Considerations about learning Word2Vec

AbstractDespite the large diffusion and use of embedding generated through Word2Vec, there are still many open questions about the reasons for its results and about its real capabilities. In particular, to our knowledge, no author seems to have analysed in detail how learning may be affected by the various choices of hyperparameters. In this work, we try to shed some light on various issues focusing on a typical dataset. It is shown that the learning rate prevents the exact mapping of the co-occurrence matrix, that Word2Vec is unable to learn syntactic relationships, and that it does not suffer from the problem of overfitting. Furthermore, through the creation of an ad-hoc network, it is also shown how it is possible to improve Word2Vec directly on the analogies, obtaining very high accuracy without damaging the pre-existing embedding. This analogy-enhanced Word2Vec may be convenient in various NLP scenarios, but it is used here as an optimal starting point to evaluate the limits of Word2Vec

Optimized Realization of Bayesian Networks in Reduced Normal Form using Latent Variable Model

Bayesian networks in their Factor Graph Reduced Normal Form (FGrn) are a powerful paradigm for implementing inference graphs. Unfortunately, the computational and memory costs of these networks may be considerable, even for relatively small networks, and this is one of the main reasons why these structures have often been underused in practice. In this work, through a detailed algorithmic and structural analysis, various solutions for cost reduction are proposed. An online version of the classic batch learning algorithm is also analyzed, showing very similar results (in an unsupervised context); which is essential even if multilevel structures are to be built. The solutions proposed, together with the possible online learning algorithm, are included in a C++ library that is quite efficient, especially if compared to the direct use of the well-known sum-product and Maximum Likelihood (ML) algorithms. The results are discussed with particular reference to a Latent Variable Model (LVM) structure.Comment: 20 pages, 8 figure

diabetes in active tuberculosis in low income countries to test or to take care

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L'Ultimo capitolo della tradizionale produzione ceramica di Barrama (Tunisia)

Molti chiari segnali indiziano la fine della produzione della caratteristica ceramica di Barrama, presso Bargou, nel Governatorato tunisino di Siliana. La forma di artigianato familiare, adottata dall’intero villaggio di Barrama come fonte primaria di introiti, ha faticosamente convissuto con i primi decenni di industrializzazione, ma non regge all’impatto dell’economia globale, avviandosi verso l’estinzione, già toccata in sorte a quelli che furono fiorentissimi rami di produzione artigianale nei paesi europei, tra cui quello dei coltelli tascabili, dal quale vengono tratte diverse situazioni di confronto. Mentre si impongono contenitori fabbricati con materiali diversi dalla ceramica di impasto in conseguenza della diffusione della plastica, del metallo e della ceramica industriale, nel villaggio si assiste all’ibridazione delle forme tradizionali, all’introduzione di forme estranee alla tradizione locale, allo stimolo, anche tramite scuole, dello sviluppo della creatività individuale. Nel contributo si illustrano, pertanto, il repertorio delle forme tradizionali e alcuni dei nuovi prodotti, destinati certo a più breve fortuna e si auspica infine una rinascita di questa come di altre produzioni artigianali estinte. There are many indications of the end of the typical pottery manufacture of Barrama, a village near Bargou (Siliana, Tunisia). The traditional manufacture, originally a primary economic resource of the village, which scarcely survived the beginnings of industrialization, predictably failed to resist globalisation, like other European-based handicrafts such as pocket knife production (from which, several comparisons are discussed). While vessels made from various alternative materials (plastic, metal and industrial ceramics) expanded, we also note the hybridization of traditional pottery shapes, the introduction of non-traditional shapes and the development of other forms of individual creativity. In this article, we illustrate both the range of traditional forms and some of the new forms which we anticipate will be of short duration, before, we hope, a resurgence of the traditional forms

Osservazioni sulla pesca in età preistorica. Attrezzature, catture e preparazioni

EnThe poor conservation of the fish in prehistoric contexts and the difficulties of identification and collection of the remains greatly limit the possibility to trace a satisfactory drawing of alimentary use of marine and fresh water fish. Very fragmentary is the documentation of the instruments, of which remain only a few non-perishable parts, and then the activities that were put in place for the procurement of fish.Nevertheless, there are information to say that fishing practices have been, since the end of the Pleistocene, important part in the economies of the groups settled in river or lakes basins, or along the sea coast and we can reconstruct, in a largely hypothetical way, a part of fish capture methods.ItLa scarsa conservazione della fauna ittica nei contesti preistorici e le difficoltà dell’individuazione e del prelievo dei resti limitano notevolmente la possibilità di ricostruire un quadro soddisfacente dell’utilizzo alimentare dei pesci di mare e di acqua dolce.Molto frammentaria è la documentazione dello strumentario, di cui si trovano solo alcune parti non deperibili, e quindi delle attività poste in atto per il procacciamento del pesce.Nonostante ciò vi sono indizi per affermare che le pratiche alieutiche sono state, già dalla fine del Pleistocene, parte importante nelle economie dei gruppi insediati presso bacini fluviali, lacustri o sulla costa marina e si può ricostruire in via largamente ipotetica una parte dei metodi di cattura delle prede ittiche

Rotational arherectomy in the distal left anterior descending coronary artery through an internal mammary artery graft.

We report the case of a 53-year-old white man who began complaining of dyspnoea and angina 19 months after coronary artery bypass graft surgery. Coronary angiography revealed the presence of a long and critical stenosis in the native left anterior descending coronary artery, shortly after distal anastomosis of the left internal mammary artery. After failed predilatations with standard or cutting balloons, we successfully used the rotablator system, which allowed us to implant a bare-metal stent in the native left anterior descending coronary artery. However, stent deployment caused long linear graft dissection, which was reduced by drug-eluting stent implantation in the proximal and distal segments of the left internal mammary artery

Parachute emergency landing simulation and enhanced composite material characterization for General Aviation aircraft

General Aviation (GA) aircraft crashworthiness of the vehicle when it hits the ground after the parachute deployment is an important issue. The current dynamic emergency landing regulation (CS 23.562) defines the maximum human tolerant accelerations under both vertical and horizontal directions. This article aims to compare two different aircraft configurations: metal low-wing and composite high-wing ones. Both are two-seats and single-engine GA aircraft. The purpose of the analysis is to check whether the seats and restraint systems met human injury tolerance standards and to determine the possible impact on passengers in the cabin space due to shock loads. Finite element analysis of the fuselage sections for both configurations is performed using the commercial LS-Dyna solver. An extensive campaign of experimental tests has been performed on the composite samples for tuning and validating the model and to find the transition from an undamaged up to totally collapsed sample. The material of the composite fuselage has been characterized through experimental tests. The adopted material model has been refined to match with the performed experimental analysis, allowing high-fidelity modeling. A parametric analysis has been performed to determine the optimal impact angle in terms of lumbar injuries and loads transmitted by the seat belt due to aircraft contact with the ground, thereby increasing the level of safety. The investigations carried out may be an important indicator of the design of the parachute system