Penn Engineering Events

MEAM Seminar: "Viewing Earth's Surface as a Soft Matter Landscape"
2019-01-22 10:45 - 11:45 (America/New_York) | Wu and Chen Auditorium (Room 101), Levine Hall, 3330 Walnut Street, Philadelphia, PA, 19104, United States
The Earth’s surface is composed of a staggering diversity of particulate-fluid mixtures: dry to wet, dilute to dense, colloidal to granular, attractive to repulsive particles, laminar to turbulent flows, and steady to highly-unsteady forcing. This material variety is matched by the range of relevant stresses and strain rates, from rapid and catastrophic landslides to the slow relaxation of soil over geologic timescales. In this talk I illustrate the commonalities and challenges in understanding geophysical flows by highlighting two problems: gravity-driven downslope soil movement, and fluid-driven particle transport in rivers.
Soil on hillslopes slowly and imperceptibly creeps downhill, but suddenly liquefies to produce landslides. The transition between creeping and flowing is a yield condition, often defined in terms of the shear stress, that depends on the characteristics of the soil and the geologic environment. We show that the nature of this transition, however, is general. Creep is the localized and erratic motion of soil grains below yield; because this kind of fragility is a generic consequence of disorder, soil creep should be similar to amorphous glass. Indeed, we find that the transition from creeping to landsliding is a continuous phase transition that follows predictions from glass transition models. The generality of this transition suggests that the onset of sediment transport in rivers should behave in a similar manner, and we demonstrate that this is the case using laboratory experiments and simulations. Because the sediment transport rate rapidly increases for stresses above yield, many landscapes such as rivers organize to be close to the yield point. In essence, landscapes flicker back and forth across the glass transition. We explore several consequences of these dynamics for the sculpting of landscapes.

CIS Seminar: "What Should We Do With Persistent Main Memory?"
2019-01-17 15:00 - 16:00 | Wu and Chen Auditorium (Room 101), Levine Hall, 3330 Walnut Street, Philadelphia, PA, 19104, United States
Memory systems are on the verge of a renaissance: Scalable, persistent main memories (e.g., Intel’s 3DXPoint) are the first new technology to enter the upper layers of the memory hierarchy in 50 years. They bring a fundamentally new capability (i.e., persistence), a dramatic increase in capacity, and an array of complications (e.g., asymmetric read and write performance, power limitations, and wear out). This combination of characteristics raises a deceptively simple but fundamental question: What should we do with persistent main memory? In this talk, I will describe several potential answers and the systems my group has built to help understand how different answers affect performance, programmability, and other aspects of system design. I’ll also highlight the central challenges that these memories present and try to summarize what we have learned about them. Finally, I’ll describe what I see as the most interesting avenues for future work.

ESE Seminar: "Towards a Seamless Integration of Drones in Smart Cities: Communications and Security"
2019-01-17 11:00 - 12:00 | Room 337, Towne Building, 220 South 33rd Street, Philadelphia, PA, 19104, United States
The use of unmanned aerial vehicles (UAVs), popularly known as drones, will be an integral component of emerging smart city applications ranging from delivery of goods to flying taxis. However, a seamless deployment of such drone-based applications requires addressing technical challenges across communications, security, autonomy, and control. In this talk, we focus on the wireless communications and security challenges of drone-based systems. From a communications perspective, UAVs can assume two roles: aerial base stations that enhance the coverage and capacity of wireless networks and flying users that require wireless cellular connectivity for enabling applications such as real-time streaming and item delivery. With this in mind, we introduce a foundational framework for designing three-dimensional (3D) wireless cellular networks that incorporate both drone base stations and cellular-connected drone users. For this novel 3D model, we study a number of key problems including drone deployment, network planning, and cell association. Then, we turn our attention to the cyber-physical security challenges brought forward by the deployment of drones. In this area, we present a holistic framework, with foundations in behavioral game theory, for addressing fundamental cyber-physical security problems pertaining to drone-based systems. In particular, we show how notions of risk, bounded rationality, and uncertainty can influence the security of drone-based systems and we develop new game-theoretic solutions that explicitly account for such factors in security analyses. We conclude by an overview on our ongoing research activities that cut across the areas of cyber-physical systems, wireless networks, game theory, machine learning, security, and control.

MSE Seminar: "Respectful Workplaces + Implicit Bias"
2019-01-17 10:45 - 11:45 | Auditorium, LRSM Building, 3231 Walnut Street, Philadelphia, PA, 19104, United States

MEAM Seminar: "Stretching the Boundaries of Medical Robotics"
2019-01-15 10:45 - 11:45 | Wu and Chen Auditorium (Room 101), Levine Hall, 3330 Walnut Street, Philadelphia, PA, 19104, United States
Abstract: My lab creates medical robots not only for minimally invasive surgery, but also for targeted drug delivery and for tissue regeneration. This talk will describe three of our technologies. The first consists of tetherless robots that are powered, controlled and imaged using an MRI scanner. These devices vary from patient-mounted needle-driving robots to capsules that can move inside fluid-filled body lumens. The second technology consists of a class of robot implants designed to apply traction forces over a period of weeks inside the body so as to induce the regeneration of soft tissues. Applications include lengthening the esophagus and bowel for the treatment of congenital defects and disease. The third is a type of continuum robot that is based on concentrically combining pre-curved superelastic tubes. We are using this technology to create multi-armed systems for intracranial endoscopic surgery. We are also developing endoscopically-guided catheters that can navigate autonomously inside the blood-filled beating heart.

REACT@Penn 2019: Policy, Technology and Science for Global Challenges
2019-01-14 11:30 - 15:30 | Perry World House, 3803 Locust Walk, Philadelphia, PA, 19104, United States
This REACT@Penn meeting will be at the Perry World House and will bring together policy experts and researchers around the global challenges of water, energy and health. Registration is free, but please register in advance.
