Comparing univariate and multivariate models to forecast portfolio Value-at-Risk

This article compares multivariate and univariate Generalized Autoregressive Conditional Heteroskedasticity (GARCH) models to forecast portfolio value-at-risk (VaR). We provide a comprehensive look at the problem by considering realistic models and diversified portfolios containing a large number of assets, using both simulated and real data. Moreover, we rank the models by implementing statistical tests of comparative predictive ability. We conclude that multivariate models ou tperform their univariate counterparts on an out-of-sample basis. In particular, among the models considered in this article, the dynamic conditional correlation model with Student's t errors seems to be the most appropriate specification when implemented to estimate the VaR of the real portfolios analyzedA. A. P. S. acknowledges financial support from research Projects CNPq Universal 481719/2011-3 and UFSC-Funpesquisa 2010/2011 from the Brazilian Government. F. J. N. is supported by the Spanish Government through Project MTM2010-16519. E. R. is supported by the Spanish Government ECO2009-0810

Recent Contributions of Elastin-Like Recombinamers to Biomedicine and Nanotechnology

Abstract: The emergence of the new scientific field known as nanomedicine is being catalyzed by multiple improvements in nanoscience techniques and significant progress in materials science, especially as regards the testing of novel and sophisticated biomaterials. This conjuncture has furthered the development of promising instruments in terms of detection, bioanalysis, therapy, diagnostics and imaging. Some of the most innovative new biomaterials are protein-inspired biomimetic materials in which modern biotechnology and genetic-engineering techniques complement the huge amount of information afforded by natural protein evolution to create advanced and tailor-made multifunctional molecules. Amongst these protein-based biomaterials, Elastin-like Recombinamers (ELRs) have demonstrated their enormous potential in the fields of biomedicine and nanoscience in the last few years. This broad applicability derives from their unmatched properties, particularly their recombinant and tailor-made nature, the intrinsic characteristics derived from their elastin-based origin (mainly their mechanical properties and ability to self-assemble as a result of their stimuli-responsive behavior), their proven biocompatibility and biodegradability, as well as their versatility as regards incorporating advanced chemical or recombinant modifications into the original structure that open up an almost unlimited number of multifunctional possibilities in this developing field. This article provides an updated review of the recent challenges overcome by using these recombinant biomaterials in the fields of nano- and biomedicine, ranging from nanoscale applications in surface modifications and self-assembled nanostructures to drug delivery and regenerative medicine.Este trabajo forma parte de Proyectos de Investigación financiados por la Comisión Europea a través del Fondo Europeo de Desarrollo Regional (ERDF), por el del MINECO (MAT2010-15982, MAT2010-15310, PRI-PIBAR-2011-1403 and MAT2012-38043), la Junta de Castilla y León (VA049A11, VA152A12 y VA155A12) y el Instituto de Salud Carlos III bajo el Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y León

A day-ahead irradiance forecasting strategy for the integration of photovoltaic systems in virtual power plants

Encouraged by the considerable cost reduction, small-scale solar power deployment has become a reality during the last decade. However, grid integration of small-scale photovoltaic (PV) solar systems still remains unresolved. High penetration of Renewable Energy Sources (RESs) results in technical challenges for grid operators. To address this, Virtual Power Plants (VPPs) have been defined and developed to manage distributed energy resources with the aim of facilitating the integration of RESs. This paper introduces a hybrid irradiance forecasting approach aimed at facilitating the integration of PV systems into a VPP, especially when a historical irradiance dataset is exiguous or non-existent. This approach is based on Artificial Neural Networks (ANNs) and a novel similar hour-based selection algorithm, has been tested for a real PV installation, and has been validated also considering irradiance measurements from an aggregation of ground-based meteorological stations, which emulate the nodes of a VPP. Under a reduced historical dataset, the results show that the proposed similar hour-based method produces the best forecasts with regard to those obtained by the ANN-based approach. This is particularly true for one-month and two-month datasets minimizing the mean error by 16.32% and 9.07% respectively. Finally, to demonstrate the potential of the proposed approach, a comparative analysis has been carried out between the hybrid method and the most used benchmarks in the literature, namely, the persistence method and the method based on similar days. It has been demonstrated conclusively that the proposed model yields promising results regardless the length of the historical dataset.Comunidad de MadridAgencia Estatal de Investigació

A prototype from the Solar Decathlon Competition becomes an educational building in sustanaible architecture

In 2008, the City Council of Rivas-Vaciamadrid (Spain) decided to promote the construction of “Rivasecopolis”, a complex of sustainable buildings in which a new prototype of a zero-energy house would become the office of the Energy Agency. According to the initiative of the City Council, it was decided to recreate the dwelling prototype “Magic-box” which entered the 2005 Solar Decathlon Competition. The original project has been adapted to a new necessities programme, by adding the necessary spaces that allows it to work as an office. A team from university has designed and carried out the direction of the construction site. The new Solar House is conceived as a “testing building”. It is going to become the space for attending citizens in all questions about saving energy, energy efficiency and sustainable construction, having a permanent small exhibition space additional to the working places for the information purpose. At the same time, the building includes the use of experimental passive architecture systems and a monitoring and control system. Collected data will be sent to University to allow developing research work about the experimental strategies included in the building. This paper will describe and analyze the experience of transforming a prototype into a real durable building and the benefits for both university and citizens in learning about sustainability with the buildin

Modelo integrado para la formación en tecnologías de fabricación para estudiantes de grado en el ámbito de la ingeniería industrial: caso práctico.

