Generic and adaptable online configuration verification for complex networked systems

International audienceDynamic reconfiguration is viewed as a promising solution for today's complex networked systems. However, considering the critical missions actual systems support, systematic dynamic reconfiguration cannot be achieved unless the accuracy and the safety of reconfiguration activities are guaranteed. In this paper, we describe a model-based approach for runtime configuration verification. Our approach uses model-driven engineering techniques to implement a platform-independent online configuration verification framework that can operate as a lightweight extension for networked systems management solutions. The framework includes a flexible and adaptable runtime verification service built upon a high-level language dedicated to the rigorous specification of configuration models and constraints guarding structural correctness and service behavior conformance. Experimental results with a real-life messaging platform show viable overhead demonstrating the feasibility of our approach

L’institution de la littérature gabonaise : Partie I

Depuis bientôt trois (3) ans, le Docteur Heméry-Hervais SIMA-EYI enseignant et directeur en outre, du Centre d’études pour la littérature gabonaise(CELIG) anime à la faculté des lettres et des sciences humaines, notamment au sein du département des Littératures Africaines de l’Université Omar Bongo, un séminaire intitulé « Littérature et société au Gabon » . Ce séminaire vise à étudier, analyser la littérature gabonaise dans ses rapports apparents avec la société dans laquelle cette littérature est produite. Pour ce faire, le Docteur SIMA-EYI a demandé à ses étudiants de voir, dans l’optique d’un colloque sur la littérature gabonaise , quelle place les institutions littéraires(maisons d’éditions, universités, centres de recherche, ministères, etc.)accordent à la littérature produite dans notre pays . Ainsi, scindée en deux(2) groupes,l’un dirigé par Guy Wilfried IDIATHA et l’autre par Désiré Clitandre DZONTEU, la classe de licence des Littératures Africaines s’est donc penchée sur cet épineux problème. Notre équipe s’est intéressée au groupe bancaire BICIG et son concours littéraire et artistique ; au Théâtre national ; aux maisons d’éditions entre autres, La Maison Gabonaise du Livre, Ndzé, Hilaire Makaya et les éditions du silence ; l’Union des écrivains gabonais(UDEG), l’Ecole Normale supérieure(ENS) et l’organisation des Nations unies pour l’éducation , la science et la culture(UNESCO). Il est sans rappelé que ce travail ne fut pas une sinécure, plutôt parfois un parcours du combattant. -------------------------------------------------------------------------------------------- CRELAF (Cercle de Reflexion des Etudiants en Littératures Africaines), Département de Littératures Africaines, Université Omar Bongo, Gabo

Integrating an Online Configuration Checker with Existing Management Systems : Application to CIM/WBEM Environments

National audienceRuntime configuration validation is a critical requirement if we are to build reliable self-adaptive management systems. This paper presents a generic framework that includes a runtime configuration checker built upon a high-level language dedicated to the specification of configurations and validity constraints. In addition, we describe a methodology for using this framework and integrating the configuration checker with existing management systems. In particular, we show how we use the framework to enrich a CIM/WBEM management environment with automatic runtime configuration validation against a defined set of constraints guarding structural correctness and service behavior conformance. Our experiments with management models conforming to the CIM Virtual System profile show viable results demonstrating the feasibility of our approach

Runtime Configuration Validation for Self-configurable Systems

International audienceRuntime configuration validation is a critical requirement if we are to build reliable self-adaptive systems. This paper describes a model-based approach that supports runtime validation of candidate configurations. The approach is based on MeCSV, a metamodel we propose, that allows a technologyneutral specification of systems' configurations and validity constraints. A constraint-checker relying on this specification verifies dynamically candidate configurations before their deployment. Experimental results with a messaging platform show viable validation overhead demonstrating the feasibility of the approach

Evidence against Wolbachia symbiosis in Loa loa

BACKGROUND: The majority of filarial nematode species are host to Wolbachia bacterial endosymbionts, although a few including Acanthocheilonema viteae, Onchocerca flexuosa and Setaria equina have been shown to be free of infection. Comparisons of species with and without symbionts can provide important information on the role of Wolbachia symbiosis in the biology of the nematode hosts and the contribution of the bacteria to the development of disease. Previous studies by electron microscopy and PCR have failed to detect intracellular bacterial infection in Loa loa. Here we use molecular and immunohistological techniques to confirm this finding. METHODS: We have used a combination of PCR amplification of bacterial genes (16S ribosomal DNA [rDNA], ftsZ and Wolbachia surface protein [WSP]) on samples of L. loa adults, third-stage larvae (L3) and microfilariae (mf) and immunohistology on L. loa adults and mf derived from human volunteers to determine the presence or absence of Wolbachia endosymbionts. Samples used in the PCR analysis included 5 adult female worms, 4 adult male worms, 5 mf samples and 2 samples of L3. The quality and purity of nematode DNA was tested by PCR amplification of nematode 5S rDNA and with diagnostic primers from the target species and used to confirm the absence of contamination from Onchocerca sp., Mansonella perstans, M. streptocerca and Wuchereria bancrofti. Immunohistology was carried out by light and electron microscopy on L. loa adults and mf and sections were probed with rabbit antibodies raised to recombinant Brugia malayi Wolbachia WSP. Samples from nematodes known to be infected with Wolbachia (O. volvulus, O. ochengi, Litomosoides sigmodontis and B. malayi) were used as positive controls and A. viteae as a negative control. RESULTS: Single PCR analysis using primer sets for the bacterial genes 16S rDNA, ftsZ, and WSP were negative for all DNA samples from L. loa. Positive PCR reactions were obtained from DNA samples derived from species known to be infected with Wolbachia, which confirmed the suitability of the primers and PCR conditions. The quality and purity of nematode DNA samples was verified by PCR amplification of 5S rDNA and with nematode diagnostic primers. Additional analysis by 'long PCR' failed to produce any further evidence for Wolbachia symbiosis. Immunohistology of L. loa adults and mf confirmed the results of the PCR with no evidence for Wolbachia symbiosis. CONCLUSION: DNA analysis and immunohistology provided no evidence for Wolbachia symbiosis in L. loa

