Made available in DSpace on 2016-08-17T14:53:04Z (GMT). No. of bitstreams: 1 Eduardo Werley Silva dos Angelos.pdf: 3115744 bytes, checksum: 6426e6a53fa69a9616988e00882cb314 (MD5) Previous issue date: 2009-08-07 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work proposes a computational technique for classification of electricity consumption profiles. The approach is based on the assumption that it s possible to find out groups of consumers with similar patterns of energy use. So, given the found groups, which can be also viewed as a normal consumption profile, ones can associate a high chance of fraud or abnormality to that consumers lying more apart from the groups. The methodology comprises two steps. A fuzzy clustering c-means-based is done in order to search for consumers with similar consumption profiles, in the first one. Afterwards, a fuzzy classification is performed using a fuzzy membership matrix and the Euclidian distance to the cluster centers. Then, the distance measures are normalized and ordered, yielding an unitary index score, where the possible fraudulent or abnormal consumers are those with the higher scores. The approach was tested and validated with real data base, showing good performance in both fraud and metering defect detection tasks. / Este trabalho apresenta uma metodologia computacional para classificação de perfis anormais de consumo de energia elétrica. A abordagem parte da premissa que um dado cliente deve permanecer o mais próximo possível de seu padrão de consumo histórico, sendo que os desvios do padrão registrado representam possíveis fraudes de energia ou irregularidades de medição. A parte inicial da metodologia busca de consumidores com perfis de consumo semelhantes é efetuada por meio da técnica computacional de clusterização fuzzy. Já a tarefa de mensurar o desvio do padrão histórico é realizada por meio de uma metodologia de classificação nebulosa, baseada na matriz de partição fuzzy e distância dos elementos aos centros dos agrupamentos. Por fim, as distâncias para os grupos são normalizadas, gerando um índice no intervalo unitário, sendo que os elementos de maior chance de estarem irregular são aqueles com índices mais próximos de um. A metodologia foi validada com uma base de dados de uma concessionária local. Os resultados alcançados foram satisfatórios, sendo obtida adequada performance tanto no processo de detecção de fraudes quanto irregularidades na medição.

Submitted by audrey souza (audrey_ajs@yahoo.com.br) on 2012-06-26T20:41:54Z No. of bitstreams: 1 DISSERTAÇÃO-VERSÃO FINAL-SUBMISSÃO.pdf: 807877 bytes, checksum: 4644a892d7a17719575f32f1e5978822 (MD5) / Approved for entry into archive by ÁURA CORRÊA DA FONSECA CORRÊA DA FONSECA (aurea.fonseca@fgv.br) on 2012-06-28T12:20:46Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO-VERSÃO FINAL-SUBMISSÃO.pdf: 807877 bytes, checksum: 4644a892d7a17719575f32f1e5978822 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2012-06-29T17:33:43Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO-VERSÃO FINAL-SUBMISSÃO.pdf: 807877 bytes, checksum: 4644a892d7a17719575f32f1e5978822 (MD5) / Made available in DSpace on 2012-06-29T17:35:20Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO-VERSÃO FINAL-SUBMISSÃO.pdf: 807877 bytes, checksum: 4644a892d7a17719575f32f1e5978822 (MD5) Previous issue date: 2012-03-20 / The impacts of adopting International Accounting Standards (IFRSs) has been the subject of debate in the professional and academics media, however, little has been researched on the impact of adopting IFRSs in federal forensic expert. Therefore, the objective of this study is to capture and analyze the perception of the federal forensic expert on the impacts of the adoption of IFRSs in the investigative official activity held in accounting fraud. It was based on a quantitative and qualitative approach used to assess associations between perceptions, resorting to the chi-square test and content analysis, respectively. The results showed that most respondents agree partially or fully that the adoption of IFRS will facilitate the work of federal forensic expert, finding statistical association with the perception that fraud without financial engineering is easier to prove and with the perception that more space for technical judgments have positive impact on the activity of federal forensic expert. Other benefits mentioned were the increased comparability, reduction of complexity and professional development. However, it was verified the possibility of increased risks in the technical objections to expert reports, the risk of bias and the need for qualification, but without statistical association with the perception that IFRSs or otherwise facilitate the examination. No statistical differences were identified on the basis of perceived levels of knowledge of the precepts on IFRSs and the theoretical and practical knowledge of respondents. The study has limitations concerned primarily to generalization of the results, since the intended approach was qualitative and quantitative, and the number of answered questionnaires did not allow performing statistical tests with greater robustness. / Os impactos da adoção das Normas Internacionais de Contabilidade (IFRSs) tem sido objeto de debates nos meios profissionais e