Multi-referenced correction of the voice timbre distortions on telephone network

In a telephone link, the voice timbre is impaired by spectral distortions generated by the analog parts of the link. We first evaluate from a perceptual point of view an equalization method consisting in matching the long term spectrum of the processed signal to a reference spectrum. This evaluation shows a satisfying restoration of the timbre for most speakers. For some speakers however, a noticeable spectral distortion remains. That is why we propose a multi-referenced equalizer, based on a classification of speakers and using a different reference spectrum for each class. This leads to a decrease of the spectral distortion and, as a consequence, to a significant improvement of the timbre correction

How significant are differences obtained by neglecting correlations when testing for deformation: A real case study using bootstrapping with terrestrial laser scanner observations approximated by b-spline surfaces

B-spline surfaces possess attractive properties such as a high degree of continuity or the local support of their basis functions. One of the major applications of B-spline surfaces in engineering geodesy is the least-square (LS) fitting of surfaces from, e.g., 3D point clouds obtained from terrestrial laser scanners (TLS). Such mathematical approximations allow one to test rigorously with a given significance level the deformation magnitude between point clouds taken at different epochs. Indeed, statistical tests cannot be applied when point clouds are processed in commonly used software such as CloudCompare, which restrict the analysis of deformation to simple deformation maps based on distance computation. For a trustworthy test decision and a resulting risk management, the stochastic model of the underlying observations needs, however, to be optimally specified. Since B-spline surface approximations necessitate Cartesian coordinates of the TLS observations, the diagonal variance covariance matrix (VCM) of the raw TLS measurements has to be transformed by means of the error propagation law. Unfortunately, this procedure induces mathematical correlations, which can strongly affect the chosen test statistics to analyse deformation, if neglected. This may lead potentially to rejecting wrongly the null hypothesis of no-deformation, with risky and expensive consequences. In this contribution, we propose to investigate the impact of mathematical correlations on test statistics, using real TLS observations from a bridge under load. As besides TLS, a highly precise laser tracker (LT) was used, the significance of the difference of the test statistics when the stochastic model is misspecified can be assessed. However, the underlying test distribution is hardly tractable so that only an adapted bootstrapping allows the computation of trustworthy p-values. Consecutively, the extent to which heteroscedasticity and mathematical correlations can be neglected or simplified without impacting the test decision is shown in a rigorous way, paving the way for a simplification based on the intensity model

Contrôle de l'audibilité du bruit de quantification induit par la pré-distorsion d'un signal de parole

La conjugaison de la prédistorsion et de la quantification d'un signal de parole peut conduire, après ré-équilibrage spectral du signal, à une dégradation du rapport signal à bruit en réception. Nous proposons donc, dans ce contexte, deux méthodes de reformage spectral du bruit de quantification visant à masquer celui-ci, l'une fondée sur la réinjection, à l'entrée du quantificateur, de l'erreur de quantification filtrée, l'autre consistant à rechercher la séquence quantifiée maximisant un critère probabiliste de masquage. Les résultats objectifs montrent une forte capacité de masquage, tandis que l'évaluation subjective témoigne de la gêne perceptive occasionnée par le bruit résiduel sporadiquement non masqué

Measuring Sea Level with GPS-Equipped Buoys: A Multi-Instruments Experiment at Aix Island

