Despite an increasing recognition of the need for an integrative approach to sustainable development, there remains a tendency for this to be anthropocentric. Attempts to govern sustainability are invariably focused on the pre-eminence of the human perspective and social systems in the pursuit of human goals. This often means either excluding or attempting to control the external environment rather than understanding and responding to it. This thesis explores more holistic approaches to governance that are based upon the need for an improved understanding about the interconnections between social, economic and ecological systems. It examines current literature on governance for sustainable development and systems thinking as applied to it, with specific reference to Socio-Technical Systems (STS), social learning about systems’ interrelations and the nature of public goods. On the basis of this analysis, a systemic conception of governance for sustainability is developed and translated into a provisional framework that can aid participatory social learning relating to sustainable development. Three initial Socio-Technical Systems (STS) case studies are drawn upon to populate the empty framework (the European Critical Electricity Infrastructure (ECEI), the Finnish security system and the transition of energy systems towards a post carbon society); these are then analysed thematically to derive common governance for sustainability criteria. The final modified framework is then applied to an in depth, and on-going, case study of food systems’ security and sustainability and a final discussion considers how this governance framework (GAME) might contribute to future holistic decision making for more sustainable Socio-Technical Systems. The multi-method GAME supports the generation of future scenarios and core sustainability criteria by multiple stakeholders; reflecting needs, capabilities and limits that can maintain systems’ equilibrium. It also implies a more normative governance for sustainability and a commitment to improved evidence-based decision-making that reflects systems’ complexity and contributes to bridging the gaps between science, policy and society. The GAME is currently being extended to incorporate the user-friendly geospatial representations of impacts.

L'augmentation des cas de surpoids et d'obésité dans les pays développés n'épargne désormais plus les pays émergents qui sont de plus en plus touchés par ce phénomène. J'ai comparé dans cette étude, deux stratégies de prévention de l'obésité en milieu scolaire entre un pays du développé, la France, et un pays émergent, l'Inde. En effet l'Inde qui a amorcé sa transition nutritionnelle, connaît une augmentation des cas de surpoids et d'obésité infantiles. Les nombreuses recherches sur les déterminants de l'obésité mettent aujourd'hui en lumière sa nature multifactorielle. A la piste génétique qui était auparavant privilégiée, s'ajoutent de nombreuses autres hypothèses explicatives mettant en évidence des facteurs psychologiques, sociaux, économiques, épigénétiques, biologiques, alimentaires, liés au rythme de vie (énumération non exhaustive). La pluralité de ces facteurs de risque fait de l'obésité un phénomène qui peut être qualifié de complexe. Pour comprendre cette complexité, je me suis référée à la « méthode » proposée par Edgar Morin (1990) pour conceptualiser et analyser la complexité à travers plusieurs principes directeurs. Ces principes permettent d'orienter le raisonnement entre pensée complexe et pensée simplifiante. Je les ai appliqués à l'analyse des stratégies nutritionnelles en milieu scolaire. Mes résultats révèlent d'une part que le paradigme de complexité permet aux enseignants de développer une stratégie nutritionnelle adaptée à la nature complexe de l'obésité. D'autre part, la stigmatisation de l'obésité, si elle est nécessaire pour déclencher une réelle prise de conscience de l'intérêt de la prévention globale, doit être limitée pour ne pas devenir contre-productive. Ces résultats permettent d'ouvrir de nombreuses perspectives pour améliorer la stratégie nutritionnelle dans chaque contexte étudié (français et indien), tant dans le domaine de la recherche que dans celui de la formation des enseignants. / Nowadays, overweight and obesity in developed countries are increasing even in developped countries. In this study, I compared two strategies for obesity prevention in schools between developed countries , France, and a developped country, India. Indeed India which started its nutritional transition, knows an increase in the cases of infantile overweights and obesity. Many researchs on the determinants of obesity clarifies today its multifactorial nature. To the genetic track which was privileged before, many other explanatory assumptions are added highlighting factors psychological, social, economic, epigenetic, biological, food, dependent to the rhythm of life (non exhaustive enumeration). The plurality of these risk factors shows that obesity is a phenomenon which can be qualified of complex. To understand this complexity, I referred to the « method » suggested by Edgar Morin (1990) to conceptualize and analyze complexity through several guiding principles. These principles make it possible to direct the reasoning between complex thought and simplifying thought. I applied them to the analysis of the nutritional strategies in school. My results reveal on the one hand that the paradigm of complexity lead the teachers to develop a nutritional strategy adapted to the complex nature of obesity. In addition, the stigmatization of obesity, which is necessary to start a real awakening of the interest of the total prevention, must be limited not to become against-productive. These results open many prospects to improve the nutritional strategy in each studied context (french and indian), in the field of research and in the field of teacher training.

