449 research outputs found
Electricity Price Forecasting by Averaging Dynamic Factor Models
In the context of the liberalization of electricity markets, forecasting prices is essential. With this aim, research has evolved to model the particularities of electricity prices. In particular, dynamic factor models have been quite successful in the task, both in the short and long run. However, specifying a single model for the unobserved factors is difficult, and it cannot be guaranteed that such a model exists. In this paper, model averaging is employed to overcome this difficulty, with the expectation that electricity prices would be better forecast by a combination of models for the factors than by a single model. Although our procedure is applicable in other markets, it is illustrated with an application to forecasting spot prices of the Iberian Market, MIBEL (The Iberian Electricity Market). Three combinations of forecasts are successful in providing improved results for alternative forecasting horizons
Electricity Price Forecasting by Averaging Dynamic Factor Models
In the context of the liberalization of electricity markets, forecasting prices is essential. With this aim, research has evolved to model the particularities of electricity prices. In particular, dynamic factor models have been quite successful in the task, both in the short and long run. However, specifying a single model for the unobserved factors is difficult, and it cannot be guaranteed that such a model exists. In this paper, model averaging is employed to overcome this difficulty, with the expectation that electricity prices would be better forecast by a combination of models for the factors than by a single model. Although our procedure is applicable in other markets, it is illustrated with an application to forecasting spot prices of the Iberian Market, MIBEL (The Iberian Electricity Market). Three combinations of forecasts are successful in providing improved results for alternative forecasting horizons
Recomendaciones de dieta y ejercicio en niños y adolescentes
Los niños constituyen uno de los grupos vulnerables en el ámbito de la nutrición, el instaurar hábitos saludables de dieta y ejercicio durante la infancia conduciría a la prevención de muchas enfermedades crónicas (diabetes tipo II, hipertensión y obesidad entre otras), cada vez más frecuentes y de más temprana aparición en países desarrollados. Por otra parte, la actividad física habitual produce una sensación de bienestar general relacionada con la mejora dela auto-estima, entre sus efectos psicológicos positivos se encuentra un efecto antidepresivo y una mejora del control de la ansiedad y del stress. Por todos estos motivos, durante la infancia y la adolescencia se recomiendan programas de actividad física ya que éstos, se han asociado con beneficios de tipo fisiológico, sociológico y psicológico tanto a corto como a largo plazo
Análisis de la red social Facebook como herramienta para construir la identidad corporativa de una institución educativa inicial - privada
Este proyecto de investigación analiza la efectividad de la popular red social Facebook como herramienta útil para el relanzamiento de una marca y la creación de identidad corporativa de la misma. Para ello, se ha empezado investigando las teorías relacionadas a la comunicación corporativa, imagen empresarial y el uso de las nuevas tecnologías como medio de interacción, hasta el empleo de las “Social ADS”, que son estrategias de promoción pagadas mediante las redes sociales como Facebook, Instagram, Twitter, entre otras que, cada día cuentan con mayor cantidad de usuarios, llegando a estimarse que de cada diez personas que usan internet, ocho tienen un perfil en alguna red social, y se conectan desde cualquier lugar, usando sus computadoras, notebooks, smartphones, tabletas, entre otros dispositivos. Estas personas, a su vez son los clientes potenciales o conforman el público objetivo de diversas empresas. Teniendo en cuenta esto, se ha diseñado un plan de construcción de identidad corporativa y relanzamiento de marca a través de la red social Facebook, para la Institución Educativa Inicial “Anidar”, que está ubicada en la Av. Arnaldo Marquez 1704, en el distrito de Jesús María, en la ciudad de Lima, con el objetivo de incrementar la valoración de la marca y la contratación de los servicios que ella brinda. La Institución “Anidar” ofrece servicios de guardería, preescolar, nido y taller de acompañamiento temprano con padres de familia.Trabajo de suficiencia profesionalCampus Lima Centr
Extraction of ferulic acid and feruloylated arabinoxylo-oligosaccharides from wheat bran using pressurized hot water
