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Wie Städte entstanden vornehmlich im mittelalterlichen und frühneuzeitlichen Nordwesteuropa Pauly, Michel E-print/Working paper (2007) Detailed reference viewed: 63 (1 UL)Autoindustrie in der Großregion SaarLorLux 2007 - Produktion, Forschung, Ausbildung Schulz, Christian ; ; et al E-print/Working paper (2007) Die Automobilindustrie gilt in der Großregion als wichtiger Pfeiler des wirtschaftlichen Strukturwandels. Eine Vielzahl teils hoch spezialisierter Zulieferer und Dienstleister prägt heute die ... [more ▼] Die Automobilindustrie gilt in der Großregion als wichtiger Pfeiler des wirtschaftlichen Strukturwandels. Eine Vielzahl teils hoch spezialisierter Zulieferer und Dienstleister prägt heute die Unternehmenslandschaft und stellt einen Großteil der industriellen Arbeitsplätze. Die Karte zeigt alle Betriebe des Sektors ab 500 Beschäftigten im Jahr 2007. Aufgrund der durch die Allgemeine Wirtschaftskrise ab 2008 aufgetretenen tief greifenden Veränderungen der Branche wurde dieser Beitrag durch einen zweiten, ausführlicheren Beitrag zur Autoindustrie der Großregion 2011 (C.K. Hahn, GR-Atlas Vol. 27) ergänzt. [less ▲] Detailed reference viewed: 87 (8 UL)Gestes, pratiques, corporéité et polyfocalisation de l’action dans le travail de techniciennes de surface. de Saint-Georges, Ingrid E-print/Working paper (2007) Detailed reference viewed: 81 (0 UL)The financing of the European Union Maufort, Laurence E-print/Working paper (2007) The European Union is a unique and exceptional organisation in many respects. Its financial system, whose rules and structure are very different from those of national budgetary law, has changed a great ... [more ▼] The European Union is a unique and exceptional organisation in many respects. Its financial system, whose rules and structure are very different from those of national budgetary law, has changed a great deal and is still changing. The most significant changes include: — The unification of budgetary instruments. Initially, each Community had its own budget or budgets (administrative and operating). These have now been replaced by a single budget, the general budget of the European Union. — Progress towards financial autonomy. Following the example of the ECSC, which was financed by real ‘tax revenue’ from the time it was set up, the EEC and Euratom changed to a system of own resources on 1 January 1971. — Reform of the Community financial system. The financial perspective, a genuine multiannual financial framework and instrument of budgetary discipline, was introduced in 1988. It forms an integral part of an interinstitutional agreement between Parliament, the Council and the Commission. — The pursuit of an institutional balance between the Council, Parliament and the Commission in the exercise of budgetary power. Initially, budgetary power lay solely with the Council. Parliament and the Council subsequently became the two arms of budgetary authority. The Commission retains a right to propose legislation in that sphere. The development of the financial system of the European Union superstructure is testament to its extremely varied history encompassing five decades and six enlargements. [less ▲] Detailed reference viewed: 87 (7 UL)Mittelalterliche Hospitäler in der Großregion SaarLorLux (von 600 bis 1500) Pauly, Michel ; Pauly, Michel ; Caruso, Geoffrey et al E-print/Working paper (2007) Im Raum zwischen Rhein und Maas, Aachen und Basel gab es zwischen 600 und 1500 insgesamt, wenn auch nicht gleichzeitig 528 verschiedene Hospitäler, also Herbergen für Reisende und Pilger, Armenhospize ... [more ▼] Im Raum zwischen Rhein und Maas, Aachen und Basel gab es zwischen 600 und 1500 insgesamt, wenn auch nicht gleichzeitig 528 verschiedene Hospitäler, also Herbergen für Reisende und Pilger, Armenhospize, Krankenhäuser, Entbindungsanstalten, Waisenheime, Pflegeheime für alte Menschen, Seniorenheime für reiche Pfründner u. ä. Beitrag und Karte fassen die Ergebnisse der Habilitationsschrift des Autors über „Hospitäler zwischen Maas und Rhein im Mittelalter. Typologische, topographische, funktionale und spirituelle Aspekte“ zusammen. [less ▲] Detailed reference viewed: 53 (6 UL)Mobilités pendulaires et résidentielles dans et vers