Perturbed nonlinear elliptic Neumann problem involving anisotropic Sobolev spaces with variable exponents

In this paper we study the existence of infinitely many weak solutions of the following perturbed Kirchhoff-type non-homogeneous Neumann problem by applying technical approach based on critical points theorem due to B. Ricceri in a reflexive anisotropic Sobolev spaces. We use some suitable assumptions on the right had side but without using log-Ho ̈lder continu- ous condition

Comparison of the Average Kappa Coefficients of Two Binary Diagnostic Tests with Missing Data

The average kappa coefficient of a binary diagnostic test is a parameter that measures the average beyond‐chance agreement between the diagnostic test and the gold standard. This parameter depends on the accuracy of the diagnostic test and also on the disease prevalence. This article studies the comparison of the average kappa coefficients of two binary diagnostic tests when the gold standard is not applied to all individuals in a random sample. In this situation, known as partial disease verification, the disease status of some individuals is a missing piece of data. Assuming that the missing data mechanism is missing at random, the comparison of the average kappa coefficients is solved by applying two computational methods: the EM algorithm and the SEM algorithm. With the EM algorithm the parameters are estimated and with the SEM algorithm their variances‐covariances are estimated. Simulation experiments have been carried out to study the sizes and powers of the hypothesis tests studied, obtaining that the proposed method has good asymptotic behavior. A function has been written in R to solve the proposed problem, and the results obtained have been applied to the diagnosis of Alzheimerʹs disease

Confidence Intervals and Sample Size to Compare the Predictive Values of Two Diagnostic Tests

A binary diagnostic test is a medical test that is applied to an individual in order to determine the presence or the absence of a certain disease and whose result can be positive or negative. A positive result indicates the presence of the disease, and a negative result indicates the absence. Positive and negative predictive values represent the accuracy of a binary diagnostic test when it is applied to a cohort of individuals, and they are measures of the clinical accuracy of the binary diagnostic test. In this manuscript, we study the comparison of the positive (negative) predictive values of two binary diagnostic tests subject to a paired design through confidence intervals. We have studied confidence intervals for the difference and for the ratio of the two positive (negative) predictive values. Simulation experiments have been carried out to study the asymptotic behavior of the confidence intervals, giving some general rules for application. We also study a method to calculate the sample size to compare the parameters using confidence intervals. We have written a program in R to solve the problems studied in this manuscript. The results have been applied to the diagnosis of colorectal cancer

Global Hypothesis Test to Compare the Predictive Values of Diagnostic Tests Subject to a Case-Control Design

Use of a case-control design to compare the accuracy of two binary diagnostic tests is frequent in clinical practice. This design consists of applying the two diagnostic tests to all of the individuals in a sample of those who have the disease and in another sample of those who do not have the disease. This manuscript studies the comparison of the predictive values of two diagnostic tests subject to a case-control design. A global hypothesis test, based on the chi-square distribution, is proposed to compare the predictive values simultaneously, as well as other alternative methods. The hypothesis tests studied require knowing the prevalence of the disease. Simulation experiments were carried out to study the type I errors and the powers of the hypothesis tests proposed, as well as to study the effect of a misspecification of the prevalence on the asymptotic behavior of the hypothesis tests and on the estimators of the predictive values. The proposed global hypothesis test was extended to the situation in which there are more than two diagnostic tests. The results have been applied to the diagnosis of coronary disease.Spanish Ministry of Economy, Grant Number MTM2016- 76938-PUniversity of Nouakchott Alaasriy

Conception d’entrepôt : sélection des équipements de manutention et d'entreposage

