References of "Paper published in a journal"
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See detailTopologie culinaire au cinéma : le lieu commun du repas et ses déclinaison
Roelens, Nathalie UL

in Bibliothèque électronique Paris 8 (in press)

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See detailHigher Algebra over the Leibniz Operad
Poncin, Norbert UL

in Banach Center Publications (in press)

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See detailLe récit de voyage comme rupture de contrat
Roelens, Nathalie UL

in Acta Fabula : Revue des Parutions en Théorie Littéraire (in press)

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See detailHow Could an Intranet be Like a Friend to Me?: Why Standardized UX Scales Don't Always Fit
Lallemand, Carine UL; Koenig, Vincent UL

in Proceedings of the European Conference on Cognitive Ergonomics 2017 (2017, October)

"I hope that this survey is a joke because it made me laugh so much". This quote is just one example of many negative respondents' reactions gathered during a large-scale user experience (UX) study ... [more ▼]

"I hope that this survey is a joke because it made me laugh so much". This quote is just one example of many negative respondents' reactions gathered during a large-scale user experience (UX) study. Unfortunately, the survey was no joke, rather a well-constructed and validated standardized UX scale. This paper critically reflects on the use and relevance of standardized UX scales for the evaluation of UX in business contexts. We report on a real-world use case where the meCUE questionnaire has been used to assess employees' experience (N=263) with their organization's intranet. Strong users' reactions to the survey's items and statistical analyses both suggest that the scale is unsuitable for the evaluation of business-oriented systems. Drawing on the description of this inadequacy, we discuss the quality of academic UX tools, calling into question the relevance for practice of academic methods. [less ▲]

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See detailEstimating Urban Road Traffic States Using Mobile Network Signaling Data
Derrmann, Thierry UL; Frank, Raphaël UL; Viti, Francesco UL et al

in Abstract book of the 20th International Conference on Intelligent Transportation Systems (2017, October)

It is intuitive that there is a causal relationship between human mobility and signaling events in mobile phone networks. Among these events, not only the initiation of calls and data sessions can be used ... [more ▼]

It is intuitive that there is a causal relationship between human mobility and signaling events in mobile phone networks. Among these events, not only the initiation of calls and data sessions can be used in analyses, but also handovers between different locations that reflect mobility. In this work, we investigate if handovers can be used as a proxy metric for flows in the underlying road network, especially in urban environments. More precisely, we show that characteristic profiles of handovers within and between clusters of mobile network cells exist. We base these profiles on models from road traffic flow theory, and show that they can be used for traffic state estimation using floating-car data as ground truth. The presented model can be beneficial in areas with good mobile network coverage but low road traffic counting infrastructure, e.g. in developing countries, but also serve as an additional predictor for existing traffic state monitoring systems. [less ▲]

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See detailQuery-able Kafka: An agile data analytics pipeline for mobile wireless networks
Falk, Eric UL; Gurbani, Vijay K.; State, Radu UL

in Proceedings of the VLDB Endowment (2017, August), 10

Due to their promise of delivering real-time network insights, today's streaming analytics platforms are increasingly being used in the communications networks where the impact of the insights go beyond ... [more ▼]

Due to their promise of delivering real-time network insights, today's streaming analytics platforms are increasingly being used in the communications networks where the impact of the insights go beyond sentiment and trend analysis to include real-time detection of security attacks and prediction of network state (i.e., is the network transitioning towards an outage). Current streaming analytics platforms operate under the assumption that arriving traffic is to the order of kilobytes produced at very high frequencies. However, communications networks, especially the telecommunication networks, challenge this assumption because some of the arriving traffic in these networks is to the order of gigabytes, but produced at medium to low velocities. Furthermore, these large datasets may need to be ingested in their entirety to render network insights in real-time. Our interest is to subject today's streaming analytics platforms --- constructed from state-of-the art software components (Kafka, Spark, HDFS, ElasticSearch) --- to traffic densities observed in such communications networks. We find that filtering on such large datasets is best done in a common upstream point instead of being pushed to, and repeated, in downstream components. To demonstrate the advantages of such an approach, we modify Apache Kafka to perform limited \emph{native} data transformation and filtering, relieving the downstream Spark application from doing this. Our approach outperforms four prevalent analytics pipeline architectures with negligible overhead compared to standard Kafka. [less ▲]

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See detailOn the Unknown Input Functional Observer Design via Polytopic Lyapunov Function: Application to a Quadrotor Aerial Robots Landing
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in IFAC-PapersOnLine (2017, July)

In this paper, a constructive procedure to design functional unknown input observer for nonlinear continuous time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models systems ... [more ▼]

In this paper, a constructive procedure to design functional unknown input observer for nonlinear continuous time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models systems) is proposed. Applying the Lyapunov theory, Linear Matrix Inequalities (LMI)s conditions are deduced which are solved for feasibility to obtain observer design matrices. To reject the effect of unknown input, classical approach of decoupling the unknown input for the linear case is used. A comparative study between single and Polytopic Lyapunov function is made in order to prove the relaxation effect of the Multiple functions. A solver based solution is then proposed. It will be shown through applicative example (a Quadrotor Aerial Robots Landing) that even if the proposed LMIs solver based solution may look conservative, an adequate choice of the solver makes it suitable for the application of the proposed approach. [less ▲]

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See detailEnergy-Efficient Design for Edge-caching Wireless Networks: When is Coded-caching beneficial?
Vu, Thang Xuan UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Abstract book of IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) (2017, July)

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See detailEffectiveness of the Two-Step Dynamic Demand Estimation model on large networks
Cantelmo, Guido UL; Viti, Francesco UL; Derrmann, Thierry UL

in Proceedings of 2017 5th IEEE International Conference on Models and Technologies for Intelligent Transportation Systems (MT-ITS) (2017, June 28)

In this paper, the authors present a Two-Step approach that sequentially adjusts generation and distribution values of the (dynamic) OD matrix. While the proposed methodology already provided excellent ... [more ▼]

In this paper, the authors present a Two-Step approach that sequentially adjusts generation and distribution values of the (dynamic) OD matrix. While the proposed methodology already provided excellent results for updating demand flows on a motorway, the aim of this paper is to validate this conclusion on a real network: Luxembourg City. This network represents the typical middle-sized European city in terms of network dimension. Moreover, Luxembourg City has the typical structure of a metropolitan area, composed of a city centre, ring, and suburb areas. An innovative element of this paper is to use mobile network data to create a time-dependent profile of the generated demand inside and outside the ring. To support the claim that the model is ready for practical implementation, it is interfaced with PTV Visum, one of the most widely adopted software tools for traffic analysis. Results of these experiments provide a solid empirical ground in order to further develop this model and to understand if its assumptions hold for urban scenarios. [less ▲]

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See detailRare variant analysis of the PPMI dataset to uncover the complex genetic architecture of Parkinson’s disease
Bobbili, Dheeraj Reddy UL; May, Patrick UL; Krüger, Rejko UL

in Movement Disorders : Official Journal of the Movement Disorder Society (2017, June 02), 322(Supplement S2), 405

Objective: To unravel the genetic factors that play a role in PD we used the whole exome sequencing data available as a part of Parkinson Progression Markers Initiative (PPMI). Background: Parkinson’s ... [more ▼]

Objective: To unravel the genetic factors that play a role in PD we used the whole exome sequencing data available as a part of Parkinson Progression Markers Initiative (PPMI). Background: Parkinson’s disease (PD) is a complex disease. Besides variants in high-risk genes such as LRRK2 and PARK2, multiple genes associated to sporadic PD were discovered via genome-wide association studies. Yet, there is a large number of genetic factors that need to be deciphered. Methods: To unravel the genetic factors that play a role in PD we used the whole exome sequencing data available as a part of Parkinson Progression Markers Initiative (PPMI). The dataset comprised of 435 PD cases and 162 ethnically matched controls, respectively. We performed burden tests at single variant, gene and geneset levels on common and rare exonic and splice-variants. We also looked for severity of rare highly deleterious variants (CADD phred score>30) using the CADD score as well as singleton (variants seen in only one individual across cases and controls) rare variants. Additionally, we performed the functional enrichment analysis with the genes harboring rare highly deleterious variants (case uniq genes) that are only present in cases. Results: We observed an increased mutational burden of singleton variants in PD cases compared to the controls in nonsynonymous+LOF variants (empirical P-value 0.005) but not in the synonymous variants (empirical P-value 0.09). We observed a higher significant burden (P-value 0.028) as well as higher significant severity (empirical P-value 0.027) of rare, highly deleterious nonsynonymous variants, but not in the synonymous variants of the candidate genes (P-value 0.686, empirical P-value 0.556 for burden and severity respectively). The network analysis of genes having deleterious variants only present in cases (Case uniq) showed a significant increase in connectivity compared to random networks (P-value 0.0002). Pathway analysis of those genes showed a significant enrichment of pathways and biological process implicated in the nervous system functioning and the etiology of PD. Conclusions: Our study supports the complex disease notion of PD by highlighting the convoluted architecture of PD where case uniq genes including LRRK2 are implicated in several biological processes and pathways related to PD. The main finding of this study is to discover the complex genetics of PD at an exome wide level. [less ▲]

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See detailA contribution to Cyber-Security of Networked Control Systems: an Event-based Control Approach
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in Proceedings of 2017 3rd International Conference on Event-Based Control, Communication and Signal Processing (EBCCSP 2017) (2017, May)

In the present paper, a networked control system under both cyber and physical attacks is considered. An adapted formulation of the problem under physical attacks, data deception and false data injection ... [more ▼]

In the present paper, a networked control system under both cyber and physical attacks is considered. An adapted formulation of the problem under physical attacks, data deception and false data injection attacks, is used for controller synthesis. Based on the classical fault tolerant detection (FTD) tools, a residual generator for attack/fault detection based on observers is proposed. An event-triggered and Bilinear Matrix Inequality (BMI) implementation is proposed in order to achieve novel and better security strategy. The purpose in using this implementation would be to reduce (limit) the total number of transmissions to only instances when the networked control system (NCS) needs attention. It is important to note that the main contribution of this paper is to establish the adequate event-triggered and BMI-based methodology so that the particular structure of the mixed attacked/faulty structure can be re-formulated within the classical FTD paradigm. Experimental results are given to illustrate the developed approach efficiency on a pilot three-tank system. The plant model is presented and the proposed control design is applied to the system. [less ▲]

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See detailAutomatically Locating Malicious Packages in Piggybacked Android Apps
Li, Li UL; Li, Daoyuan UL; Bissyande, Tegawendé François D Assise UL et al

in Abstract book of the 4th IEEE/ACM International Conference on Mobile Software Engineering and Systems (MobileSoft 2017) (2017, May)

To devise efficient approaches and tools for detecting malicious packages in the Android ecosystem, researchers are increasingly required to have a deep understanding of malware. There is thus a need to ... [more ▼]

To devise efficient approaches and tools for detecting malicious packages in the Android ecosystem, researchers are increasingly required to have a deep understanding of malware. There is thus a need to provide a framework for dissecting malware and locating malicious program fragments within app code in order to build a comprehensive dataset of malicious samples. Towards addressing this need, we propose in this work a tool-based approach called HookRanker, which provides ranked lists of potentially malicious packages based on the way malware behaviour code is triggered. With experiments on a ground truth set of piggybacked apps, we are able to automatically locate the malicious packages from piggybacked Android apps with an accuracy of 83.6% in verifying the top five reported items. [less ▲]

