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See detailPlayers' moral decisions in virtual worlds: Morality in video games
Melzer, André UL; Holl, Elisabeth UL

Book published by Oxford University Press (2020)

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See detailValue-added modeling in primary school: What covariates to include?
Levy, Jessica UL; Brunner, Martin; Keller, Ulrich UL et al

Scientific Conference (2019, August)

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See detailBracketing in student writing: its uses (and abuses)
Deroey, Katrien UL

Scientific Conference (2019, July 23)

This paper reports on the use of bracketed text in a large corpus of student writing. The function of bracketing has been neglected in academic writing research and coursebooks. Yet it is closely related ... [more ▼]

This paper reports on the use of bracketed text in a large corpus of student writing. The function of bracketing has been neglected in academic writing research and coursebooks. Yet it is closely related to important text construction issues such as information packaging, coherence, clarity, conciseness, intertextual framing and sourcing. With a view to informing academic writing description and instruction, we examined the relationship between bracketed text and its cotext in a wide variety of disciplines and assignment genres. The relationships are described using an adaptation of Halliday and Matthiessen’s (2014) logico-semantic framework of clausal relationships. To better understand and teach the use of this information packaging feature, we studied the relationship between bracketed text and its cotext in the British Academic Written English (BAWE) corpus of high-graded student assignments. Using Sketch Engine and corpus query language, we extracted a random sample of 2000 instances of bracketing in running text only. This subcorpus is composed of 500 instances from each of the four main disciplinary groupings (Arts and Humanities, Life Sciences, Physical Sciences, Social Sciences) and contains instances from most of the BAWE assignment genres. The concordances were imported into a database table in FileMaker Pro. This database programme facilitates coding by limiting choices depending on previous selections and thus guiding the coder through the analytical steps. For the analysis of the data, it offers flexibility for grouping records and aggregating results on different levels. The logico-semantic framework used in systemic functional linguistics to classify the relationships between clauses (Halliday & Matthiessen, 2014) served as our starting point to classify the relationships between bracketed text and cotext. This framework distinguishes two fundamental logico-semantic relationships: expansion, which ‘relates phenomena as being of the same order of experience’, and projection, which ‘relates phenomena of one order of experience (the processes of saying and thinking) to phenomena of a higher order (semiotic phenomena – what people say and think)’ (p. 443). The latter contains three subtypes: elaboration (‘one clause elaborates on the meaning of another by further specifying or describing it’) (p. 461), enhancement (‘one clause (or subcomplex) enhances the meaning of another by qualifying it) (p. 476) and extension (‘one clause extends the meaning of another by adding something new to it’) (p. 471). This framework was refined and expanded through several stages of interrating and discussion in order to reflect our findings. We first analysed a random sample of 1000 instances from the whole BAWE corpus. With the resulting adapted classificatory framework we next independently analysed a quarter of our subcorpus of 2000 concordances. This led to further refinement of the framework and classificatory criteria. Finally, we each analyzed a different set of concordances from the disciplinary groupings. Disciplinary informants were consulted where needed. Our analysis revealed four major logico-semantic relationships between the bracketed text and cotext: in addition to Halliday & Matthiessen’s (2014) projection (1) and expansion (elaboration (2), enhancement (3, 4), extension (5)), we identified bracketed text functioning as intratextual reference (6) and code (7). The few instances that could not be confidently classified were assigned to a ‘hard to classify’ category. (1) However the anticipated number of children per woman in Europe and the USA is still near or above two (Bongaarts, 1999), showing that many are still having children. (2) Many of these injures are healed fractures and breaks occurring around the torso (upper body). (3) It is dated to the reign of Nectanebo II (360-343 BC). (4) Acetanilide (4.78g, 35.4 mmol) was dissolved in cold, glacial acetic acid (25ml, 437.1 mmol) (5) Parmenides decision to include a cosmology that he has already (apparently) proved to be flawed is an interesting one to say the least. (6) This is called circular polarization (figure 5) and is the natural state of white light. (7) Stronger field ligands such as (PPh 3) and (NCS) increase the splitting. Projection was –perhaps not surprisingly- the most common relationship by far, although markedly less frequent in the Physical Sciences. Expansion was mainly achieved through elaboration, with restatements (2) and abbreviations predominating. Enhancement relationships were mostly temporal locations (3) or measurements (4). Extension was relatively rare (5). Intratextual references (6) took various forms, such as figures, appendices, equations, and line numbers for quoted text. Bracketed code was a marked feature of the Physical Sciences, occurring in formulae and enclosing symbols or abbreviations (7). Overall, students’ use of bracketed text appeared to reflect disciplinary conventions and reflected the genre goals of assignments by demonstrating knowledge, understanding and appropriate source use. Contrary to expectations, instances where the bracketed text seemed superfluous or adversely affected coherence were rare. We conclude by discussing what these findings mean for academic writing instruction. Reference Halliday, M. A. K., & Matthiessen, C. M. I. M. (2014). Halliday's introduction to functional grammar (4 ed.). Abingdon: Routledge. [less ▲]

