Apports des rôles à la construction et à l'expérimentation de modèles multi-agents pour la gestion de ressources renouvelables

Le formalisme Agent-Groupe-Rôle propose de recourir à des abstractions organisationnelles (groupes et rôles) pour concevoir des systèmes multi-agents (SMA) selon une approche sociale, ou organisation centrée. Plutôt que de se concentrer sur les activités des agents, le concepteur d'un système AGR se concentre sur la structuration de ces activités. Dans le champ de la gestion de ressources renouvelables, les modélisateurs doivent apréhender des systèmes complexes où des dynamiques sociales et physiques se déroulent dans différents niveaux d'organisation entrelacés. Le formalisme AGR permet de représenter explicitement ces niveaux d'organisation et leurs articulations. Cette communication se concentre sur l'apport des rôles à la modélisation multi-agent pour la gestion de ressources renouvelables. Après avoir discuté du concept de rôle en informatique, les différents types de rôles introduits dans le modèle AGR d'une application de gestion d'étiage dans la vallée de la Drôme sont décrits. La question de la composition des rôles et la manière dont elle est résolué dans le cas de la Drôme sera examiné. Sur la base de cet exemple, un bilan des apports et limites de l'utilisation des rôles en termes d'expressivité et de modularité des modèles est dressé en conclusion / The Agent-Group-Role-Formalism has been introduced in the field of computer science as a possible instantiation of an organization-centred approach of multi-agent systems (MAS). Using groups and roles in MAS design, the AGR formalism brings the focus from agents activities description to agents activities structuring. In the field of agent-based modelling (ABM) for renewable resources management, modellers are facing complex systems where social and physical dynamics take place within various interwoven levels of organization. Using AGR formalism is a way to explicitly represent the various levels of organization of a system and their articulations. This paper focuses on the use of roles in ABM for renewable resources management. The concept of role in computer science is first discussed. Then, different types of roles arising from an application case in the southern France Drôme river valley are described. The issue of roles composition and how it is resolved in the Drôme model is examined. The paper concludes on the contributions and on the limits that using roles brings to ABM modularity and expressivit

Perceptual modelling of environmental Indicators to assess land uses impacts on water quality

International audienceStreams’ functioning is closely influenced by land uses along the stream itself and throughout the catchment. Land uses could both translate the natural environment or results of increasing human activities. These different land uses generate various (positive or negative) pressures depending on kind and intensity that alter river water quality for different scales of time and space. The objective of this research, applied on the Saône River (France) is to conceptualize and quantify the interactions between river water quality and land use through spatial modelling. Our methodology is based on (i) the design of indicators’ system using the DPSIR framework (EEA) (ii) the development of relevant environmental indicators able to characterize spatio-temporal evolution of the water quality, land uses and their interactions. The conceptual framework DPSIR helps to understand the global nature and the complexity of the problem; however it constrains the selection and development of environmental indicators. Water quality state is characterized by a bioindicator based on the abundance and the sensitivity of benthic invertebrates that are able to integrate different kinds of pressures at different time scales. The identification of the pressure indicators has been done thanks a literature review. They were built according to the nature of the land use, distance to rivers and location in the watershed. The indicators’ construction has been limited by the representativeness and homogeneity of data gathered from national databases. These data were supplemented by a work of very high spatial resolution land use mapping and by the results of a spatio-temporal change detection analysis

Evaluation de l’influence de l’occupation du sol sur la qualité des cours d’eau en utilisant le cadre DPSIR : application sur le bassin de la Saône

