178,288 research outputs found
Can Blockchains and Linked Data Advance Taxation
No full textPermissioned distributed ledgers (permissioned blockchains) supporting smart contracts that automatically adjust accounts and coordinate records among multiple parties, present a valid platform opportunity for establishing a fully digital tax regime. We propose a permissioned blockchain-based system aimed at eliminating some of the losses that tax authorities globally are currently struggling with. These multi-billion flaws manifest themselves as the tax gap, or the inability to collect the full amount that is owed by a given entity to a particular authority. Illegitimate or inefficient tax operations could be prevented with a global suite of smart contracts deployed on top of a consortium distributed ledger with on-chain governance. We also introduce the vision for a VAT Invoice 2.0 modelled as a Linked Data document. A tax reference generated by a smart contract would allow anyone with the right permissions to immediately investigate the entire commercial chain for any taxable item on an ontology-based tax document
Reto R. Bezzola. — Les origines et la formation de la littérature courtoise en Occident (500-1200). 3e p. : La société courtoise: littérature de cour et littérature courtoise
No full textMicha Alexandre. Reto R. Bezzola. — Les origines et la formation de la littérature courtoise en Occident (500-1200). 3e p. : La société courtoise: littérature de cour et littérature courtoise. In: Cahiers de civilisation médiévale, 7e année (n°26), Avril-juin 1964. pp. 187-189
Reto R. Bezzola. — Les origines et la formation de la littérature courtoise en Occident (500-1200) ; 2e partie, La société féodale et la transformation de la littérature de cour.
No full textMicha Alexandre. Reto R. Bezzola. — Les origines et la formation de la littérature courtoise en Occident (500-1200) ; 2e partie, La société féodale et la transformation de la littérature de cour.. In: Cahiers de civilisation médiévale, 5e année (n°18), Avril-juin 1962. pp. 205-207
Dominance Product and High-Dimensional Closest Pair under L_infty
No full textGiven a set of points in \mathbb{R}^d, the Closest Pair problem is to find a pair of distinct points in S at minimum distance.
When d is constant, there are efficient algorithms that solve this problem, and fast approximate solutions for general d.
However, obtaining an exact solution in very high dimensions seems to be much less understood.
We consider the high-dimensional L_\infty Closest Pair problem, where d=n^r for some r > 0, and the underlying metric is L_\infty.
We improve and simplify previous results for L_\infty Closest Pair, showing that it can be solved by a deterministic strongly-polynomial algorithm that runs in O(DP(n,d)\log n) time, and by a randomized algorithm that runs in O(DP(n,d)) expected time, where DP(n,d) is the time bound for computing the dominance product for n points in \mathbb{R}^d.
That is a matrix D, such that
D[i,j] = \bigl| \{k \mid p_i[k] \leq p_j[k]\} \bigr|; this is the number of coordinates at which p_j dominates p_i.
For integer coordinates from some interval [-M, M], we obtain an algorithm that runs in \tilde{O}\left(\min\{Mn^{\omega(1,r,1)},\, DP(n,d)\}\right) time, where \omega(1,r,1) is the exponent of multiplying an n \times n^r matrix by an n^r \times n matrix.
We also give slightly better bounds for DP(n,d), by using more recent rectangular matrix multiplication bounds.
Computing the dominance product itself is an important task, since it is applied in many algorithms as a major black-box ingredient, such as algorithms for APBP (all pairs bottleneck paths),
and variants of APSP (all pairs shortest paths)
On Rich Points and Incidences with Restricted Sets of Lines in 3-Space
No full textLet L be a set of n lines in ℝ³ that is contained, when represented as points in the four-dimensional Plücker space of lines in ℝ³, in an irreducible variety T of constant degree which is non-degenerate with respect to L (see below). We show:
(1) If T is two-dimensional, the number of r-rich points (points incident to at least r lines of L) is O(n^{4/3+ε}/r²), for r ⩾ 3 and for any ε > 0, and, if at most n^{1/3} lines of L lie on any common regulus, there are at most O(n^{4/3+ε}) 2-rich points. For r larger than some sufficiently large constant, the number of r-rich points is also O(n/r).
As an application, we deduce (with an ε-loss in the exponent) the bound obtained by Pach and de Zeeuw [J. Pach and F. de Zeeuw, 2017] on the number of distinct distances determined by n points on an irreducible algebraic curve of constant degree in the plane that is not a line nor a circle.
(2) If T is two-dimensional, the number of incidences between L and a set of m points in ℝ³ is O(m+n).
