Isomorphism of graph classes related to the circular-ones property

We give a linear-time algorithm that checks for isomorphism between two 0-1 matrices that obey the circular-ones property. This algorithm leads to linear-time isomorphism algorithms for related graph classes, including Helly circular-arc graphs, \Gamma-circular-arc graphs, proper circular-arc graphs and convex-round graphs.Comment: 25 pages, 9 figure

Assessing ESA Climate Change Initiative data for the monitoring of phytoplankton abundance and phenology in deep lakes: investigation on Lake Geneva

Lake water quality assessment requires quantification of phytoplankton abundance. Optical satellite imagery allows us to map this information within the entire lake area. The ESA Climate Change Initiative (ESA-CCI) estimates Chl-a concentrations, based on medium resolution satellite data, on a global scale. Chl-a concentrations provided by the ESA-CCI consortium were analyzed to assess their representativeness for water quality monitoring and subsequent phenology studies in Lake Geneva. Based on vertically resolved in-situ data, those datasets were evaluated through match-up comparisons. Because the underlying algorithms do not take into account the vertical distribution of phytoplankton, a specific analysis was performed to evaluate any potential biases in remote sensing estimation, and consequences for observed phenological trends. Different approaches to data averaging were performed to reconstruct Chl-a estimates provided by the remote sensing algorithms. Strong correlation (R-value > 0.89) and acceptable discrepancies (rmse ∼ 1.4 mg.m−3) were observed for the ESA-CCI data. This approach permitted recalibration of the ESA CCI data for Lake Geneva. Finally, merging satellite and in-situ data provided a consistent time series for long term analysis of phytoplankton phenology and its interannual variability since 2002. This combination of in-situ and satellite data improved the temporal resolution of the time series, enabling a more accurate identification of the timing of specific spring events characterising phytoplankton phenology

Fully dynamic recognition of proper circular-arc graphs

We present a fully dynamic algorithm for the recognition of proper circular-arc (PCA) graphs. The allowed operations on the graph involve the insertion and removal of vertices (together with its incident edges) or edges. Edge operations cost O(log n) time, where n is the number of vertices of the graph, while vertex operations cost O(log n + d) time, where d is the degree of the modified vertex. We also show incremental and decremental algorithms that work in O(1) time per inserted or removed edge. As part of our algorithm, fully dynamic connectivity and co-connectivity algorithms that work in O(log n) time per operation are obtained. Also, an O(\Delta) time algorithm for determining if a PCA representation corresponds to a co-bipartite graph is provided, where \Delta\ is the maximum among the degrees of the vertices. When the graph is co-bipartite, a co-bipartition of each of its co-components is obtained within the same amount of time.Comment: 60 pages, 15 figure

Statère gaulois trouvé au pays des Calètes (Seine-Maritime)

Soulignac R. Statère gaulois trouvé au pays des Calètes (Seine-Maritime). In: Gallia, tome 20, fascicule 2, 1962. pp. 409-410

Rapport d'Expertise des Systèmes d'Information MicMac design BD, OSMOSE et SYSTERRE

L'objectif de l'expertise est d'éviter toute redondance entre outils existants tout en s'assurant que les besoins décrits dans le cahier des charges du projet BASE Ecophyto sont couverts

AgroPEPS, un outil web collaboratif de gestion des connaissances pour Produire, Echanger, Pratiquer, S'informer sur les systèmes de culture durables

International audienceAgroPEPS is a collaborative web tool of knowledge management focused on agro-ecology, designed for and with future and potential users of the Joint technology network for ‘innovative cropping system'.Its aims are to capitalize knowledge and experiences in order to allow several actors in agriculture to design, pilot, manage and train innovative cropping systems, which are performant economically, environmentally and socially. Nowadays, developed as a prototype, Agro-PEPS makes available 150 techniques, described and structured according to 5 issues of sustainable development (water, air, soil, fossil resources, biodiversity). To reach them, Agro-PEPS has functionalities of syntactic research by keywords and of semantic research allowing a better targeting. This tool concept finds a favorable echo in the French R&D and training system: we recorded in January 2015 about 240 000 connections on the web site since its start which was confidential due to its prototype status. However its evolution in an operational web tool remains to be formalized.AgroPEPS est un outil web collaboratif de gestion des connaissances dédié à l'agroécologie, conçu pour et avec les futurs utilisateurs dans le cadre du RMT Systèmes de culture innovants. Il a pour objectifs de capitaliser les connaissances et expériences disponibles afin de permettre à différents acteurs du monde agricole de concevoir, piloter, gérer et faire l'apprentissage de systèmes de culture innovants et performants d'un point de vue économique, environnemental et social. Aujourd'hui développé sous forme de prototype il met a disposition des utilisateurs 150 techniques, décrites et structurées en fonction de cinq enjeux de développement durable (l'eau, l'air, le sol, les ressources fossiles et la biodiversité). Pour y accéder, AgroPEPS dispose de fonctionnalités de recherche syntaxique classique par moteur de recherche et de fonctionnalités de recherche sémantique permettant un meilleur ciblage. Ce concept d'outil trouve un écho très favorable dans le monde du développement, de la recherche et de la formation : on dénombre fin janvier 2015 près de 240.000 connexions au site depuis sa mise en ligne pourtant restée "confidentielle" compte-tenu du caractère de prototype de l'outil. Mais son évolution sous la forme d'un outil abouti reste encore à formalise

