Events

Date: Tuesday Oct 22, 2019 Time: 4-5pm Location: Textiles 101E Speaker: Dipshika Das Abstract: Zeolite, both natural and synthetic, has a great affinity for ammonium. This has drawn researchers attention for last few decades to utilize the full scope of this mineral to remove ammonium from aqueous solution. Removal of ammoniacal nitrogen from agricultural run-off and wastewater is particularly important as it causes eutrophication of lake. This results into the depletion of dissolved oxygen, presents in water and engenders a toxic environment for aquatic lives. In our study, we intend to explore the potential of alkaline hydrothermal treatment to improve the ammonium removal efficiency of a synthetic zeolite, Chabazite (ALZB-Na). The three main parameters of the hydrothermal treatment are temperature, time extent of treatment and concentration of the base. We have permuted these parameters in several way and prepared treated Chabazites respectively. The ammonium uptake of each such sample was studied further to establish the optimum condition for the alkaline hydrothermal treatment of Chabazite. For further information, please contact Dr. Tracie Ferreira at tferreira@umassd.edu or 508-910-6537.

Oct25

ECE Research Component of PhD Qualifier Exam By: Eric Kobina Aikins

Topic: Effect of Axial Pressure Treatment on Effective Coupling Coefficient of Piezoelectric PZT-5A for Electroacoustics Location: Lester W. Cory Conference Room, Science & Engineering Building (Group II), Room 213A Abstract: It was previously shown by R. Y. Nishi1 that effects of a high, static, one-dimensional stress on the properties of piezoelectric ceramics are important in the design of some types of underwater transducers. In a conventional mass-loaded resonator incorporating ceramic as the active element, the stress in the ceramic owing to the static water pressure in the direction of the polar axis of the ceramic, and can be larger than the water pressure when the ceramic cross-sectional area is smaller than the radiating face of the resonator. Changes in the high-field permittivity and loss due to hydrostatic pressure superimposed on a one-dimensional bias pressure were small, provided that the bias pressures were applied to the ceramics at least one week before the hydrostatic pressure. PZT-5A ceramic subjected to one-dimensional stress becomes anisotropic with substantial increase of the piezoelectric modulus d32 of its original value after exposure to static pressure in a direction perpendicular to the polar axis. Practical appreciation of this effect is not known from literature. Moreover, experimental work on the effect of hydrostatic pressure on the piezoelectric and high-field dielectric properties of two piezoceramic projector materials was presented by R. F. Brown2. Two materials, a modified barium titanate and modified lead zirconate titanate, were characterized by low dielectric losses at high fields. In the pressure range 0 to 10 000 psi and at non-resonant driving fields up to 3 kV/cm, the variations observed in the permittivity and piezoelectric strain constants with hydrostatic pressure were less than 7%, and no significant variations were found in the dielectric loss. Aging studies at 10,000 psi showed that the permittivity and dielectric loss for both materials reached constant values after a few minutes. This research is concerned with investigating the possibility of using axial pressure treated PZT-5A rings to improve the electromechanical parameters for electroacoustic applications. An xperimental technique of pressure treatment that allows dynamic measuring parameters of the ring in the process of exposure to the pressure is described. Results of the pressure treatment on parameters of the cylinders are presented. It is shown that the improvement in the PZT-5A coupling coefficient is about WHAT due to pressure treatment was stable over time. NOTE: All ECE Graduate Students are ENCOURAGED to attend. All interested parties are invited to attend. Open to the public. Advisor: Dr. David A. Brown Committee Members: Dr. Paul J. Gendron and Dr. Yifei Li, Department of Electrical & Computer Engineering, UMASS Dartmouth; Dr. Boris Aronov, Consulting Scientist, Artech Engineering Plus *For further information, please contact Dr. David Brown at 508.999.8479, or via email at dbrown@umassd.edu.

Oct25

ECE Seminar* Speaker: Dr. Xiaohui Liang, University of Massachusetts Boston (UMB)

Topic: Vivo: Enhancing the Security of Voice Control System Via Wireless Signal in IOT Environment Location: College of Engineering Conference Room, Textiles Building (TXT), Room 101E Abstract: With the prevalent of smart devices and home automations, voice command has become a popular User Interface (UI) channel in the IoT environment. Although Voice Control System (VCS) has the advantages of great convenience, it is extremely vulnerable to the spoofing attack (e.g., replay attack, hidden/inaudible command attack) due to its broadcast nature. In this study, we present WiVo, a device-free voice liveness detection system based on the prevalent wireless signals generated by IoT devices without any additional devices or sensors carried by the users. The basic motivation of WiVo is to distinguish the authentic voice command from a spoofed one via its corresponding mouth motions, which can be captured and recognized by wireless signals. To achieve this goal, WiVo builds a theoretical model to characterize the correlation between wireless signal dynamics and the user's voice syllables. WiVo extracts the unique features from both voice and wireless signals, and then calculates the consistency between these different types of signals in order to determine whether the voice command is generated by the authentic user of VCS or an adversary. To evaluate the effectiveness of WiVo, we build a testbed based on Samsung SmartThings framework and include WiVo as a new application, which is expected to significantly enhance the security of the existing VCS. We have evaluated WiVo with 6 participants and different voice commands. Experimental evaluation results demonstrate that WiVo achieves the overall 99% detection rate with 1% false accept rate and has a low latency. Biography: Xiaohui Liang is an Assistant Professor with the Department of Computer Science at University of Massachusetts, Boston (UMB). He was a Postdoctoral Researcher at Dartmouth College in 2014-2015. He received the PhD degree (awarded Outstanding Achievement in Graduate Studies) in Electrical and Computer Engineering, University of Waterloo, Canada, in 2013. He received the BSc (with the University Excellent Undergraduate Thesis Award) and MSc degree (with the Shanghai Excellent Master Thesis Award) in Computer Science from Shanghai Jiao Tong University, China, in 2006 and 2009, respectively. His research interests include networking security, wireless security, and security for mobile systems. He has published over 100 refereed journal and conference papers, and his H-Index is 44 as of September, 2019 according to Google Scholar. He is a member of IEEE and ACM. He received the Award for Excellence in Scalable Computing for Early Career Researchers from IEEE Technical Committee on Scalable Computing in 2017, the Best Land Transportation Paper Award from IEEE Vehicular Technology Society in 2017, the Internet of Things Technology Research Award from Google in 2016, the Best Paper Award in BodyNets 2010. He is the Single PI of an NIH R01 Project and the Lead PI of an NSF Project. Check http://faculty.umb.edu/xiaohui.liang/. The Seminars is open to the public free of charge. *For further information, please contact Dr. Honggang Wang at 508.999.8469, or by via email at hwang1@umassd.edu.

Nov11

Veterans Day Holiday - no classes

Veterans Day holiday, no classes today.

Nov15

Last day to Withdraw from a class

Today is the last day to withdraw from a class.

Nov27

Thanksgiving recess begins after last class

Thanksgiving recess begins today after last class or lab.

Dec2

Classes resume

Classes resume at 8am today.