828 resultados para Distributed parameter


Relevância:

20.00% 20.00%

Publicador:

Resumo:

XXXIII Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos (SBRC 2015), III Workshop de Comunicação em Sistemas Embarcados Críticos. Vitória, Brasil.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

INTRODUCTION: A growing body of evidence shows the prognostic value of oxygen uptake efficiency slope (OUES), a cardiopulmonary exercise test (CPET) parameter derived from the logarithmic relationship between O(2) consumption (VO(2)) and minute ventilation (VE) in patients with chronic heart failure (CHF). OBJECTIVE: To evaluate the prognostic value of a new CPET parameter - peak oxygen uptake efficiency (POUE) - and to compare it with OUES in patients with CHF. METHODS: We prospectively studied 206 consecutive patients with stable CHF due to dilated cardiomyopathy - 153 male, aged 53.3±13.0 years, 35.4% of ischemic etiology, left ventricular ejection fraction 27.7±8.0%, 81.1% in sinus rhythm, 97.1% receiving ACE-Is or ARBs, 78.2% beta-blockers and 60.2% spironolactone - who performed a first maximal symptom-limited treadmill CPET, using the modified Bruce protocol. In 33% of patients an cardioverter-defibrillator (ICD) or cardiac resynchronization therapy device (CRT-D) was implanted during follow-up. Peak VO(2), percentage of predicted peak VO(2), VE/VCO(2) slope, OUES and POUE were analyzed. OUES was calculated using the formula VO(2) (l/min) = OUES (log(10)VE) + b. POUE was calculated as pVO(2) (l/min) / log(10)peakVE (l/min). Correlation coefficients between the studied parameters were obtained. The prognosis of each variable adjusted for age was evaluated through Cox proportional hazard models and R2 percent (R2%) and V index (V6) were used as measures of the predictive accuracy of events of each of these variables. Receiver operating characteristic (ROC) curves from logistic regression models were used to determine the cut-offs for OUES and POUE. RESULTS: pVO(2): 20.5±5.9; percentage of predicted peak VO(2): 68.6±18.2; VE/VCO(2) slope: 30.6±8.3; OUES: 1.85±0.61; POUE: 0.88±0.27. During a mean follow-up of 33.1±14.8 months, 45 (21.8%) patients died, 10 (4.9%) underwent urgent heart transplantation and in three patients (1.5%) a left ventricular assist device was implanted. All variables proved to be independent predictors of this combined event; however, VE/VCO2 slope was most strongly associated with events (HR 11.14). In this population, POUE was associated with a higher risk of events than OUES (HR 9.61 vs. 7.01), and was also a better predictor of events (R2: 28.91 vs. 22.37). CONCLUSION: POUE was more strongly associated with death, urgent heart transplantation and implantation of a left ventricular assist device and proved to be a better predictor of events than OUES. These results suggest that this new parameter can increase the prognostic value of CPET in patients with CHF.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Further improvements in demand response programs implementation are needed in order to take full advantage of this resource, namely for the participation in energy and reserve market products, requiring adequate aggregation and remuneration of small size resources. The present paper focuses on SPIDER, a demand response simulation that has been improved in order to simulate demand response, including realistic power system simulation. For illustration of the simulator’s capabilities, the present paper is proposes a methodology focusing on the aggregation of consumers and generators, providing adequate tolls for the demand response program’s adoption by evolved players. The methodology proposed in the present paper focuses on a Virtual Power Player that manages and aggregates the available demand response and distributed generation resources in order to satisfy the required electrical energy demand and reserve. The aggregation of resources is addressed by the use of clustering algorithms, and operation costs for the VPP are minimized. The presented case study is based on a set of 32 consumers and 66 distributed generation units, running on 180 distinct operation scenarios.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The high penetration of distributed energy resources (DER) in distribution networks and the competitive environment of electricity markets impose the use of new approaches in several domains. The network cost allocation, traditionally used in transmission networks, should be adapted and used in the distribution networks considering the specifications of the connected resources. The main goal is to develop a fairer methodology trying to distribute the distribution network use costs to all players which are using the network in each period. In this paper, a model considering different type of costs (fixed, losses, and congestion costs) is proposed comprising the use of a large set of DER, namely distributed generation (DG), demand response (DR) of direct load control type, energy storage systems (ESS), and electric vehicles with capability of discharging energy to the network, which is known as vehicle-to-grid (V2G). The proposed model includes three distinct phases of operation. The first phase of the model consists in an economic dispatch based on an AC optimal power flow (AC-OPF); in the second phase Kirschen's and Bialek's tracing algorithms are used and compared to evaluate the impact of each resource in the network. Finally, the MW-mile method is used in the third phase of the proposed model. A distribution network of 33 buses with large penetration of DER is used to illustrate the application of the proposed model.