Algorithme de segmentation large échelle pour l'analyse orientée objet

International audienceThe amount of remote sensing images is constantly growing due to the increasing amount of satellites with Very High Resolution or very short revisiting time. In this context, exact large scale OBIA segmentation algorithms have been proposed to process remote sensing images of arbitrary size , to overcome the memory limitation issue. It is important to note that in this context, The word _exact_ means that algorithms ensure resulting segments to be identical to those obtained without tiling, while using a tiling strategy with a proper stability margin. However those solutions have been proposed for sequential execution, and current implementations can use only one single processing unit on one single computer. Thus the execution time can be very important, which still prevents those approaches to be used for OBIA processing in an operational context. Meanwhile, resorting to High Performance Computing (HPC) is becoming a common practice to tackle the computational complexity in Earth Observation information extraction, since it provides environments and programming facilities able to speed-up processes. In this paper, we focus on the parallelization of segmentation algorithms to process large images in a reasonable time, using HPC techniques. Our approach consists in a generic strategy of parallelization using the Message Passing Interface (MPI) standard with the concept of remote window. While MPI enables the scaling through multiple processing nodes, threaded parallelism is used in the shared memory context to optimize core algorithms. A specific attention has also been paid to IO operations which is a well known bottleneck in HPC environments. We have successfully applied our method to two state of the art segmentation algorithms commonly used in remote sensing images processing, namely the Generic Region Merging and the Mean Shift Smoothing based segmentation. The hybrid distributed-shared memory approach enables algorithms to benefit from both multiple CPUs of one processing node, and also multiple nodes connected through network thank to the MPI. As our aim is to enable those algorithms for operational applications, we have implemented our approach for the two segmentation algorithms cited above in the Orfeo ToolBox, a well known open-source library for geospatial images processing. In the final paper and presentation, trends of execution times for different configurations of real remote sensing input data and HPC ressources will be presented and discussed. The source code corresponding to the application presented in this paper is available for download, and will be integrated in the forthcoming releases of the Orfeo Toolbox. 34 diapos

Clinical utility of pembrolizumab in the management of advanced solid tumors: an evidence-based review on the emerging new data

Pauline du Rusquec, Ombline de Calbiac, Marie Robert, Mario Campone, Jean Sebastien FrenelMedical Oncology Department, Institut de Cancérologie de l’Ouest, Saint-Herblain 44800, FranceAbstract: Pembrolizumab is a full-length human immunoglobulin G4 (IgG4) monoclonal antibody directed against the immune checkpoint PD-1 to remove its binding with PD-L1 and thus to restore an anti-tumor immune response of T cells. Pembrolizumab is one of the most advanced immune checkpoint inhibitors for cancer care. Apart from rare and serious adverse effects, its favorable tolerance profile enables to treat fragile patients who have often no other choice than best supportive care. The effective retained dose of pembrolizumab is a venous administration of 200 mg every 3 weeks until disease progression, intolerance or up to 24 months. Pembrolizumab has already proven its efficacy and thus obtained marketing authorization in so-called hot or hypermutated tumors or tumors expressing PD-L1 such as melanomas, non-small cell lung cancers, urothelial carcinomas, cervical cancer, etc. Pembrolizumab is also authorized in the United States in the treatment of mismatch repair-deficient tumors or with microsatellite instability. The current challenge is to expand its use in tumor types that are supposed to be less immunogenic, for example, by attempting to warm up the tumor microenvironment, or by combining pembrolizumab with other molecules. An acceptable toxicity profile of such combinations remains to explore. We review here the current indications of this drug, the main prognostic and predictive factors of its efficacy as well as the potential forthcoming indications.Keywords: pembrolizumab, immune checkpoint inhibitor, anti PD-1 antibod

Les actualités marquantes du congrès Targeted Anticancer Therapies — TAT 2016

International audienc

Targeted anticancer therapies — TAT Congress, 2016

International audienc

1158P Study of patients’ characteristics associated with osimertinib outcomes upfront or in following lines in EGFR-positive NSCLC

BACKGROUND : In first line (L1) for EGFR-mutated (mEGFR) advanced NSCLC (aNSCLC), osimertinib (osi) has been the preferred option since 2018. First generation anti-EGFR TKI (1G) alone followed by osi, or 1G + anti-angiogenic or 1G + chemotherapy are other options. We aimed to assess the subgroups of patients (pts) that do not benefit from 1G alone compared with osimertinib L1 in mEGFR aNSCLC. [...