Northeastern University College of Engineering

Justin Crabb's PhD Proposal Review
2022-09-22 13:00 - 14:00 (America/New_York) | 432 ISEC, 360 Huntington Ave, Boston, MA, 02115, United States
“Multiphysics Simulation of Graphene Transistors for On-Chip Plasmonic THz Signal Generation and Modulation”
Abstract:
Terahertz communication is envisioned as a key technology not only for the next generation of macro-scale networks (e.g., 6G+), but also for transformative networking applications at the nanoscale (e.g., wireless nanosensor networks and wireless networks on chip). This proposal focuses on the development of a multiphysics simulation platform for a plasmonic THz nanogenerator with on-chip modulation. The in-house developed finite-element-method platform, which self-consistently solves the hydrodynamic and Maxwell’s equations, is utilized to provide extensive numerical results demonstrating the device’s functionality along with ultra-wide bandwidth and high modulation index capabilities.
First, a comprehensive theory of the Dyakonov-Shur (DS) plasma instability in current-biased graphene transistors is presented. Using the hydrodynamic approach, equations describing the DS instability in the two-dimensional electron fluid in graphene at arbitrary values of electron drift velocity are derived. These non-linear equations together with Maxwell’s equations are used for numerical analysis of the spatial and temporal evolution of the graphene electron system after the DS instability is triggered by random current fluctuations. Conditions necessary for the onset of the DS instability and the properties of the final stationary state of the graphene electron system are analyzed.
Next, a detailed numerical analysis of the DS plasma instability in the DC current-biased graphene transistor with the gate shifted with respect to the middle of the transistor conducting channel is presented. The geometric asymmetry is shown to be sufficient to trigger the DS instability in the two-dimensional electron gas in the transistor channel. Sustained plasma oscillations in the instability endpoint are demonstrated and the properties of these oscillations are analyzed for different positions of the gate and at different values of other physical and geometric FET parameters. The obtained results show the possibility of designing a tunable on-chip source of THz electromagnetic radiation based on the graphene transistor with a shifted gate.
Following, the on-chip THz nano-generator with amplitude and frequency modulation capabilities is presented. The proposed device uses and leverages the tunability of the Dyakonov-Shur instability for the growth and modulation of plasmonic oscillations in the two-dimensional electron gas channel of the graphene transistor.

Committee:
Prof. Josep Jornet (Advisor)
Prof. Tommaso Melodia
Prof. Matteo Rinaldi
Prof. Hossein Mosallaei

Deep Learning Guided Electrified Interfacial Chemical Processes
2022-09-21 12:00 - 13:00 (America/New_York) | 236 Richards, 360 Huntington Ave, Boston, MA, 02115, United States
ChE Seminar Series Presents:
Dr. Fanglin Che, Assistant Professor
Department of Chemical Engineering, University of Massachusetts Lowell
Abstract:
The usability and costly storage issues of renewable electricity from solar or wind energy become major challenges on a global scale due to the daily and seasonal variability of sunlight or wind and the geographic inequality of energy needs. A promising solution to address the above challenges lies in electrified modular chemical processes, which provide a sustainable approach to store the solar and wind electrical energy chemically. Theoretically determining and quantifying the roles of electrified interfacial structure and field-dipole interactions on controlling the activity and selectivity of chemical processes and then integrating these roles to establish deep collaborations between machine learning and electrified interfacial chemical processes is crucial for rationally designing these electrified modular systems for energy storage and sustainable chemical production. This talk will focus on two examples, one is organic-inorganic interface and its impact on electrocatalysis of carbon dioxide and the other one is field-dipole interaction effects on sustainable ammonia synthesis.
Biography:
Dr. Fanglin Che joined in Chemical Engineering department at UMass Lowell as an Assistant Professor in September, 2019. Dr. Che earned her Ph.D. in Chemical Engineering at Washington State University in December, 2016, under the advisement of Prof. Jean-Sabin McEwen. From 2017 to 2018, she worked on electrocatalysis with Prof. Edward Sargent at University of Toronto as a Postdoctoral Researcher. From 2018 to 2019, she worked on microwave heating as a Postdoctoral Researcher in the Department of Chemical and Biomolecular Engineering at University of Delaware in Prof. Dionisios G. Vlachos’s laboratory. The overarching goal of Dr. Che’s research at UMass Lowell is to advance the knowledge of electrified interfacial phenomena via building data-driven multi-scale and multi-physics computational models. A special focus is placed on electric field-induced chemistry, electrocatalysis, plasma catalysis, and microwave catalysis. Her group is currently funded by NSF, Navy, and Army.

