322 research outputs found
Air Traffic Control Tracking Systems Performance Impacts with New Surveillance Technology Sensors
Nowadays, the radar is no longer the only technology able to ensure the surveillance of air traffic. The extensive deployment of satellite systems and air-to-ground data links lead to the emergence of other means and techniques on which a great deal of research and experiments have been carried out over the past ten years. In such an environment, the sensor data processing, which is a key element of an Air Traffic Control center, has been continuously upgraded so as to follow the sensor technology evolution and, at the same time, ensure a more efficient tracking continuity, integrity and accuracy. In this book chapter we propose to measure the impacts of the use of these new technology sensors in the tracking systems currently used for Air Traffic Control applications. The first part of the chapter describes the background of new-technology sensors that are currently used by sensor data processing systems. In addition, a brief definition of internal core tracking algorithms used in sensor data processing components, is given as well as a comparison between their respective advantages and drawbacks. The second part of the chapter focuses on the Multi Sensor Tracking System performance requirements. Investigation regarding the use of Automatic Dependent Surveillance â Broadcast reports and/or with a multi radars configuration, are conducted. The third part deals with the impacts of the âvirtual radarâ or âradar-likeâ approaches that can be used with ADS-B sensors, on the multi sensor tracking system performance. The fourth and last part of the chapter discusses the impacts of sensor data processing performance on sub-sequent safety nets functions that are: ⢠Short term conflict alerts (STCA), ⢠Minimum Safe Altitude Warnings (MSAW), and ⢠Area Proximity Warnings (APW)
Reconstructing human pancreatic differentiation by mapping specific cell populations during development
Report From The Trenches A Case Study In Modernizing Software Development Practices
International audienceOne factor of success in software development companies is their ability to deliver good quality products, fast. For this, they need to improve their software development practices. We work with a medium-sized company modernizing its development practices. The company introduced several practices recommended in agile development. If the benefits of these practices are well documented, the impact of such changes on the developers is less well known. We follow this modernization before and during the COVID-19 outbreak. This paper presents an empirical study of the perceived benefit and drawback of these practices as well as the impact of COVID-19 on the company's employees. One of the conclusions, is the additional difficulties created by obsolete technologies to adapt the technology itself and the development practices it encourages to modern standards
Saint-Pierre – Centre de découverte de la Terre
C’est dans le cadre du projet de construction du Centre de découverte de la Terre, mené et financé par le Conseil général de la Martinique, qu’ont été réalisées les fouilles archéologiques du 27 septembre 2001 au 25 janvier 2002. En effet, le projet, comprenant la réalisation de quatre bâtiments qui présenteront les phénomènes géophysiques ou climatiques les plus spectaculaires, sur le thème du volcanisme, doit s’implanter sur une zone archéologique sensible. L’implantation des édifices porta..
Mapping the Migratory Movements
Based on several conventional geography works and/or artistic works – some of them made by the authors of this paper –, this article focuses on how the mapping of international migrations has evolved since the beginning of the 1990s. The representation of migratory movements, which oscillates between arrows, measurements of stocks and different forms of design, implies both scientific and political stakes for the cartography and geography of migrations. After making a brief recalling of the changes that the mapping of migratory flows has experienced from its origins in the 19th century until today, the authors refer to the main technical and epistemological challenges that cartography of migratory movements and the presentations of itineraries raise nowadays. Finally the article analyses the new cartographic forms that have emerged since the beginning of the 2000s within the interconnected domains of sciences, arts, and militancy.