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias cells) required to model them. Primary bipedal gaits (e.g., walk, run) are characterized by dihedral symmetry, whereas secondary bipedal gaits (e.g., gallop-walk, gallop- run) are characterized by a lower, cyclic symmetry. This fact has been used in tests of human odometry (e.g., Turvey et al. in P Roy Soc Lond B Biol 276:4309–4314, 2009, J Exp Psychol Hum Percept Perform 38:1014–1025, 2012). Results suggest that when distance is measured and reported by gaits from the same symmetry class, primary and secondary gaits are comparable. Switching symmetry classes at report compresses (primary to secondary) or inflates (secondary to primary) measured distance, with the compression and inflation equal in magnitude. The present research (a) extends these findings from overground locomotion to treadmill locomotion and (b) assesses a dynamics of sequentially coupled measure and report phases, with relative velocity as an order parameter, or equilibrium state, and difference in symmetry class as an imperfection parameter, or detuning, of those dynamics. The results suggest that the symmetries and dynamics of distance measurement by the human odometer are the same whether the odometer is in motion relative to a stationary ground or stationary relative to a moving ground.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nos últimos anos o aumento exponencial da utilização de dispositivos móveis e serviços disponibilizados na “Cloud” levou a que a forma como os sistemas são desenhados e implementados mudasse, numa perspectiva de tentar alcançar requisitos que até então não eram essenciais. Analisando esta evolução, com o enorme aumento dos dispositivos móveis, como os “smartphones” e “tablets” fez com que o desenho e implementação de sistemas distribuidos fossem ainda mais importantes nesta área, na tentativa de promover sistemas e aplicações que fossem mais flexíveis, robutos, escaláveis e acima de tudo interoperáveis. A menor capacidade de processamento ou armazenamento destes dispositivos tornou essencial o aparecimento e crescimento de tecnologias que prometem solucionar muitos dos problemas identificados. O aparecimento do conceito de Middleware visa solucionar estas lacunas nos sistemas distribuidos mais evoluídos, promovendo uma solução a nível de organização e desenho da arquitetura dos sistemas, ao memo tempo que fornece comunicações extremamente rápidas, seguras e de confiança. Uma arquitetura baseada em Middleware visa dotar os sistemas de um canal de comunicação que fornece uma forte interoperabilidade, escalabilidade, e segurança na troca de mensagens, entre outras vantagens. Nesta tese vários tipos e exemplos de sistemas distribuídos e são descritos e analisados, assim como uma descrição em detalhe de três protocolos (XMPP, AMQP e DDS) de comunicação, sendo dois deles (XMPP e AMQP) utilzados em projecto reais que serão descritos ao longo desta tese. O principal objetivo da escrita desta tese é demonstrar o estudo e o levantamento do estado da arte relativamente ao conceito de Middleware aplicado a sistemas distribuídos de larga escala, provando que a utilização de um Middleware pode facilitar e agilizar o desenho e desenvolvimento de um sistema distribuído e traz enormes vantagens num futuro próximo.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ligand K-edge XAS of an [Fe3S4]0 model complex is reported. The pre-edge can be resolved into contributions from the í2Ssulfide, í3Ssulfide, and Sthiolate ligands. The average ligand-metal bond covalencies obtained from these pre-edges are further distributed between Fe3+ and Fe2.5+ components using DFT calculations. The bridging ligand covalency in the [Fe2S2]+ subsite of the [Fe3S4]0 cluster is found to be significantly lower than its value in a reduced [Fe2S2] cluster (38% vs 61%, respectively). This lowered bridging ligand covalency reduces the superexchange coupling parameter J relative to its value in a reduced [Fe2S2]+ site (-146 cm-1 vs -360 cm-1, respectively). This decrease in J, along with estimates of the double exchange parameter B and vibronic coupling parameter ì2/k-, leads to an S ) 2 delocalized ground state in the [Fe3S4]0 cluster. The S K-edge XAS of the protein ferredoxin II (Fd II) from the D. gigas active site shows a decrease in covalency compared to the model complex, in the same oxidation state, which correlates with the number of H-bonding interactions to specific sulfur ligands present in the active site. The changes in ligand-metal bond covalencies upon redox compared with DFT calculations indicate that the redox reaction involves a two-electron change (one-electron ionization plus a spin change of a second electron) with significant electronic relaxation. The presence of the redox inactive Fe3+ center is found to decrease the barrier of the redox process in the [Fe3S4] cluster due to its strong antiferromagnetic coupling with the redox active Fe2S2 subsite.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Relevância:

