Uncertainty in Automated Ontology Matching: Lessons Learned from an Empirical Experimentation

Data integration is considered a classic research field and a pressing need within the information science community. Ontologies play a critical role in such a process by providing well-consolidated support to link and semantically integrate datasets via interoperability. This paper approaches data integration from an application perspective, looking at techniques based on ontology matching. An ontology-based process may only be considered adequate by assuming manual matching of different sources of information. However, since the approach becomes unrealistic once the system scales up, automation of the matching process becomes a compelling need. Therefore, we have conducted experiments on actual data with the support of existing tools for automatic ontology matching from the scientific community. Even considering a relatively simple case study (i.e., the spatio-temporal alignment of global indicators), outcomes clearly show significant uncertainty resulting from errors and inaccuracies along the automated matching process. More concretely, this paper aims to test on real-world data a bottom-up knowledge-building approach, discuss the lessons learned from the experimental results of the case study, and draw conclusions about uncertainty and uncertainty management in an automated ontology matching process. While the most common evaluation metrics clearly demonstrate the unreliability of fully automated matching solutions, properly designed semi-supervised approaches seem to be mature for a more generalized application

Synthèse et utilisation de nouveaux matériaux hybrides pour la catalyse en ATRP supportée du méthacrylate de méthyle

The aim of this project is to develop hybrid nanoparticles bearing well definedpolymer arms as supported catalyst for the atom transfer radical polymerization of methylmethacrylate. This new generation of “semi heterogeneous" catalysts was prepared by twostrategies. The first consisted of immobilizing the polymer arms bearing the ligands enablingcoordination of copper bromide onto silica particles by covalent bonds. Hybrid nanoparticleswith low polymer grafting density were targeted to prevent the overlapping of chains on thesurface. Unfortunately, the polymerizations were not controlled probably due to a lack ofaccessibility of the initiator and propagating radicals to the copper complexes. To improve theaccessibility, a reversibly supported catalyst was developed via self-assembly using hydrogenbonding between chains α-functionalized by a proton donor-acceptor unit (DAD) and acomplementary unit (ADA) anchored on silica particles. These new hybrid materials wereefficient in the controlled radical polymerization of MMA, yielding polymers with controlledmolecular weights and dispersities narrower than those obtained for homogeneous ATRP.Moreover, after catalyst separation from the reaction medium by centrifugation, more than96% of the originally used copper was recovered.L’objectif était de développer et d’utiliser des nanoparticules hybrides de type«coeur-écorce» composées d’un coeur de silice dense entouré par des chaînes polymères fonctionnalisées par des ligands d’ATRP comme support catalytique pour la polymérisation du MMA par ATRP. Deux stratégies de synthèse de nanoparticules hybrides ont été élaborées. La première a consisté à immobiliser sur un support de silice, d’une manière covalente, des chaînes fonctionnelles synthétisées par NMP comportant des ligands capables de complexer le bromure de cuivre. Des nanoparticules de SiO2@polymère fonctionnel ayant de faibles densités de greffage en polymère ont été ciblées afin d’éviter leur recouvrement sur la surface. Cependant, les polymérisations n’étaient pas contrôlées probablement à cause d’un manque d’accessibilité de l’amorceur et des radicaux propageants aux complexes decuivre. Afin de rendre les catalyseurs supportés plus accessibles en solution, nous avons élaboré une seconde stratégie basée sur un système catalytique hybride réversible. Il consiste à immobiliser des chaînes α-fonctionnalisées par un motif donneur-accepteur de proton(DAD) via des liaisons hydrogène sur des particules de silice modifiées par un motif complémentaire (ADA). Des PMMA de masses molaires contrôlées ont été synthétisés avec des dispersités plus faibles que celles obtenues en ATRP homogène (en présence des chaînes libres). Après séparation du catalyseur du milieu réactionnel par centrifugation, nous avons montré qu’avec un excès du motif ADA, 96% du cuivre initialement introduit ont été récupérés

Les fondements de l'écriture selon Michel Foucault et Roland Barthes

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Sensibilité de la réaction de conversion de l'éthanol en n-butanol à la structure des hydroxyapatites : mode de fonctionnement

