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See detailHomotopical algebraic context over differential operators
Di Brino, Gennaro; Pistalo, Damjan UL; Poncin, Norbert UL

in Journal of Homotopy and Related Structures (in press)

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See detailRevisiting Gaussian Mixture Models for Driver Identification
Jafarnejad, Sasan UL; Castignani, German UL; Engel, Thomas UL

in Proceedings of IEEE International Conference on Vehicular Electronics and Safety (ICVES) (ICVES 2018) (in press)

The increasing penetration of connected vehicles nowadays has enabled driving data collection at a very large scale. Many telematics applications have been also enabled from the analysis of those datasets ... [more ▼]

The increasing penetration of connected vehicles nowadays has enabled driving data collection at a very large scale. Many telematics applications have been also enabled from the analysis of those datasets and the usage of Machine Learning techniques, including driving behavior analysis predictive maintenance of vehicles, modeling of vehicle health and vehicle component usage, among others. In particular, being able to identify the individual behind the steering wheel has many application fields. In the insurance or car-rental market, the fact that more than one driver make use of the vehicle generally triggers extra fees for the contract holder. Moreover being able to identify different drivers enables the automation of comfort settings or personalization of advanced driver assistance (ADAS) technologies. In this paper, we propose a driver identification algorithm based on Gaussian Mixture Models (GMM). We show that only using features extracted from the gas pedal position and steering wheel angle signals we are able to achieve near 100 accuracy in scenarios with up to 67 drivers. In comparison to the state-of-the-art, our proposed methodology has lower complexity, superior accuracy and offers scalability to a larger number of drivers. [less ▲]

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See detailAn Empirical Evaluation of Evolutionary Algorithms for Unit Test Suite Generation
Campos, Jose; Ge, Yan; Albunian, Nasser et al

in Information and Software Technology (in press)

Context: Evolutionary algorithms have been shown to be e ective at generating unit test suites optimised for code coverage. While many speci c aspects of these algorithms have been evaluated in detail (e ... [more ▼]

Context: Evolutionary algorithms have been shown to be e ective at generating unit test suites optimised for code coverage. While many speci c aspects of these algorithms have been evaluated in detail (e.g., test length and di erent kinds of techniques aimed at improving performance, like seeding), the in uence of the choice of evolutionary algorithm has to date seen less attention in the literature. Objective: Since it is theoretically impossible to design an algorithm that is the best on all possible problems, a common approach in software engineering problems is to rst try the most common algorithm, a Genetic Algorithm, and only afterwards try to re ne it or compare it with other algorithms to see if any of them is more suited for the addressed problem. The objective of this paper is to perform this analysis, in order to shed light on the in uence of the search algorithm applied for unit test generation. Method: We empirically evaluate thirteen di erent evolutionary algorithms and two random approaches on a selection of non-trivial open source classes. All algorithms are implemented in the EvoSuite test generation tool, which includes recent optimisations such as the use of an archive during the search and optimisation for multiple coverage criteria. Results: Our study shows that the use of a test archive makes evolutionary algorithms clearly better than random testing, and it con rms that the DynaMOSA many-objective search algorithm is the most e ective algorithm for unit test generation. Conclusions: Our results show that the choice of algorithm can have a substantial in uence on the performance of whole test suite optimisation. Although we can make a recommendation on which algorithm to use in practice, no algorithm is clearly superior in all cases, suggesting future work on improved search algorithms for unit test generation [less ▲]

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See detailIdentifying elastoplastic parameters with Bayes' theorem considering double error sources and model uncertainty
Rappel, Hussein UL; Beex, Lars UL; Noels, Ludovic et al

in Probabilistic Engineering Mechanics (in press)

We discuss Bayesian inference for the identi cation of elastoplastic material parameters. In addition to errors in the stress measurements, which are commonly considered, we furthermore consider errors in ... [more ▼]

