Posts

Understanding the Coefficient of a PDE in the context of Electrical Tissue Property Imaging

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In this blog, I discuss how the coefficient of the elliptic partial differential equation \(\sum_{i=1}^3 \partial_i \big( a_{ij}\,\partial_j u \big) = 0\) in a body arises in the context of electrical tissue property imaging, where \(u\) denotes the electrical potential. In brief, bioimpedance is directly linked to this coefficient, and several companies , such as  InBody  and  Sciospec , are actively developing bioimpedance-based devices. This blog is based on the book *Electromagnetic Tissue Properties MRI* (Imperial College Press) written by Jin Keun Seo, Eung Je Woo, Ulrich Katscher, and Yi Wang.  The mathematical model for electrical tissue property imaging is derived from an appropriate reduction of Maxwell’s equations. In the time-harmonic regime, the electric field \( \mathbf{E} \), current density \( \mathbf{J} \), magnetic field \( \mathbf{H} \), and magnetic flux density \( \mathbf{B} \) satisfy the following relations: Gauss's law: \( \nab...

Practical Vector Calculus for the AI Era

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1. Vectors Vectors  are mathematical entities characterized by both magnitude and direction. They are essential for describing physical quantities such as blood flow velocity, forces acting on joints, and features in image analysis for deep learning. A vector in three-dimensional space is written as: \[ \mathbf{v} = v_x \hat{i} + v_y \hat{j} + v_z \hat{k}, \] where \(\hat{i} = (1,0,0)\), \(\hat{j} = (0,1,0)\), and \(\hat{k} = (0,0,1)\) are the unit vectors along the \(x\)-, \(y\)-, and \(z\)-axes, respectively. The components \(v_x\), \(v_y\), and \(v_z\) represent the magnitude of the vector in the \(x\)-, \(y\)-, and \(z\)-directions.  Vectors can describe the speed and direction of  blood flow  in vessels, facilitating the analysis of hemodynamics. They are also used to model  forces  acting on prosthetic joints or tissues, aiding in the study of biomechanics and prosthetic design. A vector in \(n\)-dimensional space is written as: \[ \mathbf{x} = (x_1, ...

Selling Dreams in the Age of Speculative Technology

In today’s financial markets, a troubling asymmetry has emerged between those who sell technological dreams and those who buy them. Founders, CEOs, and early investors often understand how distant true commercialization remains, while many young retail investors—driven by optimism and headlines—see only the promise, not the timeline. This imbalance creates a structural divide: the informed side monetizes expectations, while the uninformed side absorbs the losses. Quantum computing offers a striking example. The 2025 Nobel Prize in Physics was awarded to John Clarke, Michel H. Devoret, and John M. Martinis “for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit.” Their work revealed that quantum effects—once confined to the microscopic world—can emerge in circuits large enough to see, laying the foundation for today’s superconducting qubits. Quantum systems promise radically new ways of computation through superposition, entangleme...

AI-Supervised Home Palliative Care: A Comfort-First and Cost-Effective Alternative to Hospital-Based End-of-Life Care

This blog is based on my personal experience caring for my palliative mother, who at that time was expected to live less than two months. I am not a doctor. It reflects on how end-of-life care often brings unnecessary discomfort to patients, even when death is near. Palliative care should focus on comfort, dignity, and relief from symptoms—not on prolonging life through medical intervention. Yet, hospital routines designed for safety can easily go too far. Nurses and doctors are required to follow strict protocols that call for frequent vital checks, blood tests, and continuous monitoring. Much of this comes from fear of legal responsibility rather than medical need. As a result, even patients in their final hours are often subjected to repeated procedures that offer no benefit but cause distress. Many remain connected to machines until their last moments. Families watch their loved ones in pain, realizing that such interventions contradict the essence of palliative care. The system ne...

Beyond the Comfort Zone: Rethinking Higher Education in the Age of AI

This piece offers a personal reflection on the relevance of today’s university system in a world where AI increasingly shapes how knowledge is delivered and how research is conducted. Rather than revisiting familiar debates, the focus here is on less-discussed inefficiencies that have gradually taken root within higher education. A helpful parallel can be found in the world of Go (baduk). Before AlphaGo, Go education relied on apprenticeship: students trained under veteran instructors who refined their technique and supported them through setbacks. This changed dramatically after AlphaGo’s 2016 victory over Lee Sedol. AI tools such as KataGo and Leela Zero now guide much of young players’ learning, offering strategies that challenge and often surpass long-held conventions. One Korean prodigy reportedly trained almost exclusively with AI for a year, developing an unconventional style that quickly carried him to the top. Human mentors still matter, but their role has shifted toward inter...