Penn Engineering Events

GRASP On Robotics: “Advancing Innovations for Robotic Teams in Complex Environments”
2021-03-05 11:00 - 12:30 (America/New_York) | https://upenn.zoom.us/j/96715197752
Abstract: Complex real-world environments continue to present significant challenges for fielding robotic teams, which often face expansive spatial scales, difficult and dynamic terrain, degraded environmental conditions, and severe communication constraints. Breakthrough technologies call for integrated solutions across autonomy, perception, networking, mobility, and human teaming thrusts. As such, the DARPA OFFSET program and the DARPA Subterranean Challenge seek novel approaches and new insights for discovering and demonstrating these innovative technologies, to help close critical gaps for robotic operations in complex urban and underground environments.
Click here to join the Zoom Webinar

CIS Seminar: "Architecting Quantum Computing Systems in the Presence of Noise"
2021-03-04 15:00 - 16:00 | Zoom – Email CIS for link, cherylh@cis.upenn.edu
Quantum computers may solve some problems beyond the reach of classical digital computers. However, emerging quantum systems are typically noisy and difficult to control, leaving a significant gap between the exacting requirements of quantum applications and the realities of noisy devices. Bridging this gap is crucial – my work adapts conventional computer systems techniques to meet the critical theoretical and experimental constraints in quantum processors. I divide my talk into three parts: (i) introducing my recent work on systematic noise mitigation for superconducting transmon qubits [MICRO’20], which enhances the robustness of quantum processors through coordination of control instructions; (ii) demonstrating efficient and reliable quantum memory management [ISCA’20], which implements automated tools for allocation, reclamation and reuse of qubits in quantum programs, much like in garbage collection for classical programs; (iii) discussing on-going work on implementing quasi-fault-tolerant rotation gates in quantum error correction, which seeks to provide correctness guarantees for quantum applications by encoding quantum bits in a way that errors can be detected and corrected, analogous to classical error-correcting codes.

BE Dissertation Defense: "Uncovering Constraints on Organoid Morphologies" (Lauren Beck)
2021-03-04 11:00 - 13:00 | Zoom
The Department of Bioengineering at the University of Pennsylvania and Dr. Arjun Raj are pleased to announce the Doctoral Dissertation Defense of Lauren Beck.

Title: Uncovering Constraints on Organoid Morphologies

Date: March 4, 2021

Time: 11:00 AM

Zoom Link: https://upenn.zoom.us/j/94130810306

The public is welcome to attend via zoom.

ESE Seminar: "High-Level Synthesis of Dynamically Scheduled Circuits"
2021-03-04 11:00 - 12:00 | Zoom – Email ESE for Link jbatter@seas.upenn.edu
The slowdown in transistor scaling and the end of Moore’s law indicate a need to invest in new computing paradigms; specialized hardware devices, such as FPGAs and ASICs, are a promising solution as they can achieve high processing capabilities and energy efficiency. However, a major barrier to the global success of specialized computing is the difficulty of hardware design. High-level synthesis (HLS) tools generate digital hardware designs from high-level programming languages (e.g., C/C++) and promise to liberate designers from low-level hardware description details. Yet, HLS tools are still acceptable only for certain classes of applications and criticized for the difficulty of extracting the desired level of performance: generating good circuits still requires tedious code restructuring and hardware design expertise.
In this talk, I will present a new HLS methodology that produces dynamically scheduled, dataflow circuits out of C/C++ code; the resulting circuits achieve good performance out-of-the-box and realize behaviors that are beyond the capabilities of standard HLS tools. I will describe mathematical models to optimize the performance and area of the resulting circuits, as well as techniques to achieve characteristics that standard HLS cannot support, such as out-of-order memory accesses and speculative execution. These contributions redefine the HLS paradigm by introducing characteristics of modern superscalar processors to hardware designs; such behaviors are key for specialized computing to be successful in new contexts and broader application domains.

