A Branch-and-Bound Algorithm for Array Distributions

An important problem facing parallelizing compilers for distributed memory mimd machines is that of distributing data across processors. This distribution affects the amout of data movements among processors that is required to execute the computations of the input program. This work proposes a branch--and--bound based method to automatically compute a distribution for the arrays of the input program. The method is able to arrange redistributions of data during program execution. To test the proposed method, we have embedded it into an experimental parallelizing compiler for an Intel iPSC=860. Results with this compiler for example like the Livermore Loop Kernels show that the computed data distributions are very good. 1 Introduction Distributed memory mimd computers (DMMs) offer a cost effective performance because they are less expensive to build than shared memory machines and are scalable to a large number of processors. Unfortunately, these machines are not easy to porgram becaus..

Development of a cartographic model for the forest site types delineation in the Belgian Ardenne.

L’article présente une méthode originale permettant l’identification automatisée des types de station ou unités géomorphopédologiques. Elle intègre une clé typologique dans un système d’information géographique (SIG), de manière à produire une couche cartographique décrivant les différents types de station. Les données de base utilisées pour produire cette carte thématique sont la Carte des sols de la Belgique, digitalisée au 1/20.000e, et un modèle numérique de terrain (MNT) construit en utilisant les courbes de niveau digitalisées au départ de la carte topographique au 1/10.000e. La clé typologique s’inspire de la démarche développée dans le catalogue des stations d’Ardenne centrale publié en 1988 par Thill et al., dans la carte de végétation potentielle de Sougnez et Dethioux (1975) et dans la carte des territoires écologiques de Delvaux et Galoux (1962). Les types de station définis sont, par construction, étroitement liés aux familles de sols de la carte des sols et aux syntaxons de la classification phytosociologique. Ils sont ensuite mis en relation avec le Guide du boisement et plusieurs études phytosociologiques et autécologiques réalisées en Région wallonne pour différentes essences forestières. Il est de ce fait possible de cartographier également des niveaux d’aptitude pour ces essences ou encore les habitats potentiels correspondant aux types de station. La clé typologique est valable pour l’Ardenne belge. Elle doit faire l’objet d’une validation sur le terrain, tenant compte des niveaux d’imprécision liés à la nature des données sur lesquelles elle s’appuie. L’intégration de cet outil dans un SIG ouvre des perspectives novatrices dans une démarche d’aménagement forestier intégré et peut jouer un rôle déterminant dans la phase de prospection et d’analyse des sites désignés pour le projet NATURA 2000 initié par l’Union Européenne.The paper presents an original method dealing with the forest site types delineation. The suggested method consists in integrating a typological key in a GIS aiming at producing a thematic map that describes forest site types. Data used are the soil map of Belgium (digitized at the scale 1:20,000) and a digital elevation model built from a topographic map (scale 1:10,000). The typological key is mainly based on the methodology used by Thill et al. (1988) in the site types system for central Ardenne, the potential vegetation map of Sougnez and Dethioux (1975) and the ecoregion map of Delvaux and Galoux (1962). In that respect, site types are closely linked to the soil map and the phytosociological classification. So, they can be connected to the afforestation guide and different phytosociological and autecological studies concerning forest species. It is then possible to map the potential habitats or the site potentialities related to tree species. The key is valid for the Ardenne ecoregion located in Southern Belgium (elevation higher than 300 m). It has to be validated through an intensive use in the field, taking into account its imprecision linked to the types of collected data, chieffly those being digitized. The integration of such a tool in a SIG can be considered as an original way in terms of integrated forest management or forest sites description in the context of the project “Natura 2000” launched by the European Union. The study has been carried out within the framework of an experimental integrated management project concerning the Saint-Hubert forest (17,000 ha)

Spécifications du module d'aide à la codification des actes (sous-projet 3 - CIREA)

livrable du projet RNTS RHE

Mise au point d' un modele cartographique pour la description des stations forestieres en Ardenne belge

Development of a cartographic mdel for the forest site types delineation in the Belgian Ardenne. The paper presents an original method dealing with the forest site types delineation. The suggested method consists in integrating a typological key in a GIS aiming at producing a thematic map that describes forest site types. Data used are the soil map of Belgium (digitized at the scale 1:20,000) and a digital elevation model built from a topographic map (scale 1:10,000). The typological key is mainly based on the methodology used by Thill et al. (1988) in the site types system for central Ardenne, the potential vegetation map of Sougnez and Dethioux (1975) and the ecoregion map of Delvaux and Galoux (1962). In that respect, site types are closely linked to the soil map and the phytosociological classification. So, they can be connected to the afforestation guide and different phytosociological and autecological studies concerning forest species. It is then possible to map the potential habitats or the site potentialities related to tree species. The key is valid for the Ardenne ecoregion located in Southern Belgium (elevation higher than 300 m). It has to be validated through an intensive use in the field, taking into account its imprecision linked to the types of collected data, chieffly those being digitized. The integration of such a tool in a SIG can be considered as an original way in terms of integrated forest management or forest sites description in the context of the project ""Natura 2000"" launched by the European Union. The study has been carried out within the framework of an experimental integrated management project concerning the Saint-Hubert forest (17,000 ha)