Dans l’industrie de l’avionique, les Générateurs Automatiques de Code (GAC) sont de plus en plus utilisés pour produire des parties du logiciel embarqué. Puisque le code généré fait partie d’un logiciel critique, les standards de sûreté exigent une vérification approfondie du GAC: la qualification. Dans cette thèse en collaboration avec AdaCore, nous cherchons à réduire le coût des activités de test par des méthodes automatiques et efficaces.La première partie de la thèse aborde le sujet du test unitaire qui assure une exhaustivité élevée mais qui est difficile à réaliser pour les GACs. Nous proposons alors une méthode qui garantit le même niveau d’exhaustivité en n’utilisant que des tests d’intégration de mise en œuvre plus facile. Nous proposons tout d’abord une formalisation du langage ATL de définition du GAC dans la théorie des Transformations Algébriques de Graphes. Nous définissons ensuite une traduction de postconditions exprimant l’exhaustivité du test unitaire en des préconditions équivalentes qui permettent à terme de produire des tests d’intégration assurant le même niveau d’exhaustivité. Enfin, nous proposons d’optimiser l’algorithme complexe de notre analyse à l’aide de stratégies de simplification dont nous mesurons expérimentalement l’efficacité.La seconde partie du travail concerne les oracles de tests du GAC, c’est à dire le moyen de valider le code généré par le GAC lors d’un test. Nous proposons un langage de spécification de contraintes textuelles capables d’attester automatiquement de la validité du code généré. Cette approche est déployée expérimentalement à AdaCore pour le projet QGen, un générateur de code Ada/C à partir de Simulink®. / In the avionics industry, Automatic Code Generators (ACG) are increasingly used to produce parts of the embedded software. Since the generated code is part of critical software, safety standards require a thorough verification of the ACG called qualification. In this thesis in collaboration with AdaCore, we seek to reduce the cost of testing activities by automatic and effective methods.The first part of the thesis addresses the topic of unit testing which ensures exhaustiveness but is difficult to achieve for ACGs. We propose a method that guarantees the same level of exhaustiveness by using only integration tests which are easier to carry out. First, we propose a formalization of the ATL language in which the ACG is defined in the Algebraic Graph Transformation theory. We then define a translation of postconditions expressing the exhaustiveness of unit testing into equivalent preconditions that ultimately support the production of integration tests providing the same level of exhaustiveness. Finally, we propose to optimize the complex algorithm of our analysis using simplification strategies that we assess experimentally.The second part of the work addresses the oracles of ACG tests, i.e. the means of validating the code generated by the ACG during a test. We propose a language for the specification of textual constraints able to automatically check the validity of the generated code. This approach is experimentally deployed at AdaCore for a Simulink® to Ada/C ACG called QGen.

Résumé Le taux de mortalité infantile est un indicateur de santé des populations et de l'efficacité des systèmes de santé. Il est également capable d'estimer l'ampleur des inégalités sociales et en matière de santé entre populations. Au cours des 30 dernières années, le Brésil a enregistré des réductions significatives des taux de mortalité infantile. Entre 1990 et 2017, le taux de mortalité des moins de cinq ans est passé de 53,7 décès pour mille naissances vivantes à 15,6. Une réduction de 71% sur la période. La moyenne nationale de réduction était de 6% par an dans les années 90, passant à 4,8% dans les années 2000 et à 3,2% par an entre 2011 et 2015. De nombreux facteurs ont été signalés comme la cause de ces améliorations. Malgré la mise en œuvre de politiques sociales et de santé qui ont eu un impact positif sur la santé des populations brésiliennes au cours des dernières décennies, depuis 2009 le pays a connu une lente diminution de la baisse de la mortalité infantile qui est restée à des niveaux élevés, enregistrant de grandes disparités régionales. Après une crise économique qui a évolué vers une période troublée de crise politique, le pays a enregistré en 2016 une augmentation de la mortalité infantile chez les moins d'un an et de cinq ans, qui est passé de 12,43 à 12,72 décès pour mille naissances vivantes et de 14,28 décès à 14,89 décès pour mille naissances vivantes, respectivement. Ces éléments attirent l'attention sur l'impact possible des déterminants sociaux de la santé sur les taux de mortalité infantile au Brésil après la mise en œuvre de ces politiques sociales et de santé. Cette anomalie observée dans la tendance de la mortalité infantile, combinée aux disparités régionales et à une lente diminution de la baisse des taux de mortalité infantile est préoccupante. Elle soulève des questions sur l'impact de ces politiques sociales et de santé, sur la capacité du pays à maintenir une réduction du taux de mortalité infantile à long terme, et sa capacité à rejoindre les taux des pays développés, ainsi quels sont les déterminants de la mortalité infantile au Brésil après la mise en œuvre de ces politiques publiques? L'objectif premier de cette thèse était d'identifier les déterminants de la mortalité infantile au Brésil après la mise en œuvre du