Automatic text summarization has achieved remarkable success with the development of deep neural networks and the availability of standardized benchmark datasets. It can generate fluent, human-like summaries. However, the unreliability of the existing evaluation metrics hinders its practical usage and slows down its progress. To address this issue, we propose an automatic reference-less text summarization evaluation system with dynamically generated synthetic facts. We hypothesize that if a system guarantees a summary that has all the facts that are 100% known in the synthetic document, it can provide natural interpretability and high feasibility in measuring factual consistency and comprehensiveness. To our knowledge, our system is the first system that measures the overarching quality of the text summarization models with factual consistency, comprehensiveness, and compression rate. We validate our system by comparing its correlation with human judgment with existing N-gram overlap-based metrics such as ROUGE and BLEU and a BERT-based evaluation metric, BERTScore. Our system's experimental evaluation of PEGASUS, BART, and T5 outperforms the current evaluation metrics in measuring factual consistency with a noticeable margin and demonstrates its statistical significance in measuring comprehensiveness and overall summary quality.

This dissertation is dedicated to a comprehensive study of static synchronous compensator (STATCOM) systems utilizing cascaded-multilevel converters (CMCs). Among flexible AC transmission system (FACTS) controllers, the STATCOM has shown feasibility in terms of cost-effectiveness in a wide range of problem-solving abilities from transmission to distribution levels. Referring to the literature reviews, the CMC with separated DC capacitors is clearly the most feasible topology for use as a power converter in the STATCOM applications. The controls for the CMC-based STATCOM were, however, very complicated. The intricate control design was begun without well-defined system transfer functions. The control compensators were, therefore, randomly selected. The stability of the system was achieved by trial and error processes, which were time-consuming and ineffective. To be able to operate in a high-voltage application, a large number of DC capacitors are utilized in a CMC-based STATCOM. All DC capacitor voltages must be balanced in order to avoid over-voltages on any particular link. Not only do these uneven DC voltages introduce voltage stress on the semiconductor switches, but they also lower the quality of the synthesized output waveforms of the converter. Previous researches into DC capacitor voltage-balancing techniques were very straightforward, in that individual voltage compensators were added into the main control loop. However, the compensator design for these individual loops is very problematic because of the complexity of the voltage-loop transfer functions. Basically, the trial and error technique again provides the simplest way to achieve acceptable compensators. Moreover, the greater number of voltage levels, the more complex the control design, and the main controller must perform all of the feedback control procedures. As a result, this approach potentially reduces the reliability of the controller. The goal of this dissertation is to achieve high-performance, reliable, flexible, cost-effective power stages and controllers for the CMC-based STATCOM. Major contributions are addressed as follows: 1) optimized design for the CMC-based STATCOM power stages and passive components, 2) accurate models of the CMC for reactive power compensations in both ABC and DQ0 coordinates, 3) an effective decoupling power control technique, 4) DC-link balancing strategies; and 5) improvements in the CMC topology. To enhance the modularity and output voltage of the CMC, the high-switching-frequency, high-power H-bridge building block (HBBB) and the optimized design for its power stage and snubber circuits are first proposed. The high-switching-frequency feature is achieved by utilizing the Virginia Tech-patented emitter turn-off (ETO) thyristor. Three high-power HBBB prototypes were implemented, and their performance was experimentally verified. To simplify the control system design, well-defined models of the CMC in both ABC and DQ0 coordinates are proposed. The proposed models are for the CMC with any number of voltage levels. The key system transfer functions are achieved and used in the control design processes. To achieve independent power control capability, the control technique, called the decoupling power control, is proposed. By applying this control technique, real and reactive power components can be controlled separately. In order to balance the DC capacitor voltages, a new, effective pulse width modulation (PWM) technique, which is suitable for any number of H-bridge converters, is proposed. The proposed cascaded PWM algorithm can be practically realized into the field programmable gate arrays (FPGA), and its complexity is not affected by the number of voltage levels. In addition, the complexity of the main controller, which is essentially based on the digital signal processor (DSP), is no longer a function of the number of the output voltage levels. The basic structure of the cascaded PWM is modular, which, in general, enhances the modularity of the CMC power stages. With the combination of the decoupling power control and the cascaded PWM, a CMC with any number of voltage levels can be simply modeled as a three-level cascaded converter, which is the simplest topology to deal with. This significantly simplifies and optimizes the control design process. To verify the accuracy of the proposed models and the performance of the control system for the CMC-based STATCOM, a low-power, seven-level cascaded-based STATCOM hardware prototype is implemented. The key control procedures are performed by a main controller, which consists of a DSP and an FPGA. The simulation and experimental results indicate the superior performance of the proposed control system, as well as the precision of the proposed models. / Ph. D.