COE Global Co-op Information Session!
2022-09-21 12:00 - 13:00 (America/New_York) | 440 Egan, 360 Huntington Ave, Boston, MA, 02115, United States
Join the College of Engineering Global Co-op team in learning about global co-op opportunities for Spring/ Summer I 2023! Topics discussed will include:

Search techniques and global positions in your field
Locations that students have co-oped in the past
What to consider when interested in a global co-op
Information on logistics, including health and safety
Tips and resources for self-developing global positions

Attendance to one of these information sessions is required if you plan to do a global co-op in Spring/ Summer I 2023. Please reach out to Sally Conant, Global Co-op Coordinator, s.conant@northeastern.edu or Kristina Kutsukos, Global Co-op Coordinator, k.kutsukos@northeastern.edu for additional information.
*Please note this workshop is catered towards graduate students in the College of Engineering and will be held in 440 Egan.

Grace Hopper Celebration 2022 - Orlando, FL
2022-09-21 08:00 - 2022-09-23 17:00 (America/New_York)
Join the Graduate Admissions team for an IN-PERSON recruiting event in Orlando, FL! The event will take place at Orange County Convention Center, Orlando, FL from September 20th to the 23rd. Registration and event details may be found at the website below. We look forward to seeing you there!

Enabling Engineering Kickoff Meeting
2022-09-19 17:00 - 18:00 (America/New_York) | 095 Cargill, 360 Huntington Ave, Boston, MA, 02115, United States
Enabling Engineering is a student organization that designs and builds devices to improve the lives of older adults, individuals with physical and cognitive disabilities, and the caregivers who assist them. Our projects aim to empower affected individuals by giving them greater independence, reducing medical burdens, and increasing social connectedness, at a minimal cost. Our projects are open to students of all ages. Whether you’re a fifth year who’s already heard about Enabling Engineering, or a first-year looking for an interesting club to join, we can use your help.
To hear about some of last year’s projects and learn how you can be a part of one this year, come to our kickoff meeting on Monday, September 19 at 5 pm in 095 Cargill.
As a member of Enabling Engineering, you will get design experience, use your skills to make a difference in a disabled person’s life, and connect with students and faculty from across the university.
We are welcoming students from every background, Including Volunteers, and Mentors who would like to be a part of us and help on some exciting range of projects.
Connect with us – enable@coe.neu.edu ​
Student form – https://lnkd.in/eQ7Y652e ​
Website – https://www.enablingengineering.org/

COE FacDev Friday: Identifying News Value in Your Work
2022-09-16 13:00 - 14:00 (America/New_York)