programme Stratégie Santé Famille et du Programme Bolsa Família afin de formuler des hypothèses plausibles, relatives au ralentissement du taux de mortalité chez les moins d’un an et de cinq ans, aux disparités régionales et à l’anomalie observée dans la tendance à la baisse du taux de mortalité infantile au Brésil. Pour atteindre cet objectif, nous avons effectué trois études: 1) un examen de la portée qui visait à identifier et à résumer les déterminants de la mortalité infantile au Brésil sous l'influence de ces programmes, en vue de formuler des hypothèses relativement à l’évolution récente des taux de mortalité infantile au Brésil et d’identifier les lacunes, en termes de recherche, concernant les déterminants de la mortalité infantile dans le pays; 2) une analyse descriptive rétrospective, dans une optique de santé publique et des inégalités en matière de santé, en adoptant le cadre analytique proposé par la Commission de l'OMS sur les déterminants sociaux de la santé, en utilisant les données du taux de mortalité chez les enfants de moins d'un an et des possibles déterminants de la mortalité infantile au Brésil selon les conclusions de notre examen de la portée (article 1); 3) une proposition de méthodologie pour faire face aux défis liés au développement d'un modèle de données de panel en utilisant des données agrégées des 26 états brésiliens et des différentes sous-régions, selon le « Conceptual Model of Health Capability » , afin d'inférer des associations possibles entre nos variables indépendantes et les taux de mortalité infantile au Brésil et pour vérifier l'hypothèse soulevée dans l'examen de cadrage sur les récents changements des indicateurs de mortalité infantile du pays. Les résultats globaux de ces études ont démontré qu'à la lumière du « Conceptual Model of Health Capability » et des déterminants sociaux de la santé, les disparités régionales liées aux inégalités, notamment aux niveaux du revenu, de l'éducation, de l'emploi, du taux de fécondité, de l'accès et de la qualité des services de santé, expliquent les inégalités en termes de taux de mortalité infantile, en particulier dans les macro-régions du nord et du nord-est du pays, ce qui freine probablement la baisse du taux de mortalité infantile. Ces inégalités expliqueraient à la fois la lenteur de la réduction du taux de mortalité infantile et sa tendance à demeurer à des niveaux relativement élevés. Les résultats ont également montré que les variations de ces facteurs, pour des raisons liées à la crise économique et politique, ont probablement perturbé la tendance à la baisse des taux de mortalité infantile. À cet égard, les résultats suggèrent qu'une forte réduction du taux d'emploi, observée entre 2014 et 2015 entre autres facteurs, pourrait avoir eu un impact différé sur le TMI en 2016. Les résultats ont également permis d’établir une association entre l'emploi et différents indicateurs de mortalité infantile, le taux d'emploi pouvant avoir un impact sur la mortalité infantile jusqu'à trois ans. Enfin, les études ont démontré qu'il existe un seuil de revenu des ménages, qui agit comme facteur de protection contre la mortalité infantile, en dessous duquel plus la proportion de ménages est élevée, plus le risque d'augmentation de la mortalité infantile est élevé. / Abstract The infant mortality rate is an indicator of population health and the effectiveness of health systems that is also capable of estimating the extent of social and health inequalities between populations. Over the last 30 years, Brazil has recorded significant reductions in child mortality rates. Between 1990 and 2017, the under-five mortality rate dropped from 53.7 to 15.6 deaths per thousand live births, a 71% reduction over the period. The national reduction average was 6% per year in the 1990s, decreasing to 4.8% in the 2000s and to 3.2% per year between 2011 and 2015, and many factors have been reported as the cause of these improvements. Even after the implementation of health and social policies that positively affected the health of the populations in Brazil in the last decades, since 2009 the country has experienced a slow decrease in the decline in infant mortality that remained at high levels, registering great regional disparities. After an economic crisis that evolved into a troubled period of political crisis, in 2016 the country recorded increases in under-one-year infant mortality and under-five-year infant mortality rates, that raised from 12.43 deaths to 12.72 deaths per thousand live births and from 14.28 deaths to 14.89 deaths per thousand live births, respectively. These facts call attention to the possible impact of social determinants of health on infant mortality rates in Brazil after the implementation of these health and social policies. This anomaly in the trend of child mortality, particularly when combined with regional disparities and a slow decrease in the decline in infant mortality rates is of great concern and raise questions about what is the extent of these health and social policies on the country’s ability to maintain a longer-term decline in the infant mortality rate, is it capable of placing this rate at the level of developed countries and what are the determinants of infant mortality in Brazil after the implementation of these public policies. The overarching goal of this thesis was to identify the determinants of infant mortality in Brazil after the implementation of the Family Health Strategy and the