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See detailAn Experimental Analysis of Optimal Renewable Resource Management:The Fishery
Neugebauer, Tibor UL; Hey, John D; Sadrieh, Abdolkarim

E-print/Working paper (2008)

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See detailAre Capital Controls in the Foreign Exchange Market Effective?
Wolff, Christian UL; Straetmans, Stefan T.M.; Versteeg, Roald J.

E-print/Working paper (2008)

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See detailLaw, corporate governance and financial system: Econometric analysis of French case
Guigou, Jean-Daniel UL; Boughanmi, Afef; Blazy, Régis UL et al

E-print/Working paper (2008)

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See detailOn maximal independent sets in circulant digraphs
Bisdorff, Raymond UL

E-print/Working paper (2007)

In this research note we introduce St-Nicolas graphs, i.e. circulant digraphs showing exactly n maximal independent sets, isomorph under the digraph’s automorphisms group. This class of digraphs represent ... [more ▼]

In this research note we introduce St-Nicolas graphs, i.e. circulant digraphs showing exactly n maximal independent sets, isomorph under the digraph’s automorphisms group. This class of digraphs represent a generalisation of Andrásfai graphs with interesting links to finite group theory. [less ▲]

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See detailFinancial versus Social Efficiency of Corporate Bankruptcy Law: the French Dilemma ?
Guigou, Jean-Daniel UL; BLAZY, Régis UL; CHOPARD, Bertrand et al

E-print/Working paper (2007)

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See detailRelative Performance Evaluation, Risk Aversion and Entry
Guigou, Jean-Daniel UL; Lovat, Bruno; Piaser, Gwenaël UL

E-print/Working paper (2007)

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See detailEvaluation des performances relatives, risque et entrée
Guigou, Jean-Daniel UL; Lovat, B.

E-print/Working paper (2006)

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See detailImpact de l’attrait des places bancaires sur les taux d’intérêt créditeurs : Un modèle de formation des taux créditeurs estimé sur données en panel de banques européennes
Bourgain, Arnaud UL; Pieretti, Patrice UL; Rouabah, Abdelaziz

E-print/Working paper (2001)

This article evaluates the impact of banking centers' attractiveness on deposit interest rates. Using balance-sheet data from a set of 135 banks, the authors test an intermediation model of deposit rate ... [more ▼]

This article evaluates the impact of banking centers' attractiveness on deposit interest rates. Using balance-sheet data from a set of 135 banks, the authors test an intermediation model of deposit rate determination. In particular, the investigation shows a significant impact of « confidentiality » on deposit rates, thus confirming the importance of qualitative variables favouring local differentiation and clustering of banking activities. [less ▲]

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See detailEffets de complémentarité externes et incidence sur la productivité : le cas de l'industrie manufacturière luxembourgeoise
Bourgain, Arnaud UL; Pieretti, Patrice UL

E-print/Working paper (2001)

This article seeks to measure knowledge spillovers between nearby industries. This represents one of types of externality identified in the studies of industry location. A spillover indicator is suggested ... [more ▼]

This article seeks to measure knowledge spillovers between nearby industries. This represents one of types of externality identified in the studies of industry location. A spillover indicator is suggested which can explain increasing returns at the aggregate level. It is shown that this indicator is positively related to industry diversity. As applied to data from Luxembourg’s manufacturing industry, this indicator suggests that labor productivity is increasing in industry diversity. [less ▲]

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See detailOn linear decompositions of L-valued simple graphs
Bisdorff, Raymond UL

E-print/Working paper (1996)

In this report we will present a linear decomposition of a given L- valued binary relation into a set of sub-relations of kernel-dimension one. We will apply this theoretical result to the design of a ... [more ▼]

In this report we will present a linear decomposition of a given L- valued binary relation into a set of sub-relations of kernel-dimension one. We will apply this theoretical result to the design of a faster algorithm for computing L-valued kernels on general L-valued simple graphs. [less ▲]

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See detailQuel est l'intérêt d'une approche multi-dimensionnelle du jugement de préférence ?
Bisdorff, Raymond UL

E-print/Working paper (1995)