le bassin d'emploi du Luxembourg Fehlen, Fernand ; Pigeron-Piroth, Isabelle ; E-print/Working paper (2006) Detailed reference viewed: 125 (9 UL)Evaluation des performances relatives, risque et entrée Guigou, Jean-Daniel ; E-print/Working paper (2006) Detailed reference viewed: 26 (0 UL)Kultur als Mehrwert. Überlegungen zum methodologischen Potenzial kulturwissenschaftlicher Theoreme für die literaturwissenschaftliche Analyse. (Rezension über: Franziska Schößler: Literaturwissenschaft als Kulturwissenschaft. Eine Einführung. Tübingen, Basel 2006). Mein, Georg E-print/Working paper (2006) Detailed reference viewed: 44 (0 UL)Tax competition, location and horizontal foreign direct investment ; Picard, Pierre M. E-print/Working paper (2005) We develop a model of capital tax competition in which imperfectly competitive firms choose both the number of plants they operate and their location. When compared to models with single-plant firms, the ... [more ▼] We develop a model of capital tax competition in which imperfectly competitive firms choose both the number of plants they operate and their location. When compared to models with single-plant firms, the presence of multinationals reverses some standard results. First, instead of being subsidized, capital may actually be taxed in equilibrium, which shows that the presence of taxable ‘multinational rents’ relaxes tax competition. Second, even when firms are subsidized, their subsidyinclusive profits may be decreasing in subsidies, due to fiercer price competition by more multinationals. Third, multinationals may give rise to multiple equilibria in the tax game, one of which can be a ‘subsidy trap’ characterized by many multinationals, high subsidy levels, and low welfare. [less ▲] Detailed reference viewed: 102 (18 UL)Theories of Knowledge. Is a naturalised epistemology bound to leave unanswered some important epistemological questions? Graf, Lukas E-print/Working paper (2005) Detailed reference viewed: 333 (2 UL)Critic of Amy Gutmann - The Constructive Potential of Communitarian Values for Liberalism Graf, Lukas E-print/Working paper (2005) The view of Amy Gutmann is that communitarians have been unsuccessful in undermining liberalism. However, she thinks that their work presents a welcome challenge to it. In her opinion, the communitarian ... [more ▼] The view of Amy Gutmann is that communitarians have been unsuccessful in undermining liberalism. However, she thinks that their work presents a welcome challenge to it. In her opinion, the communitarian criticism, rather than giving good reason to abandon liberalism, is of use in an attempt to discover a liberalism that successfully combines communitarian with liberal values. This paper examines the extent to which Gutmann successfully shows that communitarian values, like kinship, affection, or a sense of common purpose, have the latent but unrealized capacity to serve to improve liberalism. [less ▲] Detailed reference viewed: 110 (1 UL)Regulation of the Market for Standard Software: Waving Goodbye to 'Efficiency'? Zetzsche, Dirk Andreas ; E-print/Working paper (2005) The market for standard software shows an inexorable tendency towards concentration. Whereas such a development might be considered efficient due to the market's nature as a natural monopoly, it could ... [more ▼] The market for standard software shows an inexorable tendency towards concentration. Whereas such a development might be considered efficient due to the market's nature as a natural monopoly, it could also require stronger regulation, similar to other concentrated industries. This paper analyzes to what extent the existing legal frameworks under U.S. and European intellectual property and antitrust law mitigate pro-concentration effects. It characterizes the standard software market as an industry in need of regulation and reconsiders the current efficiency-focused approach in favor of measures that strengthen competition as a source of rivalry. Rather than considering efficiency arguments as "all-or-nothing" justification for otherwise anti-competitive conduct, as under the Chicago School concept, the concept proposed in this paper considers the "efficiency" criterion to merely limit the remedies imposed by adjudicators. [less ▲] Detailed reference viewed: 93 (1 UL)Contracting out and labor demand elasticities ; Picard, Pierre M ; E-print/Working paper (2005) We examine the relationship between contracting out and the wage elasticity of labor demand in outsourcing plants. A simple theoretical model suggests that firms engaged in contracting out have lower wage ... [more ▼] We examine the relationship between contracting out and the wage elasticity of labor demand in outsourcing plants. A simple theoretical model suggests that firms engaged in contracting out have lower wage elasticities. Estimating plant level dynamic labor demand equations for Irish manufacturing we find evidence supportive of this. [less ▲] Detailed reference viewed: 25 (2 UL)Präventives Sozialraummanagement: Soziales Frühwarnsystem und städtebauliche Prävention im Wohnquartier Biewers, Sandra ; ; E-print/Working paper (2005) Detailed reference viewed: 26 (0 UL)SOLUTIONS Micro-scale modelling: method and initial results Caruso, Geoffrey E-print/Working paper (2005) Detailed reference viewed: 43 (0 UL)Explicit and Implicit System of Corporate Control – A Convergence Theory of Shareholder Rights Zetzsche, Dirk Andreas E-print/Working paper (2004) Part B. of the paper compares the basic concepts of shareholder control in Anglo-America and some states of Continental Europe. It introduces a new categorization between Implicit and Explicit Systems of ... [more ▼] Part B. of the paper compares the basic concepts of shareholder control in Anglo-America and some states of Continental Europe. It introduces a new categorization between Implicit and Explicit Systems of Corporate Control. The first category refers to statutes that are enacted and construed with the belief that market forces influence managers. Shareholder rights to be exercised in direct contact with the corporation are thought to be relatively weak. This system is established in the Anglo-American world. In contrast, direct shareholder influence through voting and (even minority) shareholder monitoring constitute the fundaments of the Explicit System that traditionally prevailed, for example, in France and Germany. This paper provides historical, statutory and new empirical evidence from some Continental jurisdictions, and in particular Germany. It concludes that in Germany, shareholder meetings are part of Corporate Governance, while the Anglo-American corporate world traditionally understood this term to include only inter-board relationships. Part C. analyses the questions of whether, how and why Corporate Governance systems converge. This study suggests that Corporate Governance systems are likely to develop in Convergence Cycles: If a legal regime provides a particularly efficient solution to a specific problem, this solution will eventually be adopted by other Corporate Governance systems with an inferior system in respect of such problem. These Convergence Cycles will finally overcome the forces against formal convergence. The proposition of Convergence Cycles draws on historical, as well as new statutory and empirical evidence, collected by the author. Part D., finally, analyses the likely impact of convergence on ownership structures. It is likely that the answer to the question of which ownership structure is efficient depends on the stage of the business cycle that the firm is at. Firms within the same stage are likely to become more and more similar with respect to their ownership structures, until they reach an equilibrium that is set at a specific point for a particular group of firms. Thus, this paper adds a dynamic perspective to the static views that presently prevail in the debate upon the convergence of ownership structures. [less ▲] Detailed reference viewed: 107 (2 UL)Special Education and the Risk of Becoming Less Educated in Germany and the US Powell, Justin J W E-print/Working paper (2004) Detailed reference viewed: 46 (2 UL)Competition over piratable goods ; Picard, Pierre M E-print/Working paper (2004) The effects of (private, small-scale) copying on the pricing behavior of producers of information goods are studied within a unified model of vertical differentiation. Although information goods are ... [more ▼] The effects of (private, small-scale) copying on the pricing behavior