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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Industrial timberland transactions in the United States: firm financial performance, timber supply, and welfare implications

Rahman, Mohammad Mahfuzur 09 December 2011 (has links)
In the last two decades, many firms in the U.S. forest products industry have either divested their timberlands or converted their corporate structures from C corporations to real estate investment trusts (REITs). This study hypothesizes that this large-scale timberland ownership change affects the financial performance of firms involved in divestitures and on timber supply and, as a result, the economic surplus of producers and consumers in the U.S. timber markets. These issues have not been adequately addressed in existing literature. Event analysis and equilibrium displacement models were employed to address firm financial performance in the capital markets and welfare implications in U.S. timber markets, respectively. The capital markets responded to divestiture events by significantly improving buying firms’ and REITs’ market value. Annual average timberland ownership changes resulted in a net reduction of timber supply which, in turn, caused total social surplus to decrease by $43 million on annual rate of timberland ownership change basis. Compared to over $33 billion U.S. timber markets, this surplus reduction was small. Thus, this study helps justify timberland ownership change decisions and explains the nature and extent of surplus shifts among producers and consumers when timberlands change hands.
2

Fraturas e caminhos ?timos na rede de Barabasi-Albert

Nunes, Thiago Cris?stomo Carlos 29 June 2012 (has links)
Made available in DSpace on 2014-12-17T15:15:01Z (GMT). No. of bitstreams: 1 ThiagoCCN_DISSERT.pdf: 2332508 bytes, checksum: bbc84148d8aa1acc5070a5a68ca8b3b6 (MD5) Previous issue date: 2012-06-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Following the study of Andrade et al. (2009) on regular square lattices, here we investigate the problem of optimal path cracks (OPC) in Complex Networks. In this problem we associate to each site a determined energy. The optimum path is defined as the one among all possible paths that crosses the system which has the minimum cost, namely the sum of the energies along the path. Once the optimum path is determined, at each step, one blocks its site with highest energy, and then a new optimal path is calculated. This procedure is repeated until there is a set of blocked sites forming a macroscopic fracture which connects the opposite sides of the system. The method is applied to a lattice of size L and the density of removed sites is computed. As observed in the work by Andrade et al. (2009), the fractured system studied here also presents different behaviors depending on the level of disorder, namely weak, moderated and strong disorder intensities. In the regime of weak and moderated disorder, while the density of removed sites in the system does not depend of the size L in the case of regular lattices, in the regime of high disorder the density becomes substantially dependent on L. We did the same type of study for Complex Networks. In this case, each new site is connected with m previous ones. As in the previous work, we observe that the density of removed sites presents a similar behavior. Moreover, a new result is obtained, i.e., we analyze the dependency of the disorder with the attachment parameter m / Seguindo a linha do trabalho de Andrade e colaboradores (2009) em redes regulares, n?s investigamos o problema da fratura atrav?s do caminho ?timo (optimal path cracks -OPC) em Redes Complexas. Neste problema n?s associamos para cada s?tio uma determinada energia. O caminho ?timo ? definido como aquele, dentre todos os poss?veis, que atravessa o sistema e tem o menor custo, ou seja, a menor soma das energias ao longo do caminho. Uma vez que o caminho ?timo ? determinado, em cada passo, n?s bloqueamos o s?tio com maior energia e a partir de ent?o um novo caminho ?timo ? calculado. Este procedimento ? repetido at? que existe um conjunto de s?tios bloqueados que forma uma fratura macrosc?pica a qual conecta lados opostos do sistema. O m?todo ? aplicado numa rede de lado L e a densidade de s?tios removidos ? computada. Como observado no trabalho de Andrade e colaboradores, o sistema fraturado que n?s estudamos tamb?m apresenta diferentes comportamentos dependendo do n?vel da desordem, que pode ser fraca, moderada ou forte. No regime de desordem fraca e moderada, a densidade de s?tios removidos no sistema n?o depende do tamanho L no caso de redes regulares, enquanto no regime de desordem forte a densidade se torna substancialmente dependente de L. N?s fizemos o mesmo tipo de estudo para Redes Complexas. Numa rede complexa caso, cada novo s?tio ? conectado a m s?tios que j? est?o presentes na rede. Como no trabalho anterior, n?s observamos que a densidade de s?tios removidos apresenta um comportamento similar. Al?m disso, um novo resultado ? obtido, isto ?, n?s analisamos a depend?ncia da desordem com o par?metro de liga??o m

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