1,720,957 research outputs found
Sensitivity Factors for Integrated Energy Systems: A Joined Quasi-Steady-State Approach
Get PDFIntegrated energy systems can increase the use of volatile renewable energy generation while reducing operation cost in the electric power system. The benefits result from shifting energy between energy infrastructures and using the network storage capability of district heating and gas systems. But the more strongly the different energy systems are linked the more complex their operation becomes. To ensure a secure and reliable system operation while using the full potential of integrated energy systems the interactions and the network storage effects of the district heating and gas system must be analyzed. Existing power flow calculation methods of integrated energy systems, however, neglect the network storage effects which result from the dynamic behavior of the district heating and gas system. The dynamic behavior is only investigated if the different energy systems are solved separately. As existing methods do not directly represent the interactions and effects of the dynamic behavior in an integrated energy system, the effect of any unit's power change on the power flows in the integrated energy system can only be determined by a complete power flow calculation, leading to a high computational cost. To reduce the computational cost this thesis derives sensitivity factors estimating the effect of a power change on the system state of an integrated energy system. To derive the sensitivity factors a joined quasi-steady-state power flow calculation method for integrated energy systems is developed extending existing steady-state approaches. For this, the system state of the electric power system, district heating system, and gas system is determined simultaneously, directly representing their interactions. To include the dynamic behavior a gradient method is proposed, which allows temperature and calorific value changes to be tracked in a coupled power flow calculation. The gradient method can accurately depict the dynamic behavior in the joined quasi-steady-state power flow calculation method even with simulation time increments of up to 60 min. Hence, compared to existing methods larger simulation time increments can be chosen to reach the same accuracy, leading to a reduced computation time. The sensitivity factors are on average ten times faster in estimating a new system state after a unit's power change compared to a power flow calculation. Besides the high computational efficiency, they can provide good estimates considering the complexity of the interactions and the dynamic behavior in an integrated energy system. As the joined quasi-steady-state power flow calculation method is based on the steady-state analysis existing use cases can be easily extended to consider the full potential of integrated energy systems. Therefore, the thesis provides system operators with a method to accurately analyze the full potential of Integrated energy systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Combined Thermo-Electrical Simulation Model for Large-scale Battery Electrical Storage Systems
No full text7 S.The self-consumption of the peripheral equipment, especially the cooling system, of a large-scale battery electric storage systems (BESS) affects its overall efficiency. Simulation models can help estimating the efficiency in the design process, but existing models mostly focus on the electrical behavior of smaller storage systems not including peripheral equipment. Here, a model is developed that displays the electrical and thermal behavior of a large-scale BESS and includes its peripheral equipment. The model is validated with measurement data of an operating 1 MW system and it is shown that the model displays the electrical behavior with a relative deviation of 10 %; the thermal behavior with 27 %. Three parameters are varied investigating the impact of the cooling system on the efficiency: nominal thermal power, target temperature and temperature bandwidth of the cooling system. Decreasing the nominal power improves the overall efficiency, whereas varying the temperature bandwidth and target temperature has a minor effect
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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