262 research outputs found

    School Choice and Quality

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    The 1993 Survey of Household Income and Wealth, a representative survey of the Italian population covering 24,000 individuals, reports detailed information on children's attendance of public and private schools and parents' assessments of the quality of public schools in the city of residence. The survey also provides detailed information on the household's demographic structure, income and parents' education. The empirical analysis indicates that the quality of schools is one of the driving factors in the choice between private and public schools. The results are robust with respect to the particular quality indicator used and the presence of fixed provincial effects

    Finding integral points on algebraic varieties

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    The Vojta’s conjecture establishes geometrical conditions on the degeneracy of the set of S-integral points for an algebraic variety. The goal of the thesis is to prove that for certain algebraic varieties for which such conditions are not verified the set of S-integral points is Zariski-dense. Some effective methods in this respect has been developed by Beukers in his paper “Ternary form Equations” , in which he proved the density of integral solutions of some homogeneous diophantine equations. Following such ideas, the work of the thesis consists on finding the density of S-integral points on some varieties for which it is not known at the moment, imposing the needed arithmetical and geometrical conditionsope

    School Choice and Quality

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    The 1993 Survey of Household Income and Wealth, a representative survey of the Italian population covering 24,000 individuals, reports detailed information on children attendance of public and private schools and parents? self-assessment of the quality of public schools in the city of residence. The survey also provides detailed information on the household demographic structure, income and parents? education. The empirical analysis indicates that the quality of schools is one of the driving factors in the choice between private and public schools. The results are robust with respect to the particular quality indicator used and the presence of provincial fixed effects

    A New Method for Geometric Interpretation of Elliptic Curve Discrete Logarithm Problem

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    In this paper, we intend to study the geometric meaning of the discrete logarithm problem defined over an Elliptic Curve. The key idea is to reduce the Elliptic Curve Discrete Logarithm Problem (EC-DLP) into a system of equations. These equations arise from the interesection of quadric hypersurfaces in an affine space of lower dimension. In cryptography, this interpretation can be used to design attacks on EC-DLP. Presently, the best known attack algorithm having a sub-exponential time complexity is through the implementation of Summation Polynomials and Weil Descent. It is expected that the proposed geometric interpretation can result in faster reduction of the problem into a system of equations. These overdetermined system of equations are hard to solve. We have used F4 (Faugere) algorithms and got results for primes less than 500,000. Quantum Algorithms can expedite the process of solving these over-determined system of equations. In the absence of fast algorithms for computing summation polynomials, we expect that this could be an alternative. We do not claim that the proposed algorithm would be faster than Shor's algorithm for breaking EC-DLP but this interpretation could be a candidate as an alternative to the 'summation polynomial attack' in the post-quantum era

    A post-quantum key exchange protocol from the intersection of quadric surfaces

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    In this paper we present a key exchange protocol in which Alice and Bob have secret keys given by quadric surfaces embedded in a large ambient space by means of the Veronese embedding and public keys given by hyperplanes containing the embedded quadrics. Both of them reconstruct the isomorphism class of the intersection which is a curve of genus 1, which is uniquely determined by the jj-invariant. An eavesdropper, to find this jj-invariant, has to solve problems which are conjecturally quantum resistant.Comment: 20 pages, no figure

    Elliptic Curves of Nearly Prime Order

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    Constructing an elliptic curve of prime order has a significant role in elliptic curve cryptography. For security purposes, we need an elliptic curve of almost prime order. In this paper, we propose an efficient technique to generate an elliptic curve of nearly prime order. In practice, this algorithm produces an elliptic curve of order 2 times a prime number. Therefore, these elliptic curves are appropriate for practical uses. Presently, the most known working algorithms for generating elliptic curves of prime order are based on complex multiplication. The advantages of the proposed technique are: it does not require a deep mathe- matical theory, it is easy to implement in any programming language and produces an elliptic curve with a remarkably simple expression

    A post-quantum signature scheme from the secant variety of the Grassmannian

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    In this paper we present a signature scheme based on the difficulty of finding a point in a shifted Grassmannian variety or on its secant variety from a knowledge of its defining polynomials. An advantage of using the secant variety of the Grassmannian is that it is defined by sparse cubic equations, which are in general more difficult to solve than quadratic ones, thereby reducing the size of the public key

    Online Fall Detection using Recurrent Neural Networks

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    Unintentional falls can cause severe injuries and even death, especially if no immediate assistance is given. The aim of Fall Detection Systems (FDSs) is to detect an occurring fall. This information can be used to trigger the necessary assistance in case of injury. This can be done by using either ambient-based sensors, e.g. cameras, or wearable devices. The aim of this work is to study the technical aspects of FDSs based on wearable devices and artificial intelligence techniques, in particular Deep Learning (DL), to implement an effective algorithm for on-line fall detection. The proposed classifier is based on a Recurrent Neural Network (RNN) model with underlying Long Short-Term Memory (LSTM) blocks. The method is tested on the publicly available SisFall dataset, with extended annotation, and compared with the results obtained by the SisFall authors.Comment: 6 pages, ICRA 201

    Transport certifications of cattle moved from France to Southern Italy and Greece: do they comply with Reg. EC 1/2005?

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    Movements of livestock across the Member States is monitored using the Trade Control and Expert System (TRACES), a web-based veterinarian certification tool. This study aimed to evaluate the criticalities of this tracing system and the most frequent non-conformities in their compilation. TRACES of cattle (n = 320) departed from France and arriving or transiting across Puglia (Italy) in 2019 (n = 199) and 2020 (n = 121) were analysed. The distribution arriving in Italy and Greece did not vary between the 2 years. The majority of the bovine (53.4%) were medium-sized cattle transported for fattening with a median body weight of 410 kg. However, almost half of the TRACES did not report correctly the total expected loaded weight or the available space, so for them, it was impossible to calculate and double-check whether the minimal space allowance was respected. Long journeys must include a resting stop after the first 14 h, however, 20.9% of the examined and declared stops did not comply with it. Finally, comparing the expected declared journey duration with a calculated one (dividing travel distance by an average speed of 70 km/h, adding 1 h for loading and unloading, and 1 h or 24 h for resting stops), we found that only 30.6% of the journey durations were congruent. The irregularities resulted associated with consignors and transporters (p < .05). Overall, the proportion of mistakes and non-compliance suggest that there is a need to improve the current practice to enhance animal welfare during transportation
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