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See detailMères à temps partiel, fratries à temps complet
Haxhe, Stéphanie ULiege

Conference given outside the academic context (2017)

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See detailL'enfant parentifié, lorsque les rôles s'inversent dans la famille
Haxhe, Stéphanie ULiege

Conference given outside the academic context (2017)

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See detailDetermining the metallicity of the solar envelope using seismic inversion techniques
Buldgen, Gaël ULiege; Salmon, Sébastien ULiege; Noels-Grötsch, Arlette ULiege et al

in Monthly Notices of the Royal Astronomical Society (2017), 472(1), 751-764

The solar metallicity issue is a long-lasting problem of astrophysics, impacting multi- ple fields and still subject to debate and uncertainties. While spectroscopy has mostly been used to determine the ... [more ▼]

The solar metallicity issue is a long-lasting problem of astrophysics, impacting multi- ple fields and still subject to debate and uncertainties. While spectroscopy has mostly been used to determine the solar heavy elements abundance, helioseismologists at- tempted providing a seismic determination of the metallicity in the solar convective enveloppe. However, the puzzle remains since two independent groups prodived two radically different values for this crucial astrophysical parameter. We aim at provid- ing an independent seismic measurement of the solar metallicity in the convective enveloppe. Our main goal is to help provide new information to break the current stalemate amongst seismic determinations of the solar heavy element abundance. We start by presenting the kernels, the inversion technique and the target function of the inversion we have developed. We then test our approach in multiple hare-and-hounds exercises to assess its reliability and accuracy. We then apply our technique to solar data using calibrated solar models and determine an interval of seismic measurements for the solar metallicity. We show that our inversion can indeed be used to estimate the solar metallicity thanks to our hare-and-hounds exercises. However, we also show that further dependencies in the physical ingredients of solar models lead to a low accuracy. Nevertheless, using various physical ingredients for our solar models, we determine metallicity values between 0.008 and 0.014. [less ▲]

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See detailInversions of the Ledoux discriminant: a closer look at the tachocline
Buldgen, Gaël ULiege; Salmon, Sébastien ULiege; Godart, Mélanie ULiege et al

in Monthly Notices of the Royal Astronomical Society : Letters (2017), 472(1), 70-74

Modelling the base of the solar convective envelope is a tedious problem. Since the first rotation inversions, solar modellers are confronted with the fact that a region of very limited extent has an ... [more ▼]

Modelling the base of the solar convective envelope is a tedious problem. Since the first rotation inversions, solar modellers are confronted with the fact that a region of very limited extent has an enormous physical impact on the Sun. Indeed, it is the transition region from differential to solid body rotation, the tachocline, which furthermore is influenced by turbulence and is also supposed to be the seat of the solar magnetic dynamo. Moreover, solar models show significant disagreement with the sound speed profile in this region. In this paper, we show how helioseismology can provide further constraints on this region by carrying out an inversion of the Ledoux discriminant. We compare these inversions for Standard Solar Models built using various opacity tables and chemical abundances and discuss the origins of the discrepancies between Solar Models and the Sun. [less ▲]

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See detailAn agent-based framework for modeling travel behavior under disrupted networks
Saadi, Ismaïl ULiege

Doctoral thesis (2017)

Worldwide, floods are the most frequent natural disasters and cause over one third of overall economic losses due to natural hazards. In addition, studies show that flood risk will further increase during ... [more ▼]

