1,720,957 research outputs found
Heuristic optimization applied to ANN training for predicting renewable energy sources production
Full text linkPredicting complex systems like Renewable Energy Sources depending nonlinearly on several physical parameters can be approached by a phenomenological method based on Artificial Neural Networks. This contribute shows the application of heuristic optimization algorithms to the training phase of ANN whose aim is to predict renewable power production as function of environmental variables like solar irradiance and temperature. The training problem is cast as the minimisation of a cost function whose degrees of freedom are the parameters of the neural network. A Differential Evolution algorithm is compared with the more usual gradient-based minimization procedure and the comparison of their performances is presented. In all the cases tested, Differential Evolution training process is showing results in line with those of the differential-based ones, with comparable convergence speed, always showing a more reliable behaviour, avoiding problems of premature convergence and overfitting affecting in some applications 20% of gradient-based procedures
Grid-friendly optimization of energy communities through enhanced multiple participation
No full textEnergy communities have been designed to promote sustainable development in the form of improved and affordable energy access, sustainable generation, and social inclusion. As their legislative background continues to evolve, future upgrades are expected to increase the benefits that these novel energy concepts offer. In Austria, from 2024 onwards, it will be possible to participate in more than one energy community at the same time; as such, it is necessary to evaluate the potential benefits for participants and the existing electricity grid. Thus, in this study, an optimization model is proposed to allocate the demand and production of each participant, generation unit, and storage initially belonging to different communities that are implemented under the same distribution transformer and engage in multiple participation. Both energy- and grid-related costs are minimized, and the benchmark independent energy community case is compared with the novel multiple participation. The influence of participants’ acceptance on providing flexibility (in the form of load shedding) is assessed through sensitivity analysis. The results show that, compared to the independent case, multiple participation could provide additional reductions in terms of emissions (3.5%), costs (up to 10%), and peak demand (up to 29%) at the transformer level. However, communities with higher generation shares could be individually disadvantaged compared to those with lower generation shares. Storage could also assist in reducing costs and peak demand, but at the cost of faster aging and with relatively small differences between the independent and multiple participation cases
Economic, Energy, and Environmental Analysis of PV with Battery Storage for Italian Households
Full text linkThe use of renewable energy sources is one way to decarbonize current energy consumption.
In this context, photovoltaic (PV) technology plays a direct fundamental role since it can convert sun
irradiance into electricity to be used for supplying electric loads for households. Despite the huge
availability of the solar resource, the intermittence of PV production may reduce its exploitation. This
problem can be solved by the introduction of storage systems, such as batteries, storing electricity
when PV overproduction occurs and acting as a source when PV generation is absent. Consequently,
increase in self-sufficiency and self-consumption can be expected in residential end users, paving the
way for more sustainable energy systems. In this paper, an economic, energy, and environmental
analysis of PV systems (without and with batteries) for the household is performed for the whole of
Italy, by means of a Geographical Information Systems (GIS) approach. A model to simulate energy
balance and to manage batteries is defined for households to assess the profitability of such systems
under an Italian regulation framework. Concerning results, indicators are provided at a national
scale using GIS tools to highlight areas where investments are more profitable, boosting the CO2
emission reductio
Economic assessment of multiple energy community participation
No full textEnergy Communities (ECs) have been introduced as a solution to address energy system development from a multidisciplinary perspective, with energy-related, environmental, and social targets as main pillars. While some countries still struggle with implementing basic rules for ECs, others, such as Austria, already go one step further and address the topic of allowing to participate in multiple ECs at the same time. The scientific literature to date lacks of studies that investigate whether it is profitable for a new participant to join multiple ECs instead of joining only one, and, which effect this would have on the existing ECs. Thus, this paper introduces a mathematical framework to optimally allocate a new participant within an existing set of ECs. The proposed economic-based decision making problem is formulated as a Mixed Integer Linear Programming (MILP) problem. While the model determines the economically optimal solution for a new participant, it is ensured that the initial situation of the existing ECs does not worsen. Results are provided for a set of ECs with different availability of resources and located in different settlement patterns, applying current Austrian legislation. Result shows that having multiple possibilities to share energy surplus and to satisfy energy demand can result in additional revenues of 6%, making multiple participation a valuable option to be considered by policy makers
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Recoupled: a simulation tool for renewable energy communities coupling electric and thermal energies
Full text linkIn this contribution, an optimization tool for the operational management of a REC Renewable Energy Community) is proposed. RECs can contain renewable energy technologies (photovoltaic or solar thermal panels, biofuel burners), electric, heating and cooling end users and coupling components (e.g., heat pumps)
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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