Les travaux présentés dans cette thèse portent sur la définition du paradigme de régénération issu des principes du développement durable et de l’économie circulaire. L’idée est de limiter l’épuisement des ressources de la sphère naturelle en exploitant les gisements de «déchets» de la sphère technique et en diminuant la production de déchets. La notion de régénération émerge d’une analogie entre la sphère naturelle et la sphère technique, et fait apparaitre les concepts de «nutriments» et de «décomposeurs». Le concept de nutriment permet de revisiter la fin de vie d’équipements domestiques ou industriels, en les voyant comme des nutriments techniques capables de nourrir certaines filières industrielles après transformation. Ces transformations sont opérées par des décomposeurs dans le milieu naturel, et des régénérateurs dans le milieu industriel. Quatre types de régénérateurs ont été définis. Pour chaque type de régénérateurs, des exigences sur le produit devant être satisfaites par les produits «déchets» sont identifiées afin d’assurer la régénération de ces produits. D’autres exigences ont été définies au niveau du processus de régénération pour spécifier les actions de régénération. Ces deux types d’exigences doivent être maintenus tout au long du cycle de vie du produit. La maintenance a été identifiée comme le processus fondamental pour surveiller et maintenir au travers du temps la capacité de régénération et ainsi prolonger la durée de vie des produits. Lorsque les régénérateurs mettent en place une stratégie de régénération, il est nécessaire d’évaluer sa faisabilité. Nous avons donc proposé un outil d’aide à la décision, en modélisant d’une part le comportement du produit au cours de son cycle de vie, ainsi que le comportement des régénérateurs, et d’autre part l’effet des exigences sur le produit et sur le processus. Les modèles choisis sont les System Dynamics qui permettent la modélisation et la simulation des interactions entre les variables d’un système complexe. Cet outil d’aide à la décision permet d’éprouver les propositions de la thèse, au tour d’un exemple de régénération d’un D3E / This thesis is dedicated to the regeneration paradigm from the principles of sustainable development and circular economy. The intention is to limit the exhaustion of natural resources and to reduce waste production through exploiting “waste” deposits of technosphere. The notion of regeneration emerges from an analogy between the natural and technical sphere. It brings to light the concepts of “nutrients” and “decomposers”. The nutrient concept enables to revisit the end of life of domestic or industrial equipment. These equipment are seen as technical nutrients that can feed industrial sectors. The regenerators, called decomposers in nature, are intermediates processors to process “waste” in technical nutrients. Four regenerators have been identified. For each regenerator, product requirements are identified to ensure the regeneration of “waste” product. Additional requirements have been defined in the regeneration process to specify regeneration actions. These two types of requirements must be maintained throughout the product lifecycle. Maintenance process has been identified as fundamental industrial process to monitor and maintain over time the regeneration capability of a product. When regenerators implement a regeneration strategy, it is necessary to assess its feasibility. That is why we proposed a decision- making tool by modeling the product’s behavior during its lifecycle and the regenerator’s behavior, and the effect of the requirements on the product and process. The selected models are System Dynamics. These models allow the modeling and simulation of interactions between the variables of a complex system. The decision-making tool allow test the proposals of this thesis through a regeneration example of an electronic waste

Made available in DSpace on 2016-06-02T19:51:59Z (GMT). No. of bitstreams: 1 DissEJF.pdf: 2383698 bytes, checksum: f6fd745457de5bfdeefafca95cb3a484 (MD5) Previous issue date: 2004-12-13 / Universidade Federal de Minas Gerais / The family farmers play an important role in the Brazilian agricultural production. However, even though they occupy a prominent position in the agricultural production in Brazil, there are not management techniques specifically suitable to family farmers. Focusing on commercialization and vertical coordination, this dissertation has as main objective the development of management prescriptions related to procurement and marketing activities undertaken by family farmers. Computational simulation, based on System Dynamics methodology, was the main instrument to support procurement and marketing decisions. Interviews with thirty three vegetables family farmers and five of their main suppliers, all located in the region of São Carlos SP, provided the real data for the design of the computational model. The empirical research revealed that family farmers do not plan procurement and marketing appropriately, although they manage to compete with non-family production. The use of governance structures based on trust seems to be the main cause of their survival and success. The simulation based on System Dynamics helped the design of models that represent and help the decision making related the procurement and marketing by family farmers. / A agricultura familiar desempenha um papel importante na produção agropecuária brasileira. No entanto, mesmo