Bolsa Família programs in order to raise plausible hypotheses for the slowdown, the regional disparities, and the anomaly observed in the trend of declines in the infant mortality rate in Brazil. To attain this objective, we conducted three research papers: 1. a scoping review that aimed at identifying and summarizing the determinants of infant mortality in Brazil under the influence of Family Health Strategy and Bolsa Família programs, with a view of raising hypothesis for the recent changes in the infant mortality rates in Brazil and identifying gaps in terms of research concerning the determinants of infant mortality in the country, 2. a descriptive retrospective analysis according to the perspective of Public Health and health inequalities by adopting the analytical framework proposed by the World Health Organization’s Commission on Social Determinants of Health, using data from under-one-year old infant mortality rate and from possible determinants of infant mortality in Brazil according to the findings of our scoping review (article 1), and 3. a methodological proposal in order to overcome the challenges to developing a panel data model using aggregated data from the 26 Brazilian states and different subregions according to the Conceptual Model of Health Capability, with a view of inferring possible associations between our independent variables and infant mortality rates in Brazil, aiming at reviewing the hypothesis raised in the scoping review about the recent changes in the country's infant mortality indicators. The global results of these studies demonstrated that in the light of the Conceptual Model of Health Capability and the social determinants of health, regional disparities related to inequalities in factors such as income, education, employment, fertility rate, access, and quality of health services, account for inequalities in infant mortality rates, especially in the north and Northeast macro-regions of the country, which likely hamper further reductions of infant mortality. Those inequalities would explain both the slowdown in the reduction and the tendency of the infant mortality rate to remain at relatively high levels. Results also demonstrated that variations in those factors for reasons relating to the economic and political crisis, likely have interrupted the secular trend of declining infant mortality rates. In this regard, results suggest that a sharp reduction in employment rate observed between 2014 and 2015, among other factors, may have had a delayed impact on infant mortality rates in 2016. The results also identified an association between employment and different infant mortality indicators, with employment rate possibly impacting child mortality up to three years. Finally, the studies have shown that a household income threshold acts as a protective factor against child mortality, the bigger the proportion of households below this income bracket, the greater the risk of an increase in child mortality.

Traffic safety has been considered one of the most important issues in the transportation field. With consistent efforts of transportation engineers, Federal, State and local government officials, both fatalities and fatality rates from road traffic crashes in the United States have steadily declined from 2006 to 2011.Nevertheless, fatalities from traffic crashes slightly increased in 2012 (NHTSA, 2013). We lost 33,561 lives from road traffic crashes in the year 2012, and the road traffic crashes are still one of the leading causes of deaths, according to the Centers for Disease Control and Prevention (CDC). In recent years, efforts to incorporate traffic safety into transportation planning has been made, which is termed as transportation safety planning (TSP). The Safe, Affordable, Flexible Efficient, Transportation Equity Act - A Legacy for Users (SAFETEA-LU), which is compliant with the United States Code, compels the United States Department of Transportation to consider traffic safety in the long-term transportation planning process. Although considerable macro-level studies have been conducted to facilitate the implementation of TSP, still there are critical limitations in macroscopic safety studies are required to be investigated and remedied. First, TAZ (Traffic Analysis Zone), which is most widely used in travel demand forecasting, has crucial shortcomings for macro-level safety modeling. Moreover, macro-level safety models have accuracy problem. The low prediction power of the model may be caused by crashes that occur near the boundaries of zones, high-level aggregation, and neglecting spatial autocorrelation. In this dissertation, several methodologies are proposed to alleviate these limitations in the macro-level safety research. TSAZ (Traffic Safety Analysis Zone) is developed as a new zonal system for the macroscopic safety analysis and nested structured modeling method is suggested to improve the model performance. Also, a multivariate statistical modeling method for multiple crash types is proposed in this dissertation. Besides, a novel screening methodology for integrating two levels is suggested. The integrated screening method is suggested to overcome shortcomings of zonal-level screening, since the zonal-level screening cannot take specific sites with high risks into consideration. It is expected that the integrated screening approach can provide a comprehensive perspective by balancing two aspects: macroscopic and microscopic approaches.