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See detailUnknown Input Functional Observers Design for Polytopic Discrete Time Systems
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohemed

in Proceedings of 6th IEEE International Conference on Systems and Control (ICSC) 2017 (2017, May)

In this paper, a step by step algorithm is given to design functional unknown input observer for nonlinear discrete time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models ... [more ▼]

In this paper, a step by step algorithm is given to design functional unknown input observer for nonlinear discrete time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models systems). Applying the Lyapunov theory and the L2 attenuation, Linear Matrix Inequalities (LMI)s conditions are deduced which are solved for feasibility to obtain observer design matrices. To reject the effect of unknown input, classical approach of decoupling the unknown input for the linear case is used. A solver based solution is proposed. The novelty of the proposed approach consists in solving simultaneously both structural constraints and LMIs, which ensure a mean for the efficient design of the gains of the observers. To illustrate the proposed theoretical results, an application example of model reference tracking control applied to an electro-mechanical model of a motor with a time varying parameter is discussed. [less ▲]

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See detailOn the Diversity of Partial Relaying Cooperation with Relay Selection in Finite-SNR Regime
Vu, Thang Xuan UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE International Conference on Communications (2017, May)

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See detailSpectral-Efficient Model for Multiuser Massive MIMO: Exploiting User Velocity
Vu, Thang Xuan UL; Trinh, Anh Vu; Chatzinotas, Symeon UL et al

in IEEE international Conference on Communications (2017, May)

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See detailDetecting the "Big Red Spot" of age-period excess mortality in 25 countries: Age-period-cohort residual analysis
Chauvel, Louis UL; Leist, Anja UL; Smith, Herbert

in PAA Server (2017, April 28)

In times of wide availability of yearly mortality information of age and period groups all over the world, we lack in tools that detect and graph fine-grained deviations from mortality trends. We provide ... [more ▼]

In times of wide availability of yearly mortality information of age and period groups all over the world, we lack in tools that detect and graph fine-grained deviations from mortality trends. We provide a new age-period-cohort based methodology, combining information from age-period (AP) and APC-Detrended (APCD) analyses to detect all-cause mortality increases. Plotting the resulting AP coefficients and APCD residuals in equilateral Lexis diagrams, mortality patterns can easily be distinguished as age, period, or cohort trends and fluctuations. Additionally, we detect abnormalities as interactions of age and period (‘big red spots’). We then investigate the ‘red spots’ of mortality of young-adult cohorts in the early 1990s in Spain, other southern European countries and the U.S. to delineate their simultaneously occurring public health crises. Additional analyses with WHO mortality data show that mortality increases are mostly due to increased HIV/AIDS mortality. We discuss possible applications of the new method. [less ▲]

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See detailCoping with turn-taking:Investigating breakdowns in human-robot interaction from a Conversation Analysis (CA) perspective
Arend, Béatrice UL; Sunnen, Patrick UL

in Proceedings: The 8th International Conference on Society and Information Technologies (2017, March)

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See detailToward an in-depth understanding of binge-watching behavior: a qualitative approach with focus group
Flayelle, Maèva UL; Maurage, Pierre; Billieux, Joël

in Journal of behavioral addictions (2017, March), 6 (Suppl.1)

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See detailSimiDroid: Identifying and Explaining Similarities in Android Apps
Li, Li UL; Bissyande, Tegawendé François D Assise UL; Klein, Jacques UL

in Abstract book of the 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom) (2017)

App updates and repackaging are recurrent in the Android ecosystem, filling markets with similar apps that must be identified and analysed to accelerate user adoption, improve development efforts, and ... [more ▼]

App updates and repackaging are recurrent in the Android ecosystem, filling markets with similar apps that must be identified and analysed to accelerate user adoption, improve development efforts, and prevent malware spreading. Despite the existence of several approaches to improve the scalability of detecting repackaged/cloned apps, researchers and practitioners are eventually faced with the need for a comprehensive pairwise comparison to understand and validate the similarities among apps. This paper describes the design of SimiDroid, a framework for multi-level comparison of Android apps. SimiDroid is built with the aim to support the understanding of similarities/changes among app versions and among repackaged apps. In particular, we demonstrate the need and usefulness of such a framework based on different case studies implementing different analysing scenarios for revealing various insights on how repackaged apps are built. We further show that the similarity comparison plugins implemented in SimiDroid yield more accurate results than the state-of-the-art. [less ▲]

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See detailBoard Game Prototyping to Co-Design a Better Location-Based Digital Game
Jones, Catherine UL; Liapis; Lykourentzou, Ioanna et al

in Abstract book of the 2017 CHI Conference Extended Abstracts on Human Factors in Computing Systems - CHI EA '17 (2017)

In this case study we describe the iterative process of paper prototyping, using a board game, to co-design a location-based mobile application. The end goal of the application is to motivate reflection ... [more ▼]

In this case study we describe the iterative process of paper prototyping, using a board game, to co-design a location-based mobile application. The end goal of the application is to motivate reflection on historical topics about migration. The board game serves to capture the core concerns of this application by simulating movement through the city. Three play tests highlighted the users' interest and issues with the historical content, the way this content is represented, and the players' responses to the interactions and motivating mechanisms of the application. Results show that the board game helped capture important design preferences and problems, ensuring the improvement of our scenario. This feedback can help reduce development effort and implement a future technology prototype closer to the needs of our end users. [less ▲]

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See detailAn comprehensive and cost-efficient approach in assessing WWTP's degradation performance of xenobiotics
Köhler, Christian; Gallé, Tom; Bayerle, Michael et al

in Proceeding of 10th Micropol & Ecohazard Conference 2017 (2017)

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See detailDiskursivität und Einheit des Bewusstseins bei Kant
Heidemann, Dietmar UL

in Kant-Studien (2017)

Im ersten Abschnitt des Beitrags wird der Zusammenhang von Kantischer Begriffslehre und Theorie des transzendentalen Selbstbewusstseins transparent gemacht. Die Einheit des Bewusstseins, so wird die ... [more ▼]

Im ersten Abschnitt des Beitrags wird der Zusammenhang von Kantischer Begriffslehre und Theorie des transzendentalen Selbstbewusstseins transparent gemacht. Die Einheit des Bewusstseins, so wird die Rekonstruktion dieses Zusammenhanges ergeben, gründet in der Theorie des diskursiven Begriffs. Die dabei herausgearbeitete Konzeption der diskursiven Identität wird dann im zweiten Abschnitt anhand des dritten Paralogismus der ersten Auflage der Kritik der reinen Vernunft mit dem Begriff der personalen Identität kontrastiert, um zu zeigen, warum der auch hier bestehende konstitutive Zusammenhang zwischen kognitiver Einheit und Identität des Bewusstseins zu keiner spezifischen Erkenntnis hinsichtlich des Bewusstseins führt. Während die transzendentale Deduktion die Theorie nichtzeitlicher, logischer Einheit und diskursiver Identität der transzendentalen Apperzeption entfaltet, thematisiert der dritte Paralogismus das mentale Phänomen kontingenter, temporaler Einheit und damit personaler Identität. Über die prinzipiellen Bedeutungsunterschiede dieser beiden Konzeptionen von Einheit und Identität im Bereich des Mentalen ist Klarheit zu schaffen. Der Schlussteil widmet sich einigen naheliegenden Einwänden gegen den in diesem Beitrag entwickelten Interpretationsvorschlag. Insbesondere wird eine Kritik an der hier verteidigten Diskursivitätsthese diskutiert, derzufolge die Einheit des Bewusstseins in der Diskursivität des Verstandes bzw. Begriffs und nicht umgekehrt die Diskursivität des Verstandes bzw. des Begriffs in der Einheit des Bewusstseins gründet [less ▲]

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See detailIDENTIFICATION OF A RARE GENE VARIANT THAT IS ASSOCIATED WITH FAMILIAL ALZHEIMER DISEASE AND REGULATES APP EXPRESSION
Hartl, Daniela; May, Patrick UL; Gu, Wei UL et al

in Alzheimer's & Dementia : The Journal of the Alzheimer's Association (2017), 13(7, Supplement), 648

Background Genetic mutations leading to familial forms of Alzheimer disease (AD) have so far been reported for a few genes including APP, PSEN1 and PSEN2, UNC5C, PLD3, ABCA7, TTC3, and possibly ADAM10 ... [more ▼]

Background Genetic mutations leading to familial forms of Alzheimer disease (AD) have so far been reported for a few genes including APP, PSEN1 and PSEN2, UNC5C, PLD3, ABCA7, TTC3, and possibly ADAM10. With the advent of whole exome and whole genome sequencing approaches new genes and mutations are likely to be identified. Methods We analyzed the genetic cause of AD in a large multiplex family with an autosomal-dominant pattern of inheritance with LOAD. The family lacked pathogenic mutations of known AD genes. We performed whole-genome sequencing (WGS) in six family members (two affected and four unaffected) and prioritized rare, potential damaging, variants that segregated with disease. Variants were further characterized by subsequent molecular analyzes in human brain and cell culture models. Results We identified a single rare nonsynonymous variant co-segregating with AD. The mutation inhibits pro-protein cleavage and the formation of the active enzyme, thus leading to a loss-of-function of the gene. We further found a strong negative correlation between the identified gene and APP gene expression in human brain and in cells over-expressing the gene. The negative regulation of APP expression was only observed for the wt gene, but not for mutated forms, thus causing beside the loss of enzyme function a decoupling of both APPexpression and subsequent beta-amyloid formation. The identity of the gene will be presented on the conference. Conclusions This novel pathway strongly supports a causative association of the identified gene with the pathogenesis of AD. [less ▲]

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See detailCognitive inequalities in later life: Cross-country differences in the education-cognition gradient
Leist, Anja UL

in Innovation in Aging (Gerontological Society of America) (2017), 1(Suppl. 1), 16

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See detailLES-VOF SIMULATIONS OF A PURE WATER JET DEVELOPING INSIDE AN AWJC NOZZLE: PRELIMINARY OBSERVATIONS AND GUIDELINES
Pozzetti, Gabriele UL; Peters, Bernhard UL

in 2017 WJTA-IMCA Conference Proceedings (2017)

In this work, a numerical approach to predict the behavior of a pure water jet developing inside a nozzle for Abrasive Water Jet Cutting (AWJC) is investigated. In a standard AWJC configuration, the water ... [more ▼]

In this work, a numerical approach to predict the behavior of a pure water jet developing inside a nozzle for Abrasive Water Jet Cutting (AWJC) is investigated. In a standard AWJC configuration, the water jet carries the major energy content of the entire system, and is responsible for accelerating abrasive particles that will perform the cutting action of hard materials. Therefore an accurate simulation of a pure water jet can bring significant insight on the overall AWJC process. Capturing the behavior of a multiphase high-speed flow in a complex geometry is however particularly challenging. In this work, we adopt a combined approach based on the Volume of Fluid (VOF) and Large Eddy Simulation (LES) techniques in order to respectively capture the water/air interface and to model turbulent structures of the flow. The aim of this contribution is to investigate how the two techniques apply to the specific problem, and to offer general guidelines for practitioners willing to adopt them. Costs considerations will be then presented with particular reference to the usage of the OpenFOAM® environment. The reported results are meant to provide guidance for AWJ applications and future developments of AWJ nozzles. [less ▲]

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See detailTowards Integration on Colored Supermanifolds
Poncin, Norbert UL

in Banach Center Publications (2016, December), 110

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See detailOn the Insecurity of a Method for Providing Secure and Private Fine-Grained Access to Outsourced Data
Rial, Alfredo UL

in Abstract book of 2016 IEEE 8th International Conference on Cloud Computing Technology and Science (CloudCom) (2016, December)