of producers of information goods are studied within a unified model of vertical differentiation. Although information goods are assumed to be perfectly horizon tally differentiated, demands are interdependent because the copying technology exhibits increasing returns to scale. We characterize the symmetric Nash equilibria of the pricing game played by n producers of information goods. We show thereby how the producers' attitudes towards piracy are interdependent and evolve with the relative attractiveness of copies. [less ▲] Detailed reference viewed: 58 (1 UL)Das wachsende Risiko, als “sonderpädagogisch förderbedürftig” klassifiziert zu werden Powell, Justin J W E-print/Working paper (2004) Warum sind die Bildungschancenvon Schülern im hoch spezialisierten deutschen Sonderschulwesen so viel niedriger alsdie in den sonderpädagogischen Förderklassen der amerikanischen Gesamtschulen? Detailed reference viewed: 66 (0 UL)The European Parliament and the Challenge of Internet Voting ; ; Kies, Raphaël E-print/Working paper (2003) Detailed reference viewed: 46 (0 UL)Marco-level analysis of food-supply chain dynamics and diversity: An overview for Germany ; ; Sprenger, Birte E-print/Working paper (2003) This document is analysing the development and the state-of-the-art of food-supply chains in Germany. Detailed reference viewed: 43 (5 UL)The credibility of expert advice for regulatory decision-making in the US and EU König, Ariane ; E-print/Working paper (2002) Detailed reference viewed: 48 (5 UL)Effets de complémentarité externes et incidence sur la productivité : le cas de l'industrie manufacturière luxembourgeoise Bourgain, Arnaud ; Pieretti, Patrice 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 ▲] Detailed reference viewed: 65 (0 UL)Daten und Fakten zu Migrantenjugendlichen an Sonderschulen in der Bundesrepublik Deutschland Powell, Justin J W ; E-print/Working paper (2001) Zwischen 1965 und 1994 hat sich die Zahl der nichtdeutschen Schüler/innen in der Bundesrepublik Deutschland verzwanzigfacht. Seit dem Jahr 1991 gehen mehr als eine Million Schüler/innen mit ... [more ▼] Zwischen 1965 und 1994 hat sich die Zahl der nichtdeutschen Schüler/innen in der Bundesrepublik Deutschland verzwanzigfacht. Seit dem Jahr 1991 gehen mehr als eine Million Schüler/innen mit ausländischem Pass in (west-)deutsche Schulen; d.h. circa jede/r zehnte Schüler/in hat eine nichtdeutsche Staatsangehörigkeit. Über diese zahlenmäßige Präsens hinaus bieten die Vergleiche zwischen deutschen und nichtdeutschen Schülern/innen allgemein und zwischen deutschen und nichtdeutschen Sonderschülern/innen eine Perspektive, welche die Herausforderungen des Bildungssystems der Bundesrepublik Deutschland in ihrer Institutionalisierung und Expansion darstellt. Gleichzeitig stellen „in der BRD (...) die Ausländerkinder eine Gruppe dar, der im Bildungswesen besondere Aufmerksamkeit gewidmet werden muß, wenn sie nicht schulisch erheblich benachteiligt werden soll“ (Arbeitsgruppe Bildungsbericht am MPIB, 1994: 364). Von 1970 bis 1979 stieg der Anteil nichtdeutscher Schüler/innen an den Sonderschulen im Vergleich zu den Schülern insgesamt kontinuierlich an (Trommer/Köhler 1981: 130). Dieser Trend setzte sich fort, so dass bis 1999 nahezu 15% aller Sonderschüler/innen nichtdeutscher Herkunft waren, obwohl Schüler/innen nichtdeutscher Herkunft nur 9,4% aller Schüler/innen in der Bundesrepublik ausmachten. Das bedeutet für 1999 eine Überrepräsentanz ausländischer Kinder und Jugendlicher an deutschen Sonderschulen von 1,56. Parallel dazu zeigen die folgenden Analysen eine hohe Varianz zwischen den Bundesländern in der Sonderschulzuweisung nichtdeutscher Schüler/innen sowie unter den europäischen Nationalitäten (im Schuljahr 1998/99: von 0,5% bis hin zu 13,6%). Zugleich gibt es historisch Verschiebungen in der Begründung des Förderbedarfs zwischen dem größten Förderschwerpunkt „Lernen“ (von 82% auf 54% zwischen 1970-98) und anderen Kategorien des Förderbedarfs, die an Bedeutung gewonnen haben. Regionale Unterschiede in der Verteilung von Migrantenjugendlichen unter den einzelnen Sonderschularten sind u.a. Ausdruck der Differenzen in der Bildungs- bzw. Schulpolitik der Länder. So existieren große Unterschiede in der Akzeptanz integrativer pädagogischer