RÉSUMÉ : L’entreposage est une activité nécessaire tout au long du cycle de vie d’un produit. Il est entreposé plusieurs fois dans la chaîne logistique sous forme de matières premières. Il est ensuite entreposé durant le processus de fabrication sous différentes formes (pièce, sous-ensemble, produit fini). Il est finalement entreposé en tant que produit fini chez les intervenants de distribution (grossistes, détaillants, etc.) avant d’être livré chez le consommateur. Le produit séjourne durant une bonne partie de sa vie dans les entrepôts sous toutes ses formes. Les coûts logistiques pèsent sur les entreprises. Ils peuvent être réduits en améliorant par exemple le processus de sélection des équipements logistiques. Il n'est pas toujours nécessaire de disposer d'équipements de manutention et d'entreposage coûteux et hautement automatisés. Selon la littérature du domaine, les concepteurs d’entrepôt et d’usine ont besoin d'outils d'aide à la décision pour choisir l'équipement convenable. L'équipement convenable désigne l'équipement le plus approprié à une opération spécifique de manutention ou d’entreposage de charges. Il possède les caractéristiques techniques requises et respecte les contraintes d'exploitation et d'environnement tout en étant rentable. Une revue de littérature regroupant 74 articles publiés entre 1985 et 2017 et traitant la sélection des équipements de manutention et d’entreposage est réalisée. Elle porte sur cinq différents aspects : buts ou problèmes abordés dans la sélection des équipements de manutention et d’entreposage; données d’entrée; méthodes de sélection; applications des solutions proposées; et validation des propositions. Elle a permis de mettre en évidence ce qui est accompli dans ce domaine jusqu’à aujourd’hui et élaborer des recommandations de recherche. À partir de ces recommandations, différentes contributions sont faites dans cette thèse. Une large collecte de données sur les systèmes d’entreposage destinés aux charges palettisées a été faite pour réaliser leurs fiches techniques. Un système d’entreposage est un équipement d’entreposage couplé à un équipement de manutention. Une validation de ces fiches techniques par l’entreprise Équipement BONI a été obtenue. Une méthodologie de sélection des systèmes d’entreposage destinés aux charges palettisées est proposée. Une extraction automatique de règles de sélection des systèmes desdits systèmes d’entreposage destinés aux charges palettisées est réalisée. Une méthodologie de sélection des équipements d’entreposage destinés aux petites charges est aussi proposée. Finalement, une évaluation du processus de sélection des équipements de manutention et d’entreposage dans un contexte 4.0 est réalisée. Différentes techniques et méthodes ont été adaptées pour réaliser ces contributions. Le raisonnement en logique floue est adopté afin de contourner le problème d’incertitude et d’imprécision des données. Les techniques et méthodes d’intelligence artificielle sont exploitées telles que le système basé sur la connaissance de la famille des systèmes experts et l’algorithme de classification de type apprentissage machine C4.5. Les méthodes d’aide à la décision multicritère à savoir FTOPSIS et AHP sont aussi adaptées aux différents problèmes. Les propositions de cette thèse sont pour la plupart des premiers essais dans ce domaine. Les défauts de la charge palettisée sont tenus compte lors de la sélection des systèmes d’entreposage destinés aux charges palettisées aux côtés des autres critères pour la première fois dans la littérature. Les défauts de la charge palettisée sont : défauts de construction; défauts de forme; défauts d’occupation de la surface de la palette; autres types de défauts; défauts d’emballage des colis et état de la palette. L’application des techniques d’exploration de données (Data mining) au problème de sélection des systèmes d’entreposage destinés aux charges palettisées est aussi une première tentative. La contextualisation de la sélection des équipements de manutention et d’entreposage dans l’ère de la quatrième révolution industrielle indique l’aspect évolutif des problèmes logistiques. Les travaux de cette thèse pourront servir d’inspiration à d’autres efforts de recherche pour contribuer davantage à améliorer les outils d’aide à la décision destinés aux concepteurs d’entrepôt et d’usine. Une mise à jour continue des bases de données est nécessaire afin d’intégrer les avancements technologiques. Les méthodologies de sélection proposées pourraient être programmées en langage informatique afin d’automatiser les processus.----------ABSTRACT : Warehousing is a necessary activity throughout the life cycle of a product. The product is warehoused as a raw material at the supplier or at different locations during the supply chain. It is then warehoused during the production process in various forms (part, sub-assembly, finished product). It is finally warehoused as a finished product in different locations (wholesalers, retailers, etc.) before being delivered to the consumer. The product stays in warehouses during a considerable part of its life. Logistics costs represent a significant percentage of a manufactured product’s total cost. To reduce costs, savings in logistics equipment could be found. This is possible with an efficient equipment selection. Costly, highly automated material handling equipment or warehousing equipment is not always necessary. According to the literature of the field, warehouse or plant designers need decision aid tools to better select suitable equipment. Suitable equipment refers to the most appropriate equipment for a material handling or warehousing operation, and it possesses the required technical characteristics and respects the operation and environmental constraints while being cost effective. A literature review including a selection of 74 papers published between 1985 and 2017 and addressing the material handling equipment selection is realized. It covers five different aspects: aims or issues addressed in the selection of material handling and warehousing equipment; input data; methods for selecting; applications of proposed solutions; and validation of proposals. It enabled us to know what has been done up to now in this field and make further research suggestions. Based on these suggestions, different contributions are made in this thesis. A widespread collection of data on warehousing systems designed for palletized loads is made to elaborate their technical data sheets. A warehousing system is a warehousing equipment coupled with material handling equipment. These technical data sheets have been validated by Equipment BONI Inc. A methodology for the selection of warehousing systems designed for palletized loads is proposed. Rules for the selection of warehousing systems designed for palletized loads are automatically extracted. A methodology for the selection of warehousing equipment designed for small loads is proposed. Finally, an evaluation of the selection process of material handling and warehousing equipment in a 4.0 environment is realized

Usutu virus in Africa.

Usutu virus (USUV) was discovered in South Africa in 1959. Since then, it has been reported in several African countries including Senegal, Central African Republic, Nigeria, Uganda, Burkina Faso, Cote d'Ivoire, and Morocco. In 2001, USUV has been identified for the first time outside of Africa, namely in Europe, where it caused a significant mortality among blackbirds in Vienna, Austria. In 2009, the first two human cases of USUV infection in Europe have been reported in Italy, causing encephalitis in immunocompromised patients. The host range in Africa includes mainly Culex mosquitoes, birds, and also humans with one benign and one severe case. Given its role as a potential human pathogen and the similar appearance compared with other emerging arboviruses, it is essential to investigate the natural history and ecology of USUV in Africa. In this regard, we review the emergence of USUV in Africa, summarizing data about isolations, host range, and potential vectors, which should help to improve our understanding of the factors underlying the circulation of USUV in Europe and Africa

Enhancement of biogas production from sewage sludge by biofilm pretreatment method

Since the last two decades, different pre-treatment methods have been proposed to enhance the yield of biogas production from sewage sludge. In order to improve the biogas yield and to find an alternative and economically suitable pretreatment method, a biological pretreatment method using a biofilm was studied. The biofilm constituted of four strains of bacteria producing hydrolyzes was used as an immobilized biocatalyst for the pretreatment of the sludge. Based on the data obtained during this study, the optimum biofilm was formed within 2 days. The best amount of GAC that has given an optimum biofilm was 4g. An improvement of 16.9% on the SCOD/TCOD and 28.3% in the volatile solids (VS) was achieved after 12 hours of pretreatment at room temperature (30 ± 2⁰C). Comparing to the no pretreated sludge (control), 15% of an increase in the cumulative biogas production was observed after 14 days of digestion with 30% v/v of inoculum (anaerobic sludge) at 37⁰C and 25 days of HRT. It can be concluded that the developed pretreatment method can be used for the enhancement of the biogas production from sewage sludge at mesophilic temperature range