ocupando uma posição de destaque na produção agrícola do país, o agricultor familiar não desfruta de ferramentas de gestão adaptadas as suas particularidades, as quais poderiam contribuir para aumentar a eficiência da atividade agrícola. Interessado na gestão da comercialização, este trabalho tem como principal objetivo desenvolver uma ferramenta de gestão capaz de auxiliar o produtor familiar a tomar decisão relacionadas a compra de insumos e venda de produtos. A metodologia de pesquisa adotada foi a simulação computacional, baseada na metodologia de System Dynamics, sendo que o procedimento adotado para a coleta dos dados foi o estudo de caso. Na investigação empírica foram entrevistados trinta e três produtores familiares de hortaliças e cinco de seus principais fornecedores, todos localizados no município de São Carlos SP. Constatou-se que os produtores familiares não planejam adequadamente a compra de insumos e a venda de seus produtos, no entanto, mesmo utilizando práticas gerencias inadequadas eles conseguem sobreviver na atividade, graças, sobretudo, a estrutura de governança baseada em relações de confiança utilizada para coordenar suas transações com fornecedores e clientes. A simulação baseada na metodologia de System Dynamics se mostrou eficiente na construção de modelos que representam e ajudam a resolver as situações-problema relacionadas a atividade agrícola familiar.

La transition énergétique, en partie caractérisée par le déploiement massif des énergies renouvelables, a relancé un débat de longue date sur les architectures de marché fournissant les meilleures incitations aux investissements dans les marchés libéralisés de l’électricité. Ces incitations sont essentielles pour garantir la sécurité d’approvisionnement à long terme. Pour choisir l’architecture de marché adéquate, les décideurs publics doivent évaluer et comparer les performances économiques des solutions disponibles. La présente thèse complète la littérature sur les incitations aux investissements et la sécurité d’approvisionnement en étudiant trois aspects importants : (i) le comportement des marchés de l'électricité en présence d’acteurs averses au risque, (ii) la compatibilité entre les incitations des acteurs à mettre leurs actifs sous cocon et les objectifs de sécurité d’approvisionnement et (iii) les performances économiques de différentes architectures de marché dans un contexte de forte pénétration des énergies renouvelables. Pour ce faire, une modélisation de type System Dynamics est utilisée pour représenter les dynamiques de long terme résultant des décisions des acteurs dans un marché libéralisé. La thèse est organisée en trois chapitres correspondant à chacun des points mentionnés ci-dessus. Les principaux résultats sont les suivants : Premièrement, les mécanismes de capacité sont nécessaires pour faire face aux effets néfastes de l’aversion au risque des investisseurs. Ce phénomène affecte de manière significative les marchés de l’énergie de type energy-only, qui subissent alors une baisse des investissements et des pénuries plus importantes. Les marchés de capacité résistent mieux à l’aversion au risque des investisseurs. Cependant, cette résilience dépend du plafond des prix dans les enchères de capacité. Pour qu'une telle architecture de marché donne des résultats satisfaisants en termes de sécurité d’approvisionnement, ce plafond de prix doit tenir compte du risque d'investissement supporté par les acteurs. Deuxièmement, si les acteurs du marché en ont la possibilité, leurs décisions de mettre leurs actifs sous cocon peuvent modifier les dynamiques d'investissement et de fermeture à long terme. En outre, dans un monde caractérisé par des actifs indivisibles, cette possibilité augmente le niveau de coordination nécessaire pour assurer la sécurité d’approvisionnement. Cela est particulièrement vrai pour les marchés de type energy-only, dans lesquels la mise sous cocon augmente le niveau des pénuries, au point de contrebalancer les économies de coûts qu’elle génère. En revanche, les marchés de capacité peuvent fournir la coordination nécessaire pour assurer la sécurité d’approvisionnement même lorsque les acteurs ont la possibilité de mettre leurs actifs sous cocon. Troisièmement, parmi les architectures de marché proposées dans la littérature, les marchés de capacité apparaissent comme la meilleure solution du point de vue du surplus social. Néanmoins, du point de vue des investisseurs, et dans certaines conditions liées à une forte pénétration des énergies renouvelables, les marchés de capacité avec des contrats annuels ne suppriment pas entièrement le problème dit de "missing money". Les résultats indiquent que l'attribution de contrats de capacité pluriannuels atténue le problème. / The ongoing energy transition, partly characterized by the massive deployment of renewables, has reignited a long-lasting debate on the best market design options to provide adequate investment incentives and ensure capacity adequacy in liberalised electricity markets. To choose the appropriate market design, policymakers need to assess and compare the economic performances of available solutions in terms of effectiveness and cost-efficiency. This dissertation complements the existing literature on market design for long-term capacity adequacy by focusing on three research topics: (i) understanding how electricity markets perform under different assumptions regarding investors’ risk preferences, (ii) analysing the