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See detailDie Trainierbarkeit von komplexem Problemlösen im Rahmen eines Trainings für Experimentieren.
Stebner, Ferdinand; Kunze, Thiemo UL; Kemper, Christoph UL et al

Scientific Conference (2017, September)

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See detailA Deep Learning Approach for Optimizing Content Delivering in Cache-Enabled HetNet
Lei, Lei UL; You, Lei; Dai, Gaoyang et al

in IEEE International Symposium on Wireless Communication Systems (ISWCS), Bologna, Aug. 2017 (2017, August 31)

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See detailEvolution systems of measures and semigroup properties on evolving manifolds
Cheng, Li Juan UL; Thalmaier, Anton UL

E-print/Working paper (2017)

An evolving Riemannian manifold $(M,g_t)_{t\in I}$ consists of a smooth $d$-dimensional manifold $M$, equipped with a geometric flow $g_t$ of complete Riemannian metrics, parametrized by $I=(-\infty,T ... [more ▼]

An evolving Riemannian manifold $(M,g_t)_{t\in I}$ consists of a smooth $d$-dimensional manifold $M$, equipped with a geometric flow $g_t$ of complete Riemannian metrics, parametrized by $I=(-\infty,T)$. Given an additional $C^{1,1}$ family of vector fields $(Z_t)_{t\in I}$ on $M$. We study the family of operators $L_t=\Delta_t +Z_t $ where $\Delta_t$ denotes the Laplacian with respect to the metric $g_t$. We first give sufficient conditions, in terms of space-time Lyapunov functions, for non-explosion of the diffusion generated by $L_t$, and for existence of evolution systems of probability measures associated to it. Coupling methods are used to establish uniqueness of the evolution systems under suitable curvature conditions. Adopting such a unique system of probability measures as reference measures, we characterize supercontractivity, hypercontractivity and ultraboundedness of the corresponding time-inhomogeneous semigroup. To this end, gradient estimates and a family of (super-)logarithmic Sobolev inequalities are established. [less ▲]

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See detailWhat do we need to say about a design method?
Gericke, Kilian UL; Eckert, Claudia; Stacey, Martin

in Proceedings of the 21st International Conference on Engineering Design (2017, August)

Method development is one of the raisons d’etre of engineering design research and method uptake by industry is perceived as an important success criterion. This paper argues that one of the problems with ... [more ▼]

Method development is one of the raisons d’etre of engineering design research and method uptake by industry is perceived as an important success criterion. This paper argues that one of the problems with methods is the lack of clarity about what is actually proposed to industry and the academic community when a new method is put forward, in terms of how detailed, strict, precise and rigorous the method is and what it can deliver. This paper puts the concept of method in the context of related concepts and proposes a multi-level model of the elements of a method to argue that a contribution on each of these levels can be of value and that the introduction of methods can fail on each of these levels. Implications thereof for industry and academia are discussed, concluding that a clear description of methods and their intended use is important for enabling proper validation of each of the method’s elements and for communicating methods to academia and industry. [less ▲]

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See detailDiscussant
Greiff, Samuel UL

Scientific Conference (2017, August)

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See detailAn engineering approach to mapping meanings in products and services
Waltersdorfer, Gregor UL; Gericke, Kilian UL; Desmet, Pieter M. A. et al

Scientific Conference (2017, August)

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See detailPolynésie et Mélanésie
Ehrhart, Sabine UL

in Reutner, Ursula (Ed.) Manuel des francophonies (2017)

Dans le présent article nous tenterons de dresser le portrait des situations d’utilisation du français dans l’océan Pacifique, dans une approche écologique, dynamique et holistique. Nous présenterons ... [more ▼]

Dans le présent article nous tenterons de dresser le portrait des situations d’utilisation du français dans l’océan Pacifique, dans une approche écologique, dynamique et holistique. Nous présenterons brièvement l’évolution historique et politique de chaque aire francophone, de son degré de francophonie et des liens qui existent entre le français et les autres langues parlées à chaque endroit, selon les domaines et fonctions d’utilisation. Certaines parties de cette vaste région se caractérisent par le tissage d’un réseau actif de relations interinsulaires. La Polynésie en est l’illustration type, alors qu’en revanche les espaces insulaires de la Mélanésie ont davantage tendance à être repliés sur eux-mêmes. [less ▲]

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See detailRandom Phase Center Motion Technique for Enhanced Angle-Doppler Discrimination Using MIMO Radars
Hammes, Christian UL; Shankar, Bhavani UL; Nijsure, Yogesh UL et al

Scientific Conference (2017, August)

A random Phase Center Motion (PCM) technique is presented in this paper, based on Frequency Modulated Continuous Wave (FMCW) radar, in order to suppress the angle- Doppler coupling in Time Division ... [more ▼]

