Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-08-24T14:28:42Z No. of bitstreams: 1 Carlos Eduardo Ferreira Mardini_.pdf: 679225 bytes, checksum: 9b73833a0529d2235e32c1995bf6fe5e (MD5) / Made available in DSpace on 2017-08-24T14:28:42Z (GMT). No. of bitstreams: 1 Carlos Eduardo Ferreira Mardini_.pdf: 679225 bytes, checksum: 9b73833a0529d2235e32c1995bf6fe5e (MD5) Previous issue date: 2017-05-29 / Nenhuma / O presente estudo teve como objetivo investigar os determinantes da perda de recuperabilidade de ativos, nas empresas brasileiras listadas na BM&FBOVESPA, no período de 2010 a 2014. Sua importância se dá a partir da Lei n° 11.638/09 que torna obrigatório, a partir de 2010, o teste de redução ao valor recuperável de ativos, no mínimo, anualmente. Para tanto, foi utilizada a abordagem quantitativa, com a finalidade de demonstrar a relação estatística entre o impairment reconhecido pela empresa e o valor de mercado, o ativo, o patrimônio líquido, o investimento, o imobilizado e o resultado do exercício e para testar a hipótese nula de que não existe essa relação utilizou-se o teste de Mann-Whitney. A população foi composta por 346 empresas brasileiras, abertas, ativas, e que negociam ações na BM&FBOVESPA. Para a amostra final, considerou-se 28 empresas que tiveram mensuração do impairment nesses grupos daquele período. A análise dos resultados evidenciou que: (i) o setor de Petróleo e Gás obteve a maior perda, seguido de Energia Elétrica e Têxtil. Em relação aos outros resultados obtidos levou-se em consideração a variável dependente e sua relação com às variáveis independentes onde foi possível observar no que se refere ao impairment registrado que o aumento de uma unidade nesse coeficiente foi acarretado por (ii) uma diminuição no coeficiente do valor de mercado; (iii) uma diminuição no coeficiente do ativo; (iv) um aumento no coeficiente do patrimônio líquido; (v) uma diminuição no coeficiente do investimento; (vi) uma diminuição no coeficiente do ativo total;(vii) uma diminuição no coeficiente da dívida; (viii) uma diminuição no coeficiente do EBITDA; (iv) um aumento no coeficiente do setor. / The present study aimed to investigate the determinants of asset impairment loss, the Brazilian companies listed on the BM&FBOVESPA, in the period from 2010 to 2014. Its importance is given from the law No. 11,638/09 that makes it compulsory, from 2010, the decrease in recoverable value of assets at least annually. To this end, quantitative approach was used, with the purpose of demonstrating the statistical relationship between the impairment recognized by the company and the market value, the active, the equity, the investment, fixed assets and the profit or loss for the financial year and to test the null hypothesis that there is no such relation using Mann-Whitney's test. The population was composed of 346 companies, open, active, and who trade shares on BM&FBOVESPA. For the final sample, 28 companies that had the impairment in these groups of that period. The analysis of the results showed that: (i) the oil and gas sector got the biggest loss, followed by power and textile. In relation to other results took into account the dependent variable and your relationship with independent variables where it was possible to observe with regard to impairment recorded that the increase of one unit in this coefficient was led by (ii) a decrease in the coefficient of market value; (iii) a decrease in the coefficient of active; (iv) an increase in the coefficient of net equity; (v) a decrease in the coefficient of investment; (vi) a decrease in the coefficient of total assets; (vii) a decrease in the coefficient of debt; (viii) a decrease in the coefficient of EBITDA; (iv) an increase in the coefficient.

[pt] A presente tese apresenta e discute metodologias para prever o volume de óleo recuperável em bacias petrolíferas e explicar a evolução do processo de descoberta. A evolução do processo de descoberta é modelada pelo produto de duas funções matemáticas de tendências opostas: a função seleção de controle, crescente, que representa o grau de conhecimento e informação adquiridos na região de exploração, e a função seleção de condições, decrescente, indicando que a condição de exploração piora em conseqüência da depleção da área considerada. São propostas três novas metodologias que utilizam funções de controle nãolineares para explicar a influência do progresso tecnológico no acréscimo dos volumes recuperáveis. Além disso, utiliza-se o esforço exploratório, representado pela quantidade de poços já perfurados, como variável explicativa para as funções de controle e condição. As metodologias acima mencionadas foram testadas utilizando dados históricos referentes a cinco bacias petrolíferas. Após avaliar a capacidade explicativa dos modelos através do ajuste aos dados históricos, foram feitas previsões (out of sample) para um horizonte de 3 e 10 anos com o objetivo de avaliar a capacidade preditiva. Os testes feitos com dados de quatro diferentes bacias indicam que o uso do esforço de perfuração como variável explicativa pode melhorar a previsão a longo prazo. A análise nos resíduos dos modelos propostos indica que os modelos têm boa capacidade explicativa, pois capturaram a informação contida nos dados descrevendo satisfatoriamente o processo de evolução de descobertas nas séries observadas. / [en] This dissertation presents methodologies to forecast the recoverable oil volume in sedimenary basins and to explain the evolution of the discovery process. The evolution of the discovery process is modeled as the product of two mathematical functions of opposing trends, namely, the control function, increasing, which represents the degree of knowledge and information acquired in the exploration region, and the condition function, decreasing, indicating that the exploration condition worsens with time as a consequence of the area depletion. Three new methodologies are proposed using nonlinear control functions to explain the influence of technological progress in the reserves accrual. Acting as a proxy for exploratory effort, the drilling footage is used as an explanatory variable for both the control and the condition functions. The aforementioned methodologies were tested using a dataset of five petroliferous basins. After evaluating the explicative capacity by fitting the models to the historical data, out of sample forecast were made for a horizon of 3 and 10 years. The results using a dataset of four different basins indicate that the drilling footage can improve the long-term forecast. The analysis in the residues of the proposed models indicates that the models captured the information contained in the data and satisfactorily describes the process of evolution of discoveries in the observed series.