Galante Program Seminar Series
2022-09-15 18:30 - 20:00 (America/New_York) | 440 Egan, 360 Huntington Ave, Boston, MA, 02115, United States
Please join the Galante Engineering Business Program in welcoming seminar guest speaker Renee Thiesing (LinkedIn). Renee joins us from Louisville, Kentucky to share her inspiring career and personal journey along with important lessons regarding career, leadership, and management opportunities, personal and career development, opportunity identification, decision making, and more. Also included in her presentation is an impactful workshopping component.
Renee’s academic achievements include BS Industrial and Operations Management from University of Michigan ’98 and MS Industrial Engineering from Auburn University ’09. Her career success include roles such as Consultant and Technical Trainer at Lucent Technologies/Kenan Systems, Senior Applications Engineer, Vice President of Strategic Alliances, and Vice President of Products at Simio LLC, and Vice President of Marketing at Optilogic Inc.
Renee shares her personal bio as follows:
“I am a life long learner and passionate about the opportunities I currently see in the market around how technology is enabling and supporting digital transformation and improving efficiency across enterprises. It is an exciting time to be part of the digital revolution, seeing how digital twins and artificial intelligence are being democratized and accelerating growth. I have enjoyed my history of working in the computer software industry to strategically assist customers with utilizing technology for operational improvement and value for the bottom line. I have strong business development skills, technical aptitude and a passionate vision for how the fourth industrial revolution can be utilized to bring value to entire supply chains across all industries.”
The seminar event will take place from 6:30-8:00pm and business formal attire is required. To RSVP and join, please reach out to Galante Program Assistant Bradley Miller directly at b.miller@northeastern.edu, upon which you will receive a calendar invitation.

Northeastern University Virtual Open House
2022-09-14 08:00 - 11:00, 2022-09-13 08:00 - 10:00 (America/New_York)
Meet with the teams who’ll support you from application through graduation
During this informative and convenient two-day event, you can connect with faculty, staff, students, and admissions representatives on your schedule. Choose from live sessions and on-demand videos to get the information and answers you need to begin your graduate experience at Northeastern.
During these two days, you’ll be able to:

Connect with faculty and current students for a firsthand look into our community and your college of interest.
Meet other prospective master’s, PhD, and doctoral students from around the country and globe.
Chat with Northeastern staff during our elective sessions, including members from Student Financial Services, Library Services, Off-Campus Housing, Office of Diversity and Inclusion, enrollment counselors, and more.
Learn about our world-class co-op and internship program—ranked #1 by the Princeton Review.
Attend professional development sessions hosted by our Career Design teams—ranked #4 by the Princeton Review.
Customize your schedule so you can get the specific help and answers you need.

Fill out the form to secure your spot and join us on September 13-14.

COE Global Co-op Information Session!
2022-09-13 17:30 - 18:30 (America/New_York) | 440 Egan, 360 Huntington Ave, Boston, MA, 02115, United States
Join the College of Engineering Global Co-op team in learning about global co-op opportunities for Spring/ Summer I 2023! Topics discussed will include

Search techniques and global positions in your field
Locations that students have co-oped in the past
What to consider when interested in a global co-op
Information on logistics, including health and safety
Tips and resources for self-developing global positions

Attendance to one of these information sessions is required if you plan to do a global co-op in Spring/ Summer I 2023. Please reach out to Sally Conant, Global Co-op Coordinator, s.conant@northeastern.edu or Kristina Kutsukos, Global Co-op Coordinator, k.kutsukos@northeastern.edu for additional information.
*Please note this workshop is catered towards undergraduate students in the College of Engineering and will be held in 440 Egan.

QS Graduate Fair - Mexico City, Mexico
2022-09-10 10:30 - 13:00 (America/Mexico_City)
Join the Graduate Admissions team for an IN-PERSON event in Mexico City, Mexico! The event will take place at the Presidente Intercontinental Hotel from 10:30am-1:00pm CDT.
Registration and event details may be found at the link below. We look forward to seeing you there!

QS Graduate Fair - Bogota, Colombia
2022-09-08 18:30 - 21:00 (America/Bogota)
Join the Graduate Admissions team for an IN-PERSON recruiting event in Bogota, Colombia! The event will take place at the Casa Dann Carlton Hotel & Spa from 6:30-9:00pm COT.
Registration and event details may be found at the website below. We look forward to seeing you there!