Caso práctico integración en fabricaciónDepartamento de Ciencias de los Materiales e Ingeniería Metalúrgica, Expresión Gráfica en la Ingeniería, Ingeniería Cartográfica, Geodesia y Fotogrametría, Ingeniería Mecánica e Ingeniería de los Procesos de Fabricació

LAL regulators SCO0877 and SCO7173 as pleiotropic modulators of phosphate starvation response and actinorhodin biosynthesis in Streptomyces coelicolor

[EN] LAL regulators (Large ATP-binding regulators of the LuxR family) constitute a poorly studied family of transcriptional regulators. Several regulators of this class have been identified in antibiotic and other secondary metabolite gene clusters from actinomycetes, thus they have been considered pathway-specific regulators. In this study we have obtained two disruption mutants of LAL genes from S. coelicolor (Δ0877 and Δ7173). Both mutants were deficient in the production of the polyketide antibiotic actinorhodin, and antibiotic production was restored upon gene complementation of the mutants. The use of whole-genome DNA microarrays and quantitative PCRs enabled the analysis of the transcriptome of both mutants in comparison with the wild type. Our results indicate that the LAL regulators under study act globally affecting various cellular processes, and amongst them the phosphate starvation response and the biosynthesis of the blue-pigmented antibiotic actinorhodin. Both regulators act as negative modulators of the expression of the two-component phoRP system and as positive regulators of actinorhodin biosynthesis. To our knowledge this is the first characterization of LAL regulators with wide implications in Streptomyces metabolismSIThis work was supported by the Spanish Ministerio de Ciencia e Innovación (BIO2007-67585 and BIO2010-19911 to JFA); and the Junta de Castilla y León (Grupo de Excelencia GR117). FPU fellowships of the Ministerio de Ciencia e Innovación (AP2005-3644 to JSA, AP2007-02055 to T.D.P.); a fellowship from the University of León (to SMG); and a contract from the Junta de Castilla y León (E-24-2009-0053914 to CMV). The funders had no role in study design, data collection and analysis, decision to publish, or presentation of the manuscript

An experience in integrated knowledge about Manufacturing Technologies for Students of the Grades of Industrial Engineering

Caso práctico integración en fabricaciónDepartamento de Ciencias de los Materiales e Ingeniería Metalúrgica, Expresión Gráfica en la Ingeniería, Ingeniería Cartográfica, Geodesia y Fotogrametría, Ingeniería Mecánica e Ingeniería de los Procesos de Fabricació

Aperiodic two-layer energy management system for community microgrids based on blockchain strategy

Regulatory changes in different countries regarding self-consumption and growing public concern about the environment are encouraging the establishment of community microgrids. These community microgrids integrate a large number of small-scale distributed energy resources and offers a solution to enhance power system reliability and resilience. This work proposes a geographically-based split of the community microgrids into clusters of members that tend to have similar consumption and generation profiles, mimicking the most typical layout of cities. Assuming a community microgrid divided into clusters, a two-layer architecture is developed to facilitate the greater penetration of distributed energy resources in an efficient way. The first layer, referred as the market layer, is responsible for creating local energy markets with the aim of maximising the economic benefits for community microgrid members. The second layer is responsible for the network reconfiguration, which is based on the energy balance within each cluster. This layer complies with the IEC 61850 communication standard, in order to control commercial sectionalizing and tie switches. This allows the community microgrid network to be reconfigured to minimise energy exchanges with the main grid, without requiring interaction with the distributed system operator. To implement this two-layer energy management strategy, an aperiodic market approach based on Blockchain technology, and the additional functionality offered by Smart Contracts is adopted. This embraces the concept of energy communities since it decentralizes the control and eliminates intermediaries. The use of aperiodic control techniques helps to overcome the challenges of using Blockchain technology in terms of storage, computational requirements and member privacy. The scalability and modularity of the Smart Contract-based system allow each cluster of members to be designed by tailoring the system to their specific needs. The implementation of this strategy is based on low-cost off-the-shelf devices, such as Raspberry Pi 4 Model B boards, which operate as Blockchain nodes of community microgrid members. Finally, the strategy has been validated by emulating two use cases based on the IEEE 123-node system network model highlighting the benefits of the proposal.Comunidad de Madri