Worldwide, floods are the most frequent natural disasters and cause over one third of overall economic losses due to natural hazards. In addition, studies show that flood risk will further increase during the 21st century as a result of climate change. In this context, the objective of this thesis is to implement a methodological framework for modeling the impact of disrupted networks caused by river floods on travel demand. The manuscript is divided into four chapters. In the first chapter, this thesis contributes to the state-of-the-art by presenting an integrated multidisciplinary framework capable of making long-term projections (time horizon 2050 and 2100) with the objective of mitigating future flood risk. Various aspects of modeling are discussed with a focus on the interactions between the different model components. The second chapter is dedicated to multi-source data fusion in transportation research. Indeed, conducting large scale data collection is difficult and requires substantial financial resources. In practice, micro-samples with small sampling rates are generally used for synthesizing populations of households and individuals. Unfortunately, they present important limitations from a qualitative point of view, i.e. lack of representativeness. In this regard, a full population synthesis procedure based on Hidden Markov Model (HMM) has been designed to enable multi-source data fusion and incorporate more heterogeneity into eventual poor data-sets. Our research revealed that HMM outperforms IPF for all the sampling rates smaller than 25% regardless the scalability, while the amount of input data used by HMM is lower compared with IPF. The characterization of activity-travel patterns is described in the third chapter. Indeed, to enable a better understanding of travel behavior, a simulation-based approach for population synthesis has been coupled with a profile Hidden Markov Model (pHMM) in laying the foundation for an innovative activity-based model. There have been several key issues that deserved special attention, in particular the influence of socio-demographics on the activity-travel patterns. We also proposed new perspectives of validation techniques. The simulated and observed activity-travel patterns have been systematically compared on the basis of the emission and transition probabilities. The fourth chapter is dedicated to the case study. The synthesized population is used to calibrate a large scale scenario based on the agent-based framework MATSim to investigate the short-term impact of river floods on travel demand. The model has been tested for Liège, Belgium with multiple flood risk scenarios. Results reveal that the impact in terms of travel times is particularly significant when the network is operating at capacities lower than 50%. [less ▲]

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See detailÉléments de méthodologie de la recherche documentaire en droit fiscal
Desseilles, François ULiege

Learning material (2017)

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See detailComment peut-on (encore) être persan ?
Jacquemain, Marc ULiege

Article for general public (2017)

L'article esquisse brièvement l'argument que lorsque le discours public oppose "nos valeurs" (celles des sociétés occidentales) aux "valeurs" musulmanes, ce discours, le plus souvent "distord" ou "réécrit ... [more ▼]

L'article esquisse brièvement l'argument que lorsque le discours public oppose "nos valeurs" (celles des sociétés occidentales) aux "valeurs" musulmanes, ce discours, le plus souvent "distord" ou "réécrit" nos propres valeurs pour les rendre difficilement inaccessibles aux musulmans. On prend trois exemples : l'enseignement de l'évolution, la mixité dans l'espace public, le choix d'un médecin en fonction de son sexe. On montre brièvement que sur ces trois questions, le discours public déforme ce qui constitue historiquement les "valeurs de nos sociétés" dans un but de stigmatisation de la minorité musulmane. [less ▲]

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See detailValidation of SAFIR through DIN EN 1992-1-2 NA: Comparison of the results for the examples presented in Annex CC
Romeiro Ferreira, Joao Daniel ULiege; Franssen, Jean-Marc ULiege; Gernay, Thomas ULiege et al

Report (2017)

Annex CC of DIN EN 1992-1-2 NA presents a series of cases that allow benchmarking software tools aimed at the design of structures in a fire situation. With the goal of providing a validation document for ... [more ▼]

Annex CC of DIN EN 1992-1-2 NA presents a series of cases that allow benchmarking software tools aimed at the design of structures in a fire situation. With the goal of providing a validation document for the finite element code SAFIR [1], a comparison of the reference results for the cases presented in the Annex CC with the results obtained by SAFIR has been carried out and is presented in this document. The validation typically consists in a comparison between the value of a result (temperature, displacement or others) obtained by SAFIR and the value given as a reference and supposed to be the « true » result. The value obtained must fall in the interval stipulated by the document. [less ▲]

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See detailBIGMOMAL - Big Data Analytics for Mobile Malware Detection
Wassermann, Sarah ULiege; Casas, Pedro

Poster (2017, November)

Mobile malware is on the rise. Due to their popularity, smartphones represent an attractive target for cybercriminals, especially regarding unauthorized access to private user data; smartphones ... [more ▼]

