1,720,956 research outputs found
Settlement type classification using aerial images.
Full text linkM. Sc. University of KwaZulu-Natal, Durban 2014.In metropolitan and urban areas, the problems relating to rapid transformations that are taking
place in terms of land cover and land use are now very pronounced, e.g., the rapid increase and
unpredictable spread of formal and informal physical infrastructure. As a result, the availability
of detailed, timely information on urban areas is of considerable importance both to the management
of current urban activities and to forward planning. Remote sensing sources can make
a vital contribution in this context, since they provide regular and recurring data from a single,
consistent source. Pattern recognition techniques have been demonstrated to be effective in distinguishing
and classifying human settlements. However, these methods are not ideal as they
perform poorly when presented with imagery of the same area acquired at different dates. The
poor generalization ability is mainly caused by large off-nadir viewing angles which produce
image pairs with different viewing- and illumination-geometries. Classification performance is
also decreased by differences in shadow length and orientation.
The objective of this research is to improve the generalisation ability of the automated classification
of human settlements using only remote sensing data over urban areas. The multiresolution
local binary patterns (LBPs) algorithm, extended with an orthogonal variance measure
for measuring local contrast features (i.e., the extended LBP) has been shown to excel at texture
classification tasks. To minimize the viewing- and illumination-geometry effects and improve
settlement classification, the extended LBP was applied to high spatial resolution panchromatic
aerial images. The addition of a contrast component to the LBP features does not directly affect
the desired invariance to shadow orientation and length, but it is expected that the richer features
will nevertheless improve settlement classification accuracy.
The extended LBP method was evaluated using a support vector machine (SVM) classifier
for cross-date (training and test images of the same area acquired at different dates) and samedate
analysis. For comparable results, LBPs without contrast features were also evaluated. The
results showed the extended LBP to have a strong spatial and temporal generalisation ability for
classifying settlements of aerial images, when compared to its counterpart. From this research,
we can conclude that the extended LBP’s additional contrast features can improve overall settlement
type classification accuracy and generalisation ability
A novel framework for monitoring oil spill from moving vessels using synthetic aperture radar
Full text linkThesis (PhD)--University of Pretoria, 2018.Operational discharges of oil from vessels, whether accidental or deliberate, are a growing concern as
the levels of maritime traffic increase. Oil tankers and other kinds of ships are among the suspected
offenders of illegal discharges. The international legislation contains minor and well-defined exceptions
related to ocean areas (internal waters, marine protected areas, MARPOL “special” areas, territorial
seas or exclusive economic zones). These areas often determine whether an action is considered legal
or not and define the rights and obligations, including law enforcement obligations.
Synthetic aperture radar (SAR) is the most used remote sensing tool for monitoring oil pollution over
vast ocean areas. SAR is an active microwave RS sensor capable of taking measurements day or night
and almost independently from atmospheric conditions. Manual oil spill detection in a SAR image is
ordinarily done by a trained human interpreter who visually inspects SAR images for any possible
spills. However, manual inspection can be time-consuming, biased, inconsistent and subjective. A
faster and more robust alternative is to use automated image processing and machine learning methods.
The current automated oil detection methods, however, are still not ideal and there is still a need for
improvement. Also, data costs have resulted in limited studies on oil spill detection in African oceans.
The launch of several Sentinel missions with SAR sensors has considerably improved coverage and accessibility of data over African oceans. The goal of the study is to develop an automated detection
of oil spill discharges from vessels in African seas using the freely available Sentinel SAR data.
A novel oil spill detection framework that can detect possible oil spill candidates and remove unwanted
detections (i.e., false positives) was proposed. The framework used a novel linear dark spot detection
algorithm and an improved oil spill discrimination process. The linear detection process used a
segmentation-based algorithm to isolate linear dark spots (potential oil spills) from other features in
the image. The process involved a more efficient feature selection and classification process. The
proposed linear detection algorithm was evaluated for detection accuracy and compared to other
segmentation-based oil spill detection algorithms, including state-of-the-art oil spill detection methods.
The results demonstrated the proposed approach to be a more efficient and robust linear dark spot
detection method. An improved discrimination process was presented to reduce false detections
from a segmentation-based algorithm. The selection of relevant oil spill features depends on many
factors which could influence the accuracy of the classification task. Automated features selection
methods were thus considered to improve the discrimination process. Using feature selection, the most
significant oil spill features with minimum variations were determined. The significant features were
used as input vectors to classify oil spill events from moving vessels. An optimised Gradient Boosting
Tree Classifier (GBT) was used for the classification task.
The proposed novel framework showed promising results for monitoring oil spill from moving vessels
using SAR in African oceans on a regular basis. Future work includes adding a confidence measure
and alert level estimation. The system will incorporate ancillary information such as the oil spill source
and the sensitivity of the polluted area to measure environmental impact.Council for Scientific and Industrial Research (CSIR), Pretoria, South AfricaElectrical, Electronic and Computer EngineeringPhDUnrestricte
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
Systems and architectural support for open data principles : a marine earth observation perspective
Full text linkThe GMES and Africa, MarCOSIO project, promotes the sustainable management of marine resources, improves marine governance,
and stimulates the growth of the blue economy in the Southern African and Indian ocean region. Because of its mandate,
a wide range of applications, and regional view that incorporates eight countries, the MarCOSIO Information Management System
adopts and continues to strive towards implementation of open data principles. This paper presents considerations of the Mar-
COSIO information management systems towards the adoption and implementation of open data, FAIR and TRUST principles, to
ensure the sustainability of its services and offerings. The implementation of the system is evaluated against criteria that assess the
alignment to FAIR, TRUST, and Open Data principles. An assessment of the results shows that the system aligns closely, though
not fully, with the FAIR and TRUST principles. This is mainly due to the use of reputable open-source tools that implement wellknown
and accepted standards. On the basis of the services provided, the system cannot be fully open, as in some cases the need
for security outweighs the openness. This is specifically true for cases where there is a need to protect personal information, and
public disclosures are prohibited by law. The use of open data from the European Commission has allowed the rapid development
of regionally relevant solutions that, in turn, have remarkably improved decision making in promoting the protection and growth of
the ocean economy. It is one of the goals of the open data directive to increase public participation in the achievement of economic
growth.https://www.isprs.org/publications/archives.aspxam2024Geography, Geoinformatics and MeteorologyNon
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