Oversea speaker

TechTalk – Doing the Right Thing for the Wrong Reason: How a Vision for Ubiquitous Computing Can Be Reconciled to Have Better Impact

November 27 2023 (Monday) 4:00-5:00pm
Professor Gregory Abowd have been speaking and writing about the idea of an Internet of Materials (IoM) for nearly a decade. It started as a way to rethink Mark Weiser’s vision of ubiquitous computing in a more modern context, with the same hopeful zeal that Weiser presented in his writings from the late 1980s and early 1990’s. Professor Abowd will summarize how that re-interpretation has inspired his work, and the work of a growing community, for nearly a decade. From those involved in the fundamental understanding of computation to those involved in the practical development and deployment of computation, the future seems bright. We are moving towards a world of increased ubiquity of computation. There appears to be no end in sight for the increased ubiquity of all things computational. From a technical perspective, this is wonderful. More recently, professor Abowd have been forced to think about this vision through a different lens. How we justify any new vision of a technological future must be better grounded in the human motivation and potential impact. After explaining the “successes” of IoM, he will explain why he has fallen far short of a compelling motivation. But there are more compelling motivations, having to do with health, usable security and privacy, and, most importantly, sustainability. We MUST begin questioning a lot of the assumptions on how to make, operate, and dispose of computational objects. IoM is no longer a journey for a hopeful “visionary” to play out his fanciful predictions for the future. It is a mandate to address the fundamental hazards of our current trajectory towards ubiquitous computing.

TechTalk – Live “Street View” of Intracellular Organelles’ Interactions

November 13 2023 (Monday) 3:00-4:00pm
The number of colors in fluorescence microscopy is far less than the types of intracellular compartments. I will present our recent progress in super resolution imaging and deep convolutional neuronal networks to segment 15 subcellular structures. This approach bypasses the limitations of multi-color imaging, accelerates the imaging speed by one order of magnitude, and can accurately segment vesicle organelles with similar shapes and sizes. The super-resolution advantages were demonstrated in resolving the 3D anatomic nanostructures at different mitotic phases and tracking the fast dynamic interactions among nine intracellular compartments in live cell. We show transfer learning ability of our networks among different microscopes, different cell types, and even complexed system of living tissues.

TechTalk – Subsurface Technologies to Support the Energy Transition

October 12 2023 (Thursday) 3-4pm
To avoid catastrophic consequences of climate change, our current carbon-emitting energy infrastructure needs to be replaced with an energy system free from atmospheric carbon emissions. The enormous scale of this energy transition requires multiple energy sources to be developed, including carbon-free wind, solar, geothermal, and nuclear as well as fossil-fuel-based systems where the carbon dioxide from the waste stream is captured and stored securely in deep subsurface geologic formations, in a technology known as Carbon Capture and Storage, or CCS. Subsurface geologic formations are also likely to be used to provide short-term storage for energy-carrying fluids like hydrogen and natural gas, making the subsurface environment critical to the energy transition. In this talk, I will discuss practical computational approaches to analyze geological storage systems as well as economic and political issues associated with CCS. I will also briefly discuss basic climate change facts, as part of a proposed general curriculum for Environmental Literacy.

TechTalk – Quantitative Predictive Theories through Integration of Quantum, Statistical, and Irreversible Thermodynamics

August 28, 2023 (Monday) 2-3pm
Thermodynamics is a science concerning the state of a system, whether it is stable, metastable, or unstable. Its derivatives to natural variables give fundamental physico-chemical properties of the system. It is historically divided into four categories: equilibrium thermodynamics by Gibbs, statistical thermodynamics by Gibbs and Landau, irreversible thermodynamics by Onsager and Prigogine, and quantum mechanics. The development of density function theory (DFT) enabled the quantitative prediction of properties of the ground state of a system from quantum mechanics. Their integration into predictive theories will be discussed in this presentation along with future perspectives. It will be shown that the zentropy theory combines the bottom-up DFT predictions with the revised top-down statistical thermodynamics, while the theory of cross phenomena keeps the entropy production due to irreversible processes in the combine law of thermodynamics to revise the Onsager flux equations. The zentropy theory is capable of quantitatively predicting free energy landscape, singularity and emergent divergences of properties at critical point free of parameters, while the theory of cross phenomena can predict the coefficients of internal processes between non-conjugate variables.

TechTalk – Theoretical Concepts and Innovative Laboratory Techniques for Estimating the Effective Permeability of Rocks: Applications to the Longyou Claystone

The Longyou Caves represent an important historical site in China that has undergone periodic water level changes over several centuries. The ground water flow through the intact rock and fractures is an important factor in the geotechnical assessment of the site. The Environmental Geomechanics Laboratory at McGill University has focused on the development of innovative theoretical approaches and experimental facilities for wide range of rocks including Indiana Limestone, the Cobourg Limestone, the Vermont Granite and the Lac du Bonnet Granite, using both steady state and transient techniques. In this Teck Talk, Professor Selvadurai will present a range of experimental techniques, their theoretical interpretations that can be used to estimate of fluid transport processes through intact rocks that can be described by Darcy’s law. The theoretical and experimental techniques are used to determine the intact permeability of Longyou claystone recovered from the site.

