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See detailAn Investigation of Compression Techniques to Speed up Mutation Testing
Zhu; Panichella, Annibale UL; Zaidman, Andy

in 11th IEEE Conference on Software Testing, Validation and Verification, 2018 (in press)

Mutation testing is widely considered as a high-end test coverage criterion due to the vast number of mutants it generates. Although many efforts have been made to reduce the computational cost of ... [more ▼]

Mutation testing is widely considered as a high-end test coverage criterion due to the vast number of mutants it generates. Although many efforts have been made to reduce the computational cost of mutation testing, in practice, the scalability issue remains. In this paper, we explore whether we can use compression techniques to improve the efficiency of strong mutation based on weak mutation information. Our investigation is centred around six mutation compression strategies that we have devised. More specifically, we adopt overlapped grouping and Formal Concept Analysis (FCA) to cluster mutants and test cases based on the reachability (code covergae) and necessity (weak mutation) conditions. Moreover, we leverage mutation knowledge (mutation locations and mutation operator types) during compression. To evaluate our method, we conducted a study on 20 open source Java projects using manually written tests. We also compare our method with pure random sampling and weak mutation. The overall results show that mutant compression techniques are a better choice than random sampling and weak mutation in practice: they can effectively speed up strong mutation 6.3 to 94.3 times with an accuracy of >90%. [less ▲]

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See detailPartizipation in Großschutzgebieten - untersucht am Beispiel der Beteiligung an den Workshops zur Erstellung des Rahmenkonzeptes des Biosphärenreservates Bliesgau 2014
Nienaber, Birte UL

in Weber, Friedericke; Weber, Florian; Jenal, Corinna (Eds.) Wohin des Weges? Regionalentwicklung in Großschutzgebieten (in press)

In 2014 a process of public participation was initiated in order to produce a framework concept for the future configuration of the “Biosphere Bliesgau”. This paper presents characteristics of ... [more ▼]

In 2014 a process of public participation was initiated in order to produce a framework concept for the future configuration of the “Biosphere Bliesgau”. This paper presents characteristics of participation, both in general and in large-scale protected areas in particular, and discusses what various forms of participation (ranging from pure information as non-participation to bottom-up partnerships as the strongest form of participation) are possible. The empirical-analytical section of the paper investigates the 2014 process of participation in Biosphere Bliesgau, using publically available protocols and interviews. It can be seen that the top-down process – e. g. involving concrete agreements between individuals or groups – involves the selection of participants – intended or otherwise – and that the highest level of participation could therefore not be achieved. [less ▲]

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See detailA generalization of the concept of distance based on the simplex inequality
Kiss, Gergely UL; Marichal, Jean-Luc UL; Teheux, Bruno UL

in Beiträge zur Algebra und Geometrie / Contributions to Algebra and Geometry (in press)

We introduce and discuss the concept of \emph{$n$-distance}, a generalization to $n$ elements of the classical notion of distance obtained by replacing the triangle inequality with the so-called simplex ... [more ▼]

We introduce and discuss the concept of \emph{$n$-distance}, a generalization to $n$ elements of the classical notion of distance obtained by replacing the triangle inequality with the so-called simplex inequality \[ d(x_1, \ldots, x_n)~\leq~K\, \sum_{i=1}^n d(x_1, \ldots, x_n)_i^z{\,}, \qquad x_1, \ldots, x_n, z \in X, \] where $K=1$. Here $d(x_1,\ldots,x_n)_i^z$ is obtained from the function $d(x_1,\ldots,x_n)$ by setting its $i$th variable to $z$. We provide several examples of $n$-distances, and for each of them we investigate the infimum of the set of real numbers $K\in\left]0,1\right]$ for which the inequality above holds. We also introduce a generalization of the concept of $n$-distance obtained by replacing in the simplex inequality the sum function with an arbitrary symmetric function. [less ▲]