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See detailBayesian Identification of Mean-Field Homogenization model parameters and uncertain matrix behavior in non-aligned short fiber composites
Mahamedou, Mohamed; Zulueta Uriondo, Kepa; Chung, Chi Nghia et al

in Composite Structures (2019), 220

We present a stochastic approach combining Bayesian Inference (BI) with homogenization theories in order to identify, on the one hand, the parameters inherent to the model assumptions and, on the other ... [more ▼]

We present a stochastic approach combining Bayesian Inference (BI) with homogenization theories in order to identify, on the one hand, the parameters inherent to the model assumptions and, on the other hand, the composite material constituents behaviors, including their variability. In particular, we characterize the model parameters of a Mean-Field Homogenization (MFH) model and the elastic matrix behavior, including the inherent dispersion in its Young's modulus, of non-aligned Short Fibers Reinforced Polymer (SFRP) composites. The inference is achieved by considering as observations experimental tests conducted at the SFRP composite coupons level. The inferred model and material law parameters can in turn be used in Mean-Field Homogenization (MFH)-based multi-scale simulations and can predict the confidence range of the composite material responses. [less ▲]

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See detailTogether or Alone: The Price of Privacy in Collaborative Learinig
Pejo, Balazs UL; Tang, Qiang; Biczók, Gergely

in Proceedings on Privacy Enhancing Technologies (2019, July)

Machine learning algorithms have reached mainstream status and are widely deployed in many applications. The accuracy of such algorithms depends significantly on the size of the underlying training ... [more ▼]

Machine learning algorithms have reached mainstream status and are widely deployed in many applications. The accuracy of such algorithms depends significantly on the size of the underlying training dataset; in reality a small or medium sized organization often does not have the necessary data to train a reasonably accurate model. For such organizations, a realistic solution is to train their machine learning models based on their joint dataset (which is a union of the individual ones). Unfortunately, privacy concerns prevent them from straightforwardly doing so. While a number of privacy-preserving solutions exist for collaborating organizations to securely aggregate the parameters in the process of training the models, we are not aware of any work that provides a rational framework for the participants to precisely balance the privacy loss and accuracy gain in their collaboration. In this paper, by focusing on a two-player setting, we model the collaborative training process as a two-player game where each player aims to achieve higher accuracy while preserving the privacy of its own dataset. We introduce the notion of Price of Privacy, a novel approach for measuring the impact of privacy protection on the accuracy in the proposed framework. Furthermore, we develop a game-theoretical model for different player types, and then either find or prove the existence of a Nash Equilibrium with regard to the strength of privacy protection for each player. Using recommendation systems as our main use case, we demonstrate how two players can make practical use of the proposed theoretical framework, including setting up the parameters and approximating the non-trivial Nash Equilibrium. [less ▲]

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See detailExpansion nach Belgien als Verwaltungstätigkeit: der Kölner Beamte Franz Thedieck im NS
Brüll, Christoph UL

