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See detailExplicit descriptions of bisymmetric Sugeno integrals
Couceiro, Miguel UL; Lehtonen, Erkko UL

in Hüllermeier, Eyke; Kruse, Rudolf; Hoffmann, Frank (Eds.) Computational Intelligence for Knowledge-Based Systems Design (2010)

We provide sufficient conditions for a Sugeno integral to be bisymmetric. We explicitly describe bisymmetric Sugeno integrals over chains.

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See detailExplicit expressions of dual loads for accurate error estimation and bounding in goal oriented adaptivity
Ródenas, Juan José; Nadal, Enrique; González-Estrada, Octavio Andrés et al

in Moitinho de Almeida, J P; Díez, P; Tiago, C (Eds.) et al Adaptive Modeling and Simulation. Proceedings of VI ADMOS 2013 (2013)

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See detailExplicit finite deformation analysis of isogeometric membranes
Chen, Lei; Nguyen-Thanh, Nhon; Nguyen-Xuan, Hung et al

in Computer Methods in Applied Mechanics & Engineering (2014)

NURBS-based isogeometric analysis was first extended to thin shell/membrane structures which allows for finite membrane stretching as well as large deflection and bending strain. The assumed non-linear ... [more ▼]

NURBS-based isogeometric analysis was first extended to thin shell/membrane structures which allows for finite membrane stretching as well as large deflection and bending strain. The assumed non-linear kinematics employs the Kirchhoff-Love shell theory to describe the mechanical behaviour of thin to ultrathin structures. The displacement fields are interpolated from the displacements of control points only, and no rotational degrees of freedom are used at control points. Due to the high order Ck (k ≥ 1) continuity of NURBS shape functions the Kirchhoff-Love theory can be seamlessly implemented. An explicit time integration scheme is used to compute the transient response of membrane structures to time-domain excitations, and a dynamic relaxation method is employed to obtain steady-state solutions. The versatility and good performance of the present formulation is demonstrated with the aid of a number of test cases, including a square membrane strip under static pressure, the inflation of a spherical shell under internal pressure, the inflation of a square airbag and the inflation of a rubber balloon. The mechanical contribution of the bending stiffness is also evaluated. [less ▲]

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See detailExplicit form of the time operator of a gaussian stationary process
Suchanecki, Zdzislaw UL

in International Journal of Theoretical Physics (2004), 43

We present the time operator theory in the framework of stationary stochastic processes. The main results of the paper is the derivation of the time operator acting on the Fock space associated with a ... [more ▼]

We present the time operator theory in the framework of stationary stochastic processes. The main results of the paper is the derivation of the time operator acting on the Fock space associated with a discrete time gaussian stationary process. [less ▲]

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See detailExplicit formulae for time-space Brownian chaos
Peccati, Giovanni UL

in Bernoulli (2003), 9(1), 25--48

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See detailExplicit Kummer theory for quadratic fields
Hörmann, Fritz; Perucca, Antonella UL; Sgobba, Pietro UL 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 ▲]

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See detailExplicit Kummer theory for the rational numbers
Perucca, Antonella UL; Sgobba, Pietro UL; Tronto, Sebastiano UL

in International Journal of Number Theory (2020)

Let G be a finitely generated multiplicative subgroup of Q* having rank r. The ratio between n^r and the Kummer degree [Q(\zeta_m,\sqrt[n]{G}) : Q(\zeta_m)], where n divides m, is bounded independently of ... [more ▼]

Let G be a finitely generated multiplicative subgroup of Q* having rank r. The ratio between n^r and the Kummer degree [Q(\zeta_m,\sqrt[n]{G}) : Q(\zeta_m)], where n divides m, is bounded independently of n and m. We prove that there exist integers m_0, n_0 such that the above ratio depends only on G, \gcd(m,m_0), and \gcd(n,n_0). Our results are very explicit and they yield an algorithm that provides formulas for all the above Kummer degrees (the formulas involve a finite case distinction). [less ▲]

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See detailAn explicit two step quantization of Poisson structures and Lie bialgebras
Merkulov, Sergei UL; Willwacher, Thomas

in Communications in Mathematical Physics (2018), 364(2), 505578

We develop a new approach to deformation quantizations of Lie bialgebras and Poisson structures which goes in two steps. In the first step one associates to any Poisson (resp. Lie bialgebra) structure a ... [more ▼]