Producción CientíficaPressurized water was tested as solvent for the hydrolysis and extraction of Ferulic acid (FA) and feruloylated arabinoxylooligosaccharides (F-AXOS) from destarched wheat bran (DWB). Results were dependent on the severity factor of the process (combination of temperature and time), obtaining the maximum extraction yields at 200°C and 3.5 min. 78% of the total FA was successfully extracted, being 17% in its free form and the rest, covalent ester-bounded to arabinoxylans. Under such conditions, 80% of the arabinoxylans are extracted with a degree of FA esterification of 1.34 g FA/100 g AXOS, and an average molecular weight of 1,3·104 Da. Pressurized Microwave Assisted Extraction was also studied to evaluate potential intensification of the process using microwaves. However, no significant differences were observed with the microwave heating. Residual solid after extraction was mainly composed by lignin and cellulose (56% and 21%, respectively) showing that hot compressed water technology can be integrated in the first steps of a biorefinery for the total valorization of the wheat bran.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project CTQ2015-64892-R
Numerical simulation of wind waves on the Río de la Plata: evaluation of four global atmospheric databases
The performance of NCEP/NCAR I, NCEP/DOE II, JRA-25 and ERA-Interim global databases, implemented as atmospheric forcings of the SWAN model in the Río de la Plata region, was quantitatively tested by calculating the bias, the mean square root error, the determination coefficient and the slope of the line fitted between observed and simulated wave parameters (significant wave height, mean period and direction). Even though statistical estimators showed no evident differences for wave periods and directions some noticeable differences were observed for simulated significant wave heights depending on the forcing used. The lowest bias (0.22 m) was obtained when the SWAN model was forced by ERA-Interim. With regard to the mean square root errors, the lowest values were obtained when NCEP/NCAR I (0.16 m) and NCEP/DOE II (0.19 m) were used as forcing. In addition, the best slope for simulated heights (0.79) was obtained using NCEP/DOE II. Computed determination coefficients for heights, periods and directions were very similar (0.89-0.93) for all the simulations carried out in this study. Energetic and severe wave events were given special consideration. The most energetic wave episode recorded in the Río de la Plata mouth (24 August, 2005) was analyzed and discussed in particular. It was concluded that during energetic atmospheric conditions the best agreement is achieved by implementing NCEP/DOE II as forcing. In the light of these results it is concluded that NCEP/DOE II is the most suitable atmospheric forcing to simulate wave heights with the SWAN model in the Río de la Plata region.Na região do Rio de la Plata, o desempenho das reanálises globais do NCEP/NCAR I, NCEP/DOE II, JRA-25 e ERAInterim implementadas como forçantes atmosféricas do modelo SWAN foram quantitativamente acessados através do viés, erro quadrático médio, coeficiente de determinação e inclinação da reta. Estes índices foram obtidos dos parâmetros de ondas observados e simulados (alturas significativas de ondas, período principal e direção). Embora as estimativas estatísticas não mostrem diferenças evidentes para períodos e direções, algumas diferenças notáveis foram obtidas para altura de ondas simuladas, dependendo do vento utilizado. O menor viés para altura significativa (0.22 m) foi obtido quando o SWAM foi forçado com a ERAInterim, enquanto o NCEP/NCAR I (0.16 m) e NCEP/DOE II (0.19 m) forneceram menor erro quadrático médio. A melhor inclinação da reta entre simulação e observação de altura significativa (0.79) foi obtida usando NCEP/DOE II. No período de estudo, o maior episódio de onda registrado na boca do Río de la Plata foi analisado e discutido. Neste evento de condições atmosféricas energéticas o melhor ajuste foi alcançado utilizando os ventos do NCEP/DOE II como forçante. Conclui-se que a base de dados NCEP/DOE II é forçante atmosférica mais adequada para simular alturas significativas de ondas com o modelo SWAN na região estudada
Coordinated management of low voltage power networks with photovoltaic energy sources
Over the last decades, active power networks have reached great attention due to the incorporation of distributed energy resources into low voltage power systems. In this paper, a decentralized energy management strategy is proposed as an efficient way to minimize both active power losses and voltage profile deviation of an distribution power network with photovoltaic solar farms, and also at the same time, aims to improve the reliability and the security of supply. The coordinated energy management concept relies on a two-step optimization approach based on genetic algorithms (GA) and MINLP, in which a multi-objective function is used which takes into account reliability and operational technical constraints in its formulation. The suitability of the proposed methodology is tested on an existing low voltage power system, in which two aspects are considered: firstly, determining the optimal allocation of PV units and secondly, establishing the optimal reschedule of the active power of the generation units partic ipating in the energy mix and minimizing both the real power losses and voltage deviation of the entire power system.This work has been partly funded by the European Union seventh framework program FP7-SMARTCITIES-2013 under grant agreement 608860 IDE4L – Ideal grid for all
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