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See detailLessons from social network analysis to Industry 4.0
Omar, Yamila UL; Minoufekr, Meysam UL; Plapper, Peter UL

in Manufacturing Letters (in press)

With the advent of Industry 4.0, a growing number of sensors within modern production lines generate high volumes of data. This data can be used to optimize the manufacturing industry in terms of complex ... [more ▼]

With the advent of Industry 4.0, a growing number of sensors within modern production lines generate high volumes of data. This data can be used to optimize the manufacturing industry in terms of complex network topology metrics commonly used in the analysis of social and communication networks. In this work, several such metrics are presented along with their appropriate interpretation in the field of manufacturing. Furthermore, the assumptions under which such metrics are defined are assessed in order to determine their suitability. Finally, their potential application to identify performance limiting resources, allocate maintenance resources and guarantee quality assurance are discussed. [less ▲]

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See detailConstructions contestées et contrastées de la notion de terroir. Symbolique Politique, Savoir Scientifique, Typicité Culturale et Culturelle
Reckinger, Rachel UL

in Yengué, Louis; Stengel, Kilien (Eds.) Terroir viticole. Espace et figures de qualité (2018)

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See detail‘Pas de fraises pour Noël’. Le rôle de la régionalité locavore dans la (re)prise de conscience de la saisonnalité des aliments 
Reckinger, Rachel UL

in Adamiec, Camille; Julien, Marie-Pierre; Régnier, Faustine (Eds.) L’alimentation au fil des saisons. La saisonnalité des pratiques alimentaires (2018)

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See detailThe Metonymical Institutionnalisation of Wine Production and Consumption in Luxembourg. Convergence of Terroir Typicity, Political Symbolism, Regulations and Scientific Knowledge
Reckinger, Rachel UL

in Tedeschi, Paolo (Ed.) The Evolution of the Viticulture and Winemaking in Europe: Production, Retail System, Oenological Techniques, Terroir and Local Culture (19th-20th Centuries) (2018)

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See detailTowards the Systematic Analysis of Non-Functional Properties in Model-Based Engineering for Real-Time Embedded Systems
Brau, Guillaume UL; Navet, Nicolas UL; Hugues, Jérôme

in Science of Computer Programming (2018), 156

The real-time scheduling theory provides analytical methods to assess the temporal predictability of embedded systems. Nevertheless, their use is limited in a Model-Based Systems Engineering approach. In ... [more ▼]

The real-time scheduling theory provides analytical methods to assess the temporal predictability of embedded systems. Nevertheless, their use is limited in a Model-Based Systems Engineering approach. In fact, the large number of applicability conditions makes the use of real-time scheduling analysis tedious and error-prone. Key issues are left to the engineers: when to apply a real-time scheduling analysis? What to do with the analysis results?} This article presents an approach to systematize and then automate the analysis of non-functional properties in Model-Based Systems Engineering. First, preconditions and postconditions define the applicability of an analysis. In addition, contracts specify the analysis interfaces, thereby enabling to reason about the analysis process. We present a proof-of-concept implementation of our approach using a combination of constraint languages (REAL for run-time analysis) and specification languages (Alloy for describing interfaces and reasoning about them). This approach is experimented on architectural models written with the Architecture Analysis and Design Language (AADL). [less ▲]

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See detailDe gevolgen van de restkracht bij een paalfundering
Rica, Shilton UL; Van Baars, Stefan UL

in Geotechniek (2018), Maart

Alhoewel de funderingspaal al lang in gebruik is, is de bepaling van de draagkracht nog steeds een complexe zaak. Uit een verzameling eerder gemaakte veldproeven, die in Nederland, België en Frankrijk ... [more ▼]