Ă€ partir de diverses rĂ©alisations conventionnelles en gĂ©ographie et/ou artistiques, parmi lesquels des travaux rĂ©alisĂ©s par les auteurs, cet article s’intĂ©resse Ă la manière dont la cartographie des migrations internationales a Ă©voluĂ© depuis le dĂ©but des annĂ©es 1990. La reprĂ©sentation des mouvements migratoires, qui oscille entre des flèches, des mesures de stocks et diverses formes de dessin, soulève autant d’enjeux scientifiques et politiques posĂ©s Ă la cartographie et gĂ©ographie des migrations. Après un bref rappel des changements qu’a connus la cartographie des flux migratoires, depuis ses origines, au XIXe siècle, jusqu’à aujourd’hui, les auteurs Ă©voquent les principaux dĂ©fis techniques et Ă©pistĂ©mologiques que les cartes de flux ou reprĂ©sentant des itinĂ©raires ne cessent de poser. Puis pour terminer, sont prĂ©sentĂ©es de nouvelles formes cartographiques, ayant Ă©mergĂ© depuis le dĂ©but des annĂ©es 2000, dans les domaines croisĂ©s de la science, de l’art et du militantisme.Partiendo de diversos trabajos convencionales de geografĂa y/o artĂsticos – algunos de ellos realizados por los propios autores –, este artĂculo pretende mostrar cĂłmo la cartografĂa de las migraciones internacionales ha ido evolucionando desde principios de los años 1990. La representaciĂłn de los movimientos migratorios, que abarca desde flechas, hasta medidas de reserva y diferentes formas de diseño, supone para la cartografĂa y la geografĂa de las migraciones toda una serie de retos, tanto cientĂficos como polĂticos. Tras hacer un repaso de los cambios que ha ido experimentando la cartografĂa de los flujos migratorios desde sus orĂgenes en el siglo XIX hasta la actualidad, los autores presentan los principales retos tĂ©cnicos y epistemolĂłgicos que los mapas de flujos y las representaciones de itinerarios continĂşan planteando en el momento actual. Por Ăşltimo, se presentan nuevas formas cartográficas surgidas a partir del 2000 que se inscriben en ámbitos interconectados como la ciencia, el arte y el activismo
Similarity learning for person re-identification and semantic video retrieval
Many computer vision problems boil down to the learning of a good visual similarity function that calculates a score of how likely two instances share the same semantic concept. In this thesis, we focus on two problems related to similarity learning: Person Re-Identification, and Semantic Video Retrieval.
Person Re-Identification aims to maintain the identity of an individual in diverse locations through different non-overlapping camera views. Starting with two cameras, we propose a novel visual word co-occurrence based appearance model to measure the similarities between pedestrian images. This model naturally accounts for spatial similarities and variations caused by pose, illumination and configuration changes across camera views. As a generalization to multiple camera views, we introduce the Group Membership Prediction (GMP) problem. The GMP problem involves predicting whether a collection of instances shares the same semantic property. In this context, we propose a novel probability model and introduce latent view-specific and view-shared random variables to jointly account for the view-specific appearance and cross-view similarities among data instances. Our method is tested on various benchmarks demonstrating superior accuracy over state-of-art.
Semantic Video Retrieval seeks to match complex activities in a surveillance video to user described queries. In surveillance scenarios with noise and clutter usually present, visual uncertainties introduced by error-prone low-level detectors, classifiers and trackers compose a significant part of the semantic gap between user defined queries and the archive video. To bridge the gap, we propose a novel probabilistic activity localization formulation that incorporates learning of object attributes, between-object relationships, and object re-identification without activity-level training data. Our experiments demonstrate that the introduction of similarity learning components effectively compensate for noise and error in previous stages, and result in preferable performance on both aerial and ground surveillance videos.
Considering the computational complexity of our similarity learning models, we attempt to develop a way of training complicated models efficiently while remaining good performance. As a proof-of-concept, we propose training deep neural networks for supervised learning of hash codes. With slight changes in the optimization formulation, we could explore the possibilities of incorporating the training framework for Person Re-Identification and related problems.2019-07-09T00:00:00
Metronomic Four-Drug Regimen Has Anti-tumor Activity in Pediatric Low-Grade Glioma; The Results of a Phase II Clinical Trial
Background: Metronomic chemotherapy (MC) is defined as the frequent administration of chemotherapy at doses below the maximal tolerated dose and with no prolonged drug-free break. MC has shown its efficacy in adult tumor types such as breast and ovarian cancer and has to some extent been studied in pediatrics.Objective: To assess the anti-tumor activity and toxicity of a four-drug metronomic regimen in relapsing/refractory pediatric brain tumors (BT) with progression-free survival (PFS) after two cycles as primary endpoint.Methods: Patients ≥4 to 25 years of age were included with progressing BT. Treatment consisted of an 8-week cycle of celecoxib, vinblastine, and cyclophosphamide alternating with methotrexate. Kepner and Chang two-steps model was used with 10 patients in the first stage. If