compatibility of private agents’ incentives to mothball capacity resources with security of supply objectives and (iii) assessing the economic performance of different market designs in a context of a high penetration of renewables. To this end, the System Dynamics modelling framework is applied to represent long-term dynamics resulting from private agents’ decisions in liberalised electricity markets. The dissertation is organised in three chapters corresponding to each of the topics mentioned above. The main results are outlined below. Firstly, capacity remuneration mechanisms are necessary to deal with the detrimental effects of investors’ risk aversion. Energy-only markets are significantly affected by this phenomenon as they experience reduced investment incentives and higher levels of shortages. Capacity markets are more resilient to private investors’ risk aversion. However, this resilience depends on the level of the price cap in the capacity auctions. For such a market design to provide satisfactory outcomes in terms of capacity adequacy, this price cap should account for the investment risk faced by market participants. Secondly, when market participants have the possibility to mothball their capacity resources, these mothballing decisions can potentially modify investment and shutdown dynamics in the long run. Furthermore, in a world with capacity lumpiness (i.e. indivisibilities), mothballing increases the level of coordination needed to ensure capacity adequacy. This is especially true in energy-only markets, where mothballing increases the level of shortages to an extent that seems to overweigh the cost savings it generates at system level. Capacity markets can provide the required coordination to ensure capacity adequacy in a world with mothballing. Thirdly, among proposed market designs in the literature, capacity markets appear as the preferable solution to ensure capacity adequacy from a social welfare point of view. Nevertheless, from a private investor’s perspective and under certain conditions related to high penetration of renewables, capacity markets with annual contracts do not entirely remove the so-called “missing money” problem. The results indicate that granting multiannual capacity contracts alleviates the problem.

Les marchés électriques libéralisés sont supposés assurer la coordination de long terme des investissements afin de garantir sécurité d’approvisionnement, viabilité et compétitivité. Dans le modèle de référence energy-only, la formation des prix par alignement sur le coût variable de l’équipement marginal sur les marchés horaires successifs fournit un signal prix pour les investisseurs. Cependant, en pratique, ce modèle est remis en question quant à sa capacité à déclencher des investissements dans les technologies bas-carbone et en particulier les énergies renouvelables (EnR) et quant à sa capacité à garantir la sécurité d’approvisionnement. Cette thèse cherche d’abord à caractériser ces deux défaillances de marché puis s’intéresse à différentes solutions pour faire face à chacune d’entre elles. Pour cela, la réflexion s’appuie sur un modèle en System Dynamics développé afin de simuler les investissements dans les marchés électriques.D’une part, les résultats montrent que le remplacement des mécanismes de support hors marché par des investissements par le marché avec l’aide d’un prix du carbone apparait comme une solution pour déclencher le développement des EnR à condition d'un engagement politique fort en faveur d’un prix du carbone élevé. D’autre part, il apparait aussi que le marché energy-only avec des prix plafonnés ne parvient pas à assurer l’adéquation de capacité. L’ajout d’un marché de capacité ou la suppression du plafond de prix permettent une amélioration en termes de nombre d’heure de délestage et de bien-être collectif. De plus, le marché de capacité apparaît comme le meilleur choix pour le régulateur parmi les architectures de marché considérées. / In liberalised electricity systems, power markets are expected to ensure the long-term coordination of investments in order to guarantee security of supply, sustainability and competitiveness. In the reference energy-only market, it relies on the ability of power markets — where the hourly price is aligned with the marginal cost of the system — to provide an adequate price-signal for investors. However, in practice, questions have been raised about its ability to trigger investments in low-carbon technologies including in particular Renewable Energy Sources of Electricity (RES-E), and its ability to ensure capacity adequacy. After a characterisation of these market failures, this dissertation tackles the two research topics within a methodological framework based on a System Dynamics model developed to simulate private investment decisions in power markets.First, the results show that substituting out-of-market support mechanisms for RES-E by market-based investments helped by the sole implementation of a carbon price appears as a feasible solution to trigger RES-E development providing that there is a political commitment on a high carbon price. Second, it also appears that the energy-only market with price cap is ineffective to ensure capacity adequacy. Adding a capacity market or removing the price cap both bring benefits in terms of loss of load expectation and social welfare. Moreover, the capacity market is identified as the best option for regulators among the considered market designs.