[pt] Esta pesquisa tem o objetivo de examinar, sob o ponto de vista do comprador,um aspecto específico da sinergia comprador-fornecedor: avaliar a aplicação do Modelo Balanced Sourcing -Laseter, 1998- numa parceria de fornecimento de longo prazo. Foi realizado um estudo de caso entre duas empresas de grande porte, que comercializam onze mil produtos e tem suas relações comerciais regidas por um contrato, do tipo take or pay, de longo prazo -dez anos-. Os dados necessários para análise desta parceria de fornecimento foram coletados com base em um levantamento de documentos e pesquisa de campo na empresa compradora. O retrato da aliança entre as duas empresas foi elaborado por meio da Abordagem Sistêmica, que permitiu revelar aspectos intra-empresa compradora capazes de interferir na aplicação do Modelo Balanced Sourcing -Laseter, 1998-. / [en] This investigation intends to search, under the purchaser point of view, a specific synergy aspect of purchaser- vendor relationship, to evaluate the Balanced Sourcing Model -Laseter, 1998- usage in long term partnership agreement. A business study between two large companies has been developed,which includes an eleven-thousand product trade covered by a take or pay long term contract -ten years-. The necessary data for such supply partnership study have been obtained based on document and field survey performed in the purchaser offices. The overall picture of such agreement between the two companies has been prepared by means of a Systems Approach, which allowed to identify inner-purchase company aspects that might be able to interpose in usage of the Balanced Sourcing Model -Laseter, 1998-.

Alstom Transport, entreprise du transport ferroviaire français, s’interroge sur l’émergence de nouveaux usages dans les véhicules de transports publics urbains. Afin de répondre à cette question, l’approche systémique a été choisie comme cadre théorique. Cette approche permet d’interroger l’organisation du système individus-habitacle. Des observations participantes structurées ont été menées dans 12 villes (dans cinq pays). Le traitement des données combinant les méthodes quantitative et qualitative a permis de décrire le placement en fonction de deux échelles (l’échelle de l’habitacle et l’échelle de l’individu). L’importance dans l’organisation du système de la position assise et de la possibilité de s’adosser a été mis en évidence, ainsi qu’une organisation spatiale des activités des individus. Une forme d’usage potentiellement émergente a pu être observée. Celle-ci interroge une évolution possible de l’organisation de placement, et ouvre de nouvelles perspectives de recherche concernant l’organisation spatiale des activités. / The French rail transport company Alstom Transport inquires whether new usages are emerging in urban public transport vehicles. The systemic approach has been chosen as a theoretical frame to respond to this question. This approach enables to examine the organization of the individual-passenger compartment system. Structured observation has been conduct in 12 cities (5 countries). Data analysis combining qualitative and quantitative methodologies, allows describing the placement based on 2 scales (the passengers compartment and the individual). The sense of the sitting position and the possibility to lean on has been brought to light as well as the spatial organization of activities. A potentially emerging usage could be observed. It interrogates a possible evolution of the organization of placement, and opens new research perspectives regarding the spatial organization of activities.

ABSTRACT The subject of this doctoral thesis is a framework for building an industrial policy for sustainable competitiveness of the glass industry in the Czech Republic. Industrial policy and competitiveness do not have commonly accepted definitions. Concepts on definitions differ across nations, regions, stage of development and over time -- in short or long time. Coming from these problems there are questions connected with horizontal or sectoral level of application. Globalization is a challenge for industry, the environmental issues alike. On one hand side is there enormous growth of costs on the other growth of business opportunities. Systemic approach to analysis of the complex of business environment brought progress to solve problems connected with articulation integrated levels. A complete analysis of the glass industry enables to understandnot only problems but also challenges driving the industry. Quality of political environment and mutual collaboration with all the actors is crusial for next development of succesful sustainable growth of the national economy. There is not the question if to do the industrial policy or not; the question is: how to do it?