Ansätze und Konzepte, der Ausbildung der Lehrer/innen und in der historischen Entwicklung verschiedener Schulformen. Die Existenz von Hauptschulen und Sonderschulen als quasi „untere bzw. separate Bildungsgänge“ sowie die Veränderung ihrer Schülerschaft in Folge der Bildungsexpansion und eine allgemein höhere Bildungsbeteiligung resultieren unter anderem darin, dass zwei von zehn nichtdeutschen Schulentlassenen die Schule ohne Hauptschulabschluss verlassen und deren „Misserfolgsquote“ immer noch ca. 2,5-mal so hoch ist wie bei den deutschen Jugendlichen (Solga 2001). Um die ausgewiesenen Ergebnisse zu Jugendlichen mit Migrationshintergrund an deutschen Sonderschulen adäquat einordnen zu können, werden in diesem Arbeitspapier auch ausgewählte Daten und Fakten zur allgemeinen Bildungsbeteiligung von Jugendlichen ausländischer Herkunft dargestellt und es wird auf demographische Schlüsseldaten eingegangen. Insgesamt zeigen die im Folgenden dargestellten Zahlen deutlich, dass—wie es heute in der Politik und den Medien nun endlich reflektiert wird—Jugendliche nichtdeutscher Herkunft im deutschen Bildungssystem benachteiligt sind und man immer noch versucht, ihre „Lernbehinderung“—die zum Großteil auch auf eine gesellschaftliche „Lernblockierung“ zurückgeht—mittels Sonder- bzw. Förderschulen und damit mittels institutioneller Separierung statt Integration zu lösen. [less ▲] Detailed reference viewed: 120 (5 UL)Etat des lieux des formations et de la recherche en ethnobotanique du domaine européen Reckinger, Rachel E-print/Working paper (2001) Detailed reference viewed: 30 (0 UL)Impact 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 ; Pieretti, Patrice ; 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 ▲] Detailed reference viewed: 71 (0 UL)Hinweis auf das Projekt : Effizienz des Frühunterrichts: begleitende Forschung im Rahmen der Fremdsprachenreformen“, esquisse de l’orientation de la recherche conduite au sein du projet d’étude sur l’introduction de l’enseignement précoce du français dans les écoles primaires de la Sarre Ehrhart, Sabine ; E-print/Working paper (2001) Detailed reference viewed: 47 (2 UL)On perfect, amicable, and sociable chains Marichal, Jean-Luc E-print/Working paper (2000) Let $\bfx = (x_0,\ldots,x_{n-1})$ be an $n$-chain, i.e., an $n$-tuple of non-negative integers $< n$. Consider the operator $s: \bfx \mapsto\bfx' = (x'_0,\ldots,x'_{n-1})$, where $x'_j$ represents the ... [more ▼] Let $\bfx = (x_0,\ldots,x_{n-1})$ be an $n$-chain, i.e., an $n$-tuple of non-negative integers $< n$. Consider the operator $s: \bfx \mapsto\bfx' = (x'_0,\ldots,x'_{n-1})$, where $x'_j$ represents the number of $j$'s appearing among the components of $\bfx$. An $n$-chain $\bfx$ is said to be perfect if $s(\bfx) = \bfx$. For example, (2,1,2,0,0) is a perfect 5-chain. Analogously to the theory of perfect, amicable, and sociable numbers, one can define from the operator $s$ the concepts of amicable pair and sociable group of chains. In this paper we give an exhaustive list of all the perfect, amicable, and sociable chains. [less ▲] Detailed reference viewed: 38 (3 UL)Analyse de l’évolution de la productivité totale des facteurs dans l’industrie luxembourgeoise Bourgain, Arnaud ; Pieretti, Patrice E-print/Working paper (1999) Detailed reference viewed: 53 (0 UL)Review of a BBS target article Lexical Entries and Rules of Language: A Multidisciplinary Study of German Inflection by Harald Clahsen to appear in BBS (1999) 22 (6) Reuter, Robert E-print/Working paper (1999) Many authors (e.g., Chomsky 1995, Pinker 1984, and Marcus 1998) argue that the architecture of the language faculty contains two separate components: a (structured) lexicon and a computational component ... [more ▼] Many authors (e.g., Chomsky 1995, Pinker 1984, and Marcus 1998) argue that the architecture of the language faculty contains two separate components: a (structured) lexicon and a computational component. Clahsen presents in a current BBS target article (in press) new empirical evidences in favour of such a dual-mechanism model of language processing based on a multidisciplinary study of German inflection. In the following review, I will summarise and discuss the major points of Clahsen's paper. My focus will be on