Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
An approximation method which combines Tikhonov method with the proximal point algorithm, is presented. Conditions which guarantee the convergence to a particular element of the solution set, are provided. A particular attention is given to the convex and convex-concave optimization cases.
ISSN: 0233-1934

hal-00815513
https://hal.univ-antilles.fr/hal-00815513
DOI : 10.1080/02331939608844217

Éditeur(s) : HAL CCSD School of Communications and Informatics
Résumé : International audience
The hybrid proximal point algorithm introduced by Solodov and Svaiter allowing significant relaxation of the tolerance requirements imposed on the solution of proximal subproblems will be combined with the inertial method introduced by Alvarez and Attouch which incorporates second order information to achieve faster convergence. The weak convergence of the resulting method will be investigated for finding zeroes of a maximal monotone operator in a Hilbert space.
ISSN: 1443-5756

hal-00780745
https://hal.univ-antilles.fr/hal-00780745
https://hal.univ-antilles.fr/hal-00780745/document
https://hal.univ-antilles.fr/hal-00780745/file/170_03_www.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Abstract In this paper we prove the convergence of the approximate proximal method for DC functions proposed by Sun et al [6]. Our analysis also permits to treat the exact method. We then propose an interesting result in the case where the second component of the DC function is differentiable and provide some computational experiences which proved the efficiency of our method.
Journal of Computational Mathematics,

hal-00780885
https://hal.univ-antilles.fr/hal-00780885

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The aim of this paper is to investigate the asymptotic behavior of an inertial alternating algorithm based on the composition of resolvents of monotone operators. The proposed algorithm is a generalization of those proposed in Attouch et al. (2007) and Bauschke et al. (2005). As a special case, we also recover the classical alternating minimization algorithm (Acker, 1980), which itself is a natural extension of the alternating projection algorithm of von Neumann (1950) [4]. An application to equilibrium problems is also proposed.
ISSN: 0893-9659

hal-00776658
https://hal.univ-antilles.fr/hal-00776658
DOI : 10.1016/j.aml.2010.01.023

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: In Guadeloupe and Martinique, two French Overseas Departments, colorectal cancer (CRC) has become an essential public health issue. However, little is known about CRC characteristics and the p53 status in these populations, particularly in Guadeloupe, whereas certification of a cancer registry has been recently validated. METHODS: This was a descriptive retrospective study of 201 patients who, between 1995 and 2000, underwent surgery for CRC in the Guadeloupe Teaching Hospital (GlpeTH; 83 patients) and in the Martinique Teaching Hospital (MqueTH; 118 patients). The clinicopathological features and the p53 expression, evaluated with immunohistochemistry, were compared at the time of diagnosis. A relationship between these parameters and the p53 expression was also studied. Data were analysed, using the SPSS computer software version 17.0. RESULTS: No statistical difference was found between the two groups of patients regarding age (p = 0.60), percentage of young patients (<=50 years; p = 0.94)), sex (p = 0.47), histological type (p = 0.073) and tumour sites (p = 0.65), although the GlpeTH patients were diagnosed with more distal colon cancers (54.2%) than the Mque TH patients (47.4%). By contrast, a significant difference was found regarding the tumour grade (p < 0.0001), the pTNM stage (p = 0.045) and the pT stage (p < 0.0001). Regarding p53 expression, solely for the MqueTH patients, nuclear expression was associated with pTNM, the percentage of p53 negative tumours increasing with the progression of the pTNM stages (p = 0.029). CONCLUSIONS: For the first time, this study reveals discrepancies in clinicopathological features and in the p53 status between the two groups of patients. The GlpeTH patients were diagnosed with more moderated CRCs but with few CRCs at pTNM IV stage. By contrast, the MqueTH patients were diagnosed with more differentiated tumours, but with many more CRCs at pTNM IV stage. This paradox may be due to differences in tumour location (distal vs proximal), multiplicity of the genetic profiles of patients, or patients getting treatment elsewhere. Although our study is limited due to its small size, it emphasizes the originality of our results.
ISSN: 1472-6890

inserm-00971313
http://www.hal.inserm.fr/inserm-00971313
http://www.hal.inserm.fr/inserm-00971313/document
http://www.hal.inserm.fr/inserm-00971313/file/1472-6890-14-12.pdf
DOI : 10.1186/1472-6890-14-12

