Formal Visual Modeling of Real-Time Systems in e-Motions: Two Case Studies

e-Motions is an Eclipse-based visual timed model transformation framework with a Real-Time Maude semantics that supports the usual Maude formal analysis methods, including simulation, reachability analysis, and LTL model checking. e-Motions is characterized by a novel and powerful set of constructs for expressing timed behaviors. In this paper we illustrate the use of these constructs --- and thereby implicitly investigate their suitability to define real-time systems in an intuitive way --- to define and formally analyze two prototypical and very different real-time systems: (i) a simple round trip time protocol for computing the time it takes a message to travel from one node to another, and back; and (ii) the EDF scheduling algorithm.Comment: In Proceedings AMMSE 2011, arXiv:1106.596

Multi-level Modeling as a Society of Interacting Models

We propose to consider a multi-level representation from a multi-modeling point of view. We define a framework to better specify the concepts used in multi-level modeling and their relationships. This framework is implemented through the AA4MM meta-model, which benefits from a middleware layer. This meta-model uses the multi-agent paradigm to consider a multi-model as a society of interacting models. We extend this meta-model to consider multi-level modeling and present a proof of concept of a collective motion example where we show the ability of this approach to rapidly change from one pattern of interaction to another one by reusing some of the meta-model's components

Determination of the optimal age to vaccinate against dengue using a tetravalent dengue vaccine in Brazil

Dengue is endemic in most of the subtropics and tropics with half of the world's population at risk of acquiring an infection. For decades only mosquito control could aid with disease prevention. However, in December 2015 the first dengue vaccine, Dengvaxia, became available.;In this thesis a single-serotype transmission model considering the effect of vaccination is derived. Three different assumptions regarding the biting rate are made. Initially, a constant biting rate is assumed to determine the optimal vaccination age for Brazil. For a more accurate description of the dynamics, mosquito biting rate data is used later on to determine an age-dependent rate.;Lastly, instead of determining the force of infection from the biting rate, agedependent serological data is used to estimate both of these functions. The description of the human population dynamics is also improved upon by using a step-death function rather than a constant death rate.;In order to reduce the burden of dengue, the optimal vaccination age is defined to minimise the lifetime expected risk of hospitalisation or lethality. For both risk functions several theories and uncertainties surrounding the disease outcome and the effect of vaccination are studied. The impact of antibody dependent enhancement and permanent cross-immunity on the vaccination age is determined. Additionally, a vaccine-induced increase is incorporated for the risk of hospitalisation. All possible serotype combinations are considered.;The results of this work demonstrate that the optimal vaccination age depends on how the biting rate and force of infection are defined. A variety of different optimal ages for immunisation are found. These vary with the assumptions relating to serotype cross-reactions and depend particularly on whether a vaccine-induced risk is considered. Consequently, a better understanding of the disease and the effect of the vaccine is paramount for finding an accurate optimal age for dengue immunisation.Dengue is endemic in most of the subtropics and tropics with half of the world's population at risk of acquiring an infection. For decades only mosquito control could aid with disease prevention. However, in December 2015 the first dengue vaccine, Dengvaxia, became available.;In this thesis a single-serotype transmission model considering the effect of vaccination is derived. Three different assumptions regarding the biting rate are made. Initially, a constant biting rate is assumed to determine the optimal vaccination age for Brazil. For a more accurate description of the dynamics, mosquito biting rate data is used later on to determine an age-dependent rate.;Lastly, instead of determining the force of infection from the biting rate, agedependent serological data is used to estimate both of these functions. The description of the human population dynamics is also improved upon by using a step-death function rather than a constant death rate.;In order to reduce the burden of dengue, the optimal vaccination age is defined to minimise the lifetime expected risk of hospitalisation or lethality. For both risk functions several theories and uncertainties surrounding the disease outcome and the effect of vaccination are studied. The impact of antibody dependent enhancement and permanent cross-immunity on the vaccination age is determined. Additionally, a vaccine-induced increase is incorporated for the risk of hospitalisation. All possible serotype combinations are considered.;The results of this work demonstrate that the optimal vaccination age depends on how the biting rate and force of infection are defined. A variety of different optimal ages for immunisation are found. These vary with the assumptions relating to serotype cross-reactions and depend particularly on whether a vaccine-induced risk is considered. Consequently, a better understanding of the disease and the effect of the vaccine is paramount for finding an accurate optimal age for dengue immunisation