We develop a new approach to deformation quantizations of Lie bialgebras and Poisson structures which goes in two steps. In the first step one associates to any Poisson (resp. Lie bialgebra) structure a so called quantizable Poisson (resp. Lie bialgebra) structure. We show explicit transcendental formulae for this correspondence. In the second step one deformation quantizes a quantizable Poisson (resp. Lie bialgebra) structure. We show again explicit transcendental formulae for this second step correspondence (as a byproduct we obtain configuration space models for biassociahedron and bipermutohedron). In the Poisson case the first step is the most non-trivial one and requires a choice of an associator while the second step quantization is essentially unique, it is independent of a choice of an associator and can be done by a trivial induction. We conjecture that similar statements hold true in the case of Lie bialgebras. The main new result is a surprisingly simple explicit universal formula (which uses only smooth differential forms) for universal quantizations of finite-dimensional Lie bialgebras. [less ▲]

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See detailL’exploitation charbonnière dans le Pays de Liège sous l'Ancien Régime
Leboutte, René UL

in Westermann, E. (Ed.) Vom Bergbau- zum Industrierevier (1995)

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See detailExploitation du CVE-2015-4843
Bartel, Alexandre UL

Article for general public (2018)

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See detailExploitation of a bipolar-valued outranking relation for the choice of k best alternatives
Meyer, Patrick UL; Bisdorff, Raymond UL

Scientific Conference (2007, February)

We present the problem of the selection of k best alternatives in the context of multiple criteria decision aid. We situate ourselves in the context of pairwise comparisons of alternatives and the ... [more ▼]

We present the problem of the selection of k best alternatives in the context of multiple criteria decision aid. We situate ourselves in the context of pairwise comparisons of alternatives and the underlying bipolar-valued outranking digraph. We present three formulations for the best k-choice problem and detail how to solve two of them directly on the outranking digraph. [less ▲]

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See detailExploiting behavioral process data from computer-based testing
Goldhammer, Frank; Greiff, Samuel UL

Scientific Conference (2014, July)

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See detailExploiting Context Information for Computer-based Annotation Systems
Wehling, Ulf; Hoff, Christian; Rothkugel, Steffen UL et al

in Proceedings of the International Technology, Education and Development Conference (INTED 2007) (2007)

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See detailExploiting linguistic resources for self-employment: Workplace practices and language use of Thai immigrant entrepreneurs in the German periphery
Serwe, Stefan Karl UL

Doctoral thesis (2015)

This thesis is about immigrants in self-employment in Germany. More specifically, it is about immigrants who make a culturally-endowed practice or knowledge economically available in their new home. These ... [more ▼]