MSE Seminar: "Engineering nanoparticle-cell interactions: using a library-based approach to guide drug carrier design"
2021-03-04 10:45 - 11:45 | PA
Nanoparticles offer huge promise as drug delivery vehicles, though their translation to the clinic is hampered due to limited accumulation at target disease sites. To overcome this hurdle, we have employed colloidal layer-by-layer assembly to generate comprehensive nanoparticle libraries to study the role of chemical composition in nanoparticle targeting, trafficking, and uptake. In this seminar, use of these libraries to study interactions with ovarian cancer cells and develop a new class of multifunctional drug carriers will first be discussed. Expansion of our library-based approach via the use of high throughput, pooled screening and correlative genomics will be detailed in the second half. Key underlying principles from these studies will be highlighted for their potential to influence future nanocarrier design.

CIS Seminar: "The Measurement and Mismeasurement of Trustworthy ML"
2021-03-03 15:00 - 16:00 | Zoom – Email CIS for link, cherylh@cis.upenn.edu
Across healthcare, science, and engineering, we increasingly employ machine learning (ML) to automate decision-making that, in turn, affects our lives in profound ways. However, ML can fail, with significant and long-lasting consequences. Reliably measuring such failures is the first step towards building robust and trustworthy learning machines. Consider algorithmic fairness, where widely-deployed fairness metrics can exacerbate group disparities and result in discriminatory outcomes. Moreover, existing metrics are often incompatible. Hence, selecting fairness metrics is an open problem. Measurement is also crucial for robustness, particularly in federated learning with error-prone devices. Here, once again, models constructed using well-accepted robustness metrics can fail. Across ML applications, the dire consequences of mismeasurement are a recurring theme. This talk will outline emerging strategies for addressing the measurement gap in ML and how this impacts trustworthiness.

CBE Seminar: "Metal-Organic Frameworks as Tunable Platforms for Gas Storage, Chemical Separations and Catalysis"
2021-03-03 15:00 - 16:00 | Zoom – Email CBE for link
Abstract
Metal-organic frameworks (MOFs) are a versatile class of nanoporous materials synthesized in a “building-block” approach from inorganic nodes and organic linkers. By selecting appropriate building blocks, the structural and chemical properties of the resulting materials can be finely tuned, and this makes MOFs promising materials for applications such as gas storage, chemical separations, sensing, drug delivery, and catalysis. This talk will focus on efforts to design or screen MOFs for separating mixtures of small molecules, for gas storage, and for catalysis. Because of the predictability of MOF synthetic routes and the nearly infinite number of possible structures, molecular modeling is an attractive tool for screening new MOFs before they are synthesized. Modeling can also provide insight into the molecular-level details that lead to observed macroscopic properties. This talk will illustrate how a combined modeling and experimental approach can be used to discover, develop, and ultimately design new MOFs for desired separation, storage, and catalysis applications.

Spring 2021 GRASP SFI: “Safe and Data-efficient Learning for Robotics”
2021-03-03 11:00 - 12:30 | Zoom
Abstract: For successful integration of autonomous systems such as drones and self-driving cars in our day-to-day life, they must be able to quickly adapt to ever-changing environments, and actively reason about their safety and that of other users and autonomous systems around them. Even though control-theoretic approaches have been used for decades now for the control and safety analysis of autonomous systems, these approaches typically operate under the assumption of a known system dynamics model and the environment in which the system is operating. To overcome these challenges, machine learning approaches have been explored to operate autonomous systems intelligently and reliably in unpredictable environments based on prior data. However, learning techniques widely used today are extremely data inefficient, making it challenging to apply them to real-world physical systems. Moreover, they lack the necessary mathematical framework to provide guarantees on correctness, causing safety concerns as data-driven physical systems are integrated in our society.
In this talk, we will present a toolbox of methods combining robust optimal control with data-driven techniques inspired by machine learning, to enable performance improvement while maintaining safety. In particular, we design modular architectures that combine system dynamics models with modern learning-based perception approaches to solve challenging perception and control problems in ​a priori unknown environments in a data-efficient fashion. These approaches are demonstrated on a variety of ground robots navigating in unknown buildings around humans based only on onboard visual sensors. Next, we discuss how we can use optimal control methods not only for data-efficient learning, but also to monitor and recognize the learning system’s failures, and to provide online corrective safe actions when necessary. This allows us to provide safety assurances for learning-enabled systems in unknown and human-centric environments, which has remained a challenge to date.
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CIS Seminar: " Exterminating bugs in real systems"
2021-03-02 15:00 - 16:00 | Zoom – Email CIS for link, cherylh@cis.upenn.edu
Software is everywhere, and almost everywhere, software is broken. Some bugs just crash your printer; others hand an identity thief your bank account number; still others let nation-states spy on dissidents and persecute minorities.
This talk outlines my work preventing bugs using a blend of programming languages techniques and systems design. First, I’ll talk about securing massive, security-critical codebases without clean slate rewrites. This means rooting out hard-to-find bugs—as in Sys, which scales symbolic execution to find exploitable bugs in systems like the twenty-million line Chrome browser. It also means proving correctness of especially vulnerable pieces of code—as in VeRA, which automatically verifies part of the Firefox JavaScript engine. Finally, I’ll discuss work on stronger foundations for new systems—as in CirC, a recent project unifying compiler infrastructure for program verification, cryptographic proofs, optimization problems, and more.