In Indonesia, the various mining commodities and the amount of resources and reserves are promising, as evidence there are numerous large-scale mining companies and small-scale mines in operation. In 2014 there were 41 companies that held the CoW (mineral contract of work) and 13 companies active in production; and 76 CCoW (coal contract of work) holders, and 57 companies active in production. As well as this, there are more than a thousand small-scale mining companies active for mining commodities. However, mining commodities provide a resource that is not renewable. This will potentially lead to prolonged problems when mining companies do not adhere to good mining practices, particularly in the closing stages of the mine. Mine closure is the final stage in the process of mining activity. In certain circumstances, closure activities can take a long time and of course can have huge costs. In fact, at this stage, the company is no longer making profit, only incurring costs for the project closure. To prevent problems that may arise after the mine is closed, such as abandoned post-mining land, and the bankruptcy of the company at the end of mining operations, etc., then through specific rules, ie rules of the Minister of Energy and Mineral Resources No. 18 of 2008, the mining company in Indonesia must provide a certain amount of money as a financial guarantee to finance the planned closure project; it must be approved by the government before entering this phase. However, problems are encountered in practice. The government may become overloaded because they have to quickly make a decision on the closure plan submitted by the company. So a tool is needed that can be used to assess the feasibility as soon as the mine closure plan is proposed by a company, these tools can provide an overview and a variety of options for decision making. In this dissertation methodology was developed to create a systems dynamic model of mine closure. The model developed can be applied to a variety of mining methods and for various mining commodities. The model can be used to determine the closure costs, to choose the closure project-financing scenario, and up to micro and macro economic analysis of mining activities in the region. In the case studies conducted in this dissertation, the best scenario of the mine closure planning is to include the everlasting fund in the form of time deposits, and convert the post-mining land for agriculture. The amount of deposit money is about USD 358,986,500 should be spare at the end of mine production, and the total of mine closure cost to be approximately USD 440,757,384. Agriculture, the economic sector as a substitute for the mining sector, the added value to the GRDP (Gross Regional Domestic Product) is about 0.25 % / a for the province, and 1.68 % for the regency, but the contribution of the mining sector to GRDP was 30% / a at province scale, and 90% / a at regency scale. So that the substitution value is less significant to GRDP growth. However, this scenario is the best scenario among others, due to consideration is the certainty of ecological and economic sustainability. it is the best goal of corporate social responsibility to the environment in the post- mining land.

