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See detailIntegrating Topological Proofs with Model Checking to Instrument Iterative Design
Menghi, Claudio UL; Rizzi, Alessandro Maria; Bernasconi, Anna

in Proceedings of the 23rd International Conference on Fundamental Approaches to Software Engineering, FASE 2020 (2020)

System development is not a linear, one-shot process. It proceeds through refinements and revisions. To support assurance that the system satisfies its requirements, it is desirable that continuous ... [more ▼]

System development is not a linear, one-shot process. It proceeds through refinements and revisions. To support assurance that the system satisfies its requirements, it is desirable that continuous verification can be performed after each refinement or revision step. To achieve practical adoption, formal verification must accommodate continuous verification efficiently and effectively. Model checking provides developers with information useful to improve their models only when a property is not satisfied, i.e., when a counterexample is returned. However, it is desirable to have some useful information also when a property is instead satisfied. To address this problem we propose TOrPEDO, an approach that supports verification in two complementary forms: model checking and proofs. While model checking is typically used to pinpoint model behaviors that violate requirements, proofs can instead explain why requirements are satisfied. In our work, we introduce a specific notion of proof, called Topological Proof. A topological proof produces a slice of the original model that justifies the property satisfaction. Because models can be incomplete, TOrPEDO supports reasoning on requirements satisfaction, violation, and possible satisfaction (in the case where satisfaction depends on unknown parts of the model). Evaluation is performed by checking how topological proofs support software development on 12 modeling scenarios and 15 different properties obtained from 3 examples from literature. Results show that: (i) topological proofs are ≈60% smaller than the original models; (ii) after a revision, in ≈78% of cases, the property can be re-verified by relying on a simple syntactic check. [less ▲]

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See detailCross-border everyday lives on the Luxembourg border? An empirical approach: the example of cross-border commuters and residential migrants
Wille, Christian UL; Roos, Ursula

in Wille, Christian; Nienaber, Birte (Eds.) Border Experiences in Europe. Everyday Life - Working Life - Communication - Languages (2020)

Luxembourg is characterized by phenomena of mobility that includecross-border commuters and residential migrants. While both groups havebeen mainly examined from a socioeconomic perspective, this ... [more ▼]

Luxembourg is characterized by phenomena of mobility that includecross-border commuters and residential migrants. While both groups havebeen mainly examined from a socioeconomic perspective, this paperadopts a sociocultural approach. We will focus on the question of the ex-tent to which cross-border mobility in everyday life promotes cross-borderlifeworlds. This will involve examining people’s social contacts at theirplace of work and/or place of residence as well as the spatial organizationof practices of the everyday life of both groups. The paper gives insights in-to everyday lives at the EU’s internal borders, whose organization into na-tion states is subordinate and at the same time constitutive. [less ▲]

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See detailHeart and brain: cortical representation of cardiac signals is disturbed in borderline personality disorder, but unaffected by oxytocin administration
Schmitz, M.; Müller, L. E.; Schulz, André UL et al

in Journal of Affective Disorders (2020), 264(1), 24-28

Background: Emotional dysregulation, a core feature of borderline personality disorder (BPD) has recently been linked to deficits in the cortical representation of bodily signals. Oxytocin modulates the ... [more ▼]

Background: Emotional dysregulation, a core feature of borderline personality disorder (BPD) has recently been linked to deficits in the cortical representation of bodily signals. Oxytocin modulates the salience of external social cues. However, its role in interoception is still not fully understood. The aim of the current study was to replicate reduced heartbeatevoked potentials (HEPs) as a marker for the cortical representation of cardiac signals in BPD and to explore potential effects of oxytocin on HEP amplitude. Methods: Fifty-three medication-free women with a DSM-IV diagnosis of BPD and sixty healthy female controls (HCs) participated in the study. In a randomized, double-blind placebo-controlled trial, participants self-administered either 24 I.U. of oxytocin or placebo and took part in a 5-minute resting-state electrocardiogram (ECG) with parallel electroencephalogram (EEG) measurement. In addition, emotional dysregulation and BPD symptomatology were assessed with self-report questionnaires. Results: Patients with BPD had significantly lower mean HEP amplitudes than HCs. Furthermore, HEP amplitudes were negatively correlated with emotional dysregulation in the whole sample. However, oxytocin had no significant effect on HEP amplitude. Limitations: Only female participants were investigated and no clinicial controls were included. Conclusions: This is the first replication from an independent sample showing a reduced cortical representation of cardiac signals in BPD patients. This, together with other bodyrelated symptoms, suggests deficits in the processing of bodily signals, which seem to be associated with emotional dysregulation. Whether oxytocin influences HEP during emotion regulation tasks needs to be investigated in future studies. [less ▲]