Alhoewel de funderingspaal al lang in gebruik is, is de bepaling van de draagkracht nog steeds een complexe zaak. Uit een verzameling eerder gemaakte veldproeven, die in Nederland, België en Frankrijk waren uitgevoerd, werd de conclusie getrokken dat het berekende puntdraagvermogen, per 2017, met 30% gereduceerd moest worden. Bij deze proeven werd verondersteld dat de spanningen op de onbelaste paal na installatie kunnen worden verwaarloosd, en daarmee ook de resulterende restkracht in de paal. Uit andere veldproeven genoemd in de wetenschappelijke literatuur, blijkt echter dat deze restkracht niet te verwaarlozen is. Numerieke berekeningen uit deze publicatie ondersteunen deze conclusie. Deze verwaarlozing leidt nu tot een te klein puntdraagvermogen, en een te groot schachtdraagvermogen. Naast het probleem van de verwaarlozing van de restkracht speelt er nog een belangrijk probleem: de gehanteerde invloedszone bij de methode Koppejan is gebaseerd op een destijds aangenomen bezwijkmechanisme, die volgens numerieke berekeningen uit deze publicatie onjuist is. Dit leidt tot nog meer onnauwkeurigheden. [less ▲]

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See detailLa référence à l’Alsace-Lorraine dans le rattachement et l’intégration d’Eupen-Malmedy à la Belgique (1918-1925)
Brüll, Christoph UL

Scientific Conference (2018, February 09)

En novembre 1910, le Journal des Tribunaux, principal organe d’information des juristes belges, qualifie la partie wallonne du Kreis allemand de Malmedy de « notre Alsace-Lorraine » où se trouveraient des ... [more ▼]

En novembre 1910, le Journal des Tribunaux, principal organe d’information des juristes belges, qualifie la partie wallonne du Kreis allemand de Malmedy de « notre Alsace-Lorraine » où se trouveraient des « frères de race et de langue, exilés et emprisonnés en Prusse. » Le 20 septembre 1920, ce Kreis ainsi que celui d’Eupen, presque exclusivement germanophone, sont rattachés à la Belgique, suite au traité de Versailles et à un simulacre de consultation populaire. Dans notre contribution qui traitera de la période qui s’étend de l’occupation de la région par des troupes belges en août 1919 à la fin du régime transitoire en mars 1925, nous voudrions nous interroger sur la signification de la référence à l’Alsace-Lorraine pendant cette phase du changement de la nationalité. Des indices donnent à penser que cette référence n’est pas limitée aux discours de légitimation de l’annexion du territoire par la Belgique, mais que les autorités belges ont, à certaines occasions (comme l’introduction du service militaire), contacté leurs homologues français afin de connaître la politique d’intégration menée en Alsace-Lorraine. En revanche, il n’y a jamais eu d’étude systématique de cette référence idéelle et pratique. Notre proposition voudrait combler cette lacune et constituerait également une contribution à une histoire comparée de la transition étatique dans les deux territoires. [less ▲]

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See detailSimulation-Based Fault Injection as a Verification Oracle for the Engineering of Time-Triggered Ethernet networks
Fejoz, Loïc; Regnier, Bruno; Miramont, Philippe et al

Scientific Conference (2018, February 02)

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise ... [more ▼]

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise understanding of TTE’s functioning and its performances in nominal and error conditions. This holds especially true for the clock synchronization algorithm, the cornerstone of time-triggered communication in TTE, which involves complex distributed algorithms. In this study, we use both an experimental platform and fault-injection on a simulation model to gain quantified insights in these questions. We first describe a fine-grained simulation model of TTE model and discuss how it has been validated against communication traces recorded on the TTE platform. We then present experiments that evaluate the accuracy of the clock synchronization in TTE in the fault-free case as well as considering permanent link failure and transient transmission errors. Finally, we discuss what we have learned during the project in terms of development process and programming language support for complex simulation models used in the design of critical systems. [less ▲]

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See detailInsights on the Performance and Configuration of AVB and TSN in Automotive Ethernet Networks
Migge, Jörn; Villanueva, Josetxo; Navet, Nicolas UL et al

