Compilation de CSPs : carte de complexité des MDDs non-déterministes

National audienceLes CSPs fournissent un cadre puissant pour la représentation de problèmes très divers. La difficulté est que la plupart des requêtes associées aux CSPs sont NP-difficiles, mais doivent dans certains contextes être traitées « en ligne ». C’est pour cette raison que les diagrammes de décision multivalués (MDDs) ont été proposés pour la compilation de CSPs. Cet article dresse une carte de compilation des MDDs, dans l’esprit de la carte de la famille des NNFs de Darwiche et Marquis, en analysant les MDDs selon leur compacité et les requêtes et transformations qu’ils supportent en temps polynomial. Les MDDs déterministes et ordonnés généralisant les diagrammes de décision binaire ordonnes à des variables non-booléennes, le fait que leurs propriétés soient similaires n’est pas surprenant. Cependant, notre étude met en avant l’intérêt des MDDs ordonnes non déterministes : restreint aux variables booléennes, ce fragment est strictement plus compact que ceux des OBDDs et des DNFs, et admet des performances proches de celles des DNNFs. La comparaison aux MDDs classiques montre que relâcher la contrainte du déterminisme améliore la compacité et permet a plus de transformations d’être supportées en temps polynomial. Des expériences sur des problèmes aléatoires confirment le gain en compacité

Substratum géologique et partage des terres dans le sud du Tchad Région des lacs de Léré et de Tréné et réserve de faune de Binder Nayri

National audienceÀ travers une analyse du substratum géologique et de l'occupation du sol dans unerégion sahélo-soudanienne au sud du Tchad : le massif du Mayo-Kébbi (carte 1), nousproposons de montrer :– quels sont les liens entre la nature du substratum géologique (socle et formationssuperficielles) et les paysages ;– comment se répartissent les ressources naturelles entre les paysages et comment seréalise le partage entre les zones fortement anthropisées et les zones naturelles dédiéesà une réserve de faune.Basée sur une analyse de terrain spatialisée (cartographie géologique et pédologique,enquête villageoise...), complétée par des éléments de bibliographie, la méthode faitégalement appel aux outils de télédétection pour la mise à jour de la carte d'occupationdu sol. La compilation globale aboutit à une meilleure compréhension de l’organisationdes paysages

Astrometry with "Carte du Ciel" plates, San Fernando zone. II. CdC-SF: a precise proper motion catalogue

The historic plates of the "Carte du Ciel", an international cooperative project launched in 1887, offer valuable first-epoch material for the determination of absolute proper motions. We present the CdC-SF, an astrometric catalogue of positions and proper motions derived from the "Carte du Ciel" plates of the San Fernando zone, photographic material with a mean epoch of 1901.4 and a limiting magnitude of V~16, covering the declination range of -10deg < declination < -2deg. Digitization has been made using a conventional flatbed scanner. Special techniques have been developed to handle the combination of plate material and the large distortion introduced by the scanner. The equatorial coordinates are on the ICRS defined by Tycho-2, and proper motions are derived using UCAC2 as second-epoch positions. The result is a catalogue with positions and proper motions for 560000 stars, covering 1080 degrees squared. The mean positional uncertainty is 0.20" (0.12" for well-measured stars) and the proper-motion uncertainty is 2.0 mas/yr (1.2 mas/yr for well-measured stars). The proper motion catalogue CdC-SF is effectively a deeper extension of Hipparcos, in terms of proper motions, to a magnitude of 15.Comment: 10 pages, 13 figures, 6 tables. Accepted for publication in A&

Breaking the silence of the 500-year-old smiling garden of everlasting flowers: The En Tibi book herbarium

We reveal the enigmatic origin of one of the earliest surviving botanical collections. The 16th-century Italian En Tibi herbarium is a large, luxurious book with c. 500 dried plants, made in the Renaissance scholarly circles that developed botany as a distinct discipline. Its Latin inscription, translated as “Here for you a smiling garden of everlasting flowers”, suggests that this herbarium was a gift for a patron of the emerging botanical science. We follow an integrative approach that includes a botanical similarity estimation of the En Tibi with contemporary herbaria (Aldrovandi, Cesalpino, “Cibo”, Merini, Estense) and analysis of the book’s watermark, paper, binding, handwriting, Latin inscription and the morphology and DNA of hairs mounted under specimens. Rejecting the previous origin hypothesis (Ferrara, 1542–1544), we show that the En Tibi was made in Bologna around 1558. We attribute the En Tibi herbarium to Francesco Petrollini, a neglected 16th-century botanist, to whom also belongs, as clarified herein, the controversial “Erbario Cibo” kept in Rome. The En Tibi was probably a work on commission for Petrollini, who provided the plant material for the book. Other people were apparently involved in the compilation and offering of this precious gift to a yet unknown person, possibly the Habsburg Emperor Ferdinand I. The En Tibi herbarium is a Renaissance masterpiece of art and science, representing the quest for truth in herbal medicine and botany. Our multidisciplinary approach can serve as a guideline for deciphering other anonymous herbaria, kept safely “hidden” in treasure rooms of universities, libraries and museums

