TASK DEFINITION: In this task, you are given a part of an article. Your task is to generate headline (title) for this text. Preferred headlines are under fifteen words.
PROBLEM: Résumé. Le crowdsourcing, un enjeu économique majeur, est le fait d’externaliser une tâche interne d’une entreprise vers le grand-public, la foule. C’est ainsi une forme de sous-traitance digitale destinée à toute personne susceptible de pouvoir réaliser la tâche demandée généralement rapide et non automatisable. L’évaluation de la qualité du travail des participants est cependant un problème majeur en crowdsourcing. En effet, les contributions doivent être contrôlées pour assurer l’efficacité et la pertinence d’une campagne. Plusieurs méthodes ont été proposées pour évaluer le niveau d’expertise des participants. Ce travail a la particularité de proposer une méthode de calcul de degrés d’expertise en présence de données dont l’ordre de classement est connu. Les degrés d’expertise sont ensuite considérés sur des données sans ordre pré-établi. Cette méthode fondée sur la théorie des fonctions de croyance tient compte des incertitudes des réponses et est évaluée sur des données réelles d’une campagne réalisée en 2016.

SOLUTION: Une mesure d’expertise pour le crowdsourcing

PROBLEM: Intrusion detection systems (IDSs) fall into two high-level categories: network-based systems (NIDS) that monitor network behaviors, and host-based systems (HIDS) that monitor system calls. In this work, we present a general technique for both systems. We use anomaly detection, which identifies patterns not conforming to a historic norm. In both types of systems, the rates of change vary dramatically over time (due to burstiness) and over components (due to service difference). To efficiently model such systems, we use continuous time Bayesian networks (CTBNs) and avoid specifying a fixed update interval common to discrete-time models. We build generative models from the normal training data, and abnormal behaviors are flagged based on their likelihood under this norm. For NIDS, we construct a hierarchical CTBN model for the network packet traces and use Rao-Blackwellized particle filtering to learn the parameters. We illustrate the power of our method through experiments on detecting real worms and identifying hosts on two publicly available network traces, the MAWI dataset and the LBNL dataset. For HIDS, we develop a novel learning method to deal with the finite resolution of system log file time stamps, without losing the benefits of our continuous time model. We demonstrate the method by detecting intrusions in the DARPA 1998 BSM dataset.

SOLUTION: Intrusion Detection using Continuous Time Bayesian Networks

PROBLEM: Selecting the right web links for a website is important because appropriate links not only can provide high attractiveness but can also increase the website’s revenue. In this work, we first show that web links have an intrinsic multilevel feedback structure. For example, consider a 2-level feedback web link: the 1st level feedback provides the Click-Through Rate (CTR) and the 2nd level feedback provides the potential revenue, which collectively produce the compound 2-level revenue. We consider the context-free links selection problem of selecting links for a homepage so as to maximize the total compound 2-level revenue while keeping the total 1st level feedback above a preset threshold. We further generalize the problem to links with n (n≥2)-level feedback structure. To our best knowledge, we are the first to model the links selection problem as a constrained multi-armed bandit problem and design an effective links selection algorithm by learning the links’ multi-level structure with provable sub-linear regret and violation bounds. We uncover the multi-level feedback structures of web links in two real-world datasets. We also conduct extensive experiments on the datasets to compare our proposed LExp algorithm with two state-of-the-art context-free bandit algorithms and show that LExp algorithm is the most effective in links selection while satisfying the constraint.

SOLUTION:
Multi-level Feedback Web Links Selection Problem: Learning and Optimization