acadêmicos, entretanto, pouco tem sido pesquisado sobre as repercussões da adoção dos IFRSs na atividade pericial criminal. Portanto, o objetivo deste estudo é captar e analisar a percepção dos Peritos Criminais Federais sobre os impactos da adoção dos IFRSs na atividade de perícia criminal oficial realizada em fraudes contábeis. Lastreou-se numa abordagem quantitativa e qualitativa utilizada para verificar associações entre as percepções, recorrendo-se ao teste Qui-quadrado de Pearson e a análise de conteúdo, respectivamente. Os resultados evidenciaram que a maior parte dos respondentes concorda parcial ou totalmente que a adoção dos IFRSs facilitará o trabalho de perícia criminal federal, encontrando associação estatística com a percepção de que fraudes cometidas sem engenharia financeira são mais fáceis de comprovar e com a percepção que um maior espaço para julgamentos técnicos tem impacto positivo na atividade de perícia criminal. Outros benefícios apontados foram o aumento da comparabilidade, a diminuição da complexidade e a valorização profissional. Entretanto, constatou-se como riscos a possibilidade de aumento nas contestações técnicas aos laudos periciais, o risco de viés e a necessidade de qualificação, porém sem associação estatística com a percepção de que os IFRSs facilitarão ou não o trabalho pericial. Não foram identificadas diferenças estatísticas de percepção em função do nível de conhecimento dos preceitos sobre os IFRSs e dos conhecimentos teóricos e práticos dos pesquisados. O estudo apresenta limitações que dizem respeito principalmente à generalização dos resultados, uma vez que a abordagem pretendida foi qualitativa e quantitativa e o número de questionários respondidos não possibilitou realizar testes estatísticos com maior robustez.

La récurrence du déficit public en Guinée et la difficulté subséquente de financer les services publics, exigent que des ressources financières soient davantage identifiées pour y pallier. Parmi les moyens de résorption du déficit, l'impôt, du fait de sa faible participation budgétaire (17% contre 20% du PIB dans les pays de la sous-région Ouest-africaine) constitue une des recettes publiques dont le rendement doit être substantiellement amélioré. L'atteinte d'un tel objectif requiert d'abord que nous réformions la politique fiscale  : outre la mise en exergue des accords commerciaux dont les implications fiscales et douanières amenuisent les recettes budgétaires, et les dépenses fiscales consécutives aux politiques d'attraction des investissements étrangers, il importe de proposer des stratégies d'amélioration du rendement fiscal, lesquelles consistent à réformer d'une part la fiscalité intérieure et d'autre part, à renforcer la coopération fiscale internationale en vue de mieux lutter contre la fraude et l'évasion fiscales. Il importe ensuite que nous nous intéressions aux rapports entre l'administration des impôts et le contribuable. Il s'agit notamment d'identifier les raisons du manque de civisme du contribuable guinéen. Celles-ci se résument à une propension de l'administration financière publique, dotée d'importants pouvoirs, à renflouer les caisses publiques face à des contribuables qui ne bénéficient que de faibles garanties juridiques, et à une profonde méfiance de ces derniers quant à la bonne gestion de l'impôt acquitté, ce qui nécessite des mesures extra-fiscales garantissant l'efficacité et l'efficience des ressources publiques, donc fiscales. / The recurrence of the public deficit in Guinea and the subsequent difficulty of financing public services, requires that more financial resources are identified to address them. Among the means of reducing the deficit, tax, due to its low budget participation (17% against 20% of GDP in the countries of the West African sub-region) is a government revenue whose performance must be substantially improved.Achieving this goal requires first that we reform the tax policy : In addition to highlighting commercial agreements including tax and customs implications dwindling budget revenues, and tax expenditures resulting from the policy of attraction of foreign investments, it is important to improve the tax efficiency strategies, which consist firstly to reform domestic taxation and secondly, to strengthen international tax cooperation to improve the fight against fraud and tax evasion. It is then important that we pay attention in the relationship between the tax administration and the taxpayer. These include identifying the reasons for the lack of civism of the Guinean taxpayer. They boil down to a propensity of public financial administration, with significant powers, to bail out public funds facing taxpayers benefiting from weak legal guarantees, and a deep mistrust of the latter in the good management of the tax-paid, which requires measures extra-fis which requires criminal measures to ensure the effectiveness and the efficiency of public resources, thus taxThey boil down to a propensity of public financial administration, with significant powers, to replenish public funds facing taxpayers who receive only weak legal safeguards and a deep distrust of the latter on the good management of the tax paid, which requires extra tax measures to guarantee the effectiveness and efficiency of public resources, thus tax.