MEAM Ph.D. Thesis Defense: "Reactive Planning with Legged Robots in Unknown Environments”
2021-03-02 14:00 - 15:00 | Zoom – Email MEAM for Link, peterlit@seas.upenn.edu
Unlike the problem of safe task and motion planning in a completely known environment, the setting where the obstacles in a robot’s workspace are not initially known and are incrementally revealed online has so far received little theoretical interest, with existing algorithms usually demanding constant deliberative replanning in the presence of unanticipated conditions. Moreover, even though recent advances show that legged platforms are becoming better at traversing rough terrains and environments, legged robots are still mostly used as locomotion research platforms, with applications restricted to domains where interaction with the environment is usually not needed and actively avoided.
In order to accomplish challenging tasks with such highly dynamic robots in unexplored environments, this research suggests with formal arguments and empirical demonstration the effectiveness of a hierarchical control structure, that we believe is the first provably correct deliberative/reactive planner to engage an unmodified general purpose mobile manipulator in physical rearrangements of its environment. To this end, we develop the mobile manipulation maneuvers to accomplish each task at hand, successfully anchor the useful kinematic unicycle template to control our legged platforms, and integrate perceptual feedback with low-level control to coordinate each robot’s movement.
At the same time, this research builds toward a useful abstraction for task planning in unknown environments, and provides an avenue for incorporating partial prior knowledge within a deterministic framework well suited to existing vector field planning methods, by exploiting recent developments in semantic SLAM and object pose and triangular mesh extraction using convolutional neural net architectures. Under specific sufficient conditions, formal results guarantee collision avoidance and convergence to designated (fixed or slowly moving) targets, for both a single robot and a robot gripping and manipulating objects, in previously unexplored workspaces cluttered with non-convex obstacles. We encourage the application of our methods by providing accompanying software with open-source implementations of our algorithms.

MSE Seminar: "Engineering topological phases in graphene moiré heterostructures"
2021-03-02 10:45 - 11:45 | PA
Taming topological electronic phases is a fundamental challenge and an important milestone on the way towards novel electronic devices and topological quantum computation. Recent advances in fabrication techniques have made van der Waals (vdW) heterostructures one of the most active platforms for the experimental investigation of topological electronic phases in 2D. Moiré superlattices, which arise from small rotational misalignment between layers in vdW structures, provide a powerful new way to control the electronic band structure. My talk will focus on using moiré superlattices in graphene heterostructures to realize quantum anomalous Hall (QAH) states that exhibit topological properties even in the absence of an external magnetic field. In contrast to magnetically doped topological insulators, the QAH states in these moiré systems are driven by intrinsic strong electronic interactions rather than by magnetic doping. Remarkably, the magnetization of this new family of QAH states arises predominantly from the orbital motion of the electrons rather than the electron spin. I will also discuss a novel effect originating from the curious magnetic properties of these “orbital magnets” that enables non-volatile electrical switching of the magnetic and topological orders.