Extensive digitization is currently underway in the railway sector, which has resulted in several benefits and improvements, but also challenges. The increased use of digital technologies increases the risks of vulnerabilities and susceptibility to cyberattacks. The effects of a cyber attack can have significant consequences on operations such as financial losses and damaged reputations, or in the worst-case scenario, devastating consequences where the lives of passengers are endangered. With the ongoing digitalization of the railways and the growing concern for cybersecurity, stakeholders in the sector have identified the need to systematically understand the risks of digitization related to cybersecurity and safety. Therefore, this study aims to identify and communicate these risks using system dynamics modeling. This study evaluated how actors in the railway sector reason about risks in the railway, how safety and cybersecurity are related, and new risks associated with digitalization and cybersecurity that have not been mentioned in the literature before. A qualitative study was conducted to answer the research question. Ten actors from different parts of the railway value chain were interviewed, and secondary data was collected from articles and reports within the area of cybersecurity and the railways. The results revealed a connection between cybersecurity and safety which could be seen through the chain of consequences that can arise from a cyberattack and in the event of loss of data availability and integrity. Based on this, core elements of the system and the relationships between them could be identified, from which the causal loop diagram (CLD) was constructed. New risks that were identified were the safety culture that permeates the railway industry, unclear areas of responsibility that are a result of deregulation in the Swedish railway sector, and competitiveness. Insights from the system dynamic model identified a reinforcing loop telling a causal story that shows that low cybersecurity priorities could lead to decreased safety on the railway. This further demonstrates the usefulness of identifying and communicating risks using system dynamics modeling. / En omfattande digitalisering pågår just nu inom järnvägssektorn vilket dels har resulterat i en mängd fördelar och förbättringar, men också utmaningar. Den ökade användningen av digitala teknologier ökar risker för sårbarheter samt mottagligheten av cyberattacker. Effekterna av en cyberattack kan ha betydande konsekvenser på verksamheten så som ekonomiska förluster och skadat rykte, eller också i värsta fall förödande konsekvenser där passagerarnas liv sätts i fara. I och med den pågående digitaliseringen av järnvägen och den ökade oron för cybersäkerhet har intressenter inom sektorn identifierat behovet av att på ett systematisk sätt förstå riskerna med digitalisering relaterade till cybersäkerhet och säkerhet (safety). Denna studie syftar därför till att identifiera och kommunicera dessa risker genom att använda systemdynamisk modellering. Studien utvärderade hur aktörer i järnvägens värdekedja resonerade kring risker i järnvägen, hur säkerhet och cybersäkerhet var relaterat, samt vad det finns för nya risker relaterade till digitaliseringen och cybersäkerhet som inte nämnts i litteraturen tidigare. En kvalitativ studie genomfördes för att svara på frågeställningen. Tio aktörer från olika delar av järnvägssektorns värdekedja intervjuades, och sekundärdata samlades in från artiklar och rapporter inom cybersäkerhet och järnvägen. Resultaten visade att det finns en koppling mellan cybersäkerhet och säkerhet (safety) som syns i den kedja av konsekvenser som kan uppstå från en cyberattack vid förlust av datas tillgänglighet och integritet. Utifrån detta kunde nyckelelement i systemet samt relationerna mellan dessa identifieras, och baserat på detta konstruerades vidare ett causal loop diagram (CLD). Nya risker som identifierades var säkerhetskulturen som genomsyrar järnvägsbranschen, oklara ansvarsområden som är ett resultat av den svenska järnvägens avreglering, samt konkurrenskraft. Insikter från den systemdynamiska modellen identifierade en förstärkande loop som berättar en orsakshistoria som visar att låg prioritering av cybersäkerhet kan leda till minskad säkerhet på järnvägen. Vidare demonstrerar detta nyttan av att identifiera och kommunicera risker med hjälp av systemdynamsik modellering.

Published Article / South African cities are in the process of transition in the changing scenario and need a change in the planning perspective for their sustainable development. The concept of smart city offers opportunities for such development to many middle sized cities of South Africa. Therefore, in this paper conceptual modelling for development of smart cities in South Africa is attempted based on systems concept. The conceptual models are built by using the principles of system dynamics methodology and based on causal feedback relationships among the various factors under different smart characteristics of a city such as, smart economy, smart people, smart governance, smart mobility, smart environment and smart living. The causal feedback loops and interrelationship among various parameters illustrate the dynamicity and influence of parameters on one another, which would able to assist in evolving plausible policy interventions for developing smart cities in South Africa. It is concluded that the modelling approaches presented here could guide the policy makers and city planners to evolve robust and responsive policy interventions for developing smart cities in the changing scenario.

Published Article / The emergence of Information Technology (IT) is increasingly influencing the socio-economic and physical landscape of cities. It has also resulted in development of predominantly IT based industrial cities. These cities have the opportunities and challenges with respect to the development of their socioeconomic, infrastructural and environmental conditions because of the influence of the IT based industrial activities. This article therefore pertains to the analysis of the perspective impacts of IT industry and allied activities on the development of an emerging IT industrial activity based city. For this purpose, Pune, an emerging IT city in India was considered as a case study. Survey research methodology and a system dynamics modelling approach were employed to measure the influential socio-economic, infrastructural and environmental parameters of the city by considering the city as a system. This research shows that the location of IT industry and associated functions contribute significantly towards the socio-economic development of a city in terms of IT industry export, State Gross Domestic Product (SGDP), per capita SGDP, employment generation, to name some relevant aspects. However, there would be a reduction in satisfaction level of the infrastructure and an increase in environmental stress in the system, which needs strategic attention. Further, the model results and scenarios can facilitate evolving of feasible policy and strategic guidelines for the wholesome development of such cities.

