924 resultados para Convergence insufficiency


Relevância:

10.00% 10.00%

Publicador:

Resumo:

In Permanent Transit: Discourses and Maps of the Intercultural Experience builds interdisciplinary approaches to the study of migrations, traffics, globalization, communication, regulations, arts, literature, and other intercultural processes, in the context of past and present times. The book offers a convergence of perspectives, combining conceptual and empirical work by sociologists, anthropologists, historians, linguists, educators, lawyers, media, specialists, and literary studies writers, in their shared attempt to understand the many routes of the intercultural experience. In Permanent Transit: Discourses and Maps of the Intercultural Experience builds interdisciplinary approaches to the study of migrations, traffics, globalization, communication, regulations, arts, literature, and other intercultural processes, in the context of past and present times. The book offers a convergence of perspectives, combining conceptual and empirical work by sociologists, anthropologists, historians, linguists, educators, lawyers, media, specialists, and literary studies writers, in their shared attempt to understand the many routes of the intercultural experience.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Electricity markets are complex environments, involving a large number of different entities, playing in a dynamic scene to obtain the best advantages and profits. MASCEM is a multi-agent electricity market simulator to model market players and simulate their operation in the market. Market players are entities with specific characteristics and objectives, making their decisions and interacting with other players. MASCEM is integrated with ALBidS, a system that provides several dynamic strategies for agents’ behavior. This paper presents a method that aims at enhancing ALBidS competence in endowing market players with adequate strategic bidding capabilities, allowing them to obtain the higher possible gains out of the market. This method uses a reinforcement learning algorithm to learn from experience how to choose the best from a set of possible actions. These actions are defined accordingly to the most probable points of bidding success. With the purpose of accelerating the convergence process, a simulated annealing based algorithm is included.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In competitive electricity markets with deep concerns for the efficiency level, demand response programs gain considerable significance. As demand response levels have decreased after the introduction of competition in the power industry, new approaches are required to take full advantage of demand response opportunities. Grid operators and utilities are taking new initiatives, recognizing the value of demand response for grid reliability and for the enhancement of organized spot markets’ efficiency. This paper proposes a methodology for the selection of the consumers that participate in an event, which is the responsibility of the Portuguese transmission network operator. The proposed method is intended to be applied in the interruptibility service implemented in Portugal, in convergence with Spain, in the context of the Iberian electricity market. This method is based on the calculation of locational marginal prices (LMP) which are used to support the decision concerning the consumers to be schedule for participation. The proposed method has been computationally implemented and its application is illustrated in this paper using a 937 bus distribution network with more than 20,000 consumers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper proposes a computationally efficient methodology for the optimal location and sizing of static and switched shunt capacitors in large distribution systems. The problem is formulated as the maximization of the savings produced by the reduction in energy losses and the avoided costs due to investment deferral in the expansion of the network. The proposed method selects the nodes to be compensated, as well as the optimal capacitor ratings and their operational characteristics, i.e. fixed or switched. After an appropriate linearization, the optimization problem was formulated as a large-scale mixed-integer linear problem, suitable for being solved by means of a widespread commercial package. Results of the proposed optimizing method are compared with another recent methodology reported in the literature using two test cases: a 15-bus and a 33-bus distribution network. For the both cases tested, the proposed methodology delivers better solutions indicated by higher loss savings, which are achieved with lower amounts of capacitive compensation. The proposed method has also been applied for compensating to an actual large distribution network served by AES-Venezuela in the metropolitan area of Caracas. A convergence time of about 4 seconds after 22298 iterations demonstrates the ability of the proposed methodology for efficiently handling large-scale compensation problems.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper is about PCMAT, an adaptive learning platform for Mathematics in Basic Education schools. Based on a constructivist approach, PCMAT aims at verifying how techniques from adaptive hypermedia systems can improve e-learning based systems. To achieve this goal, PCMAT includes a Pedagogical Model that contains a set of adaptation rules that influence the student-platform interaction. PCMAT was subject to a preliminary testing with students aged between 12 and 14 years old on the subject of direct proportionality. The results from this preliminary test are quite promising as they seem to demonstrate the validity of our proposal.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Gulf of Cadiz, as part of the Azores-Gibraltar plate boundary, is recognized as a potential source of big earthquakes and tsunamis that may affect the bordering countries, as occurred on 1 November 1755. Preparing for the future, Portugal is establishing a national tsunami warning system in which the threat caused by any large-magnitude earthquake in the area is estimated from a comprehensive database of scenarios. In this paper we summarize the knowledge about the active tectonics in the Gulf of Cadiz and integrate the available seismological information in order to propose the generation model of destructive tsunamis to be applied in tsunami warnings. The fault model derived is then used to estimate the recurrence of large earthquakes using the fault slip rates obtained by Cunha et al. (2012) from thin-sheet neotectonic modelling. Finally we evaluate the consistency of seismicity rates derived from historical and instrumental catalogues with the convergence rates between Eurasia and Nubia given by plate kinematic models.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The paper focuses on the importance of Darwin’s work for the shaping of Henri Bergson’s philosophy, bearing on mind that the two authors first intercepted symbolically in 1859, when On the Origin of Species was published and Bergson was born. Bergson studied the biological sciences of his time, whose results were integrated in a metaphysical thought. He belonged to spiritualistic positivism, a philosophy that goes from the positive data of sciences and finds the ultimate explanation of reality in a spiritual principle. He was interested in the positive evolution of the natural world and in the works of naturalists such as Lamarck, De Vries or Eimer. Darwin was among these authors, being responsible for a vision of evolution that went from the scientific level to other domains. Bergson defends the “insufficiency of pure Darwinism” by pointing out the necessity to compensate scientific evolution with an internal metaphysical reading of the real, which he considered to be “true evolutionism”. This criticism is the most visible aspect of the relations between both works. However, an attentive look verifies that Darwin’s influence overcomes the divergence of positions concerning the extent of “evolution”. The French philosopher knew not only the 1859’s bestseller, but also studies by Darwin about ethology, entomology and botany, which contributed to the fact that the naturalist’s impact gained fundamental importance in Bergson’s philosophical perspective.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper describes an implementation of a long distance echo canceller, operating on full-duplex with hands-free and in real-time with a single Digital Signal Processor (DSP). The proposed solution is based on short length adaptive filters centered on the positions of the most significant echoes, which are tracked by time delay estimators, for which we use a new approach. To deal with double talking situations a speech detector is employed. The floating-point DSP TMS320C6713 from Texas Instruments is used with software written in C++, with compiler optimizations for fast execution. The resulting algorithm enables long distance echo cancellation with low computational requirements, suited for embbeded systems. It reaches greater echo return loss enhancement and shows faster convergence speed when compared to the conventional approach. The experimental results approach the CCITT G.165 recommendation levels.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Audiovisual e Multimédia.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Trabalho de projeto apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Jornalismo.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertação de Mestrado, Ciências Biomédicas, 14 de Outubro de 2015, Universidade dos Açores.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dissertação de Mestrado, Ciências Económicas e Empresariais, 28 de Julho de 2015, Universidade dos Açores.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Mestrado em Contabilidade