Scientific Conference (2019, June 28)

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See detailBenefits, challenges, social learning and controversies around Local Food Systems
Reckinger, Rachel UL; Nemes, Gusztav; Lajos, Veronika

Scientific Conference (2019, June 25)

Objectives: Our WG touches upon three main elements among the themes of the conference: (1) innovation, (2) social justice and (3) knowledge production. Innovative local food systems and alternative food ... [more ▼]

Objectives: Our WG touches upon three main elements among the themes of the conference: (1) innovation, (2) social justice and (3) knowledge production. Innovative local food systems and alternative food networks, approached from a collaborative and participatory angle, bring about a cultural shift by associating prosumers through a renewed form of trust, reciprocity and community, thus reinforcing social and ecological justice. At the same time, such heterodox actors in the transition to more sustainable food systems create new forms of knowledge, that are contested, co-constructed and potentially conflictual – along with enabling or disabling policymaking and, often, in dialogue with research. Our main objective is in this topic to start the process of creating an edited special issue of a peer reviewed journal (Sociologia Ruralis, Studies of Agricultural Economics or similar) should raise from this WG. We invite researchers working in the area of (local) food systems, alternative food networks, short food supply chains and related topics (rural tourism, community supported agriculture, etc.). We consider both the benefits and possible conflicts/problems in the connected socio-economic, cultural and environmental processes and welcome theoretical papers and case studies, too. Topic: By welcoming case studies from all geographical areas, in a comparative manner, this Working Group’s aim is to address different understandings and dynamics happening within and around different types of Local Food Systems (LFS). Alternative food networks, local food systems and short food supply chains have long been viewed as a sustainable, green way of raising the value added and creating opportunities for sur/re-vival of rural economy and society. They induce many benefits in terms of environmental impact, cultural exemplification, ethical entrepreneurship, social justice or rural development. Conceptually, LFS can be understood as ‘local food for local people’, as for example in the Slow Food or the community supported agriculture (CSA) movements. They are then associated with low food miles, environmental protection (Jones 2002), enhanced social networks and revitalised local communities (Fenstra 1997). From a local economic development perspective, in particular when LFS produce high quality products, they can equally be considered as ‘local food for non-local people’, either transported to urban centres, or attracting flows of tourists into rural areas. Here LFS can still enhance local businesses, economic and rural development, yet social and environmental benefits (Guthman 2004) of such foodstuffs, marketed with the added value of environmental and social responsibility, are more difficult to trace. Therefore, besides benefits, we would also like to analyse potential dissonances, that the distinction between local or extra-local target groups help to identify – for instance: • established, certified organic producers might criticize non-certified yet organically producing CSAs as fragmenting an already minority market or showing a lack of solidarity by not contributing to organic labels; • when LFS end up producing high quality, expensive products, a dynamic of social exclusion might occur, favoring the wealthy; • enhanced local production, tourism, and visitor pressure can cause social, economic, and environmental degradation, multiplier effects do not always occur to build more businesses and sustain social and economic capital; • innovative alternative food networks tend to struggle with territorial competition over land and resources, but if they rely on external investments, they might additionally be confronted – more insidiously – with the risk of co-option by neoliberal corporate agendas. We welcome analyses focusing on negotiations and struggles among actors in a multifaceted foodscape, where some block and some enhance transitions. Viewing the relationships, interconnectedness and agency of niche innovations, local and non-local appropriations as well regime hegemonies opens up the theoretical perspective of contested knowledge claims. We look for questions and answers including: • How are dynamics of “knowing and growing food in a contested arena” (Goodman, DuPuis, Goodman, 2014) negotiated – sometimes in a mutually enhancing and locally beneficial way, sometimes in more conflictual ways? • What are the local and extra-local stakeholders’ (producers, intermediaries, customers, tourists) different and often conflicting interests and responsibilities in LFS? • What can we learn from the tensions and local problems of LFS in order to support relevant policies to solve current controversies within the sector? • How can rural sociologists use their knowledge and influence to support local rural stakeholders of LFS? [less ▲]

