2014 Summer Fellowship Award Recipients (Select the blue text below to expand the project description)
Ginger Denton, Ph.D., Humanities Department (More...)
“Who Participates? An Analysis of Political Behavior in Ten Asian Countries”
This research addresses a fundamental empirical question of who participates in Asian politics, why they do so, and what types of participation exist. Knowing who participates in politics in Asia and why they participate is invariably useful knowledge for a number of actors. Central to the overall theory is that there are certain elements in society and within the individual that can explain political phenomena no matter what region of the world one resides. I hypothesize that several individual level theories including that of the Resource Model can also be used in Asia. This goes against the conventional wisdom that Asia has a history of being a traditional society and therefore its culture would preclude it from being explained by more Western theories.
National probability sample survey data will be used from ten Asian countries for this project. The overall dataset includes questions asked of 16,000+ individuals to gauge the frequency in which one participates in a particular political action. A large set of socioeconomic factors were recorded from the respondents as well. These questions are used to test my hypotheses about the relationship between income, education, age, gender, etc. and the propensity to vote, campaign, protest, join a political activist group, etc. While some of the hypotheses have been tested many times over the past few decades in the United States, there has been no systematic test of them in Asia. The quantitative methods employed include basic statistical analysis such as regression and factor analysis, as well as time series and general linear models.
Karen Wink, Ph.D., Humanities Department (More...)
“CGA Worktext for Writing Skills”
During the past five years, students entering the CGA have shown rising challenges with critical writing and reading skills. Perhaps we are seeing the result of the “internet generation" in which students reduce–rather than elucidate–their written expression. In addition, their reading has become more perfunctory and entails searching for exact information rather than being purposeful and comprehensive. VSAT and VACT scores as well as “in-house” assessments: swab-placement essays and Diagnostic Test of Language Skills (DTLS) exhibit a concerning decline in cadets’ literacy. This trend shows particularly at the sentence-level of students’ writing. To counter this trend, I propose to write a workbook (newer word: “worktext”) similar in purpose to the USAFA’s text in which students review and practice writing skills such as decreasing passive voice, using commas adeptly, and incorporating college-level diction.
Within the speech and essay assignments, CGA’s English courses address conventions (grammar, punctuation, and syntax), but the increasing need for review of sentence-level skills (not unlike the need for some students to review fundamental mathematic skills) has intensified and calls for supplementary curriculum. Truly, we need an “in-house” worktext that students keep with them all four years as a reference from paper #1 in 4/c English to their senior projects. The content will display CG-related topics for high interest and applicability to writing strengthened, coherent sentences for writing assignments in diverse majors. Furthermore, this project supports the CGA’s Shared Learning Outcome of Communication Skills and the ensign’s “OER, Section ‘Communication Skills’” section, specifically:
Written material clear, concise, and logically organized. Proofread
conscientiously. Correspondence grammatically correct, tailored to
audience, and delivered by an appropriate medium.
Eric Page, Ph.D., Science Department (More...)
"Supercontinuum Generation for Optical Bioterror Detection"
2013 Summer Fellowship Award Recipients (Select the blue text below to expand the project description)
Devices based on nonlinear fiber optics hold promise as extremely sensitive detection systems. In such systems, light has a strong enough interaction with the material of the optical fibers to change fundamental properties of the light – phase and color for example. Using a new class of optical fibers, known as photonic crystal fibers, the goal of my summer research problem was to build a pulsed figure-8 fiber optics laser with the correct properties to induce white-light production in photonic crystal fibers (a process known as supercontinuum generation). Although numerous working pulsed fiber lasers were constructed and tested over the summer, none was capable of producing stable white light.
LT Victoria Futch, Science Department, Marine Science section (More...)
“Quantifying Dispersion Patterns in Island-Induced Flows as a Means to Improve Drift Prediction Accuracy.”
As the North Equatorial Current (NEC) passes the southernmost point of the island of Hawaiʾi, it separates into a shear layer which is unstable, forming vigorous anticyclonic vortices recurrently observed west of the island. To fully understand the dynamics of vortex formation and growth, the areas of the separation point and downstream must be observed in three dimensions.
Three High Frequency Doppler Radios will be deployed, one configured at high resolution to map the origin of the shear layer, and two configured for long range to map the subsequent growth of the vortices. Seventy surface drifters will be deployed in lines crossing the shear layer, and in clusters seeding emerging vortices, to obtain Lagrangian sampling of the flow. Two shipboard cruises using ADCP and hydrography, and three ADCP moorings, will provide the vertical structure of the vortices.