20.00% 20.00%

Publicador:

Resumo:

RESUMO: A Diabetes Mellitus é uma doença metabólica crónica, com deficiência a nível do metabolismo dos hidratos de carbono, lípidos e proteínas, resultante de deficiências na secreção ou ação da insulina, ou de ambas, que quando não tratada antecipadamente e de modo conveniente, pode ter consequências muito graves. Dado a incidência a nível mundial da Diabetes Mellitus, torna-se de elevada importância avaliar toda a sua envolvência e estudar bem quais os critérios a ter em consideração. Este trabalho propõe-se estudar para além dos parâmetros bioquímicos relacionados com a doença - Glicose e Hemoglobina Glicada A1c (HbA1c), analisar os resultados dos últimos cinco anos (2008-2012) dos ensaios interlaboratoriais do PNAEQ, do Departamento de Epidemiologia, do Instituto Nacional de Saúde Dr. Ricardo Jorge. Foram também analisadas as metodologias utilizadas e as variações interlaboratoriais, de forma a entender qual ou quais são os parâmetros mais adequados para o seu diagnóstico e controlo. Este estudo utilizou a população de laboratórios portugueses, públicos e privados, de Portugal Continental e Ilhas, um laboratório de Angola e outro de Macau que se inscreveram no PNAEQ nestes cinco anos, sendo a amostra composta pelo n.º de participações. No programa de Química Clinica foram distribuídas 38 amostras e no programa de HbA1c foram distribuídas 22 amostras. Para a glicose, o nível de desempenho nos ensaios é na globalidade das amostras de Excelente, no entanto verifica-se que sempre que a concentração da amostra é de nível patológico, que a maioria dos ensaios o desempenho foi inferior – Bom. O método de eleição e com CV% mais baixos foi o método da hexoquinase. Para a HbA1c, o nível de desempenho nos ensaios é na globalidade das amostras de Excelente. O método de eleição e com CV% mais baixos foi o método de HPLC. O CV% para a glicose ronda desde 2010 a 2012, os 3% e para a HbA1c foi de aproximadamente 4,0% em 2012. A HbA1c tem mostrado ser uma ferramenta muito útil, importante e robusta na monitorização da Diabetes, sendo hoje em dia quase sempre requisitada em análises de rotina a diabéticos de modo a prevenir complicações que possam vir a acorrer. No futuro poderá ser um importante, senão o parâmetro de futuro, para o diagnóstico da Diabetes, no entanto, mesmo já tendo sido muito trabalhada a sua padronização, ainda existem questões por responder como quais são na realidade todos os seus interferentes, qual a verdadeira relação da HbA1c com a glicose média estimada, em todas as populações e com estudos epidemiológicos. Também a própria educação do diabético e clínico deve ser aprimorada, pelo que neste momento as PTGO e os doseamentos de glicose em jejum devem ser utilizados e encontrando-se a Norma da DGS N.º 033/2011 de acordo com as necessidades e com o estado da arte deste parâmetro. A implementação da glicose média estimada será uma mais-valia na monitorização dos diabéticos pelo que deverá ser uma das prioridades a ter em conta no futuro desta padronização, uniformizando a decisão clinica baseada nela e minimizando a dificuldade de interpretação de resultados de laboratório para laboratório. --------------ABSTRACT: Diabetes Mellitus is a chronic metabolic disease, with a deficit in the metabolism of carbohydrates, lipids and proteins, resulting from deficiencies in insulin secretion or action, or both, which if, when not early treated in a proper way, may result in very serious consequences. Given the worldwide incidence of diabetes mellitus, it is highly important to evaluate all its background and study specifically all the criteria to take into consideration. The aim of this thesis is to study and evaluate beyond the biochemical parameters related to the disease - Glucose and Glycated Haemoglobin A1c (HbA1c), analyze the results of the last five years (2008-2012) of the PNAEQ interlaboratorial tests, in the Department of Epidemiology of National Institute of Health Dr. Ricardo Jorge. It is also intended to analyze the methodologies used and the interlaboratorial variations, in order to understand the most suitable parameters for the diagnosis and control. This study was based in a population of Portuguese laboratories, public and private, of Portugal mainland and islands, a laboratory of Angola and other from Macau, who enrolled in PNAEQ in these five years, and the sample was composed by the n. º of holdings. In the Clinical Chemistry Program there were distributed 38 samples and in the program HbA1c were distributed 22 samples. For glucose, the level of performance in the total nº of the samples was Excellent; however, it was found that when the concentration level of the sample was pathological, in most of the tests the performance was Good. The most preferred method with the lowest CV% is the hexokinase method. For the HbA1c, as a whole, the samples’ tests were Excellent, at the level of performance. The method of election with the lower CV% was the HPLC. The CV% for glucose was around 3%, from 2010 to 2012 and the HbA1c was approximately 4.0% in 2012. The HbA1c method has demonstrated to be a very useful tool, important and robust for monitoring diabetes, being nowadays, almost always required in routine analysis to prevent future complications. In the future it may be an important parameter, if not the most important, for the diagnosis of diabetes. However, despite it has already been standardized, there are still some questions that need to be answered, such as, which are in fact all their interferences, which is the true connection of HbA1c, when compared with the estimated average glucose, in all populations and epidemiological studies. Moreover, the education of the patient and the doctor concerning diabetes should be improved. Nowadays, the Oral Glucose Tolerance Test (OGTT) and fasting glucose determinations should be used and, the needs and the state of the art of this parameter, should be in accordance with the Standard DGS N. º 033/2011. The Implementation of the estimated average glucose will be an added value in monitoring diabetics and, therefore, should be a priority to consider in its future standardization and clinical decision based on it, will be uniform and the difficulty of interpreting results from laboratory to laboratory will be minimal.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dissertação para obtenção do Grau de Doutora em Estatística e Gestão de Risco, Especialidade em Estatística

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis submitted in fulfilment of the requirements for the Degree of Master of Science in Computer Science