Personne :
Rousseau, Alain N.

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Alain N.
Université Laval. Faculté de foresterie, de géographie et de géomatique
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Voici les éléments 1 - 5 sur 5
  • Publication
    Agent-based supply-chain planning in the forest products industry
    (Springer, 2008-02-02) Frayret, Jean-Marc; Gaudreault, Jonathan; Rousseau, Alain N.; Harvey, Steve; D'Amours, Sophie
    The new economic challenges and recent trends in globalization have made it very difficult for Canadian forest product companies to improve their financial position without the coordinated involvement of the entire company, including their supply chains (distributed facilities, company offices, industrial customers, and distributors). Such a new level of efficiency involves their distributed facilities and offices spread around the world, and their customers. One consequence of this new reality is that forest products companies are now facing the need to re-engineer their organizational processes and business practices with their partners. To do this they must adopt new technologies to support the coordination of their planning and control efforts in a customer-centered environment. This paper first proposes a generic software architecture for development of an experimentation environment to design and test distributed advanced planning and scheduling systems. This architecture enables combination of agent-based technology and operations research-based tools in order to first take advantage of the ability of agent technology to integrate distributed decision problems, and, second, to take advantage of the ability of operations research to develop and exploit specific normative decision models. Next, this paper describes how this architecture has been configured into an advanced planning and scheduling tool for the lumber industry. Finally, we present how an application of this advanced planning tool is currently being validated and tested in a real manufacturing setting.
  • Publication
    Accès libre
    Distributed operations planning in the softwood lumber supply chain : models and coordination
    (Centre interuniversitaire de recherche sur les réseaux d'entreprises, la logistique et le transport, 2009-02-01) Frayret, Jean-Marc; Gaudreault, Jonathan; Rousseau, Alain N.; Forget, Pascal; D'Amours, Sophie
    Agent-based technology provides a natural approach to model supply chain networks. Each production unit, represented by an agent, is responsible for planning its operations and uses communication to coordinate with the others. In this paper, we study a softwood lumber supply chain made of three planning units (sawing unit, drying unit and finishing unit). We define the problems and propose agent-specific mathematical models to plan and schedule operations. Then, in order to coordinate these plans between the three agents, we propose different coordination mechanisms. Using these developments, we show how an agent-based simulation tool can be used to integrate planning models and evaluate different coordination mechanisms.
  • Publication
    Accès libre
    Impacts of high precipitation on the energy and water budgets of a humid boreal forest
    (Elsevier, 2019-10-24) Isabelle, Pierre-Erik; Anctil, François; Nadeau, Daniel; Rousseau, Alain N.; Music, Biljana; Jutras, Sylvain
    The boreal forest will be strongly affected by climate change and in turn, these vast ecosystems may significantly impact global climatology and hydrology due to their exchanges of carbon and water with the atmosphere. It is now crucial to understand the intricate relationships between precipitation and evapotranspiration in these environments, particularly in less-studied locations characterized by a cold and humid climate. This study presents state-of-the-art measurements of energy and water budgets components over three years (2016–2018) at the Montmorency Forest, Québec, Canada: a balsam fir boreal forest that receives ∼1600 mm of precipitation annually (continental subarctic climate; Köppen classification subtype Dfc). Precipitation, evapotranspiration and potential evapotranspiration at the site are compared with observations from thirteen experimental sites around the world. These intercomparison sites (89 study-years) encompass various types of climate and vegetation (black spruces, jack pines, etc.) encountered in boreal forests worldwide. The Montmorency Forest stands out by receiving the largest amount of precipitation. Across all sites, water availability seems to be the principal evapotranspiration constraint, as precipitation tends to be more influential than potential evapotranspiration and other factors. This leads to the Montmorency Forest generating the largest amount of evapotranspiration, on average ∼550 mm y−1. This value appears to be an ecosystem maximum for evapotranspiration, which may be explained either by a physiological limit or a limited energy availability due to the presence of cloud cover. The Montmorency Forest water budget evacuates the precipitation excess mostly by watershed discharges, at an average rate of ∼1050 mm y−1, with peaks during the spring freshet. This behaviour, typical of mountainous headwater basins, necessarily influence downstream hydrological regimes to a large extent. This study provides a much needed insight in the hydrological regimes of a humid boreal-forested mountainous watershed, a type of basin rarely studied with precise energy and water budgets before.
  • Publication
    Combined planning and scheduling in a divergent production system with co-production : a case study in the lumber industry
    (Elsevier, 2010-11-20) Frayret, Jean-Marc; Gaudreault, Jonathan; Rousseau, Alain N.; D'Amours, Sophie
    Many research initiatives carried out in production management consider process planning and operations scheduling as two separate and sequential functions. However, in certain contexts, the two functions must be better integrated. This is the case in divergent production systems with co-production (i.e. production of different products at the same time from a single product input) when alternative production processes are available. This paper studies such a context and focuses on the case of drying and finishing operations in a softwood lumber facility. The situation is addressed using a single model that simultaneously performs process planning and scheduling. We evaluate two alternative formulations. The first one is based on mixed integer programming (MIP) and the second on constraint programming (CP). We also propose a search procedure to improve the performance of the CP approach. Both approaches are compared with respect to their capacity to generate good solutions in short computation time.
  • Publication
    Estimating sensible and latent heat fluxes over an inland water body using optical and microwave scintillometers
    (Springer, 2022-09-15) Pierre, Adrien; Isabelle, Pierre-Erik; Nadeau, Daniel; Thiboult, Antoine; Perelet, Alexei; Rousseau, Alain N.; Anctil, François; Deschamps, Jaril
    Les flux de chaleurs turbulents sont encore trop rarement observés au-dessus des plans d’eau continentaux comme les lacs ou les réservoirs, alors que cela demeure essentiel pour le paramétrage des modèles de prévisions météorologiques et de projections climatiques. La scintillométrie permet d’estimer à l’échelle régionale (~km2) les flux turbulents, mais peu d’études ont évalué sa performance au-dessus de plans d’eau. Cette étude compare les flux de chaleurs turbulents issus de la méthode de scintillométrie avec ceux issus d’un système de covariance des tourbillons installé sur un quai flottant, au-dessus d’un réservoir hydroélectrique boréal, dimictique, de 85 km2, situé dans l’est du Canada (50.59°N, 63.24°O). À notre connaissance, il s'agit de l'une des premières études à quantifier l'évaporation sur un plan d'eau intérieur à l'aide d'un ensemble de scintillomètres optiques et micro-ondes. Du 14 août au 9 octobre 2019, les faisceaux des scintillomètres ont sondé l’atmosphère sur une distance de 1.7 km au-dessus du réservoir (10 m) dans une zone ayant jusqu’à 100 m de profondeur. Quarante-neuf jours de données ont été récoltés. Cette étude quantifie l'impact de la stabilité atmosphérique sur les flux calculés et explore l'utilisation des différences de température à l'interface eau-air à proximité du centre du faisceau du scintillomètre pour estimer correctement la direction du flux de chaleur sensible. Les méthodes de scintillométrie corrèlent bien avec les estimations de la covariance des tourbillons pour les flux de chaleur sensible (R2 jusqu'à 0.86, 43% de biais), tandis que la concordance diminue pour les flux de chaleur latente (R2 jusqu'à 0,58, 70% de biais). Le scintillomètre a mesuré des flux de chaleur latente beaucoup plus importants que le système de covariance des tourbillons. Ces résultats peuvent être dus à l'empreinte plus grande des scintillomètres qui captent une plus grande hétérogénéité des flux.