Strong negative wind stress curl in the lee of the island provides a competing mechanism for anticyclonic vortex formation, resulting in a Stommel-gyre extending west of the island into the interior, and a predicted counter-current. It is hypothesized that this Hawaii Lee Countercurrent (HLCC) is forced mostly by the transfer of zonal momentum by the instability vortices, wind stress curl playing a secondary, and possibly preconditioning, role.
The proposed observations will help determine which vortex formation mechanism dominates, a step to understand the dynamics of the HLCC. Improved statistics on seasonal patterns of the strength and location of the HLCC, a current influencing a large area of the subtropical pacific, will be obtained. The results will help constrain models and improve drift prediction in the region. In addition, a better understanding of the vortices will reveal characteristics such as thermocline depth, mixing, and related biological productivity effects.
Dr. Elisha Garcia, Engineering Department, Naval Architecture and Marine Engineering section (More...)
“Effect of Damping on VIV and Galloping of Arrays of Circular Cylinders when Analyzed with Variable Added Mass.”
Collaborator: Dr. Michael M. Bernitsas, Professor of VIVACE research group at the University of Michigan.
Description: Vortex-Induced Vibrations (VIV) and galloping are two vibration phenomena that have been known to exist for hundreds of years, but neither is fully understood. VIV and galloping are international fields, encompassing analytical, numerical, and experimental studies. The reason for this vast interest in VIV and galloping is the large forces that can be experienced by structures (offshore structures, bridges, towers, etc.) exposed to flow can be catastrophic. There are countless references to VIV or galloping leading to the fatigue and failure of structures. A better understanding of these phenomena can lead to better mitigation of failures.
For many decades, the idea that VIV can be successfully modeled as a lock-in phenomenon of a mass-spring-dashpot system with an ideal added mass term has persisted. In 2000, it was suggested by Vikestad et al. that VIV may be modeled better as a resonance phenomenon with variable natural frequency due to a variable added-mass term. Recently, Vandiver suggested a new dimensionless damping parameter c* that requires further vetting.
In this research project, the variable added-mass approach will be used for analysis of VIV and galloping of arrays of multiple cylinders. I have found for a single cylinder that a variable natural frequency due to variable added mass will be equal to the forcing frequency (and the frequency of oscillation) when the cylinders are in VIV, and the expectation is that the same will hold for multiple cylinder arrangements. This hypothesis can be further tested when the cylinders are in galloping triggered by passive turbulence control (PTC) in the form of sand strips. Additionally, experimental data on VIV and galloping of PTC-cylinders with variable damping will be analyzed in order to assess the effect of damping on variable added-mass and the validity of the new dimensionless damping parameter c*.
Experimental time-displacement data for VIV and galloping with varying stiffness and damping coefficient will be analyzed to extract a time-averaged added mass over each oscillation period of the data. Time-derivatives, corrected for phase-shift filtering, provide velocity and acceleration used to reconstruct the lift force as a function of time from the mass-spring-dashpot system. From this, the added mass can then be calculated for each specific test by extracting the term in phase with the acceleration. That is, by integrating the force multiplied by the acceleration. A time-averaged variable added mass will then be calculated by averaging all periods of oscillation for a given data set.
2012 Summer Fellowship Award Recipients
Dr. Susan B. Swithenbank, Engineering Department, Naval Architecture and Marine Engineering section (More...)
When using the theory of time sharing of frequencies for predicting damage and fatigue from Vortex-Induced Vibrations (VIV), the percent of time that a riser is vibrating with high amplitude VIV will significantly influence the fatigue rate of a riser. To accurately predict the fatigue of a riser using time sharing or another stochastic prediction method an accurate model is needed of the percent of time spent at these high amplitude vibrations.
Using model test data with both sheared and uniform flow, the percent of time that each section of a riser vibrated at high amplitude was determined. The larger issue was determining the factors that control the percentage of time at high amplitude vibration. Energy in the system was determined to be the largest influence on the percentage of time. At both low levels and high levels of energy the system had a low percentage of high amplitude VIV. For a middle set of energy the produced high amplitude VIV.
CDR Michael Corl, Engineering Department, Naval Architecture and Marine Engineering section (More...)
"Optimal Commonality Decisions"
A methodology is presented for the determination of the Pareto optimal choice of components and elements to make common between two different classes of military vessels. The use of commonality can produce fleet wide savings in component purchasing, training, spare parts, vessel construction, etc. The methodology presented here determines the optimal commonality decision and designs the vessel classes to maximize the mission performance per average acquisition cost of each vessel class and the total fleet saving achieved by the commonality. A customized evolutionary algorithm is used to determine the resulting discrete Pareto surface. The methodology is illustrated by its application to the design of two ship classes to perform the specific missions of the U.S. Coast Guard’s National Security Cutter and the Offshore Patrol Cutter. The results show that the methodology is effective and that not all commonality choices produce a net savings.
