1,720,958 research outputs found
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
Structural Health Monitoring of Additively Manufactured Components
Get PDFStructural Health Monitoring (SHM) methods evaluate the condition of machine components by using permanently installed sensors to assure the safe operation of machines, reduce maintenance costs, and eliminate the need for periodic inspections. Additive manufacturing (AM) has become a new production tool for the creation of complex parts and the reduction of the number of assembled components. The customized design of the internal geometry of AM parts is another advantage of it over conventional methods. In the present study, Surface Response to Excitation (SuRE) method was applied to additively manufactured parts in order to detect, localize, and evaluate the severity of the structural defect or applied load on the structure. SuRE method excites the surface of the structure by mechanical waves using a piezoelectric element. One or multiple piezoelectric elements are used to monitor the dynamic response to excitation at desired locations. To quantify the changes in the frequency spectrum of the monitored signals, the sum of the squared differences (SSD) can be used.
In this dissertation, three deep learning models (1D-CNN, 2D-CNN, and LSTM) have been developed for the classification of the recorded data. While 1D-CNN and LSTM models work directly with time-domain data, 2D-CNN requires a signal processing step to convert the sensor data into images. Four major studies have been performed for condition monitoring of AM components. First, the wave propagation characteristics and fault localization in AM parts were examined with respect to infill type. In the second study, identical test specimens were fabricated with different print orientations, and three excitation signals were used to analyze the time domain response, compare the wave travel speed, and distinguish the data based on the print orientation and applied load. In the third study, the SSD index and the abovementioned DL algorithms are compared for estimating the damage length. In the fourth study, load sensing was investigated on conventionally and additively manufactured metallic bars using 2D-CNN and LSTM models. The results showed that the SSD metric successfully detects anomalies in the structure, while it is not as accurate as deep learning models in estimating the damage severity
Optimization methods for grid-scale battery energy storage system
No full textLAUREA MAGISTRALELa transizione verso le Microgriglie (MG) con Fonti Energetiche Rinnovabili (RES) rap- presenta un cambiamento cruciale nella nostra ricerca di soluzioni energetiche sostenibili. Questa tesi si concentra sulla dimensione ottimale dei Sistemi di Accumulo di Energia a Batteria (BESS) all’interno di una Microgriglia che combina in modo sinergico l’energia proveniente da installazioni Fotovoltaiche (PV) e parchi eolici. Poiché le fonti energetiche solare ed eolica incarnano purezza e sostenibilità, il BESS si pone come un componente essenziale per garantire la affidabilità e la stabilità dell’approvvigionamento energetico. Questa ricerca introduce tre distinte strategie di ottimizzazione, una dedicata alla mas- simizzazione dei ricavi, un’altra incentrata sulla riduzione dei costi e l’ultima volta a garantire l’operatività della MG in modalità isola. Inoltre, si approfondisce il ruolo in- fluente del BESS nell’incremento della qualità dell’energia elettrica all’interno della MG. Questo studio sottolinea il ruolo indispensabile del BESS nel migliorare le prestazioni e la sostenibilità economica dell’integrazione di energie rinnovabili nelle Microgriglie.The transition to Renewable Energy Source (RES) Microgrids represents a pivotal shift in our quest for sustainable energy solutions. This thesis centers on the optimal sizing of Battery Energy Storage Systems (BESS) within a Microgrid (MG) that seamlessly combines the power of Photovoltaic (PV) and Wind Farm installations. As wind and solar energy sources embody purity and sustainability, BESS emerges as a critical component in ensuring the reliability and stability of power supply. This research introduces three distinct optimization strategies, one dedicated to revenue maximization, the other focused on cost reduction, and the last targeting the operation of MG as off-grid. Furthermore, it delves into the influential role of BESS in elevating the power quality within the MG. This study underscores the indispensable role of BESS in enhancing the performance and economic viability of renewable energy integration in Microgrids
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
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
The effect of hidden geometry on the signal characteristics in additive manufactured parts
No full textStructural health monitoring (SHM) has been used in various engineering sectors such as aerospace and civil engineering applications for reducing maintenance costs and to operate the system safely by detecting faults in the system. Additive manufacturing (AM) was used primarily for prototyping but recently many parts are produced for actual use to benefit from the layer by layer part generations. AM can generate very complex geometries which cannot be manufactured by convention manufacturing. The internal hidden geometry of an AM part can be designed to simplify the defect location estimation by using SHM methods. A PLA cross-shaped part was designed and fabricated by the Fused Deposition Modeling (FDM) method. Each extension of the part had different internal geometry. The part was excited at the center with the impact of a hammer and the response to the excitation was monitored by the attached piezoelectric discs at the end of each extension. The recorded data from sensors were plotted and compared in the time-domain, frequency-domain (Fast Fourier Transform(FFT)), and in the time-frequency domain (Short-Time Fourier Transform (STFT), and the Continuous Wavelet Transform (CWT)). The results showed that the hidden geometry of each extension had a different effect on the wave characteristics. Lamb waves traveles with lower attenuation at sections with higher infill ratio
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