56 research outputs found

    BigraphER: rewriting and analysis engine for bigraphs

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    BigraphER is a suite of open-source tools providing an effi- cient implementation of rewriting, simulation, and visualisation for bigraphs, a universal formalism for modelling interacting systems that evolve in time and space and first introduced by Milner. BigraphER consists of an OCaml library that provides programming interfaces for the manipulation of bigraphs, their constituents and reaction rules, and a command-line tool capable of simulating Bigraphical Reactive Systems (BRSs) and computing their transition systems. Other features are native support for both bigraphs and bigraphs with sharing, stochastic reaction rules, rule priorities, instantiation maps, parameterised controls, predicate checking, graphical output and integration with the probabilistic model checker PRISM

    Finite Models for a Spatial Logic with Discrete and Topological Path Operators

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    This paper analyses models of a spatial logic with path operators based on the class of neighbourhood spaces, also called pretopological or closure spaces, a generalisation of topological spaces. For this purpose, we distinguish two dimensions: the type of spaces on which models are built, and the type of allowed paths. For the spaces, we investigate general neighbourhood spaces and the subclass of quasi-discrete spaces, which closely resemble graphs. For the paths, we analyse the cases of quasi-discrete paths, which consist of an enumeration of points, and topological paths, based on the unit interval. We show that the logic admits finite models over quasi-discrete spaces, both with quasi-discrete and topological paths. Finally, we prove that for general neighbourhood spaces, the logic does not have the finite model property, either for quasi-discrete or topological paths

    Inventário Florístico Florestal de Santa Catarina: espécies da Floresta Estacional Decidual.

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    O presente trabalho visou apresentar e analisar a flora da Floresta Estacional Decidual em Santa Catarina, Brasil, tendo como fonte de dados os levantamentos realizados durante o Inventário Florístico Florestal de Santa Catarina. Foram avaliadas as espécies de indivíduos lenhosos de 79 unidades amostrais de 4.000 m². Foram feitas coletas extras de indivíduos férteis, no entorno e nas unidades amostrais, das demais formas de vida. Este esforço amostral registrou 420 espécies, abrangendo 90 famílias e 275 gêneros. Nas unidades amostrais, registrou-se 233 espécies, sendo 204 com diâmetro na altura do peito (DAP) ? 10 cm e 162 com diâmetro na altura do peito DAP ? 10 cm e altura ? 1,50 m, portanto com espécies em comuns. A coleta de material extra registrou 332 angiospermas e uma gimnosperma (Araucaria angustifolia), demonstrando a importância de coletas externas às áreas previamente delimitadas. Entre as ameaçadas de extinção foram registradas Ocotea odorifera e Araucaria angustifolia

    Floristic and forest inventory of Santa Catarina: species of evergreen rainforest.

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    O presente trabalho objetivou apresentar a lista de espécies da floresta pluvial subtropical (Floresta Ombrófila Densa) em Santa Catarina, com base em 202 unidades amostrais implantadas pelo Inventário Florístico Florestal de Santa Catarina para estudo do componente arbóreo-arbustivo e da regeneração, além de coletas florísticas externas às unidades amostrais. Foram registradas 1.473espécies, 19,0% das espécies citadas para esta tipologia florestal no Brasil, dentre estas três gimnospermas e 1.470 angiospermas. As famílias mais ricas em espécies foram: Orchidaceae (143 espécies), Myrtaceae (142), Asteraceae (98), Melastomataceae (86), Fabaceae (78), Rubiaceae (65), Solanaceae (61), Bromeliaceae (57), Piperaceae (56) e Lauraceae (52). Entre as espécies registradas, oito constam na Lista Oficial das Espécies da Flora Brasileira Ameaçadas de Extinção: Aechmea blumenavii, Araucaria angustifolia, Billbergia alfonsijoannis, Euterpe edulis, Heliconia farinosa, Ocotea catharinensis, O. odorifera e O. porosa