StructureHydroxyapatites (HAps) are basic materials which exhibit atypical catalytic properties, particularly a high selectivity in n-butanol from ethanol’s conversion. Versatility in terms of composition and morphology, easily tuned by synthesis, is accompanied by a high modularity of acid-base properties of the surface, which allowed us to establish structure-reactivity relationships in order to rationalize how the system works at a molecular level. Certainly stoichiometry, represented by the bulk Ca/P ratio, is a key parameter for the activity of these materials for this type of reaction, but it seems that the concentration of OH in the columns governs the conversion level, highlighting the role of these species as basic sites. Beyond this macroscopic aspect, an approach intended for the discrimination of the bulk and surface spectroscopic contributions of OH, PO43- and PO-H was implemented by IR and solid state NMR via H-D isotopic exchanges, thermal pretreatments and specific NMR sequences. The involvement of the present sites on the surface was investigated by adsorption of probe molecules. The CO2 adsorption revealed the low basicity of the surface generating hydrogenocarbonates and carbonates, respectively as a result of the interaction with the basic surface OH and oxygens of the phosphate groups. Only basic OH sites emerging from the columns are involved in the interaction with the acetylene, in association with Brönsted acids PO-H (protonated terminated phosphates). Calcium ions are inaccessible (CO adsorption and XPS data) and the increase of its relative accessibility via the modulation of the post-synthesis parameters does not promote the formation of n-butanol. Monitoring the reaction conversion of ethanol in operando mode supports the participation of the acid-base pair PO-H/OH in the catalytic process. The study of the influence of the morphology on the catalytic behavior of HAps led us to propose that beyond the enhancement of the reactivity on the (001) surfaces, the elongation of the particles is also beneficial to the catalytic process. The role of the protons mobility, activated by temperature, may unify all the experimental data that reflect a good sensitivity to the structure.Les hydroxyapatites (HAps) sont des matériaux basiques qui présentent des propriétés catalytiques atypiques, notamment une sélectivité importante en butanol à partir de l’éthanol. Leur versatilité en termes de composition et de morphologie, facilement contrôlée par la synthèse, s’accompagne d’une grande modularité des propriétés acido-basiques de la surface, ce qui nous a permis d’établir des relations structure-réactivité dans l’objectif de rationaliser son mode de fonctionnement au niveau moléculaire. Certes, la stœchiométrie qui traduit le rapport Ca/P est un paramètre clé pour l’activité de ces matériaux dans ce type de réaction mais il s’avère que c’est plus précisément la concentration massique des OH des colonnes qui gouverne le niveau de la réactivité, ce qui oriente vers l’implication de ces espèces en tant que sites basiques. Au delà de cet aspect macroscopique, une approche visant la discrimination des contributions des OH-, PO43- et PO-H de surface et de cœur a été menée par IR et RMN du solide via des échanges isotopiques H-D, des prétraitements thermiques et des séquences RMN spécifiques. L’implication dans les interactions acides ou basiques des sites présents en surface a été suivie par adsorption de molécules sonde. L’adsorption du CO2 a révélé le caractère basique faible de la surface des HAps en générant des hydrogénocarbonates et des carbonates, respectivement suite à l’implication des OH basiques de terminaison en surface et des oxygènes de groupements phosphates. Seuls les OH qui émergent des colonnes sont impliqués dans l’interaction avec l’acétylène, conjointement avec les acides de BrØnsted PO-H (phosphates de terminaisons protonés). Les ions calcium sont peu accessibles (adsorption de CO et données XPS) et l’augmentation de leur accessibilité relative via la modulation de paramètres post-synthèse ne favorise pas la formation du n-butanol. Le suivi de la réaction de conversion d’éthanol en mode operando appuie la participation de la paire acide-base PO-H/OH dans le processus catalytique. L’étude de l’influence de la morphologie sur le comportement catalytique des HAps nous a incités à proposer qu’au-delà d’une réactivité favorisée sur les faces (001), l’allongement des particules bénéficie aussi au processus catalytique. Plus largement, le rôle joué par la mobilité des protons qui est un processus activé en température, permettrait d’unifier l’ensemble des données expérimentales qui rendent compte d’une sensibilité à la structure

