Propulsion estimation techniques

A brief overview of statistical tools needed to perform post flight/test reconstruction of state variables is given. Linear regression, recursive linear regression, and the exact connection between the Kalman filter and linear regression are discussed. The regression connection is expected to serve as an aid in the application of a recently developed analytical method of flight reconstruction to single engine test firing data

SSME propulsion performance reconstruction techniques

In view of the complex flight operation of the Space Shuttle propulsion system together with an expected launch rate increase, the flight performance reconstruction process needs to be performed by automated computer programs. These programs must have the capability to quickly and reliably determine the true behavior of the various components of the propulsion system. For the flight reconstruction, measured values from the solid rocket motors, liquid engines, and trajectory are appraised through the Kalman filter technique to identify the most likely flight propulsion performance. A more detailed data collection program for the single SSME engine captive test firing evaluation is scheduled for startup in September of 1988. Engine performance evaluation for the captive test firing requires a reconstruction process that is similar to the process that is used for the flight reconstruction. Analytical tools that may be used to reconstruct a propulsion system's true performance under flight and/or test conditions are described

Statistical classification techniques for engineering and climatic data samples

Fisher's sample linear discriminant function is modified through an appropriate alteration of the common sample variance-covariance matrix. The alteration consists of adding nonnegative values to the eigenvalues of the sample variance covariance matrix. The desired results of this modification is to increase the number of correct classifications by the new linear discriminant function over Fisher's function. This study is limited to the two-group discriminant problem

Statistical analysis of SSME system data

A statistical methodology to enhance the Space Shuttle Main Engine (SSME) performance prediction accuracy is proposed. This methodology was to be used in conjunction with existing SSME performance prediction computer codes to improve parameter prediction accuracy and to quantify that accuracy. However, after a review of related literature, researchers concluded that the proposed problem required a coverage of areas such as linear and nonlinear system theory, measurement theory, statistics, and stochastic estimation. Since state space theory is the foundation for a more complete study of each of the before mentioned areas, these researchers chose to refocus emphasis to cover the more specialized topic of state vector estimation procedures. State vector estimation was also selected because of current and future concerns by NASA for SSME performance evaluation; i.e., there is a current interest in an improved evaluation procedure for actual SSME post flight performance as well as for post static test performance of a single SSME. A current investigation of analytical methods may be used to improve test stand failure detection. This paper considers the issue of post flight/test state variable reconstruction through the application of observations made on the output of the Space Shuttle propulsion system. Rogers used the Kalman filtering procedure to reconstruct the state variables of the Space Shuttle propulsion system. An objective of this paper is to give the general setup of the Kalman filter and its connection to linear regression. A second objective is to examine the reconstruction methodology for application to the reconstruction of the state vector of a single Space Shuttle Main Engine (SSME) by using static test firing data

Survey of Human Mitochondrial Diseases Using New Genomic/Proteomic Tools

BACKGROUND. We have constructed Bayesian prior-based, amino-acid sequence profiles for the complete yeast mitochondrial proteome and used them to develop methods for identifying and characterizing the context of protein mutations that give rise to human mitochondrial diseases. (Bayesian priors are conditional probabilities that allow the estimation of the likelihood of an event - such as an amino-acid substitution - on the basis of prior occurrences of similar events.) Because these profiles can assemble sets of taxonomically very diverse homologs, they enable identification of the structurally and/or functionally most critical sites in the proteins on the basis of the degree of sequence conservation. These profiles can also find distant homologs with determined three-dimensional structures that aid in the interpretation of effects of missense mutations. RESULTS. This survey reports such an analysis for 15 missense mutations one insertion and three deletions involved in Leber's hereditary optic neuropathy, Leigh syndrome, mitochondrial neurogastrointestinal encephalomyopathy, Mohr-Tranebjaerg syndrome, iron-storage disorders related to Friedreich's ataxia, and hereditary spastic paraplegia. We present structural correlations for seven of the mutations. CONCLUSIONS. Of the 19 mutations analyzed, 14 involved changes in very highly conserved parts of the affected proteins. Five out of seven structural correlations provided reasonable explanations for the malfunctions. As additional genetic and structural data become available, this methodology can be extended. It has the potential for assisting in identifying new disease-related genes. Furthermore, profiles with structural homologs can generate mechanistic hypotheses concerning the underlying biochemical processes - and why they break down as a result of the mutations.United States Department of Energy (DE-FG02-98ER62558); National Science Foundation (DBI-9807993