In this thesis, I explore the concept of a scientific fact through the work of Polish physician Ludwik Fleck (1896-1961). Fleck has had an alleged influence upon contemporary philosophy of science, primarily through the work of Thomas Kuhn with subsequent echoes from the direction of the sociology of science. Most writers, however, have restricted their focus upon only one of Fleck's publications, The Genesis and Development of a Scientific Fact (1935), and have highlighted the Polish philosophical community as a primary influence upon Fleck's ideas. I argue in this thesis that since Fleck was a doctor by trade, his views must be understood in the context of the medical issues and philosophy of medicine of his time. Furthermore, in order to appreciate Fleck's concept of a scientific fact, one must turn to his other philosophical works. A more judicious picture of Fleck and his concept of a scientific fact is provided by this analysis even though, I conclude, his approach remains philosophically unsatisfactory. / Master of Arts

In this case study, the author explores the nonprofit mission statement as a genre, its place within a genre ecology, and its communication through various genres. Theorizing the mission statement as a controlling and stabilizing force in a genre ecology, the author notes the potential of the mission statement to enact the genre function, "the authority a genre has even in the absence of its author. Noting the limitations of current genre ecology modeling (GEM), the author maps the genres, documents, and activities of a small community foundation using a revised form of GEM that more purposefully includes speech genres to map relationships; in this case study, the speech genres revealed how the mission statement is mediated through genres and activities. Further, observations and interviews revealed ideological conflicts of the organization's key stakeholders that resulted in clashes between key stakeholder values and the language of the nonprofit's mission (and other genres). Additionally, ideological consensus resulted in the addition of new organizational activities and genres, even though these activities are not in line with the language of the mission statement as written. Eventually, these activities become social facts, "ideas that the key stakeholders believe are in line with the mission when they are, in fact, in conflict with it. If these social facts are not re-aligned with the mission statement, new activities and genres are created and mediated by speech genres, potentially moving the organization further away from its purpose and goals. The author ultimately suggests a cycle of genre and activity production that will realign the social facts and the mission statement and encourage organizational leaders to return to the mission statement and change the language to reflect the organization's new reality. / Ph. D.

No / Legal arguments and judgements ostensibly rely for their credibility and persuasiveness on the presentation of factual claims and determination of facts through due process. While it should follow that proceedings that are undermined by disregard for facticity and due process should not appear credible or persuasive, in practice this is not always the case. In cases where narratives are not firmly underpinned by factuality and due process a series of narrative techniques and processes can be brought into play to enhance the persuasiveness and credibility of those narratives. These processes include the reliance on a narrative trajectory, the presentation of consensus, drawing on supportive discourses, the privileging of certain narrators and the smoothing over of contradictory evidence. This paper examines these processes in the case of P,C&S vs United Kingdom in which in the absence of fact and due process a local authority and the domestic courts in the UK constructed and confirmed a narrative of a dangerous mother.