MEAM Seminar: "Fusion for Robot Perception and Controls"
2021-03-02 10:30 - 12:00 | Zoom – Email MEAM for Link, peterlit@seas.upenn.edu
Machine learning has led to powerful advances in robotics: deep learning for visual perception from raw images and deep reinforcement learning (RL) for learning controls from trial and error. Yet, these black-box techniques can often require large amounts of data, have results difficult to interpret, and fail catastrophically when dealing with out-of-distribution data. In this talk, I will introduce the concept of “fusion” in robot perception and controls for robust, sample efficient, and generalizable robot learning. On the perception side, we fuse multiple sensor modalities and demonstrate generalization to new task instances and robustness to sensor failures that are out-of-distribution. On the controls side, we leverage fusion by combining known models with learned policies, making our policy learning substantially more sample efficient.

PSOC Webinar: "Polarity Signaling Ensures Epidermal Homeostasis By Coupling Cellular Mechanics and Genomic Integrity" (Sandra Iden)
2021-03-01 12:00 - 13:00 | PA
Physical Sciences in Oncology Center PSOC@Penn
Spring 2021 Webinar Series Mondays at 12:00 noon (EST)
For webinar links, please contact manu@seas.upenn.edu.

ODEI Spotlight: USABE Fireside Chat with Dr. CJ Taylor
2021-02-26 16:00 - 17:00 | PA
Fireside Chat with Dr. CJ Taylor
Date: Friday, February 26th
Time: 4:00 – 5:00 PM EST
Join USABE on Friday, February 26th at 4 PM for a conversation with Dr. CJ Taylor, Associate Dean for Diversity, Equity, and Inclusion at Penn Engineering, to discuss his experiences in STEM and engineering and his role as a professor in SEAS. Please register for the event and submit your questions for Dr. Taylor at tiny.cc/USABEfiresidechat.

PICS Colloquium: "Learning about learning by many-body systems"
2021-02-26 14:00 - 15:00 | PA
Abstract: Many-body systems from soap bubbles to suspensions to polymers learn the drives that push them far from equilibrium. This learning has been detected with thermodynamic properties, such as work absorption and strain. We progress beyond these macroscopic properties that were first defined for equilibrium contexts: We quantify statistical mechanical learning with representation learning, a machine-learning model in which information squeezes through a bottleneck. We identify a structural parallel between representation learning and far-from-equilibrium statistical mechanics. Applying this parallel, we measure four facets of many-body systems’ learning: classification ability, memory capacity, discrimination ability, and novelty detection. Numerical simulations of a classical spin glass illustrate our technique. This toolkit exposes self-organization that eludes detection by thermodynamic measures. Our toolkit more reliably and more precisely detects and quantifies learning by matter.

GRASP On Robotics: “Photoacoustic Vision for Surgical Robots”
2021-02-26 11:00 - 12:30 | Zoom
Abstract: The concept of “x-ray vision” is widely understood to be the ability to see through structures that are not transparent to the human eye. This concept would be a useful feature for surgeons and surgical robots, particularly when navigating complex anatomy. The Photoacoustic & Ultrasonic Systems Engineering (PULSE) Lab is developing imaging systems to offer this capability, but not with ionizing x-rays. Instead, we are utilizing a different wavelength on the electromagnetic spectrum, specifically the nm wavelengths required to induce the photoacoustic effect and enable photoacoustic imaging. To implement this vision, laser pulses delivered through optical fibers illuminate surgical regions of interest, causing an acoustic response that is detectable with ultrasound transducers. Beamforming is then implemented to create a photoacoustic image. In this talk, I will highlight novel light delivery systems, new spatial coherence beamforming theory, deep learning alternatives to beamforming, and robotic integration methods, each pioneered by the PULSE Lab to enable an exciting new frontier known as photoacoustic-guided surgery. This new paradigm has the potential to eliminate the occurrence of major complications (e.g., inaccurate targeting, excessive bleeding, paralysis, accidental patient death) during a wide range of delicate surgeries and procedures, including neurosurgery, cardiac catheter-based interventions, liver surgery, spinal fusion surgery, hysterectomies, biopsies, and teleoperative robotic surgeries.
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ODEI Event: Do You Have a Crew? The Importance of Friendship in Creating a Fulfilling Life
2021-02-25 19:00 - 21:00 | PA
Don’t isolate. Congregate! Join Penn Engineering’s Office of Diversity, Equity, and Inclusion to meet six dynamic men and learn about how their bonds of friendship and NSBE affiliation benefited them personally and professionally. Hear their story and engage in Q&A for the first hour (7PM-8PM). Then, meet someone new in breakout groups (8PM-8:30PM). An additional 30 minutes (8:30 PM-9PM) will be available for extended conversations. Do you have a crew? Join us to expand your circle!
Zoom Link: https://upenn.zoom.us/j/98242572639
Zoom ID: 982 4257 2639