theoretical, methodological and empirical issues presented and discussed in the paper. An important issue will be the bearing of his empirical findings on the current debate in psycholinguistic modelling. I will as well speculate that at least a part of Clahsen's reasoning seems not to hold in the case of a language closely related to German, namely Luxembourgian. [less ▲] Detailed reference viewed: 170 (2 UL)On the function of consciousness:An adaptationist perspective Reuter, Robert E-print/Working paper (1999) Detailed reference viewed: 34 (1 UL)On linear decompositions of L-valued simple graphs Bisdorff, Raymond 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 ▲] Detailed reference viewed: 13 (0 UL)Quel est l'intérêt d'une approche multi-dimensionnelle du jugement de préférence ? Bisdorff, Raymond 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 ▲] Detailed reference viewed: 53 (2 UL)Le français langue seconde dans les écoles maternelles et primaires de la République de Vanuatu (Pacifique Sud), Bilan d’une année d’étude dans le cadre de la « bourse d‘excellence postdoctorale Aupelf-Uref » Ehrhart, Sabine E-print/Working paper (1995) Detailed reference viewed: 42 (2 UL)Quelques réflexions concernant la genèse du tayo en Nouvelle-Calédonie et discussion des éventuels apports venant de l’extérieur, notamment du créole réunionnais, Conférence donnée à l'Université de Münster, 1991 Ehrhart, Sabine E-print/Working paper (1994) Detailed reference viewed: 99 (0 UL)New Constructions of Verifiable Delay Functions Barthel, Jim Jean-Pierre ; ; Rosie, Razvan E-print/Working paper (n.d.) A Verifiable Delay Function (VDF) is a cryptographic protocol thought to provide a proof of elapsed time. At the core of such a protocol lies a sequential task whose evaluation cannot be accelerated, even ... [more ▼] A Verifiable Delay Function (VDF) is a cryptographic protocol thought to provide a proof of elapsed time. At the core of such a protocol lies a sequential task whose evaluation cannot be accelerated, even in the presence of massive parallel computational resources. We introduce a novel sequentiality assumption, put forth a scheme that achieves this sequentiality constraint by requiring its users to evaluate a function over (levelled) fully homomorphic ciphertexts and provide a heuristic security analysis. [less ▲] Detailed reference viewed: 96 (6 UL)A new one point quadrature rule over arbitrary star convex polygon/polyhedron ; ; 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 ▲] Detailed reference viewed: 58 (3 UL)Correspondences between WZNW models and CFTs with W-algebra symmetry Roenne, Peter Browne ; ; E-print/Working paper (n.d.) Detailed reference viewed: 105 (3 UL)Bayesian inference for the stochastic identification of elastoplastic material parameters: Introduction, misconceptions and insights Rappel, Hussein ; Beex, Lars ; Hale, Jack et al E-print/Working paper (n.d.) We discuss Bayesian inference (BI) for the probabilistic identification of material parameters. This contribution aims to shed light on the use of BI for the identification of elastoplastic material ... [more ▼] We discuss Bayesian inference (BI) for the probabilistic identification of material parameters. This contribution aims to shed light on the use of BI for the identification of elastoplastic material parameters. For this purpose a single spring is considered, for which the stress-strain curves are artificially created. Besides offering a didactic introduction to BI, this paper proposes an approach to incorporate statistical errors both in the measured stresses, and in the measured strains. It is assumed that the uncertainty is only due to measurement errors and the material is homogeneous. Furthermore, a number of possible misconceptions on BI are highlighted based on the purely elastic case. [less ▲] Detailed reference viewed: 347 (104 UL)South Africa’s incomplete transition towards socio-economic justice: A case study on inequality and populism Owiso, Owiso ; E-print/Working paper (n.d.) South Africa is currently one of the world’s most unequal countries, with massive income inequality, millions of people living in poverty without access to basic services and amenities, unemployment rates ... [more ▼] South Africa is currently