1,720,961 research outputs found
Optimal Planning with Technology Selection for Wind Power Plants in Power Distribution Networks
No full textThis paper proposes a comprehensive decision framework to optimally plan wind power plants (WPPs) with technology selection in the distribution network. The proposed framework aims to maximize the net present value (NPV) associated with the WPP investment over a given planning horizon for various bus locations. The proposed design accounts for various practical cost factors, historical data of wind speeds, and WPP installation restrictions due to territorial information, environmental considerations, and work constraints, in the decision making process of optimal planning and technology selection for WPP. The planning problem, which maximizes the NPV over the potential WPP installation locations, potential technologies, and the size of WPPs, is formulated as a constrained optimization problem. The proposed design is evaluated using case studies to test its concrete practices with a radial network of 33-bus distribution system
Reinforcement Learning Based Penetration Testing of a Microgrid Control Algorithm
No full textMicrogrids (MGs) are small-scale power systems which interconnect distributed energy resources and loads within clearly defined regions. However, the digital infrastructure used in an MG to relay sensory information and perform control commands can potentially be compromised due to a cyberattack from a capable adversary. An MG operator is interested in knowing the inherent vulnerabilities in their system and should regularly perform Penetration Testing (PT) activities to prepare for such an event. PT generally involves looking for defensive coverage blind spots in software and hardware infrastructure, however the logic in control algorithms which act upon sensory information should also be considered in PT activities. This paper demonstrates a case study of PT for an MG control algorithm by using Reinforcement Learning (RL) to uncover malicious input which compromises the effectiveness of the controller. Through trial-and-error episodic interactions with a simulated MG, we train an RL agent to find malicious input which reduces the effectiveness of the MG controller
Stochastic constrained linear quadratic control in a network of smart microgrids
No full textChallenges of microgrids (MGs) energy management have gained more relevance with the presence of uncertainties in power generation and local loads. These problems significantly increase when related to network of smart MGs (NSMG). To address these challenges, this study presents a stochastic constrained control problem for the optimal management of a cooperative NSMG with interconnections allowing power exchanges. In this model, each MG can exchange power locally among each other as well as with the main electric grid. The proposed control approach is based on a linear-quadratic Gaussian problem definition for the optimal control of power flows under quadratic constraints limiting the variability of the power exchange as well as of the stored energy in each MG. The developed framework is applied to a cooperative network of four smart MGs to test and validate its effectiveness and performance. The network is connected to the main electric grid allowing power exchanges. The results demonstrate that the role of energy storage systems is undoubtedly becoming more and more relevant in the context of reacting to the stochastic behaviour of the balance between produced and consumed powers in MGs
Towards a Concept of Cooperating Power Network for Energy Management and Control of Microgrids
No full textThis chapter provides an outline of the operation and control of smart microgrids as well demand-side management and demand response programs, in addition to energy market trading. Furthermore, the chapter introduces the concept of coordination and interconnection of a set of smart microgrids in a network, showing its benefits, advantages, and outcomes, and presents an overview of the mathematical modeling of the network and its features as well as a description of robust control methods adapted to optimally control the energy exchanges at the network level considering uncertainties of loads and energy production
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
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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