April 2024

TechTalk – Power Network Stability: A Network Science-based Approach

May 23, 2024 (Thursday) 4:30-5:30pm
Future power systems will need to accommodate a high penetration of renewables, new loads, and increased interconnections, which can make the system less resilient to changes and faults. However, traditional power system stability analysis methods may not be sufficient to ensure stable and robust operations in these new environments. To address this, network science is emerging as a promising area for developing new solutions. This seminar proposes a new framework for power system stability analysis that integrates network-based models with traditional power system theory. The focus will be on understanding how power network topology impacts the stability of the system, shedding new light on instability mechanisms.

TechTalk – Toward A Self-Chargeable Power Module for the Internet of Things

May 16, 2024 (Thursday) 4:30-5:30pm
In the era of the Internet of Things, portable electronic technology can help citizens to avail advanced features and characteristics in different facets of their daily life. These electronics powered by energy storage devices need regular recharging, but the increasing demand for continuous operation is driving research into new power supplies that can deliver stable electricity. One major development has been a conceptual shift away from grid supply charging toward self-charging. Triboelectric nanogenerators (TENGs) are emerging as a power supply for self-charged electronics due to their lightweight, simple fabrication, diversity in material selection, and high energy conversion efficiency, but the power output of TENGs needs to be trimmed to stably power the electronics. In this talk, I will address several strategies for power management of TENGs to achieve high-performing self-chargeable electronics, including current output boosting, ion-assisted contact electrification, and energy storage control.

HKAES TechTalk – Integration of AI and Wireless Networks for 6G Systems

May 21 2024 (Tuesday) 4:00-5:00pm
AI will be tightly integrated with wireless networks in future 6G wireless systems. On one hand, more and more AI applications will be running directly on mobile terminals for inferencing and training because dataset exists locally at mobile or IoT devices but large neural network models will be in the cloud. As such, wireless communication networks will be “in-the-loop” between mobile devices and the neural network models. it is important for future wireless networks to be optimised to support more efficient AI deployment. On the other hand, AI as a powerful tool can have huge potential to solve challenging problems in wireless communications design, resulting in better and more efficient wireless networks. There are lots of potential to deploy domain-specific AI design to implement challenging modules such as the physical layer and system designs in wireless systems. In this talk, we shall explore the integration of AI and future 6G wireless networks.

TechTalk – Greening the Slope: Revolutionizing Urban Water Management in Hilly Environments

May 14, 2024 (Tuesday) 3:30-4:30pm
Urban landscapes on slopes present unique challenges for managing stormwater. Traditional drainage systems often exacerbate other environmental problems, but sustainable drainage systems (SuDS) offer a nature-inspired solution. By mimicking natural processes, SuDS absorb, clean, and slowly release rainwater, effectively reducing stormwater and enhancing urban resilience. This talk explores innovative SuDS designs tailored for hilly environments. Findings highlight the effectiveness of integrating SuDS with existing infrastructure, particularly in collection-storage-release forms or terraced configurations. These showcase not only nearly complete water quantity control but also the potential of SuDS to transform urban water dynamics on slopes and emphasize their role in fostering sustainable cities.

Multimodal Dynamic and Unclonable Anticounterfeiting Using Robust Diamond Microparticles on Heterogeneous Substrate

Counterfeiting is a global menace endangering financial security, national safety, and public health. Traditional methods like watermarks and QR codes are vulnerable due to deterministic fabrication. Unbreakable security labels with physical unclonable functions (PUFs) offer a promising solution. PUFs leverage inherent randomness to create unique identifiers like fingerprints. Here, diamond-based PUFs, utilizing the stochastic nature of artificial diamond microparticles with silicon-vacancy (SiV) centers, offer a robust and unforgeable solution, providing a new frontier in anti-counterfeiting technology that is both durable and secure.

TechTalk – Healthcare Decision-Making: From Data to Solutions and Insights

May 09 2024 (Thursday) 4:30-5:30pm
Every day, numerous decisions must be made in healthcare systems, addressing a wide range of issues, including patient admissions, physician assignments, operating room scheduling, pharmaceutical inventory control, and ambulance dispatch. Conventionally, these decisions are made by experienced experts. However, human decision-makers may face challenges such as the unavailability of complete information, rapidly changing healthcare environments, personal biases, and prompt responses to medical emergence. Additionally, decision-makers often struggle to evaluate the effectiveness and possible consequences of their decisions.
This talk will introduce a set of scientific and systematic tools that leverage operations research techniques (originally developed to solve decision-making problems during World War II) and data collected in healthcare systems. The talk will begin with an overview of traditional healthcare decision-making approaches before delving into data-driven methodologies that have emerged in recent years. Subsequently, the speaker will share his experience over the years in tackling decision-making problems in healthcare systems in Hong Kong and the region, including emergency department patient flow modelling and optimization, medical appointment scheduling, vaccination strategies, and healthcare logistics. Finally, potential future directions for addressing healthcare decision-making challenges will be explored.
The supports by HKRGC (Refs: 27200419; 17204823; F-HKU704/22) and HMRF of the Health Bureau (Refs: 14202115; 21222881) for the projects to be presented in this talk are greatly acknowledged.

Young Scholar TechTalk – On Causality and the Upper Limit of Sound Absorption

April 30 2024 (Tuesday) 4:30-5:30pm
Sound absorption across a wide range of frequencies is a focus in contemporary acoustics. Recently, integral bounds of absorption or reflection coefficients were introduced as a guide of design optimization following the footsteps of electromagnetics, where integral relations were derived based on system causality considerations. This talk carefully examines the proper formulation of physical causality and its implications on the scattering properties of the system. Taking into consideration the effects of different physical boundary conditions and the bulk absorber material, a more generalized integral bound is derived. It becomes evident that, while the bound exists, it is governed by system stiffness rather than the causality constraint. By studying the effects of various approximations made during mathematical derivations, the physics of the bound is thoroughly discussed, and the limitations in utilizing integral bounds as reference for design optimization are highlighted. The findings are expected to have significant implications for the development of effective noise reduction strategies and the advancement of smart acoustic design.