Impact of a price-maker pumped storage hydro unit on the integration of wind energy in power systems

The increasing integration of larger amounts of wind energy into power systems raises important operational issues, such as the balance between power generation and demand. The pumped storage hydro (PSH) units are one possible solution to mitigate this problem, once they can store the excess of energy in the periods of higher generation and lower demand. However, the behaviour of a PSH unit may differ considerably from the expected in terms of wind power integration when it operates in a liberalized electricity market under a price-maker context. In this regard, this paper models and computes the optimal PSH weekly scheduling in a price-taker and price-maker scenarios, either when the PSH unit operates in standalone and integrated in a portfolio of other generation assets. Results show that the price-maker standalone PSH will integrate less wind power in comparison with the price-taker situation. Moreover, when the PSH unit is integrated in a portfolio with a base load power plant, the role of the price elasticity of demand may completely change the operational profile of the PSH unit. (C) 2014 Elsevier Ltd. All rights reserved.

Spinning reserve and emission unit commitment through stochastic optimization

This paper proposes a stochastic mixed-integer linear approach to deal with a short-term unit commitment problem with uncertainty on a deregulated electricity market that includes day-ahead bidding and bilateral contracts. The proposed approach considers the typically operation constraints on the thermal units and a spinning reserve. The uncertainty is due to the electricity prices, which are modeled by a scenario set, allowing an acceptable computation. Moreover, emission allowances are considered in a manner to allow for the consideration of environmental constraints. A case study to illustrate the usefulness of the proposed approach is presented and an assessment of the cost for the spinning reserve is obtained by a comparison between the situation with and without spinning reserve.

Dynamics of the Dow Jones and the NASDAQ stock indexes

The goal of this study is the analysis of the dynamical properties of financial data series from worldwide stock market indices. We analyze the Dow Jones Industrial Average ( ∧ DJI) and the NASDAQ Composite ( ∧ IXIC) indexes at a daily time horizon. The methods and algorithms that have been explored for description of physical phenomena become an effective background, and even inspiration, for very productive methods used in the analysis of economical data. We start by applying the classical concepts of signal analysis, Fourier transform, and methods of fractional calculus. In a second phase we adopt a pseudo phase plane approach.

Persistence characteristics in financial prices: evidence from the portuguese stock market returns

The objective of this article is to provide additional knowledge to the discussion of long-term memory, leaning over the behavior of the main Portuguese stock index. The first four moments are calculated using time windows of increasing size and sliding time windows of fixed size equal to 50 days and suggest that daily returns are non-ergodic and non-stationary. Seeming that the series is best described by a fractional Brownian motion approach, we use the rescaled-range analysis (R/S) and the detrended fluctuation analysis (DFA). The findings indicate evidence of long term memory in the form of persistence. This evidence of fractal structure suggests that the market is subject to greater predictability and contradicts the efficient market hypothesis in its weak form. This raises issues regarding theoretical modeling of asset pricing. In addition, we carried out a more localized (in time) study to identify the evolution of the degree of long-term dependency over time using windows 200-days and 400-days. The results show a switching feature in the index, from persistent to anti-persistent, quite evident from 2010.

How market power affects the behaviour of a pumped storage hydro unit in the day-ahead electricity market?

The integration of large amounts of wind energy in power systems raises important operation issues such as the balance between power demand and generation. The pumped storage hydro (PSH) units are seen as one solution for this issue, avoiding the need for wind power curtailments. However, the behavior of a PSH unit might differ considerably when it operates in a liberalized market with some degree of market power. In this regard, a new approach for the optimal daily scheduling of a PSH unit in the day-ahead electricity market was developed and presented in this paper, in which the market power is modeled by a residual inverse demand function with a variable elasticity. The results obtained show that increasing degrees of market power of the PSH unit correspond to decreasing levels of storage and, therefore, the capacity to integrate wind power is considerably reduced under these circumstances.

Long-term dependence in financial prices: evidence from the Belgian stock market returns

This article aims to contribute to the discussion of long-term dependence, focusing on the behavior of the main Belgian stock index. Non-parametric analyzes of the general characteristics of temporal frequency show that daily returns are non-ergodic and non-stationary. Therefore, we use the rescaled-range analysis (R/S) and the detrended fluctuation analysis (DFA), under the fractional Brownian motion approach, and we found slight evidence of long-term dependence. These results refute the random walk hypothesis with i.i.d. increments, which is the basis of the EMH in its weak form, and call into question some theoretical modeling of asset pricing. Other more localized complementary study, to identify the evolution of the degree of dependence over time windows, showed that the index has become less persistent from 2010. This may mean a maturing market by the extension of the effects of current financial crisis.