Scientific Conference (2018, February 02)

Switched Ethernet is profoundly reshaping in-car communications. To meet the diverse real-time requirements in automotive communications, Quality-of-Service protocols that go beyond the mere use of ... [more ▼]

Switched Ethernet is profoundly reshaping in-car communications. To meet the diverse real-time requirements in automotive communications, Quality-of-Service protocols that go beyond the mere use of priorities are required. In this work, the basic questions that we investigate on a case-study with diverse and demanding communication requirements is what can we expect from the various protocols aimed at providing a better timing Quality of Service on top of Ethernet? And how to use them? Especially how to use them in a combined manner. We will focus on the Credit-Based Shaper of AVB, the Time-Aware Shaper of TSN and the use of priorities as defined in IEEE802.1Q. The performance metrics considered are the distributions of the communication latencies, obtained by simulation, as well as upper bounds on these quantities obtained by worst-case schedulability analysis. If there have been over the last 5 years numerous studies on the performance of AVB CBS, the literature on comparing AVB to TSN and other candidate protocols is still sparse. To the best of our knowledge, this empirical study is the first to consider most protocols currently considered in the automotive domain, with the aim to gain insights into the different technological, design and configurations alternatives. In particular, an objective of this study is to identify key problems that need to be solved in order to further automate network design and configuration. [less ▲]

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See detailBeware: Nobody Wants to Be Lonely
Tkalec, Igor UL

Article for general public (2018)

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See detailAttacks and Countermeasures for White-box Designs
Biryukov, Alex UL; Udovenko, Aleksei UL

E-print/Working paper (2018)

In the traditional symmetric cryptography, the adversary has access only to the inputs and outputs of a cryptographic primitive. In the white-box model the adversary is given full access to the ... [more ▼]

In the traditional symmetric cryptography, the adversary has access only to the inputs and outputs of a cryptographic primitive. In the white-box model the adversary is given full access to the implementation. He can use both static and dynamic analysis as well as fault analysis in order to break the cryptosystem, e.g. to extract embedded secret key. Implementations secure in such model have many applications in industry. However, creating such implementations turns out to be a very challenging if not an impossible task. Recently, Bos et al. proposed a generic attack on white-box primitives called differential computation analysis (DCA). This attack applies to most existent white-box implementations both from academia and industry. The attack comes from side-channel cryptanalysis method. The most common method protecting against such side-channel attacks is masking. Therefore, masking can be used in white-box implementations to protect against the DCA attack. In this paper we investigate this possibility and present multiple generic attacks against masked white-box implementations. We use the term “masking” in a very broad sense. As a result, we deduce new constraints that any secure white-box implementation must satisfy. We suggest partial countermeasures against the attacks. Some of our attacks were successfully applied to the WhibOx 2017 challenges. [less ▲]

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See detailSurmonter les barrières linguistiques avec « MaGrid » - un outil de formation de pré-mathématiques pour un contexte scolaire multilingue
Cornu, Véronique UL; Pazouki, Tahereh UL; Schiltz, Christine UL et al

Scientific Conference (2018, January 11)

Le contexte scolaire luxembourgeois est caractérisé par le multilinguisme et une population scolaire hétérogène, ce qui nécessite la mise en place de pratiques pédagogiques qui prennent en compte ... [more ▼]