We present, in terms of logic programming, an algorithm for constructing decision rules from an extensional representation of the solutions to a multiple attributes decision problem. The algorithm is ... [more ▼]

We present, in terms of logic programming, an algorithm for constructing decision rules from an extensional representation of the solutions to a multiple attributes decision problem. The algorithm is based on the decision tree obtained from a hierarchical decomposition of the decision attributes along their discriminatory power of the decision acts. We illustrate our methodological approach with an application to the cognitive categorization of the human colour vision. [less ▲]

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See detailThe Hardest Logic Puzzle Ever
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailA new one point quadrature rule over arbitrary star convex polygon/polyhedron
Natarajan, Sundararajan; Francis, Amrita; Atroshchenko, Elena et al

E-print/Working paper (n.d.)

The Linear Smoothing (LS) scheme \cite{francisa.ortiz-bernardin2017} ameliorates linear and quadratic approximations over convex polytopes by employing a three-point integration scheme. In this work, we ... [more ▼]

The Linear Smoothing (LS) scheme \cite{francisa.ortiz-bernardin2017} ameliorates linear and quadratic approximations over convex polytopes by employing a three-point integration scheme. In this work, we propose a linearly consistent one point integration scheme which possesses the properties of the LS scheme with three integration points but requires one third of the integration computational time. The essence of the proposed technique is to approximate the strain by the smoothed nodal derivatives that are determined by the discrete form of the divergence theorem. This is done by the Taylor's expansion of the weak form which facilitates the evaluation of the smoothed nodal derivatives acting as stabilization terms. The smoothed nodal derivatives are evaluated only at the centroid of each integration cell. These integration cells are the simplex subcells (triangle/tetrahedron in two and three dimensions) obtained by subdividing the polytope. The salient feature of the proposed technique is that it requires only $n$ integrations for an $n-$ sided polytope as opposed to $3n$ in~\cite{francisa.ortiz-bernardin2017} and $13n$ integration points in the conventional approach. The convergence properties, the accuracy, and the efficacy of the LS with one point integration scheme are discussed by solving few benchmark problems in elastostatics. [less ▲]

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See detailON THE (NON-)EQUIVALENCE OF INTEGRAL BINARY QUADRATIC FORMS AND THEIR NEGATIVE FORMS
Barthel, Jim Jean-Pierre UL; Müller, Volker UL

E-print/Working paper (n.d.)

Integral binary quadratic forms have been extensively studied in order to compute the class number of real and complex quadratic fields. Many studies restricted the equivalence class of quadratic forms or ... [more ▼]

Integral binary quadratic forms have been extensively studied in order to compute the class number of real and complex quadratic fields. Many studies restricted the equivalence class of quadratic forms or identified specific forms in order to compute the class number through enumeration of equivalence classes. One often used assumption is that a given form and its negative are equivalent or are synthetically identified. This document presents a concise Lagrangian approach to integral binary quadratic forms, outlines the equivalence classes in its broadest sense and uses it to develop a general condition when a given integral binary quadratic form and its negative are equivalent. Then, the existence of integral binary quadratic forms which are non-equivalent to their negatives is proven and an elementary algorithm to determine the (non-)equivalence of a given form and its negative is outlined. [less ▲]

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See detailLinear smoothed extended finite element method
Murugesan; Natarajan, Sundararajan; Gadyam, Palani et al

E-print/Working paper (n.d.)

The extended finite element method (XFEM) was introduced in 1999 to treat problems involving discontinuities with no or minimal remeshing through appropriate enrichment functions. This enables elements to ... [more ▼]