This thesis is about immigrants in self-employment in Germany. More specifically, it is about immigrants who make a culturally-endowed practice or knowledge economically available in their new home. These immigrant business owners are generally referred to as ethnic entrepreneurs. Yet, according to research and widely-held public opinions in Germany, a problem that hampers the success of these businesses is the owner's lack of proficiency in the German language, which apparently impedes them from accessing institutional support and from offering their services to the majority population. However, the ways that language competence actually affects the entry of immigrants into self-employment and the execution of their daily work as business owners has received only insufficient attention, including from a sociolinguistic perspective. Hence, this thesis aspires to examine the pathways of immigrants into self-employment and how these pathways are shaped by the owners' language knowledge. Secondly, by analysing the workplace practices in close empirical detail, it aims to understand how the owners' language knowledge impacts the execution of their work and whether these practices constitute sites of language learning for the owners. Thirdly, it intends to document the challenges that the business owners face at their workplaces, in order to understand to what extent they are due to insufficient levels of language knowledge. In order to answer these research questions, this study focuses on three businesses owned and operated by first-generation female immigrants from Thailand in the federal state of Saarland in southwest Germany. Businesses by Thai immigrants are particularly interesting for the purposes of this investigation, because they have flourished in recent years and because they offer their services in markets that target the majority, primarily German-speaking population. The ventures are typical examples of ethnic small businesses created by Thai immigrants in Germany: Thai massage salons and food retails stores. The first is a large Thai massage salon run by Kanita, the second a small Thai massage salon managed by Patcharin, and the third business is a food retail store owned and operated by Wipa. The three owners (and their staff) differ in terms of their competence in German. Kanita has only minimal competence in German, Patcharin has partial competence, while Wipa has maximum competence in the language. The analysis of the pathways into self-employment of these three owners exhibits a number of similarities. In all three cases, their migration to Germany was triggered by marriage to a German national. Previously, they all had professional careers which were directly connected to their appropriation of English, a language that later enabled communication with their German husbands. While their move to Germany was generally motivated by prospects of a better future, they were unable to find work due to a lack of German proficiency. German was primarily learned informally. Informal learning was fostered by their prior experience of language learning, their individual engagement in the form of self-study and reflexivity, a deliberate exposure to German through media, and their engagement with native speakers in practices towards which that they had developed an affinity. Interestingly, these practices were either their previous professional practices or activities that they took up after migration and later on developed into their own businesses. Realising the demand for their services in the open market and among the majority population kindled Kanita's, Patcharin's and Wipa's flame to enter self-employment. They deliberately adapted their services to the requirements of their customers, but also in reaction to prejudices about their professions. The support of their husbands and other associates was also significant, as they handled tasks that were difficult to perform linguistically, as, for example, the registration of the businesses and the preparation of administrative paperwork. In sum, these findings suggest that an advanced standard level of German was no prerequisite for these owners to enter self-employment, but that the prospects of engaging in self-employed work acted as an incentive to improve their German language skills. A detailed analysis of the workplace practices at Kanita's Massage Salon shows that working with minimal competence in German is possible, but that its success depends on several factors. To complete their workplace actions, Kanita and her staff draw on both resources in their linguistic repertoires, Thai and German. In addition, all workplace actions are designed as routine actions with discursive routines that all staff members are able to master quickly. Their successful accomplishment also depends on the customers' familiarity with these actions. Therefore, formal inconsistencies in German do generally not impede the performance of work, but problems are primarily due to the staff's or the customer's inexperience with the routines. If problems occur, they tend to be solved in cooperation with colleagues or by drawing on the material resources available to the staff members. In comparison to Kanita, Patcharin and her staff have partial competence in German, which is instrumental for the performance of the key practices at their workplace. The analysis shows that their restricted competence in German is important for their work, as it provides the tools for Patcharin and her staff to perform discursive practices during the massage treatment, such as finding out about their clients' health problems, building rapport with clients, giving instructions or clarifications about the treatment, or providing assessments of their customers' health issues. Talk is an important part of the massage treatment at Patcharin's salon and it aids to construct the professional identity that Patcharin claims for herself, namely to provide a high-quality and personalised service to her customers. Thai is less relevant, but in interactions between Patcharin and her staff it serves to exchange information and coordinate work. Wipa has maximum competence in German and Thai, which allows her to manage her store and serve her customers independently and competently in line with her professional aspirations. The key practices at her store of explaining and ordering stock illustrate how Wipa relies on both the use of Thai and German to effectively perform these actions. Her maximum competence in German and in Thai permits her to make 'rational' choices about the suitability of her suppliers and to provide her customers with advice that is tuned to their linguistic and cultural background. The conclusions drawn from these findings are that an advanced competence in German in not a prerequisite for immigrant entrepreneurs to start their businesses. The owners attune their workplace actions to the level of competence in their linguistic repertoires and operate effectively. Moreover, self-employed work provides the owners with the necessary motivation and the need to appropriate German. On the other hand, the data suggest that a greater proficiency in German becomes important, if the immigrant entrepreneur wants to differentiate her business from direct competitors, as it allows them to move beyond the concrete performance of routine actions. [less ▲]

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See detailExploiting locality of interaction in factored Dec-POMDPs
Oliehoek, Frans A.; Spaan, Matthijs T. J.; Vlassis, Nikos UL et al

in Int. Joint Conf. on Autonomous Agents and Multi-Agent Systems (2008)

Decentralized partially observable Markov decision processes (Dec-POMDPs) constitute an expressive framework for multiagent planning under uncertainty, but solving them is provably intractable. We ... [more ▼]

Decentralized partially observable Markov decision processes (Dec-POMDPs) constitute an expressive framework for multiagent planning under uncertainty, but solving them is provably intractable. We demonstrate how their scalability can be improved by exploiting locality of interaction between agents in a factored representation. Factored Dec-POMDP representations have been proposed before, but only for Dec-POMDPs whose transition and observation models are fully independent. Such strong assumptions simplify the planning problem, but result in models with limited applicability. By contrast, we consider general factored Dec-POMDPs for which we analyze the model dependencies over space (locality of interaction) and time (horizon of the problem). We also present a formulation of decomposable value functions. Together, our results allow us to exploit the problem structure as well as heuristics in a single framework that is based on collaborative graphical Bayesian games (CGBGs). A preliminary experiment shows a speedup of two orders of magnitude. [less ▲]