We discuss Bayesian inference for the identi cation of elastoplastic material parameters. In addition to errors in the stress measurements, which are commonly considered, we furthermore consider errors in the strain measurements. Since a difference between the model and the experimental data may still be present if the data is not contaminated by noise, we also incorporate the possible error of the model itself. The three formulations to describe model uncertainty in this contribution are: (1) a random variable which is taken from a normal distribution with constant parameters, (2) a random variable which is taken from a normal distribution with an input-dependent mean, and (3) a Gaussian random process with a stationary covariance function. Our results show that incorporating model uncertainty often, but not always, improves the results. If the error in the strain is considered as well, the results improve even more. [less ▲]

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See detailTeacher expectations concerning students with immigrant background or special educational needs
Pit-Ten Cate, Ineke UL; Glock, Sabine UL

in Journal of Educational Research and Evaluation (in press)

Male students with immigrant backgrounds are disproportionally referred for special educational support outside regular classrooms or schools, which may reflect differential teachers´ expectations ... [more ▼]

Male students with immigrant backgrounds are disproportionally referred for special educational support outside regular classrooms or schools, which may reflect differential teachers´ expectations concerning the academic achievement of students based on socio-demographic characteristics. Although research has indicated differential teachers´ expectations for students based on immigrant background or special educational needs (SEN), less is known about a possible double vulnerability associated with combined stereotypes. Therefore, in the current study both SEN and immigrant background were systematically varied and teachers were asked to rate the students´ academic achievement. Results show that teachers´ expectations of students with SEN and immigrant background was lower than for students without immigrant background, especially in regards to language proficiency. These results may help to explain the overrepresentation of students with immigrant background in special educational programs. The educational and theoretical implications of these findings are discussed. [less ▲]

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

in Transportation Science (in press)

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See detailNew synthetic opioids: Part of a new addiction landscape.
Karila, Laurent; Marillier, Maude; Chaumette, Boris et al

in Neuroscience and biobehavioral reviews (in press)

Synthetic opioids (SO) are a major risk for public health across the world. These drugs can be divided into 2 categories, pharmaceutical and non-pharmaceutical fentanyls. A new generation of SO has ... [more ▼]

Synthetic opioids (SO) are a major risk for public health across the world. These drugs can be divided into 2 categories, pharmaceutical and non-pharmaceutical fentanyls. A new generation of SO has emerged on the drug market since 2010. North America is currently facing an opioid epidemic of morbi-mortality, caused by over-prescription of opioids, illegally diverted prescribed medicines, the increasing use of heroin, is and the emergence of SO. Furthermore, this opioid crisis is also seen in Europe. SO are new psychoactive substances characterized by different feature such as easy availability on the Internet, low price, purity, legality, and lack of detection in laboratory tests. They have not been approved or are not recommended for human use. Opioid misuse is associated with somatic and psychiatric complications. For many substances, limited pharmacological information is available, increasing the risk of harmful adverse events. Health actors and the general population need to be clearly informed of the potential risks and consequences of the diffusion and use of SO. [less ▲]

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See detailImpact of GPS Antenna Phase Center Models on Zenith Wet Delay and Tropospheric Gradients
Ejigu, Yohannes Getachew; Hunegnaw, Addisu UL; Abraha, Kibrom Ebuy UL et al

in GPS Solutions (in press)

We demonstrate the potential for the Global Positioning System (GPS) to provide highly accurate tropospheric products for use in meteorological applications. Tropospheric products, in particular the wet ... [more ▼]

We demonstrate the potential for the Global Positioning System (GPS) to provide highly accurate tropospheric products for use in meteorological applications. Tropospheric products, in particular the wet delays, are treated as an unknown parameter in GPS processing and are estimated with other parameters such as station coordinates. In this study, we investigate the effects of Phase Center Correction (PCC) models on tropospheric zenith wet delay (ZWD), integrated water vapor (IWV) and gradient products. Two solutions were generated using the GAMIT software over the EUREF Permanent GNSS Network (EPN). The first (reference) solution was derived by applying the International GNSS Service (IGS) type-mean PCC model, while for the second solution PCC models from individual calibrations were used. The solutions were generated identically, except for the PCC model differences. The two solutions were compared, with the assumption that common signals are differenced out. The comparison of the two solutions clearly shows a bias in all tropospheric products, which can be attributed to PCC model deficiencies. Overall, mean biases of ±1.8, ±0.3, ±0.14 and ±0.19 mm are evident in ZWD, IWV, North-South and East-West gradients, respectively. Moreover, the differences between the two solutions show seasonal variations. For all antenna types, the ZWD and IWV differences are dominated by white plus power-law noise, with latter characterizing the low-frequency spectrum. On the other hand, the horizontal gradients exhibit a white plus first order autoregressive noise characteristic with less than 1% white noise. The individual PCC model provides a better fit to an external independent model in terms of gradient estimate and also provides up to 3 % more carrier phase ambiguity resolution. [less ▲]