Age-related prevalence of antibody response against three different, defined Plasmodium falciparum antigens in children from the Haut-Ogooué province in Gabon

The kinetics of the humoral response to defined Plasmodium falciparum antigens was studied in 543 children, 1 month to 15 years old, living in an area endemic for malaria. The antigens used for enzymelinked immunosorbent assay were (i) the synthetic peptide (NANP)40 representing the immunodominant repeated region of the circumsporozoite protein, and (ii) the fusion peptide 31.1, representing the N-terminal portion of the 83 kDa polypeptide expressed at the surface of merozoites which is a processed product of the 190-200 kDa glycoprotein. In addition, glutaraldehyde-fixed infected red blood cells (RBC) were used to detect ring-infected erythrocyte surface antigen (RESA) and unfixed infected RBC to detect intra-erythrocytic asexual form (IEF) antigens by immunofluorescence. In the 1 to 2 months age group, 50%, 26% and 21% of the children had antibodies for IEF, (NANP)40 and 31.1 respectively, but none had anti-RESA antibodies. The proportions of positive subjects decreased until 3 to 6 months and then increased progressively for the 4 antigens, approaching, but not reaching, adult values by the age of 15 years. Antibodies against specific antigens were acquired concomitantly. Children born from (NANP)40-positive mothers showed enhanced anti-(NANP)40 IgG response

Neural TTS in French: Comparing Graphemic and Phonetic Inputs Using the SynPaFlex-Corpus and Tacotron2

The SynPaFlex-Corpus is a publicly available TTS-oriented dataset, which provides phonetic transcriptions automatically produced by the JTrans transcriber, with a Phoneme Error Rate (PER) of 6.1%. In this paper, we analyze two mono-speaker Tacotron2 models trained on graphemic and phonetic inputs, provided by the SynPaFlex-Corpus. Through three subjective listening tests, we compare their pronunciation accuracy, sound quality and naturalness. Our results show significantly better pronunciation accuracy and prosody naturalness for the phoneme-based model, but no significant difference in terms of perceived sound quality. They demonstrate that a PER of 6.1% is sufficient to enhance pronunciation control by using phonetic transcripts instead of graphemes with 83 hours of recorded French read speech. They suggest that the SynPaFlex-Corpus is suitable for pre-training a model in mono-speaker fine-tuning approaches.Comment: 6 pages, 3 figure

Synthesis of a C-Linked Methyl β-Disaccharide as a Building Block of Hyaluronic Acid Oligosaccharide Mimetics

Hyaluronic acid is a viscous high MW polysaccharide that is synthesized in the plasma membrane. It is found in the connective tissue space, in the synovial fluid of movable joints and in the vitreous humor of the eye. Its chemical structure is composed of a repeating disaccharide unit in which D-glucuronic acid is linked to the 3-position of N-acetyl-D-glucosamine. It appears to play an important role in the metastasis of cancer cells since cancer cell’s CD44 receptors adhere to it and migrate to host cells. Our goal was to synthesize small HA-oligosaccharides that would behave as CD44 metastasis receptor antagonists. However, HA is degraded in the liver, in the lymph nodes, as well as in local tissues by acid hydrolases. Several lines of evidences have established that replacing the glycosidic –O– linkages with –CH2– linkages provides resistance to enzymatic cleavage. Since synthesizing an all –CH2– linked oligosaccharide is an arduous task and virtually intractable, it was decided to design hydrolase-resistant HA mimics by substituting the interglycosidic oxygen atom with the CH2-group at strategical positions. In this dissertation is described the synthesis of a –CH2– linked disaccharide to a methyl β-analog related to HA that can serve as a building block for the synthesis of long-chain, hydrolase-resistant oligosaccharide mimics. The C-disaccharide was acquired from coupling a glycosyl tin derivative with an aldehyde stemming from methyl β-D-glucopyranoside

3D Cell Culture Droplet Spheroids: An Engineered Approach Towards Drug Toxicity Assessment

The development of biologically relevant and human-mimicking platforms underlines the appropriate study of novel technologies for human diseases. Previously, animal and 2D models have been used as standard model systems to understand the toxicity of different drugs. The lack of physiological relevance of these systems has given rise to more adequate models such as organoids, and spheroids. These "mini-organs" [1] are expected to have the same complexity as human organs [2]. They have been effectively used in a variety of tissue engineering subfields for cancer predictions and drug development [3]. However, the majority of these systems are built through manual pipetting and liquid handling [2] which leads to a lack of uniformity of the droplets. In this work, a droplet microfluidics approach is implemented to combat the heterogeneity of these non-engineered systems. We demonstrated the tunability of the size of the 3D droplets and the successful encapsulation of 3T3 cells inside the droplets. Due to its versatility, the developed platform can be used for various biomedical applications such as cancer drug toxicity assessment