Events

ECE Doctor of Philosophy Dissertation Defense By: Bentolhoda Jafary

Topic: Reliability and Maintenance Modeling of Systems Subject to Positive and Negatively Correlated Component Failure Location: Lester W. Cory Conference Room, Science & Engineering Building (SENG), Room 213A ABSTRACT: Modern society increasingly depends on engineered systems in diverse fields such as defense, communication, and healthcare. Both the reliability and maintainability of these systems is therefore paramount. Past research had developed models to identify optimal periodic maintenance policies such as those that minimize cost or maximize availability. However, these maintenance policies may be suboptimal when the components of a system are subject to correlated or dependent failure. Moreover, the vast majority of past research on correlated and dependent failure is focused on positive correlation and dependence, yet negative correlation and dependence are also important to the design of resilient systems. To address these limitations, this dissertation makes several modeling and methodological contributions in the context of a variety of system and software reliability and maintenance contexts, including binary state systems, consecutive k-out-of-n: failed systems composed of multi-state components, and a software computation subject to checkpointing operations. Primary contribution include: (i) models and methods to quantify the impact of correlated failures on maintenance models in order to identify optimal maintenance intervals despite correlated failures and (ii) efficient methods to obtain algebraic expressions with explicit correlation parameters as well as exact numerical methods for the reliability of systems composed of non-identical components and arbitrary combinations of nonidentical positive and negative correlations between the failures of the components. NOTE: All ECE Graduate Students are ENCOURAGED to attend. All interested parties are invited to attend. Open to the public. Advisor: Dr. Lance Fiondella Committee Members: Dr. Hong Liu and Dr. Liudong Xing, Department of Electrical & Computer Engineering, UMass Dartmouth; Dr. Donghui Yan, Department of Mathematics, UMass Dartmouth; Dr. Mark White, NASA Jet Propulsion Laboratory *For further information, please contact Dr. Lance Fiondella at 508.999.8596, or via email at lfiondella@umassd.edu.

SBA Meeting

Greetings UMass Law: Welcome (or welcome back!) to another exciting year. The Student Bar Association would like to invite all law students to attend its first meeting this upcoming Wednesday afternoon. The meeting is this Wednesday, August 21, 2019 from 12:00 p.m. - 1:00 p.m. in room 116. We strongly encourage the attendance of the student organization presidents so that we have all updated contact info and can give out information regarding the monetary request process. Best, SBA E-Board

ECE Master of Science Thesis Defense By: Nicholas J. Vincelette

Topic: Doppler Properties of Acoustic Scattering from Ocean-Like Surfaces Location: Lester W. Cory Conference Room, Science & Engineering Building (SENG), Room 213A Abstract: In SONAR systems and underwater acoustic communications, acoustic signals that propagate in the ocean are scattered in different directions, when they encounter the air-water interface. Since the ocean surface is a dynamic boundary, the scattering process is time dependent and will result in the signal spectrum experiencing Doppler broadening. The focus of this research is on the scattering of longitudinal waves from ocean-like surfaces. Since the air-water interface is a soft boundary, the scattering of transverse waves, also known as shear waves, may be ignored. For the purpose of clarity, this study will focus on one-dimensional ocean-like surfaces. The study will investigate the effect of long surfaces waves (>> acoustic wavelength) on acoustic scattering. The study will also investigate the impact of acoustic wave frequency on the scattering process. By modeling the scattering from dynamic ocean-like surfaces that have varying harmonics and time-dependent phase, one is able to investigate the Doppler properties of the scattered signal, which is critical in many sonar and acoustic communication applications. Coherence times of the scattered signals, which is used as a measure of Doppler broadening, are estimated for different ocean surface conditions. The project’s ultimate goal is to incorporate these factors in a rigorous study of the Doppler spectral properties of the scattered waves. NOTE: All ECE Graduate Students are ENCOURAGED to attend. All interested parties are invited to attend. Open to the public. Advisor: Dr. Dayalan P. Kasilingam Committee Members: Dr. David A. Brown and Dr. Paul J. Gendron, Department of Electrical & Computer Engineering, UMASS Dartmouth and Dr. Raymond N. Laoulache, College of Engineering, UMASS Dartmouth *For further information, please contact Dr. Dayalan P. Kasilingam at 508.999.8534, or via email at dkasilingam@umassd.edu.

