Emergent Leadership Detection Across Datasets

Automatic detection of emergent leaders in small groups from nonverbal behaviour is a growing research topic in social signal processing but existing methods were evaluated on single datasets -- an unrealistic assumption for real-world applications in which systems are required to also work in settings unseen at training time. It therefore remains unclear whether current methods for emergent leadership detection generalise to similar but new settings and to which extent. To overcome this limitation, we are the first to study a cross-dataset evaluation setting for the emergent leadership detection task. We provide evaluations for within- and cross-dataset prediction using two current datasets (PAVIS and MPIIGroupInteraction), as well as an investigation on the robustness of commonly used feature channels (visual focus of attention, body pose, facial action units, speaking activity) and online prediction in the cross-dataset setting. Our evaluations show that using pose and eye contact based features, cross-dataset prediction is possible with an accuracy of 0.68, as such providing another important piece of the puzzle towards emergent leadership detection in the real world.Comment: 5 pages, 3 figure

Design and Construction of Large Size Micromegas Chambers for the Upgrade of the ATLAS Muon Spectrometer

Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about $\mathbf{150~m^2}$ of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each layer covers more than $\mathbf{2~m^2}$ for a total active area of $\mathbf{1200~m^2}$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15$\mathbf{\%}$ transverse momentum resolution for $\mathbf{1~TeV}$ muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as $\mathbf{30~\mu m}$ along the precision coordinate and $\mathbf{80~\mu m}$ perpendicular to the chamber. The design and construction procedure of the Micromegas modules will be presented, as well as the design for the assembly of modules onto the New Small Wheel. Emphasis will be on the methods developed to achieve the challenging mechanical precision. Measurements and simulations of deformations created on chamber prototypes as a function of thermal gradients, internal stress (mesh tension and module fixation on supports) and gas over-pressure were essential in the development of the final design. During installation and operation all deformations and relative misalignments will be monitored by an optical alignment system and compensated in the tracking software

Interacting hard rods on a lattice: Distribution of microstates and density functionals

We derive exact density functionals for systems of hard rods with first-neighbor interactions of arbitrary shape but limited range on a one-dimensional lattice. The size of all rods is the same integer unit of the lattice constant. The derivation, constructed from conditional probabilities in a Markov chain approach, yields the exact joint probability distribution for the positions of the rods as a functional of their density profile. For contact interaction ("sticky core model") between rods we give a lattice fundamental measure form of the density functional and present explicit results for contact correlators, entropy, free energy, and chemical potential. Our treatment includes inhomogeneous couplings and external potentials.Comment: 8 pages, 5 figure

Detecting Low Rapport During Natural Interactions in Small Groups from Non-Verbal Behaviour

Rapport, the close and harmonious relationship in which interaction partners are "in sync" with each other, was shown to result in smoother social interactions, improved collaboration, and improved interpersonal outcomes. In this work, we are first to investigate automatic prediction of low rapport during natural interactions within small groups. This task is challenging given that rapport only manifests in subtle non-verbal signals that are, in addition, subject to influences of group dynamics as well as inter-personal idiosyncrasies. We record videos of unscripted discussions of three to four people using a multi-view camera system and microphones. We analyse a rich set of non-verbal signals for rapport detection, namely facial expressions, hand motion, gaze, speaker turns, and speech prosody. Using facial features, we can detect low rapport with an average precision of 0.7 (chance level at 0.25), while incorporating prior knowledge of participants' personalities can even achieve early prediction without a drop in performance. We further provide a detailed analysis of different feature sets and the amount of information contained in different temporal segments of the interactions.Comment: 12 pages, 6 figure

The Optimality of Simple Contracts: Moral Hazard and Loss Aversion

This paper extends the standard principal-agent model with moral hazard to allow for agents having reference- dependent preferences according to Köszegi and Rabin (2006, 2007). The main finding is that loss aversion leads to fairly simple contracts. In particular, when shifting the focus from standard risk aversion to loss aversion, the optimal contract is a simple bonus contract, i.e. when the agent's performance exceeds a certain threshold he receives a fixed bonus payment. Moreover, if the agent is sufficiently loss averse, it is shown that the first-order approach is not necessarily valid. If this is the case the principal may be unable to fine-tune incentives. Strategic ignorance of information by the principal, however, allows to overcome these problems and may even reduce the cost of implementation.Agency Model; Moral Hazard; Reference-Dependent Preferences; Loss Aversion

Monodisperse hard rods in external potentials

We consider linear arrays of cells of volume $V_\mathrm{c}$ populated by monodisperse rods of size $\sigma V_\mathrm{c}$, $\sigma=1,2,\ldots$, subject to hardcore exclusion interaction. Each rod experiences a position-dependent external potential. In one application we also examine effects of contact forces between rods. We employ two distinct methods of exact analysis with complementary strengths and different limits of spatial resolution to calculate profiles of pressure and density on mesoscopic and microscopic length scales at thermal equilibrium. One method uses density functionals and the other statistically interacting vacancy particles. The applications worked out include gravity, power-law traps, and hard walls. We identify oscillations in the profiles on a microscopic length scale and show how they are systematically averaged out on a well-defined mesoscopic length scale to establish full consistency between the two approaches. The continuum limit, realized as $V_\mathrm{c}\to0$, $\sigma\to\infty$ at nonzero and finite $\sigma V_\mathrm{c}$, connects our highest-resolution results with known exact results for monodisperse rods in a continuum. We also compare the pressure profiles obtained from density functionals with the average microscopic pressure profiles derived from the pair distribution function.Comment: 17 pages, 14 figure

Elder (Sace), Murder Scenes. Normality, Deviance, and Criminal Violence in Weimar Berlin

In her book Murder Scenes, Sace Elder assigns herself the task of investigating how murder was experienced by Berliners during the Weimar period, and how it was understood in the city as an urban phenomenon. Elder is interested in how the inhabitants of Berlin made sense of homicidal violence. Certainly, the killing of a fellow citizen is the most serious breach of the rules of a community : not only are such rules broken, but they are also undermined, and threatening the community as a whole..