stabilization was observed in ≥2 patients, 8 additional patients were recruited. Assessment was according WHO criteria with central radiology review.Results: Twenty-nine patients (27 evaluable) were included in two groups: ependymoma (group 1, N = 8), and miscellaneous BT (group 2): 3 medulloblastoma (MB), 5 high grade glioma (HGG), 11 low grade glioma (LGG), 2 other BT. After first stage, recruitment for ependymoma was closed [one patient had stable disease (SD) for 4 months]. Cohort 2 was opened for second stage since 1 HGG and 3 LGG patients had SD after two cycles. Recruitment was limited to LGG for the second stage and 2 partial responses (PR), 6 SD and 2 progressive disease (PD) were observed after two cycles. Of these patients with LGG, median age was 10 years, nine patients received vinblastine previously. Median number of cycles was 6.8 (range: 1–12). Treatment was interrupted in five patients for grade 3/4 toxicity.Conclusion: This regimen is active in patients with LGG, even if patients had previously received vinblastine. Toxicity is acceptable.Trial Registration: This study was registered under clinicaltrials.gov – NCT01285817; EUDRACT nr: 2010-021792-81
Impact of donor age over 70 years in donation after circulatory death liver transplantation: a 15 years of experience
peer reviewedBackground: Advanced donor age has been identified as a risk factor in donation after circulatory death (DCD 3) liver transplantation (LT), associated with poor graft function and development of ischemic cholangiopathy. In this study, we evaluated the results after DCD 3 LT using grafts from donors over 70 years compared to younger grafts (<70 years).
Methods: We retrospectively analysed outcome after DCD 3 LT (n=228), comparing donors 70 years (n=53) and <70 years (n=175) from our center between 2003 and 2020. The two age groups were compared in terms of graft and patient survivals at 1, 3 and 5 years, in terms of donor and recipient demographics, transplant conditions and labora- tory values.
Results: The overall graft survivals at 1, 3 and 5 years were 88, 75, 70 per cent respectively. Graft survival rates were not significantly diffe- rent at 5 years between the two groups (P = 0,536). No difference was noted in incidence of acute rejection, biliary strictures, hepatic artery thrombosis or retransplantation rates between the two groups. The time of cold ischemia was significatively lower in the older group (mean 235 min; SD 72) than in younger donor (mean 258 min; SD 72) (p=0.012). The posttransplant AST peak was significatively higher in the advanced age donor group than the second group with 2201±2703 U/L vs 1561U/L (SD 2151±2151 U/L), respectively (p= 0.04).Conclusions: Results for DCD LT from 70-yr-old grafts were similar to those from younger donors. Advanced donors should not be discarded for liver donation if other donor risk factors (such as cold ischemia time and graft quality) are limited
Antimicrobial Stewardship Programs in 13 Belgian hospitals: a survey from the french association of belgian hospital pharmacists
Background: Since 2002, the Belgian Antibiotic Policy Coordibnation Committee (BAPCOC) has supported the development of antimicrobial stewardship (AMS) teams in Belgian hospitals with policy guidance and federal funding. A Royal Decree of 12 February 2008 has consolidated the minimum composition, mandate and tasks of AMS teams. However, between 2017 and 2019, the European Centre for Disease Prevention and Control (ECDC) and the Belgian Health Care Knowledge Centre (KCE) emphasized flaws in our national strategies and policies on antimicrobial resistance. This survey evaluated if the essential and the minimum standards for AMS programs in Belgian hospitals were fulfilled after more than 10 years of activities. Materials/methods: A questionnaire survey was performed based on the international consensus approach developed by Pulcini et al. in 2019. Seven core elements and their related 29 checklist items for global hospital AMS programs were assessed. All the items are weighted identically: 1 point per hospital regardless of the type of hospital or the number of beds. The results are expressed in percentages. Results: Completed questionnaires were provided by 13 hospitals (8 primary, 3 secondary and 2 tertiary hospitals). Figure 1 showed the results of the seven core elements. The core elements number 3 (Available expertise on infection management) and 6 (Monitoring and surveillance) gained good scores. The core elements number 1 (Senior hospital management leadership towards antimicrobial stewardship) and number 7 (Reporting and feedback) have to be improved in the future. The sub-analysis of the 29 items emphasized within the core elements which questions can still be improved. Conclusions: This survey confirmed on the ground what is reflected in the ECDC and KCE reports: the effectiveness of the belgian AMS teams could be improved. This survey could help BAPCOC to easily underline which core elements need improvement
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