q-Breathers in Discrete Nonlinear Schroedinger arrays with weak disorder

Nonlinearity and disorder are key players in vibrational lattice dynamics, responsible for localization and delocalization phenomena. $q$-Breathers -- periodic orbits in nonlinear lattices, exponentially localized in the reciprocal linear mode space -- is a fundamental class of nonlinear oscillatory modes, currently found in disorder-free systems. In this paper we generalize the concept of $q$-breathers to the case of weak disorder, taking the Discrete Nonlinear Schr\"{o}dinger chain as an example. We show that $q$-breathers retain exponential localization near the central mode, provided that disorder is sufficiently small. We analyze statistical properties of the instability threshold and uncover its sensitive dependence on a particular realization. Remarkably, the threshold can be intentionally increased or decreased by specifically arranged inhomogeneities. This effect allows us to formulate an approach to controlling the energy flow between the modes. The relevance to other model arrays and experiments with miniature mechanical lattices, light and matter waves propagation in optical potentials is discussed.Comment: 5 pages, 3 figure

Improving the Efficiency of Reasoning Through Structure-Based Reformulation

Abstract. We investigate the possibility of improving the efficiency of reasoning through structure-based partitioning of logical theories, combined with partitionbased logical reasoning strategies. To this end, we provide algorithms for reasoning with partitions of axioms in first-order and propositional logic. We analyze the computational benefit of our algorithms and detect those parameters of a partitioning that influence the efficiency of computation. These parameters are the number of symbols shared by a pair of partitions, the size of each partition, and the topology of the partitioning. Finally, we provide a greedy algorithm that automatically reformulates a given theory into partitions, exploiting the parameters that influence the efficiency of computation.

Geometric deep learning

The goal of these course notes is to describe the main mathematical ideas behind geometric deep learning and to provide implementation details for several applications in shape analysis and synthesis, computer vision and computer graphics. The text in the course materials is primarily based on previously published work. With these notes we gather and provide a clear picture of the key concepts and techniques that fall under the umbrella of geometric deep learning, and illustrate the applications they enable. We also aim to provide practical implementation details for the methods presented in these works, as well as suggest further readings and extensions of these ideas

Managing Decision Tasks and Events in Time-Aware Business Process Models

Time-aware business process models capture processes where temporal properties and constraints have to be suitably managed to achieve proper completion. Temporal aspects also constrain how decisions are made in processes: while some constraints hold only along certain paths, decision outcomes may be restricted to satisfy temporal constraints. In this paper, we present time-aware BPMN processes and discuss how to: (i) add temporal features to process elements, by considering also the impact of events on temporal constraint management; (ii) characterize decisions based on when they are made and used within a process; (iii) specify and use two novel kinds of decisions based on how their outcomes are managed; (iv) deal with intertwined temporal and decision aspects of time-aware BPMN processes to ensure proper execution

Strategic directions in constraint programming

An abstract is not available

Gender Pay Gaps in the Former Soviet Union: A Review of the Evidence

The goal of this paper is to examine the patterns and movements of the gender pay gaps in the countries of the former Soviet Union (FSU) and to place them in the context of advanced economies. We survey over 30 publications and conduct a meta-analysis of this literature. Gender pay gaps in the region are considerable and above the levels observed in advanced economies. Similar to advanced economies, industrial and occupational segregation widens the gaps in the FSU countries, whereas gender differences in educational attainment tend to shrink them. However, a much higher proportion of the gaps remain unexplained, pointing toward the role of unobserved gender differences related to actual and perceived productivity. Over the last 25 years, the gaps contracted in most FSU countries, primarily due to the reduction in the unexplained portion. Underlying the contraction at the mean are different movements in the gap across the pay distribution. Although the glass-ceiling effect has diminished in some FSU countries, it has persisted in others. We investigate the reasons underlying these findings and argue that the developments in the FSU region shed new light on our understanding of the gender pay gaps

Social Media, Gender and the Mediatisation of War: Exploring the German Armed Forces’ Visual Representation of the Afghanistan Operation on Facebook

Studies on the mediatisation of war point to attempts of governments to regulate the visual perspective of their involvements in armed conflict – the most notable example being the practice of ‘embedded reporting’ in Iraq and Afghanistan. This paper focuses on a different strategy of visual meaning-making, namely, the publication of images on social media by armed forces themselves. Specifically, we argue that the mediatisation of war literature could profit from an increased engagement with feminist research, both within Critical Security/Critical Military Studies and within Science and Technology Studies that highlight the close connection between masculinity, technology and control. The article examines the German military mission in Afghanistan as represented on the German armed forces’ official Facebook page. Germany constitutes an interesting, and largely neglected, case for the growing literature on the mediatisation of war: its strong antimilitarist political culture makes the representation of war particularly delicate. The paper examines specific representational patterns of Germany’s involvement in Afghanistan and discusses the implications which arise from what is placed inside the frame of visibility and what remains out of its view