Decoupled Sampling-Based Motion Planning for Multiple Autonomous Marine Vehicles

There is increasing interest in the deployment and operation of multiple autonomous marine vehicles (AMVs) for a number of challenging scientific and commercial operational mission scenarios. Some of the missions, such as geotechnical surveying and 3D marine habitat mapping, require that a number of heterogeneous vehicles operate simultaneously in small areas, often in close proximity of each other. In these circumstances safety, reliability, and efficient multiple vehicle operation are key ingredients for mission success. Additionally, the deployment and operation of multiple AMVs at sea are extremely costly in terms of the logistics and human resources required for mission supervision, often during extended periods of time. These costs can be greatly minimized by automating the deployment and initial steering of a vehicle fleet to a predetermined configuration, in preparation for the ensuing mission, taking into account operational constraints. This is one of the core issues addressed in the scope of the Widely Scalable Mobile Underwater Sonar Technology project (WiMUST), an EU Horizon 2020 initiative for underwater robotics research. WiMUST uses a team of cooperative autonomous ma- rine robots, some of which towing streamers equipped with hydrophones, acting as intelligent sensing and communicat- ing nodes of a reconfigurable moving acoustic network. In WiMUST, the AMVs maintain a fixed geometric formation through cooperative navigation and motion control. Formation initialization requires that all the AMVs start from scattered positions in the water and maneuver so as to arrive at required target configuration points at the same time in a completely au- tomatic manner. This paper describes the decoupled prioritized vehicle motion planner developed in the scope of WiMUST that, together with an existing system for trajectory tracking, affords a fleet of vehicles the above capabilities, while ensuring inter- vehicle collision and streamer entanglement avoidance. Tests with a fleet of seven marine vehicles show the efficacy of the system planner developed.Peer reviewe

A year-round measurement of water-soluble trace and rare earth elements in arctic aerosol: Possible inorganic tracers of specific events

This study presents the year-round variability of the water-soluble fraction of trace elements (wsTE) and rare earth elements (wsREE) among size segregated airborne particulate matter samples collected at Ny-Å lesund in the Svalbard Archipelago from 26 February 2018 to 26 February 2019. Six different aerosol dimensional fractions were collected using a multi-stage Andersen impactor to better understand local and global circulation with the aim of disentangling the source of inorganic tracers from specific natural or anthropogenic sources. The wsTE and wsREE content, especially in the finest fractions in remote areas, is primarily related to long-range transport and it gives valuable information on (1) the global circulation, (2) the natural sources and (3) the contribution of human activities to aerosol composition. A Factor Analysis was applied to the dataset, including levoglucosan and methanesulfonic acid (MSA), to assess the possibility of using certain inorganic tracers as indicators of specific transport events or circulation regimes. We also investigate back-trajectories to determine potential source areas

Food and biofuel: a possible dialogue? An overview about brazilian ethanol context.

Tropentag 2015

Modelo de agricultura familiar para o entorno da Central Geradora Termelétrica Fortaleza (CGTF) em Caucaia, CE.

No presente artigo será apresentado uma proposta de modelo de agricultura familiar, com base na caracterização socioambiental da área e na percepção dos agricultores.bitstream/item/24612/1/circtec44-2010-modelo-agricultura-familiar-ceara.pd

Mapeamento de uso e cobertura da terra de uma bacia de drenagem no Bioma Mata Atlântica com uso de imagem de alta resolução.

A proteção da natureza não é um fenômeno exclusivo dos dias atuais. A preocupação com a preservação dos recursos naturais já se constituía em um desafio para as sociedades antigas. O desenvolvimento de técnicas de sensoriamento remoto e geoprocessamento contribuem sobremaneira com esse objetivo, tendo em vista a possibilidade de avaliações de uso e cobertura das terras nas mais diversas escalas de análise. O presente trabalho teve como objetivo mapear o uso e cobertura da terra de uma bacia de área de montanha no Rio de Janeiro, utilizando-se uma imagem de alta resolução do ano de 2010. Pretende-se, nesse trabalho, apresentar resultados referentes ao mapeamento no ano de 2010 e compará-lo com o mapeamento já realizado na área, no ano de 2004, e assim caracterizar as mudanças de uso e cobertura da terra na bacia.bitstream/item/141895/1/BPD-229-Mapeamento-Uso.pd

Ferramentas para avaliação do potencial à prestação de serviços ambientais pelo Sistema Plantio Direto.

A presente publicação tem como objetivo apresentar algumas ferramentas utilizadas e com potencial para a verificação da qualidade do sistema de plantio direto praticado nas propriedades rurais e como o resultado de tais ferramentas pode ser utilizado como incentivo ao pagamento de serviços ambientais (PSA).bitstream/item/166343/1/CNPS-ComTec-75-2017.pd

To methylate or not to methylate? Study of Mercury Speciation along\ud the Venetian Littoral System (Q-ALiVe project)

The biogeochemical cycle of mercury (Hg) is affected not only by the physical, chemical and hydrological characteristics of the environment, but also by changes in productivity and biodiversity. In waters the complexes of Hg are related to the salinity and to the load of dissolved organic carbon (DOC) in the dissolved and in the particulate phases. Surface and bottom seawater were sampled along the Venetian coast at ten sites with different characteristics. Samples were analyzed employing hyphenated techniques and LOD (limit of detection) and LOQ (limit of quantification) were quantified. Although for some samples both the species were under the LOQ, the presence of methyl mercury (CH3Hg+) and ionic mercury (Hg2+) at the same time in surface and in bottom waters were observed. Variability in CH3Hg+ concentrations may be due to changes in the phytoplankton communities, which in turn may be affected by nutrient loads from the catchment area and port mouths of the Venice Lagoon. Thus, monitoring these nutrient loads may be essential for the health of the Venetian littoral system, since they may affect blooms, methylation and hyper-bioaccumulation along the trophic web, with effects on the environment and on human health