The protection of sensitive data stored in the cloud is paramount. Among the techniques proposed to provide protection, attribute-based access control, which frequently uses ciphertext-policy attribute ... [more ▼]

The protection of sensitive data stored in the cloud is paramount. Among the techniques proposed to provide protection, attribute-based access control, which frequently uses ciphertext-policy attribute-based encryption (CPABE), has received a lot of attention in the last years. Recently, Jahan et al.~(IEEE 40th Conference on Local Computer Networks, 2015) propose a scheme based on CPABE where users have reading and writing access to the outsourced data. We analyze the scheme by Jahan et al.\ and we show that it has several security vulnerabilities. For instance, the cloud server can get information about encrypted messages by using a stored ciphertext and an update of that ciphertext. As another example, users with writing access are able to decrypt all the messages regardless of their attributes. We discuss the security claims made by Jahan et al.\ and point out the reasons why they do not hold. We also explain that existing schemes can already provide the advantages claimed by Jahan et al. [less ▲]

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See detailGreen exercise is associated with better cell ageing profiles
Olafsdottir, Gunnthora; Cloke, Paul; Epel, Elissa et al

in The European Journal of Public Health (2016, November 01), 26(Suppl 1), 165021

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See detailPrivacy-preserving Friendship-based Recommender Systems
Tang, Qiang; Wang, Jun UL

in IEEE Transactions on Dependable and Secure Computing (2016, November)

Privacy-preserving recommender systems have been an active research topic for many years. However, until today, it is still a challenge to design an efficient solution without involving a fully trusted ... [more ▼]

Privacy-preserving recommender systems have been an active research topic for many years. However, until today, it is still a challenge to design an efficient solution without involving a fully trusted third party or multiple semitrusted third parties. The key obstacle is the large underlying user populations (i.e. huge input size) in the systems. In this paper, we revisit the concept of friendship-based recommender systems, proposed by Jeckmans et al. and Tang and Wang. These solutions are very promising because recommendations are computed based on inputs from a very small subset of the overall user population (precisely, a user’s friends and some randomly chosen strangers). We first clarify the single prediction protocol and Top-n protocol by Tang and Wang, by correcting some flaws and improving the efficiency of the single prediction protocol. We then design a decentralized single protocol by getting rid of the semi-honest service provider. In order to validate the designed protocols, we crawl Twitter and construct two datasets (FMT and 10-FMT) which are equipped with auxiliary friendship information. Based on 10-FMT and MovieLens 100k dataset with simulated friendships, we show that even if our protocols use a very small subset of the datasets, their accuracy can still be equal to or better than some baseline algorithm. Based on these datasets, we further demonstrate that the outputs of our protocols leak very small amount of information of the inputs, and the leakage decreases when the input size increases. We finally show that he single prediction protocol is quite efficient but the Top-n is not. However, we observe that the efficiency of the Top-n protocol can be dramatically improved if we slightly relax the desired security guarantee. [less ▲]

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See detailReport on the Oberwolfach Workshop "Computations in the Cohomology of Arithmetic Groups"
Rahm, Alexander UL

in Oberwolfach Reports (2016, November)

Explicit calculations play an important role in the theoretical development of the cohomology of groups and its applications. It is becoming more common for such calculations to be derived with the aid of ... [more ▼]

Explicit calculations play an important role in the theoretical development of the cohomology of groups and its applications. It is becoming more common for such calculations to be derived with the aid of a computer. This mini-workshop assembled together experts on a diverse range of computational techniques relevant to calculations in the cohomology of arithmetic groups and applications in algebraic K-theory and number theory with a view to extending the scope of computer aided calculations in this area. [less ▲]

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See detailExploiting diversity in future generation satellite systems with optical feeder links
Mengali, Alberto UL; Kayhan, Farbod UL; Shankar, Bhavani UL et al

in Proceedings of the 34TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE (2016, October)

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See detailOptimising time-series experimental design for modelling of circadian rhythms: the value of transient data
Mombaerts, Laurent UL; Mauroy, Alexandre UL; Goncalves, Jorge UL

in IFAC-PapersOnLine (2016, October)

Circadian clocks consist of complex networks that coordinate the daily cycle of most organisms. In light/dark cycles, the clock is synchronized (or entrained) by the environment, which corresponds to a ... [more ▼]

Circadian clocks consist of complex networks that coordinate the daily cycle of most organisms. In light/dark cycles, the clock is synchronized (or entrained) by the environment, which corresponds to a constant rephasing of the oscillations and leads to a steady state regime. Some circadian clocks are endogenous oscillators with rhythms of about 24-hours that persist in constant light or constant darkness. This operating mechanism with and without entrainment provides flexibility and robustness to the clock against perturbations. Most of the clock-oriented experiments are performed under constant photoperiodic regime, overlooking the transitory regime that takes place between light/dark cycles and constant light or darkness. This paper provides a comparative analysis of the informative potential of the transient time-series data with the other regimes for clock modelling. Realistic data were simulated from 2 experimentally validated plant circadian clock models and sliced into several time windows. These windows represent the different regimes that take place before, meanwhile and after the switch to constant light. Then, a network inference tool was used over each window and its capability of retrieving the ground-truth of the network was compared for each window. The results suggest that including the transient data to the network inference technique significally improves its performance. [less ▲]

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See detailCrystallographic and optoelectronic properties of the novel thin film absorber Cu2GeS3
Robert, Erika UL; De Wild, Jessica UL; Colombara, Diego UL et al

in Proceedings of SPIE (2016, September)

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See detailCompressive Sensing Based Energy Detector
Lagunas, Eva UL; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in European Signal Processing Conference (EUSIPCO) (2016, August)

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See detailUmsetzung der Inklusion in der Bildungslandschaft der EU: Anregungen für die Schweiz
Limbach-Reich, Arthur UL

in FACHFORUM SUPPORTED EDUCATION (2016, May 29)

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See detailMMSE Filtering Performance of DH-AF Massive MIMO Relay Systems with Residual Transceiver Impairments
Papazafeiropoulos, Anastasios; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL

in Proceedings of IEEE ICC 2016 (2016, May)

The emerging requirements of the fifth generation (5G) wireless communications are high spectral efficiency, low latency, and ubiquitous coverage. In this direction, Dual-Hop (DH) Amplify-and-Forward (AF ... [more ▼]

The emerging requirements of the fifth generation (5G) wireless communications are high spectral efficiency, low latency, and ubiquitous coverage. In this direction, Dual-Hop (DH) Amplify-and-Forward (AF) relaying has been widely investigated due to its simplicity, low implementation complexity and low transmission delay. However, most existing works assume ideal transceiver hardware which is impractical. In practice, a cost-efficient wireless transceiver has to combat the effects of several inevitable impairments such as high power amplifier nonlinearities, In-phase/Quadrature-phase (I/Q)-imbalance, and oscillator phase noise, which can be only partially compensated using calibration algorithms. In this direction, this paper analyzes the Minimum Mean Square Error (MMSE) filtering performance of a DH-AF Multiple-Input-Multiple-Output (MIMO) wireless system considering the effects of the residual additive impairments at the transmitter and receiver of both hops. Using free probability principles, the MMSE filtering performance of the considered system is studied and a tight lower bound is proposed by taking the effects of residual additive transceiver impairments into account. Our numerical results show that the MMSE filtering performance of the DH-AF massive MIMO relay system significantly degrades and results to saturation in the presence of residual additive transceiver impairments. [less ▲]

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See detailTransmission polarized optical microscopy of short-pitch cholesteric liquid crystal shells
Geng, Yong UL; Noh, Junghyun UL; Lagerwall, Jan UL

in Proceedings of SPIE - The International Society for Optical Engineering (2016, March 07), 9769

We recently demonstrated that colloidal crystal arrangements of monodisperse droplets or shells of planar-aligned cholesteric liquid crystal exhibit intricate patterns of circularly polarized reflection ... [more ▼]

We recently demonstrated that colloidal crystal arrangements of monodisperse droplets or shells of planar-aligned cholesteric liquid crystal exhibit intricate patterns of circularly polarized reflection spots of different colors. The spots appear as a result of photonic cross communication between droplets, hence the patterns reflect the macroscopic arrangement of droplets or shells. Apart from being an interesting optical phenomenon, it offers attractive application opportunities in photonics and beyond, due to the unique characteristics of the patterns. It turns out that the optical quality of shells is much enhanced compared to that of droplets, hence we focus our attention primarily on shells, of varying thickness. Here we analyze and explain the intriguing textures arising when studying planar-aligned short-pitch cholesteric shells in transmission polarizing optical microscopy. In this case, the texture reflects the properties of each individual shell, without any sign of cross communication, yet also this pattern holds some fascinating mysteries. These can only be elucidated by considering all the peculiar optical properties of cholesterics together, as well as the unusual situation given by the spherical shell geometry. [less ▲]

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See detailFostering Reflective Thinking About Information In 5th Graders With Blogs: How Helpful Are Learning Supports?
Thoss, Jennifer; Reuter, Bob UL

in EAPRIL Conference Proceedings (2016, March), (2), 246-257

This study is about fostering media and information literacy and, more precisely, reflective thinking about information in 5th graders. A learning scenario integrating weblogs into a class by providing ... [more ▼]

This study is about fostering media and information literacy and, more precisely, reflective thinking about information in 5th graders. A learning scenario integrating weblogs into a class by providing learning tasks, learning supports and learning resources was elaborated and tested. The class was divided into a test group and a control group, which did not receive learning supports. Over five weeks the pupils ́ degree of reflection was measured by analysing their blog entries by means of pre- defined evaluation criteria. We also observed them while blogging and recorded our impressions. The results showed that, against our expectation, the pupils of the test group were less reflexive in their entries than the ones of the control group. However, we observed that the test group pupils verbally expressed many reflections, which they did not write down. This suggests that our learning scenario comprised of learning tasks, resources and supports promoted reflective thinking about information of all the pupils even if this is not recognisable in their entries. [less ▲]

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See detailDialogic Classroom Talk - Rethinking 'Messy' Classroom Interaction
Arend, Béatrice UL; Sunnen, Patrick UL

in EAPRIL Conference Proceedings (2016, March), (2), 423-434

Over the past decades, dialogic classroom talk has increasingly been acknowledged to be of prime importance for teaching and learning. Many researchers refer to the writings of Mikhail Bakhtin when ... [more ▼]

Over the past decades, dialogic classroom talk has increasingly been acknowledged to be of prime importance for teaching and learning. Many researchers refer to the writings of Mikhail Bakhtin when conceptualising ‘dialogic’ or ‘dialogism’, either as an epistemology or an ontology. In our study we rely on an ontological view of ‘dialogue’ and on the distinction drawn by Bakhtin between ‘authoritative’ and ‘internally persuasive word’ to conduct a sequential analysis (informed by CA) of an extract taken from the film ‘The Class’. Although, the teacher-student interactions at times appear to be ‘messy’ at first sight, our analysis will show that students’ utterances can be considered as an expansion of the subject matter which is accomplished dialogically with their teacher. [less ▲]

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See detailStudy on the quasi Fermi level splitting of Cu(In,Ga)Se2 absorber layers with Cu-rich and Cu-poor composition
Babbe, Finn Sören UL; Choubrac, Léo UL; Siebentritt, Susanne UL

in IEEE Photovoltaic Specialists Conference. Conference Record (2016)

