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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 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)

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See detailAnalysis of primary microRNA loci from nascent transcriptomes reveals regulatory domains governed by chromatin architecture
Bouvy-Liivrand, Maria; Hernandez de Sande, Ana; Pölönen, Petri et al

in Nucleic Acids Research (2017)

Changes in mature microRNA (miRNA) levels that occur downstream of signaling cascades play an important role during human development and disease. However, the regulation of primary microRNA (pri-miRNA ... [more ▼]

Changes in mature microRNA (miRNA) levels that occur downstream of signaling cascades play an important role during human development and disease. However, the regulation of primary microRNA (pri-miRNA) genes remains to be dissected in detail. To address this, we followed a data-driven approach and developed a transcript identification, validation and quantification pipeline for characterizing the regulatory domains of pri-miRNAs. Integration of 92 nascent transcriptomes and multilevel data from cells arising from ecto-, endo- and mesoderm lineages reveals cell type-specific expression patterns, allows fine-resolution mapping of transcription start sites (TSS) and identification of candidate regulatory regions. We show that inter- and intragenic pri-miRNA transcripts span vast genomic regions and active TSS locations differ across cell types, exemplified by the mir-29a∼29b-1, mir-100∼let-7a-2∼125b-1 and miR-221∼222 clusters. Considering the presence of multiple TSS as an important regulatory feature at miRNA loci, we developed a strategy to quantify differential TSS usage. We demonstrate that the TSS activities associate with cell type-specific super-enhancers, differential stimulus responsiveness and higher-order chromatin structure. These results pave the way for building detailed regulatory maps of miRNA loci. [less ▲]

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See detailA Global Vertical Land Movement Data Set from a Combination of Global Navigation Satellite System Solutions
Hunegnaw, Addisu UL; Teferle, Felix Norman UL; Abraha, Kibrom Ebuy UL et al

Poster (2017, July 13)

Coastal sea-level measurements by tide gauges provide the longest instrumental records of sea-levels with some stretching from the 19th century to present. The derived mean sea-level (MSL) records provide ... [more ▼]

Coastal sea-level measurements by tide gauges provide the longest instrumental records of sea-levels with some stretching from the 19th century to present. The derived mean sea-level (MSL) records provide sea-level relative to a nearby tide gauge benchmark (TGBM), which allows for the continuation of this record in time after, for example, equipment modifications. Any changes in the benchmark levels induced by vertical land movements (VLM) affect the MSL records and hence the computed sea-levels. In the past, MSL records affected by VLM were often excluded from further analyses or the VLM were modelled using numerical models of the glacial isostatic adjustment (GIA) process. Over the last two decades Global Navigation Satellite System (GNSS), in particular Global Positioning System (GPS), measurements at or close to tide gauges and the development of the associated processing strategies, have made it possible to obtain estimates of VLM in a geocentric reference system, such as the International Terrestrial Reference Frame release 2008 (ITRF2008) that approach the required accuracy for sea-level studies. Furthermore, the GPS-derived VLM estimates have been shown to improve estimates of sea-level change compared to those using the aforementioned GIA models as these models cannot predict local subsidence or uplift. The International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group has recently re-processed the global GNSS data set from its archive (1000+ stations for 1995-2014) to provide VLM estimates tuned for the sea-level community. To achieve this, five TIGA Analysis Centers (TAC) contributed their reprocessed global GPS network solutions to the WG, all employing the latest bias models and processing strategies in accordance with the second re-processing compaign (repro2) of the IGS. These individual solutions were then combined by the TIGA Combination Center (TCC) to produce, for the first time, a TIGA combined solution (Release 0.99). This combined solution allows an evaluation of each individual TAC solution while also providing a means to gauge the quality and reliability of the combined solution, which is generally regarded as superior to the individual TAC solutions. Using time series analysis methods, estimates of VLM can then be derived from the daily position estimates, which are sub-sequentially employed to investigate coastal sea-levels. In this study, we show results from the evaluation of the relevant solutions, provide an evaluation of the TIGA VLM estimates and give examples of their impact on sea-level estimates for selected tide gauges from around the world. The TAC and TIGA combined solutions, as well as the derived VLM data sets are available from the IGS TIGA WG and will be accessible through SONEL (www.sonel.org) in the near future. [less ▲]

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See detailError-controlled computational fracture mechanics
Bordas, Stéphane UL

Scientific Conference (2017, July 12)

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See detailRisk-averse Stochastic Nonlinear Model Predictive Control for Real-time Safety-critical Systems
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in The 20th World Congress of the International Federation of Automatic Control, IFAC 2017 World Congress, Toulouse, France, 9-14 July 2017 (2017, July 11)

Stochastic nonlinear model predictive control has been developed to systematically find an optimal decision with the aim of performance improvement in dynamical systems that involve uncertainties. However ... [more ▼]

Stochastic nonlinear model predictive control has been developed to systematically find an optimal decision with the aim of performance improvement in dynamical systems that involve uncertainties. However, most of the current methods are risk-neutral for safety-critical systems and depend on computationally expensive algorithms. This paper investigates on the risk-averse optimal stochastic nonlinear control subject to real-time safety-critical systems. In order to achieve a computationally tractable design and integrate knowledge about the uncertainties, bounded trajectories generated to quantify the uncertainties. The proposed controller considers these scenarios in a risk-sensitive manner. A certainty equivalent nonlinear model predictive control based on minimum principle is reformulated to optimise nominal cost and expected value of future recourse actions. The capability of proposed method in terms of states regulations, constraints fulfilment, and real-time implementation is demonstrated for a semi-autonomous ecological advanced driver assistance system specified for battery electric vehicles. This system plans for a safe and energy-efficient cruising velocity profile autonomously. [less ▲]

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See detailTours de France
Scuto, Denis UL

Article for general public (2017)

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See detailWir stehen an einem Scheideweg
Steffgen, Georges UL

Article for general public (2017)

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See detailRisk, safety and assistive technology in the context of ageing-in-place
Lamotte, Mathilde UL; Ferring, Dieter UL; Tournier, Isabelle UL

Scientific Conference (2017, July 06)

When speaking about ageing in place, risk of accidents and subsequent injuries is an important part of individual worries, and risk avoidance or risk minimisation are main concerns of older people and ... [more ▼]

When speaking about ageing in place, risk of accidents and subsequent injuries is an important part of individual worries, and risk avoidance or risk minimisation are main concerns of older people and their caregivers. Findings show that older people are more at risk of unintended injuries than younger people (i.e. falls, foodborne diseases). Moreover, individual concerns and associated worries to avoid specific risks may even lead to the decision to move to an institution. In this context it is important to consider that being “as safe as possible” with respect to objective parameters does not necessarily indicate the subjective feeling of being safe. The feeling of safety and the objective degree of safety are not linearly related in a way that increasing one factor will increase the other and conversely. Furthermore, some factors that can contribute to objectively enhance safety may even lead to greater feeling of unsafety. Our review aims to investigate the relationship between objective and subjective safety in the context of ageing in place as well as the underlying mechanisms that help to explain the different links between objective and subjective safety. A further goal is offer a heuristic model presenting factors that may help to enhance older people’s consciousness of safety and thus quality of life. These include individual as well as social and macro-social factors. This paper focusses individual factors and will especially highlight the role of older people’s daily routines and their impact on technology acceptance. [less ▲]

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See detailIntroduction to Berezin-Toeplitz quantization
Schlichenmaier, Martin UL

Presentation (2017, July 05)

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