(3) If T is three-dimensional and nonlinear, the number of incidences between L and a set of m points in ℝ³ is O (m^{3/5}n^{3/5} + (m^{11/15}n^{2/5} + m^{1/3}n^{2/3})s^{1/3} + m + n), provided that no plane contains more than s of the points. When s = O(min{n^{3/5}/m^{2/5}, m^{1/2}}), the bound becomes O(m^{3/5}n^{3/5}+m+n).
As an application, we prove that the number of incidences between m points and n lines in ℝ⁴ contained in a quadratic hypersurface (which does not contain a hyperplane) is O(m^{3/5}n^{3/5} + m + n).
The proofs use, in addition to various tools from algebraic geometry, recent bounds on the number of incidences between points and algebraic curves in the plane
Relationship of Inglehart's and Schwartz's value dimensions revisited
No full textThis study examines the relationship between Inglehart's and Schwartz's value dimensions-both at the individual and the country levels. By rotating one set of items towards the other, we show that these value dimensions have more in common than previously reported. The ranking of countries (N = 47) based on Schwartz's Embeddedness-Autonomy and the Survival-Self-Expression dimensions reached a maximum of similarity, r=.82, after rotating Inglehart's factor scores 27 degrees clockwise. The correlation between the other pair of dimensions (Schwartz's Hierarchy-Mastery-Egalitarianism-Harmony and Inglehart's Traditional-Secular-Rational values) was near zero before and after rotation. At the individual level (N = 46,444), positive correlations were found for Schwartz's Conservation-Openness dimension with both of Inglehart's dimensions (Survival-Self-Expression and Traditional-Secular-Rational values). The highest correlation with this Schwartz dimension was obtained at the Secular-Rational/Self-Expression diagonal, r=.24, after rotating the factor scores 45 degrees clockwise. We conclude that Schwartz's and Inglehart's originally proposed two-dimensional value structures share one dimension at the country level and some commonality at the individual level, whereas the respective other pair of dimensions seem to be more or less unrelated
Dynamic Time Warping and Geometric Edit Distance: Breaking the Quadratic Barrier
No full textDynamic Time Warping (DTW) and Geometric Edit Distance (GED) are basic similarity measures between curves or general temporal sequences (e.g., time series) that are represented as sequences of points in some metric space (X, dist). The DTW and GED measures are massively used in various fields of computer science and computational biology, consequently, the tasks of computing these measures are among the core problems in P. Despite extensive efforts to find more efficient algorithms, the best-known algorithms for computing the DTW or GED between two sequences of points in X = R^d are long-standing dynamic programming algorithms that require quadratic runtime, even for the one-dimensional case d = 1, which is perhaps one of the most used in practice.
In this paper, we break the nearly 50 years old quadratic time bound for computing DTW or GED between two sequences of n points in R, by presenting deterministic algorithms that run in O( n^2 log log log n / log log n ) time. Our algorithms can be extended to work also for higher dimensional spaces R^d, for any constant d, when the underlying distance-metric dist is polyhedral (e.g., L_1, L_infty)
On the Complexity of the k-Level in Arrangements of Pseudoplanes
No full textA classical open problem in combinatorial geometry is to obtain tight asymptotic bounds on the maximum number of k-level vertices in an arrangement of n hyperplanes in R^d (vertices with exactly k of the hyperplanes passing below them). This is essentially a dual version of the k-set problem, which, in a primal setting, seeks bounds for the maximum number of k-sets determined by n points in R^d, where a k-set is a subset of size k that can be separated from its complement by a hyperplane. The k-set problem is still wide open even in the plane. In three dimensions, the best known upper and lower bounds are, respectively, O(nk^{3/2}) [M. Sharir et al., 2001] and nk * 2^{Omega(sqrt{log k})} [G. Tóth, 2000].
In its dual version, the problem can be generalized by replacing hyperplanes by other families of surfaces (or curves in the planes). Reasonably sharp bounds have been obtained for curves in the plane [M. Sharir and J. Zahl, 2017; H. Tamaki and T. Tokuyama, 2003], but the known upper bounds are rather weak for more general surfaces, already in three dimensions, except for the case of triangles [P. K. Agarwal et al., 1998]. The best known general bound, due to Chan [T. M. Chan, 2012] is O(n^{2.997}), for families of surfaces that satisfy certain (fairly weak) properties.
In this paper we consider the case of pseudoplanes in R^3 (defined in detail in the introduction), and establish the upper bound O(nk^{5/3}) for the number of k-level vertices in an arrangement of n pseudoplanes. The bound is obtained by establishing suitable (and nontrivial) extensions of dual versions of classical tools that have been used in studying the primal k-set problem, such as the Lovász Lemma and the Crossing Lemma
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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