Introdução - O cruzamento do modal ferroviário com rodoviário em um mesmo nível é chamado de passagem de nível (PN), os quais apresentam baixa freqüência de acidentes, porém elevados índices de gravidade. No dia 08 de setembro de 2010, em Americana-SP, ocorreu acidente envolvendo dois trens e um ônibus em uma PN, com dez vítimas fatais e dezessete feridos, dos quais quatro foram registrados como acidentes de trabalho. Objetivo - Analisar origens imediatas e latentes desse acidente visando evitar ou minimizar as chances de ocorrência de eventos semelhante no futuro. Método - Estudo de caso que foi realizado através da pesquisa de artigos, livros, jornais e reportagens televisivas sobre o assunto. Após essa etapa, foram realizadas entrevistas com pessoas envolvidas no acidente, como canceleiros, motoristas de ônibus e maquinistas. O Modelo de Análise e Prevenção de Acidentes de Trabalho (MAPA), que propõe uma abordagem sistêmica do caso, foi usado na análise do evento. Resultados - O local é mal iluminado e com presença de construções que dificultam a visualização dos trens. Essa PN apresenta intenso tráfego de pedestres e de carros mesmo com o sinal fechado. O motorista informou que o sinal vermelho só foi acionado quando o ônibus já estava no meio da PN, instantes antes do choque. As condições de trabalho dos motoristas de ônibus e maquinistas são inadequadas com uma prática freqüente de horas extras e às vezes não é respeitado o intervalo legal de 11 horas entre uma jornada e outra. As barreiras presentes na PN eram apenas simbólicas. O sistema de comunicação entre canceleiros, motoristas e maquinistas é dependente da ação humana sendo considerado frágil. Os entrevistados afirmaram já ter presenciado acidentes em PN, confirmando a fragilidade do sistema. O acidente foi investigado pelo Instituto de Criminalística que considerou o motorista do ônibus culpado pela ocorrência, sendo atualmente objeto de processo criminal correndo o risco de ser condenado e preso. Conclusão - O acidente foi um evento complexo, com a interação entre, pelo menos os seguintes componentes: o sistema de transporte rodoviário urbano, com destaque para a ação do motorista do ônibus; o transporte ferroviário e o trabalho dos maquinistas dos trens; o sistema de controle da PN que envolve o trabalho dos canceleiros encarregados da sinalização de aproximação dos trens; a concepção, gestão e manutenção da segurança da PN, o sistema viário urbano que inclui a iluminação pública / Introduction - The railway crossing with the road on the same level is called Grade Crossing (GC), which present low incidence of accidents, however, when they happen, they usually present high rates of severity. On September 8th, 2010, in Americana-SP, there was an accident involving two trains and one bus on a GC, with ten people died and seventeen were injured, four of which were registered as work accident. Aim - To analyze the immediate and latent causes of the accident attempting to avoid or minimize the chances of similar events to happen in the future. Method Case study that was performed by means of research from articles, books, newspapers and TV reports about the subject. After this phase, interviews were carried out with people involved in the accident, like watchmen, bus drivers and train operators. The Model of Analysis and Prevention of Work Accidents (MAPA), which proposes a systemic approach of the event, was used as a guide. Results - The site is poorly lit and with the presence buildings that obstruct the visualization of the trains coming to it. This GC has intense traffic of pedestrians and cars when the traffic signal is closed. The driver said that the red traffic signal was only triggered when the bus was in the middle of GC, moments before the collision. The work conditions bus drivers and driver of train are inadequate with a frequent practice of overtime and sometimes not respected the legal range of 11 hours between one day and another. At the time the accident happened, there were only symbolic barriers. The system of communication among watchmen, bus drivers and train operators depends on the human action being considered weak. The people interviewed said they had seen accidents on GC, which confirmed the fragility of the system. The accident was investigated by the Institute of Forensic Science which has considered the bus driver guilty of the occurrence, nowadays being object of criminal procedure and may be condemned and arrested. Conclusion - The accident was a complex event, with the interaction among, at least: the system of urban road transport, especially the action of the bus driver; the rail transport and the work of trains operators; the control system of GC, that involves the work of watchmen that are responsible by traffic signal at the approaching of trains; those in charge of design, management and maintenance of safety issues in the GCs and those in charge of the urban road system that includes lighting