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See detailAssessing binge-watching behaviors: Development and validation of the “Watching TV Series Motives” and “Binge-Watching Engagement and Symptoms” questionnaires
Flayelle, Maèva UL; Canale, Natale; Vögele, Claus UL et al

in Computers in Human Behavior (2019), 90

The widespread practice of binge-watching (i.e. watching multiple episodes of a TV series in one session) recently generated concerns about associated negative outcomes. Its psychological investigation ... [more ▼]

The widespread practice of binge-watching (i.e. watching multiple episodes of a TV series in one session) recently generated concerns about associated negative outcomes. Its psychological investigation, however, remains fragmentary. Based on the previous phenomenological investigation of TV series watching, we developed and validated two original assessment instruments, assessing TV series watching motives and binge-watching engagement and symptoms, respectively. Preliminary items were created for each questionnaire, and a focus group with TV series viewers was conducted and analyzed to generate the final instruments. The questionnaires were then administered via an online survey (N=6556), together with complementary measures of affect, problematic Internet use and substance use. Exploratory and confirmatory factor analyses, along with correlational analyses, were performed to examine both structural and external validity of the scales. The factorial analyses resulted in a 4-factor model (i.e. emotional enhancement, enrichment, coping-escapism and social) for the Watching TV Series Motives Questionnaire (WTSMQ), and in a 7-factor model (i.e. engagement, positive emotions, desire-savoring, pleasure preservation, binge-watching, dependency and loss of control) for the Binge-Watching Engagement and Symptoms Questionnaire (BWESQ). The results suggest good psychometric properties for both scales. The current study thus provides theoretically-driven and psychometrically sound instruments for further research on binge-watching behaviors [less ▲]

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See detailStriking a balance between competitiveness and social fairness: what can we expect from the European Pillar of Social Rights?
Muñoz, Susana UL

in Chiocchetti, Paolo; Allemand, Frédéric (Eds.) Competitiveness and Solidarity in the European Union: Interdisciplinary Perspectives (2019)

The solemnly proclaimed European Pillar of Social Rights provides a meaningful response to the process of building a deeper, fairer European Union in the aftermath of the crisis. This chapter aims to ... [more ▼]

The solemnly proclaimed European Pillar of Social Rights provides a meaningful response to the process of building a deeper, fairer European Union in the aftermath of the crisis. This chapter aims to provide a critical assessment of the nature, scope, rationale, purpose, content and effectiveness of the Pillar in the light of its potential contribution to foster social fairness and competitiveness in the EU. The Pillar complements and develops the EU’s social acquis and reinforces standards which may provide a fairer and more socially-balanced competitiveness in the EU. Progress has been made, but further efforts are needed to build a sense of common purpose to strengthen the social foundations of the Union. [less ▲]

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See detailA Pedagogical Note on Risk Sharing Versus Instability in International Financial Integration: When Obstfeld Meets Stiglitz
Boucekkine, Raouf; Zou, Benteng UL

in Open Economies Review (2019)

The pure risk sharing mechanism implies that financial liberalization is growth enhancing for all countries as the world portfolio shifts from safe low-yield capital to riskier high-yield capital. This ... [more ▼]

The pure risk sharing mechanism implies that financial liberalization is growth enhancing for all countries as the world portfolio shifts from safe low-yield capital to riskier high-yield capital. This result is typically obtained under the assumption that the volatilities for risky assets prevailing under autarky are not altered after liberalization. We relax this assumption within a simple two-country model of intertemporal portfolio choices. By doing so, we put together the risk sharing effect and a well defined instability effect. We identify the conditions under which liberalization may cause a drop in growth. These conditions combine the typical threshold conditions outlined in the literature, which concern the deep characteristics of the economies, and size conditions on the instability effect induced by liberalization. [less ▲]