Isomorphism of graph classes related to the circular-ones property

Discrete Algorithm

An integrated approach for assessing the impact of urban stormwater discharge on the fecal contamination in a recreational lake near Paris

International audienceUrban stormwater discharges contribute to the fecal contamination of recreational lakes. It is essential to assess the spatial and temporal distribution of fecal bacterial indicators in the receiving waterbodies, to prevent public health risks. This study develops for the first time in continental waters an integrated monitoring and modelling approach, linking the SWMM and Delft-3D models and including a detailed monitoring of the stormwater discharge and at different points of the lake, for assessing Escherichia coli (E.coli) dynamics in stormwater discharges and the receiving urban lake. This integrated approach is applied to a recreational shallow lake and its adjacent urban catchment, with a single stormwater outlet which discharges into the lake. The SWMM model parameters are calibrated and validated with continuous measurements of the flow rate and mean concentration of E. coli in the stormwater discharge measured during each rainfall event. Using the simulated flow rate and E. coli concentration at the sewer outlet, the Delft3D-FLOW-WAQ model simulates E. coli transport in the urban lake with previously calibrated hydrodynamic parameters and default values of E. coli parameters. Comparing simulations with E. coli concentrations measured at different points in the lake, this integrated modelling approach yields promising results. Further studies will focus on the development of automatic model coupling and parameter optimisation, as well as on the evaluation of long-term impacts and management scenarios

Utilisation de la modélisation 3D et de la télédétection pour une meilleure compréhension des hétérogénéités spatio-temporelles de l'abondance du phytoplancton dans les grands lacs

International audienceLake biological parameters show important spatio-temporal heterogeneities. This is why explaining the spatial patchiness of phytoplankton abundance has been a recurrent ecological issue and is an essential prerequisite for objectively assessing, protecting and restoring freshwater ecosystems. The drivers of these heterogeneities can be identified by modelling their dynamics. This approach is useful for theoretical and applied limnology. In this study, a 3D hydrodynamic model of LakeGeneva (France/Switzerland) was created. It is based on the Delft3D suite software and includes the main tributary (Rhône River) and two-dimensional high-resolution meteorological forcing. It provides 3D maps of water temperature and current velocities with a 1 h time step on a 1 km horizontal grid size and with a vertical resolution of 1 m near the surface to 7 m at the bottom of the lake. The dynamics and the drivers of phytoplankton heterogeneities were assessed by combining the outputs of the model and chlorophyll-a concentration (Chl-a) data from MERIS satellite images between 2008 and 2012. Results highlight physical mechanisms responsible for the occurrence of seasonal hot-spots in phytoplankton abundance in the lake. At the beginning of spring, Chl-a heterogeneities are usually caused by an earlier onset of phytoplankton growth in the shallowest and more sheltered areas; spatial differences in the timing of phytoplankton growth can be explained by spatial variability in thermal stratification dynamics. In summer, transient and locally higher phytoplankton abundances are observed in relation to the impact of basin-scale upwelling

Utilisation de la modélisation 3D et de la télédétection pour une meilleure compréhension des hétérogénéités spatio-temporelles de l'abondance du phytoplancton dans les grands lacs

International audienceLake biological parameters show important spatio-temporal heterogeneities. This is why explaining the spatial patchiness of phytoplankton abundance has been a recurrent ecological issue and is an essential prerequisite for objectively assessing, protecting and restoring freshwater ecosystems. The drivers of these heterogeneities can be identified by modelling their dynamics. This approach is useful for theoretical and applied limnology. In this study, a 3D hydrodynamic model of LakeGeneva (France/Switzerland) was created. It is based on the Delft3D suite software and includes the main tributary (Rhône River) and two-dimensional high-resolution meteorological forcing. It provides 3D maps of water temperature and current velocities with a 1 h time step on a 1 km horizontal grid size and with a vertical resolution of 1 m near the surface to 7 m at the bottom of the lake. The dynamics and the drivers of phytoplankton heterogeneities were assessed by combining the outputs of the model and chlorophyll-a concentration (Chl-a) data from MERIS satellite images between 2008 and 2012. Results highlight physical mechanisms responsible for the occurrence of seasonal hot-spots in phytoplankton abundance in the lake. At the beginning of spring, Chl-a heterogeneities are usually caused by an earlier onset of phytoplankton growth in the shallowest and more sheltered areas; spatial differences in the timing of phytoplankton growth can be explained by spatial variability in thermal stratification dynamics. In summer, transient and locally higher phytoplankton abundances are observed in relation to the impact of basin-scale upwelling