8,994 research outputs found
Launch vehicle error sensitivity study
Booster trajectory optimization for launch vehicle range sensitivity analysi
FAME, a microprocessor based front-end analysis and modeling environment
Higher order software (HOS) is a methodology for the specification and verification of large scale, complex, real time systems. The HOS methodology was implemented as FAME (front end analysis and modeling environment), a microprocessor based system for interactively developing, analyzing, and displaying system models in a low cost user-friendly environment. The nature of the model is such that when completed it can be the basis for projection to a variety of forms such as structured design diagrams, Petri-nets, data flow diagrams, and PSL/PSA source code. The user's interface with the analyzer is easily recognized by any current user of a structured modeling approach; therefore extensive training is unnecessary. Furthermore, when all the system capabilities are used one can check on proper usage of data types, functions, and control structures thereby adding a new dimension to the design process that will lead to better and more easily verified software designs
Can Residential Mobility Programs Improve Human Capital?: Comparing Social Mechanisms in Two Different Programs
The Lost Fortune of the Virginiaman: Analyzing the History of the Beale Ciphers Using Historical Land Grants
Since the mid-19th century, the mystery of the Beale ciphers has confounded cryptanalysts, intelligence agencies, historians, and treasure hunters alike. Countless works of scholarship have analyzed the story, the ciphers, and possible locations for the massive buried treasure allegedly in rural Bedford County, Virginia. However, prior methodology applied to historiography on the subject has been unsuccessful in making headway in an understanding of the history and location of the Beale treasure. In examining prior scholarship in conjunction with recorded land grants and associated archaeological scholarship, this paper proposes a new direction for research into the Beale cipher mystery and new locations to search for the treasure. In addition, this paper provides explanations as to potential members of the Beale party as not previously identified. It can be concluded that the Beale treasure has likely been moved from its original location in Virginia, and that Thomas Beale was a real person despite limited records on the matter. It can also be concluded that George Strother and Roger Weightman were most likely members of the Beale party, and these new conclusions are crucial to any future efforts to locate a potential vault
Graduating into Lower Risk: Chlamydia and Trichomonas Prevalance among Community College Students and Graduates
Background: Community colleges enable youth from economically disadvantaged and minority populations to access college and may enable social mobility including improved health outcomes. However, educational health disparities studies rarely assess the health outcomes for community college graduates.
Methods: Chlamydia and trichomonas prevalence were assessed with nucleic acid based tests in a nationally representative sample of 6233 high school graduates (ages 18–25) from five educational levels: young adults without post-secondary credentials who were not enrolled in college, community college students, 4-year college students, associate’s degree, and bachelor’s degree. To reduce confounding between educational attainment and STI status, we used full matching to balance on 22 measures of demographics, socioeconomic status, educational factors, and sexual risk-taking. Estimates of associations between educational attainment and STI status were obtained from multivariate regression in the full (n=6233) and matched (n=1655) samples.
Results:Four-year college students (adjusted incidence rate ratio (IRR) = 0.41, 95% CI [0.27, 0.61], p
Conclusions: Community college students come from populations with greater health risks than 4-year college students, but community college graduation may reduce the likelihood of chlamydia infection. STI interventions can meet the needs of young adults who access college through community college by partnering with community college health clinics to encourage continued STI prevention, testing, and treatment after the intervention ends. Public health studies that use inclusive educational attainment measures that incorporate sub-baccalaureate credentials will better capture health disparities
Sound radiation from a high speed axial flow fan due to the inlet turbulence quadrupole interaction
A formula is obtained for the total acoustic power spectra radiated out the front of the fan as a function of frequency. The formula involves the design parameters of the fan as well as the statistical properties of the incident turbulence. Numerical results are calculated for values of the parameters in the range of interest for quiet fans tested at the Lewis Research Center. As in the dipole analysis, when the turbulence correlation lengths become equal to the interblade spacing, the predicted spectra exhibit peaks around the blade passing frequency and its harmonics. There has recently been considerable conjecture about whether the stretching of turbulent eddies as they enter a stationary fan could result in the inlet turbulence being the dominant source of pure tones from nontranslating fans. The results of the current analysis show that, unless the turbulent eddies become quite elongated, this noise source contributes predominantly to the broadband spectrum
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