Mobile malware is on the rise. Due to their popularity, smartphones represent an attractive target for cybercriminals, especially regarding unauthorized access to private user data; smartphones incorporate a lot of sensitive information about users, even more than a personal computer. Indeed, besides personal information such as documents, accounts, passwords, contacts, etc., smartphone sensors centralize other sensitive data such as user location, physical activities, etc. In this paper, we study the problem of malware detection in smartphones, using supervised machine learning models and big data analytics frameworks. Using a publicly available dataset for smartphone data analysis (the SherLock data collection, see http://bigdata.ise.bgu.ac.il/sherlock/), we train and benchmark different supervised machine learning models to detect malware apps activity.The Sherlock data collection is a crowdsourcing-based smartphone dataset in which hundreds of features from many different "sensors" or vantage points within the device are monitored, using a tailored smartphone agent. The collection is done during a long-term - 2 years (2015/16), field trial on 50 smartphones used as primary device for 50 different participants. The monitoring agent collects a wide variety of network, software and sensor data at a high sample rate (as low as 5 seconds); in addition, participant devices include a sandbox-like smartphone agent which runs controlled malware apps, perpetrating attacks on the user's device (such as contacts theft, spyware, phishing, etc.), while creating labels for the SherLock dataset. The complete labeled dataset contains more than 10 billion data records, with a total of about 4 TB of data. We additionally complement the labels for malicious apps which might have been installed by participants by analyzing the installed apps' hashes in Virus Total (https://www.virustotal.com), a well-known multi antivirus online scanning system. From the complete dataset, we keep two specific feature categories: all those features related to the network traffic generated by the apps, and all those features corresponding to the footprint of the app on the CPU and internal running processes (e.g., statistics on CPUs, memory usage, linux-level processes information, etc.). The rationale is that some malware activity would be more visible at the network traffic level, whereas some others would be better identified at the local processes level. Using this dataset, we train different machine learning models (e.g., decision trees, neural networks, SVMs, etc.) and verify their accuracy to automatically spot out malicious apps running on the users’ devices. We also apply feature selection strategies to improve results and reduce computational times. Given the size of the dataset, we rely on big data platforms (such as Spark) to perform the analysis, complementing the machine learning based analysis with scikit-learn like pipelines. We evaluate three different concepts, including (i) overall model performance (using multi-fold cross validation on the complete dataset), (ii) generalization of the learned models across different users (train in N-1 users, and test in the remaining user), and (iii) detection accuracy drift along time (train during first month/week, test the resulting model in the subsequent months/weeks). Initial results are very promising, especially regarding overall model performance for decision tree based models. [less ▲]

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See detailAnycast on the Move - A First Look at Mobile Anycast Performance
Wassermann, Sarah ULiege; Rula, John P.; Bustamante, Fabian

Poster (2017, November)

Service providers rely on replication to improve service performance and reliability, placing instances in multiple locations and redirecting clients to nearby copies. Anycast is a common mechanism used ... [more ▼]