TechTalk – Organic Neuromorphic Materials and Devices

By integrating sensing, memory and processing functionalities, biological nervous systems are energy and area efficient. Emulating such capabilities in artificial systems is, however, challenging and is limited by the device heterogeneity of sensing and processing cores., Here, we present a universal solution to simultaneously perform multi-modal sensing, memory and processing using organic electrochemical transistors. The device has a vertical traverse architecture and a crystalline–amorphous channel that can be selectively doped by ions to enable two reconfigurable modes: volatile receptor and non-volatile synapse. As a volatile receptor, the device is capable of multi-modal sensing, and as a non-volatile synapse, it is capable of 10-bit analogue states, low switching stochasticity and good state retention. Homogeneous integration of such devices enables functions such as conditioned reflex and real-time cardiac disease diagnose via reservoir computing, illustrating the promise for future edge AI hardware.

TechTalk – AI for Science: From Scientific Discoveries to Platform Engineering

Artificial Intelligence (AI) has been revolutionizing numerous fields within science and engineering, giving rise to “AI for Science” – a new paradigm for both academia and industry. In this seminar, we will explore how AI algorithms and tools empower researchers to tackle intricate scientific challenges, strengthen collaboration, and expedite the discovery process. We will also envision the future of this field in the era of cloud-native infrastructures and large language models, emphasizing the crucial role of platform engineering in nurturing the growth and development of the entire scientific community. Lastly, we will provide examples to illustrate the potential appearance of such platforms and discuss the path towards their realization.

TechTalk – Schwarz Crystal Structure in Polycrystalline Metals with Extremely Fine Grains

Metals usually exist in form of polycrystalline solids, in which the networks of disordered grain boundaries tend to get eliminated through grain coarsening upon heating or straining, or to transform into metastable amorphous states when the grains are small enough. This is why nano-grained structures in metals are much more unstable relative to their coarse-grained counterparts. Through experiments and molecular dynamic simulations, we recently discovered a novel metastable structure in metals with grains of few nanometers in size, namely Schwarz crystal structure. The GB-network of the metal is characterized by 3D minimal interfaces structure with a zero-mean-curvature constrained by twin boundaries. The unique structure is thermally stable against grain coarsening at temperatures close to the equilibrium melting point and exhibits a hardness in vicinity of the theoretical value. The across-boundary diffusion is so effectively suppressed that the diffusion-controlled processes such as intermetallic precipitation are inhibited. In this presentation, Professor Ke Lu will introduce the formation process, structure characteristics, and some properties of the Schwarz crystal structures in a number of pure metals and alloys.

TechTalk – Rational Approach for Seismic Analysis of Long Underground Tunnels Based on 2.5D Formulation

This lecture presents a rational procedure for the seismic analysis of underground tunnels using recorded free-field earthquakes based on the 2.5D finite/infinite element approach. The near and far fields of the half space are modeled by finite and infinite elements, respectively. Using the 1D wave theory, the nodal force and displacement on the near-field boundary are computed for each spectral frequency of the earthquake. Then, equivalent seismic forces are computed for the near-field boundary for the imposition of earthquake spectrum. By assuming the soil-tunnel system to be uniform along the tunnel axis, the 2.5D approach adopted can duly account for the wave transmission along the tunnel axis, which reduces to the 2D case for infinite transmission velocity. The horizontal and vertical components of the 1999 Chi-Chi Earthquake (TCU068) are adopted as the free-field motions in the numerical analysis. The maximal stresses and distribution patterns of the tunnel section under the P- and SV-waves are thoroughly studied by the 2.5D and 2D approaches, which should prove useful to the design of underground tunnels. Comments on the idea to extend the present approach to include the effect of overlying water, such as the case for the sites below reservoirs, rivers, or sea, will also be pointed out.

TechTalk – The Metaverse Heatwave

It may not be an overstatement that most of us using the internet has heard of metaverse. The term ‘metaverse’ has seen to stir up global hype for business opportunities and fantasy for mankind, if not became the Oxford Word of the Year 2022 – a word reflecting the ethos, mood, or preoccupations, one that has potential of lasting cultural significance. Metaverse describes a virtual reality environment in which users interact with one another’s avatars and their surroundings in an immersive way. We are going to explore what metaverse meant for us, its fantasy and reality, and the development in the current hype. Experience of exploration and creation of the metaverse is shared and lesson learnt, and takeaway is discussed.