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Heterogeneous patterns of malaria transmission are thought to be driven by factors including host genetics, distance to mosquito breeding sites, housing construction, and socio-behavioural characteristics. Evaluation of local transmission epidemiology to characterize malaria risk is essential for planning malaria control and elimination programmes. The use of geographical information systems (GIS) techniques has been a major asset to this approach. To assess time and space distribution of malaria disease in Bandiagara, Mali, within a transmission season, data were used from an ongoing malaria incidence study that enrolled 300 participants aged under six years old ". Methods: Children's households were georeferenced using a handheld global position system. Clinical malaria was defined as a positive blood slide for Plasmodium falciparum asexual stages associated with at least one of the following signs: headache, body aches, fever, chills and weakness. Daily rainfall was measured at the local weather station. Landscape features of Bandiagara were obtained from satellite images and field survey. QGIS™ software was used to map malaria cases, affected and non-affected children, and the number of malaria episodes per child in each block of Bandiagara. Clusters of high or low risk were identified under SaTScan W software according to a Bernoulli model. Results: From June 2009 to May 2010, 296 clinical malaria cases were recorded. Though clearly temporally related to the rains, Plasmodium falciparum occurrence persisted late in the dry season. Two " hot spots " of malaria transmission also found, notably along the Yamé River, characterized by higher than expected numbers of malaria cases, and high numbers of clinical episodes per child. Conversely, the northeastern sector of the town had fewer cases despite its proximity to a large body of standing water which was mosquito habitat. Conclusion: These results confirm the existence of a marked spatial heterogeneity of malaria transmission in Bandiagara, providing support for implementation of targeted interventions. Background Malaria is one of the leading causes of morbidity and mortality in the world, with an estimated 3.3 billion people at risk of malaria [1]. The incidence of malaria worldwide is estimated to be 216 million cases per year, with 81% of these cases occurring in sub-Saharan Africa. Malaria kills approximately 655,000 people per year; 91% of deaths occur in sub-Saharan Africa [1], mostly in children under five years of age. In Mali, West Africa, malaria represents 36.5% of consultation motives in health center, it is a leading cause of morbidity and mortality children of less than five years of age and the first reason of anaemia in pregnant women [2]. Malaria transmission is seasonal. Malaria parasite transmission and clinical disease are characterized by important microgeographic variation, often between adjacent villages, households or families [3-8]. This local heterogeneity is driven by a variety of factors including human genetics [9,10], distance to potential breeding sites [11,12], housing construction
ISSN: 1475-2875

hal-01307672
https://hal-amu.archives-ouvertes.fr/hal-01307672
https://hal-amu.archives-ouvertes.fr/hal-01307672/document
https://hal-amu.archives-ouvertes.fr/hal-01307672/file/1475-2875-12-82.pdf
DOI : 10.1186/1476-072X-2-5

Éditeur(s) : HAL CCSD
Résumé : International audience
In the paper the following mixed equilibrium problem in a Hilbert space is considered: find x 2 C such that F(x, x)+hG(x), x−xi 0, 8x 2 C, where C is a nonempty convex closed subset of a real Hilbert space. For its solution a version of the proximal approach is studied. The general proximal method always includes a quadratic term of the kind |x−xn|2, which provides a process of transition from a point xn to a point xn+1. The authors replace this quadratic term by its linearization. Thus, they obtain a method of the kind F(xn+1, x)+hG(xn)+ −1(h 0(xn+1)−h 0(xk)), x−xn+1i 0, 8x 2 C, where h0 is the derivative of a given function on C. It is proved that if the function F(x, y) is monotone and convex in y for any x, F(x, x) = 0, and the operator G(x) is co-coercive, then the method weakly converges in a real Hilbert space to an equilibrium solution. Note that this result will also be true if the co-coercive condition is replaced by a monotonicity property. The Tikhonov regularization method (in the absence of disturbances and calculating auxiliary solutions approximately) is justified and its weak convergence in a Hilbert space is proved. It is known that the proximal method can always be interpreted as an implicit discret approximation of some differential equation or inclusion. Therefore the authors consider a differential inclusion for the extreme mapping. Permitting "-approximation for the function F(x, y) by means of a parametric family F(x, y, ") and assuming the strong monotonicity of the operator @F(x, y, ") (it is a very strong condition), the authors prove the convergence of the trajectory of the differential inclusion to an equilibrium solution.
Ill-posed variational problems and regularization techniques

hal-00773204
https://hal.univ-antilles.fr/hal-00773204

Éditeur(s) : HAL CCSD Society for Industrial and Applied Mathematics
Résumé : International audience
We present iterative methods for finding the critical points and/or the minima of extended real valued functions of the form $phi = psi+ g-h$, where $psi$ is a differentiable function and g and h are convex, proper, and lower semicontinuous. The underlying idea relies upon the discretization of a first order dissipative dynamical system which allows us to preserve the local feature and to obtain some convergence results. The main theorems not only recover known convergence results in this field but also provide a theoretical basis for the development of new iterative methods.
ISSN: 1052-6234