Pour lutter efficacement contre les phénomènes de fraude et d'évasion fiscales internationales favorisés par l'opacité des juridictions offshores et l'attractivité des paradis fiscaux, Je législateur a eu recours aux présomptions. Cette technique juridique a pour caractéristique de modifier la dialectique de la preuve en faveur de l'administration, qui n'est plus tenue de faire la démonstration de la fraude ou de l'évasion, mais seulement d'un ou de plusieurs faits connexes à l'infraction frauduleuse ou au fait d'optimisation fiscale abusive. En pratique, le législateur a souvent eu recours à des présomptions à la force renforcée, renversant directement le fardeau de la preuve sur le contribuable qui est d'emblée tenu d'établir la preuve d'un fait connexe exonératoire à l'infraction ou au fait abusif. Pour muscler leur efficacité, le législateur a également introduit des présomptions irréfragables, au couperet définitif. Les présomptions simples caractérisées par une clause anti-abus centrée sur l'objet ont pour particularité de faire peser sur le contribuable la charge d'une preuve qualitativement supérieure. Ces présomptions, dont l'actionnement est conditionné à la preuve d'un fait connexe par l'administration, représentent une catégorie hétérodoxe de dispositifs présomptif renforcés, obligeant le contribuable à faire un effort d'analyse sur les finalités des opérations, ce qui revient à lui faire supporter la charge de la preuve de l'absence d'abus de droit. L'emploi des présomptions se heurte essentiellement aux droits et liberté économiques communautaire et conventionnels, obligeant Je législateur à adapter les dispositifs présomptifs à ces contraintes. / In order to struggle efficiently against tax avoidance and tax evasion tendencies, enhanced by offshore jurisdictions, often lacking transparency, and tax havens with their attractive conditions, the lawmaker has enabled rebuttable and conclusive presumptions to be used in suing cases. These legal tricks favour Tax administrations in winning the argument, since those are no longer required to bring compelling evidence of tax avoidance or tax evasion. It is enough to prove a fraud, an offence or an aggressive tax optimisation process with one or several connected facts. In practice, the lawmaker is often using strengthened standards on presumption to reverse the burden of proof onto the taxpayer, who therefore must provide evidence for any exemptions from responsibility regarding the alleged offence or abuse. To improve these tools efficiency, the lawmaker has also designed conclusive ( or irrebuttable) presumptions. Usual presumptions are characterised by their emphasis on anti-abuse clauses, which oblige taxpayers to bring stronger evidences in lawsuit. For Tax authorities, these are part of a legal arsenal using connected facts against the defensor who carries the burden of proof related to tax monitoring operations in the absence of abuse of rights.