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See detailEstimating fibres' material parameter distributions from limited data with the help of Bayesian inference
Rappel, Hussein UL; Beex, Lars UL

in European Journal of Mechanics. A, Solids (2019), 75

Numerous materials are essentially structures of discrete fibres, yarns or struts. Considering these materials at their discrete scale, one may distinguish two types of intrinsic randomness that affect ... [more ▼]

Numerous materials are essentially structures of discrete fibres, yarns or struts. Considering these materials at their discrete scale, one may distinguish two types of intrinsic randomness that affect the structural behaviours of these discrete structures: geometrical randomness and material randomness. Identifying the material randomness is an experimentally demanding task, because many small fibres, yarns or struts need to be tested, which are not easy to handle. To avoid the testing of hundreds of constituents, this contribution proposes an identification approach that only requires a few dozen of constituents to be tested (we use twenty to be exact). The identification approach is applied to articially generated measurements, so that the identified values can be compared to the true values. Another question this contribution aims to answer is how precise the material randomness needs to be identified, if the geometrical randomness will also influence the macroscale behaviour of these discrete networks. We therefore also study the effect of the identified material randomness to that of the actual material randomness for three types of structures; each with an increasing level of geometrical randomness. [less ▲]

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See detailIn CCP We Trust ... Or Do We? Assessing the Regulation of Central Clearing Counterparties in Europe
Nabilou, Hossein UL; Asimakopoulos, Ioannis UL

in Capital Markets Law Journal (2019), 14(3),

As part of financial market infrastructures, central counterparties (CCPs) have long been deemed systemically important and are likely to gain in importance due to the regulatory developments mandating ... [more ▼]

As part of financial market infrastructures, central counterparties (CCPs) have long been deemed systemically important and are likely to gain in importance due to the regulatory developments mandating central clearing for an increasing number of financial products. This paper focuses on the regulation as well as the recovery and resolution of CCPs in Europe. The existing CCP regulatory framework consists of ex-ante measures, including, among others, capital and liquidity requirements, initial and variation margins, and loss sharing mechanisms. In addition, the European proposal for the recovery and resolution of CCPs (the Proposal) contains several ex-post regulatory measures mainly in the form of rules for recovery and orderly resolution. Having studied the prudential regulatory measures for CCPs contained in the European Market Infrastructure Regulation and the ex-post recovery and resolution measures of the Proposal, this paper puts a spotlight on the specific shortcomings of the existing and proposed rules, in particular in terms of misaligned incentives, externalities, collective action problems, and certain practical impediments, and concludes that it would be misguided to inordinately rely on ex-post measures. Highlighting the limitations of the recovery and resolution mechanisms, this paper proposes that given the systemic importance of CCP functions, it is critical to improve the ex-ante measures whose objective is to prevent the failure of a CCP, rather than ex-post measures, which kick in after its failure. Accordingly, recommendations for making such improvements are proposed. [less ▲]

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See detailCraving for violence: The role of Dark Personality traits in violent video game preference
Melzer, André UL

Scientific Conference (2019, June)

Background: Violent and antisocial video games are popular, but little is known why players are drawn to these kinds of games. This present research tested whether there is a connection between player ... [more ▼]

Background: Violent and antisocial video games are popular, but little is known why players are drawn to these kinds of games. This present research tested whether there is a connection between player preferences for violent games and characteristics of so called “dark” personality traits. Method: Relying on a user-centered approach, three online studies (N=662) examined the role of “dark” personality traits together with a novel violent game preference short scale. Results: Study 1 and 2 indicated strong correlations between trait aggression and players’ interest in explicit depictions of blood and gore and games that provide experiences of domination and antisocial behavior. In Study 3, the new scale was tested together with participants’ trait aggression, trait empathy, and the Dark Triad traits of psychopathy, Machiavellianism, and narcissism. Games featuring violence and the possibility of antisocial behavior were found to meet the needs of players who lack empathy and show callous, impulsive, and exploitive (but not narcissistic) attributes. Conclusions: Findings of individual motivators for game violence significantly extend the literature that is predominantly focusing on the effects of playing these games. Apparently, game preferences and playing habits fulfill individual needs that are at least partly determined by particular, i.e. “dark”, personality characteristics. [less ▲]