CIS Seminar:"Probabilistic proofs: theory, hardware, and everything in between"
2021-02-25 15:00 - 16:00 | Zoom – Email CIS for link, cherylh@cis.upenn.edu
In the past decade, systems that use probabilistic proofs in real-world applications have seen explosive growth. These systems build upon some of the crown jewels of theoretical computer science—interactive proofs, probabilistically checkable proofs, and zero-knowledge proofs—to solve problems of trust and privacy in a wide range of settings.
This talk describes my work building systems that answer questions ranging from “how can we build trustworthy hardware that uses untrusted components?” to “how can we reduce the cost of verifying smart contract execution in blockchains?” Along the way, I will discuss the pervasive challenges of efficiency, expressiveness, and scalability in this research area; my approach to addressing these challenges; and future directions that promise to bring this exciting technology to bear on an even wider range of applications.

BE Seminar: "Dissecting Multicellular Therapeutic Responses Using a Large-scale Single-cell Profiling Platform" (Siyu Chen)
2021-02-25 15:00 - 16:00 | PA
This event will be held virtually via Zoom (check email or contact ksas@seas.upenn.edu).
Human diseases are fundamentally multicellular in nature with many different cell types contributing to disease progression and treatment response. However, how therapeutics impact each cell type in a heterogeneous population remains poorly understood because most studies are focused on isolated cell types or a handful of pathways. Now, single-cell transcriptional profiling methods allow us to collect a deep molecular portrait of the collective response of heterogeneous populations of cells to any perturbation. In my talk, I will present my research in harnessing the power of single-cell transcriptional profiling measurements to dissect therapeutic response in heterogeneous cell populations. In the first part, I will describe the probabilistic modeling framework I developed for analyzing single-cell population data across perturbations at scale (PopAlign). PopAlign models single-cell data with semantically interpretable, low-error, highly-compressed probabilistic models, which allows fast comparisons across hundreds of samples. In the second part, I will discuss how I applied this framework to analyze a drug response study of over 1.6M human primary immune cells to 500 commercially-available immunomodulatory compounds. While most compounds in the library exert broad impact across multiple cell types in the population, my analysis also reveals highly cell-type specific activity, including a novel myeloid-suppressing function of a group of compounds including NSAIDs and an artificial sweetener. My work provides new depth and insight into how existing compounds reshape immune populations, and a general platform for evaluating and designing population-level responses to therapeutic interventions.

ESE Seminar: "Sensing the Physical World using Pervasive Wireless Infrastructure"
2021-02-25 11:00 - 12:00 | Zoom – Email ESE for Link jbatter@seas.upenn.edu
Emerging applications such as smart cities, autonomous vehicles, and mixed reality rely on embedded systems that are engaging with the physical environment through sensors. Building upon this connection, my vision is to advance Omnipresent Sensing by harnessing the wireless infrastructure in and around buildings and cities to act as a non-intrusive sensing platform. This is possible by innovating at the crossroads of two recent trends in mobile computing: (1) Wireless technologies such as Millimeter-wave (mmWave) and Massive MIMO systems can now support higher bandwidth for communication and improved resolution for RF sensing applications. (2) Advancements in CPUs and RF front-ends are making it easier to develop software-defined sensing and communication systems. This is affording edge devices the ability to do more advanced signal processing and machine learning.
In this talk, I will focus on how to design an RF-equivalent of optical retro-reflectors and use them as fiducial markers in autonomous vehicles, robotics, and mixed reality applications. I will then discuss how nuances from the environment itself can be leveraged to improve sensing quality in the context of human sensing, object tracking, and indoor localization. I will conclude this talk with a roadmap of combining radar-style RF sensors and wireless communication links for the wireless embedded systems of the future.