QS Virtual Masters Event - Indonesia
2022-09-07 19:00 - 21:00 (Asia/Jakarta)
Northeastern University’s Graduate School of Engineering will be attending the QS Virtual Masters Event – Indonesia on Wednesday, September 7th from 7:00 PM – 9:00 PM WIB. Learn more about Northeastern’s Graduate Engineering programs!

Fall Fest 2022
2022-09-06 12:00 - 15:00 (America/New_York)
Following First Year Convocation, Fall Fest will take over all of campus as all of our student organizations and Student Affairs Offices table, give out SWAG, share food, and have a general blast! Check the Welcome Week schedule for more info and specific details, as well as a map of all our tables.

EducationUSA South Asia Graduate Fair
2022-09-03 18:00 - 21:00 (Asia/Kolkata)
Northeastern University’s Graduate School of Engineering will be attending the EducationUSA Virtual South Asia Graduate Fair on Saturday, September 3rd from 6:00 PM – 9:00 PM IST. Learn more about Northeastern’s Graduate Engineering programs!

QS Graduate Fair - Sao Paulo, Brazil
2022-09-03 15:00 - 17:30 (America/Sao_Paulo)
Join the Graduate Admissions team for an IN-PERSON recruiting event in Sao Paulo, Brazil! The event will take place at Hotel Transamerica from 3:00 PM to 5:30 PM BRT. Registration and event details may be found at the website below. We look forward to seeing you there!

QS Virtual Masters Event -Philippines
2022-08-31 18:00 - 21:30 (Asia/Manila)
An admissions representative, Emily DeRosa, Recruiting Specialist, will be present at the QS Virtual Masters Event – the Philippines taking place on Monday, August 31st from 6:00 PM – 9:00 PM PHT (6:00 AM – 9:30 AM EST). Learn more about the programs offered at Northeastern University’s Graduate School of Engineering.

Cornell 2022 Graduate and Professional School Fair
2022-08-29 08:00 - 17:00 (America/New_York)
Join the Graduate Admissions team for this VIRTUAL recruiting event! The event will take place from 1:00 PM to 4:00 PM EST. Registration and event details may be found at the website below. We look forward to seeing you there!

India Study Expo
2022-08-27 - 2022-08-28
Northeastern University will be visiting Hyderabad and Mumbai on August 27 and 28 to host in-person events. This is the first in-person event in 3 years. We look forward to meeting you then.

Library Webinar: Intro to R/RStudio (Virtual)
2022-08-26 12:00 - 13:30 (America/New_York)
Want to learn R and RStudio but don’t know where to start?
We’ll walk you through the steps of creating your first graph, beginning with opening RStudio for the first time and ending with tips on how to continue learning in order to pursue your own projects.
No prior experience with R, RStudio, or computer programming is required.
Installation of R and RStudio beforehand is required.

To install R, download and run this R installer for Windows or this R installer for macOS. If you run into any problems, please read further instructions on R’s website.
To install RStudio, download and run this RStudio installer for Windows or this RStudio installer for macOS. If you run into any problems, please read further instructions on RStudio’s website.

This workshop is presented by Kate Kryder, Data Analysis and Visualization Specialist at Northeastern University Library.
Please register at the library events calendar.
Please note: This session will not be recorded. If you’re interested in learning the material but don’t plan to attend, please don’t register for the session as seats are limited.

Library Bite-Sized Webinar: How do I (responsibly) edit Wikipedia?
2022-08-26 12:00 - 12:30 (America/New_York)
At some point in your education, you’ve probably heard that you should never use Wikipedia “because anyone can edit it.” But have you ever actually tried editing it yourself? This webinar will provide an introduction to Wikipedia’s editing tools and its dedicated community of editors, who voluntarily cultivate and maintain the free encyclopedia according to a set of five “pillars of Wikipedia.” Learn how and why you can—and should!—contribute to the world’s largest reference work.
This webinar is pre-recorded. To receive a captioned copy of the webinar to watch at your convenience, please register at the library events calendar and it will be sent to you at the time noted above.

