624 research outputs found

    Sensor Deployment for Network-like Environments

    Full text link
    This paper considers the problem of optimally deploying omnidirectional sensors, with potentially limited sensing radius, in a network-like environment. This model provides a compact and effective description of complex environments as well as a proper representation of road or river networks. We present a two-step procedure based on a discrete-time gradient ascent algorithm to find a local optimum for this problem. The first step performs a coarse optimization where sensors are allowed to move in the plane, to vary their sensing radius and to make use of a reduced model of the environment called collapsed network. It is made up of a finite discrete set of points, barycenters, produced by collapsing network edges. Sensors can be also clustered to reduce the complexity of this phase. The sensors' positions found in the first step are then projected on the network and used in the second finer optimization, where sensors are constrained to move only on the network. The second step can be performed on-line, in a distributed fashion, by sensors moving in the real environment, and can make use of the full network as well as of the collapsed one. The adoption of a less constrained initial optimization has the merit of reducing the negative impact of the presence of a large number of local optima. The effectiveness of the presented procedure is illustrated by a simulated deployment problem in an airport environment

    A Composite Index to Measure the Italian "Enological Vocation"

    Get PDF
    Abstract The Italian wine industry is going through, during a general economic crisis, a period of strong growth and expansion in the world markets. The quality of products, characterized by tradition and innovation, has defeated the involution of the Italian entrepreneurial system. The variety of wines produced represents the peculiarities of the Italian territory. The aim of this paper is to measure a multidimensional phenomenon, the "Enological vocation" of the Italian provinces, through the use of a composite index. The results highlight both areas of the territory for which it is known the strong vocation and less known areas where you need to do further investigation

    A BRIEF PRACTICAL-GUIDE FOR L2-TEACHERS: K-2 AMERICAN CHILDREN LEARN ITALIAN

    Get PDF
    This paper aims to provide some good techniques and strategies L2 teachers may adopt in order to encourage greater involvement in younger children (from kindergarten to second grade). These techniques are theoretical-guided and support the idea that the whole person is involved in the learning activity. Therefore, the teaching experience becomes a multidimensional approach: it can feature creative tasks, like painting and drawing, as well as practical ones, such as cooking and reciting; static activities, such as singing, as well as active ones, like jumping and dancing; memory tasks, such as rote repetition, as well as “out the blue” tasks, such as shouting new words out; make use of traditional support materials, such as paper, as well as modern ones, such as videos; etc. This multidimensional approach leads to excellent results in L2 acquisition and it will be exemplified by a project where Italian L2 was taught in a school in the United States.   Una breve guida pratica per insegnanti di L2: come i bambini americani in età prescolare imparano l’italiano Il presente lavoro mira a fornire alcune buone tecniche e strategie che gli insegnanti di L2 possono adottare per ottenere un migliore e più forte coinvolgimento dello studente nei primi livelli di scolarità (dalla scuola materna alla seconda elementare). Tali tecniche sono guidate dalla teoria e sostengono l’idea che l’intera persona sia coinvolta nell’attività di apprendimento. Pertanto, l’esperienza di insegnamento deve affrontare un approccio multidimensionale: si dovrebbero adottare compiti creativi, come dipingere e disegnare, al pari di quelli pratici, come cucinare e recitare; si dovrebbero adottare attività come cantare, così come attività motorie, come saltare e ballare; compiti di memoria, come ripetere a memoria, così come attività di improvvisazione, ad es. gridare nuove parole; infine si dovrebbero adottare, accanto a risorse moderne come i video, materiali di supporto tradizionali, come la carta, ecc. Un tale approccio multidimensionale ottiene ottimi risultati nell'acquisizione della L2 come dimostra il progetto qui esposto in cui l’italiano è stato insegnato come L2 in una scuola degli Stati Uniti

    Generalized Holographic Principle, Gauge Invariance and the Emergence of Gravity a la Wilczek

    Get PDF
    We show that a generalized version of the holographic principle can be derived from the Hamiltonian description of information flow within a quantum system that maintains a separable state. We then show that this generalized holographic principle entails a general principle of gauge invariance. When this is realized in an ambient Lorentzian space-time, gauge invariance under the Poincare group is immediately achieved. We apply this pathway to retrieve the action of gravity. The latter is cast a la Wilczek through a similar formulation derived by MacDowell and Mansouri, which involves the representation theory of the Lie groups SO(3,2) and SO(4,1).Comment: 26 pages, 1 figur

    SABSPV - A Monte Carlo Integrator for Small-Angle Bhabha Scattering

    Get PDF
    SABSPV is a code designed to perform a theoretical evaluation of small-angle Bhabha scattering cross sections by suitably matching fixed-order perturbative calculations and structure-function techniques. The implementation of realistic experimental triggering conditions is achieved by using Monte Carlo integration.Comment: 12 pages, LaTeX, no figures, no macro

    Asymmetries in extraction from nominal copular sentences: A challenging case study for NLP tools

