The Beckman Institute Graduate Student Seminar Series presents the work of outstanding graduate students working in Beckman research groups. The seminars begin at Noon in Beckman Institute Room 1005 and are open to the public. Lunch will be served.

Saliency Detection via Divergence Analysis: A Unified Perspective
Jia-Bin Huang

We present a unified view that frames various bottom-up saliency detection algorithms. As these methods were proposed from intuition and principles inspired from psychophysical studies of human vision, the theoretical relations among them are unclear. In this talk, we propose such a bridge. The saliency is defined in terms of divergence between feature distributions estimated using samples from center and surround, respectively. We explicitly show that these seemly different algorithms are in fact closely related. We also discuss some commonly-used center-surround selection strategies. Comparative experiments on two publicly available datasets are presented to further provide insights on relative advantages of these algorithms.

Multifunctional Composites from Three-Dimensional Microvascular Structures
Hefei Dong

This presentation highlights the new technique we developed to create three-dimensional microvascular structures within a traditional composite using sacrificial fibers. This technique relies on the efficient thermal depolymerization of catalyst-impregnated polylactide (PLA) fibers with simultaneous evaporative removal of the resulting lactide monomer. The hollow channels produced are high-fidelity inverse replicas of the original fiber's diameter and trajectory. The method has created microvascular materials with channels over one meter in length that can be subsequently filled with a variety of liquids including aqueous solutions, organic solvents for applications such as self-healing and thermal management. Current efforts focus on expanding the technique to various matrices as well as architectures of sacrificial components.

A history of mild traumatic brain injury is associated with reduced neural activity and memory impairment later in life
Jim Monti

Evidence suggests that a history of head trauma is associated with memory deficits later in life. This study sought to understand the neural basis of this memory deficit by comparing young and middle-aged adults who have had a mild traumatic brain injury in their recent and remote past, respectively, with control subjects while performing a memory paradigm during functional magnetic resonance imaging. Results indicated middle-aged adults with a head injury in their remote past have impaired memory and reduced neural activity in cortical regions important for declarative memory and implicated in Alzheimer’s disease.