Amélioration de la précision de systèmes d'extraction de relations en utilisant un filtre générique basé sur l'apprentissage statistique

RÉSUMÉ L’extraction de relations contribue à l’amélioration de la recherche sémantique, recherche basée sur la compréhension du sens des termes de recherche. Puisque la recherche d’information est principalement axée sur des mots-clés, l’extraction de relations offre un éventail de possibilités en identifiant les liens entre les entités. L’extraction de relations permet entre autres de transformer de l’information non structurée en information structurée. Les bases de connaissances,telles que Google Knowledge Graph et DBpedia, permettent un accès plus précis et plus direct à l’information. Le slot filling, qui consiste à peupler une base de connaissances à partir de textes, a été une tâche très active depuis quelques années faisant l’objet de plusieurs campagnes évaluant la capacité d’extraire automatiquement des relations prédéfinies d’un corpus de documents. Malgré quelques progrès, les résultats de ces compétitions demeurent modestes. Nous nous concentrons sur la tâche de slot filling dans le cadre de la campagne d’évaluation TAC KBP 2013. Cette tâche vise l’extraction de 41 relations prédéfinies basées sur les infobox de Wikipédia (par exemple: title, date of birth, countries of residence, etc.)liées à des entités nommées spécifiques (personnes et organisations). Une entité nommée (l’entité requête) et une relation sont soumises à un système (extracteur de relations) qui doit automatiquement trouver, parmi un corpus de plus de deux millions de documents, toute entité liée à l’entité requête par la relation donnée. Le système doit également retourner un segment textuel justifiant cette relation. Ce mémoire présente un filtre basé sur l’apprentissage statistique dont l’objectif principal est d’améliorer la précision d’extracteurs de relations tout en minimisant l’impact sur le rappel. Notre approche consiste à filtrer la sortie des extracteurs de relations en utilisant un classifieur. Notre filtre est annexé à la sortie de l’extracteur de relations, pouvant ainsi être facilement testé sur n’importe quel système. Notre classifieur est basé sur un large éventail de caractéristiques (features), incluant des caractéristiques statistiques, lexicales, morphosyntaxiques, syntaxiques et sémantiques extraites en majorité des phrases justificatives soumises par les systèmes. Nous proposons également une méthode efficace permettant d’extraire les patrons les plus fréquents (ex.: catégories orphosyntaxiques, dépendances syntaxiques) afin d’en dériver des caractéristiques booléennes utiles pour notre tâche de filtrage. Les caractéristiques utilisées pour l’entraînement des classifieurs sont soit génériques. Ainsi, notre méthode peut être utilisée pour la classification de toute relation prédéfinie. Nous avons testé le filtre sur 14 systèmes ayant participé à la tâche de slot filling. Le filtre permet d’améliorer la précision pour chacun de ces systèmes. Nos résultats démontrent également que le filtre permet d’améliorer la précision du meilleur système de plus de 20% (points de pourcentage) et d’améliorer le F-score pour 20 relations.----------ABSTRACT Relation extraction is becoming a very important challenge for enhanced semantic search. In fact, while traditional information retrieval is mainly focused on keywords, relation extraction opens a whole range of possibilities by identifying the links between concepts and entities. Unstructured data can be transformed into structured data by using effective relation extraction to populate a knowledge base (ex: Google Knowlegde Graph and DBpedia). Slot filling, which mainly consists in the population of a knowledge base, has been a very active task in recent years and has been subject to several evaluation campaigns that assess the ability of automatically extracting previously known relations from corpora. Despite some progress, the results of these competitions remain limited. In this thesis, we focus on the English slot filling track within TAC KBP 2013 evaluation campaign. This track targets the extraction of 41 pre-identified Wikipedia infobox relations (e.g. title, date of birth, countries of residence, etc.) related to specific named entities (persons and organizations). A named entity and a relation are submitted to a system (relation extractor), which must automatically find, within a corpus containing over 2 million documents, every other entity that is linked to the query entity with this particular relation, and must return a textual segment that justifies this result. This thesis presents a machine learning filter whose main objective is to enhance the precision of relation extractors while minimizing the impact on recall. Our approach consists in the filtering of relation extractors’ output using a binary classifier. Our filter is appended to the end of the relation extractor’s pipeline, thus allowing the filter to be tested and operated on any system. Another objective of this research is the identification of the most important features for the filtering step. Our classifier is based on a wide array of features including statistical, lexical, morphosyntactic, syntactic and semantic features. We also present a method for extracting the most frequent patterns (ex: part-of-speech, syntactic dependencies) between the query and the answer within the justification sentence from which we create boolean features indicating the presence of such patterns. The features used for training our classifiers are mostly generic and could be utilized to classify any pre-defined relation. We experimented the classifier on 14 systems participating in the English slot filling track of TAC KBP 2013 campaign. The filter allowed an increase in precision for every tested system. Our results also show that the classifier is able to improve the precision of the best system by more than 20% (in percentage points) and improve the F1-score for 20 relations

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| &lt; 0.03 at 95% confidence level. [Figure not available: see fulltext.