Os sistemas elétricos de potência são frequentemente submetidos a perturbações causadas, por exemplo, por um aumento súbito de carga ou por um curto-circuito em uma linha de transmissão. Estas perturbações podem gerar oscilações eletromecânicas no sistema, uma vez que a velocidade dos geradores oscila. Para reduzir tais oscilações, controladores de sistema de potência são utilizados sendo, os mais comuns, controladores do tipo PSS (Power System Stabilizer). Porém, em alguns sistemas, somente o emprego de PSSs não é suficiente para garantir um nível mínimo satisfatório de amortecimento, sendo necessário recorrer a outros tipos de controladores. Desta forma, controladores do tipo FACTS (Flexible Alternating Current Transmission System), principalmente o TCSC (Thyristor Controlled Series Capacitor) se tornaram uma alternativa atraente no auxílio ao amortecimento dos sistemas de potência. O controle do TCSC é feito por um controlador POD (Power Oscilation Damper) que é empregado como controle suplementar do dispositivo. No entanto, apenas o emprego dos controladores não garante um bom amortecimento, fazendo-se necessária uma boa sintonia dos mesmos. A sintonia destes controladores é, na maioria das vezes, feita de forma manual, ou seja, usando o método de tentativa e erro, podendo demandar um tempo relativamente elevado, mesmo que feita por um engenheiro experiente. Para evitar que o projetista dispense tempo procurando uma sintonia adequada para os controladores, métodos automáticos de sintonia vêm sendo estudados. Tais métodos têm como principal vantagem a sintonia dos controladores considerando vários pontos de operação do sistema simultaneamente, fazendo com que o controlador seja robusto para variações em seu ponto de operação nominal. Os métodos automáticos de sintonia utilizam métodos de otimização local ou métodos de otimização global. Os métodos de busca local têm a rapidez como principal vantagem, porém podem não convergir para um valor satisfatório de amortecimento estipulado pelo projetista. Os métodos de busca global, em grande parte das vezes, convergem para um valor de amortecimento solicitado pelo projetista, porém em um tempo elevado. Este trabalho propõe um método de sintonia dos controladores utilizando uma estrutura híbrida, ou seja, algoritmos de busca global juntamente com algoritmos de busca local. Primeiramente uma busca global é feita pelo algoritmo até que um critério de parada, definido pelo projetista, seja alcançado (geralmente um valor de amortecimento mínimo para o sistema). Assim, os parâmetros dos controladores sintonizados pela busca global serão entrada de um método de busca local. O algoritmo de busca local tende a refinar a sintonia dos controladores aumentando, assim, o amortecimento do sistema até um valor especificado pelo projetista. Neste trabalho a busca global é realizada por um algoritmo genético enquanto que a busca local é feita por um algoritmo baseado no gradiente descendente da função objetivo (neste caso o amortecimento). As principais vantagens do algoritmo proposto são a diminuição do tempo de sintonia e o esforço computacional, se comparado a métodos de busca global, verificadas nos resultados do trabalho. / Electric Power Systems are constantly subjected to perturbations, which can be caused for several different reasons, e.g., due to a sudden load increase or a short circuit in a transmission line. These perturbations can induce electromechanical oscillations in the power system, since the angular speed of the generators oscillates. To reduce such oscillations, power system controllers are used, and the most common ones are the PSSs (Power System Stabilizers). In some systems, however, the usage of PSSs is not sufficient to guarantee a satisfactory level for the minimum damping, being necessary the usage of other types of controllers. Hence, FACTS (Flexible Alternating Current Transmission System) controllers, specially the TCSC (Thyristor Controlled Series Capacitor), became an attractive alternative to enhance the damping of electric power systems. The TCSC control action is performed by a POD (Power Oscillation Damper) controller, which is a supplementary control function of the device. However, it is not only the usage of such controllers that guarantees a sufficient damping, but also a good tuning of their parameters. The tuning of such controllers is ordinarily performed manually, using a trial-and-error method, which can last for a long time, even for experienced engineers. To facilitate the designers work in the tuning of the controllers parameters, automatic tuning methods are being studied. Such methods have the main advantage of considering several operating points of the system simultaneously, yielding a robust controller regarding variations in its nominal operating point. The aforementioned automatic tuning methods use local optimization methods or global optimization methods. The local optimization methods have the speed as the main advantage, but they can have convergence issues in the search for the minimum satisfactory damping threshold desired by the designer. The global optimization methods, on the other hand, ordinarily converge for the desired minimum damping threshold, but with large convergence times. This work proposes a controller tuning method using a hybrid structure, i.e., global search methods with local search methods. Initially, a global search is performed by the algorithm until a stop criteria is met, as defined by the designer (usually a minimum damping for the system). Thus, the controller parameters tuned by the global search method are the input values of a local search method. The local search algorithm actually refines the controllers tuning, increasing the system damping to the value defined by the designer. In this work the global search is performed by a genectic algorithm while the local search is performed by an algorithm based in the gradient descent of objective function (damping in this case). The greatest advantages of the proposed algorithm are the possible decrease in computational time and effort, when compared to global search methods, verified in the work results.

