A structure from motion inequality

We state an elementary inequality for the structure from motion problem for m cameras and n points. This structure from motion inequality relates space dimension, camera parameter dimension, the number of cameras and number points and global symmetry properties and provides a rigorous criterion for which reconstruction is not possible with probability 1. Mathematically the inequality is based on Frobenius theorem which is a geometric incarnation of the fundamental theorem of linear algebra. The paper also provides a general mathematical formalism for the structure from motion problem. It includes the situation the points can move while the camera takes the pictures.Comment: 15 pages, 22 figure

Space and camera path reconstruction for omni-directional vision

In this paper, we address the inverse problem of reconstructing a scene as well as the camera motion from the image sequence taken by an omni-directional camera. Our structure from motion results give sharp conditions under which the reconstruction is unique. For example, if there are three points in general position and three omni-directional cameras in general position, a unique reconstruction is possible up to a similarity. We then look at the reconstruction problem with m cameras and n points, where n and m can be large and the over-determined system is solved by least square methods. The reconstruction is robust and generalizes to the case of a dynamic environment where landmarks can move during the movie capture. Possible applications of the result are computer assisted scene reconstruction, 3D scanning, autonomous robot navigation, medical tomography and city reconstructions

The Murderers: Agamemnon & Electra Poster

Providence College Department of Theatre, Dance & Film Blackfriars Theatre The Murderers: Agamemnon & Electra, by Aeschylus & Sophocles Thursday-Saturday, April 10-12, 2003, 8pm Sunday, April 13, 2003, 2pm Poster by Chris Herranhttps://digitalcommons.providence.edu/murderers_pubs/1000/thumbnail.jp

SEM/EDX Chemical Composition Map of Mastodon Tusk

The goal of this project was to study one of the rarest objects in the collection of the UNI museum dating to the Aftonian or Yarmouth age (around 120,000 to 200,000 years old). The tusk is 11 feet, 7.5 inches with a circumference at the proximal end of 2 feet, 2 inches. There have been previous attempts of restoration of this tusk but there are not specific procedures on record that specify the materials or methods used during the restoration attempts with sufficient detail. With the support of the Carver Grant awarded to the UNI museum, research teams containing students from the chemistry, geology, history, art and anthropology departments will contribute to the study and preparation for the final restoration of the tusk. The first phase of the project consists in the determination of the materials used to in the past restorations attempts. There are a variety of subprojects using different instruments and analytical techniques to achieve this goal. For this part of the project, a chemical map of the tusk was generated using the Evex Mini SEM/EDX.https://scholarworks.uni.edu/mastodon_posters/1002/thumbnail.jp

Spring Dance Concert 2003 Poster

Providence College Department of Theatre, Dance & Film Blackfriars Theatre Spring Dance Concert 2003 (Blackfriars Dance Concert) Saturday, April 26, 2003, 8pm Sunday, April 27, 2003, 2pm Poster by Chris Herranhttps://digitalcommons.providence.edu/bdc_2003_pubs/1003/thumbnail.jp

Waiting for Godot Poster

Providence College Department of Theatre, Dance & Film Blackfriars Theatre Waiting for Godot, by Samuel Beckett Friday & Saturday, February 14 & 15 and 21 & 22, 2003, 8pm Sunday, February 16 & 23, 2003, 2pm Poster by Chris Herranhttps://digitalcommons.providence.edu/godot_pubs/1000/thumbnail.jp

Engineering plasmonic bimetallic nanostructures for energy conversion

A new class of photocatalysts gathering both optical and heterogeneous catalysis principles can be produced by combining plasmonic nanoparticles with catalytic metals. In this configuration, chemical reactions taking place in the catalytic comoonent are powered by the visible light focused by plasmonic nanoparticles. Understanding how energy is transferred from the plasmonic to the catalytic reactive center, necessary to maximize the benefits of this combination, is one of the main concerns of these hybrids. Excited carriers, electromagnetic fields, and even heat are essentially the means by which the energy can be delivered to the reactive center. These pathways strongly depend on how the materials interact; for instance, charge transfer or heat transfer pathways require the presence of an interface, while other pathways need the construction of a gap between the components. It is central to determine which of these pathways modulates the performance of plasmonic bimetallic photocatalysts in order to obtain the maximum efficiency on converting light into chemical energy. In this regard, the following aspects of plasmonic bimetallic systems were investigated in the course of this thesis: • The structure-performance correlation • Ability to convert light into heat • The transition from a colloidal suspension to a 2D planar configuration with optimized geometry, boosting the light-catalyst interaction. Our observations point out that those structures in which the catalytic metal is positioned at sub-nanometer distance with respect to the plasmonic nanoparticle (antenna-reactor), are able to produce a higher boost in reaction rates. In addition to the little detriment of the optical properties, the plasmonic nanoparticles are able to increase the otherwise small absorption of the catalytic metals in the visible range via optical hotspots formation. As a result of the interaction with light, excited carriers are generated in proximity to the adsorbate-reactor interface, where can be utilized for the adsorbed molecules to facilitate their transformation. Thermal analysis proved that the plasmonic antenna’s heat output is insufficient to account for the reaction boost at solar irradiances, which allowed us to conclude that the excited carriers are a significant factor in the rate enhancement. Finally, the preferred conformation was extended as a 2D supercrystal offering a large density of hotspots which catalytic metals can take advantage from. When testing this structure for Formic Acid dehydrogenation, it resulted in one of the largest production reported so far for this H2 carrier