Abstract: Quadrotors and multirotors in general are common in many inspection and surveillance applications. For these applications, visual-inertial odometry is a common way to localize the vehicles and observe the environment. However, unlike with wheeled mobile robots, quadrotor localization algorithms often do not use knowledge of the control inputs and the full vehicle dynamics as […]
Our group at the University of Minnesota focuses on fundamental advances in numerical algorithms, and understanding of flow physics that allow the prediction of engineering turbulent flows. This presentation will discuss key aspects of such simulation alongside illustrative examples. We will discuss a recently developed unstructured overset grid methodology and its application to particle-resolved DNS […]
Abstract : Optically active spins in solids offer exciting opportunities as scalable and feasible quantum-optical devices. Numerous material platforms including diamond, semiconductors, and atomically thin 2d materials are under investigation, where each platform brings some advantages of control and feasibility along with other challenges. The inherently mesoscopic nature of solid-state platforms leads to a multitude of […]
Abstract: The ability to integrate dissimilar materials with different crystal structures and properties enables heterostructures to be developed with new functionality well beyond the normal band gap engineering offered by semiconductor heterostructures. The combination of metals, semiconductors, insulators, magnetic, piezoelectric, structural and phase change materials offers the potential for nearly limitless control of device properties. […]
Abstract: Since Dow first formed a global reaction engineering discipline over twenty years ago, we have accumulated much experience leading and supporting a diversity of reaction engineering projects for our corporation. This presentation will provide specific examples of real-world reaction engineering problems at Dow in the past 27 years and summarize our perspective regarding the […]
The rapidly diversifying face of colleges and universities in the United States including the University of Pennsylvania require that we are able to manage intercultural relationships from different backgrounds. We are all working in a multicultural institution, with students, faculty and staff from all over the world. This makes for a very diverse, vibrant community […]
Rapid, quantitative molecular diagnostics in the field, at home, and in resource poor settings is needed for evidence-based disease management, control, and prevention. Conventional molecular diagnostics requires extensive sample preparation, sophisticated instruments, and trained personnel, restricting their use to centralized laboratories. To overcome the limitations of laboratory-based procedures, we designed a simple, inexpensive, hand-held, smartphone-based […]
Abstract Two recent advancements of high-order spectral difference (SD) method for computational fluid dynamics on unstructured meshes will be presented. The first progress is our contribution to a new curved sliding-mesh approach to the SD method for simulating flapping and rotary wing aerodynamics. The second elevation of the SD method is our recent successful design […]
Variable geometry “morphing” structures can achieve different geometric configurations through overall deformation, but usually many actuators are required for shape control. In this talk we consider a particular type of morphing structure that is able to switch configuration with only a few actuators. It is based on the concept of embedding by design local energy […]
Modern image sensors consist of systems of cascaded and bulky spherical optics for imaging with minimal aberrations. While these systems provide high-quality images, the improved functionality comes at the cost of increased size and weight. One route to reduce a system’s complexity is via computational imaging, in which much of the aberration correction and functionality […]
Abstract: With the ongoing, frequent disclosure of the existence and exploitation of security vulnerabilities, one might wonder: How can we can build software that is more secure? In an attempt to focus educational attention on this question, and gather empirical evidence at the same time, we developed the Build it, Break it, Fix it (BIBIFI) […]
Abstract: Despite their promise to mitigate many problems and offer new opportunities in energy storage systems, nanomaterials have proven to be difficult to tailor and preserve their assembly throughout manufacturing processes when a scale-up is considered. My group has been working on understanding and modification of instability-driven processes to devise scalable manufacturing processes such as […]
The classical paradigm of tissue engineering involves the integrated use of human stem cells, biomaterial scaffolds (providing a structural and logistic template for tissue formation) and bioreactors (providing environmental control, dynamic sequences of molecular and physical signaling, and insights into the structure and function of the forming tissues). This “biomimetic” approach results in an increasingly […]
Abstract: Blood clot formation involves the coupled processes of platelet aggregation and coagulation, which are triggered when there is break in a blood vessel. Platelet aggregation is largely a physical process while coagulation is biochemical, consisting of a large network of reactions that culminate in the generation of the enzyme thrombin. Thrombin cleaves fibrinogen into […]
Physical connectors with self-aligning geometry aid in the docking process for many robotic and automatic control systems such as robotic self-reconfiguration and air-to-air refueling. This self-aligning geometry provides a wider range of acceptable error tolerance in relative pose between the two rigid objects, increasing successful docking chances. In a broader context, mechanical alignment properties are […]