hal-00779987
https://hal.univ-antilles.fr/hal-00779987
DOI : 10.1137/060655183

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
We consider a bilevel problem involving two monotone equilibrium bifunctions and we show that this problem can be solved by a simple proximal method. Under mild conditions, the weak convergence of the sequences generated by the algorithm is obtained. Using this result we obtain corollaries which improve several corresponding results in this field.
ISSN: 0925-5001

hal-00776657
https://hal.univ-antilles.fr/hal-00776657
DOI : 10.1007/s10898-009-9476-1

Éditeur(s) : HAL CCSD
Résumé : International audience
In this note we study the convergence of a descent-proximal method for finding critical points of a DC function. From a practical point of view, we propose an algorithmic pattern obtained by coupling the latter with cutting plane approximations.
Journal of Applied Functional Analysis

hal-00815499
https://hal.univ-antilles.fr/hal-00815499

Éditeur(s) : HAL CCSD
Résumé : International audience
OBJECTIVE: Contemporary pesticides, such as triazines or organophosphates, possess immunotoxic properties. We aimed to determine whether prenatal environmental exposure to these current-use pesticides was associated with otitis media (OM) during the first 2 years of life among children from the PELAGIE mother-child cohort. METHODS: The PELAGIE cohort enrolled 3421 women at the beginning of pregnancy in Brittany (France). At the 2-year follow-up, 1505 families completed a self-administered questionnaire, including the domestic use of pesticides and consumption of organic diet during pregnancy and occurrences of OM in the child. Two health outcomes were considered: at least one OM and recurrent OM (at least three). Multivariate logistic regression models that adjusted for known risk factors of OM were performed. Metabolites of triazine herbicides and organophosphate insecticides measured in urine collected before the 19th week of gestation (248 mothers) were considered in a subgroup analysis. Multiple imputation was used to handle missing values for the covariates. RESULTS: Children whose mothers reported an organic diet during pregnancy had a reduced risk of OM (at least one episode, p trend=0.01). No association was found between any outcome and residential proximity to crops. The presence in maternal urine of dealkylated triazine metabolites (OR=2.12 (1.01 to 4.47)) was positively associated with recurrent OM. CONCLUSIONS: To the best of our knowledge, this is the first work to suggest a positive association between prenatal exposure to current-use pesticides and the occurrence of parent-reported OM in young children
Occupational and Environmental Medicine

hal-01201944
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01201944
DOI : 10.1136/oemed-2015-103039
PUBMED : 26347056

Éditeur(s) : HAL CCSD Heldermann
Résumé : International audience
We present an iterative method for finding zeroes of maximal monotone operators in a real Hilbert space. The underlying idea relies upon the discretization of a first order dissipative dynamical system which allows us to preserve the local feature, as well as to obtain convergence results. The main theorems do not only recover known convergence results of standard and inertial proximal methods, but also provide a theoretical basis for the application of new iterative methods.
Journal of Convex Analysis

hal-00780210
https://hal.univ-antilles.fr/hal-00780210

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
We introduce the notions of conditioning and well-posedness for equilibrium problems. Using these concepts, we obtain finite and strong convergence results for the proximal method that improve, develop, and unify several theorems in optimization and nonlinear analysis.
ISSN: 0163-0563

hal-00779994
https://hal.univ-antilles.fr/hal-00779994
DOI : 10.1080/01630560701766684

