19614 research outputs found
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Discovery and characterization of earthquakes on immature faults with InSAR
Get PDFFault structural maturity describes how fault zones evolve with incremental slip, and may control certain aspects of earthquake rupture behaviour. Immature faults are harder to identify and characterize than mature faults by virtue of their subtle to non-existent topographic and geophysical expressions, and thus pose distinct hazards and risks. Nonetheless, the advent of satellite-borne Interferometric Synthetic Aperture Radar (InSAR) surface deformation mapping has revolutionized our ability to characterize large earthquakes that occur on these hidden faults. By doing so, we can start to recognize common attributes to immature faults that may have important implications for seismic hazard. This is the central theme of this dissertation.
After introducing how InSAR works, I describe how to interpret surface deformation maps for various faulting styles. To explore relations between structural maturity and rupture behaviour, I then employ InSAR to characterize recent earthquakes along immature strike-slip faults in two contrasting tectonic settings: the Eastern California Shear Zone/Walker Lane of California and Nevada, USA, and the Shan Plateau in Laos, Thailand and Myanmar. The main foci are the 2020 Mw 6.5 Monte Cristo Range, Nevada earthquake and the 2019 Mw 6.2 Sainyabuli, Laos earthquake, respectively. In both cases, I tried to characterize the full complexity of the earthquakes by working with collaborators to incorporate independent seismological constraints.
We found certain rupture behaviours common to the Monte Cristo Range and Sainyabuli earthquakes that may be linked to fault maturity. Both mainshocks had short (∼20–30 km) fault lengths and pronounced (∼80–90%) shallow slip deficits (SSD) that may reflect off-fault deformation ∼5–10 km from the primary faults, consistent with relocated aftershocks. However, InSAR slip profile comparisons with other strike-slip earthquakes suggest that SSD is controlled more by earthquake magnitude than maturity, with smaller events having the greatest range in SSD and larger ones propagating to the surface with more consistency. The Monte Cristo Range earthquake also involved an unusual configuration of crossing faults, likely due to the early evolution stage of the host fault zone.
The limited geomorphic expression along modelled faults of the Monte Cristo Range and Sainyabuli events raises an alarming concern for seismic hazard assessment (SHA). Since immature faults are hard to map, they are often overlooked in hazard calculations. However, SHA practitioners may benefit from knowledge of rupture geometries and behaviours provided by observational studies like this dissertation, to help define seismic sources and select appropriate ground motion models for regional and site-specific SHA.Graduat
Emotion detection with data fusion
Get PDFThis report explores the performance of three machine learning models — SVM with SGDClassifier, Gradient Boosting, and XGBoost — in detecting emotions using data fusion techniques. Early Fusion was chosen for integrating features due to its simplicity and reliable performance. The study employs the MELD dataset, which combines text, audio, and visual data from over 1,300 dialogues and 13,000 utterances in the “Friends” TV show. This dataset provides a unique multimodal approach to understanding emotions in conversational contexts, making it ideal for emotion recognition tasks.
Evaluation metrics for the models included accuracy, F1-score, precision, recall, and AUCROC, calculated over multiple training iterations. By comparing the performance of these models on a comprehensive, multimodal dataset, this study meets the growing demand for accurate emotion detection in conversational AI. XGBoost demonstrated high and consistent performance on the MELD dataset; however, its effectiveness may vary under different conditions or datasets. SVM with SGDClassifier achieved the widest accuracy range, though less stable on nuanced emotions. Gradient Boosting delivered consistently strong AUC-ROC values but required full retraining with each data update, affecting its adaptability.
Overall, while XGBoost and SVM delivered good performance, their accuracy was subject to fluctuations across iterations. Gradient Boosting consistently showed strong AUC-ROC values, but its disadvantage is the need to completely retrain the model when new data is added, which reduces efficiency.Graduat
StretchVADER – A Rule-based Technique to Improve Sentiment Intensity Detection using Stretched Words and Fine-Grained Sentiment Analysis
No full textWatching a horror movie and someone shouts “HEEEELLLPPPPPPPPP” or someone replies to your joke with a huge “HAHAHAHAHAHAHAHAHAHAHA” is known as word stretching. Word stretching is not only an integral part of spoken language but is also found in many texts. Though it is very rare in formal writing, it is frequently used on social media. Word stretching emphasizes the meaning of the underlying word, changes the context and impacts the sentiment intensity of the sentence.
In this work, a rule-based fine-grained approach to sentiment analysis named StretchVADER is introduced that extends the capabilities of the rule-based approach called VADER. StretchVADER detects sentiment intensity using textual features such as stretched words and smileys by calculating a StretchVADER Score (SVS). This score is also used to label the dataset. It has been observed that many tweets contain stretched words and smileys, e.g. 28.5% in a randomly extracted dataset from Twitter. A dataset is also generated and annotated using SVS which contains detailed features related to stretched words and smileys. Finally, Machine Learning (ML) models are evaluated using two different data encoding techniques, e.g. TF-IDF and Word2Vec. The results obtained show that the XGBoost algorithm with 1500 gradient-boosted trees and TF-IDF data encoding achieved a higher accuracy, precision, recall and F1-score than the other ML models, i.e. 91.24%, 91.11%, 91.24% and 91.08%, respectively.Graduat
UVic Convocation June 12, 2024 – 2:00 pm
No full textStudents from the Division of Continuing Studies.UndergraduateUnreviewe
Enabling DC Field-Directed Chaining of Nanowires for Microelectronic Applications
No full textSolar cells, light-emitting diodes, small-scale sensors, and large-area displays are examples of devices that benefit from the use of transparent conductive electrodes (TCEs). Indium tin oxide (ITO) is the most widely used transparent electrode material, exhibiting both high transparency and conductivity. However, the low concentration of indium in its ores makes it an expensive material to process. Indium price fluctuations lead to unsteadiness in manufacturing costs. Moreover, the fragile nature of ITO limits its usefulness in the fabrication of flexible electrodes. To address these issues, transparent conductive oxides and polymers, carbon nanotubes, graphene, and metal nanowires are being explored as potential candidates to replace ITO as the primary transparent conductor. Nanowire (NW) networks offer several advantages over ITO in terms of low cost, ease of fabrication, and flexibility.