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See detailReading in a new technology environment: Are reading assessments still in the ballpark?
Reichert, Monique UL; Krämer, Charlotte UL; Wollschläger, Rachel UL

Scientific Conference (2019, May 31)

Using digital technologies for daily activities such as communicating or learning has become ubiquitous today. This trend is also clearly visible within the field of reading habits, especially among ... [more ▼]

Using digital technologies for daily activities such as communicating or learning has become ubiquitous today. This trend is also clearly visible within the field of reading habits, especially among adolescents: Recent studies underline that traditional text types (e.g., fiction books) are no longer part of the more commonly read text materials (Duncan et al., 2016). The question addressed in the presentation will deal with the degree to which different reading habits impact on adolescents’ reading competence, and is intended to encourage a discussion about the construct of reading competence as generally operationalized in reading competence assessments. We base our considerations on the analyses of two data sets: The first one deals with the extra-curricular reading habits of 3074 9th grade students, and the impact of these practices on their German reading competence. The corresponding data are taken from a survey regarding their reading habits in terms of ten different types of texts (e.g., non-fiction books, e-mails). A regression analysis reveals the strongest impact on reading competence for narrative texts, whilst reading digital texts – although highly attractive among the students – is found to be of minor importance. The second data set differentiates between the reading habits of around 4500 adolescents regarding 1) traditional (printed) texts, 2) digitalised texts (e.g., e-books), and 3) text types that have emerged with new technologies (e.g., social media texts). The ensuing discussion compares particularities of classical and digital texts, and raises questions concerning the construct of reading competence (to be) targeted by standardized tests. [less ▲]

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See detailMonitoring du système scolaire – Le modèle luxembourgeois (invited talk)
Fischbach, Antoine UL

Scientific Conference (2019, May 21)

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See detailWho’s afraid of Donkey Kong? Testing the Stereotype Threat Effect in Video Gaming
Holl, Elisabeth UL; Wagener, Gary L.; Melzer, André UL

Scientific Conference (2019, May)

In two studies (Study 1: N = 130; Study 2: N = 56) participants played a video game (Bejeweled 3; SkyChasers) and were either confronted with a stereotype threat (ST) or not. ST is defined as the risk of ... [more ▼]

In two studies (Study 1: N = 130; Study 2: N = 56) participants played a video game (Bejeweled 3; SkyChasers) and were either confronted with a stereotype threat (ST) or not. ST is defined as the risk of confirming a negative stereotype about one’s own group and has been investigated in various field, i.a. in gaming. In the first study participants were confronted with the stereotype that women would perform worse in video games than men. In the second study we worked with a reversed stereotype, namely that women would have now outpaced males in some genres of video games. Our results show that performance varies across gender and genre. Although we did not find the hypothesized interaction effect of gender and ST condition in performance, self-reported measures, such as perceived frustration, and moderating variables indicate performance differences both for women and men, but on different psychological dimensions. [less ▲]

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See detailVIEW-INVARIANT ACTION RECOGNITION FROM RGB DATA VIA 3D POSE ESTIMATION
Baptista, Renato UL; Ghorbel, Enjie UL; Papadopoulos, Konstantinos UL et al

in IEEE International Conference on Acoustics, Speech and Signal Processing, Brighton, UK, 12–17 May 2019 (2019, May)

In this paper, we propose a novel view-invariant action recognition method using a single monocular RGB camera. View-invariance remains a very challenging topic in 2D action recognition due to the lack of ... [more ▼]

