Events

Physics Master of Science Thesis Defense - Emma Klinkhamer

Physics Master of Science Thesis Defense by Emma Klinkhamer Date: Thursday, July 29, 2021 Time: 9:00 AM Topic: Computational Methods in Electromagnetic Applications Zoom Conference Link: https://us05web.zoom.us/j/83126756712?pwd=TUtKNTRkRDc5QzZVN04xdW41czczdz09 Meeting ID: 831 2675 6712 Passcode: st7Nxr Abstract: Computational methods and algorithms are quickly becoming a necessity in science and engineering fields. These modeling techniques not only take the computational onus from the human brain, but can also provide visualizations for the problem at hand. This research delves into the facets of these computing processes, specifically at the intersection of electrostatic applications and iterative computational modeling. By first laying the groundwork for governing electrostatic equations, a general overview of surface charge distribution is discussed, and the need for accurate modeling techniques in this field is reviewed. Afterwards, some common algorithm types are analyzed, including finite element analysis and basic iterative computational structures. The heart of the thesis is devoted to merging a well-established surface charge distribution code with a Python based meshing algorithm to create a novel code meant for determining surface charge distribution and electric field in a realistic wire-like domain. Prior to going through this analysis, the Ruth Chabay and Bruce Sherwood surface charge distribution code is examined. Similarly, the Python based meshing package, called PyDistMesh, is explained. Finally, with these two software pillars thoroughly understood, the novelty and effectiveness of the combined code is assessed. ADVISOR(S): Dr. Jianyi Wang, Department of Physics (jwang@umassd.edu 508.999.9136 COMMITTEE MEMBERS: Dr. J.P. Hsu, Department of Physics Rob Slimm, Electrical Engineering Manager - Sensata Technologies

ECE Master of Science Thesis Defense and Research Component of PhD Qualifier Exam by: David Campos Anchieta

Topic: Improving The Robustness of The Dominant Mode Rejection Beamforming with Median Filtering Location: Charlton College of Business Conference Room, CCB-115 Abstract: Abraham's and Owsley's dominant mode rejection (DMR) beamformer modifies the Capon's minimum variance distortionless response (MVDR) to operate with low-rank sample covariance matrices (SCM). The DMR estimates the ensemble covariance matrix (ECM) from a low-rank SCM by replacing the eigenvalues of the noise subspace with an estimated noise power based on the sample mean of those same eigenvalues. This estimated noise power is negatively biased when the dominant subspace dimension is overestimated, which is common in real world implementations of the DMR. The proposed median DMR estimates the noise power from the median of the SCM eigenvalues, based on the Marchenko-Pastur probability distribution. The median estimator showed to be more robust to overestimation of the dominant subspace dimension, exhibiting a lower mean squared error than the mean estimator. Simulations show that the median DMR improves the white noise gain (WNG) when compared to the standard DMR in snapshot deficient scenarios with overestimated interferer subspace dimension. Higher WNG also implies increased robustness to array perturbations. This work compares the median DMR to standard DMR in simulations with perturbed array element phase responses in a scenario with two interferers and background white noise. The median DMR preserved deeper notches than standard DMR in this scenario, increasing the output signal-to-noise ratio by roughly 1.1 dB. Note: All ECE Graduate Students are ENCOURAGED to attend. All interested parties are invited to attend. Open to the public. Advisor: Dr. John R. Buck Committee Members: Dr. Dayalan P. Kasilingam and Dr. Paul J. Gendron, Department of Electrical & Computer Engineering, UMASS Dartmouth; Dr. Honglei Chen, Principal Engineer, The MathWorks, Inc. *For further information, please contact Dr. John R. Buck via email at jbuck@umassd.edu.

Orientation

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First Day of Classes

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Labor Day: No Classes

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Monday Class Schedule / Last Day for Add-Drop

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Marc St. Pierre: Black & White - Star Store Campus

Marc St. Pierre: Black & White Location: University Art Gallery, Star Store Campus, Downtown New Bedford, MA Open through September 9, 2021 Reception: AHA! Night, Thursday, August 12, 6-8 pm Gallery hours: Mon-Fri 9 am - 6 pm and until 9 pm during AHA! Nights (second Thursday of every month) The University Art Gallery in New Bedford is proud to present Black & White, an exhibition by a beloved UMass Dartmouth professor, the late Marc St. Pierre (June 23, 1952 - December 2, 2019), featuring a selection of mixed media drawings and collage with encaustic, as well as black and white photography. Drawings created between 2008 and 2012, layered geometric elements, and abstract forms create a rich and poignant experience filled with wonder and exploration. They took inspiration from the 'man-made', architectural plans, diagrams, and maps of early explorers. In his artist statement from 2012, Marc said,As the drawing process evolves, organic shapes and gestural lines are introduced over the groundwork in transparent overlays. This provides a counterpoint to the precision associated with the geometry and acts as a multiple exposure in photography. This pictorial space becomes a dialog of random marks that combines the constructed with the unsystematic. My drawings intend to move the eye within an abstract and shallow picture plane in a gradual release of time. The illusion of a 'deep space' in Marc's work, invites visitors into a complex, hazy, and multi-dimensional world of collage and encaustics that are presented in smaller formats in the exhibition. Describing his process in 2017, Marc wrote, "First, I use a variety of printmaking processes as a departure for recording marks, surfaces, and layers. This becomes a collage groundwork that allows me to invent the abstract equivalent of land patterns such as the meeting point of landmasses and water, for example. Secondly, additional layers of tracings from actual maps and topographic patterns are introduced. These drawings become a physical overlay suspended in translucent wax." Curiosity and the connection between the creative and scientific, as well as an equally strong interest in observing the tangible are also very much a part of Marc's pinhole camera work shown at Crapo Gallery. After his retirement in 2017, Marc was often seen counting the time of his exposures while photographing various New Bedford locations. According to Gallery Director, Viera Levitt, "Marc would talk about taking his pinhole photographs, leaving for these expeditions from the Star Store Campus with a repurposed box readied with a small hole for capturing images directly on the photo paper. He enjoyed telling stories to his impromptu audiences including the building guard, about the random passers-by, observing his 'mysterious box' on the ground, ready to 'shoot'! It was indeed magic to see the one-of-a-kind monotypes he was able to capture with such simple, but skilled technique and his great patience for experimentation." The exhibition is open through September 9 during the gallery hours Mon-Fri 9 am-6 pm and until 9 pm during AHA! Nights (the second Thursday of every month). The special reception is planned for Thursday, AHA! Night, August 12, from 6 to 8 pm. More information about the exhibition, please visit www.umassd.edu/cvpa/universityartgallery For information about the Marc St. Pierre Memorial Scholarship, please visit giving.umassd.edu/stpierre. Please Note: Masks are encouraged, but not required for fully vaccinated individuals. Please maintain a 6-foot distance from others. Large bags, food, and beverages are not allowed in the gallery. If you or a member of your party has or has had cold or flu-like symptoms, do not visit the gallery until after everyone is well and has completed a medically recommended quarantine period. facebook.com/UMassDartmouthGalleries instagram.com/UMassDartmouthGalleries

Columbus Day: No Classes

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Thursday Class Schedule

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Veterans Day: No Classes

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Thanksgiving Recess

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Last Day of Classes

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