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See detailFormenbestand und strukturelle Asymmetrien der Personalpronomen im Luxemburgischen
Döhmer, Caroline UL

in Zeitschrift fuer Dialektologie und Linguistik. Beihefte (2016)

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See detailPerceived injustice explains pain intensity over and above attentional bias.
Bell, T.; Trost, Z.; van Ryckeghem, Dimitri UL et al

in Journal of Pain (2016), 17(4, 1), 32

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See detailATTENTIONAL BIASES IN PAIN: A META-ANALYSIS OF DOT PROBE RESEARCH
Todd, J.; Sharpe, L.; van Ryckeghem, Dimitri UL et al

in INTERNATIONAL JOURNAL OF BEHAVIORAL MEDICINE (2016), 23(1), 119

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See detailDe la démocratie au Luxembourg, ou : Pourquoi et jusqu’à quel point les référendums de l’art. 51 § 7 Const. sont-ils décisionnels ?
Heuschling, Luc UL

in Actes de la section des sciences morales et politiques de l'Institut grand-ducal (2016)

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See detailCognitive inequalities in later life: Cross-country differences in the education-cognition gradient
Leist, Anja UL

in Gerontologist (2016), 56(S3), 428-429

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See detailTextual Inference with Deep Learning Technique
Adebayo, Kolawole; Di Caro, Luigi; Robaldo, Livio UL et al

in Proc. of the 28th Annual Benelux Conference on Artificial Intelligence (BNAIC2016). (2016)

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See detailEnvironmental stability of highly conductive nominally undoped ZnO layers
Hala, Matej UL; Inoue, Yukari; Kato, Iroki et al

in IEEE Photovoltaic Specialists Conference. Conference Record (2016), 978-1-5090-2724

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See detail“Melanomics”: analysis and integration of whole genomes, transcriptomes and miRNomes of primary melanoma patients
Reinsbach, Susanne; Wienecke, Anke UL; Ginolhac, Aurélien UL et al

in European Journal of Cancer (2016), 61(Suppl.1), 32

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See detailDoctor-patient communication about nutrition on related secondary preventive behaviours, especially for hypertension
Baumann, Michèle UL; Tchicaya, Anastase

in Hypertension (2016)

Inadequate consumption of fruit and vegetables and salt intake are two major factors that can play a role in increased to secondary prevention behaviours. Doctor-patient relationship intervenes on the ... [more ▼]

Inadequate consumption of fruit and vegetables and salt intake are two major factors that can play a role in increased to secondary prevention behaviours. Doctor-patient relationship intervenes on the adherence of these advices. For hypertension, hypercholesterolemia, diabetes, overweight and obesity, our study’s aim was to analyse the associations between the quality of the doctor-patient communication, evaluated in 2013, and patients’ adherence to their general practitioner (GP)’s nutritional advices, between 2008 and 2013. Methods Performed by the National Institute of Cardiac Surgery and Interventional Cardiology in Luxembourg, 4391 patients were contacted. Five years after a coronary angiography, 1289 completed a self-rating questionnaire assessing the GP’Com-5 items scale (Cronbach 0.87). The variables were analysed with a multiple logistic regression model. Results Patients declared that 57.9% reduced or stopped their consumption of salt intake, whereas 65% increased their consumption of fresh fruits and vegetables. Around 37% of the patients reported having made changes following the advice of their doctor. An increased consumption of fresh fruits and vegetables was linked with the quality of doctor-patient communication when patients were hypertension (odd ratio (OR) = 1.084, IC 95%, [1.017-1.157]), overweight (1.081 [1.013-1.155]), obesity (OR = 1.130 [1.056-1.209]), hypercholesterolemia (OR = 1.102 [1.033–1.175]) and diabetes (OR = 1.103 [1.029-1.181]). The decreased of salt intake consumption was associated with the quality of physician-patient communication when the patient was hypertension (OR = 1.102 [1.034 – 1.176]). Conclusion Doctor-patient communication is a relevant determinant in obtaining a favourable behavioural outcome, especially on nutrition. The rehabilitation program must promote more exchange and telephone assistance to develop a mutual engagement. [less ▲]

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See detailReified Input/Output logic - a position paper
Robaldo, Livio UL; Sun, Xin UL

in proceedings of Workshop on Artificial Intelligence for Justice (AI4J), collocated at the 22nd European Conference on Artificial Intelligence (ECAI 2016) (2016)

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See detailSimCoTest: A Test Suite Generation Tool for Simulink/Stateflow Controllers
Matinnejad, Reza UL; Nejati, Shiva UL; Briand, Lionel UL et al

in Proceedings of the 38th International Conference on Software Engineering (2016)

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See detailAutomated Test Suite Generation for Time-Continuous Simulink Models
Matinnejad, Reza UL; Nejati, Shiva UL; Briand, Lionel UL et al

in proceedings of the 38th International Conference on Software Engineering (2016)

All engineering disciplines are founded and rely on models, al- though they may differ on purposes and usages of modeling. Inter- disciplinary domains such as Cyber Physical Systems (CPSs) seek approaches ... [more ▼]

All engineering disciplines are founded and rely on models, al- though they may differ on purposes and usages of modeling. Inter- disciplinary domains such as Cyber Physical Systems (CPSs) seek approaches that incorporate different modeling needs and usages. Specifically, the Simulink modeling platform greatly appeals to CPS engineers due to its seamless support for simulation and code generation. In this paper, we propose a test generation approach that is applicable to Simulink models built for both purposes of simulation and code generation. We define test inputs and outputs as signals that capture evolution of values over time. Our test gener- ation approach is implemented as a meta-heuristic search algorithm and is guided to produce test outputs with diverse shapes according to our proposed notion of diversity. Our evaluation, performed on industrial and public domain models, demonstrates that: (1) In con- trast to the existing tools for testing Simulink models that are only applicable to a subset of code generation models, our approach is applicable to both code generation and simulation Simulink mod- els. (2) Our new notion of diversity for output signals outperforms random baseline testing and an existing notion of signal diversity in revealing faults in Simulink models. (3) The fault revealing ability of our test generation approach outperforms that of the Simulink Design Verifier, the only testing toolbox for Simulink. [less ▲]

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See detailInequality in old age cognition across the world
Olivera, Javier; Leist, Anja UL; Chauvel, Louis UL

in PAA website (2016)

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See detailCohort factors impinging on suicide rates in the United States, 1990-2010
Chauvel, Louis UL; Leist, Anja UL; Smith, Herbert

in PAA server (2016)

We use CDC microdata on cause of death and CPS data on populations by age to create suicide rates for five-year age groups at five-year intervals, further cross-classified by race/ethnicity, education ... [more ▼]

We use CDC microdata on cause of death and CPS data on populations by age to create suicide rates for five-year age groups at five-year intervals, further cross-classified by race/ethnicity, education, and marital status. We examine the suicide history 1990-2010 of U.S. birth cohorts, net of age and cohort linear trends. These de-trended cohort deviations follow familiar patterns: most pronounced in the Baby Boom, least pronounced during the Baby Bust, they illustrate the so-called Easterlin effect. Suicide rates for women show similar patterns as suicide patterns for men. We show persistence of those effects net of micro factors (especially education and marriage) implicated in suicide behavior and correlated at the macro level with relative cohort size. Analysis of suicide patterns over time for high- and low-educated men and women shows that white men with low education face a sharp increase, significantly above the linear time trends, in suicide rates among cohorts born between 1955 and 1970. This bump is mostly unrelated to secular trends of increasing average educational attainment rates, at least if no interaction between age and cohort is involved in the explanation. No obvious pattern related to cohort size is found for African-American high- and low-educated men, which makes sense given the very different historical dynamics for this minority sub-population. [less ▲]

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See detailInteroception in anorexia nervosa: evidence at cortical and self-report levels
Lutz, Annika UL; Schulz, André UL; Voderholzer, Ulrich et al

in Appetite (2016), 107

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See detailFood, eating and emotions: les liaisons dangereuses
Vögele, Claus UL

in Journal of Behavioral Addictions (2016), 5(Suppl 1), 3

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See detailIs income equality also better for your cognitive health? A multilevel analysis on trajectories of cognitive function at older ages
Leist, Anja UL; Chauvel, Louis UL

in PAA website (2016)

This paper contributes to research on contextual associations with older-age cognitive function by investigating to which extent country-level income inequality is associated with older-age cognitive ... [more ▼]

This paper contributes to research on contextual associations with older-age cognitive function by investigating to which extent country-level income inequality is associated with older-age cognitive function and decline. Data came from the Survey of Health, Ageing and Retirement in Europe (SHARE), providing information on cognitive function (fluency, immediate and delayed recall) of respondents aged 50-80 years coming from a total of 16 European countries that participated in at least two waves of SHARE. A total of 44,303 observations were available at first and second measurement, 13,509 observations at third measurement, and 9,736 observations at fourth measurement. Three-level hierarchical models (measurements nested within individuals nested within countries) were run, showing that income inequality was negatively associated with cognitive level but not with decline. The findings suggest that income inequality is not associated with cognitive trajectories. Mechanisms of maintaining cognitive function at older ages may not be susceptible to country-level income inequalities. [less ▲]

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See detailPhase-error correction by single-phase phase-locked loops based on transfer delay
Kobou Ngani, Patrick UL; Hadji-Minaglou, Jean-Régis UL; Marso, Michel UL et al

in Journal of Electrical & Electronic Systems (2015, November 04)

Comparative studies of different single-phase phase-locked loops (PLL) algorithms have been made. They show that the PLL based on sample delay (dPLL), presents the lowest computational load and is as ... [more ▼]

Comparative studies of different single-phase phase-locked loops (PLL) algorithms have been made. They show that the PLL based on sample delay (dPLL), presents the lowest computational load and is as robust as the three-phase synchronous reference frame PLL dqPLL by input signal amplitude and phase variations. Its weakness appears when the input signal frequency differs from its rated frequency: It depicts a steady error on the calculated signal phase-angle. After a brief review of the dqPLL which constitutes debase structure of the dPLL, the following work will present three methods that improve the phase detection accuracy of dPLL. It is shown that the modifications brought in the original structure do not influence the robustness and stability of the algorithm but reduce the phase angle offset error by input signal frequency variation. This is corroborated by tests including not only the fundamental input voltage disturbance like amplitude, phase and frequency variation but also harmonic voltage distortion. [less ▲]

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See detailAdaptive Activity and Context Recognition using Multimodal Sensors in Smart Devices
Faye, Sébastien UL; Frank, Raphaël UL; Engel, Thomas UL

in Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering - Mobile Computing, Applications, and Services (2015, November)

The continuous development of new technologies has led to the creation of a wide range of personal devices embedded with an ever increasing number of miniature sensors. With accelerometers and ... [more ▼]

The continuous development of new technologies has led to the creation of a wide range of personal devices embedded with an ever increasing number of miniature sensors. With accelerometers and technologies such as Bluetooth and Wi-Fi, today's smartphones have the potential to monitor and record a complete history of their owners' movements as well as the context in which they occur. In this article, we focus on four complementary aspects related to the understanding of human behaviour. First, the use of smartwatches in combination with smartphones in order to detect different activities and associated physiological patterns. Next, the use of a scalable and energy-efficient data structure that can represent the detected signal shapes. Then, the use of a supervised classifier (i.e. Support Vector Machine) in parallel with a quantitative survey involving a dozen participants to achieve a deeper understanding of the influence of each collected metric and its use in detecting user activities and contexts. Finally, the use of novel representations to visualize the activities and social interactions of all the users, allowing the creation of quick and easy-to-understand comparisons. The tools used in this article are freely available online under a MIT licence. [less ▲]

