1,185 research outputs found

    An Abstract Module Concept for Graph Transformation Systems

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    Graph transformation systems are a well known formal specification technique that support the rule based specification of the dynamic behaviour of systems. Recently, many specification languages for graph transformation systems have been developed, and modularization techniques are then needed in order to deal with large and complex graph transformation specifications, to enhance the reuse of specifications, and to hide implementation details. In this paper we present an abstract categorical approach to modularization of graph transformation systems. Modules are called cat–modules and defined over a generic category cat of graph transformation specifications and morphisms. We describe the main characteristics and properties of cat–modules, their interconnection operations, namely union, composition and refinement of modules, and some compatibility properties between such operations

    Functional adaptivity for digital library services in e-infrastructures: the gCube approach

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    We consider the problem of e-Infrastructures that wish to reconcile the generality of their services with the bespoke requirements of diverse user communities. We motivate the requirement of functional adaptivity in the context of gCube, a service-based system that integrates Grid and Digital Library technologies to deploy, operate, and monitor Virtual Research Environments deïŹned over infrastructural resources. We argue that adaptivity requires mapping service interfaces onto multiple implementations, truly alternative interpretations of the same functionality. We then analyse two design solutions in which the alternative implementations are, respectively, full-ïŹ‚edged services and local components of a single service. We associate the latter with lower development costs and increased binding ïŹ‚exibility, and outline a strategy to deploy them dynamically as the payload of service plugins. The result is an infrastructure in which services exhibit multiple behaviours, know how to select the most appropriate behaviour, and can seamlessly learn new behaviours

    Collective Effects of Fire Intensity and Sloped Terrain on Wind-Driven Surface Fire and Its Impact on a Cubic Structure

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    The combined effects of percent slope and fire intensity of a wind driven line fire on an idealized building has been numerically investigated in this paper. The simulations were done using the large eddy simulation (LES) solver of an open source CFD toolbox called FireFOAM. A set of three fire intensity values representing different heat release rates of grassland fuels on different inclined fuel beds have been modeled to analyze the impact of factors, such as fuel and topography on wind-fire interaction of a built area. An idealized cubic structure representing a simplified building was considered downstream of the fire source. The numerical results have been verified with the aerodynamic measurements of a full-scale building model in the absence of fire effects. There is a fair consistency between the modeled findings and empirical outcomes with maximum error of 18%, which acknowledge the validity and precision of the proposed model. The results show that concurrent increase of fire intensity and terrain slope causes an expansion of the surface temperature of the building which is partially due to the increase of flame tilt angle upslope on the hilly terrains. In addition, increasing fire intensity leads to an increase in the flow velocity, which is associated with the low-pressure area observed behind the fire front. Despite limitations of the experimental results in the area of wind-fire interaction the result of the present work is an attempt to shed light on this very important problem of fire behavior prediction. This article is a primary report on this subject in CFD modeling of the collective effects of fire intensity and sloped terrain on wind driven wildfire and its interaction on buildings

    A graphical approach to relational reasoning

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    Relational reasoning is concerned with relations over an unspecified domain of discourse. Two limitations to which it is customarily subject are: only dyadic relations are taken into account; all formulas are equations, having the same expressive power as first-order sentences in three variables. The relational formalism inherits from the Peirce-Schröder tradition, through contributions of Tarski and many others. Algebraic manipulation of relational expressions (equations in particular) is much less natural than developing inferences in first-order logic; it may in fact appear to be overly machine-oriented for direct hand-based exploitation. The situation radically changes when one resorts to a convenient representation of relations based on labeled graphs. The paper provides details of this representation, which abstracts w.r.t. inessential features of expressions. Formal techniques illustrating three uses of the graph representation of relations are discussed: one technique deals with translating first-order specifications into the calculus of relations; another one, with inferring equalities within this calculus with the aid of convenient diagram-rewriting rules; a third one with checking, in the specialized framework of set theory, the definability of particular set operations. Examples of use of these techniques are produced; moreover, a promising approach to mechanization of graphical relational reasoning is outlined

    Patch end-Launchers-a family of compact colinear coaxial-to-rectangular waveguide transitions

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    Evaluating the environmental and economic impact of fruit and vegetable waste valorisation: The lettuce waste study-case

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    The fruit and vegetable sector generates large amounts of waste, which poses both environmental and economic issues. Different strategies can be applied to valorise fruit and vegetable waste (FVW) by turning it into value-added products. However, the economic and environmental impact of such strategies is largely unknown. In this paper, the environmental and economic impact of FVW valorisation on an industrial scale was evaluated by developing a Decision Support System (DSS). To this aim, the lettuce waste study-case was considered, since different innovative laboratory-scale strategies have been recently proposed for its valorisation. Investment and running costs, energetic demand and yields of lettuce waste valorisation processes were collected based on laboratory tests and industrial surveys. The application of the DSS estimated that if 30% of lettuce waste annually produced by a large company was valorised by using a system configuration that involves not only anaerobic digestion and composting, but also high pressure homogenisation to produce fresh juices, and ultrasound-assisted extraction to produce antioxidant extracts, this configuration would lead to an investment lower than 10 million \u20ac, a 1 year-pay-back time and a 72 tons-reduction of carbon dioxide emissions, thus representing a rational compromise between economic returns and environmental advantage. The developed multi-objective DSS is a valuable tool to identify the most sustainable and investment-worthy processes for the valorisation of FVW

    Programa de gerenciamento de resĂ­duos da Embrapa Florestas.

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    bitstream/CNPF-2009-09/41246/1/Doc_119.pd

    Changes in the Excitability of Corticobulbar Projections Due to Intraoral Cooling with Ice

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    The aim of this study was to assess the effects of ice applied to the oral cavity on the excitability of corticobulbar projections to the swallowing muscles. The subjects were 8 healthy adult volunteers (mean age 29.0 ± 4.9 years). Motor-evoked potentials (MEPs) were recorded from the suprahyoid muscle complex using surface electrodes. Two blocks of 20 MEPs with a test stimulus intensity of 120% of the resting motor threshold were recorded at rest (baseline). Subjects then underwent 5-min thermal stimulation by either of 3 different types: (1) "ice-stick inside mouth," (2) "ice-stick on neck," and (3) "room temperature inside mouth." Blocks of 20 MEPs were then recorded immediately and at 5-min intervals for the following 15 min. There was a significant difference in the effects of the 3 interventions on the amplitude of the MEPs following stimulation (two-way ANOVA: INTERVENTION × TIME; F8,84 = 3.76, p < 0.01). One-way ANOVA was used to evaluate the changes over time for each intervention type. Only "ice-stick inside mouth" caused an increase in the MEPs (one-way ANOVA main effect of TIME: F4,28 = 4.04, p = 0.010) with significant differences between baseline and P10 (mean difference 0.050; confidence interval (CI) 95% 0.019-0.079; p = 0.004). There were no significant effects of either "ice-stick on neck" or "room temperature inside mouth" (F4,28 = 1.13, p = 0.36; F4,28 = 1.36, p = 0.27, respectively). Ice stimulation within the oral cavity increases the excitability of the cortical swallowing motor pathway
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