Nadjia El Saadi- PhD in Applied Mathematics(Pau University, France)
- Professor (Full) at National Higher School of Statistics and Applied Economics, Algiers, Algeria
Nadjia El Saadi
- PhD in Applied Mathematics(Pau University, France)
- Professor (Full) at National Higher School of Statistics and Applied Economics, Algiers, Algeria
About
39
Publications
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143
Citations
Introduction
Current institution
National Higher School of Statistics and Applied Economics, Algiers, Algeria
Current position
- Professor (Full)
Additional affiliations
December 2012 - present
The National High School of Statistics and Applied Economics
Position
- Professor (Full)
Publications
Publications (39)
In this paper, we develop an agent-based model (ABM) to study malaria disease transmission. This ABM is a host-vector model where hosts are humans and vectors are the female Anopheles mosquitos, moreover the ABM is spatially explicit integrating aquatic habitats in which mature vectors breed and the immature vectors develop. The dispersals of vecto...
We present an agent-based labor market model that incorporates worker internal migration. We examine at the labor markets of two regions: the origin region and the destination region. The characteristics of the workers, as well as the features of the regions in which they live, are taken into account. The model describes the individual’s life cycle...
Industrial clustering can be considered as a result of two types of forces: the centripetal force, which encourages the concentration of the manufacturing activities, and centrifugal force, which acts in the opposite direction. To explain the agglomeration process, we develop an agent-based version of Krugman model (1991) which allows us considerin...
The objective of this paper is to analyze the efficiency of a spatial moments model (SMM) in approximating an individual-based model (IBM) dedicated to the study of the aggregation phenomenon in a phytoplankton population. The dynamic system of spatial moments consists of a system of integro-differential equations derived from a phytoplankton IBM....
Mini-Congrès des Mathématiciens Algériens (MCMA 2021) organisé par la Société Mathématique d'Algérie en collaboration avec l'Université de M'sila et l'ENS de Bou Saâda qui se tiendra le 27 et 28 octobre 2021 en distanciel.
Pour plus de détails nous vous prions de visiter la page de l'événement: http://www.smath.dz/act/mcma2021/
In this article, we investigate the question of the impact of the diel vertical migration (DVM) and the light attenuation by the cells on both spatial pattern and population dynamics of phytoflagellates. For these purposes, we performed a simulation study by using a spatially explicit individual-based model (IBM). The designed IBM includes 2 global...
In this paper, we develop an agent-based model (ABM) to simulate the sylvatic transmission of the parasite T. cruzi, causative agent of Chagas disease (also called American trypanosomiasis). This ABM incorporates host-vector interactions, demographical processes for both hosts and vectors, and also vector and host dispersals. We implement the ABM u...
We construct an agent-based economic model that is capable of reproducing the mechanisms of internal migration of workers by focusing on the auto-selective characteristic of the subject-matter. Our model considers the potential of people to migrate as well as those who do migrate. Thus, the model introduces a pre-selection stage into the act of mig...
Spatial patterns in biological populations and their effect on ecological interactions are central topics in mathematical ecology. The aim of this work is to study the aggregation phenomenon in a population of phytoplankton using the dynamical model of spatial moments. The latter is developed from an individual-based model (IBM) of phytoplankton th...
The phytoplankton's spatial aggregation is a very important phenomenon that can give responses to many questions such as the passage from the unicellularity to the multicellularity. In this work, we are interested by predator-induced aggregations in motile phytoplankton. Our aim is to bring, through a simulation study, some explanations on how thes...
We propose an agent-based model to simulate internal migration of workers. The model is based on mathematical equations describing the socio-economic characteristics of the agents and their behaviors. The main assumption of the model is the objective of individuals to find decent (formal) employment. The model simulates the migration of agents from...
Cet article examine l'impact des économies d'agglomération sur le choix de la localisation des activités industrielles en Algérie. Nous avons, à cet effet, utilisé des données sur l'emploi, concernent le secteur industriel (NAP80), de la période allant de 2001 à 2012 [1,2,13] 1. Les résultats montrent que les entreprises ont tendance à choisir des...
In this paper, we develop a 3D-individual-based model (IBM) to understand effect of various small-scale mechanisms in phytoplankton cells, on the cellular aggregation process. These mechanisms are: spatial interactions between cells due to their chemosensory abilities (chemotaxis), a molecular diffusion and a demographical process. The latter is co...
The proposed migration model of workers considers migration as a multifactorial and multidi-mensional phenomenon. Multifactorial because it considers economic and socio-demographic aspects in the decision to migrate in the two regions concerned by migration (origin and desti-nation), and multidimensional because it integrates micro and macroeconomi...
The goal of this study is to analyze the dynamics underlying Algiers urban area formation with
reference to The New Economic Geography (NEG) theories and more precisely to the paper of Paul
Krugman (1991), "Increasing returns and economic geography" which explains the mechanisms of
economic activities concentration through two types of forces: cent...
In this paper, we are interested in the numerical simulation of a nonlinear stochastic partial differential equation (SPDE) arising as a model of phytoplankton aggregation. This SPDE consists of a diffusion equation with a chemotaxis term and a branching noise. We develop and implement a numerical scheme to solve this SPDE and present its numerical...
