1,720,972 research outputs found
Fast hybrid optmization method for effective pump scheduling
No full textThe cost of electricity used for pumping in water-distribution systems typically represents the largest part of the total operational costs. Therefore, optimization of pump operations is a major concern for water utilities around the world, especially in recent years with significantly increasing energy prices. Recently, to maximize cost and energy savings, pump scheduling is frequently done in real time by integrating the relevant optimization software into the water company’s supervisory control and data acquisition (SCADA) system. This, however, requires solving a complex, large, nonlinear optimization problem in a computationally efficient manner, typically in less than 1 h. To achieve this, the pump-scheduling problem is solved in this paper by a novel hybrid optimization method that uses linear programming (LP) and a greedy algorithm: LPG. The new methodology is applied to two case studies: the artificial, benchmark case study of Anytown network and the real-life pump-scheduling problem of the Richmond water-distribution network (WDN) in the UK. The results obtained clearly demonstrate that the LPG hybrid method is capable of solving real-life pump-scheduling problems in an extremely computationally efficient manner while preserving the accuracy (i.e., the near optimality) of the obtained solution. This makes the method particularly appealing for use in real-time pump-scheduling applications
Numerical modeling and leakage reduction in the water distribution system of Udine
No full textThe paper describes the effective achievements in terms of water supply and water resources management obtained by AMGA
S.p.A. within the GAP-UK Project (Interreg IV Programme). Two main issues are addressed, namely, the calibration of the
numerical simulation model and the water loss reduction which has been obtained after extensive leakage identification and
repair campaigns performed all over the network. In particular, the priority of leakage identification and repair has been
assigned to those sectors affected by a high rate of water loss, as a result of modeling and monitoring, thus confirming some
model prediction. All the identified leakages have been repaired and the effect on the global water balance of the system is
evident, characterized by a minimum night flow which passed from 215 L/s down to 165 L/s
Calibrazione e gestione della pressione nelle reti di distribuzione idrica: un caso applicativo
No full text
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
Calibration and Optimal Leakage Management for a Real Water Distribution Network
No full textThe aim of the paper is to present two optimization methodologies applied to a real water distribution system. The first one
involves model calibration, while the second addresses the problem of optimal leakage management. Model calibration is based on a
single objective, real-coded genetic algorithm, which provides optimal values of pipe friction factors and a leakage-dependent coefficient.
Leakage management is accomplished through the introduction and regulation of pressure reducing valves. To this end, the writers
adopted an approach based on multiobjective genetic algorithms, searching for the optimal placement and regulation of such valves. In
particular, the first criterion is represented by the minimization of the number of valves, while the second is the minimization of the total
leakage in the system. The algorithm provided several trade-off alternatives between leakage reduction and installation costs: the water
utility managing the system chose to place and regulate the first four valves identified by the algorithm, resulting in a water loss reduction
as evidenced by the continuous monitoring of the system after valve installation and in a decrease in pumping costs
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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