Os sistemas elétricos de potência são frequentemente submetidos a perturbações causadas, por exemplo, por um aumento súbito de carga ou por um curto-circuito em uma linha de transmissão. Estas perturbações podem gerar oscilações eletromecânicas no sistema, uma vez que a velocidade dos geradores oscila. Para reduzir tais oscilações, controladores de sistema de potência são utilizados sendo, os mais comuns, controladores do tipo PSS (Power System Stabilizer). Porém, em alguns sistemas, somente o emprego de PSSs não é suficiente para garantir um nível mínimo satisfatório de amortecimento, sendo necessário recorrer a outros tipos de controladores. Desta forma, controladores do tipo FACTS (Flexible Alternating Current Transmission System), principalmente o TCSC (Thyristor Controlled Series Capacitor) se tornaram uma alternativa atraente no auxílio ao amortecimento dos sistemas de potência. O controle do TCSC é feito por um controlador POD (Power Oscilation Damper) que é empregado como controle suplementar do dispositivo. No entanto, apenas o emprego dos controladores não garante um bom amortecimento, fazendo-se necessária uma boa sintonia dos mesmos. A sintonia destes controladores é, na maioria das vezes, feita de forma manual, ou seja, usando o método de tentativa e erro, podendo demandar um tempo relativamente elevado, mesmo que feita por um engenheiro experiente. Para evitar que o projetista dispense tempo procurando uma sintonia adequada para os controladores, métodos automáticos de sintonia vêm sendo estudados. Tais métodos têm como principal vantagem a sintonia dos controladores considerando vários pontos de operação do sistema simultaneamente, fazendo com que o controlador seja robusto para variações em seu ponto de operação nominal. Os métodos automáticos de sintonia utilizam métodos de otimização local ou métodos de otimização global. Os métodos de busca local têm a rapidez como principal vantagem, porém podem não convergir para um valor satisfatório de amortecimento estipulado pelo projetista. Os métodos de busca global, em grande parte das vezes, convergem para um valor de amortecimento solicitado pelo projetista, porém em um tempo elevado. Este trabalho propõe um método de sintonia dos controladores utilizando uma estrutura híbrida, ou seja, algoritmos de busca global juntamente com algoritmos de busca local. Primeiramente uma busca global é feita pelo algoritmo até que um critério de parada, definido pelo projetista, seja alcançado (geralmente um valor de amortecimento mínimo para o sistema). Assim, os parâmetros dos controladores sintonizados pela busca global serão entrada de um método de busca local. O algoritmo de busca local tende a refinar a sintonia dos controladores aumentando, assim, o amortecimento do sistema até um valor especificado pelo projetista. Neste trabalho a busca global é realizada por um algoritmo genético enquanto que a busca local é feita por um algoritmo baseado no gradiente descendente da função objetivo (neste caso o amortecimento). As principais vantagens do algoritmo proposto são a diminuição do tempo de sintonia e o esforço computacional, se comparado a métodos de busca global, verificadas nos resultados do trabalho. / Electric Power Systems are constantly subjected to perturbations, which can be caused for several different reasons, e.g., due to a sudden load increase or a short circuit in a transmission line. These perturbations can induce electromechanical oscillations in the power system, since the angular speed of the generators oscillates. To reduce such oscillations, power system controllers are used, and the most common ones are the PSSs (Power System Stabilizers). In some systems, however, the usage of PSSs is not sufficient to guarantee a satisfactory level for the minimum damping, being necessary the usage of other types of controllers. Hence, FACTS (Flexible Alternating Current Transmission System) controllers, specially the TCSC (Thyristor Controlled Series Capacitor), became an attractive alternative to enhance the damping of electric power systems. The TCSC control action is performed by a POD (Power Oscillation Damper) controller, which is a supplementary control function of the device. However, it is not only the usage of such controllers that guarantees a sufficient damping, but also a good tuning of their parameters. The tuning of such controllers is ordinarily performed manually, using a trial-and-error method, which can last for a long time, even for experienced engineers. To facilitate the designers work in the tuning of the controllers parameters, automatic tuning methods are being studied. Such methods have the main advantage of considering several operating points of the system simultaneously, yielding a robust controller regarding variations in its nominal