Library Bite-Sized Webinar: How can I tidy my spreadsheet data?
2022-08-26 12:00 - 12:30 (America/New_York)
Everyone uses spreadsheets, but not everyone sets them up in the same way. This short video will share some good practices to keep spreadsheets tidy by using standard, predictable patterns to record data. These tips can help you avoid getting bogged down in the logistics of entering your data, and instead focus your time and energy on analyzing it.
This webinar is pre-recorded. To receive a captioned copy of the webinar to watch at your convenience, please register at the library events calendar and it will be sent to you at the time noted above (EST).

Library Bite-Sized Webinar: How can I navigate journal publication fees?
2022-08-26 12:00 - 12:30 (America/New_York)
What can you do when a journal in which you wish to publish charges a fee? In this session you will learn what article processing charges (APC) are and how to navigate APC, including: where you can look for funds to pay for APC, how the Northeastern University Library is helping to lower and eliminate APC, and tools for searching for open access journals which do not require APC.
This webinar is pre-recorded. To receive a captioned copy of the webinar to watch at your convenience, please register at the library events calendar and it will be sent to you at time noted above (EST).

Library Bite-Sized Webinar: How do I add a Creative Commons license to my work?
2022-08-25 15:00 - 15:30 (America/New_York)
You’ve probably heard about copyright, but are you familiar with Creative Commons (CC)? CC licenses allow you to retain the copyright to your work, even while granting advanced permissions to others who may want to use or build upon it.
In this session, you’ll learn the basics of the 6 Creative Commons licenses and how to actually apply a license to your work. We will also outline some considerations and questions to help you decide whether a CC license is right for you – and which one. Presented by Arts, Humanities, and Experiential Learning Librarian, Regina Pagani.
Registration is required. Please register at the library events calendar.
This live webinar will be held in EST. The webinar will be recorded, captioned and sent out to registrants. To receive a copy, please register at the library events calendar.

Tarik Kelestemur's PhD Dissertation Defense
2022-08-25 14:00 - 15:00 (America/New_York)
Location: ISEC 532
“Combining Classical and Learning-based Methods for Visual and Tactile Manipulation”
Abstract:
Robots that operate in dynamic and ever-changing environments need to make sense of their surroundings and act in them safely and efficiently. This requires the integration of multiple sensory modalities such as visual and tactile. Humans can naturally fuse different feedbacks from the environment or substitute them with one another to perform everyday tasks. For example, to use a computer mouse, we first locate the mouse using vision and then use touch feedback from our fingers to precisely localize the buttons. Ideally, we would like robots to have human-level perception and control of the environment to achieve various tasks. This dissertation address two significant problems toward this overarching goal.
The first problem we consider in this dissertation is figuring out how to use tactile information in conjunction with visual feedback. Robotic manipulators that interact with objects and environments are often equipped with visual sensors such as RGB and depth cameras. They estimate the state of their environment using these sensors and act upon the estimated state. While a large body of previous work has shown that we can achieve impressive results only with visual sensors, more precise and delicate tasks require touch information which gives direct feedback from the environment. To this end, we propose methods for efficiently combining the tactile and visual information to leverage the advantages of these modalities.
The second problem we investigate is how to build visual and tactile manipulation methods that can generalize over the different novel environments and objects. The rise of deep learning has enabled robots to solve challenging perception and control problems using visual and tactile observations while generalizing to novel objects and environments. However, a common issue among deep learning-based methods is that these methods usually work only within the distribution of the training data and do not perform well when they are presented with unseen examples. Furthermore, they cannot distinguish whether they are dealing with in or out-of-distribution data. We propose to address this issue by combining well-established and principled algorithmic priors with the generalization capabilities of deep learning.
In the first part of this dissertation, we investigate the problem of pose estimation of the robotic grippers with respect to the environment and objects. The proposed framework introduces a learnable Bayes filter that can estimate the position of a gripper in a single image of the environment. We learn the observation and motion models of the Bayes filter using modern neural network architectures and use recursive belief updates for tracking the position of the gripper over time. Later, the belief estimation is used as an input to policies where the aim is to solve manipulation tasks using tactile feedback. In the second part, we look at the problem of estimating shapes from partial observations. We propose a method called DeepGPIS that combines a powerful deep learning-based implicit shape representation with a non-parametric inference approach model for implicit surfaces (GPIS) which allows us to generate complete shapes of novel objects and estimate their predictive uncertainties.
Committee:
Prof. Taskin Padir (Advisor)
Prof. Robert Platt (Advisor)
Prof. David Rosen (Advisor)