A pesca artesanal tem significativa importância para o Estado de Santa Catarina, onde existem cerca de 25 mil pescadores artesanais em atividade, os quais são responsáveis por 30% da produção catarinense de pescado. Entretanto, verifica-se a existência de problemas em relação à atividade, como a dificuldade de manutenção das colônias de pescadores, a concorrência da pesca industrial, a poluição, dentre outros. Para estudar esse processo, a área delimitada é a Praia da Pinheira, no município de Palhoça, região de colonização açoriana, que até os anos 1970 ainda era caracterizada como uma comunidade de pescadores. Conforme foram se implantando melhorias na infra-estrutura da região, ocorreram significativas mudanças sócioeconômicas, principalmente a crescente presença do turismo. Soma-se ao contexto a criação de uma unidade de conservação, o Parque Estadual da Serra do Tabuleiro, em 1975, o que pode ser mais um obstáculo para a sociedade local, na medida em que restringe o uso dos recursos naturais. Assim, o contexto sócio-econômico também contribui para um processo de vulnerabilidade dos pescadores. Há diversos entendimentos a respeito da permanência de populações tradicionais e suas formas de relações sócio-econômicas, sendo importante uma reflexão sobre este grupo social que preserva características consideradas tradicionais na sociedade contemporânea. Além disso, é relevante compreender as relações do setor pesqueiro com outras atividades econômicas. Nesse sentido, este trabalho aborda a complexidade da atividade pesqueira, através de um enfoque sistêmico que permite conhecer a evolução e diferenciação dos sistemas pesqueiros da Praia da Pinheira. A pesquisa revelou quatro fases distintas: o sistema pesqueiro indígena; o sistema pesqueiro de subsistência dos açorianos; o sistema pesqueiro de salga; e o sistema pesqueiro comercial e de prestação de serviços. Igualmente, com base em dados qualitativos e quantitativos foram caracterizados os atuais sistemas técnicos de captura utilizados na Praia da Pinheira, bem como os atuais tipos de pescadores do local. / The artisan fishing is of great importance for the state of Santa Catarina, where roughly 25 thousand artisan fishermen are currently working, which represents 30% of the local fishing production. However, some problems related to this activity can be detected, as the difficulty to maintain the fishermen community, the industrial fishing competition, pollution, among others. In order to study this process, the delimited area is the Praia da Pinheira, in the municipality of Palhoça, region of Azorean colonization, which up until 1970s was predominantly a fishermen community. Whereas some infrastructure improvements were implemented in this region, important socioeconomic changes came into place, primarily the increasing tourism activity. In addition, the creation of a conservation unity, the Parque Estadual da Serra do Tabuleiro, in 1975, what may represent a further obstacle to the local society, in the extent that it restrains the use of natural resources. Thus, the socioeconomic juncture increases the fishermen vulnerability. There is a variety of interpretations about the resistance by traditional populations and its forms of socioeconomic relations, being important to analyze these social groups that preserve the so called traditional features in the contemporary society. Besides, it is important to understand the relationship between the fishing sector and the other economic activities. In this sense, this work comes up to the complexity of the fishing activity, through a systemic approach that allows us to understand the evolution and differentiation of the fishing systems in the Praia da Pinheira. The research revealed four different stages: the Indian fishing system; the Azorean subsistence fishing system; the salga fishing system; and the commercial fishing system and of services. By the same token, based on the qualitative and quantitative data, the contemporary technical systems of capturing used in the Praia da Pinheira were characterized, as well as the local fishermen types.

A realidade agrária da Bocacosta na Guatemala, área tradicionalmente cafeeira, sofreu modificações importantes nos últimos anos. As crise do café em princípios de 1990 e 2000, concomitantemente com a firmação dos Acordos de Paz em 1996, foram decisivos para a transformação produtiva e social da região. Atualmente, podemos encontrar, integrados aos latifúndios de café tradicionais do modelo agroexportador e às grandes fazendas de gado, associações compostas por pequenos produtores de café, assentamentos de ex-guerrilheiros do conflito armado, comunidades de camponeses que regularizaram as terras, entre outros. São estes grupos que, conscientes do perigo do monocultivo de café, estão diversificando a produção. Neste contexto, o presente trabalho tem por objetivo analisar as dinâmicas sociais e produtivas da Bocacosta, proporcionando um melhor entendimento do panorama agrário atual. A partir de uma metodologia fundamentada em um instrumental de cunho sistêmico, a pesquisa busca analisar e diagnosticar os sistemas de produção implementados pelos agricultores da Bocacosta. Este estudo permitiu identificar cinco (5) sistemas agrários, que evoluiram e diferenciaram-se ao longo do tempo, e sete (7) sistemas de produção predominantes, praticados atualmente na região. A análise aprofundada de cada sistema de produção foi operacionalizada por meio de estudos de caso, escolhidos intencionalmente, a partir da pesquisa de campo e das entrevistas com os informante-chave. Constatou-se que o café, apesar de ainda ser predominante na realidade agrária da região, encontra-se em