Your search
Results 2,120 resources
-
The Covid-19 pandemic evidenced the need Computer Aided Diagnostic Systems to analyze medical images, such as CT and MRI scans and X-rays, to assist specialists in disease diagnosis. CAD systems have been shown to be effective at detecting COVID-19 in chest X-ray and CT images, with some studies reporting high levels of accuracy and sensitivity. Moreover, it can also detect some diseases in patients who may not have symptoms, preventing the spread of the virus. There are some types of CAD systems, such as Machine and Deep Learning-based and Transfer learning-based. This chapter proposes a pipeline for feature extraction and classification of Covid-19 in X-ray images using transfer learning for feature extraction with VGG-16 CNN and machine learning classifiers. Five classifiers were evaluated: Accuracy, Specificity, Sensitivity, Geometric mean, and Area under the curve. The SVM Classifier presented the best performance metrics for Covid-19 classification, achieving 90% accuracy, 97.5% of Specificity, 82.5% of Sensitivity, 89.6% of Geometric mean, and 90% for the AUC metric. On the other hand, the Nearest Centroid (NC) classifier presented poor sensitivity and geometric mean results, achieving 33.9% and 54.07%, respectively.
-
The on-board identification of ore minerals during a cruise is often postponed until long after the cruise is over. During the M127 cruise, 21 cores with deep-seafloor sediments were recovered in the Trans-Atlantic Geotraverse (TAG) field along the Mid Atlantic Ridge (MAR). Sediments were analyzed on-board for physicochemical properties such as lightness (L*), pH and Eh. Selected samples were studied for mineral composition by X-ray powder diffraction (XRD). Based on XRD data, sediment samples were separated into high-, low- and non-carbonated. Removal of carbonates is a common technique in mineralogical studies in which HCl is used as the extraction agent. In the present study, sequential extraction was performed with sodium acetate buffer (pH 5.0) to remove carbonates. The ratio between the highest calcite XRD reflection in the original samples (Iorig) vs its XRD-reflection in samples after their treatment with the buffer (Itreat) was used as a quantitative parameter of calcite removal, as well as to identify minor minerals in carbonated samples (when Iorig/Itreat > 24). It was found that the lightness parameter (L*) showed a positive correlation with calcite XRD reflection in selected TAG samples, and this could be applied to the preliminary on-board determination of extraction steps with acetate buffer (pH 5.0) in carbonated sediment samples. The most abundant minerals detected in carbonated samples were quartz and Al- and Fe-rich clays. Other silicates were also detected (e.g., calcic plagioclase, montmorillonite, nontronite). In non-carbonated samples, Fe oxides and hydroxides (goethite and hematite, respectively) were detected. Pyrite was the dominant hydrothermal mineral and Cu sulfides (chalcopyrite, covellite) and hydrothermal Mn oxides (birnessite and todorokite) were mineral phases identified in few samples, whereas paratacamite was detected in the top 20 cm of the core. The present study demonstrates that portable XRD analysis makes it possible to characterize mineralogy at cored sites, in particular in both low- and high-carbonated samples, before the end of most cruises, thus enabling the quick modification of exploration strategies in light of new information as it becomes available in near-real time.