Pigmented Lesion on the Cheek: A Quiz

International audienceQui

Radial neck fracture in children: anatomic and functional results of Metaizeau technique

Fractures of the radial neck accounts for 1% of all childhood fractures and 5% to 10% of childhood traumatic lesions involving the elbow. Intramedullary percutaneous nail reduction (Metaizeau technique) is considered the most effective surgical technique. The purpose of this study was to identify the main clinical features of radial neck fracture in children and to evaluate the anatomical and functional results of the Metaizeau technique. In this retrospective study, we evaluated 22 patients under the age of 16 who were treated for radial neck fracture at the orthopedic and trauma surgery department of Sahloul University Hospital in Sousse over a period of 16 years from January 2001 to April 2017. Authors used Metaizeau classification. Functional results were evaluated by Mayo elbow performance score (MEPS) and the radiological evaluation was based on standard images with measurement of the residual rocker. The average age was 8.6 years (5-13 years). Seven fracture were grade III injuries and three grade IV. In the immediate postoperative period, radiological measurements showed a residual rocker less than 20° in 86.3% and more than 20° in 13.7% of cases. At an average follow-up of 13 months and a half, the MEPS score was excellent and good for 17 patients. Four types of complications were found: necrosis of the radial head in 1 case, pseudarthrosis in 1 case, periarticular calcification in 2 cases and stiff-ness of the elbow in 3 cases. Despite the small number of patients in our series, we believe that the elastic stable intramedullary pinning according to the Metaizeau technique is the treatment of choice for displaced radial neck fractures in children

An Alignment-Based Implementation of a Holistic Ontology Integration Method

Despite the intense research activity in the last two decades, ontology integration still presents a number of challenging issues. As ontologies are continuously growing in number, complexity and size and are adopted within open distributed systems such as the Semantic Web, integration becomes a central problem and has to be addressed in a context of increasing scale and heterogeneity. In this paper, we describe a holistic alignment-based method for customized ontology integration. The holistic approach proposes additional challenges as multiple ontologies are jointly integrated at once, in contrast to most common approaches that perform an incremental pairwise ontology integration. By applying consolidated techniques for ontology matching, we investigate the impact on the resulting ontology. The proposed method takes multiple ontologies as well as pairwise alignments and returns a refactored/non-refactored integrated ontology that faithfully preserves the original knowledge of the input ontologies and alignments. We have tested the method on large biomedical ontologies from the LargeBio OAEI track. Results show effectiveness, and overall, a decreased integration cost over multiple ontologies.•OIAR and AROM are two implementations of the proposed method.•OIAR creates a bridge ontology, and AROM creates a fully merged ontology.•The implementation includes the option of ontology refactoring

Amputation of Glans Penis: A Rare Circumcision Complication and Successful Management with Primary Anastomosis and Hyperbaric Oxygen Therapy

Penile amputation is an uncommon condition that requires immediate surgical replantation. Routine standardized procedures for dealing with this medical condition do not exist. We describe a case of complete guillotine-type glans penis amputation and review the relevant literature. We performed urethral end-to-end approximation and glanular anastomosis and then applied hyperbaric oxygen therapy postoperatively. We obtained very good cosmetic and functional results

Detection of JavaScript Injection Eavesdropping on WebRTC communications

WebRTC is a Google-developed project that allows users to communicate directly. It is an open-source tool supported by all major browsers. Since it does not require additional installation steps and provides ultra-low latency streaming, smart city and social network applications such as WhatsApp, Facebook Messenger, and Snapchat use it as the underlying technology on the client-side both on desktop browsers and mobile apps. While the open-source tool is deemed to be secure and despite years of research and security testing, there are still vulnerabilities in the real-time communication application programming interface (API). We show in this paper how eavesdropping can be enabled by exploiting weaknesses and loopholes found in official WebRTC specifications. We demonstrate through real-world implementation how an eavesdropper can intercept WebRTC video calls by installing a malicious code onto the WebRTC webserver. Furthermore, we identify and discuss several, easy to perform, ways to detect wiretapping. Our evaluation shows that several indicators within webrtc-internals API traces can be used to detect anomalous activities, without the need for network monitoring tools