University of Luxembourg Open Access Publications and Communications
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See detailGradient Estimates on Dirichlet and Neumann Eigenfunctions
Arnaudon, Marc; Thalmaier, Anton UL; Wang, Feng-Yu

in International Mathematics Research Notices (in press)

By methods of stochastic analysis on Riemannian manifolds, we derive explicit two-sided gradient estimates for Dirichlet eigenfunctions on a d-dimensional compact Riemannian manifold D with boundary ... [more ▼]

By methods of stochastic analysis on Riemannian manifolds, we derive explicit two-sided gradient estimates for Dirichlet eigenfunctions on a d-dimensional compact Riemannian manifold D with boundary. Corresponding two-sided gradient estimates for Neumann eigenfunctions are derived in the second part of the paper. [less ▲]

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See detailAn Empirical Study on the Potential Usefulness of Domain Models for Completeness Checking of Requirements
Arora, Chetan UL; Sabetzadeh, Mehrdad UL; Briand, Lionel UL

in Empirical Software Engineering (in press)

[Context] Domain modeling is a common strategy for mitigating incompleteness in requirements. While the benefits of domain models for checking the completeness of requirements are anecdotally known, these ... [more ▼]

[Context] Domain modeling is a common strategy for mitigating incompleteness in requirements. While the benefits of domain models for checking the completeness of requirements are anecdotally known, these benefits have never been evaluated systematically. [Objective] We empirically examine the potential usefulness of domain models for detecting incompleteness in natural-language requirements. We focus on requirements written as “shall”- style statements and domain models captured using UML class diagrams. [Methods] Through a randomized simulation process, we analyze the sensitivity of domain models to omissions in requirements. Sensitivity is a measure of whether a domain model contains information that can lead to the discovery of requirements omissions. Our empirical research method is case study research in an industrial setting. [Results and Conclusions] We have experts construct domain models in three distinct industry domains. We then report on how sensitive the resulting models are to simulated omissions in requirements. We observe that domain models exhibit near-linear sensitivity to both unspecified (i.e., missing) and under-specified requirements (i.e., requirements whose details are incomplete). The level of sensitivity is more than four times higher for unspecified requirements than under-specified ones. These results provide empirical evidence that domain models provide useful cues for checking the completeness of natural-language requirements. Further studies remain necessary to ascertain whether analysts are able to effectively exploit these cues for incompleteness detection. [less ▲]

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See detailMaintenance location routing for rolling stock under line and fleet planning uncertainty
Arts, Joachim UL; Tönissen, Denise; Shen, Zuo-Jun

in Transportation Science (in press)

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See detailMinimum Wages and the Gender Gap in Pay: New Evidence from the United Kingdom and Ireland
Bargain, Olivier; Doorley, Karina; Van Kerm, Philippe UL

in Review of Income and Wealth (in press)

Women are disproportionately in low‐paid work compared to men so, in the absence of rationing effects on their employment, they should benefit the most from minimum wage policies. This study examines the ... [more ▼]

Women are disproportionately in low‐paid work compared to men so, in the absence of rationing effects on their employment, they should benefit the most from minimum wage policies. This study examines the change in the gender wage gap around the introduction of minimum wages in Ireland and the United Kingdom (U.K.). Using survey data for the two countries, we develop a decomposition of the change in the gender differences in wage distributions around the date of introduction of minimum wages. We separate out “price” effects attributed to minimum wages from “employment composition” effects. A significant reduction of the gender gap at low wages is observed after the introduction of the minimum wage in Ireland, while there is hardly any change in the U.K. Counterfactual simulations show that the difference between countries may be attributed to gender differences in non‐compliance with the minimum wage legislation in the U.K. [less ▲]

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See detailAn Agile Approach to Validate a Formal Representation of the GDPR
Bartolini, Cesare UL; Lenzini, Gabriele UL; Santos, Cristiana

in New Frontiers in Artificial Intelligence (in press)