Service providers rely on replication to improve service performance and reliability, placing instances in multiple locations and redirecting clients to nearby copies. Anycast is a common mechanism used for redirecting clients in a variety of domains from naming to CDNs and video streaming. IP anycast offers a method for making a service IP address available to a routing system from several locations at once, and clients' requests are directed based on BGP routing policies. For operators, IP anycast offers an economic, scalable, and simple approach to replicated services; BGP provides considerable robustness, adapting to changes in service and network availability. For clients, however, the mapping can be suboptimal, unstable, and seemingly chaotic, as routing policies have not only technical motivations, and routing changes can silently shift traffic from one site to another with a consequent loss of shared state and potential performance impact. Given its wide deployment and interesting tradeoffs, IP anycast has been the focus of much recent measurement work. All prior studies have, nevertheless, focused on wired networks despite the growing dominance of mobile Internet. Today, the number of mobile subscriptions is over 7.4 billion, and users spend over 2x times more hours browsing on their smartphones than on any other device, with the corresponding increase on cellular traffic. We present early results on the first study of anycast performance for mobile users. Our evaluation focuses on two distinct anycast services, K-and F-Root, each providing part the DNS Root zone. Both services are widely replicated with publicly available site locations and unicast IP addresses that allow us to evaluate the relative performance of anycast routing to its "optimal" (in terms of unicast) site location. We collected active measurements from geographically distributed clients on both cellular and WiFi networks from September 2016 until April 2017, using the Aqualab’s ALICE engine [1]. In each experiment clients launched ping and traceroute measurements towards the root servers’ anycast addresses, as well as to five chosen unicast addresses determined to be the closest to the client in terms of geographic distance, at an hourly rate. Clients also recorded their geographic location, anonymized to a 10 km² area. Our findings show that mobile clients are routed to suboptimal replicas in terms of geographical distance, more frequently while on a cellular connection than on WiFi, with a significant impact on perceived service performance. The phenomenon seems to be more pronounced for K-Root than for F-Root. A possible explanation for the long distances would be that our cellular clients are simply far away from all the available replicas. However, our investigations demonstrate that this is not necessarily the case. Finally, we start to explore the root causes for anycast anomalies in cellular networks. We reveal three classes of anomalies: distant client packet gateways, poor anycast routing within Tier-1 networks, and improper routing out of cellular networks. [1] http://aqualab.cs.northwestern.edu/projects/261-alice [less ▲]

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See detailCoalescence in Highly Viscous System
Leleu, David ULiege; Pfennig, Andreas ULiege; Bruns, Nicole

Poster (2017, November)

study of the coalescence in liquid-liquid dispersion by comparing batch settling cell experiment with a numerical tool, based on ReDrop concept.

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See detailA mass spectrometry method for sensitive, specific and simultaneous detection of bovine blood meal, blood products and milk products in compound feed
Lecrenier, Marie-Caroline ULiege; Planque, Mélanie; Dieu, Marc et al

in Food Chemistry (2017)

Feed sustainability is one of the biggest challenges for the next few years. Solutions have to be found that take feed quality and safety into account. Animal by-products are one valuable source of ... [more ▼]

Feed sustainability is one of the biggest challenges for the next few years. Solutions have to be found that take feed quality and safety into account. Animal by-products are one valuable source of proteins. However, since the bovine spongiform encephalopathy (BSE) crisis, their use has been strictly regulated. The objective of this study was to propose a routine, sensitive and specific method using ultra-high performance liquid chromatography coupled to tandem mass spectrometry for the detection of blood-derived products and milk powder in feed. Contaminated aquafeeds were analysed in order to evaluate the sensitivity and specificity of the method. This new method meets both selectivity and sensitivity (0.1% (w/w)) requirements imposed by the European Commission for animal proteins detection methods. It offers an innovative and complementary solution for the simultaneously identification of authorised and unauthorised animal by-products such as processed animal proteins (PAPs). [less ▲]

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See detailVelléités d’indépendance, remise en question par les armes, guerres civiles : l’État semble de plus en plus contesté et menacé. Qu’en est-il vraiment ?
Wintgens, Sophie ULiege; Weerts, Audrey ULiege

E-print/Working paper (2017)

Dans un grand nombre d’études menées depuis plus d’une vingtaine d’années, la question de la place et du contrôle de l’État est formulée en termes de « crise ». Comment l’État du XXIe siècle fait-il face ... [more ▼]