Recently, there has been a surge in the research and application of "Green energy" in the United States. This has been driven by the following three objectives: (1) to reduce the nation's reliance on foreign oil, (2) to mitigate emission of greenhouse gas, and (3) to create an economic stimulus within the United States. Switchgrass is the biomass of choice for the Southeastern United States. In this dissertation, we address a feedstock logistics problem associated with the delivery of switchgrass for conversion into biofuel. In order to satisfy the continual demand of biomass at a bioenergy plant, production fields within a 48-km radius of its location are assumed to be attracted into production. The bioenergy plant is expected to receive as many as 50-400 loads of biomass per day. As a result, an industrialized transportation system must be introduced as early as possible in order to remove bottlenecks and reduce the total system cost. Additionally, we assume locating multiple bioenergy plants within a given region for the production of biofuel. We develop mixed integer programming formulations for the feedstock logistics problem that we address and for some related problems, and we solve them either through the use of decomposition-based methods or directly through the use of CPLEX 12.1.0. The feedstock logistics problem that we address spans the entire system-from the growing of switchgrass to the transporting of bio-crude oil, a high energy density intermediate product, to a refinery for conversion into a final product. To facilitate understanding, we present the reader with a case study that includes a preliminary cost analysis of a real-life-based instance in order to provide the reader appropriate insights of the logistics system before applying optimization techniques for its solution. First, we consider the benefits of active versus passive ownership of the production fields. This is followed by a discussion on the selection of baler type, and then, a discussion of contracts between various business entities. The advantages of storing biomass at a satellite storage location (SSL) and interactions between the operations performed at the production field with those performed at the storage locations are then established. We also provide a detailed description of the operations performed at a SSL. Three potential equipment options are presented for transporting biomass from the SSLs to a utilization point, defined in this study as a Bio-crude Plant (BcP). The details of the entire logistics chain are presented in order to highlight the need for making decisions in view of the entire chain rather than basing them on its segments. We model the feedstock logistics problem as a combination of a 2-level facility location-allocation problem and a multiple traveling salesmen problem (mATSP). The 2-level facility location-allocation problem pertains to the allocation of production fields to SSLs and SSLs to one of the multiple bioenergy plants. The mATSP arises because of the need for scheduling unloading operations at the SSLs. To this end, we provide a detailed study of 13 formulations of the mATSP and their reformulations as ATSPs. First, we assume that the SSLs are always full, regardless of when they are scheduled to be unloaded. We, then, relax this assumption by providing precedence constraints on the availability of the SSLs. This precedence is defined in two different ways and, is then, effectively modeled utilizing all the formulations for the mATSP and ATSP. Given the location of a BcP for the conversion of biomass to bio-crude oil, we develop a feedstock logistics system that relies on the use of SSLs for temporary storage and loading of round bales. Three equipment systems are considered for handling biomass at the SSLs, and they are either placed permanently or are mobile, and thereby, travel from one SSL to another. We use a mathematical programming-based approach to determine SSLs and equipment routes in order to minimize the total cost incurred. The mathematical program is applied to a real-life production region in South-central Virginia (Gretna, VA), and it clearly reveals the benefits of using SSLs as a part of the logistics system. Finally, we provide a sensitivity analysis on the input parameters that we used. This analysis highlights the key cost factors in the model, and it emphasizes areas where biggest gains can be achieved for further cost reduction. For a more general scenario, where multiple BcPs have to be located, we use a nested Benders' decomposition-based method. First, we prove the validity of using this method. We, then, employ this method for the solution of a potential real-life instance. Moreover, we successfully solve problems that are more than an order of magnitude larger than those solved directly by CPLEX 12.1.0. Finally, we develop a Benders' decomposition-based method for the solution of a problem that gives rise to a binary sub-problem. The difficulty arises because of the sub-problem being an integer program for which the dual solution is not readily available. Our approach consists of first solving the integer sub-problem, and then, generating the convex hull at the optimal integer point. We illustrate this approach for an instance for which such a convex hull is readily available, but otherwise, it is too expensive to generate for the entire problem. This special instance is the solution of the mATSP (using Benders' decomposition) for which each of the sub-problems is an ATSP. The convex hull for the ATSP is given by the Dantzig, Fulkerson, and Johnson constraints. These constraints at a given integer solution point are only polynomial in number. With the inclusion of these constraints, a linear programming solution and its corresponding dual solution can now be obtained at the optimal integer points. We have proven the validity of using this method. However, the success of our algorithm is limited because of a large number of integer problems that must be solved at every iteration. While the algorithm is theoretically promising, the advantages of the decomposition do not seem to outweigh the additional cost resulting from solving a larger number of decomposed problems. / Ph. D.

