1,720,968 research outputs found
A low-cost structural health monitoring system for residential buildings: experimental tests on a scale model
No full textUna delle questioni più importanti riguardante l’Ingegneria civile e meccanica
è il rilevamento di danni strutturali. Una struttura civile, durante la sua
vita utile, oltre all’ordinaria esposizione ai carichi di servizio e ambientali, può
essere sottoposta episodicamente anche carichi più rilevanti come ad esempio
i terremoti. Questi eventi possono avere un profondo impatto sulla sicurezza
degli edifici e diventa opportuno, o in molti casi necessario, un continuo monitoraggio
delle condizioni di salute della struttura. Le tecniche più utilizzate
sono quelle di monitoraggio strutturale o Structural Health Monitoring (SHM).
Queste consentono di fornire una preziosa conoscenza del comportamento dinamico
delle strutture monitorate, della loro risposta in condizioni di servizio
sotto carichi ambientali, o sottoposte a situazioni di sollecitazione più rilevanti.
Tali sistemi sono largamente impiegati nelle applicazioni di ingegneria meccanica,
aeronautica e civile (soprattutto per strutture rilevanti), e in genere si
basano sulla misura e sullo studio delle vibrazioni di risposta a diversi input.
Lo sviluppo di dispositivi di misura a basso costo e a basso consumo energetico,
la disponibilità di sistemi di acquisizione di ultima generazione e di software
avanzati per l’analisi dinamica delle strutture rendono possibile l’applicazione
di tecniche di monitoraggio strutturale non solo a strutture strategicamente
significative (grandi infrastrutture, etc.), ma anche ad edifici ordinari. In tale
contesto, lo scopo di questa ricerca è quello di proporre una nuova metodologia
sperimentale e numerica per eseguire il monitoraggio di strutture civili, utilizzando
un prototipo di sistema SHM a basso costo, caratterizzato da sensori
MEMS e da strumenti di acquisizione di nuova generazione. Per questo motivo
è stato realizzato un modello in scala di un edificio a tre piani. Il modello è stato
strumentato e sottoposto a prove dinamiche cicliche. Sul modello sono stati
inseriti insieme ai tradizionali accelerometri piezoelettrici dei sensori MEMS,
in modo da poter confrontare i risultati e valutare le prestazioni di questi ultimi.
Sono state eseguite diverse prove dinamiche utilizzando due diversi tipi di
sensori per fare un’analisi comparativa del rumore di fondo, della risposta dinamica
e dello sfasamento in differenti condizioni operative. I risultati ottenuti
dai sensori a basso costo hanno evidenziato delle buone prestazioni paragonabili
a quelle degli accelerometri piezoelettrici. I dati acquisiti dal sistema sono applicati
a un modello numerico agli elementi finiti (FE) per rilevare l’esistenza, la
distribuzione e l’entità di danni locali e valutare quindi la vita utile rimasta. Il modello numerico (FE) della struttura è stato sviluppato e verificato sulla base
dei risultati ottenuti dall’ identificazione sperimentale dei parametri modali
della struttura, eseguita utilizzando le tecniche di analisi modale sperimentale
EMA (input-output) e di analisi modale operazionale OMA (output-only).
I parametri modali stimati sono stati utilizzati per controllare il modello FE.
L’analisi e il confronto dei risultati teorici e sperimentali ottenuti permettono di
affermare che il sistema proposto rappresenta una soluzione adeguata in termini
di costi, di affidabilità della misura dei sensori che registrano gli input dinamici
e di previsione della vita residua della struttura a seguito di un fenomeno
rilevante. La vita utile stimata dal modello in scala ottenuta mediante indici
danno locale e globale è coerente con i risultati sperimentali
Ba virtual and inter-organizational evolution: a case study from a EU research project
No full textPurpose: Taking Nonaka’s SECI model as the main reference, this paper aims to offer reflections on the virtual evolution of ba, the places for knowledge creation. Indeed, looking at the current scenario, widening the knowledge spiral to the inter-organizational epistemological level is inevitable. To this aim, information technology tools and virtual communities can establish effective interactions to exchange knowledge, making ba evolve congruently. Design/methodology/approach: The paper takes the exemplary case of a platform developed during a European research project called “BIVEE: Business Innovation in Virtual Enterprise Environments”. The investigative approach chosen is participatory action research (PAR), with two researchers conducting PAR in real time, and two others involved ex post. Findings: The paper shows that the virtual evolution of ba can lead the SECI model towards an inter-organizational level. Moreover, through a learning history, it describes how all the phases of the SECI process, even the Socialization one, can take place or be supported in virtual spaces. Research limitations/implications: Taking into account just one single exemplary case study provides a rich, contextualized understanding of phenomena, while allowing only some theoretical generalizations. Originality/value: This paper contextualizes the SECI model within a Web platform for open innovation, to investigate whether the knowledge creation process can take place entirely within a virtual environment linking subjects from different organizations. In so doing, it applies the SECI model to the phases of the innovation process, called waves
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
Proof of concept of the structural health monitoring of framed structures by a novel combined experimental and theoretical approach
Full text linkOne of the most important issues in engineering is the detection of structural damages. During its life cycle, a building, besides the exposure to operational and environmental forces, can be subjected to earthquakes or to other non-ordinary loads. These events may have a deep impact on the building safety, and thus, a continuous monitoring of the structure health conditions becomes desirable or even necessary in many cases. In this context, the usage of vibration-based structural health monitoring (SHM) systems is spreading from big infrastructures applications, like bridges, dams or skyscrapers, to the historical heritage and to public or residential buildings. The aim of this work is to propose a combined experimental and numerical methodology to perform the SHM of structures of the civil engineering lying in seismic hazard zones. A relatively low cost SHM prototype system based on this approach is developed. The data acquired by the system are provided to a finite element method (FEM) numerical model to detect the appearing, the rise and the distribution of local damages and to estimate a global damage level. The system has been tested and calibrated on a three-storey prototype model. The procedure for the estimation of the damage level is calibrated by comparing the experimental quantities measured during cyclic failure tests with the FEM model predictions
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
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
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