Atlas-based Transfer of Boundary Conditions for Biomechanical Simulation

International audienceAn environment composed of different types of living tissues (such as the abdominal cavity) reveals a high complexity of boundary conditions, which are the attachments (e.g. connective tissues, ligaments) connecting different anatomical structures. Together with the material properties, the boundary conditions have a significant influence on the mechanical response of the organs, however corresponding correct me- chanical modeling remains a challenging task, as the connective struc- tures are difficult to identify in certain standard imaging modalities. In this paper, we present a method for automatic modeling of boundary con- ditions in deformable anatomical structures, which is an important step in patient-specific biomechanical simulations. The method is based on a statistical atlas which gathers data defining the connective structures at- tached to the organ of interest. In order to transfer the information stored in the atlas to a specific patient, the atlas is registered to the patient data using a physics-based technique and the resulting boundary conditions are defined according to the mean position and variance available in the atlas. The method is evaluated using abdominal scans of ten patients. The results show that the atlas provides a sufficient information about the boundary conditions which can be reliably transferred to a specific patient. The boundary conditions obtained by the atlas-based transfer show a good match both with actual segmented boundary conditions and in terms of mechanical response of deformable organs

“Geo-Indoor” Design of an indoor navigation app to help elderly people to navigate in buildings

International audienc

The embedded software of an electricity meter: An experience in using Formal Methods in an industrial project

This article presents how various Formal Methods have been involved, first on their own, then coupled, in the different steps of the industrial development of an embedded software for an electricity meter. Synchronized Transition Systems have been used to conceive and implement some Rendezvous mechanisms for the distributed kernel, and the physical link protocol supporting communication between processors. The Rate Monotonic Analysis model has been completed to suit some features of the produc

Multimodal accessibility modeling from coarse transportation networks in Africa

Accessibility is a key driving factor for economic development, social welfare, resources management, and land use planning. In many studies, modeling accessibility relies on proxy variables such as estimated travel time to selected destinations. In developing countries, estimating the travel time is hindered by scarce information about the transportation network, making it necessary to take into account off-network travel coupled with considerations of multimodal options available within the existing network. This research proposes such a hybrid approach that computes the travel time to selected destinations by optimizing together a fully modeled multimodal network and off-network travel. The model was applied in a region around Kisangani located in northeastern Democratic Republic of the Congo. Travel times to Kisangani from the hybrid approach were found to be in close agreement with field-based information (R² = 0.98). The developed approach also proved to better support real-world transportation constraints (such as transfer points between travel modes or barriers) than cost-distance-based travel-time modeling. Demonstration results from the hybrid approach highlight the potential for impact assessment of road construction or rehabilitation, development of secondary towns or markets, and for land use planning in general

Integration of digital imagery for topology optimization

International audienceTo manufacture high-quality products with low manufacturing costs and optimal performance, better design concepts are required. The initial design concept can lead to inefficient structural design and higher manufacturing costs if the topology is not optimal. Topology optimization enables designers to reach their design goals faster, more accurately, and cost-effectively. However, the geometry obtained through topology optimization is not manufacturing-ready due to non-smooth boundaries and gray level images, which require post-processing design implementation by engineers. Various researchers have used different image processing techniques to convert the gray image into a binary map to address this issue. This paper focuses on using image processing to evaluate the differences in optimal designs induced by meshing. This study aims to aid in the parametric understanding of different designs targeting the same application by introducing two new parameters: similarity ratio and conformity ratio. The results compare an optimal geometry obtained using structured and unstructured meshes. Topological optimization algorithms applied to mechanical problems allow for reducing a structure's mass while ensuring its rigidity. However, the final structures may differ for the same problem depending on whether they were meshed regularly or irregularly. This article characterizes the differences between the two final structures using an image processing approach

Toward an integrative organizational framework for outsourced R&D efficiency

International audienceIntegrating Research with Development (R&D) by industrial firms in the early twentieth century was the first step of industrial R&D. Industrial R&D, is nowadays considered as a high resource consumer, in time, money and human work, with a high risk of non-return on investment. Nevertheless R&D divisions are the only way for companies to innovate and keep competitive. So, measuring productivity and added value of R&D division has become a major issue. We are interested in how the R&D articulation allows to convert scientific issues in product prototypes and finally in product innovation. A specific point of interest lays in how an effective measurement framework could improve R&D productivity

Atlas-based Transfer of Boundary Conditions for Biomechanical Simulation

International audienceAn environment composed of different types of living tissues (such as the abdominal cavity) reveals a high complexity of boundary conditions, which are the attachments (e.g. connective tissues, ligaments) connecting different anatomical structures. Together with the material properties, the boundary conditions have a significant influence on the mechanical response of the organs, however corresponding correct me- chanical modeling remains a challenging task, as the connective struc- tures are difficult to identify in certain standard imaging modalities. In this paper, we present a method for automatic modeling of boundary con- ditions in deformable anatomical structures, which is an important step in patient-specific biomechanical simulations. The method is based on a statistical atlas which gathers data defining the connective structures at- tached to the organ of interest. In order to transfer the information stored in the atlas to a specific patient, the atlas is registered to the patient data using a physics-based technique and the resulting boundary conditions are defined according to the mean position and variance available in the atlas. The method is evaluated using abdominal scans of ten patients. The results show that the atlas provides a sufficient information about the boundary conditions which can be reliably transferred to a specific patient. The boundary conditions obtained by the atlas-based transfer show a good match both with actual segmented boundary conditions and in terms of mechanical response of deformable organs