This article addresses the topic of civil wrongful acts that can cause tort liability. The author criticize the position that holds that wrongfulness is not an element of tort liability. In accordance with that position, not considering wrongfulness as an element of tort liability, it permits to consider that some “lawful acts” could cause tort liability. On the contrary, Espinoza consider those supposed “lawful acts” as examples of abuse of law so they are actually wrongful acts. / El presente artículo aborda el tema de los llamados actos ilícitos dañosos como supuestos de responsabilidad civil. El autor cuestiona la posición que niega que la antijuridicidad sea un elemento configurador de la misma. El autor cuestiona el argumento basado en que el no considerar la antijuridicidad permitiría el resarcimiento de los “actos lícitos dañosos”. Por el contrario, se sostiene en el presente artículo que dichos actos serían supuestos de abuso del derecho. Por tanto, tales actos serían considerados como actos ilícitos dañosos.

New techniques,languages and paradigms have facilitated the creation of distributed applications in several areas. Perhaps the most promising paradigm is the one that incorporates the mobile agent concept. A mobile agent in a large scale network can be viewed as a software program that travels through a heterogeneous network, crossing various security domains and executing autonomously in its destination. Mobile agent technology extends the traditional network communication model by including mobile processes, which can autonomously migrate to new remote servers. This basic idea results in numerous benefits including flexible, dynamic customisation of the behavior of clients and servers and robust interaction over unreliable networks. In spite of its advantages, widespread adoption of the mobile agent paradigm is being delayed due to various security concerns. Currently available mechanisms for reducing the security risks of this technology do not e±ciently cover all the existing threats. Due to the characteristics of the mobile agent paradigm and the threats to which it is exposed, security mechanisms must be designed to protect both agent hosting servers and agents. Protection to agent-hosting servers' security is a reasonably well researched issue, and many viable mechanisms have been developed to address it. Protecting agents is technically more challenging and solutions to do so are far less developed. The primary added complication is that, as an agent traverses multiple servers that are trusted to different degrees, the agent's owner has no control over the behaviors of the agent-hosting servers. Consequently the hosting servers can subvert the computation of the passing agent. Since it is infeasible to enforce the remote servers to enact the security policy that may prevent the server from corrupting agent's data, cryptographic mechanisms defined by the agent's owner may be one of the feasible solutions to protect agent's data.Hence the focus of this thesis is the development and deployment of cryptographic mechanisms for securing mobile agents in an open environment. Firstly, requirements for securing mobile agents' data are presented. For a sound mobile agent application, the data in an agent that is collected from each visiting server must be provided integrity. In some applications where servers intend to keep anonymous and will reveal their identities only under certain cir- cumstances, privacy is also necessitated. Aimed at these properties, four new schemes are designed to achieve different security levels: two schemes direct at preserving integrity for the agent's data, the other two focus on attaining data privacy. There are four new security techniques designed to support these new schemes. The first one is joint keys to discourage two servers from colluding to forge a victim server's signature. The second one is recoverable key commitment to enable detection of any illegal operation of hosting servers on an agent's data. The third one is conditionally anonymous digital signature schemes, utilising anonymous public-key certificates, to allow any server to digitally sign a document without leaking its identity. The fourth one is servers' pseudonyms that are analogues of identities, to enable servers to be recognised as legitimate servers while their identities remain unknown to anyone. Pseudonyms can be deanonymised with the assistance of authorities. Apart from these new techniques, other mechanisms such as hash chaining relationship and mandatory verification process are adopted in the new schemes. To enable the inter-operability of these mechanisms, a security architecture is therefore developed to integrate compatible techniques to provide a generic solution for securing an agent's data. The architecture can be used independently of the particular mobile agent application under consideration. It can be used for guiding and supporting developers in the analysis of security issues during the design and implementation of services and applications based on mobile agents technology.