Integração da análise energética na gestão Industrial de uma refinaria de açúcar

Mestrado em Engenharia Química - Optimização Energética na Industria Química

On-line self-healing of circuits implemented on reconfigurable FPGAs

To boost logic density and reduce per unit power consumption SRAM-based FPGAs manufacturers adopted nanometric technologies. However, this technology is highly vulnerable to radiation-induced faults, which affect values stored in memory cells, and to manufacturing imperfections. Fault tolerant implementations, based on Triple Modular Redundancy (TMR) infrastructures, help to keep the correct operation of the circuit. However, TMR is not sufficient to guarantee the safe operation of a circuit. Other issues like module placement, the effects of multi- bit upsets (MBU) or fault accumulation, have also to be addressed. In case of a fault occurrence the correct operation of the affected module must be restored and/or the current state of the circuit coherently re-established. A solution that enables the autonomous restoration of the functional definition of the affected module, avoiding fault accumulation, re-establishing the correct circuit state in real-time, while keeping the normal operation of the circuit, is presented in this paper.

The impact of the 2008 and 2010 financial crises on international stock markets : contagion and long memory

Nesta tese estudamos os efeitos de contágio financeiro e de memória longa causados pelas crises financeiras de 2008 e 2010 em alguns mercados acionistas internacionais. A tese é composta por três ensaios interligados. No Ensaio 1, recorremos à teoria das cópulas para testar a existência de contágio e revelar os canais “investor induced” de transmissão da crise de 2008 aos mercados da Bélgica, França, Holanda e Portugal (grupo NYSE Euronext). Concluímos que existe contágio nestes mercados, que o canal “portfolio rebalancing” é o mecanismo mais importante de transmissão da crise, e que o fenómeno “flight to quality” está presente nos mercados. No Ensaio 2, usando novamente modelos de cópulas, avaliamos os efeitos de contágio provocados pelo mercado acionista grego nos mercados do grupo NYSE Euronext, no contexto da crise de 2010. Os resultados obtidos sugerem que durante a crise de 2010 apenas o mercado português foi objeto de contágio; além disso, conclui-se que os efeitos de contágio provocados pela crise de 2008 são claramente superiores aos efeitos provocados pela crise de 2010. No Ensaio 3, abordamos o tema da memória longa através do estudo do expoente de Hurst dos mercados acionistas da Bélgica, E.U.A., França, Grécia, Holanda, Japão, Reino Unido e Portugal. Verificamos que as propriedades de memória longa dos mercados foram afetadas pelas crises, especialmente a de 2008 – que aumentou a memória longa dos mercados e tornou-os mais persistentes. Finalmente, usando cópulas mais uma vez, verificamos que as crises provocaram, em geral, um aumento na correlação entre os expoentes de Hurst locais dos mercados foco das crises (E.U.A. e Grécia) e os expoentes de Hurst locais dos outros mercados da amostra, sugerindo que o expoente de Hurst pode ser utilizado para detetar efeitos de contágio financeiro. Em síntese, os resultados desta tese sugerem que comparativamente com períodos de acalmia, os períodos de crises financeiras tendem a provocar ineficiência nos mercados acionistas e a conduzi-los na direção da persistência e do contágio financeiro.

Long-term memory in financial prices: evidence from the Dutch stock market returns

Prepared for presentation at the Portuguese Finance Network International Conference 2014, Vilamoura, Portugal, June 18-20

Gestão do stock da bandoteca do centro de processamento de dados do BPA - Banco Português do Atlântico

O programa que nos propusemos fazer destina-se à informatização do stock de bandas da bandoteca do Centro Informático do BPA.

Occupational risk in a glass manufacturing industry unit

Risk assessment is one of the main pillars of the framework directive and other directives in respect of health and safety. It is also the basis of an effective management of safety and health as it is essential to reduce work-related accidents and occupational diseases. To survey the hazards eventually present in the workplaces the usual procedures are i) gathering information about tasks/activities, employees, equipment, legislation and standards; ii) observation of the tasks and; iii) quantification of respective risks through the most adequate risk assessment among the methodologies available. From this preliminary evaluation of a welding plant and, from the different measurable parameters, noise was considered the most critical. This paper focus not only the usual way of risk assessment for noise but also another approach that may allow us to identify the technique with which a weld is being performed.