Dans un grand nombre d’études menées depuis plus d’une vingtaine d’années, la question de la place et du contrôle de l’État est formulée en termes de « crise ». Comment l’État du XXIe siècle fait-il face aux pressions internationales (terrorisme, mondialisation, flux migratoires) et aux menaces internes (référendums d’indépendance, guerres civiles, ingérence étrangère)? "L’État dans tous ses états", un ouvrage collectif (publié chez Peter Lang en Belgique) dirigé par deux chercheuses belges, Sophie Wintgens et Audrey Weerts, essaie de répondre aux questions soulevées par l’actualité par des réflexions théoriques et des études de cas. Sophie Wintgens est chargée de recherches du Fonds de la recherche scientifique (FRS-FNRS) au Centre d’étude de la vie politique (CEVIPOL) de l’Université libre de Bruxelles, maître de conférences au département de science politique de l’Université de Liège et chercheuse associée au Center for International Relations Studies (CEFIR). Audrey Weerts est assistante et chargée de recherches au sein de la Cellule d’appui politologique Afrique-Caraïbes et de l’unité d’étude des systèmes politiques belges à l’Université de Liège. Toutes les deux expliquent à Middle East Eye que loin d’être une entité statique et figée, l’État se développe et se transforme, et reste encore pour l’instant un acteur central du système international. [less ▲]

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See detailLa vache Montbéliarde emportée par la génomique
Gaillard, Claire; Mougenot, Catherine ULiege; Petit, Sandrine

in Sesame Sciences et Société Alimentation Mondes agricoles et Environnement (2017), 2

La mise en œuvre de la sélection génomique basée sur une simple prise de sang constitue une étape majeure dans l’histoire de l’élevage bovin. C’est une véritable révolution qui s’accompagne de nombreux ... [more ▼]

La mise en œuvre de la sélection génomique basée sur une simple prise de sang constitue une étape majeure dans l’histoire de l’élevage bovin. C’est une véritable révolution qui s’accompagne de nombreux changements, qu’il s’agisse de la multiplicité des informations liées aux nouveaux outils, de la rapidité de leur renouvellement, de l’élargissement de l’offre génétique.Pour comprendre comment les outils génomiques s’imposent dans les pratiques de sélection et avec quelles implications, nous menons une recherche sur le terrain de la race Montbéliarde en Franche-Comté auprès d’éleveurs, d’inséminateurs et de techniciens-cadres des entreprises de sélection. [less ▲]

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See detailWhat does "Smart" mean in Rural Development?
Schmitz, Serge ULiege

Conference (2017, November)

For more than a decade, "smart development" is a leitmotiv in both the literature and political discourse. Besides the integration of ICT in everyday life, “smartness” seems to include many approaches ... [more ▼]

For more than a decade, "smart development" is a leitmotiv in both the literature and political discourse. Besides the integration of ICT in everyday life, “smartness” seems to include many approaches, which are sometimes in contradiction. Based on a systematic literature and internet review; this introduction scrutinizes the use of the fuzzy concept in rural development studies and questions the fate of geography in regard of this “marketing” development [less ▲]

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See detailUltra-High Performance Liquid Chromatography coupled to tandem Mass Spectrometry for the detection of animal by-products in feed
Lecrenier, Marie-Caroline ULiege; Planque, Mélanie; Dieu, Marc et al

in Book of abstracts of the 8th International Symposium on Recent advances in food analysis (2017, November)

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See detailENTOFÔR project -From waste to resource
Lecrenier, Marie-Caroline ULiege; Fumière, Olivier; Berntssen, M.H.G. et al

Poster (2017, November)

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See detailWho takes care of non-standard career paths? The role of labour market intermediaries
Lorquet, Nadège; Orianne, Jean-François ULiege; Pichault, François ULiege

in European Journal of Industrial Relations (2017)

As flexible career paths become more common in European labour markets, how to combine the flexibility required by non-standard work with new patterns of security is the focus of political debate. Some ... [more ▼]

As flexible career paths become more common in European labour markets, how to combine the flexibility required by non-standard work with new patterns of security is the focus of political debate. Some European Union (EU) countries have launched radical labour market reforms, while in others such reforms remain limited. This paves the way for bottom-up solutions developed by private and non-profit labour market intermediaries in order to support the job transitions of non-standard workers. We map these initiatives through a multidimensional grid and explore the extent to which they contribute to renewed regulation of modern labour markets. We outline two ideal-typical approaches. The first extends internal labour markets to triangular employment relationships by considering workers as ‘quasi-employees’. The second involves more disruptive solutions by treating non-standard workers as ‘quasi-self-employed’. [less ▲]