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See detailSome remarks on the influence of temperature-variations, non-linearities, repeatability and ageing on modal-analysis for structural health monitoring of real bridges
Maas, Stefan UL; Schommer, Sebastian UL; Nguyen, Viet Ha UL et al

in MATEC Web of Conferences (2015, October 19), 24(Article No. 05006),

Structural Health Monitoring (SHM) intends to identify damage by changes of characteristics as for instance the modal parameters. The eigenfrequencies, mode-shapes and damping-values are either directly ... [more ▼]

Structural Health Monitoring (SHM) intends to identify damage by changes of characteristics as for instance the modal parameters. The eigenfrequencies, mode-shapes and damping-values are either directly used as damage indicators or the changes of derived parameters are analysed, such as e.g. flexibilities or updated finite element models. One common way is a ontinuous monitoring under environmental excitation forces, such as wind or traffic, i.e. the so-called output-only modal analysis. Alternatively, a forced measured external excitation in distinct time-intervals may be used for input-output modal analysis. Both methods are limited by the precision or the repeatability under real-life conditions at site. The paper will summarize everal field tests of artificially step by step damaged bridges prior to their final demolishment and it will show the changes of eigenfrequencies due to induced artificial damage. Additionally, some results of a monitoring campaign of a healthy bridge in Luxembourg are presented. Reinforced concrete shows non-linear behaviour in the sense that modal parameters depend on the excitation force amplitude, i.e. higher forces lead often to lower eigenfrequencies than smaller forces. Furthermore, the temperature of real bridges is neither constant in space nor in time, while for instance the stiffness of asphalt is strongly dependant on it. Finally, ageing as uch can also change a bridge’s stiffness and its modal parameters, e.g. because creep and hrinkage of concrete or ageing of elastomeric bearing pads influence their modulus of elasticity. These effects cannot be considered as damage, though they influence the measurement of modal parameters and hinder damage detection. [less ▲]

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See detailRobot and Human safety in a semi-automated assembly workspace
Ahmad, Rafiq UL

in IEEE transactions (2015, October 02)

Robots used for automation in industries should be able to react to any uncomfortable situations in their vicinity in order to avoid harming humans, working product, other machinery and itself. The ... [more ▼]

Robots used for automation in industries should be able to react to any uncomfortable situations in their vicinity in order to avoid harming humans, working product, other machinery and itself. The manipulator robots might not only be able to predict potential collisions but should also be able to take intelligent decisions for automatically avoiding them with a safe detour around the obstacles. This paper introduces a 3D-Time- of-Flight sensor based SARPP algorithm which automatically plans path for the robot in a human robot collaborative semi- automated assembly environment. The application of algorithm can be foreseen in more complex Human-Robot-Collaborative industrial environment where the safety of human as well as robots are the highest priority. [less ▲]

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See detailUser Required? On the Value of User Research in the Digital Humanities
Kemman, Max UL; Kleppe, Martijn

in Linköping Electronic Conference Proceedings (2015, August 26), (116), 63-74

Although computational tools play an increasingly important role in the humanities, adoption of tools by scholars does not always reach its potential. One approach to this problem is user research to ... [more ▼]

Although computational tools play an increasingly important role in the humanities, adoption of tools by scholars does not always reach its potential. One approach to this problem is user research to uncover the needs of the users. However, it is uncertain whether such user requirements can be generalized to a wider group of humanities scholars, and whether users are able to explicate their requirements for methodological innovation. We ask what the role of user research is in the Digital Humanities by discussing gathered user requirements for two projects. We categorized the requirements as within- or out-of-scope of the projects’ goals, and found a tension between the specificity of humanities’ research methods, and generalizability for a broader applicable tool. With the out-of-scope requirements we are able to map the wider research workflow, showing DH tools will most likely take a spot in the wider workflow, and that it is infeasible to create a tool for the entire workflow that is generic enough for a larger user group. However, the within-scope requirements led to features that were sufficiently generic for the tool to be adopted, also for unintended purposes. These insights show user research has a clear benefit for DH projects. [less ▲]

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See detailValue Stream Management in the "Lean Manufacturing Laboratory"
Oberhausen, Christof UL; Plapper, Peter UL

in Procedia CIRP (2015, July), 32

The University of Luxembourg has recently launched its learning factory, the “Lean Manufacturing Laboratory”. With the help of this manual assembly line, students gain valuable insights in the operation ... [more ▼]

The University of Luxembourg has recently launched its learning factory, the “Lean Manufacturing Laboratory”. With the help of this manual assembly line, students gain valuable insights in the operation of a manufacturing line as well as in buffer, waste and congestion management. Currently, one of the main research topics at the University of Luxembourg in the field of Lean Management is the further development of the method Value Stream Management (VSM). The application of VSM in the “Lean Manufacturing Laboratory” with a projected focus on industry and service sectors reveals the need for a standardized VSM approach. Thus, one of the research objectives is the development of a common VSM method accompanied by standardized software and process interfaces to ensure robust product and information flows within a company and also throughout supply chains. On the way towards a VSM method as standard, existing VSM approaches have to be investigated and validated. By a detailed comparison of existing VSM approaches, all necessary fields of action for the development of a standardized Value Stream Management approach are shown. [less ▲]

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See detailEvaluation of basic motor competencies in primary school children: Development of a test instrument
Scheuer, Claude; Bund, Andreas UL; Herrmann, Christian

in Revista Espanola de Educación Física y Deporte (2015, July), 410 (Supl.)(3), 486

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See detailCu2SnS3-based thin film solar cell from electrodeposition-annealing route
Robert, Erika UL; De Wild, Jessica UL; Dale, Phillip UL

in IEEE Proceedings (2015, June)

Cu2SnS3 is a new emerging material for thin film photovoltaics, composed of three abundant and non toxic elements. Its p-type conductivity, bandgap of 0.93 eV and absorption coefficient above 104 cm-1 ... [more ▼]

Cu2SnS3 is a new emerging material for thin film photovoltaics, composed of three abundant and non toxic elements. Its p-type conductivity, bandgap of 0.93 eV and absorption coefficient above 104 cm-1 make it a promising absorber layer for p-n heterojunction devices. In this study, the Cu2SnS3 absorber is synthesized from electroplated stacked Cu-Sn precursors further annealed in chalcogen atmosphere (S and SnS). The electroplating has been processed on upscaled 45 x 50 mm2 Mo-coated soda-lime glass substrates on which the metallic layers seem to delaminate easily from the substrate due to increased stress between them. To reduce this stress the precursors are subjected to pre-alloying treatments. The effects of pre-alloying are investigated in terms of final absorber morphology, composition and crystal structure. Precursors are annealed at 250°C and 350°C. The prealloying at 350°C is far above the melting point of Sn around 230°C and these samples show de-wetting. The as-deposited and 250°C pre-alloyed samples are processed further into absorber layers and solar cells. The finished absorber layers show mainly monoclinic Cu2SnS3. Absorbers completed into devices show a device power conversion efficiency of 0.64%. The spectral response suggests the existence of two bandgaps, consistent with previous results. [less ▲]

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See detailMining Patterns of Unsatisfiable Constraints to Detect Infeasible Paths
DING, SUN; TAN, HEE BENG KUAN; Shar, Lwin Khin UL

in Automation of Software Test (AST 2015) (2015, May)

Detection of infeasible paths is required in many areas including test coverage analysis, test case generation, security vulnerability analysis, etc. Existing approaches typically use static analysis ... [more ▼]

Detection of infeasible paths is required in many areas including test coverage analysis, test case generation, security vulnerability analysis, etc. Existing approaches typically use static analysis coupled with symbolic evaluation, heuristics, or path-pattern analysis. This paper is related to these approaches but with a different objective. It is to analyze code of real systems to build patterns of unsatisfiable constraints in infeasible paths. The resulting patterns can be used to detect infeasible paths without the use of constraint solver and evaluation of function calls involved, thus improving scalability. The patterns can be built gradually. Evaluation of the proposed approach shows promising results. [less ▲]

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See detailVerification and Implementation of Pseudo-Random-Binary-Sequences for Online Determination of Grid Impedance Spectrum
Tewari, Udit; Neshvad, Surena UL; Sachau, Jürgen UL

in The Renewable Energy & Power Quality Journal (2015, March 25)

The number of inverter based distributed power generators connected to the power network has rapidly grown in recent years. The consequence of this phenomenon is an increasingly complex distribution grid ... [more ▼]

The number of inverter based distributed power generators connected to the power network has rapidly grown in recent years. The consequence of this phenomenon is an increasingly complex distribution grid, requiring advanced and intelligent monitoring and observation tools in order to guarantee satisfactory power quality and reliability. This paper describes a novel power line impedance estimation method, implementing an innovative technique based on modifications of the Pulse Width Modulator’s pulse pattern on the inverters, in order to generate Pseudo-Random Binary Sequence based pilot signals. The stimuli are generated at different locations in the distribution grid, and detected at the transformer sub-station through cross correlation between the received distorted signal and the sequence, the parameters of the propagation channel can be estimated. Simulations in typical grid situations verify that the proposed algorithm is robust to a realistic environment and would [less ▲]

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See detailDie aktuellen Familienkonzepte der Europäischen Kommission und ihre Umsetzung in der Volkszählung 2011 – Ein Erfahrungsbericht aus Luxemburg
Heinz, Andreas UL; Willems, Helmut UL

in DGD-Online-Publikation (2015, March 13), (01/2015), 114-121

In der luxemburgischen Volkszählung 2001 wurde die Haushaltszusammensetzung erhoben, indem abgefragt wurde, in welcher Beziehung jedes Haushaltsmitglied zur Referenzperson steht. Diese Frage ist leicht zu ... [more ▼]

In der luxemburgischen Volkszählung 2001 wurde die Haushaltszusammensetzung erhoben, indem abgefragt wurde, in welcher Beziehung jedes Haushaltsmitglied zur Referenzperson steht. Diese Frage ist leicht zu beantworten und die Methode wird bis heute in zahlreichen Umfragen genutzt. Das Hauptproblem dieser Methode besteht darin, dass nicht erhoben wird, in welcher Beziehung die Nichtreferenzpersonen untereinander stehen. Damit ist die Information über die Haushaltszusammensetzung davon abhängig, wer den Fragebogen ausfüllt: Über ein und denselben Haushalt können unterschiedliche Angaben vorliegen, je nachdem ob die Mutter, der Großvater oder eine sonstige Person den Fragebogen ausfüllt. Diese Methode ist für die familiensoziologische Forschung wenig ergiebig und sie reicht nicht aus, um die Vorgaben der EU für die Volkszählungen 2011 zu erfüllen. Daher wurden zum einen Antwortkategorien ergänzt und zum anderen wurden die Beziehungen von jedem Haushaltsmitglied zu jedem anderen erhoben. Bei der ersten Umsetzung im Jahr 2011 bedeutet dies einen höheren Aufwand für die Aufbereitung der Daten vor der Eingabe sowie für die Einteilung gemäß der EU-Klassifikation. Allerdings ist mit dieser Methode ein deutlich höherer Informationsgehalt verbunden. Des Weiteren ist davon auszugehen, dass der Aufwand für erneute Anwendung im Jahr 2021 deutlich geringer ausfällt, sofern mehr Personen den Fragebogen der Volkszählung online ausfüllen und die EU-Klassifikation beibehalten wird. Inhaltlich eignet sich die EU-Klassifikation sehr gut, um familiensoziologische Fragen zu beantworten. Exemplarisch wird dies anhand unterschiedlichen private Übergänge von der Jugend zum Erwachsenenalter sowie der Übergänge vom mittleren zum höheren Erwachsenenalter der luxemburgischen und portugiesischen Bevölkerung Luxemburgs gezeigt. [less ▲]