Gestão de multi-projeto no processo de desenvolvimento de produto

No âmbito da unidade curricular Dissertação/Projeto/Estágio do 2º ano do Mestrado em Engenharia mecânica – Ramo Gestão Industrial do Instituto Superior de Engenharia do Porto, o presente trabalho de dissertação foi enquadrado num projeto de desenvolvimento de ferramentas de apoio à gestão de projetos. O projeto foi desenvolvido no Instituto de Engenharia Mecânica e Gestão Industrial (INEGI) na unidade de Desenvolvimento de Produto e Sistemas (DPS). A realização deste projeto teve como objetivo o desenvolvimento e adequação de ferramentas de apoio à gestão de multi-projeto no processo de desenvolvimento de produto na organização em estudo – o INEGI – DPS. A gestão de projetos tem hoje uma grande importância nos resultados das empresas essencialmente em virtude da necessidade de estas competirem num mundo em grande mudança com concorrentes ferozes, em que a capacidade de responder às mudanças a tempo e de uma forma integrada se torna cada vez mais importante. A atividade levada a cabo pela DPS impõe a necessidade de uma gestão de projetos mais eficaz e eficiente suportada numa gestão de informação centralizada. O presente projeto de investigação teve, numa primeira fase, uma adaptação à organização em estudo. De seguida, foi conduzida uma revisão da literatura com o objetivo de se obter a fundamentação teórica necessária ao desenvolvimento de ferramentas com base nas metodologias lean. Prosseguiu com o levantamento da situação inicial da organização e com a identificação dos problemas existentes na gestão de projetos. Incluiu também uma revisão e análise das ferramentas existentes na unidade em estudo. Este conhecimento permitiu delinear uma visão para guiar o desenvolvimento das ferramentas. Após a definição da visão foi, então, realizado o desenvolvimento das ferramentas de auxílio à gestão multi-projeto na organização. A concretização deste trabalho resultou no desenvolvimento de três ferramentas de auxílio à gestão multi-projeto na unidade. Estas ferramentas tornam o processo de gestão de projetos mais simples e fácil de assimilar, requerendo apenas alguns inputs por parte dos colaboradores. Estas ferramentas estão apoiadas nos pilares do lean, e deste modo estão vocacionadas para reduzir o desperdício, promover a melhoria contínua, aumentar o desempenho global dos vários atores nos projetos de modo a entregar mais valor e qualidade superior com menores custos. Acima de tudo, valorizar o trabalho dos colaboradores, tornando-os mais eficientes, eficazes, motivados e comprometidos com a organização.

Legionnaires' disease in the renal transplant unit of "Hospital das Clinicas, FMUSP": during a five year period (1988-1993)

Several reports have related Legionella pneumophila with pneumonia in renal transplant patients, however this association has not been systematically documented in Brazil. Therefore this paper reports the incidence, by serologycal assays, of Legionella pneumophila serogroup 1 in these patients during a five year period. For this purpose sera from blood samples of 70 hospitalized patients with pneumonia from the Renal Transplant Unit of Hospital das Clinicas, FMUSP collected at the acute and convalescent phase of infection were submitted to indirect immunofluorescence assay (IFA) to demonstrate anti-Legionella pneumophila serogroup 1 antibodies. Of these 70 patients studied during the period of 1988 to 1993,18 (25.71 %) had significant rises in specific antibody titers for Legionella pneumophila serogroup 1. Incidence was interrupted following Hospital water decontamination procedures, with recurrence of infections after treatment interruption. In this study, the high susceptibility (25.71%) of immunodepressed renal transplant patients to Legionella pneumophila serogroup 1 nosocomial infections is documented. The importance of the implementation and maintenance of water decontamination measures for prophylaxis of the infection is also clearly evident.

Congenital cytomegalovirus infection in a neonatal intensive care unit in Brazil evaluated by PCR and association with perinatal aspects

Cytomegalovirus (CMV) infection is the most common congenital infection, affecting 0.4% to 2.3% newborns. Most of them are asymptomatic at birth, but later 10% develop handicaps, mainly neurological disturbances. Our aim was to determine the prevalence of CMV shed in urine of newborns from a neonatal intensive care unit using the polymerase chain reaction (PCR) and correlate positive cases to some perinatal aspects. Urine samples obtained at first week of life were processed according to a PCR protocol. Perinatal data were collected retrospectively from medical records. Twenty of the 292 cases (6.8%) were CMV-DNA positive. There was no statistical difference between newborns with and without CMV congenital infection concerning birth weight (p=0.11), gestational age (p=0.11), Apgar scores in the first and fifth minutes of life (p=0.99 and 0.16), mother's age (p=0.67) and gestational history. Moreover, CMV congenital infection was neither related to gender (p=0.55) nor to low weight (<2,500g) at birth (p=0.13). This high prevalence of CMV congenital infection (6.8%) could be due to the high sensitivity of PCR technique, the low socioeconomic level of studied population or the severe clinical status of these newborns.