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See detailBrentanos Klingding. Eine Kulturpolitik der Buchstäblichkeit in der Romantik
Dembeck, Till UL

in Geisenhanslüke, Achim (Ed.) Buchstäblichkeit (2020)

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See detailCortisol rapidly increases baroreflex sensitivity of heart rate control, but does not affect cardiac modulation of startle
Schulz, André UL; Richter, Steffen; Ferreira de Sá, Diana S. et al

in Physiology and Behavior (2020), 215(1), 112792

Cortisol, the final product of human HPA axis activation, rapidly modulates the cortical processing of afferent signals originating from the cardiovascular system. While peripheral effects have been ... [more ▼]

Cortisol, the final product of human HPA axis activation, rapidly modulates the cortical processing of afferent signals originating from the cardiovascular system. While peripheral effects have been excluded, it remains unclear whether this effect is mediated by cortical or subcortical (e.g. brainstem) CNS mechanisms. Cardiac modulation of startle (CMS) has been proposed as a method to reflect cardio-afferent signals at subcortical (potentially brainstem-) level. Using a single blind, randomized controlled design, the cortisol group (n = 16 volunteers) received 1 mg cortisol intravenously, while the control group (n = 16) received a placebo substance. The CMS procedure involved the assessment of eye blink responses to acoustic startle stimuli elicited at six different latencies to ECG-recorded R-waves (R + 0, 100, 200, 300, 400 and 500 ms). CMS was assessed at four measurement points: baseline, -16 min, +0 min, and +16 min relative to substance application. Baroreflex sensitivity (BRS) of heart rate (HR) control was measured non-invasively based on spontaneous beat-to-beat HR and systolic blood pressure changes. In the cortisol group, salivary cortisol concentration increased after IV cortisol administration, indicating effective distribution of the substance throughout the body. Furthermore, BRS increased in the cortisol group after cortisol infusion. There was no effect of cortisol on the CMS effect, however. These results suggest that low doses of cortisol do not affect baro-afferent signals, but central or efferent components of the arterial baroreflex circuit presumably via rapid, non-genomic mechanisms. [less ▲]

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See detailUnderstanding Walking Meetings: Drivers and Barriers
Damen, Ida; Lallemand, Carine UL; Brankaert, Rens et al

Scientific Conference (2020)

There is increased interest in reducing sedentary behavior of office workers to combat the negative health effects of prolonged sitting. Walking meetings offer a promising solution to this problem as they ... [more ▼]

There is increased interest in reducing sedentary behavior of office workers to combat the negative health effects of prolonged sitting. Walking meetings offer a promising solution to this problem as they facilitate a physically active way of working. To inform future development of technologies supporting these type of meetings, in-depth qualitative insights into people’s experiences of walking meetings are needed. We conducted semi-structured walking interviews (N=16) to identify key drivers and barriers for walking meetings in a living lab setting by using the ‘WorkWalk’. The ‘WorkWalk’ is a 1.8 km walking route indicated by a dotted blue line with outdoor meeting points, integrated into the room booking system. Our findings provide insights into how walking meetings are experienced and affect the set-up and social dynamics of meetings. We propose design recommendations for the development of future technologies and service design elements to support walking meetings and active ways of working. [less ▲]