Breaking the silence of the 500-year-old smiling garden of everlasting flowers: The En Tibi book herbarium

We reveal the enigmatic origin of one of the earliest surviving botanical collections. The 16th-century Italian En Tibi herbarium is a large, luxurious book with c. 500 dried plants, made in the Renaissance scholarly circles that developed botany as a distinct discipline. Its Latin inscription, translated as “Here for you a smiling garden of everlasting flowers”, suggests that this herbarium was a gift for a patron of the emerging botanical science. We follow an integrative approach that includes a botanical similarity estimation of the En Tibi with contemporary herbaria (Aldrovandi, Cesalpino, “Cibo”, Merini, Estense) and analysis of the book’s watermark, paper, binding, handwriting, Latin inscription and the morphology and DNA of hairs mounted under specimens. Rejecting the previous origin hypothesis (Ferrara, 1542–1544), we show that the En Tibi was made in Bologna around 1558. We attribute the En Tibi herbarium to Francesco Petrollini, a neglected 16th-century botanist, to whom also belongs, as clarified herein, the controversial “Erbario Cibo” kept in Rome. The En Tibi was probably a work on commission for Petrollini, who provided the plant material for the book. Other people were apparently involved in the compilation and offering of this precious gift to a yet unknown person, possibly the Habsburg Emperor Ferdinand I. The En Tibi herbarium is a Renaissance masterpiece of art and science, representing the quest for truth in herbal medicine and botany. Our multidisciplinary approach can serve as a guideline for deciphering other anonymous herbaria, kept safely “hidden” in treasure rooms of universities, libraries and museums

Cartographie des anciens cours d’eau, lignes de creux et des bassins versants de l'île de Montréal

Guide et ses annexes à destination des utilisateurs des cartes relatives à la recherche "Cartographie des anciens cours d’eau, lignes de creux et des bassins versants de l'île de Montréal". Aide à la compréhension du contexte, des définitions, de la méthodologie et des hypothèses relatives à la réalisation des documents cartographiques suivants: ■ Carte des anciens cours d'eau de l'île de Montréal, Mahaut V., 2016 ■ Carte des creux et crêtes et des voiries de l'île de Montréal, 1:20.000, Mahaut V., 2016 [http://hdl.handle.net/1866/16313] ■ Carte des creux et crêtes et de l'altimétrie de l'île de Montréal, 1:20.000, Mahaut V.,2016 [http://hdl.handle.net/1866/16312] ■ Recensement cartographique des anciens cours d’eau de l’île de Montréal et tracé des creux et des crêtes, Carte index 1:50.000, Cartes A4, B3, B4, C3, C4, D1, D2, D3, D4, E1, E2, E3, E4, 1:10.000, Mahaut V., 2016 [http://hdl.handle.net/1866/16311]Guide and appendices for users of "Cartography of the island of Montreal's former watercourses, thalwegs, and watersheds." Aid for understanding the context, definitions, methodology, and hypotheses relating to the production of the following cartographic documents: ■ Map of the island of Montreal's former watercourses, Mahaut V., 2016 ■ Map of the island of Montreal's thalwegs, crest lines, and road network, 1:20.000, Mahaut V., 2016 [http://hdl.handle.net/1866/16313] ■ Map of the island of Montreal's thalwegs, crest lines, and altimetry, 1:20.000, Mahaut V., 2016 [http://hdl.handle.net/1866/16312] ■ Cartographic survey of the island of Montreal's former watercourses with thalwegs and crest lines, Index map 1:50.000, Maps A4, B3, B4, C3, C4, D1, D2, D3, D4, E1, E2, E3, E4, 1:10.000, Mahaut V., 2016 [http://hdl.handle.net/1866/16311]La cartographie des anciens cours d’eau de Montréal fait défaut et devait être refaite de manière la plus documentée et la plus transparente possible. En effet, deux cartes sont jusqu’à présent utilisées comme outil de référence : la «Carte topographique de l'île de Montréal de 1542 à 1642», dressée vers 1930 par l’architecte Aristide Beaugrand-Champagne dont on ne connaît pas les sources ayant permis de l’établir et qui présente de nombreuses incohérences hydrographiques ; et la carte « Montréal - Ruisseaux et fossés », dressée par les Travaux Publics - Eaux et Assainissement en 1958, qui couvre partiellement l’île et dont une partie des sources référencées sur la carte a disparu des archives de la Ville. Un nouveau travail de recensement des cours d’eau de l’île au complet a été entrepris par l’équipe de Valérie Mahaut, professeure à l’École d’architecture de la Faculté de l’aménagement de l’Université de Montréal. Après consultation de plus d’une centaine de cartes historiques originales, une trentaine ont été sélectionnées, géoréférencées, retracées et constituent le cœur de la compilation de ce travail. De ces données, plusieurs cartes ont été produites et seront mises en ligne en accès libre pour servir de référence à différentes disciplines et utilisateurs. Cette compilation s’inscrit dans une recherche plus vaste et prospective visant une gestion intégrée des eaux de ruissellement en milieu urbain. Un travail d’interprétation a été fait sur base de ces données de sorte que les cartes produites fournissent également les creux (talwegs) et les crêtes (limites de bassin versant ou limites de partage des eaux) des anciens cours d’eau en vue de la mise en place de « Nouvelles Rivières Urbaines » à Montréal.The cartography of the island of Montreal's former watercourses is lacking and must be redone in the most documented and transparent way possible. Two maps are currently used as references: "Carte topographique de l'île de Montréal de 1542 à 1642" [Topographic map of the island of Montreal from 1542 to 1642], drawn around 1930 by architect and researcher Aristide Beaugrand-Champagne, for which sources were not provided, and which contains numerous hydrographic incoherencies; and "Montréal - Ruisseaux et fossés" [Montreal - Streams and ditches], drawn by the Eaux et Assainissement [Water and Sanitation] division of Montreal’s Public Works Department in 1958, which covers part of the island, and for which some of the sources referenced have disappeared from the city’s archives. A new survey of the island's watercourses has been undertaken by the team of Valérie Mahaut, assistant professor at the school of architecture of the Faculté de l’aménagement, Université de Montréal. After consulting more than one hundred original historical maps, some thirty were selected, geolocalized, and plotted; they form the core of the compilation work conducted in this study. From this data, several new maps were produced and made available online for free to serve as references for various disciplines and users. This surveying work is merely the first step in a broader project which promotes integrated rainwater management in urban areas. The data collected was interpreted so that the maps produced also show the thalwegs and crest lines (ridge lines or watershed boundary lines) of the island of Montreal's former watercourses with the goal of establishing "New Urban Rivers".Institut de Recherche en Histoire de l’Architecture (IRHA) Fonds de recherche du Québec - Société et culture (FQRSC) Mobilisation des connaissances de l’Université de Montréal - Conseil de recherche en sciences humaines (UdeM-CRSH