2022 EducationUSA Virtual Fair
2022-08-24 18:00 - 21:00 (America/New_York)
Join the Graduate School of Engineering Admissions team at the 2022 EducationUSA Virtual Fair to learn about studying at the graduate level in the U.S. and our graduate Engineering programs!
Register for the event may be found through the website below.

Library Bite-Sized Webinar: How can I use citation tracking to find relevant research?
2022-08-24 15:00 - 15:30 (America/New_York)
This webinar is an introduction to ways of extending your research discovery using “cited by” and “highly cited” references found in Google Scholar, Web of Science, and Scholar OneSearch. Supercharge your results with forward and backward citation tools, analyze the data in your results, and learn the strengths and weaknesses of each one of these resources for tracking scholarly conversations through time. Presented by Head of Arts, Social Sciences, and Humanities at Northeastern University Library, Karen Merguerian.
Registration is required. Please register at the library events calendar.
This live webinar will be held in EST. The webinar will be recorded, captioned and sent out to registrants. To receive a copy, please register using this link.

Library Bite-Sized Webinar: How do I draw in PowerPoint?
2022-08-23 15:00 - 15:30 (America/New_York)
Need to annotate a figure or create a basic visual such as a Venn diagram? Have no time to learn a new, artsy drawing tool? We’ll share tips for using PowerPoint’s Shape tools to get the job done! This webinar will be presented by Data Analysis and Visualization Specialist, Kate Kryder.
Registration is required. Please register at the library events calendar.
This live webinar will be held in EST. The webinar will be recorded, captioned and sent out to registrants. To receive a copy, please register using this link.

Hamed Mohebbi Kalkhoran's PhD Dissertation Defense
2022-08-22 15:00 - 16:00 (America/New_York)
“Machine learning approaches for classification of myriad underwater acoustic events over continental-shelf scale regions with passive ocean acoustic waveguide remote sensing”
Abstract:
Underwater acoustic data contain a myriad of sound sources. Among underwater acoustic events, marine mammal vocalization classification is one of the most challenging problems due to their transient broadband calls, high variation in the calls of a specie, and high similarity between the calls of some species. Here, we developed machine learning approaches for classifying marine mammal vocalizations for real-time applications. We utilize acoustic data from a 160-element coherent hydrophone array and employ the passive ocean acoustic waveguide remote sensing technique to enable sensing and detections over instantaneous wide areas more than 100 km in diameter from the array. A variety of computational accelerating approaches, combining hardware and software, that make the methods desirable for real-time applications are also developed.
The humpback whale vocalizations can be divided into two classes, song and non-song calls. Here we use wavelet signal denoising and coherent array processing to enhance the signal-to-noise ratio. To build features vector for every time sequence of the beamformed signals, we employ Bag of Words approach to time-frequency features. Finally, we apply Support Vector Machine (SVM), Neural Networks, and Naive Bayes to classify the acoustic data and compare their performances. Best results are obtained using Mel Frequency Cepstrum Coefficient (MFCC) features and SVM which leads to 94% accuracy and 72.73% F1-score for humpback whale song versus non-song vocalization classification.
To classify a large variety of whale species vocalizations, we extracted time-frequency features from Power Spectrogram Density (PSD) of the beamformed signals. Then we used these features to train three classifiers, which are SVM, Neural Networks, and Random forest to classify six whale species: Fin, Sei, Blue, Minke, Humpback, and general Odontocetes. We also trained a set of Convolutional Neural Networks (CNN) to detect and classify each of these six whale vocalization categories directly using Per-Channel Energy Normalization (PCEN) spectrograms. Best results were obtained with Random forest classifier, which achieved 95% accuracy, and 85% F1 score. To detect transient sound sources, first we applied PCEN on the PSD of the beamformed signals. We applied thresholding on the PCEN data followed by morphological image opening to find potential sound sources and reduce noisy detections. Then we applied connected component analysis to obtain the final detected sounds for each bearing. To estimate the Direction of Arrival (DoA) of detected sounds, we applied non-maximum suppression (NMS), which is widely used in object detection applications in computer vision, on the detected sounds. We used mean power of each detected sound as the scores for NMS. To speed up the data processing, we investigated a variety of accelerating approaches, such as analyzing the effect of floating point precision, applying parallel processing, and implementing fast algorithms to run on GPU. During an experiment in the U.S. Northeast coast on board the US research vessel RV Endeavor in September 2021, we utilized the software and hardware advances developed here to record underwater acoustic data using Northeastern University in-house fabricated large aperture 160- element coherent hydrophone array with sampling frequency of 100 kHz per element.
Committee:
Prof. Purnima Ratilal (Advisor)
Prof. Themistoklis Sapsis
Prof. Devesh Tiwari