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See detailClimate politics: how public persuasion affects the trade-off between environmental and economic performance
Prieur, Fabien; Zou, Benteng UL

in Mathematical Social Sciences (2019)

This paper aims at studying the impact of public persuasion, through information dissemination, on environmental and economic performance. A differential game in which opposite interest groups compete for ... [more ▼]

This paper aims at studying the impact of public persuasion, through information dissemination, on environmental and economic performance. A differential game in which opposite interest groups compete for bringing the majority’s environmental concern closer to their views is developed. The results show a strong asymmetry in the impact of public persuasion. It may bring the median voter economy closer to the social optimum in the long run, thereby reducing environmental and economic distorsions. But this only occurs when the environmental group exhibits a radical ideology and people are initially closer to the industrialists’ views. By contrast, economies where industrial groups are powerful and strongly opposed to environmental protection never benefit from the outcome of the game of persuasion. This may explain why the US have failed to take action on global warming up to now. [less ▲]

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See detailTo MigrateWith orWithout Ones’ Children in China - That is the Question
Chen, Yiwen UL; Fromentin, Vincent; Zou, Benteng UL

in Annals of Eceonomcis and statistics (2019)

Where should Chinese internal migrant parents locate their school-aged children: migrate with them or leave them behind? And should they invest in private education of their children? We investigate ... [more ▼]

Where should Chinese internal migrant parents locate their school-aged children: migrate with them or leave them behind? And should they invest in private education of their children? We investigate whether migrant parents can afford to take their children to migrate and thus provide theoretical optimum that maximizes migrant parents’ utility which includes the children’s educational performance. Depending on the educational investment parents make and the relocation cost of children, we provide necessary and sufficient conditions under which migrant parents should take their children to migrate and conditions under which migrant parents should provide their children with private education. [less ▲]

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See detailJewish responses to anti-Semitism in Paris and London in the late 1930s as European Jewish political history
Zaagsma, Gerben UL

in Bajohr, Frank; Löw, Andrea; Wirsching, Andreas (Eds.) Right-Wing Politics and the Rise of Antisemitism in Europe 1935-1941 (2018)

This article compares Jewish responses to antisemitism in Paris and London in the late 1930s, when antisemitism was on the rise in both France and the United Kingdom. There were striking similarities in ... [more ▼]

This article compares Jewish responses to antisemitism in Paris and London in the late 1930s, when antisemitism was on the rise in both France and the United Kingdom. There were striking similarities in these responses, yet local contexts and circumstances dominate the historiographies of both cases. The main aim of this article, then, is not so much to offer new insights into the individual cases (both of which have been abundantly analyzed in historical research), but rather to fill a gap by examining the broader factors that account for these similarities. On the one hand, the article examines the nature of Jewish self-identification in the post-Emancipation era and its effects on the political cultures, practices, and identifications of the actors that were involved; on the other, it explores the way in which these practices were also shaped by migration and transnational aspects. Ultimately, this case study will argue for a comparative and transnational approach to Jewish political history in order to arrive at a better understanding of its diverse configurations and permutations. [less ▲]

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See detailOsiris: Hunting for Integer Bugs in Ethereum Smart Contracts
Ferreira Torres, Christof UL; Schütte, Julian; State, Radu UL

in 34th Annual Computer Security Applications Conference (ACSAC ’18), San Juan, Puerto Rico, USA, December 3-7, 2018 (2018, December)

The capability of executing so-called smart contracts in a decentralised manner is one of the compelling features of modern blockchains. Smart contracts are fully fledged programs which cannot be changed ... [more ▼]