Le montant annuel de la fraude européenne à la carte de paiement se monte à plus d’1,5 milliard d’euros. Cette manne aiguise l’appétit des groupes criminels qui exploitent la moindre faille de la monétique (écosystème de la carte de paiement). Les cinq principaux acteurs de la monétique (porteurs, émetteurs, accepteurs, acquéreurs et systèmes de paiement) s’appuient pourtant sur des systèmes et réseaux normalisés dont la sécurité est encadrée par des standards internationaux contraignants. Néanmoins, la fraude monétique ne cesse de progresser alors que les moyens de lutte (étatiques, collaboratifs ou individuels) restent limités.Après étude de la fraude monétique, cette thèse propose différentes actions (passives,réactives et proactives) visant à améliorer la lutte contre la fraude monétique. D’abord,il convient de mieux connaître la fraude en étudiant la provenance des données volées et plus seulement leur usage. Ensuite l’expertise de ces fraudes doit être améliorée, en développant par exemple une captation du progrès scientifique. Une expertise qui doit être en partie transmise aux enquêteurs afin qu’ils puissent conduire leurs enquêtes. Enquêtes qui peuvent être dynamisées par des opérations réactives associant investigateurs et sachants techniques. Enfin, de manière proactive, les enquêtes et analyses de demain doivent être facilitées par les technologies monétiques conçues aujourd’hui. / Every year, payment card fraud exceeds 1.5 billion euros in Europe. Organised crime groups are exploiting any vulnerability possible to take a piece of this lucrative activity. Even though the five principal entities in the payment card industry (cardholders, issuers,acceptors, acquirers and payment system providers) are implementing binding security measures through out standardized systems and networks, fraud continues to increase. Efforts by the state, industry collaboration, and individuals have been unsuccessful in decreasing criminal advances. Having analysed the elements of payment card fraud, this thesis proposes several actions (passive, reactive and proactive) to help improve the fight against this fraud. First, itis relevant to gain knowledge of the source of the card details and not to focus only on its reuse. Next, forensic assessment has to be improved, for example by developing an increased scientific understanding of the technology. Such an expertise should then be passed on to investigators through effective training and knowledge transfer. Investigations should also be made more dynamic with reactive operations conducted in concert by investigators and technicians. Finally, in an ideal proactive spirit, future investigations and assessments should be oriented and facilitated by studying and influencing current payment card technology developments.

Com o avanço tecnológico e econômico, que facilitaram o processo de comunicação e aumento do poder de compra, transações com cartão de crédito tornaram-se o principal meio de pagamento no varejo nacional e internacional (Bolton e Hand , 2002). Neste aspecto, o aumento do número de transações com cartão de crédito é crucial para a geração de mais oportunidades para fraudadores produzirem novas formas de fraudes, o que resulta em grandes perdas para o sistema financeiro (Chan et al. , 1999). Os índices de fraudes têm mostrado que transações no comércio eletrônico (e-commerce) são mais arriscadas do que transações presencias em terminais, pois aquelas não fazem uso de processos seguros e eficientes de autenticação do portador do cartão, como utilização de senha eletrônica. Como os fraudadores se adaptam rapidamente às medidas de prevenção, os modelos estatísticos para detecção de fraudes precisam ser adaptáveis e flexíveis para evoluir ao longo do tempo de maneira dinâmica. Raftery et al. (2010) desenvolveram um método chamado Dynamic Model Averaging (DMA), ou Ponderação Dinâmica de Modelos, que implementa um processo de atualização contínuo ao longo do tempo. Nesta dissertação, desenvolvemos modelos DMA no espaço de transações eletrônicas oriundas do comércio eletrônico que incorporem as tendências e características de fraudes em cada período de análise. Também desenvolvemos modelos de regressão logística clássica com o objetivo de comparar as performances no processo de detecção de fraude. Os dados utilizados para tal são provenientes de uma empresa de meios de pagamentos eletrônico. O experimento desenvolvido mostra que os modelos DMA apresentaram resultados melhores que os modelos de regressão logística clássica quando analisamos a medida F e a área sob a curva ROC (AUC). A medida F para o modelo DMA ficou em 58% ao passo que o modelo de regressão logística clássica ficou em 29%. Já para a AUC, o modelo DMA alcançou 93% e o modelo de regressão logística clássica 84%. Considerando os resultados encontrados para os modelos DMA, podemos concluir que sua característica de atualização ao longo do tempo se mostra um grande diferencial em dados como os de fraude, que sofrem mudanças de comportamento a todo momento. Deste modo, sua aplicação se mostra adequada no processo de detecção de transações fraudulentas no ambiente de comércio eletrônico. / Regarding technological and economic development, which made communication process easier and increased purchasing power, credit card transactions have become the primary payment method in national and international retailers (Bolton e Hand , 2002). In this scenario, as the number of transactions by credit card grows, more opportunities are created for fraudsters to produce new ways of fraud, resulting in large losses for the financial system (Chan et al. , 1999). Fraud indexes have shown which e-commerce transactions are riskier than