Wave Multiple Scattering in Random Rough Surface and Volume Scattering with Applications to Radar and Radiometric Earth Remote Sensing

Room: 3316, Bldg: EECS, 130 Beal Ave, Ann Arbor, Michigan, United States, 48109-2122

[] Electromagnetic scattering from natural surfaces and layered media plays a central role in microwave remote sensing of the Earth. Accurate interpretation of radar observations requires physically consistent modeling of rough-surface scattering from land and ocean and volumetric interactions within snowpacks. However, commonly used analytical and empirical models are often limited by simplifying assumptions that neglect multiple scattering and depolarization mechanisms, leading to discrepancies between modeled and observed radar signatures. This lecture investigates electromagnetic wave scattering from complex geophysical surfaces using a fast multilevel sparse-matrix canonical grid (FML-SMCG) method. FML-SMCG is developed to enable large-scale simulations of three-dimensional rough surfaces with large root-mean-square heights and slopes. The study examines scattering from fractal soil and ocean surfaces under extreme winds at L-band (1.26GHz), and rough surfaces at C- (5.5GHz), X- (9.6GHz) and Ku- (17.2GHz) bands. Further, volume scattering is studied within snowpacks using bi-continuous dense media radiative transfer (Bic-DMRT) to capture cross-polarized scattering from snow at C-, X- and Ku-bands. Building on these physical insights, a parameterized volume scattering model is developed for snow water equivalent retrieval using X- and Ku-band radar observations. The results provide improved understanding of depolarization mechanisms and support the development of more accurate remote sensing retrieval algorithms. Speaker(s): Firoz Borah, Room: 3316, Bldg: EECS, 130 Beal Ave, Ann Arbor, Michigan, United States, 48109-2122

Computational Electromagnetics from Maxwells Equations

Apex Test Labs, 815 N Opdyke Road, Auburn Hills, Michigan, United States, 48326

Pizza Sponsor: (https://www.cornucopiatechnicalsales.com/) Venue Sponsor: (https://www.apextestlabs.com/) Kristof P. von Czarnowski Speaker Bio: Kristof P. von Czarnowski is an RF and hardware engineer specializing in high-frequency and mixed-signal system design for automotive applications. At Lear Corporation since 2022, he leads transceiver design, implementation, and validation, while also contributing to low- and high-voltage hardware platforms with a focus on signal integrity, power integrity, and electromagnetic susceptibility and emissions. He serves as an electromagnetic compatibility (EMC) simulation subject matter expert, working to shift EMC from reactive post-test mitigation to proactive design integration. His work aims to embed EMC constraints directly into the development process through design guidelines, automated design rule checks, simulation workflows, and libraries - pushing for earlier issue detection, reducing validation risk, and improving first-pass success rates across schematic design, PCB layout, and compliance validation. Kristof holds undergraduate and graduate degrees in engineering from Oakland University, where he specialized in electromagnetics and wireless systems. His technical interests include practical EMI/EMC simulation workflows, SI/PI co-design, and model validation for RF and power distribution networks. His recent work explores AI-assisted engineering tools and machine learning approaches to automate component characterization and accelerate system-level EMC prediction - ad dressing the industry's missing-model bottleneck that prevents full system-level compliance prediction. Abstract Every electromagnetic compatibility problem begins with Maxwell's equations. Yet the path from fundamental physics to actionable EMC prediction remains opaque to many practicing engineers. This presentation aims to demystify this journey. We start at the foundation: how Maxwell's equations in differential and integral form lead to fundamentally different numerical solver families - volume-based methods (FEM, FDTD) versus surface-based methods (MoM, PEEC). The choice is not arbitrary; it is dictated by your problem's physics, materials, and electrical size. Through practical examples, we demonstrate solver selection for automotive EMC: when to use full-wave 3D versus quasi-static extraction, how to bridge the MCAD/ECAD domain gap, and why near-field antenna geometry matters. A detailed biconical antenna walkthrough demonstrates the complete workflow - from geometry definition exploiting axial and planar symmetries, through material assignment strategies (PEC versus realistic copper), radiation boundary setup for CISPR 25 test distances, port excitation, and convergence. But an antenna model alone does not predict EMI. The critical step is integration: combining the biconical antenna with a device harness in a unified simulation domain to capture mutual coupling, then extracting S-parameters for the complete antenna-harness-LISN system. We demonstrate the EM-to-SPICE handoff - Touchstone curve-fitting with passivity and causality enforcement, integration with nonlinear sources, and time-domain-to-frequency-domain conversion for emission prediction. The practical bottleneck is not Maxwell's equations - the physics is solid. The challenge is missing component models when modeling your DUT (e.g., PCB with SMD components). Vendor libraries are incomplete or physically inconsistent (non-passive, non-causal), and measuring every passive on a real BOM is not scalable. We conclude with a physics-informed machine learning approach that synthesizes broadband capacitor models from part descriptions alone, achieving accuracy sufficient for design comparison without waiting for vendor data. Simulation does not replace measurement. But it enables the critical capability every EMC engineer needs: the ability to rank design alternatives before building hardware. Layout variant A versus B. Filter topology trade-offs. Shielding effectiveness. You don't need absolute dBμV accuracy to pick the better design - you need the ranking to be correct. And when combined with analytical design rule checking and validated component models, computational electromagnetics delivers that predictive capability early in the design cycle, where changes are inexpensive and design freedom is highest. Agenda: 5:30 Pizza and networking 6:00 Presentation 7:30 End Apex Test Labs, 815 N Opdyke Road, Auburn Hills, Michigan, United States, 48326