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See detailMeeting Designers Where They Are: Using Industry Events as a Research Venue for HCI and Design Methods Development
Lockton, Dan; Lallemand, Carine UL

Scientific Conference (2020)

There is much work in the CHI community about the ‘industry-academia divide’, and how to bridge it. One key crossover between HCI/UX scientists and practitioners is the development and use of tools and ... [more ▼]

There is much work in the CHI community about the ‘industry-academia divide’, and how to bridge it. One key crossover between HCI/UX scientists and practitioners is the development and use of tools and methods—boundary objects between academia and practice. Among other forms of collaboration, there is an underdeveloped opportunity for academics to make use of industry events (conferences, meetups, design jams) as a research venue in the context of tool and method development. This paper describes three cases from work in academia-industry engagement over the last decade, in which workshops or experiments have been run at industry events as a way of trialling and developing tools directly with practitioners. We discuss advantages of this approach and extract key insights and practical implications, highlighting how the CHI community might use this method more widely, gathering relevant research outcomes while contributing to knowledge exchange between academia and practice. [less ▲]

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See detailInterference Exploitation via Symbol-Level Precoding: Overview, State-of-the-Art and Future Directions
Li, Ang; Spano, Danilo UL; Krivochiza, Jevgenij UL et al

in IEEE Communications Surveys and Tutorials (2020)

Interference is traditionally viewed as a performance limiting factor in wireless communication systems, which is to be minimized or mitigated. Nevertheless, a recent line of work has shown that by ... [more ▼]

Interference is traditionally viewed as a performance limiting factor in wireless communication systems, which is to be minimized or mitigated. Nevertheless, a recent line of work has shown that by manipulating the interfering signals such that they add up constructively at the receiver side, known interference can be made beneficial and further improve the system performance in a variety of wireless scenarios, achieved by symbol-level precoding (SLP). This paper aims to provide a tutorial on interference exploitation techniques from the perspective of precoding design in a multi-antenna wireless communication system, by beginning with the classification of constructive interference (CI) and destructive interference (DI). The definition for CI is presented and the corresponding mathematical characterization is formulated for popular modulation types, based on which optimization-based precoding techniques are discussed. In addition, the extension of CI precoding to other application scenarios as well as for hardware efficiency is also described. Proof-of-concept testbeds are demonstrated for the potential practical implementation of CI precoding, and finally a list of open problems and practical challenges are presented to inspire and motivate further research directions in this area. [less ▲]

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See detailDomain-specific views on aging and preparation for age-related changes – Development and validation of three brief scales.
Kornadt, Anna Elena UL; Hess, Thomas M; Rothermund, Klaus

in Journals of Gerontology. Series B, Psychological Sciences and Social Sciences (2020), 75(2), 303-307

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See detailComparative Education in an Age of Competition and Collaboration
Powell, Justin J W UL

in Comparative Education (2020), 56

Comparative education relies on experiences, expertise, data, and criticism derived from multiple contexts and diverse levels to generate insights, facilitate understanding, and explain change. Marked by ... [more ▼]

Comparative education relies on experiences, expertise, data, and criticism derived from multiple contexts and diverse levels to generate insights, facilitate understanding, and explain change. Marked by connectivity, our contemporary era vastly increases the (potential) diffusion of ideas essential for scientific advance. Three interlocking trends emphasise the growing relevance of comparative educational research. Firstly, competition has become more potent – among scholars, their organisations, and within as across countries. Secondly, educational studies, as science more generally, are increasingly conducted in collaboration – across disciplinary, cultural, linguistic, and organisational boundaries – enhancing the potential for discovery while producing influential scholarship. Thirdly, while educational research and policymaking are increasingly comparative, comparative knowledge stores are often only selectively used. To counter such reductionism, in-depth comparative institutional analyses across divides of academy, policymaking, and practice remain crucial. The multidisciplinary field must claim its relevance more persuasively, even as scholarly exchange, mobilities, and cultural knowledge endure as vital foundations. [less ▲]

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See detailLämdliche Räume Europas
Nienaber, Birte UL

in Gebhardt, Hans; Glaser, Rüdiger; Radtke, Ulrich (Eds.) et al Geographie - Physische Geographie und Humangeographie (2020)

The chapter of a university textbook explains the diversity of European rural areas and their development.