Le contexte scolaire luxembourgeois est caractérisé par le multilinguisme et une population scolaire hétérogène, ce qui nécessite la mise en place de pratiques pédagogiques qui prennent en compte l’hétérogénéité des élèves. Dans le domaine des mathématiques, qui semble être non-verbal à première vue, des résultats scientifiques montrent que les enfants dont la langue maternelle est différente de la langue d’instruction, atteignent sur des tests d’aptitudes pré-mathématiques des résultats significativement inférieurs à ceux de leurs camarades natifs. Ceci est d’autant plus inquiétant, sachant que ces aptitudes pré-mathématiques sont prédictives des apprentissages ultérieurs. Par conséquent, nous avons développé l’outil de formation de pré-mathématiques non-verbale « MaGrid ». « MaGrid » permet à chaque enfant de bénéficier pleinement d’une instruction préscolaire en mathématiques, indépendamment de ses compétences langagières. Cet outil se caractérise par sa nature visuelle et il est implémenté sur tablette tactile. Jusqu’à présent, nous avons implémenté et évalué « MaGrid » lors de deux études scientifiques. Les résultats quantitatifs des évaluations empiriques sont prometteurs, comme ils montrent des effets positifs sur les habilités entraînées chez les enfants ayant utilisé cet outil comparé à un groupe contrôle. Dans une première étude, l’outil a été utilisé auprès de cinq classes durant 10 semaines, comprenant deux séances de 20 minutes par semaine. Les résultats lors de petites épreuves spécifiques ont été comparés aux résultats d’élèves de cinq classes n’ayant pas d’entraînement spécifique, et des effets d’intervention ont été observés. Dans une deuxième étude, nous nous sommes focalisés sur un groupe d’enfants de langue minoritaire (le portugais). « MaGrid » a été utilisé lors d’un programme d’intervention de pré-mathématiques s’étendant sur les deux années scolaires de l’école préscolaire. Les analyses préliminaires ont abouti à des résultats positifs. Des effets bénéfiques se sont manifestés sur différentes mesures de pré-mathématiques chez les enfants ayant suivi notre programme par rapport aux enfants du groupe contrôle. [less ▲]

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See detailTransforming Time Series for Efficient and Accurate Classification
Li, Daoyuan UL

Doctoral thesis (2018)

Time series data refer to sequences of data that are ordered either temporally, spatially or in another defined order. They can be frequently found in a variety of domains, including financial data ... [more ▼]

Time series data refer to sequences of data that are ordered either temporally, spatially or in another defined order. They can be frequently found in a variety of domains, including financial data analysis, medical and health monitoring and industrial automation applications. Due to their abundance and wide application scenarios, there has been an increasing need for efficient machine learning algorithms to extract information and build knowledge from these data. One of the major tasks in time series mining is time series classification (TSC), which consists of applying a learning algorithm on labeled data to train a model that will then be used to predict the classes of samples from an unlabeled data set. Due to the sequential characteristic of time series data, state-of-the-art classification algorithms (such as SVM and Random Forest) that performs well for generic data are usually not suitable for TSC. In order to improve the performance of TSC tasks, this dissertation proposes different methods to transform time series data for a better feature extraction process as well as novel algorithms to achieve better classification performance in terms of computation efficiency and classification accuracy. In the first part of this dissertation, we conduct a large scale empirical study that takes advantage of discrete wavelet transform (DWT) for time series dimensionality reduction. We first transform real-valued time series data using different families of DWT. Then we apply dynamic time warping (DTW)-based 1NN classification on 39 datasets and find out that existing DWT-based lossy compression approaches can help to overcome the challenges of storage and computation time. Furthermore, we provide assurances to practitioners by empirically showing, with various datasets and with several DWT approaches, that TSC algorithms yield similar accuracy on both compressed (i.e., approximated) and raw time series data. We also show that, in some datasets, wavelets may actually help in reducing noisy variations which deteriorate the performance of TSC tasks. In a few cases, we note that the residual details/noises from compression are more useful for recognizing data patterns. In the second part, we propose a language model-based approach for TSC named Domain Series Corpus (DSCo), in order to take advantage of mature techniques from both time series mining and Natural Language Processing (NLP) communities. After transforming real-valued time series into texts using Symbolic Aggregate approXimation (SAX), we build per-class language models (unigrams and bigrams) from these symbolized text corpora. To classify unlabeled samples, we compute the fitness of each symbolized sample against all per-class models and choose the class represented by the model with the best fitness score. Through extensive experiments on an open dataset archive, we demonstrate that DSCo performs similarly to approaches working with original uncompressed numeric data. We further propose DSCo-NG to improve the computation efficiency and classification accuracy of DSCo. In contrast to DSCo where we try to find the best way to recursively segment time series, DSCo-NG breaks time series into smaller segments of the same size, this simplification also leads to simplified language model inference in the training phase and slightly higher classification accuracy. The third part of this dissertation presents a multiscale visibility graph representation for time series as well as feature extraction methods for TSC, so that both global and local features are fully extracted from time series data. Unlike traditional TSC approaches that seek to find global similarities in time series databases (e.g., 1NN-DTW) or methods specializing in locating local patterns/subsequences (e.g., shapelets), we extract solely statistical features from graphs that are generated from time series. Specifically, we augment time series by means of their multiscale approximations, which are further transformed into a set of visibility graphs. After extracting probability distributions of small motifs, density, assortativity, etc., these features are used for building highly accurate classification models using generic classifiers (e.g., Support Vector Machine and eXtreme Gradient Boosting). Based on extensive experiments on a large number of open datasets and comparison with five state-of-the-art TSC algorithms, our approach is shown to be both accurate and efficient: it is more accurate than Learning Shapelets and at the same time faster than Fast Shapelets. Finally, we list a few industrial applications that relevant to our research work, including Non-Intrusive Load Monitoring as well as anomaly detection and visualization by means for hierarchical clustering for time series data. In summary, this dissertation explores different possibilities to improve the efficiency and accuracy of TSC algorithms. To that end, we employ a range of techniques including wavelet transforms, symbolic approximations, language models and graph mining algorithms. We experiment and evaluate our approaches using publicly available time series datasets. Comparison with the state-of-the-art shows that the approaches developed in this dissertation perform well, and contribute to advance the field of TSC. [less ▲]