International audienceLes cours d’eau sont des systèmes fragiles et complexes dont le fonctionnement peut être altéré par les activités anthropiques. Guidée par des cadres législatifs stricts et ambitieux, la gestion des cours d’eau implique de nombreux acteurs ayant chacun des objectifs propres en fonction des échelles auxquelles ils opèrent. La littérature identifie clairement l’occupation du sol comme une variable clé de l’estimation des pressions qu’elles soient positives ou négatives. Evaluer les impacts multi échelle de l’occupation du sol sur la qualité des cours d’eau est une question majeure pour les gestionnaires et les scientifiques. L’objectif de notre communication est de présenter l’adaptation du cadre conceptuel DPSIR (" driving forces, pressures, state, impact, responses ") de l’Agence Européenne de l'environnement pour structurer les informations et la construction des indicateurs. Les drivers et les pressions sont estimés à partir des données d'occupation du sol et les données d'états et d'impacts sont estimées par les valeurs d'IBGN et de l'EQR-IBGN, les réponses sont exprimées en termes de potentialités de restauration. Le bassin de la Saône a été choisi comme bassin d’application, en raison de ses caractéristiques hydrogéographiques (superficie de 30 000km² et 9000km de cours d’eau) et de la diversité des activités anthropiques présentes. / Rivers’ functioning can be altered by human activities. Guided by ambitious and rigorous legislative frameworks, rivers management involves many actors, each with specific objectives depending on the scales at which they operate. The literature clearly shows land use as a key variable in the estimation of positive and negative pressures. Assess multi-scale impacts of land use on river water quality is a major issue for water managers and scientist. The aim of our paper is to present the adaptation of DPSIR conceptual framework ("driving forces, pressures, state, impact, responses") promoted by the European Environment Agency to structure the information and the way to build indicators. Drivers and pressures indicators are estimated by land use data. State indicators and impacts indicators are respectively estimated by IBGN and EQR-IBGN values. Responses indicators are characterized by a riverside restoration potentiality. The study case is the Saone catchment because of its hydrogeographical characteristics (area of 30 000km ² and 9000km of rivers) and because of the diversity of human activities in the basin

Pluralité des références spatiales et sociales pour les acteurs d'un contrat de rivière

National audienceRiver contracts lead smoothly stakeholders in a watershed to share points of view and enhance the emergence of collective and coherent projects.With a methodology based on collective decision support experirnents, we have interviewed a set of stakeholders of Orb Valley River Contract.This shows a variability of relevant spaces within our stakeholders sarnple, according to their physical location within or outside the basin, as well as according to their domain of action. These differences are not only based on zoning but also on the relevance of the basin as the cornmon space.As from the social point of view, embedded actors are perceived more through the local conséquences of their actions than through actual interactions. This enhance issues of coherence and conflicts. Orb valley institution seems the main coordination place.Les contrats de rivière amènent d'une manière assez souple les acteurs concernés par la gestion de l'eau sur un bassin versant à partager des points de vue et favorisent l'émergence de projets communs et cohérents. A partir d'expériences en aide à la décision collective, nous avons mené un travail d'enquêtes auprès d'acteurs du Contrat de Rivière de l'Orb. Il en ressort une variabilité des espaces de référence parmi les acteurs interviewés, selon leur localisation physique à l'intérieur ou à l'extérieur du bassin versant, et selon le rayonnement de leur activité (local ou global). Cette variabilité relève non seulement du découpage du même espace d'ensemble, le bassin versant, mais aussi de sa pertinence. Les acteurs, quant à eux, sont plus perçus à travers les conséquences locales de leurs actions que par de réelles interactions, d'où des problèmes de cohérence et de conflits perçus entre ces actions. Le syndicat mixte de la vallée de l'Orb semble le principal lieu de coordination

Assessing the role of riparian vegetation and land use on river ecological status using remote sensing and spatial modelling

International audiencePreserving or restoring the ecological quality of aquatic ecosystems is a major objective of Water Framework Directive. A pending question deals with the gain in river ecological status indicators that could be allowed by restoring riparian tree vegetation. In order to quantify in a statistically relevant way the role of riparian vegetation on river ecosystems, a regional approach is required that mobilizes three complementary fields of research : (1) the use of very high spatial resolution satellite imagery to map river corridor land use and riparian vegetation along large river networks ; (2) the design and quantification of synthetic spatialized indicators of river corridor land use; (3) the development of pressures/state spatialized models that quantify the relation between river corridor land use indicators and river water bodies ecological status indicators. The corresponding methods were developed and implemented on various river basins, particularly over lower Normandy river networks (6000 km long; 157 ecological stations). Results show for instance that in this region, changing the local land use along a river from agriculture to forest (over a buffer 1km long and 30m large on both sides of the river) allows in average to increase by 0.3 points the river ecological status indicators (EQR-IBGN between 0 and 1). Such results are of high interest for decision-makers that can estimate the interest of investing in restoration strategies by anticipating their effect in terms of Water Framework Directive standards

Expériences croisées sur la production d’indicateurs à partir d’une cartographie très haute résolution spatiale de l’occupation du sol dans les corridors rivulaires