A random Phase Center Motion (PCM) technique is presented in this paper, based on Frequency Modulated Continuous Wave (FMCW) radar, in order to suppress the angle- Doppler coupling in Time Division Multiplex (TDM) Multiple- Input-Multiple-Output (MIMO) radar when employing sparse array structures. The presented approach exploits an apparently moving transmit platform or PCM due to spatio-temporal transmit array modulation. In particular, the work considers a framework utilizing a random PCM trajectory. The statistical characterization of the random PCM trajectory is devised, such that the PCM and the target motion coupling is minimal, while the angular resolution is increased by enabling the virtual MIMO concept. In more details, this paper discusses sidelobe suppression approaches within the angle-Doppler Ambiguity Function (AF) by introducing a phase center probability density function within the array. This allows for enhanced discrimination of multiple targets. Simulation results demonstrate the suppression angle- Doppler coupling by more than 30 dB, even though spatiotemporal transmit array modulation is done across chirps which leads usually to strong angle-Doppler coupling. [less ▲]

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See detailA classification of polynomial functions satisfying the Jacobi identity over integral domains
Marichal, Jean-Luc UL; Mathonet, Pierre

in Aequationes Mathematicae (2017), 91(4), 601-618

The Jacobi identity is one of the properties that are used to define the concept of Lie algebra and in this context is closely related to associativity. In this paper we provide a complete description of ... [more ▼]

The Jacobi identity is one of the properties that are used to define the concept of Lie algebra and in this context is closely related to associativity. In this paper we provide a complete description of all bivariate polynomials that satisfy the Jacobi identity over infinite integral domains. Although this description depends on the characteristic of the domain, it turns out that all these polynomials are of degree at most one in each indeterminate. [less ▲]

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See detailThe role of international organisations in the New Math reform process
Nadimi Amiri, Shaghayegh UL

Scientific Conference (2017, August)

This paper studies a particular school reform that travelled over countries and continents. The target reform of this paper is the New Math reform, which started in the United States and travelled through ... [more ▼]

This paper studies a particular school reform that travelled over countries and continents. The target reform of this paper is the New Math reform, which started in the United States and travelled through many European countries. This article is part of my PhD project. I previously presented some of the results in different conferences, for instance: (Nadimi, 2015a, 2015b, 2016). The present paper studies the role of the international institutions in the adaptation of the reform in Luxembourg In 1958, the School Mathematics Study Group (SMSG) in the United States started a series of mathematics reform under the title “the New Math reform”. The aim of this reform plan was to promote the “problem solving” abilities in students (Phillips, 2014, pp. 16- 59). Many of mathematicians and math educators who became a member of the SMSG, had already started working on a new system of math education at the University of Chicago since 1955. However, the launch of Sputnik satellite by the USSR in 1957 gave the opportunity to trigger the New Math reform. The origin of the New Math reform was the ‘modern mathematics’ of the French Bourbaki group. A group of French mathematicians, since 1935, under the pseudonym Nicolas Bourbaki founded the “modern mathematics” by publishing the series of Elements of Mathematics (Bourbaki's_homepage). The reform came back to its land of origin through a conference organised by OEEC (Organisation for European Economic Co-operation) in the Royaumont abbey in Paris to foster the reform movement in Europe (OECD, 1961). The official title of the conference was “New thinking in mathematics education”, but it is known as the “Royaumont seminar”. OECD (the Organisation succeeding the OEEC) published the proceeding of the conference and organised other following conferences. The fact that OEEC/OECD hosts these conferences shows the politico-economic aspect of this reform. (Tröhler, 2015, p. 6) indicates that organisations like OEEC were created to link the national and the international, to create a global sphere, and to form an institutional or organisational channel to transfer desired ideas, policies, and curricula. The practical implementations of the New Math reform, in Europe, were discussed in two international organisations: ICMI (International Commission on Mathematical Instruction), founded in 1908, and CIEAEM (Commission Internationale pour l’Étude et l’Améloration de l’Enseignement des Mathématiques), established in 1950 (Vanpaemel, 2012). Furthermore, there were also local institutions, such as Centre Belge de Pédagogie de la Mathématique (CBPM). This centre had a close collaboration with Luxembourgian teachers and school stakeholders. This paper reviews the process of the New Math reform in Luxembourg by focusing on the interactions between the international institutions and the local school system. By telling the story of Luxembourg, the paper reveals a part of history related to the acts and efforts of the mentioned international organisations in the dissemination of the New Math reform idea in Europe. It shows how the national and international interactions could help the advancement of the reform and where the collaboration met challenges. The central question that shapes the paper is that up to what point the international cooperation of Luxembourgian stakeholders could be influential at the national level. This can be an example of how the acts and efforts of international organisations interact with the local interested parties in the development of an educational idea. [less ▲]