Modelling in a knowledge base of logic formulæ the articles of the GDPR enables a semi-automatic reasoning of the Regulation. To be legally substantiated, it requires that the formulæ express validly the ... [more ▼]

Modelling in a knowledge base of logic formulæ the articles of the GDPR enables a semi-automatic reasoning of the Regulation. To be legally substantiated, it requires that the formulæ express validly the legal meaning of the Regulation's articles. But legal experts are usually not familiar with logic, and this calls for an interdisciplinary validation methodology that bridges the communication gap between formal modelers and legal evaluators. We devise such a validation methodology and exemplify it over a knowledge base of articles of the GDPR translated into Reified I/O (RIO) logic and encoded in LegalRuleML. A pivotal element of the methodology is a human-readable intermediate representation of the logic formulæ that preserves the formulæ's meaning, while rendering it in a readable way to non-experts. After being applied over a use case, we prove that it is possible to retrieve feedback from legal experts about the formal representation of Art. 5.1a and Art. 7.1. What emerges is an agile process to build logic knowledge bases of legal texts, and to support their public trust, which we intend to use for a logic model of the GDPR, called DAPRECO knowledge base. [less ▲]

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See detailStructural changes in the labor market and the rise of early retirement in France and Germany
Batyra, Anna; de la Croix, David; Pierrard, Olivier et al

in German Economic Review (in press)

The rise of early retirement in Europe is typically attributed to the European system of taxes and transfers. A model with an imperfectly competitive labor market allows us to consider also the effects of ... [more ▼]

The rise of early retirement in Europe is typically attributed to the European system of taxes and transfers. A model with an imperfectly competitive labor market allows us to consider also the effects of bargaining power and of matching efficiency on pre-retirement. We find that lower bargaining power of workers and declining matching efficiency have been important determinants of early retirement in France and Germany. These structural changes, combined with early-retirement transfers and population aging, are also consistent with the employment and unemployment rates, labor share and seniority premia. [less ▲]

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See detailThe Latent Topic Block Model for the Co-Clustering of Textual Interaction Data
Berge, Laurent UL; Bouveyron, Charles; Corneli, Marco et al

in Computational Statistics and Data Analysis (in press)

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See detailUnintended triadic closure in social networks: The strategic formation of research collaborations between French inventors.
Berge, Laurent UL; Carayol, Nicolas; Cassi, Lorenzo et al

in Journal of Economic Behavior and Organization (in press)

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See detailHow do inventor networks affect urban invention?
Berge, Laurent UL; Carayol, Nicolas; Roux, Pascale

in Regional Science & Urban Economics (in press)

Social networks are expected to matter for invention in cities, but empirical evidence is still puzzling. In this paper, we provide new results on urban patenting covering more than twenty years of ... [more ▼]

Social networks are expected to matter for invention in cities, but empirical evidence is still puzzling. In this paper, we provide new results on urban patenting covering more than twenty years of European patents invented by nearly one hundred thousand inventors located in France. Elaborating on the recent economic literatures on peer effects and on games in social networks, we assume that the productivity of an inventor’s efforts is positively affected by the efforts of his or her partners and negatively by the number of these partners’ connections. In this framework, inventors’ equilibrium outcomes are proportional to the square of their network centrality, which encompasses, as special cases, several well-known forms of centrality (Degree, Katz-Bonacich, Page-Rank). Our empirical results show that urban inventors benefit from their collaboration network. Their production increases when they collaborate with more central agents and when they have more collaborations. Our estimations suggest that inventors’ productivity grows sublinearly with the efforts of direct partners, and that they incur no negative externality from them having many partners. Overall, we estimate that a one standard deviation increase in local inventors’ centrality raises future urban patenting by 13%. [less ▲]

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See detailThe mod 2 cohomology rings of congruence subgroups in the Bianchi groups
Berkove, Ethan; Lakeland, Grant; Rahm, Alexander UL