Measuring sea-level in a global reference frame with sub-centimeter accuracy is a relevant challenge in the context of current global warming and associated sea-level rise. Global Navigation Satellite Systems (GNSS) can provide sea-level measurements directly referenced in an absolute geocentric frame. We present here the results of a multi-instruments experiment with three buoys equipped with Global Positioning System (GPS), a radar tide gauge and a tide pole. This experiment was carried out at Aix Island (West coast of France) on the 27-28 March 2012. The GPS buoys were evaluated against conventional tide gauge measurements through a Van de Casteele test. The Root Mean Square Error (RMSE) computed from the difference between the GPS-buoys and radar tide gauge data ranges from 1 cm to 2.2 cm, which is suitable for tidal applications and offers interesting perspectives for future sea-level variations studies.La medición del nivel del mar en un marco de referencias globales con una precisión subcentimétrica es un desafío importante en el contexto del calentamiento mundial actual y del aumento del nivel del mar asociado al mismo. Los Sistemas Mundiales de Navegación por Satélite (GNSS) pueden proporcionar medidas del nivel del mar directamente referenciadas en una estructura geocéntrica absoluta. Presentamos aquí los resultados de un experimento multi-instrumentos con tres boyas equipadas de un Sistema de Posiciona-miento Global (GPS), un mareógrafo con sistema de radar y una escala de mareas. Este experimento fue llevado a cabo en la Isla de Aix (Costa Occidental de Francia), los días 27 y 28 de Marzo del 2012. Las boyas GPS fueron evaluadas comparándolas con las medidas de los mareógrafos convencionales mediante un test Van de Casteele. El Error Cuadrático Medio (RMSE) calculado a partir de la diferencia entre los datos de las boyas GPS y los datos de mareógrafo, oscila de 1 a 2,2 cm, lo que es apropiado para las aplicaciones de mareas y ofrece perspectivas interesantes para futuros estudios de variaciones del nivel del mar.La mesure du niveau de la mer dans un référentiel mondial avec une précision sub-centimétrique est un défi pertinent dans le contexte actuel du réchauffement climatique et de l’élévation du niveau des mers qui en résulte. Les systèmes mondiaux de navigation par satellite (GNSS) peuvent fournir des mesures du niveau de la mer directement rapportées à un référentiel géocentrique absolu. Nous présentons ici les résultats d’une expérience multi-instruments avec trois bouées équipées d’un système de positionnement par satellite (GPS), un marégraphe à radar et une échelle de marée. Cette expérience a été effectuée à l’île d’Aix (côte ouest de la France) les 27 et 28 mars 2012. Les bouées GPS ont été éva-luées par rapport aux mesures du marégraphe conventionnel au moyen d’un test de Van de Casteele. L’erreur quadratique moyenne (RMSE) calculée à partir de la différence entre les données des bouées GPS et celles du marégraphe radar est comprise entre 1 cm et 2,2 cm, ce qui convient pour les applications marégraphique et offre d’intéressantes pers-pectives pour les futures études des variations du niveau de la mer

The mitochondrial protease HtrA2 restricts the NLRP3 and AIM2 inflammasomes.

Activation of the inflammasome pathway is crucial for effective intracellular host defense. The mitochondrial network plays an important role in inflammasome regulation but the mechanisms linking mitochondrial homeostasis to attenuation of inflammasome activation are not fully understood. Here, we report that the Parkinson\u27s disease-associated mitochondrial serine protease HtrA2 restricts the activation of ASC-dependent NLRP3 and AIM2 inflammasomes, in a protease activity-dependent manner. Consistently, disruption of the protease activity of HtrA2 results in exacerbated NLRP3 and AIM2 inflammasome responses in macrophages ex vivo and systemically in vivo. Mechanistically, we show that the HtrA2 protease activity regulates autophagy and controls the magnitude and duration of inflammasome signaling by preventing prolonged accumulation of the inflammasome adaptor ASC. Our findings identify HtrA2 as a non-redundant mitochondrial quality control effector that keeps NLRP3 and AIM2 inflammasomes in check

Memory Monitoring in a Multi-tenant OSGi Execution Environment

International audienceSmart Home market players aim to deploy component-based and service-oriented applications from untrusted third party providers on a single OSGi execution environment. This creates the risk of resource abuse by buggy and malicious applications, which raises the need for resource monitoring mechanisms. Existing resource monitoring solutions either are too intrusive or fail to identify the relevant resource consumer in numerous multi-tenant situations. This paper proposes a system to monitor the memory consumed by each tenant, while allowing them to continue communicating di-rectly to render services. We propose a solution based on a list of configurable resource accounting rules between tenants, which is far less intrusive than existing OSGi monitoring sys-tems. We modified an experimental Java Virtual Machine in order to provide the memory monitoring features for the multi-tenant OSGi environment. Our evaluation of the mem-ory monitoring mechanism on the DaCapo benchmarks shows an overhead below 46%

