BEGIN:VCALENDAR VERSION:2.0 X-WR-CALNAME:EventsCalendar PRODID:-//hacksw/handcal//NONSGML v1.0//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:America/New_York LAST-MODIFIED:20240422T053451Z TZURL:https://www.tzurl.org/zoneinfo-outlook/America/New_York X-LIC-LOCATION:America/New_York BEGIN:DAYLIGHT TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 DTSTART:19700308T020000 RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU END:DAYLIGHT BEGIN:STANDARD TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 DTSTART:19701101T020000 RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU END:STANDARD END:VTIMEZONE BEGIN:VEVENT CATEGORIES:Uncategorized DESCRIPTION:Abstract:In this talk, I will present Quadrature by Two Expansi ons (QB2X) for the evaluation of Helmholtz layer potentials, as well as re cent progress in developing Green’s function-based numerical methods for Maxwell’s equations. One of the main numerical challenges with these in tegral equation methods is the accurate and efficient evaluation of layer potentials with singular or nearly-singular kernels, especially when the t arget point is close to or on the boundary of the domain. By utilizing the smoothness properties of layer potentials in the interior and exterior of the domain, along with special partial-wave or local expansions that auto matically satisfy the underlying partial differential equations, the Quadr ature by Expansion (QBX) scheme is introduced. In addition to local expans ions, the QB2X method employs plane-wave type expansions to achieve a repr esentation that is numerically accurate at all target points within the co mputational box. Compared to QBX, QB2X incorporates explicit nonlinearity from the boundary geometry into the plane-wave expansions and follows stan dard Fast Multipole Method (FMM) error analysis. Consequently, QB2X overco mes many of the challenges associated with QBX and is well-suited for comp lex geometries. If time permits, as a second topic, I will present the Met hod of Fundamental Solutions (MFS) with a periodization scheme for time-ha rmonic Maxwell’s equations in bi-periodic multilayered media. This metho d is robust at the Wood anomaly and can achieve spectral convergence close to machine precision. Work on extending this method to integral equations using a fast direct solver is currently ongoing.\nEvent page: https://www .umassd.edu/events/cms/11-6-26-cscdr-seminar-with-min-hyung-cho-umass-lowe ll.php\nEvent link: https://www.cscdr.umassd.edu/seminars X-ALT-DESC;FMTTYPE=text/html:

Abstr act:

In this talk\, I will prese nt Quadrature by Two Expansions (QB2X) for the evaluation of Helmholtz lay er potentials\, as well as recent progress in developing Green’s functio n-based numerical methods for Maxwell’s equations. One of the main numer ical challenges with these integral equation methods is the accurate and e fficient evaluation of layer potentials with singular or nearly-singular k ernels\, especially when the target point is close to or on the boundary o f the domain. By utilizing the smoothness properties of layer potentials i n the interior and exterior of the domain\, along with special partial-wav e or local expansions that automatically satisfy the underlying partial di fferential equations\, the Quadrature by Expansion (QBX) scheme is introdu ced. In addition to local expansions\, the QB2X method employs plane-wave type expansions to achieve a representation that is numerically accurate a t all target points within the computational box. Compared to QBX\, QB2X i ncorporates explicit nonlinearity from the boundary geometry into the plan e-wave expansions and follows standard Fast Multipole Method (FMM) error a nalysis. Consequently\, QB2X overcomes many of the challenges associated w ith QBX and is well-suited for complex geometries. If time permits\, as a second topic\, I will present the Method of Fundamental Solutions (MFS) wi th a periodization scheme for time-harmonic Maxwell’s equations in bi-pe riodic multilayered media. This method is robust at the Wood anomaly and c an achieve spectral convergence close to machine precision. Work on extend ing this method to integral equations using a fast direct solver is curren tly ongoing.

Event page: https:// www.umassd.edu/events/cms/11-6-26-cscdr-seminar-with-min-hyung-cho-umass-l owell.php
Event link: https://www.cscdr.umassd.edu/seminars

DTSTAMP:20261030T003918 DTSTART;TZID=America/New_York:20261104T130000 DTEND;TZID=America/New_York:20261104T140000 LOCATION: Textiles 105A SUMMARY;LANGUAGE=en-us:CSCDR seminar with Min Hyung Cho (UMass Lowell), "Ac curate Numerical Methods for Acoustic and Electromagnetic Scattering Probl ems” UID:23f70d45d17055bc115a14de17033568@www.umassd.edu END:VEVENT END:VCALENDAR