International audienceLa mise en oeuvre de la Directive Cadre Européenne sur l’eau (DCE) et les approches centrées sur la biodiversité nécessitent, en particulier, des méthodes d’évaluation et de suivi des sources de pressions. L’occupation du sol dans les corridors rivulaires a un rôle significatif sur la qualité écologique des cours d’eau. Cet espace est donc un facteur de gestion privilégié pour les différents niveaux d’acteurs. Cette communication relate les expériences croisées de développement d’un outil opérationnel de gestion : la production d’indicateurs normatifs et descriptifs d’occupation du sol. Nous présentons les dimensions des besoins de chaque partenaire. Nous montrons ensuite, au travers de la production coordonnée d’indicateurs, les apports réciproques. De la concomitance de besoins est né un véritable travail d’équipe, de co-construction à même d’asseoir la légitimité des indicateurs des différents partenaires. / Water Framework Directive implementation and biodiversity centered approaches require pressure assessment and monitoring methods. Riparian corridors have a significant role on the river ecological quality. So, they are key space of management for stakeholders whatever their working scales. This paper describes the experiences of a cross-development for an operational tool management. The aim is the production of normative and descriptive land use indicators. The objective is to respond to each partner needs. We demonstrate the part brought by reciprocal contributions through coordinated production of indicators. A true project team is born from concomitant needs. This co-construction work permits partners to establish indicators legitimacy

Agent-Based Facilitation of Water Allocation: Case Study in the Drome River Valley

International audienceThe purpose of the 1992 French Water Act is to encourage negotiation and dialogue among local stakeholderswithin a framework which is very similar to a patrimonial approach. Potential use of models in such post-normalapproaches is analyzed. Two kinds of models are compared: one is agent-based, the other follows a more classicalapproach. They are compared according to their contributions as negotiation support tools. This comparisonis based on a specific collective decision process dealing with water allocation at the sub-basin scale, in whichauthors are involved. Both are used to support collective decision processes through simulation of resource usedynamics. Agent-Based Models entail the broadening of spatial information of actors in the process, revealinginter-connected topics not taken into consideration earlier. This makes it possible to remain relevant, despite thesometimes rapidly evolving stakes. The central point of this paper is the implementation, within a practical application,of theories advocating the use of ABM as a collective decision support system. This application promotesa better understanding of the kind of support ABM provides and the way it does so. This is broughtabout more by re-framing the discussion and modifying the representation of the system on the part of thestakeholders than by providing specific agreements

Multidimensional modeling and analysis of large and complex watercourse data: an OLAP-based solution

International audienceThis paper presents the application of Data Warehouse (DW) and On-Line Analytical Processing (OLAP) technologies to the field of water quality assessment. The European Water Framework Directive (DCE, 2000) underlined the necessity of having operational tools to help in the interpretation of the complex and abundant information regarding running waters and their functioning. Several studies have exemplified the interest in DWs for integrating large volumes of data and in OLAP tools for data exploration and analysis. Based on free software tools, we propose an extensible relational OLAP system for the analysis of physicochemical and hydrobiological watercourse data. This system includes: (i) two data cubes; (ii) an Extract, Transform and Load (ETL) tool for data integration; and (iii) tools for OLAP exploration. Many examples of OLAP analysis (thematic, temporal, spatiotemporal, and multiscale) are provided. We have extended an existing framework with complex aggregate functions that are used to define complex analysis indicators. Additional analysis dimensions are also introduced to allow their calculation and also for purposes of rendering information. Finally, we propose two strategies to address the problem of summarizing heterogeneous measurement units by: (i) transforming source data at the ETL tier, and (ii) introducing an additional analysis dimension at the OLAP server tier

Finding Relevant Sequences With The Least Temporal Contradiction Measure: Application to Hydrological Data

International audienceIn this paper, we present a knowledge discovery process applied to hydrological data. To achieve this objective, we apply an algorithm to extract sequential patterns on data collected at stations located along several rivers. The data is pre-processed in order to obtain different spatial proximities and the number of patterns is estimated to highlight the influence of defined spatial relationship. We provide an objective measure of assessment, called the least temporal contradiction, to help the expert in discovering new knowledge. Such elements can be used to assess spatialized indicators to assist the interpretation of ecological and rivers monitoring pressure data