Incinerator - Eliminating stale references in dynamic OSGi applications

International audienceJava class loaders are commonly used in application servers to load, unload and update a set of classes as a unit. However, unloading or updating a class loader can introduce stale references to the objects of the outdated class loader. A stale reference leads to a memory leak and, for an update, to an inconsistency between the outdated classes and their replacements. To detect and eliminate stale references, we propose Incinerator, a Java virtual machine extension that introduces the notion of an outdated class loader. Incinerator detects stale references and sets them to null during a garbage collection cycle. We evaluate Incinerator in the context of the OSGi framework and show that Incinerator correctly detects and eliminates stale references, including a bug in Knopflerfish. We also evaluate the performance of Incinerator with the DaCapo benchmark on VMKit and show that Incinerator has an overhead of at most 3.3

Preventing Memory and Information LeakageIncinerator – Eliminating Stale References in Dynamic OSGi Applications

International audienceJava class loaders are commonly used in applicationservers to load, unload and update a set of classes as a unit.However, unloading or updating a class loader can introducestale references to the objects of the outdated class loader. Astale reference leads to a memory leak and, for an update,to an inconsistency between the outdated classes and theirreplacements. To detect and eliminate stale references, we proposeIncinerator, a Java virtual machine extension that introducesthe notion of an outdated class loader. Incinerator detects stalereferences and sets them to null during a garbage collection cycle.We evaluate Incinerator in the context of the OSGi frameworkand show that Incinerator correctly detects and eliminates stalereferences, including a bug in Knopflerfish. We also evaluatethe performance of Incinerator with the DaCapo benchmark onVMKit and show that Incinerator has an overhead of at most3.3%

Les contraintes de financement et compétitivité des PME au Cameroun

SMEs represent more than 95% of Cameroon's economic fabric and contribute 61% to job creation. However, access to finance is one of the major obstacles to their development. The objective of this article is to measure the influence of financing constraints on the competitiveness of Small and Medium-sized Enterprises (SMEs) in the western region of Cameroon. Attain that objective means to identify the financing constraints faced by SMEs in Cameroon and then to explain the nature of the relationship between these constraints and the competitiveness of SMEs. The sample of this study consists of 61 SMEs located in the West Cameroon region. From the SPSS 20 software, a multinomial regression was performed to measure the influence of each constraint on the competitiveness level of SMEs. The analysis shows that: interest rates, cash flows, managerial level and self-financing are indicators of financing constraints that significantly influence the level of competitiveness of SMEs in the region of West Cameroon. This study recommends to those SMEs to exploit better their human capital to conduct research and development works, in order to increase their competitivity.     JEL classification: M13, M21, G32 Paper Type: Empirical ResearchLes PME représentent plus de 95% du tissu économique camerounais et contribuent à hauteur de 61%à la création d’emplois. Cependant, l’accès au financement est l’un des obstacles majeurs pour leur développement. L’objectif de cet article est de mesurer l’influence des contraintes de financement sur la compétitivité des Petites et Moyennes Entreprises (PME) dans la région de l’Ouest Cameroun. Pour le réaliser, il est question d’identifier les contraintes de financement auxquelles font face les PME au Cameroun puis donner la nature de la relation entre ces contraintes et la compétitivité des PME. L’échantillon de cette étude est constitué de 61 PME localisées dans la région de l’Ouest-Cameroun. À partir du logiciel SPSS 20, une régression multinomiale a été effectuée pour mesurer l’influence de chacune des contraintes sur le niveau de compétitivité des PME. Il ressort de l’analyse que: le taux d’intérêt, les cash flows, le niveau d’instruction du dirigeant et l’autofinancement sont des indicateurs des contraintes de financement qui influencent significativement le niveau de compétitivité des PME dans la région de l’Ouest Cameroun. Cette étude recommande à ces PME de mieux exploiter leur capital humain pour mener des travaux de recherche et de développement en vue d’accroitre leur compétitivité.     Classification JEL: M13, M21, G32 Type de Papier : Recherche Empiriqu