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See detailEffects of rejection intensity and rejection sensitivity on social approach behavior in women
Schaan, Violetta; Schulz, André UL; Bernstein, Michael et al

in PLoS ONE (2020), 15(1), 0227799

Objective: Perceived rejection plays an important role for mental health and social integration. This study investigated the impact of rejection intensity and rejection sensitivity on social approach ... [more ▼]

Objective: Perceived rejection plays an important role for mental health and social integration. This study investigated the impact of rejection intensity and rejection sensitivity on social approach behavior. Method: 121 female participants were randomly assigned to one of three conditions differing in the degree of induced rejection (inclusion, medium rejection, severe rejection). Thereafter they were asked to interact with an unknown person during a touch-based cooperative task. Results: Participants high in rejection sensitivity sought significantly less physical contact than participants low in rejection sensitivity. Individuals in the medium rejection condition touched their partners more often than those in the included condition, while no difference between included and severely rejected participants could be observed. Conclusions: The results suggest that the intensity of rejection matters with regard to coping. While participants in the medium intensity rejection condition aimed to ‘repair’ their social self by seeking increased contact with others, severely rejected participants did not adapt their behavior compared to included participants. Implications for therapy are discussed. [less ▲]

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See detailIllyrer und Dakerrezeption in Albanien und Rumänien. Mythenbildung und faktische Probleme.
Mersch, Sam UL

in Maner, Hans-Christian; Zelepos, Ioannis (Eds.) Antike und Byzanz als historisches Erbe in Südosteuropa (19.-21. Jahrhundert). (2020)

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See detailMoving from nation into region. Experiences and memories of cross-border dwelling in the Greater Region SaarLorLux
Boesen, Elisabeth UL

in Wille, Christian; Nienaber, Birte (Eds.) Border Experiences in Europe. Everyday Life - Working Life - Communication – Languages (2020)

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See detailAutomatic Testing and Improvement of Machine Translation
Sun, Zeyu; Zhang, Jie; Harman, Mark et al

in International Conference on Software Engineering (ICSE) (2020)

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See detailGrammatische Strukturen im mehrsprachigen Kontext sichtbar und begreifbar machen: Vorstellung des grammatikdidaktischen Materials Bausteng Grammatik – Bausteine Grammatik
Weth, Constanze UL

in Langlotz, Miriam (Ed.) Grammatikdidaktik – theoretische und empirische Zugänge zu sprachlicher Heterogenität (2020)

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See detailMarkov Chain Monte Carlo and the Application to Geodetic Time Series Analysis
Olivares Pulido, German UL; Teferle, Felix Norman UL; Hunegnaw, Addisu UL

in Montillet, Jean-Philippe; Bos, Machiel (Eds.) Geodetic Time Series Analysis in Earth Sciences (2020)

The time evolution of geophysical phenomena can be characterised by stochastic time series. The stochastic nature of the signal stems from the geophysical phenomena involved and any noise, which may be ... [more ▼]

The time evolution of geophysical phenomena can be characterised by stochastic time series. The stochastic nature of the signal stems from the geophysical phenomena involved and any noise, which may be due to, e.g., un-modelled effects or measurement errors. Until the 1990's, it was usually assumed that white noise could fully characterise this noise. However, this was demonstrated to be not the case and it was proven that this assumption leads to underestimated uncertainties of the geophysical parameters inferred from the geodetic time series. Therefore, in order to fully quantify all the uncertainties as robustly as possible, it is imperative to estimate not only the deterministic but also the stochastic parameters of the time series. In this regard, the Markov Chain Monte Carlo (MCMC) method can provide a sample of the distribution function of all parameters, including those regarding the noise, e.g., spectral index and amplitudes. After presenting the MCMC method and its implementation in our MCMC software we apply it to synthetic and real time series and perform a cross-evaluation using Maximum Likelihood Estimation (MLE) as implemented in the CATS software. Several examples as to how the MCMC method performs as a parameter estimation method for geodetic time series are given in this chapter. These include the applications to GPS position time series, superconducting gravity time series and monthly mean sea level (MSL) records, which all show very different stochastic properties. The impact of the estimated parameter uncertainties on sub-sequentially derived products is briefly demonstrated for the case of plate motion models. Finally, the MCMC results for weekly downsampled versions of the benchmark synthetic GNSS time series as provided in Chapter 2 are presented separately in an appendix. [less ▲]

