1,720,990 research outputs found
Smart sensor systems for environmental monitoring: implications and applications
No full textQuella del cambiamento climatico è una delle più grandi sfide che l'umanità dovrà affrontare nei prossimi decenni. Per questo, negli ultimi anni, gli sforzi della ricerca si sono focalizzati sullo sviluppo ed implementazione di sistemi distribuiti di monitoraggio ambientale. Questi sistemi sono in grado di produrre grandi quantità di dati, che possono essere usati per descrivere i cambiamenti climatici e, sperabilmente, indirizzare le future decisioni politiche allo scopo di mitigarne gli effetti. Ad ogni modo, per rendere questi sistemi effettivamente intelligenti, è necessario tenere in considerazione diversi aspetti, inclusi i due su cui si è focalizzato questo lavoro di tesi. Il primo, spesso sottovalutato, riguarda la progettazione dell'esperimento di acquisizione dei dati: infatti, un setting sperimentale poco consono porta a dati in qualche modo affetti da un bias, e, di conseguenza, a risultati non significativi. Il secondo aspetto invece riguarda l'algoritmo usato per modellare i dati, che dovrebbe essere scelto per riflettere la natura degli stessi. Questo lavoro prova quindi a dare un (primo) contributo ad entrambi questi aspetti, descrivendo i risultati di due specifici scenari di utilizzo, e mostrando come gli esperimenti possano beneficiare da alcune semplici linee guida. L'obiettivo finale a cui tende questo lavoro è quindi quello di definire una pipeline di elaborazione dei dati ambientali, che possa, a lungo andare, diventare abbastanza flessibile da essere adattata a scenari eterogenei e relativi ad una varietà di fenomeni ambientali.Climate change is one of the biggest challenges that humanity will face in the upcoming decades. Hence, over the last few years, the environmental engineering research community has focused its effort on the development and deployment of (often distributed) smart sensor systems, specifically designed for environmental monitoring. These sensors produce large amounts of data, which can be used to describe climate changes and, hopefully, suggest future actions to prevent further damages to the environment. However, to enable the ’smart’ capabilities in such systems, researchers must pay attention to several aspects, including two on which this thesis work is focused. The first one, which is often underestimated, is the design of the data acquisition phase: a poor experimental setting will lead to biased data, and therefore ineffective results. The second one concerns the algorithm used to model data, which should be chosen to reflect their intrinsic nature. This work tries to give a first contribution to both these aspect, describing the results of two specific use case scenarios, and highlighting how experiments can greatly benefit from some simple, yet effective, design guidelines. The final goal is to define an initial working pipeline for environmental data processing, which can be both flexible to be adapted to different scenarios, and accurate enough to give an effective description of the observed phenomena
An Efficient Object Based Personal Video Coding System
No full textA motion based unsupervised neural network approach to motion segmentation is addressed, and embedded in an automatic object based coding system. The motion estimation phase is carried out by an arbitrarily shaped object oriented block based technique (S-BMA). An efficient polynomial motion model is used to describe motion fields and jointly segment images into background-foreground. The proposed technique is embedded in a H.263-like coding system and tested on the foreman sequence. Preliminary results on standard video sequence seem promising
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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