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See detailAnalyser et rédiger en recherche qualitative : le journal de bord de Cassandre
Lejeune, Christophe ULiege

Learning material (2017)

Développé par Christophe Lejeune, Cassandre est un logiciel d'analyse qualitative (libre, open source et gratuit). À la différence des logiciels envisageant l'analyse comme une étape séparée de la ... [more ▼]

Développé par Christophe Lejeune, Cassandre est un logiciel d'analyse qualitative (libre, open source et gratuit). À la différence des logiciels envisageant l'analyse comme une étape séparée de la recherche, la nouvelle version de Cassandre (3.0) accompagne le chercheur de ses premiers questionnements jusqu'à la publication des résultats. Plutôt que de rassembler un "corpus" et de retarder le saut interprétatif, l'analyse débute dès le premier jour de la recherche, avant même le premier contact avec le terrain. Le développement de Cassandre prolonge les enseignements méthodologiques du Manuel d'analyse qualitative (De Boeck, 2014), rédigé par Chr. Lejeune. Résolument qualitative, son approche invite à Analyser sans compter ni classer. La tenue du journal de bord réside au cœur du logiciel. En écrivant, le chercheur formule son questionnement, prépare le terrain, met en forme son matériau empirique, y repère les dimensions porteuses, les articule et les conceptualise. Encourager la collaboration et le débat scientifique. En tant que plateforme collaborative, Cassandre facilite le travail en équipe. Ces fonctionnalités profitent également au chercheur isolé. Cassandre lui permet en effet partager des résultats intermédiaires avec des informateurs, un client, des collègues, un comité d'accompagnement ou un directeur de thèse. Leurs commentaires l'encouragent à affiner son analyse au fil de l'eau. Pour une recherche qualitative rigoureuse & créative ! Favorisant une organisation souple du travail scientifique, le logiciel Cassandre participe à l'émergence d'idées neuves. Chaque étape du processus de recherche est documentée dans le journal de bord. L'ancrage et la validation de la démarche du chercheur sont de la sorte assurés : "En documentant le maillage entre le terrain et la théorie, les traces en question assurent que la théorie s'appuie toujours sur des éléments attestés". (Chr. Lejeune, op. cit. p. 29) [less ▲]

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See detailInfluence de la géométrie du quadrant amont et comportement hydraulique sous forte charge des seuils profilés standard
Erpicum, Sébastien ULiege; Pirotton, Michel ULiege; Blancher, Benoit et al

in Loudière, Daniel (Ed.) Hydraulique des barrages et des digues (2017, November)

In order to study the variation of the hydraulic characteristics of ogee-crested weirs for upstream heads higher than the design head, several profiles have been tested on an experimental facility ... [more ▼]

In order to study the variation of the hydraulic characteristics of ogee-crested weirs for upstream heads higher than the design head, several profiles have been tested on an experimental facility specifically designed and instrumented. These profiles have been defined regarding the real profiles of spillways of dams operated by EDF as well as the most used geometry of the literature. The experimental tests have been supplemented by numerical modeling, whose results were found to be very similar. The analysis shows that the discharge coefficient increases with the upstream head until head ratios around 5.5. This evolution follows very well the power equations from the literature. For higher head ratios, the discharge coefficient abruptly decreases from a value around 0.6 to a value around 0.55. This decrease corresponds to the apparition between the main flow and the weir of a low velocity area (the lower nappe does no more correspond to the weir profile). The analysis also shows a significant reduction of the discharge coefficient (around 10%) if the upstream quadrant design head is higher than 2 times the design head of the downstream quadrant. On the contrary, no modification of the discharge coefficient is measured if the upstream quadrant design head is smaller than the downstream quadrant one. [less ▲]

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