Litigation with the U.S. D.O.J. Tax Division (PILF)

Join UMass Law for a Public Interest Law Fellowship event, "Litigation with the U.S. D.O.J. Tax Division", on August 21st at 5:30pm. For more information, contact Dean Quinn at jquinn3@umassd.edu. This event is PILF APPROVED.

The Life of a Federal Public Defender with Jawara Griffin '09 (PILF)

Join UMass Law and Legal Career Services on Thursday, August 22nd at noon as we welcome Jawara Griffin '09 who will speak in the Moot Court Room and share his inspiring story and decade long career in the public sector! For almost a year now Attorney Griffin has been living in Tennessee and working for the Federal Public Defender for the Western District of Tennessee. Prior to that he worked for the Maryland Office of the Public Defender, and before that he was with CPCS here in Massachusetts. After years of public speaking engagements about his life, he recently wrote and self-published his autobiography "Homeboy" (https://www.amazon.com/Homeboy-Jawara-Griffin/dp/1096328321). This event is PILF Approved. For more information, please contact Legal Career Services at 508-985-1165.

Briefing for Part-Time PILF Students

Part-Time PILF students are encouraged to attend this briefing with Dean Quinn, Assistant Dean for Public Interest Law and External Relations. For more information, contact Dean Quinn at jquinn3@umassd.edu.

Pride at Work: Being Out at Work in the Past and Present

Providencetown Public Library, 356 Commercial St.

Last Day of Add/Drop

For more information, contact UMass Law at 508-985-1100.

ECE Master of Science Thesis Defense By: Matthew D. Tidwell

Topic: Designing Linear FM Active Sonar Waveforms for Continuous Line Source Transducers to Maximize The Fisher Information at a Desired Bearing Location: Lester W. Cory Conference Room, Science & Engineering Building (SENG), Room 213A ABSTRACT: Several authors previously found that echolocating animals aim their sonar beam to place the target of interest slightly off the main beam axis. Analysis found the animals' beam aiming strategy maximized the Fisher Information (FI) about the target bearing encoded in the frequency spectrum of the received echoes by the transmitter's frequency dependent beampatterns. This thesis reverses the focus from analysis to synthesis. We present design methods to maximize the FI of the bearing estimate at a desired angle using linear frequency modulated (LFM) waveforms transmitted by a continuous line source (CLS) transducer. If the bandwidth of the transmitted chirp is sufficiently small relative to the center frequency, the angle maximizing the bearing FI is solely determined by the center frequency. The center frequency is shown to place a null in the transducer's beampattern at the target's angular location or, equivalently, the target's angular location places a null in the received echo at the corresponding center frequency. This maximizes the waveform's relative variation resulting in favorable auto-correlation properties. Increasing bandwidth increases robustness to target bearing mismatch at the cost of decreased precision at the target's true angular location. NOTE: All ECE Graduate Students are ENCOURAGED to attend. All interested parties are invited to attend. Open to the public. Advsior: Dr. John R. Buck Committee Members: Dr. Dayalan P. Kasilingam, Department of Electrical & Computer Engineering, UMASS Dartmouth and Dr. Mary H. Johnson, Naval Undersea Warfare Center *For further information, please contact Dr. John R. Buck at 508.999.9237, or via email at jbuck@umassd.edu.

ABCs of Networking (PILF)

Join Dean Quinn as he discusses his top tips for networking on August 28th at 12pm on Moot Court Room. For more information, contact Dean Quinn at jquinn3@umassd.edu. *PILF APPROVED*

UMass Law Library Fair

Join the law librarians as we showcase all the fantastic resources the library has to offer! There will also be FOOD, GIVEAWAYS, and a big RAFFLE! Contact lawlib@umassd.edu for more information.

Student Bar Association (SBA) Org Fair

Get involved at UMass Law! Student organization representatives will be tabling from 12-6:30PM on August 28th. Come by, meet other students, and get involved. For more information, contact Dean Cahill at jcahill2@umassd.edu.