In this paper, we are interested in the analytical study of a nonlinear
Stochastic Partial Differential Equation (SPDE) arising as a model of
phytoplankton aggregation. This SPDE consists in a diffusion equation with a
chemotaxis term responsible of self-attraction of phytoplankton cells and a
multiplicative branching noise. Existence of mild solut...
The goal of this study is to analyze the dynamics underlying Algiers urban
area formation with reference to The New Economic Geography (NEG) theories and
more precisely to the paper of Paul Krugman (1991), "Increasing returns and
economic geography" which explains the mechanisms of economic activities
concentration through two types of forces: cent...
Le rôle des agrégations de phytoplancton est bien reconnu de nos jours mais les mécanismes et dynamiques qui gouvernent leur formation ne sont pas encore clairs. Ce travail est une contribution dans cette direction. Il présente la construction d'un modèle mathématique stochastique qui décrit rigoureusement la formation des agrégations de phytoplanc...
In this paper, we are interested in the numerical treatment of a nonlinear model describing phytoplankton aggregation. The model consists in an integro-differential diffusion equation, with a chemotaxis term responsible for self-attraction of phytoplankton cells. We develop and implement a numerical scheme to solve this nonlinear PDE and present nu...
Les cinq dernières décennies ont connu une littérature abondante sur les migrations internes au sein des pays en développement. Depuis les travaux fondateurs de Lewis (1954) et Harris et Todaro (1970) stipulant que la première explication de l'effort de migration est la quête d'un meilleur revenu, de nouvelles variables ont été intégrées au modèle...
The problem of internal migration and its effect on urban unemployment and underemployment has been the subject of an abundant
theoretical literature on economic development. However, most discussions have been largely qualitative and have not provided
enough rigorous frame-works with which to analyze the mechanism of labor migration and urban unem...
In this paper, we use an individual-based model (IBM) in order to study the aggregation of phytoplankton cells. The model describes the movements of cells and also the cells’ division and their death. The movement of a phytoplankton cell is based on an Itô stochastic differential equation with a drift term describing the spatial interactions of the...
The aim of this work is to provide a stochastic mathematical model of aggregation in phytoplankton, from the point of view of modelling a system of a large, but finite number of phytoplankton particles that are subject to random dispersal modeled as Brownian motions, mutual interactions allowing the particles motions some dependance and branching (...
International audience
The aim of this work is to provide a stochastic mathematical model of aggregation in phytoplankton, from the point of view of modelling a system of a large but finite number of phytoplankton cells that are subject to random dispersal, mutual interactions allowing the cell motions some dependence and branching (cell division o...
In this paper, we build up an individual-based model (IBM) that describes the aggregative behavior in phytoplankton. The processes in play at the individual level (an individual=a phytoplankton cell) are: a random dispersal, a displacement due to the net effect of cells present in a suitable neighborhood (spatial interactions) and a branching (cell...
The mechanisms of grouping and the models revolving around these problems truly impassioned many mathematicians. Our main goal in this paper is the development and analysis of an aggregation model of phytoplankton. The model is the continuum limit of an interacting particle model describ-ing a "long-ranged" aggregation mechanism among particles. It...
Our main goal in this paper is the development and analysis of an aggregation model of phytoplankton. The model consists of an integro-differential advection-diffusion equation, with convolution term. The Cauchy problem is well posed in a suitable function space. Existence, uniqueness and positivity of solutions are investigated.
Le rôle des agrégations du phytoplancton dans les chaînes alimentaires marines et dans les processus de transport vertical du carbone est bien reconnu de nos jours. Beaucoup de travaux récents ont montré l'existence et l'importance de la formation de ces grandes particules mais les mécanismes et les dynamiques qui gouvernent leur formation ne sont...
Questions
Questions (9)
I need a biological literature addressing the effects of T. cruzi infection on the survival, maturation and fertility of Triatominae.
I am asking if there is a biological literature addressing the question of dying or recovering from T. cruzi infection in Triatominae which are the vectors causing Chagas disease.
Triatoma sanguisuga, which are species of sylvatic triatominae are known to disperse
in search of hosts to feed on. For a simulation study, I need numerical values for the daily distances travelled by an adult T. sanguisuga.
We need to know how new firms are created and if thre are works that describe thoroughly this process.
In the biological litterature, it is reported that female T. sanguisuga develops eggs in her ovarioles, but does not deposit them until she has been fertilized and has received a blood meal. Suppose that this triatoma has been fertilized but blood meals are rare (for instance, no availibility of hosts on which to feed), can this female reproduce in these conditions?
We need experimental data on effects of competition between phytoplankton cells on the spatial and temporal evolution of a phytoplankton population. More precisely, we are interested by motile species of phytoplankton such as dinoflagcellates.
In fact, I need such values especially for T. Sanguisuga for a simulation study.
For instance, are there some references about the calculation of the invasion speed of a disease using an IBM?
The paper has been published in arXiv: math.PR/0511512 v1 ,21 Nov 2005. I would like to know if there is a published final version.