The capability of executing so-called smart contracts in a decentralised manner is one of the compelling features of modern blockchains. Smart contracts are fully fledged programs which cannot be changed once deployed to the blockchain. They typically implement the business logic of distributed apps and carry billions of dollars worth of coins. In that respect, it is imperative that smart contracts are correct and have no vulnerabilities or bugs. However, research has identified different classes of vulnerabilities in smart contracts, some of which led to prominent multi-million dollar fraud cases. In this paper we focus on vulnerabilities related to integer bugs, a class of bugs that is particularly difficult to avoid due to some characteristics of the Ethereum Virtual Machine and the Solidity programming language. In this paper we introduce Osiris – a framework that combines symbolic execution and taint analysis, in order to accurately find integer bugs in Ethereum smart contracts. Osiris detects a greater range of bugs than existing tools, while providing a better specificity of its detection. We have evaluated its performance on a large experimental dataset containing more than 1.2 million smart contracts. We found that 42,108 contracts contain integer bugs. Be- sides being able to identify several vulnerabilities that have been reported in the past few months, we were also able to identify a yet unknown critical vulnerability in a couple of smart contracts that are currently deployed on the Ethereum blockchain. [less ▲]

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See detailSequential Resource Distribution Technique for Multi-User OFDM-SWIPT based Cooperative Networks
Gautam, Sumit UL; Lagunas, Eva UL; Chatzinotas, Symeon UL et al

Scientific Conference (2018, December)

In this paper, we investigate resource allocation and relay selection in a dual-hop orthogonal frequency division multiplexing (OFDM)-based multi-user network where amplify-and-forward (AF) enabled relays ... [more ▼]

In this paper, we investigate resource allocation and relay selection in a dual-hop orthogonal frequency division multiplexing (OFDM)-based multi-user network where amplify-and-forward (AF) enabled relays facilitate simultaneous wireless information and power transfer (SWIPT) to the end-users. In this context, we address an optimization problem to maximize the end-users’ sum-rate subjected to transmit power and harvested energy constraints. Furthermore, the problem is formulated for both time-switching (TS) and power-splitting (PS) SWIPT schemes.We aim at optimizing the users’ SWIPT splitting factors as well as sub-carrier–destination assignment, sub-carrier pairing, and relay–destination coupling metrics. This kind of joint evaluation is combinatorial in nature with non-linear structure involving mixed-integer programming. In this vein, we propose a sub-optimal low complex sequential resource distribution (SRD) method to solve the aforementioned problem. The performance of the proposed SRD technique is compared with a semi-random resource allocation and relay selection approach. Simulation results reveal the benefits of the proposed design under several parameter values with various operating conditions to illustrate the efficiency of SWIPT schemes for the proposed techniques. [less ▲]

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See detailPower and Load Optimization in Interference-Coupled Non-Orthogonal Multiple Access Networks
Lei, Lei UL; You, Lei; Yang, Yang UL et al

in IEEE Global Communications Conference (GLOBECOM) 2018 (2018, December)

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See detailCollaborative Data Delivery for Smart City-oriented Mobile Crowdsensing Systems
Vitello, Piergiorgio; Capponi, Andrea UL; Fiandrino, Claudio UL et al

in IEEE Global Communications Conference (GLOBECOM), Abu Dhabi, UAE, 2018 (2018, December)

The huge increase of population living in cities calls for a sustainable urban development. Mobile crowdsensing (MCS) leverages participation of active citizens to improve performance of existing sensing ... [more ▼]

The huge increase of population living in cities calls for a sustainable urban development. Mobile crowdsensing (MCS) leverages participation of active citizens to improve performance of existing sensing infrastructures. In typical MCS systems, sensing tasks are allocated and reported on individual-basis. In this paper, we investigate on collaboration among users for data delivery as it brings a number of benefits for both users and sensing campaign organizers and leads to better coordination and use of resources. By taking advantage from proximity, users can employ device-to-device (D2D) communications like Wi-Fi Direct that are more energy efficient than 3G/4G technology. In such scenario, once a group is set, one of its member is elected to be the owner and perform data forwarding to the collector. The efficiency of forming groups and electing suitable owners defines the efficiency of the whole collaborative-based system. This paper proposes three policies optimized for MCS that are compliant with current Android implementation of Wi-Fi Direct. The evaluation results, obtained using CrowdSenSim simulator, demonstrate that collaborative-based approaches outperform significantly individual-based approaches. [less ▲]

Detailed reference viewed: 29 (2 UL)
See detailResearching education in Luxembourg (symposium)
Fischbach, Antoine UL

Scientific Conference (2018, November 08)

Detailed reference viewed: 4 (2 UL)