operating point. The aforementioned automatic tuning methods use local optimization methods or global optimization methods. The local optimization methods have the speed as the main advantage, but they can have convergence issues in the search for the minimum satisfactory damping threshold desired by the designer. The global optimization methods, on the other hand, ordinarily converge for the desired minimum damping threshold, but with large convergence times. This work proposes a controller tuning method using a hybrid structure, i.e., global search methods with local search methods. Initially, a global search is performed by the algorithm until a stop criteria is met, as defined by the designer (usually a minimum damping for the system). Thus, the controller parameters tuned by the global search method are the input values of a local search method. The local search algorithm actually refines the controllers tuning, increasing the system damping to the value defined by the designer. In this work the global search is performed by a genectic algorithm while the local search is performed by an algorithm based in the gradient descent of objective function (damping in this case). The greatest advantages of the proposed algorithm are the possible decrease in computational time and effort, when compared to global search methods, verified in the work results.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-06-26T19:40:40Z No. of bitstreams: 1 MarcosSilvaMontelo.pdf: 2980665 bytes, checksum: 3b07ab02be8c6a4e17cda1a61787ffe2 (MD5) / Made available in DSpace on 2017-06-26T19:40:40Z (GMT). No. of bitstreams: 1 MarcosSilvaMontelo.pdf: 2980665 bytes, checksum: 3b07ab02be8c6a4e17cda1a61787ffe2 (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In this work is investigated the performance of the GMRES Method in studies of power flow extremely loaded, ill-conditioned and including FACTS Controllers, focusing on Jacobian matrix with high numbers of conditioning and real eigenvalue close to zero, in order to consolidate the virtues of GMRES in ill-conditioned problems. From this information you can set operating scenarios that may indicate points of robustness and GMRES efficiency. Consolidating test systems (hypothetical and actual) of difficult convergence associated with extremely high loaded, is also part of research to create s cenarios close to reality, or that may occur in practice. The primary purpose of the inclusion of FACTS is to assess the impact that these devices can cause the Jacobian matrix. These characteristics are informed through eigenvalues and conditioning number. In addition, we propose an iterative solver developed in MATLAB platform for power flow studies and a detailed investigation of the influence of the reordering and the e limination of non-null elements in the quality of the preconditioner of incomplete factors. The proposed methodology was applied to hypothetical and real systems with FACTS controllers, and the results of the experiments showed the greater efficiency of the iterative solver GMRES in most simulations. It was found that the larger the size of the electrical system and the worse their numeric characteristics, the better its performance. / Neste Trabalho é investigado o desempenho do Método GMRES em estudos de Fluxo de potência extremamente carregados, mal condicionados e incluindo Controladores FACTS, enfocando matrizes Jacobianas com elevados números de condicionamento e autovalores reais próximos de zero, a fim de consolidar virtudes do GMRES na solução de problemas mal-condicionados. A apartir destas informações será possível estabelecer cenários de operação que poderão indicar pontos de robustez e eficiência do GMRES. A consolidação de sistemas-teste (hipotéticos e reais) de difícil convergência associados a carregamentos extremamente elevados, também faz parte das investigações para criar cenários próximos da realidade, ou seja, que possam ocorrer na prática. O objetivo primário da inclusão de FACTS está em avaliar o impacto que estes equipamentos podem causar na matriz Jacobiana. Estas características são informadas através de autovalores e número de condicionamento. Além disso, propõe-se um solucionador iterativo desenvolvido na plataforma MATLAB para estudos de fluxo de potência e uma investigação detalhada da influência do reordenamento e da eliminação de elementos não-nulos na qualidade do pré-condicionador de fatores incompletos. A metodologia proposta foi aplicada em sistemas hipotéticos e reais com Controladores FACTS, e os resultados dos experimentos mostraram a maior eficiência do solucionador iterativo GMRES em grande parte das simulações realizadas. Verificou-se que, quanto maior a dimensão do sistema elétrico e quanto pior suas características numéricas, melhor seu desempenho.