Explore
USJ Theses and Dissertations
-
Doctorate Theses
(66)
- Faculty of Art and Humanities (12)
- Faculty of Business and Law (14)
-
Faculty of Health Sciences
(2)
- Psychology (2)
- Faculty of Religious Studies and Philosophy (5)
- Institute for Data Engineering and Science (3)
-
Institute of Science and Environment
(10)
- Science (10)
-
School of Education
(20)
- Education (20)
-
Master Dissertations
(1,118)
-
Faculty of Arts and Humanities
(120)
- Architecture (8)
- Choral Conducting (10)
- Communication and Media (42)
- Design (24)
- History and Heritage Studies (28)
- Information System (3)
- Lusophone Studies in Linguistics and Literature (8)
- Faculty of Business and Law (499)
-
Faculty of Health Sciences
(206)
- Counselling and Psychotherapy (162)
- Organisational Psychology (23)
- Social Work (20)
-
Faculty of Religious Studies and Philosophy
(25)
- Philosophy (13)
- Religious Studies (12)
- Institute of Science and Environment (28)
-
School of Education
(243)
- Education (243)
-
Faculty of Arts and Humanities
(120)
Academic Units
- Domingos Lam Centre for Research in Education (1)
-
Faculty of Arts and Humanities
(261)
- Adérito Marcos (9)
- Álvaro Barbosa (32)
- Carlos Caires (15)
- Daniel Farinha (2)
- Denis Zuev (4)
- Filipa Martins de Abreu (11)
- Filipa Simões (2)
- Filipe Afonso (12)
- Francisco Vizeu Pinheiro (10)
- Gérald Estadieu (21)
- José Simões (40)
- Nuno Rocha (2)
- Nuno Soares (44)
- Olga Ng Ka Man, Sandra (7)
- Priscilla Roberts (4)
- Tania Marques (2)
-
Faculty of Business and Law
(205)
- Alessandro Lampo (21)
- Alexandre Lobo (90)
- Angelo Rafael (3)
- Douty Diakite (15)
- Emil Marques (2)
- Florence Lei (14)
- Ivan Arraut (17)
- Jenny Phillips (14)
- Sergio Gomes (2)
-
Faculty of Health Sciences
(40)
- Angus Kuok (17)
- Cynthia Leong (1)
- Helen Liu (1)
- Maria Rita Silva (1)
- Vitor Santos Teixeira (10)
-
Faculty of Religious Studies and Philosophy
(93)
- Andrew Leong (6)
- Cyril Law (11)
- Edmond Eh (6)
- Fausto Gomez (1)
- Franz Gassner (10)
- Jaroslaw Duraj (9)
- Judette Gallares (3)
- Stephen Morgan (18)
- Thomas Cai (4)
-
Institute for Data Engineering and Sciences
(29)
- George Du Wencai (23)
- Liang Shengbin (9)
-
Institute of Science and Environment
(122)
- Ágata Alveirinho Dias (39)
- Chan Shek Kiu (8)
- David Gonçalves (28)
- Karen Tagulao (17)
- Raquel Vasconcelos (11)
- Sara Cardoso (5)
- Shirley Siu (9)
- Thomas Lei (8)
- Wenhong Qiu (1)
-
Library
(3)
- Emily Chan (3)
-
Macau Ricci Institute
(17)
- Jaroslaw Duraj (4)
- Stephen Rothlin (13)
-
School of Education
(185)
- Elisa Monteiro (7)
- Hao Wu (5)
- Isabel Tchiang (2)
- Keith Morrison (85)
- Kiiko Ikegami (3)
- Miranda Chi Kuan Mak (11)
- Rochelle Ge (19)
- Susannah Sun (6)
Resource type
- Blog Post (3)
- Book (59)
- Book Section (128)
- Conference Paper (135)
- Document (4)
- Encyclopedia Article (1)
- Film (1)
- Journal Article (418)
- Magazine Article (17)
- Manuscript (1)
- Newspaper Article (34)
- Preprint (4)
- Presentation (63)
- Radio Broadcast (5)
- Report (62)
- Thesis (1,183)
- TV Broadcast (1)
- Web Page (1)
United Nations SDGs
- 01 - No Poverty (1)
- 02 - Zero Hunger (1)
- 03 - Good Health and Well-being (33)
- 04 - Quality Education (17)
- 05 - Gender Equality (1)
- 07 - Affordable and Clean Energy (3)
- 08 - Decent Work and Economic Growth (6)
- 09 - Industry, Innovation and Infrastructure (25)
- 10 - Reduced Inequalities (1)
- 11 - Sustainable Cities and Communities (11)
- 12 - Responsable Consumption and Production (6)
- 13 - Climate Action (8)
- 14 - Life Below Water (18)
- 15 - Life on Land (4)
- 16 - Peace, Justice and Strong Institutions (2)
- 17 - Partnerships for the Goals (1)
Cooperation
Student Research and Output
- Faculty of Business and Law (4)
-
School of Education
(4)
- Áine Ní Bhroin (1)
- Emily Chan (3)
Publication year
-
Between 2000 and 2024
- Between 2000 and 2009 (155)
- Between 2010 and 2019 (963)
- Between 2020 and 2024 (1,002)