A reforma da ONU e a importância de um novo Conselho de Segurança

As transformações a nível mundial ocorridas nos últimos anos, com especial destaque para o fim da guerra fria, a emergência de novos atores e de novas ameaças e a globalização em todos os setores, contribuíram para uma grande instabilidade nas relações internacionais, onde observa-se uma conflitualidade latente. As transformações ocorridas também evidenciaram vulnerabilidades e deficiências da Organização das Nações Unidas, que vem perdendo credibilidade, não só pelas suas insuficiências, mas também pelas intervenções unilaterais de seu membro mais proeminente, os Estados Unidos da América. Pelo fato de ser um fórum difícil de substituir, pela sua legitimidade ímpar para assegurar a paz e a segurança internacionais, sua reestruturação afigura-se como necessária e fundamental a fim de manter uma estabilidade e diálogo entre as nações, contribuindo decisivamente para uma segurança global. Este estudo procura identificar as razões que justificam uma reforma das Nações Unidas, em particular do seu Conselho de Segurança, o estágio em que se encontram as negociações e o impacto vislumbrado na atual conflitualidade mundial em decorrência de sua não realização

Acoustic echo cancellation using sub-band encoded training sequences

An acoustic echo canceler (AEC) enhances speech quality by removing echoes. An AEC operates by estimating the acoustic path, e.g., transfer function, between a speaker and a microphone. A training sequence of symbols, known a priori, is transmitted to probe the acoustic environment between the speaker and microphone and used to determine the transfer function. The transfer function is used to cancel echoes from the signal produced by the microphone. The performance of an AEC is affected by various factors such as a dynamic acoustic path, multiple acoustic paths, presence of background noise, etc. In certain conditions, the time required for robust estimation of the transfer function can be such that the transfer function changes during the estimation. Repeated transmittal of the training sequence can improve transfer function estimates; however, the training sequence itself occupies bandwidth that can otherwise carry speech payload. Techniques of this disclosure achieve robust AEC performance by transmitting pseudo-random training sequences at spectral regions unoccupied by speech, in a manner imperceptible to the human ear. The transfer function can be estimated and updated nearly continuously and imperceptibly

An Object-Oriented Programming Environment for Parallel Genetic Algorithms

This thesis investigates an object-oriented programming environment for building parallel applications based on genetic algorithms (GAs). It describes the design of the Genetic Algorithms Manipulation Environment (GAME), which focuses on three major software development requirements: flexibility, expandability and portability. Flexibility is provided by GAME through a set of libraries containing pre-defined and parameterised components such as genetic operators and algorithms. Expandability is offered by GAME'S object-oriented design. It allows applications, algorithms and genetic operators to be easily modified and adapted to satisfy diverse problem's requirements. Lastly, portability is achieved through the use of the standard C++ language, and by isolating machine and operating system dependencies into low-level modules, which are hidden from the application developer by GAME'S application programming interfaces. The development of GAME is central to the Programming Environment for Applications of PArallel GENetic Algorithms project (PAPAGENA). This is the principal European Community (ESPRIT III) funded parallel genetic algorithms project. It has two main goals: to provide a general-purpose tool kit, supporting the development and analysis of large-scale parallel genetic algorithms (PGAs) applications, and to demonstrate the potential of applying evolutionary computing in diverse problem domains. The research reported in this thesis is divided in two parts: i) the analysis of GA models and the study of existing GA programming environments from an application developer perspective; ii) the description of a general-purpose programming environment designed to help with the development of GA and PGA-based computer programs. The studies carried out in the first part provide the necessary understanding of GAs' structure and operation to outline the requirements for the development of complex computer programs. The second part presents GAME as the result of combining development requirements, relevant features of existing environments and innovative ideas, into a powerful programming environment. The system is described in terms of its abstract data structures and sub-systems that allow the representation of problems independently of any particular GA model. GAME's programming model is also presented as general-purpose object-oriented framework for programming coarse-grained parallel applications. GAME has a modular architecture comprising five modules: the Virtual Machine, the Parallel Execution Module, the Genetic Libraries, the Monitoring Control Module, and the Graphic User Interface. GAME's genetic-oriented abstract data structures, and the Virtual Machine, isolates genetic operators and algorithms from low-level operations such as memory management, exception handling, etc. The Parallel Execution Module supports GAME's object- oriented parallel programming model. It defines an application programming interface and a runtime library that allow the same parallel application, created within the environment, to run on different hardware and operating system platforms. The Genetic Libraries outline a hierarchy of components implemented as parameterised versions of standard and custom genetic operators, algorithms and applications. The Monitoring Control Module supports dynamic control and monitoring of simulations, whereas the Graphic User Interface defines a basic framework and graphic 'widgets' for displaying and entering data. This thesis describes the design philosophy and rationale behind these modules, covering in more detail the Virtual Machine, the Parallel Execution Module and the Genetic Libraries. The assessment discusses the system's ability to satisfy the main requirements of GA and PGA software development, as well as the features that distinguish GAME from other programming environments