regressão na maioria dos estabelecimentos rurais, em razão da baixa rentabilidade. Igualmente, destaca-se a heterogeneidade nas estratégias adotadas pelas novas formas sociais, responsáveis pelas novas dinâmicas produtivas. A análise das informações evidencia a necessidade de elaborar políticas públicas de caráter social que elevem as condições de vida da população rural, bem como medidas que permitam efetivar a transição produtiva para outros cultivos e criações ou a diferenciação do produto no mercado. / The agrarian reality at Bocacosta in Guatemala, a traditionally coffee area, underwent significant changes in recent years. The coffee crisis of early 1990 and 2000, concurrently with the Peace Accords signing in 1996, were crucial for the productive and social transformation in the region. Currently, we can find, integrated with traditional agro-export model coffee lands and large livestock farms, associations composed of small coffee producers, ex-guerrillas settlements of armed conflict, peasant communities that regularized the land, among others. Are these groups that, aware of the danger of coffee monoculture, are diversifying the production. In this context, the present study aims to examine the social and productive dynamics at Bocacosta, providing a better understanding of the current agricultural background. From a methodology based on a systemic instrument, the research seeks to analyze and diagnose the farming systems implemented by farmers of Bocacosta. This study allowed to identify five (5) agrarian systems, which evolved and differed over time, and seven (7) predominant farming systems, currently performed in the region. A detailed analysis of each farming system was carried out through case studies, intentionally chosen from the research field stage and interviews with key informers. We found out that coffee, despite still being dominant in the agricultural reality of the region, is declining in most of rural establishments, due to low profitability. Also, it can be highlight the heterogeneity of strategies adopted by the new social forms, responsible for new dynamic production. Analysis of the data illustrates the necessity to develop social-nature public policies that increase living conditions of rural population, as well as procedures to shift production to other crops and livestock or product differentiation on the marketplace.

Introdução - O cruzamento do modal ferroviário com rodoviário em um mesmo nível é chamado de passagem de nível (PN), os quais apresentam baixa freqüência de acidentes, porém elevados índices de gravidade. No dia 08 de setembro de 2010, em Americana-SP, ocorreu acidente envolvendo dois trens e um ônibus em uma PN, com dez vítimas fatais e dezessete feridos, dos quais quatro foram registrados como acidentes de trabalho. Objetivo - Analisar origens imediatas e latentes desse acidente visando evitar ou minimizar as chances de ocorrência de eventos semelhante no futuro. Método - Estudo de caso que foi realizado através da pesquisa de artigos, livros, jornais e reportagens televisivas sobre o assunto. Após essa etapa, foram realizadas entrevistas com pessoas envolvidas no acidente, como canceleiros, motoristas de ônibus e maquinistas. O Modelo de Análise e Prevenção de Acidentes de Trabalho (MAPA), que propõe uma abordagem sistêmica do caso, foi usado na análise do evento. Resultados - O local é mal iluminado e com presença de construções que dificultam a visualização dos trens. Essa PN apresenta intenso tráfego de pedestres e de carros mesmo com o sinal fechado. O motorista informou que o sinal vermelho só foi acionado quando o ônibus já estava no meio da PN, instantes antes do choque. As condições de trabalho dos motoristas de ônibus e maquinistas são inadequadas com uma prática freqüente de horas extras e às vezes não é respeitado o intervalo legal de 11 horas entre uma jornada e outra. As barreiras presentes na PN eram apenas simbólicas. O sistema de comunicação entre canceleiros, motoristas e maquinistas é dependente da ação humana sendo considerado frágil. Os entrevistados afirmaram já ter presenciado acidentes em PN, confirmando a fragilidade do sistema. O acidente foi investigado pelo Instituto de Criminalística que considerou o motorista do ônibus culpado pela ocorrência, sendo atualmente objeto de processo criminal correndo o risco de ser condenado e preso. Conclusão - O acidente foi um evento complexo, com a interação entre, pelo menos os seguintes componentes: o sistema de transporte rodoviário urbano, com destaque para a ação do motorista do ônibus; o transporte ferroviário e o trabalho dos maquinistas dos trens; o sistema de controle da PN que envolve o trabalho dos canceleiros encarregados da sinalização de aproximação dos trens; a concepção, gestão e manutenção da segurança da PN, o sistema viário urbano que inclui a iluminação pública / Introduction - The railway crossing with the road on the same level is called Grade Crossing (GC), which present low incidence of accidents, however, when they happen, they usually present high rates of severity. On September 8th, 2010, in Americana-SP, there was an accident involving two trains and one bus on a GC, with ten people died and seventeen were injured, four of which were registered as work accident. Aim - To analyze the immediate and latent causes