Complexity of the Internet—An AI Observation Science Perspective

Room: 32-G449 (Kiva), Bldg: MIT building 32, 32 Vassar St, Cambridge, Massachusetts, United States, Virtual: https://events.vtools.ieee.org/m/533802

Boston Chapter of the IEEE Computer Society and GBC/ACM 7:00 PM, Thursday, 23 April 2026 MIT Room 32-G449 (Kiva) and online via Zoom Complexity of the Internet—An AI Observation Science Perspective Jeremy Kepner, MIT Please register in advance for this seminar even if you plan to attend in person at https://acm-org.zoom.us/webinar/register/6717750000324/WN_Z5KGSMQBSg2dzjM7s_X0mw After registering, you will receive a confirmation email containing information about joining the webinar.Indicate on the registration form if you plan to attend in person. This will help us determine whether the room is close to reaching capacity. We plan to serve light refreshments (probably pizza) before the talk starting at around 6:30 pm. Letting us know you will come in person will help us determine how much pizza to order. We may make some auxiliary material such as slides and access to the recording available after the seminar to people who have registered. Abstract: What does “normal” look like in a system that grows, adapts, and scales at extraordinary speed? How do its underlying patterns shift as the network expands from its early days to a billion-fold increase in scale? In this seminar, Dr. Kepner will explore how advances in high-performance, privacy-preserving AI graph analysis tools open new windows into the Internet’s behavior. His work sheds light on emergence, structure, and stability within this constantly changing global system. Dr. Kepner will explain the deep connections between graphs and matrices and more general mathematical concepts of semirings and associative (token) arrays that are the foundations of modern large language model (LLM) agentic AI systems. These mathematical concepts form the basis of the high performance GraphBLAS sparse matrix standard and the D4M (Dynamic Distributed Dimensional Model) associative array library that can analyze the largest networks in the world while preserving privacy. Bio: Dr. Jeremy Kepner is an MIT Lincoln Laboratory Fellow. He founded the Lincoln Laboratory Supercomputing Center and pioneered the establishment of the Massachusetts Green High Performance Computing Center. He has developed novel big data and parallel computing software used by thousands of scientists and engineers worldwide. He has led several embedded computing efforts, which earned him a 2011 R&D 100 Award. Kepner has chaired the SIAM Data Mining conference, the IEEE Big Data conference, and the IEEE High Performance Extreme Computing conference. Kepner is the author of two bestselling books, Parallel MATLAB for Multicore and Multinode Computers, and Graph Algorithms in the Language of Linear Algebra. His peer-reviewed publications include works on abstract algebra, astronomy, astrophysics, cloud computing, cybersecurity, data mining, databases, graph algorithms, health sciences, plasma physics, signal processing, and 3D visualization. In 2014, he received Lincoln Laboratory's Technical Excellence Award. You can learn more about his work here: https://www.mit.edu/~kepner/ Kepner holds a BA degree in astrophysics from Pomona College and a PhD degree in astrophysics from Princeton University. He is a fellow of the Society of Industrial Applied Mathematics (SIAM) and is a faculty advisor to the MIT SIAM student group. Directions to 32-G449 - MIT Stata Center, 32 Vassar Street, Cambridge, MA: Please use the main entrance to the Stata Center at 32 Vassar Street (the entrance closest to Main street) as those doors will be unlocked. Upon entering, proceed to the elevators which will be on the right after passing a large set of stairs and a MITAC kiosk. Take the elevator to the 4th floor and turn right, following the hall to an open area; 32-G449 will be on the left. (https://whereis.mit.edu/?go=32) This joint meeting of the Boston Chapter of the IEEE Computer Society and GBC/ACM will be hybrid (in person and online). Up-to-date information about this and other talks is available online at https://ewh.ieee.org/r1/boston/computer/. You can sign up to receive updated status information about this talk and informational emails about future talks at https://mailman.mit.edu/mailman/listinfo/ieee-cs, our self-administered mailing list. Co-sponsored by: gbc/acm Speaker(s): Jeremy Kepner, Room: 32-G449 (Kiva), Bldg: MIT building 32, 32 Vassar St, Cambridge, Massachusetts, United States, Virtual: https://events.vtools.ieee.org/m/533802