card present transactions, since those do not use secure and efficient processes to authenticate the cardholder, such as using personal identification number (PIN). Due to fraudsters adapt quickly to fraud prevention measures, statistical models for fraud detection need to be adaptable and flexible to change over time in a dynamic way. Raftery et al. (2010) developed a method called Dynamic Model Averaging (DMA), which implements a process of continuous updating over time. In this thesis, we develop DMA models within electronic transactions coming from ecommerce environment, which incorporate the trends and characteristics of fraud in each period of analysis. We have also developed classic logistic regression models in order to compare their performances in the fraud detection processes. The database used for the experiment was provided by a electronic payment service company. The experiment shows that DMA models present better results than classic logistic regression models in respect to the analysis of the area under the ROC curve (AUC) and F measure. The F measure for the DMA was 58% while the classic logistic regression model was 29%. For the AUC, the DMA model reached 93% and the classical model reached 84%. Considering the results for DMA models, we can conclude that its update over time characteristic makes a large difference when it comes to the analysis of fraud data, which undergo behavioral changes continuously. Thus, its application has proved to be appropriate for the detection process of fraudulent transactions in the e-commerce environment.

Em anos recentes, muitos algoritmos bio-inspirados têm surgido para resolver problemas de classificação. Em confirmação a isso, a revista Nature, em 2002, publicou um artigo que já apontava para o ano de 2003 o uso comercial de Sistemas Imunológicos Artificiais para detecção de fraude em instituições financeiras por uma empresa britânica. Apesar disso, não observamos, a luz de nosso conhecimento, nenhuma publicação científica com resultados promissores desde então. Nosso trabalho tratou de aplicar Sistemas Imunológicos Artificiais (AIS) para detecção de fraude em cartões de crédito. Comparamos AIS com os métodos de Árvore de Decisão (DT), Redes Neurais (NN), Redes Bayesianas (BN) e Naive Bayes (NB). Para uma comparação mais justa entre os métodos, busca exaustiva e algoritmo genético (GA) foram utilizados para selecionar um conjunto paramétrico otimizado, no sentido de minimizar o custo de fraude na base de dados de cartões de crédito cedida por um emissor de cartões de crédito brasileiro. Em adição à essa otimização, fizemos também uma análise e busca por parâmetros mais robustos via multi-resolução, estes parâmetros são apresentados neste trabalho. Especificidades de bases de fraude como desbalanceamento de dados e o diferente custo entre falso positivo e negativo foram levadas em conta. Todas as execuções foram realizadas no Weka, um software público e Open Source, e sempre foram utilizadas bases de teste para validação dos classificadores. Os resultados obtidos são consistentes com Maes et al. que mostra que BN são melhores que NN e, embora NN seja um dos métodos mais utilizados hoje, para nossa base de dados e nossas implementações, encontra-se entre os piores métodos. Apesar do resultado pobre usando parâmetros default, AIS obteve o melhor resultado com os parâmetros otimizados pelo GA, o que levou DT e AIS a apresentarem os melhores e mais robustos resultados entre todos os métodos testados. / In 2002, January the 31st, the famous journal Nature, with a strong impact in the scientific environment, published some news about immune based systems. Among the different considered applications, we can find detection of fraudulent financial transactions. One can find there the possibility of a commercial use of such system as close as 2003, in a British company. In spite of that, we do not know of any scientific publication that uses Artificial Immune Systems in financial fraud detection. This work reports results very satisfactory on the application of Artificial Immune Systems (AIS) to credit card fraud detection. In fact, scientific financial fraud detection publications are quite rare, as point out Phua et al. [PLSG05], in particular for credit card transactions. Phua et al. points out the fact that no public database of financial fraud transactions is available for public tests as the main cause of such a small number of publications. Two of the most important publications in this subject that report results about their implementations are the prized Maes (2000), that compares Neural Networks and Bayesian Networks in credit card fraud detection, with a favored result for Bayesian Networks and Stolfo et al. (1997), that proposed the method AdaCost. This thesis joins both these works and publishes results in credit card fraud detection. Moreover, in spite the non availability of Maes data and implementations, we reproduce the results of their and amplify the set of comparisons in such a way to compare the methods Neural Networks, Bayesian Networks, and also Artificial Immune Systems, Decision Trees, and even the simple Naïve Bayes. We reproduce in certain way the results of Stolfo et al. (1997) when we verify that the usage of a cost sensitive meta-heuristics, in fact generalized from the generalization done from the AdaBoost to the AdaCost, applied to several tested methods substantially improves it performance for all methods, but Naive Bayes. Our analysis took into account the skewed nature of the dataset, as well as the need of a parametric adjustment, sometimes through the usage of genetic algorithms, in order to obtain the best results from each compared method.

