Alassane Bah

Land Policies for Climate Change Adaptation in West Africa A Multilevel Companion Modeling Approach

Based on 10 years of participatory modeling experience, the authors developed a multilevel participatory modeling process that links national policy makers, local councils, and grassroots stakeholders using a combination of games and computerized simulations. The challenge was to allow the target groups to design and evaluate collective adaptations to climate change that combine new collective rules for local, regional, and national regulations. This article details and highlights the novelty of the methodological process, which allows stakeholders to codesign frameworks for their own behaviors and rules. The experiment uses games and models with soft rules and the stakeholders themselves incorporate their own perceptions both in the board and computerized games. This was shown to be an efficient way to reach assessments and proposals that are shared between local stakeholders and policy makers, and should thus help improve the design of policies to face up to climate changes.

Numerical treatment of a nonlocal model for phytoplankton aggregation

Abstract 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 numerical solutions for parameters values corresponding to real conditions in nature. The numerical results emphasize the role of the nonlinear chemotaxis term in producing aggregating patterns and further, they are used to explore the asymptotic behavior of the model.

An Agent-Based Implementation of the Todaro Model

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 unemployment. In this paper, we build up an economic behavioral model of rural-urban migration which is an agent-based version of the analytical Todaro model described by deterministic ordinary differential equations. The agent-based model allows to explore the rural-urban labor migration process and give quantitative results on the equilibrium proportion of the labor force that is not absorbed by the modern industrial economy.

Megamodel-based Management of Dynamic Tool Integration in Complex Software Systems.

The development of complex software systems is more and more based on the composition and integration of autonomous component systems. This can be done either statically (proactive approach) at development-time or dynamically through a reactive approach in which a new composite system can possibly be created on-demand and/or at run-time from existing systems. With the aim of constructing and managing such complex and reactive software systems, we propose a megamodelbased environment supporting dynamic tool integration. Such an environment must therefore be consistent at any time (i.e. before, during and after an integration) and should also have to exhibit some self-* properties (such self management, selfhealing and self-configuration). In order to meet these challenges we propose the use of Hoare’s Axiomatic Semantics and some inference rules to maintain the integrity of the megamodel and its components. For that we have defined a formal-safe execution as well as an execution semantic for each operation likely to modify the megamodel contents.

Prior Data Quality Management in Data Mining Process

Data Mining (DM) projects are implemented by following the knowledge discovery process. Several techniques for detecting and handling data quality problems such as missing data, outliers, inconsistent data or time-variant data, can be found in the literature of DM and Data Warehousing (DW). Tasks that are related to the quality of data are mostly in the Data Understanding and in the Data Preparation phases of the DM process. The main limitation in the application of the data quality management techniques is the complexity caused by a lack of anticipation in the detection and resolution of the problems. A DM process model designed for the prior management of data quality is proposed in this work. In this model, the DM process is defined in relation to the Software Engineering (SE) process; the two processes are combined in parallel. The main contribution of this DM process is the anticipation and the automation of all activities necessary to remove data quality problems.

NUMERICAL SIMULATIONS OF A NONLINEAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATION MODELING PHYTOPLANKTON AGGREGATION

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 solutions for parameter values corresponding to real conditions in nature. Further, a comparison is made with two deterministic versions of the SPDE, that are advection–diffusion equations with linear and nonlinear reaction terms, to emphasize the efficiency of the stochastic equation in modeling the aggregation behavior in phytoplankton.

Ontological Modeling Approach for Statistical Databases Publication in Linked Open Data

At the level of the National Statistical Institutes (NSI), there is a large volume of data which is generally in a format which conditions the method of publication of the information they contain. Data collection projects for households or businesses are increasingly integrating into their implementation phase, a platform for results dissemination. If not, it is the NSI Web portals that are often used for dissemination. Thus, these dissemination methods previously used, and do not promote rapid access to information and especially does not offer the option of being able to link data for in-depth processing. In this paper, we present an approach to modeling these data to publish them in a format intended for the Semantic Web. Our objective is to be able to publish all this data in a single platform and offer the option to link with other external data sources. An application of the approach will be made on data from major national surveys such as the one on employment, poverty, child labor, and the general census of the population of Senegal.

An Y MDE Approach for Enactable Software Process Models Generation.

The advent of MDE enabled to automate software development while reducing its production time. While software companies need continually to improve and customize their software processes, an automated approach to do so is still lacking. Most of those companies have an organizational process that is used whenever they have an upcoming development project. Reusing the same process for any development project is somehow inadequate. So, tailoring of such a process is necessary to fit organisational and operational companies’ needs. However, even if that tailored process can be used for a specific project, it still lacks resources needed for execution. In this short paper, we propose a Y model-based approach that allows tailoring software processes and generating enactable software process models by using models transformations. We defined metamodels to express models involved in those transformations. We illustrate our approach with an extract of the UWE Process which we adapt and instantiate for a development project with .Net

An Agent Based Model for Studying the Impact of Rainfall on Rift Valley Fever Transmission at Ferlo (Senegal)

In this paper, we created a conceptual model UML (unified modelling language) showing interactions between animals, mosquitoes, environment, and climate factors. The UML static model was used to build an agent-based model that helps to study the impact of rainfall variability on the number of infected hosts after the outbreak of Rift valley fever. Several simulations were done on the multi-agent CORMAS platform. The different results showed continued growth in infections during the rainy season. A sensitivity analysis taking into account the delayed rains and dry spells have allowed us to know a clear vision about the rate of infected animals due to the rainfall variability. This work defines a framework for studying the impact of climatic changes on vector-borne diseases.

Using the SPEM 2.0 kind-based extension mechanism to define the SPEM4MDE metamodel

The objective 1 of the OMGs standard SPEM is to propose shared concepts for describing software and even systems processes. The SPEM 2.0 metamodel proposes concepts that are quite generic to describe model-driven development processes. Indeed, the artifacts of those processes are essentially models and relationships between them are numerous (e.g. impact, matching, overlap and so on). We notice that is difficult to have a process modeling language that is suitable to define any kind of process including MDE ones. To overcome this lack, we propose in this paper an extension of SPEM4MDE based on the SPEM 2.0 kind-based extension mechanism. It allows process designer to refine SPEM concepts in order to define the model-driven processes. To illustrate our approach, the MDE-based VUML process for models composition has been used.