Modeling of Self-Organizing Systems: An Overview

This paper gives a systematic overview on modeling formalisms suitable for modeling self-organizing systems. We distinguish between micro-level modeling and macro-level modeling. On the micro level, the behavior of each entity and the interaction between different object must be described by the model. Macrolevel modeling abstracts from the individual entities and only looks at the behavior of the system variables of interest. The differentiations between discrete and continuous time and between discrete and continuous state space lead to different descriptions of the model

Boltzmann-type models with uncertain binary interactions

In this paper we study binary interaction schemes with uncertain parameters for a general class of Boltzmann-type equations with applications in classical gas and aggregation dynamics. We consider deterministic (i.e., a priori averaged) and stochastic kinetic models, corresponding to different ways of understanding the role of uncertainty in the system dynamics, and compare some thermodynamic quantities of interest, such as the mean and the energy, which characterise the asymptotic trends. Furthermore, via suitable scaling techniques we derive the corresponding deterministic and stochastic Fokker-Planck equations in order to gain more detailed insights into the respective asymptotic distributions. We also provide numerical evidences of the trends estimated theoretically by resorting to recently introduced structure preserving uncertainty quantification methods

Modified hybrid genetic algorithm of discreet optimization problems

The goal objective is to improve the efficiency of solving discrete optimization problems. The proposed method refers to the “fast” methods and was named the “Local genetic method”. The peculiarity of this method is that the chromosomes do not encode the whole solution, but only a small part of the plan. Therefore, the method allows us introducing unary and binary operations that take into account the specific nature of the problem. The important feature of the method is the non-deterministic nature of the computation, which is due to the internal parallelism of computations and is expressed in the asynchronous action of various local strategies. In terms of speed, the proposed method in a number of experiments outperformed the traditional algorithm by more than 10 times and always found the best solution. The nature of the approximation to the optimum for these algorithms remained unchanged when solving any test cases

Évaluation pharmacoéconomique des thérapies efficaces et dispendieuses en prévention des maladies cardiovasculaires

