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13 results on '"Leung, Tsz Yan"'

1. Towards a Simple Framework of Skill Transfer Learning for Robotic Ultrasound-guidance Procedures

Author

Leung, Tsz Yan and Xochicale, Miguel

Subjects
Computer Science - Robotics, Computer Science - Artificial Intelligence, Computer Science - Hardware Architecture, Electrical Engineering and Systems Science - Image and Video Processing, Physics - Medical Physics
Abstract

In this paper, we present a simple framework of skill transfer learning for robotic ultrasound-guidance procedures. We briefly review challenges in skill transfer learning for robotic ultrasound-guidance procedures. We then identify the need of appropriate sampling techniques, computationally efficient neural networks models that lead to the proposal of a simple framework of skill transfer learning for real-time applications in robotic ultrasound-guidance procedures. We present pilot experiments from two participants (one experienced clinician and one non-clinician) looking for an optimal scanning plane of the four-chamber cardiac view from a fetal phantom. We analysed ultrasound image frames, time series of texture image features and quaternions and found that the experienced clinician performed the procedure in a quicker and smoother way compared to lengthy and non-constant movements from non-clinicians. For future work, we pointed out the need of pruned and quantised neural network models for real-time applications in robotic ultrasound-guidance procedure. The resources to reproduce this work are available at \url{https://github.com/mxochicale/rami-icra2023}., Comment: 2 pages, 2 figures and code and demo data

Published
2023

2. Weather predictability : some theoretical considerations

Author

Leung, Tsz Yan

Abstract

The chaotic nature of atmospheric dynamics presents a central challenge to the accurate prediction of future weather. It is a well-known fact that the predictability of instantaneous weather is inherently limited to about two weeks, beyond which skilful prediction is impossible no matter how small the initial error is. This study seeks to advance the knowledge related to the limited predictability by addressing three theoretical topics. The first topic concerns the mathematical origins of the predictability barrier. In a simplified context, what appears to be a contradiction between the finite-time limit and the regularity of the governing equations is reconciled through understanding the practical role of the slope of the energy spectrum in the latter. The next topic explores the properties of error growth under the hybrid k −3 - k − 5 3 energy spectrum that approximates the atmosphere. With the aid of simplified turbulence models, the synoptic-scale k −3 range is found to substantially dampen the fast error growth characteristic of a k − 5 3 spectrum in the first decade of wavenumbers in the mesoscale range, so that the fast growth may only emerge when global numerical weather prediction models begin to resolve scales on the order of a few kilometres. The final topic focusses on the relationship between metrics that quantify error growth and predictability. Two popular metrics, namely the Continuous Ranked Probability Score and the root-mean-square error, are found to be mathematically related under certain conditions. Simulated results show that the relationship approximately holds in idealised turbulent environments despite the required conditions not being fully met. This study demonstrates that simple models can often be useful in identifying key mechanisms of error growth that lead to the limit of predictability. Future work involving simple models is encouraged to substantiate such understanding further.

Published
2020
Full Text
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11. Photocatalytic disinfection towards freshwater and marine bacteria using fluorescent light.

Author

Leung, Tsz Yan., Chinese University of Hong Kong Graduate School. Division of Biology., Leung, Tsz Yan., and Chinese University of Hong Kong Graduate School. Division of Biology.