MSE Seminar: "Harnessing Temporally Controlled Biophysical Cues To Direct Stem Cell Phenotype"
2021-02-25 10:45 - 11:45 | PA
Endogenous tissue-specific stem cells are crucial regulators of tissue health throughout life, orchestrating diverse functions ranging from learning and cognition to skeletal muscle homeostasis. The local microenvironment, or stem cell niche, presents a myriad of biochemical and biophysical factors that direct cell fate. Stem cell mediated tissue regeneration relies on presentation of these factors in a precise temporal sequence at appropriate doses. Dysregulation of this process, such as in aging and disease, leads to diminished tissue function and potentially organ failure. Despite the known importance of biophysical cues in regulating stem cell phenotype, the effects of temporal changes in the mechanical and microstructural properties of the extracellular matrix (ECM) on stem cell fate remain poorly understood, in large part due to a lack of suitable engineered systems to selectively probe how changing matrix properties impact cellular signaling. In my talk, I will describe a multifaceted strategy to elucidate unappreciated mechanisms behind cell-ECM interactions impacting homeostasis and disease, drawing on protein engineering, bioorthogonal chemistries, and stem cell biology. In the first half of the talk, I will discuss the use of protein engineered biomaterials to identify critical ECM properties that are required for neural stem cell expansion. The second half of the talk will focus on the development of bioorthogonal chemical strategies to regulate the mechanical properties of synthetic cell culture substrates on demand and the application of these materials to determine how temporally varying matrix properties impact muscle stem cell commitment. Together, these research projects highlight the power of engineered platforms in elucidating novel biological mechanisms implicated in development, disease, and aging.

Inaugural Joseph Bordogna Forum: “A Call to Action for Racial Justice and Equity in Engineering”
2021-02-24 16:00 - 17:30 | https://upenn.zoom.us/j/96715197752
Racism and anti-Blackness are crises that jeopardize our democracy, productivity and well-being and call into question whether we can all live together peaceably and harmoniously in a just and equitable American society. At this critical moment in our nation’s history we need more than words that renounce racism and anti-Blackness, we need actions to abolish them.
We must be willing to have meaningful and difficult conversations if we are to rid ourselves of the fear of the other, the yoke that prevents us from becoming a nation where everyone is treated with dignity and respect. Engineers must be at the table where these conversations take place.
In this lecture, Dr. Slaughter will discuss the social responsibilities that engineers have in making the world a more equitable place and the solutions that corporations and academic institutions can enact to create lasting and meaningful change.
Zoom Link | Password: [REDACTED]