Le terme offshore est communément utilisé pour désigner la mise en place d'une entité juridique dans un pays où celle-ci n'exerce aucune activité. Par cette implantation, cette entité pourra bénéficier de certains avantages fiscaux. Or ce mécanisme d'optimisation fiscale peut être contourné de manière illégale. De nombreuses juridictions offshore ont alors été pointées du doigt pour leur manque de transparence et jugées responsables de l'évasion fiscale. Parmi ces centres financiers offshore, Maurice se distingue des autres places financières dans la mesure où elle s'attache à respecter les normes internationales tout en continuant de développer son secteur offshore. Ainsi, l'intérêt de cette thèse est de présenter les caractéristiques de chaque entité offshore et leur fonctionnement afin de comprendre comment elles peuvent être détournées de leur objet initial. Cette présentation passe dans un premier temps par l’analyse des entités offshore et leur exploitation puis dans un second temps leur régulation. On constate alors que la juridiction mauricienne est injustement qualifiée de paradis fiscal et encourent les mêmes risques que les plus grandes places offshore. Maurice a su ainsi concilier ses intérêts en trouvant un équilibre entre l’exploitation économique de son secteur offshore et l’application rigoureuse des normes internationales. / The term offshore is commonly used to refer to the establishment of a legal entity in a country where it has no business.For this implementation, this entity can entain certain tax benefits. But this tax optimization mechanism can be bypassed illegally. Many offshore jurisdictions were then blamed for their lack of transparency and held for tax evasion. Among these offshore financial centers, Mauritius differs from other financial markets as it strives to meet international standards while continuing to develop its offshore sector. Thus, the interest of this thesis is to present the characteristics of each offshore entity and its operations in order to understand how they can be diverted from their original purpose. This presentation is an analysis of each offshore entities, their operations and their regulation. We can found that the Mauritian juridiction is unfairly labeled as tax havens and face the same risks as the largest offshore places. Mauritius has thus reconcile its interests by finding a balance between the economic exploitation of its offshore sector and the strict application of international standards.