Les maladies cardiovasculaires (MCV) ont une prévalence élevée dans le monde et sont considérées comme la deuxième cause de mortalité chez la population canadienne. Les statines sont reconnues comme le traitement par excellence dans la prévention des MCV. Toutefois, les statines ne conviennent pas à tous les patients, potentiellement, en raison de la survenue d’effets secondaires et du manque d’efficacité. Avec l’avancement de la science, de nouvelles thérapies voient le jour dans le milieu cardiovasculaire. Les inhibiteurs de la proprotéine convertase subtilisine-kexine de type 9 PCSK9 (iPCSK9) constituent un traitement efficace pour réduire les évènements cardiovasculaires. Cependant, ces thérapies sont dispendieuses pour le système de santé. Cette thèse a pour but d’explorer la pharmacoéconomie des thérapies dispendieuses ayant démontrées une efficacité clinique importante dans le traitement préventif des MCV. La pharmacoéconomie est un outil d’évaluation destiné aux décideurs ayant comme objectif d’optimiser l’utilisation des ressources humaines et financières. Tout d’abord, dans un premier article, nous avons évalué l’efficacité maximale d’une thérapie hypolipémiante à partir des grilles de risque cardiovasculaires. Selon les résultats obtenus, l’efficacité maximale qu’il est raisonnable d’espérer a correspondu à une diminution du risque relatif variant entre 0,46 et 0,66. Ensuite, dans un deuxième article, nous avons estimé l’efficacité d’une thérapie dispendieuse dans un contexte différent puisque les études cliniques étaient en cours. Avec l’aide d’un modèle de Markov, la propension à payer a été fixée à deux seuils distincts, alors que le coût d’acquisition de la thérapie est demeuré fixe. Nos résultats ont estimé que pour atteindre les seuils de propension à payer de 50 000 $et 100 000$ par année de vie ajustée pour la qualité, l’efficacité devrait être de 0,58 et 0,78 respectivement. Finalement, l’étude randomisée contrôlée établissant l’efficacité clinique des iPCSK9 a été publiée. Nous avons donc pu évaluer le coût-utilité réel des iPCSK9 avec une nouvelle méthode de simulation, nommée Conditions et évènements discrètement intégrés. Cette étude est l’objet 2 de mon troisième article. Les résultats de cet article ont estimé que l’iPCSK9 n’est pas coût-efficace selon l’efficacité obtenue dans les études cliniques. En conclusion, suite aux résultats présentés dans cette thèse rédigée par articles, il serait envisageable d’intégrer dans le modèle pharmacoéconomique l’option d’un test génétique afin d’individualiser le traitement de chaque patient.Cardiovascular diseases (CVD) have a high prevalence worldwide and are considered the second leading cause of death in the Canadian population. Statins are recognized to be the gold standard treatment in the prevention of CVD. However, statins are not suitable for all patients, potentially because of side effects and lack of efficacy. With the advancement of science, new therapies are emerging in the cardiovascular field. Inhibitors of proprotein convertase subtilisin-kexin type 9 (iPCSK9) have been shown to be effective in reducing cardiovascular events. However, these therapies are expensive. This article-based thesis aims to explore the pharmacoeconomics of expensive therapies that have demonstrated significant clinical efficacy in the preventive treatment of CVD. Pharmacoeconomics is an evaluation tool for decision-makers with the objective of optimizing the use of human and financial resources. In the first publication, we evaluated the maximum effectiveness of lipid-lowering therapy from cardiovascular risk grids. According to our results, this maximum expected benefit fluctuates between 0.46 and 0.66. In the second publication, we estimated the effectiveness of an expensive therapy. At the time of our second publication, the results of the randomized controlled trial evaluating the clinical efficacy of iPCSK9 had not been published yet. Therefore, we used a Markov model to estimate the necessary clinical efficacy of PCSK9 inhibitors to reach two arbitrarily selected willingness-to-pay (WTP) thresholds. Our results showed that an efficacy of 0.58 and 0.78 were necessary to reach WTP thresholds of $50,000 and$100,000 per quality-adjusted life years respectively. Once the clinical efficacy of iPCSK9 was published, we evaluated their cost-utility. This was the object of our third article and a new simulation method named Discretely Integrated Condition was used. Our results suggested that at the current price, the PCSK9 inhibitors were not cost-effective. Following the results presented in this article-based thesis, it would be of interest to integrate the option of a hypothetical genetic test into the pharmacoeconomic model. This genetic test would be able to identify good responders in order to optimize the treatment of each individual patient

On modeling of self-organizing systems

A goal of computing and networking systems is to limit ad-ministrative requirements for users and operators. A tech-nical systems should be able to configure itself as much as possible to increase the usability. This leads to the design of self-organizing systems. Self-organizing systems emerge as an increasingly important area of research, not only for computer networks but also in many other fields. For ana-lyzing properties of complex systems, a mathematical model for these systems may be useful. Whether a model with dis-crete time or with continuous time fits better, depends on the properties of the system and which analysis should be done in the model. In this paper we give a comparison be-tween discrete and continuous models and we give a formal definition for modeling continuous complex systems. Then this theory is applied to model slot-synchronization in wire-less networks

PREFACE

Self-organization plays a key architectural role for the future Internet. Self-organization will enhance flexibility and evolvability of organically growing, large-scale distributed systems, e.g., of large-scale pervasive computing systems such as wireless sensor networks. These statements could be proved by the technical program of the IWSOS 2006. Sixteen high-quality papers were selected by a thorough review process out of more than 70 submissions from 21 different countries. The technical program of the IWSOS 2006 was particularly covering application-oriented topics like: the dynamics of structured and unstructured overlays; self-organization in grids, peer-to-peer networks, wireless environments, and autonomic computing; and the application of self-organization for enhancing network management and routing. The program of the IWSOS 2006 has been supplemented, besides the social events and tutorials, by a poster session on the role of “Self-Organization in European Next Generation Internet ” and also by a Technical Discussion on “Performance Modeling of Self-Organizing Systems”. The two parts of the technical report on hand is used to make the contributions to the poster sessio