Spring 2021 GRASP SFI: “Hunting for Unknown Unknowns: AI and Ethics in Society”
2021-02-24 15:00 - 16:00 | Zoom
Abstract: Homo Sapiens is considered a “hyper-cooperative species,” and this aptitude for cooperation may be responsible for our dominance over the Earth. Cooperation promises great benefits, but each participant is vulnerable to exploitation by their partners. Successful cooperation requires trust: acceptance of vulnerability, with confidence that it will not be exploited. The culture of any society includes ethical principles specifying how to be trustworthy, to whom trustworthiness is owed, and how to recognize who is likely to be trustworthy. The continued viability of a society depends on how well this mechanism does its job. Deployments of AI systems for autonomous vehicles, facial recognition, medical diagnosis, decisions about credit or parole, and other domains have raised questions about their trustworthiness. These questions apply not only to robotic and AI systems based on digital computers, but also to institutional structures such as governments and corporations. Trust failures arise when a carefully designed decision mechanism confronts a situation outside its comprehension: an “unknown unknown.” Science, engineering, economics, law, and public policy all depend on models to cope with the unbounded complexity of the real world. A model specifies a limited set of elements and relations that support inferences relevant to the purpose of the model. Everything else is considered negligible relative to the purpose of the model. If some of these unknown unknowns stop being negligible, the model can fail, possibly with serious consequences. Game-theoretic reasoning, maximizing expected utility, can be a powerful decision tool in multi-agent settings, but its validity depends critically on the quality of the model, especially the definition of utility. A particular failure mode, when the utility measure is oblivious to trust and trustworthiness, is to encourage each participant to optimize expected utility by exploiting the vulnerabilities of the other participants. Trust and cooperation are thereby discouraged. Widespread loss of trust and cooperation can become an existential threat to the society. Our task in AI is to identify potentially dangerous unknown unknowns, and find appropriate ways to incorporate them into our models, supporting trust and cooperation in our society.
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CIS Seminar: "Enhancing Usability and Explainability of Data Systems"
2021-02-24 15:00 - 16:00 | Zoom – Email CIS for link, cherylh@cis.upenn.edu
The recent growth of data science has expanded its reach to an ever-growing user base of non-experts. Unfortunately, most existing systems offer limited usability and support for explanations: these systems are usable only by experts with sound technical skills, and even experts are hindered by the lack of transparency into the inner workings of the systems. My research focuses on solving the challenges users face while interacting with data systems and, thus, pushes the frontiers towards achieving democratization of data systems, demanding that people with different skills and backgrounds should be able to use these data systems alike. Further, my research aims at providing explainability of the behavior of data systems to help the users understand and trust the system function, especially when unexpected behavior occurs. In this talk, I will discuss frameworks that address these challenges in a variety of settings and applications, including relational data querying, document summarization, system debugging, and trust in machine-learning models that learn from data.

CBE Seminar: "Probing Protein Interactions from Molecular to Cellular Scales with Microscale Technologies"
2021-02-24 15:00 - 16:00 | Zoom – Email CBE for link
Abstract
Biological molecules rarely act alone. For example, in many pediatric cancers, a chromosomal rearrangement results in a fusion protein with altered DNA and protein interactions that yield proliferative and aggressively metastatic cell subpopulations. In this talk, I will describe quantification of molecular interaction properties relevant to fusion oncoprotein biology using microscale tools with distinct forces tailored to each biological question. First, I will discuss measurement of cellular heterogeneity in cytoskeletal protein complex abundance as is needed to uncover ‘rogue’ metastatic and drug resistant cells. I introduced a microfluidic biochemical assay using electrophoretic forces and sieving hydrogels to fractionate dynamic protein complexes from single cells faster than dissociation kinetics. Second, I will describe biophysically probing protein-DNA molecular mechanics to understand how tension plays a role in DNA pairing during DNA damage repair. To reveal forces the Rad51 repair protein exerts on DNA, microscale tweezers apply a magnetic piconewton-scale force to single molecules of DNA. Finally, I will share future directions discerning the biochemical and biophysical roles of multi-component protein complexes in fusion oncoprotein-driven pediatric cancers, such as Ewing’s sarcoma. My group will uncover new targets for ‘molecularly surgical’ Ewing’s sarcoma therapies through interrogation of molecular interactions towards replacing combination chemotherapy and crude tumor removal surgeries.

CIS Seminar: "Provably Secure Indistinguishability Obfuscation"
2021-02-23 15:00 - 16:00 | Zoom – Email CIS for link, cherylh@cis.upenn.edu
Abstract:
In this talk, we will cover some exciting progress on the problem of Indistinguishability Obfuscation (proposed by Barak et. al. 2001). In a nutshell, an Indistinguishability Obfuscation scheme is an efficient compiler that takes as input a program and outputs a new program with the same input-behavior and only a polynomial slowdown, but in addition, we have the guarantee that the new program reveals minimal information about the original program.
If realized securely and efficiently, such an obfuscation scheme would have huge consequences to both theory and practice. However, until now we did not know if it exists under any reasonably well-believed conjecture. Our work places iO onto “terra-firma”, by giving a construction that is as secure as several well-studied mathematical problems that are widely believed to be extremely hard to solve.
In this talk, we will hear about indistinguishability obfuscation, why it is useful, how it can be constructed, and future work.

