1,720,999 research outputs found
3D modeling, reconstruction and analysis of environments assisted by multi-sensorial data processing
Full text linkIl lavoro descritto in questa Tesi di Dottorato ricade nella categoria generale della Computer Vision. Più specificamente, le tematiche di modellazione, ricostruzione e analisi tridimensionale di ambienti sono state trattate da molteplici punti di vista in modo tale da investigare metodologie efficaci ed efficienti per acquisire i dati ed effettuare le opportune elaborazioni successive. L'attività di costruzione di modelli mediante sistemi di visione automatici induce la ricerca costante di tecniche innovative che garantiscano sia il rispetto dei requisiti di sistema, sia la capacità di gestire in maniera efficiente e ottimizzata notevoli moli di dati.
I problemi da risolvere in questo ambito spaziano dalla modellazione dello sfondo di una scena fino al tracking di un oggetto, dall'analisi di una nuvola di punti 3D fino all'identificazione di un movimento, una traiettoria o una caratteristica distintiva di un oggetto in uno spazio tridimensionale. Tutti questi compiti sono connessi a problemi aperti nel campo dell'elaborazione di immagini e video, dal momento che un'implementazione efficiente è strettamente connessa all'abilità di un sistema di rappresentare correttamente una scena complessa o di interpretare efficacemente la semantica di un video acquisito. Per questa ragione, lo scopo generale di questo lavoro è l'analisi di situazioni complesse (ad esempio indoor, outdoor, con e senza controllo di illuminazione, con parecchi oggetti in movimento etc...) tramite metodi innovativi di acquisizione e analisi dei dati.
Allo stato attuale esistono due tipi di nuvole di punti – dense e sparse – classificate in base al numero di punti 3D che sono contenuti in una acquisizione. Entrambe le tipologie di dato sono state trattate durante il lavoro, comprese le opportune metodologie per trattare ognuna di queste.
I sensori basati sui laser sono largamente impiegati nella creazione di modelli tridimensionali di una scena, dal momento che sono in grado di fornire informazioni dettagliate (nuvole di punti dense) circa la profondità di un oggetto che viene illuminato dalla sorgente luminosa, garantendo una delle due seguenti proprietà: elevato throughput del sensore o un largo campo di vista fino a 360°.
Il primo obiettivo del lavoro ha riguardato la progettazione, la prototipazione e il test di un sensore 3D catadiottrico omnidirezionale miniaturizzato, capace di fornire un elevato throughput e un largo campo di vista. Inoltre, una nuova metodologia per la registrazione di nuvole di punti dense è stata investigata e dettagliata. I risultati ottenuti sono di rilevante interesse poiché suggeriscono e incentivano l'utilizzo di tali sistemi in scenari industriali per scopi di monitoraggio, per effettuare controlli non distruttivi o – più genericamente – analisi degli oggetti.
Un'altra tecnica nota per risolvere il problema della modellazione tridimensionale è la stereovisione, che viene impiegata per valutare la distanza di un punto simultaneamente catturato da due o più sensori (telecamere). La stereovisione evita l'utilizzo di sorgenti laser, ma produce dati altamente ridondanti che devono essere elaborati per ricavare una nuvola di punti sparsa. Infatti, è obbligatorio collezionare ed elaborare almeno due differenti flussi video per ottenere informazioni 3D sulla scena ripresa, senza considerare lo sforzo necessario a stabilire le corrispondenze tra i punti di due viste differenti.
Il secondo obiettivo del lavoro ha riguardato la progettazione e lo sviluppo di un prototipo semi ingegnerizzato di sistema stereo per la valutazione di situazioni complesse, applicato al contesto sportivo (in particolare al tennis). Tale sistema è in grado di analizzare tattiche di gioco di un giocatore mediante inferenze logiche che vengono effettuate dopo aver eseguito specifiche query per combinare i dati estratti da ogni modulo software implementato secondo le specifiche dettagliate da un esperto di dominio.