While there has been research on development of multiplicative reasoning, and how to teach multiplication facts, there is little research on how children consider they learn these. This study explores the children's learning as they consider how they commit their multiplication facts to memory, discover calculation strategies and develop multiplicative thinking. A group of eleven Year 4 children (8 years old) participated in a series of 13 lessons where they became coresearchers in the exploration of their learning. A contextually based thematic approach was provided through 'Crocodilian Studies'. The mixed-method approach to this study included formal assessment, participant observation, individual interviews, the children's written ideas, and individual case studies. The most significant finding of this study was the powerful influence of peer learning. The children enriched and directed each other's learning as they shared ideas and reflected on their own mathematical learning as they observed and critiqued the thinking of peers. As the children were involved in thinking about how they learn they were able to identify gaps and construct their own learning pathways. A significant finding was that children can develop their multiplicative strategies while they commit their multiplication facts to memory, in a relatively short time provided that the learning process facilitates strategy development and understanding. By exposing the children to multiplication facts in sequenced clusters provided them with a manageable number of facts to be learnt at one time. Another finding related to how children develop calculation strategies through lesson activities rather than being explicitly taught them. The children considered practice important for memorisation. Parental support was significant in enriching the children's learning.

Made available in DSpace on 2016-08-17T14:52:56Z (GMT). No. of bitstreams: 1 Sergio Leon Escalante Cardenas.pdf: 1233424 bytes, checksum: 8be8a81742f69038e591f72b968c13ee (MD5) Previous issue date: 2005-02-28 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work presents the economical and technical aspects of FACTS (flexible ac transmission systems) controllers in steady-state operation of electric power systems (EPS). There Controllers are used in EPS to increase the power transfer limit in the transmission lines and to improve the electromechanical and voltage stability. The models considered in this research are: SVC, TCSC, STATCOM, SSSC and UPFC. The modeling of HVDC link including a commutation capacitor for converter (CCC) is also presented. A Newton-Raphson power flow computer program was implemented in order to assess the steady-state operation of FACTS Controllers. On the other hand, for economic assessment of FACTS application, an optimal power flow (OPF) based on interior point method was implemented and prospectively an OPF using genetic algorithms has been proposed. The studied FACTS Controllers were applied to the IEEE 30 bus and IEEE 118 bus test systems, and a configuration of a real power system regarding to the Brazilian National Interconnected System (SIN) represented with 2256 buses. The analysis of the results obtained from the tests indicates that the operation of a EPS with FACTS is more flexible and presents advantages, such as: lines power transfer increase, possibility of power flow reversal in the lines, a better voltage control in remote buses and operation costs lowering, keeping operation restrictions and fixing both, bus voltages and transmission line power flows. / Neste trabalho são apresentados os aspectos técnicos e econômicos da aplicação dos Controladores FACTS (flexible ac transmission systems) na operação dos sistemas de energia elétrica (SEE) em regime permanente. Os FACTS são utilizados nos SEE para aumentar o limite da transferência de potência nas linhas de transmissão e para melhorar a estabilidade eletromecânica e de tensão. Os modelos dos Controladores FACTS considerados nesta pesquisa são: SVC, TCSC, STATCOM, SSSC e UPFC. Uma modelagem do elo de corrente contínua ou HVDC, inclusive com capacitor de comutação de conversor (CCC) também é apresentada. Para avaliar os aspectos técnicos na operação em regime permanente dos FACTS foi implementado um programa computacional de fluxo de potência baseado no método Newton Raphson. Já para a avaliação econômica da aplicação dos Controladores FACTS foi implementado um fluxo de potência ótimo (FPO) com o método de pontos interiores e prospectivamente foi proposto um FPO adotando algoritmos genéticos. Os Controladores FACTS estudados foram aplicados aos sistemas de teste IEEE de 30 barras, IEEE de 118 barras e uma configuração de um sistema de potência real pertencente ao sistema interligado nacional (SIN) brasileiro representado com 2256 barras. A análise dos resultados obtidos nos testes indica que a operação de um SEE que possui FACTS é mais flexível com vantagens, tais como: aumento da transferência de potência nas linhas, possibilidade de inversão de fluxo de potência nas linhas, um melhor controle de tensão nos barramentos remotos e redução do custo de operação mantendo as restrições de operação impostas e fixando tanto as tensões em barras quanto os fluxos de potência nas linhas.