Collective and emergent problem solving based on multi-agent systems : principles and applications

A multi-agent system is composed of numerous entities, called agents, interacting in various ways between them and their common environment. This technology is applied in many domains like computer vision, robotics, system simulation or electronic commerce. We consider that problems occuring in signal processing could also be tackled by this technology. We present first the basic tools available for multi-agent systems designers : models, platforms and methodologies. Two projects illustrate our purpose : SCALA in the management of aerospace fighter patrol, and goods routing. We focus then on the adaptation ability of these systems considered as an emergent problem solving question. We detailed in this field the AMAS (Adaptive Multi-Agent System) theory allowing a MAS design where the global fonction is derived from the cooperative self-organisation of its components. An example on flood forecast gives implementation information of this theory.Un système multi-agent est constitué d’un grand nombre d’entités, appelées agents, en interaction entre elles au sein d’un même environnement. Cette technologie aborde de nombreux domaines d’applications comme la vision par ordinateur, la robotique, la simulation de systèmes, le commerce électronique. Nous considérons que les questions abordées en traitement du signal sont très pertinentes dans un cadre multi-agent. Nous présentons d’abord les principaux outils dont disposent les concepteurs de systèmes multi-agents à savoir : des modèles, des plates-formes et des méthodes de développement. Puis, le projet SCALA de simulation de résolution de problèmes par des patrouilles aériennes et un projet de simulation de système de transports illustrent la résolution de problèmes à l’aide de systèmes multi-agents. Ensuite, nous nous intéressons plus particulièrement aux capacités d’adaptation de tels systèmes que nous abordons comme une question de résolution émergente de problèmes. Dans ce cadre nous décrivons en détail la théorie AMAS (Adaptive Multi-Agent System) qui permet de concevoir des systèmes dont la fonction globale émerge à partir d’un processus d’auto-organisation coopérative de ses parties. Une application en prévision de crues donne une indication plus précise des capacités de telles approches

Adhesive free-standing multilayer films containing sulfated levan for biomedical applications

This work is the first reporting the use of layer-by-layer to produce adhesive free-standing (FS) films fully produced using natural-based macromolecules: chitosan (CHI), alginate (ALG) and sulfated levan (L-S). The deposition conditions of the natural polymers were studied through zeta potential measurements and quartz crystal microbalance with dissipation monitoring analysis. The properties of the FS films were evaluated and compared with the control ones composed of only CHI and ALG in order to assess the influence of levan polysaccharide introduced in the multilayers. Tensile tests, dynamic mechanical analysis and single lap shear strength tests were performed to evaluate the mechanical properties of the prepared FS films. The presence of L-S conferred both higher tensile strength and shear strength to the developed FS membranes. The results showed an adhesion strength 4 times higher than the control (CHI/ALG) FS films demonstrating the adhesive character of the FS films containing L-S. Morphological and topography studies were carried out revealing that the crosslinking reaction granted the L-S based FS film with a higher roughness and surface homogeneity. Preliminary biological assays were performed by cultivating myoblasts cells on the surface of the produced FS films. Both crosslinked and uncrosslinked FS films containing L-S were cytocompatible and myoconductive.publishe

Spatial and linear correlations between soil and corn

The Technologies setting at Agricultural production system have the main characteristics the vertical productivity, reduced costs, soil physical, chemical and biological improvement to promote production sustainable growth. Thus, the study aimed to determine the variability and the linear and special correlations between the plant and soil attributes in order to select and indicate good representation of soil physical quality for forage productivity. In the growing season of 2006, on the Fazenda Bonança in Pereira Barreto (SP), the productivity of autumn corn forage (FDM) in an irrigated no-tillage system and the soil physical properties were analyzed. The purpose was to study the variability and the linear and spatial correlations between the plant and soil properties, to select an indicator of soil physical quality related to corn forage yield. A geostatistical grid was installed to collect soil and plant data, with 125 sampling points in an area of 2,500 m². The results show that the studied properties did not vary randomly and that data variability was low to very high, with well-defined spatial patterns, ranging from 7.8 to 38.0 m. On the other hand, the linear correlation between the plant and the soil properties was low and highly significant. The pairs forage dry matter versus microporosity and stem diameter versus bulk density were best correlated in the 0-0.10 m layer, while the other pairs - forage dry matter versus macro - and total porosity - were inversely correlated in the same layer. However, from the spatial point of view, there was a high inverse correlation between forage dry matter with microporosity, so that microporosity in the 0-0.10 m layer can be considered a good indicator of soil physical quality, with a view to corn forage yield

Quality indicators in breast cancer care

To define a set of quality indicators that should be routinely measured and evaluated to confirm that the clinical outcome reaches the requested standards, Eusoma has organised a workshop during which twenty four experts from different disciplines have reviewed the international literature and selected the main process and outcome indicators available for quality assurance of breast cancer care. A review of the literature for evidence-based recommendations have been performed by the steering committee. The experts have identified the quality indicators also taking into account the usability and feasibility. For each of them it has been reported: definition, minimum and target standard, motivation for selection and level of evidence (graded according to AHRO). In overall 17 main quality indicators have been identified, respectively, 7 on diagnosis, 4 on surgery and loco-regional treatment, 2 on systemic treatment and 4 on staging, counselling, follow-up and rehabilitation. Breast Units in Europe are invited to comply with these indicators and monitor them during their periodic audit meetings