Consulta: subjectFacets:"Observers"
Registros recuperados: 4
Data/hora: 07/06/2024 05:04:18

The French experience in sampling discards at sea in the European waters
Provedor de dados: 5
Autores: Tetard, Alain; Gaudou, Olivier; Lespagnol, Patrick; Peronnet, Isabelle; Rochet, Marie-joelle; Vigneau, Joel.
This study covered a one year period using onboard observers (117 days at sea). The aim was to sample "métiers" known for their discarding side effects: fixed netting, inshore and offshore trawling. The objectives were (i) the collection of information on the demographic structure of the catches for the main exploited species and (ii) the identification of factors explaining discards, in order to find relevant management measures
Tipo: Text
Palavras-chave: Celtic Sea; French trawlers; Sampling; Observers; Discard; Metiers; Mer Celtique; Chalutiers français; Échantillonnage; Observateurs; Rejets; Metiers.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/rapport-6129.pdf

Underwater vehicle navigation using diffusion-based trajectory observers
Provedor de dados: 5
Autores: Jouffroy, J; Opderbecke, Jan.
This paper addresses the issue of estimating underwater vehicle trajectories using gyro-Doppler (body-fixed velocities) and acoustic positioning signals (earth-fixed positions). The approach consists of diffusion-based observers processing a whole trajectory segment at a time, allowing the consideration of important practical problems such as different information update rates, outages, and outliers in a very simple framework. Results of contraction theory are used to prove that the observers are convergent, i.e., stable in the incremental sense. Simulation and experimental results are presented to illustrate the potential of application of the method.
Tipo: Text
Palavras-chave: Underwater vehicles; Underwater navigation; Trajectory observers; Trajectory estimation; Observers; Diffusion; Cartography.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-4967.pdf

A non-linear software sensor to monitor the internal nitrogen quota of phytoplanktonic cells
Provedor de dados: 5
Autores: Bernard, O; Sciandra, A; Sallet, G.
New techniques - called software sensors - issued from the non-linear automatic control field and initially developed for non-linear chemical systems have been applied to a continuous culture of phytoplankton. A software sensor (or 'observer') combines an analytical differential equation based model and partial measurements of the system in order to estimate the non-measured state variables. It filters data and estimates the actual state of living systems, models of which are often rough approximations. The efficiency of this approach is illustrated with a nitrate-limited chemostat experiment with the chlorophyceae Dunaliella tertiolecta performed in a computer controlled fluctuating environment. (C) 2001 Ifremer/CNRS/IRD/Editions scientifiques et...
Tipo: Text
Palavras-chave: Modèle de Droop; Systèmes non linéaires; Observateurs; Phytoplancton; Droop model; Non-linear systems; Observers; Phytoplankton.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00322/43340/42888.pdf

Análisis de las capturas de atunes realizadas por dos buques pesqueros de Mar del Plata, Argentina, entre enero y abril de 2010
Provedor de dados: 20
Autores: Garciarena, A.D.
Data obtained by observers on board of two fishing vessels during six trips carried out between January-April 2010 to catch tuna were analyzed. Thirty-four fishing days were completed and of the 59 trawls performed 37 turned out positive (with tuna catches). The fishing gear consisted of a purse seine net. Exploitation took place within the Argentine-Uruguayan Common Fishing Zone, between 36° S-39° S. The main landings occurred in March and consisted of slender tuna, Allothunnus fallai (57%), followed by albacore, Thunnus alalunga (28.5%), in January and bonito, Sarda sarda (14%), in April. Sea surface temperature ranged 16 °C-19 °C. A total of 25 length frequency samples allowed to measure individuals of the species above mentioned and those of skipjack...
Tipo: Journal Contribution
Palavras-chave: Tuna fisheries; Catch statistics; Commercial fishing; Allothunnus fallai; Thunnus alalunga; Sarda sarda; Observers; Marine environment.
Ano: 2011
URL: http://hdl.handle.net/1834/4882