El moteado del níspero, causado por el hongo Fusicladium eriobotryae es la principal enfermedad que afecta al cultivo del níspero, produciendo pérdidas importantes en la cosecha en los años con condiciones climáticas adecuadas. Sin embargo, no existen estudios sobre la epidemiología y el control de esta enfermedad, por lo que éstos constituyen el principal objetivo de la presente Tesis. Para ello, se va ha caracterizar in vitro y en campo la influencia de las principales variables climáticas en el desarrollo de F. eriobotryae, desarrollándose ecuaciones matemáticas que modelicen esta relación. Por otro lado, se va a llevar a cabo un modelo epidemiológico para el moteado del níspero capaz de predecir, en función de las principales variables climáticas el riesgo de infección. Además, se realizará un estudio del control de la enfermedad que comprenderá, por un lado, la evaluación in vitro y en planta de la efectividad de las principales materias activas utilizadas para el control del moteado del níspero, y por otro la evaluación del grado de resistencia de una colección de aislados de F. eriobotryae a DMI y Metil-Tiofanato y la caracterización molecular de la misma. / González Domínguez, E. (2014). Biology, epidemiology and control of Fusicladium eriobotryae, causal agent of loquat scab [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/38715

This thesis presents work on a holistic approach for improving the overall design of solar cooling systems driven by solar thermal collectors. Newly developed methods for thermodynamic optimization of hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show an 81% increase of the Solar Cooling Efficiency (SCEth) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSEth) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSEth with the already established COPth of the chiller, leads to the SCEth factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems. Furthermore, the definition of a coefficient of performance, including irreversibilities from energy conversion (COPcon), enables a direct comparison of compression and sorption chiller technology. This new performance metric is applicable to all low-temperature heat-supply machines for direct comparison of different types or technologies. The achieved findings of this work led to an optimized generic design for solar cooling systems, which was successfully transferred to the market.

No description available.

This thesis presents work around 3 themes: dark energy, gravitational waves and Bayesian inference. Both dark energy and gravitational wave physics are not yet well constrained. They present interesting challenges for Bayesian inference, which attempts to quantify our knowledge of the universe given our astrophysical data. A dark energy equation of state reconstruction analysis finds that the data favours the vacuum dark energy equation of state $w {=} -1$ model. Deviations from vacuum dark energy are shown to favour the super-negative ‘phantom’ dark energy regime of $w {< } -1$, but at low statistical significance. The constraining power of various datasets is quantified, finding that data constraints peak around redshift $z = 0.2$ due to baryonic acoustic oscillation and supernovae data constraints, whilst cosmic microwave background radiation and Lyman-$\alpha$ forest constraints are less significant. Specific models with a conformal time symmetry in the Friedmann equation and with an additional dark energy component are tested and shown to be competitive to the vacuum dark energy model by Bayesian model selection analysis: that they are not ruled out is believed to be largely due to poor data quality for deciding between existing models. Recent detections of gravitational waves by the LIGO collaboration enable the first gravitational wave tests of general relativity. An existing test in the literature is used and sped up significantly by a novel method developed in this thesis. The test computes posterior odds ratios, and the new method is shown to compute these accurately and efficiently. Compared to computing evidences, the method presented provides an approximate 100 times reduction in the number of likelihood calculations required to compute evidences at a given accuracy. Further testing may identify a significant advance in Bayesian model selection using nested sampling, as the method is completely general and straightforward to implement. We note that efficiency gains are not guaranteed and may be problem specific: further research is needed.

No description available.