    Get PDF
    In this paper we discuss two types of nominal copular sentences (Canonical and Inverse, Moro 1997) and we demonstrate how the peculiarities of these two configurations are hardly considered by standard NLP tools that are currently publicly available. Here we show that example-based MT tools (e.g. Google Translate) as well as other NLP tools (UDpipe, LinguA, Stanford Parser, and Google Cloud AI API) fail in capturing the critical distinctions between the two structures in the end producing both wrong analyses and, possibly as a consequence of a non-coherent (or missing) structural analysis, incorrect translations in the case of MT tools. To support the proposed analysis, we present also an empirical study showing that native speakers are indeed sensitive to the critical distinctions. This poses a sharp challenge for NLP tools that aim at being cognitively plausible or at least descriptively adequate (Chowdhury & Zamparelli 2018)

    Assessment of muscle fatigue during isometric contraction using autonomic nervous system correlates

    Get PDF
    Muscle fatigue is a complex phenomenon that results in a reduction of the maximal voluntary force. Measuring muscle fatigue can be a challenging task that may involve the use of intramuscular electrodes (i.e., intramuscular electromyography (EMG)) or complex acquisition techniques. In this study, we propose an alternative non-invasive methodology for muscle fatigue detection relying on the analysis of two autonomic nervous system (ANS) correlates, i.e., the electrodermal activity (EDA) and heart rate variability (HRV) series. Based on standard surface EMG analysis, we divided 32 healthy subjects performing isometric biceps contraction into two groups: a fatigued group and a non-fatigued group. EDA signals were analyzed using the recently proposed cvxEDA model in order to derive phasic and tonic components and extract effective features to study ANS dynamics. Furthermore, HRV series were processed to derive several features defined in the time and frequency domains able to estimate the cardiovascular autonomic regulation. A statistical comparison between the fatigued and the non-fatigued groups was performed for each ANS feature, and two EDA features, i.e., the tonic variability and the phasic response rate, showed significant differences. Moreover, a pattern recognition procedure was applied to the combined EDA-HRV feature-set to automatically discern between fatigued and non-fatigued subjects. The proposed SVM classifier, following a recursive feature elimination stage, exhibited a maximal balanced accuracy of 83.33%. Our results demonstrate that muscle fatigue could be identified in a non-invasive fashion through effective EDA and HRV processing

    Can endometrial arylsulfatase A activity predict the onset of endometrial polyps over the years?

    Get PDF
    PURPOSE: To assess if arylsulfatase A activity (ASA) and sulfatide (SL) concentration in the human endometrium can be predictive of the development of endometrial polyps over the years, since ASA activity reflects the endometrial sensitivity to hormones. METHODS: ASA activity and SL concentration were determined by biochemical procedures on endometrial samples collected between 1990 and 1994 in non-menopausal women. These women underwent a new endometrial sampling following the clinical indication some years after the first endometrial sampling. The histological assessment of the second endometrial specimens found four patients with normal endometrial pattern and 10 patients with one or more endometrial polyps. ASA activity/years elapsed and SL concentration/years elapsed were compared using two tailed Mann-Whitney test for unpaired data between patients with normal pattern and patients with endometrial polyps. RESULTS: Median ASA activities were 2.62 (normal pattern) versus 1.85 (endometrial polyps) nmol hydrolized substrate/min. Median activity/years elapsed is higher in patients with second endometrial sample presenting normal pattern (p=0.006) and median SL concentration/years elapsed does not differ significantly among groups, even if median SL concentration seems to be higher in patients who subsequently developed polyps (1031 µg/g of fresh tissue versus 341,5 µg/g of fresh tissue). CONCLUSIONS: ASA activity can predict the onset of endometrial polyps over the years. OBJETIVO: Avaliar se a atividade da arilsulfatase A (ASA) e a concentração de sulfatida (SL) no endométrio humano pode ser preditivo em relação ao desenvolvimento de pólipos endometriais ao longo dos anos, posto que atividade da ASA reflete a sensibilidade do endométrio aos hormônios. MÉTODOS: A atividade da ASA, assim como a concentração de SL, foi determinada por meio de procedimentos bioquímicos em amostras de endométrio coletadas entre 1990 e 1994, em mulheres que não se encontravam na menopausa. Essas mulheres foram submetidas a uma nova amostragem endometrial após indicação clínica alguns anos depois da primeira amostragem endometrial. A avaliação histológica dos segundos espécimes endometriais permitiu identificar quatro pacientes com padrão endometrial normal e 10 com um ou mais pólipos endometriais. A atividade da ASA/anos depois e a concentração de SL/anos depois foram comparadas, utilizando o teste bilateral U de Mann-Whitney para dados não pareados entre as pacientes com padrão normal e as pacientes com pólipos endometriais. RESULTADOS: A ativitade da ASA foi 2,62 (padrão normal) em comparação com 1,85 (endometrial pólipos) de substrato hidrolisado/min. A atividade da ASA/anos depois é maior em pacientes com segunda amostra endometrial a apresentarem um padrão normal (p=0,006), e a concentração mediana de SL/anos depois não difere de forma significativa entre os grupos, apesar de a concentração mediana de SL parecer maior em pacientes que posteriormente desenvolveram pólipos (1031 µg/g de tecido fresco em comparação com 341,5 µg/g de tecido fresco). CONCLUSÕES: A atividade da ASA pode prever a aparição de pólipos endometriais ao longo dos anos
    corecore