of the accident attempting to avoid or minimize the chances of similar events to happen in the future. Method Case study that was performed by means of research from articles, books, newspapers and TV reports about the subject. After this phase, interviews were carried out with people involved in the accident, like watchmen, bus drivers and train operators. The Model of Analysis and Prevention of Work Accidents (MAPA), which proposes a systemic approach of the event, was used as a guide. Results - The site is poorly lit and with the presence buildings that obstruct the visualization of the trains coming to it. This GC has intense traffic of pedestrians and cars when the traffic signal is closed. The driver said that the red traffic signal was only triggered when the bus was in the middle of GC, moments before the collision. The work conditions bus drivers and driver of train are inadequate with a frequent practice of overtime and sometimes not respected the legal range of 11 hours between one day and another. At the time the accident happened, there were only symbolic barriers. The system of communication among watchmen, bus drivers and train operators depends on the human action being considered weak. The people interviewed said they had seen accidents on GC, which confirmed the fragility of the system. The accident was investigated by the Institute of Forensic Science which has considered the bus driver guilty of the occurrence, nowadays being object of criminal procedure and may be condemned and arrested. Conclusion - The accident was a complex event, with the interaction among, at least: the system of urban road transport, especially the action of the bus driver; the rail transport and the work of trains operators; the control system of GC, that involves the work of watchmen that are responsible by traffic signal at the approaching of trains; those in charge of design, management and maintenance of safety issues in the GCs and those in charge of the urban road system that includes lighting

Aujourd'hui en France, l'évaluation de la performance de stratégies de sécurité à déployer pour mettre un bâtiment en sécurité vis-à-vis de l'incendie repose sur une étude d'ingénierie en sécurité incendie. Cette étude a pour objectif l'estimation du risque incendie pour différentes stratégies, et pour des scénarios d'incendies jugés pertinents. Pour parvenir à cette estimation, le Centre Scientifique et Technique du Bâtiment français (CSTB) a mis au point un outil de simulation appelé SCHEMA-SI. Cet outil utilise des réseaux de Petri prédicat-transition différentiels orientés objets et des simulations de Monte Carlo pour générer de multiples scénarios d'incendie. Ces scénarios sont ensuite utilisés pour évaluer le risque incendie encouru avec une stratégie de sécurité. La stratégie est alors jugée d'autant plus performante que le risque incendie est faible. L'objectif de la thèse consiste à contribuer au développement d'une méthode d'analyse de risque incendie utilisant l'outil de simulation SCHEMA-SI. La réflexion a débuté par la définition de ce que devrait être cette méthode. A ce stade, il est apparu que l'une des difficultés que la méthode doit surmonter est celle de la mise en donnés du problème par un groupe d'acteurs impliqués dans la sécurité incendie du bâtiment étudié. Pour résoudre cette difficulté, une méthode de modélisation spécifique a été construite. Cette méthode, baptisée ISI-Systema, repose sur deux fondements principaux : d'une part, un langage graphique de modélisation permettant au groupe d'acteurs de réfléchir à la mise en données du problème en s'appuyant sur une approche systémique ; d'autre part, une démarche de traduction des modèles graphiques obtenus avec le langage systémique en réseaux de Petri compatibles avec SCHEMA-SI.Enfin, une application pratique de cette méthode de modélisation est proposée. / Nowadays in France, building fire safety strategy performance analysis relies on a fire engineering study. This kind of study aims at calculating fire risk for several strategies and for fire scenarios judged as relevant. In order to achieve risk calculation, the French Scientific and technical Building Center (CSTB) has developed a simulation tool called SCHEMA-SI. This tool is based on object-oriented differentiai predicate-transition Petri nets and on Monte Carlo simulations and is built to generate a large number of fire scenarios. Obtained scenarios are hence used to evaluate fire risk related to the strategy to evaluate. The lower the fire risk is obtained, the more efficient the strategy is considered. This thesis aims at contributing to the development of a SCHEMA-SI based fire risk assessment method. This thesis starts by a definition of what this method should be. At this stage, it appears that one of the difficulties to overcome is the one of the problem definition by a group of fire safety concerned people. In arder to solve this difficulty, a modeling method has been developed. This method, so-called ISI-Systema, relies on two main basements: in on hand, on a graphic modeling language created to allow a group of people to think about the problem definition by using a systemic approach ; on the other hand, on a SCHEMA-SI compatible Petri net - graphic model translation procedure. At last, a case study is proposed.