E-print/Working paper (in press)

We provide new tools for the calculation of the torsion in the cohomology of congruence subgroups in the Bianchi groups : An algorithm for finding particularly useful fundamental domains, and an analysis ... [more ▼]

We provide new tools for the calculation of the torsion in the cohomology of congruence subgroups in the Bianchi groups : An algorithm for finding particularly useful fundamental domains, and an analysis of the equivariant spectral sequence combined with torsion subcomplex reduction. [less ▲]

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See detailA Methodology for Handling Data Movements by Anticipation: Position Paper
Bleuse, Raphaël UL; Lucarelli, Giorgio; Trystram, Denis

in Euro-Par 2018 Workshops (in press)

The enhanced capabilities of large scale parallel and distributed platforms produce a continuously increasing amount of data which have to be stored, exchanged and used by various tasks allocated on ... [more ▼]

The enhanced capabilities of large scale parallel and distributed platforms produce a continuously increasing amount of data which have to be stored, exchanged and used by various tasks allocated on different nodes of the system. The management of such a huge communication demand is crucial for reaching the best possible performance of the system. Meanwhile, we have to deal with more interferences as the trend is to use a single all-purpose interconnection network whatever the interconnect (tree-based hierarchies or topology-based heterarchies). There are two different types of communications, namely, the flows induced by data exchanges during the computations, and the flows related to Input/Output operations. We propose in this paper a general model for interference-aware scheduling, where explicit communications are replaced by external topological constraints. Specifically, the interferences of both communication types are reduced by adding geometric constraints on the allocation of tasks into machines. The proposed constraints reduce implicitly the data movements by restricting the set of possible allocations for each task. This methodology has been proved to be efficient in a recent study for a restricted interconnection network (a line/ring of processors which is an intermediate between a tree and higher dimensions grids/torus). The obtained results illustrated well the difficulty of the problem even on simple topologies, but also provided a pragmatic greedy solution, which was assessed to be efficient by simulations. We are currently extending this solution for more complex topologies. This work is a position paper which describes the methodology, it does not focus on the solving part. [less ▲]

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See detailAlmost Commutative Q-algebras and Derived brackets
Bruce, Andrew UL

in Journal of Noncommutative Geometry (in press)

We introduce the notion of almost commutative Q-algebras and demonstrate how the derived bracket formalism of Kosmann-Schwarzbach generalises to this setting. In particular, we construct ‘almost ... [more ▼]

We introduce the notion of almost commutative Q-algebras and demonstrate how the derived bracket formalism of Kosmann-Schwarzbach generalises to this setting. In particular, we construct ‘almost commutative Lie algebroids’ following Vaintrob’s Q-manifold understanding of classical Lie algebroids. We show that the basic tenets of the theory of Lie algebroids carry over verbatim to the almost commutative world. [less ▲]

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See detailThe Farrell--Tate and Bredon homology for PSL_4(Z) via cell subdivisions
Bui, Anh Tuan; Rahm, Alexander UL; Wendt, Matthias

in Journal of Pure and Applied Algebra (in press)

We provide some new computations of Farrell–Tate and Bredon (co)homology for arithmetic groups. For calculations of Farrell–Tate or Bredon homology, one needs cell complexes where cell stabilizers fix ... [more ▼]

We provide some new computations of Farrell–Tate and Bredon (co)homology for arithmetic groups. For calculations of Farrell–Tate or Bredon homology, one needs cell complexes where cell stabilizers fix their cells pointwise. We provide two algorithms computing an efficient subdivision of a complex to achieve this rigidity property. Applying these algorithms to available cell complexes for PSL_4(Z) provides computations of Farrell–Tate cohomology for small primes as well as the Bredon homology for the classifying spaces of proper actions with coefficients in the complex representation ring. [less ▲]

