Blind Deconvolution through Polarization Diversity of Long Exposure Imagery

The purpose of the algorithm developed in this thesis was to create a post processing method that could resolve objects at low signal levels using polarization diversity and no knowledge of the atmospheric seeing conditions. The process uses a two-channel system, one unpolarized image and one linearly polarized image, in a GEM algorithm to reconstruct the object. Previous work done by Strong showed that a two-channel system using polarization diversity on short exposure imagery could produce images up to twice the diffraction limit. In this research, long exposure images were simulated and a simple Kolmogorov model used. This allowed for the atmosphere to be characterized by single parameter, the Fried Parameter. Introducing a novel polarization prior that restricts the polarization parameter, it was possible to determine the Fried Parameter to within half a centimeter without any addition knowledge or processes. It was also found that when high polarization diversity was present in the image could be reconstructed with significantly better resolution and signal level did not affect this resolving capability. At very low signal levels, imagery with low to no diversity could not be resolved at all whereas high diversity resolved equally as well as if there was a high signal level. Current algorithms being used do not include polarization diversity but can substantially improve resolution. Application of this algorithm could be used in dim-object detection around satellites as well as solar surface imagery

Building a Conceptual Model to Define the F-22 Supply Support Decision Process

The Air Force requires a method to determine the most effective and efficient means of supply support for new weapon system acquisitions. This study is a qualitative research effort that examines this requirement in an environment that embraces interim contractor support for the F-22. A series of six propositions are suggested to incorporate in the supply support decision-making process. A conceptual model is developed from these propositions to describe the process for determining the optimal timeframe for making long term supply support decisions. A systems approach to project management is used as the vehicle for this process, and the F-22 Supply Support Integrated Product Team is the driver. Weapon system stability/maturity is contemplated as one of the input parameters, and a definition of stability is presented. Judgment will be a major factor in the ultimate supply support decision due to the lack of available system tools to accurately predict the most appropriate timeframe. The most important recommendation is that the process of evaluation should begin immediately. Familiarity will increase knowledge and experience as team members are exposed to this emerging concept. Due to the novelty of this topic, this research documents the deficiency in this area and lays a cornerstone for future research

Population response of triploid grass carp to declining levels of hydrilla in the Santee Cooper Reservoirs, South Carolina

Approximately 768,500 triploid grass carp ( Ctenopharyngodon idella Valenciennes) were stocked into the Santee Cooper reservoirs, South Carolina between 1989 and 1996 to control hydrilla ( Hydrilla verticillata (L.f.) Royle). Hydrilla coverage was reduced from a high of 17,272 ha during 1994 to a few ha by 1998. During 1997, 1998 and 1999, at least 98 triploid grass carp were collected yearly for population monitoring. Estimates of age, growth, and mortality, as well as population models, were used in the study to monitor triploid grass carp and predict population trends. Condition declined from that measured during a previous study in 1994. The annual mortality rate was estimated at 28% in 1997, 32% in 1998 and 39% in 1999; however, only the 1999 mortality rate was significantly different. Few (2 out of 98) of the triploid grass carp collected during 1999 were older than age 9. We expect increased mortality due to an aging population and sparse hydrilla coverage. During 1999, we estimated about 63,000 triploid grass carp system wide and project less than 3,000 fish by 2004, assuming no future stocking. management, population size Ctenopharyngodon idella, Hydrill

Combinatorial pulse position modulation for power-efficient free-space laser communications

A new modulation technique called combinatorial pulse position modulation (CPPM) is presented as a power-efficient alternative to quaternary pulse position modulation (QPPM) for direct-detection, free-space laser communications. The special case of 16C4PPM is compared to QPPM in terms of data throughput and bit error rate (BER) performance for similar laser power and pulse duty cycle requirements. The increased throughput from CPPM enables the use of forward error corrective (FEC) encoding for a net decrease in the amount of laser power required for a given data throughput compared to uncoded QPPM. A specific, practical case of coded CPPM is shown to reduce the amount of power required to transmit and receive a given data sequence by at least 4.7 dB. Hardware techniques for maximum likelihood detection and symbol timing recovery are presented

Production of FAME biodiesel in E. coli by direct methylation with an insect enzyme.

Most biodiesel currently in use consists of fatty acid methyl esters (FAMEs) produced by transesterification of plant oils with methanol. To reduce competition with food supplies, it would be desirable to directly produce biodiesel in microorganisms. To date, the most effective pathway for the production of biodiesel in bacteria yields fatty acid ethyl esters (FAEEs) at up to ~1.5 g/L. A much simpler route to biodiesel produces FAMEs by direct S-adenosyl-L-methionine (SAM) dependent methylation of free fatty acids, but FAME production by this route has been limited to only ~16 mg/L. Here we employ an alternative, broad spectrum methyltransferase, Drosophila melanogaster Juvenile Hormone Acid O-Methyltransferase (DmJHAMT). By introducing DmJHAMT in E. coli engineered to produce medium chain fatty acids and overproduce SAM, we obtain medium chain FAMEs at titers of 0.56 g/L, a 35-fold increase over titers previously achieved. Although considerable improvements will be needed for viable bacterial production of FAMEs and FAEEs for biofuels, it may be easier to optimize and transport the FAME production pathway to other microorganisms because it involves fewer enzymes

Nematic Fermi Fluids in Condensed Matter Physics

Correlated electron fluids can exhibit a startling array of complex phases, among which one of the more surprising is the electron nematic, a translationally invariant metallic phase with a spontaneously generated spatial anisotropy. Classical nematics generally occur in liquids of rod-like molecules; given that electrons are point-like, the initial theoretical motivation for contemplating electron nematics came from thinking of the electron fluid as a quantum melted electron crystal, rather than a strongly interacting descendent of a Fermi gas. That such phases exist in nature was established by dramatic transport experiments in ultra-clean quantum Hall systems in 1999 and in Sr3Ru2O7 in a strong magnetic field in 2007. In this paper, we briefly review the theoretical considerations governing nematic order, summarize the quantum Hall and Sr3Ru2O7 experiments that unambiguously establish the existence of this phase, and survey some of the current evidence for such a phase in the cuprate and Fe-based high temperature superconductors.Comment: 30 pages, 7 figures (some in color); to appear in Annual Reviews of Condensed Matter Physics. Edited version

Reconfigurable Computing for Speech Recognition: Preliminary Findings

Continuous real-time speech recognition is a highly computationally-demanding task, but one which can take good advantage of a parallel processing system. To this end, we describe proposals for, and preliminary findings of, research in implementing in programmable logic the decoder part of a speech recognition system. Recognition via Viterbi decoding of Hidden Markov Models is outlined, along with details of current implementations, which aim to exploit properties of the algorithm that could make it well-suited for devices such as FPGAs. The question of how to deal with limited resources, by reconfiguration or otherwise, is also addressed