A model of student engagement and academic achievement: the role of teacher-student relationships and teacher expectations

A MODEL OF STUDENT ENGAGEMENT AND ACADEMIC ACHIEVEMENT: THE ROLE OF TEACHER-STUDENT RELATIONSHIPS AND TEACHER EXPECTATIONS by AJA C. TEMPLE MAY 2012 Advisor: Dr. Jina Yoon Major: Educational Psychology Degree: Doctor of Philosophy The purpose of this study was to examine patterns of academic achievement among minority students and investigate teacher-student relationships, teachers\u27 classroom and future educational expectations for students, and students\u27 levels of classroom engagement in order to better understand their patterns of academic achievement. Participants (n=522) were students in grades four through six from a suburban district in Michigan. Student achievement varied according to both gender and ethnicity in this study. Teacher expectations did not differ as a function of gender or ethnicity. Perceptions of the teacher-student relationship differed significantly for Hispanic students, with males reporting more clarity of expectations, consistency of response, adjustment of teaching strategies, and instrumental help from their teachers. Engagement did not mediate the relation between teacher-student relationships and student achievement in this study, but was associated with student rule compliance. Student compliance was related to perceptions of the relationship. A separate model testing the associations between teacher-student relationships, teacher expectations, and student achievement was significant for both the full sample and African American subgroup. Perceiving higher teacher expectations predicted perceptions of more involvement, structure, and autonomy support from teachers. Perceived relationship was negatively associated with overall GPA. Higher achievement outcomes were associated with both teacher expectations and teacher-student relationships. A moderating effect of gender was supported in this study, showing the model as most relevant to the achievement of African American males

The probability of flaw detection and the probability of false calls in nondestructive evaluation equipment

The space industry has developed many composite materials that have high durability in proportion to their weights. Many of these materials have a likelihood for flaws that is higher than in traditional metals. There are also coverings (such as paint) that develop flaws that may adversely affect the performance of the system in which they are used. Therefore there is a need to monitor the soundness of composite structures. To meet this monitoring need, many nondestructive evaluation (NDE) systems have been developed. An NDE system is designed to detect material flaws and make flaw measurements without destroying the inspected item. Also, the detection operation is expected to be performed in a rapid manner in a field or production environment. Some of the most recent video-based NDE methodologies are shearography, holography, thermography, and video image correlation

Sexting and Mental Health: A School-based Longitudinal Study Among Youth in Texas

Background: Sexting has emerged as a common socio-cultural problem in our society today. Few studies have estimated the prevalence of sexting among younger middle school youth and even fewer have assessed the relationship between sexting and mental health outcomes like anxiety and depression symptoms among middle school youth. Objectives: To estimate the prevalence of sexting among sixth and seventh-grade middle school students in a large urban school district in Southeast Texas and to assess its relationship with mental health outcomes (both anxiety and depression) among these youth. Methods: A retrospective analysis of an existing three-year randomized, two-arm, nested longitudinal study was conducted. Associations between sexting and depression symptoms; and sexting and anxiety symptoms were assessed via univariate and multivariate logistic analysis. Results: The prevalence of sexting among sixth graders was found to be 12%. Compared to youth who were not engaged in sexting, engagement in sexting was associated with significantly increased odds of depression and anxiety symptoms. Conclusion: Sexting is common among youth and is associated with poorer mental health outcomes such as anxiety and depression among these youth, but further validation of these findings is needed

A “Fashionable Tailor” on Water Street:Nineteenth-century Tailor’s Chalks fromSt. John’s, Newfoundland

Excavations related to a large sewer construction project in St. John’s, Newfoundland exposed several examples of tailor’s chalk lost during the Great Fire of 1892. Made from pipe clay, these objects may be the first of their kind identified on an archaeological site in North America. This paper introduces the changing social and economic position of tailors and other clothing-related trades in St. John’s. Tailor’s chalks are discussed within the context of the clay tobacco pipe industry, particularly the non tobacco-related objects produced, and within the tailoring trade throughout the early modern period