one of the world’s most unequal countries, with massive income inequality, millions of people living in poverty without access to basic services and amenities, unemployment rates consistently above 20% and the top 10% of the population receiving two thirds of the total income. Government economic policies on poverty reduction in the decades since the advent of democracy in South Africa in 1994 have been unable to eradicate the extreme racialised inequality which was the basis of the 342 years of colonialism and apartheid which were characterised by systematic dispossession and socio-economic marginalisation of South Africa’s majority Black population and the systematic privileging of the minority White population. While this history is not the primary focus of this paper, it nonetheless provides useful context. The paper’s primary focus is on the more recent normative and legal challenges of post-1994 South Africa that have resulted in further entrenching socio-economic inequality and contributing to the rise of populism. In this paper we argue that the dire living conditions of a large proportion of the population and disillusionment with the State’s ability to deliver on its promises in this regard, along with the poor implementation of social and economic rights have led to the development of a populist culture in South African politics. [less ▲] Detailed reference viewed: 82 (14 UL)Explicit Kummer theory for quadratic fields ; Perucca, Antonella ; Sgobba, Pietro et al E-print/Working paper (n.d.) Let K be a quadratic number field. If \alpha \in K*, we describe an explicit procedure to compute all Kummer degrees [K(\zeta_m,\sqrt[n]{\alpha}):K(\zeta_m)] for n,m \geq 1, where \zeta_m denotes a ... [more ▼] Let K be a quadratic number field. If \alpha \in K*, we describe an explicit procedure to compute all Kummer degrees [K(\zeta_m,\sqrt[n]{\alpha}):K(\zeta_m)] for n,m \geq 1, where \zeta_m denotes a primitive m-th root of unity and n divides m. We can also replace \alpha by any finitely generated subgroup of K*. [less ▲] Detailed reference viewed: 120 (10 UL)The Hardest Logic Puzzle Ever Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 45 (0 UL)Controlling the Error on Target Motion through Real-time Mesh Adaptation: Applications to Deep Brain Stimulation Bui, Huu Phuoc ; Tomar, Satyendra ; et al E-print/Working paper (n.d.) We present an error-controlled mesh refinement procedure for needle insertion simulation and apply it to the simulation of electrode implantation for deep brain stimulation, including brain shift. Our ... [more ▼] We present an error-controlled mesh refinement procedure for needle insertion simulation and apply it to the simulation of electrode implantation for deep brain stimulation, including brain shift. Our approach enables to control the error in the computation of the displacement and stress fields around the needle tip and needle shaft by suitably refining the mesh, whilst maintaining a coarser mesh in other parts of the domain. We demonstrate through academic and practical examples that our approach increases the accuracy of the displacement and stress fields around the needle without increasing the computational expense. This enables real-time simulations. The proposed methodology has direct implications to increase the accuracy and control the computational expense of the simulation of percutaneous procedures such as biopsy, brachytherapy, regional anesthesia, or cryotherapy and can be essential to the development of robotic guidance. [less ▲] Detailed reference viewed: 397 (34 UL)Arithmetic Billiards Perucca, Antonella ; ; Tronto, Sebastiano E-print/Working paper (n.d.) Detailed reference viewed: 46 (2 UL)Kummer theory for products of one-dimensional tori Perucca, Antonella ; E-print/Working paper (n.d.) Detailed reference viewed: 56 (23 UL)Not participating in education, employment or training (NEET): Hope to mitigate new social risks in the UK? Murphy, Emily ; ; 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: 77 (5 UL)Kummer extensions of number fields (the case of rank 2) Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 58 (14 UL)Weakening the tight coupling between geometry and simulation in isogeometric analysis: from sub- and super- geometric