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See detailBluetooth Low Energy Robustness Analysis for V2V Communications
Bronzi, Walter UL

in Ulmer Informatik-Berichte (2015, March)

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See detailAdaptive methods for multiscale fracture
Bordas, Stéphane UL; Kerfriden, Pierre; Akbari, Ahmad et al

in International Journal of Engineering Science (2015, January 01)

Adaptive methods for multiscale fracture In this work, we discuss two classes of methods to reduce the complexity of (multi scale) fracture simulations. In a first part, we discuss algebraic model ... [more ▼]

Adaptive methods for multiscale fracture In this work, we discuss two classes of methods to reduce the complexity of (multi scale) fracture simulations. In a first part, we discuss algebraic model reduction. We show that algebraic model reduction such as the proper orthogonal decomposition cannot be used directly because of the lack of corelation introduced by the damage or cracks. We demonstrate the use of proper orthogonal decompositions by subdomains as a candidate to reduce computational expenses in non-linear fracture simulations whilst controlling the error level. We then consider algebraic model reduction, namely the proper orthogonal decomposition(POD) to drastically reduce the computational time associated with computing the response of representative volume elements (RVEs) used in homogenization, e.g. by the FE2 method. The snapshots are obtained by solving the RVE boundary value problem for various loading paths. To speed-up the computations, system approximation through the discrete empirical interpolation (DEIM) is used and allows the evaluation of the internal forces for only a small subset of the elements making the RVE structure. In a second part, we propose an adaptive hybrid multiscale method for modelling fracture in a heterogeneous material that is composed of orthotropic grains with cohesive interfaces between the grains. Instead of a direct solver, FE2 method [1] based on homogenisation is employed in order to compute the effective behaviour of the heterogeneous microscopic material on the coarser scale. At this scale the modelling error due to the homogenisation is still low [3]. The coarse scale is discretized with unstructured triangular finite elements, and adaptive mesh refinement is used to control the discretizsation error. While the mesh refinement keeps the discretisation error with in a certain range, the modelling error increases due to the fact that by refining the coarse elements, the scale separation assumption which is a key issue for homogenisation may no longer be fulfilled [4]. Whereas the modelling error is inversely proportional to the size of the coarse elements, a critical element size can be found that corresponds to the critical value of the modelling error. A critical zone emerges when the size of a coarse element reaches the critical size, or if the underlying representative volume element of the microstructure loses stability due to localisation (lack of scale separation). Thereafter, a zoom-in process is triggered that replaces the corresponding coarse elements of the critical zone with high resolution microscale mesh to which it glues the coarse scale mesh through a strong coupling technique using Lagrange multipliers [5]. The high resolution region can gradually be extended to include the newly emerging critical zones. A local arc-length technique is adopted to trace the highly non-linear curve of the global load-displacement by controlling the opening of microscopic cohesive cracks in the fully resolved regions. The proposed adaptive multiscale method allows us to introduce progressive discrete micro cracks at the macroscale. The unstructured mesh enables us to model problems with non-regular shapes, and the arc-length method, defined over multiple scales, allows the regularisation of softening problems that are treated in quasi-statics. We exercise this method on the simulation of polycrystalline fracture, where each grain is considered orthotropic and compare results to direct numerical simulation. [less ▲]

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See detailMulticast multigroup beamforming for per-antenna power constrained large-scale arrays
Christopoulos, Dimitrios UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC (2015), 2015-August

Large in the number of transmit elements, multi-antenna arrays with per-element limitations are in the focus of the present work. In this context, physical layer multigroup multicasting under per-antenna ... [more ▼]

Large in the number of transmit elements, multi-antenna arrays with per-element limitations are in the focus of the present work. In this context, physical layer multigroup multicasting under per-antenna power constrains, is investigated herein. To address this complex optimization problem low-complexity alternatives to semi-definite relaxation are proposed. The goal is to optimize the per-antenna power constrained transmitter in a maximum fairness sense, which is formulated as a non-convex quadratically constrained quadratic problem. Therefore, the recently developed tool of feasible point pursuit and successive convex approximation is extended to account for practical per-antenna power constraints. Interestingly, the novel iterative method exhibits not only superior performance in terms of approaching the relaxed upper bound but also a significant complexity reduction, as the dimensions of the optimization variables increase. Consequently, multicast multigroup beamforming for large-scale array transmitters with per-antenna dedicated amplifiers is rendered computationally efficient and accurate. A preliminary performance evaluation in large-scale systems for which the semi-definite relaxation constantly yields non rank-1 solutions is presented. © 2015 IEEE. [less ▲]

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See detailFormal Specification, Verification, and Implementation of Fault-Tolerant Systems using EventML
Rahli, Vincent UL; Guaspari, David; Bickford, Mark et al

in EASST (2015)

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See detailFeasibility study of full-duplex relaying in satellite networks
Bhavani Shankar, M. R.; Zheng, G.; Maleki, Sina UL et al

in IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC (2015), 2015-August

With the successful implementation of full-duplex radio prototypes, traditional orthogonal half-duplex communications is deemed to be inefficient in certain terrestrial applications. While full-duplex ... [more ▼]

With the successful implementation of full-duplex radio prototypes, traditional orthogonal half-duplex communications is deemed to be inefficient in certain terrestrial applications. While full-duplex techniques are gaining interest in terrestrial communications, thanks to the trend of short-distance and low-power transmissions, their application to satellite communications has drawn little attention. Motivated by this, the paper explores the use of the full-duplex relaying operation on-board the satellite in a DVB-S2 compliant network. Self-interference, whose management is the key component of a full-duplex communication, is the focus of study in this paper. Modelling the effects of self-interference and power amplifier nonlinearities on the quality of the received signal in undertaken. Subsequently, closed-form expressions for the various interference components are derived. The numerical evaluations of derived expressions rely on realistic link budgets and indicate substantial gains in spectral efficiency when self-interference can be well calibrated and measured. This confirms that the satellite full-duplex communications could be a promising solution for the efficient use of satellite spectrum, at least from a technical point of view. © 2015 IEEE. [less ▲]

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See detailSafe and Automated Assembly Process using Vision assisted Robot Manipulator
Ahmad, Rafiq UL; Plapper, Peter UL

in Procedia CIRP (2015)

Many manufacturing industries especially small and medium size (SMEs) industries are reluctant to automatize their production using robots. This is due to the fact that mostly industrial robots are not ... [more ▼]

Many manufacturing industries especially small and medium size (SMEs) industries are reluctant to automatize their production using robots. This is due to the fact that mostly industrial robots are not properly equipped to recognize their surrounding and take intelligent decisions regarding path planning especially for low volume, flexible production with versatile production lines. The proposed idea is that a robot manipulator performing assembly or disassembly tasks should be able to predict potential collisions even with unknown obstacles and must be able to prevent i.e. react automatically for safe detour around obstacle. Currently, industrial robots have tactile sensing abilities, which detect collisions after a real contact but the existing proposals for its avoidance are either computationally expensive, need prior information about the obstacles or not very well adapted to the safety standards. Therefore, this paper introduces a ToF sensor based information collection and intelligent decision methodology in order to localize the un-known, un-programmed obstacles and propose a safe peg-in-hole automated assembly process. In the case of collisions, the proposed method will provide various solutions and decides for the best solution according to the scenario on-hand. The proposed solution is quick and robust and currently applied for static environment, whereas dynamic obstacles will be treated in future. [less ▲]

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See detailFull scale BWR containment loca response test at the INKA test facility
Wagner, T.; Leyer, Stephan UL

in International Conference on Nuclear Engineering, Proceedings, ICONE (2015), 2015-January

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify ... [more ▼]

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify the functionality and performance of the KERENA safety concept required for the transient and accident management, the test facility "Integral Teststand Karlstein" (INKA) was built at Karlstein (Germany). It is a mock-up of the KERENA boiling water reactor containment, with integrated pressure suppression system. The complete chain of passive safety components is available. The passive components and the levels are represented in full scale. The volume scaling of the containment compartments is approximately 1:24. The reactor pressure vessel (RPV) is simulated via the steam accumulator of the Karlstein Large Valve Test Facility. This vessel provides an energy storage capacity of approximately 1/6 of the KERENA RPV and is supplied by a Benson boiler with a thermal power of 22 MW. With respect to the available power supply, the containment- and system-sizing of the facility is by far the largest one of its kind worldwide. From 2009 to 2012, several single component tests were conducted (Emergency Condenser, Containment Cooling Condenser, Core Flooding System etc.). On March 21st, 2013, the worldwide first large-scale only passively managed integral accident test of a boiling water reactor was simulated at INKA. The integral test measured the combined response of the KERENA passive safety systems to the postulated initiating event was the "Main Steam Line Break" (MSLB) inside the Containment with decay heat simulation. The results of the performed integral test (MSLB) showed that the passive safety systems alone are capable to bring the plant to stable conditions meeting all required safety targets with sufficient margins. Therefore the test verified the function of those components and the interplay between them as response to an anticipated accident scenario. The test provided evidence that the INKA is worldwide the first large scale test facility to perform integral verification tests of passive safety concepts under plant-like scaling and thermodynamic conditions. Hence, the test facility also shows that it is capable to perform containment response tests for existing Generation II BWRs (with active safety systems) and advanced (passive) reactor designs besides KERENA. These test results can be used to strengthen existing containment codes with regard to heat transfer, natural circulation, gas- and temperature stratification and others. Copyright © 2015 by JSME. [less ▲]

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See detailIncome inequality and health: Age-related health gains for those better-off, in more equal societies
Chauvel, Louis UL; Leist, Anja UL

in Gerontologist (2015), 55(Suppl 2), 459-460

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See detailGeneralized direct predistortion with adaptive crest factor reduction control
Piazza, Roberto UL; Bhavani Shankar, M. R.; Ottersten, Björn UL

in ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings (2015), 2015-August

Efficient power amplification is inherently a non linear operation that introduces unwanted interference in the amplified signal. Strong inter-symbol interference is generated when the amplifier non ... [more ▼]

Efficient power amplification is inherently a non linear operation that introduces unwanted interference in the amplified signal. Strong inter-symbol interference is generated when the amplifier non linearity is combined with channel memory effects. Further, signals with very high peak to average power ratio, typical of multiple carrier systems, are even more sensitive to the non linearities resulting in severe distortion effects. Signal pre-clipping (crest factor reduction) and predistortion are conventional countermeasure techniques to reduce the generated non linear distortion and improve power and spectral efficiency. In this work, novel optimization methods for predistortion and pre-clipping are analytically derived for a general non-linear communication channel with memory. A combined architecture in which crest factor reduction is followed by signal predistortion is proposed and the parameters are estimated resorting to iterative algorithms based on least squares method. Performance evaluation of the estimation techniques shows the effectiveness of the derived algorithms and significant gain compared to previously known methods. © 2015 IEEE. [less ▲]

