslides and rockfalls velocity assessment at regional scale: a methodology based on a morphometric approach

Velocity is one of the most important parameters to evaluate the damaging potential of a mass movement, but its assessment, especially for extremely rapid landslides, is a complex task. In the literature, several models to assess mass movement velocity exist, but they usually require many detailed parameters, and therefore, they are applicable only to a single slope and not usable for regional-scale analyses. This study aims to propose a simple morphometric methodology, based on the spatialisation of the Energy Line method, to determine the velocity of shallow landslides and rockfalls at a regional scale. The proposed method requires a limited amount of input data (landslide perimeters and a digital elevation model), and its application can be carried out using GIS software and a Matlab code. The test area of this work is the Valle d’Aosta Region (Northern Italy), selected due to its peculiar geological and geomorphological setting that makes this region susceptible to the occurrence of both shallow landslides and rockfalls. Since measured velocity values for rockfalls and shallow landslides were not available, the results obtained with the proposed method have been validated through the implementation of a model in the literature, namely the Gravitational Process Path (GPP) model, for some selected landslides

DESAIN SISTEM DOKUMENTASI TUGAS AKHIR OTOMATIS BERBASIS PENGOLAHAN CITRA DIGITAL HASIL AKUISISI WEBCAM DENGAN MENGGUNAKAN JST BACKPROPAGATION

ABSTRAKSI: Dengan meningkatnya jumlah mahasiswa yang lulus saat ini, maka semakin banyak pula tugas akhir mahsiswa yang dibuat. Ini mendorong dibuatnya suatu sistem yang dapat mendokumentasikan buku – buku tugas akhir mahasiswa secara cepat dan sederhana. Sistem dokumentasi yang dilakukan di perpustakaan fakultas teknik elektro dan komunikasi IT Telkom untuk tugas akhir ini adalah dengan cara manual, yaitu dengan mengetikkan data yang ada pada buku tugas akhir tersebut melalui keyboard.Dalam tugas akhir ini akan dibuat suatu sistem untuk mendokementasikan buku – buku tugas akhir mahasiswa IT Telkom. Proses pendokumentasian tersebut dilakukan melalui pengenalan pola karakter alfabet dari suatu citra dari akuisisi webcam dengan menggunakan jaringan syaraf tiruan Backpropagation. JST Backpropagation adalah suatu jaringan supervisi (jaringan syaraf yang membutuhkan target) yang memiliki karateristik multilayer dan memiliki fasa propagasi maju dan propagasi mundur dalam melatih polanya.Dalam pengujiannya citra yang diambil berasal dari webcam dengan resolusi 640x480. Pengujian terhadap sistem dilakukan dengan pencarian fungsi aktivasi terbaik untuk mengoptimalkan JST, kemudian menguji sistem terhadap empat bentuk font, dan empat format ukuran tulisan, menguji terhadap buku tugas akhir dengan font yang dianggap paling baik dengan mengubah parameter threshold preprocessing.Dalam pengujian kehandalan sistem dari huruf yang telah diekstrak cirinya tersebut terlihat bahwa font yang cocok digunakan terhadap sistem ini adalah arial dengan akurasi hingga 89% dengan nilai threshold rata – rata yang menghasilkan akurasi tertinggi berada pada nilai 100.Kata Kunci : JST, backpropagation, image processing,ekstraksi ciriABSTRACT: With the increasing number of students who graduated today, so more final task is created. This push made a system that can document the books quickly and simply. Documentation system that is in the library faculty of electrical engineering and communications IT Telkom is manually, by typing the data from the book via the keyboard.In this final task will be made documentation system for final task book IT Telkom students. Documentation process is done through pattern recognition alphabet characters from a webcam image acquisition by using artificial neural networks Backpropagation. ANN Backpropagation is a supervised network (neural networks that require targets) that have characteristic multilayer and a propagation phase propagation forward and backward in the training pattern.In a test image taken from a webcam with 640x480 resolution. Testing of the system is done by searching the best activation function to optimize the ANN, and then test the system against the four forms of fonts, and text size of four formats, testing the book with the final task the font is best considered by changing the threshold preprocessing parameter.In the reliability testing of the system that has been extracted characters can be seen that the character that font matches used for this system is the arial with an accuracy up to 89% with the average threshold value - the average yield at the highest accuracy value 100.Keyword: JST, backpropagation, image processing, feature extractio