O presente trabalho aborda o problema da variabilidade da prática médica, entendida como as variações sistemáticas na utilização de um procedimento médico ou cirúrgico após terem sido descartadas como causas as diferenças entre as populações e os pacientes. Teoricamente se espera que o comportamento dos médicos seja uniforme, isto é, que frente a uma população fixa, a taxa de encaminhamento dos médicos a procedimentos diagnósticos ou tratamentos hospitalares seja muito parecida, mas na realidade a taxa de encaminhamento segue uma distribuição que da conta dá variabilidade na prática médica. A partir do banco de dados de uma seguradora de saúde colombiana, foi realizada uma vasta análise estatística que permitiu encontrar variáveis importantes para a abordagem do problema. Dentre as variáveis estudadas, mereceram destaque a distribuição de pacientes atendidos pelos médicos (concentração) e a taxa de encaminhamento para cirurgia. O trabalho procura, a partir de simulação computacional, utilizando modelagem baseada em agentes, reproduzir as funções de distribuição empíricas referentes a concentração e a taxa de encaminhamento para procedimentos cirúrgicos. O modelo está baseado na hipótese econômica da renda alvo, teoria da sociologia dos grupos e em dados empíricos. / This study addresses the problem of medical practice variation (MPV), which is the presence of variation in the use of a medical procedure that is not explained by environmental, demographic or epidemiological differences. Theoretically, it is expected that the behavior of physicians were uniform for a fixed population, the rate of remission for diagnostic procedures or hospital treatment must be very similar, but in practice the remission rate follows a distribution that account the variability in medical practice. We used the data base of a Colombian health insurance company. Statistical analysis found important variables to approach the problem as: distribution of patients seen by the physician (concentration) and the rate of referral for surgery.

The aim of this diplomma thesis is to build a platform of the phenomenon of emergence in complex information systems. To our best knowledge, there has not been provided any similar concept in either internetional or domestic academic literature. The necessity to create a concept of the phenomenon of emergence in the enviroment of information systems stems from the observation of the fragmented knowledge about the emergence concept in the pool of scientific papers where the link between emergence and information systems is missing. As a result, the platform created in this work is the reaction to the lack of the above mentioned link, while the ambition is to provide a cornerstone for potential emergence's utilization in information systems. In this work, we provide a construct that describes and analyzes the characteristics, technics and methodologies in connection with the phenomenon of emergence, placing a great deal on the specifics of the emergence in complex information sytems. Special attention is paid to eNetworks that we consider to be the best enviroment for examining the characteristics of emergent behavior in regards to the concept of complexity. This enviroment shows suitable conditions for the analysis of information spreading and dynamic interactions, which is primarily connected with generating of emergent characteristic. In order to understand the causality of specific emergence's demonstrations, we take a closer look at two approaches: Holonistic multi-agemt systems and iterative simulation process.

O presente trabalho aborda o problema da variabilidade da prática médica, entendida como as variações sistemáticas na utilização de um procedimento médico ou cirúrgico após terem sido descartadas como causas as diferenças entre as populações e os pacientes. Teoricamente se espera que o comportamento dos médicos seja uniforme, isto é, que frente a uma população fixa, a taxa de encaminhamento dos médicos a procedimentos diagnósticos ou tratamentos hospitalares seja muito parecida, mas na realidade a taxa de encaminhamento segue uma distribuição que da conta dá variabilidade na prática médica. A partir do banco de dados de uma seguradora de saúde colombiana, foi realizada uma vasta análise estatística que permitiu encontrar variáveis importantes para a abordagem do problema. Dentre as variáveis estudadas, mereceram destaque a distribuição de pacientes atendidos pelos médicos (concentração) e a taxa de encaminhamento para cirurgia. O trabalho procura, a partir de simulação computacional, utilizando modelagem baseada em agentes, reproduzir as funções de distribuição empíricas referentes a concentração e a taxa de encaminhamento para procedimentos cirúrgicos. O modelo está baseado na hipótese econômica da renda alvo, teoria da sociologia dos grupos e em dados empíricos. / This study addresses the problem of medical practice variation (MPV), which is the presence of variation in the use of a medical procedure that is not explained by environmental, demographic or epidemiological differences. Theoretically, it is expected that the behavior of physicians were uniform for a fixed population, the rate of remission for diagnostic procedures or hospital treatment must be very similar, but in practice the remission rate follows a distribution that account the variability in medical practice. We used the data base of a Colombian health insurance company. Statistical analysis found important variables to approach the problem as: distribution of patients seen by the physician (concentration) and the rate of referral for surgery.