Large area coverage with ordered NW chains is challenging as it is difficult to control an electric field and its gradient in large electrode gaps. Electric field-directed chaining in a nanowire (NW) suspension was previously demonstrated as a simple and cost-effective process for large area coverage, with high conductivity and transparency. However, generating an effective dielectrophoretic (DEP) force for the desired NW assembly requires a high frequency to overcome the charge screening effect due to the polarity of water or alcohol, commonly used as suspension media. This requirement is a major limitation. High frequency can also generate harmful electromagnetic radiation as well as power loss in wiring. Moreover, the magnitude of the electric field and DEP force decreases sharply in the region away from the electrodes. Therefore, more NWs are bunched in the vicinity of electrodes, while at distant locations NWs are observed to form curls and branches, producing poorly aligned chains.
Here we present the use of squalane (C30H62), a non-polar, non-toxic, unreactive, viscous organic liquid, for the suspension of NWs in an electric field-directed assembly. Our theoretical analysis suggested that squalane could reduce voltage drop at the electrode, enabling adequate DEP force for chaining. Moreover, this could be done at a lower frequency because of the low electrical conductivity and dielectric constant of squalane. Additionally, we may expect that the high viscosity of squalane will suppress the electroosmotic flow of the medium and Brownian motion of NWs, thereby facilitating the chaining process. Experiments have been performed with both polar and non-polar suspension media to observe their effectiveness in DEP-assisted NW chaining. Our experiments confirmed that squalane does generate NW chains at low-frequency AC (and down to DC) fields, whereas conventional polar suspension media require substantially higher frequency. Finally, a magneto-electro-kinetic model has been developed to explore how combining an external magnetic field with the electric field may enable better control of the NW alignment far from the electrodes.Graduate2024-11-1
Analyzing patterns of service utilization using graph topology to understand the dynamic of the engagement of patients with complex problems with health services
Get PDFBackground: Providing care to persons with complex problems is inherently difficult due to several factors, including the impacts of proximal determinants of health, treatment response, the natural emergence of comorbidities, and service system capacity to provide timely required services. Providing visibility into the dynamics of patients’ engagement can help to optimize care for patients with complex problems. Method: In a previous work, graph machine learning and NLP methods were used to model the products of service system dynamics as atemporal entities, using a data model that collapsed patient encounter events across time. In this paper, the order of events is put back into the data model to provide topological depictions of the dynamics that are embodied in patients’ movement across a complex healthcare system. Result: The results show that directed graphs are well suited to the task of depicting the way that the diverse components of the system are functionally coupled—or remain disconnected—by patient journeys. Conclusion: By setting the resolution on the graph topology visualization, important characteristics can be highlighted, including highly prevalent repeating sequences of service events readily interpretable by clinical subject matter experts. Moreover, this methodology provides a first step in addressing the challenge of locating potential operational problems for patients with complex issues engaging with a complex healthcare service system.FacultyReviewe
Performing the Intercultural Archive: Lina de Guevara's Puente Theatre in Special Collections
Get PDFThis research interrogates the play “Storytelling Our Lives” (1998), which was produced by the local, Latin American theatre company, Puente Theatre, and is now in the Lina de Guevara fonds in the UVic Libraries Special Collections. This interrogation concludes that, by sourcing dramatic content from the lived experiences of immigrant women in Victoria, the dramaturgical process of this play resembles the accessioning process of traditional archives. Furthermore, this play seems to have generated a sense of cultural unity in its audiences, bridging wildly diverse backgrounds, distinctly due to its inclusion of community members. Archivists might learn from this study how performance constitutes an unlikely archive of marginalised lived experiences and cultures, and how the efficacy of this unlikely archive depends on its ephemeral nature. Theatre practitioners might better understand how including community members in a professional theatre production bridges cultural gaps in diverse audiences, and thus advocates for the function of “local” theatre. I deploy a method intoned by archival theory, Ric Knowles’ studies of intercultural performance in Canada, and Holledge and Tompkins’ definition of interculturalism.Jamie Cassels Undergraduate Research Awards (JCURA)UndergraduateReviewe
VILSC 2022 Opening and Keynote
No full textA recording of the opening of the 2022 Vancouver Island Library Staff Conference, including a Welcome and Blessing from Tsartlip Elder and UVic Elder in Residence May Sam and a keynote talk by Shelagh Rogers and Leslie Weir.FacultyUnreviewe
Silkscreen August 2024
No full textᐃ ᓈᓈ ᑲ ᒋ ᔕ ᑲ ᓇᔥ ᐊ ᔐ ᑲ ᐸᐧ ᐁ ᐃ ᒥ ᓈᐧ ᐸ ᓇ ᓴ ᑭ ᔑᓇ ᒧᐧ ᐃᐧ ᐃValerie Kuehne Undergraduate Research Awards (VKURA)UndergraduateReviewe