94 research outputs found
Runtime Verification of Temporal Patterns for Dynamic Reconfigurations of Components
International audienceDynamic reconfigurations increase the availability and the reliability of component-based systems by allowing their architectures to evolve at runtime. Recently we have proposed a temporal pattern logic, called FTPL, to characterize the correct reconfigurations of component-based systems under some temporal and architectural constraints. As component-based architectures evolve at runtime, there is a need to check these FTPL constraints on the fly, even if only a partial information is expected. Firstly, given a generic component-based model, we review FTPL from a runtime verification point of view. To this end we introduce a new four-valued logic, called RV-FTPL (Runtime Verification for FTPL), characterizing the "potential" (un)satisfiability of the architectural constraints in addition to the basic FTPL semantics. Potential true and potential false values are chosen whenever an observed behaviour has not yet lead to a violation or satisfiability of the property under consideration. Secondly, we present a prototype developed to check at runtime the satisfiability of RV-FTPL formulas when reconfiguring a Fractal component-based system. The feasability of a runtime property enforcement is also shown. It consists in supervising on the fly the reconfiguration execution against desired RV-FTPL properties. The main contributions are illustrated on the example of a HTTP server architecture
Non-destructive analysis of museum objects by fibre-optic Raman spectroscopy
Raman spectroscopy is a versatile technique that has frequently been applied for the investigation of art objects. By using mobile Raman instrumentation it is possible to investigate the artworks without the need for sampling. This work evaluates the use of a dedicated mobile spectrometer for the investigation of a range of museum objects in museums in Scotland, including antique Egyptian sarcophagi, a panel painting, painted surfaces on paper and textile, and the painted lid and soundboard of an early keyboard instrument. The investigations of these artefacts illustrate some analytical challenges that arise when analysing museum objects, including fluorescing varnish layers, ambient sunlight, large dimensions of artefacts and the need to handle fragile objects with care. Analysis of the musical instrument (the Mar virginals) was undertaken in the exhibition gallery, while on display, which meant that interaction with the public and health and safety issues had to be taken into account. [Figure: see text
Vaccination against Bm86 Homologues in Rabbits Does Not Impair Ixodes ricinus Feeding or Oviposition
Human tick-borne diseases that are transmitted by Ixodes ricinus, such as Lyme
borreliosis and tick borne encephalitis, are on the rise in Europe.
Diminishing I. ricinus populations in nature can reduce tick exposure to
humans, and one way to do so is by developing an anti-vector vaccine against
tick antigens. Currently, there is only one anti-vector vaccine available
against ticks, which is a veterinary vaccine based on the tick antigen Bm86 in
the gut of Rhipicephalus microplus. Bm86 vaccine formulations cause a
reduction in the number of Rhipicephalus microplus ticks that successfully
feed, i.e. lower engorgement weights and a decrease in the number of
oviposited eggs. Furthermore, Bm86 vaccines reduce transmission of bovine
Babesia spp. Previously two conserved Bm86 homologues in I. ricinus ticks,
designated as Ir86-1 and Ir86-2, were described. Here we investigated the
effect of a vaccine against recombinant Ir86-1, Ir86-2 or a combination of
both on Ixodes ricinus feeding. Recombinant Ixodes ricinus Bm86 homologues
were expressed in a Drosophila expression system and rabbits were immunized
with rIr86-1, rIr86-2, a combination of both or ovalbumin as a control. Each
animal was infested with 50 female adults and 50 male adults Ixodes ricinus
and tick mortality, engorgement weights and egg mass were analyzed. Although
serum IgG titers against rIr86 proteins were elicited, no effect was found on
tick feeding between the rIr86 vaccinated animals and ovalbumin vaccinated
animals. We conclude that vaccination against Bm86 homologues in Ixodes
ricinus is not an effective approach to control Ixodes ricinus populations,
despite the clear effects of Bm86 vaccination against Rhipicephalus microplus
Geometric techniques for implicit two-dimensional systems
Geometric tools are developed for two-dimensional (2-D) models in an implicitFornasiniâMarchesini form. In particular, the structural properties of controlled and conditionedinvariance are defined and studied. These properties are investigated in terms ofquarter-plane causal solutions of the implicit model given compatible boundary conditions.The definitions of controlled and conditioned invariance introduced, along with the correspondingoutput-nulling and input-containing subspaces, are shown to be richer than theone-dimensional counterparts. The analysis carried out in this paper establishes necessaryand sufficient conditions for the solvability of 2-D disturbance decoupling problems andunknown-input observation problems. The conditions obtained are expressed in terms ofoutput-nulling and input-containing subspaces, which can be computed recursively in a finitenumber of steps
Detectability subspaces and observer synthesis for two-dimensional systems
The notions of input-containing and detectability subspaces are developed within the context of observer synthesis for two-dimensional (2-D) Fornasini-Marchesini models. Specifically, the paper considers observers which asymptotically estimate the local state, in the sense that the error tends to zero as the reconstructed local state evolves away from possibly mismatched boundary values, modulo a detectability subspace. Ultimately, the synthesis of such observers in the absence of explicit input information is addressed
Implementation of behavioral systems
In this chapter, we study control by interconnection of a given linear
differential system (the plant behavior) with a suitable controller. The problem formulations
and their solutions are completely representation free, and specified only
in terms of the system dynamics. A controller is a system that constrains the plant
behavior through a certain set of variables. In this context, there are two main situations
to be considered: either all the system variables are available for control, i.e.,
are control variables (full control) or only some of the variables are control variables
(partial control). For systems evolving over a time domain (1D) the problems
of implementability by partial (regular) interconnection are well understood. In this
chapter, we study why similar results are not valid in themultidimensional (nD) case.
Finally, we study two important classes of controllers, namely, canonical controllers
and regular controllers
Rethinking place-making: aligning placeness factors with perceived urban design qualities (PUDQs) to improve the built environment in historical district
Understanding the concept of place is critically important for urban design and place-making practice, and this research attempted to investigate the pathways by which perceived urban design qualities (PUDQs) influence placeness factors in the Chinese context. Twelve hypotheses were developed and combined in a structural equation model for validation. The Tanhualin historical district in Wuhan, China was selected for the analysis. As a result, place attachment was verified as a critical bridge factor that mediated the influence of PUDQs on place satisfaction. Among the five selected PUDQs, walkability and space quality were revealed as the most influential factors associated with place attachment and place satisfaction. Accessibility was actually indirectly beneficial to place-making via the mediation of walkability. Corresponding implications and strategies were discussed to maintain the sense of place for historic districts
Algorithms for polynomial spectral factorization and bounded-real balanced state space representations
<p>We illustrate an algorithm that starting from the image representation of a strictly bounded-real system computes a minimal balanced state variable, from which a minimal balanced state realization is readily obtained. The algorithm stems from an iterative procedure to compute a storage function, based on a technique to solve a generalization of the Nevanlinna interpolation problem.</p>
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