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See detailExploiting Long-Term Channel Correlation in Limited Feddback SDMA through Channel Phase Codebook
Huang, Yongming; Yang, Luxi; Bengtsson, Mats et al

in IEEE Transactions on Signal Processing (2011), 59(3), 1217-1228

Improving channel information quality at the base station (BS) is crucial for the optimization of frequency division duplexed (FDD) multi-antenna multiuser downlink systems with limited feedback. To this ... [more ▼]

Improving channel information quality at the base station (BS) is crucial for the optimization of frequency division duplexed (FDD) multi-antenna multiuser downlink systems with limited feedback. To this end, this paper proposes to estimate a particular representation of channel state information (CSI) at the BS through channel norm feedback and a newly developed channel phase codebook, where the long-term channel correlation is efficiently exploited to improve performance. In particular, the channel representation is decomposed into a gain-related part and a phase-related part, with each of them estimated separately. More specifically, the gain-related part is estimated from the channel norm and channel correlation matrix, while the phase-related part is determined using a channel phase codebook, constructed with the generalized Lloyd algorithm. Using the estimated channel representation, joint optimization of multiuser precoding and opportunistic scheduling is performed to obtain an SDMA transmit scheme. Computer simulation results confirm the advantage of the proposed scheme over state of the art limited feedback SDMA schemes under correlated channel environment. [less ▲]

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See detailExploiting Long-Term Redundancies in Reconstructed Video
Stojanovic, Aleksandar UL; Ohm, Jens-Rainer

in IEEE Journal on Selected Topics in Signal Processing (2013)

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See detailExploiting Long-term Statistics in Spatially Correlated Multi-user MIMO Systems with Quantized Channel Norm Feedback
Björnson, Emil; Ottersten, Björn UL

in Proceedings IEEE International Conference on Acoustics, Speech, and Signal (ICASSP) (2008)

In wireless multiple antenna and multi-user systems, the spatial dimensions may be exploited to increase the performance by means of antenna gain, spatial diversity, and multi-user diversity. A limiting ... [more ▼]

In wireless multiple antenna and multi-user systems, the spatial dimensions may be exploited to increase the performance by means of antenna gain, spatial diversity, and multi-user diversity. A limiting factor in such systems is the channel information required by the transmitter to control the intra-cell interference. Herein, the properties of spatially correlated channels with longterm statistical information at the transmitter and fixed-rate feedback of the quantized Euclidean channel norm are analyzed using a spectral subspace decomposition framework. A spatial division multiple access scheme is proposed with interference suppression at the receiver and joint scheduling and zero-forcing beamforming at the transmitter. Closed-form expressions for first and second moments of the feedback conditional channel statistics are derived. It is shown that only a few bits of feedback are required to achieve reliable rate estimation and weighted sum-rate maximization. [less ▲]

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See detailExploiting orthogonality in DVB-S2X through time pre-compensation
Andrenacci, Stefano UL; Chatzinotas, Symeon UL; Vanelli-Coralli, Alessandro et al

in Proceedings of 2016 8th Advanced Satellite Multimedia Systems Conference and the 14th Signal Processing for Space Communications Workshop (2016)

The superframing option of the recent DVB-S2X standard specifies, for the so-called SF-Pilot fields, the use of the orthogonal set of Walsh-Hadamard (WH) sequences. In order to exploit this orthogonality ... [more ▼]

The superframing option of the recent DVB-S2X standard specifies, for the so-called SF-Pilot fields, the use of the orthogonal set of Walsh-Hadamard (WH) sequences. In order to exploit this orthogonality, waveforms coming from different beams to the k-th User Terminal (UT) should be quasi perfectly aligned in time. While in the downlink part of a terrestrial system this is quite straightforward, in satellite system, having a satellite as a relay, this is not the case, especially when large baudrates are considered in the transmission. A procedure to compensate for timing misalignment amongst waveforms is here presented and the advantages are quantified through numerical simulations.In particular, Channel State Information (CSI) estimation errors, which are fundamental for precoding techniques, are evaluated. While the focus of the work is on systems which enable precoding techniques, the procedure can be applied in each scenario which uses the superframing structure of DVB-S2X in an interference limited scenario. [less ▲]

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