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See detailA randomized controlled non-inferiority trial of primary care-based facilitated access to an alcohol reduction website (EFAR-FVG): preliminary results
Struzzo, Pierluigi; Vedova, Roberto; Ferrante, Donatella et al

in Addiction Science & Clinical Practice (2015), 10(Suppl 2), 29

Background The effectiveness of brief interventions for risky drinkers by GPs is well documented.[1] However, implementation levels remain low. Facilitated access to an alcohol reduction website offers an ... [more ▼]

Background The effectiveness of brief interventions for risky drinkers by GPs is well documented.[1] However, implementation levels remain low. Facilitated access to an alcohol reduction website offers an alternative to standard face-to-face intervention, but it is unclear whether it is as effective.[2] This study evaluates whether online brief intervention, through GP facilitated access to an alcohol reduction website for risky drinkers, is not inferior to the face-to-face brief intervention conducted by GPs. Material and methods In a northern Italy region participating GPs actively encouraged all patients age 18 attending their practice, to access an online screening website based on AUDIT-C.[3] Those screening positive underwent a baseline assessment with the AUDIT-10[4] and EQ-5D[5] questionnaires and subsequently, were randomly assigned to receive either online counselling on the alcohol reduction website (intervention) or face-to-face intervention based on the brief motivational interview[6] by their GP (control). Follow-up took place at 3 and 12 months and the outcome was calculated on the basis of the proportion of risky drinkers in each group according to the AUDIT-10. Results More than 50% (n= 3974) of the patients who received facilitated access logged-on to the website and completed the AUDIT-C. Just under 20% (n = 718) screened positive and 94% (n= 674) of them completed the baseline questionnaires and were randomized. Of the 310 patients randomized to the experimental Internet intervention, 90% (n = 278) logged-on to the site. Of the 364 patients of the control group, 72% (263) were seen by their GP. A follow-up rate of 94% was achieved at 3 months. Conclusions The offer of GP facilitated access to an alcohol reduction website appears to be an effective way of identifying risky drinkers and enabling them to receive brief intervention. [less ▲]

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See detailLogic and Games for Ethical Agents in Normative Multi-agent Systems
sun, xin; Robaldo, Livio UL

in proc. of 13th European Conference on Multi-Agent Systems/3rd International Conference on Agreement Technologies (2015)

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See detailPower control in cognitive radio networks using cooperative modulation and coding classification
Tsakmalis, Anestis UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST (2015), 156

In this paper, a centralized Power Control (PC) scheme aided by interference channel gain learning is proposed to allow a Cognitive Radio (CR) network to access the frequency band of a Primary User (PU ... [more ▼]

In this paper, a centralized Power Control (PC) scheme aided by interference channel gain learning is proposed to allow a Cognitive Radio (CR) network to access the frequency band of a Primary User (PU) operating based on an Adaptive Coding and Modulation (ACM) protocol. The main idea is the CR network to constantly probe the band of the PU with intelligently designed aggregated interference and sense whether the Modulation and Coding scheme (MCS) of the PU changes in order to learn the interference channels. The coordinated probing is engineered by the Cognitive Base Station (CBS), which assigns appropriate CR power levels in a binary search way. Subsequently, each CR applies a Modulation and Coding Classification (MCC) technique and sends the sensing information through a control channel to the CBS, where all the MCC information is combined using a fusion rule to acquire an MCS estimate of higher accuracy and monitor the probing impact to the PU MCS. After learning the normalized interference channel gains towards the PU, the CBS selects the CR power levels to maximize total CR network throughput while preserving the PU MCS and thus its QoS. The effectiveness of the proposed technique is demonstrated through numerical simulations. © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2015. [less ▲]

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See detailComputational Complexity of Input/Output Logic
Sun, Xin UL; Ambrossio, Diego Agustin UL

in Lecture Notes in Computer Science (2015), 9426

Input/output logics are abstract structures designed to represent conditional norms. The complexity of input/output logic has been sparsely developed. In this paper we study the complexity of input/output ... [more ▼]

Input/output logics are abstract structures designed to represent conditional norms. The complexity of input/output logic has been sparsely developed. In this paper we study the complexity of input/output logics. We show that the lower bound of the complexity of the fulfillment problem of 4 input/output logics is coNP, while the upper bound is either coNP or P^NP. [less ▲]

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See detailMotivations to care and health motivations: A qualitative study exploring the experience of family caregivers
Spitz, Elisabeth; Bucki; Baumann, Michèle UL

in European Health Psychologist (The) (2015)

Background. The COM-B system adapted to family caregivers analyses health capability through capabilities, opportunities, and motivations. Focusing on motivations, this study investigated the motivations ... [more ▼]

Background. The COM-B system adapted to family caregivers analyses health capability through capabilities, opportunities, and motivations. Focusing on motivations, this study investigated the motivations to be a family caregiver and the motivations to maintain one’s own health. Methods. Semi-structured interviews were conducted with 14 caregivers of stroke victims (France: n=8; Luxembourg: n=6; 50% male; age 63.6±10.1) about how they preserve their health and their resources to attain optimal health. Verbatims about their motivations to care for their relative and their motivation to maintain their own health were open-coded. Items were built and validated by consensus with an expert group. Findings. Motivations to care for a relative included the sense of duty, fear of guilt or deception, perceived need and feelings like love. The motivations to maintain personal health were intrinsic (self-; family-oriented), related to caregiving, and extrinsic (induced by relatives and material needs) and encompass amotivation. Discussion. It is relevant to integrate feelings, anticipated regret, moral norms and health value to the COM-B system adapted to family caregivers. Identifying their contribution to health capability will help orient psycho-educational interventions implementation. [less ▲]

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See detailAnticipation of brain shift in Deep Brain Stimulation automatic planning
Bilger, Alexandre UL; Cotin, Stephane; Duriez, Christian et al

in IEEE Engineering in Medicine and Biology Society (2015)

Deep Brain Stimulation is a neurosurgery procedure consisting in implanting an electrode in a deep structure of the brain. This intervention requires a preoperative planning phase, with a millimetric ... [more ▼]

Deep Brain Stimulation is a neurosurgery procedure consisting in implanting an electrode in a deep structure of the brain. This intervention requires a preoperative planning phase, with a millimetric accuracy, in which surgeons decide the best placement of the electrode depending on a set of surgical rules. However, brain tissues may deform during the surgery because of the brain shift phenomenon, leading the electrode to mistake the target, or moreover to damage a vital anatomical structure. In this paper, we present a patient-specific automatic planning approach for DBS procedures which accounts for brain deformation. Our approach couples an optimization algorithm with FEM based brain shift simulation. The system was tested successfully on a patient-specific 3D model, and was compared to a planning without considering brain shift. The obtained results point out the importance of performing planning in dynamic conditions. [less ▲]

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See detailRecessions, unemployment and the brain: Do individual and aggregate economic shocks prior to retirement leave a cognitive ‘scar’?
Hessel, Philipp; Leist, Anja UL; Riumallo-Herl, Carlos J. et al

in http://paa2015.princeton.edu (2015)

Based on a linkage of state unemployment rates and individual-level data from the Health and Retirement Study (HRS), we assess whether exposure to unfavorable macroeconomic conditions in the years leading ... [more ▼]

Based on a linkage of state unemployment rates and individual-level data from the Health and Retirement Study (HRS), we assess whether exposure to unfavorable macroeconomic conditions in the years leading up to retirement affect both levels as well as changes in cognitive functioning after retirement. Our results suggest that recessions experienced in the years prior to retirement can have substantial negative effects on cognitive function at age 65 and beyond. Our results are robust to various specifications and suggest that these effects are particularly strong for older workers with unstable careers who are hit by a recession, while they are similar for individuals from different race or educational level. [less ▲]

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See detailDynamic and complex optical patterns from colloids of cholesteric liquid crystal droplets
Noh, Junghyun UL; Drevensek-Olenik, Irena; Yamamoto, Jun et al

in Proceedings of the SPIE (2015), 9384

Drops or shells of a planar-aligned short-pitch cholesteric liquid crystal exhibit unique optical properties due to the combination of Bragg reflection in the cholesteric helix and a radial orientation of ... [more ▼]

Drops or shells of a planar-aligned short-pitch cholesteric liquid crystal exhibit unique optical properties due to the combination of Bragg reflection in the cholesteric helix and a radial orientation of the helix axis. If such a droplet is illuminated from above, light is reflected into a continuous set of cones, the opening angles of which depend on where on the droplet the light hits its surface. For the wavelength that fulfills the Bragg condition the reflection is dramatically enhanced, yielding the light cones colored. A photonic cross communication scheme arises for certain angles, reflecting light back to the observer from a different droplet than the one originally illuminated. This gives rise to an intricate pattern of colored and circularly polarized spots. A number of interesting applications may be developed based on this pattern, e.g. in identification and authentication devices. We have carried out a detailed spectrophotometric analysis of the patterns, localized to individual spot maxima. A quantitative comparison between the measured spectra and the reflection wavelength expected from a model for the pattern generation allows us to conclude that the droplets are in fact not spherical but slightly ellipsoidal. [less ▲]

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See detailRelative breathless: Comparison with others can affect feelings of breathlessness.
Petersen, Sibylle UL; Van den Bergh, Omer

in Biological Psychology (2015), 104

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See detailTopological States in Multi-Orbital Honeycomb Lattices of HgTe (CdTe) Quantum Dots
Beugeling, Wouter; Kalesaki, Efterpi UL; Delerue, Christophe et al

in ECS Transactions (2015), 69(5), 81-88

We summarize recent theoretical works on artificial graphene realized by honeycomb lattices of semiconductor (CdSe, HgTe, CdTe) quantum dots forming a two-dimensional single-crystalline sheet. In the case ... [more ▼]

We summarize recent theoretical works on artificial graphene realized by honeycomb lattices of semiconductor (CdSe, HgTe, CdTe) quantum dots forming a two-dimensional single-crystalline sheet. In the case of CdSe, we predict conduction bands with Dirac cones at two distinct energies and nontrivial flat bands. An analogous behavior is found in HgTe but, in addition, the strong spin-orbit coupling opens large topologically nontrivial gaps, leaving a flattened band detached from the others. We deduce that honeycomb lattices of HgTe quantum dots may constitute promising platforms for the observation of a fractional Chern insulator or a fractional quantum spin Hall phase. Similar predictions are made for CdTe but with smaller nontrivial gaps. [less ▲]

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See detailPrediction of Photovoltaic Cu(In,Ga)Se2 p-n Device Performance by forward Bias Electrochemical Analysis of Only the p-Type Cu(In,Ga)Se2 Films
Colombara, Diego UL; Bertram, Tobias UL; Depredurand, Valérie UL et al

in Electrochemical Society Transactions (2015), 66(6), 19-25

This work is an attempt to rate the quality of Mo/Cu(In,Ga)Se2 films intended for fabrication of photovoltaic devices. The procedure is based on the simple current-voltage electrochemical analysis of the ... [more ▼]

This work is an attempt to rate the quality of Mo/Cu(In,Ga)Se2 films intended for fabrication of photovoltaic devices. The procedure is based on the simple current-voltage electrochemical analysis of the bilayer in a Eu2+/3+-containing electrolyte solution. Two series of bilayer samples were tested electrochemically, while sister samples were completed into Mo/Cu(In,Ga)Se2/CdS/i-ZnO/Al:ZnO/Ni-Al solid state devices and their current-voltage characteristics measured in the dark. A correlation was found between the reverse saturation current density of the solid state devices and an analogous parameter extracted from the electrochemical response in forward bias. While Eu2+ was found to be metastable in water posing restrictions to the application, reproducible measurements were achieved with a methanol-based solution. The intrinsic simplicity of the proposed methodology makes it particularly suitable for the implementation of a low-cost diagnostic tool. [less ▲]