CDR Michael Corl, Engineering Department, Naval Architecture and Marine Engineering section (More...)
Study of the Use of Probabilistic Damage Stability Criteria for Offshore Supply Vessels (Ongoing)
In the summer of 2012, a study began that explored the possible application of probabilistic damage stability requirements for offshore supply vessels (OSVs). These unique and highly specialized vessels are currently built using a deterministic approach to damage stability. However, as OSVs grow larger in size, it is expected that they will have to use SOLAS probabilistic damage requirements for cargo vessels, or passenger vessels if they carry more than 240 passengers. Using 20 sample OSVs that meet the deterministic requirements, this study will examine whether or not these ships will meet the probabilistic requirements. The results will show which rules are more conservative and whether or not the rules can be considered equivalent.
This study is in cooperation with Mr. Brian Thomas of the U.S. Coast Guard Marine Safety Center. During the late summer and early fall, LCDR Cost also became involved due to his ability to use the GHS Software and personal interest in the material. Work has been done to become familiar with the probabilistic damage stability requirements and how they can be applied to this type of vessel. Probabilistic damage stability was used in the NA&ME senior design class for the evaluation of Arctic OSV designs to increase familiarity with the software and better understand its application and limitations. Anticipate further work being performed in the summer of 2013 with a goal of publishing a paper on the results.
Dr. Tooran Emami, Engineering Department, Electrical Engineering section (More...)
"Predicting the Robustness of a Heading Controller for a Two-Meter Autonomous Sailing Vessel"
The results of my CAS fellowship presents some of the successful design methodologies used to predict the robustness of a heading controller for a 2 meter autonomous sailing vessel. A graphical technique is introduced to estimate the discrete-time proportional integral derivative (PID) controller coefficients to satisfy H-infinity complementary sensitivity constraints for vessel control. This research shows that this problem can be solved by finding all achievable PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. Experimental data taken from this vessel at the U. S. Coast Guard Academy is used to demonstrate the application of this methodology.
My research started with an analysis of the two existing 1/c cadet design projects, the coordinating autonomous boating, and SailBot, in the Electrical Engineering Section at the U.S. Coast Guard Academy. This analysis included system identifications, modeling, simulation, and programming. My goal was to search for robust stability modeling and good performance for an autonomous vessel system. The Center for Advance Studies (CAS) Solicitation for summer allowed me to focus on applying some of the basic robust PID controller design theory to these applications. The controller design methodology that I ended up with is very simple and I hope to be very straight forward for our cadets.
Dr. Sam Wainwright, Science Department, Marine Science section (More...)
“Common Loons in the Gulf of Mexico” and “Photosynthesis in the Thames River”
I used my CAS fellowship to make progress on 2 research projects begun during my sabbatical in Spring 2012 and prior to that. One project, on “Common Loons in the Gulf of Mexico”, seeks to determine (1) whether these birds are being contaminated by oil while spending their winters in the Gulf of Mexico, and if so, (2) where are they spending their time and what are they eating? I analyzed blood samples for stable isotopes of nitrogen, carbon and sulfur. The results provide information on the habitat and diet of the birds, revealing that birds captured in 9 different habitats may show unique isotopic signatures. The isotopic data will be correlated with oil contamination data from another lab during the next phase of the project. In the second project, “Photosynthesis in the Thames River”, I collected monthly samples for the year ending in July 2012. Samples were analyzed for chlorophyll, photosynthesis and phytoplankton identification. The chlorophyll and inorganic carbon measurements are completed; photosynthesis measurements and phytoplankton IDs are ongoing. Phytoplankton abundance varied seasonally and in response to storm events.
(1) During the Deepwater Horizon oil spill in 2010, one of the hardest hit areas was Barataria Bay, south of New Orleans. Common loons (Gavia immer) migrate there for the winter from their summer breeding habitats in the upper Midwest. Starting in 2011, a research team from the Biodiversity Research Institute has been capturing loons at night, taking blood samples, and analyzing them for a wide variety of things including traces of oil contamination (PAHs), genetics, ecotoxicology, immunology, blood cell abnormalities. I got involved in the project in 2012 and added stable isotope analysis to that list. During my CAS fellowship I analyzed blood samples for stable isotopes of nitrogen (N), carbon (C) and sulfur (S). The C and S isotopes are correlated with the habit in which the birds are feeding, and N isotopes correlate with their level in the food chain, e.g., carnivore vs. omnivore. (2) The abundance and growth rate of phytoplankton are 2 of the most fundamental measurements that can be made on marine ecosystems. Yet, to my knowledge, no published measurements are available for the Thames River.
For more information on the CAS fellowships, contact Dr. Lucy Vlietstra.