Histological and framboidal textures in diagenetic pyrite from the gondwana coal beds,Brazil

Nas camadas de carvão do Grupo Tubarão, depositadas na Bacia do Paraná, no sul do Brasil, ocorre pirita. As piritas do carvão da região de Cambui, na Bacia do Rio do Peixe, estudadas em seção polida, apresentam texturas framboidal e histológicas que são interpretadas como evidências de piritas 'singenéticas, depositadas durante a diagênese. Marcassita subordinada, que ocorre como veios e em bandas concêntricas de textura coloforme, indicaria formação num meio localmente acidificado. As estruturas anatômicas observadas nas seções polidas de pirita correspondem a partes de sistema vascular complexo de plantas fósseis, que sugerem a revisão da idéia corrente de possíveis afinidades de formas do Hemisfério Sul com as do Hemisfério Norte.Pyrite occurs in the Gondwana coal measures of the Tubarão Group, in the Paraná sedimentary basin, Southern Brazil. Polished sections of pyrite from the Carnbui area show framboidal and histological textures which are interpreted as evidence for the syngenetic origin of the pyrite, deposited during diagenesis. Subordinate marcasite, which occurs as secondary veins and concentric bands with colloform textures, would indicate formation in a locally acid environment. The anatomical structures observed in polished sections of pyrite show parts of a complex vascular system which suggests that current opinion concerning the affinities of the forms of the Southern Hemisphere with those of the Northern Hemisphere should be revised

The role of the abandonment option in strategic capital allocation: a review of selected literature

We review the most relevant contributions to the abandonment option since the late 1960s. We begin by approaching the contributions to the literature before the emergence of the real options approach to capital investment decisions, and thereafter, under a consistent real options approach, highlighting the interactions between the option to abandon and other types of options. We then identify the methodologies adopted, and the business sectors/ types of investment projects where the abandonment option is more frequently studied. We also debate the strategic role of the abandonment solution in corporate divestitures and under a game-theoretical approach. Finally, we present some concluding remarks and identify how certain gaps found in the literature may constitute opportunities for future research

Guia de excursão pedológica do XXX Congresso Brasileiro de Ciência do Solo: solos da Zona da Mata de Pernambuco

bitstream/CNPS-2010/14872/1/doc72-2005-guia-excursao-pedologicaxxx.pd

Paradoxo da razão no caos. Teoria do caos aplicada na das probabilidades

São estabelecidas as bases de um ensaio sobre a aplicabilidade da Ciência da Computação, sustentadas pela Teoria do Caos, para resolução de certas questões tipicamente probabilísticas onde, através de experimentos computacionais conclusivos, as evidências apontam para o fato de que há fortes indícios a favor deste estudo. O estudo consiste em mostrar um paradoxo que é criado em situações específicas na Teoria das Probabilidades porque elas de fato estão intrinsecamente relacionadas a questões sistemáticas que têm tendência ao comportamento caótico e, portanto, próprias para as soluções que emergem da Teoria do Caos. É apresentado o Teorema da Probabilidade Sistematizada provado quando mostramos ser falsa a seguinte declaração por ir de encontro à Teoria do Caos: em uma simulação do caos, não é possível prever uma tendência ao comportamento caótico