Éditeur(s) : HAL CCSD
Résumé : The purpose of this thesis is to improve the knowledge about and apply data mining techniques and some Bayesian model in the field of social and environmental health inequalities. On the neighborhood scale on the Paris, Marseille, Lyon and Lille metropolitan areas, the health event studied is infant mortality. We try to explain its risk with socio-economic data retrieved from the national census and environmental exposures such as air pollution, noise, proximity to traffic, green spaces and industries. The thesis is composed of two parts. The data mining part details the development of a procedure of creation of multidimensional socio-economic indices and of an R package that implements it, followed by the creation of a cumulative exposure index. In this part, data mining techniques are used to synthesize information and provide composite indicators amenable for direct usage by stakeholders or in the framework of epidemiological studies. The second part is about Bayesian models. It explains the "BYM" model. This model allows to take into account the spatial dimension of the data when estimating mortality risks. In both cases, the methods are exposed and several results of their usage in the above-mentioned context are presented. We also show the value of the socio-economic index procedure, as well as the existence of social inequalities of infant mortality in the studied metropolitan areas.
Cette thèse a pour but d'améliorer les connaissances concernant les techniques d'analyse de données et certains modèles bayésiens dans le domaine de l'étude des inégalités sociales et environnementales de santé. À l'échelle géographique de l'IRIS sur les agglomérations de Paris, Marseille, Lyon et Lille, l'événement sanitaire étudié est la mortalité infantile dont on cherchera à expliquer le risque avec des données socio-économiques issues du recensement et des expositions environnementales comme la pollution de l'air, les niveaux de bruit et la proximité aux industries polluantes, au trafic automobile ou aux espaces verts. Deux volets principaux composent cette thèse. Le volet analyse de données détaille la mise au point d'une procédure de création d'indices socio-économiques multidimensionnels et la conception d'un package R l'implémentant, puis la création d'un indice de multi-expositions environnementales. Pour cela, on utilise des techniques d'analyse de données pour synthétiser l'information et fournir des indicateurs composites utilisables directement par les décideurs publics ou dans le cadre d'études épidémiologiques. Le second volet concerne les modèles bayésiens et explique le modèle " BYM ". Celui-ci permet de prendre en compte les aspects spatiaux des données et est mis en œuvre pour estimer le risque de mortalité infantile. Dans les deux cas, les méthodes sont présentées et différents résultats de leur utilisation dans le contexte ci-dessus exposés. On montre notamment l'intérêt de la procédure de création d'indices socio-économiques et de multi-expositions, ainsi que l'existence d'inégalités sociales de mortalité infantile dans les agglomérations étudiées.
https://tel.archives-ouvertes.fr/tel-00943004

tel-00943004
https://tel.archives-ouvertes.fr/tel-00943004
https://tel.archives-ouvertes.fr/tel-00943004/document
https://tel.archives-ouvertes.fr/tel-00943004/file/Manuscrit_LallouA_final.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
To solve general variational inequalities considered in Robinson [9], we propose a generalized version of an algorithm introduced by Bermudez and Moreno [3]. Our results extend, improve and develop some known results in this field.
Advanced Modeling and Optimization

hal-00783892
https://hal.univ-antilles.fr/hal-00783892

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Relying on prox-regularity we suggest and analyze a class of iterative schemes for solving nonconvex variational inequalities, our result can be considered as an improvement and a significant extension of previously known results in this field.
ISSN: 0096-3003

hal-00780630
https://hal.univ-antilles.fr/hal-00780630
DOI : 10.1016/j.amc.2003.06.003

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: The evaluation of geographical healthcare accessibility in residential areas provides crucial information to public policy. Traditional methods - such as Physician Population Ratios (PPR) or shortest travel time - offer only a one-dimensional view of accessibility. This paper developed an improved indicator: the Index of Spatial Accessibility (ISA) to measure geographical healthcare accessibility at the smallest available infra-urban level, that is, the Ilot Regroupe pour des Indicateurs Statistiques. Methods: This study was carried out in the department of Nord, France. Healthcare professionals are geolocalized using postal addresses available on the French state health insurance website. ISA is derived from an Enhanced Two-Step Floating Catchment Area (E2FCA). We have constructed a catchment for each healthcare provider, by taking into account residential building centroids, car travel time as calculated by Google Maps and the edge effect. Principal Component Analyses (PCA) were used to build a composite ISA to describe the global accessibility of different kinds of health professionals. Results: We applied our method to studying geographical healthcare accessibility for pregnant women, by selecting three types of healthcare provider: general practitioners, gynecologists and midwives. A total of 3587 healthcare providers are potentially able to provide care for inhabitants of the department of Nord. On average there are 92 general practitioners, 22 midwives and 21 gynecologists per 100,000 residents. The composite ISA for the three types of healthcare provider is 39 per 100,000 residents. A comparative analysis between ISA and physician-population ratios indicates that ISA represents a more even distribution whereas the physician-population ratios show an 'all-or-nothing' approach. Conclusion: ISA is a multidimensional and improved measure, which combines the volume of services relative to population size with the proximity of services relative to the population's location, available at the smallest feasible geographical scale. It could guide policy makers towards highlighting critical areas in need of more healthcare providers, and these areas should be earmarked for further knowledge-based policy making.
ISSN: 1475-9276

hal-01359567
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359567
DOI : 10.1186/s12939-016-0411-z
PUBMED : 27485740