I. An original methodological discussion is proposed on the problem of the typology of tropical rain forest’s plant communities, based on the study of forest types across gradients of continentality and elevation, within Atlantic central Africa. These investigations were based on the statement that the main problems in forest typology are related to the non-zonal or zonal character of the different vegetation types and to non considering the relations and differences between forest strata. II. Field data consisted in phytosociological homogeneous sample plots localized within different recognized phytogeographical entities, in a region of tropical Africa where these entities are known to be well conserved. A total of 37 such plots were inventoried in the region extending from the littoral forests of Ndoté, Equatorial Guinea, which are wet evergreen forests, to the continental forests of the Dja, Cameroon, known as evergreen seasonal forests. The studied region also included the oriental Atlantic forests of Equatorial Guinea, known as moist evergreen forests or caesalp forests. In various parts of this continentality gradient, some plots were localized within climax non-zonal formations, namely the submontane rain forests. The emphasis was put on the vegetation of the Monte Alén National Park. The sampling methodology was willing to be as "complete ", including all strata, "quantitative ", enumerating all individuals, and "representative ", within each stratum, as possible. These multi-layers plots were realised using nested sub-plots, with a sampling size of 100 individuals for every ligneous stratum recognized (dominant trees, dominated trees and shrubs) and a sampling size of 200m² for the herbaceous and suffrutex stratum. Forest types were defined independently for each stratum and the differences were analysed. A method was proposed for the simultaneous analysis of all floristic data, converting and standardizing the values from ligneous strata, on the one hand, and from understorey strata, on the other hand. III. Ten forest types were described using IndVal and discussed in the general context of the guineo-congolian region, from a syntaxonomic view point (agglomerative classification) and from a phytogeographical view point (divisive classification). Homologies between these two approaches are described. The proposed phytogeographical system is based on an "open " conception of hierarchical classifications, combining advantages of agglomerative and divisive classifications. In concrete terms, the non-zonal criteria, for example the submontane variants, are categorised separately and in analogy with the zonal criteria, related to the usual phytochoria. Analysis of ecological relationships for the 10 communities showed that the main variables related to the floristic variability in our mainland rain forests are elevation, rainfall, hygrometry (estimated using bryophytes cover levels) and distance to the ocean. The two extremes on the vertical microclimatic gradient, dominant trees stratum and herbaceous stratum, give similar typologies, however canonical analysis showed that for the herbaceous layer, non-zonal variables (hygrometry and elevation) were gaining more importance when the influence of the two zonal variables was attenuated. In every case, spatial autocorrelation was less important than the environment in explaining floristic variability but its role increased in the spatial arrangement of understorey species, whose dispersal capacity is generally lower than canopy trees. The phytosociological, phytogeographical and ecological description of forest types is accompanied by a physiognomical description using biological types spectrum, as well as architectural models, leaf sizes, etc. With regard to diversity, we have demonstrated that species richness was higher from upper to lower strata because of the accumulation in lower strata of species from various strata. On the other hand, the proper stratum diversity, i.e. the structural set, decreased from dominant trees to shrubs. The proper diversity of the herb layer showed relatively high figures mainly due to the higher individual density in relation to the existence of microstrata. Within the 37 sample plots, 1,050 taxa have been identified to species or morpho-species levels, for a total of 25,750 individuals. These taxa represent 442 genus among 104 families. The richest forest type is found on the foothills of the Niefang range, on the windward side. This forest type is also characterised by a high number of oligotypic genus and by species belonging to functional types indicators of glacial refuges. These functional types are defined on the basis of the dispersal capacity and on kind of stand needed for effective germination. We formulated the hypothesis that this kind of "foothills refuge ", characterised by his zonal nature, could have been one of the rare refuges for species from mainland rain forests, while montane and fluvial refuges would mainly have preserved species from non-zonal forest types: (sub)montane and riverine. Based on indicator species of submontane forests, a potential distribution map of this forest type has been realised at the Atlantic central African scale. More than 400 submontane forest localities have been mapped. These forests begin at 400m of altitude near the ocean, and progressively at higher altitude for increasing distance to the ocean. Many lowland localities also comprised submontane species, which could indicate the existence of ecological transgressions. These transgressions would allow migratory tracks for submontane species between isolated mountain ranges, not only during glacial periods, through heights at the northern and southern borders of the congo basin, but also contemporarily through the lowland riverine forest network, in the centre of this basin. Finally, a special attention has been attributed to littoral forests and to some cases of choroecological transgressions, coupled to the ecological equalization phenomenon.