analysis to Geometry Independent Field approximaTion (GIFT) ; ; Tomar, Satyendra 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 ▲] Detailed reference viewed: 261 (13 UL)Verification of the Quillen conjecture in the rank 2 imaginary quadratic case Rahm, Alexander ; E-print/Working paper (n.d.) We confirm a conjecture of Quillen in the case of the mod 2 cohomology of arithmetic groups SL_2(A[1/2]), where A is an imaginary quadratic ring of integers. To make explicit the free module structure on ... [more ▼] We confirm a conjecture of Quillen in the case of the mod 2 cohomology of arithmetic groups SL_2(A[1/2]), where A is an imaginary quadratic ring of integers. To make explicit the free module structure on the cohomology ring conjectured by Quillen, we compute the mod 2 cohomology of SL_2(Z[sqrt(−2)][1/2]) via the amalgamated decomposition of the latter group. [less ▲] Detailed reference viewed: 57 (1 UL)Effective Kummer Theory for Elliptic Curves ; Tronto, Sebastiano E-print/Working paper (n.d.) Let E be an elliptic curve defined over a number field K, let α ∈ E(K) be a point of infinite order, and let N −1 α be the set of N -division points of α in E(K). We prove strong effective and uniform ... [more ▼] Let E be an elliptic curve defined over a number field K, let α ∈ E(K) be a point of infinite order, and let N −1 α be the set of N -division points of α in E(K). We prove strong effective and uniform results for the degrees of the Kummer extensions [K(E[N ], N −1 α) : K(E[N ])]. When K = Q, and under a minimal (necessary) assumption on α, we show that the inequality [Q(E[N ], N −1 α) : Q(E[N ])] ≥ cN 2 holds with a constant c independent of both E and α. [less ▲] Detailed reference viewed: 35 (7 UL)On the discrete Fuglede and Pompeiu problem Kiss, Gergely ; ; et al E-print/Working paper (n.d.) Detailed reference viewed: 38 (0 UL)Four Riddles with Four Brothers Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 36 (1 UL)The first-digit law Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 48 (0 UL)Staircase numbers Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 43 (0 UL)The least common multiple of several numbers in terms of greatest common divisors Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 18 (0 UL)Sharing calculations to understand arithmetical algorithms and parallel computing Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 88 (0 UL)Linear smoothed polygonal and polyhedral finite elements ; ; Bordas, Stéphane 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 ▲] Detailed reference viewed: 445 (10 UL)Every number is the beginning of a power of $2$ Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 38 (2 UL)On basis vectors of lattices Barthel, Jim Jean-Pierre ; Müller, Volker 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 ▲] Detailed reference viewed: 16 (1 UL)A conjecture on primes in arithmetic progressions and geometric intervals Barthel, Jim Jean-Pierre ; Müller, Volker 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 ▲] Detailed reference viewed: 13 (2 UL)Linear smoothed extended finite element method ; ; 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 ▲] Detailed reference viewed: 116 (3 UL)Kummer theory for number fields via entanglement groups Perucca, Antonella ; Sgobba, Pietro ; Tronto, Sebastiano E-print/Working paper (n.d.) Let $K$ be a number field, and let $G$ be a finitely generated and torsion-free subgroup of $K^\times$. We are interested in computing the degree of the cyclotomic-Kummer extension $K(\sqrt[n]{G})$ over ... [more ▼] Let $K$ be a number field, and let $G$ be a finitely generated and torsion-free subgroup of $K^\times$. We are interested in computing the degree of the cyclotomic-Kummer extension $K(\sqrt[n]{G})$ over $K$, where $\sqrt[n]{G}$ consists of all $n$-th roots of the elements of $G$. We develop the theory of entanglements introduced by Lenstra, and apply it to compute the above degrees. [less ▲] Detailed reference viewed: 91 (4 UL)ON THE (NON-)EQUIVALENCE OF INTEGRAL BINARY QUADRATIC FORMS AND THEIR NEGATIVE FORMS Barthel, Jim Jean-Pierre ; Müller, Volker 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 ▲] Detailed reference viewed: 69 (3 UL) |
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