1,720,959 research outputs found
Effect of different economic support policies on the optimal synthesis and operation of a distributed energy supply system with renewable energy sources for an industrial area
No full textThe paper presents a Mixed Integer Linear Program model of a distributed energy supply system for an industrial area located in the north-east of Italy. The system is composed of nine users connected through a district heating network, a set of combined heat and power units, integration boilers and a thermal storage tank. The electric energy may also be produced by solar photovoltaic modules and the heating energy by a solar thermal field.
The optimization algorithm determines the optimal structure of the energy system, all the installed components and their optimal operation. The objective function minimizes the total annual cost for owning, operating and maintaining the whole energy system.
The aim of the paper is to evaluate the effect of different economic support policies on the optimal solution and to compare the social cost of the application of each incentive with the CO2 emission reduction. The expectation is that a proper mix of renewable energy technologies and cogeneration systems will be included into the optimal solution, depending on the amount and nature of the supporting policies, highlighting the incentives that promote an actual environmental benefit
PROGETTO OTTIMO DI UN SISTEMA INTEGRATO CON IMPIANTO TRIGENERATIVO E RETE DI TELERISCALDAMENTO
No full textL’articolo riguarda l’ottimizzazione di un sistema di trigenerazione distribuita a servizio di sette utenze pubbliche, collocate nel contesto urbano di una piccola cittadina nel Nord-Est Italia. Il modello utilizzato ai fini dello studio, si basa su un algoritmo di ottimizzazione lineare intera mista (MILP) e permette di determinare la configurazione per la soddisfazione delle richieste energetiche delle utenze ottima dal punto di vista economico. La configurazione di generazione distribuita che deve essere ottimizzata comprende microturbine a gas per la cogenerazione, gruppi frigoriferi ad assorbimento, boilers, frigoriferi a compressione e una rete di teleriscaldamento/raffrescamento che connette fra loro le utenze.
L’obbiettivo dello studio è ottenere la configurazione ottima dell’intero sistema, determinando la localizzazione ed il numero delle macchine da installare, le caratteristiche ed il numero dei rami di rete da realizzare e la miglior strategia di gestione dell’impianto al fine di minimizzare i costi annuali di investimento, manutenzione ed esercizio.
Verranno considerati anche alcuni casi al variare dei fabbisogni energetici delle utenze e verrà analizzata l’influenza della riduzione del costo di realizzazione della rete di teleriscaldamento/raffrescamento sulla configurazione ottima
Optimal lay-out and operation of combined heat & power (CHP) distributed generation system
No full textThe paper presents an optimization model of a distributed cogeneration system with a district heating network, applied to a real city centre situation. The distributed urban cogeneration system includes both a set of micro-gas turbines, located inside some public buildings, and a centralized cogeneration system based on a Internal Combustion Engine. The objective function adopted for the optimization is the Total Annual Cost for owning, maintaining and operating the whole system. To face the problem a Mixed Integer Linear Program (MILP) is defined and solved by a commercial software. Starting from the thermal and electrical demand of the buildings, the MILP model allows to define the possible installation of the centralized cogeneration ICE and the number of micro-turbines in the different buildings, the optimal lay-out of the district heating network and the optimal operation strategy for the whole system as well. In particular the energy performance and global CO2 emissions are evaluated
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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