The transportation system is vital to the nation’s economic growth and stability, as it provides mobility for commuters while supporting the United States’ ability to compete in an increasingly competitive global economy. State Transportation Agencies across the country continue to face many challenges to repair and enhance highway infrastructure to meet the rapid increasing transportation needs. One of these challenges is maintaining an adequate and efficient agency staff. In order to effectively plan for future staffing levels, State Transportation Agencies need a method for forecasting long term staffing requirements. However, current methods in use cannot function without well-defined projects and therefore making long term forecasts is difficult. This dissertation seeks to develop a dynamic model which captures the feedback mechanisms within the system that determines highway staffing requirements. The system dynamics modeling methodology was used to build the forecasting model. The formal model was based on dynamic hypotheses derived from literature review and interviews with transportation experts. Both qualitative and quantitative data from literature, federal and state database were used to support the values and equations in the model. The model integrates State Transportation Agencies’ strategic plans, funding situations and workforce management strategies while determining future workforce requirements, and will hopefully fill the absence of long-term staffing level forecasting tools at State Transportation Agencies. By performing sensitivity simulations and statistical screening on possible drivers of the system behavior, the dynamic impacts of desired highway pavement performance level, availability of road fund and bridge fund on the required numbers of Engineers and Technicians throughout a 25-year simulation period were closely examined. Staffing strategies such as recruiting options (in-house vs. consultants) and hiring levels (entry level vs. senior level) were tested. Finally the model was calibrated using input data specific to Kentucky to simulate an expected retirement wave and search for solutions to address temporary staffing shortage.

Healthcare problems are complex; they exhibit both detail and dynamic complexity. It has been argued that Discrete Event Simulation (DES), with its ability to capture detail, is ideal for problems exhibiting this type of complexity. On the other hand, System Dynamics (SD) with its focus on feedback and nonlinear relationships lends itself naturally to comprehend dynamic complexity. Although these modelling paradigms provide valuable insights, neither of them are proficient in capturing both detail and dynamic complexity to the same extent. It has been argued in literature that a hybrid approach, wherein SD and DES are integrated symbiotically, will provide more realistic picture of complex systems with fewer assumptions and less complexity. In spite of wide recognition of healthcare as a complex multi- dimensional system, there has not been any reported study which utilises hybrid simulation. This could be attributed to the fact that due to fundamental differences, the mixing of methodologies is quite challenging. In order to overcome these challenges a generic theoretical framework for hybrid simulation is required. However, there is presently no such generic framework which provides guidance about integration of SD and DES to form hybrid models. This research has attempted to provide such a framework for hybrid simulation which can be utilised in healthcare domain. On the basis of knowledge induced from literature, three requirements for the generic framework have been established. It is argued that the framework for hybrid simulation should be able to provide answers to Why (why hybrid simulation is required), What (what information is exchanged between SD and DES models) and How (how SD and DES models are going to interact with each other over the time to exchange information) within the context of implementation of hybrid simulation to different problem scenarios. In order to meet these requirements, a three-phase generic framework for hybrid simulation has been proposed. Each phase of the framework is mapped to an established requirement and provides guidelines for addressing that requirement. The proposed framework is then evaluated theoretically based on its ability to meet these requirements by using multiple cases, and accordingly modified. It is further evaluated empirically with a single case study comprising of Accident and Emergency department of a London district general hospital. The purpose of this empirical evaluation is to identify the limitations of the framework with regard to the implementation of hybrid models. It is realised during implementation that the modified framework has certain limitations pertaining to the exchange of information between SD and DES models. These limitations are reflected upon and addressed in the final framework. The main contribution of this thesis is the generic framework for hybrid simulation which has been applied within healthcare context. Through an extensive review of existing literature in hybrid simulation, the thesis has also contributed to knowledge in multi-method approaches. A further contribution is that this research has attempted to quantify the impact of intangible benefits of information systems into tangible business process improvements. It is expected that this work will encourage those engaged in simulation (e.g., researchers, practitioners, decision makers) to realise the potential of cross-fertilisation of the two simulation paradigms.