The extended finite element method (XFEM) was introduced in 1999 to treat problems involving discontinuities with no or minimal remeshing through appropriate enrichment functions. This enables elements to be split by a discontinuity, strong or weak and hence requires the integration of discontinuous functions or functions with discontinuous derivatives over elementary volumes. Moreover, in the case of open surfaces and singularities, special, usually non-polynomial functions must also be integrated.A variety of approaches have been proposed to facilitate these special types of numerical integration, which have been shown to have a large impact on the accuracy and convergence of the numerical solution. The smoothed extended finite element method (SmXFEM) [1], for example, makes numerical integration elegant and simple by transforming volume integrals into surface integrals. However, it was reported in [1, 2] that the strain smoothing is inaccurate when non-polynomial functions are in the basis. This is due to the constant smoothing function used over the smoothing domains which destroys the effect of the singularity. In this paper, we investigate the benefits of a recently developed Linear smoothing procedure [3] which provides better approximation to higher order polynomial fields in the basis. Some benchmark problems in the context of linear elastic fracture mechanics (LEFM) are solved to compare the standard XFEM, the constant-smoothed XFEM (Sm-XFEM) and the linear-smoothed XFEM (LSm-XFEM). We observe that the convergence rates of all three methods are the same. The stress intensity factors (SIFs) computed through the proposed LSm-XFEM are however more accurate than that obtained through Sm-XFEM. To conclude, compared to the conventional XFEM, the same order of accuracy is achieved at a relatively low computational effort. [less ▲]

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See detailKummer extensions of number fields (the case of rank 2)
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailSOS Sudoku
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailWeakening the tight coupling between geometry and simulation in isogeometric analysis: from sub- and super- geometric analysis to Geometry Independent Field approximaTion (GIFT)
Atroshchenko, Elena; Xu, Gang; Tomar, Satyendra UL et al

E-print/Working paper (n.d.)

This paper presents an approach to generalize the concept of isogeometric analysis (IGA) by allowing different spaces for parameterization of the computational domain and for approximation of the solution ... [more ▼]

This paper presents an approach to generalize the concept of isogeometric analysis (IGA) by allowing different spaces for parameterization of the computational domain and for approximation of the solution field. The method inherits the main advantage of isogeometric analysis, i.e. preserves the original, exact CAD geometry (for example, given by NURBS), but allows pairing it with an approximation space which is more suitable/flexible for analysis, for example, T-splines, LR-splines, (truncated) hierarchical B-splines, and PHT-splines. This generalization offers the advantage of adaptive local refinement without the need to re-parameterize the domain, and therefore without weakening the link with the CAD model. We demonstrate the use of the method with different choices of the geometry and field splines, and show that, despite the failure of the standard patch test, the optimum convergence rate is achieved for non-nested spaces. [less ▲]

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See detailLinear smoothed polygonal and polyhedral finite elements
Francis, Amrita; Ortiz-Bernardin, Alejandro; Bordas, Stéphane UL et al

E-print/Working paper (n.d.)

It was observed in [1, 2] that the strain smoothing technique over higher order elements and arbitrary polytopes yields less accurate solutions than other techniques such as the conventional polygonal ... [more ▼]

It was observed in [1, 2] that the strain smoothing technique over higher order elements and arbitrary polytopes yields less accurate solutions than other techniques such as the conventional polygonal finite element method. In this work, we propose a linear strain smoothing scheme that improves the accuracy of linear and quadratic approximations over convex polytopes. The main idea is to subdivide the polytope into simplicial subcells and use a linear smoothing function in each subcell to compute the strain. This new strain is then used in the computation of the stiffness matrix. The convergence properties and accuracy of the proposed scheme are discussed by solving few benchmark problems. Numerical results show that the proposed linear strain smoothing scheme makes the approximation based on polytopes to deliver improved accuracy and pass the patch test to machine precision. [less ▲]

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See detailBoy or Girl?
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailThe first-digit law
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailKummer theory for multiquadratic or quartic cyclic number fields
Perissinotto, Flavio UL; Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailCongruence theorems for convex polygons involving sides, angles, and diagonals
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailOn basis vectors of lattices
Barthel, Jim Jean-Pierre UL; Müller, Volker UL

E-print/Working paper (n.d.)

Integer lattices enjoy increasing interest among mathematicians and cryptographers. However, there are still many elementary open questions, like finding specific vectors or particular bases of a given ... [more ▼]

Integer lattices enjoy increasing interest among mathematicians and cryptographers. However, there are still many elementary open questions, like finding specific vectors or particular bases of a given lattice. Our study consists in exhibiting which integer vectors may be chosen as basis vectors of a chosen lattice. The compelling part of our development is that this condition is obtained through an unusual application of Dirichlet's Theorem on primes in arithmetic progressions and that it has a surprising consequence for vectors achieving the successive minima. [less ▲]

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See detailA conjecture on primes in arithmetic progressions and geometric intervals
Barthel, Jim Jean-Pierre UL; Müller, Volker UL

E-print/Working paper (n.d.)