MEAM Seminar: "Engineering Interfaces To Improve The Thermal Performance of Wide Bandgap Semiconductors"
2021-02-23 10:30 - 12:00 | Zoom – Email MEAM for Link, peterlit@seas.upenn.edu
Wide bandgap electronics are currently under development due to their potential to create some of the most advanced RF and power electronics in the world. A key concern in their development is the control of the junction temperature during operation which is impacted by the internal device thermal resistance. To address this concern, we will discuss advancements in thermal characterization techniques that have allowed new insights into the role of material interfaces on the thermal response of electronic devices made from GaN, AlGaN, and Ga2O3. While combining these semiconductors with high thermal conductivity like AlN, SiC or diamond have promise for improving heat dissipation, manufacturing challenges exist that must be addressed. We will discuss a few of these methods of integration ranging from direct growth to plasma activated bonding. Finally, for power electronics, packaging solutions for the thermal management of ultrawide bandgap devices will be presented, allowing for the future implementation of this technology.

BE Dissertation Defense: "Microtissue Engineered Neural Networks as Optically-Controlled Living Electrodes for Circuit Modeling and Neuroprosthetics" (Dayo Adewole)
2021-02-22 09:00 - 11:00 | PA
The Department of Bioengineering at the University of Pennsylvania and Dr. D. Kacy Cullen are pleased to announce the Doctoral Dissertation Defense of Dayo Adewole.

Title: Microtissue Engineered Neural Networks as Optically-Controlled Living Electrodes for Circuit Modeling and Neuroprosthetics

Date: February 22, 2021
Time: 9:00am

Please join via the zoom link below:

https://zoom.us/j/2559106703?pwd YVFuVkxsZDk2NGRJU0tzREh3SDUzQT09

The public is welcome to attend.

PICS Colloquia: "Recent Advances in Modeling Subduction and Viscoelastic Flow in Geodynamic Computations"
2021-02-19 14:00 - 15:00 | Zoom – email kathom@seas.upenn.edu
Abstract: We will describe two separate but related methodologies that have been implemented in the open source, finite element code ASPECT, which computational geophysicists use to model a wide variety of problems that arise in Earth and Planetary geophysics. The first technique is a volume-of-fluid (VOF) interface tracking algorithm that was originally designed to model the subduction of the oceanic lithosphere of a tectonic plate beneath a less dense lithosphere of a second plate. However, we have since used this VOF methodology to model some basic laboratory experiments in order to benchmark some of the rheological models that have been implemented in ASPECT. The second technique is the particle or particle-in-cell (PIC) methodology, which we have been developing and benchmarking for use in ASPECT for the past seven years or so. This PIC methodology has been shown to have excellent weak and strong scaling over at least three orders of magnitude of model size on a uniform grid. In addition, our PIC algorithm shows that strong scaling for the adaptive grid case is nearly as good as for the uniform grid case, decreasing the total runtime essentially linearly from 96 to 3,072 cores. We will briefly show a collection of benchmarks we have used and developed to assess the accuracy of this PIC methodology and conclude with a description and video of a beam bending in a less dense viscoelastic medium due to the force of gravity in which the viscoelastic rheology is modeled by the components of stress that are carried on the particles and interpolated onto the underlying finite element grid at each time step.

ODEI Spotlight: A Conversation with Stacey Abrams
2021-02-19 12:00 - 13:30 | PA
Please join us on February 19th at noon EST for a conversation with Stacey Abrams, moderated by Benjamin Todd Jealous and with remarks from President Amy Gutmann.
The event is sponsored by the Annenberg School for Communication, the University of Pennsylvania Carey Law School, the Stavros Niarchos Foundation Paideia Program, and the Penn Provost’s Office.
Register Here.
If you would like to ask Stacey Abrams a question at the event, please submit it in advance using this link.