    Conditional Bigraphs

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    Bigraphs are a universal graph based model, designed for analysing reactive systems that include spatial and non-spatial (e.g. communication) relationships. Bigraphs evolve over time using a rewriting framework that finds instances of a (sub)-bigraph, and substitutes a new bigraph. In standard bigraphs, the applicability of a rewrite rule is determined completely by a local match and does not allow any non-local reasoning, i.e. contextual conditions. We introduce conditional bigraphs that add conditions to rules and show how these fit into the matching framework for standard bigraphs. An implementation is provided, along with a set of examples. Finally, we discuss the limits of application conditions within the existing matching framework and present ways to extend the range of conditions that may be expressed

    On lions, impala, and bigraphs: modelling interactions in physical/virtual spaces

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    While HCI has a long tradition of formally modelling task-based interactions with graphical user interfaces, there has been less progress in modelling emerging ubiquitous computing systems due in large part to their highly contextual nature and dependence on unreliable sensing systems. We present an exploration of modelling an example ubiquitous system, the Savannah game, using the mathematical formalism of bigraphs, which are based on a universal process algebra that encapsulates both dynamic and spatial behaviour of autonomous agents that interact and move among each other, or within each other. We establish a modelling approach based on four perspectives on ubiquitous systems—Computational, Physical, Human, and Technology—and explore how these interact with one another. We show how our model explains observed inconsistencies in user trials of Savannah, and then, how formal analysis reveals an incompleteness in design and guides extensions of the model and/or possible system re-design to resolve this

    Structure of mixed ombrophyllous forests with Araucaria angustifolia (Araucariaceae) under external stress in Southern Brazil.

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    This study is part of the Floristic and Forest Inventory of Santa Catarina, conceived to evaluate forest resources, species composition and structure of forest remnants, providing information to update forest conservation and land use policy in Southern Brazilian State of Santa Catarina (95 000km²). In accordance to the Brazilian National Forest Inventory (IFN-BR), the inventory applies systematic sampling, with 440 clusters containing four crosswise 1 000m² plots (20x50m) each, located on a 10x10km grid overlaid to land use map based on classification of SPOT-4 images from 2005. Within the sample units, all woody individuals of the main stratum (DBH?10cm) are measured and collected (fertile and sterile), if not undoubtedly identified in field. Regeneration stratum (height>1.50m; DBH<10cm) is registered in 100m² in each sample unit. Floristic sampling includes collection of all fertile trees, shrubs and herbs within the sample unit and in its surroundings. This study performs analysis based on 92 clusters measured in 2008 within an area of 32 320km² of mixed ombrophyllous forests with Araucaria angustifolia located at the state’s high plateau (500m to 1 560m above sea level at 26º00’-28º30’ S and 49º13’-51º23’ W). Mean density (DBH?10cm) is 578 individuals/ha (ranging from 85/ha to 1 310/ha), mean species richness in measured remnants is 35 (8 to 62), Shannon and Wiener diversity index (H’) varies between 1.05 and 3.48. Despite high total species diversity (364 Magnoliophyta, five Coniferophyta and one tree fern) and relatively high mean basal area (25.75m²/ha, varying from 3.87 to 68.85m²/ ha), the overwhelming majority of forest fragments are considered highly impacted and impoverished, mostly by logging, burning and extensive cattle farming, turning necessary more efficient protection measures. Basal area was considered an appropriate indicator for stand quality and conservation status

    Epífitos vasculares da floresta ombrófila densa de Santa Catarina.

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    Esse trabalho objetiva demonstrar a ocorrência dos epífitos vasculares da Floresta Ombrófila Densa de Santa Catarina

    Riqueza de epífitos vasculares do Parque Nacional da Serra do Itajaí - Santa Catarina.

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    Este trabalho objetivou contribuir para a caracterização da comunidade epifítica vascular no Parque Nacional da Serra do Itajaí, Vale do Itajaí, Santa Catarina
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