We conjecture that any interval of the form [q^t ,q^(t+1) ], where q≥ 2 and t≥1 denote positive integers, contains at least one prime from each coprime congruence class. We prove this conjecture first ... [more ▼]

We conjecture that any interval of the form [q^t ,q^(t+1) ], where q≥ 2 and t≥1 denote positive integers, contains at least one prime from each coprime congruence class. We prove this conjecture first unconditionally for all 2≤q≤45000 and all t≥1 and second under ERH for almost all q≥2 and all t≥2. Furthermore, we outline heuristic arguments for the validity of the conjecture beyond the proven bounds and we compare it with related long-standing conjectures. Finally, we discuss some of its consequences. [less ▲]

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See detailExplicit Kummer generators for cyclotomic extensions
Hoermann, Fritz; Perucca, Antonella UL; Sgobba, Pietro UL et al

E-print/Working paper (n.d.)

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See detailNew Constructions of Verifiable Delay Functions
Barthel, Jim Jean-Pierre UL; Rosie, Razvan UL

E-print/Working paper (n.d.)

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See detailFour Riddles with Four Brothers
Perucca, Antonella UL

E-print/Working paper (n.d.)

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See detailArithmetic Billiards
Perucca, Antonella UL; Reguengo da Sousa, Joe; Tronto, Sebastiano UL

E-print/Working paper (n.d.)

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See detailThree-dimensional arithmetic billiards
Perucca, Antonella UL

E-print/Working paper (n.d.)

Detailed reference viewed: 74 (2 UL)
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See detailKummer theory for products of one-dimensional tori
Perucca, Antonella UL; Perissinotto, Flavio

E-print/Working paper (n.d.)

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See detailDivisibility conditions on the order of the reductions of algebraic numbers
Sgobba, Pietro UL

E-print/Working paper (n.d.)

Let K be a number field, and let G be a finitely generated subgroup of K*. Without relying on (GRH) we prove an asymptotic formula for the number of primes \p of K such that the order of (G mod \p) is ... [more ▼]

Let K be a number field, and let G be a finitely generated subgroup of K*. Without relying on (GRH) we prove an asymptotic formula for the number of primes \p of K such that the order of (G mod \p) is divisible by a fixed integer. We also provide a rational expression for the natural density of this set. Furthermore, we study the primes \p for which the order is k-free, and those for which the order has a prescribed \ell-adic valuation for finitely many primes \ell. An additional condition on the Frobenius conjugacy class of \p may be considered. In order to establish these results, we prove an unconditional version of the Chebotarev density theorem for Kummer extensions of number fields. [less ▲]

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See detailNot participating in education, employment or training (NEET): Hope to mitigate new social risks in the UK?
Murphy, Emily UL; Holmes, Craig; Mayhew, Ken

E-print/Working paper (n.d.)

Young people not participating in education, employment or training (NEET) are a key policy concern in Europe. We examine whether hope, as a form of life course agency, plays a protective role against the ... [more ▼]

Young people not participating in education, employment or training (NEET) are a key policy concern in Europe. We examine whether hope, as a form of life course agency, plays a protective role against the risk of being NEET in the context of the British welfare state. Hope is conceptualised as multidimensional: being a temporally embedded, agentic mentality comprised of one’s sense of adaptive decision-making in the present and pathways thinking towards the future. Longitudinal estimations based on the latest Understanding Society microdata (2009-2018) indicate a direct association between higher-hope modes, on average, and a lower likelihood of being NEET. Further, our study assesses whether hopeful agency is moderated by the experience of parental worklessness. Findings indicate that while hope is not more important for those who experienced disadvantages in upbringing, hopeful agency is shown to be equally important in the face of past and present NEET risks. For the UK, building young peoples’ adaptive, agentic mentality towards their future in education or employment over the long-term, may prove one cost-effective policy approach. [less ▲]

Detailed reference viewed: 171 (51 UL)