Feb 24, 2017
Lopata Hall, Room 101
"Topology-controlled Reconstruction of Multi-labelled Domains from Cross-sections"
Adviser: Tao Ju
In this work we present the first algorithm for reconstructing multi-labeled material interfaces the allows for explicit topology control. Our algorithm takes in a set of 2D cross-sectional slices (not necessarily parallel), each partitioned by a curve network into labeled regions representing different material types. For each label, the user has the option to constrain the number of connected components and genus. Our algorithm is able to not only produce a material interface that interpolates the curve networks but also simultaneously satisfy the topological requirements. Our key innovation is defining a space of topology-varying material interfaces, which extends the family of level sets in a scalar function, and developing discrete methods for sampling distinct topologies in this space. Besides specifying topological constraints, the user can steer the algorithm interactively, such as by scribbling. We demonstrate, on synthetic and biological shapes, how our algorithm opens up new opportunities for topology-aware modeling in the multi-labeled context.
"Secure Dynamic Authentication of Passive IoT Devices Using Self-powered FN Tunneling Timers"
Adviser: Shantanu Chakrabartty
A major limitation in authenticating passive and remotely powered sensors, tags and cards (for e.g. radio-frequency identification tags or credit cards) is that these devices do not have access to a continuously running system clock. This obviates the use of SecureID type authentication techniques involving random keys and tokens that need to be periodically generated and synchronized. In this work we present a dynamic hardware-software authentication approach for passive assets using zero-power timers and synchronization circuits.
The timers are shown to achieve robust temporal synchronization due to the self-powering and self-compensating physics of Fowler-Nordheim (FN) quantum transport of electrons tunneling onto a floating-gate. The output of the timers can then be used to seed a pseudo-random number generator which produce random and synchronized authentication tokens. We validate the proposed approach using prototypes fabricated in a standard 0.5$\mu$m CMOS process where we demonstrate synchronization accuracy greater than 40dB.
Compared to conventional static authentication methods that are currently used for passive sensors, tags and cards, the proposed dynamic approach should provide enhanced security and make it more immune to counterfeiting and data theft.