1,721,812 research outputs found
Multiobjective optimization for pricing system security in electricity markets
No full text(© 2003 IEEE) Milano, F., Canizares, C. A., & Invernizzi, M. (2003). Multiobjective optimization for Pricing System security in electricity markets. IEEE Transactions on Power Systems, 18(2), 596–604. https://doi.org/10.1109/tpwrs.2003.810897This paper proposes a novel technique for representing system security in the operations of decentralized electricity markets, with special emphasis on voltage stability. An interior point method is used to solve the optimal power flow problem with a multiobjective function for maximizing both social benefit and the distance to maximum loading conditions. A six-bus system with both supply and demand-side bidding is used to illustrate the proposed technique for both elastic and inelastic demand, and a 129-bus test system that models the Italian HV transmission network is used for testing the practical applicability of the proposed method. The results obtained show that the proposed technique is able to improve system security while yielding better market conditions through increased transaction levels and improved locational marginal prices throughout the system
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
Il tempo della città : una ricerca sull'uso del tempo quotidiano a Torino
Full text link4: Il tempo della città : una ricerca sull'uso del tempo quotidiano a Torino / di Maria Carmen Belloni ; presentazione di Luciano Gallino. - Milano : F. Angeli, c1984 - 337 p. ; 22 cm. ((Fa parte di : Progetto Torino : sette ricerche per una città. - Milano : F. Angeli. - v. ; 22 cm
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
Indennità d’accompagnamento (art. 1 legge n. 18/80), legge 104/92, prescrizione di ausili protesici.
No full textVoltage stability constrained OPF market models considering N-1 contingency criteria
No full textThis paper proposes two novel techniques for including contingencies in OPF-based electricity market computations and for the estimation
of a “system-wide” available transfer capability (SATC). The OPF problem formulation includes voltage stability constraints and a loading
parameter in order to ensure a proper stability margin for the market solution. Two methods are proposed. The first technique is an iterative
approach and computes an SATC value based on an N − 1 contingency criterion for an initial optimal operating condition, to then solve an
OPF problem for the worst contingency case; this process is repeated until the changes in the SATC values are below a minimum threshold.
The second approach solves a reduced number of OPF problems associated with contingency cases according to a ranking based on a power
transfer sensitivity analysis of the transmission lines. Both methods are tested on a 6-bus system and on a realistic 129-bus Italian network
model considering supply and demand side bidding. Local marginal prices and nodal congestion prices resulting from the proposed solutions
as well as comparisons with results obtained by means of a standard OPF technique are also presented and discussed
Participation of DERs to the Bottom-Up Power System Frequency Restoration Processes
No full textThis paper studies the transient behavior and frequency stability of a grid with a large share of distributed energy resources (DERs) during a bottom-up restoration process. This work is motivated by a real-world restoration process, during which the tripping of the DER frequency protections led to the frequency instability and finally to the collapse of the system. The main contribution of the paper is the proposal of a DER control strategy based on the estimation of the rate of change of frequency and fast frequency regulation. A comprehensive stochastic analysis in time domain shows that the proposed control effectively prevents the occurrence of the instability during the restoration process
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