Target tracking in the recommender space: Toward a new recommender system based on Kalman filtering

In this paper, we propose a new approach for recommender systems based on target tracking by Kalman filtering. We assume that users and their seen resources are vectors in the multidimensional space of the categories of the resources. Knowing this space, we propose an algorithm based on a Kalman filter to track users and to predict the best prediction of their future position in the recommendation space

Assessment of International Economic Policy Models and Measures: Lessons for Canada

We consider a typology of four social and economic policy models each pertaining to different groups of countries. These four policy systems namely the Nordic model, the Anglo-Saxon model, the Continental model, and the Mediterranean model, are described individually and in terms of selected public policies. In particular, we review the Swedish economic experience in promoting flexible labour markets and reforming its education sector, the French regulatory reforms in telecommunications and health care sectors, the competitive compulsory tendering and best value reforms in the United Kingdom, and the recent economic growth led by trade in Chile. Finally, we draw important lessons for reforms in Canada. Nous analysons quatre systèmes socio-économiques qui représentent différents groupes de pays. Ces modèles socio-économiques incluant le modèle nordique, l’anglo-saxon, le continental et le méditerranéen sont décrits à travers quelques politiques publiques instaurées dans certains pays. En particulier, nous étudions les réformes de la Suède dans les secteurs de l’éducation et du marché du travail, de la France dans les télécommunications et la santé, du Royaume-Uni dans l’attribution des contrats dans le secteur public, et du Chili pour son expansion économique liée au commerce. Suite à cette analyse, nous identifions des leçons importantes et quelques avenues de réformes pour le Canada.Nordic economic model, Anglo-Saxon economic model, continental economic model, mediterranean economic model, economic reforms, Canada., Modèle socio-économique nordique, modèle socio-économique anglo-saxon, modèle socio-économique continental, modèle socio-économique méditerranéen, réformes économiques, Canada.

Toward a Robust Diversity-Based Model to Detect Changes of Context

Being able to automatically and quickly understand the user context during a session is a main issue for recommender systems. As a first step toward achieving that goal, we propose a model that observes in real time the diversity brought by each item relatively to a short sequence of consultations, corresponding to the recent user history. Our model has a complexity in constant time, and is generic since it can apply to any type of items within an online service (e.g. profiles, products, music tracks) and any application domain (e-commerce, social network, music streaming), as long as we have partial item descriptions. The observation of the diversity level over time allows us to detect implicit changes. In the long term, we plan to characterize the context, i.e. to find common features among a contiguous sub-sequence of items between two changes of context determined by our model. This will allow us to make context-aware and privacy-preserving recommendations, to explain them to users. As this is an ongoing research, the first step consists here in studying the robustness of our model while detecting changes of context. In order to do so, we use a music corpus of 100 users and more than 210,000 consultations (number of songs played in the global history). We validate the relevancy of our detections by finding connections between changes of context and events, such as ends of session. Of course, these events are a subset of the possible changes of context, since there might be several contexts within a session. We altered the quality of our corpus in several manners, so as to test the performances of our model when confronted with sparsity and different types of items. The results show that our model is robust and constitutes a promising approach.Comment: 27th IEEE International Conference on Tools with Artificial Intelligence (ICTAI 2015), Nov 2015, Vietri sul Mare, Ital

Effect of partial wetting on liquid/solid mass transfer in trickle bed reactors

The wetting efficiency of liquid trickle flow over a fixed bed reactor has been measured for a wide range of parameters including operating conditions, bed structure and physico-chemistry of liquid/solid phases. This data bank has been used to develop a new correlation for averaged wetting efficiency based on five different non-dimensional numbers. Finally liquid/solid mass transfer has been determined in partial wetting conditions to analyse what are the respective effects of wetting and liquid/gas flow turbulence. These effects appear to be separated: wetting being acting on liquid/solid interfacial area while the liquid/solid mass transfer coefficient is mainly connected to flow turbulence through the interstitial liquid velocity. A correlation has been proposed for liquid/solid mass transfer coefficient at very low liquid flow rate