Abstract: At a time when computing is so much a part of all of our lives, has incredible job opportunities, and is so empowering, most students graduate high school without having had any introduction to computer science. A decade ago in the United States, the CSforALL movement was launched to broaden participation in computing to those traditionally underrepresented. This talk will […]
Abstract: Despite the provision of a $380M federal grant to enhance technology and improve security in the 2018 midterm elections, machine failures and computer malfunctions again plagued polling places (in GA, PA, NY, IN, TX, and MA), resulting in late openings, long lines, and turned-away voters. Poor ballot layouts resurfaced in Florida, resulting in nearly […]
Due to the inherent planarity of conventional micro and nanofabrication, it is challenging to pattern and assemble micro, bio, and nano-materials and devices in all three dimensions. Origami inspired mechanical assembly by curving, bending, and folding of appropriately designed micro and nanopatterned precursors provides a high-throughput solution to address this challenge. In this talk, I […]
Abstract: Wireless sensors and edge-cloud analytics have the potential to gather and process vast amounts of data about the physical world, offering radical new insights about everything from critical infrastructure to interpersonal interactions. But designing, deploying, and operating geographically-distributed systems consisting a hierarchy of sensing, storage, compute, and communication elements raises interesting new challenges across […]
Abstract: Quantum computing promises exponential speedups for an important class of problems. While quantum computers with few dozens of qubits have been demonstrated, these machines suffer from high rate of gate errors. Such machines are operated in the Noisy Intermediate Scale Quantum (NISQ) mode of computing where the output of the machine can be erroneous. […]
Title: "Data-Driven Modeling, Analysis and Design of Networked Dynamical Systems with Applications in Neuroscience" Abstract: In this thesis, we provide contributions to the modeling, analysis and design of networked dynamical systems from a data-driven perspective. Our approach is grounded on the integration of concepts and tools from graph theory, control theory, optimization, and statistics. In […]
Abstract: Understanding and harnessing the coupling between lubrication pressure, elasticity, and surface interactions provides materials design strategies for applications such as adhesives, coatings, microsensors, and biomaterials. This presentation will discuss our efforts to understand how soft materials make contact and adhere under dynamic conditions in fluid environments. Measurements of interactions between soft surfaces will show how […]
Symmetry and topology are fundamental notions existing in all kinds of natural systems, from spiral galaxies and hurricanes to amino acids in molecules and non-trivial topologically protected electronic states in condensed matter. A stream of photons is typically topologically trivial, nevertheless, its full-vector nature intrinsically endows light with full capability of creating and carrying unique […]
In the last 20 years, microfabrication techniques have allowed researchers to miniaturize tools for a plethora of bioanalytical applications. In addition to better sensitivity, accuracy and precision, scaling down the size of bioanalytical tools has led to the exploitation of new technologies to further manipulate biomolecules in ways that has never before been achieved. For […]
Abstract: Cryptocurrencies and blockchains are often heralded as the keys to a new era of financial transparency and fairness. Decentralized exchanges (DEXes), in particular, run directly on blockchains. They manage custody of traded assets, preventing theft by exchange operators, and provide a globally visible and accessible trading platform that seems egalitarian. Our research, though, has revealed that DEXes […]
Abstract: Organic molecular crystals frequently exist in multiple forms known as polymorphs. Structural differences between crystal polymorphs can affect desired properties, such as bioavailability of active pharmaceutical formulations, lethality of pesticides, or electrical conductivity of organic semiconductors. Crystallization conditions can influence polymorph selection, making an experimentally driven hunt for polymorphs difficult. Such efforts are further […]
Title: "Towards Advanced Photonic Integrated Systems through Electronic-Assisted Design" Abstract: Optical systems have applications ranging from traditional areas such as communication and spectroscopy to emerging fields such as quantum computing and cryptography. Bench-top optical systems, using free-space optics or fiber optics with standalone devices, have been successful. However, they tend to occupy a large space […]
Committee: Daeyeon Lee, PhD and Shu Yang, PhD, Co-Advisors; Kathleen Stebe, PhD and Amish Patel, PhD
Recent developments in nanostructured materials have demonstrated myriad desirable properties ranging from optical and mechanical metamaterials to biomanipulative surfaces. To bring these properties from the lab to the commercial space will require innovative nanomanufacturing strategies focused on scalable and cost-effective techniques. My lab, the Hybrid Micro/Nanomanufacturing Laboratory, applies the manipulation of fundamental driving forces to […]
Abstract: Hyperscale datacenters provide critical infrastructure for the information economy, refining data to extract value. Sharing datacenters improves energy efficiency but whether strategic users participate depends on management policies. I address these challenges by integrating practical insights from computer architecture with rigorous methods in algorithmic economics and machine learning. I illustrate this approach for power allocation […]
