Creating a Sample of Off-Color Galaxies Using Big Data Tools

This thesis begins an investigation into the presence of off-colored galaxies in the Sloan Digital Sky Survey. Through establishing the emergence and history of Astroinformatics, the thesis introduces the concepts surrounding both off-color galaxies and the Big Data tools helpful in analyzing the data to find them. A discussion of initial implementation methods and revised implementation due to difficulties with previous plans follows. Results are presented, with well in excess of 500,000 candidates for off-color galaxies present in the sample. Conclusions are then drawn regarding such a large sample and the implications this may have on the conventional understanding of galaxies. Future work and improvements to the project are discussed at length in the closing section

A Critical Examination Of Understanding’s Characteristics: Why, In A Sense, Understanding Is Unique

Is understanding a unique kind of epistemic state or simply another word for knowledge? Recently, there is a dispute in the literature between those, non-reductionists, who argue that we cannot reduce understanding to knowledge. Sliwa and Khalifa, two reductionists, on the other hand, argue that understanding is basically just another word for knowledge (if we are fairly comparing the two). After considering the dialectic between non-reductionists and reductionists, undogmatically, I argue that Sliwa\u27s arguments in favor of reductionism fail. Sliwa\u27s analytical argument in defense of reductionism is unsuccessful because a special kind of understanding, subjective understanding, can be independent of knowledge. And, Sliwa\u27s background argument in defense of reductionism fails because there can be epistemic asymmetries in skeptical scenarios. So, my thesis is that understanding is not necessarily reducible to knowledge. After all, a certain kind of understanding, subjective understanding, is both non-factive and compatible with certain kinds of epistemic luck, unlike knowledge. Understanding, in a sense, is unique

Forecast performance of implied volatility and the impact of the volatility risk premium

Forecasting volatility has received a great deal of research attention, with the relative performance of econometric models based on time-series data and option implied volatility forecasts often being considered. While many studies find that implied volatility is the preferred approach, a number of issues remain unresolved. Implied volatilities are risk-neutral forecasts of spot volatility, whereas time-series models are estimated on risk-adjusted or real world data of the underlying. Recently, an intuitive method has been proposed to adjust these risk-neutral forecasts into their risk-adjusted equivalents, possibly improving on their forecast accuracy. By utilising recent econometric advances, this paper considers whether these risk-adjusted forecasts are statistically superior to the unadjusted forecasts, as well as a wide range of model based forecasts. It is found that an unadjusted risk-neutral implied volatility is an inferior forecast. However, after adjusting for the risk premia it is of equal predictive accuracy relative to a number of model based forecasts.Implied volatility, volatility forecasts, volatility models, volatility risk premium, model confidence sets

Drag coefficients on razor clams in slightly fluidized granular media

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references.Razor clams are able to burrow deeply into granular media with only a small fraction of force required by traditional anchoring devices. It is hypothesized that the collapse of their shell and subsequent localized fluidization of the media is responsible for a large reduction in drag, thereby allowing the clam to burrow. A test setup comprised of a fluidized bed connected to a pump with an attached ball valve for flow regulation is constructed which allows testing of drag force in conditions similar to that the clam experiences, as well as in an environment void of wall effects. Testing is done using a dead clam attached to a stainless steel rod which is passed through the fluidized bed to obtain accurate data for the razor clam. The result is that a slight fluidization to a void fraction between 40-45% gives a drag reduction which is more than sufficient for a clam to burrow at velocities seen in nature.by Christopher R. Becker.S.B

Control strategy for autonomous remediation of marine oil spills

Thesis (M.S.)--Boston UniversityThis thesis presents a novel formulation of a gradient-type controller to address the problem of cleaning up marine oil spills. Little work appears to have been done in developing autonomous oil spill clean-up devices, with most research efforts directed toward developing improved oil collection strategies. It does not appear that previous work in this field has included development of control algorithms specific to addressing the problem of deployment strategies for multiple clean-up devices. This thesis provides a framework for deployment of multiple clean-up agents and makes the following contributions to the field. We first develop a mathematical representation for the effect of a clean-up agent as a line-sink and introduce this term into an existing oil spill spreading model. The augmented oil spill spreading model is simulated for a finite volume of oil released within a region Q' which contains multiple clean-up agents. Second, we use the augmented oil spreading model to develop a cost function and derive a gradient controller that seeks to maximize the oil removal rate for a system of N clean-up agents. Several key properties of the controller are presented. Finally, we demonstrate the effectiveness of our controller through a MATLAB simulation. The performance of the controlled agents, measured by the total volume of oil removed over the simulation, is compared to the performance of static and randomly moving clean-up agents. The results from MATLAB simulations presented in this thesis demonstrate that the proposed control strategy is more effective at removing oil than static or randomly moving agents. The formulation of the control law directs clean-up devices toward areas in Q' experiencing the greatest volumetric change in oil, thereby maximizing the volume of oil that is removed by each agent. The controller presented in this thesis is adaptable to a range of clean-up devices and we present several future research avenues that could be pursued to further develop this concept

A study of translunar trajectories for a small satellite navigation and communications mission

Analysis was done to determine fuel optimal translunar trajectories from Earth geostationary transfer orbit to a specified target lunar orbit for a small satellite navigation and communication mission. The study included the optimization of impulsive and finite burn transfers. The inclusion of finite burns was necessary due to the low thrust nature of a small satellite propulsion system. Finite burn optimization was achieved using suboptimal parameterization control theory. The orbital parameters of the initial Earth orbit as well as the target lunar orbit were varied to see how this affected the optimal transfer results. Additionally, two engine thrust levels were explored to find the impact on the fuel mass required. All optimization analyses were completed using Copernicus, a trajectory optimization software package developed at the University of Texas at Austin for the National Aeronautics and Space Administration (NASA)

Phylloplane microflora from apple varieties resistant and susceptible to Venturia inaequalis and possible antagonism to the apple scab fungus.

Thesis (M.S.

A New Surface Analytical Technique with Ion and Laser Beams

This paper reviews recent results and developments, while presenting some new information, regarding the development of a novel surface analytical technique that uses nonresonant multiphoton ionization (MPI) of neutral atoms and molecules sputtered by an ion beam, or desorbed by an electron or second laser beam or by thermal means. In this method, called surface analysis by laser ionization (SALI), the nonresonant MPI, or laser ionization, is coupled with state-of-the-art time-of-flight mass spectrometry to provide extremely sensitive, general, and readily quantifiable surface analysis. A discussion also describes the favorable prospects for implementation of SALI with submicron dimension liquid metal ion beams for microanalysis, including situations with electron beam sensitive samples