In this research, several improvements to the European Union Emissions Trading System (EU ETS) were analysed. The EU ETS is a market for emission allowances and the European Union's main instrument for reducing greenhouse gas emissions (of which CO2 is the main component). However, the CO2 allowance price in this market has been highly volatile and generally too low to stimulate significant long-term reductions in CO2 emissions. National and system-wide price floors and ceilings were investigated, prompted by the UK’s implementation of a CO2 price floor through a supplementary CO2 tax. The effects of the "backloading" of CO2 allowances and the proposed Market Stability Reserve were also investigated. While the latter measures may increase dynamic efficiency, this research showed that a well-designed price corridor is even more efficient, while still achieving the long-term abatement targets and stabilising prices. Furthermore, different methods for adjusting the CO2 emissions cap in response to changes in renewable energy policies were investigated. Finally, the impact of investors' risk aversion on the functioning of the CO2 market was evaluated. The analyses were conducted with the use of EMLab-Generation, an agent-based model that simulates two interconnected electricity markets with a joint CO2 emissions trading system. In this model, the companies have limited knowledge about the future, which makes it possible to investigate the impact of public policy instruments on long-term investment dynamics. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively.</p><p>copyright notice:(c) 2015 Richstein, J.C. · Creative Commons Attribution-Non- Commercial-NoDerivatives 4.0 International License</p><p>QC 20151109</p>

Agricultural adaptation to climate change is often simulated by changes in land use over time. Land use is commonly optimised in economic models, which rests on the neoclassical economic assumption of rational choice among farmers. A wealth of experimental and empirical evidence demonstrates that rational choice can be a poor approximation of human decision making. Models simulating adaptation by optimising producers’ behaviour are in effect simulating adaptive potential. Much evidence demonstrates that adaptive potential does not necessarily translate into adaptation. This investigation focuses on the ways by which farmers’ real-world adaptive behaviours depart from those assumed by the dominant economic models of agricultural responses to climate change. These departures are characterised as adaptation constraints, and they are assessed through an empirical case study of adaptive behaviours in the Hikurangi catchment, New Zealand. Data are collected using a mixed methodology comprising an extensive survey of rural decision making, to which this study contributes, and a suite of semi-structured interviews. The interviews give an understanding of the origins and processes of adaptation constraints, while the surveys provide information about the extent to which they impact adaptive propensity. These adaptation constraints are then formalised as mathematical rules and written into an existing agent-based model of land use change, which is substantially modified for the purposes of this study. Different combinations of constraints are then tested in order to produce estimates of their economic impacts. The constraints on adaptation are found to significantly reduce profits relative to a specification that assumes rational choice among farmers. This is understood to be the first empirically derived estimate of the extent of the adaptation deficit. The size of the deficit identified in this study implies that current economic models are likely to significantly underestimate the costs of adaptation to climate change, the benefits of climate change mitigation, and the residual loss and damage climate change will cause.

The requirement for affordable, secure and sustainable energy production is a pressing global challenge and the production of electricity with low carbon emissions is crucial. This usually entails large quantities of renewable energy generation, which is intermittent and often highly distributed throughout the electricity supply system. One of the proposed schemes to manage such generation is the smart grid, the transition to which forms the context for this research. The aim is to investigate the effect of certain psychological and social influences on the adoption of technology necessary to enable smart grids, in order to understand the implications for effective energy policy. In particular, the case of photovoltaic (PV) system adoption in the UK is studied. Empirical data detailing PV installations registered for the Feed in Tariff is analysed in order to understand rates of adoption and how they vary across both time and space. This analysis is combined with a review of policy intervention and literature from psychology to understand drivers for adoption among householders. The results from this study are then used to inform the design of an Agent Based Model of technology adoption within the smart grid context. The decision making of householders is modelled using an algorithm based on Social Cognitive Theory. The model is used to simulate different conditions and generate adoption scenarios in order to understand the potential effects of different parameters on adoption rates. In order to combine the analysis resulting from these methods, the multi-level perspective on transition in socio-technical systems is used to understand how a transition to a smart grid could be described and how adoption of PV in the UK under the Feed in Tariff incentive fits into such a transition. The results show that whilst economic incentive policies have had success in some areas adoption is also dependent on many non-financial parameters. Simulations show that the observability of adoption and the perceived inconvenience or urgency of adoption can have dramatic effects on rates of adoption, in some cases outweighing the rational economic effects of financial incentives. The implication for smart grid related policy is that non-financial factors should be taken into account as well as the more typical financial considerations in efforts to encourage adoption of necessary enabling technology by householders. The models developed could be used in further work to examine in detail adoption of other technologies such as smart home energy management systems and the interaction between adoption rates of multiple smart technologies.

