1,720,974 research outputs found
Glandular trichome-derived sesquiterpenes of wild tomato accessions (Solanum habrochaites) affect aphid performance and feeding behavior
No full textWang, Fumin, Park, Yong-Lak, Gutensohn, Michael (2020): Glandular trichome-derived sesquiterpenes of wild tomato accessions (Solanum habrochaites) affect aphid performance and feeding behavior. Phytochemistry (112532) 180: 1-11, DOI: 10.1016/j.phytochem.2020.112532, URL: http://dx.doi.org/10.1016/j.phytochem.2020.11253
Review of unsupervised machine learning methods in active infrared thermography for defect detection and analysis
No full textThe presence of internal defects poses a serious challenge to the structural integrity and performance of composite materials such as polymers and cultural heritage. Therefore the application of non-destructive testing (NDT) techniques is essential. Active infrared thermography (AIRT) is becoming increasingly attractive among many NDT techniques due to its low–cost and wide–area coverage advantages. However, thermograms often involve non–uniform backgrounds and measurement noise caused by uneven heating and environmental reflections, necessitating post-processing procedures. Among the research topics in this area, unsupervised machine learning methods have shown promising success in AIRT for defect detection. This paper aims to provide a recent overview of unsupervised machine learning-aided thermography for defect detection. Six perspectives on the role of machine learning in thermogram sequence processing are presented: image denoising, non-uniform background removal, image super-resolution enhancement, feature extraction, image segmentation, and depth prediction. In particular, deep learning methods for thermographic data analysis are reviewed and emphasised. A step-by-step review of treatment options offers a guide for inexperienced readers and investigators entering the field. Additionally, the development of machine learning-based thermography methods for different scenarios is summarised from an application perspective. Finally, an outlook on the prospects and potential of these methods is provided
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
Solanum habrochaites subsp. chemotypes S. Knapp & D. M. Spooner
No full text2.2. Identification of S. habrochaites chemotypes affecting longevity and fecundity of aphids As a first step to characterize the potential of the different S. habrochaites chemotypes to affect M. euphorbiae, we performed non-choice assays utilizing all S. habrochaites accessions and the two S. lycopersicum cultivars for comparison. Newly emerged M. euphorbiae nymphs were reared in clip cages on the leaf surface of the different tomato accessions, and their longevity and fecundity (represented by the number of offspring) were determined. No significant differences were observed for both performance parameters between the two S. lycopersicum cultivars, c.v. M82 and c.v. Moneymaker (Fig. 1). Compared to S. lycopersicum c.v. M82 the longevity of M. euphorbiae was not significantly different on leaves of the S. habrochaites chemotypes 1 and 3, and accession LA1721 of chemotype 2 (Fig. 1A) characterized by the dominant production of 7-epi-zingiberene, germacrene C (δ- elemene), and germacrene B (γ- elemene), respectively (Table S1, S2). Macrosiphum euphorbiae kept on accession LA1927 of chemotype 2 showed only a small reduction in their longevity (Fig. 1A). In contrast, the longevity of M. euphorbiae on accessions of chemotype 4 (LA1775, LA1779) and 5 (LA1624, LA2860), characterized by production of α- santalene/α- bergamotene/β- bergamotene and β- caryophyllene/ α- humulene, respectively, was reduced quite significantly (24.6%– 35.3% of the aphid longevity on c.v. M82) (Fig. 1A). Similar trends as observed for the longevity of M. euphorbiae were also found for their fecundity on the different S. habrochaites accessions. The numbers of M. euphorbiae offspring were not significantly different on accession LA1691 (chemotype 1), LA1721 (chemotype 2), and both accessions of chemotype 3 compared to S. lycopersicum c.v. M82 (Fig. 1B). Accessions LA2650 (chemotype 1) and LA1927 (chemotype 2) had a 53.6% and 45.9% reduction in fecundity, respectively. However, the most severe effect on fecundity was again observed for M. euphorbiae on accessions of the chemotypes 4 and 5 which almost completely lacked the emergence of nymphs (Fig. 1B). Thus, the results of the non-choice assays suggested that the sesquiterpenes produced in S. habrochaites accessions of the chemotypes 4 and 5 might have the potential to significantly affect the performance of M. euphorbiae.Published as part of Wang, Fumin, Park, Yong-Lak & Gutensohn, Michael, 2020, Glandular trichome-derived sesquiterpenes of wild tomato accessions (Solanum habrochaites) affect aphid performance and feeding behavior, pp. 1-11 in Phytochemistry (112532) (112532) 180 on page 3, DOI: 10.1016/j.phytochem.2020.112532, http://zenodo.org/record/829269
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
Enhancing defect detection in active infrared thermography using adaptive background suppression techniques
No full textRecent advancements in dimensionality reduction techniques have significantly contributed to the field of active infrared thermography (AIRT) for defect detection, aiding in data processing and feature extraction. Among these techniques, principal component thermography (PCT) and deep autoencoder thermography (DAT) are particularly notable. PCT is based on conventional linear multivariate analysis, while DAT leverages deep learning paradigms to better handle nonlinearity. These methods consolidate defect information from multiple thermograms into a concise set of feature images, enhancing the visibility of subsurface material defects. However, these feature images often suffer from disturbances, particularly non-uniform backgrounds caused by uneven heating in AIRT experiments. Such interferences can obscure defect information, necessitating further post-processing. In our research, we explore the efficacy of Adaptive Iteratively Reweighted Penalized Least Squares (AIR-PELS) as a refinement technique for PCT and DAT, focusing on background suppression. The adaptive iterative weighting with PELS smoothing effectively reduces noise and removes background disturbances. Case studies involving carbon fiber-reinforced polymer samples with inherent defects demonstrate the effectiveness of this post-processing approach
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