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See detailRigor or rhetoric: Public philosopher and public in dialogue
Burks, Deven UL

in Perspectives: international postgraduate journal of philosophy (in press), 9

Brian Leiter (2016) throws down two gauntlets to philosophers engaged in dialogue with the broader public. If, with the first, public philosophers recognize that they cannot offer substantive answers but ... [more ▼]

Brian Leiter (2016) throws down two gauntlets to philosophers engaged in dialogue with the broader public. If, with the first, public philosophers recognize that they cannot offer substantive answers but only sophisticated method, they nevertheless fail to realize that said method does not resonate with the very public whom they purport to help. For, with the second, that method does not engage the emotivist and tribalist cast of contemporary public discourse: emotivist because a person’s moral and political beliefs are a function of emotional attitudes or affective responses for which she adduces reasons post hoc; tribalist because the person tracks not the inferential relation between beliefs but her similarity with interlocutors. In order to understand the full extent of this critique, it is necessary, first, to parse strands of public philosophy, distinct discursive sites, and pictures of philosophical practice and, then, to probe the critique’s empirical groundedness and intended scope. These elements in place, it is then possible to sketch public philosophy reconceived along Leiter’s lines as equal part rigor and rhetoric. That sketch may be somewhat filled out through two tactics employed in Jeffrey Stout’s (2004, 2010) work. These form part of a toolkit for philosophical dialogue whereby philosophers get a discursive grip on non-discursive factors underlying public discourse and push back on Leiter's dilemma. [less ▲]

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See detailA gradualist path toward sortition
Burks, Deven UL; Kies, Raphaël UL

in Gastil, John; Wright, Erik Olin (Eds.) Legislature by Lot: Transformative Designs for Deliberative Governance (in press)

Conventional wisdom holds that building democracy takes time. Deliberative democracy will likely prove no exception. To that end, this chapter will explore one possible path towards more deliberative ... [more ▼]

Conventional wisdom holds that building democracy takes time. Deliberative democracy will likely prove no exception. To that end, this chapter will explore one possible path towards more deliberative institutions and decision-making in the form of Gastil and Wright’s proposal for a Sortition Chamber. Our thesis is that deliberative innovations, notably a sortition chamber, require a gradualist approach to implementation. While other authors in this volume may take for granted that some form of sortition chamber will be institutionalized and focus instead on design questions, we probe the necessary conditions preceding institutionalization. To support this thesis, we shall make an argument comprising four main claims. 1.) Sortition is a promising deliberative innovation. 2.) A strong, unaccountable deliberative device like sortition may delegitimize citizen deliberation and future deliberative innovations, in particular a sortition chamber. 3.) A weaker deliberative device like citizens’ consultation is effective though often blocked by a lack of institutional footing. 4.) Citizens’ consultation, once proven to be effective and regular, opens one path towards enhanced deliberative innovations like the sortition chamber. Claim 1.) will not be developed here beyond the point that a sortition chamber’s “hybrid legitimacy” may allow it to overcome critiques addressed to one-shot, single-issue consultative or 1 empowered mini-publics which may lack institutional footing1. Such mini-publics face multiple challenges: significant social or political uptake, electoral accountability, capture by interests, political redundancy, representativeness, biases, frames2. If a sortition chamber prima facie meets or precludes these different critiques, it represents a striking contribution to democratic innovations beyond mini-publics. That said, we must work out claims 2.), 3.) and 4.) in individual sections below. While examples in 3.) and 4.) will mainly be drawn from the European Union, we maintain that this argument is broadly applicable at local, regional national and transnational levels. We argue that, if institutionalizing consultative mini-publics is desirable and feasible at the EU level, it will be all the more so at other levels throughout the decision-making process’ different stages. [less ▲]

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See detailA Polynomial Time Subsumption Algorithm for Nominal Safe $ELO_{\bot}$ under Rational Closure
Casini, Giovanni UL; Straccia, Umberto; Meyer, Thomas

in Information Sciences (in press)