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See detailEvaluation of reverse osmosis drinking water treatment of riverbank filtrate using bioanalytical tools and non-target screening
Albergamo, Vittorio; Escher, Beate I.; Schymanski, Emma UL et al

in Environmental Science: Water Research Technology (2020), 6(1), 103--116

Stand-alone reverse osmosis (RO) has been proposed to produce high-quality drinking water from raw riverbank filtrate impacted by anthropogenic activities. To evaluate RO efficacy in removing organic ... [more ▼]

Stand-alone reverse osmosis (RO) has been proposed to produce high-quality drinking water from raw riverbank filtrate impacted by anthropogenic activities. To evaluate RO efficacy in removing organic micropollutants, biological analyses were combined with non-target screening using high-resolution mass spectrometry and open cheminformatics tools. The bank filtrate induced xenobiotic metabolism mediated by the aryl hydrocarbon receptor AhR, adaptive stress response mediated by the transcription factor Nrf2 and genotoxicity in the Ames-fluctuation test. These effects were absent in the RO permeate (product water), indicating the removal of bioactive micropollutants by RO membranes. In the water samples, 49 potentially toxic compounds were tentatively identified with the in silico fragmentation tool MetFrag using the US Environmental Protection Agency CompTox Chemicals Dashboard database. 5 compounds were confirmed with reference standards and 16 were tentatively identified with high confidence based on similarities to accurate mass spectra in open libraries. The bioactivity data of the confirmed chemicals indicated that 2,6-dichlorobenzamide and bentazone in water samples can contribute to the activation of AhR and oxidative stress response, respectively. The bioactivity data of 7 compounds tentatively identified with high confidence indicated that these structures can contribute to the induction of such effects. This study showed that riverbank filtration followed by RO could produce drinking water free of the investigated toxic effects. [less ▲]

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See detailA Real-Time Approach for Chance-Constrained Motion Planning with Dynamic Obstacles
Castillo Lopez, Manuel UL; Ludivig, Philippe; Sajadi-Alamdari, Seyed Amin et al

in IEEE Robotics and Automation Letters (RA-L) (2020)

Uncertain dynamic obstacles, such as pedestrians or vehicles, pose a major challenge for optimal robot navigation with safety guarantees. Previous work on motion planning has followed two main strategies ... [more ▼]

Uncertain dynamic obstacles, such as pedestrians or vehicles, pose a major challenge for optimal robot navigation with safety guarantees. Previous work on motion planning has followed two main strategies to provide a safe bound on an obstacle's space: a polyhedron, such as a cuboid, or a nonlinear differentiable surface, such as an ellipsoid. The former approach relies on disjunctive programming, which has a relatively high computational cost that grows exponentially with the number of obstacles. The latter approach needs to be linearized locally to find a tractable evaluation of the chance constraints, which dramatically reduces the remaining free space and leads to over-conservative trajectories or even unfeasibility. In this work, we present a hybrid approach that eludes the pitfalls of both strategies while maintaining the original safety guarantees. The key idea consists in obtaining a safe differentiable approximation for the disjunctive chance constraints bounding the obstacles. The resulting nonlinear optimization problem is free of chance constraint linearization and disjunctive programming, and therefore, it can be efficiently solved to meet fast real-time requirements with multiple obstacles. We validate our approach through mathematical proof, simulation and real experiments with an aerial robot using nonlinear model predictive control to avoid pedestrians. [less ▲]

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