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See detailTowards a full support of obligations in XACML
El Kateb, Donia UL; Elrakaiby, Y.; Mouelhi, T. et al

in Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (2015), 8924

Policy-based systems rely on the separation of concerns, by implementing independently a software system and its associated security policy. XACML (eXtensible Access Control Markup Language) proposes a ... [more ▼]

Policy-based systems rely on the separation of concerns, by implementing independently a software system and its associated security policy. XACML (eXtensible Access Control Markup Language) proposes a conceptual architecture and a policy language to reflect this ideal design of policy-based systems.However, while rights are well-captured by authorizations, duties, also called obligations, are not well managed by XACML architecture. The current version of XACML lacks (1) well-defined syntax to express obligations and (2) an unified model to handle decision making w.r.t. obligation states and the history of obligations fulfillment/ violation. In this work, we propose an extension of XACML reference model that integrates obligation states in the decision making process.We have extended XACML language and architecture for a better obligations support and have shown how obligations are managed in our proposed extended XACML architecture: OB-XACML. © Springer International Publishing Switzerland 2015. [less ▲]

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See detailHow can we promote cognitive reserve during the life course? Social, behavioral, contextual factors
Leist, Anja UL

in Gerontologist (2015), 55(Suppl 2), 210

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See detailWeight loss associated with socioeconomic status in patients with angina pectoris, 5 years after an angiography
Tchicaya, Anastase; Baumann, Michèle UL

in Cardiology (2015), (132 (suppl 1)), 60

The aim of the study is to assess the association between weight loss and socioeconomic status (SES) in patients with cardiovascular disease (CVD) such as angina pectoris. Method:In 2013-2014, 1,873 ... [more ▼]

The aim of the study is to assess the association between weight loss and socioeconomic status (SES) in patients with cardiovascular disease (CVD) such as angina pectoris. Method:In 2013-2014, 1,873 patients out of 4,391 that had undergone an angiography in 2008 -2009 participated in a follow-up study. Among these patients, 457 suffered from angina pectoris and were obese or overweight at baseline. A self-administered questionnaire was completed. Moderate weight loss was defined as the loss of 5%-10%, severe weigh loss as more than 10 % of baseline weight. Household-income was used as proxy for SES. Logistic regression was applied to assess the association between weight loss and SES. Results:During the reference period, 28% of the participants lost weight. A moderate weight loss was higher in patients with a household income between 3000€ and 4500€ per month (OR: 2.3; CI 95%: 1.0-5.2) and higher than 4500€ per month (OR: 3.0; CI 95%: 1.3-7.2) compared to the lowest income group (less than 3000€ per month). A severe weight loss was not associated with income. However, a severe weight loss was higher for retired patients (OR: 4.3; CI 95%: 1.1-17.0) compared to non-retired.Conclusion: The potential reduction of health inequality by an elimination of social inequalities in weight loss among patients with angina pectoris might be substantial. Moderate weight loss in overweight patients with angina pectoris at baseline could be associated with household income. Intervention strategies in secondary prevention should address these social inequalities in order to support equity in health. [less ▲]

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See detailL’influence des représentations du « public populaire » sur la conception d’une exposition d’archéologie
Schall, Céline UL; Vilatte, Jean-Christophe

in Questions de Communication (2015)

Lors du montage d’une exposition, un des éléments importants du projet est le choix du public auquel les professionnels des musées souhaitent s’adresser. De quelle(s) manière(s) l’objectif de toucher le « ... [more ▼]

Lors du montage d’une exposition, un des éléments importants du projet est le choix du public auquel les professionnels des musées souhaitent s’adresser. De quelle(s) manière(s) l’objectif de toucher le « public populaire » ou le « grand public » joue-t-il sur les procédures de concep-tion et de réalisation d’une exposition ? Pour répondre à cette question, nous analyserons le cas d’une exposition temporaire d’archéologie à travers le discours de ses concepteurs et son étude sémiotique. Si les représentations spontanées que les différents corps professionnels (scienti-fiques, médiateurs, scénographes) ont de ce « grand public » sont assez proches, elles divergent quand il s’agit d’écrire les textes ou de concevoir des dispositifs de médiation. La notion s’avère peu précise et en définitive peu opérante. Elle conduit les participants à avoir tendance à produire leurs propres stratégies muséographiques, au risque d’incohérences et d’un certain manque de lisibilité. [less ▲]

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See detailStudents’ Well-being: Impacts of studying out-EU and perceived autonomy on the Psychological Quality of Life
Bucki, Barbara UL; Karavdic, Senad UL; Karathanasi, Chrysoula UL et al

in European Health Psychologist (The) (2015), special

Introduction: With an increasing number of university students in preparation of their entrance in the labor market, the wellbeing of the postgraduates became a priority for many universities. Despite ... [more ▼]

Introduction: With an increasing number of university students in preparation of their entrance in the labor market, the wellbeing of the postgraduates became a priority for many universities. Despite numerous studies on this topic, respective relationships of wellbeing and other psychosocial factors still remain unclear. Aims: (1) to assess Psychological Quality of Life of postgraduates who study in Grand Duchy of Luxembourg (GDL), EU and non – EU countries; (2) to analyze its associations with their socio-economic,health and employability related cofactors. Method: All masters’ students registered at the Centre for Documentation and Information on Higher Education (CEDIES) database in GDL were contacted by mail to participate at an online questionnaire (in English or French) measuring: 1. Psychological Whoqol-bref (6 items) (dependent variable) 2. Wellbeing attributes: Quality of Life Autonomy, Health Satisfaction, and Penn state worry questionnaire (Worries). 3. Employability attributes: Search for Work Self Efficacy scale (SWSES), Career Goals setting. 4. Perceived financial situation and socio-demographic characteristics. Respondents who did not mention the country of their studies were excluded from the analysis. Bivariate tests and correlations were performed for association analyses between the variables. Only significant relationships (p<0.05) were used in the multiple linear model. Results: 490 participants were volunteers from which 13.5% study in Luxembourg, 77.8% in an EU country and 8.7% in a non EU country. Majority were women, with exception for those studying in non-EU countries who were mainly men. Participants studying in GDL were older than those studying abroad. Natives of Luxembourg were prevalent with higher percentages among those who study in a non EU-country. Those studying in non-EU showed significantly (p<0.05) higher Psychological Quality of Life (M=76.8; SD=12.8) than those in GDL (M=74.5;SD=12.6) respectively in EU (M=71.4; SD=15.3). While participants differ in their QoL-Autonomy score there isn’t any significant difference in their career goals setting, Search for work self efficacy, Health satisfaction, Worries and Perceived financial situation across the country of study.Conclusion: Better psychological quality of life mobilized the capability of students to study abroad, which is related to better wellbeing attributes. However this relationship remains true only for students studying in Non-EU countries. Implementing workshops to increase individual self-efficacy towards a future employment may improve and/or maintain wellbeing of academics and limit so, respective social inequalities. [less ▲]

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See detailWhy medication or tobacco consumption enhance the life satisfaction of cardiovascular patients?
Bucki, Barbara UL; Tchicaya, Anastase; Baumann, Michèle UL

in European Health Psychologist (The) (2015), special

While life satisfaction (LS) promotes the health of cardiovascular patients, LS may be affected by a range of primary and secondary determinants. We analysed LS and its relationships with cardiovascular ... [more ▼]

While life satisfaction (LS) promotes the health of cardiovascular patients, LS may be affected by a range of primary and secondary determinants. We analysed LS and its relationships with cardiovascular risk factors and unhealthy behaviours. Methods. In 2013, 3,632 survivors who underwent coronary angiography in 2008-2009 at the Luxembourgish National Institute of Cardiac Surgery and Cardiological Intervention (INCCI), living at home were asked to estimate, five years after, their LS [1-10] and other health-related variables. Data were analysed via multiple regression models including interaction effects. Findings. LS of the 1,289 participants (age: 69.2±11.1) was 7.3/10. Most were men, employees or manual workers, had secondary education and a 36,000€ or more/year income. The interactions between hypercholesterolemia and hypertension (regression coefficient= 0.628) and with smoking (rc= 0.941) were positively related with LS, but physical inactivity was negatively associated (rc= -0.630). Discussion. Taking medications or maintaining tobacco consumption produces better LS than being ambivalent towards physical activity. Further research is needed to evaluate the efficacy of health interventions eliciting and promoting the behaviour change wheel based on capabilities, opportunities, and motivations. [less ▲]

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See detailUpward social mobility and life satisfaction: the cases of United Kingdom and Switzerland
Samuel, Robin UL; Hadjar, Andreas UL

in Longitudinal and Life Course Studies (2015), 6(3), 13-14

Status is a major determinant of subjective well-being (SWB). This is one of the primary assumptions of social production function theory. In contrast, the dissociative hypothesis holds that upward social ... [more ▼]

Status is a major determinant of subjective well-being (SWB). This is one of the primary assumptions of social production function theory. In contrast, the dissociative hypothesis holds that upward social mobility may be linked to identity problems, cognitive distress, and reduced levels of SWB because of lost ties to one’s class of origin. In our paper, we use panel data from the United Kingdom (British Household Panel Survey) and Switzerland (Swiss Household Panel) to test these hypotheses. These two countries are compared because historically, social inequality and upward mobility have played distinct roles in each country’s popular discourse. We conduct longitudinal multilevel analyses to gauge the effects of intragenerational and intergenerational upward mobility on life satisfaction (as a cognitive component of SWB), controlling for previous levels of life satisfaction, dynamic class membership, and well-researched determinants of SWB such as age and health problems. Our results provide some evidence for effects of social class and social mobility on well-being in the UK sample, however, there are no such effects in the Swiss sample. The UK findings support the idea of dissociative effects, that is, intergenerational upward mobility is negatively associated with SWB. [less ▲]

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See detailResource allocation for cognitive satellite uplink and fixed-service terrestrial coexistence in ka-band
Lagunas, E.; Sharma, Shree Krishna UL; Maleki, Sina UL et al

in Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST (2015), 156

This paper addresses the cognitive Geostationary Orbit (GSO) satellite uplink where satellite terminals reuse frequency bands of Fixed-Service (FS) terrestrial microwave links which are the incumbent ... [more ▼]

This paper addresses the cognitive Geostationary Orbit (GSO) satellite uplink where satellite terminals reuse frequency bands of Fixed-Service (FS) terrestrial microwave links which are the incumbent users in the Ka 27.5-29.5 GHz band. In the scenario considered herein, the transmitted power of the cognitive satellite user has to ensure that the interference impact on potentially present FS links does not exceed the regulatory interference limitations. In order to satisfy the interference constraint and assuming the existence of a complete and reliable FS database, this paper proposes a Joint Power and Carrier Allocation (JPCA) strategy to enable the cognitive uplink access to GSO Fixed Satellite Service (FSS) terminals. The proposed approach identifies the worst FS link per user in terms of interference and divides the amount of tolerable interference among the maximum number of FSS terminal users that can potentially interfere with it. In so doing, the cognitive system is guaranteed to never exceed the prescribed interference threshold. Subsequently, powers and carriers are jointly allocated so as to maximize the throughput of the FSS system. Supporting results based on numerical simulations are provided. It is shown that the proposed cognitive approach represents a promising solution to significantly boost the performance of conventional satellite systems. © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2015. [less ▲]

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