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: An environmental health inequality is a major public health concern in Europe. However just few studies take into account a large set of characteristics to analyze this problematic. The aim of this study was to identify and describe how socioeconomic, health accessibility and exposure factors accumulate and interact in small areas in a French urban context, to assess environmental health inequalities related to infant and neonatal mortality.Methods: Environmental indicators on deprivation index, proximity to high-traffic roads, green space, and healthcare accessibility were created using the Geographical Information System. Cases were collected from death certificates in the city hall of each municipality in the Nice metropolitan area. Using the parental addresses, cases were geocoded to their census block of residence. A classification using a Multiple Component Analysis following by a Hierarchical Clustering allow us to characterize the census blocks in terms of level of socioeconomic, environmental and accessibility to healthcare, which are very diverse definition by nature. Relation between infant and neonatal mortality rate and the three environmental patterns which categorize the census blocks after the classification was performed using a standard Poisson regression model for count data after checking the assumption of dispersion.Results: Based on geographic indicators, three environmental patterns were identified. We found environmental inequalities and social health inequalities in Nice metropolitan area. Moreover these inequalities are counterbalance by the close proximity of deprived census blocks to healthcare facilities related to mother and newborn. So therefore we demonstrate no environmental health inequalities related to infant and neonatal mortality.Conclusion: Examination of patterns of social, environmental and in relation with healthcare access is useful to identify census blocks with needs and their effects on health. Similar analyzes could be implemented and considered in other cities or related to other birth outcomes.
ISSN: 1476-069X

halshs-01366285
https://halshs.archives-ouvertes.fr/halshs-01366285
https://halshs.archives-ouvertes.fr/halshs-01366285/document
https://halshs.archives-ouvertes.fr/halshs-01366285/file/art_10.1186_s12940-016-0163-7.pdf
PUBMED : 27449640

Éditeur(s) : HAL CCSD
Résumé : International audience
Background: Everyone is subject to environmental exposures from various sources, with negative health impacts (air, water and soil contamination, noise...) or with positive effects (e.g. green space). Studies considering such complex environmental settings in a global manner are rare.Aims: We propose to use data mining techniques to create a composite exposure index with a data-driven approach, in view to assess the environmental burden experienced by populations. We illustrate this approach on a large French metropolitan area.Methods: The study was carried out in the Great Lyon area (France, 1,260,348 inhabitants in 2007, 527 km²) at the census block group (BG) scale. Indicators on NO2 annual concentrations, noise levels, proximity to green spaces and to industrial plants, and road traffic were synthetized using Multiple Factor Analysis (MFA), which allows to explore the relations between exposures and BGs without a priori knowledge, and to synthetize indicators of different types. Hierarchical clustering was then used to create BG classes. Results: The four first components of the MFA explained respectively 23, 14, 13 and 12% of the total variance. Clustering in 3 classes group: 1) BGs far from industries, greener and with less noise and air pollution than the average; 2) BGs close to industries with less green spaces and air pollution than the average; and 3)BGs far from industries but with higher levels of noise, air pollution and traffic. Greater numbers of classes were tested in order to assess a variety of clustering.Conclusions: We present a data driven approach using data mining techniques, which seem overlooked for cumulative exposure assessment in complex environmental settings. Although it cannot be applied directly for risk or health effect assessment, the resulting index can help to identify hot spots of cumulative exposure, to prioritize urban policies or to compare the environmental burden across study areas in an epidemiological framework.
Environment and Health – Bridging South, North, East and West. Conference of ISEE, ISES and ISIAQ.
Basel, Switzerland

hal-01432884
https://hal.archives-ouvertes.fr/hal-01432884
https://hal.archives-ouvertes.fr/hal-01432884/document
https://hal.archives-ouvertes.fr/hal-01432884/file/Poster_2013_ISEE_20130711.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
The author proposes a generalized proximal method for solving an equilibrium problem which consists in finding x 2 K such that F(x, y) 0, for all y 2 K, where K is a nonempty, convex and closed set of a real Hilbert space X, and F:K ×K !Ris a given bifunction with F(x, x) = 0 for all x 2 K. The weak convergence of the sequence generated by the method is proved under the assumptions of monotonicity and convexity, with respect to the second argument y (for every fixed x 2 K), of the bifunction F. Replacing the assumption of monotonicity with the one of strong monotonicity on F, a strong convergence result is obtained. A second strong convergence theorem is proved under the hypotheses of monotonicity and a new assumption of "co-Lipschitz continuity at 0" of the operator F. Applications to convex optimization, to the problem of finding a zero of a maximal monotone operator and to Nash equilibria problems are provided.
Journal of Natural Geometry

hal-00773194
https://hal.univ-antilles.fr/hal-00773194