Impact Of Content Features For Automatic Online Abuse Detection

Online communities have gained considerable importance in recent years due to the increasing number of people connected to the Internet. Moderating user content in online communities is mainly performed manually, and reducing the workload through automatic methods is of great financial interest for community maintainers. Often, the industry uses basic approaches such as bad words filtering and regular expression matching to assist the moderators. In this article, we consider the task of automatically determining if a message is abusive. This task is complex since messages are written in a non-standardized way, including spelling errors, abbreviations, community-specific codes... First, we evaluate the system that we propose using standard features of online messages. Then, we evaluate the impact of the addition of pre-processing strategies, as well as original specific features developed for the community of an online in-browser strategy game. We finally propose to analyze the usefulness of this wide range of features using feature selection. This work can lead to two possible applications: 1) automatically flag potentially abusive messages to draw the moderator's attention on a narrow subset of messages ; and 2) fully automate the moderation process by deciding whether a message is abusive without any human intervention

The growth of a Super Stable Heap : an experimental and numerical study

We report experimental and numerical results on the growth of a super stable heap (SSH). Such a regime appears for flows in a thin channel and for high flow rate : the flow occurs atop a nearly static heap whose angle is stabilized by the flowing layer at its top and the side wall friction. The growth of the static heap is investigated in this paper. A theoretical analysis inspired by the BRCE formalism predicts the evolution of the growth process, which is confirmed by both experiments and numerical simulations. The model allows us to link the characteristic time of the growth to the exchange rate between the "moving" and "static" grains. We show that this rate is proportional to the height of the flowing layer even for thick flows. The study of upstream traveling waves sheds new light on the BCRE model

Coordination and Cooperation in Investment Timing with Externalities ?

We characterize sequential (preemption) and simultaneous (coordination) equilibria, as well as joint-value maximizing (cooperation) solutions, in a model of investment timing allowing for externalities in both flow pro...ts and investment costs. For two ex-ante symmetric ...rms, either preemption or attrition occur depending on the size of the investment externality. Coordination is less likely with more discounting, as in a repeated game, and more likely with higher growth and volatility. Optimal cooperation involves either monopoly or duopoly investment, the latter being either symmetric or asymmetric. Finally, these characterizations are validated by applications to standard speci...cations of capacity accumulation and of R&D investment. In the former setup, coordination is likelier if installed capacities and lumpy investments are both large. With R&D input choices, if investment synergies are large, coordination and cooperation result in the same outcomes.Investment Timing; Real Options; Simultaneous Equilibrium; Joint-Value Maximization; Cooperation; Investment Externalities

La technique du bi-maillage appliquée au formage incrémental

National audienceDans ce texte nous présentons l'application de la technique du bi-maillage à la simulation de procédés de mise en forme incrémentale à froid. Après une comparaison de la méthode avec des techniques plus traditionnelles sur un cas académique, nous présenterons des résultats sur un cas plus complexe