Ce document concerne le développement d'un cadre mathématique spécifiant une technologie capable de prendre en charge quelques unes des problématiques relevant du domaine des grands flux de données. Nous proposons de combiner le point de vue ontologique de Newell et celui épistémologique de Floridi d'abstraction pour construire des outils de transformation de modéles au moyen d'un ensemble adéquats de foncteurs au sens de la théorie des catégories de Samuel Eilenberg et Saunders Mac Lane. La méthode de résolution de problème proposée est basée sur un raisonnement d'abstraction temps réel qui produit, en ligne, une réduction d'un grand nombre de données sémantiquement pauvres en une donnée unique équivalente mais sémantiquement plus riche. Le prix à payer pour un tel enrichissement sémantique de l'information est la perte d'information syntaxique (i.e. le phénoméne d'oubli). Nos contributions sont les suivantes: (i) la démonstration que le concept d'observateur unaire de la théorie des observations datées (TOT) de Le Goc joue le même rôle qu'un échantillonneur de Dirac, (ii) la construction de la catégorie $TOT(\mathbb{Z})$, adéquate à la formulation du processus d'abstraction proposé et (iii) la conception de la méthode de résolution de problème TOM4A (timed observations methodology for abstraction) dont une application concrète est présentée visant à découvrir et modéliser le problème complexe de la fraude interne dans le domaine bancaire / This document concerns the development of a theoretical mathematical framework to provide a technology able to manage some of the problematics of the big data flows domain. We propose to combine Newell's ontological and Floridi's epistemological point of views of abstraction to build tools that transform models by the mean of an adequate set of functors according to Samuel Eilenberg and Saunders Mac Lane's category theory. The proposed problem solving method relies on a real time abstraction reasoning process to resume, on line, a lot of semantically poor data into an equivalent but richer one. The price to pay for such an information semantic enrichment is the loss of syntactic data (i.e. the oversight phenomenon). Our contributions are (i) to prove that Le Goc's timed observations theory (TOT) concept of unary observer plays the same role as Dirac's sampler, (ii) the construction of the $TOT(\mathbb{Z})$ category that is adequate to formulate the proposed abstraction based PSM and (iii) the design of TOM4A (timed observations methodology for abstraction), a specific recursive abstraction-reification based PSM whose a concrete application has been provided for detecting and modeling the complex problem of internal frauds in the banking industry

La légitimité du processus électoral est souvent remise en question par des candidats et membres de l’élite politique qui tente de justifier leurs défaites aux urnes. Par conséquent, plusieurs électeurs sont exposés à des allégations non-fondées de fraude électorale, et ce, même si la fraude électorale se produit très rarement dans les démocraties établies. Certaines études ont déjà déterminé que des affirmations trompeuses concernant l’intégrité des élections ont des effets négatifs sur la perception des citoyens face à l’impartialité électorale. En effet, des chercheurs ont montré que les allégations non-fondées de fraude électorale ébranlent la confiance que les électeurs ont envers le système électoral. Cependant, aucune étude n’a exploré l’effet potentiel de ces allégations sur la participation électorale. En utilisant des données de sondage originales collectées au Royaume-Uni, ce projet considère l’impact des affirmations de fraude électorale sur la décision d’aller voter ou non. En premier lieu, nous regardons l’effet sur les dispositions électorales spécifiques, c’est-à-dire la probabilité qu’un individu ira voter. Par la suite, nous testons la capacité de messages correctifs à rectifier les perceptions erronées des électeurs et limiter l’impact négatif des allégations de fraude électorale. Les résultats de l’expérience démontrent que l’exposition à des allégations non-fondées de fraude électoral n’a pas d’effet sur la participation des citoyens aux urnes. Cependant, des analyses supplémentaires permettent d’identifier une relation entre les perceptions de fraude et la décision d’aller voter. Considérant ces résultats, des explications alternatives sont présentées. / The legitimacy of the electoral process is often put into question by political candidates and elites who seek to account for their loss. As a result, a significant portion of voters are presented with unfounded allegations of widespread election fraud even though such fraud seldom occurs in consolidated democracies. Previous research has determined that misleading claims regarding the integrity of elections carry important implications for citizens’ perceptions of electoral fairness. In fact, scholars have shown unsubstantiated claims of election fraud to be detrimental to voters’ confidence in elections as well as their support for key democratic norms. However, the literature has yet to systematically explore the impact of electoral fraud allegations on voter participation. Using original survey data from the United Kingdom, this research measures the impact of unfounded allegations of election fraud on the decision to vote or not. We first look at the impact on specific dispositions of voting, that is, the likelihood that an individual will turn out at the next election. Then, we examine the ability of corrective messages to rectify misperceptions of electoral integrity and limit the negative impacts of fraud allegations on voter participation. The results of the survey experiment do not support the hypotheses according to which exposure to unfounded allegations of fraud influences confidence in elections and voter participation. However, results from supplementary analyses highlight an important relation between perceptions of fraud and subsequent desire to cast a ballot. Explanations for these findings are discussed.