Search results for "LITERATURE"
showing 10 items of 7441 documents
Vision based attitude and altitude estimation for UAVs in dark environments
2011
This paper presents a system dedicated to the real-time estimation of attitude and altitude for unmanned aerial vehicles (UAV) under low light and dark environment. This system consists in a fisheye camera, which allows to cover a large field of view (FOV), and a laser circle projector mounted on a fixed baseline. The approach, close to structured light systems, uses the geometrical information obtained by the projection of the laser circle onto the ground plane and perceived by the camera. We present a theoretical study of the system in which the camera is modelled as a sphere and show that the estimation of a conic on this sphere allows to obtain the attitude and the altitude of the robot…
Omnidirectional vision for UAV: applications to attitude, motion and altitude estimation for day and night conditions
2012
International audience; This paper presents the combined applications of omnidirectional vision featuring on its application to aerial robotics. Omnidirectional vision is first used to compute the attitude, altitude and motion not only in rural environment but also in the urban space. Secondly, a combination of omnidirectional and perspective cameras permits to estimate the altitude. Finally we present a stereo system consisting of an omnidirectional camera with a laser pattern projector enables to calculate the altitude and attitude during the improperly illuminated conditions to dark environments. We demonstrate that omnidirectional camera in conjunction with other sensors is suitable cho…
Simulated 3-axis versus 5-axis Processing Toolpaths for Single Point Incremental Forming
2019
Abstract Accuracy and productivity of the parts manufactured by single point incremental forming (SPIF) are influenced by the proper selection of toolpaths. CAM software packages are often used for generating the toolpaths for the process. Literature survey have revealed that contour curves and spatial spirals are the most used toolpaths for SPIF. These toolpaths are generated using 3-axis approaches, meaning that the tool axis is maintained parallel to the vertical axis. The 3-axis approach was justified using 3-axis CNC milling machines as the main technological equipment for SPIF. However, nowadays, the wide spreading of both 5-axis CNC milling machines and industrial robots, with far su…
Propulsion monitoring system for digitized ship management: Preliminary results from a case study
2020
Abstract The paradigm of Industry 4.0 a fundamental driver of innovation in marine industry, where the new digital era will see the development of smart cyber-ships equipped with advanced automation systems that will progressively evolve towards fully autonomous vessels. Although the journey towards such technological frontier has started, most companies operating in the maritime sector still appear un-prepared to face the future scenario. In the maritime sector, in fact, empirical models and oversimplified approaches are still largely employed for the management of fleet operations. There is thus the necessity of developing and providing operative models for digitized ship management, whic…
Creating a questionnaire for a scientific study
2016
Using questionnaires has become a permanent part of collecting data in scientific studies within the sphere of human sciences as well as other disciplines. It has been utilized already for nearly a century in collecting data. The first questionnaires were carried out on paper but nowadays there are e-questionnaires alongside it which can be carried out through e-mail or published on a social media platform (for example, Facebook). An often used method is also a survey which is carried out with a research project's own web page, association or company etc. A questionnaire has been considered as an actual scientific method of data collection since 1930s. However, it was already used a little …
Terrorism communication : characteristics and emerging perspectives in the scientific literature 2002–2011
2013
This paper aims to clarify current knowledge on the contribution of communication to crisis management in the case of terrorism incidents. This is done by means of a systematic review of the scientific literature on terrorism communication over the last 10 years to identify the many challenges facing communication in such crises, and represents the first attempt of its kind. To date, within the literature on terrorism communication, much attention has been paid to chemical, biological, radiological or nuclear hazards. Terrorism crises are complex and challenging. Preparedness for such diverse low-probability high-impact crises can best be included in a wider educative approach. Terrorism cr…
Bioprospecting challenges in unusual environments
2017
Editorial: The microbiome as a source of new enterprises and job creation.
Impact des facteurs nutritionnels pendant et après cancer
2021
Nutritional factors (diet, weight, alcohol, physical activity) are identified as factors having an impact on the onset of several cancer sites. Less abundant scientific data also underline their impact on the tumor progression. A review of the scientific literature was carried out by a group of experts established by the French National Cancer Institute (INCa) to better document the influence of nutritional factors during and after cancer on outcomes such as overall mortality, cancer specific mortality, recurrence, second primary cancers and quality of life. This analysis of the literature completes messages of reduction of alcohol consumption, prevention of undernutrition or excess weight …
Oligodendrocytes control potassium accumulation in white matter and seizure susceptibility
2018
Oligodendrocytes Control Potassium Accumulation in White Matter and Seizure Susceptibility.Larson VA, Mironova Y, Vanderpool KG, Waisman A, Rash JE, Agarwal A, Bergles DE. Elife. 2018 Mar 29;7. pii: e34829. doi: 10.7554/eLife.34829.The inwardly rectifying K+ channel Kir4.1 is broadly expressed by central nervous system glia and deficits in Kir4.1 lead to seizures and myelin vacuolization. However, the role of oligodendrocyte Kir4.1 channels in controlling myelination and K+ clearance in white matter has not been defined. Here, we show that selective deletion of Kir4.1 from oligodendrocyte progenitors or mature oligodendrocytes did not impair their development or disrupt the structure of mye…
The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses
2018
Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documented for many bacteria. However, the role of nitrogen-fixing methanotrophs in nitrogen supply to Sphagnum peat mosses is not well explored. Here, we investigated the role of both oxygen and methane on nitrogen fixation in subarctic Sphagnum peat mosses. Five species of Sphagnum mosses were sampled from two mesotrophic and three oligotrophic sites within the Lakkasuo peatland in Orivesi, central Finland. Mo…