1,720,959 research outputs found
Quantification of submerged seagrass total aboveground biomass for Malaysian coastal waters using remote sensing data
Full text linkMulti-species of seagrass forms dense benthic communities in the coastal clear (Case 1) and less clear water (Case 2) in Malaysia. There are two types of seagrass, i.e. intertidal and submerged, which can easily be found in Malaysia. Satellite remote sensing data is an effective tool to be used in many marine applications, including monitoring seagrass distribution at large area coverage. The emphasizes of this thesis is to determine the best two steps satellite-based approach for mapping submerged seagrass and quantifying aboveground biomass at Merambong area and Pulau Tinggi, Johor. Multi-platforms satellite data that has different data specifications have been used at both Case 1 (water dominated by phytoplankton) and Case 2 (water concentrated with water floating substances and sediments). The satellite data used for Merambong are GeoEye-1, Worldview-2, ALOS AVNIR-2, Landsat-8 OLI and Landsat-5 TM, while the satellite data for Pulau Tinggi are Worldview-2, ALOS AVNIR-2, Landsat-8 OLI and Landsat-5 TM. The robustness of seagrass detecting techniques, namely Depth Invariant Index (DII) and Bottom Reflectance Index (BRI) on remotely sensed data at different water clarity have been tested. Both techniques require measurement of radiance, deep-water radiance and ratio of attenuation coefficients while BRI needs few additional elements from nautical chart and tide calendar to attain information of the sea bottom depth during satellite passes. Ground truth data has intensively been collected at both study areas to validate and assess the finding of this study. Comparative assessment and analysis between both techniques revealed that BRI is best to be used on Landsat-8 OLI (93.2% user accuracy) in Case 2 water while (95.0% user accuracy) in Case 1 water to identify submerged seagrass. An empirical model has been developed to devise quantification of aboveground biomass and the temporal changes by associating insitu seagrass coverage data with BRI value on the satellite images. Submerged seagrass biomass quantification using remotely sensed data is feasible in Case 2 water at required scale and accuracy (>80%), depending on the field data sufficiency, technique and choice of satellite data. In conclusion, Landsat-8 OLI with 16-bits quantization level produces more accurate results than Worldview-2 and GeoEye-1. It is able to cover a large area of study, hence it is very useful for spatio-temporal seagrass biomass monitoring project by local policy makers and related agencies
Total aboveground biomass (TAGB) estimation using IFSAR: speckle noise effect on TAGB in tropical forest
No full textTotal Aboveground Biomass (TAGB) estimation is critically important to enhance understanding of dynamics of carbon fluxes between atmosphere and terrestrial ecosystem. For humid tropical forest, it is a challenging task for researchers due to complex canopy structure and predominant cloud cover. Optical sensors are only able to sense canopy crown. In contrast, radar technology is able to sense sub-canopy structure of the forest with penetration ability through the cloud for precise biomass estimation with validation from field data including diameter at breast height (DBH) of trees. This study is concerned about estimation of TAGB through the utilization of Interferometry Synthetic Aperture Radar (IFSAR). Based on this study, it is found that the stand parameters such as DBH and backscattered on IFSAR image has high correlation, R2=0.6411. The most suitable model for TAGB estimation on IFSAR is Chave Model with R2=0.9139. This study analyzes the impact brought by speckle noises on IFSAR image. It is found that filtering process has improves TAGB estimation about +30% using several filtering schemes especially Gamma filter for 11×11 window size. Using field data obtained from a primary tropical forest at Gerik, Perak, TAGBestimation can be validated and the assessment has been carried out
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
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