Riassumendo, il lavoro è stato incentrato alla progettazione ed implementazione di sistemi intelligenti per l'analisi di scene complesse mediante l'utilizzo di dati 3D. Questo implica l'investigazione di nuove tecniche di analisi dei dati e l'ottimizzazione degli algoritmi già noti in letteratura. Infatti, una volta che la nuvola di punti è stata prodotta, c'è la necessità di elaborarla opportunamente per compiere azioni di alto livello, come ad esempio l'identificazione di un oggetto o di un soggetto, il suo tracciamento nello spazio 3D o l'analisi semantica della scena.The work described in this thesis falls in the general category of computer vision. More specifically, 3D modeling, reconstruction and analysis of environments is treated from multiple points of view in order to provide effective and efficient methods to capture data and perform complex processing tasks. Building a model by means of an automated machine vision system induces the research of constantly new techniques to make the final system both able to fulfill the requirements and optimized to efficiently perform proper tasks.
The problems that need to be solved relatively to these topics spread from the background modeling of a scene to moving object tracking, from 3D point cloud analysis to the identification of a motion, a trajectory or a particular feature of an object in the three dimensional space. All these tasks are related to open problems in the image/video processing field, since their efficient implementation is strictly related to the ability of a system to correctly represent a 3D complex scene or to the effective understanding of the semantics of an acquired video. For this reason, the main focus of this thesis is on the analysis of complex situations (i.e. indoor, outdoor, with and without controlled illumination, with many moving subjects) by means of innovative data acquisition and processing techniques.
Two types of point clouds actually exist - dense and sparse - depending on the number of 3D points that are contained in the acquisition. Both of them will be treated in this thesis, along with proper methodologies to deal with the specific type of data.
Laser based sensors are largely employed to create a 3D model of a generic scene, since they are able to provide detailed information (the so called Dense point clouds) about the depth of an object that is illuminated by the light source, guaranteeing one of the two following capabilities: high data throughput or large sensor field of view, up to 360°.
The first objective of this thesis will be the design, prototype and test of a miniaturized omnidirectional 3D catadioptric sensor capable of both high throughput and large field of view. Also, a new methodology to perform 3D dense point clouds registration will be investigated and detailed. Such systems are of relevant interest and can be effectively employed in industrial applications for monitoring purposes, to perform non destructive tests, quality control or - more generally - objects analysis.
Another well known technique used to solve the 3D modeling problem is stereovision, that is used to evaluate the depth information about a point that is simultaneously captured by two or more sensors (cameras). Stereovision avoids the use of laser sources, but produces highly redundant data that needs to be exploited to compute a sparse point cloud. In fact, it is mandatory to collect and process at least two distinct videos to obtain 3D information about the scene, regardless the effort that is needed to estabilish the correct correspondence between points from distinct views.
The other objective of this thesis will be the design and development of a semi-engineered stereo system prototype for evaluating complex situations, applied to the sportive context (in particular, the tennis one). This system will be able to analyze game tactics of a specific player by logical inferences that will take place after having executed specific queries that should properly combine data extracted from each software module.
In summary, the aim of this thesis is the design and development of intelligent systems for the analysis of complex scenes by using 3D information. This leads to the study of novel techniques, as well as the optimization of known algorithms. In fact, once the 3D point cloud is extracted, it needs to be appropriately processed to perform, for example, the identification of an object or a subject, its tracking in the 3D space or the semantic analysis of the scene. The ability of interpreting a scene via software starting from the output of a camera or a depth sensor is an ambitious objective of certain scientific interest. Nevertheless, it is necessary to develop new methodologies as well as optimize and revise the known ones to achieve this goal, because semantic analysis highly depends on all the other software modules of the vision system (both 2D or 3D). Good models and effective processing algorithms are the keys to enable reliable high level modules on complex systems
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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