In this paper, we propose a novel view-invariant action recognition method using a single monocular RGB camera. View-invariance remains a very challenging topic in 2D action recognition due to the lack of 3D information in RGB images. Most successful approaches make use of the concept of knowledge transfer by projecting 3D synthetic data to multiple viewpoints. Instead of relying on knowledge transfer, we propose to augment the RGB data by a third dimension by means of 3D skeleton estimation from 2D images using a CNN-based pose estimator. In order to ensure view-invariance, a pre-processing for alignment is applied followed by data expansion as a way for denoising. Finally, a Long-Short Term Memory (LSTM) architecture is used to model the temporal dependency between skeletons. The proposed network is trained to directly recognize actions from aligned 3D skeletons. The experiments performed on the challenging Northwestern-UCLA dataset show the superiority of our approach as compared to state-of-the-art ones. [less ▲]

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See detailLearning to Sport and Refactor Inconsistent Method Names
Liu, Kui UL; Kim, Dongsun; Bissyande, Tegawendé François D Assise UL et al

in 41st ACM/IEEE International Conference on Software Engineering (ICSE) (2019, May)

To ensure code readability and facilitate software maintenance, program methods must be named properly. In particular, method names must be consistent with the corresponding method implementations ... [more ▼]

To ensure code readability and facilitate software maintenance, program methods must be named properly. In particular, method names must be consistent with the corresponding method implementations. Debugging method names remains an important topic in the literature, where various approaches analyze commonalities among method names in a large dataset to detect inconsistent method names and suggest better ones. We note that the state-of-the-art does not analyze the implemented code itself to assess consistency. We thus propose a novel automated approach to debugging method names based on the analysis of consistency between method names and method code. The approach leverages deep feature representation techniques adapted to the nature of each artifact. Experimental results on over 2.1 million Java methods show that we can achieve up to 15 percentage points improvement over the state-of-the-art, establishing a record performance of 67.9% F1-measure in identifying inconsistent method names. We further demonstrate that our approach yields up to 25% accuracy in suggesting full names, while the state-of-the-art lags far behind at 1.1% accuracy. Finally, we report on our success in fixing 66 inconsistent method names in a live study on projects in the wild. [less ▲]

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See detailBrauchen wir noch Kontinuitätenbiografien? Der Fall Franz Thedieck (1900-1995)
Brüll, Christoph UL

Presentation (2019, April 29)

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See detailYou Cannot Fix What You Cannot Find! An Investigation of Fault Localization Bias in Benchmarking Automated Program Repair Systems
Liu, Kui UL; Koyuncu, Anil UL; Bissyande, Tegawendé François D Assise UL et al

in The 12th IEEE International Conference on Software Testing, Verification and Validation (ICST-2019) (2019, April 24)

Properly benchmarking Automated Program Repair (APR) systems should contribute to the development and adoption of the research outputs by practitioners. To that end, the research community must ensure ... [more ▼]

Properly benchmarking Automated Program Repair (APR) systems should contribute to the development and adoption of the research outputs by practitioners. To that end, the research community must ensure that it reaches significant milestones by reliably comparing state-of-the-art tools for a better understanding of their strengths and weaknesses. In this work, we identify and investigate a practical bias caused by the fault localization (FL) step in a repair pipeline. We propose to highlight the different fault localization configurations used in the literature, and their impact on APR systems when applied to the Defects4J benchmark. Then, we explore the performance variations that can be achieved by "tweaking'' the FL step. Eventually, we expect to create a new momentum for (1) full disclosure of APR experimental procedures with respect to FL, (2) realistic expectations of repairing bugs in Defects4J, as well as (3) reliable performance comparison among the state-of-the-art APR systems, and against the baseline performance results of our thoroughly assessed kPAR repair tool. Our main findings include: (a) only a subset of Defects4J bugs can be currently localized by commonly-used FL techniques; (b) current practice of comparing state-of-the-art APR systems (i.e., counting the number of fixed bugs) is potentially misleading due to the bias of FL configurations; and (c) APR authors do not properly qualify their performance achievement with respect to the different tuning parameters implemented in APR systems. [less ▲]

Detailed reference viewed: 84 (10 UL)