Description Logics (DLs) under Rational Closure (RC) is a well-known framework for non-monotonic reasoning in DLs. In this paper, we address the concept subsumption decision problem under RC for nominal ... [more ▼]

Description Logics (DLs) under Rational Closure (RC) is a well-known framework for non-monotonic reasoning in DLs. In this paper, we address the concept subsumption decision problem under RC for nominal safe $ELO_{\bot}$, a notable and practically important DL representative of the OWL 2 profile OWL 2 EL. Our contribution here is to define a polynomial time subsumption procedure for nominal safe $ELO_{\bot}$ under RC that relies entirely on a series of classical, monotonic $EL_{\bot}$ subsumption tests. Therefore, any existing classical monotonic $EL_{\bot}$ reasoner can be used as a black box to implement our method. We then also adapt the method to one of the known extensions of RC for DLs, namely Defeasible Inheritance-based DLs without losing the computational tractability. [less ▲]

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See detaile3-service: an ontology for needs-driven real-world service bundling in a multi-supplier setting
De Kinderen, Sybren UL; de Leenheer, Pieter; Gordijn, Jaap et al

in Applied Ontology (in press)

Businesses increasingly offer their services electronically via the Web. Take for example an Internet Service Provider. An ISP offers a variety of services, including raw bandwidth, IP connectivity, and ... [more ▼]

Businesses increasingly offer their services electronically via the Web. Take for example an Internet Service Provider. An ISP offers a variety of services, including raw bandwidth, IP connectivity, and Domain Name resolution. Although in some cases a single service already satisfies a customer need, in many situations a customer need is so complex that a bundle of services is needed to satisfy the need, as with the ISP example. In principle, each service in a bundle can be provisioned by a different supplier. This paper proposes an ontology, e3service , that can be used to formally capture customer needs, services, and multisupplier service bundles of these. In addition, this paper contributes a process called PCM2 to reason with the ontology. First, a customer need is identified for which desired consequences are elicited. Then, the desired set of consequences is matched with consequences associated with services. The matching process results in a service bundle, satisfying the customer need, containing services that each can be provided by different suppliers. PCM2 is inspired by a family of formal reasoning methods called Propose-Critique-Modify (PCM). However, whereas PCM methods emphasize solution generation from a given set of requirements, our reasoning process treats the space of requirements as a first class citizen. Hence PCM2 : the requirements space and solution space are equally important. How the reasoning and matching process practically works, is illustrated by an industry strength case study in the healthcare domain. [less ▲]

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See detailBisymmetric and quasitrivial operations: characterizations and enumerations
Devillet, Jimmy UL

in Aequationes Mathematicae (in press)

We investigate the class of bisymmetric and quasitrivial binary operations on a given set and provide various characterizations of this class as well as the subclass of bisymmetric, quasitrivial, and ... [more ▼]

We investigate the class of bisymmetric and quasitrivial binary operations on a given set and provide various characterizations of this class as well as the subclass of bisymmetric, quasitrivial, and order-preserving binary operations. We also determine explicitly the sizes of these classes when the set is finite. [less ▲]

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See detailAssociative, idempotent, symmetric, and order-preserving operations on chains
Devillet, Jimmy UL; Teheux, Bruno UL

in Order: A Journal on the Theory of Ordered Sets and its Applications (in press)

We characterize the associative, idempotent, symmetric, and order-preserving operations on (finite) chains in terms of properties of (the Hasse diagram of) their associated semilattice order. In ... [more ▼]

We characterize the associative, idempotent, symmetric, and order-preserving operations on (finite) chains in terms of properties of (the Hasse diagram of) their associated semilattice order. In particular, we prove that the number of associative, idempotent, symmetric, and order-preserving operations on an n-element chain is the nth Catalan number. [less ▲]

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See detailA New Perspective on the Luxembourgish Genitive
Döhmer, Caroline UL

in Germanic Genitives (in press)

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