Mengshu Sun's PhD Dissertation Defense
2022-08-17 12:00 - 13:00 (America/New_York)
“Deep Learning Acceleration on Edge Devices with Algorithm/Hardware Co-Design”
Abstract:
As deep learning has succeeded in a broad range of applications in recent years, there is an increasing trend towards deploying deep neural networks (DNNs) on edge devices such as FPGAs and mobile phones. However, there exists a significant gap between the extraordinary accuracy of state-of-the-art DNNs and efficient implementations on edge devices, due to their limited resources for DNNs with high computation and memory intensity. With the target of simultaneously accelerating the inference and maintaining the accuracy of DNNs, efficient implementations are investigated of deep learning on low-power and resource-constrained devices, by presenting algorithm/hardware co-design frameworks that incorporate hardware-friendly DNN compression algorithms with hardware design optimizations.
First, the DNN compression algorithms are explored, leveraging quantization and weight pruning techniques. As for quantization, intra-layer mixed precision/scheme weight quantization is proposed to boost utilization of heterogeneous FPGA resources and therefore improving the FPGA throughput, by assigning multiple precisions and/or multiple schemes at the filter level within each layer and maintaining the same ratio of filters across all the layers for each type of quantization assignment. As for weight pruning, novel structured and fined-grained sparsity schemes are proposed and obtained with the reweighted regularization pruning algorithm, and then incorporated into acceleration frameworks on FPGAs to make the acceleration rate of sparse models approach the pruning rate of the number of operations.
Second, the hardware implementations are studied, proposing an automatic DNN acceleration framework to generate DNN accelerators to satisfy a target frame rate (FPS). Unlike previous approaches that start from model compression and then optimizing the FPS for hardware implementations, this automatic framework will provide an estimation of the FPS with the FPGA resource utilization analysis and performance analysis modules, and the bit-width is reduced until the target FPS is met and the mixing ratio for quantization precisions/schemes is automatically determined to guide the quantization process and the accelerator implementation on hardware. A resource utilization model is developed to overcome the difficulty in estimating the LUT consumption, and a novel computing engine for DNNs is designed with various optimization techniques in support of DNN compression to improve the computation parallelism and resource utilization efficiency.
Committee:
Prof. Xue Lin (Advisor)
Prof. Miriam Leeser
Prof. Xiaolin Xu