L’objectif des travaux présentés dans cette thèse est d’étudier la diffusion de l’information dans les marchés financiers. Considérant comme établi que les individus sont hétérogènes et à rationalité limitée, nous avons fondé nos travaux sur une catégorie de modèles computationnels dans le but de simuler les actions et les interactions des agents autonomes. Cette catégorie est communément nommée modélisation agent (ABM).Plus concrètement, cette recherche se concentre sur le rôle de l’hétérogénéité des agents dans la diffusion et l’utilisation de l’information. À cet effet, nous avons développé deux structures de marché, qui diffèrent par leur transparence. Dans les chapitres 1 et 2, nous introduisons un marché centralisé, où une partie du carnet d’ordre est accessible (information publique). Dans le chapitre 3, nous développons un marché de gré à gré dans lequel les agents négocient et échangent avec leurs relations. / The piece of work’s aim is to understand information diffusion in financial markets. Starting from the empirical evidences that agents are heterogeneous and bounded rational, we based our investigations on a class of computational models for simulating the actions and interactions of autonomous agents: the agent - based model (ABM). More precisely, this research focuses on the impacts of agents heterogeneity in diffusion and use of information. For this purpose, we developed two market structures, in which the market transparency varies. In the chapters 1 and 2, we introduce a centralised market, where a part of the order-book is available as a public information. In the chapter 3, we build an Over-The-Counter market, where agents bargains with their trading contacts.

A question concerning not only modellers but also practitioners is: Under what circumstances can mutual cooperation be established and maintained by a group of people facing a common pool dilemma" A step before this question of institutional influences there is need for a different way of modelling human behaviour that does not draw on the rational actor paradigm, because this kind of modelling needs to be able to integrate various deviations from this theory shown in economic experiments. We have chosen a new approach based on observations in form of laboratory and field observations of actual human behaviour. We model human decision making as using an adaptive toolbox following the notion of Gigerenzer. Humans draw on a number of simple heuristics that are meaningful in a certain situation but may be useless in another. This is incorporated into our agent-based model by having agents perceive their environment, draw on a pool of heuristics to choose an appropriate one and use that heuristic.Behavioural differences can be incorporated in two ways. First, each agent has a number of attributes that differ in values, for example there are more and less cooperative agents. The second behavioural difference lies in the way, in which heuristics are chosen. With this modelling approach we contribute to a new way of modelling human behaviour, which is simple enough to be included into morecomplex models while at the same time realistic enough to cover actual decision making processes of humans. Modellers should be able to use this approach without a need to get deep into psychological, sociological or economic theory. Stakeholders in social dilemmas, who may be confronted with such a model should understand, why an agent decides in the way it does.

The uptake of residential photovoltaic systems is essential for energy system transformation towards carbon neutrality and decentralization. However, despite numerous campaigns to incentivize their uptake, adoption by residential homeowners is lacking behind. While countless drivers and barriers have been identified, the decision process is not fully understood. To address this gap, we developed an agent-based residential rooftop photovoltaic adoption model called PVact. Our model analyzes the interactions of potential household adopters based on their utility functions and social network, with a focus on the role of monetary evaluation and social pressure in adoption behavior. In this paper, we aim to assess the influence of monetary evaluation and social pressure in an abstract case study based on real-world data from the municipality of Leipzig, Germany. We consider stochastic dynamics through scenario analysis to investigate the influence of these factors on adoption behavior. Our results show that monetary evaluation and social pressure have a significant impact on adoption behavior. Specifically, we find shifting adoption patterns with an increased requirement for monetary returns and higher level of normative pressure required for households to act. Higher resistance against these pressure shows more stochastic variations,

Goal and incentive alignment are a means of establishing collaborative behavior in supply chains. Essay 1 examines goal and incentive alignment at the strategic level in the purchasing process. It employs survey research in conjunction with structural equation modelling to examine the source selection strategy as a means of aligning the goals of the offeror with those of the buyer. Essay 2 examines goal and incentive alignment at the tactical level. It uses discrete event simulation to explore how the pursuit of localized profit objectives affects the global profitability of a supply chain. Lastly, Essay 3 examines goal and incentive alignment at the operational level. By employing a hybrid simulation approach to model a complex product refurbishment process, this research demonstrates that evaluating subprocesses based solely on their throughput does not equate to greater cost savings for the company at the focal point of this case study. These essays contribute to the body of knowledge in several ways. To the best of the author's knowledge, Essay 1 demonstrates the first empirical linkage, in the realm of public procurement, between the fear of a bid protest and the appropriateness of the sourcing strategy. Similarly, Essay 2 represents the first adaptation of Sterman's Beer Game to a format in which the value of products increases while they travel downstream. It also stands as the first research to quantitively explore the value of supply chain cooperation as a function of relative position in a supply chain. Lastly, the methodology employed in Essay 3 answers calls for research as they pertain to the need for case studies from industry, as well as the need to preserve the ‘real-world' context in complex, industry-based problems.