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

Abusive Language Detection in Online Conversations by Combining Content-and Graph-based Features

In recent years, online social networks have allowed worldwide users to meet and discuss. As guarantors of these communities, the administrators of these platforms must prevent users from adopting inappropriate behaviors. This verification task, mainly done by humans, is more and more difficult due to the ever growing amount of messages to check. Methods have been proposed to automatize this moderation process, mainly by providing approaches based on the textual content of the exchanged messages. Recent work has also shown that characteristics derived from the structure of conversations, in the form of conversational graphs, can help detecting these abusive messages. In this paper, we propose to take advantage of both sources of information by proposing fusion methods integrating content-and graph-based features. Our experiments on raw chat logs show that the content of the messages, but also of their dynamics within a conversation contain partially complementary information, allowing performance improvements on an abusive message classification task with a final F-measure of 93.26%

Impact of Suction and Injection Gas Superheat Degrees on The Performance of a Residential Heat Pump With Vapor Injection and Variable Speed Scroll Compressor

The market share of heat pump systems has grown significantly in Europe in the past decades and, in residential applications, air-source heat pumps (ASHP) are usually considered due to their relatively low cost. In the literature, it has been widely demonstrated that injection cycle can improve the system performance and operating range. This paper presents experimental results of an air-to-water residential heat pump using a variable speed scroll compressor with vapor injection. The first part of the paper focuses on the experimental results collected from a vapor injection and variable speed scroll compressor air-to-water residential heat pump. The unit is a 10 kW residential system working with R410a as working fluid and capable of providing floor heating and domestic hot water. It was tested in a controlled environment in order to achieve a wide range of outdoor and indoor conditions. The impact on the system performance of the vapor superheat degrees at both injection and suction ports is discussed. It is shown that a better control of these variables could improve the system COP and heating capacity by respectively 10 and 15%. It is also shown that the control of the superheat degrees is a coupled problem and the use of standard gain-scheduled SISO PIDs is not optimal. The second part of this paper presents a model of the system. Finite-volume models are used for the heat exchangers and the split lines. A thermodynamic model of the vapor injection scroll compressor is developed using empirical correlations for the volumetric efficiency, isentropic efficiency and the ratio between the injection and suction mass flow rates. A simple model is proposed for the four-way valve. Finally, a static decoupler-based controller is presented in order to take into account the coupling between both superheat degrees and shows increased performances compared to the SISO PID controller

Etudes des procédés d'encapsulation hermétique au niveau du substrat par la technologie de transfert de films

Les micro-dispositifs comportant des structures libérées et mobiles sont d une part très sensibles aux variations de leur environnement de travail, et d autre part très fragiles mécaniquement. L étape de découpe du substrat en plusieurs puces est extrêmement agressive et peut entrainer la destruction totale des micro-dispositifs. L encapsulation avant la découpe va alors prémunir les micro-composants lors de cette étape critique et continuer à garantir leur bon fonctionnement tout au long de leur utilisation en conservant la stabilité et la fiabilité de leur performance. Le conditionnement doit en outre interfacer les micro-dispositifs encapsulés avec le monde macroscopique en vue de leur utilisation. De nombreux procédés de fabrication ont déjà été développés pour l élaboration d un conditionnement. C est le cas de l encapsulation puce par puce, substrat - substrat, par couche sacrificielle par exemple. Ils sont toutefois très contraignants (encombrement, compatibilité, coût, ). Nous avons étudié, au cours de cette thèse, un procédé innovant de conditionnement hermétique par transfert de film utilisant une couche à adhésion contrôlée. Cette technologie consiste à élaborer des capots protecteurs sur le substrat moule puis à les reporter collectivement pour encapsuler les micro-dispositifs. Ce procédé est totalement compatible avec un interfaçage électrique de composant qui traverse les cordons de scellement ou le capot. Ce procédé nécessite la maîtrise de la croissance de divers films (C, CxFy, Ni, AlN, parylène, BCB, Au-In) et permet d obtenir des boitiers étanches, hermétiques et robustes qui devraient très rapidement pouvoir être utilisés pour le conditionnement de MEMS.Micro-devices which are composed of free standing or mobile structures are very sensitive to the working condition and mechanically very fragile. The saw dicing steps is very aggressive and it can destroy the micro-devices. Packaging will prevent the micro devices from any damage during this critical step and also take care of it all along its life by controlling its performance stability and reliability. Moreover, the suited devices use needs a connection to the macroscopic word through the packaging. Many packaging process flow has already developed such as pick and place, wafer to wafer, thin film packaging with a sacrificial layer. Nevertheless, they have got many drawbacks (footprint, process compatibility, cost ). We have developed an attractive wafer level hermetic packaging process by film transfer technology during this these. It relies on a transferred molded film cap from a carrier wafer to the donor wafer. Electrical path can be done through the cap or the bonding ring. Cap manufacturing need a high layer growth skill for example in C, CxFy, Ni, AlN, parylène, BCB, Au-In films to make robust, hermetic encapsulation which should be soon used for MEMS packaging.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Hybrid Stereocorrelation Using Infrared and Visible Light Cameras

International audience3D kinematic fields are measured using an original stereovision system composed of one infrared (IR) and one visible light camera. Global stereocorrelation (SC) is proposed to register pictures shot by both imaging systems. The stereo rig is calibrated by using a NURBS representation of the 3D target. The projection matrices are determined by an integrated approach. The effect of gray level and distortion corrections is assessed on the projection matrices. SC is performed once the matrices are calibrated to measure 3D displacements. Amplitudes varying from 0 to 800 µm are well captured for in-plane and out-of-plane motions. It is shown that when known rigid body translations are applied to the target, the calibration can be improved when its actual metrology is approximate. Applications are shown for two different setups for which the resolution of the IR camera has been modified