See detailHistoriker und die Konstruktion von Zeitgenossenschaft. Eine Projektskizze am Beispiel der Militärverwaltung Belgien-Nordfrankreich im Zweiten Weltkrieg
Brüll, Christoph UL

Presentation (2018, January 09)

Gegenstand des Projekts ist die Konstruktion des Zeitzeugendiskurses mehrerer führender Mitglieder der deutschen Militärverwaltung in Brüssel. Arbeitshypothese ist, dass die Konstruktion in drei Phasen ... [more ▼]

Gegenstand des Projekts ist die Konstruktion des Zeitzeugendiskurses mehrerer führender Mitglieder der deutschen Militärverwaltung in Brüssel. Arbeitshypothese ist, dass die Konstruktion in drei Phasen verlief: Der „Generalprozess“ (1950-1951) gegen Alexander von Falkenhausen und Eggert Reeder (gefolgt von einer Reihe anderer Prozesse bis in die 1980er Jahre hinein). Die Legitimierungs- und Verteidigungsdiskurse einiger Akteure gegenüber Anschuldigungen, die ihre Tätigkeiten während des Krieges betrafen. Ihre Tätigkeit als Zeitzeuge für belgische und deutsche Historiker und Journalisten seit den 1970er Jahren. [less ▲]

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See detailProceedings - 2017 ILILAS Distinguished Lectures
Bouvry, Pascal UL; Bisdorff, Raymond; Schommer, Christoph UL et al

Report (2018)

The Proceedings summarizes the 12 lectures that have taken place within the ILIAS Dinstguished Lecture series 2017. It contains a brief abstract of the talks as well as some additional information about ... [more ▼]

The Proceedings summarizes the 12 lectures that have taken place within the ILIAS Dinstguished Lecture series 2017. It contains a brief abstract of the talks as well as some additional information about each speaker. [less ▲]

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See detailBrexit Seen from Luxembourg
Högenauer, Anna-Lena UL

E-print/Working paper (2018)

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