Astrometry with "Carte du Ciel" plates, San Fernando zone. I. Digitization and measurement using a flatbed scanner

We present an original method of digitizing and astrometrically reducing "Carte du Ciel" plate material using an inexpensive flatbed scanner, to demonstrate that for this material there is an alternative to more specialized measuring machines that are very few in number and thus not readily available. The sample of plates chosen to develop this method are original "Carte du Ciel" plates of the San Fernando zone, photographic material with a mean epoch 1903.6, and a limiting photographic magnitude ~14.5, covering the declination range of -10 < dec < -2. Digitization has been made using a commercial flatbed scanner, demonstrating the internal precision that can be attained with such a device. A variety of post-scan corrections are shown to be necessary. In particular, the large distortion introduced by the non-uniform action of the scanner is modelled using multiple scans of each plate. We also tackle the specific problems associated with the triple-exposure images on some plates and the grid lines present on all. The final measures are reduced to celestial coordinates using the Tycho-2 Catalogue. The internal precision obtained over a single plate, 3microns ~ 0.18" in each axis, is comparable to what is realized with similar plate material using slower, less affordable, and less widely available conventional measuring machines, such as a PDS microdensitometer. The accuracy attained over large multi-plate areas, employing an overlapping plate technique, is estimated at 0.2".Comment: 16 pages, 19 figures and 3 tables. Accepted for publication in A&

Evolution of a Paleoproterozoic “weak type” orogeny in the West African Craton (Ivory Coast).

International audienceThe Paleoproterozoic domain of Ivory Coast lies in the central part of the West African Craton (WAC) and is mainly constituted by TTG, greenstones, supracrustal rocks and leucogranites. A compilation of metamorphic and radiometric data highlights that: i) metamorphic conditions are rather homogeneous through the domain, without important metamorphic jumps, ii) HP-LT assemblages are absent and iii) important volumes of magmas emplaced during the overall Paleoproterozoic orogeny suggesting the occurrence of long-lived rather hot geotherms. Results of the structural analysis, focused on three areas within the Ivory Coast, suggest that the deformation is homogeneous and distributed through the Paleoproterozoic domain. In details, results of this study point out the long-lived character of vertical movements during the Eburnean orogeny with a two folds evolution. The first stage is characterized by the development of “domes and basins” geometries without any boundary tectonic forces and the second stage is marked by coeval diapiric movements and horizontal regional-scale shortening. These features suggest that the crust is affected by vertical movements during the overall orogeny. The Eburnean orogen can then be considered as an example of longlived Paleoproterozoic “weak type” orogen