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See detailProblematic smartphone use and its relation with anxiety and depression: a survey in a large sample of undergraduates
Liu, Yueheng; Long, Jiang; Billieux, Joël UL et al

in Chinese Journal of Psychiatry (2017), 50(4), 270-275

[Objective] To investigate the differences of socio-demographics and smartphone use features among Chinese college students between problematic smartphone user (PSU) and non-PSU, and to clarify the link ... [more ▼]

[Objective] To investigate the differences of socio-demographics and smartphone use features among Chinese college students between problematic smartphone user (PSU) and non-PSU, and to clarify the link between PSU and psychopathological symptoms (anxiety and depression). [Methods] A total of 1 205 undergraduates from 35 classes of 8 universities or colleges, stratified with different school levels, were selected using the cluster random sampling strategy. The Problematic Cellular Phone Use Questionnaire (PCPUQ) was used to identify problematic use of smartphone use, and Zung Self-Rating Anxiety Scale (SAS) and Zung Self-Rating Depression Scale (SDS) were used to measure anxiety and depression symptoms. [Results] The prevalence of PSU among undergraduates was estimated to be 20.6% (207/1 006). There were significant differences between PSU and non-PSU on their major of either science category or humanities category (χ2=11.424 ,P<0.01), grade (χ2=5.868 ,P<0.05), monthly living expense supported by their family (χ2=12.713 ,P<0.01), daily time spent on their smartphones (χ2=20.052, P<0.01), frequency of changing the mobile phones (χ2=14.511 ,P<0.01) and monthly smartphone bill (χ2=13.107, P< 0.01). Furthermore, the self rated anxiety (34.8% (72/207) vs. 14.6% (117/799),χ2=43.704, P<0.01) and depression (36.2%(75/207) vs. 15.4%(123/799), χ2=45.159,P<0.01) were both found more elevated in PSU than non-PSU. [Conclusion] Some common sociodemographic variables and smartphone usage patterns were identified in undergraduates displaying PSU. Moreover, PSU is associated with more elevated anxiety and depression symptoms. Problematic smartphone use and its relation with anxiety and depression: a survey in a large sample of undergraduates (Article in Chinese). Available from: https://www.researchgate.net/publication/318762637_Problematic_smartphone_use_and_its_relation_with_anxiety_and_depression_a_survey_in_a_large_sample_of_undergraduates_Article_in_Chinese [accessed Aug 2, 2017]. [less ▲]

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See detailBelief Change in a Preferential Non-Monotonic Framework
Casini, Giovanni UL; Meyer, Thomas

in Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence (2017, August)

Belief change and non-monotonic reasoning are usually viewed as two sides of the same coin, with results showing that one can formally be defined in terms of the other. In this paper we show that we can ... [more ▼]

Belief change and non-monotonic reasoning are usually viewed as two sides of the same coin, with results showing that one can formally be defined in terms of the other. In this paper we show that we can also integrate the two formalisms by studying belief change within a (preferential) non-monotonic framework. This integration relies heavily on the identification of the monotonic core of a non-monotonic framework. We consider belief change operators in a non-monotonic propositional setting with a view towards preserving consistency. These results can also be applied to the preservation of coherence—an important notion within the field of logic-based ontologies. We show that the standard AGM approach to belief change can be adapted to a preferential non-monotonic framework, with the definition of expansion, contraction, and revision operators, and corresponding representation results. Surprisingly, preferential AGM belief change, as defined here, can be obtained in terms of classical AGM belief change. [less ▲]

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See detailFeedforward Chemical Neural Network: An In Silico Chemical System That Learns XOR
Blount, Drew; Banda, Peter UL; Teuscher, Christof et al

in Artificial Life (2017), 23(3), 295-317

Inspired by natural biochemicals that perform complex information processing within living cells, we design and simulate a chemically implemented feedforward neural network, which learns by a novel ... [more ▼]

Inspired by natural biochemicals that perform complex information processing within living cells, we design and simulate a chemically implemented feedforward neural network, which learns by a novel chemical-reaction-based analogue of backpropagation. Our network is implemented in a simulated chemical system, where individual neurons are separated from each other by semipermeable cell-like membranes. Our compartmentalized, modular design allows a variety of network topologies to be constructed from the same building blocks. This brings us towards general-purpose, adaptive learning in chemico: wet machine learning in an embodied dynamical system. [less ▲]

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See detailPanel participant
Greiff, Samuel UL

Scientific Conference (2017, August)