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Ensemble neural network approach for accurate load forecasting in a power system

Krzysztof Siwek, Stanisław Osowski, Ryszard Szupiluk (2009)

International Journal of Applied Mathematics and Computer Science

The paper presents an improved method for 1-24 hours load forecasting in the power system, integrating and combining different neural forecasting results by an ensemble system. We will integrate the results of partial predictions made by three solutions, out of which one relies on a multilayer perceptron and two others on self-organizing networks of the competitive type. As the expert system we will apply different integration methods: simple averaging, SVD based weighted averaging, principal component...

Enseñanza de la bioestadística en medicina.

M.ª Purificación Galindo Villardón (1996)

Qüestiió

Hasta hace tan sólo unos años, era característico en el profesional médico un profundo desconocimiento de la Metodología Estadística y su utilidad, un hecho claramente cuestionado. Gracias a la intensa labor divulgativa, la mayoría de los investigadores médicos reconocen ya la importancia de los Métodos Estadísticos. Contamos, al menos, con un notable cambio de actitud por parte de los investigadores médicos. Sin embargo, el papel adjuticado a la Estadística en los nuevos planes de estudio no está...

Entropy solution for anisotropic reaction-diffusion-advection systems with L1 data.

Mostafa Bendahmane, Mazen Saad (2005)

Revista Matemática Complutense

In this paper, we study the question of existence and uniqueness of entropy solutions for a system of nonlinear partial differential equations with general anisotropic diffusivity and transport effects, supplemented with no-flux boundary conditions, modeling the spread of an epidemic disease through a heterogeneous habitat.

Enumerated type semantics for the calculus of looping sequences

Livio Bioglio (2011)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

The calculus of looping sequences is a formalism for describing the evolution of biological systems by means of term rewriting rules. In this paper we enrich this calculus with a type discipline which preserves some biological properties depending on the minimum and the maximum number of elements of some type requested by the present elements. The type system enforces these properties and typed reductions guarantee that evolution preserves them. As an example, we model the hemoglobin structure and...

Enumerated type semantics for the calculus of looping sequences

Livio Bioglio (2011)

RAIRO - Theoretical Informatics and Applications

The calculus of looping sequences is a formalism for describing the evolution of biological systems by means of term rewriting rules. In this paper we enrich this calculus with a type discipline which preserves some biological properties depending on the minimum and the maximum number of elements of some type requested by the present elements. The type system enforces these properties and typed reductions guarantee that evolution preserves them. As an example, we model the hemoglobin structure...

Epidemiological Models and Lyapunov Functions

A. Fall, A. Iggidr, G. Sallet, J. J. Tewa (2010)

Mathematical Modelling of Natural Phenomena

We give a survey of results on global stability for deterministic compartmental epidemiological models. Using Lyapunov techniques we revisit a classical result, and give a simple proof. By the same methods we also give a new result on differential susceptibility and infectivity models with mass action and an arbitrary number of compartments. These models encompass the so-called differential infectivity and staged progression models. In the two cases we prove that if the basic reproduction ratio...

Epidemiological Models With Parametric Heterogeneity : Deterministic Theory for Closed Populations

A.S. Novozhilov (2012)

Mathematical Modelling of Natural Phenomena

We present a unified mathematical approach to epidemiological models with parametric heterogeneity, i.e., to the models that describe individuals in the population as having specific parameter (trait) values that vary from one individuals to another. This is a natural framework to model, e.g., heterogeneity in susceptibility or infectivity of individuals. We review, along with the necessary theory, the results obtained using the discussed approach....

Epidemiology of Dengue Fever: A Model with Temporary Cross-Immunity and Possible Secondary Infection Shows Bifurcations and Chaotic Behaviour in Wide Parameter Regions

Maíra Aguiar, Bob Kooi, Nico Stollenwerk (2008)

Mathematical Modelling of Natural Phenomena

Basic models suitable to explain the epidemiology of dengue fever have previously shown the possibility of deterministically chaotic attractors, which might explain the observed fluctuations found in empiric outbreak data. However, the region of bifurcations and chaos require strong enhanced infectivity on secondary infection, motivated by experimental findings of antibody-dependent-enhancement. Including temporary cross-immunity in such models, which is common knowledge among field researchers...

Equazione stocastica di dinamica di popolazioni di tipo preda-predatore

Sonia Chessa, Hisao Fujita Yashima (2002)

Bollettino dell'Unione Matematica Italiana

Si considera l'equazione stocastica che modellizza la dinamica di popolazioni di due specie di tipo preda-predatore sotto perturbazioni stocastiche. Si dimostrano in primo luogo l'esistenza e l'unicità della soluzione dell'equazione; per questo è essenziale introdurre una funzione ausiliaria con cui si costruiscono soluzioni approssimate. Si dimostra inoltre che, se non sono presenti perturbazioni stocastiche dovute alla stocasticità demografica, ma solo perturbazioni stocastiche rappresentanti...

Equilibrium transitions in finite populations of players

J. Miękisz (2006)

Banach Center Publications

We discuss stochastic dynamics of finite populations of individuals playing symmetric games. We review recent results concerning the dependence of the long-run behavior of such systems on the number of players and the noise level. In the case of two-player games with two symmetric Nash equilibria, when the number of players increases, the population undergoes multiple transitions between its equilibria.

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