107 research outputs found
Efficient Online Timed Pattern Matching by Automata-Based Skipping
The timed pattern matching problem is an actively studied topic because of
its relevance in monitoring of real-time systems. There one is given a log
and a specification (given by a timed word and a timed automaton
in this paper), and one wishes to return the set of intervals for which the log
, when restricted to the interval, satisfies the specification
. In our previous work we presented an efficient timed pattern
matching algorithm: it adopts a skipping mechanism inspired by the classic
Boyer--Moore (BM) string matching algorithm. In this work we tackle the problem
of online timed pattern matching, towards embedded applications where it is
vital to process a vast amount of incoming data in a timely manner.
Specifically, we start with the Franek-Jennings-Smyth (FJS) string matching
algorithm---a recent variant of the BM algorithm---and extend it to timed
pattern matching. Our experiments indicate the efficiency of our FJS-type
algorithm in online and offline timed pattern matching
Lazy Abstraction-Based Controller Synthesis
We present lazy abstraction-based controller synthesis (ABCS) for
continuous-time nonlinear dynamical systems against reach-avoid and safety
specifications. State-of-the-art multi-layered ABCS pre-computes multiple
finite-state abstractions of varying granularity and applies reactive synthesis
to the coarsest abstraction whenever feasible, but adaptively considers finer
abstractions when necessary. Lazy ABCS improves this technique by constructing
abstractions on demand. Our insight is that the abstract transition relation
only needs to be locally computed for a small set of frontier states at the
precision currently required by the synthesis algorithm. We show that lazy ABCS
can significantly outperform previous multi-layered ABCS algorithms: on
standard benchmarks, lazy ABCS is more than 4 times faster
Rodents of Senegal and their role as intermediate hosts of Hydatigera spp. (Cestoda: Taeniidae)
Hydatigera (Cestoda: Taeniidae) is a recently resurrected genus including species seldom investigated in sub-Saharan Africa. We surveyed wild small mammal populations in the areas of Richard Toll and Lake Guiers, Senegal, with the objective to evaluate their potential role as intermediate hosts of larval taeniid stages (i.e. metacestodes). Based on genetic sequences of a segment of the mitochondrial DNA gene cytochrome c oxidase subunit 1 (COI), we identified Hydatigera parva metacestodes in 19 out of 172 (11.0%) Hubert's multimammate mice (Mastomys huberti) and one out of six (16.7%) gerbils (Taterillus sp.) and Hydatigera taeniaeformis sensu stricto metacestodes in one out of 215 (0.5%) Nile rats (Arvicanthis niloticus). This study reports epidemiological and molecular information on H. parva and H. taeniaeformis in West African rodents, further supporting the phylogeographic hypothesis on the African origin of H. parva. Our findings may indicate significant trophic interactions contributing to the local transmission of Hydatigera spp. and other parasites with similar life-cycle mechanisms. We therefore propose that further field investigations of rodent population dynamics and rodent-borne infectious organisms are necessary to improve our understanding of hostâparasite associations driving the transmission risks of rodent parasites in West Africa
Comparison of three fat suppression sequences for the detection of vertebral detection. Turbo STIR, phase contrast gradient-echo, and MISTEC-Chopper after gadolinium injection
OBJECTIVES: Assess three fat suppression sequences used to search for spinal metastases: TurboSTIR, phase contrast gradient-echo, and MISTEC-Chopper after gadolinium injection.
MATERIAL AND METHODS: A prospective study was conducted in 10 patients with primary neoplasia. MIR sequences acquired (1 Tesla) were TurboSTIR, T1 spin-echo with and without gadolinium injection, phase contrast gradient-echo and M-Chop after gadolinium injection. Signal intensity in normal bone marrow, metastatic tissue, and subcutaneous fat as well as background noise was measured. Signal-to-noise (S/N) ratio was determined. Lesion borders, artefacts, and extent of detected lesions were determined quantitatively. Bone marrow signal intensity was also recorded.
RESULTS: S/N ratio was best with gradient-echo which identified well the borders of lesions within the hemopoietic marrow. For lesions located in high-fat marrow (as in post-radiation marrow), the high intensity signal of the lesion confounded with the fat signal. TurboSTIR gave effective fat signal suppression and was particularly useful for yellow marrow, less so for red marrow. This technique confounded cell proliferation with perilesional edema (enlarging lesion extention). In one case, this sequence did not detect a small lesion visible with the two other sequences. This sequence was sensitive to artefacts (especially vascular artefacts) which can produce false nodular images. M-Chop gave good suppression of vertebral fat tissue (better for yellow marrow) but subjective detection of lesions was more difficult.
CONCLUSION: The phase contrast gradient-echo sequence after gadlinium injection appeared to be the best sequence excepting cases of post-trauma (radiotherapy or chemotherapy) fat transformation of the marrow where the TurboSTIR sequence could be preferred
Reversible brain edema associated to flow diverter stent procedures: a retrospective single-center study to evaluate frequency, clinical evolution, and possible mechanism
Background
Hemorrhage and ischemia after flow diverter stent (FDS) procedures for intracranial aneurysms are the most common complications and have been extensively described. Temporary brain edema (TBE) is an unknown complication that could be associated with particular FDS procedures.
Objective
To estimate the frequency, clinical presentation, imaging findings, and possible mechanisms associating TBE with FDS.
Methods
Unruptured aneurysms treated with FDS implantation performed in our service from June 2015 to March 2018 were reviewed. Medical antecedents, endovascular procedure, clinical assessments before and after treatment, aneurysm characteristics, and image records were collected. Artery diameters of patients in whom TEB developed were also calculated to investigate any correlation between TBE and anatomic descriptors.
Results
A total of 179 FDS procedures in 176 patients were reviewed. Six patients (3.4%) presented with symptomatic TBE, and all TBE patients had undergone FDS implantation from the middle cerebral artery (MCA) to the internal carotid artery (ICA). A Pearson product-moment correlation coefficient (PPCC) found smaller MCA diameters and MCA/ICA ratios in these 6 patients (respectively PPCC = â0.619, P < 0.04; PPCC = â0.647, P < 0.03). Hemorrhagic and ischemic complications were less frequent than TBE (2.3% and 1.1% vs. 3.4%).
Conclusions
TBE was more frequent than ischemic or hemorrhagic complications after FDS in this study. TBE seemed to be associated with a particular FDS positioning in small arteries, inducing flow changes and disruption of the bloodâbrain barrier
In vitro androgenesis response of French durum wheat
L’analyse de l’aptitude à l’androgenèse in vitro d’une collection de 100 génotypes de blé dur de France a montré que 50 plantes chlorophylliennes ont pu être régénérées à partir de 17 génotypes dont 4 lignées fixées (Mondur, Primadur, Eurodur, Megadur). 1,16 plantes chlorophylliennes pour 100 anthères mises en culture est le pourcentage le plus intéressant obtenu chez la lignée Mondur. L’effet génotypique est très significatif pour tous les paramètres analysés sauf pour le pourcentage de régénérations chlorophylliennes, car ce dernier reste assez faible et, par conséquent, peu discriminatoire. Le nombre de régénérations racinaires obtenu est un parametre qui a été inclus dans cette analyse, étant donné son niveau élevé
SPaCIFY: a Formal Model-Driven Engineering for Spacecraft On-Board Software
International audienceThe aim of this article is to present a model- driven approach proposed by the SPaCIFY project for spacecraft on-board software development. This ap- proach is based on a formal globally asynchronous lo- cally synchronous language called Synoptic, and on a set of transformations allowing code generation and model verification
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