1,720,967 research outputs found
Real time enhancement of cephalometric radiographies
No full textWe present here a real time filtering procedure, called S.Ti.F., which is able to make both soft and bone tissue clearly visible into a cephalometric radiography. Histogram based clustering allows separating the bone pixels from the other ones. Different gamma corrections are then applied to bone and soft tissue areas, in order to obtain a clear visualization of the local anatomical structures. Trials on a large dataset of images demonstrated the power of the proposed filter. The real time processing and the possibility to interactively modify the filter parameters make it a very useful tool for dentists and surgeons
A new switching median filter for digital radiography
No full textLocalized hardware failures on sensor and communication channel often introduce in digital radiographies a characteristic impulsive noise, known as "salt & pepper". Eliminating these failures, which generate the corrupted pixels, is a very costly or even impossible task; therefore, image processing techniques have been developed to correct the gray level values of these pixels. We propose here a new switching median filter for digital radiography, which has been inspired by the properties of the human visual system: a pulse is detected on nie radiography by measuring its visibility in terms of local contrast and signal to noise ratio. The local background value is estimated applying a 3×3 median filter to the image, and noise distribution is evaluated by means of a simple and reliable model, which describes the properties of the digital sensor and incorporates the statistical characteristic of the noise. Since the filter requires no iteration, it can work in real time also on large images (less than 0.7s for 12 bit, 4.8MPixel images). The presence of edges does not affect the pulse detection and correction, thus resulting in a more efficient approach with regards to more traditional methods. Some residual pulse may remain visible only in the darkest zones of the radiography, which are usually poor of diagnostic information
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
Optimized acquisition geometry for X-ray inspection
No full textX-ray inspection of luggage and cargo containers is nowadays fundamental to guarantee the security in the field of transportation. The simplest inspection systems currently in use are based on transmission radiography, but high absorption objects may hide to the inspector the presence of weapons or other dangerous materials. Dual-energy views are used to automatically recognize nuclear and explosive materials, but also in this case high absorption objects may make the recognition results unreliable. Computerized tomography (CT) partially solves these problems, but it generally represents a costly and slow inspection method. In this paper, we suggest to use a fast, adaptive multi-view system where the geometry of the X-ray projecting cones are set according to an empirical criterion aimed at facilitating the recognition of all the objects inside the scanned volume. Experimental results on simulated and real data are reported in the paper to demonstrate the reasonableness and efficacy of the proposed criterion
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
- …