Abstract

Leung, Tsz Yan., Thesis (M.Phil.)--Chinese University of Hong Kong, 2008., Includes bibliographical references (leaves 132-146)., s in English and Chinese., Acknowledgements --- p.i, p.ii, Table of Contents --- p.vii, List of Figures --- p.xii, List of Plates --- p.xiv, List of Tables --- p.xvii, Abbreviations --- p.xviii, Equations --- p.xxi, Chapter 1. --- Introduction --- p.1, Chapter 1.1 --- Water crisis and water disinfection --- p.1, Chapter 1.2 --- Common disinfection methods --- p.2, Chapter 1.2.1 --- Chlorination --- p.2, Chapter 1.2.2 --- Ozonation --- p.4, Chapter 1.2.3 --- Ultraviolet-C (UV-C) irradiation --- p.6, Chapter 1.2.4 --- Solar disinfection (SODIS) --- p.7, Chapter 1.2.5 --- Mixed disinfectants --- p.9, Chapter 1.2.6 --- Other disinfection methods --- p.10, Chapter 1.3 --- Advanced oxidation processes (AOPs) --- p.11, Chapter 1.4 --- Photocatalytic oxidation (PCO) --- p.13, Chapter 1.4.1 --- Understanding of PCO process --- p.15, Chapter 1.4.2 --- Proposed disinfection mechanism of PCO --- p.18, Chapter 1.4.3 --- Titanium dioxide (Ti02) photocatalyst --- p.21, Chapter 1.4.4 --- Irradiation sources --- p.22, Chapter 1.4.5 --- Bacterial species --- p.23, Chapter 1.4.5.1 --- Escherichia coli K12 --- p.23, Chapter 1.4.5.2 --- Shigella sonnei --- p.24, Chapter 1.4.5.3 --- Alteromonas alvinellae --- p.25, Chapter 1.4.5.4 --- Photobacterium phosphoreum --- p.26, Chapter 1.4.6 --- Bacterial defense mechanism towards oxidative stress --- p.27, Chapter 1.4.6.1 --- Superoxide dismutase (SOD) activity --- p.28, Chapter 1.4.6.2 --- Catalase (CAT) activity --- p.29, Chapter 1.4.6.3 --- Fatty acid (FA) profile --- p.30, Chapter 1.4.7 --- Significance of the project --- p.31, Chapter 2. --- Objectives --- p.34, Chapter 3. --- Material and Methods --- p.36, Chapter 3.1 --- Chemicals --- p.36, Chapter 3.2 --- Screening of freshwater and marine bacterial culture --- p.36, Chapter 3.3 --- Photocatalytic reaction --- p.39, Chapter 3.3.1 --- Preparation of reaction mixture --- p.39, Chapter 3.3.2 --- Preparation of bacterial culture --- p.39, Chapter 3.3.3 --- Photocatalytic reactor --- p.41, Chapter 3.3.4 --- PCO disinfection reaction --- p.42, Chapter 3.3.4.1 --- Effect of initial pH --- p.44, Chapter 3.3.4.2 --- Effect of reaction temperature --- p.45, Chapter 3.3.4.3 --- Effect of growth phases --- p.45, Chapter 3.4 --- Measurement of superoxide dismutase (SOD) activity --- p.47, Chapter 3.5 --- Measurement of catalase (CAT) activity --- p.49, Chapter 3.6 --- Fatty acid (FA) profile --- p.50, Chapter 3.7 --- Bacterial regrowth test --- p.51, Chapter 3.8 --- Atomic absorption spectrophotometry (AAS) --- p.52, Chapter 3.9 --- Total organic carbon (TOC) analysis --- p.53, Chapter 3.10 --- Chlorination --- p.55, Chapter 3.11 --- UV-C irradiation --- p.56, Chapter 3.12 --- Transmission electron microscopy (TEM) --- p.56, Chapter 4. --- Results --- p.60, Chapter 4.1 --- Screening of UV-A resistant freshwater and marine bacteria --- p.60, Chapter 4.2 --- Control experiments --- p.62, Chapter 4.3 --- Treatment experiments --- p.65, Chapter 4.3.1 --- UV-A irradiation from lamps --- p.65, Chapter 4.3.2 --- Fluorescent light from fluorescent lamps --- p.65, Chapter 4.3.3 --- Effect of initial pH --- p.67, Chapter 4.3.4 --- Effect of reaction temperature --- p.70, Chapter 4.3.5 --- Effect of growth phases --- p.70, Chapter 4.4 --- Factors affecting bacterial sensitivity towards PCO --- p.73, Chapter 4.4.1 --- Superoxide dismutase (SOD) and catalase (CAT) activities --- p.73, Chapter 4.4.2 --- Superoxide dismutase (SOD) and catalase (CAT) induction --- p.74, Chapter 4.4.3 --- Fatty acid (FA) profile --- p.75, Chapter 4.5 --- Bacterial regrowth test --- p.78, Chapter 4.6 --- Disinfection mechanisms of fluorescent light-driven photocatalysis --- p.79, Chapter 4.6.1 --- Atomic absorption spectrophotometry (AAS) --- p.79, Chapter 4.6.2 --- Total organic carbon (TOC) analysis --- p.81, Chapter 4.6.3 --- Transmission electron microscopy (TEM) --- p.83, Chapter 4.7 --- Chlorination --- p.89, Chapter 4.7.1 --- Disinfection efficiency --- p.89, Chapter 4.7.2 --- Transmission electron microscopy (TEM) --- p.92, Chapter 4.8 --- UV-C irradiation --- p.96, Chapter 4.8.1 --- Disinfection efficiency --- p.96, Chapter 4.8.2 --- Transmission electron microscopy (TEM) --- p.96, Chapter 5. --- Discussions --- p.103, Chapter 5.1 --- Screening of UV-A resistant freshwater and marine bacteria --- p.103, Chapter 5.2 --- Comparison of PCO coupled with UV-A lamps and fluorescent lamps --- p.103, Chapter 5.3 --- Effect of initial pH --- p.105, Chapter 5.4 --- Effect of reaction temperature --- p.106, Chapter 5.5 --- Effect of growth phases --- p.107, Chapter 5.6 --- Factors affecting bacterial sensitivity towards PCO --- p.108, Chapter 5.6.1 --- Superoxide dismutase (SOD) and catalase (CAT) activities --- p.108, Chapter 5.6.2 --- Superoxide dismutase (SOD) and catalase (CAT) induction --- p.110, Chapter 5.6.3 --- Fatty acid (FA) profile --- p.110, Chapter 5.6.4 --- Cell wall structure --- p.112, Chapter 5.6.5 --- Bacterial size --- p.114, Chapter 5.6.6 --- Other possible factors --- p.114, Chapter 5.7 --- Bacterial regrowth test --- p.115, Chapter 5.8 --- Disinfection mechanisms of fluorescent light-driven photocatalysis --- p.116, Chapter 5.8.1 --- Atomic absorption spectrophotometry (AAS) --- p.116, Chapter 5.8.2 --- Total organic carbon (TOC) analysis --- p.117, Chapter 5.8.3 --- Transmission electron microscopy (TEM) --- p.118, Chapter 5.9 --- Chlorination --- p.122, Chapter 5.9.1 --- Disinfection efficiency --- p.122, Chapter 5.9.2 --- Transmission electron microscopy (TEM) --- p.122, Chapter 5.10 --- UV-C irradiation --- p.123, Chapter 5.10.1 --- Disinfection efficiency --- p.123, Chapter 5.10.2 --- Transmission electron microscopy (TEM) --- p.124, Chapter 5.11 --- Comparisons of three disinfection methods --- p.124, Chapter 6. --- Conclusions --- p.126, Chapter 7. --- References --- p.132, http://library.cuhk.edu.hk/record=b5893609, Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Published
2008

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